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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/fork.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'fork.c' contains the help-routines for the 'fork' system call | |
9 | * (see also entry.S and others). | |
10 | * Fork is rather simple, once you get the hang of it, but the memory | |
11 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' | |
12 | */ | |
13 | ||
1da177e4 LT |
14 | #include <linux/slab.h> |
15 | #include <linux/init.h> | |
16 | #include <linux/unistd.h> | |
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/completion.h> | |
6b3286ed | 20 | #include <linux/mnt_namespace.h> |
1da177e4 LT |
21 | #include <linux/personality.h> |
22 | #include <linux/mempolicy.h> | |
23 | #include <linux/sem.h> | |
24 | #include <linux/file.h> | |
9f3acc31 | 25 | #include <linux/fdtable.h> |
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> |
8141c7f3 | 43 | #include <linux/compat.h> |
7c3ab738 | 44 | #include <linux/task_io_accounting_ops.h> |
ab2af1f5 | 45 | #include <linux/rcupdate.h> |
1da177e4 LT |
46 | #include <linux/ptrace.h> |
47 | #include <linux/mount.h> | |
48 | #include <linux/audit.h> | |
78fb7466 | 49 | #include <linux/memcontrol.h> |
f201ae23 | 50 | #include <linux/ftrace.h> |
1da177e4 LT |
51 | #include <linux/profile.h> |
52 | #include <linux/rmap.h> | |
53 | #include <linux/acct.h> | |
8f0ab514 | 54 | #include <linux/tsacct_kern.h> |
9f46080c | 55 | #include <linux/cn_proc.h> |
ba96a0c8 | 56 | #include <linux/freezer.h> |
ca74e92b | 57 | #include <linux/delayacct.h> |
ad4ecbcb | 58 | #include <linux/taskstats_kern.h> |
0a425405 | 59 | #include <linux/random.h> |
522ed776 | 60 | #include <linux/tty.h> |
6f4e6433 | 61 | #include <linux/proc_fs.h> |
fd0928df | 62 | #include <linux/blkdev.h> |
5ad4e53b | 63 | #include <linux/fs_struct.h> |
0a16b607 | 64 | #include <trace/sched.h> |
7c9f8861 | 65 | #include <linux/magic.h> |
1da177e4 LT |
66 | |
67 | #include <asm/pgtable.h> | |
68 | #include <asm/pgalloc.h> | |
69 | #include <asm/uaccess.h> | |
70 | #include <asm/mmu_context.h> | |
71 | #include <asm/cacheflush.h> | |
72 | #include <asm/tlbflush.h> | |
73 | ||
74 | /* | |
75 | * Protected counters by write_lock_irq(&tasklist_lock) | |
76 | */ | |
77 | unsigned long total_forks; /* Handle normal Linux uptimes. */ | |
78 | int nr_threads; /* The idle threads do not count.. */ | |
79 | ||
80 | int max_threads; /* tunable limit on nr_threads */ | |
81 | ||
82 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; | |
83 | ||
c59923a1 | 84 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
1da177e4 | 85 | |
7e066fb8 MD |
86 | DEFINE_TRACE(sched_process_fork); |
87 | ||
1da177e4 LT |
88 | int nr_processes(void) |
89 | { | |
90 | int cpu; | |
91 | int total = 0; | |
92 | ||
93 | for_each_online_cpu(cpu) | |
94 | total += per_cpu(process_counts, cpu); | |
95 | ||
96 | return total; | |
97 | } | |
98 | ||
99 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
100 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) | |
101 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) | |
e18b890b | 102 | static struct kmem_cache *task_struct_cachep; |
1da177e4 LT |
103 | #endif |
104 | ||
b69c49b7 FT |
105 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
106 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) | |
107 | { | |
108 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
109 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; | |
110 | #else | |
111 | gfp_t mask = GFP_KERNEL; | |
112 | #endif | |
113 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); | |
114 | } | |
115 | ||
116 | static inline void free_thread_info(struct thread_info *ti) | |
117 | { | |
118 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); | |
119 | } | |
120 | #endif | |
121 | ||
1da177e4 | 122 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
e18b890b | 123 | static struct kmem_cache *signal_cachep; |
1da177e4 LT |
124 | |
125 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ | |
e18b890b | 126 | struct kmem_cache *sighand_cachep; |
1da177e4 LT |
127 | |
128 | /* SLAB cache for files_struct structures (tsk->files) */ | |
e18b890b | 129 | struct kmem_cache *files_cachep; |
1da177e4 LT |
130 | |
131 | /* SLAB cache for fs_struct structures (tsk->fs) */ | |
e18b890b | 132 | struct kmem_cache *fs_cachep; |
1da177e4 LT |
133 | |
134 | /* SLAB cache for vm_area_struct structures */ | |
e18b890b | 135 | struct kmem_cache *vm_area_cachep; |
1da177e4 LT |
136 | |
137 | /* SLAB cache for mm_struct structures (tsk->mm) */ | |
e18b890b | 138 | static struct kmem_cache *mm_cachep; |
1da177e4 LT |
139 | |
140 | void free_task(struct task_struct *tsk) | |
141 | { | |
3e26c149 | 142 | prop_local_destroy_single(&tsk->dirties); |
f7e4217b | 143 | free_thread_info(tsk->stack); |
23f78d4a | 144 | rt_mutex_debug_task_free(tsk); |
fb52607a | 145 | ftrace_graph_exit_task(tsk); |
1da177e4 LT |
146 | free_task_struct(tsk); |
147 | } | |
148 | EXPORT_SYMBOL(free_task); | |
149 | ||
158d9ebd | 150 | void __put_task_struct(struct task_struct *tsk) |
1da177e4 | 151 | { |
270f722d | 152 | WARN_ON(!tsk->exit_state); |
1da177e4 LT |
153 | WARN_ON(atomic_read(&tsk->usage)); |
154 | WARN_ON(tsk == current); | |
155 | ||
3b11a1de | 156 | put_cred(tsk->real_cred); |
f1752eec | 157 | put_cred(tsk->cred); |
35df17c5 | 158 | delayacct_tsk_free(tsk); |
1da177e4 LT |
159 | |
160 | if (!profile_handoff_task(tsk)) | |
161 | free_task(tsk); | |
162 | } | |
163 | ||
2adee9b3 SS |
164 | /* |
165 | * macro override instead of weak attribute alias, to workaround | |
166 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. | |
167 | */ | |
168 | #ifndef arch_task_cache_init | |
169 | #define arch_task_cache_init() | |
170 | #endif | |
61c4628b | 171 | |
1da177e4 LT |
172 | void __init fork_init(unsigned long mempages) |
173 | { | |
174 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR | |
175 | #ifndef ARCH_MIN_TASKALIGN | |
176 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES | |
177 | #endif | |
178 | /* create a slab on which task_structs can be allocated */ | |
179 | task_struct_cachep = | |
180 | kmem_cache_create("task_struct", sizeof(struct task_struct), | |
20c2df83 | 181 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL); |
1da177e4 LT |
182 | #endif |
183 | ||
61c4628b SS |
184 | /* do the arch specific task caches init */ |
185 | arch_task_cache_init(); | |
186 | ||
1da177e4 LT |
187 | /* |
188 | * The default maximum number of threads is set to a safe | |
189 | * value: the thread structures can take up at most half | |
190 | * of memory. | |
191 | */ | |
192 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); | |
193 | ||
194 | /* | |
195 | * we need to allow at least 20 threads to boot a system | |
196 | */ | |
197 | if(max_threads < 20) | |
198 | max_threads = 20; | |
199 | ||
200 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; | |
201 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; | |
202 | init_task.signal->rlim[RLIMIT_SIGPENDING] = | |
203 | init_task.signal->rlim[RLIMIT_NPROC]; | |
204 | } | |
205 | ||
61c4628b SS |
206 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
207 | struct task_struct *src) | |
208 | { | |
209 | *dst = *src; | |
210 | return 0; | |
211 | } | |
212 | ||
1da177e4 LT |
213 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
214 | { | |
215 | struct task_struct *tsk; | |
216 | struct thread_info *ti; | |
7c9f8861 ES |
217 | unsigned long *stackend; |
218 | ||
3e26c149 | 219 | int err; |
1da177e4 LT |
220 | |
221 | prepare_to_copy(orig); | |
222 | ||
223 | tsk = alloc_task_struct(); | |
224 | if (!tsk) | |
225 | return NULL; | |
226 | ||
227 | ti = alloc_thread_info(tsk); | |
228 | if (!ti) { | |
229 | free_task_struct(tsk); | |
230 | return NULL; | |
231 | } | |
232 | ||
61c4628b SS |
233 | err = arch_dup_task_struct(tsk, orig); |
234 | if (err) | |
235 | goto out; | |
236 | ||
f7e4217b | 237 | tsk->stack = ti; |
3e26c149 PZ |
238 | |
239 | err = prop_local_init_single(&tsk->dirties); | |
61c4628b SS |
240 | if (err) |
241 | goto out; | |
3e26c149 | 242 | |
10ebffde | 243 | setup_thread_stack(tsk, orig); |
7c9f8861 ES |
244 | stackend = end_of_stack(tsk); |
245 | *stackend = STACK_END_MAGIC; /* for overflow detection */ | |
1da177e4 | 246 | |
0a425405 AV |
247 | #ifdef CONFIG_CC_STACKPROTECTOR |
248 | tsk->stack_canary = get_random_int(); | |
249 | #endif | |
250 | ||
1da177e4 LT |
251 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
252 | atomic_set(&tsk->usage,2); | |
4b5d37ac | 253 | atomic_set(&tsk->fs_excl, 0); |
6c5c9341 | 254 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
2056a782 | 255 | tsk->btrace_seq = 0; |
6c5c9341 | 256 | #endif |
a0aa7f68 | 257 | tsk->splice_pipe = NULL; |
1da177e4 | 258 | return tsk; |
61c4628b SS |
259 | |
260 | out: | |
261 | free_thread_info(ti); | |
262 | free_task_struct(tsk); | |
263 | return NULL; | |
1da177e4 LT |
264 | } |
265 | ||
266 | #ifdef CONFIG_MMU | |
a39bc516 | 267 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
1da177e4 | 268 | { |
fd3e42fc | 269 | struct vm_area_struct *mpnt, *tmp, **pprev; |
1da177e4 LT |
270 | struct rb_node **rb_link, *rb_parent; |
271 | int retval; | |
272 | unsigned long charge; | |
273 | struct mempolicy *pol; | |
274 | ||
275 | down_write(&oldmm->mmap_sem); | |
ec8c0446 | 276 | flush_cache_dup_mm(oldmm); |
ad339451 IM |
277 | /* |
278 | * Not linked in yet - no deadlock potential: | |
279 | */ | |
280 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); | |
7ee78232 | 281 | |
1da177e4 LT |
282 | mm->locked_vm = 0; |
283 | mm->mmap = NULL; | |
284 | mm->mmap_cache = NULL; | |
285 | mm->free_area_cache = oldmm->mmap_base; | |
1363c3cd | 286 | mm->cached_hole_size = ~0UL; |
1da177e4 | 287 | mm->map_count = 0; |
94894244 | 288 | cpumask_clear(mm_cpumask(mm)); |
1da177e4 LT |
289 | mm->mm_rb = RB_ROOT; |
290 | rb_link = &mm->mm_rb.rb_node; | |
291 | rb_parent = NULL; | |
292 | pprev = &mm->mmap; | |
293 | ||
fd3e42fc | 294 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
1da177e4 LT |
295 | struct file *file; |
296 | ||
297 | if (mpnt->vm_flags & VM_DONTCOPY) { | |
3b6bfcdb HD |
298 | long pages = vma_pages(mpnt); |
299 | mm->total_vm -= pages; | |
ab50b8ed | 300 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
3b6bfcdb | 301 | -pages); |
1da177e4 LT |
302 | continue; |
303 | } | |
304 | charge = 0; | |
305 | if (mpnt->vm_flags & VM_ACCOUNT) { | |
306 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; | |
307 | if (security_vm_enough_memory(len)) | |
308 | goto fail_nomem; | |
309 | charge = len; | |
310 | } | |
e94b1766 | 311 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
312 | if (!tmp) |
313 | goto fail_nomem; | |
314 | *tmp = *mpnt; | |
846a16bf | 315 | pol = mpol_dup(vma_policy(mpnt)); |
1da177e4 LT |
316 | retval = PTR_ERR(pol); |
317 | if (IS_ERR(pol)) | |
318 | goto fail_nomem_policy; | |
319 | vma_set_policy(tmp, pol); | |
320 | tmp->vm_flags &= ~VM_LOCKED; | |
321 | tmp->vm_mm = mm; | |
322 | tmp->vm_next = NULL; | |
323 | anon_vma_link(tmp); | |
324 | file = tmp->vm_file; | |
325 | if (file) { | |
f3a43f3f | 326 | struct inode *inode = file->f_path.dentry->d_inode; |
b88ed205 HD |
327 | struct address_space *mapping = file->f_mapping; |
328 | ||
1da177e4 LT |
329 | get_file(file); |
330 | if (tmp->vm_flags & VM_DENYWRITE) | |
331 | atomic_dec(&inode->i_writecount); | |
b88ed205 HD |
332 | spin_lock(&mapping->i_mmap_lock); |
333 | if (tmp->vm_flags & VM_SHARED) | |
334 | mapping->i_mmap_writable++; | |
1da177e4 | 335 | tmp->vm_truncate_count = mpnt->vm_truncate_count; |
b88ed205 HD |
336 | flush_dcache_mmap_lock(mapping); |
337 | /* insert tmp into the share list, just after mpnt */ | |
1da177e4 | 338 | vma_prio_tree_add(tmp, mpnt); |
b88ed205 HD |
339 | flush_dcache_mmap_unlock(mapping); |
340 | spin_unlock(&mapping->i_mmap_lock); | |
1da177e4 LT |
341 | } |
342 | ||
a1e78772 MG |
343 | /* |
344 | * Clear hugetlb-related page reserves for children. This only | |
345 | * affects MAP_PRIVATE mappings. Faults generated by the child | |
346 | * are not guaranteed to succeed, even if read-only | |
347 | */ | |
348 | if (is_vm_hugetlb_page(tmp)) | |
349 | reset_vma_resv_huge_pages(tmp); | |
350 | ||
1da177e4 | 351 | /* |
7ee78232 | 352 | * Link in the new vma and copy the page table entries. |
1da177e4 | 353 | */ |
1da177e4 LT |
354 | *pprev = tmp; |
355 | pprev = &tmp->vm_next; | |
356 | ||
357 | __vma_link_rb(mm, tmp, rb_link, rb_parent); | |
358 | rb_link = &tmp->vm_rb.rb_right; | |
359 | rb_parent = &tmp->vm_rb; | |
360 | ||
361 | mm->map_count++; | |
0b0db14c | 362 | retval = copy_page_range(mm, oldmm, mpnt); |
1da177e4 LT |
363 | |
364 | if (tmp->vm_ops && tmp->vm_ops->open) | |
365 | tmp->vm_ops->open(tmp); | |
366 | ||
367 | if (retval) | |
368 | goto out; | |
369 | } | |
d6dd61c8 JF |
370 | /* a new mm has just been created */ |
371 | arch_dup_mmap(oldmm, mm); | |
1da177e4 | 372 | retval = 0; |
1da177e4 | 373 | out: |
7ee78232 | 374 | up_write(&mm->mmap_sem); |
fd3e42fc | 375 | flush_tlb_mm(oldmm); |
1da177e4 LT |
376 | up_write(&oldmm->mmap_sem); |
377 | return retval; | |
378 | fail_nomem_policy: | |
379 | kmem_cache_free(vm_area_cachep, tmp); | |
380 | fail_nomem: | |
381 | retval = -ENOMEM; | |
382 | vm_unacct_memory(charge); | |
383 | goto out; | |
384 | } | |
385 | ||
386 | static inline int mm_alloc_pgd(struct mm_struct * mm) | |
387 | { | |
388 | mm->pgd = pgd_alloc(mm); | |
389 | if (unlikely(!mm->pgd)) | |
390 | return -ENOMEM; | |
391 | return 0; | |
392 | } | |
393 | ||
394 | static inline void mm_free_pgd(struct mm_struct * mm) | |
395 | { | |
5e541973 | 396 | pgd_free(mm, mm->pgd); |
1da177e4 LT |
397 | } |
398 | #else | |
399 | #define dup_mmap(mm, oldmm) (0) | |
400 | #define mm_alloc_pgd(mm) (0) | |
401 | #define mm_free_pgd(mm) | |
402 | #endif /* CONFIG_MMU */ | |
403 | ||
23ff4440 | 404 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
1da177e4 | 405 | |
e94b1766 | 406 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
1da177e4 LT |
407 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
408 | ||
4cb0e11b HK |
409 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
410 | ||
411 | static int __init coredump_filter_setup(char *s) | |
412 | { | |
413 | default_dump_filter = | |
414 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & | |
415 | MMF_DUMP_FILTER_MASK; | |
416 | return 1; | |
417 | } | |
418 | ||
419 | __setup("coredump_filter=", coredump_filter_setup); | |
420 | ||
1da177e4 LT |
421 | #include <linux/init_task.h> |
422 | ||
78fb7466 | 423 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
1da177e4 LT |
424 | { |
425 | atomic_set(&mm->mm_users, 1); | |
426 | atomic_set(&mm->mm_count, 1); | |
427 | init_rwsem(&mm->mmap_sem); | |
428 | INIT_LIST_HEAD(&mm->mmlist); | |
4cb0e11b | 429 | mm->flags = (current->mm) ? current->mm->flags : default_dump_filter; |
999d9fc1 | 430 | mm->core_state = NULL; |
1da177e4 | 431 | mm->nr_ptes = 0; |
4294621f | 432 | set_mm_counter(mm, file_rss, 0); |
404351e6 | 433 | set_mm_counter(mm, anon_rss, 0); |
1da177e4 | 434 | spin_lock_init(&mm->page_table_lock); |
abf137dd JA |
435 | spin_lock_init(&mm->ioctx_lock); |
436 | INIT_HLIST_HEAD(&mm->ioctx_list); | |
1da177e4 | 437 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1363c3cd | 438 | mm->cached_hole_size = ~0UL; |
cf475ad2 | 439 | mm_init_owner(mm, p); |
1da177e4 LT |
440 | |
441 | if (likely(!mm_alloc_pgd(mm))) { | |
442 | mm->def_flags = 0; | |
cddb8a5c | 443 | mmu_notifier_mm_init(mm); |
1da177e4 LT |
444 | return mm; |
445 | } | |
78fb7466 | 446 | |
1da177e4 LT |
447 | free_mm(mm); |
448 | return NULL; | |
449 | } | |
450 | ||
451 | /* | |
452 | * Allocate and initialize an mm_struct. | |
453 | */ | |
454 | struct mm_struct * mm_alloc(void) | |
455 | { | |
456 | struct mm_struct * mm; | |
457 | ||
458 | mm = allocate_mm(); | |
459 | if (mm) { | |
460 | memset(mm, 0, sizeof(*mm)); | |
78fb7466 | 461 | mm = mm_init(mm, current); |
1da177e4 LT |
462 | } |
463 | return mm; | |
464 | } | |
465 | ||
466 | /* | |
467 | * Called when the last reference to the mm | |
468 | * is dropped: either by a lazy thread or by | |
469 | * mmput. Free the page directory and the mm. | |
470 | */ | |
7ad5b3a5 | 471 | void __mmdrop(struct mm_struct *mm) |
1da177e4 LT |
472 | { |
473 | BUG_ON(mm == &init_mm); | |
474 | mm_free_pgd(mm); | |
475 | destroy_context(mm); | |
cddb8a5c | 476 | mmu_notifier_mm_destroy(mm); |
1da177e4 LT |
477 | free_mm(mm); |
478 | } | |
6d4e4c4f | 479 | EXPORT_SYMBOL_GPL(__mmdrop); |
1da177e4 LT |
480 | |
481 | /* | |
482 | * Decrement the use count and release all resources for an mm. | |
483 | */ | |
484 | void mmput(struct mm_struct *mm) | |
485 | { | |
0ae26f1b AM |
486 | might_sleep(); |
487 | ||
1da177e4 LT |
488 | if (atomic_dec_and_test(&mm->mm_users)) { |
489 | exit_aio(mm); | |
490 | exit_mmap(mm); | |
925d1c40 | 491 | set_mm_exe_file(mm, NULL); |
1da177e4 LT |
492 | if (!list_empty(&mm->mmlist)) { |
493 | spin_lock(&mmlist_lock); | |
494 | list_del(&mm->mmlist); | |
495 | spin_unlock(&mmlist_lock); | |
496 | } | |
497 | put_swap_token(mm); | |
498 | mmdrop(mm); | |
499 | } | |
500 | } | |
501 | EXPORT_SYMBOL_GPL(mmput); | |
502 | ||
503 | /** | |
504 | * get_task_mm - acquire a reference to the task's mm | |
505 | * | |
246bb0b1 | 506 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
1da177e4 LT |
507 | * this kernel workthread has transiently adopted a user mm with use_mm, |
508 | * to do its AIO) is not set and if so returns a reference to it, after | |
509 | * bumping up the use count. User must release the mm via mmput() | |
510 | * after use. Typically used by /proc and ptrace. | |
511 | */ | |
512 | struct mm_struct *get_task_mm(struct task_struct *task) | |
513 | { | |
514 | struct mm_struct *mm; | |
515 | ||
516 | task_lock(task); | |
517 | mm = task->mm; | |
518 | if (mm) { | |
246bb0b1 | 519 | if (task->flags & PF_KTHREAD) |
1da177e4 LT |
520 | mm = NULL; |
521 | else | |
522 | atomic_inc(&mm->mm_users); | |
523 | } | |
524 | task_unlock(task); | |
525 | return mm; | |
526 | } | |
527 | EXPORT_SYMBOL_GPL(get_task_mm); | |
528 | ||
529 | /* Please note the differences between mmput and mm_release. | |
530 | * mmput is called whenever we stop holding onto a mm_struct, | |
531 | * error success whatever. | |
532 | * | |
533 | * mm_release is called after a mm_struct has been removed | |
534 | * from the current process. | |
535 | * | |
536 | * This difference is important for error handling, when we | |
537 | * only half set up a mm_struct for a new process and need to restore | |
538 | * the old one. Because we mmput the new mm_struct before | |
539 | * restoring the old one. . . | |
540 | * Eric Biederman 10 January 1998 | |
541 | */ | |
542 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) | |
543 | { | |
544 | struct completion *vfork_done = tsk->vfork_done; | |
545 | ||
8141c7f3 LT |
546 | /* Get rid of any futexes when releasing the mm */ |
547 | #ifdef CONFIG_FUTEX | |
548 | if (unlikely(tsk->robust_list)) | |
549 | exit_robust_list(tsk); | |
550 | #ifdef CONFIG_COMPAT | |
551 | if (unlikely(tsk->compat_robust_list)) | |
552 | compat_exit_robust_list(tsk); | |
553 | #endif | |
554 | #endif | |
555 | ||
1da177e4 LT |
556 | /* Get rid of any cached register state */ |
557 | deactivate_mm(tsk, mm); | |
558 | ||
559 | /* notify parent sleeping on vfork() */ | |
560 | if (vfork_done) { | |
561 | tsk->vfork_done = NULL; | |
562 | complete(vfork_done); | |
563 | } | |
fec1d011 RM |
564 | |
565 | /* | |
566 | * If we're exiting normally, clear a user-space tid field if | |
567 | * requested. We leave this alone when dying by signal, to leave | |
568 | * the value intact in a core dump, and to save the unnecessary | |
569 | * trouble otherwise. Userland only wants this done for a sys_exit. | |
570 | */ | |
571 | if (tsk->clear_child_tid | |
572 | && !(tsk->flags & PF_SIGNALED) | |
573 | && atomic_read(&mm->mm_users) > 1) { | |
1da177e4 LT |
574 | u32 __user * tidptr = tsk->clear_child_tid; |
575 | tsk->clear_child_tid = NULL; | |
576 | ||
577 | /* | |
578 | * We don't check the error code - if userspace has | |
579 | * not set up a proper pointer then tough luck. | |
580 | */ | |
581 | put_user(0, tidptr); | |
582 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); | |
583 | } | |
584 | } | |
585 | ||
a0a7ec30 JD |
586 | /* |
587 | * Allocate a new mm structure and copy contents from the | |
588 | * mm structure of the passed in task structure. | |
589 | */ | |
402b0862 | 590 | struct mm_struct *dup_mm(struct task_struct *tsk) |
a0a7ec30 JD |
591 | { |
592 | struct mm_struct *mm, *oldmm = current->mm; | |
593 | int err; | |
594 | ||
595 | if (!oldmm) | |
596 | return NULL; | |
597 | ||
598 | mm = allocate_mm(); | |
599 | if (!mm) | |
600 | goto fail_nomem; | |
601 | ||
602 | memcpy(mm, oldmm, sizeof(*mm)); | |
603 | ||
7602bdf2 AC |
604 | /* Initializing for Swap token stuff */ |
605 | mm->token_priority = 0; | |
606 | mm->last_interval = 0; | |
607 | ||
78fb7466 | 608 | if (!mm_init(mm, tsk)) |
a0a7ec30 JD |
609 | goto fail_nomem; |
610 | ||
611 | if (init_new_context(tsk, mm)) | |
612 | goto fail_nocontext; | |
613 | ||
925d1c40 MH |
614 | dup_mm_exe_file(oldmm, mm); |
615 | ||
a0a7ec30 JD |
616 | err = dup_mmap(mm, oldmm); |
617 | if (err) | |
618 | goto free_pt; | |
619 | ||
620 | mm->hiwater_rss = get_mm_rss(mm); | |
621 | mm->hiwater_vm = mm->total_vm; | |
622 | ||
623 | return mm; | |
624 | ||
625 | free_pt: | |
626 | mmput(mm); | |
627 | ||
628 | fail_nomem: | |
629 | return NULL; | |
630 | ||
631 | fail_nocontext: | |
632 | /* | |
633 | * If init_new_context() failed, we cannot use mmput() to free the mm | |
634 | * because it calls destroy_context() | |
635 | */ | |
636 | mm_free_pgd(mm); | |
637 | free_mm(mm); | |
638 | return NULL; | |
639 | } | |
640 | ||
1da177e4 LT |
641 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
642 | { | |
643 | struct mm_struct * mm, *oldmm; | |
644 | int retval; | |
645 | ||
646 | tsk->min_flt = tsk->maj_flt = 0; | |
647 | tsk->nvcsw = tsk->nivcsw = 0; | |
648 | ||
649 | tsk->mm = NULL; | |
650 | tsk->active_mm = NULL; | |
651 | ||
652 | /* | |
653 | * Are we cloning a kernel thread? | |
654 | * | |
655 | * We need to steal a active VM for that.. | |
656 | */ | |
657 | oldmm = current->mm; | |
658 | if (!oldmm) | |
659 | return 0; | |
660 | ||
661 | if (clone_flags & CLONE_VM) { | |
662 | atomic_inc(&oldmm->mm_users); | |
663 | mm = oldmm; | |
1da177e4 LT |
664 | goto good_mm; |
665 | } | |
666 | ||
667 | retval = -ENOMEM; | |
a0a7ec30 | 668 | mm = dup_mm(tsk); |
1da177e4 LT |
669 | if (!mm) |
670 | goto fail_nomem; | |
671 | ||
1da177e4 | 672 | good_mm: |
7602bdf2 AC |
673 | /* Initializing for Swap token stuff */ |
674 | mm->token_priority = 0; | |
675 | mm->last_interval = 0; | |
676 | ||
1da177e4 LT |
677 | tsk->mm = mm; |
678 | tsk->active_mm = mm; | |
679 | return 0; | |
680 | ||
1da177e4 LT |
681 | fail_nomem: |
682 | return retval; | |
1da177e4 LT |
683 | } |
684 | ||
a39bc516 | 685 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 | 686 | { |
498052bb | 687 | struct fs_struct *fs = current->fs; |
1da177e4 | 688 | if (clone_flags & CLONE_FS) { |
498052bb AV |
689 | /* tsk->fs is already what we want */ |
690 | write_lock(&fs->lock); | |
691 | if (fs->in_exec) { | |
692 | write_unlock(&fs->lock); | |
693 | return -EAGAIN; | |
694 | } | |
695 | fs->users++; | |
696 | write_unlock(&fs->lock); | |
1da177e4 LT |
697 | return 0; |
698 | } | |
498052bb | 699 | tsk->fs = copy_fs_struct(fs); |
1da177e4 LT |
700 | if (!tsk->fs) |
701 | return -ENOMEM; | |
702 | return 0; | |
703 | } | |
704 | ||
a016f338 JD |
705 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
706 | { | |
707 | struct files_struct *oldf, *newf; | |
708 | int error = 0; | |
709 | ||
710 | /* | |
711 | * A background process may not have any files ... | |
712 | */ | |
713 | oldf = current->files; | |
714 | if (!oldf) | |
715 | goto out; | |
716 | ||
717 | if (clone_flags & CLONE_FILES) { | |
718 | atomic_inc(&oldf->count); | |
719 | goto out; | |
720 | } | |
721 | ||
a016f338 JD |
722 | newf = dup_fd(oldf, &error); |
723 | if (!newf) | |
724 | goto out; | |
725 | ||
726 | tsk->files = newf; | |
727 | error = 0; | |
728 | out: | |
729 | return error; | |
730 | } | |
731 | ||
fadad878 | 732 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
fd0928df JA |
733 | { |
734 | #ifdef CONFIG_BLOCK | |
735 | struct io_context *ioc = current->io_context; | |
736 | ||
737 | if (!ioc) | |
738 | return 0; | |
fadad878 JA |
739 | /* |
740 | * Share io context with parent, if CLONE_IO is set | |
741 | */ | |
742 | if (clone_flags & CLONE_IO) { | |
743 | tsk->io_context = ioc_task_link(ioc); | |
744 | if (unlikely(!tsk->io_context)) | |
745 | return -ENOMEM; | |
746 | } else if (ioprio_valid(ioc->ioprio)) { | |
fd0928df JA |
747 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
748 | if (unlikely(!tsk->io_context)) | |
749 | return -ENOMEM; | |
750 | ||
fd0928df JA |
751 | tsk->io_context->ioprio = ioc->ioprio; |
752 | } | |
753 | #endif | |
754 | return 0; | |
755 | } | |
756 | ||
a39bc516 | 757 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
758 | { |
759 | struct sighand_struct *sig; | |
760 | ||
60348802 | 761 | if (clone_flags & CLONE_SIGHAND) { |
1da177e4 LT |
762 | atomic_inc(¤t->sighand->count); |
763 | return 0; | |
764 | } | |
765 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
e56d0903 | 766 | rcu_assign_pointer(tsk->sighand, sig); |
1da177e4 LT |
767 | if (!sig) |
768 | return -ENOMEM; | |
1da177e4 LT |
769 | atomic_set(&sig->count, 1); |
770 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); | |
771 | return 0; | |
772 | } | |
773 | ||
a7e5328a | 774 | void __cleanup_sighand(struct sighand_struct *sighand) |
c81addc9 | 775 | { |
c81addc9 ON |
776 | if (atomic_dec_and_test(&sighand->count)) |
777 | kmem_cache_free(sighand_cachep, sighand); | |
778 | } | |
779 | ||
f06febc9 FM |
780 | |
781 | /* | |
782 | * Initialize POSIX timer handling for a thread group. | |
783 | */ | |
784 | static void posix_cpu_timers_init_group(struct signal_struct *sig) | |
785 | { | |
786 | /* Thread group counters. */ | |
787 | thread_group_cputime_init(sig); | |
788 | ||
789 | /* Expiration times and increments. */ | |
790 | sig->it_virt_expires = cputime_zero; | |
791 | sig->it_virt_incr = cputime_zero; | |
792 | sig->it_prof_expires = cputime_zero; | |
793 | sig->it_prof_incr = cputime_zero; | |
794 | ||
795 | /* Cached expiration times. */ | |
796 | sig->cputime_expires.prof_exp = cputime_zero; | |
797 | sig->cputime_expires.virt_exp = cputime_zero; | |
798 | sig->cputime_expires.sched_exp = 0; | |
799 | ||
800 | /* The timer lists. */ | |
801 | INIT_LIST_HEAD(&sig->cpu_timers[0]); | |
802 | INIT_LIST_HEAD(&sig->cpu_timers[1]); | |
803 | INIT_LIST_HEAD(&sig->cpu_timers[2]); | |
804 | } | |
805 | ||
a39bc516 | 806 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
1da177e4 LT |
807 | { |
808 | struct signal_struct *sig; | |
1da177e4 LT |
809 | |
810 | if (clone_flags & CLONE_THREAD) { | |
490dea45 PZ |
811 | atomic_inc(¤t->signal->count); |
812 | atomic_inc(¤t->signal->live); | |
813 | return 0; | |
1da177e4 LT |
814 | } |
815 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); | |
490dea45 PZ |
816 | |
817 | if (sig) | |
818 | posix_cpu_timers_init_group(sig); | |
819 | ||
1da177e4 LT |
820 | tsk->signal = sig; |
821 | if (!sig) | |
822 | return -ENOMEM; | |
823 | ||
1da177e4 LT |
824 | atomic_set(&sig->count, 1); |
825 | atomic_set(&sig->live, 1); | |
826 | init_waitqueue_head(&sig->wait_chldexit); | |
827 | sig->flags = 0; | |
b3bfa0cb SB |
828 | if (clone_flags & CLONE_NEWPID) |
829 | sig->flags |= SIGNAL_UNKILLABLE; | |
1da177e4 LT |
830 | sig->group_exit_code = 0; |
831 | sig->group_exit_task = NULL; | |
832 | sig->group_stop_count = 0; | |
db51aecc | 833 | sig->curr_target = tsk; |
1da177e4 LT |
834 | init_sigpending(&sig->shared_pending); |
835 | INIT_LIST_HEAD(&sig->posix_timers); | |
836 | ||
c9cb2e3d | 837 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
2ff678b8 | 838 | sig->it_real_incr.tv64 = 0; |
1da177e4 | 839 | sig->real_timer.function = it_real_fn; |
1da177e4 | 840 | |
1da177e4 | 841 | sig->leader = 0; /* session leadership doesn't inherit */ |
ab521dc0 | 842 | sig->tty_old_pgrp = NULL; |
9c9f4ded | 843 | sig->tty = NULL; |
1da177e4 | 844 | |
32bd671d | 845 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; |
9ac52315 LV |
846 | sig->gtime = cputime_zero; |
847 | sig->cgtime = cputime_zero; | |
1da177e4 LT |
848 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
849 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; | |
6eaeeaba | 850 | sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0; |
5995477a | 851 | task_io_accounting_init(&sig->ioac); |
32bd671d | 852 | sig->sum_sched_runtime = 0; |
ad4ecbcb | 853 | taskstats_tgid_init(sig); |
1da177e4 LT |
854 | |
855 | task_lock(current->group_leader); | |
856 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); | |
857 | task_unlock(current->group_leader); | |
858 | ||
0e464814 | 859 | acct_init_pacct(&sig->pacct); |
1da177e4 | 860 | |
522ed776 MT |
861 | tty_audit_fork(sig); |
862 | ||
1da177e4 LT |
863 | return 0; |
864 | } | |
865 | ||
6b3934ef ON |
866 | void __cleanup_signal(struct signal_struct *sig) |
867 | { | |
f06febc9 | 868 | thread_group_cputime_free(sig); |
9c9f4ded | 869 | tty_kref_put(sig->tty); |
6b3934ef ON |
870 | kmem_cache_free(signal_cachep, sig); |
871 | } | |
872 | ||
a39bc516 | 873 | static void cleanup_signal(struct task_struct *tsk) |
6b3934ef ON |
874 | { |
875 | struct signal_struct *sig = tsk->signal; | |
876 | ||
877 | atomic_dec(&sig->live); | |
878 | ||
879 | if (atomic_dec_and_test(&sig->count)) | |
880 | __cleanup_signal(sig); | |
881 | } | |
882 | ||
a39bc516 | 883 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
1da177e4 LT |
884 | { |
885 | unsigned long new_flags = p->flags; | |
886 | ||
83144186 | 887 | new_flags &= ~PF_SUPERPRIV; |
1da177e4 | 888 | new_flags |= PF_FORKNOEXEC; |
09a05394 | 889 | new_flags |= PF_STARTING; |
1da177e4 | 890 | p->flags = new_flags; |
2e131895 | 891 | clear_freeze_flag(p); |
1da177e4 LT |
892 | } |
893 | ||
17da2bd9 | 894 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
1da177e4 LT |
895 | { |
896 | current->clear_child_tid = tidptr; | |
897 | ||
b488893a | 898 | return task_pid_vnr(current); |
1da177e4 LT |
899 | } |
900 | ||
a39bc516 | 901 | static void rt_mutex_init_task(struct task_struct *p) |
23f78d4a | 902 | { |
23f78d4a | 903 | spin_lock_init(&p->pi_lock); |
e29e175b | 904 | #ifdef CONFIG_RT_MUTEXES |
23f78d4a IM |
905 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
906 | p->pi_blocked_on = NULL; | |
23f78d4a IM |
907 | #endif |
908 | } | |
909 | ||
cf475ad2 BS |
910 | #ifdef CONFIG_MM_OWNER |
911 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) | |
912 | { | |
913 | mm->owner = p; | |
914 | } | |
915 | #endif /* CONFIG_MM_OWNER */ | |
916 | ||
f06febc9 FM |
917 | /* |
918 | * Initialize POSIX timer handling for a single task. | |
919 | */ | |
920 | static void posix_cpu_timers_init(struct task_struct *tsk) | |
921 | { | |
922 | tsk->cputime_expires.prof_exp = cputime_zero; | |
923 | tsk->cputime_expires.virt_exp = cputime_zero; | |
924 | tsk->cputime_expires.sched_exp = 0; | |
925 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); | |
926 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); | |
927 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); | |
928 | } | |
929 | ||
1da177e4 LT |
930 | /* |
931 | * This creates a new process as a copy of the old one, | |
932 | * but does not actually start it yet. | |
933 | * | |
934 | * It copies the registers, and all the appropriate | |
935 | * parts of the process environment (as per the clone | |
936 | * flags). The actual kick-off is left to the caller. | |
937 | */ | |
36c8b586 IM |
938 | static struct task_struct *copy_process(unsigned long clone_flags, |
939 | unsigned long stack_start, | |
940 | struct pt_regs *regs, | |
941 | unsigned long stack_size, | |
36c8b586 | 942 | int __user *child_tidptr, |
09a05394 RM |
943 | struct pid *pid, |
944 | int trace) | |
1da177e4 LT |
945 | { |
946 | int retval; | |
a24efe62 | 947 | struct task_struct *p; |
b4f48b63 | 948 | int cgroup_callbacks_done = 0; |
1da177e4 LT |
949 | |
950 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) | |
951 | return ERR_PTR(-EINVAL); | |
952 | ||
953 | /* | |
954 | * Thread groups must share signals as well, and detached threads | |
955 | * can only be started up within the thread group. | |
956 | */ | |
957 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) | |
958 | return ERR_PTR(-EINVAL); | |
959 | ||
960 | /* | |
961 | * Shared signal handlers imply shared VM. By way of the above, | |
962 | * thread groups also imply shared VM. Blocking this case allows | |
963 | * for various simplifications in other code. | |
964 | */ | |
965 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) | |
966 | return ERR_PTR(-EINVAL); | |
967 | ||
968 | retval = security_task_create(clone_flags); | |
969 | if (retval) | |
970 | goto fork_out; | |
971 | ||
972 | retval = -ENOMEM; | |
973 | p = dup_task_struct(current); | |
974 | if (!p) | |
975 | goto fork_out; | |
976 | ||
bea493a0 PZ |
977 | rt_mutex_init_task(p); |
978 | ||
d12c1a37 | 979 | #ifdef CONFIG_PROVE_LOCKING |
de30a2b3 IM |
980 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
981 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); | |
982 | #endif | |
1da177e4 | 983 | retval = -EAGAIN; |
3b11a1de | 984 | if (atomic_read(&p->real_cred->user->processes) >= |
1da177e4 LT |
985 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { |
986 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && | |
18b6e041 | 987 | p->real_cred->user != INIT_USER) |
1da177e4 LT |
988 | goto bad_fork_free; |
989 | } | |
990 | ||
f1752eec DH |
991 | retval = copy_creds(p, clone_flags); |
992 | if (retval < 0) | |
993 | goto bad_fork_free; | |
1da177e4 LT |
994 | |
995 | /* | |
996 | * If multiple threads are within copy_process(), then this check | |
997 | * triggers too late. This doesn't hurt, the check is only there | |
998 | * to stop root fork bombs. | |
999 | */ | |
04ec93fe | 1000 | retval = -EAGAIN; |
1da177e4 LT |
1001 | if (nr_threads >= max_threads) |
1002 | goto bad_fork_cleanup_count; | |
1003 | ||
a1261f54 | 1004 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
1da177e4 LT |
1005 | goto bad_fork_cleanup_count; |
1006 | ||
1007 | if (p->binfmt && !try_module_get(p->binfmt->module)) | |
1008 | goto bad_fork_cleanup_put_domain; | |
1009 | ||
1010 | p->did_exec = 0; | |
ca74e92b | 1011 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
1da177e4 | 1012 | copy_flags(clone_flags, p); |
1da177e4 LT |
1013 | INIT_LIST_HEAD(&p->children); |
1014 | INIT_LIST_HEAD(&p->sibling); | |
e260be67 PM |
1015 | #ifdef CONFIG_PREEMPT_RCU |
1016 | p->rcu_read_lock_nesting = 0; | |
1017 | p->rcu_flipctr_idx = 0; | |
1018 | #endif /* #ifdef CONFIG_PREEMPT_RCU */ | |
1da177e4 LT |
1019 | p->vfork_done = NULL; |
1020 | spin_lock_init(&p->alloc_lock); | |
1da177e4 LT |
1021 | |
1022 | clear_tsk_thread_flag(p, TIF_SIGPENDING); | |
1023 | init_sigpending(&p->pending); | |
1024 | ||
1025 | p->utime = cputime_zero; | |
1026 | p->stime = cputime_zero; | |
9ac52315 | 1027 | p->gtime = cputime_zero; |
c66f08be MN |
1028 | p->utimescaled = cputime_zero; |
1029 | p->stimescaled = cputime_zero; | |
73a2bcb0 | 1030 | p->prev_utime = cputime_zero; |
9301899b | 1031 | p->prev_stime = cputime_zero; |
172ba844 | 1032 | |
6976675d AV |
1033 | p->default_timer_slack_ns = current->timer_slack_ns; |
1034 | ||
82a1fcb9 IM |
1035 | #ifdef CONFIG_DETECT_SOFTLOCKUP |
1036 | p->last_switch_count = 0; | |
1037 | p->last_switch_timestamp = 0; | |
1038 | #endif | |
1039 | ||
5995477a | 1040 | task_io_accounting_init(&p->ioac); |
1da177e4 LT |
1041 | acct_clear_integrals(p); |
1042 | ||
f06febc9 | 1043 | posix_cpu_timers_init(p); |
1da177e4 LT |
1044 | |
1045 | p->lock_depth = -1; /* -1 = no lock */ | |
1046 | do_posix_clock_monotonic_gettime(&p->start_time); | |
924b42d5 TJ |
1047 | p->real_start_time = p->start_time; |
1048 | monotonic_to_bootbased(&p->real_start_time); | |
1da177e4 | 1049 | p->io_context = NULL; |
1da177e4 | 1050 | p->audit_context = NULL; |
b4f48b63 | 1051 | cgroup_fork(p); |
1da177e4 | 1052 | #ifdef CONFIG_NUMA |
846a16bf | 1053 | p->mempolicy = mpol_dup(p->mempolicy); |
1da177e4 LT |
1054 | if (IS_ERR(p->mempolicy)) { |
1055 | retval = PTR_ERR(p->mempolicy); | |
1056 | p->mempolicy = NULL; | |
b4f48b63 | 1057 | goto bad_fork_cleanup_cgroup; |
1da177e4 | 1058 | } |
c61afb18 | 1059 | mpol_fix_fork_child_flag(p); |
1da177e4 | 1060 | #endif |
de30a2b3 IM |
1061 | #ifdef CONFIG_TRACE_IRQFLAGS |
1062 | p->irq_events = 0; | |
b36e4758 RK |
1063 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1064 | p->hardirqs_enabled = 1; | |
1065 | #else | |
de30a2b3 | 1066 | p->hardirqs_enabled = 0; |
b36e4758 | 1067 | #endif |
de30a2b3 IM |
1068 | p->hardirq_enable_ip = 0; |
1069 | p->hardirq_enable_event = 0; | |
1070 | p->hardirq_disable_ip = _THIS_IP_; | |
1071 | p->hardirq_disable_event = 0; | |
1072 | p->softirqs_enabled = 1; | |
1073 | p->softirq_enable_ip = _THIS_IP_; | |
1074 | p->softirq_enable_event = 0; | |
1075 | p->softirq_disable_ip = 0; | |
1076 | p->softirq_disable_event = 0; | |
1077 | p->hardirq_context = 0; | |
1078 | p->softirq_context = 0; | |
1079 | #endif | |
fbb9ce95 IM |
1080 | #ifdef CONFIG_LOCKDEP |
1081 | p->lockdep_depth = 0; /* no locks held yet */ | |
1082 | p->curr_chain_key = 0; | |
1083 | p->lockdep_recursion = 0; | |
1084 | #endif | |
1da177e4 | 1085 | |
408894ee IM |
1086 | #ifdef CONFIG_DEBUG_MUTEXES |
1087 | p->blocked_on = NULL; /* not blocked yet */ | |
1088 | #endif | |
06eb23b1 | 1089 | if (unlikely(current->ptrace)) |
bf53de90 | 1090 | ptrace_fork(p, clone_flags); |
408894ee | 1091 | |
3c90e6e9 SV |
1092 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
1093 | sched_fork(p, clone_flags); | |
1094 | ||
1da177e4 | 1095 | if ((retval = audit_alloc(p))) |
f1752eec | 1096 | goto bad_fork_cleanup_policy; |
1da177e4 LT |
1097 | /* copy all the process information */ |
1098 | if ((retval = copy_semundo(clone_flags, p))) | |
1099 | goto bad_fork_cleanup_audit; | |
1100 | if ((retval = copy_files(clone_flags, p))) | |
1101 | goto bad_fork_cleanup_semundo; | |
1102 | if ((retval = copy_fs(clone_flags, p))) | |
1103 | goto bad_fork_cleanup_files; | |
1104 | if ((retval = copy_sighand(clone_flags, p))) | |
1105 | goto bad_fork_cleanup_fs; | |
1106 | if ((retval = copy_signal(clone_flags, p))) | |
1107 | goto bad_fork_cleanup_sighand; | |
1108 | if ((retval = copy_mm(clone_flags, p))) | |
1109 | goto bad_fork_cleanup_signal; | |
ab516013 | 1110 | if ((retval = copy_namespaces(clone_flags, p))) |
d84f4f99 | 1111 | goto bad_fork_cleanup_mm; |
fadad878 | 1112 | if ((retval = copy_io(clone_flags, p))) |
fd0928df | 1113 | goto bad_fork_cleanup_namespaces; |
6f2c55b8 | 1114 | retval = copy_thread(clone_flags, stack_start, stack_size, p, regs); |
1da177e4 | 1115 | if (retval) |
fd0928df | 1116 | goto bad_fork_cleanup_io; |
1da177e4 | 1117 | |
425fb2b4 PE |
1118 | if (pid != &init_struct_pid) { |
1119 | retval = -ENOMEM; | |
61bce0f1 | 1120 | pid = alloc_pid(p->nsproxy->pid_ns); |
425fb2b4 | 1121 | if (!pid) |
fd0928df | 1122 | goto bad_fork_cleanup_io; |
6f4e6433 PE |
1123 | |
1124 | if (clone_flags & CLONE_NEWPID) { | |
61bce0f1 | 1125 | retval = pid_ns_prepare_proc(p->nsproxy->pid_ns); |
6f4e6433 PE |
1126 | if (retval < 0) |
1127 | goto bad_fork_free_pid; | |
1128 | } | |
425fb2b4 PE |
1129 | } |
1130 | ||
e8e1abe9 SR |
1131 | ftrace_graph_init_task(p); |
1132 | ||
425fb2b4 PE |
1133 | p->pid = pid_nr(pid); |
1134 | p->tgid = p->pid; | |
1135 | if (clone_flags & CLONE_THREAD) | |
1136 | p->tgid = current->tgid; | |
1137 | ||
e885dcde SH |
1138 | if (current->nsproxy != p->nsproxy) { |
1139 | retval = ns_cgroup_clone(p, pid); | |
1140 | if (retval) | |
e8e1abe9 | 1141 | goto bad_fork_free_graph; |
e885dcde SH |
1142 | } |
1143 | ||
1da177e4 LT |
1144 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
1145 | /* | |
1146 | * Clear TID on mm_release()? | |
1147 | */ | |
1148 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; | |
42b2dd0a | 1149 | #ifdef CONFIG_FUTEX |
8f17d3a5 IM |
1150 | p->robust_list = NULL; |
1151 | #ifdef CONFIG_COMPAT | |
1152 | p->compat_robust_list = NULL; | |
1153 | #endif | |
c87e2837 IM |
1154 | INIT_LIST_HEAD(&p->pi_state_list); |
1155 | p->pi_state_cache = NULL; | |
42b2dd0a | 1156 | #endif |
f9a3879a GM |
1157 | /* |
1158 | * sigaltstack should be cleared when sharing the same VM | |
1159 | */ | |
1160 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) | |
1161 | p->sas_ss_sp = p->sas_ss_size = 0; | |
1162 | ||
1da177e4 LT |
1163 | /* |
1164 | * Syscall tracing should be turned off in the child regardless | |
1165 | * of CLONE_PTRACE. | |
1166 | */ | |
1167 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); | |
ed75e8d5 LV |
1168 | #ifdef TIF_SYSCALL_EMU |
1169 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); | |
1170 | #endif | |
9745512c | 1171 | clear_all_latency_tracing(p); |
1da177e4 | 1172 | |
1da177e4 LT |
1173 | /* ok, now we should be set up.. */ |
1174 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); | |
1175 | p->pdeath_signal = 0; | |
1176 | p->exit_state = 0; | |
1177 | ||
1da177e4 LT |
1178 | /* |
1179 | * Ok, make it visible to the rest of the system. | |
1180 | * We dont wake it up yet. | |
1181 | */ | |
1182 | p->group_leader = p; | |
47e65328 | 1183 | INIT_LIST_HEAD(&p->thread_group); |
1da177e4 | 1184 | |
b4f48b63 PM |
1185 | /* Now that the task is set up, run cgroup callbacks if |
1186 | * necessary. We need to run them before the task is visible | |
1187 | * on the tasklist. */ | |
1188 | cgroup_fork_callbacks(p); | |
1189 | cgroup_callbacks_done = 1; | |
1190 | ||
1da177e4 LT |
1191 | /* Need tasklist lock for parent etc handling! */ |
1192 | write_lock_irq(&tasklist_lock); | |
1193 | ||
1194 | /* | |
476d139c NP |
1195 | * The task hasn't been attached yet, so its cpus_allowed mask will |
1196 | * not be changed, nor will its assigned CPU. | |
1197 | * | |
1198 | * The cpus_allowed mask of the parent may have changed after it was | |
1199 | * copied first time - so re-copy it here, then check the child's CPU | |
1200 | * to ensure it is on a valid CPU (and if not, just force it back to | |
1201 | * parent's CPU). This avoids alot of nasty races. | |
1da177e4 LT |
1202 | */ |
1203 | p->cpus_allowed = current->cpus_allowed; | |
6f505b16 | 1204 | p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed; |
26ff6ad9 SV |
1205 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
1206 | !cpu_online(task_cpu(p)))) | |
476d139c | 1207 | set_task_cpu(p, smp_processor_id()); |
1da177e4 | 1208 | |
1da177e4 | 1209 | /* CLONE_PARENT re-uses the old parent */ |
2d5516cb | 1210 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
1da177e4 | 1211 | p->real_parent = current->real_parent; |
2d5516cb ON |
1212 | p->parent_exec_id = current->parent_exec_id; |
1213 | } else { | |
1da177e4 | 1214 | p->real_parent = current; |
2d5516cb ON |
1215 | p->parent_exec_id = current->self_exec_id; |
1216 | } | |
1da177e4 | 1217 | |
3f17da69 | 1218 | spin_lock(¤t->sighand->siglock); |
4a2c7a78 ON |
1219 | |
1220 | /* | |
1221 | * Process group and session signals need to be delivered to just the | |
1222 | * parent before the fork or both the parent and the child after the | |
1223 | * fork. Restart if a signal comes in before we add the new process to | |
1224 | * it's process group. | |
1225 | * A fatal signal pending means that current will exit, so the new | |
1226 | * thread can't slip out of an OOM kill (or normal SIGKILL). | |
1227 | */ | |
23ff4440 | 1228 | recalc_sigpending(); |
4a2c7a78 ON |
1229 | if (signal_pending(current)) { |
1230 | spin_unlock(¤t->sighand->siglock); | |
1231 | write_unlock_irq(&tasklist_lock); | |
1232 | retval = -ERESTARTNOINTR; | |
e8e1abe9 | 1233 | goto bad_fork_free_graph; |
4a2c7a78 ON |
1234 | } |
1235 | ||
1da177e4 | 1236 | if (clone_flags & CLONE_THREAD) { |
1da177e4 | 1237 | p->group_leader = current->group_leader; |
47e65328 | 1238 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
1da177e4 LT |
1239 | } |
1240 | ||
73b9ebfe | 1241 | if (likely(p->pid)) { |
f470021a | 1242 | list_add_tail(&p->sibling, &p->real_parent->children); |
09a05394 | 1243 | tracehook_finish_clone(p, clone_flags, trace); |
73b9ebfe ON |
1244 | |
1245 | if (thread_group_leader(p)) { | |
5cd17569 | 1246 | if (clone_flags & CLONE_NEWPID) |
30e49c26 | 1247 | p->nsproxy->pid_ns->child_reaper = p; |
73b9ebfe | 1248 | |
fea9d175 | 1249 | p->signal->leader_pid = pid; |
9c9f4ded AC |
1250 | tty_kref_put(p->signal->tty); |
1251 | p->signal->tty = tty_kref_get(current->signal->tty); | |
5cd17569 EB |
1252 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
1253 | attach_pid(p, PIDTYPE_SID, task_session(current)); | |
5e85d4ab | 1254 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
1da177e4 | 1255 | __get_cpu_var(process_counts)++; |
73b9ebfe | 1256 | } |
85868995 | 1257 | attach_pid(p, PIDTYPE_PID, pid); |
73b9ebfe | 1258 | nr_threads++; |
1da177e4 LT |
1259 | } |
1260 | ||
1da177e4 | 1261 | total_forks++; |
3f17da69 | 1262 | spin_unlock(¤t->sighand->siglock); |
1da177e4 | 1263 | write_unlock_irq(&tasklist_lock); |
c13cf856 | 1264 | proc_fork_connector(p); |
817929ec | 1265 | cgroup_post_fork(p); |
1da177e4 LT |
1266 | return p; |
1267 | ||
e8e1abe9 SR |
1268 | bad_fork_free_graph: |
1269 | ftrace_graph_exit_task(p); | |
425fb2b4 PE |
1270 | bad_fork_free_pid: |
1271 | if (pid != &init_struct_pid) | |
1272 | free_pid(pid); | |
fd0928df JA |
1273 | bad_fork_cleanup_io: |
1274 | put_io_context(p->io_context); | |
ab516013 | 1275 | bad_fork_cleanup_namespaces: |
444f378b | 1276 | exit_task_namespaces(p); |
1da177e4 LT |
1277 | bad_fork_cleanup_mm: |
1278 | if (p->mm) | |
1279 | mmput(p->mm); | |
1280 | bad_fork_cleanup_signal: | |
6b3934ef | 1281 | cleanup_signal(p); |
1da177e4 | 1282 | bad_fork_cleanup_sighand: |
a7e5328a | 1283 | __cleanup_sighand(p->sighand); |
1da177e4 LT |
1284 | bad_fork_cleanup_fs: |
1285 | exit_fs(p); /* blocking */ | |
1286 | bad_fork_cleanup_files: | |
1287 | exit_files(p); /* blocking */ | |
1288 | bad_fork_cleanup_semundo: | |
1289 | exit_sem(p); | |
1290 | bad_fork_cleanup_audit: | |
1291 | audit_free(p); | |
1da177e4 LT |
1292 | bad_fork_cleanup_policy: |
1293 | #ifdef CONFIG_NUMA | |
f0be3d32 | 1294 | mpol_put(p->mempolicy); |
b4f48b63 | 1295 | bad_fork_cleanup_cgroup: |
1da177e4 | 1296 | #endif |
b4f48b63 | 1297 | cgroup_exit(p, cgroup_callbacks_done); |
35df17c5 | 1298 | delayacct_tsk_free(p); |
1da177e4 LT |
1299 | if (p->binfmt) |
1300 | module_put(p->binfmt->module); | |
1301 | bad_fork_cleanup_put_domain: | |
a1261f54 | 1302 | module_put(task_thread_info(p)->exec_domain->module); |
1da177e4 | 1303 | bad_fork_cleanup_count: |
d84f4f99 | 1304 | atomic_dec(&p->cred->user->processes); |
3b11a1de | 1305 | put_cred(p->real_cred); |
f1752eec | 1306 | put_cred(p->cred); |
1da177e4 LT |
1307 | bad_fork_free: |
1308 | free_task(p); | |
fe7d37d1 ON |
1309 | fork_out: |
1310 | return ERR_PTR(retval); | |
1da177e4 LT |
1311 | } |
1312 | ||
6b2fb3c6 | 1313 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
1da177e4 LT |
1314 | { |
1315 | memset(regs, 0, sizeof(struct pt_regs)); | |
1316 | return regs; | |
1317 | } | |
1318 | ||
9abcf40b | 1319 | struct task_struct * __cpuinit fork_idle(int cpu) |
1da177e4 | 1320 | { |
36c8b586 | 1321 | struct task_struct *task; |
1da177e4 LT |
1322 | struct pt_regs regs; |
1323 | ||
30e49c26 | 1324 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
09a05394 | 1325 | &init_struct_pid, 0); |
753ca4f3 AM |
1326 | if (!IS_ERR(task)) |
1327 | init_idle(task, cpu); | |
73b9ebfe | 1328 | |
1da177e4 LT |
1329 | return task; |
1330 | } | |
1331 | ||
1da177e4 LT |
1332 | /* |
1333 | * Ok, this is the main fork-routine. | |
1334 | * | |
1335 | * It copies the process, and if successful kick-starts | |
1336 | * it and waits for it to finish using the VM if required. | |
1337 | */ | |
1338 | long do_fork(unsigned long clone_flags, | |
1339 | unsigned long stack_start, | |
1340 | struct pt_regs *regs, | |
1341 | unsigned long stack_size, | |
1342 | int __user *parent_tidptr, | |
1343 | int __user *child_tidptr) | |
1344 | { | |
1345 | struct task_struct *p; | |
1346 | int trace = 0; | |
92476d7f | 1347 | long nr; |
1da177e4 | 1348 | |
18b6e041 SH |
1349 | /* |
1350 | * Do some preliminary argument and permissions checking before we | |
1351 | * actually start allocating stuff | |
1352 | */ | |
1353 | if (clone_flags & CLONE_NEWUSER) { | |
1354 | if (clone_flags & CLONE_THREAD) | |
1355 | return -EINVAL; | |
1356 | /* hopefully this check will go away when userns support is | |
1357 | * complete | |
1358 | */ | |
7657d904 SH |
1359 | if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) || |
1360 | !capable(CAP_SETGID)) | |
18b6e041 SH |
1361 | return -EPERM; |
1362 | } | |
1363 | ||
bdff746a AM |
1364 | /* |
1365 | * We hope to recycle these flags after 2.6.26 | |
1366 | */ | |
1367 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1368 | static int __read_mostly count = 100; | |
1369 | ||
1370 | if (count > 0 && printk_ratelimit()) { | |
1371 | char comm[TASK_COMM_LEN]; | |
1372 | ||
1373 | count--; | |
1374 | printk(KERN_INFO "fork(): process `%s' used deprecated " | |
1375 | "clone flags 0x%lx\n", | |
1376 | get_task_comm(comm, current), | |
1377 | clone_flags & CLONE_STOPPED); | |
1378 | } | |
1379 | } | |
1380 | ||
09a05394 RM |
1381 | /* |
1382 | * When called from kernel_thread, don't do user tracing stuff. | |
1383 | */ | |
1384 | if (likely(user_mode(regs))) | |
1385 | trace = tracehook_prepare_clone(clone_flags); | |
1da177e4 | 1386 | |
a6f5e063 | 1387 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
09a05394 | 1388 | child_tidptr, NULL, trace); |
1da177e4 LT |
1389 | /* |
1390 | * Do this prior waking up the new thread - the thread pointer | |
1391 | * might get invalid after that point, if the thread exits quickly. | |
1392 | */ | |
1393 | if (!IS_ERR(p)) { | |
1394 | struct completion vfork; | |
1395 | ||
0a16b607 MD |
1396 | trace_sched_process_fork(current, p); |
1397 | ||
6c5f3e7b | 1398 | nr = task_pid_vnr(p); |
30e49c26 PE |
1399 | |
1400 | if (clone_flags & CLONE_PARENT_SETTID) | |
1401 | put_user(nr, parent_tidptr); | |
a6f5e063 | 1402 | |
1da177e4 LT |
1403 | if (clone_flags & CLONE_VFORK) { |
1404 | p->vfork_done = &vfork; | |
1405 | init_completion(&vfork); | |
1406 | } | |
1407 | ||
a64e6494 | 1408 | audit_finish_fork(p); |
09a05394 RM |
1409 | tracehook_report_clone(trace, regs, clone_flags, nr, p); |
1410 | ||
1411 | /* | |
1412 | * We set PF_STARTING at creation in case tracing wants to | |
1413 | * use this to distinguish a fully live task from one that | |
1414 | * hasn't gotten to tracehook_report_clone() yet. Now we | |
1415 | * clear it and set the child going. | |
1416 | */ | |
1417 | p->flags &= ~PF_STARTING; | |
1418 | ||
1419 | if (unlikely(clone_flags & CLONE_STOPPED)) { | |
1da177e4 LT |
1420 | /* |
1421 | * We'll start up with an immediate SIGSTOP. | |
1422 | */ | |
1423 | sigaddset(&p->pending.signal, SIGSTOP); | |
1424 | set_tsk_thread_flag(p, TIF_SIGPENDING); | |
d9ae90ac | 1425 | __set_task_state(p, TASK_STOPPED); |
09a05394 RM |
1426 | } else { |
1427 | wake_up_new_task(p, clone_flags); | |
1da177e4 LT |
1428 | } |
1429 | ||
09a05394 RM |
1430 | tracehook_report_clone_complete(trace, regs, |
1431 | clone_flags, nr, p); | |
1432 | ||
1da177e4 | 1433 | if (clone_flags & CLONE_VFORK) { |
ba96a0c8 | 1434 | freezer_do_not_count(); |
1da177e4 | 1435 | wait_for_completion(&vfork); |
ba96a0c8 | 1436 | freezer_count(); |
daded34b | 1437 | tracehook_report_vfork_done(p, nr); |
1da177e4 LT |
1438 | } |
1439 | } else { | |
92476d7f | 1440 | nr = PTR_ERR(p); |
1da177e4 | 1441 | } |
92476d7f | 1442 | return nr; |
1da177e4 LT |
1443 | } |
1444 | ||
5fd63b30 RT |
1445 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
1446 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 | |
1447 | #endif | |
1448 | ||
51cc5068 | 1449 | static void sighand_ctor(void *data) |
aa1757f9 ON |
1450 | { |
1451 | struct sighand_struct *sighand = data; | |
1452 | ||
a35afb83 | 1453 | spin_lock_init(&sighand->siglock); |
b8fceee1 | 1454 | init_waitqueue_head(&sighand->signalfd_wqh); |
aa1757f9 ON |
1455 | } |
1456 | ||
1da177e4 LT |
1457 | void __init proc_caches_init(void) |
1458 | { | |
1459 | sighand_cachep = kmem_cache_create("sighand_cache", | |
1460 | sizeof(struct sighand_struct), 0, | |
aa1757f9 | 1461 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
20c2df83 | 1462 | sighand_ctor); |
1da177e4 LT |
1463 | signal_cachep = kmem_cache_create("signal_cache", |
1464 | sizeof(struct signal_struct), 0, | |
20c2df83 PM |
1465 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1466 | files_cachep = kmem_cache_create("files_cache", | |
1da177e4 | 1467 | sizeof(struct files_struct), 0, |
20c2df83 PM |
1468 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1469 | fs_cachep = kmem_cache_create("fs_cache", | |
1da177e4 | 1470 | sizeof(struct fs_struct), 0, |
20c2df83 | 1471 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 1472 | mm_cachep = kmem_cache_create("mm_struct", |
5fd63b30 | 1473 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
20c2df83 | 1474 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
33e5d769 | 1475 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC); |
8feae131 | 1476 | mmap_init(); |
1da177e4 | 1477 | } |
cf2e340f | 1478 | |
cf2e340f JD |
1479 | /* |
1480 | * Check constraints on flags passed to the unshare system call and | |
1481 | * force unsharing of additional process context as appropriate. | |
1482 | */ | |
a39bc516 | 1483 | static void check_unshare_flags(unsigned long *flags_ptr) |
cf2e340f JD |
1484 | { |
1485 | /* | |
1486 | * If unsharing a thread from a thread group, must also | |
1487 | * unshare vm. | |
1488 | */ | |
1489 | if (*flags_ptr & CLONE_THREAD) | |
1490 | *flags_ptr |= CLONE_VM; | |
1491 | ||
1492 | /* | |
1493 | * If unsharing vm, must also unshare signal handlers. | |
1494 | */ | |
1495 | if (*flags_ptr & CLONE_VM) | |
1496 | *flags_ptr |= CLONE_SIGHAND; | |
1497 | ||
1498 | /* | |
1499 | * If unsharing signal handlers and the task was created | |
1500 | * using CLONE_THREAD, then must unshare the thread | |
1501 | */ | |
1502 | if ((*flags_ptr & CLONE_SIGHAND) && | |
1503 | (atomic_read(¤t->signal->count) > 1)) | |
1504 | *flags_ptr |= CLONE_THREAD; | |
1505 | ||
1506 | /* | |
1507 | * If unsharing namespace, must also unshare filesystem information. | |
1508 | */ | |
1509 | if (*flags_ptr & CLONE_NEWNS) | |
1510 | *flags_ptr |= CLONE_FS; | |
1511 | } | |
1512 | ||
1513 | /* | |
1514 | * Unsharing of tasks created with CLONE_THREAD is not supported yet | |
1515 | */ | |
1516 | static int unshare_thread(unsigned long unshare_flags) | |
1517 | { | |
1518 | if (unshare_flags & CLONE_THREAD) | |
1519 | return -EINVAL; | |
1520 | ||
1521 | return 0; | |
1522 | } | |
1523 | ||
1524 | /* | |
99d1419d | 1525 | * Unshare the filesystem structure if it is being shared |
cf2e340f JD |
1526 | */ |
1527 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) | |
1528 | { | |
1529 | struct fs_struct *fs = current->fs; | |
1530 | ||
498052bb AV |
1531 | if (!(unshare_flags & CLONE_FS) || !fs) |
1532 | return 0; | |
1533 | ||
1534 | /* don't need lock here; in the worst case we'll do useless copy */ | |
1535 | if (fs->users == 1) | |
1536 | return 0; | |
1537 | ||
1538 | *new_fsp = copy_fs_struct(fs); | |
1539 | if (!*new_fsp) | |
1540 | return -ENOMEM; | |
cf2e340f JD |
1541 | |
1542 | return 0; | |
1543 | } | |
1544 | ||
cf2e340f | 1545 | /* |
dae3c5a0 | 1546 | * Unsharing of sighand is not supported yet |
cf2e340f JD |
1547 | */ |
1548 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) | |
1549 | { | |
1550 | struct sighand_struct *sigh = current->sighand; | |
1551 | ||
dae3c5a0 | 1552 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
cf2e340f JD |
1553 | return -EINVAL; |
1554 | else | |
1555 | return 0; | |
1556 | } | |
1557 | ||
1558 | /* | |
a0a7ec30 | 1559 | * Unshare vm if it is being shared |
cf2e340f JD |
1560 | */ |
1561 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) | |
1562 | { | |
1563 | struct mm_struct *mm = current->mm; | |
1564 | ||
1565 | if ((unshare_flags & CLONE_VM) && | |
a0a7ec30 | 1566 | (mm && atomic_read(&mm->mm_users) > 1)) { |
2d61b867 | 1567 | return -EINVAL; |
a0a7ec30 | 1568 | } |
cf2e340f JD |
1569 | |
1570 | return 0; | |
cf2e340f JD |
1571 | } |
1572 | ||
1573 | /* | |
a016f338 | 1574 | * Unshare file descriptor table if it is being shared |
cf2e340f JD |
1575 | */ |
1576 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) | |
1577 | { | |
1578 | struct files_struct *fd = current->files; | |
a016f338 | 1579 | int error = 0; |
cf2e340f JD |
1580 | |
1581 | if ((unshare_flags & CLONE_FILES) && | |
a016f338 JD |
1582 | (fd && atomic_read(&fd->count) > 1)) { |
1583 | *new_fdp = dup_fd(fd, &error); | |
1584 | if (!*new_fdp) | |
1585 | return error; | |
1586 | } | |
cf2e340f JD |
1587 | |
1588 | return 0; | |
1589 | } | |
1590 | ||
cf2e340f JD |
1591 | /* |
1592 | * unshare allows a process to 'unshare' part of the process | |
1593 | * context which was originally shared using clone. copy_* | |
1594 | * functions used by do_fork() cannot be used here directly | |
1595 | * because they modify an inactive task_struct that is being | |
1596 | * constructed. Here we are modifying the current, active, | |
1597 | * task_struct. | |
1598 | */ | |
6559eed8 | 1599 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
cf2e340f JD |
1600 | { |
1601 | int err = 0; | |
1602 | struct fs_struct *fs, *new_fs = NULL; | |
dae3c5a0 | 1603 | struct sighand_struct *new_sigh = NULL; |
cf2e340f JD |
1604 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
1605 | struct files_struct *fd, *new_fd = NULL; | |
cf7b708c | 1606 | struct nsproxy *new_nsproxy = NULL; |
9edff4ab | 1607 | int do_sysvsem = 0; |
cf2e340f JD |
1608 | |
1609 | check_unshare_flags(&unshare_flags); | |
1610 | ||
06f9d4f9 EB |
1611 | /* Return -EINVAL for all unsupported flags */ |
1612 | err = -EINVAL; | |
1613 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| | |
25b21cb2 | 1614 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
18b6e041 | 1615 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET)) |
06f9d4f9 EB |
1616 | goto bad_unshare_out; |
1617 | ||
6013f67f MS |
1618 | /* |
1619 | * CLONE_NEWIPC must also detach from the undolist: after switching | |
1620 | * to a new ipc namespace, the semaphore arrays from the old | |
1621 | * namespace are unreachable. | |
1622 | */ | |
1623 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) | |
9edff4ab | 1624 | do_sysvsem = 1; |
cf2e340f JD |
1625 | if ((err = unshare_thread(unshare_flags))) |
1626 | goto bad_unshare_out; | |
1627 | if ((err = unshare_fs(unshare_flags, &new_fs))) | |
1628 | goto bad_unshare_cleanup_thread; | |
cf2e340f | 1629 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
e3222c4e | 1630 | goto bad_unshare_cleanup_fs; |
cf2e340f JD |
1631 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
1632 | goto bad_unshare_cleanup_sigh; | |
1633 | if ((err = unshare_fd(unshare_flags, &new_fd))) | |
1634 | goto bad_unshare_cleanup_vm; | |
e3222c4e BP |
1635 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
1636 | new_fs))) | |
9edff4ab | 1637 | goto bad_unshare_cleanup_fd; |
c0b2fc31 | 1638 | |
9edff4ab MS |
1639 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
1640 | if (do_sysvsem) { | |
1641 | /* | |
1642 | * CLONE_SYSVSEM is equivalent to sys_exit(). | |
1643 | */ | |
1644 | exit_sem(current); | |
1645 | } | |
ab516013 | 1646 | |
c0b2fc31 | 1647 | if (new_nsproxy) { |
cf7b708c PE |
1648 | switch_task_namespaces(current, new_nsproxy); |
1649 | new_nsproxy = NULL; | |
c0b2fc31 | 1650 | } |
cf2e340f | 1651 | |
cf7b708c PE |
1652 | task_lock(current); |
1653 | ||
cf2e340f JD |
1654 | if (new_fs) { |
1655 | fs = current->fs; | |
498052bb | 1656 | write_lock(&fs->lock); |
cf2e340f | 1657 | current->fs = new_fs; |
498052bb AV |
1658 | if (--fs->users) |
1659 | new_fs = NULL; | |
1660 | else | |
1661 | new_fs = fs; | |
1662 | write_unlock(&fs->lock); | |
cf2e340f JD |
1663 | } |
1664 | ||
cf2e340f JD |
1665 | if (new_mm) { |
1666 | mm = current->mm; | |
1667 | active_mm = current->active_mm; | |
1668 | current->mm = new_mm; | |
1669 | current->active_mm = new_mm; | |
1670 | activate_mm(active_mm, new_mm); | |
1671 | new_mm = mm; | |
1672 | } | |
1673 | ||
1674 | if (new_fd) { | |
1675 | fd = current->files; | |
1676 | current->files = new_fd; | |
1677 | new_fd = fd; | |
1678 | } | |
1679 | ||
1680 | task_unlock(current); | |
1681 | } | |
1682 | ||
c0b2fc31 | 1683 | if (new_nsproxy) |
444f378b | 1684 | put_nsproxy(new_nsproxy); |
c0b2fc31 | 1685 | |
cf2e340f JD |
1686 | bad_unshare_cleanup_fd: |
1687 | if (new_fd) | |
1688 | put_files_struct(new_fd); | |
1689 | ||
1690 | bad_unshare_cleanup_vm: | |
1691 | if (new_mm) | |
1692 | mmput(new_mm); | |
1693 | ||
1694 | bad_unshare_cleanup_sigh: | |
1695 | if (new_sigh) | |
1696 | if (atomic_dec_and_test(&new_sigh->count)) | |
1697 | kmem_cache_free(sighand_cachep, new_sigh); | |
1698 | ||
cf2e340f JD |
1699 | bad_unshare_cleanup_fs: |
1700 | if (new_fs) | |
498052bb | 1701 | free_fs_struct(new_fs); |
cf2e340f JD |
1702 | |
1703 | bad_unshare_cleanup_thread: | |
1704 | bad_unshare_out: | |
1705 | return err; | |
1706 | } | |
3b125388 AV |
1707 | |
1708 | /* | |
1709 | * Helper to unshare the files of the current task. | |
1710 | * We don't want to expose copy_files internals to | |
1711 | * the exec layer of the kernel. | |
1712 | */ | |
1713 | ||
1714 | int unshare_files(struct files_struct **displaced) | |
1715 | { | |
1716 | struct task_struct *task = current; | |
50704516 | 1717 | struct files_struct *copy = NULL; |
3b125388 AV |
1718 | int error; |
1719 | ||
1720 | error = unshare_fd(CLONE_FILES, ©); | |
1721 | if (error || !copy) { | |
1722 | *displaced = NULL; | |
1723 | return error; | |
1724 | } | |
1725 | *displaced = task->files; | |
1726 | task_lock(task); | |
1727 | task->files = copy; | |
1728 | task_unlock(task); | |
1729 | return 0; | |
1730 | } |