Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/printk.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * Modified to make sys_syslog() more flexible: added commands to | |
7 | * return the last 4k of kernel messages, regardless of whether | |
8 | * they've been read or not. Added option to suppress kernel printk's | |
9 | * to the console. Added hook for sending the console messages | |
10 | * elsewhere, in preparation for a serial line console (someday). | |
11 | * Ted Ts'o, 2/11/93. | |
12 | * Modified for sysctl support, 1/8/97, Chris Horn. | |
40dc5651 | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
624dffcb | 14 | * manfred@colorfullife.com |
1da177e4 | 15 | * Rewrote bits to get rid of console_lock |
e1f8e874 | 16 | * 01Mar01 Andrew Morton |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/tty_driver.h> | |
1da177e4 LT |
23 | #include <linux/console.h> |
24 | #include <linux/init.h> | |
bfe8df3d RD |
25 | #include <linux/jiffies.h> |
26 | #include <linux/nmi.h> | |
1da177e4 | 27 | #include <linux/module.h> |
3b9c0410 | 28 | #include <linux/moduleparam.h> |
1da177e4 | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/smp.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/bootmem.h> | |
162a7e75 | 34 | #include <linux/memblock.h> |
a27bb332 | 35 | #include <linux/aio.h> |
1da177e4 | 36 | #include <linux/syscalls.h> |
04d491ab | 37 | #include <linux/kexec.h> |
d37d39ae | 38 | #include <linux/kdb.h> |
3fff4c42 | 39 | #include <linux/ratelimit.h> |
456b565c | 40 | #include <linux/kmsg_dump.h> |
00234592 | 41 | #include <linux/syslog.h> |
034260d6 KC |
42 | #include <linux/cpu.h> |
43 | #include <linux/notifier.h> | |
fb842b00 | 44 | #include <linux/rculist.h> |
e11fea92 | 45 | #include <linux/poll.h> |
74876a98 | 46 | #include <linux/irq_work.h> |
196779b9 | 47 | #include <linux/utsname.h> |
1da177e4 LT |
48 | |
49 | #include <asm/uaccess.h> | |
50 | ||
95100358 JB |
51 | #define CREATE_TRACE_POINTS |
52 | #include <trace/events/printk.h> | |
53 | ||
3c2a0909 S |
54 | #ifdef CONFIG_SEC_DEBUG |
55 | #include <linux/sec_debug.h> | |
56 | #endif | |
57 | ||
58 | #ifdef CONFIG_EARLY_PRINTK_DIRECT | |
59 | extern void printascii(char *); | |
60 | #endif | |
61 | ||
1da177e4 | 62 | /* printk's without a loglevel use this.. */ |
5af5bcb8 | 63 | #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
1da177e4 LT |
64 | |
65 | /* We show everything that is MORE important than this.. */ | |
66 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ | |
67 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ | |
68 | ||
1da177e4 LT |
69 | int console_printk[4] = { |
70 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ | |
71 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ | |
72 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ | |
73 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ | |
74 | }; | |
75 | ||
1da177e4 | 76 | /* |
0bbfb7c2 | 77 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
78 | * their unblank() callback or not. So let's export it. |
79 | */ | |
80 | int oops_in_progress; | |
81 | EXPORT_SYMBOL(oops_in_progress); | |
82 | ||
83 | /* | |
84 | * console_sem protects the console_drivers list, and also | |
85 | * provides serialisation for access to the entire console | |
86 | * driver system. | |
87 | */ | |
5b8c4f23 | 88 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 89 | struct console *console_drivers; |
a29d1cfe IM |
90 | EXPORT_SYMBOL_GPL(console_drivers); |
91 | ||
daee7797 DV |
92 | #ifdef CONFIG_LOCKDEP |
93 | static struct lockdep_map console_lock_dep_map = { | |
94 | .name = "console_lock" | |
95 | }; | |
96 | #endif | |
97 | ||
1da177e4 LT |
98 | /* |
99 | * This is used for debugging the mess that is the VT code by | |
100 | * keeping track if we have the console semaphore held. It's | |
101 | * definitely not the perfect debug tool (we don't know if _WE_ | |
102 | * hold it are racing, but it helps tracking those weird code | |
103 | * path in the console code where we end up in places I want | |
104 | * locked without the console sempahore held | |
105 | */ | |
557240b4 | 106 | static int console_locked, console_suspended; |
1da177e4 | 107 | |
fe3d8ad3 FT |
108 | /* |
109 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
110 | */ | |
111 | static struct console *exclusive_console; | |
112 | ||
1da177e4 LT |
113 | /* |
114 | * Array of consoles built from command line options (console=) | |
115 | */ | |
116 | struct console_cmdline | |
117 | { | |
62de970a | 118 | char name[16]; /* Name of the driver */ |
1da177e4 LT |
119 | int index; /* Minor dev. to use */ |
120 | char *options; /* Options for the driver */ | |
f7511d5f ST |
121 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
122 | char *brl_options; /* Options for braille driver */ | |
123 | #endif | |
1da177e4 LT |
124 | }; |
125 | ||
126 | #define MAX_CMDLINECONSOLES 8 | |
127 | ||
128 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
129 | static int selected_console = -1; | |
130 | static int preferred_console = -1; | |
9e124fe1 MA |
131 | int console_set_on_cmdline; |
132 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
133 | |
134 | /* Flag: console code may call schedule() */ | |
135 | static int console_may_schedule; | |
136 | ||
7ff9554b KS |
137 | /* |
138 | * The printk log buffer consists of a chain of concatenated variable | |
139 | * length records. Every record starts with a record header, containing | |
140 | * the overall length of the record. | |
141 | * | |
142 | * The heads to the first and last entry in the buffer, as well as the | |
143 | * sequence numbers of these both entries are maintained when messages | |
144 | * are stored.. | |
145 | * | |
146 | * If the heads indicate available messages, the length in the header | |
147 | * tells the start next message. A length == 0 for the next message | |
148 | * indicates a wrap-around to the beginning of the buffer. | |
149 | * | |
150 | * Every record carries the monotonic timestamp in microseconds, as well as | |
151 | * the standard userspace syslog level and syslog facility. The usual | |
152 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
153 | * a matching syslog facility, by default LOG_USER. The origin of every | |
154 | * message can be reliably determined that way. | |
155 | * | |
156 | * The human readable log message directly follows the message header. The | |
157 | * length of the message text is stored in the header, the stored message | |
158 | * is not terminated. | |
159 | * | |
e11fea92 KS |
160 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
161 | * to provide userspace with a machine-readable message context. | |
162 | * | |
163 | * Examples for well-defined, commonly used property names are: | |
164 | * DEVICE=b12:8 device identifier | |
165 | * b12:8 block dev_t | |
166 | * c127:3 char dev_t | |
167 | * n8 netdev ifindex | |
168 | * +sound:card0 subsystem:devname | |
169 | * SUBSYSTEM=pci driver-core subsystem name | |
170 | * | |
171 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
172 | * follows directly after a '=' character. Every property is terminated by | |
173 | * a '\0' character. The last property is not terminated. | |
174 | * | |
175 | * Example of a message structure: | |
176 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
177 | * 0008 34 00 record is 52 bytes long | |
178 | * 000a 0b 00 text is 11 bytes long | |
179 | * 000c 1f 00 dictionary is 23 bytes long | |
180 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
181 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
182 | * 69 6e 65 "ine" | |
183 | * 001b 44 45 56 49 43 "DEVIC" | |
184 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
185 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
186 | * 67 "g" | |
187 | * 0032 00 00 00 padding to next message header | |
188 | * | |
189 | * The 'struct log' buffer header must never be directly exported to | |
190 | * userspace, it is a kernel-private implementation detail that might | |
191 | * need to be changed in the future, when the requirements change. | |
192 | * | |
193 | * /dev/kmsg exports the structured data in the following line format: | |
194 | * "level,sequnum,timestamp;<message text>\n" | |
195 | * | |
196 | * The optional key/value pairs are attached as continuation lines starting | |
197 | * with a space character and terminated by a newline. All possible | |
198 | * non-prinatable characters are escaped in the "\xff" notation. | |
199 | * | |
200 | * Users of the export format should ignore possible additional values | |
201 | * separated by ',', and find the message after the ';' character. | |
7ff9554b KS |
202 | */ |
203 | ||
084681d1 | 204 | enum log_flags { |
5becfb1d KS |
205 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
206 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
207 | LOG_PREFIX = 4, /* text started with a prefix */ | |
208 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
209 | }; |
210 | ||
7ff9554b KS |
211 | struct log { |
212 | u64 ts_nsec; /* timestamp in nanoseconds */ | |
213 | u16 len; /* length of entire record */ | |
214 | u16 text_len; /* length of text buffer */ | |
215 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
216 | u8 facility; /* syslog facility */ |
217 | u8 flags:5; /* internal record flags */ | |
218 | u8 level:3; /* syslog level */ | |
3c2a0909 S |
219 | #ifdef CONFIG_PRINTK_PROCESS |
220 | char process[16]; /* process name */ | |
221 | pid_t pid; /* process id */ | |
222 | u8 cpu; /* cpu id */ | |
223 | u8 in_interrupt; /* interrupt context */ | |
224 | #endif | |
7ff9554b KS |
225 | }; |
226 | ||
227 | /* | |
228 | * The logbuf_lock protects kmsg buffer, indices, counters. It is also | |
229 | * used in interesting ways to provide interlocking in console_unlock(); | |
230 | */ | |
231 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 232 | |
96efedf1 | 233 | #ifdef CONFIG_PRINTK |
dc72c32e | 234 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
235 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
236 | static u64 syslog_seq; | |
237 | static u32 syslog_idx; | |
5becfb1d | 238 | static enum log_flags syslog_prev; |
eb02dac9 | 239 | static size_t syslog_partial; |
7ff9554b KS |
240 | |
241 | /* index and sequence number of the first record stored in the buffer */ | |
242 | static u64 log_first_seq; | |
243 | static u32 log_first_idx; | |
244 | ||
245 | /* index and sequence number of the next record to store in the buffer */ | |
246 | static u64 log_next_seq; | |
247 | static u32 log_next_idx; | |
248 | ||
eab07260 KS |
249 | /* the next printk record to write to the console */ |
250 | static u64 console_seq; | |
251 | static u32 console_idx; | |
252 | static enum log_flags console_prev; | |
253 | ||
7ff9554b KS |
254 | /* the next printk record to read after the last 'clear' command */ |
255 | static u64 clear_seq; | |
256 | static u32 clear_idx; | |
257 | ||
3c2a0909 S |
258 | #ifdef CONFIG_PRINTK_PROCESS |
259 | #define PREFIX_MAX 48 | |
260 | #else | |
70498253 | 261 | #define PREFIX_MAX 32 |
3c2a0909 | 262 | #endif |
70498253 | 263 | #define LOG_LINE_MAX 1024 - PREFIX_MAX |
7f3a781d KS |
264 | |
265 | /* record buffer */ | |
6ebb017d | 266 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
f8450fca SW |
267 | #define LOG_ALIGN 4 |
268 | #else | |
6ebb017d | 269 | #define LOG_ALIGN __alignof__(struct log) |
f8450fca | 270 | #endif |
7f3a781d | 271 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 272 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
273 | static char *log_buf = __log_buf; |
274 | static u32 log_buf_len = __LOG_BUF_LEN; | |
275 | ||
276 | /* cpu currently holding logbuf_lock */ | |
277 | static volatile unsigned int logbuf_cpu = UINT_MAX; | |
7ff9554b KS |
278 | |
279 | /* human readable text of the record */ | |
280 | static char *log_text(const struct log *msg) | |
281 | { | |
282 | return (char *)msg + sizeof(struct log); | |
283 | } | |
284 | ||
285 | /* optional key/value pair dictionary attached to the record */ | |
286 | static char *log_dict(const struct log *msg) | |
287 | { | |
288 | return (char *)msg + sizeof(struct log) + msg->text_len; | |
289 | } | |
290 | ||
291 | /* get record by index; idx must point to valid msg */ | |
292 | static struct log *log_from_idx(u32 idx) | |
293 | { | |
294 | struct log *msg = (struct log *)(log_buf + idx); | |
295 | ||
296 | /* | |
297 | * A length == 0 record is the end of buffer marker. Wrap around and | |
298 | * read the message at the start of the buffer. | |
299 | */ | |
300 | if (!msg->len) | |
301 | return (struct log *)log_buf; | |
302 | return msg; | |
303 | } | |
304 | ||
305 | /* get next record; idx must point to valid msg */ | |
306 | static u32 log_next(u32 idx) | |
307 | { | |
308 | struct log *msg = (struct log *)(log_buf + idx); | |
309 | ||
310 | /* length == 0 indicates the end of the buffer; wrap */ | |
311 | /* | |
312 | * A length == 0 record is the end of buffer marker. Wrap around and | |
313 | * read the message at the start of the buffer as *this* one, and | |
314 | * return the one after that. | |
315 | */ | |
316 | if (!msg->len) { | |
317 | msg = (struct log *)log_buf; | |
318 | return msg->len; | |
319 | } | |
320 | return idx + msg->len; | |
321 | } | |
322 | ||
3c2a0909 S |
323 | #ifdef CONFIG_PRINTK_PROCESS |
324 | static bool printk_process = 1; | |
325 | static size_t print_process(const struct log *msg, char *buf) | |
326 | ||
327 | { | |
328 | if (!printk_process) | |
329 | return 0; | |
330 | ||
331 | if (!buf) | |
332 | return snprintf(NULL, 0, "%c[%1d:%15s:%5d] ", ' ', 0, " ", 0); | |
333 | ||
334 | return sprintf(buf, "%c[%1d:%15s:%5d] ", | |
335 | msg->in_interrupt ? 'I' : ' ', | |
336 | msg->cpu, | |
337 | msg->process, | |
338 | msg->pid); | |
339 | } | |
340 | #else | |
341 | static bool printk_process = 0; | |
342 | static size_t print_process(const struct log *msg, char *buf) | |
343 | { | |
344 | return 0; | |
345 | } | |
346 | #endif | |
347 | module_param_named(process, printk_process, bool, S_IRUGO | S_IWUSR); | |
348 | ||
349 | #ifdef CONFIG_SEC_DEBUG | |
350 | void sec_debug_disable_printk_process(void) | |
351 | { | |
352 | printk_process = 0; | |
353 | } | |
354 | #endif | |
355 | ||
356 | #ifdef CONFIG_EXYNOS_SNAPSHOT | |
357 | static size_t hook_size; | |
358 | static char hook_text[LOG_LINE_MAX + PREFIX_MAX]; | |
359 | static void (*func_hook_logbuf)(const char *buf, size_t size); | |
360 | static size_t msg_print_text(const struct log *msg, enum log_flags prev, | |
361 | bool syslog, char *buf, size_t size); | |
362 | void register_hook_logbuf(void (*func)(const char *buf, size_t size)) | |
363 | { | |
364 | unsigned long flags; | |
365 | ||
366 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
367 | /* | |
368 | * In register hooking function, we should check messages already | |
369 | * printed on log_buf. If so, they will be copyied to backup | |
370 | * exynos log buffer | |
371 | * */ | |
372 | if (log_first_seq != log_next_seq) { | |
373 | unsigned int step_seq, step_idx, start, end; | |
374 | struct log *msg; | |
375 | start = log_first_seq; | |
376 | end = log_next_seq; | |
377 | step_idx = log_first_idx; | |
378 | for (step_seq = start; step_seq < end; step_seq++) { | |
379 | msg = (struct log *)(log_buf + step_idx); | |
380 | hook_size = msg_print_text(msg, msg->flags, | |
381 | true, hook_text, LOG_LINE_MAX + PREFIX_MAX); | |
382 | func(hook_text, hook_size); | |
383 | step_idx = log_next(step_idx); | |
384 | } | |
385 | } | |
386 | func_hook_logbuf = func; | |
387 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
388 | } | |
389 | EXPORT_SYMBOL(register_hook_logbuf); | |
390 | #endif | |
391 | ||
7ff9554b KS |
392 | /* insert record into the buffer, discard old ones, update heads */ |
393 | static void log_store(int facility, int level, | |
084681d1 | 394 | enum log_flags flags, u64 ts_nsec, |
7ff9554b KS |
395 | const char *dict, u16 dict_len, |
396 | const char *text, u16 text_len) | |
397 | { | |
398 | struct log *msg; | |
399 | u32 size, pad_len; | |
400 | ||
401 | /* number of '\0' padding bytes to next message */ | |
402 | size = sizeof(struct log) + text_len + dict_len; | |
403 | pad_len = (-size) & (LOG_ALIGN - 1); | |
404 | size += pad_len; | |
405 | ||
406 | while (log_first_seq < log_next_seq) { | |
407 | u32 free; | |
408 | ||
409 | if (log_next_idx > log_first_idx) | |
410 | free = max(log_buf_len - log_next_idx, log_first_idx); | |
411 | else | |
412 | free = log_first_idx - log_next_idx; | |
413 | ||
414 | if (free > size + sizeof(struct log)) | |
415 | break; | |
416 | ||
417 | /* drop old messages until we have enough contiuous space */ | |
418 | log_first_idx = log_next(log_first_idx); | |
419 | log_first_seq++; | |
420 | } | |
421 | ||
422 | if (log_next_idx + size + sizeof(struct log) >= log_buf_len) { | |
423 | /* | |
424 | * This message + an additional empty header does not fit | |
425 | * at the end of the buffer. Add an empty header with len == 0 | |
426 | * to signify a wrap around. | |
427 | */ | |
428 | memset(log_buf + log_next_idx, 0, sizeof(struct log)); | |
429 | log_next_idx = 0; | |
430 | } | |
431 | ||
432 | /* fill message */ | |
433 | msg = (struct log *)(log_buf + log_next_idx); | |
434 | memcpy(log_text(msg), text, text_len); | |
435 | msg->text_len = text_len; | |
436 | memcpy(log_dict(msg), dict, dict_len); | |
437 | msg->dict_len = dict_len; | |
084681d1 KS |
438 | msg->facility = facility; |
439 | msg->level = level & 7; | |
440 | msg->flags = flags & 0x1f; | |
441 | if (ts_nsec > 0) | |
442 | msg->ts_nsec = ts_nsec; | |
443 | else | |
444 | msg->ts_nsec = local_clock(); | |
7ff9554b KS |
445 | memset(log_dict(msg) + dict_len, 0, pad_len); |
446 | msg->len = sizeof(struct log) + text_len + dict_len + pad_len; | |
447 | ||
3c2a0909 S |
448 | #ifdef CONFIG_PRINTK_PROCESS |
449 | if (printk_process) { | |
450 | strncpy(msg->process, current->comm, sizeof(msg->process)); | |
451 | msg->pid = task_pid_nr(current); | |
452 | msg->cpu = smp_processor_id(); | |
453 | msg->in_interrupt = in_interrupt() ? 1 : 0; | |
454 | } | |
455 | #endif | |
456 | ||
457 | #ifdef CONFIG_EXYNOS_SNAPSHOT | |
458 | if (func_hook_logbuf) { | |
459 | hook_size = msg_print_text(msg, msg->flags, | |
460 | true, hook_text, LOG_LINE_MAX + PREFIX_MAX); | |
461 | func_hook_logbuf(hook_text, hook_size); | |
462 | } | |
463 | #endif | |
464 | ||
7ff9554b KS |
465 | /* insert message */ |
466 | log_next_idx += msg->len; | |
467 | log_next_seq++; | |
468 | } | |
d59745ce | 469 | |
637241a9 KC |
470 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
471 | int dmesg_restrict = 1; | |
472 | #else | |
473 | int dmesg_restrict; | |
474 | #endif | |
475 | ||
476 | static int syslog_action_restricted(int type) | |
477 | { | |
478 | if (dmesg_restrict) | |
479 | return 1; | |
480 | /* | |
481 | * Unless restricted, we allow "read all" and "get buffer size" | |
482 | * for everybody. | |
483 | */ | |
484 | return type != SYSLOG_ACTION_READ_ALL && | |
485 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
486 | } | |
487 | ||
488 | static int check_syslog_permissions(int type, bool from_file) | |
489 | { | |
490 | /* | |
491 | * If this is from /proc/kmsg and we've already opened it, then we've | |
492 | * already done the capabilities checks at open time. | |
493 | */ | |
494 | if (from_file && type != SYSLOG_ACTION_OPEN) | |
495 | return 0; | |
496 | ||
497 | if (syslog_action_restricted(type)) { | |
498 | if (capable(CAP_SYSLOG)) | |
499 | return 0; | |
500 | /* | |
501 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
502 | * a warning. | |
503 | */ | |
504 | if (capable(CAP_SYS_ADMIN)) { | |
505 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
506 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
507 | "(deprecated).\n", | |
508 | current->comm, task_pid_nr(current)); | |
509 | return 0; | |
510 | } | |
511 | return -EPERM; | |
512 | } | |
513 | return security_syslog(type); | |
514 | } | |
515 | ||
516 | ||
e11fea92 KS |
517 | /* /dev/kmsg - userspace message inject/listen interface */ |
518 | struct devkmsg_user { | |
519 | u64 seq; | |
520 | u32 idx; | |
d39f3d77 | 521 | enum log_flags prev; |
e11fea92 KS |
522 | struct mutex lock; |
523 | char buf[8192]; | |
524 | }; | |
525 | ||
526 | static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, | |
527 | unsigned long count, loff_t pos) | |
528 | { | |
529 | char *buf, *line; | |
530 | int i; | |
531 | int level = default_message_loglevel; | |
532 | int facility = 1; /* LOG_USER */ | |
533 | size_t len = iov_length(iv, count); | |
534 | ssize_t ret = len; | |
535 | ||
536 | if (len > LOG_LINE_MAX) | |
537 | return -EINVAL; | |
538 | buf = kmalloc(len+1, GFP_KERNEL); | |
539 | if (buf == NULL) | |
540 | return -ENOMEM; | |
541 | ||
542 | line = buf; | |
543 | for (i = 0; i < count; i++) { | |
cdf53441 KS |
544 | if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) { |
545 | ret = -EFAULT; | |
e11fea92 | 546 | goto out; |
cdf53441 | 547 | } |
e11fea92 KS |
548 | line += iv[i].iov_len; |
549 | } | |
550 | ||
551 | /* | |
552 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
553 | * the decimal value represents 32bit, the lower 3 bit are the log | |
554 | * level, the rest are the log facility. | |
555 | * | |
556 | * If no prefix or no userspace facility is specified, we | |
557 | * enforce LOG_USER, to be able to reliably distinguish | |
558 | * kernel-generated messages from userspace-injected ones. | |
559 | */ | |
560 | line = buf; | |
561 | if (line[0] == '<') { | |
562 | char *endp = NULL; | |
563 | ||
564 | i = simple_strtoul(line+1, &endp, 10); | |
565 | if (endp && endp[0] == '>') { | |
566 | level = i & 7; | |
567 | if (i >> 3) | |
568 | facility = i >> 3; | |
569 | endp++; | |
570 | len -= endp - line; | |
571 | line = endp; | |
572 | } | |
573 | } | |
574 | line[len] = '\0'; | |
575 | ||
576 | printk_emit(facility, level, NULL, 0, "%s", line); | |
577 | out: | |
578 | kfree(buf); | |
579 | return ret; | |
580 | } | |
581 | ||
582 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
583 | size_t count, loff_t *ppos) | |
584 | { | |
585 | struct devkmsg_user *user = file->private_data; | |
586 | struct log *msg; | |
5fc32490 | 587 | u64 ts_usec; |
e11fea92 | 588 | size_t i; |
d39f3d77 | 589 | char cont = '-'; |
e11fea92 KS |
590 | size_t len; |
591 | ssize_t ret; | |
592 | ||
593 | if (!user) | |
594 | return -EBADF; | |
595 | ||
4a77a5a0 YL |
596 | ret = mutex_lock_interruptible(&user->lock); |
597 | if (ret) | |
598 | return ret; | |
5c53d819 | 599 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
600 | while (user->seq == log_next_seq) { |
601 | if (file->f_flags & O_NONBLOCK) { | |
602 | ret = -EAGAIN; | |
5c53d819 | 603 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
604 | goto out; |
605 | } | |
606 | ||
5c53d819 | 607 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
608 | ret = wait_event_interruptible(log_wait, |
609 | user->seq != log_next_seq); | |
610 | if (ret) | |
611 | goto out; | |
5c53d819 | 612 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
613 | } |
614 | ||
615 | if (user->seq < log_first_seq) { | |
616 | /* our last seen message is gone, return error and reset */ | |
617 | user->idx = log_first_idx; | |
618 | user->seq = log_first_seq; | |
619 | ret = -EPIPE; | |
5c53d819 | 620 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
621 | goto out; |
622 | } | |
623 | ||
624 | msg = log_from_idx(user->idx); | |
5fc32490 KS |
625 | ts_usec = msg->ts_nsec; |
626 | do_div(ts_usec, 1000); | |
d39f3d77 KS |
627 | |
628 | /* | |
629 | * If we couldn't merge continuation line fragments during the print, | |
630 | * export the stored flags to allow an optional external merge of the | |
631 | * records. Merging the records isn't always neccessarily correct, like | |
632 | * when we hit a race during printing. In most cases though, it produces | |
633 | * better readable output. 'c' in the record flags mark the first | |
634 | * fragment of a line, '+' the following. | |
635 | */ | |
636 | if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT)) | |
637 | cont = 'c'; | |
638 | else if ((msg->flags & LOG_CONT) || | |
639 | ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))) | |
640 | cont = '+'; | |
641 | ||
642 | len = sprintf(user->buf, "%u,%llu,%llu,%c;", | |
643 | (msg->facility << 3) | msg->level, | |
644 | user->seq, ts_usec, cont); | |
645 | user->prev = msg->flags; | |
e11fea92 KS |
646 | |
647 | /* escape non-printable characters */ | |
648 | for (i = 0; i < msg->text_len; i++) { | |
3ce9a7c0 | 649 | unsigned char c = log_text(msg)[i]; |
e11fea92 | 650 | |
e3f5a5f2 | 651 | if (c < ' ' || c >= 127 || c == '\\') |
e11fea92 KS |
652 | len += sprintf(user->buf + len, "\\x%02x", c); |
653 | else | |
654 | user->buf[len++] = c; | |
655 | } | |
656 | user->buf[len++] = '\n'; | |
657 | ||
658 | if (msg->dict_len) { | |
659 | bool line = true; | |
660 | ||
661 | for (i = 0; i < msg->dict_len; i++) { | |
3ce9a7c0 | 662 | unsigned char c = log_dict(msg)[i]; |
e11fea92 KS |
663 | |
664 | if (line) { | |
665 | user->buf[len++] = ' '; | |
666 | line = false; | |
667 | } | |
668 | ||
669 | if (c == '\0') { | |
670 | user->buf[len++] = '\n'; | |
671 | line = true; | |
672 | continue; | |
673 | } | |
674 | ||
e3f5a5f2 | 675 | if (c < ' ' || c >= 127 || c == '\\') { |
e11fea92 KS |
676 | len += sprintf(user->buf + len, "\\x%02x", c); |
677 | continue; | |
678 | } | |
679 | ||
680 | user->buf[len++] = c; | |
681 | } | |
682 | user->buf[len++] = '\n'; | |
683 | } | |
684 | ||
685 | user->idx = log_next(user->idx); | |
686 | user->seq++; | |
5c53d819 | 687 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
688 | |
689 | if (len > count) { | |
690 | ret = -EINVAL; | |
691 | goto out; | |
692 | } | |
693 | ||
694 | if (copy_to_user(buf, user->buf, len)) { | |
695 | ret = -EFAULT; | |
696 | goto out; | |
697 | } | |
698 | ret = len; | |
699 | out: | |
700 | mutex_unlock(&user->lock); | |
701 | return ret; | |
702 | } | |
703 | ||
704 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
705 | { | |
706 | struct devkmsg_user *user = file->private_data; | |
707 | loff_t ret = 0; | |
708 | ||
709 | if (!user) | |
710 | return -EBADF; | |
711 | if (offset) | |
712 | return -ESPIPE; | |
713 | ||
5c53d819 | 714 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
715 | switch (whence) { |
716 | case SEEK_SET: | |
717 | /* the first record */ | |
718 | user->idx = log_first_idx; | |
719 | user->seq = log_first_seq; | |
720 | break; | |
721 | case SEEK_DATA: | |
722 | /* | |
723 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
724 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
725 | * changes no global state, and does not clear anything. | |
726 | */ | |
727 | user->idx = clear_idx; | |
728 | user->seq = clear_seq; | |
729 | break; | |
730 | case SEEK_END: | |
731 | /* after the last record */ | |
732 | user->idx = log_next_idx; | |
733 | user->seq = log_next_seq; | |
734 | break; | |
735 | default: | |
736 | ret = -EINVAL; | |
737 | } | |
5c53d819 | 738 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
739 | return ret; |
740 | } | |
741 | ||
742 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
743 | { | |
744 | struct devkmsg_user *user = file->private_data; | |
745 | int ret = 0; | |
746 | ||
747 | if (!user) | |
748 | return POLLERR|POLLNVAL; | |
749 | ||
750 | poll_wait(file, &log_wait, wait); | |
751 | ||
5c53d819 | 752 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
753 | if (user->seq < log_next_seq) { |
754 | /* return error when data has vanished underneath us */ | |
755 | if (user->seq < log_first_seq) | |
756 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
757 | else |
758 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 759 | } |
5c53d819 | 760 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
761 | |
762 | return ret; | |
763 | } | |
764 | ||
765 | static int devkmsg_open(struct inode *inode, struct file *file) | |
766 | { | |
767 | struct devkmsg_user *user; | |
768 | int err; | |
769 | ||
770 | /* write-only does not need any file context */ | |
771 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
772 | return 0; | |
773 | ||
637241a9 KC |
774 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, |
775 | SYSLOG_FROM_READER); | |
e11fea92 KS |
776 | if (err) |
777 | return err; | |
778 | ||
779 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
780 | if (!user) | |
781 | return -ENOMEM; | |
782 | ||
783 | mutex_init(&user->lock); | |
784 | ||
5c53d819 | 785 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
786 | user->idx = log_first_idx; |
787 | user->seq = log_first_seq; | |
5c53d819 | 788 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
789 | |
790 | file->private_data = user; | |
791 | return 0; | |
792 | } | |
793 | ||
794 | static int devkmsg_release(struct inode *inode, struct file *file) | |
795 | { | |
796 | struct devkmsg_user *user = file->private_data; | |
797 | ||
798 | if (!user) | |
799 | return 0; | |
800 | ||
801 | mutex_destroy(&user->lock); | |
802 | kfree(user); | |
803 | return 0; | |
804 | } | |
805 | ||
806 | const struct file_operations kmsg_fops = { | |
807 | .open = devkmsg_open, | |
808 | .read = devkmsg_read, | |
809 | .aio_write = devkmsg_writev, | |
810 | .llseek = devkmsg_llseek, | |
811 | .poll = devkmsg_poll, | |
812 | .release = devkmsg_release, | |
813 | }; | |
814 | ||
04d491ab NH |
815 | #ifdef CONFIG_KEXEC |
816 | /* | |
817 | * This appends the listed symbols to /proc/vmcoreinfo | |
818 | * | |
819 | * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to | |
820 | * obtain access to symbols that are otherwise very difficult to locate. These | |
821 | * symbols are specifically used so that utilities can access and extract the | |
822 | * dmesg log from a vmcore file after a crash. | |
823 | */ | |
824 | void log_buf_kexec_setup(void) | |
825 | { | |
826 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 827 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b KS |
828 | VMCOREINFO_SYMBOL(log_first_idx); |
829 | VMCOREINFO_SYMBOL(log_next_idx); | |
6791457a VG |
830 | /* |
831 | * Export struct log size and field offsets. User space tools can | |
832 | * parse it and detect any changes to structure down the line. | |
833 | */ | |
834 | VMCOREINFO_STRUCT_SIZE(log); | |
835 | VMCOREINFO_OFFSET(log, ts_nsec); | |
836 | VMCOREINFO_OFFSET(log, len); | |
837 | VMCOREINFO_OFFSET(log, text_len); | |
838 | VMCOREINFO_OFFSET(log, dict_len); | |
04d491ab NH |
839 | } |
840 | #endif | |
841 | ||
162a7e75 MT |
842 | /* requested log_buf_len from kernel cmdline */ |
843 | static unsigned long __initdata new_log_buf_len; | |
844 | ||
845 | /* save requested log_buf_len since it's too early to process it */ | |
1da177e4 LT |
846 | static int __init log_buf_len_setup(char *str) |
847 | { | |
eed4a2ab | 848 | unsigned size = memparse(str, &str); |
1da177e4 LT |
849 | |
850 | if (size) | |
851 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
852 | if (size > log_buf_len) |
853 | new_log_buf_len = size; | |
854 | ||
855 | return 0; | |
1da177e4 | 856 | } |
162a7e75 MT |
857 | early_param("log_buf_len", log_buf_len_setup); |
858 | ||
859 | void __init setup_log_buf(int early) | |
860 | { | |
861 | unsigned long flags; | |
162a7e75 MT |
862 | char *new_log_buf; |
863 | int free; | |
864 | ||
865 | if (!new_log_buf_len) | |
866 | return; | |
1da177e4 | 867 | |
162a7e75 MT |
868 | if (early) { |
869 | unsigned long mem; | |
870 | ||
871 | mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); | |
1f5026a7 | 872 | if (!mem) |
162a7e75 MT |
873 | return; |
874 | new_log_buf = __va(mem); | |
875 | } else { | |
876 | new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); | |
877 | } | |
878 | ||
879 | if (unlikely(!new_log_buf)) { | |
880 | pr_err("log_buf_len: %ld bytes not available\n", | |
881 | new_log_buf_len); | |
882 | return; | |
883 | } | |
884 | ||
07354eb1 | 885 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
886 | log_buf_len = new_log_buf_len; |
887 | log_buf = new_log_buf; | |
888 | new_log_buf_len = 0; | |
7ff9554b KS |
889 | free = __LOG_BUF_LEN - log_next_idx; |
890 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 891 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 MT |
892 | |
893 | pr_info("log_buf_len: %d\n", log_buf_len); | |
894 | pr_info("early log buf free: %d(%d%%)\n", | |
895 | free, (free * 100) / __LOG_BUF_LEN); | |
896 | } | |
1da177e4 | 897 | |
2fa72c8f AC |
898 | static bool __read_mostly ignore_loglevel; |
899 | ||
900 | static int __init ignore_loglevel_setup(char *str) | |
901 | { | |
902 | ignore_loglevel = 1; | |
903 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); | |
904 | ||
905 | return 0; | |
906 | } | |
907 | ||
908 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
909 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
910 | MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" | |
911 | "print all kernel messages to the console."); | |
912 | ||
bfe8df3d RD |
913 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
914 | ||
674dff65 | 915 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 916 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
917 | |
918 | static int __init boot_delay_setup(char *str) | |
919 | { | |
920 | unsigned long lpj; | |
bfe8df3d RD |
921 | |
922 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
923 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
924 | ||
925 | get_option(&str, &boot_delay); | |
926 | if (boot_delay > 10 * 1000) | |
927 | boot_delay = 0; | |
928 | ||
3a3b6ed2 DY |
929 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
930 | "HZ: %d, loops_per_msec: %llu\n", | |
931 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
bfe8df3d RD |
932 | return 1; |
933 | } | |
934 | __setup("boot_delay=", boot_delay_setup); | |
935 | ||
2fa72c8f | 936 | static void boot_delay_msec(int level) |
bfe8df3d RD |
937 | { |
938 | unsigned long long k; | |
939 | unsigned long timeout; | |
940 | ||
2fa72c8f AC |
941 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
942 | || (level >= console_loglevel && !ignore_loglevel)) { | |
bfe8df3d | 943 | return; |
2fa72c8f | 944 | } |
bfe8df3d | 945 | |
3a3b6ed2 | 946 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
947 | |
948 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
949 | while (k) { | |
950 | k--; | |
951 | cpu_relax(); | |
952 | /* | |
953 | * use (volatile) jiffies to prevent | |
954 | * compiler reduction; loop termination via jiffies | |
955 | * is secondary and may or may not happen. | |
956 | */ | |
957 | if (time_after(jiffies, timeout)) | |
958 | break; | |
959 | touch_nmi_watchdog(); | |
960 | } | |
961 | } | |
962 | #else | |
2fa72c8f | 963 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
964 | { |
965 | } | |
966 | #endif | |
967 | ||
3c2a0909 S |
968 | #if defined(CONFIG_PRINTK_CORE_NUM) |
969 | static bool printk_core_num = 1; | |
970 | #else | |
971 | static bool printk_core_num = 0; | |
972 | #endif | |
973 | module_param_named(core_num, printk_core_num, bool, S_IRUGO | S_IWUSR); | |
974 | ||
7ff9554b KS |
975 | #if defined(CONFIG_PRINTK_TIME) |
976 | static bool printk_time = 1; | |
977 | #else | |
978 | static bool printk_time; | |
979 | #endif | |
980 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); | |
981 | ||
084681d1 KS |
982 | static size_t print_time(u64 ts, char *buf) |
983 | { | |
984 | unsigned long rem_nsec; | |
985 | ||
986 | if (!printk_time) | |
987 | return 0; | |
988 | ||
35dac27c RD |
989 | rem_nsec = do_div(ts, 1000000000); |
990 | ||
084681d1 | 991 | if (!buf) |
35dac27c | 992 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 993 | |
084681d1 KS |
994 | return sprintf(buf, "[%5lu.%06lu] ", |
995 | (unsigned long)ts, rem_nsec / 1000); | |
996 | } | |
997 | ||
3ce9a7c0 | 998 | static size_t print_prefix(const struct log *msg, bool syslog, char *buf) |
649e6ee3 | 999 | { |
3ce9a7c0 | 1000 | size_t len = 0; |
43a73a50 | 1001 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 1002 | |
3ce9a7c0 KS |
1003 | if (syslog) { |
1004 | if (buf) { | |
43a73a50 | 1005 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
1006 | } else { |
1007 | len += 3; | |
43a73a50 KS |
1008 | if (prefix > 999) |
1009 | len += 3; | |
1010 | else if (prefix > 99) | |
1011 | len += 2; | |
1012 | else if (prefix > 9) | |
3ce9a7c0 KS |
1013 | len++; |
1014 | } | |
1015 | } | |
649e6ee3 | 1016 | |
084681d1 | 1017 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3c2a0909 S |
1018 | #ifdef CONFIG_PRINTK_PROCESS |
1019 | len += print_process(msg, buf ? buf + len : NULL); | |
1020 | #endif | |
3ce9a7c0 | 1021 | return len; |
649e6ee3 KS |
1022 | } |
1023 | ||
5becfb1d KS |
1024 | static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
1025 | bool syslog, char *buf, size_t size) | |
7ff9554b | 1026 | { |
3ce9a7c0 KS |
1027 | const char *text = log_text(msg); |
1028 | size_t text_size = msg->text_len; | |
5becfb1d KS |
1029 | bool prefix = true; |
1030 | bool newline = true; | |
3ce9a7c0 KS |
1031 | size_t len = 0; |
1032 | ||
5becfb1d KS |
1033 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
1034 | prefix = false; | |
1035 | ||
1036 | if (msg->flags & LOG_CONT) { | |
1037 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) | |
1038 | prefix = false; | |
1039 | ||
1040 | if (!(msg->flags & LOG_NEWLINE)) | |
1041 | newline = false; | |
1042 | } | |
1043 | ||
3ce9a7c0 KS |
1044 | do { |
1045 | const char *next = memchr(text, '\n', text_size); | |
1046 | size_t text_len; | |
1047 | ||
1048 | if (next) { | |
1049 | text_len = next - text; | |
1050 | next++; | |
1051 | text_size -= next - text; | |
1052 | } else { | |
1053 | text_len = text_size; | |
1054 | } | |
7ff9554b | 1055 | |
3ce9a7c0 KS |
1056 | if (buf) { |
1057 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 1058 | text_len + 1 >= size - len) |
3ce9a7c0 | 1059 | break; |
7ff9554b | 1060 | |
5becfb1d KS |
1061 | if (prefix) |
1062 | len += print_prefix(msg, syslog, buf + len); | |
3ce9a7c0 KS |
1063 | memcpy(buf + len, text, text_len); |
1064 | len += text_len; | |
5becfb1d KS |
1065 | if (next || newline) |
1066 | buf[len++] = '\n'; | |
3ce9a7c0 KS |
1067 | } else { |
1068 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5becfb1d KS |
1069 | if (prefix) |
1070 | len += print_prefix(msg, syslog, NULL); | |
1071 | len += text_len; | |
1072 | if (next || newline) | |
1073 | len++; | |
3ce9a7c0 | 1074 | } |
7ff9554b | 1075 | |
5becfb1d | 1076 | prefix = true; |
3ce9a7c0 KS |
1077 | text = next; |
1078 | } while (text); | |
7ff9554b | 1079 | |
7ff9554b KS |
1080 | return len; |
1081 | } | |
1082 | ||
1083 | static int syslog_print(char __user *buf, int size) | |
1084 | { | |
1085 | char *text; | |
3ce9a7c0 | 1086 | struct log *msg; |
116e90b2 | 1087 | int len = 0; |
7ff9554b | 1088 | |
70498253 | 1089 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1090 | if (!text) |
1091 | return -ENOMEM; | |
1092 | ||
116e90b2 JB |
1093 | while (size > 0) { |
1094 | size_t n; | |
eb02dac9 | 1095 | size_t skip; |
116e90b2 JB |
1096 | |
1097 | raw_spin_lock_irq(&logbuf_lock); | |
1098 | if (syslog_seq < log_first_seq) { | |
1099 | /* messages are gone, move to first one */ | |
1100 | syslog_seq = log_first_seq; | |
1101 | syslog_idx = log_first_idx; | |
5becfb1d | 1102 | syslog_prev = 0; |
eb02dac9 | 1103 | syslog_partial = 0; |
116e90b2 JB |
1104 | } |
1105 | if (syslog_seq == log_next_seq) { | |
1106 | raw_spin_unlock_irq(&logbuf_lock); | |
1107 | break; | |
1108 | } | |
eb02dac9 KS |
1109 | |
1110 | skip = syslog_partial; | |
116e90b2 | 1111 | msg = log_from_idx(syslog_idx); |
70498253 KS |
1112 | n = msg_print_text(msg, syslog_prev, true, text, |
1113 | LOG_LINE_MAX + PREFIX_MAX); | |
eb02dac9 KS |
1114 | if (n - syslog_partial <= size) { |
1115 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
1116 | syslog_idx = log_next(syslog_idx); |
1117 | syslog_seq++; | |
5becfb1d | 1118 | syslog_prev = msg->flags; |
eb02dac9 KS |
1119 | n -= syslog_partial; |
1120 | syslog_partial = 0; | |
1121 | } else if (!len){ | |
1122 | /* partial read(), remember position */ | |
1123 | n = size; | |
1124 | syslog_partial += n; | |
116e90b2 JB |
1125 | } else |
1126 | n = 0; | |
1127 | raw_spin_unlock_irq(&logbuf_lock); | |
1128 | ||
1129 | if (!n) | |
1130 | break; | |
1131 | ||
eb02dac9 | 1132 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1133 | if (!len) |
1134 | len = -EFAULT; | |
1135 | break; | |
1136 | } | |
eb02dac9 KS |
1137 | |
1138 | len += n; | |
1139 | size -= n; | |
1140 | buf += n; | |
7ff9554b | 1141 | } |
7ff9554b KS |
1142 | |
1143 | kfree(text); | |
1144 | return len; | |
1145 | } | |
1146 | ||
1147 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1148 | { | |
1149 | char *text; | |
1150 | int len = 0; | |
1151 | ||
70498253 | 1152 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1153 | if (!text) |
1154 | return -ENOMEM; | |
1155 | ||
1156 | raw_spin_lock_irq(&logbuf_lock); | |
1157 | if (buf) { | |
1158 | u64 next_seq; | |
1159 | u64 seq; | |
1160 | u32 idx; | |
5becfb1d | 1161 | enum log_flags prev; |
7ff9554b KS |
1162 | |
1163 | if (clear_seq < log_first_seq) { | |
1164 | /* messages are gone, move to first available one */ | |
1165 | clear_seq = log_first_seq; | |
1166 | clear_idx = log_first_idx; | |
1167 | } | |
1168 | ||
1169 | /* | |
1170 | * Find first record that fits, including all following records, | |
1171 | * into the user-provided buffer for this dump. | |
e2ae715d | 1172 | */ |
7ff9554b KS |
1173 | seq = clear_seq; |
1174 | idx = clear_idx; | |
5becfb1d | 1175 | prev = 0; |
7ff9554b | 1176 | while (seq < log_next_seq) { |
3ce9a7c0 KS |
1177 | struct log *msg = log_from_idx(idx); |
1178 | ||
5becfb1d | 1179 | len += msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1180 | prev = msg->flags; |
7ff9554b KS |
1181 | idx = log_next(idx); |
1182 | seq++; | |
1183 | } | |
e2ae715d KS |
1184 | |
1185 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1186 | seq = clear_seq; |
1187 | idx = clear_idx; | |
5becfb1d | 1188 | prev = 0; |
7ff9554b | 1189 | while (len > size && seq < log_next_seq) { |
3ce9a7c0 KS |
1190 | struct log *msg = log_from_idx(idx); |
1191 | ||
5becfb1d | 1192 | len -= msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1193 | prev = msg->flags; |
7ff9554b KS |
1194 | idx = log_next(idx); |
1195 | seq++; | |
1196 | } | |
1197 | ||
e2ae715d | 1198 | /* last message fitting into this dump */ |
7ff9554b KS |
1199 | next_seq = log_next_seq; |
1200 | ||
1201 | len = 0; | |
1202 | while (len >= 0 && seq < next_seq) { | |
3ce9a7c0 | 1203 | struct log *msg = log_from_idx(idx); |
7ff9554b KS |
1204 | int textlen; |
1205 | ||
70498253 KS |
1206 | textlen = msg_print_text(msg, prev, true, text, |
1207 | LOG_LINE_MAX + PREFIX_MAX); | |
7ff9554b KS |
1208 | if (textlen < 0) { |
1209 | len = textlen; | |
1210 | break; | |
1211 | } | |
1212 | idx = log_next(idx); | |
1213 | seq++; | |
5becfb1d | 1214 | prev = msg->flags; |
7ff9554b KS |
1215 | |
1216 | raw_spin_unlock_irq(&logbuf_lock); | |
1217 | if (copy_to_user(buf + len, text, textlen)) | |
1218 | len = -EFAULT; | |
1219 | else | |
1220 | len += textlen; | |
1221 | raw_spin_lock_irq(&logbuf_lock); | |
1222 | ||
1223 | if (seq < log_first_seq) { | |
1224 | /* messages are gone, move to next one */ | |
1225 | seq = log_first_seq; | |
1226 | idx = log_first_idx; | |
5becfb1d | 1227 | prev = 0; |
7ff9554b KS |
1228 | } |
1229 | } | |
1230 | } | |
1231 | ||
1232 | if (clear) { | |
1233 | clear_seq = log_next_seq; | |
1234 | clear_idx = log_next_idx; | |
1235 | } | |
1236 | raw_spin_unlock_irq(&logbuf_lock); | |
1237 | ||
1238 | kfree(text); | |
1239 | return len; | |
1240 | } | |
1241 | ||
00234592 | 1242 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
1da177e4 | 1243 | { |
7ff9554b KS |
1244 | bool clear = false; |
1245 | static int saved_console_loglevel = -1; | |
ee24aebf | 1246 | int error; |
1da177e4 | 1247 | |
ee24aebf LT |
1248 | error = check_syslog_permissions(type, from_file); |
1249 | if (error) | |
1250 | goto out; | |
12b3052c EP |
1251 | |
1252 | error = security_syslog(type); | |
1da177e4 LT |
1253 | if (error) |
1254 | return error; | |
1255 | ||
1256 | switch (type) { | |
d78ca3cd | 1257 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1258 | break; |
d78ca3cd | 1259 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1260 | break; |
d78ca3cd | 1261 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1262 | error = -EINVAL; |
1263 | if (!buf || len < 0) | |
1264 | goto out; | |
1265 | error = 0; | |
1266 | if (!len) | |
1267 | goto out; | |
1268 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1269 | error = -EFAULT; | |
1270 | goto out; | |
1271 | } | |
40dc5651 | 1272 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1273 | syslog_seq != log_next_seq); |
cb424ffe | 1274 | if (error) |
1da177e4 | 1275 | goto out; |
7ff9554b | 1276 | error = syslog_print(buf, len); |
1da177e4 | 1277 | break; |
d78ca3cd KC |
1278 | /* Read/clear last kernel messages */ |
1279 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1280 | clear = true; |
1da177e4 | 1281 | /* FALL THRU */ |
d78ca3cd KC |
1282 | /* Read last kernel messages */ |
1283 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1284 | error = -EINVAL; |
1285 | if (!buf || len < 0) | |
1286 | goto out; | |
1287 | error = 0; | |
1288 | if (!len) | |
1289 | goto out; | |
1290 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1291 | error = -EFAULT; | |
1292 | goto out; | |
1293 | } | |
7ff9554b | 1294 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1295 | break; |
d78ca3cd KC |
1296 | /* Clear ring buffer */ |
1297 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1298 | syslog_print_all(NULL, 0, true); |
4661e356 | 1299 | break; |
d78ca3cd KC |
1300 | /* Disable logging to console */ |
1301 | case SYSLOG_ACTION_CONSOLE_OFF: | |
1aaad49e FP |
1302 | if (saved_console_loglevel == -1) |
1303 | saved_console_loglevel = console_loglevel; | |
1da177e4 LT |
1304 | console_loglevel = minimum_console_loglevel; |
1305 | break; | |
d78ca3cd KC |
1306 | /* Enable logging to console */ |
1307 | case SYSLOG_ACTION_CONSOLE_ON: | |
1aaad49e FP |
1308 | if (saved_console_loglevel != -1) { |
1309 | console_loglevel = saved_console_loglevel; | |
1310 | saved_console_loglevel = -1; | |
1311 | } | |
1da177e4 | 1312 | break; |
d78ca3cd KC |
1313 | /* Set level of messages printed to console */ |
1314 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1315 | error = -EINVAL; |
1316 | if (len < 1 || len > 8) | |
1317 | goto out; | |
1318 | if (len < minimum_console_loglevel) | |
1319 | len = minimum_console_loglevel; | |
1320 | console_loglevel = len; | |
1aaad49e FP |
1321 | /* Implicitly re-enable logging to console */ |
1322 | saved_console_loglevel = -1; | |
1da177e4 LT |
1323 | error = 0; |
1324 | break; | |
d78ca3cd KC |
1325 | /* Number of chars in the log buffer */ |
1326 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1327 | raw_spin_lock_irq(&logbuf_lock); |
1328 | if (syslog_seq < log_first_seq) { | |
1329 | /* messages are gone, move to first one */ | |
1330 | syslog_seq = log_first_seq; | |
1331 | syslog_idx = log_first_idx; | |
5becfb1d | 1332 | syslog_prev = 0; |
eb02dac9 | 1333 | syslog_partial = 0; |
7ff9554b KS |
1334 | } |
1335 | if (from_file) { | |
1336 | /* | |
1337 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1338 | * for pending data, not the size; return the count of | |
1339 | * records, not the length. | |
1340 | */ | |
1341 | error = log_next_idx - syslog_idx; | |
1342 | } else { | |
5becfb1d KS |
1343 | u64 seq = syslog_seq; |
1344 | u32 idx = syslog_idx; | |
1345 | enum log_flags prev = syslog_prev; | |
7ff9554b KS |
1346 | |
1347 | error = 0; | |
7ff9554b | 1348 | while (seq < log_next_seq) { |
3ce9a7c0 KS |
1349 | struct log *msg = log_from_idx(idx); |
1350 | ||
5becfb1d | 1351 | error += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1352 | idx = log_next(idx); |
1353 | seq++; | |
5becfb1d | 1354 | prev = msg->flags; |
7ff9554b | 1355 | } |
eb02dac9 | 1356 | error -= syslog_partial; |
7ff9554b KS |
1357 | } |
1358 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1359 | break; |
d78ca3cd KC |
1360 | /* Size of the log buffer */ |
1361 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1362 | error = log_buf_len; |
1363 | break; | |
1364 | default: | |
1365 | error = -EINVAL; | |
1366 | break; | |
1367 | } | |
1368 | out: | |
1369 | return error; | |
1370 | } | |
1371 | ||
1e7bfb21 | 1372 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1373 | { |
637241a9 | 1374 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1375 | } |
1376 | ||
1da177e4 LT |
1377 | /* |
1378 | * Call the console drivers, asking them to write out | |
1379 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1380 | * The console_lock must be held. |
1da177e4 | 1381 | */ |
7ff9554b | 1382 | static void call_console_drivers(int level, const char *text, size_t len) |
1da177e4 | 1383 | { |
7ff9554b | 1384 | struct console *con; |
1da177e4 | 1385 | |
9e84145b | 1386 | trace_console_rcuidle(text, len); |
7ff9554b KS |
1387 | |
1388 | if (level >= console_loglevel && !ignore_loglevel) | |
1389 | return; | |
1390 | if (!console_drivers) | |
1391 | return; | |
1392 | ||
1393 | for_each_console(con) { | |
1394 | if (exclusive_console && con != exclusive_console) | |
1395 | continue; | |
1396 | if (!(con->flags & CON_ENABLED)) | |
1397 | continue; | |
1398 | if (!con->write) | |
1399 | continue; | |
1400 | if (!cpu_online(smp_processor_id()) && | |
1401 | !(con->flags & CON_ANYTIME)) | |
1402 | continue; | |
1403 | con->write(con, text, len); | |
1404 | } | |
1da177e4 LT |
1405 | } |
1406 | ||
1407 | /* | |
1408 | * Zap console related locks when oopsing. Only zap at most once | |
1409 | * every 10 seconds, to leave time for slow consoles to print a | |
1410 | * full oops. | |
1411 | */ | |
1412 | static void zap_locks(void) | |
1413 | { | |
1414 | static unsigned long oops_timestamp; | |
1415 | ||
1416 | if (time_after_eq(jiffies, oops_timestamp) && | |
40dc5651 | 1417 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1418 | return; |
1419 | ||
1420 | oops_timestamp = jiffies; | |
1421 | ||
94d24fc4 | 1422 | debug_locks_off(); |
1da177e4 | 1423 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1424 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1425 | /* And make sure that we print immediately */ |
5b8c4f23 | 1426 | sema_init(&console_sem, 1); |
1da177e4 LT |
1427 | } |
1428 | ||
76a8ad29 ME |
1429 | /* Check if we have any console registered that can be called early in boot. */ |
1430 | static int have_callable_console(void) | |
1431 | { | |
1432 | struct console *con; | |
1433 | ||
4d091611 | 1434 | for_each_console(con) |
76a8ad29 ME |
1435 | if (con->flags & CON_ANYTIME) |
1436 | return 1; | |
1437 | ||
1438 | return 0; | |
1439 | } | |
1440 | ||
266c2e0a LT |
1441 | /* |
1442 | * Can we actually use the console at this time on this cpu? | |
1443 | * | |
1444 | * Console drivers may assume that per-cpu resources have | |
1445 | * been allocated. So unless they're explicitly marked as | |
1446 | * being able to cope (CON_ANYTIME) don't call them until | |
1447 | * this CPU is officially up. | |
1448 | */ | |
1449 | static inline int can_use_console(unsigned int cpu) | |
1450 | { | |
1451 | return cpu_online(cpu) || have_callable_console(); | |
1452 | } | |
1453 | ||
1454 | /* | |
1455 | * Try to get console ownership to actually show the kernel | |
1456 | * messages from a 'printk'. Return true (and with the | |
ac751efa | 1457 | * console_lock held, and 'console_locked' set) if it |
266c2e0a LT |
1458 | * is successful, false otherwise. |
1459 | * | |
1460 | * This gets called with the 'logbuf_lock' spinlock held and | |
1461 | * interrupts disabled. It should return with 'lockbuf_lock' | |
1462 | * released but interrupts still disabled. | |
1463 | */ | |
ac751efa | 1464 | static int console_trylock_for_printk(unsigned int cpu) |
8155c02a | 1465 | __releases(&logbuf_lock) |
266c2e0a | 1466 | { |
0b5e1c52 | 1467 | int retval = 0, wake = 0; |
266c2e0a | 1468 | |
ac751efa | 1469 | if (console_trylock()) { |
093a07e2 LT |
1470 | retval = 1; |
1471 | ||
1472 | /* | |
1473 | * If we can't use the console, we need to release | |
1474 | * the console semaphore by hand to avoid flushing | |
1475 | * the buffer. We need to hold the console semaphore | |
1476 | * in order to do this test safely. | |
1477 | */ | |
1478 | if (!can_use_console(cpu)) { | |
1479 | console_locked = 0; | |
0b5e1c52 | 1480 | wake = 1; |
093a07e2 LT |
1481 | retval = 0; |
1482 | } | |
1483 | } | |
7ff9554b | 1484 | logbuf_cpu = UINT_MAX; |
5df5df87 | 1485 | raw_spin_unlock(&logbuf_lock); |
0b5e1c52 PZ |
1486 | if (wake) |
1487 | up(&console_sem); | |
266c2e0a LT |
1488 | return retval; |
1489 | } | |
32a76006 | 1490 | |
af91322e DY |
1491 | int printk_delay_msec __read_mostly; |
1492 | ||
1493 | static inline void printk_delay(void) | |
1494 | { | |
1495 | if (unlikely(printk_delay_msec)) { | |
1496 | int m = printk_delay_msec; | |
1497 | ||
1498 | while (m--) { | |
1499 | mdelay(1); | |
1500 | touch_nmi_watchdog(); | |
1501 | } | |
1502 | } | |
1503 | } | |
1504 | ||
084681d1 KS |
1505 | /* |
1506 | * Continuation lines are buffered, and not committed to the record buffer | |
1507 | * until the line is complete, or a race forces it. The line fragments | |
1508 | * though, are printed immediately to the consoles to ensure everything has | |
1509 | * reached the console in case of a kernel crash. | |
1510 | */ | |
1511 | static struct cont { | |
1512 | char buf[LOG_LINE_MAX]; | |
1513 | size_t len; /* length == 0 means unused buffer */ | |
1514 | size_t cons; /* bytes written to console */ | |
1515 | struct task_struct *owner; /* task of first print*/ | |
1516 | u64 ts_nsec; /* time of first print */ | |
1517 | u8 level; /* log level of first message */ | |
1518 | u8 facility; /* log level of first message */ | |
eab07260 | 1519 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1520 | bool flushed:1; /* buffer sealed and committed */ |
1521 | } cont; | |
1522 | ||
70498253 | 1523 | static void cont_flush(enum log_flags flags) |
084681d1 KS |
1524 | { |
1525 | if (cont.flushed) | |
1526 | return; | |
1527 | if (cont.len == 0) | |
1528 | return; | |
1529 | ||
eab07260 KS |
1530 | if (cont.cons) { |
1531 | /* | |
1532 | * If a fragment of this line was directly flushed to the | |
1533 | * console; wait for the console to pick up the rest of the | |
1534 | * line. LOG_NOCONS suppresses a duplicated output. | |
1535 | */ | |
1536 | log_store(cont.facility, cont.level, flags | LOG_NOCONS, | |
1537 | cont.ts_nsec, NULL, 0, cont.buf, cont.len); | |
1538 | cont.flags = flags; | |
1539 | cont.flushed = true; | |
1540 | } else { | |
1541 | /* | |
1542 | * If no fragment of this line ever reached the console, | |
1543 | * just submit it to the store and free the buffer. | |
1544 | */ | |
1545 | log_store(cont.facility, cont.level, flags, 0, | |
1546 | NULL, 0, cont.buf, cont.len); | |
1547 | cont.len = 0; | |
1548 | } | |
084681d1 KS |
1549 | } |
1550 | ||
1551 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1552 | { | |
1553 | if (cont.len && cont.flushed) | |
1554 | return false; | |
1555 | ||
1556 | if (cont.len + len > sizeof(cont.buf)) { | |
70498253 KS |
1557 | /* the line gets too long, split it up in separate records */ |
1558 | cont_flush(LOG_CONT); | |
084681d1 KS |
1559 | return false; |
1560 | } | |
1561 | ||
1562 | if (!cont.len) { | |
1563 | cont.facility = facility; | |
1564 | cont.level = level; | |
1565 | cont.owner = current; | |
1566 | cont.ts_nsec = local_clock(); | |
eab07260 | 1567 | cont.flags = 0; |
084681d1 KS |
1568 | cont.cons = 0; |
1569 | cont.flushed = false; | |
1570 | } | |
1571 | ||
1572 | memcpy(cont.buf + cont.len, text, len); | |
1573 | cont.len += len; | |
eab07260 KS |
1574 | |
1575 | if (cont.len > (sizeof(cont.buf) * 80) / 100) | |
1576 | cont_flush(LOG_CONT); | |
1577 | ||
084681d1 KS |
1578 | return true; |
1579 | } | |
1580 | ||
1581 | static size_t cont_print_text(char *text, size_t size) | |
1582 | { | |
1583 | size_t textlen = 0; | |
1584 | size_t len; | |
1585 | ||
eab07260 | 1586 | if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { |
084681d1 | 1587 | textlen += print_time(cont.ts_nsec, text); |
3c2a0909 S |
1588 | #ifdef CONFIG_PRINTK_PROCESS |
1589 | *(text+textlen) = ' '; | |
1590 | textlen += print_process(NULL, NULL); | |
1591 | #endif | |
084681d1 KS |
1592 | size -= textlen; |
1593 | } | |
1594 | ||
1595 | len = cont.len - cont.cons; | |
1596 | if (len > 0) { | |
1597 | if (len+1 > size) | |
1598 | len = size-1; | |
1599 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1600 | textlen += len; | |
1601 | cont.cons = cont.len; | |
1602 | } | |
1603 | ||
1604 | if (cont.flushed) { | |
eab07260 KS |
1605 | if (cont.flags & LOG_NEWLINE) |
1606 | text[textlen++] = '\n'; | |
084681d1 KS |
1607 | /* got everything, release buffer */ |
1608 | cont.len = 0; | |
1609 | } | |
1610 | return textlen; | |
1611 | } | |
1612 | ||
7ff9554b KS |
1613 | asmlinkage int vprintk_emit(int facility, int level, |
1614 | const char *dict, size_t dictlen, | |
1615 | const char *fmt, va_list args) | |
1da177e4 | 1616 | { |
7ff9554b | 1617 | static int recursion_bug; |
7ff9554b KS |
1618 | static char textbuf[LOG_LINE_MAX]; |
1619 | char *text = textbuf; | |
c313af14 | 1620 | size_t text_len; |
5becfb1d | 1621 | enum log_flags lflags = 0; |
ac60ad74 | 1622 | unsigned long flags; |
32a76006 | 1623 | int this_cpu; |
7ff9554b | 1624 | int printed_len = 0; |
3c2a0909 | 1625 | static bool prev_new_line = true; |
1da177e4 | 1626 | |
2fa72c8f | 1627 | boot_delay_msec(level); |
af91322e | 1628 | printk_delay(); |
bfe8df3d | 1629 | |
1da177e4 | 1630 | /* This stops the holder of console_sem just where we want him */ |
1a9a8aef | 1631 | local_irq_save(flags); |
32a76006 IM |
1632 | this_cpu = smp_processor_id(); |
1633 | ||
1634 | /* | |
1635 | * Ouch, printk recursed into itself! | |
1636 | */ | |
7ff9554b | 1637 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1638 | /* |
1639 | * If a crash is occurring during printk() on this CPU, | |
1640 | * then try to get the crash message out but make sure | |
1641 | * we can't deadlock. Otherwise just return to avoid the | |
1642 | * recursion and return - but flag the recursion so that | |
1643 | * it can be printed at the next appropriate moment: | |
1644 | */ | |
94d24fc4 | 1645 | if (!oops_in_progress && !lockdep_recursing(current)) { |
3b8945e8 | 1646 | recursion_bug = 1; |
32a76006 IM |
1647 | goto out_restore_irqs; |
1648 | } | |
1649 | zap_locks(); | |
1650 | } | |
1651 | ||
a0f1ccfd | 1652 | lockdep_off(); |
07354eb1 | 1653 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1654 | logbuf_cpu = this_cpu; |
1da177e4 | 1655 | |
3b8945e8 | 1656 | if (recursion_bug) { |
7ff9554b KS |
1657 | static const char recursion_msg[] = |
1658 | "BUG: recent printk recursion!"; | |
1659 | ||
3b8945e8 | 1660 | recursion_bug = 0; |
7ff9554b KS |
1661 | printed_len += strlen(recursion_msg); |
1662 | /* emit KERN_CRIT message */ | |
5becfb1d | 1663 | log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
084681d1 | 1664 | NULL, 0, recursion_msg, printed_len); |
32a76006 | 1665 | } |
1da177e4 | 1666 | |
7ff9554b KS |
1667 | /* |
1668 | * The printf needs to come first; we need the syslog | |
1669 | * prefix which might be passed-in as a parameter. | |
1670 | */ | |
3c2a0909 S |
1671 | if (printk_core_num && prev_new_line) { |
1672 | char tempbuf[LOG_LINE_MAX]; | |
1673 | char *temp = tempbuf; | |
1674 | ||
1675 | vscnprintf(temp, sizeof(tempbuf), fmt, args); | |
1676 | if (printk_get_level(tempbuf)) | |
1677 | text_len = snprintf(text, sizeof(textbuf), | |
1678 | "%c%c[c%d] %s", tempbuf[0], | |
1679 | tempbuf[1], this_cpu, &tempbuf[2]); | |
1680 | else | |
1681 | text_len = snprintf(text, sizeof(textbuf), "[c%d] %s", | |
1682 | this_cpu, &tempbuf[0]); | |
1683 | } else { | |
1684 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); | |
1685 | } | |
1686 | ||
1687 | #ifdef CONFIG_DEBUG_LL | |
1688 | printascii(text); | |
1689 | #endif | |
5fd29d6c | 1690 | |
7ff9554b | 1691 | /* mark and strip a trailing newline */ |
c313af14 KS |
1692 | if (text_len && text[text_len-1] == '\n') { |
1693 | text_len--; | |
5becfb1d | 1694 | lflags |= LOG_NEWLINE; |
3c2a0909 S |
1695 | prev_new_line = true; |
1696 | } else { | |
1697 | prev_new_line = false; | |
7ff9554b | 1698 | } |
9d90c8d9 | 1699 | |
088a52aa JP |
1700 | /* strip kernel syslog prefix and extract log level or control flags */ |
1701 | if (facility == 0) { | |
1702 | int kern_level = printk_get_level(text); | |
1703 | ||
1704 | if (kern_level) { | |
1705 | const char *end_of_header = printk_skip_level(text); | |
1706 | switch (kern_level) { | |
1707 | case '0' ... '7': | |
1708 | if (level == -1) | |
1709 | level = kern_level - '0'; | |
1710 | case 'd': /* KERN_DEFAULT */ | |
1711 | lflags |= LOG_PREFIX; | |
1712 | case 'c': /* KERN_CONT */ | |
1713 | break; | |
1714 | } | |
1715 | text_len -= end_of_header - text; | |
1716 | text = (char *)end_of_header; | |
5fd29d6c LT |
1717 | } |
1718 | } | |
1719 | ||
3c2a0909 S |
1720 | #ifdef CONFIG_EARLY_PRINTK_DIRECT |
1721 | printascii(text); | |
1722 | #endif | |
1723 | ||
c313af14 KS |
1724 | if (level == -1) |
1725 | level = default_message_loglevel; | |
9d90c8d9 | 1726 | |
5becfb1d KS |
1727 | if (dict) |
1728 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1729 | |
5becfb1d | 1730 | if (!(lflags & LOG_NEWLINE)) { |
084681d1 KS |
1731 | /* |
1732 | * Flush the conflicting buffer. An earlier newline was missing, | |
1733 | * or another task also prints continuation lines. | |
1734 | */ | |
5becfb1d | 1735 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
eab07260 | 1736 | cont_flush(LOG_NEWLINE); |
c313af14 | 1737 | |
084681d1 KS |
1738 | /* buffer line if possible, otherwise store it right away */ |
1739 | if (!cont_add(facility, level, text, text_len)) | |
5becfb1d | 1740 | log_store(facility, level, lflags | LOG_CONT, 0, |
084681d1 | 1741 | dict, dictlen, text, text_len); |
5c5d5ca5 | 1742 | } else { |
084681d1 | 1743 | bool stored = false; |
c313af14 | 1744 | |
084681d1 | 1745 | /* |
d3620822 SR |
1746 | * If an earlier newline was missing and it was the same task, |
1747 | * either merge it with the current buffer and flush, or if | |
1748 | * there was a race with interrupts (prefix == true) then just | |
1749 | * flush it out and store this line separately. | |
084681d1 | 1750 | */ |
084681d1 | 1751 | if (cont.len && cont.owner == current) { |
5becfb1d | 1752 | if (!(lflags & LOG_PREFIX)) |
d3620822 | 1753 | stored = cont_add(facility, level, text, text_len); |
eab07260 | 1754 | cont_flush(LOG_NEWLINE); |
c313af14 | 1755 | } |
084681d1 KS |
1756 | |
1757 | if (!stored) | |
5becfb1d | 1758 | log_store(facility, level, lflags, 0, |
084681d1 | 1759 | dict, dictlen, text, text_len); |
1da177e4 | 1760 | } |
084681d1 | 1761 | printed_len += text_len; |
1da177e4 | 1762 | |
266c2e0a | 1763 | /* |
7ff9554b KS |
1764 | * Try to acquire and then immediately release the console semaphore. |
1765 | * The release will print out buffers and wake up /dev/kmsg and syslog() | |
1766 | * users. | |
266c2e0a | 1767 | * |
7ff9554b KS |
1768 | * The console_trylock_for_printk() function will release 'logbuf_lock' |
1769 | * regardless of whether it actually gets the console semaphore or not. | |
266c2e0a | 1770 | */ |
ac751efa TH |
1771 | if (console_trylock_for_printk(this_cpu)) |
1772 | console_unlock(); | |
76a8ad29 | 1773 | |
266c2e0a | 1774 | lockdep_on(); |
32a76006 | 1775 | out_restore_irqs: |
1a9a8aef | 1776 | local_irq_restore(flags); |
76a8ad29 | 1777 | |
1da177e4 LT |
1778 | return printed_len; |
1779 | } | |
7ff9554b KS |
1780 | EXPORT_SYMBOL(vprintk_emit); |
1781 | ||
1782 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1783 | { | |
1784 | return vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1785 | } | |
1da177e4 LT |
1786 | EXPORT_SYMBOL(vprintk); |
1787 | ||
7ff9554b KS |
1788 | asmlinkage int printk_emit(int facility, int level, |
1789 | const char *dict, size_t dictlen, | |
1790 | const char *fmt, ...) | |
1791 | { | |
1792 | va_list args; | |
1793 | int r; | |
1794 | ||
1795 | va_start(args, fmt); | |
1796 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1797 | va_end(args); | |
1798 | ||
1799 | return r; | |
1800 | } | |
1801 | EXPORT_SYMBOL(printk_emit); | |
1802 | ||
1803 | /** | |
1804 | * printk - print a kernel message | |
1805 | * @fmt: format string | |
1806 | * | |
1807 | * This is printk(). It can be called from any context. We want it to work. | |
1808 | * | |
1809 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1810 | * output and call the console drivers. If we fail to get the semaphore, we | |
1811 | * place the output into the log buffer and return. The current holder of | |
1812 | * the console_sem will notice the new output in console_unlock(); and will | |
1813 | * send it to the consoles before releasing the lock. | |
1814 | * | |
1815 | * One effect of this deferred printing is that code which calls printk() and | |
1816 | * then changes console_loglevel may break. This is because console_loglevel | |
1817 | * is inspected when the actual printing occurs. | |
1818 | * | |
1819 | * See also: | |
1820 | * printf(3) | |
1821 | * | |
1822 | * See the vsnprintf() documentation for format string extensions over C99. | |
1823 | */ | |
1824 | asmlinkage int printk(const char *fmt, ...) | |
1825 | { | |
1826 | va_list args; | |
1827 | int r; | |
1828 | ||
1829 | #ifdef CONFIG_KGDB_KDB | |
1830 | if (unlikely(kdb_trap_printk)) { | |
1831 | va_start(args, fmt); | |
1832 | r = vkdb_printf(fmt, args); | |
1833 | va_end(args); | |
1834 | return r; | |
1835 | } | |
1836 | #endif | |
1837 | va_start(args, fmt); | |
1838 | r = vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1839 | va_end(args); | |
1840 | ||
1841 | return r; | |
1842 | } | |
1843 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1844 | |
96efedf1 | 1845 | #else /* CONFIG_PRINTK */ |
d59745ce | 1846 | |
70498253 KS |
1847 | #define LOG_LINE_MAX 0 |
1848 | #define PREFIX_MAX 0 | |
7f3a781d | 1849 | #define LOG_LINE_MAX 0 |
96efedf1 KS |
1850 | static u64 syslog_seq; |
1851 | static u32 syslog_idx; | |
eab07260 KS |
1852 | static u64 console_seq; |
1853 | static u32 console_idx; | |
96efedf1 KS |
1854 | static enum log_flags syslog_prev; |
1855 | static u64 log_first_seq; | |
1856 | static u32 log_first_idx; | |
1857 | static u64 log_next_seq; | |
eab07260 | 1858 | static enum log_flags console_prev; |
084681d1 KS |
1859 | static struct cont { |
1860 | size_t len; | |
1861 | size_t cons; | |
1862 | u8 level; | |
1863 | bool flushed:1; | |
1864 | } cont; | |
7f3a781d KS |
1865 | static struct log *log_from_idx(u32 idx) { return NULL; } |
1866 | static u32 log_next(u32 idx) { return 0; } | |
7f3a781d | 1867 | static void call_console_drivers(int level, const char *text, size_t len) {} |
5becfb1d KS |
1868 | static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
1869 | bool syslog, char *buf, size_t size) { return 0; } | |
084681d1 | 1870 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1871 | |
7f3a781d | 1872 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1873 | |
d0380e6c TG |
1874 | #ifdef CONFIG_EARLY_PRINTK |
1875 | struct console *early_console; | |
1876 | ||
1877 | void early_vprintk(const char *fmt, va_list ap) | |
1878 | { | |
1879 | if (early_console) { | |
1880 | char buf[512]; | |
1881 | int n = vscnprintf(buf, sizeof(buf), fmt, ap); | |
1882 | ||
1883 | early_console->write(early_console, buf, n); | |
1884 | } | |
1885 | } | |
1886 | ||
1887 | asmlinkage void early_printk(const char *fmt, ...) | |
1888 | { | |
1889 | va_list ap; | |
1890 | ||
1891 | va_start(ap, fmt); | |
1892 | early_vprintk(fmt, ap); | |
1893 | va_end(ap); | |
1894 | } | |
1895 | #endif | |
1896 | ||
f7511d5f ST |
1897 | static int __add_preferred_console(char *name, int idx, char *options, |
1898 | char *brl_options) | |
1899 | { | |
1900 | struct console_cmdline *c; | |
1901 | int i; | |
1902 | ||
1903 | /* | |
1904 | * See if this tty is not yet registered, and | |
1905 | * if we have a slot free. | |
1906 | */ | |
1907 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
1908 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
1909 | console_cmdline[i].index == idx) { | |
1910 | if (!brl_options) | |
1911 | selected_console = i; | |
1912 | return 0; | |
1913 | } | |
1914 | if (i == MAX_CMDLINECONSOLES) | |
1915 | return -E2BIG; | |
1916 | if (!brl_options) | |
1917 | selected_console = i; | |
1918 | c = &console_cmdline[i]; | |
1919 | strlcpy(c->name, name, sizeof(c->name)); | |
1920 | c->options = options; | |
1921 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE | |
1922 | c->brl_options = brl_options; | |
1923 | #endif | |
1924 | c->index = idx; | |
1925 | return 0; | |
1926 | } | |
2ea1c539 JB |
1927 | /* |
1928 | * Set up a list of consoles. Called from init/main.c | |
1929 | */ | |
1930 | static int __init console_setup(char *str) | |
1931 | { | |
eaa944af | 1932 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
f7511d5f | 1933 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1934 | int idx; |
1935 | ||
f7511d5f ST |
1936 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1937 | if (!memcmp(str, "brl,", 4)) { | |
1938 | brl_options = ""; | |
1939 | str += 4; | |
1940 | } else if (!memcmp(str, "brl=", 4)) { | |
1941 | brl_options = str + 4; | |
1942 | str = strchr(brl_options, ','); | |
1943 | if (!str) { | |
1944 | printk(KERN_ERR "need port name after brl=\n"); | |
1945 | return 1; | |
1946 | } | |
1947 | *(str++) = 0; | |
1948 | } | |
1949 | #endif | |
1950 | ||
2ea1c539 JB |
1951 | /* |
1952 | * Decode str into name, index, options. | |
1953 | */ | |
1954 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1955 | strcpy(buf, "ttyS"); |
1956 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1957 | } else { |
eaa944af | 1958 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1959 | } |
eaa944af | 1960 | buf[sizeof(buf) - 1] = 0; |
2ea1c539 JB |
1961 | if ((options = strchr(str, ',')) != NULL) |
1962 | *(options++) = 0; | |
1963 | #ifdef __sparc__ | |
1964 | if (!strcmp(str, "ttya")) | |
eaa944af | 1965 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1966 | if (!strcmp(str, "ttyb")) |
eaa944af | 1967 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1968 | #endif |
eaa944af | 1969 | for (s = buf; *s; s++) |
2ea1c539 JB |
1970 | if ((*s >= '0' && *s <= '9') || *s == ',') |
1971 | break; | |
1972 | idx = simple_strtoul(s, NULL, 10); | |
1973 | *s = 0; | |
1974 | ||
f7511d5f | 1975 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1976 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1977 | return 1; |
1978 | } | |
1979 | __setup("console=", console_setup); | |
1980 | ||
3c0547ba MM |
1981 | /** |
1982 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1983 | * @name: device name |
1984 | * @idx: device index | |
1985 | * @options: options for this console | |
3c0547ba MM |
1986 | * |
1987 | * The last preferred console added will be used for kernel messages | |
1988 | * and stdin/out/err for init. Normally this is used by console_setup | |
1989 | * above to handle user-supplied console arguments; however it can also | |
1990 | * be used by arch-specific code either to override the user or more | |
1991 | * commonly to provide a default console (ie from PROM variables) when | |
1992 | * the user has not supplied one. | |
1993 | */ | |
fb445ee5 | 1994 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 1995 | { |
f7511d5f | 1996 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
1997 | } |
1998 | ||
b6b1d877 | 1999 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
18a8bd94 YL |
2000 | { |
2001 | struct console_cmdline *c; | |
2002 | int i; | |
2003 | ||
2004 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
2005 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
2006 | console_cmdline[i].index == idx) { | |
2007 | c = &console_cmdline[i]; | |
f735295b | 2008 | strlcpy(c->name, name_new, sizeof(c->name)); |
18a8bd94 YL |
2009 | c->name[sizeof(c->name) - 1] = 0; |
2010 | c->options = options; | |
2011 | c->index = idx_new; | |
2012 | return i; | |
2013 | } | |
2014 | /* not found */ | |
2015 | return -1; | |
2016 | } | |
2017 | ||
2329abfa | 2018 | bool console_suspend_enabled = 1; |
8f4ce8c3 AS |
2019 | EXPORT_SYMBOL(console_suspend_enabled); |
2020 | ||
2021 | static int __init console_suspend_disable(char *str) | |
2022 | { | |
2023 | console_suspend_enabled = 0; | |
2024 | return 1; | |
2025 | } | |
2026 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
2027 | module_param_named(console_suspend, console_suspend_enabled, |
2028 | bool, S_IRUGO | S_IWUSR); | |
2029 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
2030 | " and hibernate operations"); | |
8f4ce8c3 | 2031 | |
557240b4 LT |
2032 | /** |
2033 | * suspend_console - suspend the console subsystem | |
2034 | * | |
2035 | * This disables printk() while we go into suspend states | |
2036 | */ | |
2037 | void suspend_console(void) | |
2038 | { | |
8f4ce8c3 AS |
2039 | if (!console_suspend_enabled) |
2040 | return; | |
0d63081d | 2041 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 2042 | console_lock(); |
557240b4 | 2043 | console_suspended = 1; |
403f3075 | 2044 | up(&console_sem); |
557240b4 LT |
2045 | } |
2046 | ||
2047 | void resume_console(void) | |
2048 | { | |
8f4ce8c3 AS |
2049 | if (!console_suspend_enabled) |
2050 | return; | |
403f3075 | 2051 | down(&console_sem); |
557240b4 | 2052 | console_suspended = 0; |
ac751efa | 2053 | console_unlock(); |
557240b4 LT |
2054 | } |
2055 | ||
3c2a0909 S |
2056 | /** |
2057 | * console_flush - flush dmesg if console isn't suspended | |
2058 | * console_unlock always flushes the dmesg buffer, so just try to | |
2059 | * grab&drop the console lock. If that fails we know that the current | |
2060 | * holder will eventually drop the console lock and so flush the dmesg | |
2061 | * buffers at the earliest possible time. | |
2062 | */ | |
2063 | void console_flush(void) | |
2064 | { | |
2065 | if (console_trylock()) | |
2066 | console_unlock(); | |
2067 | } | |
2068 | ||
034260d6 KC |
2069 | /** |
2070 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
2071 | * @self: notifier struct | |
2072 | * @action: CPU hotplug event | |
2073 | * @hcpu: unused | |
2074 | * | |
2075 | * If printk() is called from a CPU that is not online yet, the messages | |
2076 | * will be spooled but will not show up on the console. This function is | |
2077 | * called when a new CPU comes online (or fails to come up), and ensures | |
2078 | * that any such output gets printed. | |
2079 | */ | |
2080 | static int __cpuinit console_cpu_notify(struct notifier_block *self, | |
2081 | unsigned long action, void *hcpu) | |
2082 | { | |
2083 | switch (action) { | |
2084 | case CPU_ONLINE: | |
2085 | case CPU_DEAD: | |
034260d6 KC |
2086 | case CPU_DOWN_FAILED: |
2087 | case CPU_UP_CANCELED: | |
3c2a0909 | 2088 | console_flush(); |
034260d6 KC |
2089 | } |
2090 | return NOTIFY_OK; | |
2091 | } | |
2092 | ||
1da177e4 | 2093 | /** |
ac751efa | 2094 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 2095 | * |
ac751efa | 2096 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
2097 | * exclusive access to the console system and the console_drivers list. |
2098 | * | |
2099 | * Can sleep, returns nothing. | |
2100 | */ | |
ac751efa | 2101 | void console_lock(void) |
1da177e4 | 2102 | { |
6b898c07 DV |
2103 | might_sleep(); |
2104 | ||
1da177e4 | 2105 | down(&console_sem); |
403f3075 AH |
2106 | if (console_suspended) |
2107 | return; | |
1da177e4 LT |
2108 | console_locked = 1; |
2109 | console_may_schedule = 1; | |
daee7797 | 2110 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); |
1da177e4 | 2111 | } |
ac751efa | 2112 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 2113 | |
ac751efa TH |
2114 | /** |
2115 | * console_trylock - try to lock the console system for exclusive use. | |
2116 | * | |
2117 | * Tried to acquire a lock which guarantees that the caller has | |
2118 | * exclusive access to the console system and the console_drivers list. | |
2119 | * | |
2120 | * returns 1 on success, and 0 on failure to acquire the lock. | |
2121 | */ | |
2122 | int console_trylock(void) | |
1da177e4 LT |
2123 | { |
2124 | if (down_trylock(&console_sem)) | |
ac751efa | 2125 | return 0; |
403f3075 AH |
2126 | if (console_suspended) { |
2127 | up(&console_sem); | |
ac751efa | 2128 | return 0; |
403f3075 | 2129 | } |
1da177e4 LT |
2130 | console_locked = 1; |
2131 | console_may_schedule = 0; | |
daee7797 | 2132 | mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_); |
ac751efa | 2133 | return 1; |
1da177e4 | 2134 | } |
ac751efa | 2135 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
2136 | |
2137 | int is_console_locked(void) | |
2138 | { | |
2139 | return console_locked; | |
2140 | } | |
1da177e4 | 2141 | |
eab07260 KS |
2142 | static void console_cont_flush(char *text, size_t size) |
2143 | { | |
2144 | unsigned long flags; | |
2145 | size_t len; | |
2146 | ||
2147 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2148 | ||
2149 | if (!cont.len) | |
2150 | goto out; | |
2151 | ||
2152 | /* | |
2153 | * We still queue earlier records, likely because the console was | |
2154 | * busy. The earlier ones need to be printed before this one, we | |
2155 | * did not flush any fragment so far, so just let it queue up. | |
2156 | */ | |
2157 | if (console_seq < log_next_seq && !cont.cons) | |
2158 | goto out; | |
2159 | ||
2160 | len = cont_print_text(text, size); | |
2161 | raw_spin_unlock(&logbuf_lock); | |
2162 | stop_critical_timings(); | |
2163 | call_console_drivers(cont.level, text, len); | |
2164 | start_critical_timings(); | |
2165 | local_irq_restore(flags); | |
2166 | return; | |
2167 | out: | |
2168 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2169 | } | |
7ff9554b | 2170 | |
1da177e4 | 2171 | /** |
ac751efa | 2172 | * console_unlock - unlock the console system |
1da177e4 | 2173 | * |
ac751efa | 2174 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
2175 | * and the console driver list. |
2176 | * | |
ac751efa TH |
2177 | * While the console_lock was held, console output may have been buffered |
2178 | * by printk(). If this is the case, console_unlock(); emits | |
2179 | * the output prior to releasing the lock. | |
1da177e4 | 2180 | * |
7f3a781d | 2181 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2182 | * |
ac751efa | 2183 | * console_unlock(); may be called from any context. |
1da177e4 | 2184 | */ |
ac751efa | 2185 | void console_unlock(void) |
1da177e4 | 2186 | { |
70498253 | 2187 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2188 | static u64 seen_seq; |
1da177e4 | 2189 | unsigned long flags; |
7ff9554b | 2190 | bool wake_klogd = false; |
f7184747 | 2191 | bool do_cond_resched, retry; |
1da177e4 | 2192 | |
557240b4 | 2193 | if (console_suspended) { |
403f3075 | 2194 | up(&console_sem); |
557240b4 LT |
2195 | return; |
2196 | } | |
78944e54 | 2197 | |
f7184747 TH |
2198 | /* |
2199 | * Console drivers are called under logbuf_lock, so | |
2200 | * @console_may_schedule should be cleared before; however, we may | |
2201 | * end up dumping a lot of lines, for example, if called from | |
2202 | * console registration path, and should invoke cond_resched() | |
2203 | * between lines if allowable. Not doing so can cause a very long | |
2204 | * scheduling stall on a slow console leading to RCU stall and | |
2205 | * softlockup warnings which exacerbate the issue with more | |
2206 | * messages practically incapacitating the system. | |
2207 | */ | |
2208 | do_cond_resched = console_may_schedule; | |
78944e54 AD |
2209 | console_may_schedule = 0; |
2210 | ||
084681d1 | 2211 | /* flush buffered message fragment immediately to console */ |
eab07260 | 2212 | console_cont_flush(text, sizeof(text)); |
4f2a8d3c | 2213 | again: |
7ff9554b KS |
2214 | for (;;) { |
2215 | struct log *msg; | |
3ce9a7c0 | 2216 | size_t len; |
7ff9554b KS |
2217 | int level; |
2218 | ||
07354eb1 | 2219 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2220 | if (seen_seq != log_next_seq) { |
2221 | wake_klogd = true; | |
2222 | seen_seq = log_next_seq; | |
2223 | } | |
2224 | ||
2225 | if (console_seq < log_first_seq) { | |
2226 | /* messages are gone, move to first one */ | |
2227 | console_seq = log_first_seq; | |
2228 | console_idx = log_first_idx; | |
5becfb1d | 2229 | console_prev = 0; |
7ff9554b | 2230 | } |
084681d1 | 2231 | skip: |
7ff9554b KS |
2232 | if (console_seq == log_next_seq) |
2233 | break; | |
2234 | ||
2235 | msg = log_from_idx(console_idx); | |
084681d1 KS |
2236 | if (msg->flags & LOG_NOCONS) { |
2237 | /* | |
2238 | * Skip record we have buffered and already printed | |
2239 | * directly to the console when we received it. | |
2240 | */ | |
2241 | console_idx = log_next(console_idx); | |
2242 | console_seq++; | |
68b6507d KS |
2243 | /* |
2244 | * We will get here again when we register a new | |
2245 | * CON_PRINTBUFFER console. Clear the flag so we | |
2246 | * will properly dump everything later. | |
2247 | */ | |
2248 | msg->flags &= ~LOG_NOCONS; | |
eab07260 | 2249 | console_prev = msg->flags; |
084681d1 KS |
2250 | goto skip; |
2251 | } | |
649e6ee3 | 2252 | |
084681d1 | 2253 | level = msg->level; |
5becfb1d KS |
2254 | len = msg_print_text(msg, console_prev, false, |
2255 | text, sizeof(text)); | |
7ff9554b KS |
2256 | console_idx = log_next(console_idx); |
2257 | console_seq++; | |
5becfb1d | 2258 | console_prev = msg->flags; |
07354eb1 | 2259 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2260 | |
81d68a96 | 2261 | stop_critical_timings(); /* don't trace print latency */ |
7ff9554b | 2262 | call_console_drivers(level, text, len); |
81d68a96 | 2263 | start_critical_timings(); |
1da177e4 | 2264 | local_irq_restore(flags); |
f7184747 TH |
2265 | |
2266 | if (do_cond_resched) | |
2267 | cond_resched(); | |
1da177e4 LT |
2268 | } |
2269 | console_locked = 0; | |
daee7797 | 2270 | mutex_release(&console_lock_dep_map, 1, _RET_IP_); |
fe3d8ad3 FT |
2271 | |
2272 | /* Release the exclusive_console once it is used */ | |
2273 | if (unlikely(exclusive_console)) | |
2274 | exclusive_console = NULL; | |
2275 | ||
07354eb1 | 2276 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2277 | |
0b5e1c52 | 2278 | up(&console_sem); |
4f2a8d3c PZ |
2279 | |
2280 | /* | |
2281 | * Someone could have filled up the buffer again, so re-check if there's | |
2282 | * something to flush. In case we cannot trylock the console_sem again, | |
2283 | * there's a new owner and the console_unlock() from them will do the | |
2284 | * flush, no worries. | |
2285 | */ | |
07354eb1 | 2286 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2287 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2288 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2289 | ||
4f2a8d3c PZ |
2290 | if (retry && console_trylock()) |
2291 | goto again; | |
2292 | ||
e3e8a75d KK |
2293 | if (wake_klogd) |
2294 | wake_up_klogd(); | |
1da177e4 | 2295 | } |
ac751efa | 2296 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2297 | |
ddad86c2 MW |
2298 | /** |
2299 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2300 | * |
2301 | * If the console code is currently allowed to sleep, and | |
2302 | * if this CPU should yield the CPU to another task, do | |
2303 | * so here. | |
2304 | * | |
ac751efa | 2305 | * Must be called within console_lock();. |
1da177e4 LT |
2306 | */ |
2307 | void __sched console_conditional_schedule(void) | |
2308 | { | |
2309 | if (console_may_schedule) | |
2310 | cond_resched(); | |
2311 | } | |
2312 | EXPORT_SYMBOL(console_conditional_schedule); | |
2313 | ||
1da177e4 LT |
2314 | void console_unblank(void) |
2315 | { | |
2316 | struct console *c; | |
2317 | ||
2318 | /* | |
2319 | * console_unblank can no longer be called in interrupt context unless | |
2320 | * oops_in_progress is set to 1.. | |
2321 | */ | |
2322 | if (oops_in_progress) { | |
2323 | if (down_trylock(&console_sem) != 0) | |
2324 | return; | |
2325 | } else | |
ac751efa | 2326 | console_lock(); |
1da177e4 LT |
2327 | |
2328 | console_locked = 1; | |
2329 | console_may_schedule = 0; | |
4d091611 | 2330 | for_each_console(c) |
1da177e4 LT |
2331 | if ((c->flags & CON_ENABLED) && c->unblank) |
2332 | c->unblank(); | |
ac751efa | 2333 | console_unlock(); |
1da177e4 | 2334 | } |
1da177e4 | 2335 | |
f7184747 TH |
2336 | /** |
2337 | * console_flush_on_panic - flush console content on panic | |
2338 | * | |
2339 | * Immediately output all pending messages no matter what. | |
2340 | */ | |
2341 | void console_flush_on_panic(void) | |
2342 | { | |
2343 | /* | |
2344 | * If someone else is holding the console lock, trylock will fail | |
2345 | * and may_schedule may be set. Ignore and proceed to unlock so | |
2346 | * that messages are flushed out. As this can be called from any | |
2347 | * context and we don't want to get preempted while flushing, | |
2348 | * ensure may_schedule is cleared. | |
2349 | */ | |
2350 | console_trylock(); | |
2351 | console_may_schedule = 0; | |
2352 | console_unlock(); | |
2353 | } | |
2354 | ||
1da177e4 LT |
2355 | /* |
2356 | * Return the console tty driver structure and its associated index | |
2357 | */ | |
2358 | struct tty_driver *console_device(int *index) | |
2359 | { | |
2360 | struct console *c; | |
2361 | struct tty_driver *driver = NULL; | |
2362 | ||
ac751efa | 2363 | console_lock(); |
4d091611 | 2364 | for_each_console(c) { |
1da177e4 LT |
2365 | if (!c->device) |
2366 | continue; | |
2367 | driver = c->device(c, index); | |
2368 | if (driver) | |
2369 | break; | |
2370 | } | |
ac751efa | 2371 | console_unlock(); |
1da177e4 LT |
2372 | return driver; |
2373 | } | |
2374 | ||
2375 | /* | |
2376 | * Prevent further output on the passed console device so that (for example) | |
2377 | * serial drivers can disable console output before suspending a port, and can | |
2378 | * re-enable output afterwards. | |
2379 | */ | |
2380 | void console_stop(struct console *console) | |
2381 | { | |
ac751efa | 2382 | console_lock(); |
1da177e4 | 2383 | console->flags &= ~CON_ENABLED; |
ac751efa | 2384 | console_unlock(); |
1da177e4 LT |
2385 | } |
2386 | EXPORT_SYMBOL(console_stop); | |
2387 | ||
2388 | void console_start(struct console *console) | |
2389 | { | |
ac751efa | 2390 | console_lock(); |
1da177e4 | 2391 | console->flags |= CON_ENABLED; |
ac751efa | 2392 | console_unlock(); |
1da177e4 LT |
2393 | } |
2394 | EXPORT_SYMBOL(console_start); | |
2395 | ||
7bf69395 FDN |
2396 | static int __read_mostly keep_bootcon; |
2397 | ||
2398 | static int __init keep_bootcon_setup(char *str) | |
2399 | { | |
2400 | keep_bootcon = 1; | |
2401 | printk(KERN_INFO "debug: skip boot console de-registration.\n"); | |
2402 | ||
2403 | return 0; | |
2404 | } | |
2405 | ||
2406 | early_param("keep_bootcon", keep_bootcon_setup); | |
2407 | ||
1da177e4 LT |
2408 | /* |
2409 | * The console driver calls this routine during kernel initialization | |
2410 | * to register the console printing procedure with printk() and to | |
2411 | * print any messages that were printed by the kernel before the | |
2412 | * console driver was initialized. | |
4d091611 RG |
2413 | * |
2414 | * This can happen pretty early during the boot process (because of | |
2415 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2416 | * of what kernel features are used - they may not be initialised yet. | |
2417 | * | |
2418 | * There are two types of consoles - bootconsoles (early_printk) and | |
2419 | * "real" consoles (everything which is not a bootconsole) which are | |
2420 | * handled differently. | |
2421 | * - Any number of bootconsoles can be registered at any time. | |
2422 | * - As soon as a "real" console is registered, all bootconsoles | |
2423 | * will be unregistered automatically. | |
2424 | * - Once a "real" console is registered, any attempt to register a | |
2425 | * bootconsoles will be rejected | |
1da177e4 | 2426 | */ |
4d091611 | 2427 | void register_console(struct console *newcon) |
1da177e4 | 2428 | { |
40dc5651 | 2429 | int i; |
1da177e4 | 2430 | unsigned long flags; |
4d091611 | 2431 | struct console *bcon = NULL; |
1da177e4 | 2432 | |
4d091611 RG |
2433 | /* |
2434 | * before we register a new CON_BOOT console, make sure we don't | |
2435 | * already have a valid console | |
2436 | */ | |
2437 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2438 | /* find the last or real console */ | |
2439 | for_each_console(bcon) { | |
2440 | if (!(bcon->flags & CON_BOOT)) { | |
2441 | printk(KERN_INFO "Too late to register bootconsole %s%d\n", | |
2442 | newcon->name, newcon->index); | |
2443 | return; | |
2444 | } | |
2445 | } | |
69331af7 GH |
2446 | } |
2447 | ||
4d091611 RG |
2448 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2449 | bcon = console_drivers; | |
2450 | ||
2451 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2452 | preferred_console = selected_console; |
2453 | ||
4d091611 RG |
2454 | if (newcon->early_setup) |
2455 | newcon->early_setup(); | |
18a8bd94 | 2456 | |
1da177e4 LT |
2457 | /* |
2458 | * See if we want to use this console driver. If we | |
2459 | * didn't select a console we take the first one | |
2460 | * that registers here. | |
2461 | */ | |
2462 | if (preferred_console < 0) { | |
4d091611 RG |
2463 | if (newcon->index < 0) |
2464 | newcon->index = 0; | |
2465 | if (newcon->setup == NULL || | |
2466 | newcon->setup(newcon, NULL) == 0) { | |
2467 | newcon->flags |= CON_ENABLED; | |
2468 | if (newcon->device) { | |
2469 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2470 | preferred_console = 0; |
2471 | } | |
1da177e4 LT |
2472 | } |
2473 | } | |
2474 | ||
2475 | /* | |
2476 | * See if this console matches one we selected on | |
2477 | * the command line. | |
2478 | */ | |
40dc5651 JJ |
2479 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
2480 | i++) { | |
62de970a PH |
2481 | BUILD_BUG_ON(sizeof(console_cmdline[i].name) != |
2482 | sizeof(newcon->name)); | |
4d091611 | 2483 | if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
1da177e4 | 2484 | continue; |
4d091611 RG |
2485 | if (newcon->index >= 0 && |
2486 | newcon->index != console_cmdline[i].index) | |
1da177e4 | 2487 | continue; |
4d091611 RG |
2488 | if (newcon->index < 0) |
2489 | newcon->index = console_cmdline[i].index; | |
f7511d5f ST |
2490 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
2491 | if (console_cmdline[i].brl_options) { | |
4d091611 RG |
2492 | newcon->flags |= CON_BRL; |
2493 | braille_register_console(newcon, | |
f7511d5f ST |
2494 | console_cmdline[i].index, |
2495 | console_cmdline[i].options, | |
2496 | console_cmdline[i].brl_options); | |
2497 | return; | |
2498 | } | |
2499 | #endif | |
4d091611 RG |
2500 | if (newcon->setup && |
2501 | newcon->setup(newcon, console_cmdline[i].options) != 0) | |
1da177e4 | 2502 | break; |
4d091611 RG |
2503 | newcon->flags |= CON_ENABLED; |
2504 | newcon->index = console_cmdline[i].index; | |
ab4af03a | 2505 | if (i == selected_console) { |
4d091611 | 2506 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2507 | preferred_console = selected_console; |
2508 | } | |
1da177e4 LT |
2509 | break; |
2510 | } | |
2511 | ||
4d091611 | 2512 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2513 | return; |
2514 | ||
8259cf43 RG |
2515 | /* |
2516 | * If we have a bootconsole, and are switching to a real console, | |
2517 | * don't print everything out again, since when the boot console, and | |
2518 | * the real console are the same physical device, it's annoying to | |
2519 | * see the beginning boot messages twice | |
2520 | */ | |
2521 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2522 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2523 | |
2524 | /* | |
2525 | * Put this console in the list - keep the | |
2526 | * preferred driver at the head of the list. | |
2527 | */ | |
ac751efa | 2528 | console_lock(); |
4d091611 RG |
2529 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2530 | newcon->next = console_drivers; | |
2531 | console_drivers = newcon; | |
2532 | if (newcon->next) | |
2533 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2534 | } else { |
4d091611 RG |
2535 | newcon->next = console_drivers->next; |
2536 | console_drivers->next = newcon; | |
1da177e4 | 2537 | } |
4d091611 | 2538 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2539 | /* |
ac751efa | 2540 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2541 | * for us. |
2542 | */ | |
07354eb1 | 2543 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2544 | console_seq = syslog_seq; |
2545 | console_idx = syslog_idx; | |
5becfb1d | 2546 | console_prev = syslog_prev; |
07354eb1 | 2547 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2548 | /* |
2549 | * We're about to replay the log buffer. Only do this to the | |
2550 | * just-registered console to avoid excessive message spam to | |
2551 | * the already-registered consoles. | |
2552 | */ | |
2553 | exclusive_console = newcon; | |
1da177e4 | 2554 | } |
ac751efa | 2555 | console_unlock(); |
fbc92a34 | 2556 | console_sysfs_notify(); |
8259cf43 RG |
2557 | |
2558 | /* | |
2559 | * By unregistering the bootconsoles after we enable the real console | |
2560 | * we get the "console xxx enabled" message on all the consoles - | |
2561 | * boot consoles, real consoles, etc - this is to ensure that end | |
2562 | * users know there might be something in the kernel's log buffer that | |
2563 | * went to the bootconsole (that they do not see on the real console) | |
2564 | */ | |
7bf69395 FDN |
2565 | if (bcon && |
2566 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2567 | !keep_bootcon) { | |
8259cf43 RG |
2568 | /* we need to iterate through twice, to make sure we print |
2569 | * everything out, before we unregister the console(s) | |
2570 | */ | |
2571 | printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", | |
2572 | newcon->name, newcon->index); | |
2573 | for_each_console(bcon) | |
2574 | if (bcon->flags & CON_BOOT) | |
2575 | unregister_console(bcon); | |
2576 | } else { | |
2577 | printk(KERN_INFO "%sconsole [%s%d] enabled\n", | |
2578 | (newcon->flags & CON_BOOT) ? "boot" : "" , | |
2579 | newcon->name, newcon->index); | |
2580 | } | |
1da177e4 LT |
2581 | } |
2582 | EXPORT_SYMBOL(register_console); | |
2583 | ||
40dc5651 | 2584 | int unregister_console(struct console *console) |
1da177e4 | 2585 | { |
40dc5651 | 2586 | struct console *a, *b; |
1da177e4 LT |
2587 | int res = 1; |
2588 | ||
f7511d5f ST |
2589 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
2590 | if (console->flags & CON_BRL) | |
2591 | return braille_unregister_console(console); | |
2592 | #endif | |
2593 | ||
ac751efa | 2594 | console_lock(); |
1da177e4 LT |
2595 | if (console_drivers == console) { |
2596 | console_drivers=console->next; | |
2597 | res = 0; | |
e9b15b54 | 2598 | } else if (console_drivers) { |
1da177e4 LT |
2599 | for (a=console_drivers->next, b=console_drivers ; |
2600 | a; b=a, a=b->next) { | |
2601 | if (a == console) { | |
2602 | b->next = a->next; | |
2603 | res = 0; | |
2604 | break; | |
40dc5651 | 2605 | } |
1da177e4 LT |
2606 | } |
2607 | } | |
40dc5651 | 2608 | |
69331af7 | 2609 | /* |
ab4af03a GE |
2610 | * If this isn't the last console and it has CON_CONSDEV set, we |
2611 | * need to set it on the next preferred console. | |
1da177e4 | 2612 | */ |
69331af7 | 2613 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2614 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2615 | |
ac751efa | 2616 | console_unlock(); |
fbc92a34 | 2617 | console_sysfs_notify(); |
1da177e4 LT |
2618 | return res; |
2619 | } | |
2620 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2621 | |
034260d6 | 2622 | static int __init printk_late_init(void) |
0c5564bd | 2623 | { |
4d091611 RG |
2624 | struct console *con; |
2625 | ||
2626 | for_each_console(con) { | |
4c30c6f5 | 2627 | if (!keep_bootcon && con->flags & CON_BOOT) { |
cb00e99c | 2628 | printk(KERN_INFO "turn off boot console %s%d\n", |
4d091611 | 2629 | con->name, con->index); |
42c2c8c8 | 2630 | unregister_console(con); |
cb00e99c | 2631 | } |
0c5564bd | 2632 | } |
034260d6 | 2633 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2634 | return 0; |
2635 | } | |
034260d6 | 2636 | late_initcall(printk_late_init); |
0c5564bd | 2637 | |
7ef3d2fd | 2638 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2639 | /* |
2640 | * Delayed printk version, for scheduler-internal messages: | |
2641 | */ | |
2642 | #define PRINTK_BUF_SIZE 512 | |
2643 | ||
2644 | #define PRINTK_PENDING_WAKEUP 0x01 | |
2645 | #define PRINTK_PENDING_SCHED 0x02 | |
2646 | ||
2647 | static DEFINE_PER_CPU(int, printk_pending); | |
2648 | static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); | |
2649 | ||
2650 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2651 | { | |
2652 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2653 | ||
2654 | if (pending & PRINTK_PENDING_SCHED) { | |
2655 | char *buf = __get_cpu_var(printk_sched_buf); | |
2656 | printk(KERN_WARNING "[sched_delayed] %s", buf); | |
2657 | } | |
2658 | ||
2659 | if (pending & PRINTK_PENDING_WAKEUP) | |
2660 | wake_up_interruptible(&log_wait); | |
2661 | } | |
2662 | ||
2663 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2664 | .func = wake_up_klogd_work_func, | |
2665 | .flags = IRQ_WORK_LAZY, | |
2666 | }; | |
2667 | ||
2668 | void wake_up_klogd(void) | |
2669 | { | |
2670 | preempt_disable(); | |
2671 | if (waitqueue_active(&log_wait)) { | |
2672 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
2673 | irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); | |
2674 | } | |
2675 | preempt_enable(); | |
2676 | } | |
717115e1 | 2677 | |
3984bb13 | 2678 | int printk_deferred(const char *fmt, ...) |
600e1458 PZ |
2679 | { |
2680 | unsigned long flags; | |
2681 | va_list args; | |
2682 | char *buf; | |
2683 | int r; | |
2684 | ||
2685 | local_irq_save(flags); | |
2686 | buf = __get_cpu_var(printk_sched_buf); | |
2687 | ||
2688 | va_start(args, fmt); | |
2689 | r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); | |
2690 | va_end(args); | |
2691 | ||
2692 | __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); | |
74876a98 | 2693 | irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); |
600e1458 PZ |
2694 | local_irq_restore(flags); |
2695 | ||
2696 | return r; | |
2697 | } | |
2698 | ||
1da177e4 LT |
2699 | /* |
2700 | * printk rate limiting, lifted from the networking subsystem. | |
2701 | * | |
641de9d8 UKK |
2702 | * This enforces a rate limit: not more than 10 kernel messages |
2703 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2704 | */ |
641de9d8 UKK |
2705 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2706 | ||
5c828713 | 2707 | int __printk_ratelimit(const char *func) |
1da177e4 | 2708 | { |
5c828713 | 2709 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2710 | } |
5c828713 | 2711 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2712 | |
2713 | /** | |
2714 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2715 | * @caller_jiffies: pointer to caller's state | |
2716 | * @interval_msecs: minimum interval between prints | |
2717 | * | |
2718 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2719 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2720 | * returned true. | |
2721 | */ | |
2722 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2723 | unsigned int interval_msecs) | |
2724 | { | |
f2d28a2e GK |
2725 | if (*caller_jiffies == 0 |
2726 | || !time_in_range(jiffies, *caller_jiffies, | |
2727 | *caller_jiffies | |
2728 | + msecs_to_jiffies(interval_msecs))) { | |
2729 | *caller_jiffies = jiffies; | |
f46c4833 AM |
2730 | return true; |
2731 | } | |
2732 | return false; | |
2733 | } | |
2734 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2735 | |
2736 | static DEFINE_SPINLOCK(dump_list_lock); | |
2737 | static LIST_HEAD(dump_list); | |
2738 | ||
2739 | /** | |
2740 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2741 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2742 | * |
2743 | * Adds a kernel log dumper to the system. The dump callback in the | |
2744 | * structure will be called when the kernel oopses or panics and must be | |
2745 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2746 | */ | |
2747 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2748 | { | |
2749 | unsigned long flags; | |
2750 | int err = -EBUSY; | |
2751 | ||
2752 | /* The dump callback needs to be set */ | |
2753 | if (!dumper->dump) | |
2754 | return -EINVAL; | |
2755 | ||
2756 | spin_lock_irqsave(&dump_list_lock, flags); | |
2757 | /* Don't allow registering multiple times */ | |
2758 | if (!dumper->registered) { | |
2759 | dumper->registered = 1; | |
fb842b00 | 2760 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2761 | err = 0; |
2762 | } | |
2763 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2764 | ||
2765 | return err; | |
2766 | } | |
2767 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2768 | ||
2769 | /** | |
2770 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2771 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2772 | * |
2773 | * Removes a dump device from the system. Returns zero on success and | |
2774 | * %-EINVAL otherwise. | |
2775 | */ | |
2776 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2777 | { | |
2778 | unsigned long flags; | |
2779 | int err = -EINVAL; | |
2780 | ||
2781 | spin_lock_irqsave(&dump_list_lock, flags); | |
2782 | if (dumper->registered) { | |
2783 | dumper->registered = 0; | |
fb842b00 | 2784 | list_del_rcu(&dumper->list); |
456b565c SK |
2785 | err = 0; |
2786 | } | |
2787 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2788 | synchronize_rcu(); |
456b565c SK |
2789 | |
2790 | return err; | |
2791 | } | |
2792 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2793 | ||
7ff9554b KS |
2794 | static bool always_kmsg_dump; |
2795 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2796 | ||
456b565c SK |
2797 | /** |
2798 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2799 | * @reason: the reason (oops, panic etc) for dumping | |
2800 | * | |
e2ae715d KS |
2801 | * Call each of the registered dumper's dump() callback, which can |
2802 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2803 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2804 | */ |
2805 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2806 | { | |
456b565c | 2807 | struct kmsg_dumper *dumper; |
456b565c SK |
2808 | unsigned long flags; |
2809 | ||
c22ab332 MG |
2810 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2811 | return; | |
2812 | ||
e2ae715d KS |
2813 | rcu_read_lock(); |
2814 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2815 | if (dumper->max_reason && reason > dumper->max_reason) | |
2816 | continue; | |
2817 | ||
2818 | /* initialize iterator with data about the stored records */ | |
2819 | dumper->active = true; | |
2820 | ||
2821 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2822 | dumper->cur_seq = clear_seq; | |
2823 | dumper->cur_idx = clear_idx; | |
2824 | dumper->next_seq = log_next_seq; | |
2825 | dumper->next_idx = log_next_idx; | |
2826 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2827 | ||
2828 | /* invoke dumper which will iterate over records */ | |
2829 | dumper->dump(dumper, reason); | |
2830 | ||
2831 | /* reset iterator */ | |
2832 | dumper->active = false; | |
2833 | } | |
2834 | rcu_read_unlock(); | |
2835 | } | |
2836 | ||
2837 | /** | |
533827c9 | 2838 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2839 | * @dumper: registered kmsg dumper |
2840 | * @syslog: include the "<4>" prefixes | |
2841 | * @line: buffer to copy the line to | |
2842 | * @size: maximum size of the buffer | |
2843 | * @len: length of line placed into buffer | |
2844 | * | |
2845 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2846 | * record, and copy one record into the provided buffer. | |
2847 | * | |
2848 | * Consecutive calls will return the next available record moving | |
2849 | * towards the end of the buffer with the youngest messages. | |
2850 | * | |
2851 | * A return value of FALSE indicates that there are no more records to | |
2852 | * read. | |
533827c9 AV |
2853 | * |
2854 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2855 | */ |
533827c9 AV |
2856 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2857 | char *line, size_t size, size_t *len) | |
e2ae715d | 2858 | { |
e2ae715d KS |
2859 | struct log *msg; |
2860 | size_t l = 0; | |
2861 | bool ret = false; | |
2862 | ||
2863 | if (!dumper->active) | |
2864 | goto out; | |
7ff9554b | 2865 | |
e2ae715d KS |
2866 | if (dumper->cur_seq < log_first_seq) { |
2867 | /* messages are gone, move to first available one */ | |
2868 | dumper->cur_seq = log_first_seq; | |
2869 | dumper->cur_idx = log_first_idx; | |
2870 | } | |
456b565c | 2871 | |
e2ae715d | 2872 | /* last entry */ |
533827c9 | 2873 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2874 | goto out; |
456b565c | 2875 | |
e2ae715d | 2876 | msg = log_from_idx(dumper->cur_idx); |
5becfb1d | 2877 | l = msg_print_text(msg, 0, syslog, line, size); |
e2ae715d KS |
2878 | |
2879 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2880 | dumper->cur_seq++; | |
2881 | ret = true; | |
e2ae715d KS |
2882 | out: |
2883 | if (len) | |
2884 | *len = l; | |
2885 | return ret; | |
2886 | } | |
533827c9 AV |
2887 | |
2888 | /** | |
2889 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2890 | * @dumper: registered kmsg dumper | |
2891 | * @syslog: include the "<4>" prefixes | |
2892 | * @line: buffer to copy the line to | |
2893 | * @size: maximum size of the buffer | |
2894 | * @len: length of line placed into buffer | |
2895 | * | |
2896 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2897 | * record, and copy one record into the provided buffer. | |
2898 | * | |
2899 | * Consecutive calls will return the next available record moving | |
2900 | * towards the end of the buffer with the youngest messages. | |
2901 | * | |
2902 | * A return value of FALSE indicates that there are no more records to | |
2903 | * read. | |
2904 | */ | |
2905 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2906 | char *line, size_t size, size_t *len) | |
2907 | { | |
2908 | unsigned long flags; | |
2909 | bool ret; | |
2910 | ||
2911 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2912 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2913 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2914 | ||
2915 | return ret; | |
2916 | } | |
e2ae715d KS |
2917 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2918 | ||
2919 | /** | |
2920 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2921 | * @dumper: registered kmsg dumper | |
2922 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2923 | * @buf: buffer to copy the line to |
e2ae715d KS |
2924 | * @size: maximum size of the buffer |
2925 | * @len: length of line placed into buffer | |
2926 | * | |
2927 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2928 | * with as many of the the *youngest* kmsg records that fit into it. | |
2929 | * If the buffer is large enough, all available kmsg records will be | |
2930 | * copied with a single call. | |
2931 | * | |
2932 | * Consecutive calls will fill the buffer with the next block of | |
2933 | * available older records, not including the earlier retrieved ones. | |
2934 | * | |
2935 | * A return value of FALSE indicates that there are no more records to | |
2936 | * read. | |
2937 | */ | |
2938 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
2939 | char *buf, size_t size, size_t *len) | |
2940 | { | |
2941 | unsigned long flags; | |
2942 | u64 seq; | |
2943 | u32 idx; | |
2944 | u64 next_seq; | |
2945 | u32 next_idx; | |
5becfb1d | 2946 | enum log_flags prev; |
e2ae715d KS |
2947 | size_t l = 0; |
2948 | bool ret = false; | |
2949 | ||
2950 | if (!dumper->active) | |
2951 | goto out; | |
2952 | ||
2953 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2954 | if (dumper->cur_seq < log_first_seq) { | |
2955 | /* messages are gone, move to first available one */ | |
2956 | dumper->cur_seq = log_first_seq; | |
2957 | dumper->cur_idx = log_first_idx; | |
2958 | } | |
2959 | ||
2960 | /* last entry */ | |
2961 | if (dumper->cur_seq >= dumper->next_seq) { | |
2962 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2963 | goto out; | |
2964 | } | |
2965 | ||
2966 | /* calculate length of entire buffer */ | |
2967 | seq = dumper->cur_seq; | |
2968 | idx = dumper->cur_idx; | |
5becfb1d | 2969 | prev = 0; |
e2ae715d KS |
2970 | while (seq < dumper->next_seq) { |
2971 | struct log *msg = log_from_idx(idx); | |
2972 | ||
5becfb1d | 2973 | l += msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2974 | idx = log_next(idx); |
2975 | seq++; | |
5becfb1d | 2976 | prev = msg->flags; |
e2ae715d KS |
2977 | } |
2978 | ||
2979 | /* move first record forward until length fits into the buffer */ | |
2980 | seq = dumper->cur_seq; | |
2981 | idx = dumper->cur_idx; | |
5becfb1d | 2982 | prev = 0; |
e2ae715d KS |
2983 | while (l > size && seq < dumper->next_seq) { |
2984 | struct log *msg = log_from_idx(idx); | |
456b565c | 2985 | |
5becfb1d | 2986 | l -= msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2987 | idx = log_next(idx); |
2988 | seq++; | |
5becfb1d | 2989 | prev = msg->flags; |
456b565c | 2990 | } |
e2ae715d KS |
2991 | |
2992 | /* last message in next interation */ | |
2993 | next_seq = seq; | |
2994 | next_idx = idx; | |
2995 | ||
2996 | l = 0; | |
2997 | while (seq < dumper->next_seq) { | |
2998 | struct log *msg = log_from_idx(idx); | |
2999 | ||
5becfb1d | 3000 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
e2ae715d KS |
3001 | idx = log_next(idx); |
3002 | seq++; | |
5becfb1d | 3003 | prev = msg->flags; |
e2ae715d KS |
3004 | } |
3005 | ||
3006 | dumper->next_seq = next_seq; | |
3007 | dumper->next_idx = next_idx; | |
3008 | ret = true; | |
7ff9554b | 3009 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
3010 | out: |
3011 | if (len) | |
3012 | *len = l; | |
3013 | return ret; | |
3014 | } | |
3015 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 3016 | |
533827c9 AV |
3017 | /** |
3018 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
3019 | * @dumper: registered kmsg dumper | |
3020 | * | |
3021 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3022 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3023 | * times within the same dumper.dump() callback. | |
3024 | * | |
3025 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
3026 | */ | |
3027 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
3028 | { | |
3029 | dumper->cur_seq = clear_seq; | |
3030 | dumper->cur_idx = clear_idx; | |
3031 | dumper->next_seq = log_next_seq; | |
3032 | dumper->next_idx = log_next_idx; | |
3033 | } | |
3034 | ||
e2ae715d KS |
3035 | /** |
3036 | * kmsg_dump_rewind - reset the interator | |
3037 | * @dumper: registered kmsg dumper | |
3038 | * | |
3039 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3040 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3041 | * times within the same dumper.dump() callback. | |
3042 | */ | |
3043 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
3044 | { | |
3045 | unsigned long flags; | |
3046 | ||
3047 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 3048 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 3049 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 3050 | } |
e2ae715d | 3051 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 3052 | |
98e5e1bf TH |
3053 | static char dump_stack_arch_desc_str[128]; |
3054 | ||
3055 | /** | |
3056 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
3057 | * @fmt: printf-style format string | |
3058 | * @...: arguments for the format string | |
3059 | * | |
3060 | * The configured string will be printed right after utsname during task | |
3061 | * dumps. Usually used to add arch-specific system identifiers. If an | |
3062 | * arch wants to make use of such an ID string, it should initialize this | |
3063 | * as soon as possible during boot. | |
3064 | */ | |
3065 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
3066 | { | |
3067 | va_list args; | |
3068 | ||
3069 | va_start(args, fmt); | |
3070 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
3071 | fmt, args); | |
3072 | va_end(args); | |
3073 | } | |
3074 | ||
196779b9 TH |
3075 | /** |
3076 | * dump_stack_print_info - print generic debug info for dump_stack() | |
3077 | * @log_lvl: log level | |
3078 | * | |
3079 | * Arch-specific dump_stack() implementations can use this function to | |
3080 | * print out the same debug information as the generic dump_stack(). | |
3081 | */ | |
3082 | void dump_stack_print_info(const char *log_lvl) | |
3083 | { | |
3084 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
3085 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
3086 | print_tainted(), init_utsname()->release, | |
3087 | (int)strcspn(init_utsname()->version, " "), | |
3088 | init_utsname()->version); | |
98e5e1bf TH |
3089 | |
3090 | if (dump_stack_arch_desc_str[0] != '\0') | |
3091 | printk("%sHardware name: %s\n", | |
3092 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
3093 | |
3094 | print_worker_info(log_lvl, current); | |
196779b9 TH |
3095 | } |
3096 | ||
a43cb95d TH |
3097 | /** |
3098 | * show_regs_print_info - print generic debug info for show_regs() | |
3099 | * @log_lvl: log level | |
3100 | * | |
3101 | * show_regs() implementations can use this function to print out generic | |
3102 | * debug information. | |
3103 | */ | |
3104 | void show_regs_print_info(const char *log_lvl) | |
3105 | { | |
3106 | dump_stack_print_info(log_lvl); | |
3107 | ||
3108 | printk("%stask: %p ti: %p task.ti: %p\n", | |
3109 | log_lvl, current, current_thread_info(), | |
3110 | task_thread_info(current)); | |
3111 | } | |
3112 | ||
7ef3d2fd | 3113 | #endif |