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> | |
8f0ab514 | 45 | #include <linux/tsacct_kern.h> |
9f46080c | 46 | #include <linux/cn_proc.h> |
ca74e92b | 47 | #include <linux/delayacct.h> |
ad4ecbcb | 48 | #include <linux/taskstats_kern.h> |
0a425405 | 49 | #include <linux/random.h> |
1da177e4 LT |
50 | |
51 | #include <asm/pgtable.h> | |
52 | #include <asm/pgalloc.h> | |
53 | #include <asm/uaccess.h> | |
54 | #include <asm/mmu_context.h> | |
55 | #include <asm/cacheflush.h> | |
56 | #include <asm/tlbflush.h> | |
57 | ||
58 | /* | |
59 | * Protected counters by write_lock_irq(&tasklist_lock) | |
60 | */ | |
61 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
62 | int nr_threads; /* The idle threads do not count.. */ | |
63 | ||
64 | int max_threads; /* tunable limit on nr_threads */ | |
65 | ||
66 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
67 | ||
c59923a1 | 68 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
69 | |
70 | int nr_processes(void) | |
71 | { | |
72 | int cpu; | |
73 | int total = 0; | |
74 | ||
75 | for_each_online_cpu(cpu) | |
76 | total += per_cpu(process_counts, cpu); | |
77 | ||
78 | return total; | |
79 | } | |
80 | ||
81 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
82 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
83 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
84 | static kmem_cache_t *task_struct_cachep; | |
85 | #endif | |
86 | ||
87 | /* SLAB cache for signal_struct structures (tsk->signal) */ | |
6b3934ef | 88 | static kmem_cache_t *signal_cachep; |
1da177e4 LT |
89 | |
90 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
91 | kmem_cache_t *sighand_cachep; | |
92 | ||
93 | /* SLAB cache for files_struct structures (tsk->files) */ | |
94 | kmem_cache_t *files_cachep; | |
95 | ||
96 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
97 | kmem_cache_t *fs_cachep; | |
98 | ||
99 | /* SLAB cache for vm_area_struct structures */ | |
100 | kmem_cache_t *vm_area_cachep; | |
101 | ||
102 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
103 | static kmem_cache_t *mm_cachep; | |
104 | ||
105 | void free_task(struct task_struct *tsk) | |
106 | { | |
107 | free_thread_info(tsk->thread_info); | |
23f78d4a | 108 | rt_mutex_debug_task_free(tsk); |
1da177e4 LT |
109 | free_task_struct(tsk); |
110 | } | |
111 | EXPORT_SYMBOL(free_task); | |
112 | ||
158d9ebd | 113 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 LT |
114 | { |
115 | WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE))); | |
116 | WARN_ON(atomic_read(&tsk->usage)); | |
117 | WARN_ON(tsk == current); | |
118 | ||
1da177e4 LT |
119 | security_task_free(tsk); |
120 | free_uid(tsk->user); | |
121 | put_group_info(tsk->group_info); | |
35df17c5 | 122 | delayacct_tsk_free(tsk); |
1da177e4 LT |
123 | |
124 | if (!profile_handoff_task(tsk)) | |
125 | free_task(tsk); | |
126 | } | |
127 | ||
128 | void __init fork_init(unsigned long mempages) | |
129 | { | |
130 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
131 | #ifndef ARCH_MIN_TASKALIGN | |
132 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
133 | #endif | |
134 | /* create a slab on which task_structs can be allocated */ | |
135 | task_struct_cachep = | |
136 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
137 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL); | |
138 | #endif | |
139 | ||
140 | /* | |
141 | * The default maximum number of threads is set to a safe | |
142 | * value: the thread structures can take up at most half | |
143 | * of memory. | |
144 | */ | |
145 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
146 | ||
147 | /* | |
148 | * we need to allow at least 20 threads to boot a system | |
149 | */ | |
150 | if(max_threads < 20) | |
151 | max_threads = 20; | |
152 | ||
153 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
154 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
155 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
156 | init_task.signal->rlim[RLIMIT_NPROC]; | |
157 | } | |
158 | ||
159 | static struct task_struct *dup_task_struct(struct task_struct *orig) | |
160 | { | |
161 | struct task_struct *tsk; | |
162 | struct thread_info *ti; | |
163 | ||
164 | prepare_to_copy(orig); | |
165 | ||
166 | tsk = alloc_task_struct(); | |
167 | if (!tsk) | |
168 | return NULL; | |
169 | ||
170 | ti = alloc_thread_info(tsk); | |
171 | if (!ti) { | |
172 | free_task_struct(tsk); | |
173 | return NULL; | |
174 | } | |
175 | ||
1da177e4 LT |
176 | *tsk = *orig; |
177 | tsk->thread_info = ti; | |
10ebffde | 178 | setup_thread_stack(tsk, orig); |
1da177e4 | 179 | |
0a425405 AV |
180 | #ifdef CONFIG_CC_STACKPROTECTOR |
181 | tsk->stack_canary = get_random_int(); | |
182 | #endif | |
183 | ||
1da177e4 LT |
184 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
185 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 186 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 187 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 188 | tsk->btrace_seq = 0; |
6c5c9341 | 189 | #endif |
a0aa7f68 | 190 | tsk->splice_pipe = NULL; |
1da177e4 LT |
191 | return tsk; |
192 | } | |
193 | ||
194 | #ifdef CONFIG_MMU | |
fd3e42fc | 195 | static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 196 | { |
fd3e42fc | 197 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
198 | struct rb_node **rb_link, *rb_parent; |
199 | int retval; | |
200 | unsigned long charge; | |
201 | struct mempolicy *pol; | |
202 | ||
203 | down_write(&oldmm->mmap_sem); | |
fd3e42fc | 204 | flush_cache_mm(oldmm); |
ad339451 IM |
205 | /* |
206 | * Not linked in yet - no deadlock potential: | |
207 | */ | |
208 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 209 | |
1da177e4 LT |
210 | mm->locked_vm = 0; |
211 | mm->mmap = NULL; | |
212 | mm->mmap_cache = NULL; | |
213 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 214 | mm->cached_hole_size = ~0UL; |
1da177e4 | 215 | mm->map_count = 0; |
1da177e4 LT |
216 | cpus_clear(mm->cpu_vm_mask); |
217 | mm->mm_rb = RB_ROOT; | |
218 | rb_link = &mm->mm_rb.rb_node; | |
219 | rb_parent = NULL; | |
220 | pprev = &mm->mmap; | |
221 | ||
fd3e42fc | 222 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
223 | struct file *file; |
224 | ||
225 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
226 | long pages = vma_pages(mpnt); |
227 | mm->total_vm -= pages; | |
ab50b8ed | 228 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 229 | -pages); |
1da177e4 LT |
230 | continue; |
231 | } | |
232 | charge = 0; | |
233 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
234 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
235 | if (security_vm_enough_memory(len)) | |
236 | goto fail_nomem; | |
237 | charge = len; | |
238 | } | |
239 | tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); | |
240 | if (!tmp) | |
241 | goto fail_nomem; | |
242 | *tmp = *mpnt; | |
243 | pol = mpol_copy(vma_policy(mpnt)); | |
244 | retval = PTR_ERR(pol); | |
245 | if (IS_ERR(pol)) | |
246 | goto fail_nomem_policy; | |
247 | vma_set_policy(tmp, pol); | |
248 | tmp->vm_flags &= ~VM_LOCKED; | |
249 | tmp->vm_mm = mm; | |
250 | tmp->vm_next = NULL; | |
251 | anon_vma_link(tmp); | |
252 | file = tmp->vm_file; | |
253 | if (file) { | |
254 | struct inode *inode = file->f_dentry->d_inode; | |
255 | get_file(file); | |
256 | if (tmp->vm_flags & VM_DENYWRITE) | |
257 | atomic_dec(&inode->i_writecount); | |
258 | ||
259 | /* insert tmp into the share list, just after mpnt */ | |
260 | spin_lock(&file->f_mapping->i_mmap_lock); | |
261 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
262 | flush_dcache_mmap_lock(file->f_mapping); | |
263 | vma_prio_tree_add(tmp, mpnt); | |
264 | flush_dcache_mmap_unlock(file->f_mapping); | |
265 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
266 | } | |
267 | ||
268 | /* | |
7ee78232 | 269 | * Link in the new vma and copy the page table entries. |
1da177e4 | 270 | */ |
1da177e4 LT |
271 | *pprev = tmp; |
272 | pprev = &tmp->vm_next; | |
273 | ||
274 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
275 | rb_link = &tmp->vm_rb.rb_right; | |
276 | rb_parent = &tmp->vm_rb; | |
277 | ||
278 | mm->map_count++; | |
0b0db14c | 279 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
280 | |
281 | if (tmp->vm_ops && tmp->vm_ops->open) | |
282 | tmp->vm_ops->open(tmp); | |
283 | ||
284 | if (retval) | |
285 | goto out; | |
286 | } | |
287 | retval = 0; | |
1da177e4 | 288 | out: |
7ee78232 | 289 | up_write(&mm->mmap_sem); |
fd3e42fc | 290 | flush_tlb_mm(oldmm); |
1da177e4 LT |
291 | up_write(&oldmm->mmap_sem); |
292 | return retval; | |
293 | fail_nomem_policy: | |
294 | kmem_cache_free(vm_area_cachep, tmp); | |
295 | fail_nomem: | |
296 | retval = -ENOMEM; | |
297 | vm_unacct_memory(charge); | |
298 | goto out; | |
299 | } | |
300 | ||
301 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
302 | { | |
303 | mm->pgd = pgd_alloc(mm); | |
304 | if (unlikely(!mm->pgd)) | |
305 | return -ENOMEM; | |
306 | return 0; | |
307 | } | |
308 | ||
309 | static inline void mm_free_pgd(struct mm_struct * mm) | |
310 | { | |
311 | pgd_free(mm->pgd); | |
312 | } | |
313 | #else | |
314 | #define dup_mmap(mm, oldmm) (0) | |
315 | #define mm_alloc_pgd(mm) (0) | |
316 | #define mm_free_pgd(mm) | |
317 | #endif /* CONFIG_MMU */ | |
318 | ||
319 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); | |
320 | ||
321 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL)) | |
322 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
323 | ||
324 | #include <linux/init_task.h> | |
325 | ||
326 | static struct mm_struct * mm_init(struct mm_struct * mm) | |
327 | { | |
328 | atomic_set(&mm->mm_users, 1); | |
329 | atomic_set(&mm->mm_count, 1); | |
330 | init_rwsem(&mm->mmap_sem); | |
331 | INIT_LIST_HEAD(&mm->mmlist); | |
332 | mm->core_waiters = 0; | |
333 | mm->nr_ptes = 0; | |
4294621f | 334 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 335 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
336 | spin_lock_init(&mm->page_table_lock); |
337 | rwlock_init(&mm->ioctx_list_lock); | |
338 | mm->ioctx_list = NULL; | |
1da177e4 | 339 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 340 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
341 | |
342 | if (likely(!mm_alloc_pgd(mm))) { | |
343 | mm->def_flags = 0; | |
344 | return mm; | |
345 | } | |
346 | free_mm(mm); | |
347 | return NULL; | |
348 | } | |
349 | ||
350 | /* | |
351 | * Allocate and initialize an mm_struct. | |
352 | */ | |
353 | struct mm_struct * mm_alloc(void) | |
354 | { | |
355 | struct mm_struct * mm; | |
356 | ||
357 | mm = allocate_mm(); | |
358 | if (mm) { | |
359 | memset(mm, 0, sizeof(*mm)); | |
360 | mm = mm_init(mm); | |
361 | } | |
362 | return mm; | |
363 | } | |
364 | ||
365 | /* | |
366 | * Called when the last reference to the mm | |
367 | * is dropped: either by a lazy thread or by | |
368 | * mmput. Free the page directory and the mm. | |
369 | */ | |
370 | void fastcall __mmdrop(struct mm_struct *mm) | |
371 | { | |
372 | BUG_ON(mm == &init_mm); | |
373 | mm_free_pgd(mm); | |
374 | destroy_context(mm); | |
375 | free_mm(mm); | |
376 | } | |
377 | ||
378 | /* | |
379 | * Decrement the use count and release all resources for an mm. | |
380 | */ | |
381 | void mmput(struct mm_struct *mm) | |
382 | { | |
0ae26f1b AM |
383 | might_sleep(); |
384 | ||
1da177e4 LT |
385 | if (atomic_dec_and_test(&mm->mm_users)) { |
386 | exit_aio(mm); | |
387 | exit_mmap(mm); | |
388 | if (!list_empty(&mm->mmlist)) { | |
389 | spin_lock(&mmlist_lock); | |
390 | list_del(&mm->mmlist); | |
391 | spin_unlock(&mmlist_lock); | |
392 | } | |
393 | put_swap_token(mm); | |
394 | mmdrop(mm); | |
395 | } | |
396 | } | |
397 | EXPORT_SYMBOL_GPL(mmput); | |
398 | ||
399 | /** | |
400 | * get_task_mm - acquire a reference to the task's mm | |
401 | * | |
402 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning | |
403 | * this kernel workthread has transiently adopted a user mm with use_mm, | |
404 | * to do its AIO) is not set and if so returns a reference to it, after | |
405 | * bumping up the use count. User must release the mm via mmput() | |
406 | * after use. Typically used by /proc and ptrace. | |
407 | */ | |
408 | struct mm_struct *get_task_mm(struct task_struct *task) | |
409 | { | |
410 | struct mm_struct *mm; | |
411 | ||
412 | task_lock(task); | |
413 | mm = task->mm; | |
414 | if (mm) { | |
415 | if (task->flags & PF_BORROWED_MM) | |
416 | mm = NULL; | |
417 | else | |
418 | atomic_inc(&mm->mm_users); | |
419 | } | |
420 | task_unlock(task); | |
421 | return mm; | |
422 | } | |
423 | EXPORT_SYMBOL_GPL(get_task_mm); | |
424 | ||
425 | /* Please note the differences between mmput and mm_release. | |
426 | * mmput is called whenever we stop holding onto a mm_struct, | |
427 | * error success whatever. | |
428 | * | |
429 | * mm_release is called after a mm_struct has been removed | |
430 | * from the current process. | |
431 | * | |
432 | * This difference is important for error handling, when we | |
433 | * only half set up a mm_struct for a new process and need to restore | |
434 | * the old one. Because we mmput the new mm_struct before | |
435 | * restoring the old one. . . | |
436 | * Eric Biederman 10 January 1998 | |
437 | */ | |
438 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
439 | { | |
440 | struct completion *vfork_done = tsk->vfork_done; | |
441 | ||
442 | /* Get rid of any cached register state */ | |
443 | deactivate_mm(tsk, mm); | |
444 | ||
445 | /* notify parent sleeping on vfork() */ | |
446 | if (vfork_done) { | |
447 | tsk->vfork_done = NULL; | |
448 | complete(vfork_done); | |
449 | } | |
450 | if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) { | |
451 | u32 __user * tidptr = tsk->clear_child_tid; | |
452 | tsk->clear_child_tid = NULL; | |
453 | ||
454 | /* | |
455 | * We don't check the error code - if userspace has | |
456 | * not set up a proper pointer then tough luck. | |
457 | */ | |
458 | put_user(0, tidptr); | |
459 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
460 | } | |
461 | } | |
462 | ||
a0a7ec30 JD |
463 | /* |
464 | * Allocate a new mm structure and copy contents from the | |
465 | * mm structure of the passed in task structure. | |
466 | */ | |
467 | static struct mm_struct *dup_mm(struct task_struct *tsk) | |
468 | { | |
469 | struct mm_struct *mm, *oldmm = current->mm; | |
470 | int err; | |
471 | ||
472 | if (!oldmm) | |
473 | return NULL; | |
474 | ||
475 | mm = allocate_mm(); | |
476 | if (!mm) | |
477 | goto fail_nomem; | |
478 | ||
479 | memcpy(mm, oldmm, sizeof(*mm)); | |
480 | ||
481 | if (!mm_init(mm)) | |
482 | goto fail_nomem; | |
483 | ||
484 | if (init_new_context(tsk, mm)) | |
485 | goto fail_nocontext; | |
486 | ||
487 | err = dup_mmap(mm, oldmm); | |
488 | if (err) | |
489 | goto free_pt; | |
490 | ||
491 | mm->hiwater_rss = get_mm_rss(mm); | |
492 | mm->hiwater_vm = mm->total_vm; | |
493 | ||
494 | return mm; | |
495 | ||
496 | free_pt: | |
497 | mmput(mm); | |
498 | ||
499 | fail_nomem: | |
500 | return NULL; | |
501 | ||
502 | fail_nocontext: | |
503 | /* | |
504 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
505 | * because it calls destroy_context() | |
506 | */ | |
507 | mm_free_pgd(mm); | |
508 | free_mm(mm); | |
509 | return NULL; | |
510 | } | |
511 | ||
1da177e4 LT |
512 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
513 | { | |
514 | struct mm_struct * mm, *oldmm; | |
515 | int retval; | |
516 | ||
517 | tsk->min_flt = tsk->maj_flt = 0; | |
518 | tsk->nvcsw = tsk->nivcsw = 0; | |
519 | ||
520 | tsk->mm = NULL; | |
521 | tsk->active_mm = NULL; | |
522 | ||
523 | /* | |
524 | * Are we cloning a kernel thread? | |
525 | * | |
526 | * We need to steal a active VM for that.. | |
527 | */ | |
528 | oldmm = current->mm; | |
529 | if (!oldmm) | |
530 | return 0; | |
531 | ||
532 | if (clone_flags & CLONE_VM) { | |
533 | atomic_inc(&oldmm->mm_users); | |
534 | mm = oldmm; | |
1da177e4 LT |
535 | goto good_mm; |
536 | } | |
537 | ||
538 | retval = -ENOMEM; | |
a0a7ec30 | 539 | mm = dup_mm(tsk); |
1da177e4 LT |
540 | if (!mm) |
541 | goto fail_nomem; | |
542 | ||
1da177e4 LT |
543 | good_mm: |
544 | tsk->mm = mm; | |
545 | tsk->active_mm = mm; | |
546 | return 0; | |
547 | ||
1da177e4 LT |
548 | fail_nomem: |
549 | return retval; | |
1da177e4 LT |
550 | } |
551 | ||
552 | static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old) | |
553 | { | |
554 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
555 | /* We don't need to lock fs - think why ;-) */ | |
556 | if (fs) { | |
557 | atomic_set(&fs->count, 1); | |
558 | rwlock_init(&fs->lock); | |
559 | fs->umask = old->umask; | |
560 | read_lock(&old->lock); | |
561 | fs->rootmnt = mntget(old->rootmnt); | |
562 | fs->root = dget(old->root); | |
563 | fs->pwdmnt = mntget(old->pwdmnt); | |
564 | fs->pwd = dget(old->pwd); | |
565 | if (old->altroot) { | |
566 | fs->altrootmnt = mntget(old->altrootmnt); | |
567 | fs->altroot = dget(old->altroot); | |
568 | } else { | |
569 | fs->altrootmnt = NULL; | |
570 | fs->altroot = NULL; | |
571 | } | |
572 | read_unlock(&old->lock); | |
573 | } | |
574 | return fs; | |
575 | } | |
576 | ||
577 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
578 | { | |
579 | return __copy_fs_struct(old); | |
580 | } | |
581 | ||
582 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
583 | ||
584 | static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk) | |
585 | { | |
586 | if (clone_flags & CLONE_FS) { | |
587 | atomic_inc(¤t->fs->count); | |
588 | return 0; | |
589 | } | |
590 | tsk->fs = __copy_fs_struct(current->fs); | |
591 | if (!tsk->fs) | |
592 | return -ENOMEM; | |
593 | return 0; | |
594 | } | |
595 | ||
ab2af1f5 | 596 | static int count_open_files(struct fdtable *fdt) |
1da177e4 | 597 | { |
ab2af1f5 | 598 | int size = fdt->max_fdset; |
1da177e4 LT |
599 | int i; |
600 | ||
601 | /* Find the last open fd */ | |
602 | for (i = size/(8*sizeof(long)); i > 0; ) { | |
badf1662 | 603 | if (fdt->open_fds->fds_bits[--i]) |
1da177e4 LT |
604 | break; |
605 | } | |
606 | i = (i+1) * 8 * sizeof(long); | |
607 | return i; | |
608 | } | |
609 | ||
badf1662 DS |
610 | static struct files_struct *alloc_files(void) |
611 | { | |
612 | struct files_struct *newf; | |
613 | struct fdtable *fdt; | |
614 | ||
615 | newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL); | |
616 | if (!newf) | |
617 | goto out; | |
618 | ||
619 | atomic_set(&newf->count, 1); | |
620 | ||
621 | spin_lock_init(&newf->file_lock); | |
0c9e63fd | 622 | newf->next_fd = 0; |
ab2af1f5 | 623 | fdt = &newf->fdtab; |
badf1662 | 624 | fdt->max_fds = NR_OPEN_DEFAULT; |
0c9e63fd ED |
625 | fdt->max_fdset = EMBEDDED_FD_SET_SIZE; |
626 | fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init; | |
627 | fdt->open_fds = (fd_set *)&newf->open_fds_init; | |
badf1662 | 628 | fdt->fd = &newf->fd_array[0]; |
ab2af1f5 DS |
629 | INIT_RCU_HEAD(&fdt->rcu); |
630 | fdt->free_files = NULL; | |
631 | fdt->next = NULL; | |
632 | rcu_assign_pointer(newf->fdt, fdt); | |
badf1662 DS |
633 | out: |
634 | return newf; | |
635 | } | |
636 | ||
a016f338 JD |
637 | /* |
638 | * Allocate a new files structure and copy contents from the | |
639 | * passed in files structure. | |
6e667260 | 640 | * errorp will be valid only when the returned files_struct is NULL. |
a016f338 JD |
641 | */ |
642 | static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) | |
1da177e4 | 643 | { |
a016f338 | 644 | struct files_struct *newf; |
1da177e4 | 645 | struct file **old_fds, **new_fds; |
a016f338 | 646 | int open_files, size, i, expand; |
badf1662 | 647 | struct fdtable *old_fdt, *new_fdt; |
1da177e4 | 648 | |
6e667260 | 649 | *errorp = -ENOMEM; |
badf1662 DS |
650 | newf = alloc_files(); |
651 | if (!newf) | |
1da177e4 LT |
652 | goto out; |
653 | ||
1da177e4 | 654 | spin_lock(&oldf->file_lock); |
badf1662 DS |
655 | old_fdt = files_fdtable(oldf); |
656 | new_fdt = files_fdtable(newf); | |
657 | size = old_fdt->max_fdset; | |
ab2af1f5 | 658 | open_files = count_open_files(old_fdt); |
1da177e4 LT |
659 | expand = 0; |
660 | ||
661 | /* | |
662 | * Check whether we need to allocate a larger fd array or fd set. | |
663 | * Note: we're not a clone task, so the open count won't change. | |
664 | */ | |
badf1662 DS |
665 | if (open_files > new_fdt->max_fdset) { |
666 | new_fdt->max_fdset = 0; | |
1da177e4 LT |
667 | expand = 1; |
668 | } | |
badf1662 DS |
669 | if (open_files > new_fdt->max_fds) { |
670 | new_fdt->max_fds = 0; | |
1da177e4 LT |
671 | expand = 1; |
672 | } | |
673 | ||
674 | /* if the old fdset gets grown now, we'll only copy up to "size" fds */ | |
675 | if (expand) { | |
676 | spin_unlock(&oldf->file_lock); | |
677 | spin_lock(&newf->file_lock); | |
a016f338 | 678 | *errorp = expand_files(newf, open_files-1); |
1da177e4 | 679 | spin_unlock(&newf->file_lock); |
a016f338 | 680 | if (*errorp < 0) |
1da177e4 | 681 | goto out_release; |
ab2af1f5 DS |
682 | new_fdt = files_fdtable(newf); |
683 | /* | |
684 | * Reacquire the oldf lock and a pointer to its fd table | |
685 | * who knows it may have a new bigger fd table. We need | |
686 | * the latest pointer. | |
687 | */ | |
1da177e4 | 688 | spin_lock(&oldf->file_lock); |
ab2af1f5 | 689 | old_fdt = files_fdtable(oldf); |
1da177e4 LT |
690 | } |
691 | ||
badf1662 DS |
692 | old_fds = old_fdt->fd; |
693 | new_fds = new_fdt->fd; | |
1da177e4 | 694 | |
badf1662 DS |
695 | memcpy(new_fdt->open_fds->fds_bits, old_fdt->open_fds->fds_bits, open_files/8); |
696 | memcpy(new_fdt->close_on_exec->fds_bits, old_fdt->close_on_exec->fds_bits, open_files/8); | |
1da177e4 LT |
697 | |
698 | for (i = open_files; i != 0; i--) { | |
699 | struct file *f = *old_fds++; | |
700 | if (f) { | |
701 | get_file(f); | |
702 | } else { | |
703 | /* | |
704 | * The fd may be claimed in the fd bitmap but not yet | |
705 | * instantiated in the files array if a sibling thread | |
706 | * is partway through open(). So make sure that this | |
707 | * fd is available to the new process. | |
708 | */ | |
badf1662 | 709 | FD_CLR(open_files - i, new_fdt->open_fds); |
1da177e4 | 710 | } |
ab2af1f5 | 711 | rcu_assign_pointer(*new_fds++, f); |
1da177e4 LT |
712 | } |
713 | spin_unlock(&oldf->file_lock); | |
714 | ||
715 | /* compute the remainder to be cleared */ | |
badf1662 | 716 | size = (new_fdt->max_fds - open_files) * sizeof(struct file *); |
1da177e4 LT |
717 | |
718 | /* This is long word aligned thus could use a optimized version */ | |
719 | memset(new_fds, 0, size); | |
720 | ||
badf1662 DS |
721 | if (new_fdt->max_fdset > open_files) { |
722 | int left = (new_fdt->max_fdset-open_files)/8; | |
1da177e4 LT |
723 | int start = open_files / (8 * sizeof(unsigned long)); |
724 | ||
badf1662 DS |
725 | memset(&new_fdt->open_fds->fds_bits[start], 0, left); |
726 | memset(&new_fdt->close_on_exec->fds_bits[start], 0, left); | |
1da177e4 LT |
727 | } |
728 | ||
1da177e4 | 729 | out: |
a016f338 | 730 | return newf; |
1da177e4 LT |
731 | |
732 | out_release: | |
badf1662 DS |
733 | free_fdset (new_fdt->close_on_exec, new_fdt->max_fdset); |
734 | free_fdset (new_fdt->open_fds, new_fdt->max_fdset); | |
735 | free_fd_array(new_fdt->fd, new_fdt->max_fds); | |
1da177e4 | 736 | kmem_cache_free(files_cachep, newf); |
42862298 | 737 | return NULL; |
1da177e4 LT |
738 | } |
739 | ||
a016f338 JD |
740 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
741 | { | |
742 | struct files_struct *oldf, *newf; | |
743 | int error = 0; | |
744 | ||
745 | /* | |
746 | * A background process may not have any files ... | |
747 | */ | |
748 | oldf = current->files; | |
749 | if (!oldf) | |
750 | goto out; | |
751 | ||
752 | if (clone_flags & CLONE_FILES) { | |
753 | atomic_inc(&oldf->count); | |
754 | goto out; | |
755 | } | |
756 | ||
757 | /* | |
758 | * Note: we may be using current for both targets (See exec.c) | |
759 | * This works because we cache current->files (old) as oldf. Don't | |
760 | * break this. | |
761 | */ | |
762 | tsk->files = NULL; | |
a016f338 JD |
763 | newf = dup_fd(oldf, &error); |
764 | if (!newf) | |
765 | goto out; | |
766 | ||
767 | tsk->files = newf; | |
768 | error = 0; | |
769 | out: | |
770 | return error; | |
771 | } | |
772 | ||
1da177e4 LT |
773 | /* |
774 | * Helper to unshare the files of the current task. | |
775 | * We don't want to expose copy_files internals to | |
776 | * the exec layer of the kernel. | |
777 | */ | |
778 | ||
779 | int unshare_files(void) | |
780 | { | |
781 | struct files_struct *files = current->files; | |
782 | int rc; | |
783 | ||
910dea7f | 784 | BUG_ON(!files); |
1da177e4 LT |
785 | |
786 | /* This can race but the race causes us to copy when we don't | |
787 | need to and drop the copy */ | |
788 | if(atomic_read(&files->count) == 1) | |
789 | { | |
790 | atomic_inc(&files->count); | |
791 | return 0; | |
792 | } | |
793 | rc = copy_files(0, current); | |
794 | if(rc) | |
795 | current->files = files; | |
796 | return rc; | |
797 | } | |
798 | ||
799 | EXPORT_SYMBOL(unshare_files); | |
800 | ||
801 | static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk) | |
802 | { | |
803 | struct sighand_struct *sig; | |
804 | ||
805 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
806 | atomic_inc(¤t->sighand->count); | |
807 | return 0; | |
808 | } | |
809 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 810 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
811 | if (!sig) |
812 | return -ENOMEM; | |
1da177e4 LT |
813 | atomic_set(&sig->count, 1); |
814 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
815 | return 0; | |
816 | } | |
817 | ||
a7e5328a | 818 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 819 | { |
c81addc9 ON |
820 | if (atomic_dec_and_test(&sighand->count)) |
821 | kmem_cache_free(sighand_cachep, sighand); | |
822 | } | |
823 | ||
1da177e4 LT |
824 | static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk) |
825 | { | |
826 | struct signal_struct *sig; | |
827 | int ret; | |
828 | ||
829 | if (clone_flags & CLONE_THREAD) { | |
830 | atomic_inc(¤t->signal->count); | |
831 | atomic_inc(¤t->signal->live); | |
ad4ecbcb | 832 | taskstats_tgid_alloc(current->signal); |
1da177e4 LT |
833 | return 0; |
834 | } | |
835 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
836 | tsk->signal = sig; | |
837 | if (!sig) | |
838 | return -ENOMEM; | |
839 | ||
840 | ret = copy_thread_group_keys(tsk); | |
841 | if (ret < 0) { | |
842 | kmem_cache_free(signal_cachep, sig); | |
843 | return ret; | |
844 | } | |
845 | ||
846 | atomic_set(&sig->count, 1); | |
847 | atomic_set(&sig->live, 1); | |
848 | init_waitqueue_head(&sig->wait_chldexit); | |
849 | sig->flags = 0; | |
850 | sig->group_exit_code = 0; | |
851 | sig->group_exit_task = NULL; | |
852 | sig->group_stop_count = 0; | |
853 | sig->curr_target = NULL; | |
854 | init_sigpending(&sig->shared_pending); | |
855 | INIT_LIST_HEAD(&sig->posix_timers); | |
856 | ||
7978672c | 857 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL); |
2ff678b8 | 858 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 859 | sig->real_timer.function = it_real_fn; |
05cfb614 | 860 | sig->tsk = tsk; |
1da177e4 LT |
861 | |
862 | sig->it_virt_expires = cputime_zero; | |
863 | sig->it_virt_incr = cputime_zero; | |
864 | sig->it_prof_expires = cputime_zero; | |
865 | sig->it_prof_incr = cputime_zero; | |
866 | ||
1da177e4 LT |
867 | sig->leader = 0; /* session leadership doesn't inherit */ |
868 | sig->tty_old_pgrp = 0; | |
869 | ||
870 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
871 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; | |
872 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
873 | sig->sched_time = 0; | |
874 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
875 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
876 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
ad4ecbcb | 877 | taskstats_tgid_init(sig); |
1da177e4 LT |
878 | |
879 | task_lock(current->group_leader); | |
880 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
881 | task_unlock(current->group_leader); | |
882 | ||
883 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
884 | /* | |
885 | * New sole thread in the process gets an expiry time | |
886 | * of the whole CPU time limit. | |
887 | */ | |
888 | tsk->it_prof_expires = | |
889 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
890 | } | |
0e464814 | 891 | acct_init_pacct(&sig->pacct); |
1da177e4 LT |
892 | |
893 | return 0; | |
894 | } | |
895 | ||
6b3934ef ON |
896 | void __cleanup_signal(struct signal_struct *sig) |
897 | { | |
898 | exit_thread_group_keys(sig); | |
ad4ecbcb | 899 | taskstats_tgid_free(sig); |
6b3934ef ON |
900 | kmem_cache_free(signal_cachep, sig); |
901 | } | |
902 | ||
903 | static inline void cleanup_signal(struct task_struct *tsk) | |
904 | { | |
905 | struct signal_struct *sig = tsk->signal; | |
906 | ||
907 | atomic_dec(&sig->live); | |
908 | ||
909 | if (atomic_dec_and_test(&sig->count)) | |
910 | __cleanup_signal(sig); | |
911 | } | |
912 | ||
1da177e4 LT |
913 | static inline void copy_flags(unsigned long clone_flags, struct task_struct *p) |
914 | { | |
915 | unsigned long new_flags = p->flags; | |
916 | ||
d1209d04 | 917 | new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE); |
1da177e4 LT |
918 | new_flags |= PF_FORKNOEXEC; |
919 | if (!(clone_flags & CLONE_PTRACE)) | |
920 | p->ptrace = 0; | |
921 | p->flags = new_flags; | |
922 | } | |
923 | ||
924 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
925 | { | |
926 | current->clear_child_tid = tidptr; | |
927 | ||
928 | return current->pid; | |
929 | } | |
930 | ||
23f78d4a IM |
931 | static inline void rt_mutex_init_task(struct task_struct *p) |
932 | { | |
933 | #ifdef CONFIG_RT_MUTEXES | |
934 | spin_lock_init(&p->pi_lock); | |
935 | plist_head_init(&p->pi_waiters, &p->pi_lock); | |
936 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
937 | #endif |
938 | } | |
939 | ||
1da177e4 LT |
940 | /* |
941 | * This creates a new process as a copy of the old one, | |
942 | * but does not actually start it yet. | |
943 | * | |
944 | * It copies the registers, and all the appropriate | |
945 | * parts of the process environment (as per the clone | |
946 | * flags). The actual kick-off is left to the caller. | |
947 | */ | |
36c8b586 IM |
948 | static struct task_struct *copy_process(unsigned long clone_flags, |
949 | unsigned long stack_start, | |
950 | struct pt_regs *regs, | |
951 | unsigned long stack_size, | |
952 | int __user *parent_tidptr, | |
953 | int __user *child_tidptr, | |
954 | int pid) | |
1da177e4 LT |
955 | { |
956 | int retval; | |
957 | struct task_struct *p = NULL; | |
958 | ||
959 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
960 | return ERR_PTR(-EINVAL); | |
961 | ||
962 | /* | |
963 | * Thread groups must share signals as well, and detached threads | |
964 | * can only be started up within the thread group. | |
965 | */ | |
966 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
967 | return ERR_PTR(-EINVAL); | |
968 | ||
969 | /* | |
970 | * Shared signal handlers imply shared VM. By way of the above, | |
971 | * thread groups also imply shared VM. Blocking this case allows | |
972 | * for various simplifications in other code. | |
973 | */ | |
974 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
975 | return ERR_PTR(-EINVAL); | |
976 | ||
977 | retval = security_task_create(clone_flags); | |
978 | if (retval) | |
979 | goto fork_out; | |
980 | ||
981 | retval = -ENOMEM; | |
982 | p = dup_task_struct(current); | |
983 | if (!p) | |
984 | goto fork_out; | |
985 | ||
de30a2b3 IM |
986 | #ifdef CONFIG_TRACE_IRQFLAGS |
987 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); | |
988 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
989 | #endif | |
1da177e4 LT |
990 | retval = -EAGAIN; |
991 | if (atomic_read(&p->user->processes) >= | |
992 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
993 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
994 | p->user != &root_user) | |
995 | goto bad_fork_free; | |
996 | } | |
997 | ||
998 | atomic_inc(&p->user->__count); | |
999 | atomic_inc(&p->user->processes); | |
1000 | get_group_info(p->group_info); | |
1001 | ||
1002 | /* | |
1003 | * If multiple threads are within copy_process(), then this check | |
1004 | * triggers too late. This doesn't hurt, the check is only there | |
1005 | * to stop root fork bombs. | |
1006 | */ | |
1007 | if (nr_threads >= max_threads) | |
1008 | goto bad_fork_cleanup_count; | |
1009 | ||
a1261f54 | 1010 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1011 | goto bad_fork_cleanup_count; |
1012 | ||
1013 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
1014 | goto bad_fork_cleanup_put_domain; | |
1015 | ||
1016 | p->did_exec = 0; | |
ca74e92b | 1017 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 LT |
1018 | copy_flags(clone_flags, p); |
1019 | p->pid = pid; | |
1020 | retval = -EFAULT; | |
1021 | if (clone_flags & CLONE_PARENT_SETTID) | |
1022 | if (put_user(p->pid, parent_tidptr)) | |
35df17c5 | 1023 | goto bad_fork_cleanup_delays_binfmt; |
1da177e4 | 1024 | |
1da177e4 LT |
1025 | INIT_LIST_HEAD(&p->children); |
1026 | INIT_LIST_HEAD(&p->sibling); | |
1027 | p->vfork_done = NULL; | |
1028 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
1029 | |
1030 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
1031 | init_sigpending(&p->pending); | |
1032 | ||
1033 | p->utime = cputime_zero; | |
1034 | p->stime = cputime_zero; | |
1035 | p->sched_time = 0; | |
1036 | p->rchar = 0; /* I/O counter: bytes read */ | |
1037 | p->wchar = 0; /* I/O counter: bytes written */ | |
1038 | p->syscr = 0; /* I/O counter: read syscalls */ | |
1039 | p->syscw = 0; /* I/O counter: write syscalls */ | |
1040 | acct_clear_integrals(p); | |
1041 | ||
1042 | p->it_virt_expires = cputime_zero; | |
1043 | p->it_prof_expires = cputime_zero; | |
1044 | p->it_sched_expires = 0; | |
1045 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1046 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1047 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1048 | ||
1049 | p->lock_depth = -1; /* -1 = no lock */ | |
1050 | do_posix_clock_monotonic_gettime(&p->start_time); | |
1051 | p->security = NULL; | |
1052 | p->io_context = NULL; | |
1053 | p->io_wait = NULL; | |
1054 | p->audit_context = NULL; | |
b4b26418 | 1055 | cpuset_fork(p); |
1da177e4 LT |
1056 | #ifdef CONFIG_NUMA |
1057 | p->mempolicy = mpol_copy(p->mempolicy); | |
1058 | if (IS_ERR(p->mempolicy)) { | |
1059 | retval = PTR_ERR(p->mempolicy); | |
1060 | p->mempolicy = NULL; | |
b4b26418 | 1061 | goto bad_fork_cleanup_cpuset; |
1da177e4 | 1062 | } |
c61afb18 | 1063 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1064 | #endif |
de30a2b3 IM |
1065 | #ifdef CONFIG_TRACE_IRQFLAGS |
1066 | p->irq_events = 0; | |
b36e4758 RK |
1067 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1068 | p->hardirqs_enabled = 1; | |
1069 | #else | |
de30a2b3 | 1070 | p->hardirqs_enabled = 0; |
b36e4758 | 1071 | #endif |
de30a2b3 IM |
1072 | p->hardirq_enable_ip = 0; |
1073 | p->hardirq_enable_event = 0; | |
1074 | p->hardirq_disable_ip = _THIS_IP_; | |
1075 | p->hardirq_disable_event = 0; | |
1076 | p->softirqs_enabled = 1; | |
1077 | p->softirq_enable_ip = _THIS_IP_; | |
1078 | p->softirq_enable_event = 0; | |
1079 | p->softirq_disable_ip = 0; | |
1080 | p->softirq_disable_event = 0; | |
1081 | p->hardirq_context = 0; | |
1082 | p->softirq_context = 0; | |
1083 | #endif | |
fbb9ce95 IM |
1084 | #ifdef CONFIG_LOCKDEP |
1085 | p->lockdep_depth = 0; /* no locks held yet */ | |
1086 | p->curr_chain_key = 0; | |
1087 | p->lockdep_recursion = 0; | |
1088 | #endif | |
1da177e4 | 1089 | |
23f78d4a IM |
1090 | rt_mutex_init_task(p); |
1091 | ||
408894ee IM |
1092 | #ifdef CONFIG_DEBUG_MUTEXES |
1093 | p->blocked_on = NULL; /* not blocked yet */ | |
1094 | #endif | |
1095 | ||
1da177e4 LT |
1096 | p->tgid = p->pid; |
1097 | if (clone_flags & CLONE_THREAD) | |
1098 | p->tgid = current->tgid; | |
1099 | ||
1100 | if ((retval = security_task_alloc(p))) | |
1101 | goto bad_fork_cleanup_policy; | |
1102 | if ((retval = audit_alloc(p))) | |
1103 | goto bad_fork_cleanup_security; | |
1104 | /* copy all the process information */ | |
1105 | if ((retval = copy_semundo(clone_flags, p))) | |
1106 | goto bad_fork_cleanup_audit; | |
1107 | if ((retval = copy_files(clone_flags, p))) | |
1108 | goto bad_fork_cleanup_semundo; | |
1109 | if ((retval = copy_fs(clone_flags, p))) | |
1110 | goto bad_fork_cleanup_files; | |
1111 | if ((retval = copy_sighand(clone_flags, p))) | |
1112 | goto bad_fork_cleanup_fs; | |
1113 | if ((retval = copy_signal(clone_flags, p))) | |
1114 | goto bad_fork_cleanup_sighand; | |
1115 | if ((retval = copy_mm(clone_flags, p))) | |
1116 | goto bad_fork_cleanup_signal; | |
1117 | if ((retval = copy_keys(clone_flags, p))) | |
1118 | goto bad_fork_cleanup_mm; | |
1119 | if ((retval = copy_namespace(clone_flags, p))) | |
1120 | goto bad_fork_cleanup_keys; | |
1121 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); | |
1122 | if (retval) | |
1123 | goto bad_fork_cleanup_namespace; | |
1124 | ||
1125 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; | |
1126 | /* | |
1127 | * Clear TID on mm_release()? | |
1128 | */ | |
1129 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
8f17d3a5 IM |
1130 | p->robust_list = NULL; |
1131 | #ifdef CONFIG_COMPAT | |
1132 | p->compat_robust_list = NULL; | |
1133 | #endif | |
c87e2837 IM |
1134 | INIT_LIST_HEAD(&p->pi_state_list); |
1135 | p->pi_state_cache = NULL; | |
1136 | ||
f9a3879a GM |
1137 | /* |
1138 | * sigaltstack should be cleared when sharing the same VM | |
1139 | */ | |
1140 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1141 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1142 | ||
1da177e4 LT |
1143 | /* |
1144 | * Syscall tracing should be turned off in the child regardless | |
1145 | * of CLONE_PTRACE. | |
1146 | */ | |
1147 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1148 | #ifdef TIF_SYSCALL_EMU |
1149 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1150 | #endif | |
1da177e4 LT |
1151 | |
1152 | /* Our parent execution domain becomes current domain | |
1153 | These must match for thread signalling to apply */ | |
1da177e4 LT |
1154 | p->parent_exec_id = p->self_exec_id; |
1155 | ||
1156 | /* ok, now we should be set up.. */ | |
1157 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1158 | p->pdeath_signal = 0; | |
1159 | p->exit_state = 0; | |
1160 | ||
1da177e4 LT |
1161 | /* |
1162 | * Ok, make it visible to the rest of the system. | |
1163 | * We dont wake it up yet. | |
1164 | */ | |
1165 | p->group_leader = p; | |
47e65328 | 1166 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 LT |
1167 | INIT_LIST_HEAD(&p->ptrace_children); |
1168 | INIT_LIST_HEAD(&p->ptrace_list); | |
1169 | ||
476d139c NP |
1170 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1171 | sched_fork(p, clone_flags); | |
1172 | ||
1da177e4 LT |
1173 | /* Need tasklist lock for parent etc handling! */ |
1174 | write_lock_irq(&tasklist_lock); | |
1175 | ||
5b160f5e ON |
1176 | /* for sys_ioprio_set(IOPRIO_WHO_PGRP) */ |
1177 | p->ioprio = current->ioprio; | |
1178 | ||
1da177e4 | 1179 | /* |
476d139c NP |
1180 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1181 | * not be changed, nor will its assigned CPU. | |
1182 | * | |
1183 | * The cpus_allowed mask of the parent may have changed after it was | |
1184 | * copied first time - so re-copy it here, then check the child's CPU | |
1185 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1186 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1187 | */ |
1188 | p->cpus_allowed = current->cpus_allowed; | |
26ff6ad9 SV |
1189 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1190 | !cpu_online(task_cpu(p)))) | |
476d139c | 1191 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1192 | |
1da177e4 LT |
1193 | /* CLONE_PARENT re-uses the old parent */ |
1194 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1195 | p->real_parent = current->real_parent; | |
1196 | else | |
1197 | p->real_parent = current; | |
1198 | p->parent = p->real_parent; | |
1199 | ||
3f17da69 | 1200 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1201 | |
1202 | /* | |
1203 | * Process group and session signals need to be delivered to just the | |
1204 | * parent before the fork or both the parent and the child after the | |
1205 | * fork. Restart if a signal comes in before we add the new process to | |
1206 | * it's process group. | |
1207 | * A fatal signal pending means that current will exit, so the new | |
1208 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1209 | */ | |
1210 | recalc_sigpending(); | |
1211 | if (signal_pending(current)) { | |
1212 | spin_unlock(¤t->sighand->siglock); | |
1213 | write_unlock_irq(&tasklist_lock); | |
1214 | retval = -ERESTARTNOINTR; | |
1215 | goto bad_fork_cleanup_namespace; | |
1216 | } | |
1217 | ||
1da177e4 | 1218 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1219 | p->group_leader = current->group_leader; |
47e65328 | 1220 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1221 | |
1da177e4 LT |
1222 | if (!cputime_eq(current->signal->it_virt_expires, |
1223 | cputime_zero) || | |
1224 | !cputime_eq(current->signal->it_prof_expires, | |
1225 | cputime_zero) || | |
1226 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1227 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1228 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1229 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1230 | /* | |
1231 | * Have child wake up on its first tick to check | |
1232 | * for process CPU timers. | |
1233 | */ | |
1234 | p->it_prof_expires = jiffies_to_cputime(1); | |
1235 | } | |
1da177e4 LT |
1236 | } |
1237 | ||
73b9ebfe ON |
1238 | if (likely(p->pid)) { |
1239 | add_parent(p); | |
1240 | if (unlikely(p->ptrace & PT_PTRACED)) | |
1241 | __ptrace_link(p, current->parent); | |
1242 | ||
1243 | if (thread_group_leader(p)) { | |
1244 | p->signal->tty = current->signal->tty; | |
1245 | p->signal->pgrp = process_group(current); | |
1246 | p->signal->session = current->signal->session; | |
1247 | attach_pid(p, PIDTYPE_PGID, process_group(p)); | |
1248 | attach_pid(p, PIDTYPE_SID, p->signal->session); | |
1249 | ||
5e85d4ab | 1250 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1251 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1252 | } |
73b9ebfe ON |
1253 | attach_pid(p, PIDTYPE_PID, p->pid); |
1254 | nr_threads++; | |
1da177e4 LT |
1255 | } |
1256 | ||
1da177e4 | 1257 | total_forks++; |
3f17da69 | 1258 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1259 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1260 | proc_fork_connector(p); |
1da177e4 LT |
1261 | return p; |
1262 | ||
1263 | bad_fork_cleanup_namespace: | |
1264 | exit_namespace(p); | |
1265 | bad_fork_cleanup_keys: | |
1266 | exit_keys(p); | |
1267 | bad_fork_cleanup_mm: | |
1268 | if (p->mm) | |
1269 | mmput(p->mm); | |
1270 | bad_fork_cleanup_signal: | |
6b3934ef | 1271 | cleanup_signal(p); |
1da177e4 | 1272 | bad_fork_cleanup_sighand: |
a7e5328a | 1273 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1274 | bad_fork_cleanup_fs: |
1275 | exit_fs(p); /* blocking */ | |
1276 | bad_fork_cleanup_files: | |
1277 | exit_files(p); /* blocking */ | |
1278 | bad_fork_cleanup_semundo: | |
1279 | exit_sem(p); | |
1280 | bad_fork_cleanup_audit: | |
1281 | audit_free(p); | |
1282 | bad_fork_cleanup_security: | |
1283 | security_task_free(p); | |
1284 | bad_fork_cleanup_policy: | |
1285 | #ifdef CONFIG_NUMA | |
1286 | mpol_free(p->mempolicy); | |
b4b26418 | 1287 | bad_fork_cleanup_cpuset: |
1da177e4 | 1288 | #endif |
b4b26418 | 1289 | cpuset_exit(p); |
35df17c5 SN |
1290 | bad_fork_cleanup_delays_binfmt: |
1291 | delayacct_tsk_free(p); | |
1da177e4 LT |
1292 | if (p->binfmt) |
1293 | module_put(p->binfmt->module); | |
1294 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1295 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1296 | bad_fork_cleanup_count: |
1297 | put_group_info(p->group_info); | |
1298 | atomic_dec(&p->user->processes); | |
1299 | free_uid(p->user); | |
1300 | bad_fork_free: | |
1301 | free_task(p); | |
fe7d37d1 ON |
1302 | fork_out: |
1303 | return ERR_PTR(retval); | |
1da177e4 LT |
1304 | } |
1305 | ||
1306 | struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs) | |
1307 | { | |
1308 | memset(regs, 0, sizeof(struct pt_regs)); | |
1309 | return regs; | |
1310 | } | |
1311 | ||
36c8b586 | 1312 | struct task_struct * __devinit fork_idle(int cpu) |
1da177e4 | 1313 | { |
36c8b586 | 1314 | struct task_struct *task; |
1da177e4 LT |
1315 | struct pt_regs regs; |
1316 | ||
1317 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0); | |
1318 | if (!task) | |
1319 | return ERR_PTR(-ENOMEM); | |
1320 | init_idle(task, cpu); | |
73b9ebfe | 1321 | |
1da177e4 LT |
1322 | return task; |
1323 | } | |
1324 | ||
1325 | static inline int fork_traceflag (unsigned clone_flags) | |
1326 | { | |
1327 | if (clone_flags & CLONE_UNTRACED) | |
1328 | return 0; | |
1329 | else if (clone_flags & CLONE_VFORK) { | |
1330 | if (current->ptrace & PT_TRACE_VFORK) | |
1331 | return PTRACE_EVENT_VFORK; | |
1332 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1333 | if (current->ptrace & PT_TRACE_CLONE) | |
1334 | return PTRACE_EVENT_CLONE; | |
1335 | } else if (current->ptrace & PT_TRACE_FORK) | |
1336 | return PTRACE_EVENT_FORK; | |
1337 | ||
1338 | return 0; | |
1339 | } | |
1340 | ||
1341 | /* | |
1342 | * Ok, this is the main fork-routine. | |
1343 | * | |
1344 | * It copies the process, and if successful kick-starts | |
1345 | * it and waits for it to finish using the VM if required. | |
1346 | */ | |
1347 | long do_fork(unsigned long clone_flags, | |
1348 | unsigned long stack_start, | |
1349 | struct pt_regs *regs, | |
1350 | unsigned long stack_size, | |
1351 | int __user *parent_tidptr, | |
1352 | int __user *child_tidptr) | |
1353 | { | |
1354 | struct task_struct *p; | |
1355 | int trace = 0; | |
92476d7f EB |
1356 | struct pid *pid = alloc_pid(); |
1357 | long nr; | |
1da177e4 | 1358 | |
92476d7f | 1359 | if (!pid) |
1da177e4 | 1360 | return -EAGAIN; |
92476d7f | 1361 | nr = pid->nr; |
1da177e4 LT |
1362 | if (unlikely(current->ptrace)) { |
1363 | trace = fork_traceflag (clone_flags); | |
1364 | if (trace) | |
1365 | clone_flags |= CLONE_PTRACE; | |
1366 | } | |
1367 | ||
92476d7f | 1368 | p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, nr); |
1da177e4 LT |
1369 | /* |
1370 | * Do this prior waking up the new thread - the thread pointer | |
1371 | * might get invalid after that point, if the thread exits quickly. | |
1372 | */ | |
1373 | if (!IS_ERR(p)) { | |
1374 | struct completion vfork; | |
1375 | ||
1376 | if (clone_flags & CLONE_VFORK) { | |
1377 | p->vfork_done = &vfork; | |
1378 | init_completion(&vfork); | |
1379 | } | |
1380 | ||
1381 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1382 | /* | |
1383 | * We'll start up with an immediate SIGSTOP. | |
1384 | */ | |
1385 | sigaddset(&p->pending.signal, SIGSTOP); | |
1386 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1387 | } | |
1388 | ||
1389 | if (!(clone_flags & CLONE_STOPPED)) | |
1390 | wake_up_new_task(p, clone_flags); | |
1391 | else | |
1392 | p->state = TASK_STOPPED; | |
1393 | ||
1394 | if (unlikely (trace)) { | |
92476d7f | 1395 | current->ptrace_message = nr; |
1da177e4 LT |
1396 | ptrace_notify ((trace << 8) | SIGTRAP); |
1397 | } | |
1398 | ||
1399 | if (clone_flags & CLONE_VFORK) { | |
1400 | wait_for_completion(&vfork); | |
9f59ce5d CE |
1401 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) { |
1402 | current->ptrace_message = nr; | |
1da177e4 | 1403 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); |
9f59ce5d | 1404 | } |
1da177e4 LT |
1405 | } |
1406 | } else { | |
92476d7f EB |
1407 | free_pid(pid); |
1408 | nr = PTR_ERR(p); | |
1da177e4 | 1409 | } |
92476d7f | 1410 | return nr; |
1da177e4 LT |
1411 | } |
1412 | ||
5fd63b30 RT |
1413 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1414 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1415 | #endif | |
1416 | ||
aa1757f9 ON |
1417 | static void sighand_ctor(void *data, kmem_cache_t *cachep, unsigned long flags) |
1418 | { | |
1419 | struct sighand_struct *sighand = data; | |
1420 | ||
1421 | if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == | |
1422 | SLAB_CTOR_CONSTRUCTOR) | |
1423 | spin_lock_init(&sighand->siglock); | |
1424 | } | |
1425 | ||
1da177e4 LT |
1426 | void __init proc_caches_init(void) |
1427 | { | |
1428 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1429 | sizeof(struct sighand_struct), 0, | |
aa1757f9 ON |
1430 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
1431 | sighand_ctor, NULL); | |
1da177e4 LT |
1432 | signal_cachep = kmem_cache_create("signal_cache", |
1433 | sizeof(struct signal_struct), 0, | |
1434 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1435 | files_cachep = kmem_cache_create("files_cache", | |
1436 | sizeof(struct files_struct), 0, | |
1437 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1438 | fs_cachep = kmem_cache_create("fs_cache", | |
1439 | sizeof(struct fs_struct), 0, | |
1440 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1441 | vm_area_cachep = kmem_cache_create("vm_area_struct", | |
1442 | sizeof(struct vm_area_struct), 0, | |
1443 | SLAB_PANIC, NULL, NULL); | |
1444 | mm_cachep = kmem_cache_create("mm_struct", | |
5fd63b30 | 1445 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
1da177e4 LT |
1446 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
1447 | } | |
cf2e340f JD |
1448 | |
1449 | ||
1450 | /* | |
1451 | * Check constraints on flags passed to the unshare system call and | |
1452 | * force unsharing of additional process context as appropriate. | |
1453 | */ | |
1454 | static inline void check_unshare_flags(unsigned long *flags_ptr) | |
1455 | { | |
1456 | /* | |
1457 | * If unsharing a thread from a thread group, must also | |
1458 | * unshare vm. | |
1459 | */ | |
1460 | if (*flags_ptr & CLONE_THREAD) | |
1461 | *flags_ptr |= CLONE_VM; | |
1462 | ||
1463 | /* | |
1464 | * If unsharing vm, must also unshare signal handlers. | |
1465 | */ | |
1466 | if (*flags_ptr & CLONE_VM) | |
1467 | *flags_ptr |= CLONE_SIGHAND; | |
1468 | ||
1469 | /* | |
1470 | * If unsharing signal handlers and the task was created | |
1471 | * using CLONE_THREAD, then must unshare the thread | |
1472 | */ | |
1473 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1474 | (atomic_read(¤t->signal->count) > 1)) | |
1475 | *flags_ptr |= CLONE_THREAD; | |
1476 | ||
1477 | /* | |
1478 | * If unsharing namespace, must also unshare filesystem information. | |
1479 | */ | |
1480 | if (*flags_ptr & CLONE_NEWNS) | |
1481 | *flags_ptr |= CLONE_FS; | |
1482 | } | |
1483 | ||
1484 | /* | |
1485 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1486 | */ | |
1487 | static int unshare_thread(unsigned long unshare_flags) | |
1488 | { | |
1489 | if (unshare_flags & CLONE_THREAD) | |
1490 | return -EINVAL; | |
1491 | ||
1492 | return 0; | |
1493 | } | |
1494 | ||
1495 | /* | |
99d1419d | 1496 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1497 | */ |
1498 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1499 | { | |
1500 | struct fs_struct *fs = current->fs; | |
1501 | ||
1502 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1503 | (fs && atomic_read(&fs->count) > 1)) { |
1504 | *new_fsp = __copy_fs_struct(current->fs); | |
1505 | if (!*new_fsp) | |
1506 | return -ENOMEM; | |
1507 | } | |
cf2e340f JD |
1508 | |
1509 | return 0; | |
1510 | } | |
1511 | ||
1512 | /* | |
741a2951 | 1513 | * Unshare the namespace structure if it is being shared |
cf2e340f | 1514 | */ |
741a2951 | 1515 | static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs) |
cf2e340f JD |
1516 | { |
1517 | struct namespace *ns = current->namespace; | |
1518 | ||
1519 | if ((unshare_flags & CLONE_NEWNS) && | |
741a2951 JD |
1520 | (ns && atomic_read(&ns->count) > 1)) { |
1521 | if (!capable(CAP_SYS_ADMIN)) | |
1522 | return -EPERM; | |
1523 | ||
1524 | *new_nsp = dup_namespace(current, new_fs ? new_fs : current->fs); | |
1525 | if (!*new_nsp) | |
1526 | return -ENOMEM; | |
1527 | } | |
cf2e340f JD |
1528 | |
1529 | return 0; | |
1530 | } | |
1531 | ||
1532 | /* | |
1533 | * Unsharing of sighand for tasks created with CLONE_SIGHAND is not | |
1534 | * supported yet | |
1535 | */ | |
1536 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1537 | { | |
1538 | struct sighand_struct *sigh = current->sighand; | |
1539 | ||
1540 | if ((unshare_flags & CLONE_SIGHAND) && | |
1541 | (sigh && atomic_read(&sigh->count) > 1)) | |
1542 | return -EINVAL; | |
1543 | else | |
1544 | return 0; | |
1545 | } | |
1546 | ||
1547 | /* | |
a0a7ec30 | 1548 | * Unshare vm if it is being shared |
cf2e340f JD |
1549 | */ |
1550 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1551 | { | |
1552 | struct mm_struct *mm = current->mm; | |
1553 | ||
1554 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1555 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1556 | return -EINVAL; |
a0a7ec30 | 1557 | } |
cf2e340f JD |
1558 | |
1559 | return 0; | |
cf2e340f JD |
1560 | } |
1561 | ||
1562 | /* | |
a016f338 | 1563 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1564 | */ |
1565 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1566 | { | |
1567 | struct files_struct *fd = current->files; | |
a016f338 | 1568 | int error = 0; |
cf2e340f JD |
1569 | |
1570 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1571 | (fd && atomic_read(&fd->count) > 1)) { |
1572 | *new_fdp = dup_fd(fd, &error); | |
1573 | if (!*new_fdp) | |
1574 | return error; | |
1575 | } | |
cf2e340f JD |
1576 | |
1577 | return 0; | |
1578 | } | |
1579 | ||
1580 | /* | |
1581 | * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not | |
1582 | * supported yet | |
1583 | */ | |
1584 | static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp) | |
1585 | { | |
1586 | if (unshare_flags & CLONE_SYSVSEM) | |
1587 | return -EINVAL; | |
1588 | ||
1589 | return 0; | |
1590 | } | |
1591 | ||
1592 | /* | |
1593 | * unshare allows a process to 'unshare' part of the process | |
1594 | * context which was originally shared using clone. copy_* | |
1595 | * functions used by do_fork() cannot be used here directly | |
1596 | * because they modify an inactive task_struct that is being | |
1597 | * constructed. Here we are modifying the current, active, | |
1598 | * task_struct. | |
1599 | */ | |
1600 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1601 | { | |
1602 | int err = 0; | |
1603 | struct fs_struct *fs, *new_fs = NULL; | |
1604 | struct namespace *ns, *new_ns = NULL; | |
1605 | struct sighand_struct *sigh, *new_sigh = NULL; | |
1606 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; | |
1607 | struct files_struct *fd, *new_fd = NULL; | |
1608 | struct sem_undo_list *new_ulist = NULL; | |
1609 | ||
1610 | check_unshare_flags(&unshare_flags); | |
1611 | ||
06f9d4f9 EB |
1612 | /* Return -EINVAL for all unsupported flags */ |
1613 | err = -EINVAL; | |
1614 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
1615 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM)) | |
1616 | goto bad_unshare_out; | |
1617 | ||
cf2e340f JD |
1618 | if ((err = unshare_thread(unshare_flags))) |
1619 | goto bad_unshare_out; | |
1620 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1621 | goto bad_unshare_cleanup_thread; | |
741a2951 | 1622 | if ((err = unshare_namespace(unshare_flags, &new_ns, new_fs))) |
cf2e340f JD |
1623 | goto bad_unshare_cleanup_fs; |
1624 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) | |
1625 | goto bad_unshare_cleanup_ns; | |
1626 | if ((err = unshare_vm(unshare_flags, &new_mm))) | |
1627 | goto bad_unshare_cleanup_sigh; | |
1628 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1629 | goto bad_unshare_cleanup_vm; | |
1630 | if ((err = unshare_semundo(unshare_flags, &new_ulist))) | |
1631 | goto bad_unshare_cleanup_fd; | |
1632 | ||
1633 | if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) { | |
1634 | ||
1635 | task_lock(current); | |
1636 | ||
1637 | if (new_fs) { | |
1638 | fs = current->fs; | |
1639 | current->fs = new_fs; | |
1640 | new_fs = fs; | |
1641 | } | |
1642 | ||
1643 | if (new_ns) { | |
1644 | ns = current->namespace; | |
1645 | current->namespace = new_ns; | |
1646 | new_ns = ns; | |
1647 | } | |
1648 | ||
1649 | if (new_sigh) { | |
1650 | sigh = current->sighand; | |
e0e8eb54 | 1651 | rcu_assign_pointer(current->sighand, new_sigh); |
cf2e340f JD |
1652 | new_sigh = sigh; |
1653 | } | |
1654 | ||
1655 | if (new_mm) { | |
1656 | mm = current->mm; | |
1657 | active_mm = current->active_mm; | |
1658 | current->mm = new_mm; | |
1659 | current->active_mm = new_mm; | |
1660 | activate_mm(active_mm, new_mm); | |
1661 | new_mm = mm; | |
1662 | } | |
1663 | ||
1664 | if (new_fd) { | |
1665 | fd = current->files; | |
1666 | current->files = new_fd; | |
1667 | new_fd = fd; | |
1668 | } | |
1669 | ||
1670 | task_unlock(current); | |
1671 | } | |
1672 | ||
1673 | bad_unshare_cleanup_fd: | |
1674 | if (new_fd) | |
1675 | put_files_struct(new_fd); | |
1676 | ||
1677 | bad_unshare_cleanup_vm: | |
1678 | if (new_mm) | |
1679 | mmput(new_mm); | |
1680 | ||
1681 | bad_unshare_cleanup_sigh: | |
1682 | if (new_sigh) | |
1683 | if (atomic_dec_and_test(&new_sigh->count)) | |
1684 | kmem_cache_free(sighand_cachep, new_sigh); | |
1685 | ||
1686 | bad_unshare_cleanup_ns: | |
1687 | if (new_ns) | |
1688 | put_namespace(new_ns); | |
1689 | ||
1690 | bad_unshare_cleanup_fs: | |
1691 | if (new_fs) | |
1692 | put_fs_struct(new_fs); | |
1693 | ||
1694 | bad_unshare_cleanup_thread: | |
1695 | bad_unshare_out: | |
1696 | return err; | |
1697 | } |