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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 | ||
1da177e4 LT |
14 | #include <linux/slab.h> |
15 | #include <linux/init.h> | |
16 | #include <linux/unistd.h> | |
17 | #include <linux/smp_lock.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/vmalloc.h> | |
20 | #include <linux/completion.h> | |
21 | #include <linux/namespace.h> | |
22 | #include <linux/personality.h> | |
23 | #include <linux/mempolicy.h> | |
24 | #include <linux/sem.h> | |
25 | #include <linux/file.h> | |
26 | #include <linux/key.h> | |
27 | #include <linux/binfmts.h> | |
28 | #include <linux/mman.h> | |
29 | #include <linux/fs.h> | |
c59ede7b | 30 | #include <linux/capability.h> |
1da177e4 LT |
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> | |
9f46080c | 45 | #include <linux/cn_proc.h> |
1da177e4 LT |
46 | |
47 | #include <asm/pgtable.h> | |
48 | #include <asm/pgalloc.h> | |
49 | #include <asm/uaccess.h> | |
50 | #include <asm/mmu_context.h> | |
51 | #include <asm/cacheflush.h> | |
52 | #include <asm/tlbflush.h> | |
53 | ||
54 | /* | |
55 | * Protected counters by write_lock_irq(&tasklist_lock) | |
56 | */ | |
57 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
58 | int nr_threads; /* The idle threads do not count.. */ | |
59 | ||
60 | int max_threads; /* tunable limit on nr_threads */ | |
61 | ||
62 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
63 | ||
64 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ | |
65 | ||
66 | EXPORT_SYMBOL(tasklist_lock); | |
67 | ||
68 | int nr_processes(void) | |
69 | { | |
70 | int cpu; | |
71 | int total = 0; | |
72 | ||
73 | for_each_online_cpu(cpu) | |
74 | total += per_cpu(process_counts, cpu); | |
75 | ||
76 | return total; | |
77 | } | |
78 | ||
79 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
80 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
81 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
82 | static kmem_cache_t *task_struct_cachep; | |
83 | #endif | |
84 | ||
85 | /* SLAB cache for signal_struct structures (tsk->signal) */ | |
6b3934ef | 86 | static kmem_cache_t *signal_cachep; |
1da177e4 LT |
87 | |
88 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
89 | kmem_cache_t *sighand_cachep; | |
90 | ||
91 | /* SLAB cache for files_struct structures (tsk->files) */ | |
92 | kmem_cache_t *files_cachep; | |
93 | ||
94 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
95 | kmem_cache_t *fs_cachep; | |
96 | ||
97 | /* SLAB cache for vm_area_struct structures */ | |
98 | kmem_cache_t *vm_area_cachep; | |
99 | ||
100 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
101 | static kmem_cache_t *mm_cachep; | |
102 | ||
103 | void free_task(struct task_struct *tsk) | |
104 | { | |
105 | free_thread_info(tsk->thread_info); | |
23f78d4a | 106 | rt_mutex_debug_task_free(tsk); |
1da177e4 LT |
107 | free_task_struct(tsk); |
108 | } | |
109 | EXPORT_SYMBOL(free_task); | |
110 | ||
158d9ebd | 111 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 LT |
112 | { |
113 | WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE))); | |
114 | WARN_ON(atomic_read(&tsk->usage)); | |
115 | WARN_ON(tsk == current); | |
116 | ||
1da177e4 LT |
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 | ||
1da177e4 LT |
173 | *tsk = *orig; |
174 | tsk->thread_info = ti; | |
10ebffde | 175 | setup_thread_stack(tsk, orig); |
1da177e4 LT |
176 | |
177 | /* One for us, one for whoever does the "release_task()" (usually parent) */ | |
178 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 179 | atomic_set(&tsk->fs_excl, 0); |
2056a782 | 180 | tsk->btrace_seq = 0; |
a0aa7f68 | 181 | tsk->splice_pipe = NULL; |
1da177e4 LT |
182 | return tsk; |
183 | } | |
184 | ||
185 | #ifdef CONFIG_MMU | |
fd3e42fc | 186 | static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 187 | { |
fd3e42fc | 188 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
189 | struct rb_node **rb_link, *rb_parent; |
190 | int retval; | |
191 | unsigned long charge; | |
192 | struct mempolicy *pol; | |
193 | ||
194 | down_write(&oldmm->mmap_sem); | |
fd3e42fc | 195 | flush_cache_mm(oldmm); |
7ee78232 HD |
196 | down_write(&mm->mmap_sem); |
197 | ||
1da177e4 LT |
198 | mm->locked_vm = 0; |
199 | mm->mmap = NULL; | |
200 | mm->mmap_cache = NULL; | |
201 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 202 | mm->cached_hole_size = ~0UL; |
1da177e4 | 203 | mm->map_count = 0; |
1da177e4 LT |
204 | cpus_clear(mm->cpu_vm_mask); |
205 | mm->mm_rb = RB_ROOT; | |
206 | rb_link = &mm->mm_rb.rb_node; | |
207 | rb_parent = NULL; | |
208 | pprev = &mm->mmap; | |
209 | ||
fd3e42fc | 210 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
211 | struct file *file; |
212 | ||
213 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
214 | long pages = vma_pages(mpnt); |
215 | mm->total_vm -= pages; | |
ab50b8ed | 216 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 217 | -pages); |
1da177e4 LT |
218 | continue; |
219 | } | |
220 | charge = 0; | |
221 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
222 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
223 | if (security_vm_enough_memory(len)) | |
224 | goto fail_nomem; | |
225 | charge = len; | |
226 | } | |
227 | tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); | |
228 | if (!tmp) | |
229 | goto fail_nomem; | |
230 | *tmp = *mpnt; | |
231 | pol = mpol_copy(vma_policy(mpnt)); | |
232 | retval = PTR_ERR(pol); | |
233 | if (IS_ERR(pol)) | |
234 | goto fail_nomem_policy; | |
235 | vma_set_policy(tmp, pol); | |
236 | tmp->vm_flags &= ~VM_LOCKED; | |
237 | tmp->vm_mm = mm; | |
238 | tmp->vm_next = NULL; | |
239 | anon_vma_link(tmp); | |
240 | file = tmp->vm_file; | |
241 | if (file) { | |
242 | struct inode *inode = file->f_dentry->d_inode; | |
243 | get_file(file); | |
244 | if (tmp->vm_flags & VM_DENYWRITE) | |
245 | atomic_dec(&inode->i_writecount); | |
246 | ||
247 | /* insert tmp into the share list, just after mpnt */ | |
248 | spin_lock(&file->f_mapping->i_mmap_lock); | |
249 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
250 | flush_dcache_mmap_lock(file->f_mapping); | |
251 | vma_prio_tree_add(tmp, mpnt); | |
252 | flush_dcache_mmap_unlock(file->f_mapping); | |
253 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
254 | } | |
255 | ||
256 | /* | |
7ee78232 | 257 | * Link in the new vma and copy the page table entries. |
1da177e4 | 258 | */ |
1da177e4 LT |
259 | *pprev = tmp; |
260 | pprev = &tmp->vm_next; | |
261 | ||
262 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
263 | rb_link = &tmp->vm_rb.rb_right; | |
264 | rb_parent = &tmp->vm_rb; | |
265 | ||
266 | mm->map_count++; | |
0b0db14c | 267 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
268 | |
269 | if (tmp->vm_ops && tmp->vm_ops->open) | |
270 | tmp->vm_ops->open(tmp); | |
271 | ||
272 | if (retval) | |
273 | goto out; | |
274 | } | |
275 | retval = 0; | |
1da177e4 | 276 | out: |
7ee78232 | 277 | up_write(&mm->mmap_sem); |
fd3e42fc | 278 | flush_tlb_mm(oldmm); |
1da177e4 LT |
279 | up_write(&oldmm->mmap_sem); |
280 | return retval; | |
281 | fail_nomem_policy: | |
282 | kmem_cache_free(vm_area_cachep, tmp); | |
283 | fail_nomem: | |
284 | retval = -ENOMEM; | |
285 | vm_unacct_memory(charge); | |
286 | goto out; | |
287 | } | |
288 | ||
289 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
290 | { | |
291 | mm->pgd = pgd_alloc(mm); | |
292 | if (unlikely(!mm->pgd)) | |
293 | return -ENOMEM; | |
294 | return 0; | |
295 | } | |
296 | ||
297 | static inline void mm_free_pgd(struct mm_struct * mm) | |
298 | { | |
299 | pgd_free(mm->pgd); | |
300 | } | |
301 | #else | |
302 | #define dup_mmap(mm, oldmm) (0) | |
303 | #define mm_alloc_pgd(mm) (0) | |
304 | #define mm_free_pgd(mm) | |
305 | #endif /* CONFIG_MMU */ | |
306 | ||
307 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); | |
308 | ||
309 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL)) | |
310 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
311 | ||
312 | #include <linux/init_task.h> | |
313 | ||
314 | static struct mm_struct * mm_init(struct mm_struct * mm) | |
315 | { | |
316 | atomic_set(&mm->mm_users, 1); | |
317 | atomic_set(&mm->mm_count, 1); | |
318 | init_rwsem(&mm->mmap_sem); | |
319 | INIT_LIST_HEAD(&mm->mmlist); | |
320 | mm->core_waiters = 0; | |
321 | mm->nr_ptes = 0; | |
4294621f | 322 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 323 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
324 | spin_lock_init(&mm->page_table_lock); |
325 | rwlock_init(&mm->ioctx_list_lock); | |
326 | mm->ioctx_list = NULL; | |
1da177e4 | 327 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 328 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
329 | |
330 | if (likely(!mm_alloc_pgd(mm))) { | |
331 | mm->def_flags = 0; | |
332 | return mm; | |
333 | } | |
334 | free_mm(mm); | |
335 | return NULL; | |
336 | } | |
337 | ||
338 | /* | |
339 | * Allocate and initialize an mm_struct. | |
340 | */ | |
341 | struct mm_struct * mm_alloc(void) | |
342 | { | |
343 | struct mm_struct * mm; | |
344 | ||
345 | mm = allocate_mm(); | |
346 | if (mm) { | |
347 | memset(mm, 0, sizeof(*mm)); | |
348 | mm = mm_init(mm); | |
349 | } | |
350 | return mm; | |
351 | } | |
352 | ||
353 | /* | |
354 | * Called when the last reference to the mm | |
355 | * is dropped: either by a lazy thread or by | |
356 | * mmput. Free the page directory and the mm. | |
357 | */ | |
358 | void fastcall __mmdrop(struct mm_struct *mm) | |
359 | { | |
360 | BUG_ON(mm == &init_mm); | |
361 | mm_free_pgd(mm); | |
362 | destroy_context(mm); | |
363 | free_mm(mm); | |
364 | } | |
365 | ||
366 | /* | |
367 | * Decrement the use count and release all resources for an mm. | |
368 | */ | |
369 | void mmput(struct mm_struct *mm) | |
370 | { | |
0ae26f1b AM |
371 | might_sleep(); |
372 | ||
1da177e4 LT |
373 | if (atomic_dec_and_test(&mm->mm_users)) { |
374 | exit_aio(mm); | |
375 | exit_mmap(mm); | |
376 | if (!list_empty(&mm->mmlist)) { | |
377 | spin_lock(&mmlist_lock); | |
378 | list_del(&mm->mmlist); | |
379 | spin_unlock(&mmlist_lock); | |
380 | } | |
381 | put_swap_token(mm); | |
382 | mmdrop(mm); | |
383 | } | |
384 | } | |
385 | EXPORT_SYMBOL_GPL(mmput); | |
386 | ||
387 | /** | |
388 | * get_task_mm - acquire a reference to the task's mm | |
389 | * | |
390 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning | |
391 | * this kernel workthread has transiently adopted a user mm with use_mm, | |
392 | * to do its AIO) is not set and if so returns a reference to it, after | |
393 | * bumping up the use count. User must release the mm via mmput() | |
394 | * after use. Typically used by /proc and ptrace. | |
395 | */ | |
396 | struct mm_struct *get_task_mm(struct task_struct *task) | |
397 | { | |
398 | struct mm_struct *mm; | |
399 | ||
400 | task_lock(task); | |
401 | mm = task->mm; | |
402 | if (mm) { | |
403 | if (task->flags & PF_BORROWED_MM) | |
404 | mm = NULL; | |
405 | else | |
406 | atomic_inc(&mm->mm_users); | |
407 | } | |
408 | task_unlock(task); | |
409 | return mm; | |
410 | } | |
411 | EXPORT_SYMBOL_GPL(get_task_mm); | |
412 | ||
413 | /* Please note the differences between mmput and mm_release. | |
414 | * mmput is called whenever we stop holding onto a mm_struct, | |
415 | * error success whatever. | |
416 | * | |
417 | * mm_release is called after a mm_struct has been removed | |
418 | * from the current process. | |
419 | * | |
420 | * This difference is important for error handling, when we | |
421 | * only half set up a mm_struct for a new process and need to restore | |
422 | * the old one. Because we mmput the new mm_struct before | |
423 | * restoring the old one. . . | |
424 | * Eric Biederman 10 January 1998 | |
425 | */ | |
426 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
427 | { | |
428 | struct completion *vfork_done = tsk->vfork_done; | |
429 | ||
430 | /* Get rid of any cached register state */ | |
431 | deactivate_mm(tsk, mm); | |
432 | ||
433 | /* notify parent sleeping on vfork() */ | |
434 | if (vfork_done) { | |
435 | tsk->vfork_done = NULL; | |
436 | complete(vfork_done); | |
437 | } | |
438 | if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) { | |
439 | u32 __user * tidptr = tsk->clear_child_tid; | |
440 | tsk->clear_child_tid = NULL; | |
441 | ||
442 | /* | |
443 | * We don't check the error code - if userspace has | |
444 | * not set up a proper pointer then tough luck. | |
445 | */ | |
446 | put_user(0, tidptr); | |
447 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
448 | } | |
449 | } | |
450 | ||
a0a7ec30 JD |
451 | /* |
452 | * Allocate a new mm structure and copy contents from the | |
453 | * mm structure of the passed in task structure. | |
454 | */ | |
455 | static struct mm_struct *dup_mm(struct task_struct *tsk) | |
456 | { | |
457 | struct mm_struct *mm, *oldmm = current->mm; | |
458 | int err; | |
459 | ||
460 | if (!oldmm) | |
461 | return NULL; | |
462 | ||
463 | mm = allocate_mm(); | |
464 | if (!mm) | |
465 | goto fail_nomem; | |
466 | ||
467 | memcpy(mm, oldmm, sizeof(*mm)); | |
468 | ||
469 | if (!mm_init(mm)) | |
470 | goto fail_nomem; | |
471 | ||
472 | if (init_new_context(tsk, mm)) | |
473 | goto fail_nocontext; | |
474 | ||
475 | err = dup_mmap(mm, oldmm); | |
476 | if (err) | |
477 | goto free_pt; | |
478 | ||
479 | mm->hiwater_rss = get_mm_rss(mm); | |
480 | mm->hiwater_vm = mm->total_vm; | |
481 | ||
482 | return mm; | |
483 | ||
484 | free_pt: | |
485 | mmput(mm); | |
486 | ||
487 | fail_nomem: | |
488 | return NULL; | |
489 | ||
490 | fail_nocontext: | |
491 | /* | |
492 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
493 | * because it calls destroy_context() | |
494 | */ | |
495 | mm_free_pgd(mm); | |
496 | free_mm(mm); | |
497 | return NULL; | |
498 | } | |
499 | ||
1da177e4 LT |
500 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
501 | { | |
502 | struct mm_struct * mm, *oldmm; | |
503 | int retval; | |
504 | ||
505 | tsk->min_flt = tsk->maj_flt = 0; | |
506 | tsk->nvcsw = tsk->nivcsw = 0; | |
507 | ||
508 | tsk->mm = NULL; | |
509 | tsk->active_mm = NULL; | |
510 | ||
511 | /* | |
512 | * Are we cloning a kernel thread? | |
513 | * | |
514 | * We need to steal a active VM for that.. | |
515 | */ | |
516 | oldmm = current->mm; | |
517 | if (!oldmm) | |
518 | return 0; | |
519 | ||
520 | if (clone_flags & CLONE_VM) { | |
521 | atomic_inc(&oldmm->mm_users); | |
522 | mm = oldmm; | |
1da177e4 LT |
523 | goto good_mm; |
524 | } | |
525 | ||
526 | retval = -ENOMEM; | |
a0a7ec30 | 527 | mm = dup_mm(tsk); |
1da177e4 LT |
528 | if (!mm) |
529 | goto fail_nomem; | |
530 | ||
1da177e4 LT |
531 | good_mm: |
532 | tsk->mm = mm; | |
533 | tsk->active_mm = mm; | |
534 | return 0; | |
535 | ||
1da177e4 LT |
536 | fail_nomem: |
537 | return retval; | |
1da177e4 LT |
538 | } |
539 | ||
540 | static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old) | |
541 | { | |
542 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
543 | /* We don't need to lock fs - think why ;-) */ | |
544 | if (fs) { | |
545 | atomic_set(&fs->count, 1); | |
546 | rwlock_init(&fs->lock); | |
547 | fs->umask = old->umask; | |
548 | read_lock(&old->lock); | |
549 | fs->rootmnt = mntget(old->rootmnt); | |
550 | fs->root = dget(old->root); | |
551 | fs->pwdmnt = mntget(old->pwdmnt); | |
552 | fs->pwd = dget(old->pwd); | |
553 | if (old->altroot) { | |
554 | fs->altrootmnt = mntget(old->altrootmnt); | |
555 | fs->altroot = dget(old->altroot); | |
556 | } else { | |
557 | fs->altrootmnt = NULL; | |
558 | fs->altroot = NULL; | |
559 | } | |
560 | read_unlock(&old->lock); | |
561 | } | |
562 | return fs; | |
563 | } | |
564 | ||
565 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
566 | { | |
567 | return __copy_fs_struct(old); | |
568 | } | |
569 | ||
570 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
571 | ||
572 | static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk) | |
573 | { | |
574 | if (clone_flags & CLONE_FS) { | |
575 | atomic_inc(¤t->fs->count); | |
576 | return 0; | |
577 | } | |
578 | tsk->fs = __copy_fs_struct(current->fs); | |
579 | if (!tsk->fs) | |
580 | return -ENOMEM; | |
581 | return 0; | |
582 | } | |
583 | ||
ab2af1f5 | 584 | static int count_open_files(struct fdtable *fdt) |
1da177e4 | 585 | { |
ab2af1f5 | 586 | int size = fdt->max_fdset; |
1da177e4 LT |
587 | int i; |
588 | ||
589 | /* Find the last open fd */ | |
590 | for (i = size/(8*sizeof(long)); i > 0; ) { | |
badf1662 | 591 | if (fdt->open_fds->fds_bits[--i]) |
1da177e4 LT |
592 | break; |
593 | } | |
594 | i = (i+1) * 8 * sizeof(long); | |
595 | return i; | |
596 | } | |
597 | ||
badf1662 DS |
598 | static struct files_struct *alloc_files(void) |
599 | { | |
600 | struct files_struct *newf; | |
601 | struct fdtable *fdt; | |
602 | ||
603 | newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL); | |
604 | if (!newf) | |
605 | goto out; | |
606 | ||
607 | atomic_set(&newf->count, 1); | |
608 | ||
609 | spin_lock_init(&newf->file_lock); | |
0c9e63fd | 610 | newf->next_fd = 0; |
ab2af1f5 | 611 | fdt = &newf->fdtab; |
badf1662 | 612 | fdt->max_fds = NR_OPEN_DEFAULT; |
0c9e63fd ED |
613 | fdt->max_fdset = EMBEDDED_FD_SET_SIZE; |
614 | fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init; | |
615 | fdt->open_fds = (fd_set *)&newf->open_fds_init; | |
badf1662 | 616 | fdt->fd = &newf->fd_array[0]; |
ab2af1f5 DS |
617 | INIT_RCU_HEAD(&fdt->rcu); |
618 | fdt->free_files = NULL; | |
619 | fdt->next = NULL; | |
620 | rcu_assign_pointer(newf->fdt, fdt); | |
badf1662 DS |
621 | out: |
622 | return newf; | |
623 | } | |
624 | ||
a016f338 JD |
625 | /* |
626 | * Allocate a new files structure and copy contents from the | |
627 | * passed in files structure. | |
6e667260 | 628 | * errorp will be valid only when the returned files_struct is NULL. |
a016f338 JD |
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 | |
6e667260 | 637 | *errorp = -ENOMEM; |
badf1662 DS |
638 | newf = alloc_files(); |
639 | if (!newf) | |
1da177e4 LT |
640 | goto out; |
641 | ||
1da177e4 | 642 | spin_lock(&oldf->file_lock); |
badf1662 DS |
643 | old_fdt = files_fdtable(oldf); |
644 | new_fdt = files_fdtable(newf); | |
645 | size = old_fdt->max_fdset; | |
ab2af1f5 | 646 | open_files = count_open_files(old_fdt); |
1da177e4 LT |
647 | expand = 0; |
648 | ||
649 | /* | |
650 | * Check whether we need to allocate a larger fd array or fd set. | |
651 | * Note: we're not a clone task, so the open count won't change. | |
652 | */ | |
badf1662 DS |
653 | if (open_files > new_fdt->max_fdset) { |
654 | new_fdt->max_fdset = 0; | |
1da177e4 LT |
655 | expand = 1; |
656 | } | |
badf1662 DS |
657 | if (open_files > new_fdt->max_fds) { |
658 | new_fdt->max_fds = 0; | |
1da177e4 LT |
659 | expand = 1; |
660 | } | |
661 | ||
662 | /* if the old fdset gets grown now, we'll only copy up to "size" fds */ | |
663 | if (expand) { | |
664 | spin_unlock(&oldf->file_lock); | |
665 | spin_lock(&newf->file_lock); | |
a016f338 | 666 | *errorp = expand_files(newf, open_files-1); |
1da177e4 | 667 | spin_unlock(&newf->file_lock); |
a016f338 | 668 | if (*errorp < 0) |
1da177e4 | 669 | goto out_release; |
ab2af1f5 DS |
670 | new_fdt = files_fdtable(newf); |
671 | /* | |
672 | * Reacquire the oldf lock and a pointer to its fd table | |
673 | * who knows it may have a new bigger fd table. We need | |
674 | * the latest pointer. | |
675 | */ | |
1da177e4 | 676 | spin_lock(&oldf->file_lock); |
ab2af1f5 | 677 | old_fdt = files_fdtable(oldf); |
1da177e4 LT |
678 | } |
679 | ||
badf1662 DS |
680 | old_fds = old_fdt->fd; |
681 | new_fds = new_fdt->fd; | |
1da177e4 | 682 | |
badf1662 DS |
683 | memcpy(new_fdt->open_fds->fds_bits, old_fdt->open_fds->fds_bits, open_files/8); |
684 | memcpy(new_fdt->close_on_exec->fds_bits, old_fdt->close_on_exec->fds_bits, open_files/8); | |
1da177e4 LT |
685 | |
686 | for (i = open_files; i != 0; i--) { | |
687 | struct file *f = *old_fds++; | |
688 | if (f) { | |
689 | get_file(f); | |
690 | } else { | |
691 | /* | |
692 | * The fd may be claimed in the fd bitmap but not yet | |
693 | * instantiated in the files array if a sibling thread | |
694 | * is partway through open(). So make sure that this | |
695 | * fd is available to the new process. | |
696 | */ | |
badf1662 | 697 | FD_CLR(open_files - i, new_fdt->open_fds); |
1da177e4 | 698 | } |
ab2af1f5 | 699 | rcu_assign_pointer(*new_fds++, f); |
1da177e4 LT |
700 | } |
701 | spin_unlock(&oldf->file_lock); | |
702 | ||
703 | /* compute the remainder to be cleared */ | |
badf1662 | 704 | size = (new_fdt->max_fds - open_files) * sizeof(struct file *); |
1da177e4 LT |
705 | |
706 | /* This is long word aligned thus could use a optimized version */ | |
707 | memset(new_fds, 0, size); | |
708 | ||
badf1662 DS |
709 | if (new_fdt->max_fdset > open_files) { |
710 | int left = (new_fdt->max_fdset-open_files)/8; | |
1da177e4 LT |
711 | int start = open_files / (8 * sizeof(unsigned long)); |
712 | ||
badf1662 DS |
713 | memset(&new_fdt->open_fds->fds_bits[start], 0, left); |
714 | memset(&new_fdt->close_on_exec->fds_bits[start], 0, left); | |
1da177e4 LT |
715 | } |
716 | ||
1da177e4 | 717 | out: |
a016f338 | 718 | return newf; |
1da177e4 LT |
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 | 724 | kmem_cache_free(files_cachep, newf); |
42862298 | 725 | return NULL; |
1da177e4 LT |
726 | } |
727 | ||
a016f338 JD |
728 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
729 | { | |
730 | struct files_struct *oldf, *newf; | |
731 | int error = 0; | |
732 | ||
733 | /* | |
734 | * A background process may not have any files ... | |
735 | */ | |
736 | oldf = current->files; | |
737 | if (!oldf) | |
738 | goto out; | |
739 | ||
740 | if (clone_flags & CLONE_FILES) { | |
741 | atomic_inc(&oldf->count); | |
742 | goto out; | |
743 | } | |
744 | ||
745 | /* | |
746 | * Note: we may be using current for both targets (See exec.c) | |
747 | * This works because we cache current->files (old) as oldf. Don't | |
748 | * break this. | |
749 | */ | |
750 | tsk->files = NULL; | |
a016f338 JD |
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 | ||
a7e5328a | 806 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 807 | { |
c81addc9 ON |
808 | if (atomic_dec_and_test(&sighand->count)) |
809 | kmem_cache_free(sighand_cachep, sighand); | |
810 | } | |
811 | ||
1da177e4 LT |
812 | static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk) |
813 | { | |
814 | struct signal_struct *sig; | |
815 | int ret; | |
816 | ||
817 | if (clone_flags & CLONE_THREAD) { | |
818 | atomic_inc(¤t->signal->count); | |
819 | atomic_inc(¤t->signal->live); | |
820 | return 0; | |
821 | } | |
822 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
823 | tsk->signal = sig; | |
824 | if (!sig) | |
825 | return -ENOMEM; | |
826 | ||
827 | ret = copy_thread_group_keys(tsk); | |
828 | if (ret < 0) { | |
829 | kmem_cache_free(signal_cachep, sig); | |
830 | return ret; | |
831 | } | |
832 | ||
833 | atomic_set(&sig->count, 1); | |
834 | atomic_set(&sig->live, 1); | |
835 | init_waitqueue_head(&sig->wait_chldexit); | |
836 | sig->flags = 0; | |
837 | sig->group_exit_code = 0; | |
838 | sig->group_exit_task = NULL; | |
839 | sig->group_stop_count = 0; | |
840 | sig->curr_target = NULL; | |
841 | init_sigpending(&sig->shared_pending); | |
842 | INIT_LIST_HEAD(&sig->posix_timers); | |
843 | ||
7978672c | 844 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL); |
2ff678b8 | 845 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 846 | sig->real_timer.function = it_real_fn; |
05cfb614 | 847 | sig->tsk = tsk; |
1da177e4 LT |
848 | |
849 | sig->it_virt_expires = cputime_zero; | |
850 | sig->it_virt_incr = cputime_zero; | |
851 | sig->it_prof_expires = cputime_zero; | |
852 | sig->it_prof_incr = cputime_zero; | |
853 | ||
1da177e4 LT |
854 | sig->leader = 0; /* session leadership doesn't inherit */ |
855 | sig->tty_old_pgrp = 0; | |
856 | ||
857 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
858 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; | |
859 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
860 | sig->sched_time = 0; | |
861 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
862 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
863 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
864 | ||
865 | task_lock(current->group_leader); | |
866 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
867 | task_unlock(current->group_leader); | |
868 | ||
869 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
870 | /* | |
871 | * New sole thread in the process gets an expiry time | |
872 | * of the whole CPU time limit. | |
873 | */ | |
874 | tsk->it_prof_expires = | |
875 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
876 | } | |
0e464814 | 877 | acct_init_pacct(&sig->pacct); |
1da177e4 LT |
878 | |
879 | return 0; | |
880 | } | |
881 | ||
6b3934ef ON |
882 | void __cleanup_signal(struct signal_struct *sig) |
883 | { | |
884 | exit_thread_group_keys(sig); | |
885 | kmem_cache_free(signal_cachep, sig); | |
886 | } | |
887 | ||
888 | static inline void cleanup_signal(struct task_struct *tsk) | |
889 | { | |
890 | struct signal_struct *sig = tsk->signal; | |
891 | ||
892 | atomic_dec(&sig->live); | |
893 | ||
894 | if (atomic_dec_and_test(&sig->count)) | |
895 | __cleanup_signal(sig); | |
896 | } | |
897 | ||
1da177e4 LT |
898 | static inline void copy_flags(unsigned long clone_flags, struct task_struct *p) |
899 | { | |
900 | unsigned long new_flags = p->flags; | |
901 | ||
d1209d04 | 902 | new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE); |
1da177e4 LT |
903 | new_flags |= PF_FORKNOEXEC; |
904 | if (!(clone_flags & CLONE_PTRACE)) | |
905 | p->ptrace = 0; | |
906 | p->flags = new_flags; | |
907 | } | |
908 | ||
909 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
910 | { | |
911 | current->clear_child_tid = tidptr; | |
912 | ||
913 | return current->pid; | |
914 | } | |
915 | ||
23f78d4a IM |
916 | static inline void rt_mutex_init_task(struct task_struct *p) |
917 | { | |
918 | #ifdef CONFIG_RT_MUTEXES | |
919 | spin_lock_init(&p->pi_lock); | |
920 | plist_head_init(&p->pi_waiters, &p->pi_lock); | |
921 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
922 | #endif |
923 | } | |
924 | ||
1da177e4 LT |
925 | /* |
926 | * This creates a new process as a copy of the old one, | |
927 | * but does not actually start it yet. | |
928 | * | |
929 | * It copies the registers, and all the appropriate | |
930 | * parts of the process environment (as per the clone | |
931 | * flags). The actual kick-off is left to the caller. | |
932 | */ | |
933 | static task_t *copy_process(unsigned long clone_flags, | |
934 | unsigned long stack_start, | |
935 | struct pt_regs *regs, | |
936 | unsigned long stack_size, | |
937 | int __user *parent_tidptr, | |
938 | int __user *child_tidptr, | |
939 | int pid) | |
940 | { | |
941 | int retval; | |
942 | struct task_struct *p = NULL; | |
943 | ||
944 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
945 | return ERR_PTR(-EINVAL); | |
946 | ||
947 | /* | |
948 | * Thread groups must share signals as well, and detached threads | |
949 | * can only be started up within the thread group. | |
950 | */ | |
951 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
952 | return ERR_PTR(-EINVAL); | |
953 | ||
954 | /* | |
955 | * Shared signal handlers imply shared VM. By way of the above, | |
956 | * thread groups also imply shared VM. Blocking this case allows | |
957 | * for various simplifications in other code. | |
958 | */ | |
959 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
960 | return ERR_PTR(-EINVAL); | |
961 | ||
962 | retval = security_task_create(clone_flags); | |
963 | if (retval) | |
964 | goto fork_out; | |
965 | ||
966 | retval = -ENOMEM; | |
967 | p = dup_task_struct(current); | |
968 | if (!p) | |
969 | goto fork_out; | |
970 | ||
de30a2b3 IM |
971 | #ifdef CONFIG_TRACE_IRQFLAGS |
972 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); | |
973 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
974 | #endif | |
1da177e4 LT |
975 | retval = -EAGAIN; |
976 | if (atomic_read(&p->user->processes) >= | |
977 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
978 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
979 | p->user != &root_user) | |
980 | goto bad_fork_free; | |
981 | } | |
982 | ||
983 | atomic_inc(&p->user->__count); | |
984 | atomic_inc(&p->user->processes); | |
985 | get_group_info(p->group_info); | |
986 | ||
987 | /* | |
988 | * If multiple threads are within copy_process(), then this check | |
989 | * triggers too late. This doesn't hurt, the check is only there | |
990 | * to stop root fork bombs. | |
991 | */ | |
992 | if (nr_threads >= max_threads) | |
993 | goto bad_fork_cleanup_count; | |
994 | ||
a1261f54 | 995 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
996 | goto bad_fork_cleanup_count; |
997 | ||
998 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
999 | goto bad_fork_cleanup_put_domain; | |
1000 | ||
1001 | p->did_exec = 0; | |
1002 | copy_flags(clone_flags, p); | |
1003 | p->pid = pid; | |
1004 | retval = -EFAULT; | |
1005 | if (clone_flags & CLONE_PARENT_SETTID) | |
1006 | if (put_user(p->pid, parent_tidptr)) | |
1007 | goto bad_fork_cleanup; | |
1008 | ||
1da177e4 LT |
1009 | INIT_LIST_HEAD(&p->children); |
1010 | INIT_LIST_HEAD(&p->sibling); | |
1011 | p->vfork_done = NULL; | |
1012 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
1013 | |
1014 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
1015 | init_sigpending(&p->pending); | |
1016 | ||
1017 | p->utime = cputime_zero; | |
1018 | p->stime = cputime_zero; | |
1019 | p->sched_time = 0; | |
1020 | p->rchar = 0; /* I/O counter: bytes read */ | |
1021 | p->wchar = 0; /* I/O counter: bytes written */ | |
1022 | p->syscr = 0; /* I/O counter: read syscalls */ | |
1023 | p->syscw = 0; /* I/O counter: write syscalls */ | |
1024 | acct_clear_integrals(p); | |
1025 | ||
1026 | p->it_virt_expires = cputime_zero; | |
1027 | p->it_prof_expires = cputime_zero; | |
1028 | p->it_sched_expires = 0; | |
1029 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1030 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1031 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1032 | ||
1033 | p->lock_depth = -1; /* -1 = no lock */ | |
1034 | do_posix_clock_monotonic_gettime(&p->start_time); | |
1035 | p->security = NULL; | |
1036 | p->io_context = NULL; | |
1037 | p->io_wait = NULL; | |
1038 | p->audit_context = NULL; | |
b4b26418 | 1039 | cpuset_fork(p); |
1da177e4 LT |
1040 | #ifdef CONFIG_NUMA |
1041 | p->mempolicy = mpol_copy(p->mempolicy); | |
1042 | if (IS_ERR(p->mempolicy)) { | |
1043 | retval = PTR_ERR(p->mempolicy); | |
1044 | p->mempolicy = NULL; | |
b4b26418 | 1045 | goto bad_fork_cleanup_cpuset; |
1da177e4 | 1046 | } |
c61afb18 | 1047 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1048 | #endif |
de30a2b3 IM |
1049 | #ifdef CONFIG_TRACE_IRQFLAGS |
1050 | p->irq_events = 0; | |
1051 | p->hardirqs_enabled = 0; | |
1052 | p->hardirq_enable_ip = 0; | |
1053 | p->hardirq_enable_event = 0; | |
1054 | p->hardirq_disable_ip = _THIS_IP_; | |
1055 | p->hardirq_disable_event = 0; | |
1056 | p->softirqs_enabled = 1; | |
1057 | p->softirq_enable_ip = _THIS_IP_; | |
1058 | p->softirq_enable_event = 0; | |
1059 | p->softirq_disable_ip = 0; | |
1060 | p->softirq_disable_event = 0; | |
1061 | p->hardirq_context = 0; | |
1062 | p->softirq_context = 0; | |
1063 | #endif | |
fbb9ce95 IM |
1064 | #ifdef CONFIG_LOCKDEP |
1065 | p->lockdep_depth = 0; /* no locks held yet */ | |
1066 | p->curr_chain_key = 0; | |
1067 | p->lockdep_recursion = 0; | |
1068 | #endif | |
1da177e4 | 1069 | |
23f78d4a IM |
1070 | rt_mutex_init_task(p); |
1071 | ||
408894ee IM |
1072 | #ifdef CONFIG_DEBUG_MUTEXES |
1073 | p->blocked_on = NULL; /* not blocked yet */ | |
1074 | #endif | |
1075 | ||
1da177e4 LT |
1076 | p->tgid = p->pid; |
1077 | if (clone_flags & CLONE_THREAD) | |
1078 | p->tgid = current->tgid; | |
1079 | ||
1080 | if ((retval = security_task_alloc(p))) | |
1081 | goto bad_fork_cleanup_policy; | |
1082 | if ((retval = audit_alloc(p))) | |
1083 | goto bad_fork_cleanup_security; | |
1084 | /* copy all the process information */ | |
1085 | if ((retval = copy_semundo(clone_flags, p))) | |
1086 | goto bad_fork_cleanup_audit; | |
1087 | if ((retval = copy_files(clone_flags, p))) | |
1088 | goto bad_fork_cleanup_semundo; | |
1089 | if ((retval = copy_fs(clone_flags, p))) | |
1090 | goto bad_fork_cleanup_files; | |
1091 | if ((retval = copy_sighand(clone_flags, p))) | |
1092 | goto bad_fork_cleanup_fs; | |
1093 | if ((retval = copy_signal(clone_flags, p))) | |
1094 | goto bad_fork_cleanup_sighand; | |
1095 | if ((retval = copy_mm(clone_flags, p))) | |
1096 | goto bad_fork_cleanup_signal; | |
1097 | if ((retval = copy_keys(clone_flags, p))) | |
1098 | goto bad_fork_cleanup_mm; | |
1099 | if ((retval = copy_namespace(clone_flags, p))) | |
1100 | goto bad_fork_cleanup_keys; | |
1101 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); | |
1102 | if (retval) | |
1103 | goto bad_fork_cleanup_namespace; | |
1104 | ||
1105 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; | |
1106 | /* | |
1107 | * Clear TID on mm_release()? | |
1108 | */ | |
1109 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
8f17d3a5 IM |
1110 | p->robust_list = NULL; |
1111 | #ifdef CONFIG_COMPAT | |
1112 | p->compat_robust_list = NULL; | |
1113 | #endif | |
c87e2837 IM |
1114 | INIT_LIST_HEAD(&p->pi_state_list); |
1115 | p->pi_state_cache = NULL; | |
1116 | ||
f9a3879a GM |
1117 | /* |
1118 | * sigaltstack should be cleared when sharing the same VM | |
1119 | */ | |
1120 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1121 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1122 | ||
1da177e4 LT |
1123 | /* |
1124 | * Syscall tracing should be turned off in the child regardless | |
1125 | * of CLONE_PTRACE. | |
1126 | */ | |
1127 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1128 | #ifdef TIF_SYSCALL_EMU |
1129 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1130 | #endif | |
1da177e4 LT |
1131 | |
1132 | /* Our parent execution domain becomes current domain | |
1133 | These must match for thread signalling to apply */ | |
1134 | ||
1135 | p->parent_exec_id = p->self_exec_id; | |
1136 | ||
1137 | /* ok, now we should be set up.. */ | |
1138 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1139 | p->pdeath_signal = 0; | |
1140 | p->exit_state = 0; | |
1141 | ||
1da177e4 LT |
1142 | /* |
1143 | * Ok, make it visible to the rest of the system. | |
1144 | * We dont wake it up yet. | |
1145 | */ | |
1146 | p->group_leader = p; | |
47e65328 | 1147 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 LT |
1148 | INIT_LIST_HEAD(&p->ptrace_children); |
1149 | INIT_LIST_HEAD(&p->ptrace_list); | |
1150 | ||
476d139c NP |
1151 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1152 | sched_fork(p, clone_flags); | |
1153 | ||
1da177e4 LT |
1154 | /* Need tasklist lock for parent etc handling! */ |
1155 | write_lock_irq(&tasklist_lock); | |
1156 | ||
1157 | /* | |
476d139c NP |
1158 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1159 | * not be changed, nor will its assigned CPU. | |
1160 | * | |
1161 | * The cpus_allowed mask of the parent may have changed after it was | |
1162 | * copied first time - so re-copy it here, then check the child's CPU | |
1163 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1164 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1165 | */ |
1166 | p->cpus_allowed = current->cpus_allowed; | |
26ff6ad9 SV |
1167 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1168 | !cpu_online(task_cpu(p)))) | |
476d139c | 1169 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1170 | |
1da177e4 LT |
1171 | /* CLONE_PARENT re-uses the old parent */ |
1172 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1173 | p->real_parent = current->real_parent; | |
1174 | else | |
1175 | p->real_parent = current; | |
1176 | p->parent = p->real_parent; | |
1177 | ||
3f17da69 | 1178 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1179 | |
1180 | /* | |
1181 | * Process group and session signals need to be delivered to just the | |
1182 | * parent before the fork or both the parent and the child after the | |
1183 | * fork. Restart if a signal comes in before we add the new process to | |
1184 | * it's process group. | |
1185 | * A fatal signal pending means that current will exit, so the new | |
1186 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1187 | */ | |
1188 | recalc_sigpending(); | |
1189 | if (signal_pending(current)) { | |
1190 | spin_unlock(¤t->sighand->siglock); | |
1191 | write_unlock_irq(&tasklist_lock); | |
1192 | retval = -ERESTARTNOINTR; | |
1193 | goto bad_fork_cleanup_namespace; | |
1194 | } | |
1195 | ||
1da177e4 | 1196 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1197 | p->group_leader = current->group_leader; |
47e65328 | 1198 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1199 | |
1da177e4 LT |
1200 | if (!cputime_eq(current->signal->it_virt_expires, |
1201 | cputime_zero) || | |
1202 | !cputime_eq(current->signal->it_prof_expires, | |
1203 | cputime_zero) || | |
1204 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1205 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1206 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1207 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1208 | /* | |
1209 | * Have child wake up on its first tick to check | |
1210 | * for process CPU timers. | |
1211 | */ | |
1212 | p->it_prof_expires = jiffies_to_cputime(1); | |
1213 | } | |
1da177e4 LT |
1214 | } |
1215 | ||
22e2c507 JA |
1216 | /* |
1217 | * inherit ioprio | |
1218 | */ | |
1219 | p->ioprio = current->ioprio; | |
1220 | ||
73b9ebfe ON |
1221 | if (likely(p->pid)) { |
1222 | add_parent(p); | |
1223 | if (unlikely(p->ptrace & PT_PTRACED)) | |
1224 | __ptrace_link(p, current->parent); | |
1225 | ||
1226 | if (thread_group_leader(p)) { | |
1227 | p->signal->tty = current->signal->tty; | |
1228 | p->signal->pgrp = process_group(current); | |
1229 | p->signal->session = current->signal->session; | |
1230 | attach_pid(p, PIDTYPE_PGID, process_group(p)); | |
1231 | attach_pid(p, PIDTYPE_SID, p->signal->session); | |
1232 | ||
5e85d4ab | 1233 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1234 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1235 | } |
73b9ebfe ON |
1236 | attach_pid(p, PIDTYPE_PID, p->pid); |
1237 | nr_threads++; | |
1da177e4 LT |
1238 | } |
1239 | ||
1da177e4 | 1240 | total_forks++; |
3f17da69 | 1241 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1242 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1243 | proc_fork_connector(p); |
1da177e4 LT |
1244 | return p; |
1245 | ||
1246 | bad_fork_cleanup_namespace: | |
1247 | exit_namespace(p); | |
1248 | bad_fork_cleanup_keys: | |
1249 | exit_keys(p); | |
1250 | bad_fork_cleanup_mm: | |
1251 | if (p->mm) | |
1252 | mmput(p->mm); | |
1253 | bad_fork_cleanup_signal: | |
6b3934ef | 1254 | cleanup_signal(p); |
1da177e4 | 1255 | bad_fork_cleanup_sighand: |
a7e5328a | 1256 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1257 | bad_fork_cleanup_fs: |
1258 | exit_fs(p); /* blocking */ | |
1259 | bad_fork_cleanup_files: | |
1260 | exit_files(p); /* blocking */ | |
1261 | bad_fork_cleanup_semundo: | |
1262 | exit_sem(p); | |
1263 | bad_fork_cleanup_audit: | |
1264 | audit_free(p); | |
1265 | bad_fork_cleanup_security: | |
1266 | security_task_free(p); | |
1267 | bad_fork_cleanup_policy: | |
1268 | #ifdef CONFIG_NUMA | |
1269 | mpol_free(p->mempolicy); | |
b4b26418 | 1270 | bad_fork_cleanup_cpuset: |
1da177e4 | 1271 | #endif |
b4b26418 | 1272 | cpuset_exit(p); |
1da177e4 LT |
1273 | bad_fork_cleanup: |
1274 | if (p->binfmt) | |
1275 | module_put(p->binfmt->module); | |
1276 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1277 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1278 | bad_fork_cleanup_count: |
1279 | put_group_info(p->group_info); | |
1280 | atomic_dec(&p->user->processes); | |
1281 | free_uid(p->user); | |
1282 | bad_fork_free: | |
1283 | free_task(p); | |
fe7d37d1 ON |
1284 | fork_out: |
1285 | return ERR_PTR(retval); | |
1da177e4 LT |
1286 | } |
1287 | ||
1288 | struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs) | |
1289 | { | |
1290 | memset(regs, 0, sizeof(struct pt_regs)); | |
1291 | return regs; | |
1292 | } | |
1293 | ||
1294 | task_t * __devinit fork_idle(int cpu) | |
1295 | { | |
1296 | task_t *task; | |
1297 | struct pt_regs regs; | |
1298 | ||
1299 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0); | |
1300 | if (!task) | |
1301 | return ERR_PTR(-ENOMEM); | |
1302 | init_idle(task, cpu); | |
73b9ebfe | 1303 | |
1da177e4 LT |
1304 | return task; |
1305 | } | |
1306 | ||
1307 | static inline int fork_traceflag (unsigned clone_flags) | |
1308 | { | |
1309 | if (clone_flags & CLONE_UNTRACED) | |
1310 | return 0; | |
1311 | else if (clone_flags & CLONE_VFORK) { | |
1312 | if (current->ptrace & PT_TRACE_VFORK) | |
1313 | return PTRACE_EVENT_VFORK; | |
1314 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1315 | if (current->ptrace & PT_TRACE_CLONE) | |
1316 | return PTRACE_EVENT_CLONE; | |
1317 | } else if (current->ptrace & PT_TRACE_FORK) | |
1318 | return PTRACE_EVENT_FORK; | |
1319 | ||
1320 | return 0; | |
1321 | } | |
1322 | ||
1323 | /* | |
1324 | * Ok, this is the main fork-routine. | |
1325 | * | |
1326 | * It copies the process, and if successful kick-starts | |
1327 | * it and waits for it to finish using the VM if required. | |
1328 | */ | |
1329 | long do_fork(unsigned long clone_flags, | |
1330 | unsigned long stack_start, | |
1331 | struct pt_regs *regs, | |
1332 | unsigned long stack_size, | |
1333 | int __user *parent_tidptr, | |
1334 | int __user *child_tidptr) | |
1335 | { | |
1336 | struct task_struct *p; | |
1337 | int trace = 0; | |
92476d7f EB |
1338 | struct pid *pid = alloc_pid(); |
1339 | long nr; | |
1da177e4 | 1340 | |
92476d7f | 1341 | if (!pid) |
1da177e4 | 1342 | return -EAGAIN; |
92476d7f | 1343 | nr = pid->nr; |
1da177e4 LT |
1344 | if (unlikely(current->ptrace)) { |
1345 | trace = fork_traceflag (clone_flags); | |
1346 | if (trace) | |
1347 | clone_flags |= CLONE_PTRACE; | |
1348 | } | |
1349 | ||
92476d7f | 1350 | p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, nr); |
1da177e4 LT |
1351 | /* |
1352 | * Do this prior waking up the new thread - the thread pointer | |
1353 | * might get invalid after that point, if the thread exits quickly. | |
1354 | */ | |
1355 | if (!IS_ERR(p)) { | |
1356 | struct completion vfork; | |
1357 | ||
1358 | if (clone_flags & CLONE_VFORK) { | |
1359 | p->vfork_done = &vfork; | |
1360 | init_completion(&vfork); | |
1361 | } | |
1362 | ||
1363 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1364 | /* | |
1365 | * We'll start up with an immediate SIGSTOP. | |
1366 | */ | |
1367 | sigaddset(&p->pending.signal, SIGSTOP); | |
1368 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1369 | } | |
1370 | ||
1371 | if (!(clone_flags & CLONE_STOPPED)) | |
1372 | wake_up_new_task(p, clone_flags); | |
1373 | else | |
1374 | p->state = TASK_STOPPED; | |
1375 | ||
1376 | if (unlikely (trace)) { | |
92476d7f | 1377 | current->ptrace_message = nr; |
1da177e4 LT |
1378 | ptrace_notify ((trace << 8) | SIGTRAP); |
1379 | } | |
1380 | ||
1381 | if (clone_flags & CLONE_VFORK) { | |
1382 | wait_for_completion(&vfork); | |
1383 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) | |
1384 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); | |
1385 | } | |
1386 | } else { | |
92476d7f EB |
1387 | free_pid(pid); |
1388 | nr = PTR_ERR(p); | |
1da177e4 | 1389 | } |
92476d7f | 1390 | return nr; |
1da177e4 LT |
1391 | } |
1392 | ||
5fd63b30 RT |
1393 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1394 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1395 | #endif | |
1396 | ||
aa1757f9 ON |
1397 | static void sighand_ctor(void *data, kmem_cache_t *cachep, unsigned long flags) |
1398 | { | |
1399 | struct sighand_struct *sighand = data; | |
1400 | ||
1401 | if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == | |
1402 | SLAB_CTOR_CONSTRUCTOR) | |
1403 | spin_lock_init(&sighand->siglock); | |
1404 | } | |
1405 | ||
1da177e4 LT |
1406 | void __init proc_caches_init(void) |
1407 | { | |
1408 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1409 | sizeof(struct sighand_struct), 0, | |
aa1757f9 ON |
1410 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
1411 | sighand_ctor, NULL); | |
1da177e4 LT |
1412 | signal_cachep = kmem_cache_create("signal_cache", |
1413 | sizeof(struct signal_struct), 0, | |
1414 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1415 | files_cachep = kmem_cache_create("files_cache", | |
1416 | sizeof(struct files_struct), 0, | |
1417 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1418 | fs_cachep = kmem_cache_create("fs_cache", | |
1419 | sizeof(struct fs_struct), 0, | |
1420 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1421 | vm_area_cachep = kmem_cache_create("vm_area_struct", | |
1422 | sizeof(struct vm_area_struct), 0, | |
1423 | SLAB_PANIC, NULL, NULL); | |
1424 | mm_cachep = kmem_cache_create("mm_struct", | |
5fd63b30 | 1425 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
1da177e4 LT |
1426 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
1427 | } | |
cf2e340f JD |
1428 | |
1429 | ||
1430 | /* | |
1431 | * Check constraints on flags passed to the unshare system call and | |
1432 | * force unsharing of additional process context as appropriate. | |
1433 | */ | |
1434 | static inline void check_unshare_flags(unsigned long *flags_ptr) | |
1435 | { | |
1436 | /* | |
1437 | * If unsharing a thread from a thread group, must also | |
1438 | * unshare vm. | |
1439 | */ | |
1440 | if (*flags_ptr & CLONE_THREAD) | |
1441 | *flags_ptr |= CLONE_VM; | |
1442 | ||
1443 | /* | |
1444 | * If unsharing vm, must also unshare signal handlers. | |
1445 | */ | |
1446 | if (*flags_ptr & CLONE_VM) | |
1447 | *flags_ptr |= CLONE_SIGHAND; | |
1448 | ||
1449 | /* | |
1450 | * If unsharing signal handlers and the task was created | |
1451 | * using CLONE_THREAD, then must unshare the thread | |
1452 | */ | |
1453 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1454 | (atomic_read(¤t->signal->count) > 1)) | |
1455 | *flags_ptr |= CLONE_THREAD; | |
1456 | ||
1457 | /* | |
1458 | * If unsharing namespace, must also unshare filesystem information. | |
1459 | */ | |
1460 | if (*flags_ptr & CLONE_NEWNS) | |
1461 | *flags_ptr |= CLONE_FS; | |
1462 | } | |
1463 | ||
1464 | /* | |
1465 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1466 | */ | |
1467 | static int unshare_thread(unsigned long unshare_flags) | |
1468 | { | |
1469 | if (unshare_flags & CLONE_THREAD) | |
1470 | return -EINVAL; | |
1471 | ||
1472 | return 0; | |
1473 | } | |
1474 | ||
1475 | /* | |
99d1419d | 1476 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1477 | */ |
1478 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1479 | { | |
1480 | struct fs_struct *fs = current->fs; | |
1481 | ||
1482 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1483 | (fs && atomic_read(&fs->count) > 1)) { |
1484 | *new_fsp = __copy_fs_struct(current->fs); | |
1485 | if (!*new_fsp) | |
1486 | return -ENOMEM; | |
1487 | } | |
cf2e340f JD |
1488 | |
1489 | return 0; | |
1490 | } | |
1491 | ||
1492 | /* | |
741a2951 | 1493 | * Unshare the namespace structure if it is being shared |
cf2e340f | 1494 | */ |
741a2951 | 1495 | static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs) |
cf2e340f JD |
1496 | { |
1497 | struct namespace *ns = current->namespace; | |
1498 | ||
1499 | if ((unshare_flags & CLONE_NEWNS) && | |
741a2951 JD |
1500 | (ns && atomic_read(&ns->count) > 1)) { |
1501 | if (!capable(CAP_SYS_ADMIN)) | |
1502 | return -EPERM; | |
1503 | ||
1504 | *new_nsp = dup_namespace(current, new_fs ? new_fs : current->fs); | |
1505 | if (!*new_nsp) | |
1506 | return -ENOMEM; | |
1507 | } | |
cf2e340f JD |
1508 | |
1509 | return 0; | |
1510 | } | |
1511 | ||
1512 | /* | |
1513 | * Unsharing of sighand for tasks created with CLONE_SIGHAND is not | |
1514 | * supported yet | |
1515 | */ | |
1516 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1517 | { | |
1518 | struct sighand_struct *sigh = current->sighand; | |
1519 | ||
1520 | if ((unshare_flags & CLONE_SIGHAND) && | |
1521 | (sigh && atomic_read(&sigh->count) > 1)) | |
1522 | return -EINVAL; | |
1523 | else | |
1524 | return 0; | |
1525 | } | |
1526 | ||
1527 | /* | |
a0a7ec30 | 1528 | * Unshare vm if it is being shared |
cf2e340f JD |
1529 | */ |
1530 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1531 | { | |
1532 | struct mm_struct *mm = current->mm; | |
1533 | ||
1534 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1535 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1536 | return -EINVAL; |
a0a7ec30 | 1537 | } |
cf2e340f JD |
1538 | |
1539 | return 0; | |
cf2e340f JD |
1540 | } |
1541 | ||
1542 | /* | |
a016f338 | 1543 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1544 | */ |
1545 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1546 | { | |
1547 | struct files_struct *fd = current->files; | |
a016f338 | 1548 | int error = 0; |
cf2e340f JD |
1549 | |
1550 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1551 | (fd && atomic_read(&fd->count) > 1)) { |
1552 | *new_fdp = dup_fd(fd, &error); | |
1553 | if (!*new_fdp) | |
1554 | return error; | |
1555 | } | |
cf2e340f JD |
1556 | |
1557 | return 0; | |
1558 | } | |
1559 | ||
1560 | /* | |
1561 | * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not | |
1562 | * supported yet | |
1563 | */ | |
1564 | static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp) | |
1565 | { | |
1566 | if (unshare_flags & CLONE_SYSVSEM) | |
1567 | return -EINVAL; | |
1568 | ||
1569 | return 0; | |
1570 | } | |
1571 | ||
1572 | /* | |
1573 | * unshare allows a process to 'unshare' part of the process | |
1574 | * context which was originally shared using clone. copy_* | |
1575 | * functions used by do_fork() cannot be used here directly | |
1576 | * because they modify an inactive task_struct that is being | |
1577 | * constructed. Here we are modifying the current, active, | |
1578 | * task_struct. | |
1579 | */ | |
1580 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1581 | { | |
1582 | int err = 0; | |
1583 | struct fs_struct *fs, *new_fs = NULL; | |
1584 | struct namespace *ns, *new_ns = NULL; | |
1585 | struct sighand_struct *sigh, *new_sigh = NULL; | |
1586 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; | |
1587 | struct files_struct *fd, *new_fd = NULL; | |
1588 | struct sem_undo_list *new_ulist = NULL; | |
1589 | ||
1590 | check_unshare_flags(&unshare_flags); | |
1591 | ||
06f9d4f9 EB |
1592 | /* Return -EINVAL for all unsupported flags */ |
1593 | err = -EINVAL; | |
1594 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
1595 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM)) | |
1596 | goto bad_unshare_out; | |
1597 | ||
cf2e340f JD |
1598 | if ((err = unshare_thread(unshare_flags))) |
1599 | goto bad_unshare_out; | |
1600 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1601 | goto bad_unshare_cleanup_thread; | |
741a2951 | 1602 | if ((err = unshare_namespace(unshare_flags, &new_ns, new_fs))) |
cf2e340f JD |
1603 | goto bad_unshare_cleanup_fs; |
1604 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) | |
1605 | goto bad_unshare_cleanup_ns; | |
1606 | if ((err = unshare_vm(unshare_flags, &new_mm))) | |
1607 | goto bad_unshare_cleanup_sigh; | |
1608 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1609 | goto bad_unshare_cleanup_vm; | |
1610 | if ((err = unshare_semundo(unshare_flags, &new_ulist))) | |
1611 | goto bad_unshare_cleanup_fd; | |
1612 | ||
1613 | if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) { | |
1614 | ||
1615 | task_lock(current); | |
1616 | ||
1617 | if (new_fs) { | |
1618 | fs = current->fs; | |
1619 | current->fs = new_fs; | |
1620 | new_fs = fs; | |
1621 | } | |
1622 | ||
1623 | if (new_ns) { | |
1624 | ns = current->namespace; | |
1625 | current->namespace = new_ns; | |
1626 | new_ns = ns; | |
1627 | } | |
1628 | ||
1629 | if (new_sigh) { | |
1630 | sigh = current->sighand; | |
e0e8eb54 | 1631 | rcu_assign_pointer(current->sighand, new_sigh); |
cf2e340f JD |
1632 | new_sigh = sigh; |
1633 | } | |
1634 | ||
1635 | if (new_mm) { | |
1636 | mm = current->mm; | |
1637 | active_mm = current->active_mm; | |
1638 | current->mm = new_mm; | |
1639 | current->active_mm = new_mm; | |
1640 | activate_mm(active_mm, new_mm); | |
1641 | new_mm = mm; | |
1642 | } | |
1643 | ||
1644 | if (new_fd) { | |
1645 | fd = current->files; | |
1646 | current->files = new_fd; | |
1647 | new_fd = fd; | |
1648 | } | |
1649 | ||
1650 | task_unlock(current); | |
1651 | } | |
1652 | ||
1653 | bad_unshare_cleanup_fd: | |
1654 | if (new_fd) | |
1655 | put_files_struct(new_fd); | |
1656 | ||
1657 | bad_unshare_cleanup_vm: | |
1658 | if (new_mm) | |
1659 | mmput(new_mm); | |
1660 | ||
1661 | bad_unshare_cleanup_sigh: | |
1662 | if (new_sigh) | |
1663 | if (atomic_dec_and_test(&new_sigh->count)) | |
1664 | kmem_cache_free(sighand_cachep, new_sigh); | |
1665 | ||
1666 | bad_unshare_cleanup_ns: | |
1667 | if (new_ns) | |
1668 | put_namespace(new_ns); | |
1669 | ||
1670 | bad_unshare_cleanup_fs: | |
1671 | if (new_fs) | |
1672 | put_fs_struct(new_fs); | |
1673 | ||
1674 | bad_unshare_cleanup_thread: | |
1675 | bad_unshare_out: | |
1676 | return err; | |
1677 | } |