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> | |
c59ede7b | 31 | #include <linux/capability.h> |
1da177e4 LT |
32 | #include <linux/cpu.h> |
33 | #include <linux/cpuset.h> | |
34 | #include <linux/security.h> | |
35 | #include <linux/swap.h> | |
36 | #include <linux/syscalls.h> | |
37 | #include <linux/jiffies.h> | |
38 | #include <linux/futex.h> | |
ab2af1f5 | 39 | #include <linux/rcupdate.h> |
1da177e4 LT |
40 | #include <linux/ptrace.h> |
41 | #include <linux/mount.h> | |
42 | #include <linux/audit.h> | |
43 | #include <linux/profile.h> | |
44 | #include <linux/rmap.h> | |
45 | #include <linux/acct.h> | |
9f46080c | 46 | #include <linux/cn_proc.h> |
1da177e4 LT |
47 | |
48 | #include <asm/pgtable.h> | |
49 | #include <asm/pgalloc.h> | |
50 | #include <asm/uaccess.h> | |
51 | #include <asm/mmu_context.h> | |
52 | #include <asm/cacheflush.h> | |
53 | #include <asm/tlbflush.h> | |
54 | ||
55 | /* | |
56 | * Protected counters by write_lock_irq(&tasklist_lock) | |
57 | */ | |
58 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
59 | int nr_threads; /* The idle threads do not count.. */ | |
60 | ||
61 | int max_threads; /* tunable limit on nr_threads */ | |
62 | ||
63 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
64 | ||
65 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ | |
66 | ||
67 | EXPORT_SYMBOL(tasklist_lock); | |
68 | ||
69 | int nr_processes(void) | |
70 | { | |
71 | int cpu; | |
72 | int total = 0; | |
73 | ||
74 | for_each_online_cpu(cpu) | |
75 | total += per_cpu(process_counts, cpu); | |
76 | ||
77 | return total; | |
78 | } | |
79 | ||
80 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
81 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
82 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
83 | static kmem_cache_t *task_struct_cachep; | |
84 | #endif | |
85 | ||
86 | /* SLAB cache for signal_struct structures (tsk->signal) */ | |
6b3934ef | 87 | static kmem_cache_t *signal_cachep; |
1da177e4 LT |
88 | |
89 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
90 | kmem_cache_t *sighand_cachep; | |
91 | ||
92 | /* SLAB cache for files_struct structures (tsk->files) */ | |
93 | kmem_cache_t *files_cachep; | |
94 | ||
95 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
96 | kmem_cache_t *fs_cachep; | |
97 | ||
98 | /* SLAB cache for vm_area_struct structures */ | |
99 | kmem_cache_t *vm_area_cachep; | |
100 | ||
101 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
102 | static kmem_cache_t *mm_cachep; | |
103 | ||
104 | void free_task(struct task_struct *tsk) | |
105 | { | |
106 | free_thread_info(tsk->thread_info); | |
107 | free_task_struct(tsk); | |
108 | } | |
109 | EXPORT_SYMBOL(free_task); | |
110 | ||
7cd9013b | 111 | void __put_task_struct_cb(struct rcu_head *rhp) |
1da177e4 | 112 | { |
7cd9013b CH |
113 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); |
114 | ||
1da177e4 LT |
115 | WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE))); |
116 | WARN_ON(atomic_read(&tsk->usage)); | |
117 | WARN_ON(tsk == current); | |
118 | ||
119 | if (unlikely(tsk->audit_context)) | |
120 | audit_free(tsk); | |
121 | security_task_free(tsk); | |
122 | free_uid(tsk->user); | |
123 | put_group_info(tsk->group_info); | |
124 | ||
125 | if (!profile_handoff_task(tsk)) | |
126 | free_task(tsk); | |
127 | } | |
128 | ||
129 | void __init fork_init(unsigned long mempages) | |
130 | { | |
131 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
132 | #ifndef ARCH_MIN_TASKALIGN | |
133 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
134 | #endif | |
135 | /* create a slab on which task_structs can be allocated */ | |
136 | task_struct_cachep = | |
137 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
138 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL); | |
139 | #endif | |
140 | ||
141 | /* | |
142 | * The default maximum number of threads is set to a safe | |
143 | * value: the thread structures can take up at most half | |
144 | * of memory. | |
145 | */ | |
146 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
147 | ||
148 | /* | |
149 | * we need to allow at least 20 threads to boot a system | |
150 | */ | |
151 | if(max_threads < 20) | |
152 | max_threads = 20; | |
153 | ||
154 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
155 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
156 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
157 | init_task.signal->rlim[RLIMIT_NPROC]; | |
158 | } | |
159 | ||
160 | static struct task_struct *dup_task_struct(struct task_struct *orig) | |
161 | { | |
162 | struct task_struct *tsk; | |
163 | struct thread_info *ti; | |
164 | ||
165 | prepare_to_copy(orig); | |
166 | ||
167 | tsk = alloc_task_struct(); | |
168 | if (!tsk) | |
169 | return NULL; | |
170 | ||
171 | ti = alloc_thread_info(tsk); | |
172 | if (!ti) { | |
173 | free_task_struct(tsk); | |
174 | return NULL; | |
175 | } | |
176 | ||
1da177e4 LT |
177 | *tsk = *orig; |
178 | tsk->thread_info = ti; | |
10ebffde | 179 | setup_thread_stack(tsk, orig); |
1da177e4 LT |
180 | |
181 | /* One for us, one for whoever does the "release_task()" (usually parent) */ | |
182 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 183 | atomic_set(&tsk->fs_excl, 0); |
2056a782 | 184 | tsk->btrace_seq = 0; |
1da177e4 LT |
185 | return tsk; |
186 | } | |
187 | ||
188 | #ifdef CONFIG_MMU | |
fd3e42fc | 189 | static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 190 | { |
fd3e42fc | 191 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
192 | struct rb_node **rb_link, *rb_parent; |
193 | int retval; | |
194 | unsigned long charge; | |
195 | struct mempolicy *pol; | |
196 | ||
197 | down_write(&oldmm->mmap_sem); | |
fd3e42fc | 198 | flush_cache_mm(oldmm); |
7ee78232 HD |
199 | down_write(&mm->mmap_sem); |
200 | ||
1da177e4 LT |
201 | mm->locked_vm = 0; |
202 | mm->mmap = NULL; | |
203 | mm->mmap_cache = NULL; | |
204 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 205 | mm->cached_hole_size = ~0UL; |
1da177e4 | 206 | mm->map_count = 0; |
1da177e4 LT |
207 | cpus_clear(mm->cpu_vm_mask); |
208 | mm->mm_rb = RB_ROOT; | |
209 | rb_link = &mm->mm_rb.rb_node; | |
210 | rb_parent = NULL; | |
211 | pprev = &mm->mmap; | |
212 | ||
fd3e42fc | 213 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
214 | struct file *file; |
215 | ||
216 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
217 | long pages = vma_pages(mpnt); |
218 | mm->total_vm -= pages; | |
ab50b8ed | 219 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 220 | -pages); |
1da177e4 LT |
221 | continue; |
222 | } | |
223 | charge = 0; | |
224 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
225 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
226 | if (security_vm_enough_memory(len)) | |
227 | goto fail_nomem; | |
228 | charge = len; | |
229 | } | |
230 | tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); | |
231 | if (!tmp) | |
232 | goto fail_nomem; | |
233 | *tmp = *mpnt; | |
234 | pol = mpol_copy(vma_policy(mpnt)); | |
235 | retval = PTR_ERR(pol); | |
236 | if (IS_ERR(pol)) | |
237 | goto fail_nomem_policy; | |
238 | vma_set_policy(tmp, pol); | |
239 | tmp->vm_flags &= ~VM_LOCKED; | |
240 | tmp->vm_mm = mm; | |
241 | tmp->vm_next = NULL; | |
242 | anon_vma_link(tmp); | |
243 | file = tmp->vm_file; | |
244 | if (file) { | |
245 | struct inode *inode = file->f_dentry->d_inode; | |
246 | get_file(file); | |
247 | if (tmp->vm_flags & VM_DENYWRITE) | |
248 | atomic_dec(&inode->i_writecount); | |
249 | ||
250 | /* insert tmp into the share list, just after mpnt */ | |
251 | spin_lock(&file->f_mapping->i_mmap_lock); | |
252 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
253 | flush_dcache_mmap_lock(file->f_mapping); | |
254 | vma_prio_tree_add(tmp, mpnt); | |
255 | flush_dcache_mmap_unlock(file->f_mapping); | |
256 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
257 | } | |
258 | ||
259 | /* | |
7ee78232 | 260 | * Link in the new vma and copy the page table entries. |
1da177e4 | 261 | */ |
1da177e4 LT |
262 | *pprev = tmp; |
263 | pprev = &tmp->vm_next; | |
264 | ||
265 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
266 | rb_link = &tmp->vm_rb.rb_right; | |
267 | rb_parent = &tmp->vm_rb; | |
268 | ||
269 | mm->map_count++; | |
0b0db14c | 270 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
271 | |
272 | if (tmp->vm_ops && tmp->vm_ops->open) | |
273 | tmp->vm_ops->open(tmp); | |
274 | ||
275 | if (retval) | |
276 | goto out; | |
277 | } | |
278 | retval = 0; | |
1da177e4 | 279 | out: |
7ee78232 | 280 | up_write(&mm->mmap_sem); |
fd3e42fc | 281 | flush_tlb_mm(oldmm); |
1da177e4 LT |
282 | up_write(&oldmm->mmap_sem); |
283 | return retval; | |
284 | fail_nomem_policy: | |
285 | kmem_cache_free(vm_area_cachep, tmp); | |
286 | fail_nomem: | |
287 | retval = -ENOMEM; | |
288 | vm_unacct_memory(charge); | |
289 | goto out; | |
290 | } | |
291 | ||
292 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
293 | { | |
294 | mm->pgd = pgd_alloc(mm); | |
295 | if (unlikely(!mm->pgd)) | |
296 | return -ENOMEM; | |
297 | return 0; | |
298 | } | |
299 | ||
300 | static inline void mm_free_pgd(struct mm_struct * mm) | |
301 | { | |
302 | pgd_free(mm->pgd); | |
303 | } | |
304 | #else | |
305 | #define dup_mmap(mm, oldmm) (0) | |
306 | #define mm_alloc_pgd(mm) (0) | |
307 | #define mm_free_pgd(mm) | |
308 | #endif /* CONFIG_MMU */ | |
309 | ||
310 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); | |
311 | ||
312 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL)) | |
313 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
314 | ||
315 | #include <linux/init_task.h> | |
316 | ||
317 | static struct mm_struct * mm_init(struct mm_struct * mm) | |
318 | { | |
319 | atomic_set(&mm->mm_users, 1); | |
320 | atomic_set(&mm->mm_count, 1); | |
321 | init_rwsem(&mm->mmap_sem); | |
322 | INIT_LIST_HEAD(&mm->mmlist); | |
323 | mm->core_waiters = 0; | |
324 | mm->nr_ptes = 0; | |
4294621f | 325 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 326 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
327 | spin_lock_init(&mm->page_table_lock); |
328 | rwlock_init(&mm->ioctx_list_lock); | |
329 | mm->ioctx_list = NULL; | |
1da177e4 | 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 | ||
a0a7ec30 JD |
452 | /* |
453 | * Allocate a new mm structure and copy contents from the | |
454 | * mm structure of the passed in task structure. | |
455 | */ | |
456 | static struct mm_struct *dup_mm(struct task_struct *tsk) | |
457 | { | |
458 | struct mm_struct *mm, *oldmm = current->mm; | |
459 | int err; | |
460 | ||
461 | if (!oldmm) | |
462 | return NULL; | |
463 | ||
464 | mm = allocate_mm(); | |
465 | if (!mm) | |
466 | goto fail_nomem; | |
467 | ||
468 | memcpy(mm, oldmm, sizeof(*mm)); | |
469 | ||
470 | if (!mm_init(mm)) | |
471 | goto fail_nomem; | |
472 | ||
473 | if (init_new_context(tsk, mm)) | |
474 | goto fail_nocontext; | |
475 | ||
476 | err = dup_mmap(mm, oldmm); | |
477 | if (err) | |
478 | goto free_pt; | |
479 | ||
480 | mm->hiwater_rss = get_mm_rss(mm); | |
481 | mm->hiwater_vm = mm->total_vm; | |
482 | ||
483 | return mm; | |
484 | ||
485 | free_pt: | |
486 | mmput(mm); | |
487 | ||
488 | fail_nomem: | |
489 | return NULL; | |
490 | ||
491 | fail_nocontext: | |
492 | /* | |
493 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
494 | * because it calls destroy_context() | |
495 | */ | |
496 | mm_free_pgd(mm); | |
497 | free_mm(mm); | |
498 | return NULL; | |
499 | } | |
500 | ||
1da177e4 LT |
501 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
502 | { | |
503 | struct mm_struct * mm, *oldmm; | |
504 | int retval; | |
505 | ||
506 | tsk->min_flt = tsk->maj_flt = 0; | |
507 | tsk->nvcsw = tsk->nivcsw = 0; | |
508 | ||
509 | tsk->mm = NULL; | |
510 | tsk->active_mm = NULL; | |
511 | ||
512 | /* | |
513 | * Are we cloning a kernel thread? | |
514 | * | |
515 | * We need to steal a active VM for that.. | |
516 | */ | |
517 | oldmm = current->mm; | |
518 | if (!oldmm) | |
519 | return 0; | |
520 | ||
521 | if (clone_flags & CLONE_VM) { | |
522 | atomic_inc(&oldmm->mm_users); | |
523 | mm = oldmm; | |
1da177e4 LT |
524 | goto good_mm; |
525 | } | |
526 | ||
527 | retval = -ENOMEM; | |
a0a7ec30 | 528 | mm = dup_mm(tsk); |
1da177e4 LT |
529 | if (!mm) |
530 | goto fail_nomem; | |
531 | ||
1da177e4 LT |
532 | good_mm: |
533 | tsk->mm = mm; | |
534 | tsk->active_mm = mm; | |
535 | return 0; | |
536 | ||
1da177e4 LT |
537 | fail_nomem: |
538 | return retval; | |
1da177e4 LT |
539 | } |
540 | ||
541 | static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old) | |
542 | { | |
543 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
544 | /* We don't need to lock fs - think why ;-) */ | |
545 | if (fs) { | |
546 | atomic_set(&fs->count, 1); | |
547 | rwlock_init(&fs->lock); | |
548 | fs->umask = old->umask; | |
549 | read_lock(&old->lock); | |
550 | fs->rootmnt = mntget(old->rootmnt); | |
551 | fs->root = dget(old->root); | |
552 | fs->pwdmnt = mntget(old->pwdmnt); | |
553 | fs->pwd = dget(old->pwd); | |
554 | if (old->altroot) { | |
555 | fs->altrootmnt = mntget(old->altrootmnt); | |
556 | fs->altroot = dget(old->altroot); | |
557 | } else { | |
558 | fs->altrootmnt = NULL; | |
559 | fs->altroot = NULL; | |
560 | } | |
561 | read_unlock(&old->lock); | |
562 | } | |
563 | return fs; | |
564 | } | |
565 | ||
566 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
567 | { | |
568 | return __copy_fs_struct(old); | |
569 | } | |
570 | ||
571 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
572 | ||
573 | static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk) | |
574 | { | |
575 | if (clone_flags & CLONE_FS) { | |
576 | atomic_inc(¤t->fs->count); | |
577 | return 0; | |
578 | } | |
579 | tsk->fs = __copy_fs_struct(current->fs); | |
580 | if (!tsk->fs) | |
581 | return -ENOMEM; | |
582 | return 0; | |
583 | } | |
584 | ||
ab2af1f5 | 585 | static int count_open_files(struct fdtable *fdt) |
1da177e4 | 586 | { |
ab2af1f5 | 587 | int size = fdt->max_fdset; |
1da177e4 LT |
588 | int i; |
589 | ||
590 | /* Find the last open fd */ | |
591 | for (i = size/(8*sizeof(long)); i > 0; ) { | |
badf1662 | 592 | if (fdt->open_fds->fds_bits[--i]) |
1da177e4 LT |
593 | break; |
594 | } | |
595 | i = (i+1) * 8 * sizeof(long); | |
596 | return i; | |
597 | } | |
598 | ||
badf1662 DS |
599 | static struct files_struct *alloc_files(void) |
600 | { | |
601 | struct files_struct *newf; | |
602 | struct fdtable *fdt; | |
603 | ||
604 | newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL); | |
605 | if (!newf) | |
606 | goto out; | |
607 | ||
608 | atomic_set(&newf->count, 1); | |
609 | ||
610 | spin_lock_init(&newf->file_lock); | |
0c9e63fd | 611 | newf->next_fd = 0; |
ab2af1f5 | 612 | fdt = &newf->fdtab; |
badf1662 | 613 | fdt->max_fds = NR_OPEN_DEFAULT; |
0c9e63fd ED |
614 | fdt->max_fdset = EMBEDDED_FD_SET_SIZE; |
615 | fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init; | |
616 | fdt->open_fds = (fd_set *)&newf->open_fds_init; | |
badf1662 | 617 | fdt->fd = &newf->fd_array[0]; |
ab2af1f5 DS |
618 | INIT_RCU_HEAD(&fdt->rcu); |
619 | fdt->free_files = NULL; | |
620 | fdt->next = NULL; | |
621 | rcu_assign_pointer(newf->fdt, fdt); | |
badf1662 DS |
622 | out: |
623 | return newf; | |
624 | } | |
625 | ||
a016f338 JD |
626 | /* |
627 | * Allocate a new files structure and copy contents from the | |
628 | * passed in files structure. | |
629 | */ | |
630 | static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) | |
1da177e4 | 631 | { |
a016f338 | 632 | struct files_struct *newf; |
1da177e4 | 633 | struct file **old_fds, **new_fds; |
a016f338 | 634 | int open_files, size, i, expand; |
badf1662 | 635 | struct fdtable *old_fdt, *new_fdt; |
1da177e4 | 636 | |
badf1662 DS |
637 | newf = alloc_files(); |
638 | if (!newf) | |
1da177e4 LT |
639 | goto out; |
640 | ||
1da177e4 | 641 | spin_lock(&oldf->file_lock); |
badf1662 DS |
642 | old_fdt = files_fdtable(oldf); |
643 | new_fdt = files_fdtable(newf); | |
644 | size = old_fdt->max_fdset; | |
ab2af1f5 | 645 | open_files = count_open_files(old_fdt); |
1da177e4 LT |
646 | expand = 0; |
647 | ||
648 | /* | |
649 | * Check whether we need to allocate a larger fd array or fd set. | |
650 | * Note: we're not a clone task, so the open count won't change. | |
651 | */ | |
badf1662 DS |
652 | if (open_files > new_fdt->max_fdset) { |
653 | new_fdt->max_fdset = 0; | |
1da177e4 LT |
654 | expand = 1; |
655 | } | |
badf1662 DS |
656 | if (open_files > new_fdt->max_fds) { |
657 | new_fdt->max_fds = 0; | |
1da177e4 LT |
658 | expand = 1; |
659 | } | |
660 | ||
661 | /* if the old fdset gets grown now, we'll only copy up to "size" fds */ | |
662 | if (expand) { | |
663 | spin_unlock(&oldf->file_lock); | |
664 | spin_lock(&newf->file_lock); | |
a016f338 | 665 | *errorp = expand_files(newf, open_files-1); |
1da177e4 | 666 | spin_unlock(&newf->file_lock); |
a016f338 | 667 | if (*errorp < 0) |
1da177e4 | 668 | goto out_release; |
ab2af1f5 DS |
669 | new_fdt = files_fdtable(newf); |
670 | /* | |
671 | * Reacquire the oldf lock and a pointer to its fd table | |
672 | * who knows it may have a new bigger fd table. We need | |
673 | * the latest pointer. | |
674 | */ | |
1da177e4 | 675 | spin_lock(&oldf->file_lock); |
ab2af1f5 | 676 | old_fdt = files_fdtable(oldf); |
1da177e4 LT |
677 | } |
678 | ||
badf1662 DS |
679 | old_fds = old_fdt->fd; |
680 | new_fds = new_fdt->fd; | |
1da177e4 | 681 | |
badf1662 DS |
682 | memcpy(new_fdt->open_fds->fds_bits, old_fdt->open_fds->fds_bits, open_files/8); |
683 | memcpy(new_fdt->close_on_exec->fds_bits, old_fdt->close_on_exec->fds_bits, open_files/8); | |
1da177e4 LT |
684 | |
685 | for (i = open_files; i != 0; i--) { | |
686 | struct file *f = *old_fds++; | |
687 | if (f) { | |
688 | get_file(f); | |
689 | } else { | |
690 | /* | |
691 | * The fd may be claimed in the fd bitmap but not yet | |
692 | * instantiated in the files array if a sibling thread | |
693 | * is partway through open(). So make sure that this | |
694 | * fd is available to the new process. | |
695 | */ | |
badf1662 | 696 | FD_CLR(open_files - i, new_fdt->open_fds); |
1da177e4 | 697 | } |
ab2af1f5 | 698 | rcu_assign_pointer(*new_fds++, f); |
1da177e4 LT |
699 | } |
700 | spin_unlock(&oldf->file_lock); | |
701 | ||
702 | /* compute the remainder to be cleared */ | |
badf1662 | 703 | size = (new_fdt->max_fds - open_files) * sizeof(struct file *); |
1da177e4 LT |
704 | |
705 | /* This is long word aligned thus could use a optimized version */ | |
706 | memset(new_fds, 0, size); | |
707 | ||
badf1662 DS |
708 | if (new_fdt->max_fdset > open_files) { |
709 | int left = (new_fdt->max_fdset-open_files)/8; | |
1da177e4 LT |
710 | int start = open_files / (8 * sizeof(unsigned long)); |
711 | ||
badf1662 DS |
712 | memset(&new_fdt->open_fds->fds_bits[start], 0, left); |
713 | memset(&new_fdt->close_on_exec->fds_bits[start], 0, left); | |
1da177e4 LT |
714 | } |
715 | ||
1da177e4 | 716 | out: |
a016f338 | 717 | return newf; |
1da177e4 LT |
718 | |
719 | out_release: | |
badf1662 DS |
720 | free_fdset (new_fdt->close_on_exec, new_fdt->max_fdset); |
721 | free_fdset (new_fdt->open_fds, new_fdt->max_fdset); | |
722 | free_fd_array(new_fdt->fd, new_fdt->max_fds); | |
1da177e4 LT |
723 | kmem_cache_free(files_cachep, newf); |
724 | goto out; | |
725 | } | |
726 | ||
a016f338 JD |
727 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
728 | { | |
729 | struct files_struct *oldf, *newf; | |
730 | int error = 0; | |
731 | ||
732 | /* | |
733 | * A background process may not have any files ... | |
734 | */ | |
735 | oldf = current->files; | |
736 | if (!oldf) | |
737 | goto out; | |
738 | ||
739 | if (clone_flags & CLONE_FILES) { | |
740 | atomic_inc(&oldf->count); | |
741 | goto out; | |
742 | } | |
743 | ||
744 | /* | |
745 | * Note: we may be using current for both targets (See exec.c) | |
746 | * This works because we cache current->files (old) as oldf. Don't | |
747 | * break this. | |
748 | */ | |
749 | tsk->files = NULL; | |
750 | error = -ENOMEM; | |
751 | newf = dup_fd(oldf, &error); | |
752 | if (!newf) | |
753 | goto out; | |
754 | ||
755 | tsk->files = newf; | |
756 | error = 0; | |
757 | out: | |
758 | return error; | |
759 | } | |
760 | ||
1da177e4 LT |
761 | /* |
762 | * Helper to unshare the files of the current task. | |
763 | * We don't want to expose copy_files internals to | |
764 | * the exec layer of the kernel. | |
765 | */ | |
766 | ||
767 | int unshare_files(void) | |
768 | { | |
769 | struct files_struct *files = current->files; | |
770 | int rc; | |
771 | ||
910dea7f | 772 | BUG_ON(!files); |
1da177e4 LT |
773 | |
774 | /* This can race but the race causes us to copy when we don't | |
775 | need to and drop the copy */ | |
776 | if(atomic_read(&files->count) == 1) | |
777 | { | |
778 | atomic_inc(&files->count); | |
779 | return 0; | |
780 | } | |
781 | rc = copy_files(0, current); | |
782 | if(rc) | |
783 | current->files = files; | |
784 | return rc; | |
785 | } | |
786 | ||
787 | EXPORT_SYMBOL(unshare_files); | |
788 | ||
789 | static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk) | |
790 | { | |
791 | struct sighand_struct *sig; | |
792 | ||
793 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
794 | atomic_inc(¤t->sighand->count); | |
795 | return 0; | |
796 | } | |
797 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 798 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
799 | if (!sig) |
800 | return -ENOMEM; | |
1da177e4 LT |
801 | atomic_set(&sig->count, 1); |
802 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
803 | return 0; | |
804 | } | |
805 | ||
c81addc9 ON |
806 | void cleanup_sighand(struct task_struct *tsk) |
807 | { | |
808 | struct sighand_struct * sighand = tsk->sighand; | |
809 | ||
810 | /* Ok, we're done with the signal handlers */ | |
811 | tsk->sighand = NULL; | |
812 | if (atomic_dec_and_test(&sighand->count)) | |
813 | kmem_cache_free(sighand_cachep, sighand); | |
814 | } | |
815 | ||
1da177e4 LT |
816 | static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk) |
817 | { | |
818 | struct signal_struct *sig; | |
819 | int ret; | |
820 | ||
821 | if (clone_flags & CLONE_THREAD) { | |
822 | atomic_inc(¤t->signal->count); | |
823 | atomic_inc(¤t->signal->live); | |
824 | return 0; | |
825 | } | |
826 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
827 | tsk->signal = sig; | |
828 | if (!sig) | |
829 | return -ENOMEM; | |
830 | ||
831 | ret = copy_thread_group_keys(tsk); | |
832 | if (ret < 0) { | |
833 | kmem_cache_free(signal_cachep, sig); | |
834 | return ret; | |
835 | } | |
836 | ||
837 | atomic_set(&sig->count, 1); | |
838 | atomic_set(&sig->live, 1); | |
839 | init_waitqueue_head(&sig->wait_chldexit); | |
840 | sig->flags = 0; | |
841 | sig->group_exit_code = 0; | |
842 | sig->group_exit_task = NULL; | |
843 | sig->group_stop_count = 0; | |
844 | sig->curr_target = NULL; | |
845 | init_sigpending(&sig->shared_pending); | |
846 | INIT_LIST_HEAD(&sig->posix_timers); | |
847 | ||
7978672c | 848 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL); |
2ff678b8 | 849 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 850 | sig->real_timer.function = it_real_fn; |
05cfb614 | 851 | sig->tsk = tsk; |
1da177e4 LT |
852 | |
853 | sig->it_virt_expires = cputime_zero; | |
854 | sig->it_virt_incr = cputime_zero; | |
855 | sig->it_prof_expires = cputime_zero; | |
856 | sig->it_prof_incr = cputime_zero; | |
857 | ||
1da177e4 LT |
858 | sig->leader = 0; /* session leadership doesn't inherit */ |
859 | sig->tty_old_pgrp = 0; | |
860 | ||
861 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
862 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; | |
863 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
864 | sig->sched_time = 0; | |
865 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
866 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
867 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
868 | ||
869 | task_lock(current->group_leader); | |
870 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
871 | task_unlock(current->group_leader); | |
872 | ||
873 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
874 | /* | |
875 | * New sole thread in the process gets an expiry time | |
876 | * of the whole CPU time limit. | |
877 | */ | |
878 | tsk->it_prof_expires = | |
879 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
880 | } | |
881 | ||
882 | return 0; | |
883 | } | |
884 | ||
6b3934ef ON |
885 | void __cleanup_signal(struct signal_struct *sig) |
886 | { | |
887 | exit_thread_group_keys(sig); | |
888 | kmem_cache_free(signal_cachep, sig); | |
889 | } | |
890 | ||
891 | static inline void cleanup_signal(struct task_struct *tsk) | |
892 | { | |
893 | struct signal_struct *sig = tsk->signal; | |
894 | ||
895 | atomic_dec(&sig->live); | |
896 | ||
897 | if (atomic_dec_and_test(&sig->count)) | |
898 | __cleanup_signal(sig); | |
899 | } | |
900 | ||
1da177e4 LT |
901 | static inline void copy_flags(unsigned long clone_flags, struct task_struct *p) |
902 | { | |
903 | unsigned long new_flags = p->flags; | |
904 | ||
d1209d04 | 905 | new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE); |
1da177e4 LT |
906 | new_flags |= PF_FORKNOEXEC; |
907 | if (!(clone_flags & CLONE_PTRACE)) | |
908 | p->ptrace = 0; | |
909 | p->flags = new_flags; | |
910 | } | |
911 | ||
912 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
913 | { | |
914 | current->clear_child_tid = tidptr; | |
915 | ||
916 | return current->pid; | |
917 | } | |
918 | ||
919 | /* | |
920 | * This creates a new process as a copy of the old one, | |
921 | * but does not actually start it yet. | |
922 | * | |
923 | * It copies the registers, and all the appropriate | |
924 | * parts of the process environment (as per the clone | |
925 | * flags). The actual kick-off is left to the caller. | |
926 | */ | |
927 | static task_t *copy_process(unsigned long clone_flags, | |
928 | unsigned long stack_start, | |
929 | struct pt_regs *regs, | |
930 | unsigned long stack_size, | |
931 | int __user *parent_tidptr, | |
932 | int __user *child_tidptr, | |
933 | int pid) | |
934 | { | |
935 | int retval; | |
936 | struct task_struct *p = NULL; | |
937 | ||
938 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
939 | return ERR_PTR(-EINVAL); | |
940 | ||
941 | /* | |
942 | * Thread groups must share signals as well, and detached threads | |
943 | * can only be started up within the thread group. | |
944 | */ | |
945 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
946 | return ERR_PTR(-EINVAL); | |
947 | ||
948 | /* | |
949 | * Shared signal handlers imply shared VM. By way of the above, | |
950 | * thread groups also imply shared VM. Blocking this case allows | |
951 | * for various simplifications in other code. | |
952 | */ | |
953 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
954 | return ERR_PTR(-EINVAL); | |
955 | ||
956 | retval = security_task_create(clone_flags); | |
957 | if (retval) | |
958 | goto fork_out; | |
959 | ||
960 | retval = -ENOMEM; | |
961 | p = dup_task_struct(current); | |
962 | if (!p) | |
963 | goto fork_out; | |
964 | ||
965 | retval = -EAGAIN; | |
966 | if (atomic_read(&p->user->processes) >= | |
967 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
968 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
969 | p->user != &root_user) | |
970 | goto bad_fork_free; | |
971 | } | |
972 | ||
973 | atomic_inc(&p->user->__count); | |
974 | atomic_inc(&p->user->processes); | |
975 | get_group_info(p->group_info); | |
976 | ||
977 | /* | |
978 | * If multiple threads are within copy_process(), then this check | |
979 | * triggers too late. This doesn't hurt, the check is only there | |
980 | * to stop root fork bombs. | |
981 | */ | |
982 | if (nr_threads >= max_threads) | |
983 | goto bad_fork_cleanup_count; | |
984 | ||
a1261f54 | 985 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
986 | goto bad_fork_cleanup_count; |
987 | ||
988 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
989 | goto bad_fork_cleanup_put_domain; | |
990 | ||
991 | p->did_exec = 0; | |
992 | copy_flags(clone_flags, p); | |
993 | p->pid = pid; | |
994 | retval = -EFAULT; | |
995 | if (clone_flags & CLONE_PARENT_SETTID) | |
996 | if (put_user(p->pid, parent_tidptr)) | |
997 | goto bad_fork_cleanup; | |
998 | ||
999 | p->proc_dentry = NULL; | |
1000 | ||
1001 | INIT_LIST_HEAD(&p->children); | |
1002 | INIT_LIST_HEAD(&p->sibling); | |
1003 | p->vfork_done = NULL; | |
1004 | spin_lock_init(&p->alloc_lock); | |
1005 | spin_lock_init(&p->proc_lock); | |
1006 | ||
1007 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
1008 | init_sigpending(&p->pending); | |
1009 | ||
1010 | p->utime = cputime_zero; | |
1011 | p->stime = cputime_zero; | |
1012 | p->sched_time = 0; | |
1013 | p->rchar = 0; /* I/O counter: bytes read */ | |
1014 | p->wchar = 0; /* I/O counter: bytes written */ | |
1015 | p->syscr = 0; /* I/O counter: read syscalls */ | |
1016 | p->syscw = 0; /* I/O counter: write syscalls */ | |
1017 | acct_clear_integrals(p); | |
1018 | ||
1019 | p->it_virt_expires = cputime_zero; | |
1020 | p->it_prof_expires = cputime_zero; | |
1021 | p->it_sched_expires = 0; | |
1022 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1023 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1024 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1025 | ||
1026 | p->lock_depth = -1; /* -1 = no lock */ | |
1027 | do_posix_clock_monotonic_gettime(&p->start_time); | |
1028 | p->security = NULL; | |
1029 | p->io_context = NULL; | |
1030 | p->io_wait = NULL; | |
1031 | p->audit_context = NULL; | |
b4b26418 | 1032 | cpuset_fork(p); |
1da177e4 LT |
1033 | #ifdef CONFIG_NUMA |
1034 | p->mempolicy = mpol_copy(p->mempolicy); | |
1035 | if (IS_ERR(p->mempolicy)) { | |
1036 | retval = PTR_ERR(p->mempolicy); | |
1037 | p->mempolicy = NULL; | |
b4b26418 | 1038 | goto bad_fork_cleanup_cpuset; |
1da177e4 | 1039 | } |
c61afb18 | 1040 | mpol_fix_fork_child_flag(p); |
1da177e4 LT |
1041 | #endif |
1042 | ||
408894ee IM |
1043 | #ifdef CONFIG_DEBUG_MUTEXES |
1044 | p->blocked_on = NULL; /* not blocked yet */ | |
1045 | #endif | |
1046 | ||
1da177e4 LT |
1047 | p->tgid = p->pid; |
1048 | if (clone_flags & CLONE_THREAD) | |
1049 | p->tgid = current->tgid; | |
1050 | ||
1051 | if ((retval = security_task_alloc(p))) | |
1052 | goto bad_fork_cleanup_policy; | |
1053 | if ((retval = audit_alloc(p))) | |
1054 | goto bad_fork_cleanup_security; | |
1055 | /* copy all the process information */ | |
1056 | if ((retval = copy_semundo(clone_flags, p))) | |
1057 | goto bad_fork_cleanup_audit; | |
1058 | if ((retval = copy_files(clone_flags, p))) | |
1059 | goto bad_fork_cleanup_semundo; | |
1060 | if ((retval = copy_fs(clone_flags, p))) | |
1061 | goto bad_fork_cleanup_files; | |
1062 | if ((retval = copy_sighand(clone_flags, p))) | |
1063 | goto bad_fork_cleanup_fs; | |
1064 | if ((retval = copy_signal(clone_flags, p))) | |
1065 | goto bad_fork_cleanup_sighand; | |
1066 | if ((retval = copy_mm(clone_flags, p))) | |
1067 | goto bad_fork_cleanup_signal; | |
1068 | if ((retval = copy_keys(clone_flags, p))) | |
1069 | goto bad_fork_cleanup_mm; | |
1070 | if ((retval = copy_namespace(clone_flags, p))) | |
1071 | goto bad_fork_cleanup_keys; | |
1072 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); | |
1073 | if (retval) | |
1074 | goto bad_fork_cleanup_namespace; | |
1075 | ||
1076 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; | |
1077 | /* | |
1078 | * Clear TID on mm_release()? | |
1079 | */ | |
1080 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
8f17d3a5 IM |
1081 | p->robust_list = NULL; |
1082 | #ifdef CONFIG_COMPAT | |
1083 | p->compat_robust_list = NULL; | |
1084 | #endif | |
f9a3879a GM |
1085 | /* |
1086 | * sigaltstack should be cleared when sharing the same VM | |
1087 | */ | |
1088 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1089 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1090 | ||
1da177e4 LT |
1091 | /* |
1092 | * Syscall tracing should be turned off in the child regardless | |
1093 | * of CLONE_PTRACE. | |
1094 | */ | |
1095 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1096 | #ifdef TIF_SYSCALL_EMU |
1097 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1098 | #endif | |
1da177e4 LT |
1099 | |
1100 | /* Our parent execution domain becomes current domain | |
1101 | These must match for thread signalling to apply */ | |
1102 | ||
1103 | p->parent_exec_id = p->self_exec_id; | |
1104 | ||
1105 | /* ok, now we should be set up.. */ | |
1106 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1107 | p->pdeath_signal = 0; | |
1108 | p->exit_state = 0; | |
1109 | ||
1da177e4 LT |
1110 | /* |
1111 | * Ok, make it visible to the rest of the system. | |
1112 | * We dont wake it up yet. | |
1113 | */ | |
1114 | p->group_leader = p; | |
47e65328 | 1115 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 LT |
1116 | INIT_LIST_HEAD(&p->ptrace_children); |
1117 | INIT_LIST_HEAD(&p->ptrace_list); | |
1118 | ||
476d139c NP |
1119 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1120 | sched_fork(p, clone_flags); | |
1121 | ||
1da177e4 LT |
1122 | /* Need tasklist lock for parent etc handling! */ |
1123 | write_lock_irq(&tasklist_lock); | |
1124 | ||
1125 | /* | |
476d139c NP |
1126 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1127 | * not be changed, nor will its assigned CPU. | |
1128 | * | |
1129 | * The cpus_allowed mask of the parent may have changed after it was | |
1130 | * copied first time - so re-copy it here, then check the child's CPU | |
1131 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1132 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1133 | */ |
1134 | p->cpus_allowed = current->cpus_allowed; | |
26ff6ad9 SV |
1135 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1136 | !cpu_online(task_cpu(p)))) | |
476d139c | 1137 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1138 | |
1da177e4 LT |
1139 | /* CLONE_PARENT re-uses the old parent */ |
1140 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1141 | p->real_parent = current->real_parent; | |
1142 | else | |
1143 | p->real_parent = current; | |
1144 | p->parent = p->real_parent; | |
1145 | ||
3f17da69 | 1146 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1147 | |
1148 | /* | |
1149 | * Process group and session signals need to be delivered to just the | |
1150 | * parent before the fork or both the parent and the child after the | |
1151 | * fork. Restart if a signal comes in before we add the new process to | |
1152 | * it's process group. | |
1153 | * A fatal signal pending means that current will exit, so the new | |
1154 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1155 | */ | |
1156 | recalc_sigpending(); | |
1157 | if (signal_pending(current)) { | |
1158 | spin_unlock(¤t->sighand->siglock); | |
1159 | write_unlock_irq(&tasklist_lock); | |
1160 | retval = -ERESTARTNOINTR; | |
1161 | goto bad_fork_cleanup_namespace; | |
1162 | } | |
1163 | ||
1da177e4 | 1164 | if (clone_flags & CLONE_THREAD) { |
1da177e4 LT |
1165 | /* |
1166 | * Important: if an exit-all has been started then | |
1167 | * do not create this new thread - the whole thread | |
1168 | * group is supposed to exit anyway. | |
1169 | */ | |
1170 | if (current->signal->flags & SIGNAL_GROUP_EXIT) { | |
1171 | spin_unlock(¤t->sighand->siglock); | |
1172 | write_unlock_irq(&tasklist_lock); | |
1173 | retval = -EAGAIN; | |
1174 | goto bad_fork_cleanup_namespace; | |
1175 | } | |
47e65328 | 1176 | |
1da177e4 | 1177 | p->group_leader = current->group_leader; |
47e65328 | 1178 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1179 | |
1da177e4 LT |
1180 | if (!cputime_eq(current->signal->it_virt_expires, |
1181 | cputime_zero) || | |
1182 | !cputime_eq(current->signal->it_prof_expires, | |
1183 | cputime_zero) || | |
1184 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1185 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1186 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1187 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1188 | /* | |
1189 | * Have child wake up on its first tick to check | |
1190 | * for process CPU timers. | |
1191 | */ | |
1192 | p->it_prof_expires = jiffies_to_cputime(1); | |
1193 | } | |
1da177e4 LT |
1194 | } |
1195 | ||
22e2c507 JA |
1196 | /* |
1197 | * inherit ioprio | |
1198 | */ | |
1199 | p->ioprio = current->ioprio; | |
1200 | ||
73b9ebfe ON |
1201 | if (likely(p->pid)) { |
1202 | add_parent(p); | |
1203 | if (unlikely(p->ptrace & PT_PTRACED)) | |
1204 | __ptrace_link(p, current->parent); | |
1205 | ||
1206 | if (thread_group_leader(p)) { | |
1207 | p->signal->tty = current->signal->tty; | |
1208 | p->signal->pgrp = process_group(current); | |
1209 | p->signal->session = current->signal->session; | |
1210 | attach_pid(p, PIDTYPE_PGID, process_group(p)); | |
1211 | attach_pid(p, PIDTYPE_SID, p->signal->session); | |
1212 | ||
1213 | list_add_tail(&p->tasks, &init_task.tasks); | |
1da177e4 | 1214 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1215 | } |
73b9ebfe ON |
1216 | attach_pid(p, PIDTYPE_PID, p->pid); |
1217 | nr_threads++; | |
1da177e4 LT |
1218 | } |
1219 | ||
1da177e4 | 1220 | total_forks++; |
3f17da69 | 1221 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1222 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1223 | proc_fork_connector(p); |
1da177e4 LT |
1224 | return p; |
1225 | ||
1226 | bad_fork_cleanup_namespace: | |
1227 | exit_namespace(p); | |
1228 | bad_fork_cleanup_keys: | |
1229 | exit_keys(p); | |
1230 | bad_fork_cleanup_mm: | |
1231 | if (p->mm) | |
1232 | mmput(p->mm); | |
1233 | bad_fork_cleanup_signal: | |
6b3934ef | 1234 | cleanup_signal(p); |
1da177e4 | 1235 | bad_fork_cleanup_sighand: |
c81addc9 | 1236 | cleanup_sighand(p); |
1da177e4 LT |
1237 | bad_fork_cleanup_fs: |
1238 | exit_fs(p); /* blocking */ | |
1239 | bad_fork_cleanup_files: | |
1240 | exit_files(p); /* blocking */ | |
1241 | bad_fork_cleanup_semundo: | |
1242 | exit_sem(p); | |
1243 | bad_fork_cleanup_audit: | |
1244 | audit_free(p); | |
1245 | bad_fork_cleanup_security: | |
1246 | security_task_free(p); | |
1247 | bad_fork_cleanup_policy: | |
1248 | #ifdef CONFIG_NUMA | |
1249 | mpol_free(p->mempolicy); | |
b4b26418 | 1250 | bad_fork_cleanup_cpuset: |
1da177e4 | 1251 | #endif |
b4b26418 | 1252 | cpuset_exit(p); |
1da177e4 LT |
1253 | bad_fork_cleanup: |
1254 | if (p->binfmt) | |
1255 | module_put(p->binfmt->module); | |
1256 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1257 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1258 | bad_fork_cleanup_count: |
1259 | put_group_info(p->group_info); | |
1260 | atomic_dec(&p->user->processes); | |
1261 | free_uid(p->user); | |
1262 | bad_fork_free: | |
1263 | free_task(p); | |
fe7d37d1 ON |
1264 | fork_out: |
1265 | return ERR_PTR(retval); | |
1da177e4 LT |
1266 | } |
1267 | ||
1268 | struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs) | |
1269 | { | |
1270 | memset(regs, 0, sizeof(struct pt_regs)); | |
1271 | return regs; | |
1272 | } | |
1273 | ||
1274 | task_t * __devinit fork_idle(int cpu) | |
1275 | { | |
1276 | task_t *task; | |
1277 | struct pt_regs regs; | |
1278 | ||
1279 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0); | |
1280 | if (!task) | |
1281 | return ERR_PTR(-ENOMEM); | |
1282 | init_idle(task, cpu); | |
73b9ebfe | 1283 | |
1da177e4 LT |
1284 | return task; |
1285 | } | |
1286 | ||
1287 | static inline int fork_traceflag (unsigned clone_flags) | |
1288 | { | |
1289 | if (clone_flags & CLONE_UNTRACED) | |
1290 | return 0; | |
1291 | else if (clone_flags & CLONE_VFORK) { | |
1292 | if (current->ptrace & PT_TRACE_VFORK) | |
1293 | return PTRACE_EVENT_VFORK; | |
1294 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1295 | if (current->ptrace & PT_TRACE_CLONE) | |
1296 | return PTRACE_EVENT_CLONE; | |
1297 | } else if (current->ptrace & PT_TRACE_FORK) | |
1298 | return PTRACE_EVENT_FORK; | |
1299 | ||
1300 | return 0; | |
1301 | } | |
1302 | ||
1303 | /* | |
1304 | * Ok, this is the main fork-routine. | |
1305 | * | |
1306 | * It copies the process, and if successful kick-starts | |
1307 | * it and waits for it to finish using the VM if required. | |
1308 | */ | |
1309 | long do_fork(unsigned long clone_flags, | |
1310 | unsigned long stack_start, | |
1311 | struct pt_regs *regs, | |
1312 | unsigned long stack_size, | |
1313 | int __user *parent_tidptr, | |
1314 | int __user *child_tidptr) | |
1315 | { | |
1316 | struct task_struct *p; | |
1317 | int trace = 0; | |
1318 | long pid = alloc_pidmap(); | |
1319 | ||
1320 | if (pid < 0) | |
1321 | return -EAGAIN; | |
1322 | if (unlikely(current->ptrace)) { | |
1323 | trace = fork_traceflag (clone_flags); | |
1324 | if (trace) | |
1325 | clone_flags |= CLONE_PTRACE; | |
1326 | } | |
1327 | ||
1328 | p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid); | |
1329 | /* | |
1330 | * Do this prior waking up the new thread - the thread pointer | |
1331 | * might get invalid after that point, if the thread exits quickly. | |
1332 | */ | |
1333 | if (!IS_ERR(p)) { | |
1334 | struct completion vfork; | |
1335 | ||
1336 | if (clone_flags & CLONE_VFORK) { | |
1337 | p->vfork_done = &vfork; | |
1338 | init_completion(&vfork); | |
1339 | } | |
1340 | ||
1341 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1342 | /* | |
1343 | * We'll start up with an immediate SIGSTOP. | |
1344 | */ | |
1345 | sigaddset(&p->pending.signal, SIGSTOP); | |
1346 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1347 | } | |
1348 | ||
1349 | if (!(clone_flags & CLONE_STOPPED)) | |
1350 | wake_up_new_task(p, clone_flags); | |
1351 | else | |
1352 | p->state = TASK_STOPPED; | |
1353 | ||
1354 | if (unlikely (trace)) { | |
1355 | current->ptrace_message = pid; | |
1356 | ptrace_notify ((trace << 8) | SIGTRAP); | |
1357 | } | |
1358 | ||
1359 | if (clone_flags & CLONE_VFORK) { | |
1360 | wait_for_completion(&vfork); | |
1361 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) | |
1362 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); | |
1363 | } | |
1364 | } else { | |
1365 | free_pidmap(pid); | |
1366 | pid = PTR_ERR(p); | |
1367 | } | |
1368 | return pid; | |
1369 | } | |
1370 | ||
5fd63b30 RT |
1371 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1372 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1373 | #endif | |
1374 | ||
aa1757f9 ON |
1375 | static void sighand_ctor(void *data, kmem_cache_t *cachep, unsigned long flags) |
1376 | { | |
1377 | struct sighand_struct *sighand = data; | |
1378 | ||
1379 | if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == | |
1380 | SLAB_CTOR_CONSTRUCTOR) | |
1381 | spin_lock_init(&sighand->siglock); | |
1382 | } | |
1383 | ||
1da177e4 LT |
1384 | void __init proc_caches_init(void) |
1385 | { | |
1386 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1387 | sizeof(struct sighand_struct), 0, | |
aa1757f9 ON |
1388 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
1389 | sighand_ctor, NULL); | |
1da177e4 LT |
1390 | signal_cachep = kmem_cache_create("signal_cache", |
1391 | sizeof(struct signal_struct), 0, | |
1392 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1393 | files_cachep = kmem_cache_create("files_cache", | |
1394 | sizeof(struct files_struct), 0, | |
1395 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1396 | fs_cachep = kmem_cache_create("fs_cache", | |
1397 | sizeof(struct fs_struct), 0, | |
1398 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1399 | vm_area_cachep = kmem_cache_create("vm_area_struct", | |
1400 | sizeof(struct vm_area_struct), 0, | |
1401 | SLAB_PANIC, NULL, NULL); | |
1402 | mm_cachep = kmem_cache_create("mm_struct", | |
5fd63b30 | 1403 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
1da177e4 LT |
1404 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
1405 | } | |
cf2e340f JD |
1406 | |
1407 | ||
1408 | /* | |
1409 | * Check constraints on flags passed to the unshare system call and | |
1410 | * force unsharing of additional process context as appropriate. | |
1411 | */ | |
1412 | static inline void check_unshare_flags(unsigned long *flags_ptr) | |
1413 | { | |
1414 | /* | |
1415 | * If unsharing a thread from a thread group, must also | |
1416 | * unshare vm. | |
1417 | */ | |
1418 | if (*flags_ptr & CLONE_THREAD) | |
1419 | *flags_ptr |= CLONE_VM; | |
1420 | ||
1421 | /* | |
1422 | * If unsharing vm, must also unshare signal handlers. | |
1423 | */ | |
1424 | if (*flags_ptr & CLONE_VM) | |
1425 | *flags_ptr |= CLONE_SIGHAND; | |
1426 | ||
1427 | /* | |
1428 | * If unsharing signal handlers and the task was created | |
1429 | * using CLONE_THREAD, then must unshare the thread | |
1430 | */ | |
1431 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1432 | (atomic_read(¤t->signal->count) > 1)) | |
1433 | *flags_ptr |= CLONE_THREAD; | |
1434 | ||
1435 | /* | |
1436 | * If unsharing namespace, must also unshare filesystem information. | |
1437 | */ | |
1438 | if (*flags_ptr & CLONE_NEWNS) | |
1439 | *flags_ptr |= CLONE_FS; | |
1440 | } | |
1441 | ||
1442 | /* | |
1443 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1444 | */ | |
1445 | static int unshare_thread(unsigned long unshare_flags) | |
1446 | { | |
1447 | if (unshare_flags & CLONE_THREAD) | |
1448 | return -EINVAL; | |
1449 | ||
1450 | return 0; | |
1451 | } | |
1452 | ||
1453 | /* | |
99d1419d | 1454 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1455 | */ |
1456 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1457 | { | |
1458 | struct fs_struct *fs = current->fs; | |
1459 | ||
1460 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1461 | (fs && atomic_read(&fs->count) > 1)) { |
1462 | *new_fsp = __copy_fs_struct(current->fs); | |
1463 | if (!*new_fsp) | |
1464 | return -ENOMEM; | |
1465 | } | |
cf2e340f JD |
1466 | |
1467 | return 0; | |
1468 | } | |
1469 | ||
1470 | /* | |
741a2951 | 1471 | * Unshare the namespace structure if it is being shared |
cf2e340f | 1472 | */ |
741a2951 | 1473 | static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs) |
cf2e340f JD |
1474 | { |
1475 | struct namespace *ns = current->namespace; | |
1476 | ||
1477 | if ((unshare_flags & CLONE_NEWNS) && | |
741a2951 JD |
1478 | (ns && atomic_read(&ns->count) > 1)) { |
1479 | if (!capable(CAP_SYS_ADMIN)) | |
1480 | return -EPERM; | |
1481 | ||
1482 | *new_nsp = dup_namespace(current, new_fs ? new_fs : current->fs); | |
1483 | if (!*new_nsp) | |
1484 | return -ENOMEM; | |
1485 | } | |
cf2e340f JD |
1486 | |
1487 | return 0; | |
1488 | } | |
1489 | ||
1490 | /* | |
1491 | * Unsharing of sighand for tasks created with CLONE_SIGHAND is not | |
1492 | * supported yet | |
1493 | */ | |
1494 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1495 | { | |
1496 | struct sighand_struct *sigh = current->sighand; | |
1497 | ||
1498 | if ((unshare_flags & CLONE_SIGHAND) && | |
1499 | (sigh && atomic_read(&sigh->count) > 1)) | |
1500 | return -EINVAL; | |
1501 | else | |
1502 | return 0; | |
1503 | } | |
1504 | ||
1505 | /* | |
a0a7ec30 | 1506 | * Unshare vm if it is being shared |
cf2e340f JD |
1507 | */ |
1508 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1509 | { | |
1510 | struct mm_struct *mm = current->mm; | |
1511 | ||
1512 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1513 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1514 | return -EINVAL; |
a0a7ec30 | 1515 | } |
cf2e340f JD |
1516 | |
1517 | return 0; | |
cf2e340f JD |
1518 | } |
1519 | ||
1520 | /* | |
a016f338 | 1521 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1522 | */ |
1523 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1524 | { | |
1525 | struct files_struct *fd = current->files; | |
a016f338 | 1526 | int error = 0; |
cf2e340f JD |
1527 | |
1528 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1529 | (fd && atomic_read(&fd->count) > 1)) { |
1530 | *new_fdp = dup_fd(fd, &error); | |
1531 | if (!*new_fdp) | |
1532 | return error; | |
1533 | } | |
cf2e340f JD |
1534 | |
1535 | return 0; | |
1536 | } | |
1537 | ||
1538 | /* | |
1539 | * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not | |
1540 | * supported yet | |
1541 | */ | |
1542 | static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp) | |
1543 | { | |
1544 | if (unshare_flags & CLONE_SYSVSEM) | |
1545 | return -EINVAL; | |
1546 | ||
1547 | return 0; | |
1548 | } | |
1549 | ||
1550 | /* | |
1551 | * unshare allows a process to 'unshare' part of the process | |
1552 | * context which was originally shared using clone. copy_* | |
1553 | * functions used by do_fork() cannot be used here directly | |
1554 | * because they modify an inactive task_struct that is being | |
1555 | * constructed. Here we are modifying the current, active, | |
1556 | * task_struct. | |
1557 | */ | |
1558 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1559 | { | |
1560 | int err = 0; | |
1561 | struct fs_struct *fs, *new_fs = NULL; | |
1562 | struct namespace *ns, *new_ns = NULL; | |
1563 | struct sighand_struct *sigh, *new_sigh = NULL; | |
1564 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; | |
1565 | struct files_struct *fd, *new_fd = NULL; | |
1566 | struct sem_undo_list *new_ulist = NULL; | |
1567 | ||
1568 | check_unshare_flags(&unshare_flags); | |
1569 | ||
06f9d4f9 EB |
1570 | /* Return -EINVAL for all unsupported flags */ |
1571 | err = -EINVAL; | |
1572 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
1573 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM)) | |
1574 | goto bad_unshare_out; | |
1575 | ||
cf2e340f JD |
1576 | if ((err = unshare_thread(unshare_flags))) |
1577 | goto bad_unshare_out; | |
1578 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1579 | goto bad_unshare_cleanup_thread; | |
741a2951 | 1580 | if ((err = unshare_namespace(unshare_flags, &new_ns, new_fs))) |
cf2e340f JD |
1581 | goto bad_unshare_cleanup_fs; |
1582 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) | |
1583 | goto bad_unshare_cleanup_ns; | |
1584 | if ((err = unshare_vm(unshare_flags, &new_mm))) | |
1585 | goto bad_unshare_cleanup_sigh; | |
1586 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1587 | goto bad_unshare_cleanup_vm; | |
1588 | if ((err = unshare_semundo(unshare_flags, &new_ulist))) | |
1589 | goto bad_unshare_cleanup_fd; | |
1590 | ||
1591 | if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) { | |
1592 | ||
1593 | task_lock(current); | |
1594 | ||
1595 | if (new_fs) { | |
1596 | fs = current->fs; | |
1597 | current->fs = new_fs; | |
1598 | new_fs = fs; | |
1599 | } | |
1600 | ||
1601 | if (new_ns) { | |
1602 | ns = current->namespace; | |
1603 | current->namespace = new_ns; | |
1604 | new_ns = ns; | |
1605 | } | |
1606 | ||
1607 | if (new_sigh) { | |
1608 | sigh = current->sighand; | |
e0e8eb54 | 1609 | rcu_assign_pointer(current->sighand, new_sigh); |
cf2e340f JD |
1610 | new_sigh = sigh; |
1611 | } | |
1612 | ||
1613 | if (new_mm) { | |
1614 | mm = current->mm; | |
1615 | active_mm = current->active_mm; | |
1616 | current->mm = new_mm; | |
1617 | current->active_mm = new_mm; | |
1618 | activate_mm(active_mm, new_mm); | |
1619 | new_mm = mm; | |
1620 | } | |
1621 | ||
1622 | if (new_fd) { | |
1623 | fd = current->files; | |
1624 | current->files = new_fd; | |
1625 | new_fd = fd; | |
1626 | } | |
1627 | ||
1628 | task_unlock(current); | |
1629 | } | |
1630 | ||
1631 | bad_unshare_cleanup_fd: | |
1632 | if (new_fd) | |
1633 | put_files_struct(new_fd); | |
1634 | ||
1635 | bad_unshare_cleanup_vm: | |
1636 | if (new_mm) | |
1637 | mmput(new_mm); | |
1638 | ||
1639 | bad_unshare_cleanup_sigh: | |
1640 | if (new_sigh) | |
1641 | if (atomic_dec_and_test(&new_sigh->count)) | |
1642 | kmem_cache_free(sighand_cachep, new_sigh); | |
1643 | ||
1644 | bad_unshare_cleanup_ns: | |
1645 | if (new_ns) | |
1646 | put_namespace(new_ns); | |
1647 | ||
1648 | bad_unshare_cleanup_fs: | |
1649 | if (new_fs) | |
1650 | put_fs_struct(new_fs); | |
1651 | ||
1652 | bad_unshare_cleanup_thread: | |
1653 | bad_unshare_out: | |
1654 | return err; | |
1655 | } |