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> | |
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/completion.h> | |
6b3286ed | 20 | #include <linux/mnt_namespace.h> |
1da177e4 LT |
21 | #include <linux/personality.h> |
22 | #include <linux/mempolicy.h> | |
23 | #include <linux/sem.h> | |
24 | #include <linux/file.h> | |
9f3acc31 | 25 | #include <linux/fdtable.h> |
1da177e4 LT |
26 | #include <linux/key.h> |
27 | #include <linux/binfmts.h> | |
28 | #include <linux/mman.h> | |
29 | #include <linux/fs.h> | |
ab516013 | 30 | #include <linux/nsproxy.h> |
c59ede7b | 31 | #include <linux/capability.h> |
1da177e4 | 32 | #include <linux/cpu.h> |
b4f48b63 | 33 | #include <linux/cgroup.h> |
1da177e4 LT |
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> | |
7c3ab738 | 39 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 40 | #include <linux/rcupdate.h> |
1da177e4 LT |
41 | #include <linux/ptrace.h> |
42 | #include <linux/mount.h> | |
43 | #include <linux/audit.h> | |
78fb7466 | 44 | #include <linux/memcontrol.h> |
1da177e4 LT |
45 | #include <linux/profile.h> |
46 | #include <linux/rmap.h> | |
47 | #include <linux/acct.h> | |
8f0ab514 | 48 | #include <linux/tsacct_kern.h> |
9f46080c | 49 | #include <linux/cn_proc.h> |
ba96a0c8 | 50 | #include <linux/freezer.h> |
ca74e92b | 51 | #include <linux/delayacct.h> |
ad4ecbcb | 52 | #include <linux/taskstats_kern.h> |
0a425405 | 53 | #include <linux/random.h> |
522ed776 | 54 | #include <linux/tty.h> |
6f4e6433 | 55 | #include <linux/proc_fs.h> |
fd0928df | 56 | #include <linux/blkdev.h> |
1da177e4 LT |
57 | |
58 | #include <asm/pgtable.h> | |
59 | #include <asm/pgalloc.h> | |
60 | #include <asm/uaccess.h> | |
61 | #include <asm/mmu_context.h> | |
62 | #include <asm/cacheflush.h> | |
63 | #include <asm/tlbflush.h> | |
64 | ||
65 | /* | |
66 | * Protected counters by write_lock_irq(&tasklist_lock) | |
67 | */ | |
68 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
69 | int nr_threads; /* The idle threads do not count.. */ | |
70 | ||
71 | int max_threads; /* tunable limit on nr_threads */ | |
72 | ||
73 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
74 | ||
c59923a1 | 75 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
76 | |
77 | int nr_processes(void) | |
78 | { | |
79 | int cpu; | |
80 | int total = 0; | |
81 | ||
82 | for_each_online_cpu(cpu) | |
83 | total += per_cpu(process_counts, cpu); | |
84 | ||
85 | return total; | |
86 | } | |
87 | ||
88 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
89 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
90 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 91 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
92 | #endif |
93 | ||
94 | /* SLAB cache for signal_struct structures (tsk->signal) */ | |
e18b890b | 95 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
96 | |
97 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 98 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
99 | |
100 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 101 | struct kmem_cache *files_cachep; |
1da177e4 LT |
102 | |
103 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 104 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
105 | |
106 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 107 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
108 | |
109 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 110 | static struct kmem_cache *mm_cachep; |
1da177e4 LT |
111 | |
112 | void free_task(struct task_struct *tsk) | |
113 | { | |
3e26c149 | 114 | prop_local_destroy_single(&tsk->dirties); |
f7e4217b | 115 | free_thread_info(tsk->stack); |
23f78d4a | 116 | rt_mutex_debug_task_free(tsk); |
1da177e4 LT |
117 | free_task_struct(tsk); |
118 | } | |
119 | EXPORT_SYMBOL(free_task); | |
120 | ||
158d9ebd | 121 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 122 | { |
270f722d | 123 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
124 | WARN_ON(atomic_read(&tsk->usage)); |
125 | WARN_ON(tsk == current); | |
126 | ||
1da177e4 LT |
127 | security_task_free(tsk); |
128 | free_uid(tsk->user); | |
129 | put_group_info(tsk->group_info); | |
35df17c5 | 130 | delayacct_tsk_free(tsk); |
1da177e4 LT |
131 | |
132 | if (!profile_handoff_task(tsk)) | |
133 | free_task(tsk); | |
134 | } | |
135 | ||
2adee9b3 SS |
136 | /* |
137 | * macro override instead of weak attribute alias, to workaround | |
138 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
139 | */ | |
140 | #ifndef arch_task_cache_init | |
141 | #define arch_task_cache_init() | |
142 | #endif | |
61c4628b | 143 | |
1da177e4 LT |
144 | void __init fork_init(unsigned long mempages) |
145 | { | |
146 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
147 | #ifndef ARCH_MIN_TASKALIGN | |
148 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
149 | #endif | |
150 | /* create a slab on which task_structs can be allocated */ | |
151 | task_struct_cachep = | |
152 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
20c2df83 | 153 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL); |
1da177e4 LT |
154 | #endif |
155 | ||
61c4628b SS |
156 | /* do the arch specific task caches init */ |
157 | arch_task_cache_init(); | |
158 | ||
1da177e4 LT |
159 | /* |
160 | * The default maximum number of threads is set to a safe | |
161 | * value: the thread structures can take up at most half | |
162 | * of memory. | |
163 | */ | |
164 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
165 | ||
166 | /* | |
167 | * we need to allow at least 20 threads to boot a system | |
168 | */ | |
169 | if(max_threads < 20) | |
170 | max_threads = 20; | |
171 | ||
172 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
173 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
174 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
175 | init_task.signal->rlim[RLIMIT_NPROC]; | |
176 | } | |
177 | ||
61c4628b SS |
178 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
179 | struct task_struct *src) | |
180 | { | |
181 | *dst = *src; | |
182 | return 0; | |
183 | } | |
184 | ||
1da177e4 LT |
185 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
186 | { | |
187 | struct task_struct *tsk; | |
188 | struct thread_info *ti; | |
3e26c149 | 189 | int err; |
1da177e4 LT |
190 | |
191 | prepare_to_copy(orig); | |
192 | ||
193 | tsk = alloc_task_struct(); | |
194 | if (!tsk) | |
195 | return NULL; | |
196 | ||
197 | ti = alloc_thread_info(tsk); | |
198 | if (!ti) { | |
199 | free_task_struct(tsk); | |
200 | return NULL; | |
201 | } | |
202 | ||
61c4628b SS |
203 | err = arch_dup_task_struct(tsk, orig); |
204 | if (err) | |
205 | goto out; | |
206 | ||
f7e4217b | 207 | tsk->stack = ti; |
3e26c149 PZ |
208 | |
209 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
210 | if (err) |
211 | goto out; | |
3e26c149 | 212 | |
10ebffde | 213 | setup_thread_stack(tsk, orig); |
1da177e4 | 214 | |
0a425405 AV |
215 | #ifdef CONFIG_CC_STACKPROTECTOR |
216 | tsk->stack_canary = get_random_int(); | |
217 | #endif | |
218 | ||
1da177e4 LT |
219 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
220 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 221 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 222 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 223 | tsk->btrace_seq = 0; |
6c5c9341 | 224 | #endif |
a0aa7f68 | 225 | tsk->splice_pipe = NULL; |
1da177e4 | 226 | return tsk; |
61c4628b SS |
227 | |
228 | out: | |
229 | free_thread_info(ti); | |
230 | free_task_struct(tsk); | |
231 | return NULL; | |
1da177e4 LT |
232 | } |
233 | ||
234 | #ifdef CONFIG_MMU | |
a39bc516 | 235 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 236 | { |
fd3e42fc | 237 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
238 | struct rb_node **rb_link, *rb_parent; |
239 | int retval; | |
240 | unsigned long charge; | |
241 | struct mempolicy *pol; | |
242 | ||
243 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 244 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
245 | /* |
246 | * Not linked in yet - no deadlock potential: | |
247 | */ | |
248 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 249 | |
1da177e4 LT |
250 | mm->locked_vm = 0; |
251 | mm->mmap = NULL; | |
252 | mm->mmap_cache = NULL; | |
253 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 254 | mm->cached_hole_size = ~0UL; |
1da177e4 | 255 | mm->map_count = 0; |
1da177e4 LT |
256 | cpus_clear(mm->cpu_vm_mask); |
257 | mm->mm_rb = RB_ROOT; | |
258 | rb_link = &mm->mm_rb.rb_node; | |
259 | rb_parent = NULL; | |
260 | pprev = &mm->mmap; | |
261 | ||
fd3e42fc | 262 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
263 | struct file *file; |
264 | ||
265 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
266 | long pages = vma_pages(mpnt); |
267 | mm->total_vm -= pages; | |
ab50b8ed | 268 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 269 | -pages); |
1da177e4 LT |
270 | continue; |
271 | } | |
272 | charge = 0; | |
273 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
274 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
275 | if (security_vm_enough_memory(len)) | |
276 | goto fail_nomem; | |
277 | charge = len; | |
278 | } | |
e94b1766 | 279 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
280 | if (!tmp) |
281 | goto fail_nomem; | |
282 | *tmp = *mpnt; | |
846a16bf | 283 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
284 | retval = PTR_ERR(pol); |
285 | if (IS_ERR(pol)) | |
286 | goto fail_nomem_policy; | |
287 | vma_set_policy(tmp, pol); | |
288 | tmp->vm_flags &= ~VM_LOCKED; | |
289 | tmp->vm_mm = mm; | |
290 | tmp->vm_next = NULL; | |
291 | anon_vma_link(tmp); | |
292 | file = tmp->vm_file; | |
293 | if (file) { | |
f3a43f3f | 294 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
295 | get_file(file); |
296 | if (tmp->vm_flags & VM_DENYWRITE) | |
297 | atomic_dec(&inode->i_writecount); | |
23ff4440 | 298 | |
1da177e4 LT |
299 | /* insert tmp into the share list, just after mpnt */ |
300 | spin_lock(&file->f_mapping->i_mmap_lock); | |
301 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
302 | flush_dcache_mmap_lock(file->f_mapping); | |
303 | vma_prio_tree_add(tmp, mpnt); | |
304 | flush_dcache_mmap_unlock(file->f_mapping); | |
305 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
306 | } | |
307 | ||
308 | /* | |
7ee78232 | 309 | * Link in the new vma and copy the page table entries. |
1da177e4 | 310 | */ |
1da177e4 LT |
311 | *pprev = tmp; |
312 | pprev = &tmp->vm_next; | |
313 | ||
314 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
315 | rb_link = &tmp->vm_rb.rb_right; | |
316 | rb_parent = &tmp->vm_rb; | |
317 | ||
318 | mm->map_count++; | |
0b0db14c | 319 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
320 | |
321 | if (tmp->vm_ops && tmp->vm_ops->open) | |
322 | tmp->vm_ops->open(tmp); | |
323 | ||
324 | if (retval) | |
325 | goto out; | |
326 | } | |
d6dd61c8 JF |
327 | /* a new mm has just been created */ |
328 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 329 | retval = 0; |
1da177e4 | 330 | out: |
7ee78232 | 331 | up_write(&mm->mmap_sem); |
fd3e42fc | 332 | flush_tlb_mm(oldmm); |
1da177e4 LT |
333 | up_write(&oldmm->mmap_sem); |
334 | return retval; | |
335 | fail_nomem_policy: | |
336 | kmem_cache_free(vm_area_cachep, tmp); | |
337 | fail_nomem: | |
338 | retval = -ENOMEM; | |
339 | vm_unacct_memory(charge); | |
340 | goto out; | |
341 | } | |
342 | ||
343 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
344 | { | |
345 | mm->pgd = pgd_alloc(mm); | |
346 | if (unlikely(!mm->pgd)) | |
347 | return -ENOMEM; | |
348 | return 0; | |
349 | } | |
350 | ||
351 | static inline void mm_free_pgd(struct mm_struct * mm) | |
352 | { | |
5e541973 | 353 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
354 | } |
355 | #else | |
356 | #define dup_mmap(mm, oldmm) (0) | |
357 | #define mm_alloc_pgd(mm) (0) | |
358 | #define mm_free_pgd(mm) | |
359 | #endif /* CONFIG_MMU */ | |
360 | ||
23ff4440 | 361 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 362 | |
e94b1766 | 363 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
364 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
365 | ||
366 | #include <linux/init_task.h> | |
367 | ||
78fb7466 | 368 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
369 | { |
370 | atomic_set(&mm->mm_users, 1); | |
371 | atomic_set(&mm->mm_count, 1); | |
372 | init_rwsem(&mm->mmap_sem); | |
373 | INIT_LIST_HEAD(&mm->mmlist); | |
3cb4a0bb KH |
374 | mm->flags = (current->mm) ? current->mm->flags |
375 | : MMF_DUMP_FILTER_DEFAULT; | |
1da177e4 LT |
376 | mm->core_waiters = 0; |
377 | mm->nr_ptes = 0; | |
4294621f | 378 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 379 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
380 | spin_lock_init(&mm->page_table_lock); |
381 | rwlock_init(&mm->ioctx_list_lock); | |
382 | mm->ioctx_list = NULL; | |
1da177e4 | 383 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 384 | mm->cached_hole_size = ~0UL; |
cf475ad2 | 385 | mm_init_owner(mm, p); |
1da177e4 LT |
386 | |
387 | if (likely(!mm_alloc_pgd(mm))) { | |
388 | mm->def_flags = 0; | |
389 | return mm; | |
390 | } | |
78fb7466 | 391 | |
1da177e4 LT |
392 | free_mm(mm); |
393 | return NULL; | |
394 | } | |
395 | ||
396 | /* | |
397 | * Allocate and initialize an mm_struct. | |
398 | */ | |
399 | struct mm_struct * mm_alloc(void) | |
400 | { | |
401 | struct mm_struct * mm; | |
402 | ||
403 | mm = allocate_mm(); | |
404 | if (mm) { | |
405 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 406 | mm = mm_init(mm, current); |
1da177e4 LT |
407 | } |
408 | return mm; | |
409 | } | |
410 | ||
411 | /* | |
412 | * Called when the last reference to the mm | |
413 | * is dropped: either by a lazy thread or by | |
414 | * mmput. Free the page directory and the mm. | |
415 | */ | |
7ad5b3a5 | 416 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
417 | { |
418 | BUG_ON(mm == &init_mm); | |
419 | mm_free_pgd(mm); | |
420 | destroy_context(mm); | |
421 | free_mm(mm); | |
422 | } | |
6d4e4c4f | 423 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
424 | |
425 | /* | |
426 | * Decrement the use count and release all resources for an mm. | |
427 | */ | |
428 | void mmput(struct mm_struct *mm) | |
429 | { | |
0ae26f1b AM |
430 | might_sleep(); |
431 | ||
1da177e4 LT |
432 | if (atomic_dec_and_test(&mm->mm_users)) { |
433 | exit_aio(mm); | |
434 | exit_mmap(mm); | |
925d1c40 | 435 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
436 | if (!list_empty(&mm->mmlist)) { |
437 | spin_lock(&mmlist_lock); | |
438 | list_del(&mm->mmlist); | |
439 | spin_unlock(&mmlist_lock); | |
440 | } | |
441 | put_swap_token(mm); | |
442 | mmdrop(mm); | |
443 | } | |
444 | } | |
445 | EXPORT_SYMBOL_GPL(mmput); | |
446 | ||
447 | /** | |
448 | * get_task_mm - acquire a reference to the task's mm | |
449 | * | |
450 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning | |
451 | * this kernel workthread has transiently adopted a user mm with use_mm, | |
452 | * to do its AIO) is not set and if so returns a reference to it, after | |
453 | * bumping up the use count. User must release the mm via mmput() | |
454 | * after use. Typically used by /proc and ptrace. | |
455 | */ | |
456 | struct mm_struct *get_task_mm(struct task_struct *task) | |
457 | { | |
458 | struct mm_struct *mm; | |
459 | ||
460 | task_lock(task); | |
461 | mm = task->mm; | |
462 | if (mm) { | |
463 | if (task->flags & PF_BORROWED_MM) | |
464 | mm = NULL; | |
465 | else | |
466 | atomic_inc(&mm->mm_users); | |
467 | } | |
468 | task_unlock(task); | |
469 | return mm; | |
470 | } | |
471 | EXPORT_SYMBOL_GPL(get_task_mm); | |
472 | ||
473 | /* Please note the differences between mmput and mm_release. | |
474 | * mmput is called whenever we stop holding onto a mm_struct, | |
475 | * error success whatever. | |
476 | * | |
477 | * mm_release is called after a mm_struct has been removed | |
478 | * from the current process. | |
479 | * | |
480 | * This difference is important for error handling, when we | |
481 | * only half set up a mm_struct for a new process and need to restore | |
482 | * the old one. Because we mmput the new mm_struct before | |
483 | * restoring the old one. . . | |
484 | * Eric Biederman 10 January 1998 | |
485 | */ | |
486 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
487 | { | |
488 | struct completion *vfork_done = tsk->vfork_done; | |
489 | ||
490 | /* Get rid of any cached register state */ | |
491 | deactivate_mm(tsk, mm); | |
492 | ||
493 | /* notify parent sleeping on vfork() */ | |
494 | if (vfork_done) { | |
495 | tsk->vfork_done = NULL; | |
496 | complete(vfork_done); | |
497 | } | |
fec1d011 RM |
498 | |
499 | /* | |
500 | * If we're exiting normally, clear a user-space tid field if | |
501 | * requested. We leave this alone when dying by signal, to leave | |
502 | * the value intact in a core dump, and to save the unnecessary | |
503 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
504 | */ | |
505 | if (tsk->clear_child_tid | |
506 | && !(tsk->flags & PF_SIGNALED) | |
507 | && atomic_read(&mm->mm_users) > 1) { | |
1da177e4 LT |
508 | u32 __user * tidptr = tsk->clear_child_tid; |
509 | tsk->clear_child_tid = NULL; | |
510 | ||
511 | /* | |
512 | * We don't check the error code - if userspace has | |
513 | * not set up a proper pointer then tough luck. | |
514 | */ | |
515 | put_user(0, tidptr); | |
516 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
517 | } | |
518 | } | |
519 | ||
a0a7ec30 JD |
520 | /* |
521 | * Allocate a new mm structure and copy contents from the | |
522 | * mm structure of the passed in task structure. | |
523 | */ | |
402b0862 | 524 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
525 | { |
526 | struct mm_struct *mm, *oldmm = current->mm; | |
527 | int err; | |
528 | ||
529 | if (!oldmm) | |
530 | return NULL; | |
531 | ||
532 | mm = allocate_mm(); | |
533 | if (!mm) | |
534 | goto fail_nomem; | |
535 | ||
536 | memcpy(mm, oldmm, sizeof(*mm)); | |
537 | ||
7602bdf2 AC |
538 | /* Initializing for Swap token stuff */ |
539 | mm->token_priority = 0; | |
540 | mm->last_interval = 0; | |
541 | ||
78fb7466 | 542 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
543 | goto fail_nomem; |
544 | ||
545 | if (init_new_context(tsk, mm)) | |
546 | goto fail_nocontext; | |
547 | ||
925d1c40 MH |
548 | dup_mm_exe_file(oldmm, mm); |
549 | ||
a0a7ec30 JD |
550 | err = dup_mmap(mm, oldmm); |
551 | if (err) | |
552 | goto free_pt; | |
553 | ||
554 | mm->hiwater_rss = get_mm_rss(mm); | |
555 | mm->hiwater_vm = mm->total_vm; | |
556 | ||
557 | return mm; | |
558 | ||
559 | free_pt: | |
560 | mmput(mm); | |
561 | ||
562 | fail_nomem: | |
563 | return NULL; | |
564 | ||
565 | fail_nocontext: | |
566 | /* | |
567 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
568 | * because it calls destroy_context() | |
569 | */ | |
570 | mm_free_pgd(mm); | |
571 | free_mm(mm); | |
572 | return NULL; | |
573 | } | |
574 | ||
1da177e4 LT |
575 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
576 | { | |
577 | struct mm_struct * mm, *oldmm; | |
578 | int retval; | |
579 | ||
580 | tsk->min_flt = tsk->maj_flt = 0; | |
581 | tsk->nvcsw = tsk->nivcsw = 0; | |
582 | ||
583 | tsk->mm = NULL; | |
584 | tsk->active_mm = NULL; | |
585 | ||
586 | /* | |
587 | * Are we cloning a kernel thread? | |
588 | * | |
589 | * We need to steal a active VM for that.. | |
590 | */ | |
591 | oldmm = current->mm; | |
592 | if (!oldmm) | |
593 | return 0; | |
594 | ||
595 | if (clone_flags & CLONE_VM) { | |
596 | atomic_inc(&oldmm->mm_users); | |
597 | mm = oldmm; | |
1da177e4 LT |
598 | goto good_mm; |
599 | } | |
600 | ||
601 | retval = -ENOMEM; | |
a0a7ec30 | 602 | mm = dup_mm(tsk); |
1da177e4 LT |
603 | if (!mm) |
604 | goto fail_nomem; | |
605 | ||
1da177e4 | 606 | good_mm: |
7602bdf2 AC |
607 | /* Initializing for Swap token stuff */ |
608 | mm->token_priority = 0; | |
609 | mm->last_interval = 0; | |
610 | ||
1da177e4 LT |
611 | tsk->mm = mm; |
612 | tsk->active_mm = mm; | |
613 | return 0; | |
614 | ||
1da177e4 LT |
615 | fail_nomem: |
616 | return retval; | |
1da177e4 LT |
617 | } |
618 | ||
a39bc516 | 619 | static struct fs_struct *__copy_fs_struct(struct fs_struct *old) |
1da177e4 LT |
620 | { |
621 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
622 | /* We don't need to lock fs - think why ;-) */ | |
623 | if (fs) { | |
624 | atomic_set(&fs->count, 1); | |
625 | rwlock_init(&fs->lock); | |
626 | fs->umask = old->umask; | |
627 | read_lock(&old->lock); | |
6ac08c39 JB |
628 | fs->root = old->root; |
629 | path_get(&old->root); | |
630 | fs->pwd = old->pwd; | |
631 | path_get(&old->pwd); | |
632 | if (old->altroot.dentry) { | |
633 | fs->altroot = old->altroot; | |
634 | path_get(&old->altroot); | |
1da177e4 | 635 | } else { |
6ac08c39 JB |
636 | fs->altroot.mnt = NULL; |
637 | fs->altroot.dentry = NULL; | |
1da177e4 LT |
638 | } |
639 | read_unlock(&old->lock); | |
640 | } | |
641 | return fs; | |
642 | } | |
643 | ||
644 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
645 | { | |
646 | return __copy_fs_struct(old); | |
647 | } | |
648 | ||
649 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
650 | ||
a39bc516 | 651 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
652 | { |
653 | if (clone_flags & CLONE_FS) { | |
654 | atomic_inc(¤t->fs->count); | |
655 | return 0; | |
656 | } | |
657 | tsk->fs = __copy_fs_struct(current->fs); | |
658 | if (!tsk->fs) | |
659 | return -ENOMEM; | |
660 | return 0; | |
661 | } | |
662 | ||
a016f338 JD |
663 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
664 | { | |
665 | struct files_struct *oldf, *newf; | |
666 | int error = 0; | |
667 | ||
668 | /* | |
669 | * A background process may not have any files ... | |
670 | */ | |
671 | oldf = current->files; | |
672 | if (!oldf) | |
673 | goto out; | |
674 | ||
675 | if (clone_flags & CLONE_FILES) { | |
676 | atomic_inc(&oldf->count); | |
677 | goto out; | |
678 | } | |
679 | ||
a016f338 JD |
680 | newf = dup_fd(oldf, &error); |
681 | if (!newf) | |
682 | goto out; | |
683 | ||
684 | tsk->files = newf; | |
685 | error = 0; | |
686 | out: | |
687 | return error; | |
688 | } | |
689 | ||
fadad878 | 690 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
691 | { |
692 | #ifdef CONFIG_BLOCK | |
693 | struct io_context *ioc = current->io_context; | |
694 | ||
695 | if (!ioc) | |
696 | return 0; | |
fadad878 JA |
697 | /* |
698 | * Share io context with parent, if CLONE_IO is set | |
699 | */ | |
700 | if (clone_flags & CLONE_IO) { | |
701 | tsk->io_context = ioc_task_link(ioc); | |
702 | if (unlikely(!tsk->io_context)) | |
703 | return -ENOMEM; | |
704 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
705 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
706 | if (unlikely(!tsk->io_context)) | |
707 | return -ENOMEM; | |
708 | ||
fd0928df JA |
709 | tsk->io_context->ioprio = ioc->ioprio; |
710 | } | |
711 | #endif | |
712 | return 0; | |
713 | } | |
714 | ||
a39bc516 | 715 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
716 | { |
717 | struct sighand_struct *sig; | |
718 | ||
719 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
720 | atomic_inc(¤t->sighand->count); | |
721 | return 0; | |
722 | } | |
723 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 724 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
725 | if (!sig) |
726 | return -ENOMEM; | |
1da177e4 LT |
727 | atomic_set(&sig->count, 1); |
728 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
729 | return 0; | |
730 | } | |
731 | ||
a7e5328a | 732 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 733 | { |
c81addc9 ON |
734 | if (atomic_dec_and_test(&sighand->count)) |
735 | kmem_cache_free(sighand_cachep, sighand); | |
736 | } | |
737 | ||
a39bc516 | 738 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
739 | { |
740 | struct signal_struct *sig; | |
741 | int ret; | |
742 | ||
743 | if (clone_flags & CLONE_THREAD) { | |
744 | atomic_inc(¤t->signal->count); | |
745 | atomic_inc(¤t->signal->live); | |
746 | return 0; | |
747 | } | |
748 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
749 | tsk->signal = sig; | |
750 | if (!sig) | |
751 | return -ENOMEM; | |
752 | ||
753 | ret = copy_thread_group_keys(tsk); | |
754 | if (ret < 0) { | |
755 | kmem_cache_free(signal_cachep, sig); | |
756 | return ret; | |
757 | } | |
758 | ||
759 | atomic_set(&sig->count, 1); | |
760 | atomic_set(&sig->live, 1); | |
761 | init_waitqueue_head(&sig->wait_chldexit); | |
762 | sig->flags = 0; | |
763 | sig->group_exit_code = 0; | |
764 | sig->group_exit_task = NULL; | |
765 | sig->group_stop_count = 0; | |
db51aecc | 766 | sig->curr_target = tsk; |
1da177e4 LT |
767 | init_sigpending(&sig->shared_pending); |
768 | INIT_LIST_HEAD(&sig->posix_timers); | |
769 | ||
c9cb2e3d | 770 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
2ff678b8 | 771 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 772 | sig->real_timer.function = it_real_fn; |
1da177e4 LT |
773 | |
774 | sig->it_virt_expires = cputime_zero; | |
775 | sig->it_virt_incr = cputime_zero; | |
776 | sig->it_prof_expires = cputime_zero; | |
777 | sig->it_prof_incr = cputime_zero; | |
778 | ||
1da177e4 | 779 | sig->leader = 0; /* session leadership doesn't inherit */ |
ab521dc0 | 780 | sig->tty_old_pgrp = NULL; |
1da177e4 LT |
781 | |
782 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
9ac52315 LV |
783 | sig->gtime = cputime_zero; |
784 | sig->cgtime = cputime_zero; | |
1da177e4 LT |
785 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
786 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
6eaeeaba | 787 | sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; |
172ba844 | 788 | sig->sum_sched_runtime = 0; |
1da177e4 LT |
789 | INIT_LIST_HEAD(&sig->cpu_timers[0]); |
790 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
791 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
ad4ecbcb | 792 | taskstats_tgid_init(sig); |
1da177e4 LT |
793 | |
794 | task_lock(current->group_leader); | |
795 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
796 | task_unlock(current->group_leader); | |
797 | ||
798 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
799 | /* | |
800 | * New sole thread in the process gets an expiry time | |
801 | * of the whole CPU time limit. | |
802 | */ | |
803 | tsk->it_prof_expires = | |
804 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
805 | } | |
0e464814 | 806 | acct_init_pacct(&sig->pacct); |
1da177e4 | 807 | |
522ed776 MT |
808 | tty_audit_fork(sig); |
809 | ||
1da177e4 LT |
810 | return 0; |
811 | } | |
812 | ||
6b3934ef ON |
813 | void __cleanup_signal(struct signal_struct *sig) |
814 | { | |
815 | exit_thread_group_keys(sig); | |
816 | kmem_cache_free(signal_cachep, sig); | |
817 | } | |
818 | ||
a39bc516 | 819 | static void cleanup_signal(struct task_struct *tsk) |
6b3934ef ON |
820 | { |
821 | struct signal_struct *sig = tsk->signal; | |
822 | ||
823 | atomic_dec(&sig->live); | |
824 | ||
825 | if (atomic_dec_and_test(&sig->count)) | |
826 | __cleanup_signal(sig); | |
827 | } | |
828 | ||
a39bc516 | 829 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
830 | { |
831 | unsigned long new_flags = p->flags; | |
832 | ||
83144186 | 833 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 LT |
834 | new_flags |= PF_FORKNOEXEC; |
835 | if (!(clone_flags & CLONE_PTRACE)) | |
836 | p->ptrace = 0; | |
837 | p->flags = new_flags; | |
2e131895 | 838 | clear_freeze_flag(p); |
1da177e4 LT |
839 | } |
840 | ||
841 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
842 | { | |
843 | current->clear_child_tid = tidptr; | |
844 | ||
b488893a | 845 | return task_pid_vnr(current); |
1da177e4 LT |
846 | } |
847 | ||
a39bc516 | 848 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 849 | { |
23f78d4a | 850 | spin_lock_init(&p->pi_lock); |
e29e175b | 851 | #ifdef CONFIG_RT_MUTEXES |
23f78d4a IM |
852 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
853 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
854 | #endif |
855 | } | |
856 | ||
cf475ad2 BS |
857 | #ifdef CONFIG_MM_OWNER |
858 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
859 | { | |
860 | mm->owner = p; | |
861 | } | |
862 | #endif /* CONFIG_MM_OWNER */ | |
863 | ||
1da177e4 LT |
864 | /* |
865 | * This creates a new process as a copy of the old one, | |
866 | * but does not actually start it yet. | |
867 | * | |
868 | * It copies the registers, and all the appropriate | |
869 | * parts of the process environment (as per the clone | |
870 | * flags). The actual kick-off is left to the caller. | |
871 | */ | |
36c8b586 IM |
872 | static struct task_struct *copy_process(unsigned long clone_flags, |
873 | unsigned long stack_start, | |
874 | struct pt_regs *regs, | |
875 | unsigned long stack_size, | |
36c8b586 | 876 | int __user *child_tidptr, |
85868995 | 877 | struct pid *pid) |
1da177e4 LT |
878 | { |
879 | int retval; | |
a24efe62 | 880 | struct task_struct *p; |
b4f48b63 | 881 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
882 | |
883 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
884 | return ERR_PTR(-EINVAL); | |
885 | ||
886 | /* | |
887 | * Thread groups must share signals as well, and detached threads | |
888 | * can only be started up within the thread group. | |
889 | */ | |
890 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
891 | return ERR_PTR(-EINVAL); | |
892 | ||
893 | /* | |
894 | * Shared signal handlers imply shared VM. By way of the above, | |
895 | * thread groups also imply shared VM. Blocking this case allows | |
896 | * for various simplifications in other code. | |
897 | */ | |
898 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
899 | return ERR_PTR(-EINVAL); | |
900 | ||
901 | retval = security_task_create(clone_flags); | |
902 | if (retval) | |
903 | goto fork_out; | |
904 | ||
905 | retval = -ENOMEM; | |
906 | p = dup_task_struct(current); | |
907 | if (!p) | |
908 | goto fork_out; | |
909 | ||
bea493a0 PZ |
910 | rt_mutex_init_task(p); |
911 | ||
de30a2b3 IM |
912 | #ifdef CONFIG_TRACE_IRQFLAGS |
913 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); | |
914 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
915 | #endif | |
1da177e4 LT |
916 | retval = -EAGAIN; |
917 | if (atomic_read(&p->user->processes) >= | |
918 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
919 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
acce292c | 920 | p->user != current->nsproxy->user_ns->root_user) |
1da177e4 LT |
921 | goto bad_fork_free; |
922 | } | |
923 | ||
924 | atomic_inc(&p->user->__count); | |
925 | atomic_inc(&p->user->processes); | |
926 | get_group_info(p->group_info); | |
927 | ||
928 | /* | |
929 | * If multiple threads are within copy_process(), then this check | |
930 | * triggers too late. This doesn't hurt, the check is only there | |
931 | * to stop root fork bombs. | |
932 | */ | |
933 | if (nr_threads >= max_threads) | |
934 | goto bad_fork_cleanup_count; | |
935 | ||
a1261f54 | 936 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
937 | goto bad_fork_cleanup_count; |
938 | ||
939 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
940 | goto bad_fork_cleanup_put_domain; | |
941 | ||
942 | p->did_exec = 0; | |
ca74e92b | 943 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 944 | copy_flags(clone_flags, p); |
1da177e4 LT |
945 | INIT_LIST_HEAD(&p->children); |
946 | INIT_LIST_HEAD(&p->sibling); | |
e260be67 PM |
947 | #ifdef CONFIG_PREEMPT_RCU |
948 | p->rcu_read_lock_nesting = 0; | |
949 | p->rcu_flipctr_idx = 0; | |
950 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1da177e4 LT |
951 | p->vfork_done = NULL; |
952 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
953 | |
954 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
955 | init_sigpending(&p->pending); | |
956 | ||
957 | p->utime = cputime_zero; | |
958 | p->stime = cputime_zero; | |
9ac52315 | 959 | p->gtime = cputime_zero; |
c66f08be MN |
960 | p->utimescaled = cputime_zero; |
961 | p->stimescaled = cputime_zero; | |
73a2bcb0 | 962 | p->prev_utime = cputime_zero; |
9301899b | 963 | p->prev_stime = cputime_zero; |
172ba844 | 964 | |
82a1fcb9 IM |
965 | #ifdef CONFIG_DETECT_SOFTLOCKUP |
966 | p->last_switch_count = 0; | |
967 | p->last_switch_timestamp = 0; | |
968 | #endif | |
969 | ||
4b98d11b | 970 | #ifdef CONFIG_TASK_XACCT |
1da177e4 LT |
971 | p->rchar = 0; /* I/O counter: bytes read */ |
972 | p->wchar = 0; /* I/O counter: bytes written */ | |
973 | p->syscr = 0; /* I/O counter: read syscalls */ | |
974 | p->syscw = 0; /* I/O counter: write syscalls */ | |
4b98d11b | 975 | #endif |
7c3ab738 | 976 | task_io_accounting_init(p); |
1da177e4 LT |
977 | acct_clear_integrals(p); |
978 | ||
23ff4440 | 979 | p->it_virt_expires = cputime_zero; |
1da177e4 | 980 | p->it_prof_expires = cputime_zero; |
23ff4440 DW |
981 | p->it_sched_expires = 0; |
982 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
983 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
984 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1da177e4 LT |
985 | |
986 | p->lock_depth = -1; /* -1 = no lock */ | |
987 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
988 | p->real_start_time = p->start_time; |
989 | monotonic_to_bootbased(&p->real_start_time); | |
57c521ce | 990 | #ifdef CONFIG_SECURITY |
1da177e4 | 991 | p->security = NULL; |
57c521ce | 992 | #endif |
3b7391de | 993 | p->cap_bset = current->cap_bset; |
1da177e4 | 994 | p->io_context = NULL; |
1da177e4 | 995 | p->audit_context = NULL; |
b4f48b63 | 996 | cgroup_fork(p); |
1da177e4 | 997 | #ifdef CONFIG_NUMA |
846a16bf | 998 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
999 | if (IS_ERR(p->mempolicy)) { |
1000 | retval = PTR_ERR(p->mempolicy); | |
1001 | p->mempolicy = NULL; | |
b4f48b63 | 1002 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1003 | } |
c61afb18 | 1004 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1005 | #endif |
de30a2b3 IM |
1006 | #ifdef CONFIG_TRACE_IRQFLAGS |
1007 | p->irq_events = 0; | |
b36e4758 RK |
1008 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1009 | p->hardirqs_enabled = 1; | |
1010 | #else | |
de30a2b3 | 1011 | p->hardirqs_enabled = 0; |
b36e4758 | 1012 | #endif |
de30a2b3 IM |
1013 | p->hardirq_enable_ip = 0; |
1014 | p->hardirq_enable_event = 0; | |
1015 | p->hardirq_disable_ip = _THIS_IP_; | |
1016 | p->hardirq_disable_event = 0; | |
1017 | p->softirqs_enabled = 1; | |
1018 | p->softirq_enable_ip = _THIS_IP_; | |
1019 | p->softirq_enable_event = 0; | |
1020 | p->softirq_disable_ip = 0; | |
1021 | p->softirq_disable_event = 0; | |
1022 | p->hardirq_context = 0; | |
1023 | p->softirq_context = 0; | |
1024 | #endif | |
fbb9ce95 IM |
1025 | #ifdef CONFIG_LOCKDEP |
1026 | p->lockdep_depth = 0; /* no locks held yet */ | |
1027 | p->curr_chain_key = 0; | |
1028 | p->lockdep_recursion = 0; | |
1029 | #endif | |
1da177e4 | 1030 | |
408894ee IM |
1031 | #ifdef CONFIG_DEBUG_MUTEXES |
1032 | p->blocked_on = NULL; /* not blocked yet */ | |
1033 | #endif | |
1034 | ||
3c90e6e9 SV |
1035 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1036 | sched_fork(p, clone_flags); | |
1037 | ||
1da177e4 LT |
1038 | if ((retval = security_task_alloc(p))) |
1039 | goto bad_fork_cleanup_policy; | |
1040 | if ((retval = audit_alloc(p))) | |
1041 | goto bad_fork_cleanup_security; | |
1042 | /* copy all the process information */ | |
1043 | if ((retval = copy_semundo(clone_flags, p))) | |
1044 | goto bad_fork_cleanup_audit; | |
1045 | if ((retval = copy_files(clone_flags, p))) | |
1046 | goto bad_fork_cleanup_semundo; | |
1047 | if ((retval = copy_fs(clone_flags, p))) | |
1048 | goto bad_fork_cleanup_files; | |
1049 | if ((retval = copy_sighand(clone_flags, p))) | |
1050 | goto bad_fork_cleanup_fs; | |
1051 | if ((retval = copy_signal(clone_flags, p))) | |
1052 | goto bad_fork_cleanup_sighand; | |
1053 | if ((retval = copy_mm(clone_flags, p))) | |
1054 | goto bad_fork_cleanup_signal; | |
1055 | if ((retval = copy_keys(clone_flags, p))) | |
1056 | goto bad_fork_cleanup_mm; | |
ab516013 | 1057 | if ((retval = copy_namespaces(clone_flags, p))) |
1da177e4 | 1058 | goto bad_fork_cleanup_keys; |
fadad878 | 1059 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1060 | goto bad_fork_cleanup_namespaces; |
1da177e4 LT |
1061 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); |
1062 | if (retval) | |
fd0928df | 1063 | goto bad_fork_cleanup_io; |
1da177e4 | 1064 | |
425fb2b4 PE |
1065 | if (pid != &init_struct_pid) { |
1066 | retval = -ENOMEM; | |
1067 | pid = alloc_pid(task_active_pid_ns(p)); | |
1068 | if (!pid) | |
fd0928df | 1069 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1070 | |
1071 | if (clone_flags & CLONE_NEWPID) { | |
1072 | retval = pid_ns_prepare_proc(task_active_pid_ns(p)); | |
1073 | if (retval < 0) | |
1074 | goto bad_fork_free_pid; | |
1075 | } | |
425fb2b4 PE |
1076 | } |
1077 | ||
1078 | p->pid = pid_nr(pid); | |
1079 | p->tgid = p->pid; | |
1080 | if (clone_flags & CLONE_THREAD) | |
1081 | p->tgid = current->tgid; | |
1082 | ||
1da177e4 LT |
1083 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1084 | /* | |
1085 | * Clear TID on mm_release()? | |
1086 | */ | |
1087 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1088 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1089 | p->robust_list = NULL; |
1090 | #ifdef CONFIG_COMPAT | |
1091 | p->compat_robust_list = NULL; | |
1092 | #endif | |
c87e2837 IM |
1093 | INIT_LIST_HEAD(&p->pi_state_list); |
1094 | p->pi_state_cache = NULL; | |
42b2dd0a | 1095 | #endif |
f9a3879a GM |
1096 | /* |
1097 | * sigaltstack should be cleared when sharing the same VM | |
1098 | */ | |
1099 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1100 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1101 | ||
1da177e4 LT |
1102 | /* |
1103 | * Syscall tracing should be turned off in the child regardless | |
1104 | * of CLONE_PTRACE. | |
1105 | */ | |
1106 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1107 | #ifdef TIF_SYSCALL_EMU |
1108 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1109 | #endif | |
9745512c | 1110 | clear_all_latency_tracing(p); |
1da177e4 LT |
1111 | |
1112 | /* Our parent execution domain becomes current domain | |
1113 | These must match for thread signalling to apply */ | |
1da177e4 LT |
1114 | p->parent_exec_id = p->self_exec_id; |
1115 | ||
1116 | /* ok, now we should be set up.. */ | |
1117 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1118 | p->pdeath_signal = 0; | |
1119 | p->exit_state = 0; | |
1120 | ||
1da177e4 LT |
1121 | /* |
1122 | * Ok, make it visible to the rest of the system. | |
1123 | * We dont wake it up yet. | |
1124 | */ | |
1125 | p->group_leader = p; | |
47e65328 | 1126 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 LT |
1127 | INIT_LIST_HEAD(&p->ptrace_children); |
1128 | INIT_LIST_HEAD(&p->ptrace_list); | |
1129 | ||
b4f48b63 PM |
1130 | /* Now that the task is set up, run cgroup callbacks if |
1131 | * necessary. We need to run them before the task is visible | |
1132 | * on the tasklist. */ | |
1133 | cgroup_fork_callbacks(p); | |
1134 | cgroup_callbacks_done = 1; | |
1135 | ||
1da177e4 LT |
1136 | /* Need tasklist lock for parent etc handling! */ |
1137 | write_lock_irq(&tasklist_lock); | |
1138 | ||
1139 | /* | |
476d139c NP |
1140 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1141 | * not be changed, nor will its assigned CPU. | |
1142 | * | |
1143 | * The cpus_allowed mask of the parent may have changed after it was | |
1144 | * copied first time - so re-copy it here, then check the child's CPU | |
1145 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1146 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1147 | */ |
1148 | p->cpus_allowed = current->cpus_allowed; | |
6f505b16 | 1149 | p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed; |
26ff6ad9 SV |
1150 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1151 | !cpu_online(task_cpu(p)))) | |
476d139c | 1152 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1153 | |
1da177e4 LT |
1154 | /* CLONE_PARENT re-uses the old parent */ |
1155 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1156 | p->real_parent = current->real_parent; | |
1157 | else | |
1158 | p->real_parent = current; | |
1159 | p->parent = p->real_parent; | |
1160 | ||
3f17da69 | 1161 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1162 | |
1163 | /* | |
1164 | * Process group and session signals need to be delivered to just the | |
1165 | * parent before the fork or both the parent and the child after the | |
1166 | * fork. Restart if a signal comes in before we add the new process to | |
1167 | * it's process group. | |
1168 | * A fatal signal pending means that current will exit, so the new | |
1169 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1170 | */ | |
23ff4440 | 1171 | recalc_sigpending(); |
4a2c7a78 ON |
1172 | if (signal_pending(current)) { |
1173 | spin_unlock(¤t->sighand->siglock); | |
1174 | write_unlock_irq(&tasklist_lock); | |
1175 | retval = -ERESTARTNOINTR; | |
425fb2b4 | 1176 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1177 | } |
1178 | ||
1da177e4 | 1179 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1180 | p->group_leader = current->group_leader; |
47e65328 | 1181 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1182 | |
1da177e4 LT |
1183 | if (!cputime_eq(current->signal->it_virt_expires, |
1184 | cputime_zero) || | |
1185 | !cputime_eq(current->signal->it_prof_expires, | |
1186 | cputime_zero) || | |
1187 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1188 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1189 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1190 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1191 | /* | |
1192 | * Have child wake up on its first tick to check | |
1193 | * for process CPU timers. | |
1194 | */ | |
1195 | p->it_prof_expires = jiffies_to_cputime(1); | |
1196 | } | |
1da177e4 LT |
1197 | } |
1198 | ||
73b9ebfe ON |
1199 | if (likely(p->pid)) { |
1200 | add_parent(p); | |
1201 | if (unlikely(p->ptrace & PT_PTRACED)) | |
1202 | __ptrace_link(p, current->parent); | |
1203 | ||
1204 | if (thread_group_leader(p)) { | |
5cd17569 | 1205 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1206 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1207 | |
fea9d175 | 1208 | p->signal->leader_pid = pid; |
5cd17569 EB |
1209 | p->signal->tty = current->signal->tty; |
1210 | set_task_pgrp(p, task_pgrp_nr(current)); | |
1211 | set_task_session(p, task_session_nr(current)); | |
1212 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); | |
1213 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
5e85d4ab | 1214 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1215 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1216 | } |
85868995 | 1217 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1218 | nr_threads++; |
1da177e4 LT |
1219 | } |
1220 | ||
1da177e4 | 1221 | total_forks++; |
3f17da69 | 1222 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1223 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1224 | proc_fork_connector(p); |
817929ec | 1225 | cgroup_post_fork(p); |
1da177e4 LT |
1226 | return p; |
1227 | ||
425fb2b4 PE |
1228 | bad_fork_free_pid: |
1229 | if (pid != &init_struct_pid) | |
1230 | free_pid(pid); | |
fd0928df JA |
1231 | bad_fork_cleanup_io: |
1232 | put_io_context(p->io_context); | |
ab516013 | 1233 | bad_fork_cleanup_namespaces: |
444f378b | 1234 | exit_task_namespaces(p); |
1da177e4 LT |
1235 | bad_fork_cleanup_keys: |
1236 | exit_keys(p); | |
1237 | bad_fork_cleanup_mm: | |
1238 | if (p->mm) | |
1239 | mmput(p->mm); | |
1240 | bad_fork_cleanup_signal: | |
6b3934ef | 1241 | cleanup_signal(p); |
1da177e4 | 1242 | bad_fork_cleanup_sighand: |
a7e5328a | 1243 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1244 | bad_fork_cleanup_fs: |
1245 | exit_fs(p); /* blocking */ | |
1246 | bad_fork_cleanup_files: | |
1247 | exit_files(p); /* blocking */ | |
1248 | bad_fork_cleanup_semundo: | |
1249 | exit_sem(p); | |
1250 | bad_fork_cleanup_audit: | |
1251 | audit_free(p); | |
1252 | bad_fork_cleanup_security: | |
1253 | security_task_free(p); | |
1254 | bad_fork_cleanup_policy: | |
1255 | #ifdef CONFIG_NUMA | |
f0be3d32 | 1256 | mpol_put(p->mempolicy); |
b4f48b63 | 1257 | bad_fork_cleanup_cgroup: |
1da177e4 | 1258 | #endif |
b4f48b63 | 1259 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1260 | delayacct_tsk_free(p); |
1da177e4 LT |
1261 | if (p->binfmt) |
1262 | module_put(p->binfmt->module); | |
1263 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1264 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1265 | bad_fork_cleanup_count: |
1266 | put_group_info(p->group_info); | |
1267 | atomic_dec(&p->user->processes); | |
1268 | free_uid(p->user); | |
1269 | bad_fork_free: | |
1270 | free_task(p); | |
fe7d37d1 ON |
1271 | fork_out: |
1272 | return ERR_PTR(retval); | |
1da177e4 LT |
1273 | } |
1274 | ||
6b2fb3c6 | 1275 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1276 | { |
1277 | memset(regs, 0, sizeof(struct pt_regs)); | |
1278 | return regs; | |
1279 | } | |
1280 | ||
9abcf40b | 1281 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1282 | { |
36c8b586 | 1283 | struct task_struct *task; |
1da177e4 LT |
1284 | struct pt_regs regs; |
1285 | ||
30e49c26 | 1286 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
85868995 | 1287 | &init_struct_pid); |
753ca4f3 AM |
1288 | if (!IS_ERR(task)) |
1289 | init_idle(task, cpu); | |
73b9ebfe | 1290 | |
1da177e4 LT |
1291 | return task; |
1292 | } | |
1293 | ||
a39bc516 | 1294 | static int fork_traceflag(unsigned clone_flags) |
1da177e4 LT |
1295 | { |
1296 | if (clone_flags & CLONE_UNTRACED) | |
1297 | return 0; | |
1298 | else if (clone_flags & CLONE_VFORK) { | |
1299 | if (current->ptrace & PT_TRACE_VFORK) | |
1300 | return PTRACE_EVENT_VFORK; | |
1301 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1302 | if (current->ptrace & PT_TRACE_CLONE) | |
1303 | return PTRACE_EVENT_CLONE; | |
1304 | } else if (current->ptrace & PT_TRACE_FORK) | |
1305 | return PTRACE_EVENT_FORK; | |
1306 | ||
1307 | return 0; | |
1308 | } | |
1309 | ||
1310 | /* | |
1311 | * Ok, this is the main fork-routine. | |
1312 | * | |
1313 | * It copies the process, and if successful kick-starts | |
1314 | * it and waits for it to finish using the VM if required. | |
1315 | */ | |
1316 | long do_fork(unsigned long clone_flags, | |
1317 | unsigned long stack_start, | |
1318 | struct pt_regs *regs, | |
1319 | unsigned long stack_size, | |
1320 | int __user *parent_tidptr, | |
1321 | int __user *child_tidptr) | |
1322 | { | |
1323 | struct task_struct *p; | |
1324 | int trace = 0; | |
92476d7f | 1325 | long nr; |
1da177e4 | 1326 | |
bdff746a AM |
1327 | /* |
1328 | * We hope to recycle these flags after 2.6.26 | |
1329 | */ | |
1330 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1331 | static int __read_mostly count = 100; | |
1332 | ||
1333 | if (count > 0 && printk_ratelimit()) { | |
1334 | char comm[TASK_COMM_LEN]; | |
1335 | ||
1336 | count--; | |
1337 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1338 | "clone flags 0x%lx\n", | |
1339 | get_task_comm(comm, current), | |
1340 | clone_flags & CLONE_STOPPED); | |
1341 | } | |
1342 | } | |
1343 | ||
1da177e4 LT |
1344 | if (unlikely(current->ptrace)) { |
1345 | trace = fork_traceflag (clone_flags); | |
1346 | if (trace) | |
1347 | clone_flags |= CLONE_PTRACE; | |
1348 | } | |
1349 | ||
a6f5e063 | 1350 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
30e49c26 | 1351 | child_tidptr, NULL); |
1da177e4 LT |
1352 | /* |
1353 | * Do this prior waking up the new thread - the thread pointer | |
1354 | * might get invalid after that point, if the thread exits quickly. | |
1355 | */ | |
1356 | if (!IS_ERR(p)) { | |
1357 | struct completion vfork; | |
1358 | ||
6c5f3e7b | 1359 | nr = task_pid_vnr(p); |
30e49c26 PE |
1360 | |
1361 | if (clone_flags & CLONE_PARENT_SETTID) | |
1362 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1363 | |
1da177e4 LT |
1364 | if (clone_flags & CLONE_VFORK) { |
1365 | p->vfork_done = &vfork; | |
1366 | init_completion(&vfork); | |
1367 | } | |
1368 | ||
1369 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1370 | /* | |
1371 | * We'll start up with an immediate SIGSTOP. | |
1372 | */ | |
1373 | sigaddset(&p->pending.signal, SIGSTOP); | |
1374 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1375 | } | |
1376 | ||
1377 | if (!(clone_flags & CLONE_STOPPED)) | |
1378 | wake_up_new_task(p, clone_flags); | |
1379 | else | |
d9ae90ac | 1380 | __set_task_state(p, TASK_STOPPED); |
1da177e4 LT |
1381 | |
1382 | if (unlikely (trace)) { | |
92476d7f | 1383 | current->ptrace_message = nr; |
1da177e4 LT |
1384 | ptrace_notify ((trace << 8) | SIGTRAP); |
1385 | } | |
1386 | ||
1387 | if (clone_flags & CLONE_VFORK) { | |
ba96a0c8 | 1388 | freezer_do_not_count(); |
1da177e4 | 1389 | wait_for_completion(&vfork); |
ba96a0c8 | 1390 | freezer_count(); |
9f59ce5d CE |
1391 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) { |
1392 | current->ptrace_message = nr; | |
1da177e4 | 1393 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); |
9f59ce5d | 1394 | } |
1da177e4 LT |
1395 | } |
1396 | } else { | |
92476d7f | 1397 | nr = PTR_ERR(p); |
1da177e4 | 1398 | } |
92476d7f | 1399 | return nr; |
1da177e4 LT |
1400 | } |
1401 | ||
5fd63b30 RT |
1402 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1403 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1404 | #endif | |
1405 | ||
4ba9b9d0 | 1406 | static void sighand_ctor(struct kmem_cache *cachep, void *data) |
aa1757f9 ON |
1407 | { |
1408 | struct sighand_struct *sighand = data; | |
1409 | ||
a35afb83 | 1410 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1411 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1412 | } |
1413 | ||
1da177e4 LT |
1414 | void __init proc_caches_init(void) |
1415 | { | |
1416 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1417 | sizeof(struct sighand_struct), 0, | |
aa1757f9 | 1418 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
20c2df83 | 1419 | sighand_ctor); |
1da177e4 LT |
1420 | signal_cachep = kmem_cache_create("signal_cache", |
1421 | sizeof(struct signal_struct), 0, | |
20c2df83 PM |
1422 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1423 | files_cachep = kmem_cache_create("files_cache", | |
1da177e4 | 1424 | sizeof(struct files_struct), 0, |
20c2df83 PM |
1425 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1426 | fs_cachep = kmem_cache_create("fs_cache", | |
1da177e4 | 1427 | sizeof(struct fs_struct), 0, |
20c2df83 | 1428 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1429 | vm_area_cachep = kmem_cache_create("vm_area_struct", |
1430 | sizeof(struct vm_area_struct), 0, | |
20c2df83 | 1431 | SLAB_PANIC, NULL); |
1da177e4 | 1432 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1433 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
20c2df83 | 1434 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 1435 | } |
cf2e340f | 1436 | |
cf2e340f JD |
1437 | /* |
1438 | * Check constraints on flags passed to the unshare system call and | |
1439 | * force unsharing of additional process context as appropriate. | |
1440 | */ | |
a39bc516 | 1441 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1442 | { |
1443 | /* | |
1444 | * If unsharing a thread from a thread group, must also | |
1445 | * unshare vm. | |
1446 | */ | |
1447 | if (*flags_ptr & CLONE_THREAD) | |
1448 | *flags_ptr |= CLONE_VM; | |
1449 | ||
1450 | /* | |
1451 | * If unsharing vm, must also unshare signal handlers. | |
1452 | */ | |
1453 | if (*flags_ptr & CLONE_VM) | |
1454 | *flags_ptr |= CLONE_SIGHAND; | |
1455 | ||
1456 | /* | |
1457 | * If unsharing signal handlers and the task was created | |
1458 | * using CLONE_THREAD, then must unshare the thread | |
1459 | */ | |
1460 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1461 | (atomic_read(¤t->signal->count) > 1)) | |
1462 | *flags_ptr |= CLONE_THREAD; | |
1463 | ||
1464 | /* | |
1465 | * If unsharing namespace, must also unshare filesystem information. | |
1466 | */ | |
1467 | if (*flags_ptr & CLONE_NEWNS) | |
1468 | *flags_ptr |= CLONE_FS; | |
1469 | } | |
1470 | ||
1471 | /* | |
1472 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1473 | */ | |
1474 | static int unshare_thread(unsigned long unshare_flags) | |
1475 | { | |
1476 | if (unshare_flags & CLONE_THREAD) | |
1477 | return -EINVAL; | |
1478 | ||
1479 | return 0; | |
1480 | } | |
1481 | ||
1482 | /* | |
99d1419d | 1483 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1484 | */ |
1485 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1486 | { | |
1487 | struct fs_struct *fs = current->fs; | |
1488 | ||
1489 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1490 | (fs && atomic_read(&fs->count) > 1)) { |
1491 | *new_fsp = __copy_fs_struct(current->fs); | |
1492 | if (!*new_fsp) | |
1493 | return -ENOMEM; | |
1494 | } | |
cf2e340f JD |
1495 | |
1496 | return 0; | |
1497 | } | |
1498 | ||
cf2e340f | 1499 | /* |
dae3c5a0 | 1500 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1501 | */ |
1502 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1503 | { | |
1504 | struct sighand_struct *sigh = current->sighand; | |
1505 | ||
dae3c5a0 | 1506 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1507 | return -EINVAL; |
1508 | else | |
1509 | return 0; | |
1510 | } | |
1511 | ||
1512 | /* | |
a0a7ec30 | 1513 | * Unshare vm if it is being shared |
cf2e340f JD |
1514 | */ |
1515 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1516 | { | |
1517 | struct mm_struct *mm = current->mm; | |
1518 | ||
1519 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1520 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1521 | return -EINVAL; |
a0a7ec30 | 1522 | } |
cf2e340f JD |
1523 | |
1524 | return 0; | |
cf2e340f JD |
1525 | } |
1526 | ||
1527 | /* | |
a016f338 | 1528 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1529 | */ |
1530 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1531 | { | |
1532 | struct files_struct *fd = current->files; | |
a016f338 | 1533 | int error = 0; |
cf2e340f JD |
1534 | |
1535 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1536 | (fd && atomic_read(&fd->count) > 1)) { |
1537 | *new_fdp = dup_fd(fd, &error); | |
1538 | if (!*new_fdp) | |
1539 | return error; | |
1540 | } | |
cf2e340f JD |
1541 | |
1542 | return 0; | |
1543 | } | |
1544 | ||
cf2e340f JD |
1545 | /* |
1546 | * unshare allows a process to 'unshare' part of the process | |
1547 | * context which was originally shared using clone. copy_* | |
1548 | * functions used by do_fork() cannot be used here directly | |
1549 | * because they modify an inactive task_struct that is being | |
1550 | * constructed. Here we are modifying the current, active, | |
1551 | * task_struct. | |
1552 | */ | |
1553 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1554 | { | |
1555 | int err = 0; | |
1556 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1557 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1558 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1559 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1560 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1561 | int do_sysvsem = 0; |
cf2e340f JD |
1562 | |
1563 | check_unshare_flags(&unshare_flags); | |
1564 | ||
06f9d4f9 EB |
1565 | /* Return -EINVAL for all unsupported flags */ |
1566 | err = -EINVAL; | |
1567 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1568 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
9dd776b6 EB |
1569 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER| |
1570 | CLONE_NEWNET)) | |
06f9d4f9 EB |
1571 | goto bad_unshare_out; |
1572 | ||
6013f67f MS |
1573 | /* |
1574 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1575 | * to a new ipc namespace, the semaphore arrays from the old | |
1576 | * namespace are unreachable. | |
1577 | */ | |
1578 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1579 | do_sysvsem = 1; |
cf2e340f JD |
1580 | if ((err = unshare_thread(unshare_flags))) |
1581 | goto bad_unshare_out; | |
1582 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1583 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1584 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1585 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1586 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1587 | goto bad_unshare_cleanup_sigh; | |
1588 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1589 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1590 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1591 | new_fs))) | |
9edff4ab | 1592 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1593 | |
9edff4ab MS |
1594 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1595 | if (do_sysvsem) { | |
1596 | /* | |
1597 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1598 | */ | |
1599 | exit_sem(current); | |
1600 | } | |
ab516013 | 1601 | |
c0b2fc31 | 1602 | if (new_nsproxy) { |
cf7b708c PE |
1603 | switch_task_namespaces(current, new_nsproxy); |
1604 | new_nsproxy = NULL; | |
c0b2fc31 | 1605 | } |
cf2e340f | 1606 | |
cf7b708c PE |
1607 | task_lock(current); |
1608 | ||
cf2e340f JD |
1609 | if (new_fs) { |
1610 | fs = current->fs; | |
1611 | current->fs = new_fs; | |
1612 | new_fs = fs; | |
1613 | } | |
1614 | ||
cf2e340f JD |
1615 | if (new_mm) { |
1616 | mm = current->mm; | |
1617 | active_mm = current->active_mm; | |
1618 | current->mm = new_mm; | |
1619 | current->active_mm = new_mm; | |
1620 | activate_mm(active_mm, new_mm); | |
1621 | new_mm = mm; | |
1622 | } | |
1623 | ||
1624 | if (new_fd) { | |
1625 | fd = current->files; | |
1626 | current->files = new_fd; | |
1627 | new_fd = fd; | |
1628 | } | |
1629 | ||
1630 | task_unlock(current); | |
1631 | } | |
1632 | ||
c0b2fc31 | 1633 | if (new_nsproxy) |
444f378b | 1634 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1635 | |
cf2e340f JD |
1636 | bad_unshare_cleanup_fd: |
1637 | if (new_fd) | |
1638 | put_files_struct(new_fd); | |
1639 | ||
1640 | bad_unshare_cleanup_vm: | |
1641 | if (new_mm) | |
1642 | mmput(new_mm); | |
1643 | ||
1644 | bad_unshare_cleanup_sigh: | |
1645 | if (new_sigh) | |
1646 | if (atomic_dec_and_test(&new_sigh->count)) | |
1647 | kmem_cache_free(sighand_cachep, new_sigh); | |
1648 | ||
cf2e340f JD |
1649 | bad_unshare_cleanup_fs: |
1650 | if (new_fs) | |
1651 | put_fs_struct(new_fs); | |
1652 | ||
1653 | bad_unshare_cleanup_thread: | |
1654 | bad_unshare_out: | |
1655 | return err; | |
1656 | } | |
3b125388 AV |
1657 | |
1658 | /* | |
1659 | * Helper to unshare the files of the current task. | |
1660 | * We don't want to expose copy_files internals to | |
1661 | * the exec layer of the kernel. | |
1662 | */ | |
1663 | ||
1664 | int unshare_files(struct files_struct **displaced) | |
1665 | { | |
1666 | struct task_struct *task = current; | |
50704516 | 1667 | struct files_struct *copy = NULL; |
3b125388 AV |
1668 | int error; |
1669 | ||
1670 | error = unshare_fd(CLONE_FILES, ©); | |
1671 | if (error || !copy) { | |
1672 | *displaced = NULL; | |
1673 | return error; | |
1674 | } | |
1675 | *displaced = task->files; | |
1676 | task_lock(task); | |
1677 | task->files = copy; | |
1678 | task_unlock(task); | |
1679 | return 0; | |
1680 | } |