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> |
ca74e92b | 46 | #include <linux/delayacct.h> |
ad4ecbcb | 47 | #include <linux/taskstats_kern.h> |
1da177e4 LT |
48 | |
49 | #include <asm/pgtable.h> | |
50 | #include <asm/pgalloc.h> | |
51 | #include <asm/uaccess.h> | |
52 | #include <asm/mmu_context.h> | |
53 | #include <asm/cacheflush.h> | |
54 | #include <asm/tlbflush.h> | |
55 | ||
56 | /* | |
57 | * Protected counters by write_lock_irq(&tasklist_lock) | |
58 | */ | |
59 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
60 | int nr_threads; /* The idle threads do not count.. */ | |
61 | ||
62 | int max_threads; /* tunable limit on nr_threads */ | |
63 | ||
64 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
65 | ||
c59923a1 | 66 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
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); | |
35df17c5 | 120 | delayacct_tsk_free(tsk); |
1da177e4 LT |
121 | |
122 | if (!profile_handoff_task(tsk)) | |
123 | free_task(tsk); | |
124 | } | |
125 | ||
126 | void __init fork_init(unsigned long mempages) | |
127 | { | |
128 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
129 | #ifndef ARCH_MIN_TASKALIGN | |
130 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
131 | #endif | |
132 | /* create a slab on which task_structs can be allocated */ | |
133 | task_struct_cachep = | |
134 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
135 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL); | |
136 | #endif | |
137 | ||
138 | /* | |
139 | * The default maximum number of threads is set to a safe | |
140 | * value: the thread structures can take up at most half | |
141 | * of memory. | |
142 | */ | |
143 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
144 | ||
145 | /* | |
146 | * we need to allow at least 20 threads to boot a system | |
147 | */ | |
148 | if(max_threads < 20) | |
149 | max_threads = 20; | |
150 | ||
151 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
152 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
153 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
154 | init_task.signal->rlim[RLIMIT_NPROC]; | |
155 | } | |
156 | ||
157 | static struct task_struct *dup_task_struct(struct task_struct *orig) | |
158 | { | |
159 | struct task_struct *tsk; | |
160 | struct thread_info *ti; | |
161 | ||
162 | prepare_to_copy(orig); | |
163 | ||
164 | tsk = alloc_task_struct(); | |
165 | if (!tsk) | |
166 | return NULL; | |
167 | ||
168 | ti = alloc_thread_info(tsk); | |
169 | if (!ti) { | |
170 | free_task_struct(tsk); | |
171 | return NULL; | |
172 | } | |
173 | ||
1da177e4 LT |
174 | *tsk = *orig; |
175 | tsk->thread_info = ti; | |
10ebffde | 176 | setup_thread_stack(tsk, orig); |
1da177e4 LT |
177 | |
178 | /* One for us, one for whoever does the "release_task()" (usually parent) */ | |
179 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 180 | atomic_set(&tsk->fs_excl, 0); |
2056a782 | 181 | tsk->btrace_seq = 0; |
a0aa7f68 | 182 | tsk->splice_pipe = NULL; |
1da177e4 LT |
183 | return tsk; |
184 | } | |
185 | ||
186 | #ifdef CONFIG_MMU | |
fd3e42fc | 187 | static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 188 | { |
fd3e42fc | 189 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
190 | struct rb_node **rb_link, *rb_parent; |
191 | int retval; | |
192 | unsigned long charge; | |
193 | struct mempolicy *pol; | |
194 | ||
195 | down_write(&oldmm->mmap_sem); | |
fd3e42fc | 196 | flush_cache_mm(oldmm); |
ad339451 IM |
197 | /* |
198 | * Not linked in yet - no deadlock potential: | |
199 | */ | |
200 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 201 | |
1da177e4 LT |
202 | mm->locked_vm = 0; |
203 | mm->mmap = NULL; | |
204 | mm->mmap_cache = NULL; | |
205 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 206 | mm->cached_hole_size = ~0UL; |
1da177e4 | 207 | mm->map_count = 0; |
1da177e4 LT |
208 | cpus_clear(mm->cpu_vm_mask); |
209 | mm->mm_rb = RB_ROOT; | |
210 | rb_link = &mm->mm_rb.rb_node; | |
211 | rb_parent = NULL; | |
212 | pprev = &mm->mmap; | |
213 | ||
fd3e42fc | 214 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
215 | struct file *file; |
216 | ||
217 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
218 | long pages = vma_pages(mpnt); |
219 | mm->total_vm -= pages; | |
ab50b8ed | 220 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 221 | -pages); |
1da177e4 LT |
222 | continue; |
223 | } | |
224 | charge = 0; | |
225 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
226 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
227 | if (security_vm_enough_memory(len)) | |
228 | goto fail_nomem; | |
229 | charge = len; | |
230 | } | |
231 | tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); | |
232 | if (!tmp) | |
233 | goto fail_nomem; | |
234 | *tmp = *mpnt; | |
235 | pol = mpol_copy(vma_policy(mpnt)); | |
236 | retval = PTR_ERR(pol); | |
237 | if (IS_ERR(pol)) | |
238 | goto fail_nomem_policy; | |
239 | vma_set_policy(tmp, pol); | |
240 | tmp->vm_flags &= ~VM_LOCKED; | |
241 | tmp->vm_mm = mm; | |
242 | tmp->vm_next = NULL; | |
243 | anon_vma_link(tmp); | |
244 | file = tmp->vm_file; | |
245 | if (file) { | |
246 | struct inode *inode = file->f_dentry->d_inode; | |
247 | get_file(file); | |
248 | if (tmp->vm_flags & VM_DENYWRITE) | |
249 | atomic_dec(&inode->i_writecount); | |
250 | ||
251 | /* insert tmp into the share list, just after mpnt */ | |
252 | spin_lock(&file->f_mapping->i_mmap_lock); | |
253 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
254 | flush_dcache_mmap_lock(file->f_mapping); | |
255 | vma_prio_tree_add(tmp, mpnt); | |
256 | flush_dcache_mmap_unlock(file->f_mapping); | |
257 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
258 | } | |
259 | ||
260 | /* | |
7ee78232 | 261 | * Link in the new vma and copy the page table entries. |
1da177e4 | 262 | */ |
1da177e4 LT |
263 | *pprev = tmp; |
264 | pprev = &tmp->vm_next; | |
265 | ||
266 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
267 | rb_link = &tmp->vm_rb.rb_right; | |
268 | rb_parent = &tmp->vm_rb; | |
269 | ||
270 | mm->map_count++; | |
0b0db14c | 271 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
272 | |
273 | if (tmp->vm_ops && tmp->vm_ops->open) | |
274 | tmp->vm_ops->open(tmp); | |
275 | ||
276 | if (retval) | |
277 | goto out; | |
278 | } | |
279 | retval = 0; | |
1da177e4 | 280 | out: |
7ee78232 | 281 | up_write(&mm->mmap_sem); |
fd3e42fc | 282 | flush_tlb_mm(oldmm); |
1da177e4 LT |
283 | up_write(&oldmm->mmap_sem); |
284 | return retval; | |
285 | fail_nomem_policy: | |
286 | kmem_cache_free(vm_area_cachep, tmp); | |
287 | fail_nomem: | |
288 | retval = -ENOMEM; | |
289 | vm_unacct_memory(charge); | |
290 | goto out; | |
291 | } | |
292 | ||
293 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
294 | { | |
295 | mm->pgd = pgd_alloc(mm); | |
296 | if (unlikely(!mm->pgd)) | |
297 | return -ENOMEM; | |
298 | return 0; | |
299 | } | |
300 | ||
301 | static inline void mm_free_pgd(struct mm_struct * mm) | |
302 | { | |
303 | pgd_free(mm->pgd); | |
304 | } | |
305 | #else | |
306 | #define dup_mmap(mm, oldmm) (0) | |
307 | #define mm_alloc_pgd(mm) (0) | |
308 | #define mm_free_pgd(mm) | |
309 | #endif /* CONFIG_MMU */ | |
310 | ||
311 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); | |
312 | ||
313 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL)) | |
314 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) | |
315 | ||
316 | #include <linux/init_task.h> | |
317 | ||
318 | static struct mm_struct * mm_init(struct mm_struct * mm) | |
319 | { | |
320 | atomic_set(&mm->mm_users, 1); | |
321 | atomic_set(&mm->mm_count, 1); | |
322 | init_rwsem(&mm->mmap_sem); | |
323 | INIT_LIST_HEAD(&mm->mmlist); | |
324 | mm->core_waiters = 0; | |
325 | mm->nr_ptes = 0; | |
4294621f | 326 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 327 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
328 | spin_lock_init(&mm->page_table_lock); |
329 | rwlock_init(&mm->ioctx_list_lock); | |
330 | mm->ioctx_list = NULL; | |
1da177e4 | 331 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 332 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
333 | |
334 | if (likely(!mm_alloc_pgd(mm))) { | |
335 | mm->def_flags = 0; | |
336 | return mm; | |
337 | } | |
338 | free_mm(mm); | |
339 | return NULL; | |
340 | } | |
341 | ||
342 | /* | |
343 | * Allocate and initialize an mm_struct. | |
344 | */ | |
345 | struct mm_struct * mm_alloc(void) | |
346 | { | |
347 | struct mm_struct * mm; | |
348 | ||
349 | mm = allocate_mm(); | |
350 | if (mm) { | |
351 | memset(mm, 0, sizeof(*mm)); | |
352 | mm = mm_init(mm); | |
353 | } | |
354 | return mm; | |
355 | } | |
356 | ||
357 | /* | |
358 | * Called when the last reference to the mm | |
359 | * is dropped: either by a lazy thread or by | |
360 | * mmput. Free the page directory and the mm. | |
361 | */ | |
362 | void fastcall __mmdrop(struct mm_struct *mm) | |
363 | { | |
364 | BUG_ON(mm == &init_mm); | |
365 | mm_free_pgd(mm); | |
366 | destroy_context(mm); | |
367 | free_mm(mm); | |
368 | } | |
369 | ||
370 | /* | |
371 | * Decrement the use count and release all resources for an mm. | |
372 | */ | |
373 | void mmput(struct mm_struct *mm) | |
374 | { | |
0ae26f1b AM |
375 | might_sleep(); |
376 | ||
1da177e4 LT |
377 | if (atomic_dec_and_test(&mm->mm_users)) { |
378 | exit_aio(mm); | |
379 | exit_mmap(mm); | |
380 | if (!list_empty(&mm->mmlist)) { | |
381 | spin_lock(&mmlist_lock); | |
382 | list_del(&mm->mmlist); | |
383 | spin_unlock(&mmlist_lock); | |
384 | } | |
385 | put_swap_token(mm); | |
386 | mmdrop(mm); | |
387 | } | |
388 | } | |
389 | EXPORT_SYMBOL_GPL(mmput); | |
390 | ||
391 | /** | |
392 | * get_task_mm - acquire a reference to the task's mm | |
393 | * | |
394 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning | |
395 | * this kernel workthread has transiently adopted a user mm with use_mm, | |
396 | * to do its AIO) is not set and if so returns a reference to it, after | |
397 | * bumping up the use count. User must release the mm via mmput() | |
398 | * after use. Typically used by /proc and ptrace. | |
399 | */ | |
400 | struct mm_struct *get_task_mm(struct task_struct *task) | |
401 | { | |
402 | struct mm_struct *mm; | |
403 | ||
404 | task_lock(task); | |
405 | mm = task->mm; | |
406 | if (mm) { | |
407 | if (task->flags & PF_BORROWED_MM) | |
408 | mm = NULL; | |
409 | else | |
410 | atomic_inc(&mm->mm_users); | |
411 | } | |
412 | task_unlock(task); | |
413 | return mm; | |
414 | } | |
415 | EXPORT_SYMBOL_GPL(get_task_mm); | |
416 | ||
417 | /* Please note the differences between mmput and mm_release. | |
418 | * mmput is called whenever we stop holding onto a mm_struct, | |
419 | * error success whatever. | |
420 | * | |
421 | * mm_release is called after a mm_struct has been removed | |
422 | * from the current process. | |
423 | * | |
424 | * This difference is important for error handling, when we | |
425 | * only half set up a mm_struct for a new process and need to restore | |
426 | * the old one. Because we mmput the new mm_struct before | |
427 | * restoring the old one. . . | |
428 | * Eric Biederman 10 January 1998 | |
429 | */ | |
430 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
431 | { | |
432 | struct completion *vfork_done = tsk->vfork_done; | |
433 | ||
434 | /* Get rid of any cached register state */ | |
435 | deactivate_mm(tsk, mm); | |
436 | ||
437 | /* notify parent sleeping on vfork() */ | |
438 | if (vfork_done) { | |
439 | tsk->vfork_done = NULL; | |
440 | complete(vfork_done); | |
441 | } | |
442 | if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) { | |
443 | u32 __user * tidptr = tsk->clear_child_tid; | |
444 | tsk->clear_child_tid = NULL; | |
445 | ||
446 | /* | |
447 | * We don't check the error code - if userspace has | |
448 | * not set up a proper pointer then tough luck. | |
449 | */ | |
450 | put_user(0, tidptr); | |
451 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
452 | } | |
453 | } | |
454 | ||
a0a7ec30 JD |
455 | /* |
456 | * Allocate a new mm structure and copy contents from the | |
457 | * mm structure of the passed in task structure. | |
458 | */ | |
459 | static struct mm_struct *dup_mm(struct task_struct *tsk) | |
460 | { | |
461 | struct mm_struct *mm, *oldmm = current->mm; | |
462 | int err; | |
463 | ||
464 | if (!oldmm) | |
465 | return NULL; | |
466 | ||
467 | mm = allocate_mm(); | |
468 | if (!mm) | |
469 | goto fail_nomem; | |
470 | ||
471 | memcpy(mm, oldmm, sizeof(*mm)); | |
472 | ||
473 | if (!mm_init(mm)) | |
474 | goto fail_nomem; | |
475 | ||
476 | if (init_new_context(tsk, mm)) | |
477 | goto fail_nocontext; | |
478 | ||
479 | err = dup_mmap(mm, oldmm); | |
480 | if (err) | |
481 | goto free_pt; | |
482 | ||
483 | mm->hiwater_rss = get_mm_rss(mm); | |
484 | mm->hiwater_vm = mm->total_vm; | |
485 | ||
486 | return mm; | |
487 | ||
488 | free_pt: | |
489 | mmput(mm); | |
490 | ||
491 | fail_nomem: | |
492 | return NULL; | |
493 | ||
494 | fail_nocontext: | |
495 | /* | |
496 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
497 | * because it calls destroy_context() | |
498 | */ | |
499 | mm_free_pgd(mm); | |
500 | free_mm(mm); | |
501 | return NULL; | |
502 | } | |
503 | ||
1da177e4 LT |
504 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
505 | { | |
506 | struct mm_struct * mm, *oldmm; | |
507 | int retval; | |
508 | ||
509 | tsk->min_flt = tsk->maj_flt = 0; | |
510 | tsk->nvcsw = tsk->nivcsw = 0; | |
511 | ||
512 | tsk->mm = NULL; | |
513 | tsk->active_mm = NULL; | |
514 | ||
515 | /* | |
516 | * Are we cloning a kernel thread? | |
517 | * | |
518 | * We need to steal a active VM for that.. | |
519 | */ | |
520 | oldmm = current->mm; | |
521 | if (!oldmm) | |
522 | return 0; | |
523 | ||
524 | if (clone_flags & CLONE_VM) { | |
525 | atomic_inc(&oldmm->mm_users); | |
526 | mm = oldmm; | |
1da177e4 LT |
527 | goto good_mm; |
528 | } | |
529 | ||
530 | retval = -ENOMEM; | |
a0a7ec30 | 531 | mm = dup_mm(tsk); |
1da177e4 LT |
532 | if (!mm) |
533 | goto fail_nomem; | |
534 | ||
1da177e4 LT |
535 | good_mm: |
536 | tsk->mm = mm; | |
537 | tsk->active_mm = mm; | |
538 | return 0; | |
539 | ||
1da177e4 LT |
540 | fail_nomem: |
541 | return retval; | |
1da177e4 LT |
542 | } |
543 | ||
544 | static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old) | |
545 | { | |
546 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
547 | /* We don't need to lock fs - think why ;-) */ | |
548 | if (fs) { | |
549 | atomic_set(&fs->count, 1); | |
550 | rwlock_init(&fs->lock); | |
551 | fs->umask = old->umask; | |
552 | read_lock(&old->lock); | |
553 | fs->rootmnt = mntget(old->rootmnt); | |
554 | fs->root = dget(old->root); | |
555 | fs->pwdmnt = mntget(old->pwdmnt); | |
556 | fs->pwd = dget(old->pwd); | |
557 | if (old->altroot) { | |
558 | fs->altrootmnt = mntget(old->altrootmnt); | |
559 | fs->altroot = dget(old->altroot); | |
560 | } else { | |
561 | fs->altrootmnt = NULL; | |
562 | fs->altroot = NULL; | |
563 | } | |
564 | read_unlock(&old->lock); | |
565 | } | |
566 | return fs; | |
567 | } | |
568 | ||
569 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
570 | { | |
571 | return __copy_fs_struct(old); | |
572 | } | |
573 | ||
574 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
575 | ||
576 | static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk) | |
577 | { | |
578 | if (clone_flags & CLONE_FS) { | |
579 | atomic_inc(¤t->fs->count); | |
580 | return 0; | |
581 | } | |
582 | tsk->fs = __copy_fs_struct(current->fs); | |
583 | if (!tsk->fs) | |
584 | return -ENOMEM; | |
585 | return 0; | |
586 | } | |
587 | ||
ab2af1f5 | 588 | static int count_open_files(struct fdtable *fdt) |
1da177e4 | 589 | { |
ab2af1f5 | 590 | int size = fdt->max_fdset; |
1da177e4 LT |
591 | int i; |
592 | ||
593 | /* Find the last open fd */ | |
594 | for (i = size/(8*sizeof(long)); i > 0; ) { | |
badf1662 | 595 | if (fdt->open_fds->fds_bits[--i]) |
1da177e4 LT |
596 | break; |
597 | } | |
598 | i = (i+1) * 8 * sizeof(long); | |
599 | return i; | |
600 | } | |
601 | ||
badf1662 DS |
602 | static struct files_struct *alloc_files(void) |
603 | { | |
604 | struct files_struct *newf; | |
605 | struct fdtable *fdt; | |
606 | ||
607 | newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL); | |
608 | if (!newf) | |
609 | goto out; | |
610 | ||
611 | atomic_set(&newf->count, 1); | |
612 | ||
613 | spin_lock_init(&newf->file_lock); | |
0c9e63fd | 614 | newf->next_fd = 0; |
ab2af1f5 | 615 | fdt = &newf->fdtab; |
badf1662 | 616 | fdt->max_fds = NR_OPEN_DEFAULT; |
0c9e63fd ED |
617 | fdt->max_fdset = EMBEDDED_FD_SET_SIZE; |
618 | fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init; | |
619 | fdt->open_fds = (fd_set *)&newf->open_fds_init; | |
badf1662 | 620 | fdt->fd = &newf->fd_array[0]; |
ab2af1f5 DS |
621 | INIT_RCU_HEAD(&fdt->rcu); |
622 | fdt->free_files = NULL; | |
623 | fdt->next = NULL; | |
624 | rcu_assign_pointer(newf->fdt, fdt); | |
badf1662 DS |
625 | out: |
626 | return newf; | |
627 | } | |
628 | ||
a016f338 JD |
629 | /* |
630 | * Allocate a new files structure and copy contents from the | |
631 | * passed in files structure. | |
6e667260 | 632 | * errorp will be valid only when the returned files_struct is NULL. |
a016f338 JD |
633 | */ |
634 | static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) | |
1da177e4 | 635 | { |
a016f338 | 636 | struct files_struct *newf; |
1da177e4 | 637 | struct file **old_fds, **new_fds; |
a016f338 | 638 | int open_files, size, i, expand; |
badf1662 | 639 | struct fdtable *old_fdt, *new_fdt; |
1da177e4 | 640 | |
6e667260 | 641 | *errorp = -ENOMEM; |
badf1662 DS |
642 | newf = alloc_files(); |
643 | if (!newf) | |
1da177e4 LT |
644 | goto out; |
645 | ||
1da177e4 | 646 | spin_lock(&oldf->file_lock); |
badf1662 DS |
647 | old_fdt = files_fdtable(oldf); |
648 | new_fdt = files_fdtable(newf); | |
649 | size = old_fdt->max_fdset; | |
ab2af1f5 | 650 | open_files = count_open_files(old_fdt); |
1da177e4 LT |
651 | expand = 0; |
652 | ||
653 | /* | |
654 | * Check whether we need to allocate a larger fd array or fd set. | |
655 | * Note: we're not a clone task, so the open count won't change. | |
656 | */ | |
badf1662 DS |
657 | if (open_files > new_fdt->max_fdset) { |
658 | new_fdt->max_fdset = 0; | |
1da177e4 LT |
659 | expand = 1; |
660 | } | |
badf1662 DS |
661 | if (open_files > new_fdt->max_fds) { |
662 | new_fdt->max_fds = 0; | |
1da177e4 LT |
663 | expand = 1; |
664 | } | |
665 | ||
666 | /* if the old fdset gets grown now, we'll only copy up to "size" fds */ | |
667 | if (expand) { | |
668 | spin_unlock(&oldf->file_lock); | |
669 | spin_lock(&newf->file_lock); | |
a016f338 | 670 | *errorp = expand_files(newf, open_files-1); |
1da177e4 | 671 | spin_unlock(&newf->file_lock); |
a016f338 | 672 | if (*errorp < 0) |
1da177e4 | 673 | goto out_release; |
ab2af1f5 DS |
674 | new_fdt = files_fdtable(newf); |
675 | /* | |
676 | * Reacquire the oldf lock and a pointer to its fd table | |
677 | * who knows it may have a new bigger fd table. We need | |
678 | * the latest pointer. | |
679 | */ | |
1da177e4 | 680 | spin_lock(&oldf->file_lock); |
ab2af1f5 | 681 | old_fdt = files_fdtable(oldf); |
1da177e4 LT |
682 | } |
683 | ||
badf1662 DS |
684 | old_fds = old_fdt->fd; |
685 | new_fds = new_fdt->fd; | |
1da177e4 | 686 | |
badf1662 DS |
687 | memcpy(new_fdt->open_fds->fds_bits, old_fdt->open_fds->fds_bits, open_files/8); |
688 | memcpy(new_fdt->close_on_exec->fds_bits, old_fdt->close_on_exec->fds_bits, open_files/8); | |
1da177e4 LT |
689 | |
690 | for (i = open_files; i != 0; i--) { | |
691 | struct file *f = *old_fds++; | |
692 | if (f) { | |
693 | get_file(f); | |
694 | } else { | |
695 | /* | |
696 | * The fd may be claimed in the fd bitmap but not yet | |
697 | * instantiated in the files array if a sibling thread | |
698 | * is partway through open(). So make sure that this | |
699 | * fd is available to the new process. | |
700 | */ | |
badf1662 | 701 | FD_CLR(open_files - i, new_fdt->open_fds); |
1da177e4 | 702 | } |
ab2af1f5 | 703 | rcu_assign_pointer(*new_fds++, f); |
1da177e4 LT |
704 | } |
705 | spin_unlock(&oldf->file_lock); | |
706 | ||
707 | /* compute the remainder to be cleared */ | |
badf1662 | 708 | size = (new_fdt->max_fds - open_files) * sizeof(struct file *); |
1da177e4 LT |
709 | |
710 | /* This is long word aligned thus could use a optimized version */ | |
711 | memset(new_fds, 0, size); | |
712 | ||
badf1662 DS |
713 | if (new_fdt->max_fdset > open_files) { |
714 | int left = (new_fdt->max_fdset-open_files)/8; | |
1da177e4 LT |
715 | int start = open_files / (8 * sizeof(unsigned long)); |
716 | ||
badf1662 DS |
717 | memset(&new_fdt->open_fds->fds_bits[start], 0, left); |
718 | memset(&new_fdt->close_on_exec->fds_bits[start], 0, left); | |
1da177e4 LT |
719 | } |
720 | ||
1da177e4 | 721 | out: |
a016f338 | 722 | return newf; |
1da177e4 LT |
723 | |
724 | out_release: | |
badf1662 DS |
725 | free_fdset (new_fdt->close_on_exec, new_fdt->max_fdset); |
726 | free_fdset (new_fdt->open_fds, new_fdt->max_fdset); | |
727 | free_fd_array(new_fdt->fd, new_fdt->max_fds); | |
1da177e4 | 728 | kmem_cache_free(files_cachep, newf); |
42862298 | 729 | return NULL; |
1da177e4 LT |
730 | } |
731 | ||
a016f338 JD |
732 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
733 | { | |
734 | struct files_struct *oldf, *newf; | |
735 | int error = 0; | |
736 | ||
737 | /* | |
738 | * A background process may not have any files ... | |
739 | */ | |
740 | oldf = current->files; | |
741 | if (!oldf) | |
742 | goto out; | |
743 | ||
744 | if (clone_flags & CLONE_FILES) { | |
745 | atomic_inc(&oldf->count); | |
746 | goto out; | |
747 | } | |
748 | ||
749 | /* | |
750 | * Note: we may be using current for both targets (See exec.c) | |
751 | * This works because we cache current->files (old) as oldf. Don't | |
752 | * break this. | |
753 | */ | |
754 | tsk->files = NULL; | |
a016f338 JD |
755 | newf = dup_fd(oldf, &error); |
756 | if (!newf) | |
757 | goto out; | |
758 | ||
759 | tsk->files = newf; | |
760 | error = 0; | |
761 | out: | |
762 | return error; | |
763 | } | |
764 | ||
1da177e4 LT |
765 | /* |
766 | * Helper to unshare the files of the current task. | |
767 | * We don't want to expose copy_files internals to | |
768 | * the exec layer of the kernel. | |
769 | */ | |
770 | ||
771 | int unshare_files(void) | |
772 | { | |
773 | struct files_struct *files = current->files; | |
774 | int rc; | |
775 | ||
910dea7f | 776 | BUG_ON(!files); |
1da177e4 LT |
777 | |
778 | /* This can race but the race causes us to copy when we don't | |
779 | need to and drop the copy */ | |
780 | if(atomic_read(&files->count) == 1) | |
781 | { | |
782 | atomic_inc(&files->count); | |
783 | return 0; | |
784 | } | |
785 | rc = copy_files(0, current); | |
786 | if(rc) | |
787 | current->files = files; | |
788 | return rc; | |
789 | } | |
790 | ||
791 | EXPORT_SYMBOL(unshare_files); | |
792 | ||
793 | static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk) | |
794 | { | |
795 | struct sighand_struct *sig; | |
796 | ||
797 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
798 | atomic_inc(¤t->sighand->count); | |
799 | return 0; | |
800 | } | |
801 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 802 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
803 | if (!sig) |
804 | return -ENOMEM; | |
1da177e4 LT |
805 | atomic_set(&sig->count, 1); |
806 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
807 | return 0; | |
808 | } | |
809 | ||
a7e5328a | 810 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 811 | { |
c81addc9 ON |
812 | if (atomic_dec_and_test(&sighand->count)) |
813 | kmem_cache_free(sighand_cachep, sighand); | |
814 | } | |
815 | ||
1da177e4 LT |
816 | static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk) |
817 | { | |
818 | struct signal_struct *sig; | |
819 | int ret; | |
820 | ||
821 | if (clone_flags & CLONE_THREAD) { | |
822 | atomic_inc(¤t->signal->count); | |
823 | atomic_inc(¤t->signal->live); | |
ad4ecbcb | 824 | taskstats_tgid_alloc(current->signal); |
1da177e4 LT |
825 | return 0; |
826 | } | |
827 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
828 | tsk->signal = sig; | |
829 | if (!sig) | |
830 | return -ENOMEM; | |
831 | ||
832 | ret = copy_thread_group_keys(tsk); | |
833 | if (ret < 0) { | |
834 | kmem_cache_free(signal_cachep, sig); | |
835 | return ret; | |
836 | } | |
837 | ||
838 | atomic_set(&sig->count, 1); | |
839 | atomic_set(&sig->live, 1); | |
840 | init_waitqueue_head(&sig->wait_chldexit); | |
841 | sig->flags = 0; | |
842 | sig->group_exit_code = 0; | |
843 | sig->group_exit_task = NULL; | |
844 | sig->group_stop_count = 0; | |
845 | sig->curr_target = NULL; | |
846 | init_sigpending(&sig->shared_pending); | |
847 | INIT_LIST_HEAD(&sig->posix_timers); | |
848 | ||
7978672c | 849 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL); |
2ff678b8 | 850 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 851 | sig->real_timer.function = it_real_fn; |
05cfb614 | 852 | sig->tsk = tsk; |
1da177e4 LT |
853 | |
854 | sig->it_virt_expires = cputime_zero; | |
855 | sig->it_virt_incr = cputime_zero; | |
856 | sig->it_prof_expires = cputime_zero; | |
857 | sig->it_prof_incr = cputime_zero; | |
858 | ||
1da177e4 LT |
859 | sig->leader = 0; /* session leadership doesn't inherit */ |
860 | sig->tty_old_pgrp = 0; | |
861 | ||
862 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
863 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; | |
864 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
865 | sig->sched_time = 0; | |
866 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
867 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
868 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
ad4ecbcb | 869 | taskstats_tgid_init(sig); |
1da177e4 LT |
870 | |
871 | task_lock(current->group_leader); | |
872 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
873 | task_unlock(current->group_leader); | |
874 | ||
875 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
876 | /* | |
877 | * New sole thread in the process gets an expiry time | |
878 | * of the whole CPU time limit. | |
879 | */ | |
880 | tsk->it_prof_expires = | |
881 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
882 | } | |
0e464814 | 883 | acct_init_pacct(&sig->pacct); |
1da177e4 LT |
884 | |
885 | return 0; | |
886 | } | |
887 | ||
6b3934ef ON |
888 | void __cleanup_signal(struct signal_struct *sig) |
889 | { | |
890 | exit_thread_group_keys(sig); | |
ad4ecbcb | 891 | taskstats_tgid_free(sig); |
6b3934ef ON |
892 | kmem_cache_free(signal_cachep, sig); |
893 | } | |
894 | ||
895 | static inline void cleanup_signal(struct task_struct *tsk) | |
896 | { | |
897 | struct signal_struct *sig = tsk->signal; | |
898 | ||
899 | atomic_dec(&sig->live); | |
900 | ||
901 | if (atomic_dec_and_test(&sig->count)) | |
902 | __cleanup_signal(sig); | |
903 | } | |
904 | ||
1da177e4 LT |
905 | static inline void copy_flags(unsigned long clone_flags, struct task_struct *p) |
906 | { | |
907 | unsigned long new_flags = p->flags; | |
908 | ||
d1209d04 | 909 | new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE); |
1da177e4 LT |
910 | new_flags |= PF_FORKNOEXEC; |
911 | if (!(clone_flags & CLONE_PTRACE)) | |
912 | p->ptrace = 0; | |
913 | p->flags = new_flags; | |
914 | } | |
915 | ||
916 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
917 | { | |
918 | current->clear_child_tid = tidptr; | |
919 | ||
920 | return current->pid; | |
921 | } | |
922 | ||
23f78d4a IM |
923 | static inline void rt_mutex_init_task(struct task_struct *p) |
924 | { | |
925 | #ifdef CONFIG_RT_MUTEXES | |
926 | spin_lock_init(&p->pi_lock); | |
927 | plist_head_init(&p->pi_waiters, &p->pi_lock); | |
928 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
929 | #endif |
930 | } | |
931 | ||
1da177e4 LT |
932 | /* |
933 | * This creates a new process as a copy of the old one, | |
934 | * but does not actually start it yet. | |
935 | * | |
936 | * It copies the registers, and all the appropriate | |
937 | * parts of the process environment (as per the clone | |
938 | * flags). The actual kick-off is left to the caller. | |
939 | */ | |
36c8b586 IM |
940 | static struct task_struct *copy_process(unsigned long clone_flags, |
941 | unsigned long stack_start, | |
942 | struct pt_regs *regs, | |
943 | unsigned long stack_size, | |
944 | int __user *parent_tidptr, | |
945 | int __user *child_tidptr, | |
946 | int pid) | |
1da177e4 LT |
947 | { |
948 | int retval; | |
949 | struct task_struct *p = NULL; | |
950 | ||
951 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
952 | return ERR_PTR(-EINVAL); | |
953 | ||
954 | /* | |
955 | * Thread groups must share signals as well, and detached threads | |
956 | * can only be started up within the thread group. | |
957 | */ | |
958 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
959 | return ERR_PTR(-EINVAL); | |
960 | ||
961 | /* | |
962 | * Shared signal handlers imply shared VM. By way of the above, | |
963 | * thread groups also imply shared VM. Blocking this case allows | |
964 | * for various simplifications in other code. | |
965 | */ | |
966 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
967 | return ERR_PTR(-EINVAL); | |
968 | ||
969 | retval = security_task_create(clone_flags); | |
970 | if (retval) | |
971 | goto fork_out; | |
972 | ||
973 | retval = -ENOMEM; | |
974 | p = dup_task_struct(current); | |
975 | if (!p) | |
976 | goto fork_out; | |
977 | ||
de30a2b3 IM |
978 | #ifdef CONFIG_TRACE_IRQFLAGS |
979 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); | |
980 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
981 | #endif | |
1da177e4 LT |
982 | retval = -EAGAIN; |
983 | if (atomic_read(&p->user->processes) >= | |
984 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
985 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
986 | p->user != &root_user) | |
987 | goto bad_fork_free; | |
988 | } | |
989 | ||
990 | atomic_inc(&p->user->__count); | |
991 | atomic_inc(&p->user->processes); | |
992 | get_group_info(p->group_info); | |
993 | ||
994 | /* | |
995 | * If multiple threads are within copy_process(), then this check | |
996 | * triggers too late. This doesn't hurt, the check is only there | |
997 | * to stop root fork bombs. | |
998 | */ | |
999 | if (nr_threads >= max_threads) | |
1000 | goto bad_fork_cleanup_count; | |
1001 | ||
a1261f54 | 1002 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1003 | goto bad_fork_cleanup_count; |
1004 | ||
1005 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
1006 | goto bad_fork_cleanup_put_domain; | |
1007 | ||
1008 | p->did_exec = 0; | |
ca74e92b | 1009 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 LT |
1010 | copy_flags(clone_flags, p); |
1011 | p->pid = pid; | |
1012 | retval = -EFAULT; | |
1013 | if (clone_flags & CLONE_PARENT_SETTID) | |
1014 | if (put_user(p->pid, parent_tidptr)) | |
35df17c5 | 1015 | goto bad_fork_cleanup_delays_binfmt; |
1da177e4 | 1016 | |
1da177e4 LT |
1017 | INIT_LIST_HEAD(&p->children); |
1018 | INIT_LIST_HEAD(&p->sibling); | |
1019 | p->vfork_done = NULL; | |
1020 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
1021 | |
1022 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
1023 | init_sigpending(&p->pending); | |
1024 | ||
1025 | p->utime = cputime_zero; | |
1026 | p->stime = cputime_zero; | |
1027 | p->sched_time = 0; | |
1028 | p->rchar = 0; /* I/O counter: bytes read */ | |
1029 | p->wchar = 0; /* I/O counter: bytes written */ | |
1030 | p->syscr = 0; /* I/O counter: read syscalls */ | |
1031 | p->syscw = 0; /* I/O counter: write syscalls */ | |
1032 | acct_clear_integrals(p); | |
1033 | ||
1034 | p->it_virt_expires = cputime_zero; | |
1035 | p->it_prof_expires = cputime_zero; | |
1036 | p->it_sched_expires = 0; | |
1037 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1038 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1039 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1040 | ||
1041 | p->lock_depth = -1; /* -1 = no lock */ | |
1042 | do_posix_clock_monotonic_gettime(&p->start_time); | |
1043 | p->security = NULL; | |
1044 | p->io_context = NULL; | |
1045 | p->io_wait = NULL; | |
1046 | p->audit_context = NULL; | |
b4b26418 | 1047 | cpuset_fork(p); |
1da177e4 LT |
1048 | #ifdef CONFIG_NUMA |
1049 | p->mempolicy = mpol_copy(p->mempolicy); | |
1050 | if (IS_ERR(p->mempolicy)) { | |
1051 | retval = PTR_ERR(p->mempolicy); | |
1052 | p->mempolicy = NULL; | |
b4b26418 | 1053 | goto bad_fork_cleanup_cpuset; |
1da177e4 | 1054 | } |
c61afb18 | 1055 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1056 | #endif |
de30a2b3 IM |
1057 | #ifdef CONFIG_TRACE_IRQFLAGS |
1058 | p->irq_events = 0; | |
1059 | p->hardirqs_enabled = 0; | |
1060 | p->hardirq_enable_ip = 0; | |
1061 | p->hardirq_enable_event = 0; | |
1062 | p->hardirq_disable_ip = _THIS_IP_; | |
1063 | p->hardirq_disable_event = 0; | |
1064 | p->softirqs_enabled = 1; | |
1065 | p->softirq_enable_ip = _THIS_IP_; | |
1066 | p->softirq_enable_event = 0; | |
1067 | p->softirq_disable_ip = 0; | |
1068 | p->softirq_disable_event = 0; | |
1069 | p->hardirq_context = 0; | |
1070 | p->softirq_context = 0; | |
1071 | #endif | |
fbb9ce95 IM |
1072 | #ifdef CONFIG_LOCKDEP |
1073 | p->lockdep_depth = 0; /* no locks held yet */ | |
1074 | p->curr_chain_key = 0; | |
1075 | p->lockdep_recursion = 0; | |
1076 | #endif | |
1da177e4 | 1077 | |
23f78d4a IM |
1078 | rt_mutex_init_task(p); |
1079 | ||
408894ee IM |
1080 | #ifdef CONFIG_DEBUG_MUTEXES |
1081 | p->blocked_on = NULL; /* not blocked yet */ | |
1082 | #endif | |
1083 | ||
1da177e4 LT |
1084 | p->tgid = p->pid; |
1085 | if (clone_flags & CLONE_THREAD) | |
1086 | p->tgid = current->tgid; | |
1087 | ||
1088 | if ((retval = security_task_alloc(p))) | |
1089 | goto bad_fork_cleanup_policy; | |
1090 | if ((retval = audit_alloc(p))) | |
1091 | goto bad_fork_cleanup_security; | |
1092 | /* copy all the process information */ | |
1093 | if ((retval = copy_semundo(clone_flags, p))) | |
1094 | goto bad_fork_cleanup_audit; | |
1095 | if ((retval = copy_files(clone_flags, p))) | |
1096 | goto bad_fork_cleanup_semundo; | |
1097 | if ((retval = copy_fs(clone_flags, p))) | |
1098 | goto bad_fork_cleanup_files; | |
1099 | if ((retval = copy_sighand(clone_flags, p))) | |
1100 | goto bad_fork_cleanup_fs; | |
1101 | if ((retval = copy_signal(clone_flags, p))) | |
1102 | goto bad_fork_cleanup_sighand; | |
1103 | if ((retval = copy_mm(clone_flags, p))) | |
1104 | goto bad_fork_cleanup_signal; | |
1105 | if ((retval = copy_keys(clone_flags, p))) | |
1106 | goto bad_fork_cleanup_mm; | |
1107 | if ((retval = copy_namespace(clone_flags, p))) | |
1108 | goto bad_fork_cleanup_keys; | |
1109 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); | |
1110 | if (retval) | |
1111 | goto bad_fork_cleanup_namespace; | |
1112 | ||
1113 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; | |
1114 | /* | |
1115 | * Clear TID on mm_release()? | |
1116 | */ | |
1117 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
8f17d3a5 IM |
1118 | p->robust_list = NULL; |
1119 | #ifdef CONFIG_COMPAT | |
1120 | p->compat_robust_list = NULL; | |
1121 | #endif | |
c87e2837 IM |
1122 | INIT_LIST_HEAD(&p->pi_state_list); |
1123 | p->pi_state_cache = NULL; | |
1124 | ||
f9a3879a GM |
1125 | /* |
1126 | * sigaltstack should be cleared when sharing the same VM | |
1127 | */ | |
1128 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1129 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1130 | ||
1da177e4 LT |
1131 | /* |
1132 | * Syscall tracing should be turned off in the child regardless | |
1133 | * of CLONE_PTRACE. | |
1134 | */ | |
1135 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1136 | #ifdef TIF_SYSCALL_EMU |
1137 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1138 | #endif | |
1da177e4 LT |
1139 | |
1140 | /* Our parent execution domain becomes current domain | |
1141 | These must match for thread signalling to apply */ | |
1142 | ||
1143 | p->parent_exec_id = p->self_exec_id; | |
1144 | ||
1145 | /* ok, now we should be set up.. */ | |
1146 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1147 | p->pdeath_signal = 0; | |
1148 | p->exit_state = 0; | |
1149 | ||
1da177e4 LT |
1150 | /* |
1151 | * Ok, make it visible to the rest of the system. | |
1152 | * We dont wake it up yet. | |
1153 | */ | |
1154 | p->group_leader = p; | |
47e65328 | 1155 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 LT |
1156 | INIT_LIST_HEAD(&p->ptrace_children); |
1157 | INIT_LIST_HEAD(&p->ptrace_list); | |
1158 | ||
476d139c NP |
1159 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1160 | sched_fork(p, clone_flags); | |
1161 | ||
1da177e4 LT |
1162 | /* Need tasklist lock for parent etc handling! */ |
1163 | write_lock_irq(&tasklist_lock); | |
1164 | ||
1165 | /* | |
476d139c NP |
1166 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1167 | * not be changed, nor will its assigned CPU. | |
1168 | * | |
1169 | * The cpus_allowed mask of the parent may have changed after it was | |
1170 | * copied first time - so re-copy it here, then check the child's CPU | |
1171 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1172 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1173 | */ |
1174 | p->cpus_allowed = current->cpus_allowed; | |
26ff6ad9 SV |
1175 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1176 | !cpu_online(task_cpu(p)))) | |
476d139c | 1177 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1178 | |
1da177e4 LT |
1179 | /* CLONE_PARENT re-uses the old parent */ |
1180 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1181 | p->real_parent = current->real_parent; | |
1182 | else | |
1183 | p->real_parent = current; | |
1184 | p->parent = p->real_parent; | |
1185 | ||
3f17da69 | 1186 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1187 | |
1188 | /* | |
1189 | * Process group and session signals need to be delivered to just the | |
1190 | * parent before the fork or both the parent and the child after the | |
1191 | * fork. Restart if a signal comes in before we add the new process to | |
1192 | * it's process group. | |
1193 | * A fatal signal pending means that current will exit, so the new | |
1194 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1195 | */ | |
1196 | recalc_sigpending(); | |
1197 | if (signal_pending(current)) { | |
1198 | spin_unlock(¤t->sighand->siglock); | |
1199 | write_unlock_irq(&tasklist_lock); | |
1200 | retval = -ERESTARTNOINTR; | |
1201 | goto bad_fork_cleanup_namespace; | |
1202 | } | |
1203 | ||
1da177e4 | 1204 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1205 | p->group_leader = current->group_leader; |
47e65328 | 1206 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1207 | |
1da177e4 LT |
1208 | if (!cputime_eq(current->signal->it_virt_expires, |
1209 | cputime_zero) || | |
1210 | !cputime_eq(current->signal->it_prof_expires, | |
1211 | cputime_zero) || | |
1212 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1213 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1214 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1215 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1216 | /* | |
1217 | * Have child wake up on its first tick to check | |
1218 | * for process CPU timers. | |
1219 | */ | |
1220 | p->it_prof_expires = jiffies_to_cputime(1); | |
1221 | } | |
1da177e4 LT |
1222 | } |
1223 | ||
22e2c507 JA |
1224 | /* |
1225 | * inherit ioprio | |
1226 | */ | |
1227 | p->ioprio = current->ioprio; | |
1228 | ||
73b9ebfe ON |
1229 | if (likely(p->pid)) { |
1230 | add_parent(p); | |
1231 | if (unlikely(p->ptrace & PT_PTRACED)) | |
1232 | __ptrace_link(p, current->parent); | |
1233 | ||
1234 | if (thread_group_leader(p)) { | |
1235 | p->signal->tty = current->signal->tty; | |
1236 | p->signal->pgrp = process_group(current); | |
1237 | p->signal->session = current->signal->session; | |
1238 | attach_pid(p, PIDTYPE_PGID, process_group(p)); | |
1239 | attach_pid(p, PIDTYPE_SID, p->signal->session); | |
1240 | ||
5e85d4ab | 1241 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1242 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1243 | } |
73b9ebfe ON |
1244 | attach_pid(p, PIDTYPE_PID, p->pid); |
1245 | nr_threads++; | |
1da177e4 LT |
1246 | } |
1247 | ||
1da177e4 | 1248 | total_forks++; |
3f17da69 | 1249 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1250 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1251 | proc_fork_connector(p); |
1da177e4 LT |
1252 | return p; |
1253 | ||
1254 | bad_fork_cleanup_namespace: | |
1255 | exit_namespace(p); | |
1256 | bad_fork_cleanup_keys: | |
1257 | exit_keys(p); | |
1258 | bad_fork_cleanup_mm: | |
1259 | if (p->mm) | |
1260 | mmput(p->mm); | |
1261 | bad_fork_cleanup_signal: | |
6b3934ef | 1262 | cleanup_signal(p); |
1da177e4 | 1263 | bad_fork_cleanup_sighand: |
a7e5328a | 1264 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1265 | bad_fork_cleanup_fs: |
1266 | exit_fs(p); /* blocking */ | |
1267 | bad_fork_cleanup_files: | |
1268 | exit_files(p); /* blocking */ | |
1269 | bad_fork_cleanup_semundo: | |
1270 | exit_sem(p); | |
1271 | bad_fork_cleanup_audit: | |
1272 | audit_free(p); | |
1273 | bad_fork_cleanup_security: | |
1274 | security_task_free(p); | |
1275 | bad_fork_cleanup_policy: | |
1276 | #ifdef CONFIG_NUMA | |
1277 | mpol_free(p->mempolicy); | |
b4b26418 | 1278 | bad_fork_cleanup_cpuset: |
1da177e4 | 1279 | #endif |
b4b26418 | 1280 | cpuset_exit(p); |
35df17c5 SN |
1281 | bad_fork_cleanup_delays_binfmt: |
1282 | delayacct_tsk_free(p); | |
1da177e4 LT |
1283 | if (p->binfmt) |
1284 | module_put(p->binfmt->module); | |
1285 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1286 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1287 | bad_fork_cleanup_count: |
1288 | put_group_info(p->group_info); | |
1289 | atomic_dec(&p->user->processes); | |
1290 | free_uid(p->user); | |
1291 | bad_fork_free: | |
1292 | free_task(p); | |
fe7d37d1 ON |
1293 | fork_out: |
1294 | return ERR_PTR(retval); | |
1da177e4 LT |
1295 | } |
1296 | ||
1297 | struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs) | |
1298 | { | |
1299 | memset(regs, 0, sizeof(struct pt_regs)); | |
1300 | return regs; | |
1301 | } | |
1302 | ||
36c8b586 | 1303 | struct task_struct * __devinit fork_idle(int cpu) |
1da177e4 | 1304 | { |
36c8b586 | 1305 | struct task_struct *task; |
1da177e4 LT |
1306 | struct pt_regs regs; |
1307 | ||
1308 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0); | |
1309 | if (!task) | |
1310 | return ERR_PTR(-ENOMEM); | |
1311 | init_idle(task, cpu); | |
73b9ebfe | 1312 | |
1da177e4 LT |
1313 | return task; |
1314 | } | |
1315 | ||
1316 | static inline int fork_traceflag (unsigned clone_flags) | |
1317 | { | |
1318 | if (clone_flags & CLONE_UNTRACED) | |
1319 | return 0; | |
1320 | else if (clone_flags & CLONE_VFORK) { | |
1321 | if (current->ptrace & PT_TRACE_VFORK) | |
1322 | return PTRACE_EVENT_VFORK; | |
1323 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1324 | if (current->ptrace & PT_TRACE_CLONE) | |
1325 | return PTRACE_EVENT_CLONE; | |
1326 | } else if (current->ptrace & PT_TRACE_FORK) | |
1327 | return PTRACE_EVENT_FORK; | |
1328 | ||
1329 | return 0; | |
1330 | } | |
1331 | ||
1332 | /* | |
1333 | * Ok, this is the main fork-routine. | |
1334 | * | |
1335 | * It copies the process, and if successful kick-starts | |
1336 | * it and waits for it to finish using the VM if required. | |
1337 | */ | |
1338 | long do_fork(unsigned long clone_flags, | |
1339 | unsigned long stack_start, | |
1340 | struct pt_regs *regs, | |
1341 | unsigned long stack_size, | |
1342 | int __user *parent_tidptr, | |
1343 | int __user *child_tidptr) | |
1344 | { | |
1345 | struct task_struct *p; | |
1346 | int trace = 0; | |
92476d7f EB |
1347 | struct pid *pid = alloc_pid(); |
1348 | long nr; | |
1da177e4 | 1349 | |
92476d7f | 1350 | if (!pid) |
1da177e4 | 1351 | return -EAGAIN; |
92476d7f | 1352 | nr = pid->nr; |
1da177e4 LT |
1353 | if (unlikely(current->ptrace)) { |
1354 | trace = fork_traceflag (clone_flags); | |
1355 | if (trace) | |
1356 | clone_flags |= CLONE_PTRACE; | |
1357 | } | |
1358 | ||
92476d7f | 1359 | p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, nr); |
1da177e4 LT |
1360 | /* |
1361 | * Do this prior waking up the new thread - the thread pointer | |
1362 | * might get invalid after that point, if the thread exits quickly. | |
1363 | */ | |
1364 | if (!IS_ERR(p)) { | |
1365 | struct completion vfork; | |
1366 | ||
1367 | if (clone_flags & CLONE_VFORK) { | |
1368 | p->vfork_done = &vfork; | |
1369 | init_completion(&vfork); | |
1370 | } | |
1371 | ||
1372 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1373 | /* | |
1374 | * We'll start up with an immediate SIGSTOP. | |
1375 | */ | |
1376 | sigaddset(&p->pending.signal, SIGSTOP); | |
1377 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1378 | } | |
1379 | ||
1380 | if (!(clone_flags & CLONE_STOPPED)) | |
1381 | wake_up_new_task(p, clone_flags); | |
1382 | else | |
1383 | p->state = TASK_STOPPED; | |
1384 | ||
1385 | if (unlikely (trace)) { | |
92476d7f | 1386 | current->ptrace_message = nr; |
1da177e4 LT |
1387 | ptrace_notify ((trace << 8) | SIGTRAP); |
1388 | } | |
1389 | ||
1390 | if (clone_flags & CLONE_VFORK) { | |
1391 | wait_for_completion(&vfork); | |
9f59ce5d CE |
1392 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) { |
1393 | current->ptrace_message = nr; | |
1da177e4 | 1394 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); |
9f59ce5d | 1395 | } |
1da177e4 LT |
1396 | } |
1397 | } else { | |
92476d7f EB |
1398 | free_pid(pid); |
1399 | nr = PTR_ERR(p); | |
1da177e4 | 1400 | } |
92476d7f | 1401 | return nr; |
1da177e4 LT |
1402 | } |
1403 | ||
5fd63b30 RT |
1404 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1405 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1406 | #endif | |
1407 | ||
aa1757f9 ON |
1408 | static void sighand_ctor(void *data, kmem_cache_t *cachep, unsigned long flags) |
1409 | { | |
1410 | struct sighand_struct *sighand = data; | |
1411 | ||
1412 | if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == | |
1413 | SLAB_CTOR_CONSTRUCTOR) | |
1414 | spin_lock_init(&sighand->siglock); | |
1415 | } | |
1416 | ||
1da177e4 LT |
1417 | void __init proc_caches_init(void) |
1418 | { | |
1419 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1420 | sizeof(struct sighand_struct), 0, | |
aa1757f9 ON |
1421 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
1422 | sighand_ctor, NULL); | |
1da177e4 LT |
1423 | signal_cachep = kmem_cache_create("signal_cache", |
1424 | sizeof(struct signal_struct), 0, | |
1425 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1426 | files_cachep = kmem_cache_create("files_cache", | |
1427 | sizeof(struct files_struct), 0, | |
1428 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1429 | fs_cachep = kmem_cache_create("fs_cache", | |
1430 | sizeof(struct fs_struct), 0, | |
1431 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); | |
1432 | vm_area_cachep = kmem_cache_create("vm_area_struct", | |
1433 | sizeof(struct vm_area_struct), 0, | |
1434 | SLAB_PANIC, NULL, NULL); | |
1435 | mm_cachep = kmem_cache_create("mm_struct", | |
5fd63b30 | 1436 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
1da177e4 LT |
1437 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
1438 | } | |
cf2e340f JD |
1439 | |
1440 | ||
1441 | /* | |
1442 | * Check constraints on flags passed to the unshare system call and | |
1443 | * force unsharing of additional process context as appropriate. | |
1444 | */ | |
1445 | static inline void check_unshare_flags(unsigned long *flags_ptr) | |
1446 | { | |
1447 | /* | |
1448 | * If unsharing a thread from a thread group, must also | |
1449 | * unshare vm. | |
1450 | */ | |
1451 | if (*flags_ptr & CLONE_THREAD) | |
1452 | *flags_ptr |= CLONE_VM; | |
1453 | ||
1454 | /* | |
1455 | * If unsharing vm, must also unshare signal handlers. | |
1456 | */ | |
1457 | if (*flags_ptr & CLONE_VM) | |
1458 | *flags_ptr |= CLONE_SIGHAND; | |
1459 | ||
1460 | /* | |
1461 | * If unsharing signal handlers and the task was created | |
1462 | * using CLONE_THREAD, then must unshare the thread | |
1463 | */ | |
1464 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1465 | (atomic_read(¤t->signal->count) > 1)) | |
1466 | *flags_ptr |= CLONE_THREAD; | |
1467 | ||
1468 | /* | |
1469 | * If unsharing namespace, must also unshare filesystem information. | |
1470 | */ | |
1471 | if (*flags_ptr & CLONE_NEWNS) | |
1472 | *flags_ptr |= CLONE_FS; | |
1473 | } | |
1474 | ||
1475 | /* | |
1476 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1477 | */ | |
1478 | static int unshare_thread(unsigned long unshare_flags) | |
1479 | { | |
1480 | if (unshare_flags & CLONE_THREAD) | |
1481 | return -EINVAL; | |
1482 | ||
1483 | return 0; | |
1484 | } | |
1485 | ||
1486 | /* | |
99d1419d | 1487 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1488 | */ |
1489 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1490 | { | |
1491 | struct fs_struct *fs = current->fs; | |
1492 | ||
1493 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1494 | (fs && atomic_read(&fs->count) > 1)) { |
1495 | *new_fsp = __copy_fs_struct(current->fs); | |
1496 | if (!*new_fsp) | |
1497 | return -ENOMEM; | |
1498 | } | |
cf2e340f JD |
1499 | |
1500 | return 0; | |
1501 | } | |
1502 | ||
1503 | /* | |
741a2951 | 1504 | * Unshare the namespace structure if it is being shared |
cf2e340f | 1505 | */ |
741a2951 | 1506 | static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs) |
cf2e340f JD |
1507 | { |
1508 | struct namespace *ns = current->namespace; | |
1509 | ||
1510 | if ((unshare_flags & CLONE_NEWNS) && | |
741a2951 JD |
1511 | (ns && atomic_read(&ns->count) > 1)) { |
1512 | if (!capable(CAP_SYS_ADMIN)) | |
1513 | return -EPERM; | |
1514 | ||
1515 | *new_nsp = dup_namespace(current, new_fs ? new_fs : current->fs); | |
1516 | if (!*new_nsp) | |
1517 | return -ENOMEM; | |
1518 | } | |
cf2e340f JD |
1519 | |
1520 | return 0; | |
1521 | } | |
1522 | ||
1523 | /* | |
1524 | * Unsharing of sighand for tasks created with CLONE_SIGHAND is not | |
1525 | * supported yet | |
1526 | */ | |
1527 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1528 | { | |
1529 | struct sighand_struct *sigh = current->sighand; | |
1530 | ||
1531 | if ((unshare_flags & CLONE_SIGHAND) && | |
1532 | (sigh && atomic_read(&sigh->count) > 1)) | |
1533 | return -EINVAL; | |
1534 | else | |
1535 | return 0; | |
1536 | } | |
1537 | ||
1538 | /* | |
a0a7ec30 | 1539 | * Unshare vm if it is being shared |
cf2e340f JD |
1540 | */ |
1541 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1542 | { | |
1543 | struct mm_struct *mm = current->mm; | |
1544 | ||
1545 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1546 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1547 | return -EINVAL; |
a0a7ec30 | 1548 | } |
cf2e340f JD |
1549 | |
1550 | return 0; | |
cf2e340f JD |
1551 | } |
1552 | ||
1553 | /* | |
a016f338 | 1554 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1555 | */ |
1556 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1557 | { | |
1558 | struct files_struct *fd = current->files; | |
a016f338 | 1559 | int error = 0; |
cf2e340f JD |
1560 | |
1561 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1562 | (fd && atomic_read(&fd->count) > 1)) { |
1563 | *new_fdp = dup_fd(fd, &error); | |
1564 | if (!*new_fdp) | |
1565 | return error; | |
1566 | } | |
cf2e340f JD |
1567 | |
1568 | return 0; | |
1569 | } | |
1570 | ||
1571 | /* | |
1572 | * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not | |
1573 | * supported yet | |
1574 | */ | |
1575 | static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp) | |
1576 | { | |
1577 | if (unshare_flags & CLONE_SYSVSEM) | |
1578 | return -EINVAL; | |
1579 | ||
1580 | return 0; | |
1581 | } | |
1582 | ||
1583 | /* | |
1584 | * unshare allows a process to 'unshare' part of the process | |
1585 | * context which was originally shared using clone. copy_* | |
1586 | * functions used by do_fork() cannot be used here directly | |
1587 | * because they modify an inactive task_struct that is being | |
1588 | * constructed. Here we are modifying the current, active, | |
1589 | * task_struct. | |
1590 | */ | |
1591 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1592 | { | |
1593 | int err = 0; | |
1594 | struct fs_struct *fs, *new_fs = NULL; | |
1595 | struct namespace *ns, *new_ns = NULL; | |
1596 | struct sighand_struct *sigh, *new_sigh = NULL; | |
1597 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; | |
1598 | struct files_struct *fd, *new_fd = NULL; | |
1599 | struct sem_undo_list *new_ulist = NULL; | |
1600 | ||
1601 | check_unshare_flags(&unshare_flags); | |
1602 | ||
06f9d4f9 EB |
1603 | /* Return -EINVAL for all unsupported flags */ |
1604 | err = -EINVAL; | |
1605 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
1606 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM)) | |
1607 | goto bad_unshare_out; | |
1608 | ||
cf2e340f JD |
1609 | if ((err = unshare_thread(unshare_flags))) |
1610 | goto bad_unshare_out; | |
1611 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1612 | goto bad_unshare_cleanup_thread; | |
741a2951 | 1613 | if ((err = unshare_namespace(unshare_flags, &new_ns, new_fs))) |
cf2e340f JD |
1614 | goto bad_unshare_cleanup_fs; |
1615 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) | |
1616 | goto bad_unshare_cleanup_ns; | |
1617 | if ((err = unshare_vm(unshare_flags, &new_mm))) | |
1618 | goto bad_unshare_cleanup_sigh; | |
1619 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1620 | goto bad_unshare_cleanup_vm; | |
1621 | if ((err = unshare_semundo(unshare_flags, &new_ulist))) | |
1622 | goto bad_unshare_cleanup_fd; | |
1623 | ||
1624 | if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) { | |
1625 | ||
1626 | task_lock(current); | |
1627 | ||
1628 | if (new_fs) { | |
1629 | fs = current->fs; | |
1630 | current->fs = new_fs; | |
1631 | new_fs = fs; | |
1632 | } | |
1633 | ||
1634 | if (new_ns) { | |
1635 | ns = current->namespace; | |
1636 | current->namespace = new_ns; | |
1637 | new_ns = ns; | |
1638 | } | |
1639 | ||
1640 | if (new_sigh) { | |
1641 | sigh = current->sighand; | |
e0e8eb54 | 1642 | rcu_assign_pointer(current->sighand, new_sigh); |
cf2e340f JD |
1643 | new_sigh = sigh; |
1644 | } | |
1645 | ||
1646 | if (new_mm) { | |
1647 | mm = current->mm; | |
1648 | active_mm = current->active_mm; | |
1649 | current->mm = new_mm; | |
1650 | current->active_mm = new_mm; | |
1651 | activate_mm(active_mm, new_mm); | |
1652 | new_mm = mm; | |
1653 | } | |
1654 | ||
1655 | if (new_fd) { | |
1656 | fd = current->files; | |
1657 | current->files = new_fd; | |
1658 | new_fd = fd; | |
1659 | } | |
1660 | ||
1661 | task_unlock(current); | |
1662 | } | |
1663 | ||
1664 | bad_unshare_cleanup_fd: | |
1665 | if (new_fd) | |
1666 | put_files_struct(new_fd); | |
1667 | ||
1668 | bad_unshare_cleanup_vm: | |
1669 | if (new_mm) | |
1670 | mmput(new_mm); | |
1671 | ||
1672 | bad_unshare_cleanup_sigh: | |
1673 | if (new_sigh) | |
1674 | if (atomic_dec_and_test(&new_sigh->count)) | |
1675 | kmem_cache_free(sighand_cachep, new_sigh); | |
1676 | ||
1677 | bad_unshare_cleanup_ns: | |
1678 | if (new_ns) | |
1679 | put_namespace(new_ns); | |
1680 | ||
1681 | bad_unshare_cleanup_fs: | |
1682 | if (new_fs) | |
1683 | put_fs_struct(new_fs); | |
1684 | ||
1685 | bad_unshare_cleanup_thread: | |
1686 | bad_unshare_out: | |
1687 | return err; | |
1688 | } |