[PATCH] VFS: Permit filesystem to perform statfs with a known root dentry
[linux-2.6.git] / fs / exec.c
1 /*
2  *  linux/fs/exec.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6
7 /*
8  * #!-checking implemented by tytso.
9  */
10 /*
11  * Demand-loading implemented 01.12.91 - no need to read anything but
12  * the header into memory. The inode of the executable is put into
13  * "current->executable", and page faults do the actual loading. Clean.
14  *
15  * Once more I can proudly say that linux stood up to being changed: it
16  * was less than 2 hours work to get demand-loading completely implemented.
17  *
18  * Demand loading changed July 1993 by Eric Youngdale.   Use mmap instead,
19  * current->executable is only used by the procfs.  This allows a dispatch
20  * table to check for several different types  of binary formats.  We keep
21  * trying until we recognize the file or we run out of supported binary
22  * formats. 
23  */
24
25 #include <linux/config.h>
26 #include <linux/slab.h>
27 #include <linux/file.h>
28 #include <linux/mman.h>
29 #include <linux/a.out.h>
30 #include <linux/stat.h>
31 #include <linux/fcntl.h>
32 #include <linux/smp_lock.h>
33 #include <linux/init.h>
34 #include <linux/pagemap.h>
35 #include <linux/highmem.h>
36 #include <linux/spinlock.h>
37 #include <linux/key.h>
38 #include <linux/personality.h>
39 #include <linux/binfmts.h>
40 #include <linux/swap.h>
41 #include <linux/utsname.h>
42 #include <linux/module.h>
43 #include <linux/namei.h>
44 #include <linux/proc_fs.h>
45 #include <linux/ptrace.h>
46 #include <linux/mount.h>
47 #include <linux/security.h>
48 #include <linux/syscalls.h>
49 #include <linux/rmap.h>
50 #include <linux/acct.h>
51 #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[65] = "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_alloc(vm_area_cachep, SLAB_KERNEL);
409         if (!mpnt)
410                 return -ENOMEM;
411
412         memset(mpnt, 0, sizeof(*mpnt));
413
414         down_write(&mm->mmap_sem);
415         {
416                 mpnt->vm_mm = mm;
417 #ifdef CONFIG_STACK_GROWSUP
418                 mpnt->vm_start = stack_base;
419                 mpnt->vm_end = stack_base + arg_size;
420 #else
421                 mpnt->vm_end = stack_top;
422                 mpnt->vm_start = mpnt->vm_end - arg_size;
423 #endif
424                 /* Adjust stack execute permissions; explicitly enable
425                  * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
426                  * and leave alone (arch default) otherwise. */
427                 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
428                         mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
429                 else if (executable_stack == EXSTACK_DISABLE_X)
430                         mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
431                 else
432                         mpnt->vm_flags = VM_STACK_FLAGS;
433                 mpnt->vm_flags |= mm->def_flags;
434                 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
435                 if ((ret = insert_vm_struct(mm, mpnt))) {
436                         up_write(&mm->mmap_sem);
437                         kmem_cache_free(vm_area_cachep, mpnt);
438                         return ret;
439                 }
440                 mm->stack_vm = mm->total_vm = vma_pages(mpnt);
441         }
442
443         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
444                 struct page *page = bprm->page[i];
445                 if (page) {
446                         bprm->page[i] = NULL;
447                         install_arg_page(mpnt, page, stack_base);
448                 }
449                 stack_base += PAGE_SIZE;
450         }
451         up_write(&mm->mmap_sem);
452         
453         return 0;
454 }
455
456 EXPORT_SYMBOL(setup_arg_pages);
457
458 #define free_arg_pages(bprm) do { } while (0)
459
460 #else
461
462 static inline void free_arg_pages(struct linux_binprm *bprm)
463 {
464         int i;
465
466         for (i = 0; i < MAX_ARG_PAGES; i++) {
467                 if (bprm->page[i])
468                         __free_page(bprm->page[i]);
469                 bprm->page[i] = NULL;
470         }
471 }
472
473 #endif /* CONFIG_MMU */
474
475 struct file *open_exec(const char *name)
476 {
477         struct nameidata nd;
478         int err;
479         struct file *file;
480
481         err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
482         file = ERR_PTR(err);
483
484         if (!err) {
485                 struct inode *inode = nd.dentry->d_inode;
486                 file = ERR_PTR(-EACCES);
487                 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
488                     S_ISREG(inode->i_mode)) {
489                         int err = vfs_permission(&nd, MAY_EXEC);
490                         if (!err && !(inode->i_mode & 0111))
491                                 err = -EACCES;
492                         file = ERR_PTR(err);
493                         if (!err) {
494                                 file = nameidata_to_filp(&nd, O_RDONLY);
495                                 if (!IS_ERR(file)) {
496                                         err = deny_write_access(file);
497                                         if (err) {
498                                                 fput(file);
499                                                 file = ERR_PTR(err);
500                                         }
501                                 }
502 out:
503                                 return file;
504                         }
505                 }
506                 release_open_intent(&nd);
507                 path_release(&nd);
508         }
509         goto out;
510 }
511
512 EXPORT_SYMBOL(open_exec);
513
514 int kernel_read(struct file *file, unsigned long offset,
515         char *addr, unsigned long count)
516 {
517         mm_segment_t old_fs;
518         loff_t pos = offset;
519         int result;
520
521         old_fs = get_fs();
522         set_fs(get_ds());
523         /* The cast to a user pointer is valid due to the set_fs() */
524         result = vfs_read(file, (void __user *)addr, count, &pos);
525         set_fs(old_fs);
526         return result;
527 }
528
529 EXPORT_SYMBOL(kernel_read);
530
531 static int exec_mmap(struct mm_struct *mm)
532 {
533         struct task_struct *tsk;
534         struct mm_struct * old_mm, *active_mm;
535
536         /* Notify parent that we're no longer interested in the old VM */
537         tsk = current;
538         old_mm = current->mm;
539         mm_release(tsk, old_mm);
540
541         if (old_mm) {
542                 /*
543                  * Make sure that if there is a core dump in progress
544                  * for the old mm, we get out and die instead of going
545                  * through with the exec.  We must hold mmap_sem around
546                  * checking core_waiters and changing tsk->mm.  The
547                  * core-inducing thread will increment core_waiters for
548                  * each thread whose ->mm == old_mm.
549                  */
550                 down_read(&old_mm->mmap_sem);
551                 if (unlikely(old_mm->core_waiters)) {
552                         up_read(&old_mm->mmap_sem);
553                         return -EINTR;
554                 }
555         }
556         task_lock(tsk);
557         active_mm = tsk->active_mm;
558         tsk->mm = mm;
559         tsk->active_mm = mm;
560         activate_mm(active_mm, mm);
561         task_unlock(tsk);
562         arch_pick_mmap_layout(mm);
563         if (old_mm) {
564                 up_read(&old_mm->mmap_sem);
565                 BUG_ON(active_mm != old_mm);
566                 mmput(old_mm);
567                 return 0;
568         }
569         mmdrop(active_mm);
570         return 0;
571 }
572
573 /*
574  * This function makes sure the current process has its own signal table,
575  * so that flush_signal_handlers can later reset the handlers without
576  * disturbing other processes.  (Other processes might share the signal
577  * table via the CLONE_SIGHAND option to clone().)
578  */
579 static int de_thread(struct task_struct *tsk)
580 {
581         struct signal_struct *sig = tsk->signal;
582         struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
583         spinlock_t *lock = &oldsighand->siglock;
584         struct task_struct *leader = NULL;
585         int count;
586
587         /*
588          * If we don't share sighandlers, then we aren't sharing anything
589          * and we can just re-use it all.
590          */
591         if (atomic_read(&oldsighand->count) <= 1) {
592                 BUG_ON(atomic_read(&sig->count) != 1);
593                 exit_itimers(sig);
594                 return 0;
595         }
596
597         newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
598         if (!newsighand)
599                 return -ENOMEM;
600
601         if (thread_group_empty(current))
602                 goto no_thread_group;
603
604         /*
605          * Kill all other threads in the thread group.
606          * We must hold tasklist_lock to call zap_other_threads.
607          */
608         read_lock(&tasklist_lock);
609         spin_lock_irq(lock);
610         if (sig->flags & SIGNAL_GROUP_EXIT) {
611                 /*
612                  * Another group action in progress, just
613                  * return so that the signal is processed.
614                  */
615                 spin_unlock_irq(lock);
616                 read_unlock(&tasklist_lock);
617                 kmem_cache_free(sighand_cachep, newsighand);
618                 return -EAGAIN;
619         }
620
621         /*
622          * child_reaper ignores SIGKILL, change it now.
623          * Reparenting needs write_lock on tasklist_lock,
624          * so it is safe to do it under read_lock.
625          */
626         if (unlikely(current->group_leader == child_reaper))
627                 child_reaper = current;
628
629         zap_other_threads(current);
630         read_unlock(&tasklist_lock);
631
632         /*
633          * Account for the thread group leader hanging around:
634          */
635         count = 1;
636         if (!thread_group_leader(current)) {
637                 count = 2;
638                 /*
639                  * The SIGALRM timer survives the exec, but needs to point
640                  * at us as the new group leader now.  We have a race with
641                  * a timer firing now getting the old leader, so we need to
642                  * synchronize with any firing (by calling del_timer_sync)
643                  * before we can safely let the old group leader die.
644                  */
645                 sig->tsk = current;
646                 spin_unlock_irq(lock);
647                 if (hrtimer_cancel(&sig->real_timer))
648                         hrtimer_restart(&sig->real_timer);
649                 spin_lock_irq(lock);
650         }
651         while (atomic_read(&sig->count) > count) {
652                 sig->group_exit_task = current;
653                 sig->notify_count = count;
654                 __set_current_state(TASK_UNINTERRUPTIBLE);
655                 spin_unlock_irq(lock);
656                 schedule();
657                 spin_lock_irq(lock);
658         }
659         sig->group_exit_task = NULL;
660         sig->notify_count = 0;
661         spin_unlock_irq(lock);
662
663         /*
664          * At this point all other threads have exited, all we have to
665          * do is to wait for the thread group leader to become inactive,
666          * and to assume its PID:
667          */
668         if (!thread_group_leader(current)) {
669                 struct dentry *proc_dentry1, *proc_dentry2;
670
671                 /*
672                  * Wait for the thread group leader to be a zombie.
673                  * It should already be zombie at this point, most
674                  * of the time.
675                  */
676                 leader = current->group_leader;
677                 while (leader->exit_state != EXIT_ZOMBIE)
678                         yield();
679
680                 /*
681                  * The only record we have of the real-time age of a
682                  * process, regardless of execs it's done, is start_time.
683                  * All the past CPU time is accumulated in signal_struct
684                  * from sister threads now dead.  But in this non-leader
685                  * exec, nothing survives from the original leader thread,
686                  * whose birth marks the true age of this process now.
687                  * When we take on its identity by switching to its PID, we
688                  * also take its birthdate (always earlier than our own).
689                  */
690                 current->start_time = leader->start_time;
691
692                 spin_lock(&leader->proc_lock);
693                 spin_lock(&current->proc_lock);
694                 proc_dentry1 = proc_pid_unhash(current);
695                 proc_dentry2 = proc_pid_unhash(leader);
696                 write_lock_irq(&tasklist_lock);
697
698                 BUG_ON(leader->tgid != current->tgid);
699                 BUG_ON(current->pid == current->tgid);
700                 /*
701                  * An exec() starts a new thread group with the
702                  * TGID of the previous thread group. Rehash the
703                  * two threads with a switched PID, and release
704                  * the former thread group leader:
705                  */
706
707                 /* Become a process group leader with the old leader's pid.
708                  * Note: The old leader also uses thispid until release_task
709                  *       is called.  Odd but simple and correct.
710                  */
711                 detach_pid(current, PIDTYPE_PID);
712                 current->pid = leader->pid;
713                 attach_pid(current, PIDTYPE_PID,  current->pid);
714                 attach_pid(current, PIDTYPE_PGID, current->signal->pgrp);
715                 attach_pid(current, PIDTYPE_SID,  current->signal->session);
716                 list_add_tail_rcu(&current->tasks, &init_task.tasks);
717
718                 current->group_leader = current;
719                 leader->group_leader = current;
720
721                 /* Reduce leader to a thread */
722                 detach_pid(leader, PIDTYPE_PGID);
723                 detach_pid(leader, PIDTYPE_SID);
724                 list_del_init(&leader->tasks);
725
726                 current->exit_signal = SIGCHLD;
727
728                 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
729                 leader->exit_state = EXIT_DEAD;
730
731                 write_unlock_irq(&tasklist_lock);
732                 spin_unlock(&leader->proc_lock);
733                 spin_unlock(&current->proc_lock);
734                 proc_pid_flush(proc_dentry1);
735                 proc_pid_flush(proc_dentry2);
736         }
737
738         /*
739          * There may be one thread left which is just exiting,
740          * but it's safe to stop telling the group to kill themselves.
741          */
742         sig->flags = 0;
743
744 no_thread_group:
745         exit_itimers(sig);
746         if (leader)
747                 release_task(leader);
748
749         BUG_ON(atomic_read(&sig->count) != 1);
750
751         if (atomic_read(&oldsighand->count) == 1) {
752                 /*
753                  * Now that we nuked the rest of the thread group,
754                  * it turns out we are not sharing sighand any more either.
755                  * So we can just keep it.
756                  */
757                 kmem_cache_free(sighand_cachep, newsighand);
758         } else {
759                 /*
760                  * Move our state over to newsighand and switch it in.
761                  */
762                 atomic_set(&newsighand->count, 1);
763                 memcpy(newsighand->action, oldsighand->action,
764                        sizeof(newsighand->action));
765
766                 write_lock_irq(&tasklist_lock);
767                 spin_lock(&oldsighand->siglock);
768                 spin_lock(&newsighand->siglock);
769
770                 rcu_assign_pointer(current->sighand, newsighand);
771                 recalc_sigpending();
772
773                 spin_unlock(&newsighand->siglock);
774                 spin_unlock(&oldsighand->siglock);
775                 write_unlock_irq(&tasklist_lock);
776
777                 if (atomic_dec_and_test(&oldsighand->count))
778                         kmem_cache_free(sighand_cachep, oldsighand);
779         }
780
781         BUG_ON(!thread_group_leader(current));
782         return 0;
783 }
784         
785 /*
786  * These functions flushes out all traces of the currently running executable
787  * so that a new one can be started
788  */
789
790 static void flush_old_files(struct files_struct * files)
791 {
792         long j = -1;
793         struct fdtable *fdt;
794
795         spin_lock(&files->file_lock);
796         for (;;) {
797                 unsigned long set, i;
798
799                 j++;
800                 i = j * __NFDBITS;
801                 fdt = files_fdtable(files);
802                 if (i >= fdt->max_fds || i >= fdt->max_fdset)
803                         break;
804                 set = fdt->close_on_exec->fds_bits[j];
805                 if (!set)
806                         continue;
807                 fdt->close_on_exec->fds_bits[j] = 0;
808                 spin_unlock(&files->file_lock);
809                 for ( ; set ; i++,set >>= 1) {
810                         if (set & 1) {
811                                 sys_close(i);
812                         }
813                 }
814                 spin_lock(&files->file_lock);
815
816         }
817         spin_unlock(&files->file_lock);
818 }
819
820 void get_task_comm(char *buf, struct task_struct *tsk)
821 {
822         /* buf must be at least sizeof(tsk->comm) in size */
823         task_lock(tsk);
824         strncpy(buf, tsk->comm, sizeof(tsk->comm));
825         task_unlock(tsk);
826 }
827
828 void set_task_comm(struct task_struct *tsk, char *buf)
829 {
830         task_lock(tsk);
831         strlcpy(tsk->comm, buf, sizeof(tsk->comm));
832         task_unlock(tsk);
833 }
834
835 int flush_old_exec(struct linux_binprm * bprm)
836 {
837         char * name;
838         int i, ch, retval;
839         struct files_struct *files;
840         char tcomm[sizeof(current->comm)];
841
842         /*
843          * Make sure we have a private signal table and that
844          * we are unassociated from the previous thread group.
845          */
846         retval = de_thread(current);
847         if (retval)
848                 goto out;
849
850         /*
851          * Make sure we have private file handles. Ask the
852          * fork helper to do the work for us and the exit
853          * helper to do the cleanup of the old one.
854          */
855         files = current->files;         /* refcounted so safe to hold */
856         retval = unshare_files();
857         if (retval)
858                 goto out;
859         /*
860          * Release all of the old mmap stuff
861          */
862         retval = exec_mmap(bprm->mm);
863         if (retval)
864                 goto mmap_failed;
865
866         bprm->mm = NULL;                /* We're using it now */
867
868         /* This is the point of no return */
869         put_files_struct(files);
870
871         current->sas_ss_sp = current->sas_ss_size = 0;
872
873         if (current->euid == current->uid && current->egid == current->gid)
874                 current->mm->dumpable = 1;
875         else
876                 current->mm->dumpable = suid_dumpable;
877
878         name = bprm->filename;
879
880         /* Copies the binary name from after last slash */
881         for (i=0; (ch = *(name++)) != '\0';) {
882                 if (ch == '/')
883                         i = 0; /* overwrite what we wrote */
884                 else
885                         if (i < (sizeof(tcomm) - 1))
886                                 tcomm[i++] = ch;
887         }
888         tcomm[i] = '\0';
889         set_task_comm(current, tcomm);
890
891         current->flags &= ~PF_RANDOMIZE;
892         flush_thread();
893
894         /* Set the new mm task size. We have to do that late because it may
895          * depend on TIF_32BIT which is only updated in flush_thread() on
896          * some architectures like powerpc
897          */
898         current->mm->task_size = TASK_SIZE;
899
900         if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || 
901             file_permission(bprm->file, MAY_READ) ||
902             (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
903                 suid_keys(current);
904                 current->mm->dumpable = suid_dumpable;
905         }
906
907         /* An exec changes our domain. We are no longer part of the thread
908            group */
909
910         current->self_exec_id++;
911                         
912         flush_signal_handlers(current, 0);
913         flush_old_files(current->files);
914
915         return 0;
916
917 mmap_failed:
918         put_files_struct(current->files);
919         current->files = files;
920 out:
921         return retval;
922 }
923
924 EXPORT_SYMBOL(flush_old_exec);
925
926 /* 
927  * Fill the binprm structure from the inode. 
928  * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
929  */
930 int prepare_binprm(struct linux_binprm *bprm)
931 {
932         int mode;
933         struct inode * inode = bprm->file->f_dentry->d_inode;
934         int retval;
935
936         mode = inode->i_mode;
937         /*
938          * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
939          * generic_permission lets a non-executable through
940          */
941         if (!(mode & 0111))     /* with at least _one_ execute bit set */
942                 return -EACCES;
943         if (bprm->file->f_op == NULL)
944                 return -EACCES;
945
946         bprm->e_uid = current->euid;
947         bprm->e_gid = current->egid;
948
949         if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) {
950                 /* Set-uid? */
951                 if (mode & S_ISUID) {
952                         current->personality &= ~PER_CLEAR_ON_SETID;
953                         bprm->e_uid = inode->i_uid;
954                 }
955
956                 /* Set-gid? */
957                 /*
958                  * If setgid is set but no group execute bit then this
959                  * is a candidate for mandatory locking, not a setgid
960                  * executable.
961                  */
962                 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
963                         current->personality &= ~PER_CLEAR_ON_SETID;
964                         bprm->e_gid = inode->i_gid;
965                 }
966         }
967
968         /* fill in binprm security blob */
969         retval = security_bprm_set(bprm);
970         if (retval)
971                 return retval;
972
973         memset(bprm->buf,0,BINPRM_BUF_SIZE);
974         return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
975 }
976
977 EXPORT_SYMBOL(prepare_binprm);
978
979 static int unsafe_exec(struct task_struct *p)
980 {
981         int unsafe = 0;
982         if (p->ptrace & PT_PTRACED) {
983                 if (p->ptrace & PT_PTRACE_CAP)
984                         unsafe |= LSM_UNSAFE_PTRACE_CAP;
985                 else
986                         unsafe |= LSM_UNSAFE_PTRACE;
987         }
988         if (atomic_read(&p->fs->count) > 1 ||
989             atomic_read(&p->files->count) > 1 ||
990             atomic_read(&p->sighand->count) > 1)
991                 unsafe |= LSM_UNSAFE_SHARE;
992
993         return unsafe;
994 }
995
996 void compute_creds(struct linux_binprm *bprm)
997 {
998         int unsafe;
999
1000         if (bprm->e_uid != current->uid)
1001                 suid_keys(current);
1002         exec_keys(current);
1003
1004         task_lock(current);
1005         unsafe = unsafe_exec(current);
1006         security_bprm_apply_creds(bprm, unsafe);
1007         task_unlock(current);
1008         security_bprm_post_apply_creds(bprm);
1009 }
1010
1011 EXPORT_SYMBOL(compute_creds);
1012
1013 void remove_arg_zero(struct linux_binprm *bprm)
1014 {
1015         if (bprm->argc) {
1016                 unsigned long offset;
1017                 char * kaddr;
1018                 struct page *page;
1019
1020                 offset = bprm->p % PAGE_SIZE;
1021                 goto inside;
1022
1023                 while (bprm->p++, *(kaddr+offset++)) {
1024                         if (offset != PAGE_SIZE)
1025                                 continue;
1026                         offset = 0;
1027                         kunmap_atomic(kaddr, KM_USER0);
1028 inside:
1029                         page = bprm->page[bprm->p/PAGE_SIZE];
1030                         kaddr = kmap_atomic(page, KM_USER0);
1031                 }
1032                 kunmap_atomic(kaddr, KM_USER0);
1033                 bprm->argc--;
1034         }
1035 }
1036
1037 EXPORT_SYMBOL(remove_arg_zero);
1038
1039 /*
1040  * cycle the list of binary formats handler, until one recognizes the image
1041  */
1042 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1043 {
1044         int try,retval;
1045         struct linux_binfmt *fmt;
1046 #ifdef __alpha__
1047         /* handle /sbin/loader.. */
1048         {
1049             struct exec * eh = (struct exec *) bprm->buf;
1050
1051             if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1052                 (eh->fh.f_flags & 0x3000) == 0x3000)
1053             {
1054                 struct file * file;
1055                 unsigned long loader;
1056
1057                 allow_write_access(bprm->file);
1058                 fput(bprm->file);
1059                 bprm->file = NULL;
1060
1061                 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1062
1063                 file = open_exec("/sbin/loader");
1064                 retval = PTR_ERR(file);
1065                 if (IS_ERR(file))
1066                         return retval;
1067
1068                 /* Remember if the application is TASO.  */
1069                 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1070
1071                 bprm->file = file;
1072                 bprm->loader = loader;
1073                 retval = prepare_binprm(bprm);
1074                 if (retval<0)
1075                         return retval;
1076                 /* should call search_binary_handler recursively here,
1077                    but it does not matter */
1078             }
1079         }
1080 #endif
1081         retval = security_bprm_check(bprm);
1082         if (retval)
1083                 return retval;
1084
1085         /* kernel module loader fixup */
1086         /* so we don't try to load run modprobe in kernel space. */
1087         set_fs(USER_DS);
1088
1089         retval = audit_bprm(bprm);
1090         if (retval)
1091                 return retval;
1092
1093         retval = -ENOENT;
1094         for (try=0; try<2; try++) {
1095                 read_lock(&binfmt_lock);
1096                 for (fmt = formats ; fmt ; fmt = fmt->next) {
1097                         int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1098                         if (!fn)
1099                                 continue;
1100                         if (!try_module_get(fmt->module))
1101                                 continue;
1102                         read_unlock(&binfmt_lock);
1103                         retval = fn(bprm, regs);
1104                         if (retval >= 0) {
1105                                 put_binfmt(fmt);
1106                                 allow_write_access(bprm->file);
1107                                 if (bprm->file)
1108                                         fput(bprm->file);
1109                                 bprm->file = NULL;
1110                                 current->did_exec = 1;
1111                                 proc_exec_connector(current);
1112                                 return retval;
1113                         }
1114                         read_lock(&binfmt_lock);
1115                         put_binfmt(fmt);
1116                         if (retval != -ENOEXEC || bprm->mm == NULL)
1117                                 break;
1118                         if (!bprm->file) {
1119                                 read_unlock(&binfmt_lock);
1120                                 return retval;
1121                         }
1122                 }
1123                 read_unlock(&binfmt_lock);
1124                 if (retval != -ENOEXEC || bprm->mm == NULL) {
1125                         break;
1126 #ifdef CONFIG_KMOD
1127                 }else{
1128 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1129                         if (printable(bprm->buf[0]) &&
1130                             printable(bprm->buf[1]) &&
1131                             printable(bprm->buf[2]) &&
1132                             printable(bprm->buf[3]))
1133                                 break; /* -ENOEXEC */
1134                         request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1135 #endif
1136                 }
1137         }
1138         return retval;
1139 }
1140
1141 EXPORT_SYMBOL(search_binary_handler);
1142
1143 /*
1144  * sys_execve() executes a new program.
1145  */
1146 int do_execve(char * filename,
1147         char __user *__user *argv,
1148         char __user *__user *envp,
1149         struct pt_regs * regs)
1150 {
1151         struct linux_binprm *bprm;
1152         struct file *file;
1153         int retval;
1154         int i;
1155
1156         retval = -ENOMEM;
1157         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1158         if (!bprm)
1159                 goto out_ret;
1160
1161         file = open_exec(filename);
1162         retval = PTR_ERR(file);
1163         if (IS_ERR(file))
1164                 goto out_kfree;
1165
1166         sched_exec();
1167
1168         bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1169
1170         bprm->file = file;
1171         bprm->filename = filename;
1172         bprm->interp = filename;
1173         bprm->mm = mm_alloc();
1174         retval = -ENOMEM;
1175         if (!bprm->mm)
1176                 goto out_file;
1177
1178         retval = init_new_context(current, bprm->mm);
1179         if (retval < 0)
1180                 goto out_mm;
1181
1182         bprm->argc = count(argv, bprm->p / sizeof(void *));
1183         if ((retval = bprm->argc) < 0)
1184                 goto out_mm;
1185
1186         bprm->envc = count(envp, bprm->p / sizeof(void *));
1187         if ((retval = bprm->envc) < 0)
1188                 goto out_mm;
1189
1190         retval = security_bprm_alloc(bprm);
1191         if (retval)
1192                 goto out;
1193
1194         retval = prepare_binprm(bprm);
1195         if (retval < 0)
1196                 goto out;
1197
1198         retval = copy_strings_kernel(1, &bprm->filename, bprm);
1199         if (retval < 0)
1200                 goto out;
1201
1202         bprm->exec = bprm->p;
1203         retval = copy_strings(bprm->envc, envp, bprm);
1204         if (retval < 0)
1205                 goto out;
1206
1207         retval = copy_strings(bprm->argc, argv, bprm);
1208         if (retval < 0)
1209                 goto out;
1210
1211         retval = search_binary_handler(bprm,regs);
1212         if (retval >= 0) {
1213                 free_arg_pages(bprm);
1214
1215                 /* execve success */
1216                 security_bprm_free(bprm);
1217                 acct_update_integrals(current);
1218                 kfree(bprm);
1219                 return retval;
1220         }
1221
1222 out:
1223         /* Something went wrong, return the inode and free the argument pages*/
1224         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1225                 struct page * page = bprm->page[i];
1226                 if (page)
1227                         __free_page(page);
1228         }
1229
1230         if (bprm->security)
1231                 security_bprm_free(bprm);
1232
1233 out_mm:
1234         if (bprm->mm)
1235                 mmdrop(bprm->mm);
1236
1237 out_file:
1238         if (bprm->file) {
1239                 allow_write_access(bprm->file);
1240                 fput(bprm->file);
1241         }
1242
1243 out_kfree:
1244         kfree(bprm);
1245
1246 out_ret:
1247         return retval;
1248 }
1249
1250 int set_binfmt(struct linux_binfmt *new)
1251 {
1252         struct linux_binfmt *old = current->binfmt;
1253
1254         if (new) {
1255                 if (!try_module_get(new->module))
1256                         return -1;
1257         }
1258         current->binfmt = new;
1259         if (old)
1260                 module_put(old->module);
1261         return 0;
1262 }
1263
1264 EXPORT_SYMBOL(set_binfmt);
1265
1266 #define CORENAME_MAX_SIZE 64
1267
1268 /* format_corename will inspect the pattern parameter, and output a
1269  * name into corename, which must have space for at least
1270  * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1271  */
1272 static void format_corename(char *corename, const char *pattern, long signr)
1273 {
1274         const char *pat_ptr = pattern;
1275         char *out_ptr = corename;
1276         char *const out_end = corename + CORENAME_MAX_SIZE;
1277         int rc;
1278         int pid_in_pattern = 0;
1279
1280         /* Repeat as long as we have more pattern to process and more output
1281            space */
1282         while (*pat_ptr) {
1283                 if (*pat_ptr != '%') {
1284                         if (out_ptr == out_end)
1285                                 goto out;
1286                         *out_ptr++ = *pat_ptr++;
1287                 } else {
1288                         switch (*++pat_ptr) {
1289                         case 0:
1290                                 goto out;
1291                         /* Double percent, output one percent */
1292                         case '%':
1293                                 if (out_ptr == out_end)
1294                                         goto out;
1295                                 *out_ptr++ = '%';
1296                                 break;
1297                         /* pid */
1298                         case 'p':
1299                                 pid_in_pattern = 1;
1300                                 rc = snprintf(out_ptr, out_end - out_ptr,
1301                                               "%d", current->tgid);
1302                                 if (rc > out_end - out_ptr)
1303                                         goto out;
1304                                 out_ptr += rc;
1305                                 break;
1306                         /* uid */
1307                         case 'u':
1308                                 rc = snprintf(out_ptr, out_end - out_ptr,
1309                                               "%d", current->uid);
1310                                 if (rc > out_end - out_ptr)
1311                                         goto out;
1312                                 out_ptr += rc;
1313                                 break;
1314                         /* gid */
1315                         case 'g':
1316                                 rc = snprintf(out_ptr, out_end - out_ptr,
1317                                               "%d", current->gid);
1318                                 if (rc > out_end - out_ptr)
1319                                         goto out;
1320                                 out_ptr += rc;
1321                                 break;
1322                         /* signal that caused the coredump */
1323                         case 's':
1324                                 rc = snprintf(out_ptr, out_end - out_ptr,
1325                                               "%ld", signr);
1326                                 if (rc > out_end - out_ptr)
1327                                         goto out;
1328                                 out_ptr += rc;
1329                                 break;
1330                         /* UNIX time of coredump */
1331                         case 't': {
1332                                 struct timeval tv;
1333                                 do_gettimeofday(&tv);
1334                                 rc = snprintf(out_ptr, out_end - out_ptr,
1335                                               "%lu", tv.tv_sec);
1336                                 if (rc > out_end - out_ptr)
1337                                         goto out;
1338                                 out_ptr += rc;
1339                                 break;
1340                         }
1341                         /* hostname */
1342                         case 'h':
1343                                 down_read(&uts_sem);
1344                                 rc = snprintf(out_ptr, out_end - out_ptr,
1345                                               "%s", system_utsname.nodename);
1346                                 up_read(&uts_sem);
1347                                 if (rc > out_end - out_ptr)
1348                                         goto out;
1349                                 out_ptr += rc;
1350                                 break;
1351                         /* executable */
1352                         case 'e':
1353                                 rc = snprintf(out_ptr, out_end - out_ptr,
1354                                               "%s", current->comm);
1355                                 if (rc > out_end - out_ptr)
1356                                         goto out;
1357                                 out_ptr += rc;
1358                                 break;
1359                         default:
1360                                 break;
1361                         }
1362                         ++pat_ptr;
1363                 }
1364         }
1365         /* Backward compatibility with core_uses_pid:
1366          *
1367          * If core_pattern does not include a %p (as is the default)
1368          * and core_uses_pid is set, then .%pid will be appended to
1369          * the filename */
1370         if (!pid_in_pattern
1371             && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1372                 rc = snprintf(out_ptr, out_end - out_ptr,
1373                               ".%d", current->tgid);
1374                 if (rc > out_end - out_ptr)
1375                         goto out;
1376                 out_ptr += rc;
1377         }
1378       out:
1379         *out_ptr = 0;
1380 }
1381
1382 static void zap_threads (struct mm_struct *mm)
1383 {
1384         struct task_struct *g, *p;
1385         struct task_struct *tsk = current;
1386         struct completion *vfork_done = tsk->vfork_done;
1387         int traced = 0;
1388
1389         /*
1390          * Make sure nobody is waiting for us to release the VM,
1391          * otherwise we can deadlock when we wait on each other
1392          */
1393         if (vfork_done) {
1394                 tsk->vfork_done = NULL;
1395                 complete(vfork_done);
1396         }
1397
1398         read_lock(&tasklist_lock);
1399         do_each_thread(g,p)
1400                 if (mm == p->mm && p != tsk) {
1401                         force_sig_specific(SIGKILL, p);
1402                         mm->core_waiters++;
1403                         if (unlikely(p->ptrace) &&
1404                             unlikely(p->parent->mm == mm))
1405                                 traced = 1;
1406                 }
1407         while_each_thread(g,p);
1408
1409         read_unlock(&tasklist_lock);
1410
1411         if (unlikely(traced)) {
1412                 /*
1413                  * We are zapping a thread and the thread it ptraces.
1414                  * If the tracee went into a ptrace stop for exit tracing,
1415                  * we could deadlock since the tracer is waiting for this
1416                  * coredump to finish.  Detach them so they can both die.
1417                  */
1418                 write_lock_irq(&tasklist_lock);
1419                 do_each_thread(g,p) {
1420                         if (mm == p->mm && p != tsk &&
1421                             p->ptrace && p->parent->mm == mm) {
1422                                 __ptrace_detach(p, 0);
1423                         }
1424                 } while_each_thread(g,p);
1425                 write_unlock_irq(&tasklist_lock);
1426         }
1427 }
1428
1429 static void coredump_wait(struct mm_struct *mm)
1430 {
1431         DECLARE_COMPLETION(startup_done);
1432         int core_waiters;
1433
1434         mm->core_startup_done = &startup_done;
1435
1436         zap_threads(mm);
1437         core_waiters = mm->core_waiters;
1438         up_write(&mm->mmap_sem);
1439
1440         if (core_waiters)
1441                 wait_for_completion(&startup_done);
1442         BUG_ON(mm->core_waiters);
1443 }
1444
1445 int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1446 {
1447         char corename[CORENAME_MAX_SIZE + 1];
1448         struct mm_struct *mm = current->mm;
1449         struct linux_binfmt * binfmt;
1450         struct inode * inode;
1451         struct file * file;
1452         int retval = 0;
1453         int fsuid = current->fsuid;
1454         int flag = 0;
1455
1456         binfmt = current->binfmt;
1457         if (!binfmt || !binfmt->core_dump)
1458                 goto fail;
1459         down_write(&mm->mmap_sem);
1460         if (!mm->dumpable) {
1461                 up_write(&mm->mmap_sem);
1462                 goto fail;
1463         }
1464
1465         /*
1466          *      We cannot trust fsuid as being the "true" uid of the
1467          *      process nor do we know its entire history. We only know it
1468          *      was tainted so we dump it as root in mode 2.
1469          */
1470         if (mm->dumpable == 2) {        /* Setuid core dump mode */
1471                 flag = O_EXCL;          /* Stop rewrite attacks */
1472                 current->fsuid = 0;     /* Dump root private */
1473         }
1474         mm->dumpable = 0;
1475
1476         retval = -EAGAIN;
1477         spin_lock_irq(&current->sighand->siglock);
1478         if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
1479                 current->signal->flags = SIGNAL_GROUP_EXIT;
1480                 current->signal->group_exit_code = exit_code;
1481                 current->signal->group_stop_count = 0;
1482                 retval = 0;
1483         }
1484         spin_unlock_irq(&current->sighand->siglock);
1485         if (retval) {
1486                 up_write(&mm->mmap_sem);
1487                 goto fail;
1488         }
1489
1490         init_completion(&mm->core_done);
1491         coredump_wait(mm);
1492
1493         /*
1494          * Clear any false indication of pending signals that might
1495          * be seen by the filesystem code called to write the core file.
1496          */
1497         clear_thread_flag(TIF_SIGPENDING);
1498
1499         if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1500                 goto fail_unlock;
1501
1502         /*
1503          * lock_kernel() because format_corename() is controlled by sysctl, which
1504          * uses lock_kernel()
1505          */
1506         lock_kernel();
1507         format_corename(corename, core_pattern, signr);
1508         unlock_kernel();
1509         file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600);
1510         if (IS_ERR(file))
1511                 goto fail_unlock;
1512         inode = file->f_dentry->d_inode;
1513         if (inode->i_nlink > 1)
1514                 goto close_fail;        /* multiple links - don't dump */
1515         if (d_unhashed(file->f_dentry))
1516                 goto close_fail;
1517
1518         if (!S_ISREG(inode->i_mode))
1519                 goto close_fail;
1520         if (!file->f_op)
1521                 goto close_fail;
1522         if (!file->f_op->write)
1523                 goto close_fail;
1524         if (do_truncate(file->f_dentry, 0, 0, file) != 0)
1525                 goto close_fail;
1526
1527         retval = binfmt->core_dump(signr, regs, file);
1528
1529         if (retval)
1530                 current->signal->group_exit_code |= 0x80;
1531 close_fail:
1532         filp_close(file, NULL);
1533 fail_unlock:
1534         current->fsuid = fsuid;
1535         complete_all(&mm->core_done);
1536 fail:
1537         return retval;
1538 }