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> |
0a16b607 | 61 | #include <trace/sched.h> |
1da177e4 LT |
62 | |
63 | #include <asm/pgtable.h> | |
64 | #include <asm/pgalloc.h> | |
65 | #include <asm/uaccess.h> | |
66 | #include <asm/mmu_context.h> | |
67 | #include <asm/cacheflush.h> | |
68 | #include <asm/tlbflush.h> | |
69 | ||
70 | /* | |
71 | * Protected counters by write_lock_irq(&tasklist_lock) | |
72 | */ | |
73 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
74 | int nr_threads; /* The idle threads do not count.. */ | |
75 | ||
76 | int max_threads; /* tunable limit on nr_threads */ | |
77 | ||
78 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
79 | ||
c59923a1 | 80 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 LT |
81 | |
82 | int nr_processes(void) | |
83 | { | |
84 | int cpu; | |
85 | int total = 0; | |
86 | ||
87 | for_each_online_cpu(cpu) | |
88 | total += per_cpu(process_counts, cpu); | |
89 | ||
90 | return total; | |
91 | } | |
92 | ||
93 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
94 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
95 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 96 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
97 | #endif |
98 | ||
b69c49b7 FT |
99 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
100 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) | |
101 | { | |
102 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
103 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; | |
104 | #else | |
105 | gfp_t mask = GFP_KERNEL; | |
106 | #endif | |
107 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); | |
108 | } | |
109 | ||
110 | static inline void free_thread_info(struct thread_info *ti) | |
111 | { | |
112 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); | |
113 | } | |
114 | #endif | |
115 | ||
1da177e4 | 116 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 117 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
118 | |
119 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 120 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
121 | |
122 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 123 | struct kmem_cache *files_cachep; |
1da177e4 LT |
124 | |
125 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 126 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
127 | |
128 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 129 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
130 | |
131 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 132 | static struct kmem_cache *mm_cachep; |
1da177e4 LT |
133 | |
134 | void free_task(struct task_struct *tsk) | |
135 | { | |
3e26c149 | 136 | prop_local_destroy_single(&tsk->dirties); |
f7e4217b | 137 | free_thread_info(tsk->stack); |
23f78d4a | 138 | rt_mutex_debug_task_free(tsk); |
1da177e4 LT |
139 | free_task_struct(tsk); |
140 | } | |
141 | EXPORT_SYMBOL(free_task); | |
142 | ||
158d9ebd | 143 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 144 | { |
270f722d | 145 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
146 | WARN_ON(atomic_read(&tsk->usage)); |
147 | WARN_ON(tsk == current); | |
148 | ||
1da177e4 LT |
149 | security_task_free(tsk); |
150 | free_uid(tsk->user); | |
151 | put_group_info(tsk->group_info); | |
35df17c5 | 152 | delayacct_tsk_free(tsk); |
1da177e4 LT |
153 | |
154 | if (!profile_handoff_task(tsk)) | |
155 | free_task(tsk); | |
156 | } | |
157 | ||
2adee9b3 SS |
158 | /* |
159 | * macro override instead of weak attribute alias, to workaround | |
160 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
161 | */ | |
162 | #ifndef arch_task_cache_init | |
163 | #define arch_task_cache_init() | |
164 | #endif | |
61c4628b | 165 | |
1da177e4 LT |
166 | void __init fork_init(unsigned long mempages) |
167 | { | |
168 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
169 | #ifndef ARCH_MIN_TASKALIGN | |
170 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
171 | #endif | |
172 | /* create a slab on which task_structs can be allocated */ | |
173 | task_struct_cachep = | |
174 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
20c2df83 | 175 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL); |
1da177e4 LT |
176 | #endif |
177 | ||
61c4628b SS |
178 | /* do the arch specific task caches init */ |
179 | arch_task_cache_init(); | |
180 | ||
1da177e4 LT |
181 | /* |
182 | * The default maximum number of threads is set to a safe | |
183 | * value: the thread structures can take up at most half | |
184 | * of memory. | |
185 | */ | |
186 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
187 | ||
188 | /* | |
189 | * we need to allow at least 20 threads to boot a system | |
190 | */ | |
191 | if(max_threads < 20) | |
192 | max_threads = 20; | |
193 | ||
194 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
195 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
196 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
197 | init_task.signal->rlim[RLIMIT_NPROC]; | |
198 | } | |
199 | ||
61c4628b SS |
200 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
201 | struct task_struct *src) | |
202 | { | |
203 | *dst = *src; | |
204 | return 0; | |
205 | } | |
206 | ||
1da177e4 LT |
207 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
208 | { | |
209 | struct task_struct *tsk; | |
210 | struct thread_info *ti; | |
3e26c149 | 211 | int err; |
1da177e4 LT |
212 | |
213 | prepare_to_copy(orig); | |
214 | ||
215 | tsk = alloc_task_struct(); | |
216 | if (!tsk) | |
217 | return NULL; | |
218 | ||
219 | ti = alloc_thread_info(tsk); | |
220 | if (!ti) { | |
221 | free_task_struct(tsk); | |
222 | return NULL; | |
223 | } | |
224 | ||
61c4628b SS |
225 | err = arch_dup_task_struct(tsk, orig); |
226 | if (err) | |
227 | goto out; | |
228 | ||
f7e4217b | 229 | tsk->stack = ti; |
3e26c149 PZ |
230 | |
231 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
232 | if (err) |
233 | goto out; | |
3e26c149 | 234 | |
10ebffde | 235 | setup_thread_stack(tsk, orig); |
1da177e4 | 236 | |
0a425405 AV |
237 | #ifdef CONFIG_CC_STACKPROTECTOR |
238 | tsk->stack_canary = get_random_int(); | |
239 | #endif | |
240 | ||
1da177e4 LT |
241 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
242 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 243 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 244 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 245 | tsk->btrace_seq = 0; |
6c5c9341 | 246 | #endif |
a0aa7f68 | 247 | tsk->splice_pipe = NULL; |
1da177e4 | 248 | return tsk; |
61c4628b SS |
249 | |
250 | out: | |
251 | free_thread_info(ti); | |
252 | free_task_struct(tsk); | |
253 | return NULL; | |
1da177e4 LT |
254 | } |
255 | ||
256 | #ifdef CONFIG_MMU | |
a39bc516 | 257 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 258 | { |
fd3e42fc | 259 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
260 | struct rb_node **rb_link, *rb_parent; |
261 | int retval; | |
262 | unsigned long charge; | |
263 | struct mempolicy *pol; | |
264 | ||
265 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 266 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
267 | /* |
268 | * Not linked in yet - no deadlock potential: | |
269 | */ | |
270 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 271 | |
1da177e4 LT |
272 | mm->locked_vm = 0; |
273 | mm->mmap = NULL; | |
274 | mm->mmap_cache = NULL; | |
275 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 276 | mm->cached_hole_size = ~0UL; |
1da177e4 | 277 | mm->map_count = 0; |
1da177e4 LT |
278 | cpus_clear(mm->cpu_vm_mask); |
279 | mm->mm_rb = RB_ROOT; | |
280 | rb_link = &mm->mm_rb.rb_node; | |
281 | rb_parent = NULL; | |
282 | pprev = &mm->mmap; | |
283 | ||
fd3e42fc | 284 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
285 | struct file *file; |
286 | ||
287 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
288 | long pages = vma_pages(mpnt); |
289 | mm->total_vm -= pages; | |
ab50b8ed | 290 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 291 | -pages); |
1da177e4 LT |
292 | continue; |
293 | } | |
294 | charge = 0; | |
295 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
296 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
297 | if (security_vm_enough_memory(len)) | |
298 | goto fail_nomem; | |
299 | charge = len; | |
300 | } | |
e94b1766 | 301 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
302 | if (!tmp) |
303 | goto fail_nomem; | |
304 | *tmp = *mpnt; | |
846a16bf | 305 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
306 | retval = PTR_ERR(pol); |
307 | if (IS_ERR(pol)) | |
308 | goto fail_nomem_policy; | |
309 | vma_set_policy(tmp, pol); | |
310 | tmp->vm_flags &= ~VM_LOCKED; | |
311 | tmp->vm_mm = mm; | |
312 | tmp->vm_next = NULL; | |
313 | anon_vma_link(tmp); | |
314 | file = tmp->vm_file; | |
315 | if (file) { | |
f3a43f3f | 316 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
317 | get_file(file); |
318 | if (tmp->vm_flags & VM_DENYWRITE) | |
319 | atomic_dec(&inode->i_writecount); | |
23ff4440 | 320 | |
1da177e4 LT |
321 | /* insert tmp into the share list, just after mpnt */ |
322 | spin_lock(&file->f_mapping->i_mmap_lock); | |
323 | tmp->vm_truncate_count = mpnt->vm_truncate_count; | |
324 | flush_dcache_mmap_lock(file->f_mapping); | |
325 | vma_prio_tree_add(tmp, mpnt); | |
326 | flush_dcache_mmap_unlock(file->f_mapping); | |
327 | spin_unlock(&file->f_mapping->i_mmap_lock); | |
328 | } | |
329 | ||
a1e78772 MG |
330 | /* |
331 | * Clear hugetlb-related page reserves for children. This only | |
332 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
333 | * are not guaranteed to succeed, even if read-only | |
334 | */ | |
335 | if (is_vm_hugetlb_page(tmp)) | |
336 | reset_vma_resv_huge_pages(tmp); | |
337 | ||
1da177e4 | 338 | /* |
7ee78232 | 339 | * Link in the new vma and copy the page table entries. |
1da177e4 | 340 | */ |
1da177e4 LT |
341 | *pprev = tmp; |
342 | pprev = &tmp->vm_next; | |
343 | ||
344 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
345 | rb_link = &tmp->vm_rb.rb_right; | |
346 | rb_parent = &tmp->vm_rb; | |
347 | ||
348 | mm->map_count++; | |
0b0db14c | 349 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
350 | |
351 | if (tmp->vm_ops && tmp->vm_ops->open) | |
352 | tmp->vm_ops->open(tmp); | |
353 | ||
354 | if (retval) | |
355 | goto out; | |
356 | } | |
d6dd61c8 JF |
357 | /* a new mm has just been created */ |
358 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 359 | retval = 0; |
1da177e4 | 360 | out: |
7ee78232 | 361 | up_write(&mm->mmap_sem); |
fd3e42fc | 362 | flush_tlb_mm(oldmm); |
1da177e4 LT |
363 | up_write(&oldmm->mmap_sem); |
364 | return retval; | |
365 | fail_nomem_policy: | |
366 | kmem_cache_free(vm_area_cachep, tmp); | |
367 | fail_nomem: | |
368 | retval = -ENOMEM; | |
369 | vm_unacct_memory(charge); | |
370 | goto out; | |
371 | } | |
372 | ||
373 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
374 | { | |
375 | mm->pgd = pgd_alloc(mm); | |
376 | if (unlikely(!mm->pgd)) | |
377 | return -ENOMEM; | |
378 | return 0; | |
379 | } | |
380 | ||
381 | static inline void mm_free_pgd(struct mm_struct * mm) | |
382 | { | |
5e541973 | 383 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
384 | } |
385 | #else | |
386 | #define dup_mmap(mm, oldmm) (0) | |
387 | #define mm_alloc_pgd(mm) (0) | |
388 | #define mm_free_pgd(mm) | |
389 | #endif /* CONFIG_MMU */ | |
390 | ||
23ff4440 | 391 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 392 | |
e94b1766 | 393 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
394 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
395 | ||
396 | #include <linux/init_task.h> | |
397 | ||
78fb7466 | 398 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
399 | { |
400 | atomic_set(&mm->mm_users, 1); | |
401 | atomic_set(&mm->mm_count, 1); | |
402 | init_rwsem(&mm->mmap_sem); | |
403 | INIT_LIST_HEAD(&mm->mmlist); | |
3cb4a0bb KH |
404 | mm->flags = (current->mm) ? current->mm->flags |
405 | : MMF_DUMP_FILTER_DEFAULT; | |
999d9fc1 | 406 | mm->core_state = NULL; |
1da177e4 | 407 | mm->nr_ptes = 0; |
4294621f | 408 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 409 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 LT |
410 | spin_lock_init(&mm->page_table_lock); |
411 | rwlock_init(&mm->ioctx_list_lock); | |
412 | mm->ioctx_list = NULL; | |
1da177e4 | 413 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 414 | mm->cached_hole_size = ~0UL; |
cf475ad2 | 415 | mm_init_owner(mm, p); |
1da177e4 LT |
416 | |
417 | if (likely(!mm_alloc_pgd(mm))) { | |
418 | mm->def_flags = 0; | |
cddb8a5c | 419 | mmu_notifier_mm_init(mm); |
1da177e4 LT |
420 | return mm; |
421 | } | |
78fb7466 | 422 | |
1da177e4 LT |
423 | free_mm(mm); |
424 | return NULL; | |
425 | } | |
426 | ||
427 | /* | |
428 | * Allocate and initialize an mm_struct. | |
429 | */ | |
430 | struct mm_struct * mm_alloc(void) | |
431 | { | |
432 | struct mm_struct * mm; | |
433 | ||
434 | mm = allocate_mm(); | |
435 | if (mm) { | |
436 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 437 | mm = mm_init(mm, current); |
1da177e4 LT |
438 | } |
439 | return mm; | |
440 | } | |
441 | ||
442 | /* | |
443 | * Called when the last reference to the mm | |
444 | * is dropped: either by a lazy thread or by | |
445 | * mmput. Free the page directory and the mm. | |
446 | */ | |
7ad5b3a5 | 447 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
448 | { |
449 | BUG_ON(mm == &init_mm); | |
450 | mm_free_pgd(mm); | |
451 | destroy_context(mm); | |
cddb8a5c | 452 | mmu_notifier_mm_destroy(mm); |
1da177e4 LT |
453 | free_mm(mm); |
454 | } | |
6d4e4c4f | 455 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
456 | |
457 | /* | |
458 | * Decrement the use count and release all resources for an mm. | |
459 | */ | |
460 | void mmput(struct mm_struct *mm) | |
461 | { | |
0ae26f1b AM |
462 | might_sleep(); |
463 | ||
1da177e4 LT |
464 | if (atomic_dec_and_test(&mm->mm_users)) { |
465 | exit_aio(mm); | |
466 | exit_mmap(mm); | |
925d1c40 | 467 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
468 | if (!list_empty(&mm->mmlist)) { |
469 | spin_lock(&mmlist_lock); | |
470 | list_del(&mm->mmlist); | |
471 | spin_unlock(&mmlist_lock); | |
472 | } | |
473 | put_swap_token(mm); | |
474 | mmdrop(mm); | |
475 | } | |
476 | } | |
477 | EXPORT_SYMBOL_GPL(mmput); | |
478 | ||
479 | /** | |
480 | * get_task_mm - acquire a reference to the task's mm | |
481 | * | |
246bb0b1 | 482 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
483 | * this kernel workthread has transiently adopted a user mm with use_mm, |
484 | * to do its AIO) is not set and if so returns a reference to it, after | |
485 | * bumping up the use count. User must release the mm via mmput() | |
486 | * after use. Typically used by /proc and ptrace. | |
487 | */ | |
488 | struct mm_struct *get_task_mm(struct task_struct *task) | |
489 | { | |
490 | struct mm_struct *mm; | |
491 | ||
492 | task_lock(task); | |
493 | mm = task->mm; | |
494 | if (mm) { | |
246bb0b1 | 495 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
496 | mm = NULL; |
497 | else | |
498 | atomic_inc(&mm->mm_users); | |
499 | } | |
500 | task_unlock(task); | |
501 | return mm; | |
502 | } | |
503 | EXPORT_SYMBOL_GPL(get_task_mm); | |
504 | ||
505 | /* Please note the differences between mmput and mm_release. | |
506 | * mmput is called whenever we stop holding onto a mm_struct, | |
507 | * error success whatever. | |
508 | * | |
509 | * mm_release is called after a mm_struct has been removed | |
510 | * from the current process. | |
511 | * | |
512 | * This difference is important for error handling, when we | |
513 | * only half set up a mm_struct for a new process and need to restore | |
514 | * the old one. Because we mmput the new mm_struct before | |
515 | * restoring the old one. . . | |
516 | * Eric Biederman 10 January 1998 | |
517 | */ | |
518 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
519 | { | |
520 | struct completion *vfork_done = tsk->vfork_done; | |
521 | ||
522 | /* Get rid of any cached register state */ | |
523 | deactivate_mm(tsk, mm); | |
524 | ||
525 | /* notify parent sleeping on vfork() */ | |
526 | if (vfork_done) { | |
527 | tsk->vfork_done = NULL; | |
528 | complete(vfork_done); | |
529 | } | |
fec1d011 RM |
530 | |
531 | /* | |
532 | * If we're exiting normally, clear a user-space tid field if | |
533 | * requested. We leave this alone when dying by signal, to leave | |
534 | * the value intact in a core dump, and to save the unnecessary | |
535 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
536 | */ | |
537 | if (tsk->clear_child_tid | |
538 | && !(tsk->flags & PF_SIGNALED) | |
539 | && atomic_read(&mm->mm_users) > 1) { | |
1da177e4 LT |
540 | u32 __user * tidptr = tsk->clear_child_tid; |
541 | tsk->clear_child_tid = NULL; | |
542 | ||
543 | /* | |
544 | * We don't check the error code - if userspace has | |
545 | * not set up a proper pointer then tough luck. | |
546 | */ | |
547 | put_user(0, tidptr); | |
548 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
549 | } | |
550 | } | |
551 | ||
a0a7ec30 JD |
552 | /* |
553 | * Allocate a new mm structure and copy contents from the | |
554 | * mm structure of the passed in task structure. | |
555 | */ | |
402b0862 | 556 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
557 | { |
558 | struct mm_struct *mm, *oldmm = current->mm; | |
559 | int err; | |
560 | ||
561 | if (!oldmm) | |
562 | return NULL; | |
563 | ||
564 | mm = allocate_mm(); | |
565 | if (!mm) | |
566 | goto fail_nomem; | |
567 | ||
568 | memcpy(mm, oldmm, sizeof(*mm)); | |
569 | ||
7602bdf2 AC |
570 | /* Initializing for Swap token stuff */ |
571 | mm->token_priority = 0; | |
572 | mm->last_interval = 0; | |
573 | ||
78fb7466 | 574 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
575 | goto fail_nomem; |
576 | ||
577 | if (init_new_context(tsk, mm)) | |
578 | goto fail_nocontext; | |
579 | ||
925d1c40 MH |
580 | dup_mm_exe_file(oldmm, mm); |
581 | ||
a0a7ec30 JD |
582 | err = dup_mmap(mm, oldmm); |
583 | if (err) | |
584 | goto free_pt; | |
585 | ||
586 | mm->hiwater_rss = get_mm_rss(mm); | |
587 | mm->hiwater_vm = mm->total_vm; | |
588 | ||
589 | return mm; | |
590 | ||
591 | free_pt: | |
592 | mmput(mm); | |
593 | ||
594 | fail_nomem: | |
595 | return NULL; | |
596 | ||
597 | fail_nocontext: | |
598 | /* | |
599 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
600 | * because it calls destroy_context() | |
601 | */ | |
602 | mm_free_pgd(mm); | |
603 | free_mm(mm); | |
604 | return NULL; | |
605 | } | |
606 | ||
1da177e4 LT |
607 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
608 | { | |
609 | struct mm_struct * mm, *oldmm; | |
610 | int retval; | |
611 | ||
612 | tsk->min_flt = tsk->maj_flt = 0; | |
613 | tsk->nvcsw = tsk->nivcsw = 0; | |
614 | ||
615 | tsk->mm = NULL; | |
616 | tsk->active_mm = NULL; | |
617 | ||
618 | /* | |
619 | * Are we cloning a kernel thread? | |
620 | * | |
621 | * We need to steal a active VM for that.. | |
622 | */ | |
623 | oldmm = current->mm; | |
624 | if (!oldmm) | |
625 | return 0; | |
626 | ||
627 | if (clone_flags & CLONE_VM) { | |
628 | atomic_inc(&oldmm->mm_users); | |
629 | mm = oldmm; | |
1da177e4 LT |
630 | goto good_mm; |
631 | } | |
632 | ||
633 | retval = -ENOMEM; | |
a0a7ec30 | 634 | mm = dup_mm(tsk); |
1da177e4 LT |
635 | if (!mm) |
636 | goto fail_nomem; | |
637 | ||
1da177e4 | 638 | good_mm: |
7602bdf2 AC |
639 | /* Initializing for Swap token stuff */ |
640 | mm->token_priority = 0; | |
641 | mm->last_interval = 0; | |
642 | ||
1da177e4 LT |
643 | tsk->mm = mm; |
644 | tsk->active_mm = mm; | |
645 | return 0; | |
646 | ||
1da177e4 LT |
647 | fail_nomem: |
648 | return retval; | |
1da177e4 LT |
649 | } |
650 | ||
a39bc516 | 651 | static struct fs_struct *__copy_fs_struct(struct fs_struct *old) |
1da177e4 LT |
652 | { |
653 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); | |
654 | /* We don't need to lock fs - think why ;-) */ | |
655 | if (fs) { | |
656 | atomic_set(&fs->count, 1); | |
657 | rwlock_init(&fs->lock); | |
658 | fs->umask = old->umask; | |
659 | read_lock(&old->lock); | |
6ac08c39 JB |
660 | fs->root = old->root; |
661 | path_get(&old->root); | |
662 | fs->pwd = old->pwd; | |
663 | path_get(&old->pwd); | |
1da177e4 LT |
664 | read_unlock(&old->lock); |
665 | } | |
666 | return fs; | |
667 | } | |
668 | ||
669 | struct fs_struct *copy_fs_struct(struct fs_struct *old) | |
670 | { | |
671 | return __copy_fs_struct(old); | |
672 | } | |
673 | ||
674 | EXPORT_SYMBOL_GPL(copy_fs_struct); | |
675 | ||
a39bc516 | 676 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
677 | { |
678 | if (clone_flags & CLONE_FS) { | |
679 | atomic_inc(¤t->fs->count); | |
680 | return 0; | |
681 | } | |
682 | tsk->fs = __copy_fs_struct(current->fs); | |
683 | if (!tsk->fs) | |
684 | return -ENOMEM; | |
685 | return 0; | |
686 | } | |
687 | ||
a016f338 JD |
688 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
689 | { | |
690 | struct files_struct *oldf, *newf; | |
691 | int error = 0; | |
692 | ||
693 | /* | |
694 | * A background process may not have any files ... | |
695 | */ | |
696 | oldf = current->files; | |
697 | if (!oldf) | |
698 | goto out; | |
699 | ||
700 | if (clone_flags & CLONE_FILES) { | |
701 | atomic_inc(&oldf->count); | |
702 | goto out; | |
703 | } | |
704 | ||
a016f338 JD |
705 | newf = dup_fd(oldf, &error); |
706 | if (!newf) | |
707 | goto out; | |
708 | ||
709 | tsk->files = newf; | |
710 | error = 0; | |
711 | out: | |
712 | return error; | |
713 | } | |
714 | ||
fadad878 | 715 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
716 | { |
717 | #ifdef CONFIG_BLOCK | |
718 | struct io_context *ioc = current->io_context; | |
719 | ||
720 | if (!ioc) | |
721 | return 0; | |
fadad878 JA |
722 | /* |
723 | * Share io context with parent, if CLONE_IO is set | |
724 | */ | |
725 | if (clone_flags & CLONE_IO) { | |
726 | tsk->io_context = ioc_task_link(ioc); | |
727 | if (unlikely(!tsk->io_context)) | |
728 | return -ENOMEM; | |
729 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
730 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
731 | if (unlikely(!tsk->io_context)) | |
732 | return -ENOMEM; | |
733 | ||
fd0928df JA |
734 | tsk->io_context->ioprio = ioc->ioprio; |
735 | } | |
736 | #endif | |
737 | return 0; | |
738 | } | |
739 | ||
a39bc516 | 740 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
741 | { |
742 | struct sighand_struct *sig; | |
743 | ||
744 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { | |
745 | atomic_inc(¤t->sighand->count); | |
746 | return 0; | |
747 | } | |
748 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 749 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
750 | if (!sig) |
751 | return -ENOMEM; | |
1da177e4 LT |
752 | atomic_set(&sig->count, 1); |
753 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
754 | return 0; | |
755 | } | |
756 | ||
a7e5328a | 757 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 758 | { |
c81addc9 ON |
759 | if (atomic_dec_and_test(&sighand->count)) |
760 | kmem_cache_free(sighand_cachep, sighand); | |
761 | } | |
762 | ||
a39bc516 | 763 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
764 | { |
765 | struct signal_struct *sig; | |
766 | int ret; | |
767 | ||
768 | if (clone_flags & CLONE_THREAD) { | |
769 | atomic_inc(¤t->signal->count); | |
770 | atomic_inc(¤t->signal->live); | |
771 | return 0; | |
772 | } | |
773 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
774 | tsk->signal = sig; | |
775 | if (!sig) | |
776 | return -ENOMEM; | |
777 | ||
778 | ret = copy_thread_group_keys(tsk); | |
779 | if (ret < 0) { | |
780 | kmem_cache_free(signal_cachep, sig); | |
781 | return ret; | |
782 | } | |
783 | ||
784 | atomic_set(&sig->count, 1); | |
785 | atomic_set(&sig->live, 1); | |
786 | init_waitqueue_head(&sig->wait_chldexit); | |
787 | sig->flags = 0; | |
788 | sig->group_exit_code = 0; | |
789 | sig->group_exit_task = NULL; | |
790 | sig->group_stop_count = 0; | |
db51aecc | 791 | sig->curr_target = tsk; |
1da177e4 LT |
792 | init_sigpending(&sig->shared_pending); |
793 | INIT_LIST_HEAD(&sig->posix_timers); | |
794 | ||
c9cb2e3d | 795 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
2ff678b8 | 796 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 797 | sig->real_timer.function = it_real_fn; |
1da177e4 LT |
798 | |
799 | sig->it_virt_expires = cputime_zero; | |
800 | sig->it_virt_incr = cputime_zero; | |
801 | sig->it_prof_expires = cputime_zero; | |
802 | sig->it_prof_incr = cputime_zero; | |
803 | ||
1da177e4 | 804 | sig->leader = 0; /* session leadership doesn't inherit */ |
ab521dc0 | 805 | sig->tty_old_pgrp = NULL; |
9c9f4ded | 806 | sig->tty = NULL; |
1da177e4 LT |
807 | |
808 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; | |
9ac52315 LV |
809 | sig->gtime = cputime_zero; |
810 | sig->cgtime = cputime_zero; | |
1da177e4 LT |
811 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
812 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
6eaeeaba | 813 | sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; |
5995477a | 814 | task_io_accounting_init(&sig->ioac); |
172ba844 | 815 | sig->sum_sched_runtime = 0; |
1da177e4 LT |
816 | INIT_LIST_HEAD(&sig->cpu_timers[0]); |
817 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
818 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
ad4ecbcb | 819 | taskstats_tgid_init(sig); |
1da177e4 LT |
820 | |
821 | task_lock(current->group_leader); | |
822 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
823 | task_unlock(current->group_leader); | |
824 | ||
825 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { | |
826 | /* | |
827 | * New sole thread in the process gets an expiry time | |
828 | * of the whole CPU time limit. | |
829 | */ | |
830 | tsk->it_prof_expires = | |
831 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); | |
832 | } | |
0e464814 | 833 | acct_init_pacct(&sig->pacct); |
1da177e4 | 834 | |
522ed776 MT |
835 | tty_audit_fork(sig); |
836 | ||
1da177e4 LT |
837 | return 0; |
838 | } | |
839 | ||
6b3934ef ON |
840 | void __cleanup_signal(struct signal_struct *sig) |
841 | { | |
842 | exit_thread_group_keys(sig); | |
9c9f4ded | 843 | tty_kref_put(sig->tty); |
6b3934ef ON |
844 | kmem_cache_free(signal_cachep, sig); |
845 | } | |
846 | ||
a39bc516 | 847 | static void cleanup_signal(struct task_struct *tsk) |
6b3934ef ON |
848 | { |
849 | struct signal_struct *sig = tsk->signal; | |
850 | ||
851 | atomic_dec(&sig->live); | |
852 | ||
853 | if (atomic_dec_and_test(&sig->count)) | |
854 | __cleanup_signal(sig); | |
855 | } | |
856 | ||
a39bc516 | 857 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
858 | { |
859 | unsigned long new_flags = p->flags; | |
860 | ||
83144186 | 861 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 | 862 | new_flags |= PF_FORKNOEXEC; |
09a05394 | 863 | new_flags |= PF_STARTING; |
1da177e4 | 864 | p->flags = new_flags; |
2e131895 | 865 | clear_freeze_flag(p); |
1da177e4 LT |
866 | } |
867 | ||
868 | asmlinkage long sys_set_tid_address(int __user *tidptr) | |
869 | { | |
870 | current->clear_child_tid = tidptr; | |
871 | ||
b488893a | 872 | return task_pid_vnr(current); |
1da177e4 LT |
873 | } |
874 | ||
a39bc516 | 875 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 876 | { |
23f78d4a | 877 | spin_lock_init(&p->pi_lock); |
e29e175b | 878 | #ifdef CONFIG_RT_MUTEXES |
23f78d4a IM |
879 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
880 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
881 | #endif |
882 | } | |
883 | ||
cf475ad2 BS |
884 | #ifdef CONFIG_MM_OWNER |
885 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
886 | { | |
887 | mm->owner = p; | |
888 | } | |
889 | #endif /* CONFIG_MM_OWNER */ | |
890 | ||
1da177e4 LT |
891 | /* |
892 | * This creates a new process as a copy of the old one, | |
893 | * but does not actually start it yet. | |
894 | * | |
895 | * It copies the registers, and all the appropriate | |
896 | * parts of the process environment (as per the clone | |
897 | * flags). The actual kick-off is left to the caller. | |
898 | */ | |
36c8b586 IM |
899 | static struct task_struct *copy_process(unsigned long clone_flags, |
900 | unsigned long stack_start, | |
901 | struct pt_regs *regs, | |
902 | unsigned long stack_size, | |
36c8b586 | 903 | int __user *child_tidptr, |
09a05394 RM |
904 | struct pid *pid, |
905 | int trace) | |
1da177e4 LT |
906 | { |
907 | int retval; | |
a24efe62 | 908 | struct task_struct *p; |
b4f48b63 | 909 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
910 | |
911 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
912 | return ERR_PTR(-EINVAL); | |
913 | ||
914 | /* | |
915 | * Thread groups must share signals as well, and detached threads | |
916 | * can only be started up within the thread group. | |
917 | */ | |
918 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
919 | return ERR_PTR(-EINVAL); | |
920 | ||
921 | /* | |
922 | * Shared signal handlers imply shared VM. By way of the above, | |
923 | * thread groups also imply shared VM. Blocking this case allows | |
924 | * for various simplifications in other code. | |
925 | */ | |
926 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
927 | return ERR_PTR(-EINVAL); | |
928 | ||
929 | retval = security_task_create(clone_flags); | |
930 | if (retval) | |
931 | goto fork_out; | |
932 | ||
933 | retval = -ENOMEM; | |
934 | p = dup_task_struct(current); | |
935 | if (!p) | |
936 | goto fork_out; | |
937 | ||
bea493a0 PZ |
938 | rt_mutex_init_task(p); |
939 | ||
d12c1a37 | 940 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
941 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
942 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
943 | #endif | |
1da177e4 LT |
944 | retval = -EAGAIN; |
945 | if (atomic_read(&p->user->processes) >= | |
946 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { | |
947 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
acce292c | 948 | p->user != current->nsproxy->user_ns->root_user) |
1da177e4 LT |
949 | goto bad_fork_free; |
950 | } | |
951 | ||
952 | atomic_inc(&p->user->__count); | |
953 | atomic_inc(&p->user->processes); | |
954 | get_group_info(p->group_info); | |
955 | ||
956 | /* | |
957 | * If multiple threads are within copy_process(), then this check | |
958 | * triggers too late. This doesn't hurt, the check is only there | |
959 | * to stop root fork bombs. | |
960 | */ | |
961 | if (nr_threads >= max_threads) | |
962 | goto bad_fork_cleanup_count; | |
963 | ||
a1261f54 | 964 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
965 | goto bad_fork_cleanup_count; |
966 | ||
967 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
968 | goto bad_fork_cleanup_put_domain; | |
969 | ||
970 | p->did_exec = 0; | |
ca74e92b | 971 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 972 | copy_flags(clone_flags, p); |
1da177e4 LT |
973 | INIT_LIST_HEAD(&p->children); |
974 | INIT_LIST_HEAD(&p->sibling); | |
e260be67 PM |
975 | #ifdef CONFIG_PREEMPT_RCU |
976 | p->rcu_read_lock_nesting = 0; | |
977 | p->rcu_flipctr_idx = 0; | |
978 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1da177e4 LT |
979 | p->vfork_done = NULL; |
980 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
981 | |
982 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
983 | init_sigpending(&p->pending); | |
984 | ||
985 | p->utime = cputime_zero; | |
986 | p->stime = cputime_zero; | |
9ac52315 | 987 | p->gtime = cputime_zero; |
c66f08be MN |
988 | p->utimescaled = cputime_zero; |
989 | p->stimescaled = cputime_zero; | |
73a2bcb0 | 990 | p->prev_utime = cputime_zero; |
9301899b | 991 | p->prev_stime = cputime_zero; |
172ba844 | 992 | |
82a1fcb9 IM |
993 | #ifdef CONFIG_DETECT_SOFTLOCKUP |
994 | p->last_switch_count = 0; | |
995 | p->last_switch_timestamp = 0; | |
996 | #endif | |
997 | ||
5995477a | 998 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
999 | acct_clear_integrals(p); |
1000 | ||
23ff4440 | 1001 | p->it_virt_expires = cputime_zero; |
1da177e4 | 1002 | p->it_prof_expires = cputime_zero; |
23ff4440 DW |
1003 | p->it_sched_expires = 0; |
1004 | INIT_LIST_HEAD(&p->cpu_timers[0]); | |
1005 | INIT_LIST_HEAD(&p->cpu_timers[1]); | |
1006 | INIT_LIST_HEAD(&p->cpu_timers[2]); | |
1da177e4 LT |
1007 | |
1008 | p->lock_depth = -1; /* -1 = no lock */ | |
1009 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1010 | p->real_start_time = p->start_time; |
1011 | monotonic_to_bootbased(&p->real_start_time); | |
57c521ce | 1012 | #ifdef CONFIG_SECURITY |
1da177e4 | 1013 | p->security = NULL; |
57c521ce | 1014 | #endif |
3b7391de | 1015 | p->cap_bset = current->cap_bset; |
1da177e4 | 1016 | p->io_context = NULL; |
1da177e4 | 1017 | p->audit_context = NULL; |
b4f48b63 | 1018 | cgroup_fork(p); |
1da177e4 | 1019 | #ifdef CONFIG_NUMA |
846a16bf | 1020 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1021 | if (IS_ERR(p->mempolicy)) { |
1022 | retval = PTR_ERR(p->mempolicy); | |
1023 | p->mempolicy = NULL; | |
b4f48b63 | 1024 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1025 | } |
c61afb18 | 1026 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1027 | #endif |
de30a2b3 IM |
1028 | #ifdef CONFIG_TRACE_IRQFLAGS |
1029 | p->irq_events = 0; | |
b36e4758 RK |
1030 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1031 | p->hardirqs_enabled = 1; | |
1032 | #else | |
de30a2b3 | 1033 | p->hardirqs_enabled = 0; |
b36e4758 | 1034 | #endif |
de30a2b3 IM |
1035 | p->hardirq_enable_ip = 0; |
1036 | p->hardirq_enable_event = 0; | |
1037 | p->hardirq_disable_ip = _THIS_IP_; | |
1038 | p->hardirq_disable_event = 0; | |
1039 | p->softirqs_enabled = 1; | |
1040 | p->softirq_enable_ip = _THIS_IP_; | |
1041 | p->softirq_enable_event = 0; | |
1042 | p->softirq_disable_ip = 0; | |
1043 | p->softirq_disable_event = 0; | |
1044 | p->hardirq_context = 0; | |
1045 | p->softirq_context = 0; | |
1046 | #endif | |
fbb9ce95 IM |
1047 | #ifdef CONFIG_LOCKDEP |
1048 | p->lockdep_depth = 0; /* no locks held yet */ | |
1049 | p->curr_chain_key = 0; | |
1050 | p->lockdep_recursion = 0; | |
1051 | #endif | |
1da177e4 | 1052 | |
408894ee IM |
1053 | #ifdef CONFIG_DEBUG_MUTEXES |
1054 | p->blocked_on = NULL; /* not blocked yet */ | |
1055 | #endif | |
1056 | ||
3c90e6e9 SV |
1057 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1058 | sched_fork(p, clone_flags); | |
1059 | ||
1da177e4 LT |
1060 | if ((retval = security_task_alloc(p))) |
1061 | goto bad_fork_cleanup_policy; | |
1062 | if ((retval = audit_alloc(p))) | |
1063 | goto bad_fork_cleanup_security; | |
1064 | /* copy all the process information */ | |
1065 | if ((retval = copy_semundo(clone_flags, p))) | |
1066 | goto bad_fork_cleanup_audit; | |
1067 | if ((retval = copy_files(clone_flags, p))) | |
1068 | goto bad_fork_cleanup_semundo; | |
1069 | if ((retval = copy_fs(clone_flags, p))) | |
1070 | goto bad_fork_cleanup_files; | |
1071 | if ((retval = copy_sighand(clone_flags, p))) | |
1072 | goto bad_fork_cleanup_fs; | |
1073 | if ((retval = copy_signal(clone_flags, p))) | |
1074 | goto bad_fork_cleanup_sighand; | |
1075 | if ((retval = copy_mm(clone_flags, p))) | |
1076 | goto bad_fork_cleanup_signal; | |
1077 | if ((retval = copy_keys(clone_flags, p))) | |
1078 | goto bad_fork_cleanup_mm; | |
ab516013 | 1079 | if ((retval = copy_namespaces(clone_flags, p))) |
1da177e4 | 1080 | goto bad_fork_cleanup_keys; |
fadad878 | 1081 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1082 | goto bad_fork_cleanup_namespaces; |
1da177e4 LT |
1083 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); |
1084 | if (retval) | |
fd0928df | 1085 | goto bad_fork_cleanup_io; |
1da177e4 | 1086 | |
425fb2b4 PE |
1087 | if (pid != &init_struct_pid) { |
1088 | retval = -ENOMEM; | |
1089 | pid = alloc_pid(task_active_pid_ns(p)); | |
1090 | if (!pid) | |
fd0928df | 1091 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1092 | |
1093 | if (clone_flags & CLONE_NEWPID) { | |
1094 | retval = pid_ns_prepare_proc(task_active_pid_ns(p)); | |
1095 | if (retval < 0) | |
1096 | goto bad_fork_free_pid; | |
1097 | } | |
425fb2b4 PE |
1098 | } |
1099 | ||
1100 | p->pid = pid_nr(pid); | |
1101 | p->tgid = p->pid; | |
1102 | if (clone_flags & CLONE_THREAD) | |
1103 | p->tgid = current->tgid; | |
1104 | ||
e885dcde SH |
1105 | if (current->nsproxy != p->nsproxy) { |
1106 | retval = ns_cgroup_clone(p, pid); | |
1107 | if (retval) | |
1108 | goto bad_fork_free_pid; | |
1109 | } | |
1110 | ||
1da177e4 LT |
1111 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1112 | /* | |
1113 | * Clear TID on mm_release()? | |
1114 | */ | |
1115 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1116 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1117 | p->robust_list = NULL; |
1118 | #ifdef CONFIG_COMPAT | |
1119 | p->compat_robust_list = NULL; | |
1120 | #endif | |
c87e2837 IM |
1121 | INIT_LIST_HEAD(&p->pi_state_list); |
1122 | p->pi_state_cache = NULL; | |
42b2dd0a | 1123 | #endif |
f9a3879a GM |
1124 | /* |
1125 | * sigaltstack should be cleared when sharing the same VM | |
1126 | */ | |
1127 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1128 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1129 | ||
1da177e4 LT |
1130 | /* |
1131 | * Syscall tracing should be turned off in the child regardless | |
1132 | * of CLONE_PTRACE. | |
1133 | */ | |
1134 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1135 | #ifdef TIF_SYSCALL_EMU |
1136 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1137 | #endif | |
9745512c | 1138 | clear_all_latency_tracing(p); |
1da177e4 LT |
1139 | |
1140 | /* Our parent execution domain becomes current domain | |
1141 | These must match for thread signalling to apply */ | |
1da177e4 LT |
1142 | p->parent_exec_id = p->self_exec_id; |
1143 | ||
1144 | /* ok, now we should be set up.. */ | |
1145 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1146 | p->pdeath_signal = 0; | |
1147 | p->exit_state = 0; | |
1148 | ||
1da177e4 LT |
1149 | /* |
1150 | * Ok, make it visible to the rest of the system. | |
1151 | * We dont wake it up yet. | |
1152 | */ | |
1153 | p->group_leader = p; | |
47e65328 | 1154 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 | 1155 | |
b4f48b63 PM |
1156 | /* Now that the task is set up, run cgroup callbacks if |
1157 | * necessary. We need to run them before the task is visible | |
1158 | * on the tasklist. */ | |
1159 | cgroup_fork_callbacks(p); | |
1160 | cgroup_callbacks_done = 1; | |
1161 | ||
1da177e4 LT |
1162 | /* Need tasklist lock for parent etc handling! */ |
1163 | write_lock_irq(&tasklist_lock); | |
1164 | ||
1165 | /* | |
476d139c NP |
1166 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1167 | * not be changed, nor will its assigned CPU. | |
1168 | * | |
1169 | * The cpus_allowed mask of the parent may have changed after it was | |
1170 | * copied first time - so re-copy it here, then check the child's CPU | |
1171 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1172 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1173 | */ |
1174 | p->cpus_allowed = current->cpus_allowed; | |
6f505b16 | 1175 | p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed; |
26ff6ad9 SV |
1176 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1177 | !cpu_online(task_cpu(p)))) | |
476d139c | 1178 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1179 | |
1da177e4 LT |
1180 | /* CLONE_PARENT re-uses the old parent */ |
1181 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) | |
1182 | p->real_parent = current->real_parent; | |
1183 | else | |
1184 | p->real_parent = current; | |
1da177e4 | 1185 | |
3f17da69 | 1186 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1187 | |
1188 | /* | |
1189 | * Process group and session signals need to be delivered to just the | |
1190 | * parent before the fork or both the parent and the child after the | |
1191 | * fork. Restart if a signal comes in before we add the new process to | |
1192 | * it's process group. | |
1193 | * A fatal signal pending means that current will exit, so the new | |
1194 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1195 | */ | |
23ff4440 | 1196 | recalc_sigpending(); |
4a2c7a78 ON |
1197 | if (signal_pending(current)) { |
1198 | spin_unlock(¤t->sighand->siglock); | |
1199 | write_unlock_irq(&tasklist_lock); | |
1200 | retval = -ERESTARTNOINTR; | |
425fb2b4 | 1201 | goto bad_fork_free_pid; |
4a2c7a78 ON |
1202 | } |
1203 | ||
1da177e4 | 1204 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1205 | p->group_leader = current->group_leader; |
47e65328 | 1206 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 | 1207 | |
1da177e4 LT |
1208 | if (!cputime_eq(current->signal->it_virt_expires, |
1209 | cputime_zero) || | |
1210 | !cputime_eq(current->signal->it_prof_expires, | |
1211 | cputime_zero) || | |
1212 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || | |
1213 | !list_empty(¤t->signal->cpu_timers[0]) || | |
1214 | !list_empty(¤t->signal->cpu_timers[1]) || | |
1215 | !list_empty(¤t->signal->cpu_timers[2])) { | |
1216 | /* | |
1217 | * Have child wake up on its first tick to check | |
1218 | * for process CPU timers. | |
1219 | */ | |
1220 | p->it_prof_expires = jiffies_to_cputime(1); | |
1221 | } | |
1da177e4 LT |
1222 | } |
1223 | ||
73b9ebfe | 1224 | if (likely(p->pid)) { |
f470021a | 1225 | list_add_tail(&p->sibling, &p->real_parent->children); |
09a05394 | 1226 | tracehook_finish_clone(p, clone_flags, trace); |
73b9ebfe ON |
1227 | |
1228 | if (thread_group_leader(p)) { | |
5cd17569 | 1229 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1230 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1231 | |
fea9d175 | 1232 | p->signal->leader_pid = pid; |
9c9f4ded AC |
1233 | tty_kref_put(p->signal->tty); |
1234 | p->signal->tty = tty_kref_get(current->signal->tty); | |
5cd17569 EB |
1235 | set_task_pgrp(p, task_pgrp_nr(current)); |
1236 | set_task_session(p, task_session_nr(current)); | |
1237 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); | |
1238 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
5e85d4ab | 1239 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1240 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1241 | } |
85868995 | 1242 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1243 | nr_threads++; |
1da177e4 LT |
1244 | } |
1245 | ||
1da177e4 | 1246 | total_forks++; |
3f17da69 | 1247 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1248 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1249 | proc_fork_connector(p); |
817929ec | 1250 | cgroup_post_fork(p); |
1da177e4 LT |
1251 | return p; |
1252 | ||
425fb2b4 PE |
1253 | bad_fork_free_pid: |
1254 | if (pid != &init_struct_pid) | |
1255 | free_pid(pid); | |
fd0928df JA |
1256 | bad_fork_cleanup_io: |
1257 | put_io_context(p->io_context); | |
ab516013 | 1258 | bad_fork_cleanup_namespaces: |
444f378b | 1259 | exit_task_namespaces(p); |
1da177e4 LT |
1260 | bad_fork_cleanup_keys: |
1261 | exit_keys(p); | |
1262 | bad_fork_cleanup_mm: | |
1263 | if (p->mm) | |
1264 | mmput(p->mm); | |
1265 | bad_fork_cleanup_signal: | |
6b3934ef | 1266 | cleanup_signal(p); |
1da177e4 | 1267 | bad_fork_cleanup_sighand: |
a7e5328a | 1268 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1269 | bad_fork_cleanup_fs: |
1270 | exit_fs(p); /* blocking */ | |
1271 | bad_fork_cleanup_files: | |
1272 | exit_files(p); /* blocking */ | |
1273 | bad_fork_cleanup_semundo: | |
1274 | exit_sem(p); | |
1275 | bad_fork_cleanup_audit: | |
1276 | audit_free(p); | |
1277 | bad_fork_cleanup_security: | |
1278 | security_task_free(p); | |
1279 | bad_fork_cleanup_policy: | |
1280 | #ifdef CONFIG_NUMA | |
f0be3d32 | 1281 | mpol_put(p->mempolicy); |
b4f48b63 | 1282 | bad_fork_cleanup_cgroup: |
1da177e4 | 1283 | #endif |
b4f48b63 | 1284 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1285 | delayacct_tsk_free(p); |
1da177e4 LT |
1286 | if (p->binfmt) |
1287 | module_put(p->binfmt->module); | |
1288 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1289 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 LT |
1290 | bad_fork_cleanup_count: |
1291 | put_group_info(p->group_info); | |
1292 | atomic_dec(&p->user->processes); | |
1293 | free_uid(p->user); | |
1294 | bad_fork_free: | |
1295 | free_task(p); | |
fe7d37d1 ON |
1296 | fork_out: |
1297 | return ERR_PTR(retval); | |
1da177e4 LT |
1298 | } |
1299 | ||
6b2fb3c6 | 1300 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1301 | { |
1302 | memset(regs, 0, sizeof(struct pt_regs)); | |
1303 | return regs; | |
1304 | } | |
1305 | ||
9abcf40b | 1306 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1307 | { |
36c8b586 | 1308 | struct task_struct *task; |
1da177e4 LT |
1309 | struct pt_regs regs; |
1310 | ||
30e49c26 | 1311 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
09a05394 | 1312 | &init_struct_pid, 0); |
753ca4f3 AM |
1313 | if (!IS_ERR(task)) |
1314 | init_idle(task, cpu); | |
73b9ebfe | 1315 | |
1da177e4 LT |
1316 | return task; |
1317 | } | |
1318 | ||
1da177e4 LT |
1319 | /* |
1320 | * Ok, this is the main fork-routine. | |
1321 | * | |
1322 | * It copies the process, and if successful kick-starts | |
1323 | * it and waits for it to finish using the VM if required. | |
1324 | */ | |
1325 | long do_fork(unsigned long clone_flags, | |
1326 | unsigned long stack_start, | |
1327 | struct pt_regs *regs, | |
1328 | unsigned long stack_size, | |
1329 | int __user *parent_tidptr, | |
1330 | int __user *child_tidptr) | |
1331 | { | |
1332 | struct task_struct *p; | |
1333 | int trace = 0; | |
92476d7f | 1334 | long nr; |
1da177e4 | 1335 | |
bdff746a AM |
1336 | /* |
1337 | * We hope to recycle these flags after 2.6.26 | |
1338 | */ | |
1339 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1340 | static int __read_mostly count = 100; | |
1341 | ||
1342 | if (count > 0 && printk_ratelimit()) { | |
1343 | char comm[TASK_COMM_LEN]; | |
1344 | ||
1345 | count--; | |
1346 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1347 | "clone flags 0x%lx\n", | |
1348 | get_task_comm(comm, current), | |
1349 | clone_flags & CLONE_STOPPED); | |
1350 | } | |
1351 | } | |
1352 | ||
09a05394 RM |
1353 | /* |
1354 | * When called from kernel_thread, don't do user tracing stuff. | |
1355 | */ | |
1356 | if (likely(user_mode(regs))) | |
1357 | trace = tracehook_prepare_clone(clone_flags); | |
1da177e4 | 1358 | |
a6f5e063 | 1359 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
09a05394 | 1360 | child_tidptr, NULL, trace); |
1da177e4 LT |
1361 | /* |
1362 | * Do this prior waking up the new thread - the thread pointer | |
1363 | * might get invalid after that point, if the thread exits quickly. | |
1364 | */ | |
1365 | if (!IS_ERR(p)) { | |
1366 | struct completion vfork; | |
1367 | ||
0a16b607 MD |
1368 | trace_sched_process_fork(current, p); |
1369 | ||
6c5f3e7b | 1370 | nr = task_pid_vnr(p); |
30e49c26 PE |
1371 | |
1372 | if (clone_flags & CLONE_PARENT_SETTID) | |
1373 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1374 | |
1da177e4 LT |
1375 | if (clone_flags & CLONE_VFORK) { |
1376 | p->vfork_done = &vfork; | |
1377 | init_completion(&vfork); | |
1378 | } | |
1379 | ||
09a05394 RM |
1380 | tracehook_report_clone(trace, regs, clone_flags, nr, p); |
1381 | ||
1382 | /* | |
1383 | * We set PF_STARTING at creation in case tracing wants to | |
1384 | * use this to distinguish a fully live task from one that | |
1385 | * hasn't gotten to tracehook_report_clone() yet. Now we | |
1386 | * clear it and set the child going. | |
1387 | */ | |
1388 | p->flags &= ~PF_STARTING; | |
1389 | ||
1390 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1da177e4 LT |
1391 | /* |
1392 | * We'll start up with an immediate SIGSTOP. | |
1393 | */ | |
1394 | sigaddset(&p->pending.signal, SIGSTOP); | |
1395 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
d9ae90ac | 1396 | __set_task_state(p, TASK_STOPPED); |
09a05394 RM |
1397 | } else { |
1398 | wake_up_new_task(p, clone_flags); | |
1da177e4 LT |
1399 | } |
1400 | ||
09a05394 RM |
1401 | tracehook_report_clone_complete(trace, regs, |
1402 | clone_flags, nr, p); | |
1403 | ||
1da177e4 | 1404 | if (clone_flags & CLONE_VFORK) { |
ba96a0c8 | 1405 | freezer_do_not_count(); |
1da177e4 | 1406 | wait_for_completion(&vfork); |
ba96a0c8 | 1407 | freezer_count(); |
daded34b | 1408 | tracehook_report_vfork_done(p, nr); |
1da177e4 LT |
1409 | } |
1410 | } else { | |
92476d7f | 1411 | nr = PTR_ERR(p); |
1da177e4 | 1412 | } |
92476d7f | 1413 | return nr; |
1da177e4 LT |
1414 | } |
1415 | ||
5fd63b30 RT |
1416 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1417 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1418 | #endif | |
1419 | ||
51cc5068 | 1420 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1421 | { |
1422 | struct sighand_struct *sighand = data; | |
1423 | ||
a35afb83 | 1424 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1425 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1426 | } |
1427 | ||
1da177e4 LT |
1428 | void __init proc_caches_init(void) |
1429 | { | |
1430 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1431 | sizeof(struct sighand_struct), 0, | |
aa1757f9 | 1432 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
20c2df83 | 1433 | sighand_ctor); |
1da177e4 LT |
1434 | signal_cachep = kmem_cache_create("signal_cache", |
1435 | sizeof(struct signal_struct), 0, | |
20c2df83 PM |
1436 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1437 | files_cachep = kmem_cache_create("files_cache", | |
1da177e4 | 1438 | sizeof(struct files_struct), 0, |
20c2df83 PM |
1439 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1440 | fs_cachep = kmem_cache_create("fs_cache", | |
1da177e4 | 1441 | sizeof(struct fs_struct), 0, |
20c2df83 | 1442 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 LT |
1443 | vm_area_cachep = kmem_cache_create("vm_area_struct", |
1444 | sizeof(struct vm_area_struct), 0, | |
20c2df83 | 1445 | SLAB_PANIC, NULL); |
1da177e4 | 1446 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1447 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
20c2df83 | 1448 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 1449 | } |
cf2e340f | 1450 | |
cf2e340f JD |
1451 | /* |
1452 | * Check constraints on flags passed to the unshare system call and | |
1453 | * force unsharing of additional process context as appropriate. | |
1454 | */ | |
a39bc516 | 1455 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1456 | { |
1457 | /* | |
1458 | * If unsharing a thread from a thread group, must also | |
1459 | * unshare vm. | |
1460 | */ | |
1461 | if (*flags_ptr & CLONE_THREAD) | |
1462 | *flags_ptr |= CLONE_VM; | |
1463 | ||
1464 | /* | |
1465 | * If unsharing vm, must also unshare signal handlers. | |
1466 | */ | |
1467 | if (*flags_ptr & CLONE_VM) | |
1468 | *flags_ptr |= CLONE_SIGHAND; | |
1469 | ||
1470 | /* | |
1471 | * If unsharing signal handlers and the task was created | |
1472 | * using CLONE_THREAD, then must unshare the thread | |
1473 | */ | |
1474 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1475 | (atomic_read(¤t->signal->count) > 1)) | |
1476 | *flags_ptr |= CLONE_THREAD; | |
1477 | ||
1478 | /* | |
1479 | * If unsharing namespace, must also unshare filesystem information. | |
1480 | */ | |
1481 | if (*flags_ptr & CLONE_NEWNS) | |
1482 | *flags_ptr |= CLONE_FS; | |
1483 | } | |
1484 | ||
1485 | /* | |
1486 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1487 | */ | |
1488 | static int unshare_thread(unsigned long unshare_flags) | |
1489 | { | |
1490 | if (unshare_flags & CLONE_THREAD) | |
1491 | return -EINVAL; | |
1492 | ||
1493 | return 0; | |
1494 | } | |
1495 | ||
1496 | /* | |
99d1419d | 1497 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1498 | */ |
1499 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1500 | { | |
1501 | struct fs_struct *fs = current->fs; | |
1502 | ||
1503 | if ((unshare_flags & CLONE_FS) && | |
99d1419d JD |
1504 | (fs && atomic_read(&fs->count) > 1)) { |
1505 | *new_fsp = __copy_fs_struct(current->fs); | |
1506 | if (!*new_fsp) | |
1507 | return -ENOMEM; | |
1508 | } | |
cf2e340f JD |
1509 | |
1510 | return 0; | |
1511 | } | |
1512 | ||
cf2e340f | 1513 | /* |
dae3c5a0 | 1514 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1515 | */ |
1516 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1517 | { | |
1518 | struct sighand_struct *sigh = current->sighand; | |
1519 | ||
dae3c5a0 | 1520 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1521 | return -EINVAL; |
1522 | else | |
1523 | return 0; | |
1524 | } | |
1525 | ||
1526 | /* | |
a0a7ec30 | 1527 | * Unshare vm if it is being shared |
cf2e340f JD |
1528 | */ |
1529 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1530 | { | |
1531 | struct mm_struct *mm = current->mm; | |
1532 | ||
1533 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1534 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1535 | return -EINVAL; |
a0a7ec30 | 1536 | } |
cf2e340f JD |
1537 | |
1538 | return 0; | |
cf2e340f JD |
1539 | } |
1540 | ||
1541 | /* | |
a016f338 | 1542 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1543 | */ |
1544 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1545 | { | |
1546 | struct files_struct *fd = current->files; | |
a016f338 | 1547 | int error = 0; |
cf2e340f JD |
1548 | |
1549 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1550 | (fd && atomic_read(&fd->count) > 1)) { |
1551 | *new_fdp = dup_fd(fd, &error); | |
1552 | if (!*new_fdp) | |
1553 | return error; | |
1554 | } | |
cf2e340f JD |
1555 | |
1556 | return 0; | |
1557 | } | |
1558 | ||
cf2e340f JD |
1559 | /* |
1560 | * unshare allows a process to 'unshare' part of the process | |
1561 | * context which was originally shared using clone. copy_* | |
1562 | * functions used by do_fork() cannot be used here directly | |
1563 | * because they modify an inactive task_struct that is being | |
1564 | * constructed. Here we are modifying the current, active, | |
1565 | * task_struct. | |
1566 | */ | |
1567 | asmlinkage long sys_unshare(unsigned long unshare_flags) | |
1568 | { | |
1569 | int err = 0; | |
1570 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1571 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1572 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1573 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1574 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1575 | int do_sysvsem = 0; |
cf2e340f JD |
1576 | |
1577 | check_unshare_flags(&unshare_flags); | |
1578 | ||
06f9d4f9 EB |
1579 | /* Return -EINVAL for all unsupported flags */ |
1580 | err = -EINVAL; | |
1581 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1582 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
9dd776b6 EB |
1583 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER| |
1584 | CLONE_NEWNET)) | |
06f9d4f9 EB |
1585 | goto bad_unshare_out; |
1586 | ||
6013f67f MS |
1587 | /* |
1588 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1589 | * to a new ipc namespace, the semaphore arrays from the old | |
1590 | * namespace are unreachable. | |
1591 | */ | |
1592 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1593 | do_sysvsem = 1; |
cf2e340f JD |
1594 | if ((err = unshare_thread(unshare_flags))) |
1595 | goto bad_unshare_out; | |
1596 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1597 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1598 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1599 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1600 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1601 | goto bad_unshare_cleanup_sigh; | |
1602 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1603 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1604 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1605 | new_fs))) | |
9edff4ab | 1606 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1607 | |
9edff4ab MS |
1608 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1609 | if (do_sysvsem) { | |
1610 | /* | |
1611 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1612 | */ | |
1613 | exit_sem(current); | |
1614 | } | |
ab516013 | 1615 | |
c0b2fc31 | 1616 | if (new_nsproxy) { |
cf7b708c PE |
1617 | switch_task_namespaces(current, new_nsproxy); |
1618 | new_nsproxy = NULL; | |
c0b2fc31 | 1619 | } |
cf2e340f | 1620 | |
cf7b708c PE |
1621 | task_lock(current); |
1622 | ||
cf2e340f JD |
1623 | if (new_fs) { |
1624 | fs = current->fs; | |
1625 | current->fs = new_fs; | |
1626 | new_fs = fs; | |
1627 | } | |
1628 | ||
cf2e340f JD |
1629 | if (new_mm) { |
1630 | mm = current->mm; | |
1631 | active_mm = current->active_mm; | |
1632 | current->mm = new_mm; | |
1633 | current->active_mm = new_mm; | |
1634 | activate_mm(active_mm, new_mm); | |
1635 | new_mm = mm; | |
1636 | } | |
1637 | ||
1638 | if (new_fd) { | |
1639 | fd = current->files; | |
1640 | current->files = new_fd; | |
1641 | new_fd = fd; | |
1642 | } | |
1643 | ||
1644 | task_unlock(current); | |
1645 | } | |
1646 | ||
c0b2fc31 | 1647 | if (new_nsproxy) |
444f378b | 1648 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1649 | |
cf2e340f JD |
1650 | bad_unshare_cleanup_fd: |
1651 | if (new_fd) | |
1652 | put_files_struct(new_fd); | |
1653 | ||
1654 | bad_unshare_cleanup_vm: | |
1655 | if (new_mm) | |
1656 | mmput(new_mm); | |
1657 | ||
1658 | bad_unshare_cleanup_sigh: | |
1659 | if (new_sigh) | |
1660 | if (atomic_dec_and_test(&new_sigh->count)) | |
1661 | kmem_cache_free(sighand_cachep, new_sigh); | |
1662 | ||
cf2e340f JD |
1663 | bad_unshare_cleanup_fs: |
1664 | if (new_fs) | |
1665 | put_fs_struct(new_fs); | |
1666 | ||
1667 | bad_unshare_cleanup_thread: | |
1668 | bad_unshare_out: | |
1669 | return err; | |
1670 | } | |
3b125388 AV |
1671 | |
1672 | /* | |
1673 | * Helper to unshare the files of the current task. | |
1674 | * We don't want to expose copy_files internals to | |
1675 | * the exec layer of the kernel. | |
1676 | */ | |
1677 | ||
1678 | int unshare_files(struct files_struct **displaced) | |
1679 | { | |
1680 | struct task_struct *task = current; | |
50704516 | 1681 | struct files_struct *copy = NULL; |
3b125388 AV |
1682 | int error; |
1683 | ||
1684 | error = unshare_fd(CLONE_FILES, ©); | |
1685 | if (error || !copy) { | |
1686 | *displaced = NULL; | |
1687 | return error; | |
1688 | } | |
1689 | *displaced = task->files; | |
1690 | task_lock(task); | |
1691 | task->files = copy; | |
1692 | task_unlock(task); | |
1693 | return 0; | |
1694 | } |