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> | |
9f3acc31 | 25 | #include <linux/fdtable.h> |
da9cbc87 | 26 | #include <linux/iocontext.h> |
1da177e4 LT |
27 | #include <linux/key.h> |
28 | #include <linux/binfmts.h> | |
29 | #include <linux/mman.h> | |
cddb8a5c | 30 | #include <linux/mmu_notifier.h> |
1da177e4 | 31 | #include <linux/fs.h> |
ab516013 | 32 | #include <linux/nsproxy.h> |
c59ede7b | 33 | #include <linux/capability.h> |
1da177e4 | 34 | #include <linux/cpu.h> |
b4f48b63 | 35 | #include <linux/cgroup.h> |
1da177e4 | 36 | #include <linux/security.h> |
a1e78772 | 37 | #include <linux/hugetlb.h> |
1da177e4 LT |
38 | #include <linux/swap.h> |
39 | #include <linux/syscalls.h> | |
40 | #include <linux/jiffies.h> | |
09a05394 | 41 | #include <linux/tracehook.h> |
1da177e4 | 42 | #include <linux/futex.h> |
7c3ab738 | 43 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 44 | #include <linux/rcupdate.h> |
1da177e4 LT |
45 | #include <linux/ptrace.h> |
46 | #include <linux/mount.h> | |
47 | #include <linux/audit.h> | |
78fb7466 | 48 | #include <linux/memcontrol.h> |
1da177e4 LT |
49 | #include <linux/profile.h> |
50 | #include <linux/rmap.h> | |
51 | #include <linux/acct.h> | |
8f0ab514 | 52 | #include <linux/tsacct_kern.h> |
9f46080c | 53 | #include <linux/cn_proc.h> |
ba96a0c8 | 54 | #include <linux/freezer.h> |
ca74e92b | 55 | #include <linux/delayacct.h> |
ad4ecbcb | 56 | #include <linux/taskstats_kern.h> |
0a425405 | 57 | #include <linux/random.h> |
522ed776 | 58 | #include <linux/tty.h> |
6f4e6433 | 59 | #include <linux/proc_fs.h> |
fd0928df | 60 | #include <linux/blkdev.h> |
1da177e4 LT |
61 | |
62 | #include <asm/pgtable.h> | |
63 | #include <asm/pgalloc.h> | |
64 | #include <asm/uaccess.h> | |
65 | #include <asm/mmu_context.h> | |
66 | #include <asm/cacheflush.h> | |
67 | #include <asm/tlbflush.h> | |
68 | ||
69 | /* | |
70 | * Protected counters by write_lock_irq(&tasklist_lock) | |
71 | */ | |
72 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
73 | int nr_threads; /* The idle threads do not count.. */ | |
74 | ||
75 | int max_threads; /* tunable limit on nr_threads */ | |
76 | ||
77 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
78 | ||
c59923a1 | 79 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
80 | |
81 | int nr_processes(void) | |
82 | { | |
83 | int cpu; | |
84 | int total = 0; | |
85 | ||
86 | for_each_online_cpu(cpu) | |
87 | total += per_cpu(process_counts, cpu); | |
88 | ||
89 | return total; | |
90 | } | |
91 | ||
92 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
93 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
94 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 95 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
96 | #endif |
97 | ||
b69c49b7 FT |
98 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
99 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) | |
100 | { | |
101 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
102 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; | |
103 | #else | |
104 | gfp_t mask = GFP_KERNEL; | |
105 | #endif | |
106 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); | |
107 | } | |
108 | ||
109 | static inline void free_thread_info(struct thread_info *ti) | |
110 | { | |
111 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); | |
112 | } | |
113 | #endif | |
114 | ||
1da177e4 | 115 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 116 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
117 | |
118 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 119 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
120 | |
121 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 122 | struct kmem_cache *files_cachep; |
1da177e4 LT |
123 | |
124 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 125 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
126 | |
127 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 128 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
129 | |
130 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 131 | static struct kmem_cache *mm_cachep; |
1da177e4 LT |
132 | |
133 | void free_task(struct task_struct *tsk) | |
134 | { | |
3e26c149 | 135 | prop_local_destroy_single(&tsk->dirties); |
f7e4217b | 136 | free_thread_info(tsk->stack); |
23f78d4a | 137 | rt_mutex_debug_task_free(tsk); |
1da177e4 LT |
138 | free_task_struct(tsk); |
139 | } | |
140 | EXPORT_SYMBOL(free_task); | |
141 | ||
158d9ebd | 142 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 143 | { |
270f722d | 144 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
145 | WARN_ON(atomic_read(&tsk->usage)); |
146 | WARN_ON(tsk == current); | |
147 | ||
1da177e4 LT |
148 | security_task_free(tsk); |
149 | free_uid(tsk->user); | |
150 | put_group_info(tsk->group_info); | |
35df17c5 | 151 | delayacct_tsk_free(tsk); |
1da177e4 LT |
152 | |
153 | if (!profile_handoff_task(tsk)) | |
154 | free_task(tsk); | |
155 | } | |
156 | ||
2adee9b3 SS |
157 | /* |
158 | * macro override instead of weak attribute alias, to workaround | |
159 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
160 | */ | |
161 | #ifndef arch_task_cache_init | |
162 | #define arch_task_cache_init() | |
163 | #endif | |
61c4628b | 164 | |
1da177e4 LT |
165 | void __init fork_init(unsigned long mempages) |
166 | { | |
167 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
168 | #ifndef ARCH_MIN_TASKALIGN | |
169 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
170 | #endif | |
171 | /* create a slab on which task_structs can be allocated */ | |
172 | task_struct_cachep = | |
173 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
20c2df83 | 174 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL); |
1da177e4 LT |
175 | #endif |
176 | ||
61c4628b SS |
177 | /* do the arch specific task caches init */ |
178 | arch_task_cache_init(); | |
179 | ||
1da177e4 LT |
180 | /* |
181 | * The default maximum number of threads is set to a safe | |
182 | * value: the thread structures can take up at most half | |
183 | * of memory. | |
184 | */ | |
185 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
186 | ||
187 | /* | |
188 | * we need to allow at least 20 threads to boot a system | |
189 | */ | |
190 | if(max_threads < 20) | |
191 | max_threads = 20; | |
192 | ||
193 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
194 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
195 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
196 | init_task.signal->rlim[RLIMIT_NPROC]; | |
197 | } | |
198 | ||
61c4628b SS |
199 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
200 | struct task_struct *src) | |
201 | { | |
202 | *dst = *src; | |
203 | return 0; | |
204 | } | |
205 | ||
1da177e4 LT |
206 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
207 | { | |
208 | struct task_struct *tsk; | |
209 | struct thread_info *ti; | |
3e26c149 | 210 | int err; |
1da177e4 LT |
211 | |
212 | prepare_to_copy(orig); | |
213 | ||
214 | tsk = alloc_task_struct(); | |
215 | if (!tsk) | |
216 | return NULL; | |
217 | ||
218 | ti = alloc_thread_info(tsk); | |
219 | if (!ti) { | |
220 | free_task_struct(tsk); | |
221 | return NULL; | |
222 | } | |
223 | ||
61c4628b SS |
224 | err = arch_dup_task_struct(tsk, orig); |
225 | if (err) | |
226 | goto out; | |
227 | ||
f7e4217b | 228 | tsk->stack = ti; |
3e26c149 PZ |
229 | |
230 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
231 | if (err) |
232 | goto out; | |
3e26c149 | 233 | |
10ebffde | 234 | setup_thread_stack(tsk, orig); |
1da177e4 | 235 | |
0a425405 AV |
236 | #ifdef CONFIG_CC_STACKPROTECTOR |
237 | tsk->stack_canary = get_random_int(); | |
238 | #endif | |
239 | ||
1da177e4 LT |
240 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
241 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 242 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 243 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 244 | tsk->btrace_seq = 0; |
6c5c9341 | 245 | #endif |
a0aa7f68 | 246 | tsk->splice_pipe = NULL; |
1da177e4 | 247 | return tsk; |
61c4628b SS |
248 | |
249 | out: | |
250 | free_thread_info(ti); | |
251 | free_task_struct(tsk); | |
252 | return NULL; | |
1da177e4 LT |
253 | } |
254 | ||
255 | #ifdef CONFIG_MMU | |
a39bc516 | 256 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 257 | { |
fd3e42fc | 258 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
259 | struct rb_node **rb_link, *rb_parent; |
260 | int retval; | |
261 | unsigned long charge; | |
262 | struct mempolicy *pol; | |
263 | ||
264 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 265 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
266 | /* |
267 | * Not linked in yet - no deadlock potential: | |
268 | */ | |
269 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 270 | |
1da177e4 LT |
271 | mm->locked_vm = 0; |
272 | mm->mmap = NULL; | |
273 | mm->mmap_cache = NULL; | |
274 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 275 | mm->cached_hole_size = ~0UL; |
1da177e4 | 276 | mm->map_count = 0; |
1da177e4 LT |
277 | cpus_clear(mm->cpu_vm_mask); |
278 | mm->mm_rb = RB_ROOT; | |
279 | rb_link = &mm->mm_rb.rb_node; | |
280 | rb_parent = NULL; | |
281 | pprev = &mm->mmap; | |
282 | ||
fd3e42fc | 283 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
284 | struct file *file; |
285 | ||
286 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
287 | long pages = vma_pages(mpnt); |
288 | mm->total_vm -= pages; | |
ab50b8ed | 289 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 290 | -pages); |
1da177e4 LT |
291 | continue; |
292 | } | |
293 | charge = 0; | |
294 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
295 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
296 | if (security_vm_enough_memory(len)) | |
297 | goto fail_nomem; | |
298 | charge = len; | |
299 | } | |
e94b1766 | 300 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
301 | if (!tmp) |
302 | goto fail_nomem; | |
303 | *tmp = *mpnt; | |
846a16bf | 304 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
305 | retval = PTR_ERR(pol); |
306 | if (IS_ERR(pol)) | |
307 | goto fail_nomem_policy; | |
308 | vma_set_policy(tmp, pol); | |
309 | tmp->vm_flags &= ~VM_LOCKED; | |
310 | tmp->vm_mm = mm; | |
311 | tmp->vm_next = NULL; | |
312 | anon_vma_link(tmp); | |
313 | file = tmp->vm_file; | |
314 | if (file) { | |
f3a43f3f | 315 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
316 | get_file(file); |
317 | if (tmp->vm_flags & VM_DENYWRITE) | |
318 | atomic_dec(&inode->i_writecount); | |
23ff4440 | 319 | |
1da177e4 LT |
320 | /* insert tmp into the share list, just after mpnt */ |
321 | spin_lock(&file->f_mapping->i_mmap_lock); | |
322 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
323 | flush_dcache_mmap_lock(file->f_mapping); | |
324 | vma_prio_tree_add(tmp, mpnt); | |
325 | flush_dcache_mmap_unlock(file->f_mapping); | |
326 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
327 | } | |
328 | ||
a1e78772 MG |
329 | /* |
330 | * Clear hugetlb-related page reserves for children. This only | |
331 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
332 | * are not guaranteed to succeed, even if read-only | |
333 | */ | |
334 | if (is_vm_hugetlb_page(tmp)) | |
335 | reset_vma_resv_huge_pages(tmp); | |
336 | ||
1da177e4 | 337 | /* |
7ee78232 | 338 | * Link in the new vma and copy the page table entries. |
1da177e4 | 339 | */ |
1da177e4 LT |
340 | *pprev = tmp; |
341 | pprev = &tmp->vm_next; | |
342 | ||
343 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
344 | rb_link = &tmp->vm_rb.rb_right; | |
345 | rb_parent = &tmp->vm_rb; | |
346 | ||
347 | mm->map_count++; | |
0b0db14c | 348 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
349 | |
350 | if (tmp->vm_ops && tmp->vm_ops->open) | |
351 | tmp->vm_ops->open(tmp); | |
352 | ||
353 | if (retval) | |
354 | goto out; | |
355 | } | |
d6dd61c8 JF |
356 | /* a new mm has just been created */ |
357 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 358 | retval = 0; |
1da177e4 | 359 | out: |
7ee78232 | 360 | up_write(&mm->mmap_sem); |
fd3e42fc | 361 | flush_tlb_mm(oldmm); |
1da177e4 LT |
362 | up_write(&oldmm->mmap_sem); |
363 | return retval; | |
364 | fail_nomem_policy: | |
365 | kmem_cache_free(vm_area_cachep, tmp); | |
366 | fail_nomem: | |
367 | retval = -ENOMEM; | |
368 | vm_unacct_memory(charge); | |
369 | goto out; | |
370 | } | |
371 | ||
372 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
373 | { | |
374 | mm->pgd = pgd_alloc(mm); | |
375 | if (unlikely(!mm->pgd)) | |
376 | return -ENOMEM; | |
377 | return 0; | |
378 | } | |
379 | ||
380 | static inline void mm_free_pgd(struct mm_struct * mm) | |
381 | { | |
5e541973 | 382 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
383 | } |
384 | #else | |
385 | #define dup_mmap(mm, oldmm) (0) | |
386 | #define mm_alloc_pgd(mm) (0) | |
387 | #define mm_free_pgd(mm) | |
388 | #endif /* CONFIG_MMU */ | |
389 | ||
23ff4440 | 390 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 391 | |
e94b1766 | 392 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
393 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
394 | ||
395 | #include <linux/init_task.h> | |
396 | ||
78fb7466 | 397 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
398 | { |
399 | atomic_set(&mm->mm_users, 1); | |
400 | atomic_set(&mm->mm_count, 1); | |
401 | init_rwsem(&mm->mmap_sem); | |
402 | INIT_LIST_HEAD(&mm->mmlist); | |
3cb4a0bb KH |
403 | mm->flags = (current->mm) ? current->mm->flags |
404 | : MMF_DUMP_FILTER_DEFAULT; | |
999d9fc1 | 405 | mm->core_state = NULL; |
1da177e4 | 406 | mm->nr_ptes = 0; |
4294621f | 407 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 408 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
409 | spin_lock_init(&mm->page_table_lock); |
410 | rwlock_init(&mm->ioctx_list_lock); | |
411 | mm->ioctx_list = NULL; | |
1da177e4 | 412 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 413 | mm->cached_hole_size = ~0UL; |
cf475ad2 | 414 | mm_init_owner(mm, p); |
1da177e4 LT |
415 | |
416 | if (likely(!mm_alloc_pgd(mm))) { | |
417 | mm->def_flags = 0; | |
cddb8a5c | 418 | mmu_notifier_mm_init(mm); |
1da177e4 LT |
419 | return mm; |
420 | } | |
78fb7466 | 421 | |
1da177e4 LT |
422 | free_mm(mm); |
423 | return NULL; | |
424 | } | |
425 | ||
426 | /* | |
427 | * Allocate and initialize an mm_struct. | |
428 | */ | |
429 | struct mm_struct * mm_alloc(void) | |
430 | { | |
431 | struct mm_struct * mm; | |
432 | ||
433 | mm = allocate_mm(); | |
434 | if (mm) { | |
435 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 436 | mm = mm_init(mm, current); |
1da177e4 LT |
437 | } |
438 | return mm; | |
439 | } | |
440 | ||
441 | /* | |
442 | * Called when the last reference to the mm | |
443 | * is dropped: either by a lazy thread or by | |
444 | * mmput. Free the page directory and the mm. | |
445 | */ | |
7ad5b3a5 | 446 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
447 | { |
448 | BUG_ON(mm == &init_mm); | |
449 | mm_free_pgd(mm); | |
450 | destroy_context(mm); | |
cddb8a5c | 451 | mmu_notifier_mm_destroy(mm); |
1da177e4 LT |
452 | free_mm(mm); |
453 | } | |
6d4e4c4f | 454 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
455 | |
456 | /* | |
457 | * Decrement the use count and release all resources for an mm. | |
458 | */ | |
459 | void mmput(struct mm_struct *mm) | |
460 | { | |
0ae26f1b AM |
461 | might_sleep(); |
462 | ||
1da177e4 LT |
463 | if (atomic_dec_and_test(&mm->mm_users)) { |
464 | exit_aio(mm); | |
465 | exit_mmap(mm); | |
925d1c40 | 466 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
467 | if (!list_empty(&mm->mmlist)) { |
468 | spin_lock(&mmlist_lock); | |
469 | list_del(&mm->mmlist); | |
470 | spin_unlock(&mmlist_lock); | |
471 | } | |
472 | put_swap_token(mm); | |
473 | mmdrop(mm); | |
474 | } | |
475 | } | |
476 | EXPORT_SYMBOL_GPL(mmput); | |
477 | ||
478 | /** | |
479 | * get_task_mm - acquire a reference to the task's mm | |
480 | * | |
246bb0b1 | 481 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
482 | * this kernel workthread has transiently adopted a user mm with use_mm, |
483 | * to do its AIO) is not set and if so returns a reference to it, after | |
484 | * bumping up the use count. User must release the mm via mmput() | |
485 | * after use. Typically used by /proc and ptrace. | |
486 | */ | |
487 | struct mm_struct *get_task_mm(struct task_struct *task) | |
488 | { | |
489 | struct mm_struct *mm; | |
490 | ||
491 | task_lock(task); | |
492 | mm = task->mm; | |
493 | if (mm) { | |
246bb0b1 | 494 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
495 | mm = NULL; |
496 | else | |
497 | atomic_inc(&mm->mm_users); | |
498 | } | |
499 | task_unlock(task); | |
500 | return mm; | |
501 | } | |
502 | EXPORT_SYMBOL_GPL(get_task_mm); | |
503 | ||
504 | /* Please note the differences between mmput and mm_release. | |
505 | * mmput is called whenever we stop holding onto a mm_struct, | |
506 | * error success whatever. | |
507 | * | |
508 | * mm_release is called after a mm_struct has been removed | |
509 | * from the current process. | |
510 | * | |
511 | * This difference is important for error handling, when we | |
512 | * only half set up a mm_struct for a new process and need to restore | |
513 | * the old one. Because we mmput the new mm_struct before | |
514 | * restoring the old one. . . | |
515 | * Eric Biederman 10 January 1998 | |
516 | */ | |
517 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
518 | { | |
519 | struct completion *vfork_done = tsk->vfork_done; | |
520 | ||
521 | /* Get rid of any cached register state */ | |
522 | deactivate_mm(tsk, mm); | |
523 | ||
524 | /* notify parent sleeping on vfork() */ | |
525 | if (vfork_done) { | |
526 | tsk->vfork_done = NULL; | |
527 | complete(vfork_done); | |
528 | } | |
fec1d011 RM |
529 | |
530 | /* | |
531 | * If we're exiting normally, clear a user-space tid field if | |
532 | * requested. We leave this alone when dying by signal, to leave | |
533 | * the value intact in a core dump, and to save the unnecessary | |
534 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
535 | */ | |
536 | if (tsk->clear_child_tid | |
537 | && !(tsk->flags & PF_SIGNALED) | |
538 | && atomic_read(&mm->mm_users) > 1) { | |
1da177e4 LT |
539 | u32 __user * tidptr = tsk->clear_child_tid; |
540 | tsk->clear_child_tid = NULL; | |
541 | ||
542 | /* | |
543 | * We don't check the error code - if userspace has | |
544 | * not set up a proper pointer then tough luck. | |
545 | */ | |
546 | put_user(0, tidptr); | |
547 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
548 | } | |
549 | } | |
550 | ||
a0a7ec30 JD |
551 | /* |
552 | * Allocate a new mm structure and copy contents from the | |
553 | * mm structure of the passed in task structure. | |
554 | */ | |
402b0862 | 555 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
556 | { |
557 | struct mm_struct *mm, *oldmm = current->mm; | |
558 | int err; | |
559 | ||
560 | if (!oldmm) | |
561 | return NULL; | |
562 | ||
563 | mm = allocate_mm(); | |
564 | if (!mm) | |
565 | goto fail_nomem; | |
566 | ||
567 | memcpy(mm, oldmm, sizeof(*mm)); | |
568 | ||
7602bdf2 AC |
569 | /* Initializing for Swap token stuff */ |
570 | mm->token_priority = 0; | |
571 | mm->last_interval = 0; | |
572 | ||
78fb7466 | 573 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
574 | goto fail_nomem; |
575 | ||
576 | if (init_new_context(tsk, mm)) | |
577 | goto fail_nocontext; | |
578 | ||
925d1c40 MH |
579 | dup_mm_exe_file(oldmm, mm); |
580 | ||
a0a7ec30 JD |
581 | err = dup_mmap(mm, oldmm); |
582 | if (err) | |
583 | goto free_pt; | |
584 | ||
585 | mm->hiwater_rss = get_mm_rss(mm); | |
586 | mm->hiwater_vm = mm->total_vm; | |
587 | ||
588 | return mm; | |
589 | ||
590 | free_pt: | |
591 | mmput(mm); | |
592 | ||
593 | fail_nomem: | |
594 | return NULL; | |
595 | ||
596 | fail_nocontext: | |
597 | /* | |
598 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
599 | * because it calls destroy_context() | |
600 | */ | |
601 | mm_free_pgd(mm); | |
602 | free_mm(mm); | |
603 | return NULL; | |
604 | } | |
605 | ||
1da177e4 LT |
606 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
607 | { | |
608 | struct mm_struct * mm, *oldmm; | |
609 | int retval; | |
610 | ||
611 | tsk->min_flt = tsk->maj_flt = 0; | |
612 | tsk->nvcsw = tsk->nivcsw = 0; | |
613 | ||
614 | tsk->mm = NULL; | |
615 | tsk->active_mm = NULL; | |
616 | ||
617 | /* | |
618 | * Are we cloning a kernel thread? | |
619 | * | |
620 | * We need to steal a active VM for that.. | |
621 | */ | |
622 | oldmm = current->mm; | |
623 | if (!oldmm) | |
624 | return 0; | |
625 | ||
626 | if (clone_flags & CLONE_VM) { | |
627 | atomic_inc(&oldmm->mm_users); | |
628 | mm = oldmm; | |
1da177e4 LT |
629 | goto good_mm; |
630 | } | |
631 | ||
632 | retval = -ENOMEM; | |
a0a7ec30 | 633 | mm = dup_mm(tsk); |
1da177e4 LT |
634 | if (!mm) |
635 | goto fail_nomem; | |
636 | ||
1da177e4 | 637 | good_mm: |
7602bdf2 AC |
638 | /* Initializing for Swap token stuff */ |
639 | mm->token_priority = 0; | |
640 | mm->last_interval = 0; | |
641 | ||
1da177e4 LT |
642 | tsk->mm = mm; |
643 | tsk->active_mm = mm; | |
644 | return 0; | |
645 | ||
1da177e4 LT |
646 | fail_nomem: |
647 | return retval; | |
1da177e4 LT |
648 | } |
649 | ||
a39bc516 | 650 | static struct fs_struct *__copy_fs_struct(struct fs_struct *old) |
1da177e4 LT |
651 | { |
652 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
653 | /* We don't need to lock fs - think why ;-) */ | |
654 | if (fs) { | |
655 | atomic_set(&fs->count, 1); | |
656 | rwlock_init(&fs->lock); | |
657 | fs->umask = old->umask; | |
658 | read_lock(&old->lock); | |
6ac08c39 JB |
659 | fs->root = old->root; |
660 | path_get(&old->root); | |
661 | fs->pwd = old->pwd; | |
662 | path_get(&old->pwd); | |
1da177e4 LT |
663 | read_unlock(&old->lock); |
664 | } | |
665 | return fs; | |
666 | } | |
667 | ||
668 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
669 | { | |
670 | return __copy_fs_struct(old); | |
671 | } | |
672 | ||
673 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
674 | ||
a39bc516 | 675 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
676 | { |
677 | if (clone_flags & CLONE_FS) { | |
678 | atomic_inc(¤t->fs->count); | |
679 | return 0; | |
680 | } | |
681 | tsk->fs = __copy_fs_struct(current->fs); | |
682 | if (!tsk->fs) | |
683 | return -ENOMEM; | |
684 | return 0; | |
685 | } | |
686 | ||
a016f338 JD |
687 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
688 | { | |
689 | struct files_struct *oldf, *newf; | |
690 | int error = 0; | |
691 | ||
692 | /* | |
693 | * A background process may not have any files ... | |
694 | */ | |
695 | oldf = current->files; | |
696 | if (!oldf) | |
697 | goto out; | |
698 | ||
699 | if (clone_flags & CLONE_FILES) { | |
700 | atomic_inc(&oldf->count); | |
701 | goto out; | |
702 | } | |
703 | ||
a016f338 JD |
704 | newf = dup_fd(oldf, &error); |
705 | if (!newf) | |
706 | goto out; | |
707 | ||
708 | tsk->files = newf; | |
709 | error = 0; | |
710 | out: | |
711 | return error; | |
712 | } | |
713 | ||
fadad878 | 714 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
715 | { |
716 | #ifdef CONFIG_BLOCK | |
717 | struct io_context *ioc = current->io_context; | |
718 | ||
719 | if (!ioc) | |
720 | return 0; | |
fadad878 JA |
721 | /* |
722 | * Share io context with parent, if CLONE_IO is set | |
723 | */ | |
724 | if (clone_flags & CLONE_IO) { | |
725 | tsk->io_context = ioc_task_link(ioc); | |
726 | if (unlikely(!tsk->io_context)) | |
727 | return -ENOMEM; | |
728 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
729 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
730 | if (unlikely(!tsk->io_context)) | |
731 | return -ENOMEM; | |
732 | ||
fd0928df JA |
733 | tsk->io_context->ioprio = ioc->ioprio; |
734 | } | |
735 | #endif | |
736 | return 0; | |
737 | } | |
738 | ||
a39bc516 | 739 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
740 | { |
741 | struct sighand_struct *sig; | |
742 | ||
743 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
744 | atomic_inc(¤t->sighand->count); | |
745 | return 0; | |
746 | } | |
747 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 748 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
749 | if (!sig) |
750 | return -ENOMEM; | |
1da177e4 LT |
751 | atomic_set(&sig->count, 1); |
752 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
753 | return 0; | |
754 | } | |
755 | ||
a7e5328a | 756 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 757 | { |
c81addc9 ON |
758 | if (atomic_dec_and_test(&sighand->count)) |
759 | kmem_cache_free(sighand_cachep, sighand); | |
760 | } | |
761 | ||
a39bc516 | 762 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
763 | { |
764 | struct signal_struct *sig; | |
765 | int ret; | |
766 | ||
767 | if (clone_flags & CLONE_THREAD) { | |
768 | atomic_inc(¤t->signal->count); | |
769 | atomic_inc(¤t->signal->live); | |
770 | return 0; | |
771 | } | |
772 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
773 | tsk->signal = sig; | |
774 | if (!sig) | |
775 | return -ENOMEM; | |
776 | ||
777 | ret = copy_thread_group_keys(tsk); | |
778 | if (ret < 0) { | |
779 | kmem_cache_free(signal_cachep, sig); | |
780 | return ret; | |
781 | } | |
782 | ||
783 | atomic_set(&sig->count, 1); | |
784 | atomic_set(&sig->live, 1); | |
785 | init_waitqueue_head(&sig->wait_chldexit); | |
786 | sig->flags = 0; | |
787 | sig->group_exit_code = 0; | |
788 | sig->group_exit_task = NULL; | |
789 | sig->group_stop_count = 0; | |
db51aecc | 790 | sig->curr_target = tsk; |
1da177e4 LT |
791 | init_sigpending(&sig->shared_pending); |
792 | INIT_LIST_HEAD(&sig->posix_timers); | |
793 | ||
c9cb2e3d | 794 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
2ff678b8 | 795 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 796 | sig->real_timer.function = it_real_fn; |
1da177e4 LT |
797 | |
798 | sig->it_virt_expires = cputime_zero; | |
799 | sig->it_virt_incr = cputime_zero; | |
800 | sig->it_prof_expires = cputime_zero; | |
801 | sig->it_prof_incr = cputime_zero; | |
802 | ||
1da177e4 | 803 | sig->leader = 0; /* session leadership doesn't inherit */ |
ab521dc0 | 804 | sig->tty_old_pgrp = NULL; |
1da177e4 LT |
805 | |
806 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
9ac52315 LV |
807 | sig->gtime = cputime_zero; |
808 | sig->cgtime = cputime_zero; | |
1da177e4 LT |
809 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
810 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
6eaeeaba | 811 | sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; |
5995477a | 812 | task_io_accounting_init(&sig->ioac); |
172ba844 | 813 | sig->sum_sched_runtime = 0; |
1da177e4 LT |
814 | INIT_LIST_HEAD(&sig->cpu_timers[0]); |
815 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
816 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
ad4ecbcb | 817 | taskstats_tgid_init(sig); |
1da177e4 LT |
818 | |
819 | task_lock(current->group_leader); | |
820 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
821 | task_unlock(current->group_leader); | |
822 | ||
823 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
824 | /* | |
825 | * New sole thread in the process gets an expiry time | |
826 | * of the whole CPU time limit. | |
827 | */ | |
828 | tsk->it_prof_expires = | |
829 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
830 | } | |
0e464814 | 831 | acct_init_pacct(&sig->pacct); |
1da177e4 | 832 | |
522ed776 MT |
833 | tty_audit_fork(sig); |
834 | ||
1da177e4 LT |
835 | return 0; |
836 | } | |
837 | ||
6b3934ef ON |
838 | void __cleanup_signal(struct signal_struct *sig) |
839 | { | |
840 | exit_thread_group_keys(sig); | |
841 | kmem_cache_free(signal_cachep, sig); | |
842 | } | |
843 | ||
a39bc516 | 844 | static void cleanup_signal(struct task_struct *tsk) |
6b3934ef ON |
845 | { |
846 | struct signal_struct *sig = tsk->signal; | |
847 | ||
848 | atomic_dec(&sig->live); | |
849 | ||
850 | if (atomic_dec_and_test(&sig->count)) | |
851 | __cleanup_signal(sig); | |
852 | } | |
853 | ||
a39bc516 | 854 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
855 | { |
856 | unsigned long new_flags = p->flags; | |
857 | ||
83144186 | 858 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 | 859 | new_flags |= PF_FORKNOEXEC; |
09a05394 | 860 | new_flags |= PF_STARTING; |
1da177e4 | 861 | p->flags = new_flags; |
2e131895 | 862 | clear_freeze_flag(p); |
1da177e4 LT |
863 | } |
864 | ||
865 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
866 | { | |
867 | current->clear_child_tid = tidptr; | |
868 | ||
b488893a | 869 | return task_pid_vnr(current); |
1da177e4 LT |
870 | } |
871 | ||
a39bc516 | 872 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 873 | { |
23f78d4a | 874 | spin_lock_init(&p->pi_lock); |
e29e175b | 875 | #ifdef CONFIG_RT_MUTEXES |
23f78d4a IM |
876 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
877 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
878 | #endif |
879 | } | |
880 | ||
cf475ad2 BS |
881 | #ifdef CONFIG_MM_OWNER |
882 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
883 | { | |
884 | mm->owner = p; | |
885 | } | |
886 | #endif /* CONFIG_MM_OWNER */ | |
887 | ||
1da177e4 LT |
888 | /* |
889 | * This creates a new process as a copy of the old one, | |
890 | * but does not actually start it yet. | |
891 | * | |
892 | * It copies the registers, and all the appropriate | |
893 | * parts of the process environment (as per the clone | |
894 | * flags). The actual kick-off is left to the caller. | |
895 | */ | |
36c8b586 IM |
896 | static struct task_struct *copy_process(unsigned long clone_flags, |
897 | unsigned long stack_start, | |
898 | struct pt_regs *regs, | |
899 | unsigned long stack_size, | |
36c8b586 | 900 | int __user *child_tidptr, |
09a05394 RM |
901 | struct pid *pid, |
902 | int trace) | |
1da177e4 LT |
903 | { |
904 | int retval; | |
a24efe62 | 905 | struct task_struct *p; |
b4f48b63 | 906 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
907 | |
908 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
909 | return ERR_PTR(-EINVAL); | |
910 | ||
911 | /* | |
912 | * Thread groups must share signals as well, and detached threads | |
913 | * can only be started up within the thread group. | |
914 | */ | |
915 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
916 | return ERR_PTR(-EINVAL); | |
917 | ||
918 | /* | |
919 | * Shared signal handlers imply shared VM. By way of the above, | |
920 | * thread groups also imply shared VM. Blocking this case allows | |
921 | * for various simplifications in other code. | |
922 | */ | |
923 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
924 | return ERR_PTR(-EINVAL); | |
925 | ||
926 | retval = security_task_create(clone_flags); | |
927 | if (retval) | |
928 | goto fork_out; | |
929 | ||
930 | retval = -ENOMEM; | |
931 | p = dup_task_struct(current); | |
932 | if (!p) | |
933 | goto fork_out; | |
934 | ||
bea493a0 PZ |
935 | rt_mutex_init_task(p); |
936 | ||
d12c1a37 | 937 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
938 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
939 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
940 | #endif | |
1da177e4 LT |
941 | retval = -EAGAIN; |
942 | if (atomic_read(&p->user->processes) >= | |
943 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
944 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
acce292c | 945 | p->user != current->nsproxy->user_ns->root_user) |
1da177e4 LT |
946 | goto bad_fork_free; |
947 | } | |
948 | ||
949 | atomic_inc(&p->user->__count); | |
950 | atomic_inc(&p->user->processes); | |
951 | get_group_info(p->group_info); | |
952 | ||
953 | /* | |
954 | * If multiple threads are within copy_process(), then this check | |
955 | * triggers too late. This doesn't hurt, the check is only there | |
956 | * to stop root fork bombs. | |
957 | */ | |
958 | if (nr_threads >= max_threads) | |
959 | goto bad_fork_cleanup_count; | |
960 | ||
a1261f54 | 961 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
962 | goto bad_fork_cleanup_count; |
963 | ||
964 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
965 | goto bad_fork_cleanup_put_domain; | |
966 | ||
967 | p->did_exec = 0; | |
ca74e92b | 968 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 969 | copy_flags(clone_flags, p); |
1da177e4 LT |
970 | INIT_LIST_HEAD(&p->children); |
971 | INIT_LIST_HEAD(&p->sibling); | |
e260be67 PM |
972 | #ifdef CONFIG_PREEMPT_RCU |
973 | p->rcu_read_lock_nesting = 0; | |
974 | p->rcu_flipctr_idx = 0; | |
975 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1da177e4 LT |
976 | p->vfork_done = NULL; |
977 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
978 | |
979 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
980 | init_sigpending(&p->pending); | |
981 | ||
982 | p->utime = cputime_zero; | |
983 | p->stime = cputime_zero; | |
9ac52315 | 984 | p->gtime = cputime_zero; |
c66f08be MN |
985 | p->utimescaled = cputime_zero; |
986 | p->stimescaled = cputime_zero; | |
73a2bcb0 | 987 | p->prev_utime = cputime_zero; |
9301899b | 988 | p->prev_stime = cputime_zero; |
172ba844 | 989 | |
82a1fcb9 IM |
990 | #ifdef CONFIG_DETECT_SOFTLOCKUP |
991 | p->last_switch_count = 0; | |
992 | p->last_switch_timestamp = 0; | |
993 | #endif | |
994 | ||
5995477a | 995 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
996 | acct_clear_integrals(p); |
997 | ||
23ff4440 | 998 | p->it_virt_expires = cputime_zero; |
1da177e4 | 999 | p->it_prof_expires = cputime_zero; |
23ff4440 DW |
1000 | p->it_sched_expires = 0; |
1001 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1002 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1003 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1da177e4 LT |
1004 | |
1005 | p->lock_depth = -1; /* -1 = no lock */ | |
1006 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1007 | p->real_start_time = p->start_time; |
1008 | monotonic_to_bootbased(&p->real_start_time); | |
57c521ce | 1009 | #ifdef CONFIG_SECURITY |
1da177e4 | 1010 | p->security = NULL; |
57c521ce | 1011 | #endif |
3b7391de | 1012 | p->cap_bset = current->cap_bset; |
1da177e4 | 1013 | p->io_context = NULL; |
1da177e4 | 1014 | p->audit_context = NULL; |
b4f48b63 | 1015 | cgroup_fork(p); |
1da177e4 | 1016 | #ifdef CONFIG_NUMA |
846a16bf | 1017 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1018 | if (IS_ERR(p->mempolicy)) { |
1019 | retval = PTR_ERR(p->mempolicy); | |
1020 | p->mempolicy = NULL; | |
b4f48b63 | 1021 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1022 | } |
c61afb18 | 1023 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1024 | #endif |
de30a2b3 IM |
1025 | #ifdef CONFIG_TRACE_IRQFLAGS |
1026 | p->irq_events = 0; | |
b36e4758 RK |
1027 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1028 | p->hardirqs_enabled = 1; | |
1029 | #else | |
de30a2b3 | 1030 | p->hardirqs_enabled = 0; |
b36e4758 | 1031 | #endif |
de30a2b3 IM |
1032 | p->hardirq_enable_ip = 0; |
1033 | p->hardirq_enable_event = 0; | |
1034 | p->hardirq_disable_ip = _THIS_IP_; | |
1035 | p->hardirq_disable_event = 0; | |
1036 | p->softirqs_enabled = 1; | |
1037 | p->softirq_enable_ip = _THIS_IP_; | |
1038 | p->softirq_enable_event = 0; | |
1039 | p->softirq_disable_ip = 0; | |
1040 | p->softirq_disable_event = 0; | |
1041 | p->hardirq_context = 0; | |
1042 | p->softirq_context = 0; | |
1043 | #endif | |
fbb9ce95 IM |
1044 | #ifdef CONFIG_LOCKDEP |
1045 | p->lockdep_depth = 0; /* no locks held yet */ | |
1046 | p->curr_chain_key = 0; | |
1047 | p->lockdep_recursion = 0; | |
1048 | #endif | |
1da177e4 | 1049 | |
408894ee IM |
1050 | #ifdef CONFIG_DEBUG_MUTEXES |
1051 | p->blocked_on = NULL; /* not blocked yet */ | |
1052 | #endif | |
1053 | ||
3c90e6e9 SV |
1054 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1055 | sched_fork(p, clone_flags); | |
1056 | ||
1da177e4 LT |
1057 | if ((retval = security_task_alloc(p))) |
1058 | goto bad_fork_cleanup_policy; | |
1059 | if ((retval = audit_alloc(p))) | |
1060 | goto bad_fork_cleanup_security; | |
1061 | /* copy all the process information */ | |
1062 | if ((retval = copy_semundo(clone_flags, p))) | |
1063 | goto bad_fork_cleanup_audit; | |
1064 | if ((retval = copy_files(clone_flags, p))) | |
1065 | goto bad_fork_cleanup_semundo; | |
1066 | if ((retval = copy_fs(clone_flags, p))) | |
1067 | goto bad_fork_cleanup_files; | |
1068 | if ((retval = copy_sighand(clone_flags, p))) | |
1069 | goto bad_fork_cleanup_fs; | |
1070 | if ((retval = copy_signal(clone_flags, p))) | |
1071 | goto bad_fork_cleanup_sighand; | |
1072 | if ((retval = copy_mm(clone_flags, p))) | |
1073 | goto bad_fork_cleanup_signal; | |
1074 | if ((retval = copy_keys(clone_flags, p))) | |
1075 | goto bad_fork_cleanup_mm; | |
ab516013 | 1076 | if ((retval = copy_namespaces(clone_flags, p))) |
1da177e4 | 1077 | goto bad_fork_cleanup_keys; |
fadad878 | 1078 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1079 | goto bad_fork_cleanup_namespaces; |
1da177e4 LT |
1080 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); |
1081 | if (retval) | |
fd0928df | 1082 | goto bad_fork_cleanup_io; |
1da177e4 | 1083 | |
425fb2b4 PE |
1084 | if (pid != &init_struct_pid) { |
1085 | retval = -ENOMEM; | |
1086 | pid = alloc_pid(task_active_pid_ns(p)); | |
1087 | if (!pid) | |
fd0928df | 1088 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1089 | |
1090 | if (clone_flags & CLONE_NEWPID) { | |
1091 | retval = pid_ns_prepare_proc(task_active_pid_ns(p)); | |
1092 | if (retval < 0) | |
1093 | goto bad_fork_free_pid; | |
1094 | } | |
425fb2b4 PE |
1095 | } |
1096 | ||
1097 | p->pid = pid_nr(pid); | |
1098 | p->tgid = p->pid; | |
1099 | if (clone_flags & CLONE_THREAD) | |
1100 | p->tgid = current->tgid; | |
1101 | ||
e885dcde SH |
1102 | if (current->nsproxy != p->nsproxy) { |
1103 | retval = ns_cgroup_clone(p, pid); | |
1104 | if (retval) | |
1105 | goto bad_fork_free_pid; | |
1106 | } | |
1107 | ||
1da177e4 LT |
1108 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1109 | /* | |
1110 | * Clear TID on mm_release()? | |
1111 | */ | |
1112 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1113 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1114 | p->robust_list = NULL; |
1115 | #ifdef CONFIG_COMPAT | |
1116 | p->compat_robust_list = NULL; | |
1117 | #endif | |
c87e2837 IM |
1118 | INIT_LIST_HEAD(&p->pi_state_list); |
1119 | p->pi_state_cache = NULL; | |
42b2dd0a | 1120 | #endif |
f9a3879a GM |
1121 | /* |
1122 | * sigaltstack should be cleared when sharing the same VM | |
1123 | */ | |
1124 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1125 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1126 | ||
1da177e4 LT |
1127 | /* |
1128 | * Syscall tracing should be turned off in the child regardless | |
1129 | * of CLONE_PTRACE. | |
1130 | */ | |
1131 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1132 | #ifdef TIF_SYSCALL_EMU |
1133 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1134 | #endif | |
9745512c | 1135 | clear_all_latency_tracing(p); |
1da177e4 LT |
1136 | |
1137 | /* Our parent execution domain becomes current domain | |
1138 | These must match for thread signalling to apply */ | |
1da177e4 LT |
1139 | p->parent_exec_id = p->self_exec_id; |
1140 | ||
1141 | /* ok, now we should be set up.. */ | |
1142 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1143 | p->pdeath_signal = 0; | |
1144 | p->exit_state = 0; | |
1145 | ||
1da177e4 LT |
1146 | /* |
1147 | * Ok, make it visible to the rest of the system. | |
1148 | * We dont wake it up yet. | |
1149 | */ | |
1150 | p->group_leader = p; | |
47e65328 | 1151 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 | 1152 | |
b4f48b63 PM |
1153 | /* Now that the task is set up, run cgroup callbacks if |
1154 | * necessary. We need to run them before the task is visible | |
1155 | * on the tasklist. */ | |
1156 | cgroup_fork_callbacks(p); | |
1157 | cgroup_callbacks_done = 1; | |
1158 | ||
1da177e4 LT |
1159 | /* Need tasklist lock for parent etc handling! */ |
1160 | write_lock_irq(&tasklist_lock); | |
1161 | ||
1162 | /* | |
476d139c NP |
1163 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1164 | * not be changed, nor will its assigned CPU. | |
1165 | * | |
1166 | * The cpus_allowed mask of the parent may have changed after it was | |
1167 | * copied first time - so re-copy it here, then check the child's CPU | |
1168 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1169 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1170 | */ |
1171 | p->cpus_allowed = current->cpus_allowed; | |
6f505b16 | 1172 | p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed; |
26ff6ad9 SV |
1173 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1174 | !cpu_online(task_cpu(p)))) | |
476d139c | 1175 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1176 | |
1da177e4 LT |
1177 | /* CLONE_PARENT re-uses the old parent */ |
1178 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1179 | p->real_parent = current->real_parent; | |
1180 | else | |
1181 | p->real_parent = current; | |
1da177e4 | 1182 | |
3f17da69 | 1183 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1184 | |
1185 | /* | |
1186 | * Process group and session signals need to be delivered to just the | |
1187 | * parent before the fork or both the parent and the child after the | |
1188 | * fork. Restart if a signal comes in before we add the new process to | |
1189 | * it's process group. | |
1190 | * A fatal signal pending means that current will exit, so the new | |
1191 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1192 | */ | |
23ff4440 | 1193 | recalc_sigpending(); |
4a2c7a78 ON |
1194 | if (signal_pending(current)) { |
1195 | spin_unlock(¤t->sighand->siglock); | |
1196 | write_unlock_irq(&tasklist_lock); | |
1197 | retval = -ERESTARTNOINTR; | |
425fb2b4 | 1198 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1199 | } |
1200 | ||
1da177e4 | 1201 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1202 | p->group_leader = current->group_leader; |
47e65328 | 1203 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1204 | |
1da177e4 LT |
1205 | if (!cputime_eq(current->signal->it_virt_expires, |
1206 | cputime_zero) || | |
1207 | !cputime_eq(current->signal->it_prof_expires, | |
1208 | cputime_zero) || | |
1209 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1210 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1211 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1212 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1213 | /* | |
1214 | * Have child wake up on its first tick to check | |
1215 | * for process CPU timers. | |
1216 | */ | |
1217 | p->it_prof_expires = jiffies_to_cputime(1); | |
1218 | } | |
1da177e4 LT |
1219 | } |
1220 | ||
73b9ebfe | 1221 | if (likely(p->pid)) { |
f470021a | 1222 | list_add_tail(&p->sibling, &p->real_parent->children); |
09a05394 | 1223 | tracehook_finish_clone(p, clone_flags, trace); |
73b9ebfe ON |
1224 | |
1225 | if (thread_group_leader(p)) { | |
5cd17569 | 1226 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1227 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1228 | |
fea9d175 | 1229 | p->signal->leader_pid = pid; |
5cd17569 EB |
1230 | p->signal->tty = current->signal->tty; |
1231 | set_task_pgrp(p, task_pgrp_nr(current)); | |
1232 | set_task_session(p, task_session_nr(current)); | |
1233 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); | |
1234 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
5e85d4ab | 1235 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1236 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1237 | } |
85868995 | 1238 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1239 | nr_threads++; |
1da177e4 LT |
1240 | } |
1241 | ||
1da177e4 | 1242 | total_forks++; |
3f17da69 | 1243 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1244 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1245 | proc_fork_connector(p); |
817929ec | 1246 | cgroup_post_fork(p); |
1da177e4 LT |
1247 | return p; |
1248 | ||
425fb2b4 PE |
1249 | bad_fork_free_pid: |
1250 | if (pid != &init_struct_pid) | |
1251 | free_pid(pid); | |
fd0928df JA |
1252 | bad_fork_cleanup_io: |
1253 | put_io_context(p->io_context); | |
ab516013 | 1254 | bad_fork_cleanup_namespaces: |
444f378b | 1255 | exit_task_namespaces(p); |
1da177e4 LT |
1256 | bad_fork_cleanup_keys: |
1257 | exit_keys(p); | |
1258 | bad_fork_cleanup_mm: | |
1259 | if (p->mm) | |
1260 | mmput(p->mm); | |
1261 | bad_fork_cleanup_signal: | |
6b3934ef | 1262 | cleanup_signal(p); |
1da177e4 | 1263 | bad_fork_cleanup_sighand: |
a7e5328a | 1264 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1265 | bad_fork_cleanup_fs: |
1266 | exit_fs(p); /* blocking */ | |
1267 | bad_fork_cleanup_files: | |
1268 | exit_files(p); /* blocking */ | |
1269 | bad_fork_cleanup_semundo: | |
1270 | exit_sem(p); | |
1271 | bad_fork_cleanup_audit: | |
1272 | audit_free(p); | |
1273 | bad_fork_cleanup_security: | |
1274 | security_task_free(p); | |
1275 | bad_fork_cleanup_policy: | |
1276 | #ifdef CONFIG_NUMA | |
f0be3d32 | 1277 | mpol_put(p->mempolicy); |
b4f48b63 | 1278 | bad_fork_cleanup_cgroup: |
1da177e4 | 1279 | #endif |
b4f48b63 | 1280 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1281 | delayacct_tsk_free(p); |
1da177e4 LT |
1282 | if (p->binfmt) |
1283 | module_put(p->binfmt->module); | |
1284 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1285 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1286 | bad_fork_cleanup_count: |
1287 | put_group_info(p->group_info); | |
1288 | atomic_dec(&p->user->processes); | |
1289 | free_uid(p->user); | |
1290 | bad_fork_free: | |
1291 | free_task(p); | |
fe7d37d1 ON |
1292 | fork_out: |
1293 | return ERR_PTR(retval); | |
1da177e4 LT |
1294 | } |
1295 | ||
6b2fb3c6 | 1296 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1297 | { |
1298 | memset(regs, 0, sizeof(struct pt_regs)); | |
1299 | return regs; | |
1300 | } | |
1301 | ||
9abcf40b | 1302 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1303 | { |
36c8b586 | 1304 | struct task_struct *task; |
1da177e4 LT |
1305 | struct pt_regs regs; |
1306 | ||
30e49c26 | 1307 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
09a05394 | 1308 | &init_struct_pid, 0); |
753ca4f3 AM |
1309 | if (!IS_ERR(task)) |
1310 | init_idle(task, cpu); | |
73b9ebfe | 1311 | |
1da177e4 LT |
1312 | return task; |
1313 | } | |
1314 | ||
1da177e4 LT |
1315 | /* |
1316 | * Ok, this is the main fork-routine. | |
1317 | * | |
1318 | * It copies the process, and if successful kick-starts | |
1319 | * it and waits for it to finish using the VM if required. | |
1320 | */ | |
1321 | long do_fork(unsigned long clone_flags, | |
1322 | unsigned long stack_start, | |
1323 | struct pt_regs *regs, | |
1324 | unsigned long stack_size, | |
1325 | int __user *parent_tidptr, | |
1326 | int __user *child_tidptr) | |
1327 | { | |
1328 | struct task_struct *p; | |
1329 | int trace = 0; | |
92476d7f | 1330 | long nr; |
1da177e4 | 1331 | |
bdff746a AM |
1332 | /* |
1333 | * We hope to recycle these flags after 2.6.26 | |
1334 | */ | |
1335 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1336 | static int __read_mostly count = 100; | |
1337 | ||
1338 | if (count > 0 && printk_ratelimit()) { | |
1339 | char comm[TASK_COMM_LEN]; | |
1340 | ||
1341 | count--; | |
1342 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1343 | "clone flags 0x%lx\n", | |
1344 | get_task_comm(comm, current), | |
1345 | clone_flags & CLONE_STOPPED); | |
1346 | } | |
1347 | } | |
1348 | ||
09a05394 RM |
1349 | /* |
1350 | * When called from kernel_thread, don't do user tracing stuff. | |
1351 | */ | |
1352 | if (likely(user_mode(regs))) | |
1353 | trace = tracehook_prepare_clone(clone_flags); | |
1da177e4 | 1354 | |
a6f5e063 | 1355 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
09a05394 | 1356 | child_tidptr, NULL, trace); |
1da177e4 LT |
1357 | /* |
1358 | * Do this prior waking up the new thread - the thread pointer | |
1359 | * might get invalid after that point, if the thread exits quickly. | |
1360 | */ | |
1361 | if (!IS_ERR(p)) { | |
1362 | struct completion vfork; | |
1363 | ||
6c5f3e7b | 1364 | nr = task_pid_vnr(p); |
30e49c26 PE |
1365 | |
1366 | if (clone_flags & CLONE_PARENT_SETTID) | |
1367 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1368 | |
1da177e4 LT |
1369 | if (clone_flags & CLONE_VFORK) { |
1370 | p->vfork_done = &vfork; | |
1371 | init_completion(&vfork); | |
1372 | } | |
1373 | ||
09a05394 RM |
1374 | tracehook_report_clone(trace, regs, clone_flags, nr, p); |
1375 | ||
1376 | /* | |
1377 | * We set PF_STARTING at creation in case tracing wants to | |
1378 | * use this to distinguish a fully live task from one that | |
1379 | * hasn't gotten to tracehook_report_clone() yet. Now we | |
1380 | * clear it and set the child going. | |
1381 | */ | |
1382 | p->flags &= ~PF_STARTING; | |
1383 | ||
1384 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1da177e4 LT |
1385 | /* |
1386 | * We'll start up with an immediate SIGSTOP. | |
1387 | */ | |
1388 | sigaddset(&p->pending.signal, SIGSTOP); | |
1389 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
d9ae90ac | 1390 | __set_task_state(p, TASK_STOPPED); |
09a05394 RM |
1391 | } else { |
1392 | wake_up_new_task(p, clone_flags); | |
1da177e4 LT |
1393 | } |
1394 | ||
09a05394 RM |
1395 | tracehook_report_clone_complete(trace, regs, |
1396 | clone_flags, nr, p); | |
1397 | ||
1da177e4 | 1398 | if (clone_flags & CLONE_VFORK) { |
ba96a0c8 | 1399 | freezer_do_not_count(); |
1da177e4 | 1400 | wait_for_completion(&vfork); |
ba96a0c8 | 1401 | freezer_count(); |
daded34b | 1402 | tracehook_report_vfork_done(p, nr); |
1da177e4 LT |
1403 | } |
1404 | } else { | |
92476d7f | 1405 | nr = PTR_ERR(p); |
1da177e4 | 1406 | } |
92476d7f | 1407 | return nr; |
1da177e4 LT |
1408 | } |
1409 | ||
5fd63b30 RT |
1410 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1411 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1412 | #endif | |
1413 | ||
51cc5068 | 1414 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1415 | { |
1416 | struct sighand_struct *sighand = data; | |
1417 | ||
a35afb83 | 1418 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1419 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1420 | } |
1421 | ||
1da177e4 LT |
1422 | void __init proc_caches_init(void) |
1423 | { | |
1424 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1425 | sizeof(struct sighand_struct), 0, | |
aa1757f9 | 1426 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
20c2df83 | 1427 | sighand_ctor); |
1da177e4 LT |
1428 | signal_cachep = kmem_cache_create("signal_cache", |
1429 | sizeof(struct signal_struct), 0, | |
20c2df83 PM |
1430 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1431 | files_cachep = kmem_cache_create("files_cache", | |
1da177e4 | 1432 | sizeof(struct files_struct), 0, |
20c2df83 PM |
1433 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1434 | fs_cachep = kmem_cache_create("fs_cache", | |
1da177e4 | 1435 | sizeof(struct fs_struct), 0, |
20c2df83 | 1436 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1437 | vm_area_cachep = kmem_cache_create("vm_area_struct", |
1438 | sizeof(struct vm_area_struct), 0, | |
20c2df83 | 1439 | SLAB_PANIC, NULL); |
1da177e4 | 1440 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1441 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
20c2df83 | 1442 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 1443 | } |
cf2e340f | 1444 | |
cf2e340f JD |
1445 | /* |
1446 | * Check constraints on flags passed to the unshare system call and | |
1447 | * force unsharing of additional process context as appropriate. | |
1448 | */ | |
a39bc516 | 1449 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1450 | { |
1451 | /* | |
1452 | * If unsharing a thread from a thread group, must also | |
1453 | * unshare vm. | |
1454 | */ | |
1455 | if (*flags_ptr & CLONE_THREAD) | |
1456 | *flags_ptr |= CLONE_VM; | |
1457 | ||
1458 | /* | |
1459 | * If unsharing vm, must also unshare signal handlers. | |
1460 | */ | |
1461 | if (*flags_ptr & CLONE_VM) | |
1462 | *flags_ptr |= CLONE_SIGHAND; | |
1463 | ||
1464 | /* | |
1465 | * If unsharing signal handlers and the task was created | |
1466 | * using CLONE_THREAD, then must unshare the thread | |
1467 | */ | |
1468 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1469 | (atomic_read(¤t->signal->count) > 1)) | |
1470 | *flags_ptr |= CLONE_THREAD; | |
1471 | ||
1472 | /* | |
1473 | * If unsharing namespace, must also unshare filesystem information. | |
1474 | */ | |
1475 | if (*flags_ptr & CLONE_NEWNS) | |
1476 | *flags_ptr |= CLONE_FS; | |
1477 | } | |
1478 | ||
1479 | /* | |
1480 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1481 | */ | |
1482 | static int unshare_thread(unsigned long unshare_flags) | |
1483 | { | |
1484 | if (unshare_flags & CLONE_THREAD) | |
1485 | return -EINVAL; | |
1486 | ||
1487 | return 0; | |
1488 | } | |
1489 | ||
1490 | /* | |
99d1419d | 1491 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1492 | */ |
1493 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1494 | { | |
1495 | struct fs_struct *fs = current->fs; | |
1496 | ||
1497 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1498 | (fs && atomic_read(&fs->count) > 1)) { |
1499 | *new_fsp = __copy_fs_struct(current->fs); | |
1500 | if (!*new_fsp) | |
1501 | return -ENOMEM; | |
1502 | } | |
cf2e340f JD |
1503 | |
1504 | return 0; | |
1505 | } | |
1506 | ||
cf2e340f | 1507 | /* |
dae3c5a0 | 1508 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1509 | */ |
1510 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1511 | { | |
1512 | struct sighand_struct *sigh = current->sighand; | |
1513 | ||
dae3c5a0 | 1514 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1515 | return -EINVAL; |
1516 | else | |
1517 | return 0; | |
1518 | } | |
1519 | ||
1520 | /* | |
a0a7ec30 | 1521 | * Unshare vm if it is being shared |
cf2e340f JD |
1522 | */ |
1523 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1524 | { | |
1525 | struct mm_struct *mm = current->mm; | |
1526 | ||
1527 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1528 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1529 | return -EINVAL; |
a0a7ec30 | 1530 | } |
cf2e340f JD |
1531 | |
1532 | return 0; | |
cf2e340f JD |
1533 | } |
1534 | ||
1535 | /* | |
a016f338 | 1536 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1537 | */ |
1538 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1539 | { | |
1540 | struct files_struct *fd = current->files; | |
a016f338 | 1541 | int error = 0; |
cf2e340f JD |
1542 | |
1543 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1544 | (fd && atomic_read(&fd->count) > 1)) { |
1545 | *new_fdp = dup_fd(fd, &error); | |
1546 | if (!*new_fdp) | |
1547 | return error; | |
1548 | } | |
cf2e340f JD |
1549 | |
1550 | return 0; | |
1551 | } | |
1552 | ||
cf2e340f JD |
1553 | /* |
1554 | * unshare allows a process to 'unshare' part of the process | |
1555 | * context which was originally shared using clone. copy_* | |
1556 | * functions used by do_fork() cannot be used here directly | |
1557 | * because they modify an inactive task_struct that is being | |
1558 | * constructed. Here we are modifying the current, active, | |
1559 | * task_struct. | |
1560 | */ | |
1561 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1562 | { | |
1563 | int err = 0; | |
1564 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1565 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1566 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1567 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1568 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1569 | int do_sysvsem = 0; |
cf2e340f JD |
1570 | |
1571 | check_unshare_flags(&unshare_flags); | |
1572 | ||
06f9d4f9 EB |
1573 | /* Return -EINVAL for all unsupported flags */ |
1574 | err = -EINVAL; | |
1575 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1576 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
9dd776b6 EB |
1577 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER| |
1578 | CLONE_NEWNET)) | |
06f9d4f9 EB |
1579 | goto bad_unshare_out; |
1580 | ||
6013f67f MS |
1581 | /* |
1582 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1583 | * to a new ipc namespace, the semaphore arrays from the old | |
1584 | * namespace are unreachable. | |
1585 | */ | |
1586 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1587 | do_sysvsem = 1; |
cf2e340f JD |
1588 | if ((err = unshare_thread(unshare_flags))) |
1589 | goto bad_unshare_out; | |
1590 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1591 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1592 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1593 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1594 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1595 | goto bad_unshare_cleanup_sigh; | |
1596 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1597 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1598 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1599 | new_fs))) | |
9edff4ab | 1600 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1601 | |
9edff4ab MS |
1602 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1603 | if (do_sysvsem) { | |
1604 | /* | |
1605 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1606 | */ | |
1607 | exit_sem(current); | |
1608 | } | |
ab516013 | 1609 | |
c0b2fc31 | 1610 | if (new_nsproxy) { |
cf7b708c PE |
1611 | switch_task_namespaces(current, new_nsproxy); |
1612 | new_nsproxy = NULL; | |
c0b2fc31 | 1613 | } |
cf2e340f | 1614 | |
cf7b708c PE |
1615 | task_lock(current); |
1616 | ||
cf2e340f JD |
1617 | if (new_fs) { |
1618 | fs = current->fs; | |
1619 | current->fs = new_fs; | |
1620 | new_fs = fs; | |
1621 | } | |
1622 | ||
cf2e340f JD |
1623 | if (new_mm) { |
1624 | mm = current->mm; | |
1625 | active_mm = current->active_mm; | |
1626 | current->mm = new_mm; | |
1627 | current->active_mm = new_mm; | |
1628 | activate_mm(active_mm, new_mm); | |
1629 | new_mm = mm; | |
1630 | } | |
1631 | ||
1632 | if (new_fd) { | |
1633 | fd = current->files; | |
1634 | current->files = new_fd; | |
1635 | new_fd = fd; | |
1636 | } | |
1637 | ||
1638 | task_unlock(current); | |
1639 | } | |
1640 | ||
c0b2fc31 | 1641 | if (new_nsproxy) |
444f378b | 1642 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1643 | |
cf2e340f JD |
1644 | bad_unshare_cleanup_fd: |
1645 | if (new_fd) | |
1646 | put_files_struct(new_fd); | |
1647 | ||
1648 | bad_unshare_cleanup_vm: | |
1649 | if (new_mm) | |
1650 | mmput(new_mm); | |
1651 | ||
1652 | bad_unshare_cleanup_sigh: | |
1653 | if (new_sigh) | |
1654 | if (atomic_dec_and_test(&new_sigh->count)) | |
1655 | kmem_cache_free(sighand_cachep, new_sigh); | |
1656 | ||
cf2e340f JD |
1657 | bad_unshare_cleanup_fs: |
1658 | if (new_fs) | |
1659 | put_fs_struct(new_fs); | |
1660 | ||
1661 | bad_unshare_cleanup_thread: | |
1662 | bad_unshare_out: | |
1663 | return err; | |
1664 | } | |
3b125388 AV |
1665 | |
1666 | /* | |
1667 | * Helper to unshare the files of the current task. | |
1668 | * We don't want to expose copy_files internals to | |
1669 | * the exec layer of the kernel. | |
1670 | */ | |
1671 | ||
1672 | int unshare_files(struct files_struct **displaced) | |
1673 | { | |
1674 | struct task_struct *task = current; | |
50704516 | 1675 | struct files_struct *copy = NULL; |
3b125388 AV |
1676 | int error; |
1677 | ||
1678 | error = unshare_fd(CLONE_FILES, ©); | |
1679 | if (error || !copy) { | |
1680 | *displaced = NULL; | |
1681 | return error; | |
1682 | } | |
1683 | *displaced = task->files; | |
1684 | task_lock(task); | |
1685 | task->files = copy; | |
1686 | task_unlock(task); | |
1687 | return 0; | |
1688 | } |