Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/fork.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'fork.c' contains the help-routines for the 'fork' system call | |
9 | * (see also entry.S and others). | |
10 | * Fork is rather simple, once you get the hang of it, but the memory | |
11 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
12 | */ | |
13 | ||
1da177e4 LT |
14 | #include <linux/slab.h> |
15 | #include <linux/init.h> | |
16 | #include <linux/unistd.h> | |
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/completion.h> | |
6b3286ed | 20 | #include <linux/mnt_namespace.h> |
1da177e4 LT |
21 | #include <linux/personality.h> |
22 | #include <linux/mempolicy.h> | |
23 | #include <linux/sem.h> | |
24 | #include <linux/file.h> | |
9f3acc31 | 25 | #include <linux/fdtable.h> |
da9cbc87 | 26 | #include <linux/iocontext.h> |
1da177e4 LT |
27 | #include <linux/key.h> |
28 | #include <linux/binfmts.h> | |
29 | #include <linux/mman.h> | |
30 | #include <linux/fs.h> | |
ab516013 | 31 | #include <linux/nsproxy.h> |
c59ede7b | 32 | #include <linux/capability.h> |
1da177e4 | 33 | #include <linux/cpu.h> |
b4f48b63 | 34 | #include <linux/cgroup.h> |
1da177e4 | 35 | #include <linux/security.h> |
a1e78772 | 36 | #include <linux/hugetlb.h> |
1da177e4 LT |
37 | #include <linux/swap.h> |
38 | #include <linux/syscalls.h> | |
39 | #include <linux/jiffies.h> | |
40 | #include <linux/futex.h> | |
7c3ab738 | 41 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 42 | #include <linux/rcupdate.h> |
1da177e4 LT |
43 | #include <linux/ptrace.h> |
44 | #include <linux/mount.h> | |
45 | #include <linux/audit.h> | |
78fb7466 | 46 | #include <linux/memcontrol.h> |
1da177e4 LT |
47 | #include <linux/profile.h> |
48 | #include <linux/rmap.h> | |
49 | #include <linux/acct.h> | |
8f0ab514 | 50 | #include <linux/tsacct_kern.h> |
9f46080c | 51 | #include <linux/cn_proc.h> |
ba96a0c8 | 52 | #include <linux/freezer.h> |
ca74e92b | 53 | #include <linux/delayacct.h> |
ad4ecbcb | 54 | #include <linux/taskstats_kern.h> |
0a425405 | 55 | #include <linux/random.h> |
522ed776 | 56 | #include <linux/tty.h> |
6f4e6433 | 57 | #include <linux/proc_fs.h> |
fd0928df | 58 | #include <linux/blkdev.h> |
1da177e4 LT |
59 | |
60 | #include <asm/pgtable.h> | |
61 | #include <asm/pgalloc.h> | |
62 | #include <asm/uaccess.h> | |
63 | #include <asm/mmu_context.h> | |
64 | #include <asm/cacheflush.h> | |
65 | #include <asm/tlbflush.h> | |
66 | ||
67 | /* | |
68 | * Protected counters by write_lock_irq(&tasklist_lock) | |
69 | */ | |
70 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
71 | int nr_threads; /* The idle threads do not count.. */ | |
72 | ||
73 | int max_threads; /* tunable limit on nr_threads */ | |
74 | ||
75 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
76 | ||
c59923a1 | 77 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
78 | |
79 | int nr_processes(void) | |
80 | { | |
81 | int cpu; | |
82 | int total = 0; | |
83 | ||
84 | for_each_online_cpu(cpu) | |
85 | total += per_cpu(process_counts, cpu); | |
86 | ||
87 | return total; | |
88 | } | |
89 | ||
90 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
91 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
92 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 93 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
94 | #endif |
95 | ||
b69c49b7 FT |
96 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
97 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) | |
98 | { | |
99 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
100 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; | |
101 | #else | |
102 | gfp_t mask = GFP_KERNEL; | |
103 | #endif | |
104 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); | |
105 | } | |
106 | ||
107 | static inline void free_thread_info(struct thread_info *ti) | |
108 | { | |
109 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); | |
110 | } | |
111 | #endif | |
112 | ||
1da177e4 | 113 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 114 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
115 | |
116 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 117 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
118 | |
119 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 120 | struct kmem_cache *files_cachep; |
1da177e4 LT |
121 | |
122 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 123 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
124 | |
125 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 126 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
127 | |
128 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 129 | static struct kmem_cache *mm_cachep; |
1da177e4 LT |
130 | |
131 | void free_task(struct task_struct *tsk) | |
132 | { | |
3e26c149 | 133 | prop_local_destroy_single(&tsk->dirties); |
f7e4217b | 134 | free_thread_info(tsk->stack); |
23f78d4a | 135 | rt_mutex_debug_task_free(tsk); |
1da177e4 LT |
136 | free_task_struct(tsk); |
137 | } | |
138 | EXPORT_SYMBOL(free_task); | |
139 | ||
158d9ebd | 140 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 141 | { |
270f722d | 142 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
143 | WARN_ON(atomic_read(&tsk->usage)); |
144 | WARN_ON(tsk == current); | |
145 | ||
1da177e4 LT |
146 | security_task_free(tsk); |
147 | free_uid(tsk->user); | |
148 | put_group_info(tsk->group_info); | |
35df17c5 | 149 | delayacct_tsk_free(tsk); |
1da177e4 LT |
150 | |
151 | if (!profile_handoff_task(tsk)) | |
152 | free_task(tsk); | |
153 | } | |
154 | ||
2adee9b3 SS |
155 | /* |
156 | * macro override instead of weak attribute alias, to workaround | |
157 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
158 | */ | |
159 | #ifndef arch_task_cache_init | |
160 | #define arch_task_cache_init() | |
161 | #endif | |
61c4628b | 162 | |
1da177e4 LT |
163 | void __init fork_init(unsigned long mempages) |
164 | { | |
165 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
166 | #ifndef ARCH_MIN_TASKALIGN | |
167 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
168 | #endif | |
169 | /* create a slab on which task_structs can be allocated */ | |
170 | task_struct_cachep = | |
171 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
20c2df83 | 172 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL); |
1da177e4 LT |
173 | #endif |
174 | ||
61c4628b SS |
175 | /* do the arch specific task caches init */ |
176 | arch_task_cache_init(); | |
177 | ||
1da177e4 LT |
178 | /* |
179 | * The default maximum number of threads is set to a safe | |
180 | * value: the thread structures can take up at most half | |
181 | * of memory. | |
182 | */ | |
183 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
184 | ||
185 | /* | |
186 | * we need to allow at least 20 threads to boot a system | |
187 | */ | |
188 | if(max_threads < 20) | |
189 | max_threads = 20; | |
190 | ||
191 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
192 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
193 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
194 | init_task.signal->rlim[RLIMIT_NPROC]; | |
195 | } | |
196 | ||
61c4628b SS |
197 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
198 | struct task_struct *src) | |
199 | { | |
200 | *dst = *src; | |
201 | return 0; | |
202 | } | |
203 | ||
1da177e4 LT |
204 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
205 | { | |
206 | struct task_struct *tsk; | |
207 | struct thread_info *ti; | |
3e26c149 | 208 | int err; |
1da177e4 LT |
209 | |
210 | prepare_to_copy(orig); | |
211 | ||
212 | tsk = alloc_task_struct(); | |
213 | if (!tsk) | |
214 | return NULL; | |
215 | ||
216 | ti = alloc_thread_info(tsk); | |
217 | if (!ti) { | |
218 | free_task_struct(tsk); | |
219 | return NULL; | |
220 | } | |
221 | ||
61c4628b SS |
222 | err = arch_dup_task_struct(tsk, orig); |
223 | if (err) | |
224 | goto out; | |
225 | ||
f7e4217b | 226 | tsk->stack = ti; |
3e26c149 PZ |
227 | |
228 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
229 | if (err) |
230 | goto out; | |
3e26c149 | 231 | |
10ebffde | 232 | setup_thread_stack(tsk, orig); |
1da177e4 | 233 | |
0a425405 AV |
234 | #ifdef CONFIG_CC_STACKPROTECTOR |
235 | tsk->stack_canary = get_random_int(); | |
236 | #endif | |
237 | ||
1da177e4 LT |
238 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
239 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 240 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 241 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 242 | tsk->btrace_seq = 0; |
6c5c9341 | 243 | #endif |
a0aa7f68 | 244 | tsk->splice_pipe = NULL; |
1da177e4 | 245 | return tsk; |
61c4628b SS |
246 | |
247 | out: | |
248 | free_thread_info(ti); | |
249 | free_task_struct(tsk); | |
250 | return NULL; | |
1da177e4 LT |
251 | } |
252 | ||
253 | #ifdef CONFIG_MMU | |
a39bc516 | 254 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 255 | { |
fd3e42fc | 256 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
257 | struct rb_node **rb_link, *rb_parent; |
258 | int retval; | |
259 | unsigned long charge; | |
260 | struct mempolicy *pol; | |
261 | ||
262 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 263 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
264 | /* |
265 | * Not linked in yet - no deadlock potential: | |
266 | */ | |
267 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 268 | |
1da177e4 LT |
269 | mm->locked_vm = 0; |
270 | mm->mmap = NULL; | |
271 | mm->mmap_cache = NULL; | |
272 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 273 | mm->cached_hole_size = ~0UL; |
1da177e4 | 274 | mm->map_count = 0; |
1da177e4 LT |
275 | cpus_clear(mm->cpu_vm_mask); |
276 | mm->mm_rb = RB_ROOT; | |
277 | rb_link = &mm->mm_rb.rb_node; | |
278 | rb_parent = NULL; | |
279 | pprev = &mm->mmap; | |
280 | ||
fd3e42fc | 281 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
282 | struct file *file; |
283 | ||
284 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
285 | long pages = vma_pages(mpnt); |
286 | mm->total_vm -= pages; | |
ab50b8ed | 287 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 288 | -pages); |
1da177e4 LT |
289 | continue; |
290 | } | |
291 | charge = 0; | |
292 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
293 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
294 | if (security_vm_enough_memory(len)) | |
295 | goto fail_nomem; | |
296 | charge = len; | |
297 | } | |
e94b1766 | 298 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
299 | if (!tmp) |
300 | goto fail_nomem; | |
301 | *tmp = *mpnt; | |
846a16bf | 302 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
303 | retval = PTR_ERR(pol); |
304 | if (IS_ERR(pol)) | |
305 | goto fail_nomem_policy; | |
306 | vma_set_policy(tmp, pol); | |
307 | tmp->vm_flags &= ~VM_LOCKED; | |
308 | tmp->vm_mm = mm; | |
309 | tmp->vm_next = NULL; | |
310 | anon_vma_link(tmp); | |
311 | file = tmp->vm_file; | |
312 | if (file) { | |
f3a43f3f | 313 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
314 | get_file(file); |
315 | if (tmp->vm_flags & VM_DENYWRITE) | |
316 | atomic_dec(&inode->i_writecount); | |
23ff4440 | 317 | |
1da177e4 LT |
318 | /* insert tmp into the share list, just after mpnt */ |
319 | spin_lock(&file->f_mapping->i_mmap_lock); | |
320 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
321 | flush_dcache_mmap_lock(file->f_mapping); | |
322 | vma_prio_tree_add(tmp, mpnt); | |
323 | flush_dcache_mmap_unlock(file->f_mapping); | |
324 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
325 | } | |
326 | ||
a1e78772 MG |
327 | /* |
328 | * Clear hugetlb-related page reserves for children. This only | |
329 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
330 | * are not guaranteed to succeed, even if read-only | |
331 | */ | |
332 | if (is_vm_hugetlb_page(tmp)) | |
333 | reset_vma_resv_huge_pages(tmp); | |
334 | ||
1da177e4 | 335 | /* |
7ee78232 | 336 | * Link in the new vma and copy the page table entries. |
1da177e4 | 337 | */ |
1da177e4 LT |
338 | *pprev = tmp; |
339 | pprev = &tmp->vm_next; | |
340 | ||
341 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
342 | rb_link = &tmp->vm_rb.rb_right; | |
343 | rb_parent = &tmp->vm_rb; | |
344 | ||
345 | mm->map_count++; | |
0b0db14c | 346 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
347 | |
348 | if (tmp->vm_ops && tmp->vm_ops->open) | |
349 | tmp->vm_ops->open(tmp); | |
350 | ||
351 | if (retval) | |
352 | goto out; | |
353 | } | |
d6dd61c8 JF |
354 | /* a new mm has just been created */ |
355 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 356 | retval = 0; |
1da177e4 | 357 | out: |
7ee78232 | 358 | up_write(&mm->mmap_sem); |
fd3e42fc | 359 | flush_tlb_mm(oldmm); |
1da177e4 LT |
360 | up_write(&oldmm->mmap_sem); |
361 | return retval; | |
362 | fail_nomem_policy: | |
363 | kmem_cache_free(vm_area_cachep, tmp); | |
364 | fail_nomem: | |
365 | retval = -ENOMEM; | |
366 | vm_unacct_memory(charge); | |
367 | goto out; | |
368 | } | |
369 | ||
370 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
371 | { | |
372 | mm->pgd = pgd_alloc(mm); | |
373 | if (unlikely(!mm->pgd)) | |
374 | return -ENOMEM; | |
375 | return 0; | |
376 | } | |
377 | ||
378 | static inline void mm_free_pgd(struct mm_struct * mm) | |
379 | { | |
5e541973 | 380 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
381 | } |
382 | #else | |
383 | #define dup_mmap(mm, oldmm) (0) | |
384 | #define mm_alloc_pgd(mm) (0) | |
385 | #define mm_free_pgd(mm) | |
386 | #endif /* CONFIG_MMU */ | |
387 | ||
23ff4440 | 388 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 389 | |
e94b1766 | 390 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
391 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
392 | ||
393 | #include <linux/init_task.h> | |
394 | ||
78fb7466 | 395 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
396 | { |
397 | atomic_set(&mm->mm_users, 1); | |
398 | atomic_set(&mm->mm_count, 1); | |
399 | init_rwsem(&mm->mmap_sem); | |
400 | INIT_LIST_HEAD(&mm->mmlist); | |
3cb4a0bb KH |
401 | mm->flags = (current->mm) ? current->mm->flags |
402 | : MMF_DUMP_FILTER_DEFAULT; | |
1da177e4 LT |
403 | mm->core_waiters = 0; |
404 | mm->nr_ptes = 0; | |
4294621f | 405 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 406 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
407 | spin_lock_init(&mm->page_table_lock); |
408 | rwlock_init(&mm->ioctx_list_lock); | |
409 | mm->ioctx_list = NULL; | |
1da177e4 | 410 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 411 | mm->cached_hole_size = ~0UL; |
cf475ad2 | 412 | mm_init_owner(mm, p); |
1da177e4 LT |
413 | |
414 | if (likely(!mm_alloc_pgd(mm))) { | |
415 | mm->def_flags = 0; | |
416 | return mm; | |
417 | } | |
78fb7466 | 418 | |
1da177e4 LT |
419 | free_mm(mm); |
420 | return NULL; | |
421 | } | |
422 | ||
423 | /* | |
424 | * Allocate and initialize an mm_struct. | |
425 | */ | |
426 | struct mm_struct * mm_alloc(void) | |
427 | { | |
428 | struct mm_struct * mm; | |
429 | ||
430 | mm = allocate_mm(); | |
431 | if (mm) { | |
432 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 433 | mm = mm_init(mm, current); |
1da177e4 LT |
434 | } |
435 | return mm; | |
436 | } | |
437 | ||
438 | /* | |
439 | * Called when the last reference to the mm | |
440 | * is dropped: either by a lazy thread or by | |
441 | * mmput. Free the page directory and the mm. | |
442 | */ | |
7ad5b3a5 | 443 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
444 | { |
445 | BUG_ON(mm == &init_mm); | |
446 | mm_free_pgd(mm); | |
447 | destroy_context(mm); | |
448 | free_mm(mm); | |
449 | } | |
6d4e4c4f | 450 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
451 | |
452 | /* | |
453 | * Decrement the use count and release all resources for an mm. | |
454 | */ | |
455 | void mmput(struct mm_struct *mm) | |
456 | { | |
0ae26f1b AM |
457 | might_sleep(); |
458 | ||
1da177e4 LT |
459 | if (atomic_dec_and_test(&mm->mm_users)) { |
460 | exit_aio(mm); | |
461 | exit_mmap(mm); | |
925d1c40 | 462 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
463 | if (!list_empty(&mm->mmlist)) { |
464 | spin_lock(&mmlist_lock); | |
465 | list_del(&mm->mmlist); | |
466 | spin_unlock(&mmlist_lock); | |
467 | } | |
468 | put_swap_token(mm); | |
469 | mmdrop(mm); | |
470 | } | |
471 | } | |
472 | EXPORT_SYMBOL_GPL(mmput); | |
473 | ||
474 | /** | |
475 | * get_task_mm - acquire a reference to the task's mm | |
476 | * | |
477 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning | |
478 | * this kernel workthread has transiently adopted a user mm with use_mm, | |
479 | * to do its AIO) is not set and if so returns a reference to it, after | |
480 | * bumping up the use count. User must release the mm via mmput() | |
481 | * after use. Typically used by /proc and ptrace. | |
482 | */ | |
483 | struct mm_struct *get_task_mm(struct task_struct *task) | |
484 | { | |
485 | struct mm_struct *mm; | |
486 | ||
487 | task_lock(task); | |
488 | mm = task->mm; | |
489 | if (mm) { | |
490 | if (task->flags & PF_BORROWED_MM) | |
491 | mm = NULL; | |
492 | else | |
493 | atomic_inc(&mm->mm_users); | |
494 | } | |
495 | task_unlock(task); | |
496 | return mm; | |
497 | } | |
498 | EXPORT_SYMBOL_GPL(get_task_mm); | |
499 | ||
500 | /* Please note the differences between mmput and mm_release. | |
501 | * mmput is called whenever we stop holding onto a mm_struct, | |
502 | * error success whatever. | |
503 | * | |
504 | * mm_release is called after a mm_struct has been removed | |
505 | * from the current process. | |
506 | * | |
507 | * This difference is important for error handling, when we | |
508 | * only half set up a mm_struct for a new process and need to restore | |
509 | * the old one. Because we mmput the new mm_struct before | |
510 | * restoring the old one. . . | |
511 | * Eric Biederman 10 January 1998 | |
512 | */ | |
513 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
514 | { | |
515 | struct completion *vfork_done = tsk->vfork_done; | |
516 | ||
517 | /* Get rid of any cached register state */ | |
518 | deactivate_mm(tsk, mm); | |
519 | ||
520 | /* notify parent sleeping on vfork() */ | |
521 | if (vfork_done) { | |
522 | tsk->vfork_done = NULL; | |
523 | complete(vfork_done); | |
524 | } | |
fec1d011 RM |
525 | |
526 | /* | |
527 | * If we're exiting normally, clear a user-space tid field if | |
528 | * requested. We leave this alone when dying by signal, to leave | |
529 | * the value intact in a core dump, and to save the unnecessary | |
530 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
531 | */ | |
532 | if (tsk->clear_child_tid | |
533 | && !(tsk->flags & PF_SIGNALED) | |
534 | && atomic_read(&mm->mm_users) > 1) { | |
1da177e4 LT |
535 | u32 __user * tidptr = tsk->clear_child_tid; |
536 | tsk->clear_child_tid = NULL; | |
537 | ||
538 | /* | |
539 | * We don't check the error code - if userspace has | |
540 | * not set up a proper pointer then tough luck. | |
541 | */ | |
542 | put_user(0, tidptr); | |
543 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
544 | } | |
545 | } | |
546 | ||
a0a7ec30 JD |
547 | /* |
548 | * Allocate a new mm structure and copy contents from the | |
549 | * mm structure of the passed in task structure. | |
550 | */ | |
402b0862 | 551 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
552 | { |
553 | struct mm_struct *mm, *oldmm = current->mm; | |
554 | int err; | |
555 | ||
556 | if (!oldmm) | |
557 | return NULL; | |
558 | ||
559 | mm = allocate_mm(); | |
560 | if (!mm) | |
561 | goto fail_nomem; | |
562 | ||
563 | memcpy(mm, oldmm, sizeof(*mm)); | |
564 | ||
7602bdf2 AC |
565 | /* Initializing for Swap token stuff */ |
566 | mm->token_priority = 0; | |
567 | mm->last_interval = 0; | |
568 | ||
78fb7466 | 569 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
570 | goto fail_nomem; |
571 | ||
572 | if (init_new_context(tsk, mm)) | |
573 | goto fail_nocontext; | |
574 | ||
925d1c40 MH |
575 | dup_mm_exe_file(oldmm, mm); |
576 | ||
a0a7ec30 JD |
577 | err = dup_mmap(mm, oldmm); |
578 | if (err) | |
579 | goto free_pt; | |
580 | ||
581 | mm->hiwater_rss = get_mm_rss(mm); | |
582 | mm->hiwater_vm = mm->total_vm; | |
583 | ||
584 | return mm; | |
585 | ||
586 | free_pt: | |
587 | mmput(mm); | |
588 | ||
589 | fail_nomem: | |
590 | return NULL; | |
591 | ||
592 | fail_nocontext: | |
593 | /* | |
594 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
595 | * because it calls destroy_context() | |
596 | */ | |
597 | mm_free_pgd(mm); | |
598 | free_mm(mm); | |
599 | return NULL; | |
600 | } | |
601 | ||
1da177e4 LT |
602 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
603 | { | |
604 | struct mm_struct * mm, *oldmm; | |
605 | int retval; | |
606 | ||
607 | tsk->min_flt = tsk->maj_flt = 0; | |
608 | tsk->nvcsw = tsk->nivcsw = 0; | |
609 | ||
610 | tsk->mm = NULL; | |
611 | tsk->active_mm = NULL; | |
612 | ||
613 | /* | |
614 | * Are we cloning a kernel thread? | |
615 | * | |
616 | * We need to steal a active VM for that.. | |
617 | */ | |
618 | oldmm = current->mm; | |
619 | if (!oldmm) | |
620 | return 0; | |
621 | ||
622 | if (clone_flags & CLONE_VM) { | |
623 | atomic_inc(&oldmm->mm_users); | |
624 | mm = oldmm; | |
1da177e4 LT |
625 | goto good_mm; |
626 | } | |
627 | ||
628 | retval = -ENOMEM; | |
a0a7ec30 | 629 | mm = dup_mm(tsk); |
1da177e4 LT |
630 | if (!mm) |
631 | goto fail_nomem; | |
632 | ||
1da177e4 | 633 | good_mm: |
7602bdf2 AC |
634 | /* Initializing for Swap token stuff */ |
635 | mm->token_priority = 0; | |
636 | mm->last_interval = 0; | |
637 | ||
1da177e4 LT |
638 | tsk->mm = mm; |
639 | tsk->active_mm = mm; | |
640 | return 0; | |
641 | ||
1da177e4 LT |
642 | fail_nomem: |
643 | return retval; | |
1da177e4 LT |
644 | } |
645 | ||
a39bc516 | 646 | static struct fs_struct *__copy_fs_struct(struct fs_struct *old) |
1da177e4 LT |
647 | { |
648 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
649 | /* We don't need to lock fs - think why ;-) */ | |
650 | if (fs) { | |
651 | atomic_set(&fs->count, 1); | |
652 | rwlock_init(&fs->lock); | |
653 | fs->umask = old->umask; | |
654 | read_lock(&old->lock); | |
6ac08c39 JB |
655 | fs->root = old->root; |
656 | path_get(&old->root); | |
657 | fs->pwd = old->pwd; | |
658 | path_get(&old->pwd); | |
659 | if (old->altroot.dentry) { | |
660 | fs->altroot = old->altroot; | |
661 | path_get(&old->altroot); | |
1da177e4 | 662 | } else { |
6ac08c39 JB |
663 | fs->altroot.mnt = NULL; |
664 | fs->altroot.dentry = NULL; | |
1da177e4 LT |
665 | } |
666 | read_unlock(&old->lock); | |
667 | } | |
668 | return fs; | |
669 | } | |
670 | ||
671 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
672 | { | |
673 | return __copy_fs_struct(old); | |
674 | } | |
675 | ||
676 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
677 | ||
a39bc516 | 678 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
679 | { |
680 | if (clone_flags & CLONE_FS) { | |
681 | atomic_inc(¤t->fs->count); | |
682 | return 0; | |
683 | } | |
684 | tsk->fs = __copy_fs_struct(current->fs); | |
685 | if (!tsk->fs) | |
686 | return -ENOMEM; | |
687 | return 0; | |
688 | } | |
689 | ||
a016f338 JD |
690 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
691 | { | |
692 | struct files_struct *oldf, *newf; | |
693 | int error = 0; | |
694 | ||
695 | /* | |
696 | * A background process may not have any files ... | |
697 | */ | |
698 | oldf = current->files; | |
699 | if (!oldf) | |
700 | goto out; | |
701 | ||
702 | if (clone_flags & CLONE_FILES) { | |
703 | atomic_inc(&oldf->count); | |
704 | goto out; | |
705 | } | |
706 | ||
a016f338 JD |
707 | newf = dup_fd(oldf, &error); |
708 | if (!newf) | |
709 | goto out; | |
710 | ||
711 | tsk->files = newf; | |
712 | error = 0; | |
713 | out: | |
714 | return error; | |
715 | } | |
716 | ||
fadad878 | 717 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
718 | { |
719 | #ifdef CONFIG_BLOCK | |
720 | struct io_context *ioc = current->io_context; | |
721 | ||
722 | if (!ioc) | |
723 | return 0; | |
fadad878 JA |
724 | /* |
725 | * Share io context with parent, if CLONE_IO is set | |
726 | */ | |
727 | if (clone_flags & CLONE_IO) { | |
728 | tsk->io_context = ioc_task_link(ioc); | |
729 | if (unlikely(!tsk->io_context)) | |
730 | return -ENOMEM; | |
731 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
732 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
733 | if (unlikely(!tsk->io_context)) | |
734 | return -ENOMEM; | |
735 | ||
fd0928df JA |
736 | tsk->io_context->ioprio = ioc->ioprio; |
737 | } | |
738 | #endif | |
739 | return 0; | |
740 | } | |
741 | ||
a39bc516 | 742 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
743 | { |
744 | struct sighand_struct *sig; | |
745 | ||
746 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
747 | atomic_inc(¤t->sighand->count); | |
748 | return 0; | |
749 | } | |
750 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 751 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
752 | if (!sig) |
753 | return -ENOMEM; | |
1da177e4 LT |
754 | atomic_set(&sig->count, 1); |
755 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
756 | return 0; | |
757 | } | |
758 | ||
a7e5328a | 759 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 760 | { |
c81addc9 ON |
761 | if (atomic_dec_and_test(&sighand->count)) |
762 | kmem_cache_free(sighand_cachep, sighand); | |
763 | } | |
764 | ||
a39bc516 | 765 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
766 | { |
767 | struct signal_struct *sig; | |
768 | int ret; | |
769 | ||
770 | if (clone_flags & CLONE_THREAD) { | |
771 | atomic_inc(¤t->signal->count); | |
772 | atomic_inc(¤t->signal->live); | |
773 | return 0; | |
774 | } | |
775 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
776 | tsk->signal = sig; | |
777 | if (!sig) | |
778 | return -ENOMEM; | |
779 | ||
780 | ret = copy_thread_group_keys(tsk); | |
781 | if (ret < 0) { | |
782 | kmem_cache_free(signal_cachep, sig); | |
783 | return ret; | |
784 | } | |
785 | ||
786 | atomic_set(&sig->count, 1); | |
787 | atomic_set(&sig->live, 1); | |
788 | init_waitqueue_head(&sig->wait_chldexit); | |
789 | sig->flags = 0; | |
790 | sig->group_exit_code = 0; | |
791 | sig->group_exit_task = NULL; | |
792 | sig->group_stop_count = 0; | |
db51aecc | 793 | sig->curr_target = tsk; |
1da177e4 LT |
794 | init_sigpending(&sig->shared_pending); |
795 | INIT_LIST_HEAD(&sig->posix_timers); | |
796 | ||
c9cb2e3d | 797 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
2ff678b8 | 798 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 799 | sig->real_timer.function = it_real_fn; |
1da177e4 LT |
800 | |
801 | sig->it_virt_expires = cputime_zero; | |
802 | sig->it_virt_incr = cputime_zero; | |
803 | sig->it_prof_expires = cputime_zero; | |
804 | sig->it_prof_incr = cputime_zero; | |
805 | ||
1da177e4 | 806 | sig->leader = 0; /* session leadership doesn't inherit */ |
ab521dc0 | 807 | sig->tty_old_pgrp = NULL; |
1da177e4 LT |
808 | |
809 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
9ac52315 LV |
810 | sig->gtime = cputime_zero; |
811 | sig->cgtime = cputime_zero; | |
1da177e4 LT |
812 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
813 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
6eaeeaba | 814 | sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; |
172ba844 | 815 | sig->sum_sched_runtime = 0; |
1da177e4 LT |
816 | INIT_LIST_HEAD(&sig->cpu_timers[0]); |
817 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
818 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
ad4ecbcb | 819 | taskstats_tgid_init(sig); |
1da177e4 LT |
820 | |
821 | task_lock(current->group_leader); | |
822 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
823 | task_unlock(current->group_leader); | |
824 | ||
825 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
826 | /* | |
827 | * New sole thread in the process gets an expiry time | |
828 | * of the whole CPU time limit. | |
829 | */ | |
830 | tsk->it_prof_expires = | |
831 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
832 | } | |
0e464814 | 833 | acct_init_pacct(&sig->pacct); |
1da177e4 | 834 | |
522ed776 MT |
835 | tty_audit_fork(sig); |
836 | ||
1da177e4 LT |
837 | return 0; |
838 | } | |
839 | ||
6b3934ef ON |
840 | void __cleanup_signal(struct signal_struct *sig) |
841 | { | |
842 | exit_thread_group_keys(sig); | |
843 | kmem_cache_free(signal_cachep, sig); | |
844 | } | |
845 | ||
a39bc516 | 846 | static void cleanup_signal(struct task_struct *tsk) |
6b3934ef ON |
847 | { |
848 | struct signal_struct *sig = tsk->signal; | |
849 | ||
850 | atomic_dec(&sig->live); | |
851 | ||
852 | if (atomic_dec_and_test(&sig->count)) | |
853 | __cleanup_signal(sig); | |
854 | } | |
855 | ||
a39bc516 | 856 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
857 | { |
858 | unsigned long new_flags = p->flags; | |
859 | ||
83144186 | 860 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 LT |
861 | new_flags |= PF_FORKNOEXEC; |
862 | if (!(clone_flags & CLONE_PTRACE)) | |
863 | p->ptrace = 0; | |
864 | p->flags = new_flags; | |
2e131895 | 865 | clear_freeze_flag(p); |
1da177e4 LT |
866 | } |
867 | ||
868 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
869 | { | |
870 | current->clear_child_tid = tidptr; | |
871 | ||
b488893a | 872 | return task_pid_vnr(current); |
1da177e4 LT |
873 | } |
874 | ||
a39bc516 | 875 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 876 | { |
23f78d4a | 877 | spin_lock_init(&p->pi_lock); |
e29e175b | 878 | #ifdef CONFIG_RT_MUTEXES |
23f78d4a IM |
879 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
880 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
881 | #endif |
882 | } | |
883 | ||
cf475ad2 BS |
884 | #ifdef CONFIG_MM_OWNER |
885 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
886 | { | |
887 | mm->owner = p; | |
888 | } | |
889 | #endif /* CONFIG_MM_OWNER */ | |
890 | ||
1da177e4 LT |
891 | /* |
892 | * This creates a new process as a copy of the old one, | |
893 | * but does not actually start it yet. | |
894 | * | |
895 | * It copies the registers, and all the appropriate | |
896 | * parts of the process environment (as per the clone | |
897 | * flags). The actual kick-off is left to the caller. | |
898 | */ | |
36c8b586 IM |
899 | static struct task_struct *copy_process(unsigned long clone_flags, |
900 | unsigned long stack_start, | |
901 | struct pt_regs *regs, | |
902 | unsigned long stack_size, | |
36c8b586 | 903 | int __user *child_tidptr, |
85868995 | 904 | struct pid *pid) |
1da177e4 LT |
905 | { |
906 | int retval; | |
a24efe62 | 907 | struct task_struct *p; |
b4f48b63 | 908 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
909 | |
910 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
911 | return ERR_PTR(-EINVAL); | |
912 | ||
913 | /* | |
914 | * Thread groups must share signals as well, and detached threads | |
915 | * can only be started up within the thread group. | |
916 | */ | |
917 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
918 | return ERR_PTR(-EINVAL); | |
919 | ||
920 | /* | |
921 | * Shared signal handlers imply shared VM. By way of the above, | |
922 | * thread groups also imply shared VM. Blocking this case allows | |
923 | * for various simplifications in other code. | |
924 | */ | |
925 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
926 | return ERR_PTR(-EINVAL); | |
927 | ||
928 | retval = security_task_create(clone_flags); | |
929 | if (retval) | |
930 | goto fork_out; | |
931 | ||
932 | retval = -ENOMEM; | |
933 | p = dup_task_struct(current); | |
934 | if (!p) | |
935 | goto fork_out; | |
936 | ||
bea493a0 PZ |
937 | rt_mutex_init_task(p); |
938 | ||
d12c1a37 | 939 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
940 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
941 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
942 | #endif | |
1da177e4 LT |
943 | retval = -EAGAIN; |
944 | if (atomic_read(&p->user->processes) >= | |
945 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
946 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
acce292c | 947 | p->user != current->nsproxy->user_ns->root_user) |
1da177e4 LT |
948 | goto bad_fork_free; |
949 | } | |
950 | ||
951 | atomic_inc(&p->user->__count); | |
952 | atomic_inc(&p->user->processes); | |
953 | get_group_info(p->group_info); | |
954 | ||
955 | /* | |
956 | * If multiple threads are within copy_process(), then this check | |
957 | * triggers too late. This doesn't hurt, the check is only there | |
958 | * to stop root fork bombs. | |
959 | */ | |
960 | if (nr_threads >= max_threads) | |
961 | goto bad_fork_cleanup_count; | |
962 | ||
a1261f54 | 963 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
964 | goto bad_fork_cleanup_count; |
965 | ||
966 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
967 | goto bad_fork_cleanup_put_domain; | |
968 | ||
969 | p->did_exec = 0; | |
ca74e92b | 970 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 971 | copy_flags(clone_flags, p); |
1da177e4 LT |
972 | INIT_LIST_HEAD(&p->children); |
973 | INIT_LIST_HEAD(&p->sibling); | |
e260be67 PM |
974 | #ifdef CONFIG_PREEMPT_RCU |
975 | p->rcu_read_lock_nesting = 0; | |
976 | p->rcu_flipctr_idx = 0; | |
977 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1da177e4 LT |
978 | p->vfork_done = NULL; |
979 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
980 | |
981 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
982 | init_sigpending(&p->pending); | |
983 | ||
984 | p->utime = cputime_zero; | |
985 | p->stime = cputime_zero; | |
9ac52315 | 986 | p->gtime = cputime_zero; |
c66f08be MN |
987 | p->utimescaled = cputime_zero; |
988 | p->stimescaled = cputime_zero; | |
73a2bcb0 | 989 | p->prev_utime = cputime_zero; |
9301899b | 990 | p->prev_stime = cputime_zero; |
172ba844 | 991 | |
82a1fcb9 IM |
992 | #ifdef CONFIG_DETECT_SOFTLOCKUP |
993 | p->last_switch_count = 0; | |
994 | p->last_switch_timestamp = 0; | |
995 | #endif | |
996 | ||
4b98d11b | 997 | #ifdef CONFIG_TASK_XACCT |
1da177e4 LT |
998 | p->rchar = 0; /* I/O counter: bytes read */ |
999 | p->wchar = 0; /* I/O counter: bytes written */ | |
1000 | p->syscr = 0; /* I/O counter: read syscalls */ | |
1001 | p->syscw = 0; /* I/O counter: write syscalls */ | |
4b98d11b | 1002 | #endif |
7c3ab738 | 1003 | task_io_accounting_init(p); |
1da177e4 LT |
1004 | acct_clear_integrals(p); |
1005 | ||
23ff4440 | 1006 | p->it_virt_expires = cputime_zero; |
1da177e4 | 1007 | p->it_prof_expires = cputime_zero; |
23ff4440 DW |
1008 | p->it_sched_expires = 0; |
1009 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1010 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1011 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1da177e4 LT |
1012 | |
1013 | p->lock_depth = -1; /* -1 = no lock */ | |
1014 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1015 | p->real_start_time = p->start_time; |
1016 | monotonic_to_bootbased(&p->real_start_time); | |
57c521ce | 1017 | #ifdef CONFIG_SECURITY |
1da177e4 | 1018 | p->security = NULL; |
57c521ce | 1019 | #endif |
3b7391de | 1020 | p->cap_bset = current->cap_bset; |
1da177e4 | 1021 | p->io_context = NULL; |
1da177e4 | 1022 | p->audit_context = NULL; |
b4f48b63 | 1023 | cgroup_fork(p); |
1da177e4 | 1024 | #ifdef CONFIG_NUMA |
846a16bf | 1025 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1026 | if (IS_ERR(p->mempolicy)) { |
1027 | retval = PTR_ERR(p->mempolicy); | |
1028 | p->mempolicy = NULL; | |
b4f48b63 | 1029 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1030 | } |
c61afb18 | 1031 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1032 | #endif |
de30a2b3 IM |
1033 | #ifdef CONFIG_TRACE_IRQFLAGS |
1034 | p->irq_events = 0; | |
b36e4758 RK |
1035 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1036 | p->hardirqs_enabled = 1; | |
1037 | #else | |
de30a2b3 | 1038 | p->hardirqs_enabled = 0; |
b36e4758 | 1039 | #endif |
de30a2b3 IM |
1040 | p->hardirq_enable_ip = 0; |
1041 | p->hardirq_enable_event = 0; | |
1042 | p->hardirq_disable_ip = _THIS_IP_; | |
1043 | p->hardirq_disable_event = 0; | |
1044 | p->softirqs_enabled = 1; | |
1045 | p->softirq_enable_ip = _THIS_IP_; | |
1046 | p->softirq_enable_event = 0; | |
1047 | p->softirq_disable_ip = 0; | |
1048 | p->softirq_disable_event = 0; | |
1049 | p->hardirq_context = 0; | |
1050 | p->softirq_context = 0; | |
1051 | #endif | |
fbb9ce95 IM |
1052 | #ifdef CONFIG_LOCKDEP |
1053 | p->lockdep_depth = 0; /* no locks held yet */ | |
1054 | p->curr_chain_key = 0; | |
1055 | p->lockdep_recursion = 0; | |
1056 | #endif | |
1da177e4 | 1057 | |
408894ee IM |
1058 | #ifdef CONFIG_DEBUG_MUTEXES |
1059 | p->blocked_on = NULL; /* not blocked yet */ | |
1060 | #endif | |
1061 | ||
3c90e6e9 SV |
1062 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1063 | sched_fork(p, clone_flags); | |
1064 | ||
1da177e4 LT |
1065 | if ((retval = security_task_alloc(p))) |
1066 | goto bad_fork_cleanup_policy; | |
1067 | if ((retval = audit_alloc(p))) | |
1068 | goto bad_fork_cleanup_security; | |
1069 | /* copy all the process information */ | |
1070 | if ((retval = copy_semundo(clone_flags, p))) | |
1071 | goto bad_fork_cleanup_audit; | |
1072 | if ((retval = copy_files(clone_flags, p))) | |
1073 | goto bad_fork_cleanup_semundo; | |
1074 | if ((retval = copy_fs(clone_flags, p))) | |
1075 | goto bad_fork_cleanup_files; | |
1076 | if ((retval = copy_sighand(clone_flags, p))) | |
1077 | goto bad_fork_cleanup_fs; | |
1078 | if ((retval = copy_signal(clone_flags, p))) | |
1079 | goto bad_fork_cleanup_sighand; | |
1080 | if ((retval = copy_mm(clone_flags, p))) | |
1081 | goto bad_fork_cleanup_signal; | |
1082 | if ((retval = copy_keys(clone_flags, p))) | |
1083 | goto bad_fork_cleanup_mm; | |
ab516013 | 1084 | if ((retval = copy_namespaces(clone_flags, p))) |
1da177e4 | 1085 | goto bad_fork_cleanup_keys; |
fadad878 | 1086 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1087 | goto bad_fork_cleanup_namespaces; |
1da177e4 LT |
1088 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); |
1089 | if (retval) | |
fd0928df | 1090 | goto bad_fork_cleanup_io; |
1da177e4 | 1091 | |
425fb2b4 PE |
1092 | if (pid != &init_struct_pid) { |
1093 | retval = -ENOMEM; | |
1094 | pid = alloc_pid(task_active_pid_ns(p)); | |
1095 | if (!pid) | |
fd0928df | 1096 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1097 | |
1098 | if (clone_flags & CLONE_NEWPID) { | |
1099 | retval = pid_ns_prepare_proc(task_active_pid_ns(p)); | |
1100 | if (retval < 0) | |
1101 | goto bad_fork_free_pid; | |
1102 | } | |
425fb2b4 PE |
1103 | } |
1104 | ||
1105 | p->pid = pid_nr(pid); | |
1106 | p->tgid = p->pid; | |
1107 | if (clone_flags & CLONE_THREAD) | |
1108 | p->tgid = current->tgid; | |
1109 | ||
e885dcde SH |
1110 | if (current->nsproxy != p->nsproxy) { |
1111 | retval = ns_cgroup_clone(p, pid); | |
1112 | if (retval) | |
1113 | goto bad_fork_free_pid; | |
1114 | } | |
1115 | ||
1da177e4 LT |
1116 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1117 | /* | |
1118 | * Clear TID on mm_release()? | |
1119 | */ | |
1120 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1121 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1122 | p->robust_list = NULL; |
1123 | #ifdef CONFIG_COMPAT | |
1124 | p->compat_robust_list = NULL; | |
1125 | #endif | |
c87e2837 IM |
1126 | INIT_LIST_HEAD(&p->pi_state_list); |
1127 | p->pi_state_cache = NULL; | |
42b2dd0a | 1128 | #endif |
f9a3879a GM |
1129 | /* |
1130 | * sigaltstack should be cleared when sharing the same VM | |
1131 | */ | |
1132 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1133 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1134 | ||
1da177e4 LT |
1135 | /* |
1136 | * Syscall tracing should be turned off in the child regardless | |
1137 | * of CLONE_PTRACE. | |
1138 | */ | |
1139 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1140 | #ifdef TIF_SYSCALL_EMU |
1141 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1142 | #endif | |
9745512c | 1143 | clear_all_latency_tracing(p); |
1da177e4 LT |
1144 | |
1145 | /* Our parent execution domain becomes current domain | |
1146 | These must match for thread signalling to apply */ | |
1da177e4 LT |
1147 | p->parent_exec_id = p->self_exec_id; |
1148 | ||
1149 | /* ok, now we should be set up.. */ | |
1150 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1151 | p->pdeath_signal = 0; | |
1152 | p->exit_state = 0; | |
1153 | ||
1da177e4 LT |
1154 | /* |
1155 | * Ok, make it visible to the rest of the system. | |
1156 | * We dont wake it up yet. | |
1157 | */ | |
1158 | p->group_leader = p; | |
47e65328 | 1159 | INIT_LIST_HEAD(&p->thread_group); |
f470021a RM |
1160 | INIT_LIST_HEAD(&p->ptrace_entry); |
1161 | INIT_LIST_HEAD(&p->ptraced); | |
1da177e4 | 1162 | |
b4f48b63 PM |
1163 | /* Now that the task is set up, run cgroup callbacks if |
1164 | * necessary. We need to run them before the task is visible | |
1165 | * on the tasklist. */ | |
1166 | cgroup_fork_callbacks(p); | |
1167 | cgroup_callbacks_done = 1; | |
1168 | ||
1da177e4 LT |
1169 | /* Need tasklist lock for parent etc handling! */ |
1170 | write_lock_irq(&tasklist_lock); | |
1171 | ||
1172 | /* | |
476d139c NP |
1173 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1174 | * not be changed, nor will its assigned CPU. | |
1175 | * | |
1176 | * The cpus_allowed mask of the parent may have changed after it was | |
1177 | * copied first time - so re-copy it here, then check the child's CPU | |
1178 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1179 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1180 | */ |
1181 | p->cpus_allowed = current->cpus_allowed; | |
6f505b16 | 1182 | p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed; |
26ff6ad9 SV |
1183 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1184 | !cpu_online(task_cpu(p)))) | |
476d139c | 1185 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1186 | |
1da177e4 LT |
1187 | /* CLONE_PARENT re-uses the old parent */ |
1188 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1189 | p->real_parent = current->real_parent; | |
1190 | else | |
1191 | p->real_parent = current; | |
1192 | p->parent = p->real_parent; | |
1193 | ||
3f17da69 | 1194 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1195 | |
1196 | /* | |
1197 | * Process group and session signals need to be delivered to just the | |
1198 | * parent before the fork or both the parent and the child after the | |
1199 | * fork. Restart if a signal comes in before we add the new process to | |
1200 | * it's process group. | |
1201 | * A fatal signal pending means that current will exit, so the new | |
1202 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1203 | */ | |
23ff4440 | 1204 | recalc_sigpending(); |
4a2c7a78 ON |
1205 | if (signal_pending(current)) { |
1206 | spin_unlock(¤t->sighand->siglock); | |
1207 | write_unlock_irq(&tasklist_lock); | |
1208 | retval = -ERESTARTNOINTR; | |
425fb2b4 | 1209 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1210 | } |
1211 | ||
1da177e4 | 1212 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1213 | p->group_leader = current->group_leader; |
47e65328 | 1214 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1215 | |
1da177e4 LT |
1216 | if (!cputime_eq(current->signal->it_virt_expires, |
1217 | cputime_zero) || | |
1218 | !cputime_eq(current->signal->it_prof_expires, | |
1219 | cputime_zero) || | |
1220 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1221 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1222 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1223 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1224 | /* | |
1225 | * Have child wake up on its first tick to check | |
1226 | * for process CPU timers. | |
1227 | */ | |
1228 | p->it_prof_expires = jiffies_to_cputime(1); | |
1229 | } | |
1da177e4 LT |
1230 | } |
1231 | ||
73b9ebfe | 1232 | if (likely(p->pid)) { |
f470021a | 1233 | list_add_tail(&p->sibling, &p->real_parent->children); |
73b9ebfe ON |
1234 | if (unlikely(p->ptrace & PT_PTRACED)) |
1235 | __ptrace_link(p, current->parent); | |
1236 | ||
1237 | if (thread_group_leader(p)) { | |
5cd17569 | 1238 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1239 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1240 | |
fea9d175 | 1241 | p->signal->leader_pid = pid; |
5cd17569 EB |
1242 | p->signal->tty = current->signal->tty; |
1243 | set_task_pgrp(p, task_pgrp_nr(current)); | |
1244 | set_task_session(p, task_session_nr(current)); | |
1245 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); | |
1246 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
5e85d4ab | 1247 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1248 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1249 | } |
85868995 | 1250 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1251 | nr_threads++; |
1da177e4 LT |
1252 | } |
1253 | ||
1da177e4 | 1254 | total_forks++; |
3f17da69 | 1255 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1256 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1257 | proc_fork_connector(p); |
817929ec | 1258 | cgroup_post_fork(p); |
1da177e4 LT |
1259 | return p; |
1260 | ||
425fb2b4 PE |
1261 | bad_fork_free_pid: |
1262 | if (pid != &init_struct_pid) | |
1263 | free_pid(pid); | |
fd0928df JA |
1264 | bad_fork_cleanup_io: |
1265 | put_io_context(p->io_context); | |
ab516013 | 1266 | bad_fork_cleanup_namespaces: |
444f378b | 1267 | exit_task_namespaces(p); |
1da177e4 LT |
1268 | bad_fork_cleanup_keys: |
1269 | exit_keys(p); | |
1270 | bad_fork_cleanup_mm: | |
1271 | if (p->mm) | |
1272 | mmput(p->mm); | |
1273 | bad_fork_cleanup_signal: | |
6b3934ef | 1274 | cleanup_signal(p); |
1da177e4 | 1275 | bad_fork_cleanup_sighand: |
a7e5328a | 1276 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1277 | bad_fork_cleanup_fs: |
1278 | exit_fs(p); /* blocking */ | |
1279 | bad_fork_cleanup_files: | |
1280 | exit_files(p); /* blocking */ | |
1281 | bad_fork_cleanup_semundo: | |
1282 | exit_sem(p); | |
1283 | bad_fork_cleanup_audit: | |
1284 | audit_free(p); | |
1285 | bad_fork_cleanup_security: | |
1286 | security_task_free(p); | |
1287 | bad_fork_cleanup_policy: | |
1288 | #ifdef CONFIG_NUMA | |
f0be3d32 | 1289 | mpol_put(p->mempolicy); |
b4f48b63 | 1290 | bad_fork_cleanup_cgroup: |
1da177e4 | 1291 | #endif |
b4f48b63 | 1292 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1293 | delayacct_tsk_free(p); |
1da177e4 LT |
1294 | if (p->binfmt) |
1295 | module_put(p->binfmt->module); | |
1296 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1297 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1298 | bad_fork_cleanup_count: |
1299 | put_group_info(p->group_info); | |
1300 | atomic_dec(&p->user->processes); | |
1301 | free_uid(p->user); | |
1302 | bad_fork_free: | |
1303 | free_task(p); | |
fe7d37d1 ON |
1304 | fork_out: |
1305 | return ERR_PTR(retval); | |
1da177e4 LT |
1306 | } |
1307 | ||
6b2fb3c6 | 1308 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1309 | { |
1310 | memset(regs, 0, sizeof(struct pt_regs)); | |
1311 | return regs; | |
1312 | } | |
1313 | ||
9abcf40b | 1314 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1315 | { |
36c8b586 | 1316 | struct task_struct *task; |
1da177e4 LT |
1317 | struct pt_regs regs; |
1318 | ||
30e49c26 | 1319 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
85868995 | 1320 | &init_struct_pid); |
753ca4f3 AM |
1321 | if (!IS_ERR(task)) |
1322 | init_idle(task, cpu); | |
73b9ebfe | 1323 | |
1da177e4 LT |
1324 | return task; |
1325 | } | |
1326 | ||
a39bc516 | 1327 | static int fork_traceflag(unsigned clone_flags) |
1da177e4 LT |
1328 | { |
1329 | if (clone_flags & CLONE_UNTRACED) | |
1330 | return 0; | |
1331 | else if (clone_flags & CLONE_VFORK) { | |
1332 | if (current->ptrace & PT_TRACE_VFORK) | |
1333 | return PTRACE_EVENT_VFORK; | |
1334 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1335 | if (current->ptrace & PT_TRACE_CLONE) | |
1336 | return PTRACE_EVENT_CLONE; | |
1337 | } else if (current->ptrace & PT_TRACE_FORK) | |
1338 | return PTRACE_EVENT_FORK; | |
1339 | ||
1340 | return 0; | |
1341 | } | |
1342 | ||
1343 | /* | |
1344 | * Ok, this is the main fork-routine. | |
1345 | * | |
1346 | * It copies the process, and if successful kick-starts | |
1347 | * it and waits for it to finish using the VM if required. | |
1348 | */ | |
1349 | long do_fork(unsigned long clone_flags, | |
1350 | unsigned long stack_start, | |
1351 | struct pt_regs *regs, | |
1352 | unsigned long stack_size, | |
1353 | int __user *parent_tidptr, | |
1354 | int __user *child_tidptr) | |
1355 | { | |
1356 | struct task_struct *p; | |
1357 | int trace = 0; | |
92476d7f | 1358 | long nr; |
1da177e4 | 1359 | |
bdff746a AM |
1360 | /* |
1361 | * We hope to recycle these flags after 2.6.26 | |
1362 | */ | |
1363 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1364 | static int __read_mostly count = 100; | |
1365 | ||
1366 | if (count > 0 && printk_ratelimit()) { | |
1367 | char comm[TASK_COMM_LEN]; | |
1368 | ||
1369 | count--; | |
1370 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1371 | "clone flags 0x%lx\n", | |
1372 | get_task_comm(comm, current), | |
1373 | clone_flags & CLONE_STOPPED); | |
1374 | } | |
1375 | } | |
1376 | ||
1da177e4 LT |
1377 | if (unlikely(current->ptrace)) { |
1378 | trace = fork_traceflag (clone_flags); | |
1379 | if (trace) | |
1380 | clone_flags |= CLONE_PTRACE; | |
1381 | } | |
1382 | ||
a6f5e063 | 1383 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
30e49c26 | 1384 | child_tidptr, NULL); |
1da177e4 LT |
1385 | /* |
1386 | * Do this prior waking up the new thread - the thread pointer | |
1387 | * might get invalid after that point, if the thread exits quickly. | |
1388 | */ | |
1389 | if (!IS_ERR(p)) { | |
1390 | struct completion vfork; | |
1391 | ||
6c5f3e7b | 1392 | nr = task_pid_vnr(p); |
30e49c26 PE |
1393 | |
1394 | if (clone_flags & CLONE_PARENT_SETTID) | |
1395 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1396 | |
1da177e4 LT |
1397 | if (clone_flags & CLONE_VFORK) { |
1398 | p->vfork_done = &vfork; | |
1399 | init_completion(&vfork); | |
1400 | } | |
1401 | ||
1402 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1403 | /* | |
1404 | * We'll start up with an immediate SIGSTOP. | |
1405 | */ | |
1406 | sigaddset(&p->pending.signal, SIGSTOP); | |
1407 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1408 | } | |
1409 | ||
1410 | if (!(clone_flags & CLONE_STOPPED)) | |
1411 | wake_up_new_task(p, clone_flags); | |
1412 | else | |
d9ae90ac | 1413 | __set_task_state(p, TASK_STOPPED); |
1da177e4 LT |
1414 | |
1415 | if (unlikely (trace)) { | |
92476d7f | 1416 | current->ptrace_message = nr; |
1da177e4 LT |
1417 | ptrace_notify ((trace << 8) | SIGTRAP); |
1418 | } | |
1419 | ||
1420 | if (clone_flags & CLONE_VFORK) { | |
ba96a0c8 | 1421 | freezer_do_not_count(); |
1da177e4 | 1422 | wait_for_completion(&vfork); |
ba96a0c8 | 1423 | freezer_count(); |
9f59ce5d CE |
1424 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) { |
1425 | current->ptrace_message = nr; | |
1da177e4 | 1426 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); |
9f59ce5d | 1427 | } |
1da177e4 LT |
1428 | } |
1429 | } else { | |
92476d7f | 1430 | nr = PTR_ERR(p); |
1da177e4 | 1431 | } |
92476d7f | 1432 | return nr; |
1da177e4 LT |
1433 | } |
1434 | ||
5fd63b30 RT |
1435 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1436 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1437 | #endif | |
1438 | ||
4ba9b9d0 | 1439 | static void sighand_ctor(struct kmem_cache *cachep, void *data) |
aa1757f9 ON |
1440 | { |
1441 | struct sighand_struct *sighand = data; | |
1442 | ||
a35afb83 | 1443 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1444 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1445 | } |
1446 | ||
1da177e4 LT |
1447 | void __init proc_caches_init(void) |
1448 | { | |
1449 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1450 | sizeof(struct sighand_struct), 0, | |
aa1757f9 | 1451 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
20c2df83 | 1452 | sighand_ctor); |
1da177e4 LT |
1453 | signal_cachep = kmem_cache_create("signal_cache", |
1454 | sizeof(struct signal_struct), 0, | |
20c2df83 PM |
1455 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1456 | files_cachep = kmem_cache_create("files_cache", | |
1da177e4 | 1457 | sizeof(struct files_struct), 0, |
20c2df83 PM |
1458 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1459 | fs_cachep = kmem_cache_create("fs_cache", | |
1da177e4 | 1460 | sizeof(struct fs_struct), 0, |
20c2df83 | 1461 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1462 | vm_area_cachep = kmem_cache_create("vm_area_struct", |
1463 | sizeof(struct vm_area_struct), 0, | |
20c2df83 | 1464 | SLAB_PANIC, NULL); |
1da177e4 | 1465 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1466 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
20c2df83 | 1467 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 1468 | } |
cf2e340f | 1469 | |
cf2e340f JD |
1470 | /* |
1471 | * Check constraints on flags passed to the unshare system call and | |
1472 | * force unsharing of additional process context as appropriate. | |
1473 | */ | |
a39bc516 | 1474 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1475 | { |
1476 | /* | |
1477 | * If unsharing a thread from a thread group, must also | |
1478 | * unshare vm. | |
1479 | */ | |
1480 | if (*flags_ptr & CLONE_THREAD) | |
1481 | *flags_ptr |= CLONE_VM; | |
1482 | ||
1483 | /* | |
1484 | * If unsharing vm, must also unshare signal handlers. | |
1485 | */ | |
1486 | if (*flags_ptr & CLONE_VM) | |
1487 | *flags_ptr |= CLONE_SIGHAND; | |
1488 | ||
1489 | /* | |
1490 | * If unsharing signal handlers and the task was created | |
1491 | * using CLONE_THREAD, then must unshare the thread | |
1492 | */ | |
1493 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1494 | (atomic_read(¤t->signal->count) > 1)) | |
1495 | *flags_ptr |= CLONE_THREAD; | |
1496 | ||
1497 | /* | |
1498 | * If unsharing namespace, must also unshare filesystem information. | |
1499 | */ | |
1500 | if (*flags_ptr & CLONE_NEWNS) | |
1501 | *flags_ptr |= CLONE_FS; | |
1502 | } | |
1503 | ||
1504 | /* | |
1505 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1506 | */ | |
1507 | static int unshare_thread(unsigned long unshare_flags) | |
1508 | { | |
1509 | if (unshare_flags & CLONE_THREAD) | |
1510 | return -EINVAL; | |
1511 | ||
1512 | return 0; | |
1513 | } | |
1514 | ||
1515 | /* | |
99d1419d | 1516 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1517 | */ |
1518 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1519 | { | |
1520 | struct fs_struct *fs = current->fs; | |
1521 | ||
1522 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1523 | (fs && atomic_read(&fs->count) > 1)) { |
1524 | *new_fsp = __copy_fs_struct(current->fs); | |
1525 | if (!*new_fsp) | |
1526 | return -ENOMEM; | |
1527 | } | |
cf2e340f JD |
1528 | |
1529 | return 0; | |
1530 | } | |
1531 | ||
cf2e340f | 1532 | /* |
dae3c5a0 | 1533 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1534 | */ |
1535 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1536 | { | |
1537 | struct sighand_struct *sigh = current->sighand; | |
1538 | ||
dae3c5a0 | 1539 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1540 | return -EINVAL; |
1541 | else | |
1542 | return 0; | |
1543 | } | |
1544 | ||
1545 | /* | |
a0a7ec30 | 1546 | * Unshare vm if it is being shared |
cf2e340f JD |
1547 | */ |
1548 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1549 | { | |
1550 | struct mm_struct *mm = current->mm; | |
1551 | ||
1552 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1553 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1554 | return -EINVAL; |
a0a7ec30 | 1555 | } |
cf2e340f JD |
1556 | |
1557 | return 0; | |
cf2e340f JD |
1558 | } |
1559 | ||
1560 | /* | |
a016f338 | 1561 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1562 | */ |
1563 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1564 | { | |
1565 | struct files_struct *fd = current->files; | |
a016f338 | 1566 | int error = 0; |
cf2e340f JD |
1567 | |
1568 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1569 | (fd && atomic_read(&fd->count) > 1)) { |
1570 | *new_fdp = dup_fd(fd, &error); | |
1571 | if (!*new_fdp) | |
1572 | return error; | |
1573 | } | |
cf2e340f JD |
1574 | |
1575 | return 0; | |
1576 | } | |
1577 | ||
cf2e340f JD |
1578 | /* |
1579 | * unshare allows a process to 'unshare' part of the process | |
1580 | * context which was originally shared using clone. copy_* | |
1581 | * functions used by do_fork() cannot be used here directly | |
1582 | * because they modify an inactive task_struct that is being | |
1583 | * constructed. Here we are modifying the current, active, | |
1584 | * task_struct. | |
1585 | */ | |
1586 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1587 | { | |
1588 | int err = 0; | |
1589 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1590 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1591 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1592 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1593 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1594 | int do_sysvsem = 0; |
cf2e340f JD |
1595 | |
1596 | check_unshare_flags(&unshare_flags); | |
1597 | ||
06f9d4f9 EB |
1598 | /* Return -EINVAL for all unsupported flags */ |
1599 | err = -EINVAL; | |
1600 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1601 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
9dd776b6 EB |
1602 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER| |
1603 | CLONE_NEWNET)) | |
06f9d4f9 EB |
1604 | goto bad_unshare_out; |
1605 | ||
6013f67f MS |
1606 | /* |
1607 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1608 | * to a new ipc namespace, the semaphore arrays from the old | |
1609 | * namespace are unreachable. | |
1610 | */ | |
1611 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1612 | do_sysvsem = 1; |
cf2e340f JD |
1613 | if ((err = unshare_thread(unshare_flags))) |
1614 | goto bad_unshare_out; | |
1615 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1616 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1617 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1618 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1619 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1620 | goto bad_unshare_cleanup_sigh; | |
1621 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1622 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1623 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1624 | new_fs))) | |
9edff4ab | 1625 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1626 | |
9edff4ab MS |
1627 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1628 | if (do_sysvsem) { | |
1629 | /* | |
1630 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1631 | */ | |
1632 | exit_sem(current); | |
1633 | } | |
ab516013 | 1634 | |
c0b2fc31 | 1635 | if (new_nsproxy) { |
cf7b708c PE |
1636 | switch_task_namespaces(current, new_nsproxy); |
1637 | new_nsproxy = NULL; | |
c0b2fc31 | 1638 | } |
cf2e340f | 1639 | |
cf7b708c PE |
1640 | task_lock(current); |
1641 | ||
cf2e340f JD |
1642 | if (new_fs) { |
1643 | fs = current->fs; | |
1644 | current->fs = new_fs; | |
1645 | new_fs = fs; | |
1646 | } | |
1647 | ||
cf2e340f JD |
1648 | if (new_mm) { |
1649 | mm = current->mm; | |
1650 | active_mm = current->active_mm; | |
1651 | current->mm = new_mm; | |
1652 | current->active_mm = new_mm; | |
1653 | activate_mm(active_mm, new_mm); | |
1654 | new_mm = mm; | |
1655 | } | |
1656 | ||
1657 | if (new_fd) { | |
1658 | fd = current->files; | |
1659 | current->files = new_fd; | |
1660 | new_fd = fd; | |
1661 | } | |
1662 | ||
1663 | task_unlock(current); | |
1664 | } | |
1665 | ||
c0b2fc31 | 1666 | if (new_nsproxy) |
444f378b | 1667 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1668 | |
cf2e340f JD |
1669 | bad_unshare_cleanup_fd: |
1670 | if (new_fd) | |
1671 | put_files_struct(new_fd); | |
1672 | ||
1673 | bad_unshare_cleanup_vm: | |
1674 | if (new_mm) | |
1675 | mmput(new_mm); | |
1676 | ||
1677 | bad_unshare_cleanup_sigh: | |
1678 | if (new_sigh) | |
1679 | if (atomic_dec_and_test(&new_sigh->count)) | |
1680 | kmem_cache_free(sighand_cachep, new_sigh); | |
1681 | ||
cf2e340f JD |
1682 | bad_unshare_cleanup_fs: |
1683 | if (new_fs) | |
1684 | put_fs_struct(new_fs); | |
1685 | ||
1686 | bad_unshare_cleanup_thread: | |
1687 | bad_unshare_out: | |
1688 | return err; | |
1689 | } | |
3b125388 AV |
1690 | |
1691 | /* | |
1692 | * Helper to unshare the files of the current task. | |
1693 | * We don't want to expose copy_files internals to | |
1694 | * the exec layer of the kernel. | |
1695 | */ | |
1696 | ||
1697 | int unshare_files(struct files_struct **displaced) | |
1698 | { | |
1699 | struct task_struct *task = current; | |
50704516 | 1700 | struct files_struct *copy = NULL; |
3b125388 AV |
1701 | int error; |
1702 | ||
1703 | error = unshare_fd(CLONE_FILES, ©); | |
1704 | if (error || !copy) { | |
1705 | *displaced = NULL; | |
1706 | return error; | |
1707 | } | |
1708 | *displaced = task->files; | |
1709 | task_lock(task); | |
1710 | task->files = copy; | |
1711 | task_unlock(task); | |
1712 | return 0; | |
1713 | } |