[PATCH] Char: timers cleanup
[linux-2.6] / 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/pid_namespace.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/tsacct_kern.h>
51 #include <linux/cn_proc.h>
52 #include <linux/audit.h>
53
54 #include <asm/uaccess.h>
55 #include <asm/mmu_context.h>
56
57 #ifdef CONFIG_KMOD
58 #include <linux/kmod.h>
59 #endif
60
61 int core_uses_pid;
62 char core_pattern[128] = "core";
63 int suid_dumpable = 0;
64
65 EXPORT_SYMBOL(suid_dumpable);
66 /* The maximal length of core_pattern is also specified in sysctl.c */
67
68 static struct linux_binfmt *formats;
69 static DEFINE_RWLOCK(binfmt_lock);
70
71 int register_binfmt(struct linux_binfmt * fmt)
72 {
73         struct linux_binfmt ** tmp = &formats;
74
75         if (!fmt)
76                 return -EINVAL;
77         if (fmt->next)
78                 return -EBUSY;
79         write_lock(&binfmt_lock);
80         while (*tmp) {
81                 if (fmt == *tmp) {
82                         write_unlock(&binfmt_lock);
83                         return -EBUSY;
84                 }
85                 tmp = &(*tmp)->next;
86         }
87         fmt->next = formats;
88         formats = fmt;
89         write_unlock(&binfmt_lock);
90         return 0;       
91 }
92
93 EXPORT_SYMBOL(register_binfmt);
94
95 int unregister_binfmt(struct linux_binfmt * fmt)
96 {
97         struct linux_binfmt ** tmp = &formats;
98
99         write_lock(&binfmt_lock);
100         while (*tmp) {
101                 if (fmt == *tmp) {
102                         *tmp = fmt->next;
103                         write_unlock(&binfmt_lock);
104                         return 0;
105                 }
106                 tmp = &(*tmp)->next;
107         }
108         write_unlock(&binfmt_lock);
109         return -EINVAL;
110 }
111
112 EXPORT_SYMBOL(unregister_binfmt);
113
114 static inline void put_binfmt(struct linux_binfmt * fmt)
115 {
116         module_put(fmt->module);
117 }
118
119 /*
120  * Note that a shared library must be both readable and executable due to
121  * security reasons.
122  *
123  * Also note that we take the address to load from from the file itself.
124  */
125 asmlinkage long sys_uselib(const char __user * library)
126 {
127         struct file * file;
128         struct nameidata nd;
129         int error;
130
131         error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
132         if (error)
133                 goto out;
134
135         error = -EINVAL;
136         if (!S_ISREG(nd.dentry->d_inode->i_mode))
137                 goto exit;
138
139         error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
140         if (error)
141                 goto exit;
142
143         file = nameidata_to_filp(&nd, O_RDONLY);
144         error = PTR_ERR(file);
145         if (IS_ERR(file))
146                 goto out;
147
148         error = -ENOEXEC;
149         if(file->f_op) {
150                 struct linux_binfmt * fmt;
151
152                 read_lock(&binfmt_lock);
153                 for (fmt = formats ; fmt ; fmt = fmt->next) {
154                         if (!fmt->load_shlib)
155                                 continue;
156                         if (!try_module_get(fmt->module))
157                                 continue;
158                         read_unlock(&binfmt_lock);
159                         error = fmt->load_shlib(file);
160                         read_lock(&binfmt_lock);
161                         put_binfmt(fmt);
162                         if (error != -ENOEXEC)
163                                 break;
164                 }
165                 read_unlock(&binfmt_lock);
166         }
167         fput(file);
168 out:
169         return error;
170 exit:
171         release_open_intent(&nd);
172         path_release(&nd);
173         goto out;
174 }
175
176 /*
177  * count() counts the number of strings in array ARGV.
178  */
179 static int count(char __user * __user * argv, int max)
180 {
181         int i = 0;
182
183         if (argv != NULL) {
184                 for (;;) {
185                         char __user * p;
186
187                         if (get_user(p, argv))
188                                 return -EFAULT;
189                         if (!p)
190                                 break;
191                         argv++;
192                         if(++i > max)
193                                 return -E2BIG;
194                         cond_resched();
195                 }
196         }
197         return i;
198 }
199
200 /*
201  * 'copy_strings()' copies argument/environment strings from user
202  * memory to free pages in kernel mem. These are in a format ready
203  * to be put directly into the top of new user memory.
204  */
205 static int copy_strings(int argc, char __user * __user * argv,
206                         struct linux_binprm *bprm)
207 {
208         struct page *kmapped_page = NULL;
209         char *kaddr = NULL;
210         int ret;
211
212         while (argc-- > 0) {
213                 char __user *str;
214                 int len;
215                 unsigned long pos;
216
217                 if (get_user(str, argv+argc) ||
218                                 !(len = strnlen_user(str, bprm->p))) {
219                         ret = -EFAULT;
220                         goto out;
221                 }
222
223                 if (bprm->p < len)  {
224                         ret = -E2BIG;
225                         goto out;
226                 }
227
228                 bprm->p -= len;
229                 /* XXX: add architecture specific overflow check here. */
230                 pos = bprm->p;
231
232                 while (len > 0) {
233                         int i, new, err;
234                         int offset, bytes_to_copy;
235                         struct page *page;
236
237                         offset = pos % PAGE_SIZE;
238                         i = pos/PAGE_SIZE;
239                         page = bprm->page[i];
240                         new = 0;
241                         if (!page) {
242                                 page = alloc_page(GFP_HIGHUSER);
243                                 bprm->page[i] = page;
244                                 if (!page) {
245                                         ret = -ENOMEM;
246                                         goto out;
247                                 }
248                                 new = 1;
249                         }
250
251                         if (page != kmapped_page) {
252                                 if (kmapped_page)
253                                         kunmap(kmapped_page);
254                                 kmapped_page = page;
255                                 kaddr = kmap(kmapped_page);
256                         }
257                         if (new && offset)
258                                 memset(kaddr, 0, offset);
259                         bytes_to_copy = PAGE_SIZE - offset;
260                         if (bytes_to_copy > len) {
261                                 bytes_to_copy = len;
262                                 if (new)
263                                         memset(kaddr+offset+len, 0,
264                                                 PAGE_SIZE-offset-len);
265                         }
266                         err = copy_from_user(kaddr+offset, str, bytes_to_copy);
267                         if (err) {
268                                 ret = -EFAULT;
269                                 goto out;
270                         }
271
272                         pos += bytes_to_copy;
273                         str += bytes_to_copy;
274                         len -= bytes_to_copy;
275                 }
276         }
277         ret = 0;
278 out:
279         if (kmapped_page)
280                 kunmap(kmapped_page);
281         return ret;
282 }
283
284 /*
285  * Like copy_strings, but get argv and its values from kernel memory.
286  */
287 int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
288 {
289         int r;
290         mm_segment_t oldfs = get_fs();
291         set_fs(KERNEL_DS);
292         r = copy_strings(argc, (char __user * __user *)argv, bprm);
293         set_fs(oldfs);
294         return r;
295 }
296
297 EXPORT_SYMBOL(copy_strings_kernel);
298
299 #ifdef CONFIG_MMU
300 /*
301  * This routine is used to map in a page into an address space: needed by
302  * execve() for the initial stack and environment pages.
303  *
304  * vma->vm_mm->mmap_sem is held for writing.
305  */
306 void install_arg_page(struct vm_area_struct *vma,
307                         struct page *page, unsigned long address)
308 {
309         struct mm_struct *mm = vma->vm_mm;
310         pte_t * pte;
311         spinlock_t *ptl;
312
313         if (unlikely(anon_vma_prepare(vma)))
314                 goto out;
315
316         flush_dcache_page(page);
317         pte = get_locked_pte(mm, address, &ptl);
318         if (!pte)
319                 goto out;
320         if (!pte_none(*pte)) {
321                 pte_unmap_unlock(pte, ptl);
322                 goto out;
323         }
324         inc_mm_counter(mm, anon_rss);
325         lru_cache_add_active(page);
326         set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
327                                         page, vma->vm_page_prot))));
328         page_add_new_anon_rmap(page, vma, address);
329         pte_unmap_unlock(pte, ptl);
330
331         /* no need for flush_tlb */
332         return;
333 out:
334         __free_page(page);
335         force_sig(SIGKILL, current);
336 }
337
338 #define EXTRA_STACK_VM_PAGES    20      /* random */
339
340 int setup_arg_pages(struct linux_binprm *bprm,
341                     unsigned long stack_top,
342                     int executable_stack)
343 {
344         unsigned long stack_base;
345         struct vm_area_struct *mpnt;
346         struct mm_struct *mm = current->mm;
347         int i, ret;
348         long arg_size;
349
350 #ifdef CONFIG_STACK_GROWSUP
351         /* Move the argument and environment strings to the bottom of the
352          * stack space.
353          */
354         int offset, j;
355         char *to, *from;
356
357         /* Start by shifting all the pages down */
358         i = 0;
359         for (j = 0; j < MAX_ARG_PAGES; j++) {
360                 struct page *page = bprm->page[j];
361                 if (!page)
362                         continue;
363                 bprm->page[i++] = page;
364         }
365
366         /* Now move them within their pages */
367         offset = bprm->p % PAGE_SIZE;
368         to = kmap(bprm->page[0]);
369         for (j = 1; j < i; j++) {
370                 memmove(to, to + offset, PAGE_SIZE - offset);
371                 from = kmap(bprm->page[j]);
372                 memcpy(to + PAGE_SIZE - offset, from, offset);
373                 kunmap(bprm->page[j - 1]);
374                 to = from;
375         }
376         memmove(to, to + offset, PAGE_SIZE - offset);
377         kunmap(bprm->page[j - 1]);
378
379         /* Limit stack size to 1GB */
380         stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
381         if (stack_base > (1 << 30))
382                 stack_base = 1 << 30;
383         stack_base = PAGE_ALIGN(stack_top - stack_base);
384
385         /* Adjust bprm->p to point to the end of the strings. */
386         bprm->p = stack_base + PAGE_SIZE * i - offset;
387
388         mm->arg_start = stack_base;
389         arg_size = i << PAGE_SHIFT;
390
391         /* zero pages that were copied above */
392         while (i < MAX_ARG_PAGES)
393                 bprm->page[i++] = NULL;
394 #else
395         stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
396         stack_base = PAGE_ALIGN(stack_base);
397         bprm->p += stack_base;
398         mm->arg_start = bprm->p;
399         arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
400 #endif
401
402         arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
403
404         if (bprm->loader)
405                 bprm->loader += stack_base;
406         bprm->exec += stack_base;
407
408         mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
409         if (!mpnt)
410                 return -ENOMEM;
411
412         down_write(&mm->mmap_sem);
413         {
414                 mpnt->vm_mm = mm;
415 #ifdef CONFIG_STACK_GROWSUP
416                 mpnt->vm_start = stack_base;
417                 mpnt->vm_end = stack_base + arg_size;
418 #else
419                 mpnt->vm_end = stack_top;
420                 mpnt->vm_start = mpnt->vm_end - arg_size;
421 #endif
422                 /* Adjust stack execute permissions; explicitly enable
423                  * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
424                  * and leave alone (arch default) otherwise. */
425                 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
426                         mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
427                 else if (executable_stack == EXSTACK_DISABLE_X)
428                         mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
429                 else
430                         mpnt->vm_flags = VM_STACK_FLAGS;
431                 mpnt->vm_flags |= mm->def_flags;
432                 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
433                 if ((ret = insert_vm_struct(mm, mpnt))) {
434                         up_write(&mm->mmap_sem);
435                         kmem_cache_free(vm_area_cachep, mpnt);
436                         return ret;
437                 }
438                 mm->stack_vm = mm->total_vm = vma_pages(mpnt);
439         }
440
441         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
442                 struct page *page = bprm->page[i];
443                 if (page) {
444                         bprm->page[i] = NULL;
445                         install_arg_page(mpnt, page, stack_base);
446                 }
447                 stack_base += PAGE_SIZE;
448         }
449         up_write(&mm->mmap_sem);
450         
451         return 0;
452 }
453
454 EXPORT_SYMBOL(setup_arg_pages);
455
456 #define free_arg_pages(bprm) do { } while (0)
457
458 #else
459
460 static inline void free_arg_pages(struct linux_binprm *bprm)
461 {
462         int i;
463
464         for (i = 0; i < MAX_ARG_PAGES; i++) {
465                 if (bprm->page[i])
466                         __free_page(bprm->page[i]);
467                 bprm->page[i] = NULL;
468         }
469 }
470
471 #endif /* CONFIG_MMU */
472
473 struct file *open_exec(const char *name)
474 {
475         struct nameidata nd;
476         int err;
477         struct file *file;
478
479         err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
480         file = ERR_PTR(err);
481
482         if (!err) {
483                 struct inode *inode = nd.dentry->d_inode;
484                 file = ERR_PTR(-EACCES);
485                 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
486                     S_ISREG(inode->i_mode)) {
487                         int err = vfs_permission(&nd, MAY_EXEC);
488                         file = ERR_PTR(err);
489                         if (!err) {
490                                 file = nameidata_to_filp(&nd, O_RDONLY);
491                                 if (!IS_ERR(file)) {
492                                         err = deny_write_access(file);
493                                         if (err) {
494                                                 fput(file);
495                                                 file = ERR_PTR(err);
496                                         }
497                                 }
498 out:
499                                 return file;
500                         }
501                 }
502                 release_open_intent(&nd);
503                 path_release(&nd);
504         }
505         goto out;
506 }
507
508 EXPORT_SYMBOL(open_exec);
509
510 int kernel_read(struct file *file, unsigned long offset,
511         char *addr, unsigned long count)
512 {
513         mm_segment_t old_fs;
514         loff_t pos = offset;
515         int result;
516
517         old_fs = get_fs();
518         set_fs(get_ds());
519         /* The cast to a user pointer is valid due to the set_fs() */
520         result = vfs_read(file, (void __user *)addr, count, &pos);
521         set_fs(old_fs);
522         return result;
523 }
524
525 EXPORT_SYMBOL(kernel_read);
526
527 static int exec_mmap(struct mm_struct *mm)
528 {
529         struct task_struct *tsk;
530         struct mm_struct * old_mm, *active_mm;
531
532         /* Notify parent that we're no longer interested in the old VM */
533         tsk = current;
534         old_mm = current->mm;
535         mm_release(tsk, old_mm);
536
537         if (old_mm) {
538                 /*
539                  * Make sure that if there is a core dump in progress
540                  * for the old mm, we get out and die instead of going
541                  * through with the exec.  We must hold mmap_sem around
542                  * checking core_waiters and changing tsk->mm.  The
543                  * core-inducing thread will increment core_waiters for
544                  * each thread whose ->mm == old_mm.
545                  */
546                 down_read(&old_mm->mmap_sem);
547                 if (unlikely(old_mm->core_waiters)) {
548                         up_read(&old_mm->mmap_sem);
549                         return -EINTR;
550                 }
551         }
552         task_lock(tsk);
553         active_mm = tsk->active_mm;
554         tsk->mm = mm;
555         tsk->active_mm = mm;
556         activate_mm(active_mm, mm);
557         task_unlock(tsk);
558         arch_pick_mmap_layout(mm);
559         if (old_mm) {
560                 up_read(&old_mm->mmap_sem);
561                 BUG_ON(active_mm != old_mm);
562                 mmput(old_mm);
563                 return 0;
564         }
565         mmdrop(active_mm);
566         return 0;
567 }
568
569 /*
570  * This function makes sure the current process has its own signal table,
571  * so that flush_signal_handlers can later reset the handlers without
572  * disturbing other processes.  (Other processes might share the signal
573  * table via the CLONE_SIGHAND option to clone().)
574  */
575 static int de_thread(struct task_struct *tsk)
576 {
577         struct signal_struct *sig = tsk->signal;
578         struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
579         spinlock_t *lock = &oldsighand->siglock;
580         struct task_struct *leader = NULL;
581         int count;
582
583         /*
584          * If we don't share sighandlers, then we aren't sharing anything
585          * and we can just re-use it all.
586          */
587         if (atomic_read(&oldsighand->count) <= 1) {
588                 BUG_ON(atomic_read(&sig->count) != 1);
589                 exit_itimers(sig);
590                 return 0;
591         }
592
593         newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
594         if (!newsighand)
595                 return -ENOMEM;
596
597         if (thread_group_empty(tsk))
598                 goto no_thread_group;
599
600         /*
601          * Kill all other threads in the thread group.
602          * We must hold tasklist_lock to call zap_other_threads.
603          */
604         read_lock(&tasklist_lock);
605         spin_lock_irq(lock);
606         if (sig->flags & SIGNAL_GROUP_EXIT) {
607                 /*
608                  * Another group action in progress, just
609                  * return so that the signal is processed.
610                  */
611                 spin_unlock_irq(lock);
612                 read_unlock(&tasklist_lock);
613                 kmem_cache_free(sighand_cachep, newsighand);
614                 return -EAGAIN;
615         }
616
617         /*
618          * child_reaper ignores SIGKILL, change it now.
619          * Reparenting needs write_lock on tasklist_lock,
620          * so it is safe to do it under read_lock.
621          */
622         if (unlikely(tsk->group_leader == child_reaper(tsk)))
623                 tsk->nsproxy->pid_ns->child_reaper = tsk;
624
625         zap_other_threads(tsk);
626         read_unlock(&tasklist_lock);
627
628         /*
629          * Account for the thread group leader hanging around:
630          */
631         count = 1;
632         if (!thread_group_leader(tsk)) {
633                 count = 2;
634                 /*
635                  * The SIGALRM timer survives the exec, but needs to point
636                  * at us as the new group leader now.  We have a race with
637                  * a timer firing now getting the old leader, so we need to
638                  * synchronize with any firing (by calling del_timer_sync)
639                  * before we can safely let the old group leader die.
640                  */
641                 sig->tsk = tsk;
642                 spin_unlock_irq(lock);
643                 if (hrtimer_cancel(&sig->real_timer))
644                         hrtimer_restart(&sig->real_timer);
645                 spin_lock_irq(lock);
646         }
647         while (atomic_read(&sig->count) > count) {
648                 sig->group_exit_task = tsk;
649                 sig->notify_count = count;
650                 __set_current_state(TASK_UNINTERRUPTIBLE);
651                 spin_unlock_irq(lock);
652                 schedule();
653                 spin_lock_irq(lock);
654         }
655         sig->group_exit_task = NULL;
656         sig->notify_count = 0;
657         spin_unlock_irq(lock);
658
659         /*
660          * At this point all other threads have exited, all we have to
661          * do is to wait for the thread group leader to become inactive,
662          * and to assume its PID:
663          */
664         if (!thread_group_leader(tsk)) {
665                 /*
666                  * Wait for the thread group leader to be a zombie.
667                  * It should already be zombie at this point, most
668                  * of the time.
669                  */
670                 leader = tsk->group_leader;
671                 while (leader->exit_state != EXIT_ZOMBIE)
672                         yield();
673
674                 /*
675                  * The only record we have of the real-time age of a
676                  * process, regardless of execs it's done, is start_time.
677                  * All the past CPU time is accumulated in signal_struct
678                  * from sister threads now dead.  But in this non-leader
679                  * exec, nothing survives from the original leader thread,
680                  * whose birth marks the true age of this process now.
681                  * When we take on its identity by switching to its PID, we
682                  * also take its birthdate (always earlier than our own).
683                  */
684                 tsk->start_time = leader->start_time;
685
686                 write_lock_irq(&tasklist_lock);
687
688                 BUG_ON(leader->tgid != tsk->tgid);
689                 BUG_ON(tsk->pid == tsk->tgid);
690                 /*
691                  * An exec() starts a new thread group with the
692                  * TGID of the previous thread group. Rehash the
693                  * two threads with a switched PID, and release
694                  * the former thread group leader:
695                  */
696
697                 /* Become a process group leader with the old leader's pid.
698                  * The old leader becomes a thread of the this thread group.
699                  * Note: The old leader also uses this pid until release_task
700                  *       is called.  Odd but simple and correct.
701                  */
702                 detach_pid(tsk, PIDTYPE_PID);
703                 tsk->pid = leader->pid;
704                 attach_pid(tsk, PIDTYPE_PID,  tsk->pid);
705                 transfer_pid(leader, tsk, PIDTYPE_PGID);
706                 transfer_pid(leader, tsk, PIDTYPE_SID);
707                 list_replace_rcu(&leader->tasks, &tsk->tasks);
708
709                 tsk->group_leader = tsk;
710                 leader->group_leader = tsk;
711
712                 tsk->exit_signal = SIGCHLD;
713
714                 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
715                 leader->exit_state = EXIT_DEAD;
716
717                 write_unlock_irq(&tasklist_lock);
718         }
719
720         /*
721          * There may be one thread left which is just exiting,
722          * but it's safe to stop telling the group to kill themselves.
723          */
724         sig->flags = 0;
725
726 no_thread_group:
727         exit_itimers(sig);
728         if (leader)
729                 release_task(leader);
730
731         BUG_ON(atomic_read(&sig->count) != 1);
732
733         if (atomic_read(&oldsighand->count) == 1) {
734                 /*
735                  * Now that we nuked the rest of the thread group,
736                  * it turns out we are not sharing sighand any more either.
737                  * So we can just keep it.
738                  */
739                 kmem_cache_free(sighand_cachep, newsighand);
740         } else {
741                 /*
742                  * Move our state over to newsighand and switch it in.
743                  */
744                 atomic_set(&newsighand->count, 1);
745                 memcpy(newsighand->action, oldsighand->action,
746                        sizeof(newsighand->action));
747
748                 write_lock_irq(&tasklist_lock);
749                 spin_lock(&oldsighand->siglock);
750                 spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);
751
752                 rcu_assign_pointer(tsk->sighand, newsighand);
753                 recalc_sigpending();
754
755                 spin_unlock(&newsighand->siglock);
756                 spin_unlock(&oldsighand->siglock);
757                 write_unlock_irq(&tasklist_lock);
758
759                 if (atomic_dec_and_test(&oldsighand->count))
760                         kmem_cache_free(sighand_cachep, oldsighand);
761         }
762
763         BUG_ON(!thread_group_leader(tsk));
764         return 0;
765 }
766         
767 /*
768  * These functions flushes out all traces of the currently running executable
769  * so that a new one can be started
770  */
771
772 static void flush_old_files(struct files_struct * files)
773 {
774         long j = -1;
775         struct fdtable *fdt;
776
777         spin_lock(&files->file_lock);
778         for (;;) {
779                 unsigned long set, i;
780
781                 j++;
782                 i = j * __NFDBITS;
783                 fdt = files_fdtable(files);
784                 if (i >= fdt->max_fds)
785                         break;
786                 set = fdt->close_on_exec->fds_bits[j];
787                 if (!set)
788                         continue;
789                 fdt->close_on_exec->fds_bits[j] = 0;
790                 spin_unlock(&files->file_lock);
791                 for ( ; set ; i++,set >>= 1) {
792                         if (set & 1) {
793                                 sys_close(i);
794                         }
795                 }
796                 spin_lock(&files->file_lock);
797
798         }
799         spin_unlock(&files->file_lock);
800 }
801
802 void get_task_comm(char *buf, struct task_struct *tsk)
803 {
804         /* buf must be at least sizeof(tsk->comm) in size */
805         task_lock(tsk);
806         strncpy(buf, tsk->comm, sizeof(tsk->comm));
807         task_unlock(tsk);
808 }
809
810 void set_task_comm(struct task_struct *tsk, char *buf)
811 {
812         task_lock(tsk);
813         strlcpy(tsk->comm, buf, sizeof(tsk->comm));
814         task_unlock(tsk);
815 }
816
817 int flush_old_exec(struct linux_binprm * bprm)
818 {
819         char * name;
820         int i, ch, retval;
821         struct files_struct *files;
822         char tcomm[sizeof(current->comm)];
823
824         /*
825          * Make sure we have a private signal table and that
826          * we are unassociated from the previous thread group.
827          */
828         retval = de_thread(current);
829         if (retval)
830                 goto out;
831
832         /*
833          * Make sure we have private file handles. Ask the
834          * fork helper to do the work for us and the exit
835          * helper to do the cleanup of the old one.
836          */
837         files = current->files;         /* refcounted so safe to hold */
838         retval = unshare_files();
839         if (retval)
840                 goto out;
841         /*
842          * Release all of the old mmap stuff
843          */
844         retval = exec_mmap(bprm->mm);
845         if (retval)
846                 goto mmap_failed;
847
848         bprm->mm = NULL;                /* We're using it now */
849
850         /* This is the point of no return */
851         put_files_struct(files);
852
853         current->sas_ss_sp = current->sas_ss_size = 0;
854
855         if (current->euid == current->uid && current->egid == current->gid)
856                 current->mm->dumpable = 1;
857         else
858                 current->mm->dumpable = suid_dumpable;
859
860         name = bprm->filename;
861
862         /* Copies the binary name from after last slash */
863         for (i=0; (ch = *(name++)) != '\0';) {
864                 if (ch == '/')
865                         i = 0; /* overwrite what we wrote */
866                 else
867                         if (i < (sizeof(tcomm) - 1))
868                                 tcomm[i++] = ch;
869         }
870         tcomm[i] = '\0';
871         set_task_comm(current, tcomm);
872
873         current->flags &= ~PF_RANDOMIZE;
874         flush_thread();
875
876         /* Set the new mm task size. We have to do that late because it may
877          * depend on TIF_32BIT which is only updated in flush_thread() on
878          * some architectures like powerpc
879          */
880         current->mm->task_size = TASK_SIZE;
881
882         if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || 
883             file_permission(bprm->file, MAY_READ) ||
884             (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
885                 suid_keys(current);
886                 current->mm->dumpable = suid_dumpable;
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         reset_files_struct(current, files);
901 out:
902         return retval;
903 }
904
905 EXPORT_SYMBOL(flush_old_exec);
906
907 /* 
908  * Fill the binprm structure from the inode. 
909  * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
910  */
911 int prepare_binprm(struct linux_binprm *bprm)
912 {
913         int mode;
914         struct inode * inode = bprm->file->f_path.dentry->d_inode;
915         int retval;
916
917         mode = inode->i_mode;
918         if (bprm->file->f_op == NULL)
919                 return -EACCES;
920
921         bprm->e_uid = current->euid;
922         bprm->e_gid = current->egid;
923
924         if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
925                 /* Set-uid? */
926                 if (mode & S_ISUID) {
927                         current->personality &= ~PER_CLEAR_ON_SETID;
928                         bprm->e_uid = inode->i_uid;
929                 }
930
931                 /* Set-gid? */
932                 /*
933                  * If setgid is set but no group execute bit then this
934                  * is a candidate for mandatory locking, not a setgid
935                  * executable.
936                  */
937                 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
938                         current->personality &= ~PER_CLEAR_ON_SETID;
939                         bprm->e_gid = inode->i_gid;
940                 }
941         }
942
943         /* fill in binprm security blob */
944         retval = security_bprm_set(bprm);
945         if (retval)
946                 return retval;
947
948         memset(bprm->buf,0,BINPRM_BUF_SIZE);
949         return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
950 }
951
952 EXPORT_SYMBOL(prepare_binprm);
953
954 static int unsafe_exec(struct task_struct *p)
955 {
956         int unsafe = 0;
957         if (p->ptrace & PT_PTRACED) {
958                 if (p->ptrace & PT_PTRACE_CAP)
959                         unsafe |= LSM_UNSAFE_PTRACE_CAP;
960                 else
961                         unsafe |= LSM_UNSAFE_PTRACE;
962         }
963         if (atomic_read(&p->fs->count) > 1 ||
964             atomic_read(&p->files->count) > 1 ||
965             atomic_read(&p->sighand->count) > 1)
966                 unsafe |= LSM_UNSAFE_SHARE;
967
968         return unsafe;
969 }
970
971 void compute_creds(struct linux_binprm *bprm)
972 {
973         int unsafe;
974
975         if (bprm->e_uid != current->uid)
976                 suid_keys(current);
977         exec_keys(current);
978
979         task_lock(current);
980         unsafe = unsafe_exec(current);
981         security_bprm_apply_creds(bprm, unsafe);
982         task_unlock(current);
983         security_bprm_post_apply_creds(bprm);
984 }
985
986 EXPORT_SYMBOL(compute_creds);
987
988 void remove_arg_zero(struct linux_binprm *bprm)
989 {
990         if (bprm->argc) {
991                 unsigned long offset;
992                 char * kaddr;
993                 struct page *page;
994
995                 offset = bprm->p % PAGE_SIZE;
996                 goto inside;
997
998                 while (bprm->p++, *(kaddr+offset++)) {
999                         if (offset != PAGE_SIZE)
1000                                 continue;
1001                         offset = 0;
1002                         kunmap_atomic(kaddr, KM_USER0);
1003 inside:
1004                         page = bprm->page[bprm->p/PAGE_SIZE];
1005                         kaddr = kmap_atomic(page, KM_USER0);
1006                 }
1007                 kunmap_atomic(kaddr, KM_USER0);
1008                 bprm->argc--;
1009         }
1010 }
1011
1012 EXPORT_SYMBOL(remove_arg_zero);
1013
1014 /*
1015  * cycle the list of binary formats handler, until one recognizes the image
1016  */
1017 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1018 {
1019         int try,retval;
1020         struct linux_binfmt *fmt;
1021 #ifdef __alpha__
1022         /* handle /sbin/loader.. */
1023         {
1024             struct exec * eh = (struct exec *) bprm->buf;
1025
1026             if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1027                 (eh->fh.f_flags & 0x3000) == 0x3000)
1028             {
1029                 struct file * file;
1030                 unsigned long loader;
1031
1032                 allow_write_access(bprm->file);
1033                 fput(bprm->file);
1034                 bprm->file = NULL;
1035
1036                 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1037
1038                 file = open_exec("/sbin/loader");
1039                 retval = PTR_ERR(file);
1040                 if (IS_ERR(file))
1041                         return retval;
1042
1043                 /* Remember if the application is TASO.  */
1044                 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1045
1046                 bprm->file = file;
1047                 bprm->loader = loader;
1048                 retval = prepare_binprm(bprm);
1049                 if (retval<0)
1050                         return retval;
1051                 /* should call search_binary_handler recursively here,
1052                    but it does not matter */
1053             }
1054         }
1055 #endif
1056         retval = security_bprm_check(bprm);
1057         if (retval)
1058                 return retval;
1059
1060         /* kernel module loader fixup */
1061         /* so we don't try to load run modprobe in kernel space. */
1062         set_fs(USER_DS);
1063
1064         retval = audit_bprm(bprm);
1065         if (retval)
1066                 return retval;
1067
1068         retval = -ENOENT;
1069         for (try=0; try<2; try++) {
1070                 read_lock(&binfmt_lock);
1071                 for (fmt = formats ; fmt ; fmt = fmt->next) {
1072                         int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1073                         if (!fn)
1074                                 continue;
1075                         if (!try_module_get(fmt->module))
1076                                 continue;
1077                         read_unlock(&binfmt_lock);
1078                         retval = fn(bprm, regs);
1079                         if (retval >= 0) {
1080                                 put_binfmt(fmt);
1081                                 allow_write_access(bprm->file);
1082                                 if (bprm->file)
1083                                         fput(bprm->file);
1084                                 bprm->file = NULL;
1085                                 current->did_exec = 1;
1086                                 proc_exec_connector(current);
1087                                 return retval;
1088                         }
1089                         read_lock(&binfmt_lock);
1090                         put_binfmt(fmt);
1091                         if (retval != -ENOEXEC || bprm->mm == NULL)
1092                                 break;
1093                         if (!bprm->file) {
1094                                 read_unlock(&binfmt_lock);
1095                                 return retval;
1096                         }
1097                 }
1098                 read_unlock(&binfmt_lock);
1099                 if (retval != -ENOEXEC || bprm->mm == NULL) {
1100                         break;
1101 #ifdef CONFIG_KMOD
1102                 }else{
1103 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1104                         if (printable(bprm->buf[0]) &&
1105                             printable(bprm->buf[1]) &&
1106                             printable(bprm->buf[2]) &&
1107                             printable(bprm->buf[3]))
1108                                 break; /* -ENOEXEC */
1109                         request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1110 #endif
1111                 }
1112         }
1113         return retval;
1114 }
1115
1116 EXPORT_SYMBOL(search_binary_handler);
1117
1118 /*
1119  * sys_execve() executes a new program.
1120  */
1121 int do_execve(char * filename,
1122         char __user *__user *argv,
1123         char __user *__user *envp,
1124         struct pt_regs * regs)
1125 {
1126         struct linux_binprm *bprm;
1127         struct file *file;
1128         int retval;
1129         int i;
1130
1131         retval = -ENOMEM;
1132         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1133         if (!bprm)
1134                 goto out_ret;
1135
1136         file = open_exec(filename);
1137         retval = PTR_ERR(file);
1138         if (IS_ERR(file))
1139                 goto out_kfree;
1140
1141         sched_exec();
1142
1143         bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1144
1145         bprm->file = file;
1146         bprm->filename = filename;
1147         bprm->interp = filename;
1148         bprm->mm = mm_alloc();
1149         retval = -ENOMEM;
1150         if (!bprm->mm)
1151                 goto out_file;
1152
1153         retval = init_new_context(current, bprm->mm);
1154         if (retval < 0)
1155                 goto out_mm;
1156
1157         bprm->argc = count(argv, bprm->p / sizeof(void *));
1158         if ((retval = bprm->argc) < 0)
1159                 goto out_mm;
1160
1161         bprm->envc = count(envp, bprm->p / sizeof(void *));
1162         if ((retval = bprm->envc) < 0)
1163                 goto out_mm;
1164
1165         retval = security_bprm_alloc(bprm);
1166         if (retval)
1167                 goto out;
1168
1169         retval = prepare_binprm(bprm);
1170         if (retval < 0)
1171                 goto out;
1172
1173         retval = copy_strings_kernel(1, &bprm->filename, bprm);
1174         if (retval < 0)
1175                 goto out;
1176
1177         bprm->exec = bprm->p;
1178         retval = copy_strings(bprm->envc, envp, bprm);
1179         if (retval < 0)
1180                 goto out;
1181
1182         retval = copy_strings(bprm->argc, argv, bprm);
1183         if (retval < 0)
1184                 goto out;
1185
1186         retval = search_binary_handler(bprm,regs);
1187         if (retval >= 0) {
1188                 free_arg_pages(bprm);
1189
1190                 /* execve success */
1191                 security_bprm_free(bprm);
1192                 acct_update_integrals(current);
1193                 kfree(bprm);
1194                 return retval;
1195         }
1196
1197 out:
1198         /* Something went wrong, return the inode and free the argument pages*/
1199         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1200                 struct page * page = bprm->page[i];
1201                 if (page)
1202                         __free_page(page);
1203         }
1204
1205         if (bprm->security)
1206                 security_bprm_free(bprm);
1207
1208 out_mm:
1209         if (bprm->mm)
1210                 mmdrop(bprm->mm);
1211
1212 out_file:
1213         if (bprm->file) {
1214                 allow_write_access(bprm->file);
1215                 fput(bprm->file);
1216         }
1217
1218 out_kfree:
1219         kfree(bprm);
1220
1221 out_ret:
1222         return retval;
1223 }
1224
1225 int set_binfmt(struct linux_binfmt *new)
1226 {
1227         struct linux_binfmt *old = current->binfmt;
1228
1229         if (new) {
1230                 if (!try_module_get(new->module))
1231                         return -1;
1232         }
1233         current->binfmt = new;
1234         if (old)
1235                 module_put(old->module);
1236         return 0;
1237 }
1238
1239 EXPORT_SYMBOL(set_binfmt);
1240
1241 #define CORENAME_MAX_SIZE 64
1242
1243 /* format_corename will inspect the pattern parameter, and output a
1244  * name into corename, which must have space for at least
1245  * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1246  */
1247 static void format_corename(char *corename, const char *pattern, long signr)
1248 {
1249         const char *pat_ptr = pattern;
1250         char *out_ptr = corename;
1251         char *const out_end = corename + CORENAME_MAX_SIZE;
1252         int rc;
1253         int pid_in_pattern = 0;
1254
1255         /* Repeat as long as we have more pattern to process and more output
1256            space */
1257         while (*pat_ptr) {
1258                 if (*pat_ptr != '%') {
1259                         if (out_ptr == out_end)
1260                                 goto out;
1261                         *out_ptr++ = *pat_ptr++;
1262                 } else {
1263                         switch (*++pat_ptr) {
1264                         case 0:
1265                                 goto out;
1266                         /* Double percent, output one percent */
1267                         case '%':
1268                                 if (out_ptr == out_end)
1269                                         goto out;
1270                                 *out_ptr++ = '%';
1271                                 break;
1272                         /* pid */
1273                         case 'p':
1274                                 pid_in_pattern = 1;
1275                                 rc = snprintf(out_ptr, out_end - out_ptr,
1276                                               "%d", current->tgid);
1277                                 if (rc > out_end - out_ptr)
1278                                         goto out;
1279                                 out_ptr += rc;
1280                                 break;
1281                         /* uid */
1282                         case 'u':
1283                                 rc = snprintf(out_ptr, out_end - out_ptr,
1284                                               "%d", current->uid);
1285                                 if (rc > out_end - out_ptr)
1286                                         goto out;
1287                                 out_ptr += rc;
1288                                 break;
1289                         /* gid */
1290                         case 'g':
1291                                 rc = snprintf(out_ptr, out_end - out_ptr,
1292                                               "%d", current->gid);
1293                                 if (rc > out_end - out_ptr)
1294                                         goto out;
1295                                 out_ptr += rc;
1296                                 break;
1297                         /* signal that caused the coredump */
1298                         case 's':
1299                                 rc = snprintf(out_ptr, out_end - out_ptr,
1300                                               "%ld", signr);
1301                                 if (rc > out_end - out_ptr)
1302                                         goto out;
1303                                 out_ptr += rc;
1304                                 break;
1305                         /* UNIX time of coredump */
1306                         case 't': {
1307                                 struct timeval tv;
1308                                 do_gettimeofday(&tv);
1309                                 rc = snprintf(out_ptr, out_end - out_ptr,
1310                                               "%lu", tv.tv_sec);
1311                                 if (rc > out_end - out_ptr)
1312                                         goto out;
1313                                 out_ptr += rc;
1314                                 break;
1315                         }
1316                         /* hostname */
1317                         case 'h':
1318                                 down_read(&uts_sem);
1319                                 rc = snprintf(out_ptr, out_end - out_ptr,
1320                                               "%s", utsname()->nodename);
1321                                 up_read(&uts_sem);
1322                                 if (rc > out_end - out_ptr)
1323                                         goto out;
1324                                 out_ptr += rc;
1325                                 break;
1326                         /* executable */
1327                         case 'e':
1328                                 rc = snprintf(out_ptr, out_end - out_ptr,
1329                                               "%s", current->comm);
1330                                 if (rc > out_end - out_ptr)
1331                                         goto out;
1332                                 out_ptr += rc;
1333                                 break;
1334                         default:
1335                                 break;
1336                         }
1337                         ++pat_ptr;
1338                 }
1339         }
1340         /* Backward compatibility with core_uses_pid:
1341          *
1342          * If core_pattern does not include a %p (as is the default)
1343          * and core_uses_pid is set, then .%pid will be appended to
1344          * the filename */
1345         if (!pid_in_pattern
1346             && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1347                 rc = snprintf(out_ptr, out_end - out_ptr,
1348                               ".%d", current->tgid);
1349                 if (rc > out_end - out_ptr)
1350                         goto out;
1351                 out_ptr += rc;
1352         }
1353       out:
1354         *out_ptr = 0;
1355 }
1356
1357 static void zap_process(struct task_struct *start)
1358 {
1359         struct task_struct *t;
1360
1361         start->signal->flags = SIGNAL_GROUP_EXIT;
1362         start->signal->group_stop_count = 0;
1363
1364         t = start;
1365         do {
1366                 if (t != current && t->mm) {
1367                         t->mm->core_waiters++;
1368                         sigaddset(&t->pending.signal, SIGKILL);
1369                         signal_wake_up(t, 1);
1370                 }
1371         } while ((t = next_thread(t)) != start);
1372 }
1373
1374 static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
1375                                 int exit_code)
1376 {
1377         struct task_struct *g, *p;
1378         unsigned long flags;
1379         int err = -EAGAIN;
1380
1381         spin_lock_irq(&tsk->sighand->siglock);
1382         if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
1383                 tsk->signal->group_exit_code = exit_code;
1384                 zap_process(tsk);
1385                 err = 0;
1386         }
1387         spin_unlock_irq(&tsk->sighand->siglock);
1388         if (err)
1389                 return err;
1390
1391         if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
1392                 goto done;
1393
1394         rcu_read_lock();
1395         for_each_process(g) {
1396                 if (g == tsk->group_leader)
1397                         continue;
1398
1399                 p = g;
1400                 do {
1401                         if (p->mm) {
1402                                 if (p->mm == mm) {
1403                                         /*
1404                                          * p->sighand can't disappear, but
1405                                          * may be changed by de_thread()
1406                                          */
1407                                         lock_task_sighand(p, &flags);
1408                                         zap_process(p);
1409                                         unlock_task_sighand(p, &flags);
1410                                 }
1411                                 break;
1412                         }
1413                 } while ((p = next_thread(p)) != g);
1414         }
1415         rcu_read_unlock();
1416 done:
1417         return mm->core_waiters;
1418 }
1419
1420 static int coredump_wait(int exit_code)
1421 {
1422         struct task_struct *tsk = current;
1423         struct mm_struct *mm = tsk->mm;
1424         struct completion startup_done;
1425         struct completion *vfork_done;
1426         int core_waiters;
1427
1428         init_completion(&mm->core_done);
1429         init_completion(&startup_done);
1430         mm->core_startup_done = &startup_done;
1431
1432         core_waiters = zap_threads(tsk, mm, exit_code);
1433         up_write(&mm->mmap_sem);
1434
1435         if (unlikely(core_waiters < 0))
1436                 goto fail;
1437
1438         /*
1439          * Make sure nobody is waiting for us to release the VM,
1440          * otherwise we can deadlock when we wait on each other
1441          */
1442         vfork_done = tsk->vfork_done;
1443         if (vfork_done) {
1444                 tsk->vfork_done = NULL;
1445                 complete(vfork_done);
1446         }
1447
1448         if (core_waiters)
1449                 wait_for_completion(&startup_done);
1450 fail:
1451         BUG_ON(mm->core_waiters);
1452         return core_waiters;
1453 }
1454
1455 int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1456 {
1457         char corename[CORENAME_MAX_SIZE + 1];
1458         struct mm_struct *mm = current->mm;
1459         struct linux_binfmt * binfmt;
1460         struct inode * inode;
1461         struct file * file;
1462         int retval = 0;
1463         int fsuid = current->fsuid;
1464         int flag = 0;
1465         int ispipe = 0;
1466
1467         binfmt = current->binfmt;
1468         if (!binfmt || !binfmt->core_dump)
1469                 goto fail;
1470         down_write(&mm->mmap_sem);
1471         if (!mm->dumpable) {
1472                 up_write(&mm->mmap_sem);
1473                 goto fail;
1474         }
1475
1476         /*
1477          *      We cannot trust fsuid as being the "true" uid of the
1478          *      process nor do we know its entire history. We only know it
1479          *      was tainted so we dump it as root in mode 2.
1480          */
1481         if (mm->dumpable == 2) {        /* Setuid core dump mode */
1482                 flag = O_EXCL;          /* Stop rewrite attacks */
1483                 current->fsuid = 0;     /* Dump root private */
1484         }
1485         mm->dumpable = 0;
1486
1487         retval = coredump_wait(exit_code);
1488         if (retval < 0)
1489                 goto fail;
1490
1491         /*
1492          * Clear any false indication of pending signals that might
1493          * be seen by the filesystem code called to write the core file.
1494          */
1495         clear_thread_flag(TIF_SIGPENDING);
1496
1497         if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1498                 goto fail_unlock;
1499
1500         /*
1501          * lock_kernel() because format_corename() is controlled by sysctl, which
1502          * uses lock_kernel()
1503          */
1504         lock_kernel();
1505         format_corename(corename, core_pattern, signr);
1506         unlock_kernel();
1507         if (corename[0] == '|') {
1508                 /* SIGPIPE can happen, but it's just never processed */
1509                 if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) {
1510                         printk(KERN_INFO "Core dump to %s pipe failed\n",
1511                                corename);
1512                         goto fail_unlock;
1513                 }
1514                 ispipe = 1;
1515         } else
1516                 file = filp_open(corename,
1517                                  O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
1518                                  0600);
1519         if (IS_ERR(file))
1520                 goto fail_unlock;
1521         inode = file->f_path.dentry->d_inode;
1522         if (inode->i_nlink > 1)
1523                 goto close_fail;        /* multiple links - don't dump */
1524         if (!ispipe && d_unhashed(file->f_path.dentry))
1525                 goto close_fail;
1526
1527         /* AK: actually i see no reason to not allow this for named pipes etc.,
1528            but keep the previous behaviour for now. */
1529         if (!ispipe && !S_ISREG(inode->i_mode))
1530                 goto close_fail;
1531         if (!file->f_op)
1532                 goto close_fail;
1533         if (!file->f_op->write)
1534                 goto close_fail;
1535         if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
1536                 goto close_fail;
1537
1538         retval = binfmt->core_dump(signr, regs, file);
1539
1540         if (retval)
1541                 current->signal->group_exit_code |= 0x80;
1542 close_fail:
1543         filp_close(file, NULL);
1544 fail_unlock:
1545         current->fsuid = fsuid;
1546         complete_all(&mm->core_done);
1547 fail:
1548         return retval;
1549 }