Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/slab.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/unistd.h> |
| 17 | #include <linux/smp_lock.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/vmalloc.h> |
| 20 | #include <linux/completion.h> |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 21 | #include <linux/mnt_namespace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include <linux/personality.h> |
| 23 | #include <linux/mempolicy.h> |
| 24 | #include <linux/sem.h> |
| 25 | #include <linux/file.h> |
| 26 | #include <linux/key.h> |
| 27 | #include <linux/binfmts.h> |
| 28 | #include <linux/mman.h> |
| 29 | #include <linux/fs.h> |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 30 | #include <linux/nsproxy.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 31 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | #include <linux/cpu.h> |
| 33 | #include <linux/cpuset.h> |
| 34 | #include <linux/security.h> |
| 35 | #include <linux/swap.h> |
| 36 | #include <linux/syscalls.h> |
| 37 | #include <linux/jiffies.h> |
| 38 | #include <linux/futex.h> |
Andrew Morton | 7c3ab73 | 2006-12-10 02:19:19 -0800 | [diff] [blame] | 39 | #include <linux/task_io_accounting_ops.h> |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 40 | #include <linux/rcupdate.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | #include <linux/ptrace.h> |
| 42 | #include <linux/mount.h> |
| 43 | #include <linux/audit.h> |
| 44 | #include <linux/profile.h> |
| 45 | #include <linux/rmap.h> |
| 46 | #include <linux/acct.h> |
Jay Lan | 8f0ab51 | 2006-09-30 23:28:59 -0700 | [diff] [blame] | 47 | #include <linux/tsacct_kern.h> |
Matt Helsley | 9f46080 | 2005-11-07 00:59:16 -0800 | [diff] [blame] | 48 | #include <linux/cn_proc.h> |
Shailabh Nagar | ca74e92 | 2006-07-14 00:24:36 -0700 | [diff] [blame] | 49 | #include <linux/delayacct.h> |
Shailabh Nagar | ad4ecbc | 2006-07-14 00:24:44 -0700 | [diff] [blame] | 50 | #include <linux/taskstats_kern.h> |
Arjan van de Ven | 0a42540 | 2006-09-26 10:52:38 +0200 | [diff] [blame] | 51 | #include <linux/random.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | |
| 53 | #include <asm/pgtable.h> |
| 54 | #include <asm/pgalloc.h> |
| 55 | #include <asm/uaccess.h> |
| 56 | #include <asm/mmu_context.h> |
| 57 | #include <asm/cacheflush.h> |
| 58 | #include <asm/tlbflush.h> |
| 59 | |
| 60 | /* |
| 61 | * Protected counters by write_lock_irq(&tasklist_lock) |
| 62 | */ |
| 63 | unsigned long total_forks; /* Handle normal Linux uptimes. */ |
| 64 | int nr_threads; /* The idle threads do not count.. */ |
| 65 | |
| 66 | int max_threads; /* tunable limit on nr_threads */ |
| 67 | |
| 68 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; |
| 69 | |
Christoph Hellwig | c59923a | 2006-07-10 04:45:40 -0700 | [diff] [blame] | 70 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | |
| 72 | int nr_processes(void) |
| 73 | { |
| 74 | int cpu; |
| 75 | int total = 0; |
| 76 | |
| 77 | for_each_online_cpu(cpu) |
| 78 | total += per_cpu(process_counts, cpu); |
| 79 | |
| 80 | return total; |
| 81 | } |
| 82 | |
| 83 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR |
| 84 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) |
| 85 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 86 | static struct kmem_cache *task_struct_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | #endif |
| 88 | |
| 89 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 90 | static struct kmem_cache *signal_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
| 92 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 93 | struct kmem_cache *sighand_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | |
| 95 | /* SLAB cache for files_struct structures (tsk->files) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 96 | struct kmem_cache *files_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | |
| 98 | /* SLAB cache for fs_struct structures (tsk->fs) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 99 | struct kmem_cache *fs_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | |
| 101 | /* SLAB cache for vm_area_struct structures */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 102 | struct kmem_cache *vm_area_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | |
| 104 | /* SLAB cache for mm_struct structures (tsk->mm) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 105 | static struct kmem_cache *mm_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | |
| 107 | void free_task(struct task_struct *tsk) |
| 108 | { |
| 109 | free_thread_info(tsk->thread_info); |
Ingo Molnar | 23f78d4 | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 110 | rt_mutex_debug_task_free(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | free_task_struct(tsk); |
| 112 | } |
| 113 | EXPORT_SYMBOL(free_task); |
| 114 | |
Andrew Morton | 158d9eb | 2006-03-31 02:31:34 -0800 | [diff] [blame] | 115 | void __put_task_struct(struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | { |
| 117 | WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE))); |
| 118 | WARN_ON(atomic_read(&tsk->usage)); |
| 119 | WARN_ON(tsk == current); |
| 120 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | security_task_free(tsk); |
| 122 | free_uid(tsk->user); |
| 123 | put_group_info(tsk->group_info); |
Shailabh Nagar | 35df17c | 2006-08-31 21:27:38 -0700 | [diff] [blame] | 124 | delayacct_tsk_free(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | |
| 126 | if (!profile_handoff_task(tsk)) |
| 127 | free_task(tsk); |
| 128 | } |
| 129 | |
| 130 | void __init fork_init(unsigned long mempages) |
| 131 | { |
| 132 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR |
| 133 | #ifndef ARCH_MIN_TASKALIGN |
| 134 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES |
| 135 | #endif |
| 136 | /* create a slab on which task_structs can be allocated */ |
| 137 | task_struct_cachep = |
| 138 | kmem_cache_create("task_struct", sizeof(struct task_struct), |
| 139 | ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL); |
| 140 | #endif |
| 141 | |
| 142 | /* |
| 143 | * The default maximum number of threads is set to a safe |
| 144 | * value: the thread structures can take up at most half |
| 145 | * of memory. |
| 146 | */ |
| 147 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); |
| 148 | |
| 149 | /* |
| 150 | * we need to allow at least 20 threads to boot a system |
| 151 | */ |
| 152 | if(max_threads < 20) |
| 153 | max_threads = 20; |
| 154 | |
| 155 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; |
| 156 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; |
| 157 | init_task.signal->rlim[RLIMIT_SIGPENDING] = |
| 158 | init_task.signal->rlim[RLIMIT_NPROC]; |
| 159 | } |
| 160 | |
| 161 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
| 162 | { |
| 163 | struct task_struct *tsk; |
| 164 | struct thread_info *ti; |
| 165 | |
| 166 | prepare_to_copy(orig); |
| 167 | |
| 168 | tsk = alloc_task_struct(); |
| 169 | if (!tsk) |
| 170 | return NULL; |
| 171 | |
| 172 | ti = alloc_thread_info(tsk); |
| 173 | if (!ti) { |
| 174 | free_task_struct(tsk); |
| 175 | return NULL; |
| 176 | } |
| 177 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | *tsk = *orig; |
| 179 | tsk->thread_info = ti; |
Al Viro | 10ebffd | 2005-11-13 16:06:56 -0800 | [diff] [blame] | 180 | setup_thread_stack(tsk, orig); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | |
Arjan van de Ven | 0a42540 | 2006-09-26 10:52:38 +0200 | [diff] [blame] | 182 | #ifdef CONFIG_CC_STACKPROTECTOR |
| 183 | tsk->stack_canary = get_random_int(); |
| 184 | #endif |
| 185 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
| 187 | atomic_set(&tsk->usage,2); |
Giancarlo Formicuccia | 4b5d37a | 2005-09-09 13:01:22 -0700 | [diff] [blame] | 188 | atomic_set(&tsk->fs_excl, 0); |
Alexey Dobriyan | 6c5c934 | 2006-09-29 01:59:40 -0700 | [diff] [blame] | 189 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 190 | tsk->btrace_seq = 0; |
Alexey Dobriyan | 6c5c934 | 2006-09-29 01:59:40 -0700 | [diff] [blame] | 191 | #endif |
Jens Axboe | a0aa7f6 | 2006-04-20 13:05:33 +0200 | [diff] [blame] | 192 | tsk->splice_pipe = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | return tsk; |
| 194 | } |
| 195 | |
| 196 | #ifdef CONFIG_MMU |
Hugh Dickins | fd3e42f | 2005-10-29 18:16:06 -0700 | [diff] [blame] | 197 | static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | { |
Hugh Dickins | fd3e42f | 2005-10-29 18:16:06 -0700 | [diff] [blame] | 199 | struct vm_area_struct *mpnt, *tmp, **pprev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | struct rb_node **rb_link, *rb_parent; |
| 201 | int retval; |
| 202 | unsigned long charge; |
| 203 | struct mempolicy *pol; |
| 204 | |
| 205 | down_write(&oldmm->mmap_sem); |
Ralf Baechle | ec8c044 | 2006-12-12 17:14:57 +0000 | [diff] [blame] | 206 | flush_cache_dup_mm(oldmm); |
Ingo Molnar | ad33945 | 2006-07-03 00:25:15 -0700 | [diff] [blame] | 207 | /* |
| 208 | * Not linked in yet - no deadlock potential: |
| 209 | */ |
| 210 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); |
Hugh Dickins | 7ee7823 | 2005-10-29 18:16:08 -0700 | [diff] [blame] | 211 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | mm->locked_vm = 0; |
| 213 | mm->mmap = NULL; |
| 214 | mm->mmap_cache = NULL; |
| 215 | mm->free_area_cache = oldmm->mmap_base; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 216 | mm->cached_hole_size = ~0UL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | mm->map_count = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | cpus_clear(mm->cpu_vm_mask); |
| 219 | mm->mm_rb = RB_ROOT; |
| 220 | rb_link = &mm->mm_rb.rb_node; |
| 221 | rb_parent = NULL; |
| 222 | pprev = &mm->mmap; |
| 223 | |
Hugh Dickins | fd3e42f | 2005-10-29 18:16:06 -0700 | [diff] [blame] | 224 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | struct file *file; |
| 226 | |
| 227 | if (mpnt->vm_flags & VM_DONTCOPY) { |
Hugh Dickins | 3b6bfcd | 2005-07-12 13:58:09 -0700 | [diff] [blame] | 228 | long pages = vma_pages(mpnt); |
| 229 | mm->total_vm -= pages; |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 230 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
Hugh Dickins | 3b6bfcd | 2005-07-12 13:58:09 -0700 | [diff] [blame] | 231 | -pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | continue; |
| 233 | } |
| 234 | charge = 0; |
| 235 | if (mpnt->vm_flags & VM_ACCOUNT) { |
| 236 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; |
| 237 | if (security_vm_enough_memory(len)) |
| 238 | goto fail_nomem; |
| 239 | charge = len; |
| 240 | } |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 241 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | if (!tmp) |
| 243 | goto fail_nomem; |
| 244 | *tmp = *mpnt; |
| 245 | pol = mpol_copy(vma_policy(mpnt)); |
| 246 | retval = PTR_ERR(pol); |
| 247 | if (IS_ERR(pol)) |
| 248 | goto fail_nomem_policy; |
| 249 | vma_set_policy(tmp, pol); |
| 250 | tmp->vm_flags &= ~VM_LOCKED; |
| 251 | tmp->vm_mm = mm; |
| 252 | tmp->vm_next = NULL; |
| 253 | anon_vma_link(tmp); |
| 254 | file = tmp->vm_file; |
| 255 | if (file) { |
Josef "Jeff" Sipek | f3a43f3 | 2006-12-08 02:36:43 -0800 | [diff] [blame] | 256 | struct inode *inode = file->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | get_file(file); |
| 258 | if (tmp->vm_flags & VM_DENYWRITE) |
| 259 | atomic_dec(&inode->i_writecount); |
| 260 | |
| 261 | /* insert tmp into the share list, just after mpnt */ |
| 262 | spin_lock(&file->f_mapping->i_mmap_lock); |
| 263 | tmp->vm_truncate_count = mpnt->vm_truncate_count; |
| 264 | flush_dcache_mmap_lock(file->f_mapping); |
| 265 | vma_prio_tree_add(tmp, mpnt); |
| 266 | flush_dcache_mmap_unlock(file->f_mapping); |
| 267 | spin_unlock(&file->f_mapping->i_mmap_lock); |
| 268 | } |
| 269 | |
| 270 | /* |
Hugh Dickins | 7ee7823 | 2005-10-29 18:16:08 -0700 | [diff] [blame] | 271 | * Link in the new vma and copy the page table entries. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | *pprev = tmp; |
| 274 | pprev = &tmp->vm_next; |
| 275 | |
| 276 | __vma_link_rb(mm, tmp, rb_link, rb_parent); |
| 277 | rb_link = &tmp->vm_rb.rb_right; |
| 278 | rb_parent = &tmp->vm_rb; |
| 279 | |
| 280 | mm->map_count++; |
Hugh Dickins | 0b0db14 | 2005-11-21 21:32:20 -0800 | [diff] [blame] | 281 | retval = copy_page_range(mm, oldmm, mpnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | |
| 283 | if (tmp->vm_ops && tmp->vm_ops->open) |
| 284 | tmp->vm_ops->open(tmp); |
| 285 | |
| 286 | if (retval) |
| 287 | goto out; |
| 288 | } |
| 289 | retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | out: |
Hugh Dickins | 7ee7823 | 2005-10-29 18:16:08 -0700 | [diff] [blame] | 291 | up_write(&mm->mmap_sem); |
Hugh Dickins | fd3e42f | 2005-10-29 18:16:06 -0700 | [diff] [blame] | 292 | flush_tlb_mm(oldmm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | up_write(&oldmm->mmap_sem); |
| 294 | return retval; |
| 295 | fail_nomem_policy: |
| 296 | kmem_cache_free(vm_area_cachep, tmp); |
| 297 | fail_nomem: |
| 298 | retval = -ENOMEM; |
| 299 | vm_unacct_memory(charge); |
| 300 | goto out; |
| 301 | } |
| 302 | |
| 303 | static inline int mm_alloc_pgd(struct mm_struct * mm) |
| 304 | { |
| 305 | mm->pgd = pgd_alloc(mm); |
| 306 | if (unlikely(!mm->pgd)) |
| 307 | return -ENOMEM; |
| 308 | return 0; |
| 309 | } |
| 310 | |
| 311 | static inline void mm_free_pgd(struct mm_struct * mm) |
| 312 | { |
| 313 | pgd_free(mm->pgd); |
| 314 | } |
| 315 | #else |
| 316 | #define dup_mmap(mm, oldmm) (0) |
| 317 | #define mm_alloc_pgd(mm) (0) |
| 318 | #define mm_free_pgd(mm) |
| 319 | #endif /* CONFIG_MMU */ |
| 320 | |
| 321 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
| 322 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 323 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
| 325 | |
| 326 | #include <linux/init_task.h> |
| 327 | |
| 328 | static struct mm_struct * mm_init(struct mm_struct * mm) |
| 329 | { |
| 330 | atomic_set(&mm->mm_users, 1); |
| 331 | atomic_set(&mm->mm_count, 1); |
| 332 | init_rwsem(&mm->mmap_sem); |
| 333 | INIT_LIST_HEAD(&mm->mmlist); |
| 334 | mm->core_waiters = 0; |
| 335 | mm->nr_ptes = 0; |
Hugh Dickins | 4294621 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 336 | set_mm_counter(mm, file_rss, 0); |
Hugh Dickins | 404351e | 2005-10-29 18:16:04 -0700 | [diff] [blame] | 337 | set_mm_counter(mm, anon_rss, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | spin_lock_init(&mm->page_table_lock); |
| 339 | rwlock_init(&mm->ioctx_list_lock); |
| 340 | mm->ioctx_list = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 342 | mm->cached_hole_size = ~0UL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | |
| 344 | if (likely(!mm_alloc_pgd(mm))) { |
| 345 | mm->def_flags = 0; |
| 346 | return mm; |
| 347 | } |
| 348 | free_mm(mm); |
| 349 | return NULL; |
| 350 | } |
| 351 | |
| 352 | /* |
| 353 | * Allocate and initialize an mm_struct. |
| 354 | */ |
| 355 | struct mm_struct * mm_alloc(void) |
| 356 | { |
| 357 | struct mm_struct * mm; |
| 358 | |
| 359 | mm = allocate_mm(); |
| 360 | if (mm) { |
| 361 | memset(mm, 0, sizeof(*mm)); |
| 362 | mm = mm_init(mm); |
| 363 | } |
| 364 | return mm; |
| 365 | } |
| 366 | |
| 367 | /* |
| 368 | * Called when the last reference to the mm |
| 369 | * is dropped: either by a lazy thread or by |
| 370 | * mmput. Free the page directory and the mm. |
| 371 | */ |
| 372 | void fastcall __mmdrop(struct mm_struct *mm) |
| 373 | { |
| 374 | BUG_ON(mm == &init_mm); |
| 375 | mm_free_pgd(mm); |
| 376 | destroy_context(mm); |
| 377 | free_mm(mm); |
| 378 | } |
| 379 | |
| 380 | /* |
| 381 | * Decrement the use count and release all resources for an mm. |
| 382 | */ |
| 383 | void mmput(struct mm_struct *mm) |
| 384 | { |
Andrew Morton | 0ae26f1 | 2006-06-23 02:05:15 -0700 | [diff] [blame] | 385 | might_sleep(); |
| 386 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | if (atomic_dec_and_test(&mm->mm_users)) { |
| 388 | exit_aio(mm); |
| 389 | exit_mmap(mm); |
| 390 | if (!list_empty(&mm->mmlist)) { |
| 391 | spin_lock(&mmlist_lock); |
| 392 | list_del(&mm->mmlist); |
| 393 | spin_unlock(&mmlist_lock); |
| 394 | } |
| 395 | put_swap_token(mm); |
| 396 | mmdrop(mm); |
| 397 | } |
| 398 | } |
| 399 | EXPORT_SYMBOL_GPL(mmput); |
| 400 | |
| 401 | /** |
| 402 | * get_task_mm - acquire a reference to the task's mm |
| 403 | * |
| 404 | * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning |
| 405 | * this kernel workthread has transiently adopted a user mm with use_mm, |
| 406 | * to do its AIO) is not set and if so returns a reference to it, after |
| 407 | * bumping up the use count. User must release the mm via mmput() |
| 408 | * after use. Typically used by /proc and ptrace. |
| 409 | */ |
| 410 | struct mm_struct *get_task_mm(struct task_struct *task) |
| 411 | { |
| 412 | struct mm_struct *mm; |
| 413 | |
| 414 | task_lock(task); |
| 415 | mm = task->mm; |
| 416 | if (mm) { |
| 417 | if (task->flags & PF_BORROWED_MM) |
| 418 | mm = NULL; |
| 419 | else |
| 420 | atomic_inc(&mm->mm_users); |
| 421 | } |
| 422 | task_unlock(task); |
| 423 | return mm; |
| 424 | } |
| 425 | EXPORT_SYMBOL_GPL(get_task_mm); |
| 426 | |
| 427 | /* Please note the differences between mmput and mm_release. |
| 428 | * mmput is called whenever we stop holding onto a mm_struct, |
| 429 | * error success whatever. |
| 430 | * |
| 431 | * mm_release is called after a mm_struct has been removed |
| 432 | * from the current process. |
| 433 | * |
| 434 | * This difference is important for error handling, when we |
| 435 | * only half set up a mm_struct for a new process and need to restore |
| 436 | * the old one. Because we mmput the new mm_struct before |
| 437 | * restoring the old one. . . |
| 438 | * Eric Biederman 10 January 1998 |
| 439 | */ |
| 440 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) |
| 441 | { |
| 442 | struct completion *vfork_done = tsk->vfork_done; |
| 443 | |
| 444 | /* Get rid of any cached register state */ |
| 445 | deactivate_mm(tsk, mm); |
| 446 | |
| 447 | /* notify parent sleeping on vfork() */ |
| 448 | if (vfork_done) { |
| 449 | tsk->vfork_done = NULL; |
| 450 | complete(vfork_done); |
| 451 | } |
Roland McGrath | fec1d01 | 2006-12-06 20:36:34 -0800 | [diff] [blame] | 452 | |
| 453 | /* |
| 454 | * If we're exiting normally, clear a user-space tid field if |
| 455 | * requested. We leave this alone when dying by signal, to leave |
| 456 | * the value intact in a core dump, and to save the unnecessary |
| 457 | * trouble otherwise. Userland only wants this done for a sys_exit. |
| 458 | */ |
| 459 | if (tsk->clear_child_tid |
| 460 | && !(tsk->flags & PF_SIGNALED) |
| 461 | && atomic_read(&mm->mm_users) > 1) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | u32 __user * tidptr = tsk->clear_child_tid; |
| 463 | tsk->clear_child_tid = NULL; |
| 464 | |
| 465 | /* |
| 466 | * We don't check the error code - if userspace has |
| 467 | * not set up a proper pointer then tough luck. |
| 468 | */ |
| 469 | put_user(0, tidptr); |
| 470 | sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); |
| 471 | } |
| 472 | } |
| 473 | |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 474 | /* |
| 475 | * Allocate a new mm structure and copy contents from the |
| 476 | * mm structure of the passed in task structure. |
| 477 | */ |
| 478 | static struct mm_struct *dup_mm(struct task_struct *tsk) |
| 479 | { |
| 480 | struct mm_struct *mm, *oldmm = current->mm; |
| 481 | int err; |
| 482 | |
| 483 | if (!oldmm) |
| 484 | return NULL; |
| 485 | |
| 486 | mm = allocate_mm(); |
| 487 | if (!mm) |
| 488 | goto fail_nomem; |
| 489 | |
| 490 | memcpy(mm, oldmm, sizeof(*mm)); |
| 491 | |
Ashwin Chaugule | 7602bdf | 2006-12-06 20:31:57 -0800 | [diff] [blame] | 492 | /* Initializing for Swap token stuff */ |
| 493 | mm->token_priority = 0; |
| 494 | mm->last_interval = 0; |
| 495 | |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 496 | if (!mm_init(mm)) |
| 497 | goto fail_nomem; |
| 498 | |
| 499 | if (init_new_context(tsk, mm)) |
| 500 | goto fail_nocontext; |
| 501 | |
| 502 | err = dup_mmap(mm, oldmm); |
| 503 | if (err) |
| 504 | goto free_pt; |
| 505 | |
| 506 | mm->hiwater_rss = get_mm_rss(mm); |
| 507 | mm->hiwater_vm = mm->total_vm; |
| 508 | |
| 509 | return mm; |
| 510 | |
| 511 | free_pt: |
| 512 | mmput(mm); |
| 513 | |
| 514 | fail_nomem: |
| 515 | return NULL; |
| 516 | |
| 517 | fail_nocontext: |
| 518 | /* |
| 519 | * If init_new_context() failed, we cannot use mmput() to free the mm |
| 520 | * because it calls destroy_context() |
| 521 | */ |
| 522 | mm_free_pgd(mm); |
| 523 | free_mm(mm); |
| 524 | return NULL; |
| 525 | } |
| 526 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
| 528 | { |
| 529 | struct mm_struct * mm, *oldmm; |
| 530 | int retval; |
| 531 | |
| 532 | tsk->min_flt = tsk->maj_flt = 0; |
| 533 | tsk->nvcsw = tsk->nivcsw = 0; |
| 534 | |
| 535 | tsk->mm = NULL; |
| 536 | tsk->active_mm = NULL; |
| 537 | |
| 538 | /* |
| 539 | * Are we cloning a kernel thread? |
| 540 | * |
| 541 | * We need to steal a active VM for that.. |
| 542 | */ |
| 543 | oldmm = current->mm; |
| 544 | if (!oldmm) |
| 545 | return 0; |
| 546 | |
| 547 | if (clone_flags & CLONE_VM) { |
| 548 | atomic_inc(&oldmm->mm_users); |
| 549 | mm = oldmm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | goto good_mm; |
| 551 | } |
| 552 | |
| 553 | retval = -ENOMEM; |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 554 | mm = dup_mm(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | if (!mm) |
| 556 | goto fail_nomem; |
| 557 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | good_mm: |
Ashwin Chaugule | 7602bdf | 2006-12-06 20:31:57 -0800 | [diff] [blame] | 559 | /* Initializing for Swap token stuff */ |
| 560 | mm->token_priority = 0; |
| 561 | mm->last_interval = 0; |
| 562 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | tsk->mm = mm; |
| 564 | tsk->active_mm = mm; |
| 565 | return 0; |
| 566 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | fail_nomem: |
| 568 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | } |
| 570 | |
| 571 | static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old) |
| 572 | { |
| 573 | struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); |
| 574 | /* We don't need to lock fs - think why ;-) */ |
| 575 | if (fs) { |
| 576 | atomic_set(&fs->count, 1); |
| 577 | rwlock_init(&fs->lock); |
| 578 | fs->umask = old->umask; |
| 579 | read_lock(&old->lock); |
| 580 | fs->rootmnt = mntget(old->rootmnt); |
| 581 | fs->root = dget(old->root); |
| 582 | fs->pwdmnt = mntget(old->pwdmnt); |
| 583 | fs->pwd = dget(old->pwd); |
| 584 | if (old->altroot) { |
| 585 | fs->altrootmnt = mntget(old->altrootmnt); |
| 586 | fs->altroot = dget(old->altroot); |
| 587 | } else { |
| 588 | fs->altrootmnt = NULL; |
| 589 | fs->altroot = NULL; |
| 590 | } |
| 591 | read_unlock(&old->lock); |
| 592 | } |
| 593 | return fs; |
| 594 | } |
| 595 | |
| 596 | struct fs_struct *copy_fs_struct(struct fs_struct *old) |
| 597 | { |
| 598 | return __copy_fs_struct(old); |
| 599 | } |
| 600 | |
| 601 | EXPORT_SYMBOL_GPL(copy_fs_struct); |
| 602 | |
| 603 | static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk) |
| 604 | { |
| 605 | if (clone_flags & CLONE_FS) { |
| 606 | atomic_inc(¤t->fs->count); |
| 607 | return 0; |
| 608 | } |
| 609 | tsk->fs = __copy_fs_struct(current->fs); |
| 610 | if (!tsk->fs) |
| 611 | return -ENOMEM; |
| 612 | return 0; |
| 613 | } |
| 614 | |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 615 | static int count_open_files(struct fdtable *fdt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | { |
Vadim Lobanov | bbea9f6 | 2006-12-10 02:21:12 -0800 | [diff] [blame] | 617 | int size = fdt->max_fds; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 618 | int i; |
| 619 | |
| 620 | /* Find the last open fd */ |
| 621 | for (i = size/(8*sizeof(long)); i > 0; ) { |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 622 | if (fdt->open_fds->fds_bits[--i]) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | break; |
| 624 | } |
| 625 | i = (i+1) * 8 * sizeof(long); |
| 626 | return i; |
| 627 | } |
| 628 | |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 629 | static struct files_struct *alloc_files(void) |
| 630 | { |
| 631 | struct files_struct *newf; |
| 632 | struct fdtable *fdt; |
| 633 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 634 | newf = kmem_cache_alloc(files_cachep, GFP_KERNEL); |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 635 | if (!newf) |
| 636 | goto out; |
| 637 | |
| 638 | atomic_set(&newf->count, 1); |
| 639 | |
| 640 | spin_lock_init(&newf->file_lock); |
Eric Dumazet | 0c9e63f | 2006-03-23 03:00:12 -0800 | [diff] [blame] | 641 | newf->next_fd = 0; |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 642 | fdt = &newf->fdtab; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 643 | fdt->max_fds = NR_OPEN_DEFAULT; |
Eric Dumazet | 0c9e63f | 2006-03-23 03:00:12 -0800 | [diff] [blame] | 644 | fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init; |
| 645 | fdt->open_fds = (fd_set *)&newf->open_fds_init; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 646 | fdt->fd = &newf->fd_array[0]; |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 647 | INIT_RCU_HEAD(&fdt->rcu); |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 648 | fdt->next = NULL; |
| 649 | rcu_assign_pointer(newf->fdt, fdt); |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 650 | out: |
| 651 | return newf; |
| 652 | } |
| 653 | |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 654 | /* |
| 655 | * Allocate a new files structure and copy contents from the |
| 656 | * passed in files structure. |
Prasanna Meda | 6e66726 | 2006-06-23 02:05:23 -0700 | [diff] [blame] | 657 | * errorp will be valid only when the returned files_struct is NULL. |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 658 | */ |
| 659 | static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | { |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 661 | struct files_struct *newf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | struct file **old_fds, **new_fds; |
Vadim Lobanov | bbea9f6 | 2006-12-10 02:21:12 -0800 | [diff] [blame] | 663 | int open_files, size, i; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 664 | struct fdtable *old_fdt, *new_fdt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | |
Prasanna Meda | 6e66726 | 2006-06-23 02:05:23 -0700 | [diff] [blame] | 666 | *errorp = -ENOMEM; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 667 | newf = alloc_files(); |
| 668 | if (!newf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | goto out; |
| 670 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | spin_lock(&oldf->file_lock); |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 672 | old_fdt = files_fdtable(oldf); |
| 673 | new_fdt = files_fdtable(newf); |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 674 | open_files = count_open_files(old_fdt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | |
| 676 | /* |
Vadim Lobanov | bbea9f6 | 2006-12-10 02:21:12 -0800 | [diff] [blame] | 677 | * Check whether we need to allocate a larger fd array and fd set. |
| 678 | * Note: we're not a clone task, so the open count won't change. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | */ |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 680 | if (open_files > new_fdt->max_fds) { |
| 681 | new_fdt->max_fds = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 682 | spin_unlock(&oldf->file_lock); |
| 683 | spin_lock(&newf->file_lock); |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 684 | *errorp = expand_files(newf, open_files-1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | spin_unlock(&newf->file_lock); |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 686 | if (*errorp < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | goto out_release; |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 688 | new_fdt = files_fdtable(newf); |
| 689 | /* |
| 690 | * Reacquire the oldf lock and a pointer to its fd table |
| 691 | * who knows it may have a new bigger fd table. We need |
| 692 | * the latest pointer. |
| 693 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | spin_lock(&oldf->file_lock); |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 695 | old_fdt = files_fdtable(oldf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 696 | } |
| 697 | |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 698 | old_fds = old_fdt->fd; |
| 699 | new_fds = new_fdt->fd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | |
Vadim Lobanov | f3d19c9 | 2006-12-10 02:21:09 -0800 | [diff] [blame] | 701 | memcpy(new_fdt->open_fds->fds_bits, |
| 702 | old_fdt->open_fds->fds_bits, open_files/8); |
| 703 | memcpy(new_fdt->close_on_exec->fds_bits, |
| 704 | old_fdt->close_on_exec->fds_bits, open_files/8); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 705 | |
| 706 | for (i = open_files; i != 0; i--) { |
| 707 | struct file *f = *old_fds++; |
| 708 | if (f) { |
| 709 | get_file(f); |
| 710 | } else { |
| 711 | /* |
| 712 | * The fd may be claimed in the fd bitmap but not yet |
| 713 | * instantiated in the files array if a sibling thread |
| 714 | * is partway through open(). So make sure that this |
| 715 | * fd is available to the new process. |
| 716 | */ |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 717 | FD_CLR(open_files - i, new_fdt->open_fds); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 718 | } |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 719 | rcu_assign_pointer(*new_fds++, f); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | } |
| 721 | spin_unlock(&oldf->file_lock); |
| 722 | |
| 723 | /* compute the remainder to be cleared */ |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 724 | size = (new_fdt->max_fds - open_files) * sizeof(struct file *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | |
| 726 | /* This is long word aligned thus could use a optimized version */ |
| 727 | memset(new_fds, 0, size); |
| 728 | |
Vadim Lobanov | bbea9f6 | 2006-12-10 02:21:12 -0800 | [diff] [blame] | 729 | if (new_fdt->max_fds > open_files) { |
| 730 | int left = (new_fdt->max_fds-open_files)/8; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | int start = open_files / (8 * sizeof(unsigned long)); |
| 732 | |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 733 | memset(&new_fdt->open_fds->fds_bits[start], 0, left); |
| 734 | memset(&new_fdt->close_on_exec->fds_bits[start], 0, left); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | } |
| 736 | |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 737 | return newf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | |
| 739 | out_release: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | kmem_cache_free(files_cachep, newf); |
Vadim Lobanov | f3d19c9 | 2006-12-10 02:21:09 -0800 | [diff] [blame] | 741 | out: |
Kirill Korotaev | 4286229 | 2006-03-31 17:58:46 +0400 | [diff] [blame] | 742 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 743 | } |
| 744 | |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 745 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
| 746 | { |
| 747 | struct files_struct *oldf, *newf; |
| 748 | int error = 0; |
| 749 | |
| 750 | /* |
| 751 | * A background process may not have any files ... |
| 752 | */ |
| 753 | oldf = current->files; |
| 754 | if (!oldf) |
| 755 | goto out; |
| 756 | |
| 757 | if (clone_flags & CLONE_FILES) { |
| 758 | atomic_inc(&oldf->count); |
| 759 | goto out; |
| 760 | } |
| 761 | |
| 762 | /* |
| 763 | * Note: we may be using current for both targets (See exec.c) |
| 764 | * This works because we cache current->files (old) as oldf. Don't |
| 765 | * break this. |
| 766 | */ |
| 767 | tsk->files = NULL; |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 768 | newf = dup_fd(oldf, &error); |
| 769 | if (!newf) |
| 770 | goto out; |
| 771 | |
| 772 | tsk->files = newf; |
| 773 | error = 0; |
| 774 | out: |
| 775 | return error; |
| 776 | } |
| 777 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | /* |
| 779 | * Helper to unshare the files of the current task. |
| 780 | * We don't want to expose copy_files internals to |
| 781 | * the exec layer of the kernel. |
| 782 | */ |
| 783 | |
| 784 | int unshare_files(void) |
| 785 | { |
| 786 | struct files_struct *files = current->files; |
| 787 | int rc; |
| 788 | |
Eric Sesterhenn | 910dea7 | 2006-03-26 18:29:26 +0200 | [diff] [blame] | 789 | BUG_ON(!files); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 790 | |
| 791 | /* This can race but the race causes us to copy when we don't |
| 792 | need to and drop the copy */ |
| 793 | if(atomic_read(&files->count) == 1) |
| 794 | { |
| 795 | atomic_inc(&files->count); |
| 796 | return 0; |
| 797 | } |
| 798 | rc = copy_files(0, current); |
| 799 | if(rc) |
| 800 | current->files = files; |
| 801 | return rc; |
| 802 | } |
| 803 | |
| 804 | EXPORT_SYMBOL(unshare_files); |
| 805 | |
| 806 | static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk) |
| 807 | { |
| 808 | struct sighand_struct *sig; |
| 809 | |
| 810 | if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) { |
| 811 | atomic_inc(¤t->sighand->count); |
| 812 | return 0; |
| 813 | } |
| 814 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
Ingo Molnar | e56d090 | 2006-01-08 01:01:37 -0800 | [diff] [blame] | 815 | rcu_assign_pointer(tsk->sighand, sig); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 816 | if (!sig) |
| 817 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 818 | atomic_set(&sig->count, 1); |
| 819 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); |
| 820 | return 0; |
| 821 | } |
| 822 | |
Oleg Nesterov | a7e5328 | 2006-03-28 16:11:27 -0800 | [diff] [blame] | 823 | void __cleanup_sighand(struct sighand_struct *sighand) |
Oleg Nesterov | c81addc | 2006-03-28 16:11:17 -0800 | [diff] [blame] | 824 | { |
Oleg Nesterov | c81addc | 2006-03-28 16:11:17 -0800 | [diff] [blame] | 825 | if (atomic_dec_and_test(&sighand->count)) |
| 826 | kmem_cache_free(sighand_cachep, sighand); |
| 827 | } |
| 828 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk) |
| 830 | { |
| 831 | struct signal_struct *sig; |
| 832 | int ret; |
| 833 | |
| 834 | if (clone_flags & CLONE_THREAD) { |
| 835 | atomic_inc(¤t->signal->count); |
| 836 | atomic_inc(¤t->signal->live); |
| 837 | return 0; |
| 838 | } |
| 839 | sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL); |
| 840 | tsk->signal = sig; |
| 841 | if (!sig) |
| 842 | return -ENOMEM; |
| 843 | |
| 844 | ret = copy_thread_group_keys(tsk); |
| 845 | if (ret < 0) { |
| 846 | kmem_cache_free(signal_cachep, sig); |
| 847 | return ret; |
| 848 | } |
| 849 | |
| 850 | atomic_set(&sig->count, 1); |
| 851 | atomic_set(&sig->live, 1); |
| 852 | init_waitqueue_head(&sig->wait_chldexit); |
| 853 | sig->flags = 0; |
| 854 | sig->group_exit_code = 0; |
| 855 | sig->group_exit_task = NULL; |
| 856 | sig->group_stop_count = 0; |
| 857 | sig->curr_target = NULL; |
| 858 | init_sigpending(&sig->shared_pending); |
| 859 | INIT_LIST_HEAD(&sig->posix_timers); |
| 860 | |
George Anzinger | 7978672 | 2006-02-01 03:05:11 -0800 | [diff] [blame] | 861 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL); |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 862 | sig->it_real_incr.tv64 = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | sig->real_timer.function = it_real_fn; |
Roman Zippel | 05cfb61 | 2006-03-26 01:38:12 -0800 | [diff] [blame] | 864 | sig->tsk = tsk; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 865 | |
| 866 | sig->it_virt_expires = cputime_zero; |
| 867 | sig->it_virt_incr = cputime_zero; |
| 868 | sig->it_prof_expires = cputime_zero; |
| 869 | sig->it_prof_incr = cputime_zero; |
| 870 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 871 | sig->leader = 0; /* session leadership doesn't inherit */ |
Eric W. Biederman | ab521dc | 2007-02-12 00:53:00 -0800 | [diff] [blame] | 872 | sig->tty_old_pgrp = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | |
| 874 | sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; |
| 875 | sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0; |
| 876 | sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0; |
| 877 | sig->sched_time = 0; |
| 878 | INIT_LIST_HEAD(&sig->cpu_timers[0]); |
| 879 | INIT_LIST_HEAD(&sig->cpu_timers[1]); |
| 880 | INIT_LIST_HEAD(&sig->cpu_timers[2]); |
Shailabh Nagar | ad4ecbc | 2006-07-14 00:24:44 -0700 | [diff] [blame] | 881 | taskstats_tgid_init(sig); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 882 | |
| 883 | task_lock(current->group_leader); |
| 884 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); |
| 885 | task_unlock(current->group_leader); |
| 886 | |
| 887 | if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) { |
| 888 | /* |
| 889 | * New sole thread in the process gets an expiry time |
| 890 | * of the whole CPU time limit. |
| 891 | */ |
| 892 | tsk->it_prof_expires = |
| 893 | secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur); |
| 894 | } |
KaiGai Kohei | 0e46481 | 2006-06-25 05:49:24 -0700 | [diff] [blame] | 895 | acct_init_pacct(&sig->pacct); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 896 | |
| 897 | return 0; |
| 898 | } |
| 899 | |
Oleg Nesterov | 6b3934e | 2006-03-28 16:11:16 -0800 | [diff] [blame] | 900 | void __cleanup_signal(struct signal_struct *sig) |
| 901 | { |
| 902 | exit_thread_group_keys(sig); |
| 903 | kmem_cache_free(signal_cachep, sig); |
| 904 | } |
| 905 | |
| 906 | static inline void cleanup_signal(struct task_struct *tsk) |
| 907 | { |
| 908 | struct signal_struct *sig = tsk->signal; |
| 909 | |
| 910 | atomic_dec(&sig->live); |
| 911 | |
| 912 | if (atomic_dec_and_test(&sig->count)) |
| 913 | __cleanup_signal(sig); |
| 914 | } |
| 915 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | static inline void copy_flags(unsigned long clone_flags, struct task_struct *p) |
| 917 | { |
| 918 | unsigned long new_flags = p->flags; |
| 919 | |
Alan Stern | d1209d0 | 2005-10-19 21:23:51 -0700 | [diff] [blame] | 920 | new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 921 | new_flags |= PF_FORKNOEXEC; |
| 922 | if (!(clone_flags & CLONE_PTRACE)) |
| 923 | p->ptrace = 0; |
| 924 | p->flags = new_flags; |
| 925 | } |
| 926 | |
| 927 | asmlinkage long sys_set_tid_address(int __user *tidptr) |
| 928 | { |
| 929 | current->clear_child_tid = tidptr; |
| 930 | |
| 931 | return current->pid; |
| 932 | } |
| 933 | |
Ingo Molnar | 23f78d4 | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 934 | static inline void rt_mutex_init_task(struct task_struct *p) |
| 935 | { |
| 936 | #ifdef CONFIG_RT_MUTEXES |
| 937 | spin_lock_init(&p->pi_lock); |
| 938 | plist_head_init(&p->pi_waiters, &p->pi_lock); |
| 939 | p->pi_blocked_on = NULL; |
Ingo Molnar | 23f78d4 | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 940 | #endif |
| 941 | } |
| 942 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 943 | /* |
| 944 | * This creates a new process as a copy of the old one, |
| 945 | * but does not actually start it yet. |
| 946 | * |
| 947 | * It copies the registers, and all the appropriate |
| 948 | * parts of the process environment (as per the clone |
| 949 | * flags). The actual kick-off is left to the caller. |
| 950 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 951 | static struct task_struct *copy_process(unsigned long clone_flags, |
| 952 | unsigned long stack_start, |
| 953 | struct pt_regs *regs, |
| 954 | unsigned long stack_size, |
| 955 | int __user *parent_tidptr, |
| 956 | int __user *child_tidptr, |
| 957 | int pid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 958 | { |
| 959 | int retval; |
| 960 | struct task_struct *p = NULL; |
| 961 | |
| 962 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) |
| 963 | return ERR_PTR(-EINVAL); |
| 964 | |
| 965 | /* |
| 966 | * Thread groups must share signals as well, and detached threads |
| 967 | * can only be started up within the thread group. |
| 968 | */ |
| 969 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) |
| 970 | return ERR_PTR(-EINVAL); |
| 971 | |
| 972 | /* |
| 973 | * Shared signal handlers imply shared VM. By way of the above, |
| 974 | * thread groups also imply shared VM. Blocking this case allows |
| 975 | * for various simplifications in other code. |
| 976 | */ |
| 977 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) |
| 978 | return ERR_PTR(-EINVAL); |
| 979 | |
| 980 | retval = security_task_create(clone_flags); |
| 981 | if (retval) |
| 982 | goto fork_out; |
| 983 | |
| 984 | retval = -ENOMEM; |
| 985 | p = dup_task_struct(current); |
| 986 | if (!p) |
| 987 | goto fork_out; |
| 988 | |
Peter Zijlstra | bea493a | 2006-10-17 00:10:33 -0700 | [diff] [blame] | 989 | rt_mutex_init_task(p); |
| 990 | |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 991 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 992 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
| 993 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); |
| 994 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 995 | retval = -EAGAIN; |
| 996 | if (atomic_read(&p->user->processes) >= |
| 997 | p->signal->rlim[RLIMIT_NPROC].rlim_cur) { |
| 998 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && |
| 999 | p->user != &root_user) |
| 1000 | goto bad_fork_free; |
| 1001 | } |
| 1002 | |
| 1003 | atomic_inc(&p->user->__count); |
| 1004 | atomic_inc(&p->user->processes); |
| 1005 | get_group_info(p->group_info); |
| 1006 | |
| 1007 | /* |
| 1008 | * If multiple threads are within copy_process(), then this check |
| 1009 | * triggers too late. This doesn't hurt, the check is only there |
| 1010 | * to stop root fork bombs. |
| 1011 | */ |
| 1012 | if (nr_threads >= max_threads) |
| 1013 | goto bad_fork_cleanup_count; |
| 1014 | |
Al Viro | a1261f5 | 2005-11-13 16:06:55 -0800 | [diff] [blame] | 1015 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1016 | goto bad_fork_cleanup_count; |
| 1017 | |
| 1018 | if (p->binfmt && !try_module_get(p->binfmt->module)) |
| 1019 | goto bad_fork_cleanup_put_domain; |
| 1020 | |
| 1021 | p->did_exec = 0; |
Shailabh Nagar | ca74e92 | 2006-07-14 00:24:36 -0700 | [diff] [blame] | 1022 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1023 | copy_flags(clone_flags, p); |
| 1024 | p->pid = pid; |
| 1025 | retval = -EFAULT; |
| 1026 | if (clone_flags & CLONE_PARENT_SETTID) |
| 1027 | if (put_user(p->pid, parent_tidptr)) |
Shailabh Nagar | 35df17c | 2006-08-31 21:27:38 -0700 | [diff] [blame] | 1028 | goto bad_fork_cleanup_delays_binfmt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1029 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1030 | INIT_LIST_HEAD(&p->children); |
| 1031 | INIT_LIST_HEAD(&p->sibling); |
| 1032 | p->vfork_done = NULL; |
| 1033 | spin_lock_init(&p->alloc_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1034 | |
| 1035 | clear_tsk_thread_flag(p, TIF_SIGPENDING); |
| 1036 | init_sigpending(&p->pending); |
| 1037 | |
| 1038 | p->utime = cputime_zero; |
| 1039 | p->stime = cputime_zero; |
| 1040 | p->sched_time = 0; |
Alexey Dobriyan | 4b98d11 | 2007-02-10 01:46:45 -0800 | [diff] [blame] | 1041 | #ifdef CONFIG_TASK_XACCT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | p->rchar = 0; /* I/O counter: bytes read */ |
| 1043 | p->wchar = 0; /* I/O counter: bytes written */ |
| 1044 | p->syscr = 0; /* I/O counter: read syscalls */ |
| 1045 | p->syscw = 0; /* I/O counter: write syscalls */ |
Alexey Dobriyan | 4b98d11 | 2007-02-10 01:46:45 -0800 | [diff] [blame] | 1046 | #endif |
Andrew Morton | 7c3ab73 | 2006-12-10 02:19:19 -0800 | [diff] [blame] | 1047 | task_io_accounting_init(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1048 | acct_clear_integrals(p); |
| 1049 | |
| 1050 | p->it_virt_expires = cputime_zero; |
| 1051 | p->it_prof_expires = cputime_zero; |
| 1052 | p->it_sched_expires = 0; |
| 1053 | INIT_LIST_HEAD(&p->cpu_timers[0]); |
| 1054 | INIT_LIST_HEAD(&p->cpu_timers[1]); |
| 1055 | INIT_LIST_HEAD(&p->cpu_timers[2]); |
| 1056 | |
| 1057 | p->lock_depth = -1; /* -1 = no lock */ |
| 1058 | do_posix_clock_monotonic_gettime(&p->start_time); |
| 1059 | p->security = NULL; |
| 1060 | p->io_context = NULL; |
| 1061 | p->io_wait = NULL; |
| 1062 | p->audit_context = NULL; |
Paul Jackson | b4b2641 | 2006-01-08 01:01:53 -0800 | [diff] [blame] | 1063 | cpuset_fork(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1064 | #ifdef CONFIG_NUMA |
| 1065 | p->mempolicy = mpol_copy(p->mempolicy); |
| 1066 | if (IS_ERR(p->mempolicy)) { |
| 1067 | retval = PTR_ERR(p->mempolicy); |
| 1068 | p->mempolicy = NULL; |
Paul Jackson | b4b2641 | 2006-01-08 01:01:53 -0800 | [diff] [blame] | 1069 | goto bad_fork_cleanup_cpuset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | } |
Paul Jackson | c61afb1 | 2006-03-24 03:16:08 -0800 | [diff] [blame] | 1071 | mpol_fix_fork_child_flag(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | #endif |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 1073 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 1074 | p->irq_events = 0; |
Russell King | b36e475 | 2006-08-27 12:26:34 +0100 | [diff] [blame] | 1075 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
| 1076 | p->hardirqs_enabled = 1; |
| 1077 | #else |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 1078 | p->hardirqs_enabled = 0; |
Russell King | b36e475 | 2006-08-27 12:26:34 +0100 | [diff] [blame] | 1079 | #endif |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 1080 | p->hardirq_enable_ip = 0; |
| 1081 | p->hardirq_enable_event = 0; |
| 1082 | p->hardirq_disable_ip = _THIS_IP_; |
| 1083 | p->hardirq_disable_event = 0; |
| 1084 | p->softirqs_enabled = 1; |
| 1085 | p->softirq_enable_ip = _THIS_IP_; |
| 1086 | p->softirq_enable_event = 0; |
| 1087 | p->softirq_disable_ip = 0; |
| 1088 | p->softirq_disable_event = 0; |
| 1089 | p->hardirq_context = 0; |
| 1090 | p->softirq_context = 0; |
| 1091 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1092 | #ifdef CONFIG_LOCKDEP |
| 1093 | p->lockdep_depth = 0; /* no locks held yet */ |
| 1094 | p->curr_chain_key = 0; |
| 1095 | p->lockdep_recursion = 0; |
| 1096 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | |
Ingo Molnar | 408894e | 2006-01-09 15:59:20 -0800 | [diff] [blame] | 1098 | #ifdef CONFIG_DEBUG_MUTEXES |
| 1099 | p->blocked_on = NULL; /* not blocked yet */ |
| 1100 | #endif |
| 1101 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1102 | p->tgid = p->pid; |
| 1103 | if (clone_flags & CLONE_THREAD) |
| 1104 | p->tgid = current->tgid; |
| 1105 | |
| 1106 | if ((retval = security_task_alloc(p))) |
| 1107 | goto bad_fork_cleanup_policy; |
| 1108 | if ((retval = audit_alloc(p))) |
| 1109 | goto bad_fork_cleanup_security; |
| 1110 | /* copy all the process information */ |
| 1111 | if ((retval = copy_semundo(clone_flags, p))) |
| 1112 | goto bad_fork_cleanup_audit; |
| 1113 | if ((retval = copy_files(clone_flags, p))) |
| 1114 | goto bad_fork_cleanup_semundo; |
| 1115 | if ((retval = copy_fs(clone_flags, p))) |
| 1116 | goto bad_fork_cleanup_files; |
| 1117 | if ((retval = copy_sighand(clone_flags, p))) |
| 1118 | goto bad_fork_cleanup_fs; |
| 1119 | if ((retval = copy_signal(clone_flags, p))) |
| 1120 | goto bad_fork_cleanup_sighand; |
| 1121 | if ((retval = copy_mm(clone_flags, p))) |
| 1122 | goto bad_fork_cleanup_signal; |
| 1123 | if ((retval = copy_keys(clone_flags, p))) |
| 1124 | goto bad_fork_cleanup_mm; |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1125 | if ((retval = copy_namespaces(clone_flags, p))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | goto bad_fork_cleanup_keys; |
| 1127 | retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs); |
| 1128 | if (retval) |
Serge E. Hallyn | 1651e14 | 2006-10-02 02:18:08 -0700 | [diff] [blame] | 1129 | goto bad_fork_cleanup_namespaces; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | |
| 1131 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
| 1132 | /* |
| 1133 | * Clear TID on mm_release()? |
| 1134 | */ |
| 1135 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; |
Ingo Molnar | 8f17d3a | 2006-03-27 01:16:27 -0800 | [diff] [blame] | 1136 | p->robust_list = NULL; |
| 1137 | #ifdef CONFIG_COMPAT |
| 1138 | p->compat_robust_list = NULL; |
| 1139 | #endif |
Ingo Molnar | c87e283 | 2006-06-27 02:54:58 -0700 | [diff] [blame] | 1140 | INIT_LIST_HEAD(&p->pi_state_list); |
| 1141 | p->pi_state_cache = NULL; |
| 1142 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1143 | /* |
GOTO Masanori | f9a3879 | 2006-03-13 21:20:44 -0800 | [diff] [blame] | 1144 | * sigaltstack should be cleared when sharing the same VM |
| 1145 | */ |
| 1146 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) |
| 1147 | p->sas_ss_sp = p->sas_ss_size = 0; |
| 1148 | |
| 1149 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1150 | * Syscall tracing should be turned off in the child regardless |
| 1151 | * of CLONE_PTRACE. |
| 1152 | */ |
| 1153 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
Laurent Vivier | ed75e8d | 2005-09-03 15:57:18 -0700 | [diff] [blame] | 1154 | #ifdef TIF_SYSCALL_EMU |
| 1155 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); |
| 1156 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1157 | |
| 1158 | /* Our parent execution domain becomes current domain |
| 1159 | These must match for thread signalling to apply */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1160 | p->parent_exec_id = p->self_exec_id; |
| 1161 | |
| 1162 | /* ok, now we should be set up.. */ |
| 1163 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); |
| 1164 | p->pdeath_signal = 0; |
| 1165 | p->exit_state = 0; |
| 1166 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1167 | /* |
| 1168 | * Ok, make it visible to the rest of the system. |
| 1169 | * We dont wake it up yet. |
| 1170 | */ |
| 1171 | p->group_leader = p; |
Oleg Nesterov | 47e6532 | 2006-03-28 16:11:25 -0800 | [diff] [blame] | 1172 | INIT_LIST_HEAD(&p->thread_group); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1173 | INIT_LIST_HEAD(&p->ptrace_children); |
| 1174 | INIT_LIST_HEAD(&p->ptrace_list); |
| 1175 | |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1176 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
| 1177 | sched_fork(p, clone_flags); |
| 1178 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1179 | /* Need tasklist lock for parent etc handling! */ |
| 1180 | write_lock_irq(&tasklist_lock); |
| 1181 | |
Oleg Nesterov | 5b160f5 | 2006-09-29 02:00:52 -0700 | [diff] [blame] | 1182 | /* for sys_ioprio_set(IOPRIO_WHO_PGRP) */ |
| 1183 | p->ioprio = current->ioprio; |
| 1184 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1185 | /* |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1186 | * The task hasn't been attached yet, so its cpus_allowed mask will |
| 1187 | * not be changed, nor will its assigned CPU. |
| 1188 | * |
| 1189 | * The cpus_allowed mask of the parent may have changed after it was |
| 1190 | * copied first time - so re-copy it here, then check the child's CPU |
| 1191 | * to ensure it is on a valid CPU (and if not, just force it back to |
| 1192 | * parent's CPU). This avoids alot of nasty races. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1193 | */ |
| 1194 | p->cpus_allowed = current->cpus_allowed; |
Srivatsa Vaddagiri | 26ff6ad | 2005-09-16 19:27:40 -0700 | [diff] [blame] | 1195 | if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) || |
| 1196 | !cpu_online(task_cpu(p)))) |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1197 | set_task_cpu(p, smp_processor_id()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1198 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1199 | /* CLONE_PARENT re-uses the old parent */ |
| 1200 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) |
| 1201 | p->real_parent = current->real_parent; |
| 1202 | else |
| 1203 | p->real_parent = current; |
| 1204 | p->parent = p->real_parent; |
| 1205 | |
Oleg Nesterov | 3f17da6 | 2006-02-15 22:13:24 +0300 | [diff] [blame] | 1206 | spin_lock(¤t->sighand->siglock); |
Oleg Nesterov | 4a2c7a7 | 2006-03-28 16:11:26 -0800 | [diff] [blame] | 1207 | |
| 1208 | /* |
| 1209 | * Process group and session signals need to be delivered to just the |
| 1210 | * parent before the fork or both the parent and the child after the |
| 1211 | * fork. Restart if a signal comes in before we add the new process to |
| 1212 | * it's process group. |
| 1213 | * A fatal signal pending means that current will exit, so the new |
| 1214 | * thread can't slip out of an OOM kill (or normal SIGKILL). |
| 1215 | */ |
| 1216 | recalc_sigpending(); |
| 1217 | if (signal_pending(current)) { |
| 1218 | spin_unlock(¤t->sighand->siglock); |
| 1219 | write_unlock_irq(&tasklist_lock); |
| 1220 | retval = -ERESTARTNOINTR; |
Serge E. Hallyn | 1651e14 | 2006-10-02 02:18:08 -0700 | [diff] [blame] | 1221 | goto bad_fork_cleanup_namespaces; |
Oleg Nesterov | 4a2c7a7 | 2006-03-28 16:11:26 -0800 | [diff] [blame] | 1222 | } |
| 1223 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1224 | if (clone_flags & CLONE_THREAD) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1225 | p->group_leader = current->group_leader; |
Oleg Nesterov | 47e6532 | 2006-03-28 16:11:25 -0800 | [diff] [blame] | 1226 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1227 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1228 | if (!cputime_eq(current->signal->it_virt_expires, |
| 1229 | cputime_zero) || |
| 1230 | !cputime_eq(current->signal->it_prof_expires, |
| 1231 | cputime_zero) || |
| 1232 | current->signal->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY || |
| 1233 | !list_empty(¤t->signal->cpu_timers[0]) || |
| 1234 | !list_empty(¤t->signal->cpu_timers[1]) || |
| 1235 | !list_empty(¤t->signal->cpu_timers[2])) { |
| 1236 | /* |
| 1237 | * Have child wake up on its first tick to check |
| 1238 | * for process CPU timers. |
| 1239 | */ |
| 1240 | p->it_prof_expires = jiffies_to_cputime(1); |
| 1241 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1242 | } |
| 1243 | |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1244 | if (likely(p->pid)) { |
| 1245 | add_parent(p); |
| 1246 | if (unlikely(p->ptrace & PT_PTRACED)) |
| 1247 | __ptrace_link(p, current->parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1248 | |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1249 | if (thread_group_leader(p)) { |
| 1250 | p->signal->tty = current->signal->tty; |
| 1251 | p->signal->pgrp = process_group(current); |
Cedric Le Goater | 1ec320a | 2006-12-08 02:37:55 -0800 | [diff] [blame] | 1252 | set_signal_session(p->signal, process_session(current)); |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1253 | attach_pid(p, PIDTYPE_PGID, process_group(p)); |
Cedric Le Goater | 937949d | 2006-12-08 02:37:54 -0800 | [diff] [blame] | 1254 | attach_pid(p, PIDTYPE_SID, process_session(p)); |
Oleg Nesterov | c97d989 | 2006-03-28 16:11:06 -0800 | [diff] [blame] | 1255 | |
Eric W. Biederman | 5e85d4a | 2006-04-18 22:20:16 -0700 | [diff] [blame] | 1256 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1257 | __get_cpu_var(process_counts)++; |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1258 | } |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1259 | attach_pid(p, PIDTYPE_PID, p->pid); |
| 1260 | nr_threads++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1261 | } |
| 1262 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1263 | total_forks++; |
Oleg Nesterov | 3f17da6 | 2006-02-15 22:13:24 +0300 | [diff] [blame] | 1264 | spin_unlock(¤t->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1265 | write_unlock_irq(&tasklist_lock); |
Andrew Morton | c13cf85 | 2005-11-28 13:43:48 -0800 | [diff] [blame] | 1266 | proc_fork_connector(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1267 | return p; |
| 1268 | |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1269 | bad_fork_cleanup_namespaces: |
Linus Torvalds | 444f378 | 2007-01-30 13:35:18 -0800 | [diff] [blame] | 1270 | exit_task_namespaces(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1271 | bad_fork_cleanup_keys: |
| 1272 | exit_keys(p); |
| 1273 | bad_fork_cleanup_mm: |
| 1274 | if (p->mm) |
| 1275 | mmput(p->mm); |
| 1276 | bad_fork_cleanup_signal: |
Oleg Nesterov | 6b3934e | 2006-03-28 16:11:16 -0800 | [diff] [blame] | 1277 | cleanup_signal(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1278 | bad_fork_cleanup_sighand: |
Oleg Nesterov | a7e5328 | 2006-03-28 16:11:27 -0800 | [diff] [blame] | 1279 | __cleanup_sighand(p->sighand); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1280 | bad_fork_cleanup_fs: |
| 1281 | exit_fs(p); /* blocking */ |
| 1282 | bad_fork_cleanup_files: |
| 1283 | exit_files(p); /* blocking */ |
| 1284 | bad_fork_cleanup_semundo: |
| 1285 | exit_sem(p); |
| 1286 | bad_fork_cleanup_audit: |
| 1287 | audit_free(p); |
| 1288 | bad_fork_cleanup_security: |
| 1289 | security_task_free(p); |
| 1290 | bad_fork_cleanup_policy: |
| 1291 | #ifdef CONFIG_NUMA |
| 1292 | mpol_free(p->mempolicy); |
Paul Jackson | b4b2641 | 2006-01-08 01:01:53 -0800 | [diff] [blame] | 1293 | bad_fork_cleanup_cpuset: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1294 | #endif |
Paul Jackson | b4b2641 | 2006-01-08 01:01:53 -0800 | [diff] [blame] | 1295 | cpuset_exit(p); |
Shailabh Nagar | 35df17c | 2006-08-31 21:27:38 -0700 | [diff] [blame] | 1296 | bad_fork_cleanup_delays_binfmt: |
| 1297 | delayacct_tsk_free(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1298 | if (p->binfmt) |
| 1299 | module_put(p->binfmt->module); |
| 1300 | bad_fork_cleanup_put_domain: |
Al Viro | a1261f5 | 2005-11-13 16:06:55 -0800 | [diff] [blame] | 1301 | module_put(task_thread_info(p)->exec_domain->module); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1302 | bad_fork_cleanup_count: |
| 1303 | put_group_info(p->group_info); |
| 1304 | atomic_dec(&p->user->processes); |
| 1305 | free_uid(p->user); |
| 1306 | bad_fork_free: |
| 1307 | free_task(p); |
Oleg Nesterov | fe7d37d | 2006-01-08 01:04:02 -0800 | [diff] [blame] | 1308 | fork_out: |
| 1309 | return ERR_PTR(retval); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1310 | } |
| 1311 | |
Jeremy Fitzhardinge | f95d47c | 2006-12-07 02:14:02 +0100 | [diff] [blame] | 1312 | noinline struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1313 | { |
| 1314 | memset(regs, 0, sizeof(struct pt_regs)); |
| 1315 | return regs; |
| 1316 | } |
| 1317 | |
Al Viro | 9abcf40 | 2007-02-01 13:52:48 +0000 | [diff] [blame] | 1318 | struct task_struct * __cpuinit fork_idle(int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1319 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1320 | struct task_struct *task; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1321 | struct pt_regs regs; |
| 1322 | |
| 1323 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0); |
Akinobu Mita | 753ca4f | 2006-11-25 11:09:34 -0800 | [diff] [blame] | 1324 | if (!IS_ERR(task)) |
| 1325 | init_idle(task, cpu); |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1326 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1327 | return task; |
| 1328 | } |
| 1329 | |
| 1330 | static inline int fork_traceflag (unsigned clone_flags) |
| 1331 | { |
| 1332 | if (clone_flags & CLONE_UNTRACED) |
| 1333 | return 0; |
| 1334 | else if (clone_flags & CLONE_VFORK) { |
| 1335 | if (current->ptrace & PT_TRACE_VFORK) |
| 1336 | return PTRACE_EVENT_VFORK; |
| 1337 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { |
| 1338 | if (current->ptrace & PT_TRACE_CLONE) |
| 1339 | return PTRACE_EVENT_CLONE; |
| 1340 | } else if (current->ptrace & PT_TRACE_FORK) |
| 1341 | return PTRACE_EVENT_FORK; |
| 1342 | |
| 1343 | return 0; |
| 1344 | } |
| 1345 | |
| 1346 | /* |
| 1347 | * Ok, this is the main fork-routine. |
| 1348 | * |
| 1349 | * It copies the process, and if successful kick-starts |
| 1350 | * it and waits for it to finish using the VM if required. |
| 1351 | */ |
| 1352 | long do_fork(unsigned long clone_flags, |
| 1353 | unsigned long stack_start, |
| 1354 | struct pt_regs *regs, |
| 1355 | unsigned long stack_size, |
| 1356 | int __user *parent_tidptr, |
| 1357 | int __user *child_tidptr) |
| 1358 | { |
| 1359 | struct task_struct *p; |
| 1360 | int trace = 0; |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1361 | struct pid *pid = alloc_pid(); |
| 1362 | long nr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1363 | |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1364 | if (!pid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1365 | return -EAGAIN; |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1366 | nr = pid->nr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1367 | if (unlikely(current->ptrace)) { |
| 1368 | trace = fork_traceflag (clone_flags); |
| 1369 | if (trace) |
| 1370 | clone_flags |= CLONE_PTRACE; |
| 1371 | } |
| 1372 | |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1373 | p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1374 | /* |
| 1375 | * Do this prior waking up the new thread - the thread pointer |
| 1376 | * might get invalid after that point, if the thread exits quickly. |
| 1377 | */ |
| 1378 | if (!IS_ERR(p)) { |
| 1379 | struct completion vfork; |
| 1380 | |
| 1381 | if (clone_flags & CLONE_VFORK) { |
| 1382 | p->vfork_done = &vfork; |
| 1383 | init_completion(&vfork); |
| 1384 | } |
| 1385 | |
| 1386 | if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) { |
| 1387 | /* |
| 1388 | * We'll start up with an immediate SIGSTOP. |
| 1389 | */ |
| 1390 | sigaddset(&p->pending.signal, SIGSTOP); |
| 1391 | set_tsk_thread_flag(p, TIF_SIGPENDING); |
| 1392 | } |
| 1393 | |
| 1394 | if (!(clone_flags & CLONE_STOPPED)) |
| 1395 | wake_up_new_task(p, clone_flags); |
| 1396 | else |
| 1397 | p->state = TASK_STOPPED; |
| 1398 | |
| 1399 | if (unlikely (trace)) { |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1400 | current->ptrace_message = nr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1401 | ptrace_notify ((trace << 8) | SIGTRAP); |
| 1402 | } |
| 1403 | |
| 1404 | if (clone_flags & CLONE_VFORK) { |
| 1405 | wait_for_completion(&vfork); |
Chuck Ebbert | 9f59ce5 | 2006-08-05 12:14:11 -0700 | [diff] [blame] | 1406 | if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) { |
| 1407 | current->ptrace_message = nr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1408 | ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP); |
Chuck Ebbert | 9f59ce5 | 2006-08-05 12:14:11 -0700 | [diff] [blame] | 1409 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1410 | } |
| 1411 | } else { |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1412 | free_pid(pid); |
| 1413 | nr = PTR_ERR(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1414 | } |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1415 | return nr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1416 | } |
| 1417 | |
Ravikiran G Thirumalai | 5fd63b3 | 2006-01-11 22:46:15 +0100 | [diff] [blame] | 1418 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
| 1419 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 |
| 1420 | #endif |
| 1421 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 1422 | static void sighand_ctor(void *data, struct kmem_cache *cachep, unsigned long flags) |
Oleg Nesterov | aa1757f | 2006-03-28 16:11:12 -0800 | [diff] [blame] | 1423 | { |
| 1424 | struct sighand_struct *sighand = data; |
| 1425 | |
| 1426 | if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) == |
| 1427 | SLAB_CTOR_CONSTRUCTOR) |
| 1428 | spin_lock_init(&sighand->siglock); |
| 1429 | } |
| 1430 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1431 | void __init proc_caches_init(void) |
| 1432 | { |
| 1433 | sighand_cachep = kmem_cache_create("sighand_cache", |
| 1434 | sizeof(struct sighand_struct), 0, |
Oleg Nesterov | aa1757f | 2006-03-28 16:11:12 -0800 | [diff] [blame] | 1435 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU, |
| 1436 | sighand_ctor, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1437 | signal_cachep = kmem_cache_create("signal_cache", |
| 1438 | sizeof(struct signal_struct), 0, |
| 1439 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
| 1440 | files_cachep = kmem_cache_create("files_cache", |
| 1441 | sizeof(struct files_struct), 0, |
| 1442 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
| 1443 | fs_cachep = kmem_cache_create("fs_cache", |
| 1444 | sizeof(struct fs_struct), 0, |
| 1445 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
| 1446 | vm_area_cachep = kmem_cache_create("vm_area_struct", |
| 1447 | sizeof(struct vm_area_struct), 0, |
| 1448 | SLAB_PANIC, NULL, NULL); |
| 1449 | mm_cachep = kmem_cache_create("mm_struct", |
Ravikiran G Thirumalai | 5fd63b3 | 2006-01-11 22:46:15 +0100 | [diff] [blame] | 1450 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1451 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); |
| 1452 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1453 | |
| 1454 | |
| 1455 | /* |
| 1456 | * Check constraints on flags passed to the unshare system call and |
| 1457 | * force unsharing of additional process context as appropriate. |
| 1458 | */ |
| 1459 | static inline void check_unshare_flags(unsigned long *flags_ptr) |
| 1460 | { |
| 1461 | /* |
| 1462 | * If unsharing a thread from a thread group, must also |
| 1463 | * unshare vm. |
| 1464 | */ |
| 1465 | if (*flags_ptr & CLONE_THREAD) |
| 1466 | *flags_ptr |= CLONE_VM; |
| 1467 | |
| 1468 | /* |
| 1469 | * If unsharing vm, must also unshare signal handlers. |
| 1470 | */ |
| 1471 | if (*flags_ptr & CLONE_VM) |
| 1472 | *flags_ptr |= CLONE_SIGHAND; |
| 1473 | |
| 1474 | /* |
| 1475 | * If unsharing signal handlers and the task was created |
| 1476 | * using CLONE_THREAD, then must unshare the thread |
| 1477 | */ |
| 1478 | if ((*flags_ptr & CLONE_SIGHAND) && |
| 1479 | (atomic_read(¤t->signal->count) > 1)) |
| 1480 | *flags_ptr |= CLONE_THREAD; |
| 1481 | |
| 1482 | /* |
| 1483 | * If unsharing namespace, must also unshare filesystem information. |
| 1484 | */ |
| 1485 | if (*flags_ptr & CLONE_NEWNS) |
| 1486 | *flags_ptr |= CLONE_FS; |
| 1487 | } |
| 1488 | |
| 1489 | /* |
| 1490 | * Unsharing of tasks created with CLONE_THREAD is not supported yet |
| 1491 | */ |
| 1492 | static int unshare_thread(unsigned long unshare_flags) |
| 1493 | { |
| 1494 | if (unshare_flags & CLONE_THREAD) |
| 1495 | return -EINVAL; |
| 1496 | |
| 1497 | return 0; |
| 1498 | } |
| 1499 | |
| 1500 | /* |
JANAK DESAI | 99d1419 | 2006-02-07 12:58:59 -0800 | [diff] [blame] | 1501 | * Unshare the filesystem structure if it is being shared |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1502 | */ |
| 1503 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) |
| 1504 | { |
| 1505 | struct fs_struct *fs = current->fs; |
| 1506 | |
| 1507 | if ((unshare_flags & CLONE_FS) && |
JANAK DESAI | 99d1419 | 2006-02-07 12:58:59 -0800 | [diff] [blame] | 1508 | (fs && atomic_read(&fs->count) > 1)) { |
| 1509 | *new_fsp = __copy_fs_struct(current->fs); |
| 1510 | if (!*new_fsp) |
| 1511 | return -ENOMEM; |
| 1512 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1513 | |
| 1514 | return 0; |
| 1515 | } |
| 1516 | |
| 1517 | /* |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1518 | * Unshare the mnt_namespace structure if it is being shared |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1519 | */ |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1520 | static int unshare_mnt_namespace(unsigned long unshare_flags, |
| 1521 | struct mnt_namespace **new_nsp, struct fs_struct *new_fs) |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1522 | { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1523 | struct mnt_namespace *ns = current->nsproxy->mnt_ns; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1524 | |
Serge E. Hallyn | 1651e14 | 2006-10-02 02:18:08 -0700 | [diff] [blame] | 1525 | if ((unshare_flags & CLONE_NEWNS) && ns) { |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1526 | if (!capable(CAP_SYS_ADMIN)) |
| 1527 | return -EPERM; |
| 1528 | |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1529 | *new_nsp = dup_mnt_ns(current, new_fs ? new_fs : current->fs); |
JANAK DESAI | 741a295 | 2006-02-07 12:59:00 -0800 | [diff] [blame] | 1530 | if (!*new_nsp) |
| 1531 | return -ENOMEM; |
| 1532 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1533 | |
| 1534 | return 0; |
| 1535 | } |
| 1536 | |
| 1537 | /* |
Oleg Nesterov | dae3c5a | 2006-12-08 02:36:09 -0800 | [diff] [blame] | 1538 | * Unsharing of sighand is not supported yet |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1539 | */ |
| 1540 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) |
| 1541 | { |
| 1542 | struct sighand_struct *sigh = current->sighand; |
| 1543 | |
Oleg Nesterov | dae3c5a | 2006-12-08 02:36:09 -0800 | [diff] [blame] | 1544 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1545 | return -EINVAL; |
| 1546 | else |
| 1547 | return 0; |
| 1548 | } |
| 1549 | |
| 1550 | /* |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 1551 | * Unshare vm if it is being shared |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1552 | */ |
| 1553 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) |
| 1554 | { |
| 1555 | struct mm_struct *mm = current->mm; |
| 1556 | |
| 1557 | if ((unshare_flags & CLONE_VM) && |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 1558 | (mm && atomic_read(&mm->mm_users) > 1)) { |
Oleg Nesterov | 2d61b86 | 2006-03-18 20:41:10 +0300 | [diff] [blame] | 1559 | return -EINVAL; |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 1560 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1561 | |
| 1562 | return 0; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1563 | } |
| 1564 | |
| 1565 | /* |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 1566 | * Unshare file descriptor table if it is being shared |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1567 | */ |
| 1568 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) |
| 1569 | { |
| 1570 | struct files_struct *fd = current->files; |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 1571 | int error = 0; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1572 | |
| 1573 | if ((unshare_flags & CLONE_FILES) && |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 1574 | (fd && atomic_read(&fd->count) > 1)) { |
| 1575 | *new_fdp = dup_fd(fd, &error); |
| 1576 | if (!*new_fdp) |
| 1577 | return error; |
| 1578 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1579 | |
| 1580 | return 0; |
| 1581 | } |
| 1582 | |
| 1583 | /* |
| 1584 | * Unsharing of semundo for tasks created with CLONE_SYSVSEM is not |
| 1585 | * supported yet |
| 1586 | */ |
| 1587 | static int unshare_semundo(unsigned long unshare_flags, struct sem_undo_list **new_ulistp) |
| 1588 | { |
| 1589 | if (unshare_flags & CLONE_SYSVSEM) |
| 1590 | return -EINVAL; |
| 1591 | |
| 1592 | return 0; |
| 1593 | } |
| 1594 | |
Kirill Korotaev | 73ea413 | 2006-10-02 02:18:20 -0700 | [diff] [blame] | 1595 | #ifndef CONFIG_IPC_NS |
| 1596 | static inline int unshare_ipcs(unsigned long flags, struct ipc_namespace **ns) |
| 1597 | { |
| 1598 | if (flags & CLONE_NEWIPC) |
| 1599 | return -EINVAL; |
| 1600 | |
| 1601 | return 0; |
| 1602 | } |
| 1603 | #endif |
| 1604 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1605 | /* |
| 1606 | * unshare allows a process to 'unshare' part of the process |
| 1607 | * context which was originally shared using clone. copy_* |
| 1608 | * functions used by do_fork() cannot be used here directly |
| 1609 | * because they modify an inactive task_struct that is being |
| 1610 | * constructed. Here we are modifying the current, active, |
| 1611 | * task_struct. |
| 1612 | */ |
| 1613 | asmlinkage long sys_unshare(unsigned long unshare_flags) |
| 1614 | { |
| 1615 | int err = 0; |
| 1616 | struct fs_struct *fs, *new_fs = NULL; |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1617 | struct mnt_namespace *ns, *new_ns = NULL; |
Oleg Nesterov | dae3c5a | 2006-12-08 02:36:09 -0800 | [diff] [blame] | 1618 | struct sighand_struct *new_sigh = NULL; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1619 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
| 1620 | struct files_struct *fd, *new_fd = NULL; |
| 1621 | struct sem_undo_list *new_ulist = NULL; |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1622 | struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL; |
Serge E. Hallyn | 071df10 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 1623 | struct uts_namespace *uts, *new_uts = NULL; |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1624 | struct ipc_namespace *ipc, *new_ipc = NULL; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1625 | |
| 1626 | check_unshare_flags(&unshare_flags); |
| 1627 | |
Eric W. Biederman | 06f9d4f | 2006-03-22 00:07:40 -0800 | [diff] [blame] | 1628 | /* Return -EINVAL for all unsupported flags */ |
| 1629 | err = -EINVAL; |
| 1630 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1631 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
| 1632 | CLONE_NEWUTS|CLONE_NEWIPC)) |
Eric W. Biederman | 06f9d4f | 2006-03-22 00:07:40 -0800 | [diff] [blame] | 1633 | goto bad_unshare_out; |
| 1634 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1635 | if ((err = unshare_thread(unshare_flags))) |
| 1636 | goto bad_unshare_out; |
| 1637 | if ((err = unshare_fs(unshare_flags, &new_fs))) |
| 1638 | goto bad_unshare_cleanup_thread; |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1639 | if ((err = unshare_mnt_namespace(unshare_flags, &new_ns, new_fs))) |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1640 | goto bad_unshare_cleanup_fs; |
| 1641 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
| 1642 | goto bad_unshare_cleanup_ns; |
| 1643 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
| 1644 | goto bad_unshare_cleanup_sigh; |
| 1645 | if ((err = unshare_fd(unshare_flags, &new_fd))) |
| 1646 | goto bad_unshare_cleanup_vm; |
| 1647 | if ((err = unshare_semundo(unshare_flags, &new_ulist))) |
| 1648 | goto bad_unshare_cleanup_fd; |
Serge E. Hallyn | 071df10 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 1649 | if ((err = unshare_utsname(unshare_flags, &new_uts))) |
| 1650 | goto bad_unshare_cleanup_semundo; |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1651 | if ((err = unshare_ipcs(unshare_flags, &new_ipc))) |
| 1652 | goto bad_unshare_cleanup_uts; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1653 | |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1654 | if (new_ns || new_uts || new_ipc) { |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1655 | old_nsproxy = current->nsproxy; |
| 1656 | new_nsproxy = dup_namespaces(old_nsproxy); |
| 1657 | if (!new_nsproxy) { |
| 1658 | err = -ENOMEM; |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1659 | goto bad_unshare_cleanup_ipc; |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1660 | } |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1661 | } |
| 1662 | |
Oleg Nesterov | dae3c5a | 2006-12-08 02:36:09 -0800 | [diff] [blame] | 1663 | if (new_fs || new_ns || new_mm || new_fd || new_ulist || |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1664 | new_uts || new_ipc) { |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1665 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1666 | task_lock(current); |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1667 | |
| 1668 | if (new_nsproxy) { |
| 1669 | current->nsproxy = new_nsproxy; |
| 1670 | new_nsproxy = old_nsproxy; |
| 1671 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1672 | |
| 1673 | if (new_fs) { |
| 1674 | fs = current->fs; |
| 1675 | current->fs = new_fs; |
| 1676 | new_fs = fs; |
| 1677 | } |
| 1678 | |
| 1679 | if (new_ns) { |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1680 | ns = current->nsproxy->mnt_ns; |
| 1681 | current->nsproxy->mnt_ns = new_ns; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1682 | new_ns = ns; |
| 1683 | } |
| 1684 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1685 | if (new_mm) { |
| 1686 | mm = current->mm; |
| 1687 | active_mm = current->active_mm; |
| 1688 | current->mm = new_mm; |
| 1689 | current->active_mm = new_mm; |
| 1690 | activate_mm(active_mm, new_mm); |
| 1691 | new_mm = mm; |
| 1692 | } |
| 1693 | |
| 1694 | if (new_fd) { |
| 1695 | fd = current->files; |
| 1696 | current->files = new_fd; |
| 1697 | new_fd = fd; |
| 1698 | } |
| 1699 | |
Serge E. Hallyn | 071df10 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 1700 | if (new_uts) { |
| 1701 | uts = current->nsproxy->uts_ns; |
| 1702 | current->nsproxy->uts_ns = new_uts; |
| 1703 | new_uts = uts; |
| 1704 | } |
| 1705 | |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1706 | if (new_ipc) { |
| 1707 | ipc = current->nsproxy->ipc_ns; |
| 1708 | current->nsproxy->ipc_ns = new_ipc; |
| 1709 | new_ipc = ipc; |
| 1710 | } |
| 1711 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1712 | task_unlock(current); |
| 1713 | } |
| 1714 | |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1715 | if (new_nsproxy) |
Linus Torvalds | 444f378 | 2007-01-30 13:35:18 -0800 | [diff] [blame] | 1716 | put_nsproxy(new_nsproxy); |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1717 | |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1718 | bad_unshare_cleanup_ipc: |
| 1719 | if (new_ipc) |
| 1720 | put_ipc_ns(new_ipc); |
| 1721 | |
Serge E. Hallyn | 071df10 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 1722 | bad_unshare_cleanup_uts: |
| 1723 | if (new_uts) |
| 1724 | put_uts_ns(new_uts); |
| 1725 | |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1726 | bad_unshare_cleanup_semundo: |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1727 | bad_unshare_cleanup_fd: |
| 1728 | if (new_fd) |
| 1729 | put_files_struct(new_fd); |
| 1730 | |
| 1731 | bad_unshare_cleanup_vm: |
| 1732 | if (new_mm) |
| 1733 | mmput(new_mm); |
| 1734 | |
| 1735 | bad_unshare_cleanup_sigh: |
| 1736 | if (new_sigh) |
| 1737 | if (atomic_dec_and_test(&new_sigh->count)) |
| 1738 | kmem_cache_free(sighand_cachep, new_sigh); |
| 1739 | |
| 1740 | bad_unshare_cleanup_ns: |
| 1741 | if (new_ns) |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 1742 | put_mnt_ns(new_ns); |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1743 | |
| 1744 | bad_unshare_cleanup_fs: |
| 1745 | if (new_fs) |
| 1746 | put_fs_struct(new_fs); |
| 1747 | |
| 1748 | bad_unshare_cleanup_thread: |
| 1749 | bad_unshare_out: |
| 1750 | return err; |
| 1751 | } |