fs/exec.c

   1 /*
   2  *  linux/fs/exec.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /*
   8  * #!-checking implemented by tytso.
   9  */
  10 /*
  11  * Demand-loading implemented 01.12.91 - no need to read anything but
  12  * the header into memory. The inode of the executable is put into
  13  * "current->executable", and page faults do the actual loading. Clean.
  14  *
  15  * Once more I can proudly say that linux stood up to being changed: it
  16  * was less than 2 hours work to get demand-loading completely implemented.
  17  *
  18  * Demand loading changed July 1993 by Eric Youngdale.   Use mmap instead,
  19  * current->executable is only used by the procfs.  This allows a dispatch
  20  * table to check for several different types  of binary formats.  We keep
  21  * trying until we recognize the file or we run out of supported binary
  22  * formats.
  23  */
  24
  25 #include <linux/config.h>
  26 #include <linux/slab.h>
  27 #include <linux/file.h>
  28 #include <linux/mman.h>
  29 #include <linux/a.out.h>
  30 #include <linux/stat.h>
  31 #include <linux/fcntl.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/init.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/highmem.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/key.h>
  38 #include <linux/personality.h>
  39 #include <linux/binfmts.h>
  40 #include <linux/swap.h>
  41 #include <linux/utsname.h>
  42 #include <linux/module.h>
  43 #include <linux/namei.h>
  44 #include <linux/proc_fs.h>
  45 #include <linux/ptrace.h>
  46 #include <linux/mount.h>
  47 #include <linux/security.h>
  48 #include <linux/syscalls.h>
  49 #include <linux/rmap.h>
  50 #include <linux/acct.h>
  51
  52 #include <asm/uaccess.h>
  53 #include <asm/mmu_context.h>
  54
  55 #ifdef CONFIG_KMOD
  56 #include <linux/kmod.h>
  57 #endif
  58
  59 int core_uses_pid;
  60 char core_pattern[65] = "core";
  61 /* The maximal length of core_pattern is also specified in sysctl.c */
  62
  63 static struct linux_binfmt *formats;
  64 static rwlock_t binfmt_lock = RW_LOCK_UNLOCKED;
  65
  66 int register_binfmt(struct linux_binfmt * fmt)
  67 {
  68         struct linux_binfmt ** tmp = &formats;
  69
  70         if (!fmt)
  71                 return -EINVAL;
  72         if (fmt->next)
  73                 return -EBUSY;
  74         write_lock(&binfmt_lock);
  75         while (*tmp) {
  76                 if (fmt == *tmp) {
  77                         write_unlock(&binfmt_lock);
  78                         return -EBUSY;
  79                 }
  80                 tmp = &(*tmp)->next;
  81         }
  82         fmt->next = formats;
  83         formats = fmt;
  84         write_unlock(&binfmt_lock);
  85         return 0;
  86 }
  87
  88 EXPORT_SYMBOL(register_binfmt);
  89
  90 int unregister_binfmt(struct linux_binfmt * fmt)
  91 {
  92         struct linux_binfmt ** tmp = &formats;
  93
  94         write_lock(&binfmt_lock);
  95         while (*tmp) {
  96                 if (fmt == *tmp) {
  97                         *tmp = fmt->next;
  98                         write_unlock(&binfmt_lock);
  99                         return 0;
 100                 }
 101                 tmp = &(*tmp)->next;
 102         }
 103         write_unlock(&binfmt_lock);
 104         return -EINVAL;
 105 }
 106
 107 EXPORT_SYMBOL(unregister_binfmt);
 108
 109 static inline void put_binfmt(struct linux_binfmt * fmt)
 110 {
 111         module_put(fmt->module);
 112 }
 113
 114 /*
 115  * Note that a shared library must be both readable and executable due to
 116  * security reasons.
 117  *
 118  * Also note that we take the address to load from from the file itself.
 119  */
 120 asmlinkage long sys_uselib(const char __user * library)
 121 {
 122         struct file * file;
 123         struct nameidata nd;
 124         int error;
 125
 126         nd.intent.open.flags = FMODE_READ;
 127         error = __user_walk(library, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd);
 128         if (error)
 129                 goto out;
 130
 131         error = -EINVAL;
 132         if (!S_ISREG(nd.dentry->d_inode->i_mode))
 133                 goto exit;
 134
 135         error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd);
 136         if (error)
 137                 goto exit;
 138
 139         file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
 140         error = PTR_ERR(file);
 141         if (IS_ERR(file))
 142                 goto out;
 143
 144         error = -ENOEXEC;
 145         if(file->f_op) {
 146                 struct linux_binfmt * fmt;
 147
 148                 read_lock(&binfmt_lock);
 149                 for (fmt = formats ; fmt ; fmt = fmt->next) {
 150                         if (!fmt->load_shlib)
 151                                 continue;
 152                         if (!try_module_get(fmt->module))
 153                                 continue;
 154                         read_unlock(&binfmt_lock);
 155                         error = fmt->load_shlib(file);
 156                         read_lock(&binfmt_lock);
 157                         put_binfmt(fmt);
 158                         if (error != -ENOEXEC)
 159                                 break;
 160                 }
 161                 read_unlock(&binfmt_lock);
 162         }
 163         fput(file);
 164 out:
 165         return error;
 166 exit:
 167         path_release(&nd);
 168         goto out;
 169 }
 170
 171 /*
 172  * count() counts the number of strings in array ARGV.
 173  */
 174 static int count(char __user * __user * argv, int max)
 175 {
 176         int i = 0;
 177
 178         if (argv != NULL) {
 179                 for (;;) {
 180                         char __user * p;
 181
 182                         if (get_user(p, argv))
 183                                 return -EFAULT;
 184                         if (!p)
 185                                 break;
 186                         argv++;
 187                         if(++i > max)
 188                                 return -E2BIG;
 189                         cond_resched();
 190                 }
 191         }
 192         return i;
 193 }
 194
 195 /*
 196  * 'copy_strings()' copies argument/environment strings from user
 197  * memory to free pages in kernel mem. These are in a format ready
 198  * to be put directly into the top of new user memory.
 199  */
 200 int copy_strings(int argc,char __user * __user * argv, struct linux_binprm *bprm)
 201 {
 202         struct page *kmapped_page = NULL;
 203         char *kaddr = NULL;
 204         int ret;
 205
 206         while (argc-- > 0) {
 207                 char __user *str;
 208                 int len;
 209                 unsigned long pos;
 210
 211                 if (get_user(str, argv+argc) ||
 212                                 !(len = strnlen_user(str, bprm->p))) {
 213                         ret = -EFAULT;
 214                         goto out;
 215                 }
 216
 217                 if (bprm->p < len)  {
 218                         ret = -E2BIG;
 219                         goto out;
 220                 }
 221
 222                 bprm->p -= len;
 223                 /* XXX: add architecture specific overflow check here. */
 224                 pos = bprm->p;
 225
 226                 while (len > 0) {
 227                         int i, new, err;
 228                         int offset, bytes_to_copy;
 229                         struct page *page;
 230
 231                         offset = pos % PAGE_SIZE;
 232                         i = pos/PAGE_SIZE;
 233                         page = bprm->page[i];
 234                         new = 0;
 235                         if (!page) {
 236                                 page = alloc_page(GFP_HIGHUSER);
 237                                 bprm->page[i] = page;
 238                                 if (!page) {
 239                                         ret = -ENOMEM;
 240                                         goto out;
 241                                 }
 242                                 new = 1;
 243                         }
 244
 245                         if (page != kmapped_page) {
 246                                 if (kmapped_page)
 247                                         kunmap(kmapped_page);
 248                                 kmapped_page = page;
 249                                 kaddr = kmap(kmapped_page);
 250                         }
 251                         if (new && offset)
 252                                 memset(kaddr, 0, offset);
 253                         bytes_to_copy = PAGE_SIZE - offset;
 254                         if (bytes_to_copy > len) {
 255                                 bytes_to_copy = len;
 256                                 if (new)
 257                                         memset(kaddr+offset+len, 0,
 258                                                 PAGE_SIZE-offset-len);
 259                         }
 260                         err = copy_from_user(kaddr+offset, str, bytes_to_copy);
 261                         if (err) {
 262                                 ret = -EFAULT;
 263                                 goto out;
 264                         }
 265
 266                         pos += bytes_to_copy;
 267                         str += bytes_to_copy;
 268                         len -= bytes_to_copy;
 269                 }
 270         }
 271         ret = 0;
 272 out:
 273         if (kmapped_page)
 274                 kunmap(kmapped_page);
 275         return ret;
 276 }
 277
 278 /*
 279  * Like copy_strings, but get argv and its values from kernel memory.
 280  */
 281 int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
 282 {
 283         int r;
 284         mm_segment_t oldfs = get_fs();
 285         set_fs(KERNEL_DS);
 286         r = copy_strings(argc, (char __user * __user *)argv, bprm);
 287         set_fs(oldfs);
 288         return r;
 289 }
 290
 291 EXPORT_SYMBOL(copy_strings_kernel);
 292
 293 #ifdef CONFIG_MMU
 294 /*
 295  * This routine is used to map in a page into an address space: needed by
 296  * execve() for the initial stack and environment pages.
 297  *
 298  * vma->vm_mm->mmap_sem is held for writing.
 299  */
 300 void install_arg_page(struct vm_area_struct *vma,
 301                         struct page *page, unsigned long address)
 302 {
 303         struct mm_struct *mm = vma->vm_mm;
 304         pgd_t * pgd;
 305         pud_t * pud;
 306         pmd_t * pmd;
 307         pte_t * pte;
 308
 309         if (unlikely(anon_vma_prepare(vma)))
 310                 goto out_sig;
 311
 312         flush_dcache_page(page);
 313         pgd = pgd_offset(mm, address);
 314
 315         spin_lock(&mm->page_table_lock);
 316         pud = pud_alloc(mm, pgd, address);
 317         if (!pud)
 318                 goto out;
 319         pmd = pmd_alloc(mm, pud, address);
 320         if (!pmd)
 321                 goto out;
 322         pte = pte_alloc_map(mm, pmd, address);
 323         if (!pte)
 324                 goto out;
 325         if (!pte_none(*pte)) {
 326                 pte_unmap(pte);
 327                 goto out;
 328         }
 329         mm->rss++;
 330         lru_cache_add_active(page);
 331         set_pte(pte, pte_mkdirty(pte_mkwrite(mk_pte(
 332                                         page, vma->vm_page_prot))));
 333         page_add_anon_rmap(page, vma, address);
 334         pte_unmap(pte);
 335         spin_unlock(&mm->page_table_lock);
 336
 337         /* no need for flush_tlb */
 338         return;
 339 out:
 340         spin_unlock(&mm->page_table_lock);
 341 out_sig:
 342         __free_page(page);
 343         force_sig(SIGKILL, current);
 344 }
 345
 346 #define EXTRA_STACK_VM_PAGES    20      /* random */
 347
 348 int setup_arg_pages(struct linux_binprm *bprm,
 349                     unsigned long stack_top,
 350                     int executable_stack)
 351 {
 352         unsigned long stack_base;
 353         struct vm_area_struct *mpnt;
 354         struct mm_struct *mm = current->mm;
 355         int i, ret;
 356         long arg_size;
 357
 358 #ifdef CONFIG_STACK_GROWSUP
 359         /* Move the argument and environment strings to the bottom of the
 360          * stack space.
 361          */
 362         int offset, j;
 363         char *to, *from;
 364
 365         /* Start by shifting all the pages down */
 366         i = 0;
 367         for (j = 0; j < MAX_ARG_PAGES; j++) {
 368                 struct page *page = bprm->page[j];
 369                 if (!page)
 370                         continue;
 371                 bprm->page[i++] = page;
 372         }
 373
 374         /* Now move them within their pages */
 375         offset = bprm->p % PAGE_SIZE;
 376         to = kmap(bprm->page[0]);
 377         for (j = 1; j < i; j++) {
 378                 memmove(to, to + offset, PAGE_SIZE - offset);
 379                 from = kmap(bprm->page[j]);
 380                 memcpy(to + PAGE_SIZE - offset, from, offset);
 381                 kunmap(bprm->page[j - 1]);
 382                 to = from;
 383         }
 384         memmove(to, to + offset, PAGE_SIZE - offset);
 385         kunmap(bprm->page[j - 1]);
 386
 387         /* Limit stack size to 1GB */
 388         stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
 389         if (stack_base > (1 << 30))
 390                 stack_base = 1 << 30;
 391         stack_base = PAGE_ALIGN(stack_top - stack_base);
 392
 393         /* Adjust bprm->p to point to the end of the strings. */
 394         bprm->p = stack_base + PAGE_SIZE * i - offset;
 395
 396         mm->arg_start = stack_base;
 397         arg_size = i << PAGE_SHIFT;
 398
 399         /* zero pages that were copied above */
 400         while (i < MAX_ARG_PAGES)
 401                 bprm->page[i++] = NULL;
 402 #else
 403         stack_base = stack_top - MAX_ARG_PAGES * PAGE_SIZE;
 404         bprm->p += stack_base;
 405         mm->arg_start = bprm->p;
 406         arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
 407 #endif
 408
 409         arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
 410
 411         if (bprm->loader)
 412                 bprm->loader += stack_base;
 413         bprm->exec += stack_base;
 414
 415         mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 416         if (!mpnt)
 417                 return -ENOMEM;
 418
 419         if (security_vm_enough_memory(arg_size >> PAGE_SHIFT)) {
 420                 kmem_cache_free(vm_area_cachep, mpnt);
 421                 return -ENOMEM;
 422         }
 423
 424         memset(mpnt, 0, sizeof(*mpnt));
 425
 426         down_write(&mm->mmap_sem);
 427         {
 428                 mpnt->vm_mm = mm;
 429 #ifdef CONFIG_STACK_GROWSUP
 430                 mpnt->vm_start = stack_base;
 431                 mpnt->vm_end = stack_base + arg_size;
 432 #else
 433                 mpnt->vm_end = stack_top;
 434                 mpnt->vm_start = mpnt->vm_end - arg_size;
 435 #endif
 436                 /* Adjust stack execute permissions; explicitly enable
 437                  * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
 438                  * and leave alone (arch default) otherwise. */
 439                 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
 440                         mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
 441                 else if (executable_stack == EXSTACK_DISABLE_X)
 442                         mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
 443                 else
 444                         mpnt->vm_flags = VM_STACK_FLAGS;
 445                 mpnt->vm_flags |= mm->def_flags;
 446                 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
 447                 if ((ret = insert_vm_struct(mm, mpnt))) {
 448                         up_write(&mm->mmap_sem);
 449                         kmem_cache_free(vm_area_cachep, mpnt);
 450                         return ret;
 451                 }
 452                 mm->stack_vm = mm->total_vm = vma_pages(mpnt);
 453         }
 454
 455         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
 456                 struct page *page = bprm->page[i];
 457                 if (page) {
 458                         bprm->page[i] = NULL;
 459                         install_arg_page(mpnt, page, stack_base);
 460                 }
 461                 stack_base += PAGE_SIZE;
 462         }
 463         up_write(&mm->mmap_sem);
 464
 465         return 0;
 466 }
 467
 468 EXPORT_SYMBOL(setup_arg_pages);
 469
 470 #define free_arg_pages(bprm) do { } while (0)
 471
 472 #else
 473
 474 static inline void free_arg_pages(struct linux_binprm *bprm)
 475 {
 476         int i;
 477
 478         for (i = 0; i < MAX_ARG_PAGES; i++) {
 479                 if (bprm->page[i])
 480                         __free_page(bprm->page[i]);
 481                 bprm->page[i] = NULL;
 482         }
 483 }
 484
 485 #endif /* CONFIG_MMU */
 486
 487 struct file *open_exec(const char *name)
 488 {
 489         struct nameidata nd;
 490         int err;
 491         struct file *file;
 492
 493         nd.intent.open.flags = FMODE_READ;
 494         err = path_lookup(name, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd);
 495         file = ERR_PTR(err);
 496
 497         if (!err) {
 498                 struct inode *inode = nd.dentry->d_inode;
 499                 file = ERR_PTR(-EACCES);
 500                 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
 501                     S_ISREG(inode->i_mode)) {
 502                         int err = permission(inode, MAY_EXEC, &nd);
 503                         if (!err && !(inode->i_mode & 0111))
 504                                 err = -EACCES;
 505                         file = ERR_PTR(err);
 506                         if (!err) {
 507                                 file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
 508                                 if (!IS_ERR(file)) {
 509                                         err = deny_write_access(file);
 510                                         if (err) {
 511                                                 fput(file);
 512                                                 file = ERR_PTR(err);
 513                                         }
 514                                 }
 515 out:
 516                                 return file;
 517                         }
 518                 }
 519                 path_release(&nd);
 520         }
 521         goto out;
 522 }
 523
 524 EXPORT_SYMBOL(open_exec);
 525
 526 int kernel_read(struct file *file, unsigned long offset,
 527         char *addr, unsigned long count)
 528 {
 529         mm_segment_t old_fs;
 530         loff_t pos = offset;
 531         int result;
 532
 533         old_fs = get_fs();
 534         set_fs(get_ds());
 535         /* The cast to a user pointer is valid due to the set_fs() */
 536         result = vfs_read(file, (void __user *)addr, count, &pos);
 537         set_fs(old_fs);
 538         return result;
 539 }
 540
 541 EXPORT_SYMBOL(kernel_read);
 542
 543 static int exec_mmap(struct mm_struct *mm)
 544 {
 545         struct task_struct *tsk;
 546         struct mm_struct * old_mm, *active_mm;
 547
 548         /* Notify parent that we're no longer interested in the old VM */
 549         tsk = current;
 550         old_mm = current->mm;
 551         mm_release(tsk, old_mm);
 552
 553         if (old_mm) {
 554                 /*
 555                  * Make sure that if there is a core dump in progress
 556                  * for the old mm, we get out and die instead of going
 557                  * through with the exec.  We must hold mmap_sem around
 558                  * checking core_waiters and changing tsk->mm.  The
 559                  * core-inducing thread will increment core_waiters for
 560                  * each thread whose ->mm == old_mm.
 561                  */
 562                 down_read(&old_mm->mmap_sem);
 563                 if (unlikely(old_mm->core_waiters)) {
 564                         up_read(&old_mm->mmap_sem);
 565                         return -EINTR;
 566                 }
 567         }
 568         task_lock(tsk);
 569         active_mm = tsk->active_mm;
 570         tsk->mm = mm;
 571         tsk->active_mm = mm;
 572         activate_mm(active_mm, mm);
 573         task_unlock(tsk);
 574         arch_pick_mmap_layout(mm);
 575         if (old_mm) {
 576                 up_read(&old_mm->mmap_sem);
 577                 if (active_mm != old_mm) BUG();
 578                 mmput(old_mm);
 579                 return 0;
 580         }
 581         mmdrop(active_mm);
 582         return 0;
 583 }
 584
 585 /*
 586  * This function makes sure the current process has its own signal table,
 587  * so that flush_signal_handlers can later reset the handlers without
 588  * disturbing other processes.  (Other processes might share the signal
 589  * table via the CLONE_SIGHAND option to clone().)
 590  */
 591 static inline int de_thread(struct task_struct *tsk)
 592 {
 593         struct signal_struct *sig = tsk->signal;
 594         struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
 595         spinlock_t *lock = &oldsighand->siglock;
 596         int count;
 597
 598         /*
 599          * If we don't share sighandlers, then we aren't sharing anything
 600          * and we can just re-use it all.
 601          */
 602         if (atomic_read(&oldsighand->count) <= 1) {
 603                 BUG_ON(atomic_read(&sig->count) != 1);
 604                 exit_itimers(sig);
 605                 return 0;
 606         }
 607
 608         newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
 609         if (!newsighand)
 610                 return -ENOMEM;
 611
 612         if (thread_group_empty(current))
 613                 goto no_thread_group;
 614
 615         /*
 616          * Kill all other threads in the thread group.
 617          * We must hold tasklist_lock to call zap_other_threads.
 618          */
 619         read_lock(&tasklist_lock);
 620         spin_lock_irq(lock);
 621         if (sig->flags & SIGNAL_GROUP_EXIT) {
 622                 /*
 623                  * Another group action in progress, just
 624                  * return so that the signal is processed.
 625                  */
 626                 spin_unlock_irq(lock);
 627                 read_unlock(&tasklist_lock);
 628                 kmem_cache_free(sighand_cachep, newsighand);
 629                 return -EAGAIN;
 630         }
 631         zap_other_threads(current);
 632         read_unlock(&tasklist_lock);
 633
 634         /*
 635          * Account for the thread group leader hanging around:
 636          */
 637         count = 2;
 638         if (thread_group_leader(current))
 639                 count = 1;
 640         while (atomic_read(&sig->count) > count) {
 641                 sig->group_exit_task = current;
 642                 sig->notify_count = count;
 643                 __set_current_state(TASK_UNINTERRUPTIBLE);
 644                 spin_unlock_irq(lock);
 645                 schedule();
 646                 spin_lock_irq(lock);
 647         }
 648         sig->group_exit_task = NULL;
 649         sig->notify_count = 0;
 650         spin_unlock_irq(lock);
 651
 652         /*
 653          * At this point all other threads have exited, all we have to
 654          * do is to wait for the thread group leader to become inactive,
 655          * and to assume its PID:
 656          */
 657         if (!thread_group_leader(current)) {
 658                 struct task_struct *leader = current->group_leader, *parent;
 659                 struct dentry *proc_dentry1, *proc_dentry2;
 660                 unsigned long exit_state, ptrace;
 661
 662                 /*
 663                  * Wait for the thread group leader to be a zombie.
 664                  * It should already be zombie at this point, most
 665                  * of the time.
 666                  */
 667                 while (leader->exit_state != EXIT_ZOMBIE)
 668                         yield();
 669
 670                 spin_lock(&leader->proc_lock);
 671                 spin_lock(&current->proc_lock);
 672                 proc_dentry1 = proc_pid_unhash(current);
 673                 proc_dentry2 = proc_pid_unhash(leader);
 674                 write_lock_irq(&tasklist_lock);
 675
 676                 if (leader->tgid != current->tgid)
 677                         BUG();
 678                 if (current->pid == current->tgid)
 679                         BUG();
 680                 /*
 681                  * An exec() starts a new thread group with the
 682                  * TGID of the previous thread group. Rehash the
 683                  * two threads with a switched PID, and release
 684                  * the former thread group leader:
 685                  */
 686                 ptrace = leader->ptrace;
 687                 parent = leader->parent;
 688                 if (unlikely(ptrace) && unlikely(parent == current)) {
 689                         /*
 690                          * Joker was ptracing his own group leader,
 691                          * and now he wants to be his own parent!
 692                          * We can't have that.
 693                          */
 694                         ptrace = 0;
 695                 }
 696
 697                 ptrace_unlink(current);
 698                 ptrace_unlink(leader);
 699                 remove_parent(current);
 700                 remove_parent(leader);
 701
 702                 switch_exec_pids(leader, current);
 703
 704                 current->parent = current->real_parent = leader->real_parent;
 705                 leader->parent = leader->real_parent = child_reaper;
 706                 current->group_leader = current;
 707                 leader->group_leader = leader;
 708
 709                 add_parent(current, current->parent);
 710                 add_parent(leader, leader->parent);
 711                 if (ptrace) {
 712                         current->ptrace = ptrace;
 713                         __ptrace_link(current, parent);
 714                 }
 715
 716                 list_del(&current->tasks);
 717                 list_add_tail(&current->tasks, &init_task.tasks);
 718                 current->exit_signal = SIGCHLD;
 719                 exit_state = leader->exit_state;
 720
 721                 write_unlock_irq(&tasklist_lock);
 722                 spin_unlock(&leader->proc_lock);
 723                 spin_unlock(&current->proc_lock);
 724                 proc_pid_flush(proc_dentry1);
 725                 proc_pid_flush(proc_dentry2);
 726
 727                 if (exit_state != EXIT_ZOMBIE)
 728                         BUG();
 729                 release_task(leader);
 730         }
 731
 732         /*
 733          * Now there are really no other threads at all,
 734          * so it's safe to stop telling them to kill themselves.
 735          */
 736         sig->flags = 0;
 737
 738 no_thread_group:
 739         BUG_ON(atomic_read(&sig->count) != 1);
 740         exit_itimers(sig);
 741
 742         if (atomic_read(&oldsighand->count) == 1) {
 743                 /*
 744                  * Now that we nuked the rest of the thread group,
 745                  * it turns out we are not sharing sighand any more either.
 746                  * So we can just keep it.
 747                  */
 748                 kmem_cache_free(sighand_cachep, newsighand);
 749         } else {
 750                 /*
 751                  * Move our state over to newsighand and switch it in.
 752                  */
 753                 spin_lock_init(&newsighand->siglock);
 754                 atomic_set(&newsighand->count, 1);
 755                 memcpy(newsighand->action, oldsighand->action,
 756                        sizeof(newsighand->action));
 757
 758                 write_lock_irq(&tasklist_lock);
 759                 spin_lock(&oldsighand->siglock);
 760                 spin_lock(&newsighand->siglock);
 761
 762                 current->sighand = newsighand;
 763                 recalc_sigpending();
 764
 765                 spin_unlock(&newsighand->siglock);
 766                 spin_unlock(&oldsighand->siglock);
 767                 write_unlock_irq(&tasklist_lock);
 768
 769                 if (atomic_dec_and_test(&oldsighand->count))
 770                         kmem_cache_free(sighand_cachep, oldsighand);
 771         }
 772
 773         if (!thread_group_empty(current))
 774                 BUG();
 775         if (!thread_group_leader(current))
 776                 BUG();
 777         return 0;
 778 }
 779
 780 /*
 781  * These functions flushes out all traces of the currently running executable
 782  * so that a new one can be started
 783  */
 784
 785 static inline void flush_old_files(struct files_struct * files)
 786 {
 787         long j = -1;
 788
 789         spin_lock(&files->file_lock);
 790         for (;;) {
 791                 unsigned long set, i;
 792
 793                 j++;
 794                 i = j * __NFDBITS;
 795                 if (i >= files->max_fds || i >= files->max_fdset)
 796                         break;
 797                 set = files->close_on_exec->fds_bits[j];
 798                 if (!set)
 799                         continue;
 800                 files->close_on_exec->fds_bits[j] = 0;
 801                 spin_unlock(&files->file_lock);
 802                 for ( ; set ; i++,set >>= 1) {
 803                         if (set & 1) {
 804                                 sys_close(i);
 805                         }
 806                 }
 807                 spin_lock(&files->file_lock);
 808
 809         }
 810         spin_unlock(&files->file_lock);
 811 }
 812
 813 void get_task_comm(char *buf, struct task_struct *tsk)
 814 {
 815         /* buf must be at least sizeof(tsk->comm) in size */
 816         task_lock(tsk);
 817         memcpy(buf, tsk->comm, sizeof(tsk->comm));
 818         task_unlock(tsk);
 819 }
 820
 821 void set_task_comm(struct task_struct *tsk, char *buf)
 822 {
 823         task_lock(tsk);
 824         strlcpy(tsk->comm, buf, sizeof(tsk->comm));
 825         task_unlock(tsk);
 826 }
 827
 828 int flush_old_exec(struct linux_binprm * bprm)
 829 {
 830         char * name;
 831         int i, ch, retval;
 832         struct files_struct *files;
 833         char tcomm[sizeof(current->comm)];
 834
 835         /*
 836          * Make sure we have a private signal table and that
 837          * we are unassociated from the previous thread group.
 838          */
 839         retval = de_thread(current);
 840         if (retval)
 841                 goto out;
 842
 843         /*
 844          * Make sure we have private file handles. Ask the
 845          * fork helper to do the work for us and the exit
 846          * helper to do the cleanup of the old one.
 847          */
 848         files = current->files;         /* refcounted so safe to hold */
 849         retval = unshare_files();
 850         if (retval)
 851                 goto out;
 852         /*
 853          * Release all of the old mmap stuff
 854          */
 855         retval = exec_mmap(bprm->mm);
 856         if (retval)
 857                 goto mmap_failed;
 858
 859         bprm->mm = NULL;                /* We're using it now */
 860
 861         /* This is the point of no return */
 862         steal_locks(files);
 863         put_files_struct(files);
 864
 865         current->sas_ss_sp = current->sas_ss_size = 0;
 866
 867         if (current->euid == current->uid && current->egid == current->gid)
 868                 current->mm->dumpable = 1;
 869         name = bprm->filename;
 870         for (i=0; (ch = *(name++)) != '\0';) {
 871                 if (ch == '/')
 872                         i = 0;
 873                 else
 874                         if (i < (sizeof(tcomm) - 1))
 875                                 tcomm[i++] = ch;
 876         }
 877         tcomm[i] = '\0';
 878         set_task_comm(current, tcomm);
 879
 880         flush_thread();
 881
 882         if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
 883             permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) ||
 884             (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
 885                 suid_keys(current);
 886                 current->mm->dumpable = 0;
 887         }
 888
 889         /* An exec changes our domain. We are no longer part of the thread
 890            group */
 891
 892         current->self_exec_id++;
 893
 894         flush_signal_handlers(current, 0);
 895         flush_old_files(current->files);
 896
 897         return 0;
 898
 899 mmap_failed:
 900         put_files_struct(current->files);
 901         current->files = files;
 902 out:
 903         return retval;
 904 }
 905
 906 EXPORT_SYMBOL(flush_old_exec);
 907
 908 /*
 909  * Fill the binprm structure from the inode.
 910  * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
 911  */
 912 int prepare_binprm(struct linux_binprm *bprm)
 913 {
 914         int mode;
 915         struct inode * inode = bprm->file->f_dentry->d_inode;
 916         int retval;
 917
 918         mode = inode->i_mode;
 919         /*
 920          * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
 921          * generic_permission lets a non-executable through
 922          */
 923         if (!(mode & 0111))     /* with at least _one_ execute bit set */
 924                 return -EACCES;
 925         if (bprm->file->f_op == NULL)
 926                 return -EACCES;
 927
 928         bprm->e_uid = current->euid;
 929         bprm->e_gid = current->egid;
 930
 931         if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) {
 932                 /* Set-uid? */
 933                 if (mode & S_ISUID) {
 934                         current->personality &= ~PER_CLEAR_ON_SETID;
 935                         bprm->e_uid = inode->i_uid;
 936                 }
 937
 938                 /* Set-gid? */
 939                 /*
 940                  * If setgid is set but no group execute bit then this
 941                  * is a candidate for mandatory locking, not a setgid
 942                  * executable.
 943                  */
 944                 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
 945                         current->personality &= ~PER_CLEAR_ON_SETID;
 946                         bprm->e_gid = inode->i_gid;
 947                 }
 948         }
 949
 950         /* fill in binprm security blob */
 951         retval = security_bprm_set(bprm);
 952         if (retval)
 953                 return retval;
 954
 955         memset(bprm->buf,0,BINPRM_BUF_SIZE);
 956         return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
 957 }
 958
 959 EXPORT_SYMBOL(prepare_binprm);
 960
 961 static inline int unsafe_exec(struct task_struct *p)
 962 {
 963         int unsafe = 0;
 964         if (p->ptrace & PT_PTRACED) {
 965                 if (p->ptrace & PT_PTRACE_CAP)
 966                         unsafe |= LSM_UNSAFE_PTRACE_CAP;
 967                 else
 968                         unsafe |= LSM_UNSAFE_PTRACE;
 969         }
 970         if (atomic_read(&p->fs->count) > 1 ||
 971             atomic_read(&p->files->count) > 1 ||
 972             atomic_read(&p->sighand->count) > 1)
 973                 unsafe |= LSM_UNSAFE_SHARE;
 974
 975         return unsafe;
 976 }
 977
 978 void compute_creds(struct linux_binprm *bprm)
 979 {
 980         int unsafe;
 981
 982         if (bprm->e_uid != current->uid)
 983                 suid_keys(current);
 984         exec_keys(current);
 985
 986         task_lock(current);
 987         unsafe = unsafe_exec(current);
 988         security_bprm_apply_creds(bprm, unsafe);
 989         task_unlock(current);
 990         security_bprm_post_apply_creds(bprm);
 991 }
 992
 993 EXPORT_SYMBOL(compute_creds);
 994
 995 void remove_arg_zero(struct linux_binprm *bprm)
 996 {
 997         if (bprm->argc) {
 998                 unsigned long offset;
 999                 char * kaddr;
1000                 struct page *page;
1001
1002                 offset = bprm->p % PAGE_SIZE;
1003                 goto inside;
1004
1005                 while (bprm->p++, *(kaddr+offset++)) {
1006                         if (offset != PAGE_SIZE)
1007                                 continue;
1008                         offset = 0;
1009                         kunmap_atomic(kaddr, KM_USER0);
1010 inside:
1011                         page = bprm->page[bprm->p/PAGE_SIZE];
1012                         kaddr = kmap_atomic(page, KM_USER0);
1013                 }
1014                 kunmap_atomic(kaddr, KM_USER0);
1015                 bprm->argc--;
1016         }
1017 }
1018
1019 EXPORT_SYMBOL(remove_arg_zero);
1020
1021 /*
1022  * cycle the list of binary formats handler, until one recognizes the image
1023  */
1024 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1025 {
1026         int try,retval;
1027         struct linux_binfmt *fmt;
1028 #ifdef __alpha__
1029         /* handle /sbin/loader.. */
1030         {
1031             struct exec * eh = (struct exec *) bprm->buf;
1032
1033             if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1034                 (eh->fh.f_flags & 0x3000) == 0x3000)
1035             {
1036                 struct file * file;
1037                 unsigned long loader;
1038
1039                 allow_write_access(bprm->file);
1040                 fput(bprm->file);
1041                 bprm->file = NULL;
1042
1043                 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1044
1045                 file = open_exec("/sbin/loader");
1046                 retval = PTR_ERR(file);
1047                 if (IS_ERR(file))
1048                         return retval;
1049
1050                 /* Remember if the application is TASO.  */
1051                 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1052
1053                 bprm->file = file;
1054                 bprm->loader = loader;
1055                 retval = prepare_binprm(bprm);
1056                 if (retval<0)
1057                         return retval;
1058                 /* should call search_binary_handler recursively here,
1059                    but it does not matter */
1060             }
1061         }
1062 #endif
1063         retval = security_bprm_check(bprm);
1064         if (retval)
1065                 return retval;
1066
1067         /* kernel module loader fixup */
1068         /* so we don't try to load run modprobe in kernel space. */
1069         set_fs(USER_DS);
1070         retval = -ENOENT;
1071         for (try=0; try<2; try++) {
1072                 read_lock(&binfmt_lock);
1073                 for (fmt = formats ; fmt ; fmt = fmt->next) {
1074                         int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1075                         if (!fn)
1076                                 continue;
1077                         if (!try_module_get(fmt->module))
1078                                 continue;
1079                         read_unlock(&binfmt_lock);
1080                         retval = fn(bprm, regs);
1081                         if (retval >= 0) {
1082                                 put_binfmt(fmt);
1083                                 allow_write_access(bprm->file);
1084                                 if (bprm->file)
1085                                         fput(bprm->file);
1086                                 bprm->file = NULL;
1087                                 current->did_exec = 1;
1088                                 return retval;
1089                         }
1090                         read_lock(&binfmt_lock);
1091                         put_binfmt(fmt);
1092                         if (retval != -ENOEXEC || bprm->mm == NULL)
1093                                 break;
1094                         if (!bprm->file) {
1095                                 read_unlock(&binfmt_lock);
1096                                 return retval;
1097                         }
1098                 }
1099                 read_unlock(&binfmt_lock);
1100                 if (retval != -ENOEXEC || bprm->mm == NULL) {
1101                         break;
1102 #ifdef CONFIG_KMOD
1103                 }else{
1104 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1105                         if (printable(bprm->buf[0]) &&
1106                             printable(bprm->buf[1]) &&
1107                             printable(bprm->buf[2]) &&
1108                             printable(bprm->buf[3]))
1109                                 break; /* -ENOEXEC */
1110                         request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1111 #endif
1112                 }
1113         }
1114         return retval;
1115 }
1116
1117 EXPORT_SYMBOL(search_binary_handler);
1118
1119 /*
1120  * sys_execve() executes a new program.
1121  */
1122 int do_execve(char * filename,
1123         char __user *__user *argv,
1124         char __user *__user *envp,
1125         struct pt_regs * regs)
1126 {
1127         struct linux_binprm *bprm;
1128         struct file *file;
1129         int retval;
1130         int i;
1131
1132         retval = -ENOMEM;
1133         bprm = kmalloc(sizeof(*bprm), GFP_KERNEL);
1134         if (!bprm)
1135                 goto out_ret;
1136         memset(bprm, 0, sizeof(*bprm));
1137
1138         file = open_exec(filename);
1139         retval = PTR_ERR(file);
1140         if (IS_ERR(file))
1141                 goto out_kfree;
1142
1143         sched_exec();
1144
1145         bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1146
1147         bprm->file = file;
1148         bprm->filename = filename;
1149         bprm->interp = filename;
1150         bprm->mm = mm_alloc();
1151         retval = -ENOMEM;
1152         if (!bprm->mm)
1153                 goto out_file;
1154
1155         retval = init_new_context(current, bprm->mm);
1156         if (retval < 0)
1157                 goto out_mm;
1158
1159         bprm->argc = count(argv, bprm->p / sizeof(void *));
1160         if ((retval = bprm->argc) < 0)
1161                 goto out_mm;
1162
1163         bprm->envc = count(envp, bprm->p / sizeof(void *));
1164         if ((retval = bprm->envc) < 0)
1165                 goto out_mm;
1166
1167         retval = security_bprm_alloc(bprm);
1168         if (retval)
1169                 goto out;
1170
1171         retval = prepare_binprm(bprm);
1172         if (retval < 0)
1173                 goto out;
1174
1175         retval = copy_strings_kernel(1, &bprm->filename, bprm);
1176         if (retval < 0)
1177                 goto out;
1178
1179         bprm->exec = bprm->p;
1180         retval = copy_strings(bprm->envc, envp, bprm);
1181         if (retval < 0)
1182                 goto out;
1183
1184         retval = copy_strings(bprm->argc, argv, bprm);
1185         if (retval < 0)
1186                 goto out;
1187
1188         retval = search_binary_handler(bprm,regs);
1189         if (retval >= 0) {
1190                 free_arg_pages(bprm);
1191
1192                 /* execve success */
1193                 security_bprm_free(bprm);
1194                 acct_update_integrals();
1195                 update_mem_hiwater();
1196                 kfree(bprm);
1197                 return retval;
1198         }
1199
1200 out:
1201         /* Something went wrong, return the inode and free the argument pages*/
1202         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1203                 struct page * page = bprm->page[i];
1204                 if (page)
1205                         __free_page(page);
1206         }
1207
1208         if (bprm->security)
1209                 security_bprm_free(bprm);
1210
1211 out_mm:
1212         if (bprm->mm)
1213                 mmdrop(bprm->mm);
1214
1215 out_file:
1216         if (bprm->file) {
1217                 allow_write_access(bprm->file);
1218                 fput(bprm->file);
1219         }
1220
1221 out_kfree:
1222         kfree(bprm);
1223
1224 out_ret:
1225         return retval;
1226 }
1227
1228 int set_binfmt(struct linux_binfmt *new)
1229 {
1230         struct linux_binfmt *old = current->binfmt;
1231
1232         if (new) {
1233                 if (!try_module_get(new->module))
1234                         return -1;
1235         }
1236         current->binfmt = new;
1237         if (old)
1238                 module_put(old->module);
1239         return 0;
1240 }
1241
1242 EXPORT_SYMBOL(set_binfmt);
1243
1244 #define CORENAME_MAX_SIZE 64
1245
1246 /* format_corename will inspect the pattern parameter, and output a
1247  * name into corename, which must have space for at least
1248  * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1249  */
1250 static void format_corename(char *corename, const char *pattern, long signr)
1251 {
1252         const char *pat_ptr = pattern;
1253         char *out_ptr = corename;
1254         char *const out_end = corename + CORENAME_MAX_SIZE;
1255         int rc;
1256         int pid_in_pattern = 0;
1257
1258         /* Repeat as long as we have more pattern to process and more output
1259            space */
1260         while (*pat_ptr) {
1261                 if (*pat_ptr != '%') {
1262                         if (out_ptr == out_end)
1263                                 goto out;
1264                         *out_ptr++ = *pat_ptr++;
1265                 } else {
1266                         switch (*++pat_ptr) {
1267                         case 0:
1268                                 goto out;
1269                         /* Double percent, output one percent */
1270                         case '%':
1271                                 if (out_ptr == out_end)
1272                                         goto out;
1273                                 *out_ptr++ = '%';
1274                                 break;
1275                         /* pid */
1276                         case 'p':
1277                                 pid_in_pattern = 1;
1278                                 rc = snprintf(out_ptr, out_end - out_ptr,
1279                                               "%d", current->tgid);
1280                                 if (rc > out_end - out_ptr)
1281                                         goto out;
1282                                 out_ptr += rc;
1283                                 break;
1284                         /* uid */
1285                         case 'u':
1286                                 rc = snprintf(out_ptr, out_end - out_ptr,
1287                                               "%d", current->uid);
1288                                 if (rc > out_end - out_ptr)
1289                                         goto out;
1290                                 out_ptr += rc;
1291                                 break;
1292                         /* gid */
1293                         case 'g':
1294                                 rc = snprintf(out_ptr, out_end - out_ptr,
1295                                               "%d", current->gid);
1296                                 if (rc > out_end - out_ptr)
1297                                         goto out;
1298                                 out_ptr += rc;
1299                                 break;
1300                         /* signal that caused the coredump */
1301                         case 's':
1302                                 rc = snprintf(out_ptr, out_end - out_ptr,
1303                                               "%ld", signr);
1304                                 if (rc > out_end - out_ptr)
1305                                         goto out;
1306                                 out_ptr += rc;
1307                                 break;
1308                         /* UNIX time of coredump */
1309                         case 't': {
1310                                 struct timeval tv;
1311                                 do_gettimeofday(&tv);
1312                                 rc = snprintf(out_ptr, out_end - out_ptr,
1313                                               "%lu", tv.tv_sec);
1314                                 if (rc > out_end - out_ptr)
1315                                         goto out;
1316                                 out_ptr += rc;
1317                                 break;
1318                         }
1319                         /* hostname */
1320                         case 'h':
1321                                 down_read(&uts_sem);
1322                                 rc = snprintf(out_ptr, out_end - out_ptr,
1323                                               "%s", system_utsname.nodename);
1324                                 up_read(&uts_sem);
1325                                 if (rc > out_end - out_ptr)
1326                                         goto out;
1327                                 out_ptr += rc;
1328                                 break;
1329                         /* executable */
1330                         case 'e':
1331                                 rc = snprintf(out_ptr, out_end - out_ptr,
1332                                               "%s", current->comm);
1333                                 if (rc > out_end - out_ptr)
1334                                         goto out;
1335                                 out_ptr += rc;
1336                                 break;
1337                         default:
1338                                 break;
1339                         }
1340                         ++pat_ptr;
1341                 }
1342         }
1343         /* Backward compatibility with core_uses_pid:
1344          *
1345          * If core_pattern does not include a %p (as is the default)
1346          * and core_uses_pid is set, then .%pid will be appended to
1347          * the filename */
1348         if (!pid_in_pattern
1349             && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1350                 rc = snprintf(out_ptr, out_end - out_ptr,
1351                               ".%d", current->tgid);
1352                 if (rc > out_end - out_ptr)
1353                         goto out;
1354                 out_ptr += rc;
1355         }
1356       out:
1357         *out_ptr = 0;
1358 }
1359
1360 static void zap_threads (struct mm_struct *mm)
1361 {
1362         struct task_struct *g, *p;
1363         struct task_struct *tsk = current;
1364         struct completion *vfork_done = tsk->vfork_done;
1365         int traced = 0;
1366
1367         /*
1368          * Make sure nobody is waiting for us to release the VM,
1369          * otherwise we can deadlock when we wait on each other
1370          */
1371         if (vfork_done) {
1372                 tsk->vfork_done = NULL;
1373                 complete(vfork_done);
1374         }
1375
1376         read_lock(&tasklist_lock);
1377         do_each_thread(g,p)
1378                 if (mm == p->mm && p != tsk) {
1379                         force_sig_specific(SIGKILL, p);
1380                         mm->core_waiters++;
1381                         if (unlikely(p->ptrace) &&
1382                             unlikely(p->parent->mm == mm))
1383                                 traced = 1;
1384                 }
1385         while_each_thread(g,p);
1386
1387         read_unlock(&tasklist_lock);
1388
1389         if (unlikely(traced)) {
1390                 /*
1391                  * We are zapping a thread and the thread it ptraces.
1392                  * If the tracee went into a ptrace stop for exit tracing,
1393                  * we could deadlock since the tracer is waiting for this
1394                  * coredump to finish.  Detach them so they can both die.
1395                  */
1396                 write_lock_irq(&tasklist_lock);
1397                 do_each_thread(g,p) {
1398                         if (mm == p->mm && p != tsk &&
1399                             p->ptrace && p->parent->mm == mm) {
1400                                 __ptrace_unlink(p);
1401                         }
1402                 } while_each_thread(g,p);
1403                 write_unlock_irq(&tasklist_lock);
1404         }
1405 }
1406
1407 static void coredump_wait(struct mm_struct *mm)
1408 {
1409         DECLARE_COMPLETION(startup_done);
1410
1411         mm->core_waiters++; /* let other threads block */
1412         mm->core_startup_done = &startup_done;
1413
1414         /* give other threads a chance to run: */
1415         yield();
1416
1417         zap_threads(mm);
1418         if (--mm->core_waiters) {
1419                 up_write(&mm->mmap_sem);
1420                 wait_for_completion(&startup_done);
1421         } else
1422                 up_write(&mm->mmap_sem);
1423         BUG_ON(mm->core_waiters);
1424 }
1425
1426 int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1427 {
1428         char corename[CORENAME_MAX_SIZE + 1];
1429         struct mm_struct *mm = current->mm;
1430         struct linux_binfmt * binfmt;
1431         struct inode * inode;
1432         struct file * file;
1433         int retval = 0;
1434
1435         binfmt = current->binfmt;
1436         if (!binfmt || !binfmt->core_dump)
1437                 goto fail;
1438         down_write(&mm->mmap_sem);
1439         if (!mm->dumpable) {
1440                 up_write(&mm->mmap_sem);
1441                 goto fail;
1442         }
1443         mm->dumpable = 0;
1444         init_completion(&mm->core_done);
1445         spin_lock_irq(&current->sighand->siglock);
1446         current->signal->flags = SIGNAL_GROUP_EXIT;
1447         current->signal->group_exit_code = exit_code;
1448         spin_unlock_irq(&current->sighand->siglock);
1449         coredump_wait(mm);
1450
1451         /*
1452          * Clear any false indication of pending signals that might
1453          * be seen by the filesystem code called to write the core file.
1454          */
1455         current->signal->group_stop_count = 0;
1456         clear_thread_flag(TIF_SIGPENDING);
1457
1458         if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1459                 goto fail_unlock;
1460
1461         /*
1462          * lock_kernel() because format_corename() is controlled by sysctl, which
1463          * uses lock_kernel()
1464          */
1465         lock_kernel();
1466         format_corename(corename, core_pattern, signr);
1467         unlock_kernel();
1468         file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE, 0600);
1469         if (IS_ERR(file))
1470                 goto fail_unlock;
1471         inode = file->f_dentry->d_inode;
1472         if (inode->i_nlink > 1)
1473                 goto close_fail;        /* multiple links - don't dump */
1474         if (d_unhashed(file->f_dentry))
1475                 goto close_fail;
1476
1477         if (!S_ISREG(inode->i_mode))
1478                 goto close_fail;
1479         if (!file->f_op)
1480                 goto close_fail;
1481         if (!file->f_op->write)
1482                 goto close_fail;
1483         if (do_truncate(file->f_dentry, 0) != 0)
1484                 goto close_fail;
1485
1486         retval = binfmt->core_dump(signr, regs, file);
1487
1488         if (retval)
1489                 current->signal->group_exit_code |= 0x80;
1490 close_fail:
1491         filp_close(file, NULL);
1492 fail_unlock:
1493         complete_all(&mm->core_done);
1494 fail:
1495         return retval;
1496 }