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/slab.h>
  26 #include <linux/file.h>
  27 #include <linux/mman.h>
  28 #include <linux/a.out.h>
  29 #include <linux/stat.h>
  30 #include <linux/fcntl.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/init.h>
  33 #include <linux/pagemap.h>
  34 #include <linux/highmem.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/key.h>
  37 #include <linux/personality.h>
  38 #include <linux/binfmts.h>
  39 #include <linux/swap.h>
  40 #include <linux/utsname.h>
  41 #include <linux/module.h>
  42 #include <linux/namei.h>
  43 #include <linux/proc_fs.h>
  44 #include <linux/ptrace.h>
  45 #include <linux/mount.h>
  46 #include <linux/security.h>
  47 #include <linux/syscalls.h>
  48 #include <linux/rmap.h>
  49 #include <linux/acct.h>
  50 #include <linux/cn_proc.h>
  51 #include <linux/audit.h>
  52
  53 #include <asm/uaccess.h>
  54 #include <asm/mmu_context.h>
  55
  56 #ifdef CONFIG_KMOD
  57 #include <linux/kmod.h>
  58 #endif
  59
  60 int core_uses_pid;
  61 char core_pattern[65] = "core";
  62 int suid_dumpable = 0;
  63
  64 EXPORT_SYMBOL(suid_dumpable);
  65 /* The maximal length of core_pattern is also specified in sysctl.c */
  66
  67 static struct linux_binfmt *formats;
  68 static DEFINE_RWLOCK(binfmt_lock);
  69
  70 int register_binfmt(struct linux_binfmt * fmt)
  71 {
  72         struct linux_binfmt ** tmp = &formats;
  73
  74         if (!fmt)
  75                 return -EINVAL;
  76         if (fmt->next)
  77                 return -EBUSY;
  78         write_lock(&binfmt_lock);
  79         while (*tmp) {
  80                 if (fmt == *tmp) {
  81                         write_unlock(&binfmt_lock);
  82                         return -EBUSY;
  83                 }
  84                 tmp = &(*tmp)->next;
  85         }
  86         fmt->next = formats;
  87         formats = fmt;
  88         write_unlock(&binfmt_lock);
  89         return 0;
  90 }
  91
  92 EXPORT_SYMBOL(register_binfmt);
  93
  94 int unregister_binfmt(struct linux_binfmt * fmt)
  95 {
  96         struct linux_binfmt ** tmp = &formats;
  97
  98         write_lock(&binfmt_lock);
  99         while (*tmp) {
 100                 if (fmt == *tmp) {
 101                         *tmp = fmt->next;
 102                         write_unlock(&binfmt_lock);
 103                         return 0;
 104                 }
 105                 tmp = &(*tmp)->next;
 106         }
 107         write_unlock(&binfmt_lock);
 108         return -EINVAL;
 109 }
 110
 111 EXPORT_SYMBOL(unregister_binfmt);
 112
 113 static inline void put_binfmt(struct linux_binfmt * fmt)
 114 {
 115         module_put(fmt->module);
 116 }
 117
 118 /*
 119  * Note that a shared library must be both readable and executable due to
 120  * security reasons.
 121  *
 122  * Also note that we take the address to load from from the file itself.
 123  */
 124 asmlinkage long sys_uselib(const char __user * library)
 125 {
 126         struct file * file;
 127         struct nameidata nd;
 128         int error;
 129
 130         error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
 131         if (error)
 132                 goto out;
 133
 134         error = -EINVAL;
 135         if (!S_ISREG(nd.dentry->d_inode->i_mode))
 136                 goto exit;
 137
 138         error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
 139         if (error)
 140                 goto exit;
 141
 142         file = nameidata_to_filp(&nd, O_RDONLY);
 143         error = PTR_ERR(file);
 144         if (IS_ERR(file))
 145                 goto out;
 146
 147         error = -ENOEXEC;
 148         if(file->f_op) {
 149                 struct linux_binfmt * fmt;
 150
 151                 read_lock(&binfmt_lock);
 152                 for (fmt = formats ; fmt ; fmt = fmt->next) {
 153                         if (!fmt->load_shlib)
 154                                 continue;
 155                         if (!try_module_get(fmt->module))
 156                                 continue;
 157                         read_unlock(&binfmt_lock);
 158                         error = fmt->load_shlib(file);
 159                         read_lock(&binfmt_lock);
 160                         put_binfmt(fmt);
 161                         if (error != -ENOEXEC)
 162                                 break;
 163                 }
 164                 read_unlock(&binfmt_lock);
 165         }
 166         fput(file);
 167 out:
 168         return error;
 169 exit:
 170         release_open_intent(&nd);
 171         path_release(&nd);
 172         goto out;
 173 }
 174
 175 /*
 176  * count() counts the number of strings in array ARGV.
 177  */
 178 static int count(char __user * __user * argv, int max)
 179 {
 180         int i = 0;
 181
 182         if (argv != NULL) {
 183                 for (;;) {
 184                         char __user * p;
 185
 186                         if (get_user(p, argv))
 187                                 return -EFAULT;
 188                         if (!p)
 189                                 break;
 190                         argv++;
 191                         if(++i > max)
 192                                 return -E2BIG;
 193                         cond_resched();
 194                 }
 195         }
 196         return i;
 197 }
 198
 199 /*
 200  * 'copy_strings()' copies argument/environment strings from user
 201  * memory to free pages in kernel mem. These are in a format ready
 202  * to be put directly into the top of new user memory.
 203  */
 204 static int copy_strings(int argc, char __user * __user * argv,
 205                         struct linux_binprm *bprm)
 206 {
 207         struct page *kmapped_page = NULL;
 208         char *kaddr = NULL;
 209         int ret;
 210
 211         while (argc-- > 0) {
 212                 char __user *str;
 213                 int len;
 214                 unsigned long pos;
 215
 216                 if (get_user(str, argv+argc) ||
 217                                 !(len = strnlen_user(str, bprm->p))) {
 218                         ret = -EFAULT;
 219                         goto out;
 220                 }
 221
 222                 if (bprm->p < len)  {
 223                         ret = -E2BIG;
 224                         goto out;
 225                 }
 226
 227                 bprm->p -= len;
 228                 /* XXX: add architecture specific overflow check here. */
 229                 pos = bprm->p;
 230
 231                 while (len > 0) {
 232                         int i, new, err;
 233                         int offset, bytes_to_copy;
 234                         struct page *page;
 235
 236                         offset = pos % PAGE_SIZE;
 237                         i = pos/PAGE_SIZE;
 238                         page = bprm->page[i];
 239                         new = 0;
 240                         if (!page) {
 241                                 page = alloc_page(GFP_HIGHUSER);
 242                                 bprm->page[i] = page;
 243                                 if (!page) {
 244                                         ret = -ENOMEM;
 245                                         goto out;
 246                                 }
 247                                 new = 1;
 248                         }
 249
 250                         if (page != kmapped_page) {
 251                                 if (kmapped_page)
 252                                         kunmap(kmapped_page);
 253                                 kmapped_page = page;
 254                                 kaddr = kmap(kmapped_page);
 255                         }
 256                         if (new && offset)
 257                                 memset(kaddr, 0, offset);
 258                         bytes_to_copy = PAGE_SIZE - offset;
 259                         if (bytes_to_copy > len) {
 260                                 bytes_to_copy = len;
 261                                 if (new)
 262                                         memset(kaddr+offset+len, 0,
 263                                                 PAGE_SIZE-offset-len);
 264                         }
 265                         err = copy_from_user(kaddr+offset, str, bytes_to_copy);
 266                         if (err) {
 267                                 ret = -EFAULT;
 268                                 goto out;
 269                         }
 270
 271                         pos += bytes_to_copy;
 272                         str += bytes_to_copy;
 273                         len -= bytes_to_copy;
 274                 }
 275         }
 276         ret = 0;
 277 out:
 278         if (kmapped_page)
 279                 kunmap(kmapped_page);
 280         return ret;
 281 }
 282
 283 /*
 284  * Like copy_strings, but get argv and its values from kernel memory.
 285  */
 286 int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
 287 {
 288         int r;
 289         mm_segment_t oldfs = get_fs();
 290         set_fs(KERNEL_DS);
 291         r = copy_strings(argc, (char __user * __user *)argv, bprm);
 292         set_fs(oldfs);
 293         return r;
 294 }
 295
 296 EXPORT_SYMBOL(copy_strings_kernel);
 297
 298 #ifdef CONFIG_MMU
 299 /*
 300  * This routine is used to map in a page into an address space: needed by
 301  * execve() for the initial stack and environment pages.
 302  *
 303  * vma->vm_mm->mmap_sem is held for writing.
 304  */
 305 void install_arg_page(struct vm_area_struct *vma,
 306                         struct page *page, unsigned long address)
 307 {
 308         struct mm_struct *mm = vma->vm_mm;
 309         pte_t * pte;
 310         spinlock_t *ptl;
 311
 312         if (unlikely(anon_vma_prepare(vma)))
 313                 goto out;
 314
 315         flush_dcache_page(page);
 316         pte = get_locked_pte(mm, address, &ptl);
 317         if (!pte)
 318                 goto out;
 319         if (!pte_none(*pte)) {
 320                 pte_unmap_unlock(pte, ptl);
 321                 goto out;
 322         }
 323         inc_mm_counter(mm, anon_rss);
 324         lru_cache_add_active(page);
 325         set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
 326                                         page, vma->vm_page_prot))));
 327         page_add_new_anon_rmap(page, vma, address);
 328         pte_unmap_unlock(pte, ptl);
 329
 330         /* no need for flush_tlb */
 331         return;
 332 out:
 333         __free_page(page);
 334         force_sig(SIGKILL, current);
 335 }
 336
 337 #define EXTRA_STACK_VM_PAGES    20      /* random */
 338
 339 int setup_arg_pages(struct linux_binprm *bprm,
 340                     unsigned long stack_top,
 341                     int executable_stack)
 342 {
 343         unsigned long stack_base;
 344         struct vm_area_struct *mpnt;
 345         struct mm_struct *mm = current->mm;
 346         int i, ret;
 347         long arg_size;
 348
 349 #ifdef CONFIG_STACK_GROWSUP
 350         /* Move the argument and environment strings to the bottom of the
 351          * stack space.
 352          */
 353         int offset, j;
 354         char *to, *from;
 355
 356         /* Start by shifting all the pages down */
 357         i = 0;
 358         for (j = 0; j < MAX_ARG_PAGES; j++) {
 359                 struct page *page = bprm->page[j];
 360                 if (!page)
 361                         continue;
 362                 bprm->page[i++] = page;
 363         }
 364
 365         /* Now move them within their pages */
 366         offset = bprm->p % PAGE_SIZE;
 367         to = kmap(bprm->page[0]);
 368         for (j = 1; j < i; j++) {
 369                 memmove(to, to + offset, PAGE_SIZE - offset);
 370                 from = kmap(bprm->page[j]);
 371                 memcpy(to + PAGE_SIZE - offset, from, offset);
 372                 kunmap(bprm->page[j - 1]);
 373                 to = from;
 374         }
 375         memmove(to, to + offset, PAGE_SIZE - offset);
 376         kunmap(bprm->page[j - 1]);
 377
 378         /* Limit stack size to 1GB */
 379         stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
 380         if (stack_base > (1 << 30))
 381                 stack_base = 1 << 30;
 382         stack_base = PAGE_ALIGN(stack_top - stack_base);
 383
 384         /* Adjust bprm->p to point to the end of the strings. */
 385         bprm->p = stack_base + PAGE_SIZE * i - offset;
 386
 387         mm->arg_start = stack_base;
 388         arg_size = i << PAGE_SHIFT;
 389
 390         /* zero pages that were copied above */
 391         while (i < MAX_ARG_PAGES)
 392                 bprm->page[i++] = NULL;
 393 #else
 394         stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
 395         stack_base = PAGE_ALIGN(stack_base);
 396         bprm->p += stack_base;
 397         mm->arg_start = bprm->p;
 398         arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
 399 #endif
 400
 401         arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
 402
 403         if (bprm->loader)
 404                 bprm->loader += stack_base;
 405         bprm->exec += stack_base;
 406
 407         mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 408         if (!mpnt)
 409                 return -ENOMEM;
 410
 411         memset(mpnt, 0, sizeof(*mpnt));
 412
 413         down_write(&mm->mmap_sem);
 414         {
 415                 mpnt->vm_mm = mm;
 416 #ifdef CONFIG_STACK_GROWSUP
 417                 mpnt->vm_start = stack_base;
 418                 mpnt->vm_end = stack_base + arg_size;
 419 #else
 420                 mpnt->vm_end = stack_top;
 421                 mpnt->vm_start = mpnt->vm_end - arg_size;
 422 #endif
 423                 /* Adjust stack execute permissions; explicitly enable
 424                  * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
 425                  * and leave alone (arch default) otherwise. */
 426                 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
 427                         mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
 428                 else if (executable_stack == EXSTACK_DISABLE_X)
 429                         mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
 430                 else
 431                         mpnt->vm_flags = VM_STACK_FLAGS;
 432                 mpnt->vm_flags |= mm->def_flags;
 433                 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
 434                 if ((ret = insert_vm_struct(mm, mpnt))) {
 435                         up_write(&mm->mmap_sem);
 436                         kmem_cache_free(vm_area_cachep, mpnt);
 437                         return ret;
 438                 }
 439                 mm->stack_vm = mm->total_vm = vma_pages(mpnt);
 440         }
 441
 442         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
 443                 struct page *page = bprm->page[i];
 444                 if (page) {
 445                         bprm->page[i] = NULL;
 446                         install_arg_page(mpnt, page, stack_base);
 447                 }
 448                 stack_base += PAGE_SIZE;
 449         }
 450         up_write(&mm->mmap_sem);
 451
 452         return 0;
 453 }
 454
 455 EXPORT_SYMBOL(setup_arg_pages);
 456
 457 #define free_arg_pages(bprm) do { } while (0)
 458
 459 #else
 460
 461 static inline void free_arg_pages(struct linux_binprm *bprm)
 462 {
 463         int i;
 464
 465         for (i = 0; i < MAX_ARG_PAGES; i++) {
 466                 if (bprm->page[i])
 467                         __free_page(bprm->page[i]);
 468                 bprm->page[i] = NULL;
 469         }
 470 }
 471
 472 #endif /* CONFIG_MMU */
 473
 474 struct file *open_exec(const char *name)
 475 {
 476         struct nameidata nd;
 477         int err;
 478         struct file *file;
 479
 480         err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
 481         file = ERR_PTR(err);
 482
 483         if (!err) {
 484                 struct inode *inode = nd.dentry->d_inode;
 485                 file = ERR_PTR(-EACCES);
 486                 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
 487                     S_ISREG(inode->i_mode)) {
 488                         int err = vfs_permission(&nd, MAY_EXEC);
 489                         if (!err && !(inode->i_mode & 0111))
 490                                 err = -EACCES;
 491                         file = ERR_PTR(err);
 492                         if (!err) {
 493                                 file = nameidata_to_filp(&nd, O_RDONLY);
 494                                 if (!IS_ERR(file)) {
 495                                         err = deny_write_access(file);
 496                                         if (err) {
 497                                                 fput(file);
 498                                                 file = ERR_PTR(err);
 499                                         }
 500                                 }
 501 out:
 502                                 return file;
 503                         }
 504                 }
 505                 release_open_intent(&nd);
 506                 path_release(&nd);
 507         }
 508         goto out;
 509 }
 510
 511 EXPORT_SYMBOL(open_exec);
 512
 513 int kernel_read(struct file *file, unsigned long offset,
 514         char *addr, unsigned long count)
 515 {
 516         mm_segment_t old_fs;
 517         loff_t pos = offset;
 518         int result;
 519
 520         old_fs = get_fs();
 521         set_fs(get_ds());
 522         /* The cast to a user pointer is valid due to the set_fs() */
 523         result = vfs_read(file, (void __user *)addr, count, &pos);
 524         set_fs(old_fs);
 525         return result;
 526 }
 527
 528 EXPORT_SYMBOL(kernel_read);
 529
 530 static int exec_mmap(struct mm_struct *mm)
 531 {
 532         struct task_struct *tsk;
 533         struct mm_struct * old_mm, *active_mm;
 534
 535         /* Notify parent that we're no longer interested in the old VM */
 536         tsk = current;
 537         old_mm = current->mm;
 538         mm_release(tsk, old_mm);
 539
 540         if (old_mm) {
 541                 /*
 542                  * Make sure that if there is a core dump in progress
 543                  * for the old mm, we get out and die instead of going
 544                  * through with the exec.  We must hold mmap_sem around
 545                  * checking core_waiters and changing tsk->mm.  The
 546                  * core-inducing thread will increment core_waiters for
 547                  * each thread whose ->mm == old_mm.
 548                  */
 549                 down_read(&old_mm->mmap_sem);
 550                 if (unlikely(old_mm->core_waiters)) {
 551                         up_read(&old_mm->mmap_sem);
 552                         return -EINTR;
 553                 }
 554         }
 555         task_lock(tsk);
 556         active_mm = tsk->active_mm;
 557         tsk->mm = mm;
 558         tsk->active_mm = mm;
 559         activate_mm(active_mm, mm);
 560         task_unlock(tsk);
 561         arch_pick_mmap_layout(mm);
 562         if (old_mm) {
 563                 up_read(&old_mm->mmap_sem);
 564                 BUG_ON(active_mm != old_mm);
 565                 mmput(old_mm);
 566                 return 0;
 567         }
 568         mmdrop(active_mm);
 569         return 0;
 570 }
 571
 572 /*
 573  * This function makes sure the current process has its own signal table,
 574  * so that flush_signal_handlers can later reset the handlers without
 575  * disturbing other processes.  (Other processes might share the signal
 576  * table via the CLONE_SIGHAND option to clone().)
 577  */
 578 static int de_thread(struct task_struct *tsk)
 579 {
 580         struct signal_struct *sig = tsk->signal;
 581         struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
 582         spinlock_t *lock = &oldsighand->siglock;
 583         struct task_struct *leader = NULL;
 584         int count;
 585
 586         /*
 587          * If we don't share sighandlers, then we aren't sharing anything
 588          * and we can just re-use it all.
 589          */
 590         if (atomic_read(&oldsighand->count) <= 1) {
 591                 BUG_ON(atomic_read(&sig->count) != 1);
 592                 exit_itimers(sig);
 593                 return 0;
 594         }
 595
 596         newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
 597         if (!newsighand)
 598                 return -ENOMEM;
 599
 600         if (thread_group_empty(current))
 601                 goto no_thread_group;
 602
 603         /*
 604          * Kill all other threads in the thread group.
 605          * We must hold tasklist_lock to call zap_other_threads.
 606          */
 607         read_lock(&tasklist_lock);
 608         spin_lock_irq(lock);
 609         if (sig->flags & SIGNAL_GROUP_EXIT) {
 610                 /*
 611                  * Another group action in progress, just
 612                  * return so that the signal is processed.
 613                  */
 614                 spin_unlock_irq(lock);
 615                 read_unlock(&tasklist_lock);
 616                 kmem_cache_free(sighand_cachep, newsighand);
 617                 return -EAGAIN;
 618         }
 619
 620         /*
 621          * child_reaper ignores SIGKILL, change it now.
 622          * Reparenting needs write_lock on tasklist_lock,
 623          * so it is safe to do it under read_lock.
 624          */
 625         if (unlikely(current->group_leader == child_reaper))
 626                 child_reaper = current;
 627
 628         zap_other_threads(current);
 629         read_unlock(&tasklist_lock);
 630
 631         /*
 632          * Account for the thread group leader hanging around:
 633          */
 634         count = 1;
 635         if (!thread_group_leader(current)) {
 636                 count = 2;
 637                 /*
 638                  * The SIGALRM timer survives the exec, but needs to point
 639                  * at us as the new group leader now.  We have a race with
 640                  * a timer firing now getting the old leader, so we need to
 641                  * synchronize with any firing (by calling del_timer_sync)
 642                  * before we can safely let the old group leader die.
 643                  */
 644                 sig->tsk = current;
 645                 spin_unlock_irq(lock);
 646                 if (hrtimer_cancel(&sig->real_timer))
 647                         hrtimer_restart(&sig->real_timer);
 648                 spin_lock_irq(lock);
 649         }
 650         while (atomic_read(&sig->count) > count) {
 651                 sig->group_exit_task = current;
 652                 sig->notify_count = count;
 653                 __set_current_state(TASK_UNINTERRUPTIBLE);
 654                 spin_unlock_irq(lock);
 655                 schedule();
 656                 spin_lock_irq(lock);
 657         }
 658         sig->group_exit_task = NULL;
 659         sig->notify_count = 0;
 660         spin_unlock_irq(lock);
 661
 662         /*
 663          * At this point all other threads have exited, all we have to
 664          * do is to wait for the thread group leader to become inactive,
 665          * and to assume its PID:
 666          */
 667         if (!thread_group_leader(current)) {
 668                 /*
 669                  * Wait for the thread group leader to be a zombie.
 670                  * It should already be zombie at this point, most
 671                  * of the time.
 672                  */
 673                 leader = current->group_leader;
 674                 while (leader->exit_state != EXIT_ZOMBIE)
 675                         yield();
 676
 677                 /*
 678                  * The only record we have of the real-time age of a
 679                  * process, regardless of execs it's done, is start_time.
 680                  * All the past CPU time is accumulated in signal_struct
 681                  * from sister threads now dead.  But in this non-leader
 682                  * exec, nothing survives from the original leader thread,
 683                  * whose birth marks the true age of this process now.
 684                  * When we take on its identity by switching to its PID, we
 685                  * also take its birthdate (always earlier than our own).
 686                  */
 687                 current->start_time = leader->start_time;
 688
 689                 write_lock_irq(&tasklist_lock);
 690
 691                 BUG_ON(leader->tgid != current->tgid);
 692                 BUG_ON(current->pid == current->tgid);
 693                 /*
 694                  * An exec() starts a new thread group with the
 695                  * TGID of the previous thread group. Rehash the
 696                  * two threads with a switched PID, and release
 697                  * the former thread group leader:
 698                  */
 699
 700                 /* Become a process group leader with the old leader's pid.
 701                  * Note: The old leader also uses thispid until release_task
 702                  *       is called.  Odd but simple and correct.
 703                  */
 704                 detach_pid(current, PIDTYPE_PID);
 705                 current->pid = leader->pid;
 706                 attach_pid(current, PIDTYPE_PID,  current->pid);
 707                 attach_pid(current, PIDTYPE_PGID, current->signal->pgrp);
 708                 attach_pid(current, PIDTYPE_SID,  current->signal->session);
 709                 list_replace_rcu(&leader->tasks, &current->tasks);
 710
 711                 current->group_leader = current;
 712                 leader->group_leader = current;
 713
 714                 /* Reduce leader to a thread */
 715                 detach_pid(leader, PIDTYPE_PGID);
 716                 detach_pid(leader, PIDTYPE_SID);
 717
 718                 current->exit_signal = SIGCHLD;
 719
 720                 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
 721                 leader->exit_state = EXIT_DEAD;
 722
 723                 write_unlock_irq(&tasklist_lock);
 724         }
 725
 726         /*
 727          * There may be one thread left which is just exiting,
 728          * but it's safe to stop telling the group to kill themselves.
 729          */
 730         sig->flags = 0;
 731
 732 no_thread_group:
 733         exit_itimers(sig);
 734         if (leader)
 735                 release_task(leader);
 736
 737         BUG_ON(atomic_read(&sig->count) != 1);
 738
 739         if (atomic_read(&oldsighand->count) == 1) {
 740                 /*
 741                  * Now that we nuked the rest of the thread group,
 742                  * it turns out we are not sharing sighand any more either.
 743                  * So we can just keep it.
 744                  */
 745                 kmem_cache_free(sighand_cachep, newsighand);
 746         } else {
 747                 /*
 748                  * Move our state over to newsighand and switch it in.
 749                  */
 750                 atomic_set(&newsighand->count, 1);
 751                 memcpy(newsighand->action, oldsighand->action,
 752                        sizeof(newsighand->action));
 753
 754                 write_lock_irq(&tasklist_lock);
 755                 spin_lock(&oldsighand->siglock);
 756                 spin_lock(&newsighand->siglock);
 757
 758                 rcu_assign_pointer(current->sighand, newsighand);
 759                 recalc_sigpending();
 760
 761                 spin_unlock(&newsighand->siglock);
 762                 spin_unlock(&oldsighand->siglock);
 763                 write_unlock_irq(&tasklist_lock);
 764
 765                 if (atomic_dec_and_test(&oldsighand->count))
 766                         kmem_cache_free(sighand_cachep, oldsighand);
 767         }
 768
 769         BUG_ON(!thread_group_leader(current));
 770         return 0;
 771 }
 772
 773 /*
 774  * These functions flushes out all traces of the currently running executable
 775  * so that a new one can be started
 776  */
 777
 778 static void flush_old_files(struct files_struct * files)
 779 {
 780         long j = -1;
 781         struct fdtable *fdt;
 782
 783         spin_lock(&files->file_lock);
 784         for (;;) {
 785                 unsigned long set, i;
 786
 787                 j++;
 788                 i = j * __NFDBITS;
 789                 fdt = files_fdtable(files);
 790                 if (i >= fdt->max_fds || i >= fdt->max_fdset)
 791                         break;
 792                 set = fdt->close_on_exec->fds_bits[j];
 793                 if (!set)
 794                         continue;
 795                 fdt->close_on_exec->fds_bits[j] = 0;
 796                 spin_unlock(&files->file_lock);
 797                 for ( ; set ; i++,set >>= 1) {
 798                         if (set & 1) {
 799                                 sys_close(i);
 800                         }
 801                 }
 802                 spin_lock(&files->file_lock);
 803
 804         }
 805         spin_unlock(&files->file_lock);
 806 }
 807
 808 void get_task_comm(char *buf, struct task_struct *tsk)
 809 {
 810         /* buf must be at least sizeof(tsk->comm) in size */
 811         task_lock(tsk);
 812         strncpy(buf, tsk->comm, sizeof(tsk->comm));
 813         task_unlock(tsk);
 814 }
 815
 816 void set_task_comm(struct task_struct *tsk, char *buf)
 817 {
 818         task_lock(tsk);
 819         strlcpy(tsk->comm, buf, sizeof(tsk->comm));
 820         task_unlock(tsk);
 821 }
 822
 823 int flush_old_exec(struct linux_binprm * bprm)
 824 {
 825         char * name;
 826         int i, ch, retval;
 827         struct files_struct *files;
 828         char tcomm[sizeof(current->comm)];
 829
 830         /*
 831          * Make sure we have a private signal table and that
 832          * we are unassociated from the previous thread group.
 833          */
 834         retval = de_thread(current);
 835         if (retval)
 836                 goto out;
 837
 838         /*
 839          * Make sure we have private file handles. Ask the
 840          * fork helper to do the work for us and the exit
 841          * helper to do the cleanup of the old one.
 842          */
 843         files = current->files;         /* refcounted so safe to hold */
 844         retval = unshare_files();
 845         if (retval)
 846                 goto out;
 847         /*
 848          * Release all of the old mmap stuff
 849          */
 850         retval = exec_mmap(bprm->mm);
 851         if (retval)
 852                 goto mmap_failed;
 853
 854         bprm->mm = NULL;                /* We're using it now */
 855
 856         /* This is the point of no return */
 857         put_files_struct(files);
 858
 859         current->sas_ss_sp = current->sas_ss_size = 0;
 860
 861         if (current->euid == current->uid && current->egid == current->gid)
 862                 current->mm->dumpable = 1;
 863         else
 864                 current->mm->dumpable = suid_dumpable;
 865
 866         name = bprm->filename;
 867
 868         /* Copies the binary name from after last slash */
 869         for (i=0; (ch = *(name++)) != '\0';) {
 870                 if (ch == '/')
 871                         i = 0; /* overwrite what we wrote */
 872                 else
 873                         if (i < (sizeof(tcomm) - 1))
 874                                 tcomm[i++] = ch;
 875         }
 876         tcomm[i] = '\0';
 877         set_task_comm(current, tcomm);
 878
 879         current->flags &= ~PF_RANDOMIZE;
 880         flush_thread();
 881
 882         /* Set the new mm task size. We have to do that late because it may
 883          * depend on TIF_32BIT which is only updated in flush_thread() on
 884          * some architectures like powerpc
 885          */
 886         current->mm->task_size = TASK_SIZE;
 887
 888         if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
 889             file_permission(bprm->file, MAY_READ) ||
 890             (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
 891                 suid_keys(current);
 892                 current->mm->dumpable = suid_dumpable;
 893         }
 894
 895         /* An exec changes our domain. We are no longer part of the thread
 896            group */
 897
 898         current->self_exec_id++;
 899
 900         flush_signal_handlers(current, 0);
 901         flush_old_files(current->files);
 902
 903         return 0;
 904
 905 mmap_failed:
 906         put_files_struct(current->files);
 907         current->files = files;
 908 out:
 909         return retval;
 910 }
 911
 912 EXPORT_SYMBOL(flush_old_exec);
 913
 914 /*
 915  * Fill the binprm structure from the inode.
 916  * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
 917  */
 918 int prepare_binprm(struct linux_binprm *bprm)
 919 {
 920         int mode;
 921         struct inode * inode = bprm->file->f_dentry->d_inode;
 922         int retval;
 923
 924         mode = inode->i_mode;
 925         /*
 926          * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
 927          * generic_permission lets a non-executable through
 928          */
 929         if (!(mode & 0111))     /* with at least _one_ execute bit set */
 930                 return -EACCES;
 931         if (bprm->file->f_op == NULL)
 932                 return -EACCES;
 933
 934         bprm->e_uid = current->euid;
 935         bprm->e_gid = current->egid;
 936
 937         if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) {
 938                 /* Set-uid? */
 939                 if (mode & S_ISUID) {
 940                         current->personality &= ~PER_CLEAR_ON_SETID;
 941                         bprm->e_uid = inode->i_uid;
 942                 }
 943
 944                 /* Set-gid? */
 945                 /*
 946                  * If setgid is set but no group execute bit then this
 947                  * is a candidate for mandatory locking, not a setgid
 948                  * executable.
 949                  */
 950                 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
 951                         current->personality &= ~PER_CLEAR_ON_SETID;
 952                         bprm->e_gid = inode->i_gid;
 953                 }
 954         }
 955
 956         /* fill in binprm security blob */
 957         retval = security_bprm_set(bprm);
 958         if (retval)
 959                 return retval;
 960
 961         memset(bprm->buf,0,BINPRM_BUF_SIZE);
 962         return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
 963 }
 964
 965 EXPORT_SYMBOL(prepare_binprm);
 966
 967 static int unsafe_exec(struct task_struct *p)
 968 {
 969         int unsafe = 0;
 970         if (p->ptrace & PT_PTRACED) {
 971                 if (p->ptrace & PT_PTRACE_CAP)
 972                         unsafe |= LSM_UNSAFE_PTRACE_CAP;
 973                 else
 974                         unsafe |= LSM_UNSAFE_PTRACE;
 975         }
 976         if (atomic_read(&p->fs->count) > 1 ||
 977             atomic_read(&p->files->count) > 1 ||
 978             atomic_read(&p->sighand->count) > 1)
 979                 unsafe |= LSM_UNSAFE_SHARE;
 980
 981         return unsafe;
 982 }
 983
 984 void compute_creds(struct linux_binprm *bprm)
 985 {
 986         int unsafe;
 987
 988         if (bprm->e_uid != current->uid)
 989                 suid_keys(current);
 990         exec_keys(current);
 991
 992         task_lock(current);
 993         unsafe = unsafe_exec(current);
 994         security_bprm_apply_creds(bprm, unsafe);
 995         task_unlock(current);
 996         security_bprm_post_apply_creds(bprm);
 997 }
 998
 999 EXPORT_SYMBOL(compute_creds);
1000
1001 void remove_arg_zero(struct linux_binprm *bprm)
1002 {
1003         if (bprm->argc) {
1004                 unsigned long offset;
1005                 char * kaddr;
1006                 struct page *page;
1007
1008                 offset = bprm->p % PAGE_SIZE;
1009                 goto inside;
1010
1011                 while (bprm->p++, *(kaddr+offset++)) {
1012                         if (offset != PAGE_SIZE)
1013                                 continue;
1014                         offset = 0;
1015                         kunmap_atomic(kaddr, KM_USER0);
1016 inside:
1017                         page = bprm->page[bprm->p/PAGE_SIZE];
1018                         kaddr = kmap_atomic(page, KM_USER0);
1019                 }
1020                 kunmap_atomic(kaddr, KM_USER0);
1021                 bprm->argc--;
1022         }
1023 }
1024
1025 EXPORT_SYMBOL(remove_arg_zero);
1026
1027 /*
1028  * cycle the list of binary formats handler, until one recognizes the image
1029  */
1030 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1031 {
1032         int try,retval;
1033         struct linux_binfmt *fmt;
1034 #ifdef __alpha__
1035         /* handle /sbin/loader.. */
1036         {
1037             struct exec * eh = (struct exec *) bprm->buf;
1038
1039             if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1040                 (eh->fh.f_flags & 0x3000) == 0x3000)
1041             {
1042                 struct file * file;
1043                 unsigned long loader;
1044
1045                 allow_write_access(bprm->file);
1046                 fput(bprm->file);
1047                 bprm->file = NULL;
1048
1049                 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1050
1051                 file = open_exec("/sbin/loader");
1052                 retval = PTR_ERR(file);
1053                 if (IS_ERR(file))
1054                         return retval;
1055
1056                 /* Remember if the application is TASO.  */
1057                 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1058
1059                 bprm->file = file;
1060                 bprm->loader = loader;
1061                 retval = prepare_binprm(bprm);
1062                 if (retval<0)
1063                         return retval;
1064                 /* should call search_binary_handler recursively here,
1065                    but it does not matter */
1066             }
1067         }
1068 #endif
1069         retval = security_bprm_check(bprm);
1070         if (retval)
1071                 return retval;
1072
1073         /* kernel module loader fixup */
1074         /* so we don't try to load run modprobe in kernel space. */
1075         set_fs(USER_DS);
1076
1077         retval = audit_bprm(bprm);
1078         if (retval)
1079                 return retval;
1080
1081         retval = -ENOENT;
1082         for (try=0; try<2; try++) {
1083                 read_lock(&binfmt_lock);
1084                 for (fmt = formats ; fmt ; fmt = fmt->next) {
1085                         int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1086                         if (!fn)
1087                                 continue;
1088                         if (!try_module_get(fmt->module))
1089                                 continue;
1090                         read_unlock(&binfmt_lock);
1091                         retval = fn(bprm, regs);
1092                         if (retval >= 0) {
1093                                 put_binfmt(fmt);
1094                                 allow_write_access(bprm->file);
1095                                 if (bprm->file)
1096                                         fput(bprm->file);
1097                                 bprm->file = NULL;
1098                                 current->did_exec = 1;
1099                                 proc_exec_connector(current);
1100                                 return retval;
1101                         }
1102                         read_lock(&binfmt_lock);
1103                         put_binfmt(fmt);
1104                         if (retval != -ENOEXEC || bprm->mm == NULL)
1105                                 break;
1106                         if (!bprm->file) {
1107                                 read_unlock(&binfmt_lock);
1108                                 return retval;
1109                         }
1110                 }
1111                 read_unlock(&binfmt_lock);
1112                 if (retval != -ENOEXEC || bprm->mm == NULL) {
1113                         break;
1114 #ifdef CONFIG_KMOD
1115                 }else{
1116 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1117                         if (printable(bprm->buf[0]) &&
1118                             printable(bprm->buf[1]) &&
1119                             printable(bprm->buf[2]) &&
1120                             printable(bprm->buf[3]))
1121                                 break; /* -ENOEXEC */
1122                         request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1123 #endif
1124                 }
1125         }
1126         return retval;
1127 }
1128
1129 EXPORT_SYMBOL(search_binary_handler);
1130
1131 /*
1132  * sys_execve() executes a new program.
1133  */
1134 int do_execve(char * filename,
1135         char __user *__user *argv,
1136         char __user *__user *envp,
1137         struct pt_regs * regs)
1138 {
1139         struct linux_binprm *bprm;
1140         struct file *file;
1141         int retval;
1142         int i;
1143
1144         retval = -ENOMEM;
1145         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1146         if (!bprm)
1147                 goto out_ret;
1148
1149         file = open_exec(filename);
1150         retval = PTR_ERR(file);
1151         if (IS_ERR(file))
1152                 goto out_kfree;
1153
1154         sched_exec();
1155
1156         bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1157
1158         bprm->file = file;
1159         bprm->filename = filename;
1160         bprm->interp = filename;
1161         bprm->mm = mm_alloc();
1162         retval = -ENOMEM;
1163         if (!bprm->mm)
1164                 goto out_file;
1165
1166         retval = init_new_context(current, bprm->mm);
1167         if (retval < 0)
1168                 goto out_mm;
1169
1170         bprm->argc = count(argv, bprm->p / sizeof(void *));
1171         if ((retval = bprm->argc) < 0)
1172                 goto out_mm;
1173
1174         bprm->envc = count(envp, bprm->p / sizeof(void *));
1175         if ((retval = bprm->envc) < 0)
1176                 goto out_mm;
1177
1178         retval = security_bprm_alloc(bprm);
1179         if (retval)
1180                 goto out;
1181
1182         retval = prepare_binprm(bprm);
1183         if (retval < 0)
1184                 goto out;
1185
1186         retval = copy_strings_kernel(1, &bprm->filename, bprm);
1187         if (retval < 0)
1188                 goto out;
1189
1190         bprm->exec = bprm->p;
1191         retval = copy_strings(bprm->envc, envp, bprm);
1192         if (retval < 0)
1193                 goto out;
1194
1195         retval = copy_strings(bprm->argc, argv, bprm);
1196         if (retval < 0)
1197                 goto out;
1198
1199         retval = search_binary_handler(bprm,regs);
1200         if (retval >= 0) {
1201                 free_arg_pages(bprm);
1202
1203                 /* execve success */
1204                 security_bprm_free(bprm);
1205                 acct_update_integrals(current);
1206                 kfree(bprm);
1207                 return retval;
1208         }
1209
1210 out:
1211         /* Something went wrong, return the inode and free the argument pages*/
1212         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1213                 struct page * page = bprm->page[i];
1214                 if (page)
1215                         __free_page(page);
1216         }
1217
1218         if (bprm->security)
1219                 security_bprm_free(bprm);
1220
1221 out_mm:
1222         if (bprm->mm)
1223                 mmdrop(bprm->mm);
1224
1225 out_file:
1226         if (bprm->file) {
1227                 allow_write_access(bprm->file);
1228                 fput(bprm->file);
1229         }
1230
1231 out_kfree:
1232         kfree(bprm);
1233
1234 out_ret:
1235         return retval;
1236 }
1237
1238 int set_binfmt(struct linux_binfmt *new)
1239 {
1240         struct linux_binfmt *old = current->binfmt;
1241
1242         if (new) {
1243                 if (!try_module_get(new->module))
1244                         return -1;
1245         }
1246         current->binfmt = new;
1247         if (old)
1248                 module_put(old->module);
1249         return 0;
1250 }
1251
1252 EXPORT_SYMBOL(set_binfmt);
1253
1254 #define CORENAME_MAX_SIZE 64
1255
1256 /* format_corename will inspect the pattern parameter, and output a
1257  * name into corename, which must have space for at least
1258  * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1259  */
1260 static void format_corename(char *corename, const char *pattern, long signr)
1261 {
1262         const char *pat_ptr = pattern;
1263         char *out_ptr = corename;
1264         char *const out_end = corename + CORENAME_MAX_SIZE;
1265         int rc;
1266         int pid_in_pattern = 0;
1267
1268         /* Repeat as long as we have more pattern to process and more output
1269            space */
1270         while (*pat_ptr) {
1271                 if (*pat_ptr != '%') {
1272                         if (out_ptr == out_end)
1273                                 goto out;
1274                         *out_ptr++ = *pat_ptr++;
1275                 } else {
1276                         switch (*++pat_ptr) {
1277                         case 0:
1278                                 goto out;
1279                         /* Double percent, output one percent */
1280                         case '%':
1281                                 if (out_ptr == out_end)
1282                                         goto out;
1283                                 *out_ptr++ = '%';
1284                                 break;
1285                         /* pid */
1286                         case 'p':
1287                                 pid_in_pattern = 1;
1288                                 rc = snprintf(out_ptr, out_end - out_ptr,
1289                                               "%d", current->tgid);
1290                                 if (rc > out_end - out_ptr)
1291                                         goto out;
1292                                 out_ptr += rc;
1293                                 break;
1294                         /* uid */
1295                         case 'u':
1296                                 rc = snprintf(out_ptr, out_end - out_ptr,
1297                                               "%d", current->uid);
1298                                 if (rc > out_end - out_ptr)
1299                                         goto out;
1300                                 out_ptr += rc;
1301                                 break;
1302                         /* gid */
1303                         case 'g':
1304                                 rc = snprintf(out_ptr, out_end - out_ptr,
1305                                               "%d", current->gid);
1306                                 if (rc > out_end - out_ptr)
1307                                         goto out;
1308                                 out_ptr += rc;
1309                                 break;
1310                         /* signal that caused the coredump */
1311                         case 's':
1312                                 rc = snprintf(out_ptr, out_end - out_ptr,
1313                                               "%ld", signr);
1314                                 if (rc > out_end - out_ptr)
1315                                         goto out;
1316                                 out_ptr += rc;
1317                                 break;
1318                         /* UNIX time of coredump */
1319                         case 't': {
1320                                 struct timeval tv;
1321                                 do_gettimeofday(&tv);
1322                                 rc = snprintf(out_ptr, out_end - out_ptr,
1323                                               "%lu", tv.tv_sec);
1324                                 if (rc > out_end - out_ptr)
1325                                         goto out;
1326                                 out_ptr += rc;
1327                                 break;
1328                         }
1329                         /* hostname */
1330                         case 'h':
1331                                 down_read(&uts_sem);
1332                                 rc = snprintf(out_ptr, out_end - out_ptr,
1333                                               "%s", system_utsname.nodename);
1334                                 up_read(&uts_sem);
1335                                 if (rc > out_end - out_ptr)
1336                                         goto out;
1337                                 out_ptr += rc;
1338                                 break;
1339                         /* executable */
1340                         case 'e':
1341                                 rc = snprintf(out_ptr, out_end - out_ptr,
1342                                               "%s", current->comm);
1343                                 if (rc > out_end - out_ptr)
1344                                         goto out;
1345                                 out_ptr += rc;
1346                                 break;
1347                         default:
1348                                 break;
1349                         }
1350                         ++pat_ptr;
1351                 }
1352         }
1353         /* Backward compatibility with core_uses_pid:
1354          *
1355          * If core_pattern does not include a %p (as is the default)
1356          * and core_uses_pid is set, then .%pid will be appended to
1357          * the filename */
1358         if (!pid_in_pattern
1359             && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1360                 rc = snprintf(out_ptr, out_end - out_ptr,
1361                               ".%d", current->tgid);
1362                 if (rc > out_end - out_ptr)
1363                         goto out;
1364                 out_ptr += rc;
1365         }
1366       out:
1367         *out_ptr = 0;
1368 }
1369
1370 static void zap_process(struct task_struct *start)
1371 {
1372         struct task_struct *t;
1373
1374         start->signal->flags = SIGNAL_GROUP_EXIT;
1375         start->signal->group_stop_count = 0;
1376
1377         t = start;
1378         do {
1379                 if (t != current && t->mm) {
1380                         t->mm->core_waiters++;
1381                         sigaddset(&t->pending.signal, SIGKILL);
1382                         signal_wake_up(t, 1);
1383                 }
1384         } while ((t = next_thread(t)) != start);
1385 }
1386
1387 static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
1388                                 int exit_code)
1389 {
1390         struct task_struct *g, *p;
1391         unsigned long flags;
1392         int err = -EAGAIN;
1393
1394         spin_lock_irq(&tsk->sighand->siglock);
1395         if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
1396                 tsk->signal->group_exit_code = exit_code;
1397                 zap_process(tsk);
1398                 err = 0;
1399         }
1400         spin_unlock_irq(&tsk->sighand->siglock);
1401         if (err)
1402                 return err;
1403
1404         if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
1405                 goto done;
1406
1407         rcu_read_lock();
1408         for_each_process(g) {
1409                 if (g == tsk->group_leader)
1410                         continue;
1411
1412                 p = g;
1413                 do {
1414                         if (p->mm) {
1415                                 if (p->mm == mm) {
1416                                         /*
1417                                          * p->sighand can't disappear, but
1418                                          * may be changed by de_thread()
1419                                          */
1420                                         lock_task_sighand(p, &flags);
1421                                         zap_process(p);
1422                                         unlock_task_sighand(p, &flags);
1423                                 }
1424                                 break;
1425                         }
1426                 } while ((p = next_thread(p)) != g);
1427         }
1428         rcu_read_unlock();
1429 done:
1430         return mm->core_waiters;
1431 }
1432
1433 static int coredump_wait(int exit_code)
1434 {
1435         struct task_struct *tsk = current;
1436         struct mm_struct *mm = tsk->mm;
1437         struct completion startup_done;
1438         struct completion *vfork_done;
1439         int core_waiters;
1440
1441         init_completion(&mm->core_done);
1442         init_completion(&startup_done);
1443         mm->core_startup_done = &startup_done;
1444
1445         core_waiters = zap_threads(tsk, mm, exit_code);
1446         up_write(&mm->mmap_sem);
1447
1448         if (unlikely(core_waiters < 0))
1449                 goto fail;
1450
1451         /*
1452          * Make sure nobody is waiting for us to release the VM,
1453          * otherwise we can deadlock when we wait on each other
1454          */
1455         vfork_done = tsk->vfork_done;
1456         if (vfork_done) {
1457                 tsk->vfork_done = NULL;
1458                 complete(vfork_done);
1459         }
1460
1461         if (core_waiters)
1462                 wait_for_completion(&startup_done);
1463 fail:
1464         BUG_ON(mm->core_waiters);
1465         return core_waiters;
1466 }
1467
1468 int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1469 {
1470         char corename[CORENAME_MAX_SIZE + 1];
1471         struct mm_struct *mm = current->mm;
1472         struct linux_binfmt * binfmt;
1473         struct inode * inode;
1474         struct file * file;
1475         int retval = 0;
1476         int fsuid = current->fsuid;
1477         int flag = 0;
1478
1479         binfmt = current->binfmt;
1480         if (!binfmt || !binfmt->core_dump)
1481                 goto fail;
1482         down_write(&mm->mmap_sem);
1483         if (!mm->dumpable) {
1484                 up_write(&mm->mmap_sem);
1485                 goto fail;
1486         }
1487
1488         /*
1489          *      We cannot trust fsuid as being the "true" uid of the
1490          *      process nor do we know its entire history. We only know it
1491          *      was tainted so we dump it as root in mode 2.
1492          */
1493         if (mm->dumpable == 2) {        /* Setuid core dump mode */
1494                 flag = O_EXCL;          /* Stop rewrite attacks */
1495                 current->fsuid = 0;     /* Dump root private */
1496         }
1497         mm->dumpable = 0;
1498
1499         retval = coredump_wait(exit_code);
1500         if (retval < 0)
1501                 goto fail;
1502
1503         /*
1504          * Clear any false indication of pending signals that might
1505          * be seen by the filesystem code called to write the core file.
1506          */
1507         clear_thread_flag(TIF_SIGPENDING);
1508
1509         if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1510                 goto fail_unlock;
1511
1512         /*
1513          * lock_kernel() because format_corename() is controlled by sysctl, which
1514          * uses lock_kernel()
1515          */
1516         lock_kernel();
1517         format_corename(corename, core_pattern, signr);
1518         unlock_kernel();
1519         file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600);
1520         if (IS_ERR(file))
1521                 goto fail_unlock;
1522         inode = file->f_dentry->d_inode;
1523         if (inode->i_nlink > 1)
1524                 goto close_fail;        /* multiple links - don't dump */
1525         if (d_unhashed(file->f_dentry))
1526                 goto close_fail;
1527
1528         if (!S_ISREG(inode->i_mode))
1529                 goto close_fail;
1530         if (!file->f_op)
1531                 goto close_fail;
1532         if (!file->f_op->write)
1533                 goto close_fail;
1534         if (do_truncate(file->f_dentry, 0, 0, file) != 0)
1535                 goto close_fail;
1536
1537         retval = binfmt->core_dump(signr, regs, file);
1538
1539         if (retval)
1540                 current->signal->group_exit_code |= 0x80;
1541 close_fail:
1542         filp_close(file, NULL);
1543 fail_unlock:
1544         current->fsuid = fsuid;
1545         complete_all(&mm->core_done);
1546 fail:
1547         return retval;
1548 }