Commit | Line | Data |
---|---|---|
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> | |
25 | #include <linux/key.h> | |
26 | #include <linux/binfmts.h> | |
27 | #include <linux/mman.h> | |
28 | #include <linux/fs.h> | |
ab516013 | 29 | #include <linux/nsproxy.h> |
c59ede7b | 30 | #include <linux/capability.h> |
1da177e4 | 31 | #include <linux/cpu.h> |
b4f48b63 | 32 | #include <linux/cgroup.h> |
1da177e4 LT |
33 | #include <linux/security.h> |
34 | #include <linux/swap.h> | |
35 | #include <linux/syscalls.h> | |
36 | #include <linux/jiffies.h> | |
37 | #include <linux/futex.h> | |
7c3ab738 | 38 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 39 | #include <linux/rcupdate.h> |
1da177e4 LT |
40 | #include <linux/ptrace.h> |
41 | #include <linux/mount.h> | |
42 | #include <linux/audit.h> | |
78fb7466 | 43 | #include <linux/memcontrol.h> |
1da177e4 LT |
44 | #include <linux/profile.h> |
45 | #include <linux/rmap.h> | |
46 | #include <linux/acct.h> | |
8f0ab514 | 47 | #include <linux/tsacct_kern.h> |
9f46080c | 48 | #include <linux/cn_proc.h> |
ba96a0c8 | 49 | #include <linux/freezer.h> |
ca74e92b | 50 | #include <linux/delayacct.h> |
ad4ecbcb | 51 | #include <linux/taskstats_kern.h> |
0a425405 | 52 | #include <linux/random.h> |
522ed776 | 53 | #include <linux/tty.h> |
6f4e6433 | 54 | #include <linux/proc_fs.h> |
fd0928df | 55 | #include <linux/blkdev.h> |
1da177e4 LT |
56 | |
57 | #include <asm/pgtable.h> | |
58 | #include <asm/pgalloc.h> | |
59 | #include <asm/uaccess.h> | |
60 | #include <asm/mmu_context.h> | |
61 | #include <asm/cacheflush.h> | |
62 | #include <asm/tlbflush.h> | |
63 | ||
64 | /* | |
65 | * Protected counters by write_lock_irq(&tasklist_lock) | |
66 | */ | |
67 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
68 | int nr_threads; /* The idle threads do not count.. */ | |
69 | ||
70 | int max_threads; /* tunable limit on nr_threads */ | |
71 | ||
72 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
73 | ||
c59923a1 | 74 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
75 | |
76 | int nr_processes(void) | |
77 | { | |
78 | int cpu; | |
79 | int total = 0; | |
80 | ||
81 | for_each_online_cpu(cpu) | |
82 | total += per_cpu(process_counts, cpu); | |
83 | ||
84 | return total; | |
85 | } | |
86 | ||
87 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
88 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
89 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 90 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
91 | #endif |
92 | ||
93 | /* SLAB cache for signal_struct structures (tsk->signal) */ | |
e18b890b | 94 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
95 | |
96 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 97 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
98 | |
99 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 100 | struct kmem_cache *files_cachep; |
1da177e4 LT |
101 | |
102 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 103 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
104 | |
105 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 106 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
107 | |
108 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 109 | static struct kmem_cache *mm_cachep; |
1da177e4 LT |
110 | |
111 | void free_task(struct task_struct *tsk) | |
112 | { | |
3e26c149 | 113 | prop_local_destroy_single(&tsk->dirties); |
f7e4217b | 114 | free_thread_info(tsk->stack); |
23f78d4a | 115 | rt_mutex_debug_task_free(tsk); |
1da177e4 LT |
116 | free_task_struct(tsk); |
117 | } | |
118 | EXPORT_SYMBOL(free_task); | |
119 | ||
158d9ebd | 120 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 121 | { |
270f722d | 122 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
123 | WARN_ON(atomic_read(&tsk->usage)); |
124 | WARN_ON(tsk == current); | |
125 | ||
1da177e4 LT |
126 | security_task_free(tsk); |
127 | free_uid(tsk->user); | |
128 | put_group_info(tsk->group_info); | |
35df17c5 | 129 | delayacct_tsk_free(tsk); |
1da177e4 LT |
130 | |
131 | if (!profile_handoff_task(tsk)) | |
132 | free_task(tsk); | |
133 | } | |
134 | ||
2adee9b3 SS |
135 | /* |
136 | * macro override instead of weak attribute alias, to workaround | |
137 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
138 | */ | |
139 | #ifndef arch_task_cache_init | |
140 | #define arch_task_cache_init() | |
141 | #endif | |
61c4628b | 142 | |
1da177e4 LT |
143 | void __init fork_init(unsigned long mempages) |
144 | { | |
145 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
146 | #ifndef ARCH_MIN_TASKALIGN | |
147 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
148 | #endif | |
149 | /* create a slab on which task_structs can be allocated */ | |
150 | task_struct_cachep = | |
151 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
20c2df83 | 152 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL); |
1da177e4 LT |
153 | #endif |
154 | ||
61c4628b SS |
155 | /* do the arch specific task caches init */ |
156 | arch_task_cache_init(); | |
157 | ||
1da177e4 LT |
158 | /* |
159 | * The default maximum number of threads is set to a safe | |
160 | * value: the thread structures can take up at most half | |
161 | * of memory. | |
162 | */ | |
163 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
164 | ||
165 | /* | |
166 | * we need to allow at least 20 threads to boot a system | |
167 | */ | |
168 | if(max_threads < 20) | |
169 | max_threads = 20; | |
170 | ||
171 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
172 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
173 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
174 | init_task.signal->rlim[RLIMIT_NPROC]; | |
175 | } | |
176 | ||
61c4628b SS |
177 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
178 | struct task_struct *src) | |
179 | { | |
180 | *dst = *src; | |
181 | return 0; | |
182 | } | |
183 | ||
1da177e4 LT |
184 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
185 | { | |
186 | struct task_struct *tsk; | |
187 | struct thread_info *ti; | |
3e26c149 | 188 | int err; |
1da177e4 LT |
189 | |
190 | prepare_to_copy(orig); | |
191 | ||
192 | tsk = alloc_task_struct(); | |
193 | if (!tsk) | |
194 | return NULL; | |
195 | ||
196 | ti = alloc_thread_info(tsk); | |
197 | if (!ti) { | |
198 | free_task_struct(tsk); | |
199 | return NULL; | |
200 | } | |
201 | ||
61c4628b SS |
202 | err = arch_dup_task_struct(tsk, orig); |
203 | if (err) | |
204 | goto out; | |
205 | ||
f7e4217b | 206 | tsk->stack = ti; |
3e26c149 PZ |
207 | |
208 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
209 | if (err) |
210 | goto out; | |
3e26c149 | 211 | |
10ebffde | 212 | setup_thread_stack(tsk, orig); |
1da177e4 | 213 | |
0a425405 AV |
214 | #ifdef CONFIG_CC_STACKPROTECTOR |
215 | tsk->stack_canary = get_random_int(); | |
216 | #endif | |
217 | ||
1da177e4 LT |
218 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
219 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 220 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 221 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 222 | tsk->btrace_seq = 0; |
6c5c9341 | 223 | #endif |
a0aa7f68 | 224 | tsk->splice_pipe = NULL; |
1da177e4 | 225 | return tsk; |
61c4628b SS |
226 | |
227 | out: | |
228 | free_thread_info(ti); | |
229 | free_task_struct(tsk); | |
230 | return NULL; | |
1da177e4 LT |
231 | } |
232 | ||
233 | #ifdef CONFIG_MMU | |
a39bc516 | 234 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 235 | { |
fd3e42fc | 236 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
237 | struct rb_node **rb_link, *rb_parent; |
238 | int retval; | |
239 | unsigned long charge; | |
240 | struct mempolicy *pol; | |
241 | ||
242 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 243 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
244 | /* |
245 | * Not linked in yet - no deadlock potential: | |
246 | */ | |
247 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 248 | |
1da177e4 LT |
249 | mm->locked_vm = 0; |
250 | mm->mmap = NULL; | |
251 | mm->mmap_cache = NULL; | |
252 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 253 | mm->cached_hole_size = ~0UL; |
1da177e4 | 254 | mm->map_count = 0; |
1da177e4 LT |
255 | cpus_clear(mm->cpu_vm_mask); |
256 | mm->mm_rb = RB_ROOT; | |
257 | rb_link = &mm->mm_rb.rb_node; | |
258 | rb_parent = NULL; | |
259 | pprev = &mm->mmap; | |
260 | ||
fd3e42fc | 261 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
262 | struct file *file; |
263 | ||
264 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
265 | long pages = vma_pages(mpnt); |
266 | mm->total_vm -= pages; | |
ab50b8ed | 267 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 268 | -pages); |
1da177e4 LT |
269 | continue; |
270 | } | |
271 | charge = 0; | |
272 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
273 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
274 | if (security_vm_enough_memory(len)) | |
275 | goto fail_nomem; | |
276 | charge = len; | |
277 | } | |
e94b1766 | 278 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
279 | if (!tmp) |
280 | goto fail_nomem; | |
281 | *tmp = *mpnt; | |
846a16bf | 282 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
283 | retval = PTR_ERR(pol); |
284 | if (IS_ERR(pol)) | |
285 | goto fail_nomem_policy; | |
286 | vma_set_policy(tmp, pol); | |
287 | tmp->vm_flags &= ~VM_LOCKED; | |
288 | tmp->vm_mm = mm; | |
289 | tmp->vm_next = NULL; | |
290 | anon_vma_link(tmp); | |
291 | file = tmp->vm_file; | |
292 | if (file) { | |
f3a43f3f | 293 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
294 | get_file(file); |
295 | if (tmp->vm_flags & VM_DENYWRITE) | |
296 | atomic_dec(&inode->i_writecount); | |
23ff4440 | 297 | |
1da177e4 LT |
298 | /* insert tmp into the share list, just after mpnt */ |
299 | spin_lock(&file->f_mapping->i_mmap_lock); | |
300 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
301 | flush_dcache_mmap_lock(file->f_mapping); | |
302 | vma_prio_tree_add(tmp, mpnt); | |
303 | flush_dcache_mmap_unlock(file->f_mapping); | |
304 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
305 | } | |
306 | ||
307 | /* | |
7ee78232 | 308 | * Link in the new vma and copy the page table entries. |
1da177e4 | 309 | */ |
1da177e4 LT |
310 | *pprev = tmp; |
311 | pprev = &tmp->vm_next; | |
312 | ||
313 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
314 | rb_link = &tmp->vm_rb.rb_right; | |
315 | rb_parent = &tmp->vm_rb; | |
316 | ||
317 | mm->map_count++; | |
0b0db14c | 318 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
319 | |
320 | if (tmp->vm_ops && tmp->vm_ops->open) | |
321 | tmp->vm_ops->open(tmp); | |
322 | ||
323 | if (retval) | |
324 | goto out; | |
325 | } | |
d6dd61c8 JF |
326 | /* a new mm has just been created */ |
327 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 328 | retval = 0; |
1da177e4 | 329 | out: |
7ee78232 | 330 | up_write(&mm->mmap_sem); |
fd3e42fc | 331 | flush_tlb_mm(oldmm); |
1da177e4 LT |
332 | up_write(&oldmm->mmap_sem); |
333 | return retval; | |
334 | fail_nomem_policy: | |
335 | kmem_cache_free(vm_area_cachep, tmp); | |
336 | fail_nomem: | |
337 | retval = -ENOMEM; | |
338 | vm_unacct_memory(charge); | |
339 | goto out; | |
340 | } | |
341 | ||
342 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
343 | { | |
344 | mm->pgd = pgd_alloc(mm); | |
345 | if (unlikely(!mm->pgd)) | |
346 | return -ENOMEM; | |
347 | return 0; | |
348 | } | |
349 | ||
350 | static inline void mm_free_pgd(struct mm_struct * mm) | |
351 | { | |
5e541973 | 352 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
353 | } |
354 | #else | |
355 | #define dup_mmap(mm, oldmm) (0) | |
356 | #define mm_alloc_pgd(mm) (0) | |
357 | #define mm_free_pgd(mm) | |
358 | #endif /* CONFIG_MMU */ | |
359 | ||
23ff4440 | 360 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 361 | |
e94b1766 | 362 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
363 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
364 | ||
365 | #include <linux/init_task.h> | |
366 | ||
78fb7466 | 367 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
368 | { |
369 | atomic_set(&mm->mm_users, 1); | |
370 | atomic_set(&mm->mm_count, 1); | |
371 | init_rwsem(&mm->mmap_sem); | |
372 | INIT_LIST_HEAD(&mm->mmlist); | |
3cb4a0bb KH |
373 | mm->flags = (current->mm) ? current->mm->flags |
374 | : MMF_DUMP_FILTER_DEFAULT; | |
1da177e4 LT |
375 | mm->core_waiters = 0; |
376 | mm->nr_ptes = 0; | |
4294621f | 377 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 378 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
379 | spin_lock_init(&mm->page_table_lock); |
380 | rwlock_init(&mm->ioctx_list_lock); | |
381 | mm->ioctx_list = NULL; | |
1da177e4 | 382 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 383 | mm->cached_hole_size = ~0UL; |
cf475ad2 | 384 | mm_init_owner(mm, p); |
1da177e4 LT |
385 | |
386 | if (likely(!mm_alloc_pgd(mm))) { | |
387 | mm->def_flags = 0; | |
388 | return mm; | |
389 | } | |
78fb7466 | 390 | |
1da177e4 LT |
391 | free_mm(mm); |
392 | return NULL; | |
393 | } | |
394 | ||
395 | /* | |
396 | * Allocate and initialize an mm_struct. | |
397 | */ | |
398 | struct mm_struct * mm_alloc(void) | |
399 | { | |
400 | struct mm_struct * mm; | |
401 | ||
402 | mm = allocate_mm(); | |
403 | if (mm) { | |
404 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 405 | mm = mm_init(mm, current); |
1da177e4 LT |
406 | } |
407 | return mm; | |
408 | } | |
409 | ||
410 | /* | |
411 | * Called when the last reference to the mm | |
412 | * is dropped: either by a lazy thread or by | |
413 | * mmput. Free the page directory and the mm. | |
414 | */ | |
7ad5b3a5 | 415 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
416 | { |
417 | BUG_ON(mm == &init_mm); | |
418 | mm_free_pgd(mm); | |
419 | destroy_context(mm); | |
420 | free_mm(mm); | |
421 | } | |
6d4e4c4f | 422 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
423 | |
424 | /* | |
425 | * Decrement the use count and release all resources for an mm. | |
426 | */ | |
427 | void mmput(struct mm_struct *mm) | |
428 | { | |
0ae26f1b AM |
429 | might_sleep(); |
430 | ||
1da177e4 LT |
431 | if (atomic_dec_and_test(&mm->mm_users)) { |
432 | exit_aio(mm); | |
433 | exit_mmap(mm); | |
434 | if (!list_empty(&mm->mmlist)) { | |
435 | spin_lock(&mmlist_lock); | |
436 | list_del(&mm->mmlist); | |
437 | spin_unlock(&mmlist_lock); | |
438 | } | |
439 | put_swap_token(mm); | |
440 | mmdrop(mm); | |
441 | } | |
442 | } | |
443 | EXPORT_SYMBOL_GPL(mmput); | |
444 | ||
445 | /** | |
446 | * get_task_mm - acquire a reference to the task's mm | |
447 | * | |
448 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning | |
449 | * this kernel workthread has transiently adopted a user mm with use_mm, | |
450 | * to do its AIO) is not set and if so returns a reference to it, after | |
451 | * bumping up the use count. User must release the mm via mmput() | |
452 | * after use. Typically used by /proc and ptrace. | |
453 | */ | |
454 | struct mm_struct *get_task_mm(struct task_struct *task) | |
455 | { | |
456 | struct mm_struct *mm; | |
457 | ||
458 | task_lock(task); | |
459 | mm = task->mm; | |
460 | if (mm) { | |
461 | if (task->flags & PF_BORROWED_MM) | |
462 | mm = NULL; | |
463 | else | |
464 | atomic_inc(&mm->mm_users); | |
465 | } | |
466 | task_unlock(task); | |
467 | return mm; | |
468 | } | |
469 | EXPORT_SYMBOL_GPL(get_task_mm); | |
470 | ||
471 | /* Please note the differences between mmput and mm_release. | |
472 | * mmput is called whenever we stop holding onto a mm_struct, | |
473 | * error success whatever. | |
474 | * | |
475 | * mm_release is called after a mm_struct has been removed | |
476 | * from the current process. | |
477 | * | |
478 | * This difference is important for error handling, when we | |
479 | * only half set up a mm_struct for a new process and need to restore | |
480 | * the old one. Because we mmput the new mm_struct before | |
481 | * restoring the old one. . . | |
482 | * Eric Biederman 10 January 1998 | |
483 | */ | |
484 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
485 | { | |
486 | struct completion *vfork_done = tsk->vfork_done; | |
487 | ||
488 | /* Get rid of any cached register state */ | |
489 | deactivate_mm(tsk, mm); | |
490 | ||
491 | /* notify parent sleeping on vfork() */ | |
492 | if (vfork_done) { | |
493 | tsk->vfork_done = NULL; | |
494 | complete(vfork_done); | |
495 | } | |
fec1d011 RM |
496 | |
497 | /* | |
498 | * If we're exiting normally, clear a user-space tid field if | |
499 | * requested. We leave this alone when dying by signal, to leave | |
500 | * the value intact in a core dump, and to save the unnecessary | |
501 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
502 | */ | |
503 | if (tsk->clear_child_tid | |
504 | && !(tsk->flags & PF_SIGNALED) | |
505 | && atomic_read(&mm->mm_users) > 1) { | |
1da177e4 LT |
506 | u32 __user * tidptr = tsk->clear_child_tid; |
507 | tsk->clear_child_tid = NULL; | |
508 | ||
509 | /* | |
510 | * We don't check the error code - if userspace has | |
511 | * not set up a proper pointer then tough luck. | |
512 | */ | |
513 | put_user(0, tidptr); | |
514 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
515 | } | |
516 | } | |
517 | ||
a0a7ec30 JD |
518 | /* |
519 | * Allocate a new mm structure and copy contents from the | |
520 | * mm structure of the passed in task structure. | |
521 | */ | |
402b0862 | 522 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
523 | { |
524 | struct mm_struct *mm, *oldmm = current->mm; | |
525 | int err; | |
526 | ||
527 | if (!oldmm) | |
528 | return NULL; | |
529 | ||
530 | mm = allocate_mm(); | |
531 | if (!mm) | |
532 | goto fail_nomem; | |
533 | ||
534 | memcpy(mm, oldmm, sizeof(*mm)); | |
535 | ||
7602bdf2 AC |
536 | /* Initializing for Swap token stuff */ |
537 | mm->token_priority = 0; | |
538 | mm->last_interval = 0; | |
539 | ||
78fb7466 | 540 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
541 | goto fail_nomem; |
542 | ||
543 | if (init_new_context(tsk, mm)) | |
544 | goto fail_nocontext; | |
545 | ||
546 | err = dup_mmap(mm, oldmm); | |
547 | if (err) | |
548 | goto free_pt; | |
549 | ||
550 | mm->hiwater_rss = get_mm_rss(mm); | |
551 | mm->hiwater_vm = mm->total_vm; | |
552 | ||
553 | return mm; | |
554 | ||
555 | free_pt: | |
556 | mmput(mm); | |
557 | ||
558 | fail_nomem: | |
559 | return NULL; | |
560 | ||
561 | fail_nocontext: | |
562 | /* | |
563 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
564 | * because it calls destroy_context() | |
565 | */ | |
566 | mm_free_pgd(mm); | |
567 | free_mm(mm); | |
568 | return NULL; | |
569 | } | |
570 | ||
1da177e4 LT |
571 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
572 | { | |
573 | struct mm_struct * mm, *oldmm; | |
574 | int retval; | |
575 | ||
576 | tsk->min_flt = tsk->maj_flt = 0; | |
577 | tsk->nvcsw = tsk->nivcsw = 0; | |
578 | ||
579 | tsk->mm = NULL; | |
580 | tsk->active_mm = NULL; | |
581 | ||
582 | /* | |
583 | * Are we cloning a kernel thread? | |
584 | * | |
585 | * We need to steal a active VM for that.. | |
586 | */ | |
587 | oldmm = current->mm; | |
588 | if (!oldmm) | |
589 | return 0; | |
590 | ||
591 | if (clone_flags & CLONE_VM) { | |
592 | atomic_inc(&oldmm->mm_users); | |
593 | mm = oldmm; | |
1da177e4 LT |
594 | goto good_mm; |
595 | } | |
596 | ||
597 | retval = -ENOMEM; | |
a0a7ec30 | 598 | mm = dup_mm(tsk); |
1da177e4 LT |
599 | if (!mm) |
600 | goto fail_nomem; | |
601 | ||
1da177e4 | 602 | good_mm: |
7602bdf2 AC |
603 | /* Initializing for Swap token stuff */ |
604 | mm->token_priority = 0; | |
605 | mm->last_interval = 0; | |
606 | ||
1da177e4 LT |
607 | tsk->mm = mm; |
608 | tsk->active_mm = mm; | |
609 | return 0; | |
610 | ||
1da177e4 LT |
611 | fail_nomem: |
612 | return retval; | |
1da177e4 LT |
613 | } |
614 | ||
a39bc516 | 615 | static struct fs_struct *__copy_fs_struct(struct fs_struct *old) |
1da177e4 LT |
616 | { |
617 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
618 | /* We don't need to lock fs - think why ;-) */ | |
619 | if (fs) { | |
620 | atomic_set(&fs->count, 1); | |
621 | rwlock_init(&fs->lock); | |
622 | fs->umask = old->umask; | |
623 | read_lock(&old->lock); | |
6ac08c39 JB |
624 | fs->root = old->root; |
625 | path_get(&old->root); | |
626 | fs->pwd = old->pwd; | |
627 | path_get(&old->pwd); | |
628 | if (old->altroot.dentry) { | |
629 | fs->altroot = old->altroot; | |
630 | path_get(&old->altroot); | |
1da177e4 | 631 | } else { |
6ac08c39 JB |
632 | fs->altroot.mnt = NULL; |
633 | fs->altroot.dentry = NULL; | |
1da177e4 LT |
634 | } |
635 | read_unlock(&old->lock); | |
636 | } | |
637 | return fs; | |
638 | } | |
639 | ||
640 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
641 | { | |
642 | return __copy_fs_struct(old); | |
643 | } | |
644 | ||
645 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
646 | ||
a39bc516 | 647 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
648 | { |
649 | if (clone_flags & CLONE_FS) { | |
650 | atomic_inc(¤t->fs->count); | |
651 | return 0; | |
652 | } | |
653 | tsk->fs = __copy_fs_struct(current->fs); | |
654 | if (!tsk->fs) | |
655 | return -ENOMEM; | |
656 | return 0; | |
657 | } | |
658 | ||
ab2af1f5 | 659 | static int count_open_files(struct fdtable *fdt) |
1da177e4 | 660 | { |
bbea9f69 | 661 | int size = fdt->max_fds; |
1da177e4 LT |
662 | int i; |
663 | ||
664 | /* Find the last open fd */ | |
665 | for (i = size/(8*sizeof(long)); i > 0; ) { | |
badf1662 | 666 | if (fdt->open_fds->fds_bits[--i]) |
1da177e4 LT |
667 | break; |
668 | } | |
669 | i = (i+1) * 8 * sizeof(long); | |
670 | return i; | |
671 | } | |
672 | ||
badf1662 DS |
673 | static struct files_struct *alloc_files(void) |
674 | { | |
675 | struct files_struct *newf; | |
676 | struct fdtable *fdt; | |
677 | ||
e94b1766 | 678 | newf = kmem_cache_alloc(files_cachep, GFP_KERNEL); |
badf1662 DS |
679 | if (!newf) |
680 | goto out; | |
681 | ||
682 | atomic_set(&newf->count, 1); | |
683 | ||
684 | spin_lock_init(&newf->file_lock); | |
0c9e63fd | 685 | newf->next_fd = 0; |
ab2af1f5 | 686 | fdt = &newf->fdtab; |
badf1662 | 687 | fdt->max_fds = NR_OPEN_DEFAULT; |
0c9e63fd ED |
688 | fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init; |
689 | fdt->open_fds = (fd_set *)&newf->open_fds_init; | |
badf1662 | 690 | fdt->fd = &newf->fd_array[0]; |
ab2af1f5 | 691 | INIT_RCU_HEAD(&fdt->rcu); |
ab2af1f5 DS |
692 | fdt->next = NULL; |
693 | rcu_assign_pointer(newf->fdt, fdt); | |
badf1662 DS |
694 | out: |
695 | return newf; | |
696 | } | |
697 | ||
a016f338 JD |
698 | /* |
699 | * Allocate a new files structure and copy contents from the | |
700 | * passed in files structure. | |
6e667260 | 701 | * errorp will be valid only when the returned files_struct is NULL. |
a016f338 JD |
702 | */ |
703 | static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) | |
1da177e4 | 704 | { |
a016f338 | 705 | struct files_struct *newf; |
1da177e4 | 706 | struct file **old_fds, **new_fds; |
bbea9f69 | 707 | int open_files, size, i; |
badf1662 | 708 | struct fdtable *old_fdt, *new_fdt; |
1da177e4 | 709 | |
6e667260 | 710 | *errorp = -ENOMEM; |
badf1662 DS |
711 | newf = alloc_files(); |
712 | if (!newf) | |
1da177e4 LT |
713 | goto out; |
714 | ||
1da177e4 | 715 | spin_lock(&oldf->file_lock); |
badf1662 DS |
716 | old_fdt = files_fdtable(oldf); |
717 | new_fdt = files_fdtable(newf); | |
ab2af1f5 | 718 | open_files = count_open_files(old_fdt); |
1da177e4 LT |
719 | |
720 | /* | |
bbea9f69 VL |
721 | * Check whether we need to allocate a larger fd array and fd set. |
722 | * Note: we're not a clone task, so the open count won't change. | |
1da177e4 | 723 | */ |
badf1662 DS |
724 | if (open_files > new_fdt->max_fds) { |
725 | new_fdt->max_fds = 0; | |
1da177e4 LT |
726 | spin_unlock(&oldf->file_lock); |
727 | spin_lock(&newf->file_lock); | |
a016f338 | 728 | *errorp = expand_files(newf, open_files-1); |
1da177e4 | 729 | spin_unlock(&newf->file_lock); |
a016f338 | 730 | if (*errorp < 0) |
1da177e4 | 731 | goto out_release; |
ab2af1f5 DS |
732 | new_fdt = files_fdtable(newf); |
733 | /* | |
734 | * Reacquire the oldf lock and a pointer to its fd table | |
735 | * who knows it may have a new bigger fd table. We need | |
736 | * the latest pointer. | |
737 | */ | |
1da177e4 | 738 | spin_lock(&oldf->file_lock); |
ab2af1f5 | 739 | old_fdt = files_fdtable(oldf); |
1da177e4 LT |
740 | } |
741 | ||
badf1662 DS |
742 | old_fds = old_fdt->fd; |
743 | new_fds = new_fdt->fd; | |
1da177e4 | 744 | |
f3d19c90 VL |
745 | memcpy(new_fdt->open_fds->fds_bits, |
746 | old_fdt->open_fds->fds_bits, open_files/8); | |
747 | memcpy(new_fdt->close_on_exec->fds_bits, | |
748 | old_fdt->close_on_exec->fds_bits, open_files/8); | |
1da177e4 LT |
749 | |
750 | for (i = open_files; i != 0; i--) { | |
751 | struct file *f = *old_fds++; | |
752 | if (f) { | |
753 | get_file(f); | |
754 | } else { | |
755 | /* | |
756 | * The fd may be claimed in the fd bitmap but not yet | |
757 | * instantiated in the files array if a sibling thread | |
758 | * is partway through open(). So make sure that this | |
759 | * fd is available to the new process. | |
760 | */ | |
badf1662 | 761 | FD_CLR(open_files - i, new_fdt->open_fds); |
1da177e4 | 762 | } |
ab2af1f5 | 763 | rcu_assign_pointer(*new_fds++, f); |
1da177e4 LT |
764 | } |
765 | spin_unlock(&oldf->file_lock); | |
766 | ||
767 | /* compute the remainder to be cleared */ | |
badf1662 | 768 | size = (new_fdt->max_fds - open_files) * sizeof(struct file *); |
1da177e4 | 769 | |
23ff4440 DW |
770 | /* This is long word aligned thus could use a optimized version */ |
771 | memset(new_fds, 0, size); | |
1da177e4 | 772 | |
bbea9f69 VL |
773 | if (new_fdt->max_fds > open_files) { |
774 | int left = (new_fdt->max_fds-open_files)/8; | |
1da177e4 LT |
775 | int start = open_files / (8 * sizeof(unsigned long)); |
776 | ||
badf1662 DS |
777 | memset(&new_fdt->open_fds->fds_bits[start], 0, left); |
778 | memset(&new_fdt->close_on_exec->fds_bits[start], 0, left); | |
1da177e4 LT |
779 | } |
780 | ||
a016f338 | 781 | return newf; |
1da177e4 LT |
782 | |
783 | out_release: | |
1da177e4 | 784 | kmem_cache_free(files_cachep, newf); |
f3d19c90 | 785 | out: |
42862298 | 786 | return NULL; |
1da177e4 LT |
787 | } |
788 | ||
a016f338 JD |
789 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
790 | { | |
791 | struct files_struct *oldf, *newf; | |
792 | int error = 0; | |
793 | ||
794 | /* | |
795 | * A background process may not have any files ... | |
796 | */ | |
797 | oldf = current->files; | |
798 | if (!oldf) | |
799 | goto out; | |
800 | ||
801 | if (clone_flags & CLONE_FILES) { | |
802 | atomic_inc(&oldf->count); | |
803 | goto out; | |
804 | } | |
805 | ||
a016f338 JD |
806 | newf = dup_fd(oldf, &error); |
807 | if (!newf) | |
808 | goto out; | |
809 | ||
810 | tsk->files = newf; | |
811 | error = 0; | |
812 | out: | |
813 | return error; | |
814 | } | |
815 | ||
fadad878 | 816 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
817 | { |
818 | #ifdef CONFIG_BLOCK | |
819 | struct io_context *ioc = current->io_context; | |
820 | ||
821 | if (!ioc) | |
822 | return 0; | |
fadad878 JA |
823 | /* |
824 | * Share io context with parent, if CLONE_IO is set | |
825 | */ | |
826 | if (clone_flags & CLONE_IO) { | |
827 | tsk->io_context = ioc_task_link(ioc); | |
828 | if (unlikely(!tsk->io_context)) | |
829 | return -ENOMEM; | |
830 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
831 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
832 | if (unlikely(!tsk->io_context)) | |
833 | return -ENOMEM; | |
834 | ||
fd0928df JA |
835 | tsk->io_context->ioprio = ioc->ioprio; |
836 | } | |
837 | #endif | |
838 | return 0; | |
839 | } | |
840 | ||
a39bc516 | 841 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
842 | { |
843 | struct sighand_struct *sig; | |
844 | ||
845 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
846 | atomic_inc(¤t->sighand->count); | |
847 | return 0; | |
848 | } | |
849 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 850 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
851 | if (!sig) |
852 | return -ENOMEM; | |
1da177e4 LT |
853 | atomic_set(&sig->count, 1); |
854 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
855 | return 0; | |
856 | } | |
857 | ||
a7e5328a | 858 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 859 | { |
c81addc9 ON |
860 | if (atomic_dec_and_test(&sighand->count)) |
861 | kmem_cache_free(sighand_cachep, sighand); | |
862 | } | |
863 | ||
a39bc516 | 864 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
865 | { |
866 | struct signal_struct *sig; | |
867 | int ret; | |
868 | ||
869 | if (clone_flags & CLONE_THREAD) { | |
870 | atomic_inc(¤t->signal->count); | |
871 | atomic_inc(¤t->signal->live); | |
872 | return 0; | |
873 | } | |
874 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
875 | tsk->signal = sig; | |
876 | if (!sig) | |
877 | return -ENOMEM; | |
878 | ||
879 | ret = copy_thread_group_keys(tsk); | |
880 | if (ret < 0) { | |
881 | kmem_cache_free(signal_cachep, sig); | |
882 | return ret; | |
883 | } | |
884 | ||
885 | atomic_set(&sig->count, 1); | |
886 | atomic_set(&sig->live, 1); | |
887 | init_waitqueue_head(&sig->wait_chldexit); | |
888 | sig->flags = 0; | |
889 | sig->group_exit_code = 0; | |
890 | sig->group_exit_task = NULL; | |
891 | sig->group_stop_count = 0; | |
892 | sig->curr_target = NULL; | |
893 | init_sigpending(&sig->shared_pending); | |
894 | INIT_LIST_HEAD(&sig->posix_timers); | |
895 | ||
c9cb2e3d | 896 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
2ff678b8 | 897 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 898 | sig->real_timer.function = it_real_fn; |
1da177e4 LT |
899 | |
900 | sig->it_virt_expires = cputime_zero; | |
901 | sig->it_virt_incr = cputime_zero; | |
902 | sig->it_prof_expires = cputime_zero; | |
903 | sig->it_prof_incr = cputime_zero; | |
904 | ||
1da177e4 | 905 | sig->leader = 0; /* session leadership doesn't inherit */ |
ab521dc0 | 906 | sig->tty_old_pgrp = NULL; |
1da177e4 LT |
907 | |
908 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
9ac52315 LV |
909 | sig->gtime = cputime_zero; |
910 | sig->cgtime = cputime_zero; | |
1da177e4 LT |
911 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
912 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
6eaeeaba | 913 | sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; |
172ba844 | 914 | sig->sum_sched_runtime = 0; |
1da177e4 LT |
915 | INIT_LIST_HEAD(&sig->cpu_timers[0]); |
916 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
917 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
ad4ecbcb | 918 | taskstats_tgid_init(sig); |
1da177e4 LT |
919 | |
920 | task_lock(current->group_leader); | |
921 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
922 | task_unlock(current->group_leader); | |
923 | ||
924 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
925 | /* | |
926 | * New sole thread in the process gets an expiry time | |
927 | * of the whole CPU time limit. | |
928 | */ | |
929 | tsk->it_prof_expires = | |
930 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
931 | } | |
0e464814 | 932 | acct_init_pacct(&sig->pacct); |
1da177e4 | 933 | |
522ed776 MT |
934 | tty_audit_fork(sig); |
935 | ||
1da177e4 LT |
936 | return 0; |
937 | } | |
938 | ||
6b3934ef ON |
939 | void __cleanup_signal(struct signal_struct *sig) |
940 | { | |
941 | exit_thread_group_keys(sig); | |
942 | kmem_cache_free(signal_cachep, sig); | |
943 | } | |
944 | ||
a39bc516 | 945 | static void cleanup_signal(struct task_struct *tsk) |
6b3934ef ON |
946 | { |
947 | struct signal_struct *sig = tsk->signal; | |
948 | ||
949 | atomic_dec(&sig->live); | |
950 | ||
951 | if (atomic_dec_and_test(&sig->count)) | |
952 | __cleanup_signal(sig); | |
953 | } | |
954 | ||
a39bc516 | 955 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
956 | { |
957 | unsigned long new_flags = p->flags; | |
958 | ||
83144186 | 959 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 LT |
960 | new_flags |= PF_FORKNOEXEC; |
961 | if (!(clone_flags & CLONE_PTRACE)) | |
962 | p->ptrace = 0; | |
963 | p->flags = new_flags; | |
2e131895 | 964 | clear_freeze_flag(p); |
1da177e4 LT |
965 | } |
966 | ||
967 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
968 | { | |
969 | current->clear_child_tid = tidptr; | |
970 | ||
b488893a | 971 | return task_pid_vnr(current); |
1da177e4 LT |
972 | } |
973 | ||
a39bc516 | 974 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 975 | { |
23f78d4a | 976 | spin_lock_init(&p->pi_lock); |
e29e175b | 977 | #ifdef CONFIG_RT_MUTEXES |
23f78d4a IM |
978 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
979 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
980 | #endif |
981 | } | |
982 | ||
cf475ad2 BS |
983 | #ifdef CONFIG_MM_OWNER |
984 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
985 | { | |
986 | mm->owner = p; | |
987 | } | |
988 | #endif /* CONFIG_MM_OWNER */ | |
989 | ||
1da177e4 LT |
990 | /* |
991 | * This creates a new process as a copy of the old one, | |
992 | * but does not actually start it yet. | |
993 | * | |
994 | * It copies the registers, and all the appropriate | |
995 | * parts of the process environment (as per the clone | |
996 | * flags). The actual kick-off is left to the caller. | |
997 | */ | |
36c8b586 IM |
998 | static struct task_struct *copy_process(unsigned long clone_flags, |
999 | unsigned long stack_start, | |
1000 | struct pt_regs *regs, | |
1001 | unsigned long stack_size, | |
36c8b586 | 1002 | int __user *child_tidptr, |
85868995 | 1003 | struct pid *pid) |
1da177e4 LT |
1004 | { |
1005 | int retval; | |
a24efe62 | 1006 | struct task_struct *p; |
b4f48b63 | 1007 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
1008 | |
1009 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
1010 | return ERR_PTR(-EINVAL); | |
1011 | ||
1012 | /* | |
1013 | * Thread groups must share signals as well, and detached threads | |
1014 | * can only be started up within the thread group. | |
1015 | */ | |
1016 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
1017 | return ERR_PTR(-EINVAL); | |
1018 | ||
1019 | /* | |
1020 | * Shared signal handlers imply shared VM. By way of the above, | |
1021 | * thread groups also imply shared VM. Blocking this case allows | |
1022 | * for various simplifications in other code. | |
1023 | */ | |
1024 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
1025 | return ERR_PTR(-EINVAL); | |
1026 | ||
1027 | retval = security_task_create(clone_flags); | |
1028 | if (retval) | |
1029 | goto fork_out; | |
1030 | ||
1031 | retval = -ENOMEM; | |
1032 | p = dup_task_struct(current); | |
1033 | if (!p) | |
1034 | goto fork_out; | |
1035 | ||
bea493a0 PZ |
1036 | rt_mutex_init_task(p); |
1037 | ||
de30a2b3 IM |
1038 | #ifdef CONFIG_TRACE_IRQFLAGS |
1039 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); | |
1040 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
1041 | #endif | |
1da177e4 LT |
1042 | retval = -EAGAIN; |
1043 | if (atomic_read(&p->user->processes) >= | |
1044 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
1045 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
acce292c | 1046 | p->user != current->nsproxy->user_ns->root_user) |
1da177e4 LT |
1047 | goto bad_fork_free; |
1048 | } | |
1049 | ||
1050 | atomic_inc(&p->user->__count); | |
1051 | atomic_inc(&p->user->processes); | |
1052 | get_group_info(p->group_info); | |
1053 | ||
1054 | /* | |
1055 | * If multiple threads are within copy_process(), then this check | |
1056 | * triggers too late. This doesn't hurt, the check is only there | |
1057 | * to stop root fork bombs. | |
1058 | */ | |
1059 | if (nr_threads >= max_threads) | |
1060 | goto bad_fork_cleanup_count; | |
1061 | ||
a1261f54 | 1062 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1063 | goto bad_fork_cleanup_count; |
1064 | ||
1065 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
1066 | goto bad_fork_cleanup_put_domain; | |
1067 | ||
1068 | p->did_exec = 0; | |
ca74e92b | 1069 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 1070 | copy_flags(clone_flags, p); |
1da177e4 LT |
1071 | INIT_LIST_HEAD(&p->children); |
1072 | INIT_LIST_HEAD(&p->sibling); | |
e260be67 PM |
1073 | #ifdef CONFIG_PREEMPT_RCU |
1074 | p->rcu_read_lock_nesting = 0; | |
1075 | p->rcu_flipctr_idx = 0; | |
1076 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1da177e4 LT |
1077 | p->vfork_done = NULL; |
1078 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
1079 | |
1080 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
1081 | init_sigpending(&p->pending); | |
1082 | ||
1083 | p->utime = cputime_zero; | |
1084 | p->stime = cputime_zero; | |
9ac52315 | 1085 | p->gtime = cputime_zero; |
c66f08be MN |
1086 | p->utimescaled = cputime_zero; |
1087 | p->stimescaled = cputime_zero; | |
73a2bcb0 | 1088 | p->prev_utime = cputime_zero; |
9301899b | 1089 | p->prev_stime = cputime_zero; |
172ba844 | 1090 | |
82a1fcb9 IM |
1091 | #ifdef CONFIG_DETECT_SOFTLOCKUP |
1092 | p->last_switch_count = 0; | |
1093 | p->last_switch_timestamp = 0; | |
1094 | #endif | |
1095 | ||
4b98d11b | 1096 | #ifdef CONFIG_TASK_XACCT |
1da177e4 LT |
1097 | p->rchar = 0; /* I/O counter: bytes read */ |
1098 | p->wchar = 0; /* I/O counter: bytes written */ | |
1099 | p->syscr = 0; /* I/O counter: read syscalls */ | |
1100 | p->syscw = 0; /* I/O counter: write syscalls */ | |
4b98d11b | 1101 | #endif |
7c3ab738 | 1102 | task_io_accounting_init(p); |
1da177e4 LT |
1103 | acct_clear_integrals(p); |
1104 | ||
23ff4440 | 1105 | p->it_virt_expires = cputime_zero; |
1da177e4 | 1106 | p->it_prof_expires = cputime_zero; |
23ff4440 DW |
1107 | p->it_sched_expires = 0; |
1108 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1109 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1110 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1da177e4 LT |
1111 | |
1112 | p->lock_depth = -1; /* -1 = no lock */ | |
1113 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1114 | p->real_start_time = p->start_time; |
1115 | monotonic_to_bootbased(&p->real_start_time); | |
57c521ce | 1116 | #ifdef CONFIG_SECURITY |
1da177e4 | 1117 | p->security = NULL; |
57c521ce | 1118 | #endif |
3b7391de | 1119 | p->cap_bset = current->cap_bset; |
1da177e4 | 1120 | p->io_context = NULL; |
1da177e4 | 1121 | p->audit_context = NULL; |
b4f48b63 | 1122 | cgroup_fork(p); |
1da177e4 | 1123 | #ifdef CONFIG_NUMA |
846a16bf | 1124 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1125 | if (IS_ERR(p->mempolicy)) { |
1126 | retval = PTR_ERR(p->mempolicy); | |
1127 | p->mempolicy = NULL; | |
b4f48b63 | 1128 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1129 | } |
c61afb18 | 1130 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1131 | #endif |
de30a2b3 IM |
1132 | #ifdef CONFIG_TRACE_IRQFLAGS |
1133 | p->irq_events = 0; | |
b36e4758 RK |
1134 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1135 | p->hardirqs_enabled = 1; | |
1136 | #else | |
de30a2b3 | 1137 | p->hardirqs_enabled = 0; |
b36e4758 | 1138 | #endif |
de30a2b3 IM |
1139 | p->hardirq_enable_ip = 0; |
1140 | p->hardirq_enable_event = 0; | |
1141 | p->hardirq_disable_ip = _THIS_IP_; | |
1142 | p->hardirq_disable_event = 0; | |
1143 | p->softirqs_enabled = 1; | |
1144 | p->softirq_enable_ip = _THIS_IP_; | |
1145 | p->softirq_enable_event = 0; | |
1146 | p->softirq_disable_ip = 0; | |
1147 | p->softirq_disable_event = 0; | |
1148 | p->hardirq_context = 0; | |
1149 | p->softirq_context = 0; | |
1150 | #endif | |
fbb9ce95 IM |
1151 | #ifdef CONFIG_LOCKDEP |
1152 | p->lockdep_depth = 0; /* no locks held yet */ | |
1153 | p->curr_chain_key = 0; | |
1154 | p->lockdep_recursion = 0; | |
1155 | #endif | |
1da177e4 | 1156 | |
408894ee IM |
1157 | #ifdef CONFIG_DEBUG_MUTEXES |
1158 | p->blocked_on = NULL; /* not blocked yet */ | |
1159 | #endif | |
1160 | ||
3c90e6e9 SV |
1161 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1162 | sched_fork(p, clone_flags); | |
1163 | ||
1da177e4 LT |
1164 | if ((retval = security_task_alloc(p))) |
1165 | goto bad_fork_cleanup_policy; | |
1166 | if ((retval = audit_alloc(p))) | |
1167 | goto bad_fork_cleanup_security; | |
1168 | /* copy all the process information */ | |
1169 | if ((retval = copy_semundo(clone_flags, p))) | |
1170 | goto bad_fork_cleanup_audit; | |
1171 | if ((retval = copy_files(clone_flags, p))) | |
1172 | goto bad_fork_cleanup_semundo; | |
1173 | if ((retval = copy_fs(clone_flags, p))) | |
1174 | goto bad_fork_cleanup_files; | |
1175 | if ((retval = copy_sighand(clone_flags, p))) | |
1176 | goto bad_fork_cleanup_fs; | |
1177 | if ((retval = copy_signal(clone_flags, p))) | |
1178 | goto bad_fork_cleanup_sighand; | |
1179 | if ((retval = copy_mm(clone_flags, p))) | |
1180 | goto bad_fork_cleanup_signal; | |
1181 | if ((retval = copy_keys(clone_flags, p))) | |
1182 | goto bad_fork_cleanup_mm; | |
ab516013 | 1183 | if ((retval = copy_namespaces(clone_flags, p))) |
1da177e4 | 1184 | goto bad_fork_cleanup_keys; |
fadad878 | 1185 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1186 | goto bad_fork_cleanup_namespaces; |
1da177e4 LT |
1187 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); |
1188 | if (retval) | |
fd0928df | 1189 | goto bad_fork_cleanup_io; |
1da177e4 | 1190 | |
425fb2b4 PE |
1191 | if (pid != &init_struct_pid) { |
1192 | retval = -ENOMEM; | |
1193 | pid = alloc_pid(task_active_pid_ns(p)); | |
1194 | if (!pid) | |
fd0928df | 1195 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1196 | |
1197 | if (clone_flags & CLONE_NEWPID) { | |
1198 | retval = pid_ns_prepare_proc(task_active_pid_ns(p)); | |
1199 | if (retval < 0) | |
1200 | goto bad_fork_free_pid; | |
1201 | } | |
425fb2b4 PE |
1202 | } |
1203 | ||
1204 | p->pid = pid_nr(pid); | |
1205 | p->tgid = p->pid; | |
1206 | if (clone_flags & CLONE_THREAD) | |
1207 | p->tgid = current->tgid; | |
1208 | ||
1da177e4 LT |
1209 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1210 | /* | |
1211 | * Clear TID on mm_release()? | |
1212 | */ | |
1213 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1214 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1215 | p->robust_list = NULL; |
1216 | #ifdef CONFIG_COMPAT | |
1217 | p->compat_robust_list = NULL; | |
1218 | #endif | |
c87e2837 IM |
1219 | INIT_LIST_HEAD(&p->pi_state_list); |
1220 | p->pi_state_cache = NULL; | |
42b2dd0a | 1221 | #endif |
f9a3879a GM |
1222 | /* |
1223 | * sigaltstack should be cleared when sharing the same VM | |
1224 | */ | |
1225 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1226 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1227 | ||
1da177e4 LT |
1228 | /* |
1229 | * Syscall tracing should be turned off in the child regardless | |
1230 | * of CLONE_PTRACE. | |
1231 | */ | |
1232 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1233 | #ifdef TIF_SYSCALL_EMU |
1234 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1235 | #endif | |
9745512c | 1236 | clear_all_latency_tracing(p); |
1da177e4 LT |
1237 | |
1238 | /* Our parent execution domain becomes current domain | |
1239 | These must match for thread signalling to apply */ | |
1da177e4 LT |
1240 | p->parent_exec_id = p->self_exec_id; |
1241 | ||
1242 | /* ok, now we should be set up.. */ | |
1243 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1244 | p->pdeath_signal = 0; | |
1245 | p->exit_state = 0; | |
1246 | ||
1da177e4 LT |
1247 | /* |
1248 | * Ok, make it visible to the rest of the system. | |
1249 | * We dont wake it up yet. | |
1250 | */ | |
1251 | p->group_leader = p; | |
47e65328 | 1252 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 LT |
1253 | INIT_LIST_HEAD(&p->ptrace_children); |
1254 | INIT_LIST_HEAD(&p->ptrace_list); | |
1255 | ||
b4f48b63 PM |
1256 | /* Now that the task is set up, run cgroup callbacks if |
1257 | * necessary. We need to run them before the task is visible | |
1258 | * on the tasklist. */ | |
1259 | cgroup_fork_callbacks(p); | |
1260 | cgroup_callbacks_done = 1; | |
1261 | ||
1da177e4 LT |
1262 | /* Need tasklist lock for parent etc handling! */ |
1263 | write_lock_irq(&tasklist_lock); | |
1264 | ||
1265 | /* | |
476d139c NP |
1266 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1267 | * not be changed, nor will its assigned CPU. | |
1268 | * | |
1269 | * The cpus_allowed mask of the parent may have changed after it was | |
1270 | * copied first time - so re-copy it here, then check the child's CPU | |
1271 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1272 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1273 | */ |
1274 | p->cpus_allowed = current->cpus_allowed; | |
6f505b16 | 1275 | p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed; |
26ff6ad9 SV |
1276 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1277 | !cpu_online(task_cpu(p)))) | |
476d139c | 1278 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1279 | |
1da177e4 LT |
1280 | /* CLONE_PARENT re-uses the old parent */ |
1281 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1282 | p->real_parent = current->real_parent; | |
1283 | else | |
1284 | p->real_parent = current; | |
1285 | p->parent = p->real_parent; | |
1286 | ||
3f17da69 | 1287 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1288 | |
1289 | /* | |
1290 | * Process group and session signals need to be delivered to just the | |
1291 | * parent before the fork or both the parent and the child after the | |
1292 | * fork. Restart if a signal comes in before we add the new process to | |
1293 | * it's process group. | |
1294 | * A fatal signal pending means that current will exit, so the new | |
1295 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1296 | */ | |
23ff4440 | 1297 | recalc_sigpending(); |
4a2c7a78 ON |
1298 | if (signal_pending(current)) { |
1299 | spin_unlock(¤t->sighand->siglock); | |
1300 | write_unlock_irq(&tasklist_lock); | |
1301 | retval = -ERESTARTNOINTR; | |
425fb2b4 | 1302 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1303 | } |
1304 | ||
1da177e4 | 1305 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1306 | p->group_leader = current->group_leader; |
47e65328 | 1307 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1308 | |
1da177e4 LT |
1309 | if (!cputime_eq(current->signal->it_virt_expires, |
1310 | cputime_zero) || | |
1311 | !cputime_eq(current->signal->it_prof_expires, | |
1312 | cputime_zero) || | |
1313 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1314 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1315 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1316 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1317 | /* | |
1318 | * Have child wake up on its first tick to check | |
1319 | * for process CPU timers. | |
1320 | */ | |
1321 | p->it_prof_expires = jiffies_to_cputime(1); | |
1322 | } | |
1da177e4 LT |
1323 | } |
1324 | ||
73b9ebfe ON |
1325 | if (likely(p->pid)) { |
1326 | add_parent(p); | |
1327 | if (unlikely(p->ptrace & PT_PTRACED)) | |
1328 | __ptrace_link(p, current->parent); | |
1329 | ||
1330 | if (thread_group_leader(p)) { | |
5cd17569 | 1331 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1332 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1333 | |
fea9d175 | 1334 | p->signal->leader_pid = pid; |
5cd17569 EB |
1335 | p->signal->tty = current->signal->tty; |
1336 | set_task_pgrp(p, task_pgrp_nr(current)); | |
1337 | set_task_session(p, task_session_nr(current)); | |
1338 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); | |
1339 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
5e85d4ab | 1340 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1341 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1342 | } |
85868995 | 1343 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1344 | nr_threads++; |
1da177e4 LT |
1345 | } |
1346 | ||
1da177e4 | 1347 | total_forks++; |
3f17da69 | 1348 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1349 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1350 | proc_fork_connector(p); |
817929ec | 1351 | cgroup_post_fork(p); |
1da177e4 LT |
1352 | return p; |
1353 | ||
425fb2b4 PE |
1354 | bad_fork_free_pid: |
1355 | if (pid != &init_struct_pid) | |
1356 | free_pid(pid); | |
fd0928df JA |
1357 | bad_fork_cleanup_io: |
1358 | put_io_context(p->io_context); | |
ab516013 | 1359 | bad_fork_cleanup_namespaces: |
444f378b | 1360 | exit_task_namespaces(p); |
1da177e4 LT |
1361 | bad_fork_cleanup_keys: |
1362 | exit_keys(p); | |
1363 | bad_fork_cleanup_mm: | |
1364 | if (p->mm) | |
1365 | mmput(p->mm); | |
1366 | bad_fork_cleanup_signal: | |
6b3934ef | 1367 | cleanup_signal(p); |
1da177e4 | 1368 | bad_fork_cleanup_sighand: |
a7e5328a | 1369 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1370 | bad_fork_cleanup_fs: |
1371 | exit_fs(p); /* blocking */ | |
1372 | bad_fork_cleanup_files: | |
1373 | exit_files(p); /* blocking */ | |
1374 | bad_fork_cleanup_semundo: | |
1375 | exit_sem(p); | |
1376 | bad_fork_cleanup_audit: | |
1377 | audit_free(p); | |
1378 | bad_fork_cleanup_security: | |
1379 | security_task_free(p); | |
1380 | bad_fork_cleanup_policy: | |
1381 | #ifdef CONFIG_NUMA | |
f0be3d32 | 1382 | mpol_put(p->mempolicy); |
b4f48b63 | 1383 | bad_fork_cleanup_cgroup: |
1da177e4 | 1384 | #endif |
b4f48b63 | 1385 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1386 | delayacct_tsk_free(p); |
1da177e4 LT |
1387 | if (p->binfmt) |
1388 | module_put(p->binfmt->module); | |
1389 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1390 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1391 | bad_fork_cleanup_count: |
1392 | put_group_info(p->group_info); | |
1393 | atomic_dec(&p->user->processes); | |
1394 | free_uid(p->user); | |
1395 | bad_fork_free: | |
1396 | free_task(p); | |
fe7d37d1 ON |
1397 | fork_out: |
1398 | return ERR_PTR(retval); | |
1da177e4 LT |
1399 | } |
1400 | ||
6b2fb3c6 | 1401 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1402 | { |
1403 | memset(regs, 0, sizeof(struct pt_regs)); | |
1404 | return regs; | |
1405 | } | |
1406 | ||
9abcf40b | 1407 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1408 | { |
36c8b586 | 1409 | struct task_struct *task; |
1da177e4 LT |
1410 | struct pt_regs regs; |
1411 | ||
30e49c26 | 1412 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
85868995 | 1413 | &init_struct_pid); |
753ca4f3 AM |
1414 | if (!IS_ERR(task)) |
1415 | init_idle(task, cpu); | |
73b9ebfe | 1416 | |
1da177e4 LT |
1417 | return task; |
1418 | } | |
1419 | ||
a39bc516 | 1420 | static int fork_traceflag(unsigned clone_flags) |
1da177e4 LT |
1421 | { |
1422 | if (clone_flags & CLONE_UNTRACED) | |
1423 | return 0; | |
1424 | else if (clone_flags & CLONE_VFORK) { | |
1425 | if (current->ptrace & PT_TRACE_VFORK) | |
1426 | return PTRACE_EVENT_VFORK; | |
1427 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { | |
1428 | if (current->ptrace & PT_TRACE_CLONE) | |
1429 | return PTRACE_EVENT_CLONE; | |
1430 | } else if (current->ptrace & PT_TRACE_FORK) | |
1431 | return PTRACE_EVENT_FORK; | |
1432 | ||
1433 | return 0; | |
1434 | } | |
1435 | ||
1436 | /* | |
1437 | * Ok, this is the main fork-routine. | |
1438 | * | |
1439 | * It copies the process, and if successful kick-starts | |
1440 | * it and waits for it to finish using the VM if required. | |
1441 | */ | |
1442 | long do_fork(unsigned long clone_flags, | |
1443 | unsigned long stack_start, | |
1444 | struct pt_regs *regs, | |
1445 | unsigned long stack_size, | |
1446 | int __user *parent_tidptr, | |
1447 | int __user *child_tidptr) | |
1448 | { | |
1449 | struct task_struct *p; | |
1450 | int trace = 0; | |
92476d7f | 1451 | long nr; |
1da177e4 | 1452 | |
bdff746a AM |
1453 | /* |
1454 | * We hope to recycle these flags after 2.6.26 | |
1455 | */ | |
1456 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1457 | static int __read_mostly count = 100; | |
1458 | ||
1459 | if (count > 0 && printk_ratelimit()) { | |
1460 | char comm[TASK_COMM_LEN]; | |
1461 | ||
1462 | count--; | |
1463 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1464 | "clone flags 0x%lx\n", | |
1465 | get_task_comm(comm, current), | |
1466 | clone_flags & CLONE_STOPPED); | |
1467 | } | |
1468 | } | |
1469 | ||
1da177e4 LT |
1470 | if (unlikely(current->ptrace)) { |
1471 | trace = fork_traceflag (clone_flags); | |
1472 | if (trace) | |
1473 | clone_flags |= CLONE_PTRACE; | |
1474 | } | |
1475 | ||
a6f5e063 | 1476 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
30e49c26 | 1477 | child_tidptr, NULL); |
1da177e4 LT |
1478 | /* |
1479 | * Do this prior waking up the new thread - the thread pointer | |
1480 | * might get invalid after that point, if the thread exits quickly. | |
1481 | */ | |
1482 | if (!IS_ERR(p)) { | |
1483 | struct completion vfork; | |
1484 | ||
6c5f3e7b | 1485 | nr = task_pid_vnr(p); |
30e49c26 PE |
1486 | |
1487 | if (clone_flags & CLONE_PARENT_SETTID) | |
1488 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1489 | |
1da177e4 LT |
1490 | if (clone_flags & CLONE_VFORK) { |
1491 | p->vfork_done = &vfork; | |
1492 | init_completion(&vfork); | |
1493 | } | |
1494 | ||
1495 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { | |
1496 | /* | |
1497 | * We'll start up with an immediate SIGSTOP. | |
1498 | */ | |
1499 | sigaddset(&p->pending.signal, SIGSTOP); | |
1500 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
1501 | } | |
1502 | ||
1503 | if (!(clone_flags & CLONE_STOPPED)) | |
1504 | wake_up_new_task(p, clone_flags); | |
1505 | else | |
d9ae90ac | 1506 | __set_task_state(p, TASK_STOPPED); |
1da177e4 LT |
1507 | |
1508 | if (unlikely (trace)) { | |
92476d7f | 1509 | current->ptrace_message = nr; |
1da177e4 LT |
1510 | ptrace_notify ((trace << 8) | SIGTRAP); |
1511 | } | |
1512 | ||
1513 | if (clone_flags & CLONE_VFORK) { | |
ba96a0c8 | 1514 | freezer_do_not_count(); |
1da177e4 | 1515 | wait_for_completion(&vfork); |
ba96a0c8 | 1516 | freezer_count(); |
9f59ce5d CE |
1517 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) { |
1518 | current->ptrace_message = nr; | |
1da177e4 | 1519 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); |
9f59ce5d | 1520 | } |
1da177e4 LT |
1521 | } |
1522 | } else { | |
92476d7f | 1523 | nr = PTR_ERR(p); |
1da177e4 | 1524 | } |
92476d7f | 1525 | return nr; |
1da177e4 LT |
1526 | } |
1527 | ||
5fd63b30 RT |
1528 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1529 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1530 | #endif | |
1531 | ||
4ba9b9d0 | 1532 | static void sighand_ctor(struct kmem_cache *cachep, void *data) |
aa1757f9 ON |
1533 | { |
1534 | struct sighand_struct *sighand = data; | |
1535 | ||
a35afb83 | 1536 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1537 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1538 | } |
1539 | ||
1da177e4 LT |
1540 | void __init proc_caches_init(void) |
1541 | { | |
1542 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1543 | sizeof(struct sighand_struct), 0, | |
aa1757f9 | 1544 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
20c2df83 | 1545 | sighand_ctor); |
1da177e4 LT |
1546 | signal_cachep = kmem_cache_create("signal_cache", |
1547 | sizeof(struct signal_struct), 0, | |
20c2df83 PM |
1548 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1549 | files_cachep = kmem_cache_create("files_cache", | |
1da177e4 | 1550 | sizeof(struct files_struct), 0, |
20c2df83 PM |
1551 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1552 | fs_cachep = kmem_cache_create("fs_cache", | |
1da177e4 | 1553 | sizeof(struct fs_struct), 0, |
20c2df83 | 1554 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1555 | vm_area_cachep = kmem_cache_create("vm_area_struct", |
1556 | sizeof(struct vm_area_struct), 0, | |
20c2df83 | 1557 | SLAB_PANIC, NULL); |
1da177e4 | 1558 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1559 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
20c2df83 | 1560 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 1561 | } |
cf2e340f | 1562 | |
cf2e340f JD |
1563 | /* |
1564 | * Check constraints on flags passed to the unshare system call and | |
1565 | * force unsharing of additional process context as appropriate. | |
1566 | */ | |
a39bc516 | 1567 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1568 | { |
1569 | /* | |
1570 | * If unsharing a thread from a thread group, must also | |
1571 | * unshare vm. | |
1572 | */ | |
1573 | if (*flags_ptr & CLONE_THREAD) | |
1574 | *flags_ptr |= CLONE_VM; | |
1575 | ||
1576 | /* | |
1577 | * If unsharing vm, must also unshare signal handlers. | |
1578 | */ | |
1579 | if (*flags_ptr & CLONE_VM) | |
1580 | *flags_ptr |= CLONE_SIGHAND; | |
1581 | ||
1582 | /* | |
1583 | * If unsharing signal handlers and the task was created | |
1584 | * using CLONE_THREAD, then must unshare the thread | |
1585 | */ | |
1586 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1587 | (atomic_read(¤t->signal->count) > 1)) | |
1588 | *flags_ptr |= CLONE_THREAD; | |
1589 | ||
1590 | /* | |
1591 | * If unsharing namespace, must also unshare filesystem information. | |
1592 | */ | |
1593 | if (*flags_ptr & CLONE_NEWNS) | |
1594 | *flags_ptr |= CLONE_FS; | |
1595 | } | |
1596 | ||
1597 | /* | |
1598 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1599 | */ | |
1600 | static int unshare_thread(unsigned long unshare_flags) | |
1601 | { | |
1602 | if (unshare_flags & CLONE_THREAD) | |
1603 | return -EINVAL; | |
1604 | ||
1605 | return 0; | |
1606 | } | |
1607 | ||
1608 | /* | |
99d1419d | 1609 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1610 | */ |
1611 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1612 | { | |
1613 | struct fs_struct *fs = current->fs; | |
1614 | ||
1615 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1616 | (fs && atomic_read(&fs->count) > 1)) { |
1617 | *new_fsp = __copy_fs_struct(current->fs); | |
1618 | if (!*new_fsp) | |
1619 | return -ENOMEM; | |
1620 | } | |
cf2e340f JD |
1621 | |
1622 | return 0; | |
1623 | } | |
1624 | ||
cf2e340f | 1625 | /* |
dae3c5a0 | 1626 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1627 | */ |
1628 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1629 | { | |
1630 | struct sighand_struct *sigh = current->sighand; | |
1631 | ||
dae3c5a0 | 1632 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1633 | return -EINVAL; |
1634 | else | |
1635 | return 0; | |
1636 | } | |
1637 | ||
1638 | /* | |
a0a7ec30 | 1639 | * Unshare vm if it is being shared |
cf2e340f JD |
1640 | */ |
1641 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1642 | { | |
1643 | struct mm_struct *mm = current->mm; | |
1644 | ||
1645 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1646 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1647 | return -EINVAL; |
a0a7ec30 | 1648 | } |
cf2e340f JD |
1649 | |
1650 | return 0; | |
cf2e340f JD |
1651 | } |
1652 | ||
1653 | /* | |
a016f338 | 1654 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1655 | */ |
1656 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1657 | { | |
1658 | struct files_struct *fd = current->files; | |
a016f338 | 1659 | int error = 0; |
cf2e340f JD |
1660 | |
1661 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1662 | (fd && atomic_read(&fd->count) > 1)) { |
1663 | *new_fdp = dup_fd(fd, &error); | |
1664 | if (!*new_fdp) | |
1665 | return error; | |
1666 | } | |
cf2e340f JD |
1667 | |
1668 | return 0; | |
1669 | } | |
1670 | ||
cf2e340f JD |
1671 | /* |
1672 | * unshare allows a process to 'unshare' part of the process | |
1673 | * context which was originally shared using clone. copy_* | |
1674 | * functions used by do_fork() cannot be used here directly | |
1675 | * because they modify an inactive task_struct that is being | |
1676 | * constructed. Here we are modifying the current, active, | |
1677 | * task_struct. | |
1678 | */ | |
1679 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1680 | { | |
1681 | int err = 0; | |
1682 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1683 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1684 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1685 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1686 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1687 | int do_sysvsem = 0; |
cf2e340f JD |
1688 | |
1689 | check_unshare_flags(&unshare_flags); | |
1690 | ||
06f9d4f9 EB |
1691 | /* Return -EINVAL for all unsupported flags */ |
1692 | err = -EINVAL; | |
1693 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1694 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
9dd776b6 EB |
1695 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER| |
1696 | CLONE_NEWNET)) | |
06f9d4f9 EB |
1697 | goto bad_unshare_out; |
1698 | ||
9edff4ab MS |
1699 | if (unshare_flags & CLONE_SYSVSEM) |
1700 | do_sysvsem = 1; | |
cf2e340f JD |
1701 | if ((err = unshare_thread(unshare_flags))) |
1702 | goto bad_unshare_out; | |
1703 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1704 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1705 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1706 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1707 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1708 | goto bad_unshare_cleanup_sigh; | |
1709 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1710 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1711 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1712 | new_fs))) | |
9edff4ab | 1713 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1714 | |
9edff4ab MS |
1715 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1716 | if (do_sysvsem) { | |
1717 | /* | |
1718 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1719 | */ | |
1720 | exit_sem(current); | |
1721 | } | |
ab516013 | 1722 | |
c0b2fc31 | 1723 | if (new_nsproxy) { |
cf7b708c PE |
1724 | switch_task_namespaces(current, new_nsproxy); |
1725 | new_nsproxy = NULL; | |
c0b2fc31 | 1726 | } |
cf2e340f | 1727 | |
cf7b708c PE |
1728 | task_lock(current); |
1729 | ||
cf2e340f JD |
1730 | if (new_fs) { |
1731 | fs = current->fs; | |
1732 | current->fs = new_fs; | |
1733 | new_fs = fs; | |
1734 | } | |
1735 | ||
cf2e340f JD |
1736 | if (new_mm) { |
1737 | mm = current->mm; | |
1738 | active_mm = current->active_mm; | |
1739 | current->mm = new_mm; | |
1740 | current->active_mm = new_mm; | |
1741 | activate_mm(active_mm, new_mm); | |
1742 | new_mm = mm; | |
1743 | } | |
1744 | ||
1745 | if (new_fd) { | |
1746 | fd = current->files; | |
1747 | current->files = new_fd; | |
1748 | new_fd = fd; | |
1749 | } | |
1750 | ||
1751 | task_unlock(current); | |
1752 | } | |
1753 | ||
c0b2fc31 | 1754 | if (new_nsproxy) |
444f378b | 1755 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1756 | |
cf2e340f JD |
1757 | bad_unshare_cleanup_fd: |
1758 | if (new_fd) | |
1759 | put_files_struct(new_fd); | |
1760 | ||
1761 | bad_unshare_cleanup_vm: | |
1762 | if (new_mm) | |
1763 | mmput(new_mm); | |
1764 | ||
1765 | bad_unshare_cleanup_sigh: | |
1766 | if (new_sigh) | |
1767 | if (atomic_dec_and_test(&new_sigh->count)) | |
1768 | kmem_cache_free(sighand_cachep, new_sigh); | |
1769 | ||
cf2e340f JD |
1770 | bad_unshare_cleanup_fs: |
1771 | if (new_fs) | |
1772 | put_fs_struct(new_fs); | |
1773 | ||
1774 | bad_unshare_cleanup_thread: | |
1775 | bad_unshare_out: | |
1776 | return err; | |
1777 | } | |
3b125388 AV |
1778 | |
1779 | /* | |
1780 | * Helper to unshare the files of the current task. | |
1781 | * We don't want to expose copy_files internals to | |
1782 | * the exec layer of the kernel. | |
1783 | */ | |
1784 | ||
1785 | int unshare_files(struct files_struct **displaced) | |
1786 | { | |
1787 | struct task_struct *task = current; | |
50704516 | 1788 | struct files_struct *copy = NULL; |
3b125388 AV |
1789 | int error; |
1790 | ||
1791 | error = unshare_fd(CLONE_FILES, ©); | |
1792 | if (error || !copy) { | |
1793 | *displaced = NULL; | |
1794 | return error; | |
1795 | } | |
1796 | *displaced = task->files; | |
1797 | task_lock(task); | |
1798 | task->files = copy; | |
1799 | task_unlock(task); | |
1800 | return 0; | |
1801 | } |