Commit | Line | Data |
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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 | ||
14 | #include <linux/config.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/unistd.h> | |
18 | #include <linux/smp_lock.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/vmalloc.h> | |
21 | #include <linux/completion.h> | |
22 | #include <linux/namespace.h> | |
23 | #include <linux/personality.h> | |
24 | #include <linux/mempolicy.h> | |
25 | #include <linux/sem.h> | |
26 | #include <linux/file.h> | |
27 | #include <linux/key.h> | |
28 | #include <linux/binfmts.h> | |
29 | #include <linux/mman.h> | |
30 | #include <linux/fs.h> | |
31 | #include <linux/cpu.h> | |
32 | #include <linux/cpuset.h> | |
33 | #include <linux/security.h> | |
34 | #include <linux/swap.h> | |
35 | #include <linux/syscalls.h> | |
36 | #include <linux/jiffies.h> | |
37 | #include <linux/futex.h> | |
ab2af1f5 | 38 | #include <linux/rcupdate.h> |
1da177e4 LT |
39 | #include <linux/ptrace.h> |
40 | #include <linux/mount.h> | |
41 | #include <linux/audit.h> | |
42 | #include <linux/profile.h> | |
43 | #include <linux/rmap.h> | |
44 | #include <linux/acct.h> | |
45 | ||
46 | #include <asm/pgtable.h> | |
47 | #include <asm/pgalloc.h> | |
48 | #include <asm/uaccess.h> | |
49 | #include <asm/mmu_context.h> | |
50 | #include <asm/cacheflush.h> | |
51 | #include <asm/tlbflush.h> | |
52 | ||
53 | /* | |
54 | * Protected counters by write_lock_irq(&tasklist_lock) | |
55 | */ | |
56 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
57 | int nr_threads; /* The idle threads do not count.. */ | |
58 | ||
59 | int max_threads; /* tunable limit on nr_threads */ | |
60 | ||
61 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
62 | ||
63 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ | |
64 | ||
65 | EXPORT_SYMBOL(tasklist_lock); | |
66 | ||
67 | int nr_processes(void) | |
68 | { | |
69 | int cpu; | |
70 | int total = 0; | |
71 | ||
72 | for_each_online_cpu(cpu) | |
73 | total += per_cpu(process_counts, cpu); | |
74 | ||
75 | return total; | |
76 | } | |
77 | ||
78 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
79 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
80 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
81 | static kmem_cache_t *task_struct_cachep; | |
82 | #endif | |
83 | ||
84 | /* SLAB cache for signal_struct structures (tsk->signal) */ | |
85 | kmem_cache_t *signal_cachep; | |
86 | ||
87 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
88 | kmem_cache_t *sighand_cachep; | |
89 | ||
90 | /* SLAB cache for files_struct structures (tsk->files) */ | |
91 | kmem_cache_t *files_cachep; | |
92 | ||
93 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
94 | kmem_cache_t *fs_cachep; | |
95 | ||
96 | /* SLAB cache for vm_area_struct structures */ | |
97 | kmem_cache_t *vm_area_cachep; | |
98 | ||
99 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
100 | static kmem_cache_t *mm_cachep; | |
101 | ||
102 | void free_task(struct task_struct *tsk) | |
103 | { | |
104 | free_thread_info(tsk->thread_info); | |
105 | free_task_struct(tsk); | |
106 | } | |
107 | EXPORT_SYMBOL(free_task); | |
108 | ||
109 | void __put_task_struct(struct task_struct *tsk) | |
110 | { | |
111 | WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE))); | |
112 | WARN_ON(atomic_read(&tsk->usage)); | |
113 | WARN_ON(tsk == current); | |
114 | ||
115 | if (unlikely(tsk->audit_context)) | |
116 | audit_free(tsk); | |
117 | security_task_free(tsk); | |
118 | free_uid(tsk->user); | |
119 | put_group_info(tsk->group_info); | |
120 | ||
121 | if (!profile_handoff_task(tsk)) | |
122 | free_task(tsk); | |
123 | } | |
124 | ||
125 | void __init fork_init(unsigned long mempages) | |
126 | { | |
127 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
128 | #ifndef ARCH_MIN_TASKALIGN | |
129 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
130 | #endif | |
131 | /* create a slab on which task_structs can be allocated */ | |
132 | task_struct_cachep = | |
133 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
134 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL); | |
135 | #endif | |
136 | ||
137 | /* | |
138 | * The default maximum number of threads is set to a safe | |
139 | * value: the thread structures can take up at most half | |
140 | * of memory. | |
141 | */ | |
142 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
143 | ||
144 | /* | |
145 | * we need to allow at least 20 threads to boot a system | |
146 | */ | |
147 | if(max_threads < 20) | |
148 | max_threads = 20; | |
149 | ||
150 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
151 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
152 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
153 | init_task.signal->rlim[RLIMIT_NPROC]; | |
154 | } | |
155 | ||
156 | static struct task_struct *dup_task_struct(struct task_struct *orig) | |
157 | { | |
158 | struct task_struct *tsk; | |
159 | struct thread_info *ti; | |
160 | ||
161 | prepare_to_copy(orig); | |
162 | ||
163 | tsk = alloc_task_struct(); | |
164 | if (!tsk) | |
165 | return NULL; | |
166 | ||
167 | ti = alloc_thread_info(tsk); | |
168 | if (!ti) { | |
169 | free_task_struct(tsk); | |
170 | return NULL; | |
171 | } | |
172 | ||
173 | *ti = *orig->thread_info; | |
174 | *tsk = *orig; | |
175 | tsk->thread_info = ti; | |
176 | ti->task = tsk; | |
177 | ||
178 | /* One for us, one for whoever does the "release_task()" (usually parent) */ | |
179 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 180 | atomic_set(&tsk->fs_excl, 0); |
1da177e4 LT |
181 | return tsk; |
182 | } | |
183 | ||
184 | #ifdef CONFIG_MMU | |
fd3e42fc | 185 | static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 186 | { |
fd3e42fc | 187 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
188 | struct rb_node **rb_link, *rb_parent; |
189 | int retval; | |
190 | unsigned long charge; | |
191 | struct mempolicy *pol; | |
192 | ||
193 | down_write(&oldmm->mmap_sem); | |
fd3e42fc | 194 | flush_cache_mm(oldmm); |
1da177e4 LT |
195 | mm->locked_vm = 0; |
196 | mm->mmap = NULL; | |
197 | mm->mmap_cache = NULL; | |
198 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 199 | mm->cached_hole_size = ~0UL; |
1da177e4 | 200 | mm->map_count = 0; |
1da177e4 LT |
201 | cpus_clear(mm->cpu_vm_mask); |
202 | mm->mm_rb = RB_ROOT; | |
203 | rb_link = &mm->mm_rb.rb_node; | |
204 | rb_parent = NULL; | |
205 | pprev = &mm->mmap; | |
206 | ||
fd3e42fc | 207 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
208 | struct file *file; |
209 | ||
210 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
211 | long pages = vma_pages(mpnt); |
212 | mm->total_vm -= pages; | |
ab50b8ed | 213 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 214 | -pages); |
1da177e4 LT |
215 | continue; |
216 | } | |
217 | charge = 0; | |
218 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
219 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
220 | if (security_vm_enough_memory(len)) | |
221 | goto fail_nomem; | |
222 | charge = len; | |
223 | } | |
224 | tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); | |
225 | if (!tmp) | |
226 | goto fail_nomem; | |
227 | *tmp = *mpnt; | |
228 | pol = mpol_copy(vma_policy(mpnt)); | |
229 | retval = PTR_ERR(pol); | |
230 | if (IS_ERR(pol)) | |
231 | goto fail_nomem_policy; | |
232 | vma_set_policy(tmp, pol); | |
233 | tmp->vm_flags &= ~VM_LOCKED; | |
234 | tmp->vm_mm = mm; | |
235 | tmp->vm_next = NULL; | |
236 | anon_vma_link(tmp); | |
237 | file = tmp->vm_file; | |
238 | if (file) { | |
239 | struct inode *inode = file->f_dentry->d_inode; | |
240 | get_file(file); | |
241 | if (tmp->vm_flags & VM_DENYWRITE) | |
242 | atomic_dec(&inode->i_writecount); | |
243 | ||
244 | /* insert tmp into the share list, just after mpnt */ | |
245 | spin_lock(&file->f_mapping->i_mmap_lock); | |
246 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
247 | flush_dcache_mmap_lock(file->f_mapping); | |
248 | vma_prio_tree_add(tmp, mpnt); | |
249 | flush_dcache_mmap_unlock(file->f_mapping); | |
250 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
251 | } | |
252 | ||
253 | /* | |
254 | * Link in the new vma and copy the page table entries: | |
45918e1a HD |
255 | * link in first so that swapoff can see swap entries. |
256 | * Note that, exceptionally, here the vma is inserted | |
257 | * without holding mm->mmap_sem. | |
1da177e4 LT |
258 | */ |
259 | spin_lock(&mm->page_table_lock); | |
260 | *pprev = tmp; | |
261 | pprev = &tmp->vm_next; | |
262 | ||
263 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
264 | rb_link = &tmp->vm_rb.rb_right; | |
265 | rb_parent = &tmp->vm_rb; | |
266 | ||
267 | mm->map_count++; | |
fd3e42fc | 268 | retval = copy_page_range(mm, oldmm, tmp); |
1da177e4 LT |
269 | spin_unlock(&mm->page_table_lock); |
270 | ||
271 | if (tmp->vm_ops && tmp->vm_ops->open) | |
272 | tmp->vm_ops->open(tmp); | |
273 | ||
274 | if (retval) | |
275 | goto out; | |
276 | } | |
277 | retval = 0; | |
278 | ||
279 | out: | |
fd3e42fc | 280 | flush_tlb_mm(oldmm); |
1da177e4 LT |
281 | up_write(&oldmm->mmap_sem); |
282 | return retval; | |
283 | fail_nomem_policy: | |
284 | kmem_cache_free(vm_area_cachep, tmp); | |
285 | fail_nomem: | |
286 | retval = -ENOMEM; | |
287 | vm_unacct_memory(charge); | |
288 | goto out; | |
289 | } | |
290 | ||
291 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
292 | { | |
293 | mm->pgd = pgd_alloc(mm); | |
294 | if (unlikely(!mm->pgd)) | |
295 | return -ENOMEM; | |
296 | return 0; | |
297 | } | |
298 | ||
299 | static inline void mm_free_pgd(struct mm_struct * mm) | |
300 | { | |
301 | pgd_free(mm->pgd); | |
302 | } | |
303 | #else | |
304 | #define dup_mmap(mm, oldmm) (0) | |
305 | #define mm_alloc_pgd(mm) (0) | |
306 | #define mm_free_pgd(mm) | |
307 | #endif /* CONFIG_MMU */ | |
308 | ||
309 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); | |
310 | ||
311 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL)) | |
312 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
313 | ||
314 | #include <linux/init_task.h> | |
315 | ||
316 | static struct mm_struct * mm_init(struct mm_struct * mm) | |
317 | { | |
318 | atomic_set(&mm->mm_users, 1); | |
319 | atomic_set(&mm->mm_count, 1); | |
320 | init_rwsem(&mm->mmap_sem); | |
321 | INIT_LIST_HEAD(&mm->mmlist); | |
322 | mm->core_waiters = 0; | |
323 | mm->nr_ptes = 0; | |
4294621f | 324 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 325 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
326 | spin_lock_init(&mm->page_table_lock); |
327 | rwlock_init(&mm->ioctx_list_lock); | |
328 | mm->ioctx_list = NULL; | |
329 | mm->default_kioctx = (struct kioctx)INIT_KIOCTX(mm->default_kioctx, *mm); | |
330 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
1363c3cd | 331 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
332 | |
333 | if (likely(!mm_alloc_pgd(mm))) { | |
334 | mm->def_flags = 0; | |
335 | return mm; | |
336 | } | |
337 | free_mm(mm); | |
338 | return NULL; | |
339 | } | |
340 | ||
341 | /* | |
342 | * Allocate and initialize an mm_struct. | |
343 | */ | |
344 | struct mm_struct * mm_alloc(void) | |
345 | { | |
346 | struct mm_struct * mm; | |
347 | ||
348 | mm = allocate_mm(); | |
349 | if (mm) { | |
350 | memset(mm, 0, sizeof(*mm)); | |
351 | mm = mm_init(mm); | |
352 | } | |
353 | return mm; | |
354 | } | |
355 | ||
356 | /* | |
357 | * Called when the last reference to the mm | |
358 | * is dropped: either by a lazy thread or by | |
359 | * mmput. Free the page directory and the mm. | |
360 | */ | |
361 | void fastcall __mmdrop(struct mm_struct *mm) | |
362 | { | |
363 | BUG_ON(mm == &init_mm); | |
364 | mm_free_pgd(mm); | |
365 | destroy_context(mm); | |
366 | free_mm(mm); | |
367 | } | |
368 | ||
369 | /* | |
370 | * Decrement the use count and release all resources for an mm. | |
371 | */ | |
372 | void mmput(struct mm_struct *mm) | |
373 | { | |
374 | if (atomic_dec_and_test(&mm->mm_users)) { | |
375 | exit_aio(mm); | |
376 | exit_mmap(mm); | |
377 | if (!list_empty(&mm->mmlist)) { | |
378 | spin_lock(&mmlist_lock); | |
379 | list_del(&mm->mmlist); | |
380 | spin_unlock(&mmlist_lock); | |
381 | } | |
382 | put_swap_token(mm); | |
383 | mmdrop(mm); | |
384 | } | |
385 | } | |
386 | EXPORT_SYMBOL_GPL(mmput); | |
387 | ||
388 | /** | |
389 | * get_task_mm - acquire a reference to the task's mm | |
390 | * | |
391 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning | |
392 | * this kernel workthread has transiently adopted a user mm with use_mm, | |
393 | * to do its AIO) is not set and if so returns a reference to it, after | |
394 | * bumping up the use count. User must release the mm via mmput() | |
395 | * after use. Typically used by /proc and ptrace. | |
396 | */ | |
397 | struct mm_struct *get_task_mm(struct task_struct *task) | |
398 | { | |
399 | struct mm_struct *mm; | |
400 | ||
401 | task_lock(task); | |
402 | mm = task->mm; | |
403 | if (mm) { | |
404 | if (task->flags & PF_BORROWED_MM) | |
405 | mm = NULL; | |
406 | else | |
407 | atomic_inc(&mm->mm_users); | |
408 | } | |
409 | task_unlock(task); | |
410 | return mm; | |
411 | } | |
412 | EXPORT_SYMBOL_GPL(get_task_mm); | |
413 | ||
414 | /* Please note the differences between mmput and mm_release. | |
415 | * mmput is called whenever we stop holding onto a mm_struct, | |
416 | * error success whatever. | |
417 | * | |
418 | * mm_release is called after a mm_struct has been removed | |
419 | * from the current process. | |
420 | * | |
421 | * This difference is important for error handling, when we | |
422 | * only half set up a mm_struct for a new process and need to restore | |
423 | * the old one. Because we mmput the new mm_struct before | |
424 | * restoring the old one. . . | |
425 | * Eric Biederman 10 January 1998 | |
426 | */ | |
427 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
428 | { | |
429 | struct completion *vfork_done = tsk->vfork_done; | |
430 | ||
431 | /* Get rid of any cached register state */ | |
432 | deactivate_mm(tsk, mm); | |
433 | ||
434 | /* notify parent sleeping on vfork() */ | |
435 | if (vfork_done) { | |
436 | tsk->vfork_done = NULL; | |
437 | complete(vfork_done); | |
438 | } | |
439 | if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) { | |
440 | u32 __user * tidptr = tsk->clear_child_tid; | |
441 | tsk->clear_child_tid = NULL; | |
442 | ||
443 | /* | |
444 | * We don't check the error code - if userspace has | |
445 | * not set up a proper pointer then tough luck. | |
446 | */ | |
447 | put_user(0, tidptr); | |
448 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
449 | } | |
450 | } | |
451 | ||
452 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) | |
453 | { | |
454 | struct mm_struct * mm, *oldmm; | |
455 | int retval; | |
456 | ||
457 | tsk->min_flt = tsk->maj_flt = 0; | |
458 | tsk->nvcsw = tsk->nivcsw = 0; | |
459 | ||
460 | tsk->mm = NULL; | |
461 | tsk->active_mm = NULL; | |
462 | ||
463 | /* | |
464 | * Are we cloning a kernel thread? | |
465 | * | |
466 | * We need to steal a active VM for that.. | |
467 | */ | |
468 | oldmm = current->mm; | |
469 | if (!oldmm) | |
470 | return 0; | |
471 | ||
472 | if (clone_flags & CLONE_VM) { | |
473 | atomic_inc(&oldmm->mm_users); | |
474 | mm = oldmm; | |
475 | /* | |
476 | * There are cases where the PTL is held to ensure no | |
477 | * new threads start up in user mode using an mm, which | |
478 | * allows optimizing out ipis; the tlb_gather_mmu code | |
479 | * is an example. | |
480 | */ | |
481 | spin_unlock_wait(&oldmm->page_table_lock); | |
482 | goto good_mm; | |
483 | } | |
484 | ||
485 | retval = -ENOMEM; | |
486 | mm = allocate_mm(); | |
487 | if (!mm) | |
488 | goto fail_nomem; | |
489 | ||
490 | /* Copy the current MM stuff.. */ | |
491 | memcpy(mm, oldmm, sizeof(*mm)); | |
492 | if (!mm_init(mm)) | |
493 | goto fail_nomem; | |
494 | ||
495 | if (init_new_context(tsk,mm)) | |
496 | goto fail_nocontext; | |
497 | ||
498 | retval = dup_mmap(mm, oldmm); | |
499 | if (retval) | |
500 | goto free_pt; | |
501 | ||
4294621f | 502 | mm->hiwater_rss = get_mm_rss(mm); |
1da177e4 LT |
503 | mm->hiwater_vm = mm->total_vm; |
504 | ||
505 | good_mm: | |
506 | tsk->mm = mm; | |
507 | tsk->active_mm = mm; | |
508 | return 0; | |
509 | ||
510 | free_pt: | |
511 | mmput(mm); | |
512 | fail_nomem: | |
513 | return retval; | |
514 | ||
515 | fail_nocontext: | |
516 | /* | |
517 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
518 | * because it calls destroy_context() | |
519 | */ | |
520 | mm_free_pgd(mm); | |
521 | free_mm(mm); | |
522 | return retval; | |
523 | } | |
524 | ||
525 | static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old) | |
526 | { | |
527 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
528 | /* We don't need to lock fs - think why ;-) */ | |
529 | if (fs) { | |
530 | atomic_set(&fs->count, 1); | |
531 | rwlock_init(&fs->lock); | |
532 | fs->umask = old->umask; | |
533 | read_lock(&old->lock); | |
534 | fs->rootmnt = mntget(old->rootmnt); | |
535 | fs->root = dget(old->root); | |
536 | fs->pwdmnt = mntget(old->pwdmnt); | |
537 | fs->pwd = dget(old->pwd); | |
538 | if (old->altroot) { | |
539 | fs->altrootmnt = mntget(old->altrootmnt); | |
540 | fs->altroot = dget(old->altroot); | |
541 | } else { | |
542 | fs->altrootmnt = NULL; | |
543 | fs->altroot = NULL; | |
544 | } | |
545 | read_unlock(&old->lock); | |
546 | } | |
547 | return fs; | |
548 | } | |
549 | ||
550 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
551 | { | |
552 | return __copy_fs_struct(old); | |
553 | } | |
554 | ||
555 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
556 | ||
557 | static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk) | |
558 | { | |
559 | if (clone_flags & CLONE_FS) { | |
560 | atomic_inc(¤t->fs->count); | |
561 | return 0; | |
562 | } | |
563 | tsk->fs = __copy_fs_struct(current->fs); | |
564 | if (!tsk->fs) | |
565 | return -ENOMEM; | |
566 | return 0; | |
567 | } | |
568 | ||
ab2af1f5 | 569 | static int count_open_files(struct fdtable *fdt) |
1da177e4 | 570 | { |
ab2af1f5 | 571 | int size = fdt->max_fdset; |
1da177e4 LT |
572 | int i; |
573 | ||
574 | /* Find the last open fd */ | |
575 | for (i = size/(8*sizeof(long)); i > 0; ) { | |
badf1662 | 576 | if (fdt->open_fds->fds_bits[--i]) |
1da177e4 LT |
577 | break; |
578 | } | |
579 | i = (i+1) * 8 * sizeof(long); | |
580 | return i; | |
581 | } | |
582 | ||
badf1662 DS |
583 | static struct files_struct *alloc_files(void) |
584 | { | |
585 | struct files_struct *newf; | |
586 | struct fdtable *fdt; | |
587 | ||
588 | newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL); | |
589 | if (!newf) | |
590 | goto out; | |
591 | ||
592 | atomic_set(&newf->count, 1); | |
593 | ||
594 | spin_lock_init(&newf->file_lock); | |
ab2af1f5 | 595 | fdt = &newf->fdtab; |
badf1662 DS |
596 | fdt->next_fd = 0; |
597 | fdt->max_fds = NR_OPEN_DEFAULT; | |
598 | fdt->max_fdset = __FD_SETSIZE; | |
599 | fdt->close_on_exec = &newf->close_on_exec_init; | |
600 | fdt->open_fds = &newf->open_fds_init; | |
601 | fdt->fd = &newf->fd_array[0]; | |
ab2af1f5 DS |
602 | INIT_RCU_HEAD(&fdt->rcu); |
603 | fdt->free_files = NULL; | |
604 | fdt->next = NULL; | |
605 | rcu_assign_pointer(newf->fdt, fdt); | |
badf1662 DS |
606 | out: |
607 | return newf; | |
608 | } | |
609 | ||
1da177e4 LT |
610 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
611 | { | |
612 | struct files_struct *oldf, *newf; | |
613 | struct file **old_fds, **new_fds; | |
614 | int open_files, size, i, error = 0, expand; | |
badf1662 | 615 | struct fdtable *old_fdt, *new_fdt; |
1da177e4 LT |
616 | |
617 | /* | |
618 | * A background process may not have any files ... | |
619 | */ | |
620 | oldf = current->files; | |
621 | if (!oldf) | |
622 | goto out; | |
623 | ||
624 | if (clone_flags & CLONE_FILES) { | |
625 | atomic_inc(&oldf->count); | |
626 | goto out; | |
627 | } | |
628 | ||
629 | /* | |
630 | * Note: we may be using current for both targets (See exec.c) | |
631 | * This works because we cache current->files (old) as oldf. Don't | |
632 | * break this. | |
633 | */ | |
634 | tsk->files = NULL; | |
635 | error = -ENOMEM; | |
badf1662 DS |
636 | newf = alloc_files(); |
637 | if (!newf) | |
1da177e4 LT |
638 | goto out; |
639 | ||
1da177e4 | 640 | spin_lock(&oldf->file_lock); |
badf1662 DS |
641 | old_fdt = files_fdtable(oldf); |
642 | new_fdt = files_fdtable(newf); | |
643 | size = old_fdt->max_fdset; | |
ab2af1f5 | 644 | open_files = count_open_files(old_fdt); |
1da177e4 LT |
645 | expand = 0; |
646 | ||
647 | /* | |
648 | * Check whether we need to allocate a larger fd array or fd set. | |
649 | * Note: we're not a clone task, so the open count won't change. | |
650 | */ | |
badf1662 DS |
651 | if (open_files > new_fdt->max_fdset) { |
652 | new_fdt->max_fdset = 0; | |
1da177e4 LT |
653 | expand = 1; |
654 | } | |
badf1662 DS |
655 | if (open_files > new_fdt->max_fds) { |
656 | new_fdt->max_fds = 0; | |
1da177e4 LT |
657 | expand = 1; |
658 | } | |
659 | ||
660 | /* if the old fdset gets grown now, we'll only copy up to "size" fds */ | |
661 | if (expand) { | |
662 | spin_unlock(&oldf->file_lock); | |
663 | spin_lock(&newf->file_lock); | |
664 | error = expand_files(newf, open_files-1); | |
665 | spin_unlock(&newf->file_lock); | |
666 | if (error < 0) | |
667 | goto out_release; | |
ab2af1f5 DS |
668 | new_fdt = files_fdtable(newf); |
669 | /* | |
670 | * Reacquire the oldf lock and a pointer to its fd table | |
671 | * who knows it may have a new bigger fd table. We need | |
672 | * the latest pointer. | |
673 | */ | |
1da177e4 | 674 | spin_lock(&oldf->file_lock); |
ab2af1f5 | 675 | old_fdt = files_fdtable(oldf); |
1da177e4 LT |
676 | } |
677 | ||
badf1662 DS |
678 | old_fds = old_fdt->fd; |
679 | new_fds = new_fdt->fd; | |
1da177e4 | 680 | |
badf1662 DS |
681 | memcpy(new_fdt->open_fds->fds_bits, old_fdt->open_fds->fds_bits, open_files/8); |
682 | memcpy(new_fdt->close_on_exec->fds_bits, old_fdt->close_on_exec->fds_bits, open_files/8); | |
1da177e4 LT |
683 | |
684 | for (i = open_files; i != 0; i--) { | |
685 | struct file *f = *old_fds++; | |
686 | if (f) { | |
687 | get_file(f); | |
688 | } else { | |
689 | /* | |
690 | * The fd may be claimed in the fd bitmap but not yet | |
691 | * instantiated in the files array if a sibling thread | |
692 | * is partway through open(). So make sure that this | |
693 | * fd is available to the new process. | |
694 | */ | |
badf1662 | 695 | FD_CLR(open_files - i, new_fdt->open_fds); |
1da177e4 | 696 | } |
ab2af1f5 | 697 | rcu_assign_pointer(*new_fds++, f); |
1da177e4 LT |
698 | } |
699 | spin_unlock(&oldf->file_lock); | |
700 | ||
701 | /* compute the remainder to be cleared */ | |
badf1662 | 702 | size = (new_fdt->max_fds - open_files) * sizeof(struct file *); |
1da177e4 LT |
703 | |
704 | /* This is long word aligned thus could use a optimized version */ | |
705 | memset(new_fds, 0, size); | |
706 | ||
badf1662 DS |
707 | if (new_fdt->max_fdset > open_files) { |
708 | int left = (new_fdt->max_fdset-open_files)/8; | |
1da177e4 LT |
709 | int start = open_files / (8 * sizeof(unsigned long)); |
710 | ||
badf1662 DS |
711 | memset(&new_fdt->open_fds->fds_bits[start], 0, left); |
712 | memset(&new_fdt->close_on_exec->fds_bits[start], 0, left); | |
1da177e4 LT |
713 | } |
714 | ||
715 | tsk->files = newf; | |
716 | error = 0; | |
717 | out: | |
718 | return error; | |
719 | ||
720 | out_release: | |
badf1662 DS |
721 | free_fdset (new_fdt->close_on_exec, new_fdt->max_fdset); |
722 | free_fdset (new_fdt->open_fds, new_fdt->max_fdset); | |
723 | free_fd_array(new_fdt->fd, new_fdt->max_fds); | |
1da177e4 LT |
724 | kmem_cache_free(files_cachep, newf); |
725 | goto out; | |
726 | } | |
727 | ||
728 | /* | |
729 | * Helper to unshare the files of the current task. | |
730 | * We don't want to expose copy_files internals to | |
731 | * the exec layer of the kernel. | |
732 | */ | |
733 | ||
734 | int unshare_files(void) | |
735 | { | |
736 | struct files_struct *files = current->files; | |
737 | int rc; | |
738 | ||
739 | if(!files) | |
740 | BUG(); | |
741 | ||
742 | /* This can race but the race causes us to copy when we don't | |
743 | need to and drop the copy */ | |
744 | if(atomic_read(&files->count) == 1) | |
745 | { | |
746 | atomic_inc(&files->count); | |
747 | return 0; | |
748 | } | |
749 | rc = copy_files(0, current); | |
750 | if(rc) | |
751 | current->files = files; | |
752 | return rc; | |
753 | } | |
754 | ||
755 | EXPORT_SYMBOL(unshare_files); | |
756 | ||
757 | static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk) | |
758 | { | |
759 | struct sighand_struct *sig; | |
760 | ||
761 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
762 | atomic_inc(¤t->sighand->count); | |
763 | return 0; | |
764 | } | |
765 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
766 | tsk->sighand = sig; | |
767 | if (!sig) | |
768 | return -ENOMEM; | |
769 | spin_lock_init(&sig->siglock); | |
770 | atomic_set(&sig->count, 1); | |
771 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
772 | return 0; | |
773 | } | |
774 | ||
775 | static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk) | |
776 | { | |
777 | struct signal_struct *sig; | |
778 | int ret; | |
779 | ||
780 | if (clone_flags & CLONE_THREAD) { | |
781 | atomic_inc(¤t->signal->count); | |
782 | atomic_inc(¤t->signal->live); | |
783 | return 0; | |
784 | } | |
785 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
786 | tsk->signal = sig; | |
787 | if (!sig) | |
788 | return -ENOMEM; | |
789 | ||
790 | ret = copy_thread_group_keys(tsk); | |
791 | if (ret < 0) { | |
792 | kmem_cache_free(signal_cachep, sig); | |
793 | return ret; | |
794 | } | |
795 | ||
796 | atomic_set(&sig->count, 1); | |
797 | atomic_set(&sig->live, 1); | |
798 | init_waitqueue_head(&sig->wait_chldexit); | |
799 | sig->flags = 0; | |
800 | sig->group_exit_code = 0; | |
801 | sig->group_exit_task = NULL; | |
802 | sig->group_stop_count = 0; | |
803 | sig->curr_target = NULL; | |
804 | init_sigpending(&sig->shared_pending); | |
805 | INIT_LIST_HEAD(&sig->posix_timers); | |
806 | ||
807 | sig->it_real_value = sig->it_real_incr = 0; | |
808 | sig->real_timer.function = it_real_fn; | |
809 | sig->real_timer.data = (unsigned long) tsk; | |
810 | init_timer(&sig->real_timer); | |
811 | ||
812 | sig->it_virt_expires = cputime_zero; | |
813 | sig->it_virt_incr = cputime_zero; | |
814 | sig->it_prof_expires = cputime_zero; | |
815 | sig->it_prof_incr = cputime_zero; | |
816 | ||
817 | sig->tty = current->signal->tty; | |
818 | sig->pgrp = process_group(current); | |
819 | sig->session = current->signal->session; | |
820 | sig->leader = 0; /* session leadership doesn't inherit */ | |
821 | sig->tty_old_pgrp = 0; | |
822 | ||
823 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
824 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; | |
825 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
826 | sig->sched_time = 0; | |
827 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
828 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
829 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
830 | ||
831 | task_lock(current->group_leader); | |
832 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
833 | task_unlock(current->group_leader); | |
834 | ||
835 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
836 | /* | |
837 | * New sole thread in the process gets an expiry time | |
838 | * of the whole CPU time limit. | |
839 | */ | |
840 | tsk->it_prof_expires = | |
841 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
842 | } | |
843 | ||
844 | return 0; | |
845 | } | |
846 | ||
847 | static inline void copy_flags(unsigned long clone_flags, struct task_struct *p) | |
848 | { | |
849 | unsigned long new_flags = p->flags; | |
850 | ||
d1209d04 | 851 | new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE); |
1da177e4 LT |
852 | new_flags |= PF_FORKNOEXEC; |
853 | if (!(clone_flags & CLONE_PTRACE)) | |
854 | p->ptrace = 0; | |
855 | p->flags = new_flags; | |
856 | } | |
857 | ||
858 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
859 | { | |
860 | current->clear_child_tid = tidptr; | |
861 | ||
862 | return current->pid; | |
863 | } | |
864 | ||
865 | /* | |
866 | * This creates a new process as a copy of the old one, | |
867 | * but does not actually start it yet. | |
868 | * | |
869 | * It copies the registers, and all the appropriate | |
870 | * parts of the process environment (as per the clone | |
871 | * flags). The actual kick-off is left to the caller. | |
872 | */ | |
873 | static task_t *copy_process(unsigned long clone_flags, | |
874 | unsigned long stack_start, | |
875 | struct pt_regs *regs, | |
876 | unsigned long stack_size, | |
877 | int __user *parent_tidptr, | |
878 | int __user *child_tidptr, | |
879 | int pid) | |
880 | { | |
881 | int retval; | |
882 | struct task_struct *p = NULL; | |
883 | ||
884 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
885 | return ERR_PTR(-EINVAL); | |
886 | ||
887 | /* | |
888 | * Thread groups must share signals as well, and detached threads | |
889 | * can only be started up within the thread group. | |
890 | */ | |
891 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
892 | return ERR_PTR(-EINVAL); | |
893 | ||
894 | /* | |
895 | * Shared signal handlers imply shared VM. By way of the above, | |
896 | * thread groups also imply shared VM. Blocking this case allows | |
897 | * for various simplifications in other code. | |
898 | */ | |
899 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
900 | return ERR_PTR(-EINVAL); | |
901 | ||
902 | retval = security_task_create(clone_flags); | |
903 | if (retval) | |
904 | goto fork_out; | |
905 | ||
906 | retval = -ENOMEM; | |
907 | p = dup_task_struct(current); | |
908 | if (!p) | |
909 | goto fork_out; | |
910 | ||
911 | retval = -EAGAIN; | |
912 | if (atomic_read(&p->user->processes) >= | |
913 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
914 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
915 | p->user != &root_user) | |
916 | goto bad_fork_free; | |
917 | } | |
918 | ||
919 | atomic_inc(&p->user->__count); | |
920 | atomic_inc(&p->user->processes); | |
921 | get_group_info(p->group_info); | |
922 | ||
923 | /* | |
924 | * If multiple threads are within copy_process(), then this check | |
925 | * triggers too late. This doesn't hurt, the check is only there | |
926 | * to stop root fork bombs. | |
927 | */ | |
928 | if (nr_threads >= max_threads) | |
929 | goto bad_fork_cleanup_count; | |
930 | ||
931 | if (!try_module_get(p->thread_info->exec_domain->module)) | |
932 | goto bad_fork_cleanup_count; | |
933 | ||
934 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
935 | goto bad_fork_cleanup_put_domain; | |
936 | ||
937 | p->did_exec = 0; | |
938 | copy_flags(clone_flags, p); | |
939 | p->pid = pid; | |
940 | retval = -EFAULT; | |
941 | if (clone_flags & CLONE_PARENT_SETTID) | |
942 | if (put_user(p->pid, parent_tidptr)) | |
943 | goto bad_fork_cleanup; | |
944 | ||
945 | p->proc_dentry = NULL; | |
946 | ||
947 | INIT_LIST_HEAD(&p->children); | |
948 | INIT_LIST_HEAD(&p->sibling); | |
949 | p->vfork_done = NULL; | |
950 | spin_lock_init(&p->alloc_lock); | |
951 | spin_lock_init(&p->proc_lock); | |
952 | ||
953 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
954 | init_sigpending(&p->pending); | |
955 | ||
956 | p->utime = cputime_zero; | |
957 | p->stime = cputime_zero; | |
958 | p->sched_time = 0; | |
959 | p->rchar = 0; /* I/O counter: bytes read */ | |
960 | p->wchar = 0; /* I/O counter: bytes written */ | |
961 | p->syscr = 0; /* I/O counter: read syscalls */ | |
962 | p->syscw = 0; /* I/O counter: write syscalls */ | |
963 | acct_clear_integrals(p); | |
964 | ||
965 | p->it_virt_expires = cputime_zero; | |
966 | p->it_prof_expires = cputime_zero; | |
967 | p->it_sched_expires = 0; | |
968 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
969 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
970 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
971 | ||
972 | p->lock_depth = -1; /* -1 = no lock */ | |
973 | do_posix_clock_monotonic_gettime(&p->start_time); | |
974 | p->security = NULL; | |
975 | p->io_context = NULL; | |
976 | p->io_wait = NULL; | |
977 | p->audit_context = NULL; | |
978 | #ifdef CONFIG_NUMA | |
979 | p->mempolicy = mpol_copy(p->mempolicy); | |
980 | if (IS_ERR(p->mempolicy)) { | |
981 | retval = PTR_ERR(p->mempolicy); | |
982 | p->mempolicy = NULL; | |
983 | goto bad_fork_cleanup; | |
984 | } | |
985 | #endif | |
986 | ||
987 | p->tgid = p->pid; | |
988 | if (clone_flags & CLONE_THREAD) | |
989 | p->tgid = current->tgid; | |
990 | ||
991 | if ((retval = security_task_alloc(p))) | |
992 | goto bad_fork_cleanup_policy; | |
993 | if ((retval = audit_alloc(p))) | |
994 | goto bad_fork_cleanup_security; | |
995 | /* copy all the process information */ | |
996 | if ((retval = copy_semundo(clone_flags, p))) | |
997 | goto bad_fork_cleanup_audit; | |
998 | if ((retval = copy_files(clone_flags, p))) | |
999 | goto bad_fork_cleanup_semundo; | |
1000 | if ((retval = copy_fs(clone_flags, p))) | |
1001 | goto bad_fork_cleanup_files; | |
1002 | if ((retval = copy_sighand(clone_flags, p))) | |
1003 | goto bad_fork_cleanup_fs; | |
1004 | if ((retval = copy_signal(clone_flags, p))) | |
1005 | goto bad_fork_cleanup_sighand; | |
1006 | if ((retval = copy_mm(clone_flags, p))) | |
1007 | goto bad_fork_cleanup_signal; | |
1008 | if ((retval = copy_keys(clone_flags, p))) | |
1009 | goto bad_fork_cleanup_mm; | |
1010 | if ((retval = copy_namespace(clone_flags, p))) | |
1011 | goto bad_fork_cleanup_keys; | |
1012 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); | |
1013 | if (retval) | |
1014 | goto bad_fork_cleanup_namespace; | |
1015 | ||
1016 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; | |
1017 | /* | |
1018 | * Clear TID on mm_release()? | |
1019 | */ | |
1020 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
1021 | ||
1022 | /* | |
1023 | * Syscall tracing should be turned off in the child regardless | |
1024 | * of CLONE_PTRACE. | |
1025 | */ | |
1026 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1027 | #ifdef TIF_SYSCALL_EMU |
1028 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1029 | #endif | |
1da177e4 LT |
1030 | |
1031 | /* Our parent execution domain becomes current domain | |
1032 | These must match for thread signalling to apply */ | |
1033 | ||
1034 | p->parent_exec_id = p->self_exec_id; | |
1035 | ||
1036 | /* ok, now we should be set up.. */ | |
1037 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1038 | p->pdeath_signal = 0; | |
1039 | p->exit_state = 0; | |
1040 | ||
1da177e4 LT |
1041 | /* |
1042 | * Ok, make it visible to the rest of the system. | |
1043 | * We dont wake it up yet. | |
1044 | */ | |
1045 | p->group_leader = p; | |
1046 | INIT_LIST_HEAD(&p->ptrace_children); | |
1047 | INIT_LIST_HEAD(&p->ptrace_list); | |
1048 | ||
476d139c NP |
1049 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1050 | sched_fork(p, clone_flags); | |
1051 | ||
1da177e4 LT |
1052 | /* Need tasklist lock for parent etc handling! */ |
1053 | write_lock_irq(&tasklist_lock); | |
1054 | ||
1055 | /* | |
476d139c NP |
1056 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1057 | * not be changed, nor will its assigned CPU. | |
1058 | * | |
1059 | * The cpus_allowed mask of the parent may have changed after it was | |
1060 | * copied first time - so re-copy it here, then check the child's CPU | |
1061 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1062 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1063 | */ |
1064 | p->cpus_allowed = current->cpus_allowed; | |
26ff6ad9 SV |
1065 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1066 | !cpu_online(task_cpu(p)))) | |
476d139c | 1067 | set_task_cpu(p, smp_processor_id()); |
1da177e4 LT |
1068 | |
1069 | /* | |
1070 | * Check for pending SIGKILL! The new thread should not be allowed | |
1071 | * to slip out of an OOM kill. (or normal SIGKILL.) | |
1072 | */ | |
1073 | if (sigismember(¤t->pending.signal, SIGKILL)) { | |
1074 | write_unlock_irq(&tasklist_lock); | |
1075 | retval = -EINTR; | |
1076 | goto bad_fork_cleanup_namespace; | |
1077 | } | |
1078 | ||
1079 | /* CLONE_PARENT re-uses the old parent */ | |
1080 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1081 | p->real_parent = current->real_parent; | |
1082 | else | |
1083 | p->real_parent = current; | |
1084 | p->parent = p->real_parent; | |
1085 | ||
1086 | if (clone_flags & CLONE_THREAD) { | |
1087 | spin_lock(¤t->sighand->siglock); | |
1088 | /* | |
1089 | * Important: if an exit-all has been started then | |
1090 | * do not create this new thread - the whole thread | |
1091 | * group is supposed to exit anyway. | |
1092 | */ | |
1093 | if (current->signal->flags & SIGNAL_GROUP_EXIT) { | |
1094 | spin_unlock(¤t->sighand->siglock); | |
1095 | write_unlock_irq(&tasklist_lock); | |
1096 | retval = -EAGAIN; | |
1097 | goto bad_fork_cleanup_namespace; | |
1098 | } | |
1099 | p->group_leader = current->group_leader; | |
1100 | ||
1101 | if (current->signal->group_stop_count > 0) { | |
1102 | /* | |
1103 | * There is an all-stop in progress for the group. | |
1104 | * We ourselves will stop as soon as we check signals. | |
1105 | * Make the new thread part of that group stop too. | |
1106 | */ | |
1107 | current->signal->group_stop_count++; | |
1108 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1109 | } | |
1110 | ||
1111 | if (!cputime_eq(current->signal->it_virt_expires, | |
1112 | cputime_zero) || | |
1113 | !cputime_eq(current->signal->it_prof_expires, | |
1114 | cputime_zero) || | |
1115 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1116 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1117 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1118 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1119 | /* | |
1120 | * Have child wake up on its first tick to check | |
1121 | * for process CPU timers. | |
1122 | */ | |
1123 | p->it_prof_expires = jiffies_to_cputime(1); | |
1124 | } | |
1125 | ||
1126 | spin_unlock(¤t->sighand->siglock); | |
1127 | } | |
1128 | ||
22e2c507 JA |
1129 | /* |
1130 | * inherit ioprio | |
1131 | */ | |
1132 | p->ioprio = current->ioprio; | |
1133 | ||
1da177e4 LT |
1134 | SET_LINKS(p); |
1135 | if (unlikely(p->ptrace & PT_PTRACED)) | |
1136 | __ptrace_link(p, current->parent); | |
1137 | ||
1138 | cpuset_fork(p); | |
1139 | ||
1140 | attach_pid(p, PIDTYPE_PID, p->pid); | |
1141 | attach_pid(p, PIDTYPE_TGID, p->tgid); | |
1142 | if (thread_group_leader(p)) { | |
1143 | attach_pid(p, PIDTYPE_PGID, process_group(p)); | |
1144 | attach_pid(p, PIDTYPE_SID, p->signal->session); | |
1145 | if (p->pid) | |
1146 | __get_cpu_var(process_counts)++; | |
1147 | } | |
1148 | ||
b0d62e6d JB |
1149 | if (!current->signal->tty && p->signal->tty) |
1150 | p->signal->tty = NULL; | |
1151 | ||
1da177e4 LT |
1152 | nr_threads++; |
1153 | total_forks++; | |
1154 | write_unlock_irq(&tasklist_lock); | |
1155 | retval = 0; | |
1156 | ||
1157 | fork_out: | |
1158 | if (retval) | |
1159 | return ERR_PTR(retval); | |
1160 | return p; | |
1161 | ||
1162 | bad_fork_cleanup_namespace: | |
1163 | exit_namespace(p); | |
1164 | bad_fork_cleanup_keys: | |
1165 | exit_keys(p); | |
1166 | bad_fork_cleanup_mm: | |
1167 | if (p->mm) | |
1168 | mmput(p->mm); | |
1169 | bad_fork_cleanup_signal: | |
1170 | exit_signal(p); | |
1171 | bad_fork_cleanup_sighand: | |
1172 | exit_sighand(p); | |
1173 | bad_fork_cleanup_fs: | |
1174 | exit_fs(p); /* blocking */ | |
1175 | bad_fork_cleanup_files: | |
1176 | exit_files(p); /* blocking */ | |
1177 | bad_fork_cleanup_semundo: | |
1178 | exit_sem(p); | |
1179 | bad_fork_cleanup_audit: | |
1180 | audit_free(p); | |
1181 | bad_fork_cleanup_security: | |
1182 | security_task_free(p); | |
1183 | bad_fork_cleanup_policy: | |
1184 | #ifdef CONFIG_NUMA | |
1185 | mpol_free(p->mempolicy); | |
1186 | #endif | |
1187 | bad_fork_cleanup: | |
1188 | if (p->binfmt) | |
1189 | module_put(p->binfmt->module); | |
1190 | bad_fork_cleanup_put_domain: | |
1191 | module_put(p->thread_info->exec_domain->module); | |
1192 | bad_fork_cleanup_count: | |
1193 | put_group_info(p->group_info); | |
1194 | atomic_dec(&p->user->processes); | |
1195 | free_uid(p->user); | |
1196 | bad_fork_free: | |
1197 | free_task(p); | |
1198 | goto fork_out; | |
1199 | } | |
1200 | ||
1201 | struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs) | |
1202 | { | |
1203 | memset(regs, 0, sizeof(struct pt_regs)); | |
1204 | return regs; | |
1205 | } | |
1206 | ||
1207 | task_t * __devinit fork_idle(int cpu) | |
1208 | { | |
1209 | task_t *task; | |
1210 | struct pt_regs regs; | |
1211 | ||
1212 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0); | |
1213 | if (!task) | |
1214 | return ERR_PTR(-ENOMEM); | |
1215 | init_idle(task, cpu); | |
1216 | unhash_process(task); | |
1217 | return task; | |
1218 | } | |
1219 | ||
1220 | static inline int fork_traceflag (unsigned clone_flags) | |
1221 | { | |
1222 | if (clone_flags & CLONE_UNTRACED) | |
1223 | return 0; | |
1224 | else if (clone_flags & CLONE_VFORK) { | |
1225 | if (current->ptrace & PT_TRACE_VFORK) | |
1226 | return PTRACE_EVENT_VFORK; | |
1227 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1228 | if (current->ptrace & PT_TRACE_CLONE) | |
1229 | return PTRACE_EVENT_CLONE; | |
1230 | } else if (current->ptrace & PT_TRACE_FORK) | |
1231 | return PTRACE_EVENT_FORK; | |
1232 | ||
1233 | return 0; | |
1234 | } | |
1235 | ||
1236 | /* | |
1237 | * Ok, this is the main fork-routine. | |
1238 | * | |
1239 | * It copies the process, and if successful kick-starts | |
1240 | * it and waits for it to finish using the VM if required. | |
1241 | */ | |
1242 | long do_fork(unsigned long clone_flags, | |
1243 | unsigned long stack_start, | |
1244 | struct pt_regs *regs, | |
1245 | unsigned long stack_size, | |
1246 | int __user *parent_tidptr, | |
1247 | int __user *child_tidptr) | |
1248 | { | |
1249 | struct task_struct *p; | |
1250 | int trace = 0; | |
1251 | long pid = alloc_pidmap(); | |
1252 | ||
1253 | if (pid < 0) | |
1254 | return -EAGAIN; | |
1255 | if (unlikely(current->ptrace)) { | |
1256 | trace = fork_traceflag (clone_flags); | |
1257 | if (trace) | |
1258 | clone_flags |= CLONE_PTRACE; | |
1259 | } | |
1260 | ||
1261 | p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid); | |
1262 | /* | |
1263 | * Do this prior waking up the new thread - the thread pointer | |
1264 | * might get invalid after that point, if the thread exits quickly. | |
1265 | */ | |
1266 | if (!IS_ERR(p)) { | |
1267 | struct completion vfork; | |
1268 | ||
1269 | if (clone_flags & CLONE_VFORK) { | |
1270 | p->vfork_done = &vfork; | |
1271 | init_completion(&vfork); | |
1272 | } | |
1273 | ||
1274 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1275 | /* | |
1276 | * We'll start up with an immediate SIGSTOP. | |
1277 | */ | |
1278 | sigaddset(&p->pending.signal, SIGSTOP); | |
1279 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1280 | } | |
1281 | ||
1282 | if (!(clone_flags & CLONE_STOPPED)) | |
1283 | wake_up_new_task(p, clone_flags); | |
1284 | else | |
1285 | p->state = TASK_STOPPED; | |
1286 | ||
1287 | if (unlikely (trace)) { | |
1288 | current->ptrace_message = pid; | |
1289 | ptrace_notify ((trace << 8) | SIGTRAP); | |
1290 | } | |
1291 | ||
1292 | if (clone_flags & CLONE_VFORK) { | |
1293 | wait_for_completion(&vfork); | |
1294 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) | |
1295 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); | |
1296 | } | |
1297 | } else { | |
1298 | free_pidmap(pid); | |
1299 | pid = PTR_ERR(p); | |
1300 | } | |
1301 | return pid; | |
1302 | } | |
1303 | ||
1304 | void __init proc_caches_init(void) | |
1305 | { | |
1306 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1307 | sizeof(struct sighand_struct), 0, | |
1308 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1309 | signal_cachep = kmem_cache_create("signal_cache", | |
1310 | sizeof(struct signal_struct), 0, | |
1311 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1312 | files_cachep = kmem_cache_create("files_cache", | |
1313 | sizeof(struct files_struct), 0, | |
1314 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1315 | fs_cachep = kmem_cache_create("fs_cache", | |
1316 | sizeof(struct fs_struct), 0, | |
1317 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1318 | vm_area_cachep = kmem_cache_create("vm_area_struct", | |
1319 | sizeof(struct vm_area_struct), 0, | |
1320 | SLAB_PANIC, NULL, NULL); | |
1321 | mm_cachep = kmem_cache_create("mm_struct", | |
1322 | sizeof(struct mm_struct), 0, | |
1323 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1324 | } |