blob: dfd10cb370c388119685a5983511b5ad60c74191 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/fork.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7/*
8 * 'fork.c' contains the help-routines for the 'fork' system call
9 * (see also entry.S and others).
10 * Fork is rather simple, once you get the hang of it, but the memory
11 * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
12 */
13
14#include <linux/config.h>
15#include <linux/slab.h>
16#include <linux/init.h>
17#include <linux/unistd.h>
18#include <linux/smp_lock.h>
19#include <linux/module.h>
20#include <linux/vmalloc.h>
21#include <linux/completion.h>
22#include <linux/namespace.h>
23#include <linux/personality.h>
24#include <linux/mempolicy.h>
25#include <linux/sem.h>
26#include <linux/file.h>
27#include <linux/key.h>
28#include <linux/binfmts.h>
29#include <linux/mman.h>
30#include <linux/fs.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080031#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/cpu.h>
33#include <linux/cpuset.h>
34#include <linux/security.h>
35#include <linux/swap.h>
36#include <linux/syscalls.h>
37#include <linux/jiffies.h>
38#include <linux/futex.h>
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070039#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <linux/ptrace.h>
41#include <linux/mount.h>
42#include <linux/audit.h>
43#include <linux/profile.h>
44#include <linux/rmap.h>
45#include <linux/acct.h>
Matt Helsley9f460802005-11-07 00:59:16 -080046#include <linux/cn_proc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48#include <asm/pgtable.h>
49#include <asm/pgalloc.h>
50#include <asm/uaccess.h>
51#include <asm/mmu_context.h>
52#include <asm/cacheflush.h>
53#include <asm/tlbflush.h>
54
55/*
56 * Protected counters by write_lock_irq(&tasklist_lock)
57 */
58unsigned long total_forks; /* Handle normal Linux uptimes. */
59int nr_threads; /* The idle threads do not count.. */
60
61int max_threads; /* tunable limit on nr_threads */
62
63DEFINE_PER_CPU(unsigned long, process_counts) = 0;
64
65 __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
66
67EXPORT_SYMBOL(tasklist_lock);
68
69int nr_processes(void)
70{
71 int cpu;
72 int total = 0;
73
74 for_each_online_cpu(cpu)
75 total += per_cpu(process_counts, cpu);
76
77 return total;
78}
79
80#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
81# define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
82# define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk))
83static kmem_cache_t *task_struct_cachep;
84#endif
85
86/* SLAB cache for signal_struct structures (tsk->signal) */
Oleg Nesterov6b3934ef2006-03-28 16:11:16 -080087static kmem_cache_t *signal_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89/* SLAB cache for sighand_struct structures (tsk->sighand) */
90kmem_cache_t *sighand_cachep;
91
92/* SLAB cache for files_struct structures (tsk->files) */
93kmem_cache_t *files_cachep;
94
95/* SLAB cache for fs_struct structures (tsk->fs) */
96kmem_cache_t *fs_cachep;
97
98/* SLAB cache for vm_area_struct structures */
99kmem_cache_t *vm_area_cachep;
100
101/* SLAB cache for mm_struct structures (tsk->mm) */
102static kmem_cache_t *mm_cachep;
103
104void free_task(struct task_struct *tsk)
105{
106 free_thread_info(tsk->thread_info);
107 free_task_struct(tsk);
108}
109EXPORT_SYMBOL(free_task);
110
Andrew Morton158d9eb2006-03-31 02:31:34 -0800111void __put_task_struct(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112{
113 WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)));
114 WARN_ON(atomic_read(&tsk->usage));
115 WARN_ON(tsk == current);
116
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 security_task_free(tsk);
118 free_uid(tsk->user);
119 put_group_info(tsk->group_info);
120
121 if (!profile_handoff_task(tsk))
122 free_task(tsk);
123}
124
125void __init fork_init(unsigned long mempages)
126{
127#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
128#ifndef ARCH_MIN_TASKALIGN
129#define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
130#endif
131 /* create a slab on which task_structs can be allocated */
132 task_struct_cachep =
133 kmem_cache_create("task_struct", sizeof(struct task_struct),
134 ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL);
135#endif
136
137 /*
138 * The default maximum number of threads is set to a safe
139 * value: the thread structures can take up at most half
140 * of memory.
141 */
142 max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE);
143
144 /*
145 * we need to allow at least 20 threads to boot a system
146 */
147 if(max_threads < 20)
148 max_threads = 20;
149
150 init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
151 init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
152 init_task.signal->rlim[RLIMIT_SIGPENDING] =
153 init_task.signal->rlim[RLIMIT_NPROC];
154}
155
156static struct task_struct *dup_task_struct(struct task_struct *orig)
157{
158 struct task_struct *tsk;
159 struct thread_info *ti;
160
161 prepare_to_copy(orig);
162
163 tsk = alloc_task_struct();
164 if (!tsk)
165 return NULL;
166
167 ti = alloc_thread_info(tsk);
168 if (!ti) {
169 free_task_struct(tsk);
170 return NULL;
171 }
172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 *tsk = *orig;
174 tsk->thread_info = ti;
Al Viro10ebffd2005-11-13 16:06:56 -0800175 setup_thread_stack(tsk, orig);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
177 /* One for us, one for whoever does the "release_task()" (usually parent) */
178 atomic_set(&tsk->usage,2);
Giancarlo Formicuccia4b5d37a2005-09-09 13:01:22 -0700179 atomic_set(&tsk->fs_excl, 0);
Jens Axboe2056a782006-03-23 20:00:26 +0100180 tsk->btrace_seq = 0;
Jens Axboea0aa7f62006-04-20 13:05:33 +0200181 tsk->splice_pipe = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 return tsk;
183}
184
185#ifdef CONFIG_MMU
Hugh Dickinsfd3e42f2005-10-29 18:16:06 -0700186static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187{
Hugh Dickinsfd3e42f2005-10-29 18:16:06 -0700188 struct vm_area_struct *mpnt, *tmp, **pprev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 struct rb_node **rb_link, *rb_parent;
190 int retval;
191 unsigned long charge;
192 struct mempolicy *pol;
193
194 down_write(&oldmm->mmap_sem);
Hugh Dickinsfd3e42f2005-10-29 18:16:06 -0700195 flush_cache_mm(oldmm);
Hugh Dickins7ee78232005-10-29 18:16:08 -0700196 down_write(&mm->mmap_sem);
197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 mm->locked_vm = 0;
199 mm->mmap = NULL;
200 mm->mmap_cache = NULL;
201 mm->free_area_cache = oldmm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700202 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 mm->map_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 cpus_clear(mm->cpu_vm_mask);
205 mm->mm_rb = RB_ROOT;
206 rb_link = &mm->mm_rb.rb_node;
207 rb_parent = NULL;
208 pprev = &mm->mmap;
209
Hugh Dickinsfd3e42f2005-10-29 18:16:06 -0700210 for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 struct file *file;
212
213 if (mpnt->vm_flags & VM_DONTCOPY) {
Hugh Dickins3b6bfcd2005-07-12 13:58:09 -0700214 long pages = vma_pages(mpnt);
215 mm->total_vm -= pages;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700216 vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file,
Hugh Dickins3b6bfcd2005-07-12 13:58:09 -0700217 -pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 continue;
219 }
220 charge = 0;
221 if (mpnt->vm_flags & VM_ACCOUNT) {
222 unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
223 if (security_vm_enough_memory(len))
224 goto fail_nomem;
225 charge = len;
226 }
227 tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
228 if (!tmp)
229 goto fail_nomem;
230 *tmp = *mpnt;
231 pol = mpol_copy(vma_policy(mpnt));
232 retval = PTR_ERR(pol);
233 if (IS_ERR(pol))
234 goto fail_nomem_policy;
235 vma_set_policy(tmp, pol);
236 tmp->vm_flags &= ~VM_LOCKED;
237 tmp->vm_mm = mm;
238 tmp->vm_next = NULL;
239 anon_vma_link(tmp);
240 file = tmp->vm_file;
241 if (file) {
242 struct inode *inode = file->f_dentry->d_inode;
243 get_file(file);
244 if (tmp->vm_flags & VM_DENYWRITE)
245 atomic_dec(&inode->i_writecount);
246
247 /* insert tmp into the share list, just after mpnt */
248 spin_lock(&file->f_mapping->i_mmap_lock);
249 tmp->vm_truncate_count = mpnt->vm_truncate_count;
250 flush_dcache_mmap_lock(file->f_mapping);
251 vma_prio_tree_add(tmp, mpnt);
252 flush_dcache_mmap_unlock(file->f_mapping);
253 spin_unlock(&file->f_mapping->i_mmap_lock);
254 }
255
256 /*
Hugh Dickins7ee78232005-10-29 18:16:08 -0700257 * Link in the new vma and copy the page table entries.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 *pprev = tmp;
260 pprev = &tmp->vm_next;
261
262 __vma_link_rb(mm, tmp, rb_link, rb_parent);
263 rb_link = &tmp->vm_rb.rb_right;
264 rb_parent = &tmp->vm_rb;
265
266 mm->map_count++;
Hugh Dickins0b0db142005-11-21 21:32:20 -0800267 retval = copy_page_range(mm, oldmm, mpnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
269 if (tmp->vm_ops && tmp->vm_ops->open)
270 tmp->vm_ops->open(tmp);
271
272 if (retval)
273 goto out;
274 }
275 retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276out:
Hugh Dickins7ee78232005-10-29 18:16:08 -0700277 up_write(&mm->mmap_sem);
Hugh Dickinsfd3e42f2005-10-29 18:16:06 -0700278 flush_tlb_mm(oldmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 up_write(&oldmm->mmap_sem);
280 return retval;
281fail_nomem_policy:
282 kmem_cache_free(vm_area_cachep, tmp);
283fail_nomem:
284 retval = -ENOMEM;
285 vm_unacct_memory(charge);
286 goto out;
287}
288
289static inline int mm_alloc_pgd(struct mm_struct * mm)
290{
291 mm->pgd = pgd_alloc(mm);
292 if (unlikely(!mm->pgd))
293 return -ENOMEM;
294 return 0;
295}
296
297static inline void mm_free_pgd(struct mm_struct * mm)
298{
299 pgd_free(mm->pgd);
300}
301#else
302#define dup_mmap(mm, oldmm) (0)
303#define mm_alloc_pgd(mm) (0)
304#define mm_free_pgd(mm)
305#endif /* CONFIG_MMU */
306
307 __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
308
309#define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL))
310#define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
311
312#include <linux/init_task.h>
313
314static struct mm_struct * mm_init(struct mm_struct * mm)
315{
316 atomic_set(&mm->mm_users, 1);
317 atomic_set(&mm->mm_count, 1);
318 init_rwsem(&mm->mmap_sem);
319 INIT_LIST_HEAD(&mm->mmlist);
320 mm->core_waiters = 0;
321 mm->nr_ptes = 0;
Hugh Dickins42946212005-10-29 18:16:05 -0700322 set_mm_counter(mm, file_rss, 0);
Hugh Dickins404351e2005-10-29 18:16:04 -0700323 set_mm_counter(mm, anon_rss, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 spin_lock_init(&mm->page_table_lock);
325 rwlock_init(&mm->ioctx_list_lock);
326 mm->ioctx_list = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 mm->free_area_cache = TASK_UNMAPPED_BASE;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700328 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
330 if (likely(!mm_alloc_pgd(mm))) {
331 mm->def_flags = 0;
332 return mm;
333 }
334 free_mm(mm);
335 return NULL;
336}
337
338/*
339 * Allocate and initialize an mm_struct.
340 */
341struct mm_struct * mm_alloc(void)
342{
343 struct mm_struct * mm;
344
345 mm = allocate_mm();
346 if (mm) {
347 memset(mm, 0, sizeof(*mm));
348 mm = mm_init(mm);
349 }
350 return mm;
351}
352
353/*
354 * Called when the last reference to the mm
355 * is dropped: either by a lazy thread or by
356 * mmput. Free the page directory and the mm.
357 */
358void fastcall __mmdrop(struct mm_struct *mm)
359{
360 BUG_ON(mm == &init_mm);
361 mm_free_pgd(mm);
362 destroy_context(mm);
363 free_mm(mm);
364}
365
366/*
367 * Decrement the use count and release all resources for an mm.
368 */
369void mmput(struct mm_struct *mm)
370{
Andrew Morton0ae26f12006-06-23 02:05:15 -0700371 might_sleep();
372
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 if (atomic_dec_and_test(&mm->mm_users)) {
374 exit_aio(mm);
375 exit_mmap(mm);
376 if (!list_empty(&mm->mmlist)) {
377 spin_lock(&mmlist_lock);
378 list_del(&mm->mmlist);
379 spin_unlock(&mmlist_lock);
380 }
381 put_swap_token(mm);
382 mmdrop(mm);
383 }
384}
385EXPORT_SYMBOL_GPL(mmput);
386
387/**
388 * get_task_mm - acquire a reference to the task's mm
389 *
390 * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning
391 * this kernel workthread has transiently adopted a user mm with use_mm,
392 * to do its AIO) is not set and if so returns a reference to it, after
393 * bumping up the use count. User must release the mm via mmput()
394 * after use. Typically used by /proc and ptrace.
395 */
396struct mm_struct *get_task_mm(struct task_struct *task)
397{
398 struct mm_struct *mm;
399
400 task_lock(task);
401 mm = task->mm;
402 if (mm) {
403 if (task->flags & PF_BORROWED_MM)
404 mm = NULL;
405 else
406 atomic_inc(&mm->mm_users);
407 }
408 task_unlock(task);
409 return mm;
410}
411EXPORT_SYMBOL_GPL(get_task_mm);
412
413/* Please note the differences between mmput and mm_release.
414 * mmput is called whenever we stop holding onto a mm_struct,
415 * error success whatever.
416 *
417 * mm_release is called after a mm_struct has been removed
418 * from the current process.
419 *
420 * This difference is important for error handling, when we
421 * only half set up a mm_struct for a new process and need to restore
422 * the old one. Because we mmput the new mm_struct before
423 * restoring the old one. . .
424 * Eric Biederman 10 January 1998
425 */
426void mm_release(struct task_struct *tsk, struct mm_struct *mm)
427{
428 struct completion *vfork_done = tsk->vfork_done;
429
430 /* Get rid of any cached register state */
431 deactivate_mm(tsk, mm);
432
433 /* notify parent sleeping on vfork() */
434 if (vfork_done) {
435 tsk->vfork_done = NULL;
436 complete(vfork_done);
437 }
438 if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) {
439 u32 __user * tidptr = tsk->clear_child_tid;
440 tsk->clear_child_tid = NULL;
441
442 /*
443 * We don't check the error code - if userspace has
444 * not set up a proper pointer then tough luck.
445 */
446 put_user(0, tidptr);
447 sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0);
448 }
449}
450
JANAK DESAIa0a7ec32006-02-07 12:59:01 -0800451/*
452 * Allocate a new mm structure and copy contents from the
453 * mm structure of the passed in task structure.
454 */
455static struct mm_struct *dup_mm(struct task_struct *tsk)
456{
457 struct mm_struct *mm, *oldmm = current->mm;
458 int err;
459
460 if (!oldmm)
461 return NULL;
462
463 mm = allocate_mm();
464 if (!mm)
465 goto fail_nomem;
466
467 memcpy(mm, oldmm, sizeof(*mm));
468
469 if (!mm_init(mm))
470 goto fail_nomem;
471
472 if (init_new_context(tsk, mm))
473 goto fail_nocontext;
474
475 err = dup_mmap(mm, oldmm);
476 if (err)
477 goto free_pt;
478
479 mm->hiwater_rss = get_mm_rss(mm);
480 mm->hiwater_vm = mm->total_vm;
481
482 return mm;
483
484free_pt:
485 mmput(mm);
486
487fail_nomem:
488 return NULL;
489
490fail_nocontext:
491 /*
492 * If init_new_context() failed, we cannot use mmput() to free the mm
493 * because it calls destroy_context()
494 */
495 mm_free_pgd(mm);
496 free_mm(mm);
497 return NULL;
498}
499
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
501{
502 struct mm_struct * mm, *oldmm;
503 int retval;
504
505 tsk->min_flt = tsk->maj_flt = 0;
506 tsk->nvcsw = tsk->nivcsw = 0;
507
508 tsk->mm = NULL;
509 tsk->active_mm = NULL;
510
511 /*
512 * Are we cloning a kernel thread?
513 *
514 * We need to steal a active VM for that..
515 */
516 oldmm = current->mm;
517 if (!oldmm)
518 return 0;
519
520 if (clone_flags & CLONE_VM) {
521 atomic_inc(&oldmm->mm_users);
522 mm = oldmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 goto good_mm;
524 }
525
526 retval = -ENOMEM;
JANAK DESAIa0a7ec32006-02-07 12:59:01 -0800527 mm = dup_mm(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 if (!mm)
529 goto fail_nomem;
530
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531good_mm:
532 tsk->mm = mm;
533 tsk->active_mm = mm;
534 return 0;
535
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536fail_nomem:
537 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538}
539
540static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
541{
542 struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
543 /* We don't need to lock fs - think why ;-) */
544 if (fs) {
545 atomic_set(&fs->count, 1);
546 rwlock_init(&fs->lock);
547 fs->umask = old->umask;
548 read_lock(&old->lock);
549 fs->rootmnt = mntget(old->rootmnt);
550 fs->root = dget(old->root);
551 fs->pwdmnt = mntget(old->pwdmnt);
552 fs->pwd = dget(old->pwd);
553 if (old->altroot) {
554 fs->altrootmnt = mntget(old->altrootmnt);
555 fs->altroot = dget(old->altroot);
556 } else {
557 fs->altrootmnt = NULL;
558 fs->altroot = NULL;
559 }
560 read_unlock(&old->lock);
561 }
562 return fs;
563}
564
565struct fs_struct *copy_fs_struct(struct fs_struct *old)
566{
567 return __copy_fs_struct(old);
568}
569
570EXPORT_SYMBOL_GPL(copy_fs_struct);
571
572static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
573{
574 if (clone_flags & CLONE_FS) {
575 atomic_inc(&current->fs->count);
576 return 0;
577 }
578 tsk->fs = __copy_fs_struct(current->fs);
579 if (!tsk->fs)
580 return -ENOMEM;
581 return 0;
582}
583
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700584static int count_open_files(struct fdtable *fdt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585{
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700586 int size = fdt->max_fdset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 int i;
588
589 /* Find the last open fd */
590 for (i = size/(8*sizeof(long)); i > 0; ) {
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700591 if (fdt->open_fds->fds_bits[--i])
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 break;
593 }
594 i = (i+1) * 8 * sizeof(long);
595 return i;
596}
597
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700598static struct files_struct *alloc_files(void)
599{
600 struct files_struct *newf;
601 struct fdtable *fdt;
602
603 newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL);
604 if (!newf)
605 goto out;
606
607 atomic_set(&newf->count, 1);
608
609 spin_lock_init(&newf->file_lock);
Eric Dumazet0c9e63f2006-03-23 03:00:12 -0800610 newf->next_fd = 0;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700611 fdt = &newf->fdtab;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700612 fdt->max_fds = NR_OPEN_DEFAULT;
Eric Dumazet0c9e63f2006-03-23 03:00:12 -0800613 fdt->max_fdset = EMBEDDED_FD_SET_SIZE;
614 fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init;
615 fdt->open_fds = (fd_set *)&newf->open_fds_init;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700616 fdt->fd = &newf->fd_array[0];
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700617 INIT_RCU_HEAD(&fdt->rcu);
618 fdt->free_files = NULL;
619 fdt->next = NULL;
620 rcu_assign_pointer(newf->fdt, fdt);
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700621out:
622 return newf;
623}
624
JANAK DESAIa016f332006-02-07 12:59:02 -0800625/*
626 * Allocate a new files structure and copy contents from the
627 * passed in files structure.
Prasanna Meda6e667262006-06-23 02:05:23 -0700628 * errorp will be valid only when the returned files_struct is NULL.
JANAK DESAIa016f332006-02-07 12:59:02 -0800629 */
630static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631{
JANAK DESAIa016f332006-02-07 12:59:02 -0800632 struct files_struct *newf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 struct file **old_fds, **new_fds;
JANAK DESAIa016f332006-02-07 12:59:02 -0800634 int open_files, size, i, expand;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700635 struct fdtable *old_fdt, *new_fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636
Prasanna Meda6e667262006-06-23 02:05:23 -0700637 *errorp = -ENOMEM;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700638 newf = alloc_files();
639 if (!newf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 goto out;
641
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 spin_lock(&oldf->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700643 old_fdt = files_fdtable(oldf);
644 new_fdt = files_fdtable(newf);
645 size = old_fdt->max_fdset;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700646 open_files = count_open_files(old_fdt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 expand = 0;
648
649 /*
650 * Check whether we need to allocate a larger fd array or fd set.
651 * Note: we're not a clone task, so the open count won't change.
652 */
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700653 if (open_files > new_fdt->max_fdset) {
654 new_fdt->max_fdset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 expand = 1;
656 }
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700657 if (open_files > new_fdt->max_fds) {
658 new_fdt->max_fds = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 expand = 1;
660 }
661
662 /* if the old fdset gets grown now, we'll only copy up to "size" fds */
663 if (expand) {
664 spin_unlock(&oldf->file_lock);
665 spin_lock(&newf->file_lock);
JANAK DESAIa016f332006-02-07 12:59:02 -0800666 *errorp = expand_files(newf, open_files-1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 spin_unlock(&newf->file_lock);
JANAK DESAIa016f332006-02-07 12:59:02 -0800668 if (*errorp < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 goto out_release;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700670 new_fdt = files_fdtable(newf);
671 /*
672 * Reacquire the oldf lock and a pointer to its fd table
673 * who knows it may have a new bigger fd table. We need
674 * the latest pointer.
675 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 spin_lock(&oldf->file_lock);
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700677 old_fdt = files_fdtable(oldf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 }
679
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700680 old_fds = old_fdt->fd;
681 new_fds = new_fdt->fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700683 memcpy(new_fdt->open_fds->fds_bits, old_fdt->open_fds->fds_bits, open_files/8);
684 memcpy(new_fdt->close_on_exec->fds_bits, old_fdt->close_on_exec->fds_bits, open_files/8);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685
686 for (i = open_files; i != 0; i--) {
687 struct file *f = *old_fds++;
688 if (f) {
689 get_file(f);
690 } else {
691 /*
692 * The fd may be claimed in the fd bitmap but not yet
693 * instantiated in the files array if a sibling thread
694 * is partway through open(). So make sure that this
695 * fd is available to the new process.
696 */
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700697 FD_CLR(open_files - i, new_fdt->open_fds);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 }
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700699 rcu_assign_pointer(*new_fds++, f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 }
701 spin_unlock(&oldf->file_lock);
702
703 /* compute the remainder to be cleared */
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700704 size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705
706 /* This is long word aligned thus could use a optimized version */
707 memset(new_fds, 0, size);
708
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700709 if (new_fdt->max_fdset > open_files) {
710 int left = (new_fdt->max_fdset-open_files)/8;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 int start = open_files / (8 * sizeof(unsigned long));
712
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700713 memset(&new_fdt->open_fds->fds_bits[start], 0, left);
714 memset(&new_fdt->close_on_exec->fds_bits[start], 0, left);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 }
716
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717out:
JANAK DESAIa016f332006-02-07 12:59:02 -0800718 return newf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719
720out_release:
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700721 free_fdset (new_fdt->close_on_exec, new_fdt->max_fdset);
722 free_fdset (new_fdt->open_fds, new_fdt->max_fdset);
723 free_fd_array(new_fdt->fd, new_fdt->max_fds);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 kmem_cache_free(files_cachep, newf);
Kirill Korotaev42862292006-03-31 17:58:46 +0400725 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726}
727
JANAK DESAIa016f332006-02-07 12:59:02 -0800728static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
729{
730 struct files_struct *oldf, *newf;
731 int error = 0;
732
733 /*
734 * A background process may not have any files ...
735 */
736 oldf = current->files;
737 if (!oldf)
738 goto out;
739
740 if (clone_flags & CLONE_FILES) {
741 atomic_inc(&oldf->count);
742 goto out;
743 }
744
745 /*
746 * Note: we may be using current for both targets (See exec.c)
747 * This works because we cache current->files (old) as oldf. Don't
748 * break this.
749 */
750 tsk->files = NULL;
JANAK DESAIa016f332006-02-07 12:59:02 -0800751 newf = dup_fd(oldf, &error);
752 if (!newf)
753 goto out;
754
755 tsk->files = newf;
756 error = 0;
757out:
758 return error;
759}
760
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761/*
762 * Helper to unshare the files of the current task.
763 * We don't want to expose copy_files internals to
764 * the exec layer of the kernel.
765 */
766
767int unshare_files(void)
768{
769 struct files_struct *files = current->files;
770 int rc;
771
Eric Sesterhenn910dea72006-03-26 18:29:26 +0200772 BUG_ON(!files);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773
774 /* This can race but the race causes us to copy when we don't
775 need to and drop the copy */
776 if(atomic_read(&files->count) == 1)
777 {
778 atomic_inc(&files->count);
779 return 0;
780 }
781 rc = copy_files(0, current);
782 if(rc)
783 current->files = files;
784 return rc;
785}
786
787EXPORT_SYMBOL(unshare_files);
788
789static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
790{
791 struct sighand_struct *sig;
792
793 if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) {
794 atomic_inc(&current->sighand->count);
795 return 0;
796 }
797 sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
Ingo Molnare56d0902006-01-08 01:01:37 -0800798 rcu_assign_pointer(tsk->sighand, sig);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 if (!sig)
800 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 atomic_set(&sig->count, 1);
802 memcpy(sig->action, current->sighand->action, sizeof(sig->action));
803 return 0;
804}
805
Oleg Nesterova7e53282006-03-28 16:11:27 -0800806void __cleanup_sighand(struct sighand_struct *sighand)
Oleg Nesterovc81addc2006-03-28 16:11:17 -0800807{
Oleg Nesterovc81addc2006-03-28 16:11:17 -0800808 if (atomic_dec_and_test(&sighand->count))
809 kmem_cache_free(sighand_cachep, sighand);
810}
811
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk)
813{
814 struct signal_struct *sig;
815 int ret;
816
817 if (clone_flags & CLONE_THREAD) {
818 atomic_inc(&current->signal->count);
819 atomic_inc(&current->signal->live);
820 return 0;
821 }
822 sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
823 tsk->signal = sig;
824 if (!sig)
825 return -ENOMEM;
826
827 ret = copy_thread_group_keys(tsk);
828 if (ret < 0) {
829 kmem_cache_free(signal_cachep, sig);
830 return ret;
831 }
832
833 atomic_set(&sig->count, 1);
834 atomic_set(&sig->live, 1);
835 init_waitqueue_head(&sig->wait_chldexit);
836 sig->flags = 0;
837 sig->group_exit_code = 0;
838 sig->group_exit_task = NULL;
839 sig->group_stop_count = 0;
840 sig->curr_target = NULL;
841 init_sigpending(&sig->shared_pending);
842 INIT_LIST_HEAD(&sig->posix_timers);
843
George Anzinger7978672c2006-02-01 03:05:11 -0800844 hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL);
Thomas Gleixner2ff678b2006-01-09 20:52:34 -0800845 sig->it_real_incr.tv64 = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 sig->real_timer.function = it_real_fn;
Roman Zippel05cfb612006-03-26 01:38:12 -0800847 sig->tsk = tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848
849 sig->it_virt_expires = cputime_zero;
850 sig->it_virt_incr = cputime_zero;
851 sig->it_prof_expires = cputime_zero;
852 sig->it_prof_incr = cputime_zero;
853
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 sig->leader = 0; /* session leadership doesn't inherit */
855 sig->tty_old_pgrp = 0;
856
857 sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero;
858 sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0;
859 sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0;
860 sig->sched_time = 0;
861 INIT_LIST_HEAD(&sig->cpu_timers[0]);
862 INIT_LIST_HEAD(&sig->cpu_timers[1]);
863 INIT_LIST_HEAD(&sig->cpu_timers[2]);
864
865 task_lock(current->group_leader);
866 memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
867 task_unlock(current->group_leader);
868
869 if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
870 /*
871 * New sole thread in the process gets an expiry time
872 * of the whole CPU time limit.
873 */
874 tsk->it_prof_expires =
875 secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
876 }
KaiGai Kohei0e464812006-06-25 05:49:24 -0700877 acct_init_pacct(&sig->pacct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878
879 return 0;
880}
881
Oleg Nesterov6b3934ef2006-03-28 16:11:16 -0800882void __cleanup_signal(struct signal_struct *sig)
883{
884 exit_thread_group_keys(sig);
885 kmem_cache_free(signal_cachep, sig);
886}
887
888static inline void cleanup_signal(struct task_struct *tsk)
889{
890 struct signal_struct *sig = tsk->signal;
891
892 atomic_dec(&sig->live);
893
894 if (atomic_dec_and_test(&sig->count))
895 __cleanup_signal(sig);
896}
897
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
899{
900 unsigned long new_flags = p->flags;
901
Alan Sternd1209d02005-10-19 21:23:51 -0700902 new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 new_flags |= PF_FORKNOEXEC;
904 if (!(clone_flags & CLONE_PTRACE))
905 p->ptrace = 0;
906 p->flags = new_flags;
907}
908
909asmlinkage long sys_set_tid_address(int __user *tidptr)
910{
911 current->clear_child_tid = tidptr;
912
913 return current->pid;
914}
915
916/*
917 * This creates a new process as a copy of the old one,
918 * but does not actually start it yet.
919 *
920 * It copies the registers, and all the appropriate
921 * parts of the process environment (as per the clone
922 * flags). The actual kick-off is left to the caller.
923 */
924static task_t *copy_process(unsigned long clone_flags,
925 unsigned long stack_start,
926 struct pt_regs *regs,
927 unsigned long stack_size,
928 int __user *parent_tidptr,
929 int __user *child_tidptr,
930 int pid)
931{
932 int retval;
933 struct task_struct *p = NULL;
934
935 if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
936 return ERR_PTR(-EINVAL);
937
938 /*
939 * Thread groups must share signals as well, and detached threads
940 * can only be started up within the thread group.
941 */
942 if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
943 return ERR_PTR(-EINVAL);
944
945 /*
946 * Shared signal handlers imply shared VM. By way of the above,
947 * thread groups also imply shared VM. Blocking this case allows
948 * for various simplifications in other code.
949 */
950 if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
951 return ERR_PTR(-EINVAL);
952
953 retval = security_task_create(clone_flags);
954 if (retval)
955 goto fork_out;
956
957 retval = -ENOMEM;
958 p = dup_task_struct(current);
959 if (!p)
960 goto fork_out;
961
962 retval = -EAGAIN;
963 if (atomic_read(&p->user->processes) >=
964 p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
965 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
966 p->user != &root_user)
967 goto bad_fork_free;
968 }
969
970 atomic_inc(&p->user->__count);
971 atomic_inc(&p->user->processes);
972 get_group_info(p->group_info);
973
974 /*
975 * If multiple threads are within copy_process(), then this check
976 * triggers too late. This doesn't hurt, the check is only there
977 * to stop root fork bombs.
978 */
979 if (nr_threads >= max_threads)
980 goto bad_fork_cleanup_count;
981
Al Viroa1261f542005-11-13 16:06:55 -0800982 if (!try_module_get(task_thread_info(p)->exec_domain->module))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983 goto bad_fork_cleanup_count;
984
985 if (p->binfmt && !try_module_get(p->binfmt->module))
986 goto bad_fork_cleanup_put_domain;
987
988 p->did_exec = 0;
989 copy_flags(clone_flags, p);
990 p->pid = pid;
991 retval = -EFAULT;
992 if (clone_flags & CLONE_PARENT_SETTID)
993 if (put_user(p->pid, parent_tidptr))
994 goto bad_fork_cleanup;
995
996 p->proc_dentry = NULL;
997
998 INIT_LIST_HEAD(&p->children);
999 INIT_LIST_HEAD(&p->sibling);
1000 p->vfork_done = NULL;
1001 spin_lock_init(&p->alloc_lock);
1002 spin_lock_init(&p->proc_lock);
1003
1004 clear_tsk_thread_flag(p, TIF_SIGPENDING);
1005 init_sigpending(&p->pending);
1006
1007 p->utime = cputime_zero;
1008 p->stime = cputime_zero;
1009 p->sched_time = 0;
1010 p->rchar = 0; /* I/O counter: bytes read */
1011 p->wchar = 0; /* I/O counter: bytes written */
1012 p->syscr = 0; /* I/O counter: read syscalls */
1013 p->syscw = 0; /* I/O counter: write syscalls */
1014 acct_clear_integrals(p);
1015
1016 p->it_virt_expires = cputime_zero;
1017 p->it_prof_expires = cputime_zero;
1018 p->it_sched_expires = 0;
1019 INIT_LIST_HEAD(&p->cpu_timers[0]);
1020 INIT_LIST_HEAD(&p->cpu_timers[1]);
1021 INIT_LIST_HEAD(&p->cpu_timers[2]);
1022
1023 p->lock_depth = -1; /* -1 = no lock */
1024 do_posix_clock_monotonic_gettime(&p->start_time);
1025 p->security = NULL;
1026 p->io_context = NULL;
1027 p->io_wait = NULL;
1028 p->audit_context = NULL;
Paul Jacksonb4b26412006-01-08 01:01:53 -08001029 cpuset_fork(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030#ifdef CONFIG_NUMA
1031 p->mempolicy = mpol_copy(p->mempolicy);
1032 if (IS_ERR(p->mempolicy)) {
1033 retval = PTR_ERR(p->mempolicy);
1034 p->mempolicy = NULL;
Paul Jacksonb4b26412006-01-08 01:01:53 -08001035 goto bad_fork_cleanup_cpuset;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 }
Paul Jacksonc61afb12006-03-24 03:16:08 -08001037 mpol_fix_fork_child_flag(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038#endif
1039
Ingo Molnar408894e2006-01-09 15:59:20 -08001040#ifdef CONFIG_DEBUG_MUTEXES
1041 p->blocked_on = NULL; /* not blocked yet */
1042#endif
1043
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 p->tgid = p->pid;
1045 if (clone_flags & CLONE_THREAD)
1046 p->tgid = current->tgid;
1047
1048 if ((retval = security_task_alloc(p)))
1049 goto bad_fork_cleanup_policy;
1050 if ((retval = audit_alloc(p)))
1051 goto bad_fork_cleanup_security;
1052 /* copy all the process information */
1053 if ((retval = copy_semundo(clone_flags, p)))
1054 goto bad_fork_cleanup_audit;
1055 if ((retval = copy_files(clone_flags, p)))
1056 goto bad_fork_cleanup_semundo;
1057 if ((retval = copy_fs(clone_flags, p)))
1058 goto bad_fork_cleanup_files;
1059 if ((retval = copy_sighand(clone_flags, p)))
1060 goto bad_fork_cleanup_fs;
1061 if ((retval = copy_signal(clone_flags, p)))
1062 goto bad_fork_cleanup_sighand;
1063 if ((retval = copy_mm(clone_flags, p)))
1064 goto bad_fork_cleanup_signal;
1065 if ((retval = copy_keys(clone_flags, p)))
1066 goto bad_fork_cleanup_mm;
1067 if ((retval = copy_namespace(clone_flags, p)))
1068 goto bad_fork_cleanup_keys;
1069 retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
1070 if (retval)
1071 goto bad_fork_cleanup_namespace;
1072
1073 p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
1074 /*
1075 * Clear TID on mm_release()?
1076 */
1077 p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
Ingo Molnar8f17d3a2006-03-27 01:16:27 -08001078 p->robust_list = NULL;
1079#ifdef CONFIG_COMPAT
1080 p->compat_robust_list = NULL;
1081#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 /*
GOTO Masanorif9a38792006-03-13 21:20:44 -08001083 * sigaltstack should be cleared when sharing the same VM
1084 */
1085 if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
1086 p->sas_ss_sp = p->sas_ss_size = 0;
1087
1088 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 * Syscall tracing should be turned off in the child regardless
1090 * of CLONE_PTRACE.
1091 */
1092 clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
Laurent Viviered75e8d2005-09-03 15:57:18 -07001093#ifdef TIF_SYSCALL_EMU
1094 clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
1095#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096
1097 /* Our parent execution domain becomes current domain
1098 These must match for thread signalling to apply */
1099
1100 p->parent_exec_id = p->self_exec_id;
1101
1102 /* ok, now we should be set up.. */
1103 p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
1104 p->pdeath_signal = 0;
1105 p->exit_state = 0;
1106
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 /*
1108 * Ok, make it visible to the rest of the system.
1109 * We dont wake it up yet.
1110 */
1111 p->group_leader = p;
Oleg Nesterov47e65322006-03-28 16:11:25 -08001112 INIT_LIST_HEAD(&p->thread_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 INIT_LIST_HEAD(&p->ptrace_children);
1114 INIT_LIST_HEAD(&p->ptrace_list);
1115
Nick Piggin476d1392005-06-25 14:57:29 -07001116 /* Perform scheduler related setup. Assign this task to a CPU. */
1117 sched_fork(p, clone_flags);
1118
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 /* Need tasklist lock for parent etc handling! */
1120 write_lock_irq(&tasklist_lock);
1121
1122 /*
Nick Piggin476d1392005-06-25 14:57:29 -07001123 * The task hasn't been attached yet, so its cpus_allowed mask will
1124 * not be changed, nor will its assigned CPU.
1125 *
1126 * The cpus_allowed mask of the parent may have changed after it was
1127 * copied first time - so re-copy it here, then check the child's CPU
1128 * to ensure it is on a valid CPU (and if not, just force it back to
1129 * parent's CPU). This avoids alot of nasty races.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 */
1131 p->cpus_allowed = current->cpus_allowed;
Srivatsa Vaddagiri26ff6ad2005-09-16 19:27:40 -07001132 if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
1133 !cpu_online(task_cpu(p))))
Nick Piggin476d1392005-06-25 14:57:29 -07001134 set_task_cpu(p, smp_processor_id());
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 /* CLONE_PARENT re-uses the old parent */
1137 if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
1138 p->real_parent = current->real_parent;
1139 else
1140 p->real_parent = current;
1141 p->parent = p->real_parent;
1142
Oleg Nesterov3f17da62006-02-15 22:13:24 +03001143 spin_lock(&current->sighand->siglock);
Oleg Nesterov4a2c7a72006-03-28 16:11:26 -08001144
1145 /*
1146 * Process group and session signals need to be delivered to just the
1147 * parent before the fork or both the parent and the child after the
1148 * fork. Restart if a signal comes in before we add the new process to
1149 * it's process group.
1150 * A fatal signal pending means that current will exit, so the new
1151 * thread can't slip out of an OOM kill (or normal SIGKILL).
1152 */
1153 recalc_sigpending();
1154 if (signal_pending(current)) {
1155 spin_unlock(&current->sighand->siglock);
1156 write_unlock_irq(&tasklist_lock);
1157 retval = -ERESTARTNOINTR;
1158 goto bad_fork_cleanup_namespace;
1159 }
1160
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161 if (clone_flags & CLONE_THREAD) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 /*
1163 * Important: if an exit-all has been started then
1164 * do not create this new thread - the whole thread
1165 * group is supposed to exit anyway.
1166 */
1167 if (current->signal->flags & SIGNAL_GROUP_EXIT) {
1168 spin_unlock(&current->sighand->siglock);
1169 write_unlock_irq(&tasklist_lock);
1170 retval = -EAGAIN;
1171 goto bad_fork_cleanup_namespace;
1172 }
Oleg Nesterov47e65322006-03-28 16:11:25 -08001173
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 p->group_leader = current->group_leader;
Oleg Nesterov47e65322006-03-28 16:11:25 -08001175 list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 if (!cputime_eq(current->signal->it_virt_expires,
1178 cputime_zero) ||
1179 !cputime_eq(current->signal->it_prof_expires,
1180 cputime_zero) ||
1181 current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY ||
1182 !list_empty(&current->signal->cpu_timers[0]) ||
1183 !list_empty(&current->signal->cpu_timers[1]) ||
1184 !list_empty(&current->signal->cpu_timers[2])) {
1185 /*
1186 * Have child wake up on its first tick to check
1187 * for process CPU timers.
1188 */
1189 p->it_prof_expires = jiffies_to_cputime(1);
1190 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 }
1192
Jens Axboe22e2c502005-06-27 10:55:12 +02001193 /*
1194 * inherit ioprio
1195 */
1196 p->ioprio = current->ioprio;
1197
Oleg Nesterov73b9ebf2006-03-28 16:11:07 -08001198 if (likely(p->pid)) {
1199 add_parent(p);
1200 if (unlikely(p->ptrace & PT_PTRACED))
1201 __ptrace_link(p, current->parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202
Oleg Nesterov73b9ebf2006-03-28 16:11:07 -08001203 if (thread_group_leader(p)) {
1204 p->signal->tty = current->signal->tty;
1205 p->signal->pgrp = process_group(current);
1206 p->signal->session = current->signal->session;
1207 attach_pid(p, PIDTYPE_PGID, process_group(p));
1208 attach_pid(p, PIDTYPE_SID, p->signal->session);
Oleg Nesterovc97d9892006-03-28 16:11:06 -08001209
Eric W. Biederman5e85d4a2006-04-18 22:20:16 -07001210 list_add_tail_rcu(&p->tasks, &init_task.tasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 __get_cpu_var(process_counts)++;
Oleg Nesterov73b9ebf2006-03-28 16:11:07 -08001212 }
Oleg Nesterov73b9ebf2006-03-28 16:11:07 -08001213 attach_pid(p, PIDTYPE_PID, p->pid);
1214 nr_threads++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 }
1216
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 total_forks++;
Oleg Nesterov3f17da62006-02-15 22:13:24 +03001218 spin_unlock(&current->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 write_unlock_irq(&tasklist_lock);
Andrew Mortonc13cf852005-11-28 13:43:48 -08001220 proc_fork_connector(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 return p;
1222
1223bad_fork_cleanup_namespace:
1224 exit_namespace(p);
1225bad_fork_cleanup_keys:
1226 exit_keys(p);
1227bad_fork_cleanup_mm:
1228 if (p->mm)
1229 mmput(p->mm);
1230bad_fork_cleanup_signal:
Oleg Nesterov6b3934ef2006-03-28 16:11:16 -08001231 cleanup_signal(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232bad_fork_cleanup_sighand:
Oleg Nesterova7e53282006-03-28 16:11:27 -08001233 __cleanup_sighand(p->sighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234bad_fork_cleanup_fs:
1235 exit_fs(p); /* blocking */
1236bad_fork_cleanup_files:
1237 exit_files(p); /* blocking */
1238bad_fork_cleanup_semundo:
1239 exit_sem(p);
1240bad_fork_cleanup_audit:
1241 audit_free(p);
1242bad_fork_cleanup_security:
1243 security_task_free(p);
1244bad_fork_cleanup_policy:
1245#ifdef CONFIG_NUMA
1246 mpol_free(p->mempolicy);
Paul Jacksonb4b26412006-01-08 01:01:53 -08001247bad_fork_cleanup_cpuset:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248#endif
Paul Jacksonb4b26412006-01-08 01:01:53 -08001249 cpuset_exit(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250bad_fork_cleanup:
1251 if (p->binfmt)
1252 module_put(p->binfmt->module);
1253bad_fork_cleanup_put_domain:
Al Viroa1261f542005-11-13 16:06:55 -08001254 module_put(task_thread_info(p)->exec_domain->module);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255bad_fork_cleanup_count:
1256 put_group_info(p->group_info);
1257 atomic_dec(&p->user->processes);
1258 free_uid(p->user);
1259bad_fork_free:
1260 free_task(p);
Oleg Nesterovfe7d37d2006-01-08 01:04:02 -08001261fork_out:
1262 return ERR_PTR(retval);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263}
1264
1265struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
1266{
1267 memset(regs, 0, sizeof(struct pt_regs));
1268 return regs;
1269}
1270
1271task_t * __devinit fork_idle(int cpu)
1272{
1273 task_t *task;
1274 struct pt_regs regs;
1275
1276 task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL, NULL, 0);
1277 if (!task)
1278 return ERR_PTR(-ENOMEM);
1279 init_idle(task, cpu);
Oleg Nesterov73b9ebf2006-03-28 16:11:07 -08001280
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 return task;
1282}
1283
1284static inline int fork_traceflag (unsigned clone_flags)
1285{
1286 if (clone_flags & CLONE_UNTRACED)
1287 return 0;
1288 else if (clone_flags & CLONE_VFORK) {
1289 if (current->ptrace & PT_TRACE_VFORK)
1290 return PTRACE_EVENT_VFORK;
1291 } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
1292 if (current->ptrace & PT_TRACE_CLONE)
1293 return PTRACE_EVENT_CLONE;
1294 } else if (current->ptrace & PT_TRACE_FORK)
1295 return PTRACE_EVENT_FORK;
1296
1297 return 0;
1298}
1299
1300/*
1301 * Ok, this is the main fork-routine.
1302 *
1303 * It copies the process, and if successful kick-starts
1304 * it and waits for it to finish using the VM if required.
1305 */
1306long do_fork(unsigned long clone_flags,
1307 unsigned long stack_start,
1308 struct pt_regs *regs,
1309 unsigned long stack_size,
1310 int __user *parent_tidptr,
1311 int __user *child_tidptr)
1312{
1313 struct task_struct *p;
1314 int trace = 0;
Eric W. Biederman92476d72006-03-31 02:31:42 -08001315 struct pid *pid = alloc_pid();
1316 long nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317
Eric W. Biederman92476d72006-03-31 02:31:42 -08001318 if (!pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 return -EAGAIN;
Eric W. Biederman92476d72006-03-31 02:31:42 -08001320 nr = pid->nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 if (unlikely(current->ptrace)) {
1322 trace = fork_traceflag (clone_flags);
1323 if (trace)
1324 clone_flags |= CLONE_PTRACE;
1325 }
1326
Eric W. Biederman92476d72006-03-31 02:31:42 -08001327 p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 /*
1329 * Do this prior waking up the new thread - the thread pointer
1330 * might get invalid after that point, if the thread exits quickly.
1331 */
1332 if (!IS_ERR(p)) {
1333 struct completion vfork;
1334
1335 if (clone_flags & CLONE_VFORK) {
1336 p->vfork_done = &vfork;
1337 init_completion(&vfork);
1338 }
1339
1340 if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) {
1341 /*
1342 * We'll start up with an immediate SIGSTOP.
1343 */
1344 sigaddset(&p->pending.signal, SIGSTOP);
1345 set_tsk_thread_flag(p, TIF_SIGPENDING);
1346 }
1347
1348 if (!(clone_flags & CLONE_STOPPED))
1349 wake_up_new_task(p, clone_flags);
1350 else
1351 p->state = TASK_STOPPED;
1352
1353 if (unlikely (trace)) {
Eric W. Biederman92476d72006-03-31 02:31:42 -08001354 current->ptrace_message = nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 ptrace_notify ((trace << 8) | SIGTRAP);
1356 }
1357
1358 if (clone_flags & CLONE_VFORK) {
1359 wait_for_completion(&vfork);
1360 if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE))
1361 ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
1362 }
1363 } else {
Eric W. Biederman92476d72006-03-31 02:31:42 -08001364 free_pid(pid);
1365 nr = PTR_ERR(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 }
Eric W. Biederman92476d72006-03-31 02:31:42 -08001367 return nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368}
1369
Ravikiran G Thirumalai5fd63b32006-01-11 22:46:15 +01001370#ifndef ARCH_MIN_MMSTRUCT_ALIGN
1371#define ARCH_MIN_MMSTRUCT_ALIGN 0
1372#endif
1373
Oleg Nesterovaa1757f2006-03-28 16:11:12 -08001374static void sighand_ctor(void *data, kmem_cache_t *cachep, unsigned long flags)
1375{
1376 struct sighand_struct *sighand = data;
1377
1378 if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
1379 SLAB_CTOR_CONSTRUCTOR)
1380 spin_lock_init(&sighand->siglock);
1381}
1382
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383void __init proc_caches_init(void)
1384{
1385 sighand_cachep = kmem_cache_create("sighand_cache",
1386 sizeof(struct sighand_struct), 0,
Oleg Nesterovaa1757f2006-03-28 16:11:12 -08001387 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU,
1388 sighand_ctor, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 signal_cachep = kmem_cache_create("signal_cache",
1390 sizeof(struct signal_struct), 0,
1391 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1392 files_cachep = kmem_cache_create("files_cache",
1393 sizeof(struct files_struct), 0,
1394 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1395 fs_cachep = kmem_cache_create("fs_cache",
1396 sizeof(struct fs_struct), 0,
1397 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1398 vm_area_cachep = kmem_cache_create("vm_area_struct",
1399 sizeof(struct vm_area_struct), 0,
1400 SLAB_PANIC, NULL, NULL);
1401 mm_cachep = kmem_cache_create("mm_struct",
Ravikiran G Thirumalai5fd63b32006-01-11 22:46:15 +01001402 sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001403 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1404}
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001405
1406
1407/*
1408 * Check constraints on flags passed to the unshare system call and
1409 * force unsharing of additional process context as appropriate.
1410 */
1411static inline void check_unshare_flags(unsigned long *flags_ptr)
1412{
1413 /*
1414 * If unsharing a thread from a thread group, must also
1415 * unshare vm.
1416 */
1417 if (*flags_ptr & CLONE_THREAD)
1418 *flags_ptr |= CLONE_VM;
1419
1420 /*
1421 * If unsharing vm, must also unshare signal handlers.
1422 */
1423 if (*flags_ptr & CLONE_VM)
1424 *flags_ptr |= CLONE_SIGHAND;
1425
1426 /*
1427 * If unsharing signal handlers and the task was created
1428 * using CLONE_THREAD, then must unshare the thread
1429 */
1430 if ((*flags_ptr & CLONE_SIGHAND) &&
1431 (atomic_read(&current->signal->count) > 1))
1432 *flags_ptr |= CLONE_THREAD;
1433
1434 /*
1435 * If unsharing namespace, must also unshare filesystem information.
1436 */
1437 if (*flags_ptr & CLONE_NEWNS)
1438 *flags_ptr |= CLONE_FS;
1439}
1440
1441/*
1442 * Unsharing of tasks created with CLONE_THREAD is not supported yet
1443 */
1444static int unshare_thread(unsigned long unshare_flags)
1445{
1446 if (unshare_flags & CLONE_THREAD)
1447 return -EINVAL;
1448
1449 return 0;
1450}
1451
1452/*
JANAK DESAI99d14192006-02-07 12:58:59 -08001453 * Unshare the filesystem structure if it is being shared
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001454 */
1455static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
1456{
1457 struct fs_struct *fs = current->fs;
1458
1459 if ((unshare_flags & CLONE_FS) &&
JANAK DESAI99d14192006-02-07 12:58:59 -08001460 (fs && atomic_read(&fs->count) > 1)) {
1461 *new_fsp = __copy_fs_struct(current->fs);
1462 if (!*new_fsp)
1463 return -ENOMEM;
1464 }
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001465
1466 return 0;
1467}
1468
1469/*
JANAK DESAI741a2952006-02-07 12:59:00 -08001470 * Unshare the namespace structure if it is being shared
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001471 */
JANAK DESAI741a2952006-02-07 12:59:00 -08001472static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs)
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001473{
1474 struct namespace *ns = current->namespace;
1475
1476 if ((unshare_flags & CLONE_NEWNS) &&
JANAK DESAI741a2952006-02-07 12:59:00 -08001477 (ns && atomic_read(&ns->count) > 1)) {
1478 if (!capable(CAP_SYS_ADMIN))
1479 return -EPERM;
1480
1481 *new_nsp = dup_namespace(current, new_fs ? new_fs : current->fs);
1482 if (!*new_nsp)
1483 return -ENOMEM;
1484 }
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001485
1486 return 0;
1487}
1488
1489/*
1490 * Unsharing of sighand for tasks created with CLONE_SIGHAND is not
1491 * supported yet
1492 */
1493static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp)
1494{
1495 struct sighand_struct *sigh = current->sighand;
1496
1497 if ((unshare_flags & CLONE_SIGHAND) &&
1498 (sigh && atomic_read(&sigh->count) > 1))
1499 return -EINVAL;
1500 else
1501 return 0;
1502}
1503
1504/*
JANAK DESAIa0a7ec32006-02-07 12:59:01 -08001505 * Unshare vm if it is being shared
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001506 */
1507static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp)
1508{
1509 struct mm_struct *mm = current->mm;
1510
1511 if ((unshare_flags & CLONE_VM) &&
JANAK DESAIa0a7ec32006-02-07 12:59:01 -08001512 (mm && atomic_read(&mm->mm_users) > 1)) {
Oleg Nesterov2d61b8672006-03-18 20:41:10 +03001513 return -EINVAL;
JANAK DESAIa0a7ec32006-02-07 12:59:01 -08001514 }
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001515
1516 return 0;
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001517}
1518
1519/*
JANAK DESAIa016f332006-02-07 12:59:02 -08001520 * Unshare file descriptor table if it is being shared
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001521 */
1522static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
1523{
1524 struct files_struct *fd = current->files;
JANAK DESAIa016f332006-02-07 12:59:02 -08001525 int error = 0;
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001526
1527 if ((unshare_flags & CLONE_FILES) &&
JANAK DESAIa016f332006-02-07 12:59:02 -08001528 (fd && atomic_read(&fd->count) > 1)) {
1529 *new_fdp = dup_fd(fd, &error);
1530 if (!*new_fdp)
1531 return error;
1532 }
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001533
1534 return 0;
1535}
1536
1537/*
1538 * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not
1539 * supported yet
1540 */
1541static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp)
1542{
1543 if (unshare_flags & CLONE_SYSVSEM)
1544 return -EINVAL;
1545
1546 return 0;
1547}
1548
1549/*
1550 * unshare allows a process to 'unshare' part of the process
1551 * context which was originally shared using clone. copy_*
1552 * functions used by do_fork() cannot be used here directly
1553 * because they modify an inactive task_struct that is being
1554 * constructed. Here we are modifying the current, active,
1555 * task_struct.
1556 */
1557asmlinkage long sys_unshare(unsigned long unshare_flags)
1558{
1559 int err = 0;
1560 struct fs_struct *fs, *new_fs = NULL;
1561 struct namespace *ns, *new_ns = NULL;
1562 struct sighand_struct *sigh, *new_sigh = NULL;
1563 struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
1564 struct files_struct *fd, *new_fd = NULL;
1565 struct sem_undo_list *new_ulist = NULL;
1566
1567 check_unshare_flags(&unshare_flags);
1568
Eric W. Biederman06f9d4f2006-03-22 00:07:40 -08001569 /* Return -EINVAL for all unsupported flags */
1570 err = -EINVAL;
1571 if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
1572 CLONE_VM|CLONE_FILES|CLONE_SYSVSEM))
1573 goto bad_unshare_out;
1574
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001575 if ((err = unshare_thread(unshare_flags)))
1576 goto bad_unshare_out;
1577 if ((err = unshare_fs(unshare_flags, &new_fs)))
1578 goto bad_unshare_cleanup_thread;
JANAK DESAI741a2952006-02-07 12:59:00 -08001579 if ((err = unshare_namespace(unshare_flags, &new_ns, new_fs)))
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001580 goto bad_unshare_cleanup_fs;
1581 if ((err = unshare_sighand(unshare_flags, &new_sigh)))
1582 goto bad_unshare_cleanup_ns;
1583 if ((err = unshare_vm(unshare_flags, &new_mm)))
1584 goto bad_unshare_cleanup_sigh;
1585 if ((err = unshare_fd(unshare_flags, &new_fd)))
1586 goto bad_unshare_cleanup_vm;
1587 if ((err = unshare_semundo(unshare_flags, &new_ulist)))
1588 goto bad_unshare_cleanup_fd;
1589
1590 if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) {
1591
1592 task_lock(current);
1593
1594 if (new_fs) {
1595 fs = current->fs;
1596 current->fs = new_fs;
1597 new_fs = fs;
1598 }
1599
1600 if (new_ns) {
1601 ns = current->namespace;
1602 current->namespace = new_ns;
1603 new_ns = ns;
1604 }
1605
1606 if (new_sigh) {
1607 sigh = current->sighand;
Eric W. Biedermane0e8eb52006-03-16 10:31:38 -07001608 rcu_assign_pointer(current->sighand, new_sigh);
JANAK DESAIcf2e3402006-02-07 12:58:58 -08001609 new_sigh = sigh;
1610 }
1611
1612 if (new_mm) {
1613 mm = current->mm;
1614 active_mm = current->active_mm;
1615 current->mm = new_mm;
1616 current->active_mm = new_mm;
1617 activate_mm(active_mm, new_mm);
1618 new_mm = mm;
1619 }
1620
1621 if (new_fd) {
1622 fd = current->files;
1623 current->files = new_fd;
1624 new_fd = fd;
1625 }
1626
1627 task_unlock(current);
1628 }
1629
1630bad_unshare_cleanup_fd:
1631 if (new_fd)
1632 put_files_struct(new_fd);
1633
1634bad_unshare_cleanup_vm:
1635 if (new_mm)
1636 mmput(new_mm);
1637
1638bad_unshare_cleanup_sigh:
1639 if (new_sigh)
1640 if (atomic_dec_and_test(&new_sigh->count))
1641 kmem_cache_free(sighand_cachep, new_sigh);
1642
1643bad_unshare_cleanup_ns:
1644 if (new_ns)
1645 put_namespace(new_ns);
1646
1647bad_unshare_cleanup_fs:
1648 if (new_fs)
1649 put_fs_struct(new_fs);
1650
1651bad_unshare_cleanup_thread:
1652bad_unshare_out:
1653 return err;
1654}