ClabureDB: Classified Bug-Reports Database

   /*
    *  linux/fs/exec.c
    *
    *  Copyright (C) 1991, 1992  Linus Torvalds
    */
   
   /*
    * #!-checking implemented by tytso.
    */
  /*
   * Demand-loading implemented 01.12.91 - no need to read anything but
   * the header into memory. The inode of the executable is put into
   * "current->executable", and page faults do the actual loading. Clean.
   *
   * Once more I can proudly say that linux stood up to being changed: it
   * was less than 2 hours work to get demand-loading completely implemented.
   *
   * Demand loading changed July 1993 by Eric Youngdale.   Use mmap instead,
   * current->executable is only used by the procfs.  This allows a dispatch
   * table to check for several different types  of binary formats.  We keep
   * trying until we recognize the file or we run out of supported binary
   * formats. 
   */
  
  #include <linux/slab.h>
  #include <linux/file.h>
  #include <linux/fdtable.h>
  #include <linux/mm.h>
  #include <linux/stat.h>
  #include <linux/fcntl.h>
  #include <linux/smp_lock.h>
  #include <linux/swap.h>
  #include <linux/string.h>
  #include <linux/init.h>
  #include <linux/pagemap.h>
  #include <linux/highmem.h>
  #include <linux/spinlock.h>
  #include <linux/key.h>
  #include <linux/personality.h>
  #include <linux/binfmts.h>
  #include <linux/utsname.h>
  #include <linux/pid_namespace.h>
  #include <linux/module.h>
  #include <linux/namei.h>
  #include <linux/proc_fs.h>
  #include <linux/mount.h>
  #include <linux/security.h>
  #include <linux/syscalls.h>
  #include <linux/tsacct_kern.h>
  #include <linux/cn_proc.h>
  #include <linux/audit.h>
  #include <linux/tracehook.h>
  #include <linux/kmod.h>
  
  #include <asm/uaccess.h>
  #include <asm/mmu_context.h>
  #include <asm/tlb.h>
  
  #ifdef __alpha__
  /* for /sbin/loader handling in search_binary_handler() */
  #include <linux/a.out.h>
  #endif
  
  int core_uses_pid;
  char core_pattern[CORENAME_MAX_SIZE] = "core";
  int suid_dumpable = 0;
  
  /* The maximal length of core_pattern is also specified in sysctl.c */
  
  static LIST_HEAD(formats);
  static DEFINE_RWLOCK(binfmt_lock);
  
  int register_binfmt(struct linux_binfmt * fmt)
  {
          if (!fmt)
                  return -EINVAL;
          write_lock(&binfmt_lock);
          list_add(&fmt->lh, &formats);
          write_unlock(&binfmt_lock);
          return 0;        
  }
  
  EXPORT_SYMBOL(register_binfmt);
  
  void unregister_binfmt(struct linux_binfmt * fmt)
  {
          write_lock(&binfmt_lock);
          list_del(&fmt->lh);
          write_unlock(&binfmt_lock);
  }
  
  EXPORT_SYMBOL(unregister_binfmt);
  
  static inline void put_binfmt(struct linux_binfmt * fmt)
  {
          module_put(fmt->module);
  }
  
  /*
  * Note that a shared library must be both readable and executable due to
  * security reasons.
  *
  * Also note that we take the address to load from from the file itself.
  */
 asmlinkage long sys_uselib(const char __user * library)
 {
         struct file *file;
         struct nameidata nd;
         char *tmp = getname(library);
         int error = PTR_ERR(tmp);
 
         if (!IS_ERR(tmp)) {
                 error = path_lookup_open(AT_FDCWD, tmp,
                                          LOOKUP_FOLLOW, &nd,
                                          FMODE_READ|FMODE_EXEC);
                 putname(tmp);
         }
         if (error)
                 goto out;
 
         error = -EINVAL;
         if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
                 goto exit;
 
         error = -EACCES;
         if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
                 goto exit;
 
         error = vfs_permission(&nd, MAY_READ | MAY_EXEC | MAY_OPEN);
         if (error)
                 goto exit;
 
         file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
         error = PTR_ERR(file);
         if (IS_ERR(file))
                 goto out;
 
         error = -ENOEXEC;
         if(file->f_op) {
                 struct linux_binfmt * fmt;
 
                 read_lock(&binfmt_lock);
                 list_for_each_entry(fmt, &formats, lh) {
                         if (!fmt->load_shlib)
                                 continue;
                         if (!try_module_get(fmt->module))
                                 continue;
                         read_unlock(&binfmt_lock);
                         error = fmt->load_shlib(file);
                         read_lock(&binfmt_lock);
                         put_binfmt(fmt);
                         if (error != -ENOEXEC)
                                 break;
                 }
                 read_unlock(&binfmt_lock);
         }
         fput(file);
 out:
           return error;
 exit:
         release_open_intent(&nd);
         path_put(&nd.path);
         goto out;
 }
 
 #ifdef CONFIG_MMU
 
 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                 int write)
 {
         struct page *page;
         int ret;
 
 #ifdef CONFIG_STACK_GROWSUP
         if (write) {
                 ret = expand_stack_downwards(bprm->vma, pos);
                 if (ret < 0)
                         return NULL;
         }
 #endif
         ret = get_user_pages(current, bprm->mm, pos,
                         1, write, 1, &page, NULL);
         if (ret <= 0)
                 return NULL;
 
         if (write) {
                 unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
                 struct rlimit *rlim;
 
                 /*
                  * We've historically supported up to 32 pages (ARG_MAX)
                  * of argument strings even with small stacks
                  */
                 if (size <= ARG_MAX)
                         return page;
 
                 /*
                  * Limit to 1/4-th the stack size for the argv+env strings.
                  * This ensures that:
                  *  - the remaining binfmt code will not run out of stack space,
                  *  - the program will have a reasonable amount of stack left
                  *    to work from.
                  */
                 rlim = current->signal->rlim;
                 if (size > rlim[RLIMIT_STACK].rlim_cur / 4) {
                         put_page(page);
                         return NULL;
                 }
         }
 
         return page;
 }
 
 static void put_arg_page(struct page *page)
 {
         put_page(page);
 }
 
 static void free_arg_page(struct linux_binprm *bprm, int i)
 {
 }
 
 static void free_arg_pages(struct linux_binprm *bprm)
 {
 }
 
 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
                 struct page *page)
 {
         flush_cache_page(bprm->vma, pos, page_to_pfn(page));
 }
 
 static int __bprm_mm_init(struct linux_binprm *bprm)
 {
         int err = -ENOMEM;
         struct vm_area_struct *vma = NULL;
         struct mm_struct *mm = bprm->mm;
 
         bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
         if (!vma)
                 goto err;
 
         down_write(&mm->mmap_sem);
         vma->vm_mm = mm;
 
         /*
          * Place the stack at the largest stack address the architecture
          * supports. Later, we'll move this to an appropriate place. We don't
          * use STACK_TOP because that can depend on attributes which aren't
          * configured yet.
          */
         vma->vm_end = STACK_TOP_MAX;
         vma->vm_start = vma->vm_end - PAGE_SIZE;
 
         vma->vm_flags = VM_STACK_FLAGS;
         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
         err = insert_vm_struct(mm, vma);
         if (err) {
                 up_write(&mm->mmap_sem);
                 goto err;
         }
 
         mm->stack_vm = mm->total_vm = 1;
         up_write(&mm->mmap_sem);
 
         bprm->p = vma->vm_end - sizeof(void *);
 
         return 0;
 
 err:
         if (vma) {
                 bprm->vma = NULL;
                 kmem_cache_free(vm_area_cachep, vma);
         }
 
         return err;
 }
 
 static bool valid_arg_len(struct linux_binprm *bprm, long len)
 {
         return len <= MAX_ARG_STRLEN;
 }
 
 #else
 
 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                 int write)
 {
         struct page *page;
 
         page = bprm->page[pos / PAGE_SIZE];
         if (!page && write) {
                 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
                 if (!page)
                         return NULL;
                 bprm->page[pos / PAGE_SIZE] = page;
         }
 
         return page;
 }
 
 static void put_arg_page(struct page *page)
 {
 }
 
 static void free_arg_page(struct linux_binprm *bprm, int i)
 {
         if (bprm->page[i]) {
                 __free_page(bprm->page[i]);
                 bprm->page[i] = NULL;
         }
 }
 
 static void free_arg_pages(struct linux_binprm *bprm)
 {
         int i;
 
         for (i = 0; i < MAX_ARG_PAGES; i++)
                 free_arg_page(bprm, i);
 }
 
 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
                 struct page *page)
 {
 }
 
 static int __bprm_mm_init(struct linux_binprm *bprm)
 {
         bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
         return 0;
 }
 
 static bool valid_arg_len(struct linux_binprm *bprm, long len)
 {
         return len <= bprm->p;
 }
 
 #endif /* CONFIG_MMU */
 
 /*
  * Create a new mm_struct and populate it with a temporary stack
  * vm_area_struct.  We don't have enough context at this point to set the stack
  * flags, permissions, and offset, so we use temporary values.  We'll update
  * them later in setup_arg_pages().
  */
 int bprm_mm_init(struct linux_binprm *bprm)
 {
         int err;
         struct mm_struct *mm = NULL;
 
         bprm->mm = mm = mm_alloc();
         err = -ENOMEM;
         if (!mm)
                 goto err;
 
         err = init_new_context(current, mm);
         if (err)
                 goto err;
 
         err = __bprm_mm_init(bprm);
         if (err)
                 goto err;
 
         return 0;
 
 err:
         if (mm) {
                 bprm->mm = NULL;
                 mmdrop(mm);
         }
 
         return err;
 }
 
 /*
  * count() counts the number of strings in array ARGV.
  */
 static int count(char __user * __user * argv, int max)
 {
         int i = 0;
 
         if (argv != NULL) {
                 for (;;) {
                         char __user * p;
 
                         if (get_user(p, argv))
                                 return -EFAULT;
                         if (!p)
                                 break;
                         argv++;
                         if (i++ >= max)
                                 return -E2BIG;
                         cond_resched();
                 }
         }
         return i;
 }
 
 /*
  * 'copy_strings()' copies argument/environment strings from the old
  * processes's memory to the new process's stack.  The call to get_user_pages()
  * ensures the destination page is created and not swapped out.
  */
 static int copy_strings(int argc, char __user * __user * argv,
                         struct linux_binprm *bprm)
 {
         struct page *kmapped_page = NULL;
         char *kaddr = NULL;
         unsigned long kpos = 0;
         int ret;
 
         while (argc-- > 0) {
                 char __user *str;
                 int len;
                 unsigned long pos;
 
                 if (get_user(str, argv+argc) ||
                                 !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
                         ret = -EFAULT;
                         goto out;
                 }
 
                 if (!valid_arg_len(bprm, len)) {
                         ret = -E2BIG;
                         goto out;
                 }
 
                 /* We're going to work our way backwords. */
                 pos = bprm->p;
                 str += len;
                 bprm->p -= len;
 
                 while (len > 0) {
                         int offset, bytes_to_copy;
 
                         offset = pos % PAGE_SIZE;
                         if (offset == 0)
                                 offset = PAGE_SIZE;
 
                         bytes_to_copy = offset;
                         if (bytes_to_copy > len)
                                 bytes_to_copy = len;
 
                         offset -= bytes_to_copy;
                         pos -= bytes_to_copy;
                         str -= bytes_to_copy;
                         len -= bytes_to_copy;
 
                         if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
                                 struct page *page;
 
                                 page = get_arg_page(bprm, pos, 1);
                                 if (!page) {
                                         ret = -E2BIG;
                                         goto out;
                                 }
 
                                 if (kmapped_page) {
                                         flush_kernel_dcache_page(kmapped_page);
                                         kunmap(kmapped_page);
                                         put_arg_page(kmapped_page);
                                 }
                                 kmapped_page = page;
                                 kaddr = kmap(kmapped_page);
                                 kpos = pos & PAGE_MASK;
                                 flush_arg_page(bprm, kpos, kmapped_page);
                         }
                         if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
                                 ret = -EFAULT;
                                 goto out;
                         }
                 }
         }
         ret = 0;
 out:
         if (kmapped_page) {
                 flush_kernel_dcache_page(kmapped_page);
                 kunmap(kmapped_page);
                 put_arg_page(kmapped_page);
         }
         return ret;
 }
 
 /*
  * Like copy_strings, but get argv and its values from kernel memory.
  */
 int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
 {
         int r;
         mm_segment_t oldfs = get_fs();
         set_fs(KERNEL_DS);
         r = copy_strings(argc, (char __user * __user *)argv, bprm);
         set_fs(oldfs);
         return r;
 }
 EXPORT_SYMBOL(copy_strings_kernel);
 
 #ifdef CONFIG_MMU
 
 /*
  * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX.  Once
  * the binfmt code determines where the new stack should reside, we shift it to
  * its final location.  The process proceeds as follows:
  *
  * 1) Use shift to calculate the new vma endpoints.
  * 2) Extend vma to cover both the old and new ranges.  This ensures the
  *    arguments passed to subsequent functions are consistent.
  * 3) Move vma's page tables to the new range.
  * 4) Free up any cleared pgd range.
  * 5) Shrink the vma to cover only the new range.
  */
 static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 {
         struct mm_struct *mm = vma->vm_mm;
         unsigned long old_start = vma->vm_start;
         unsigned long old_end = vma->vm_end;
         unsigned long length = old_end - old_start;
         unsigned long new_start = old_start - shift;
         unsigned long new_end = old_end - shift;
         struct mmu_gather *tlb;
 
         BUG_ON(new_start > new_end);
 
         /*
          * ensure there are no vmas between where we want to go
          * and where we are
          */
         if (vma != find_vma(mm, new_start))
                 return -EFAULT;
 
         /*
          * cover the whole range: [new_start, old_end)
          */
         vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
 
         /*
          * move the page tables downwards, on failure we rely on
          * process cleanup to remove whatever mess we made.
          */
         if (length != move_page_tables(vma, old_start,
                                        vma, new_start, length))
                 return -ENOMEM;
 
         lru_add_drain();
         tlb = tlb_gather_mmu(mm, 0);
         if (new_end > old_start) {
                 /*
                  * when the old and new regions overlap clear from new_end.
                  */
                 free_pgd_range(tlb, new_end, old_end, new_end,
                         vma->vm_next ? vma->vm_next->vm_start : 0);
         } else {
                 /*
                  * otherwise, clean from old_start; this is done to not touch
                  * the address space in [new_end, old_start) some architectures
                  * have constraints on va-space that make this illegal (IA64) -
                  * for the others its just a little faster.
                  */
                 free_pgd_range(tlb, old_start, old_end, new_end,
                         vma->vm_next ? vma->vm_next->vm_start : 0);
         }
         tlb_finish_mmu(tlb, new_end, old_end);
 
         /*
          * shrink the vma to just the new range.
          */
         vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
 
         return 0;
 }
 
 #define EXTRA_STACK_VM_PAGES        20        /* random */
 
 /*
  * Finalizes the stack vm_area_struct. The flags and permissions are updated,
  * the stack is optionally relocated, and some extra space is added.
  */
 int setup_arg_pages(struct linux_binprm *bprm,
                     unsigned long stack_top,
                     int executable_stack)
 {
         unsigned long ret;
         unsigned long stack_shift;
         struct mm_struct *mm = current->mm;
         struct vm_area_struct *vma = bprm->vma;
         struct vm_area_struct *prev = NULL;
         unsigned long vm_flags;
         unsigned long stack_base;
 
 #ifdef CONFIG_STACK_GROWSUP
         /* Limit stack size to 1GB */
         stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
         if (stack_base > (1 << 30))
                 stack_base = 1 << 30;
 
         /* Make sure we didn't let the argument array grow too large. */
         if (vma->vm_end - vma->vm_start > stack_base)
                 return -ENOMEM;
 
         stack_base = PAGE_ALIGN(stack_top - stack_base);
 
         stack_shift = vma->vm_start - stack_base;
         mm->arg_start = bprm->p - stack_shift;
         bprm->p = vma->vm_end - stack_shift;
 #else
         stack_top = arch_align_stack(stack_top);
         stack_top = PAGE_ALIGN(stack_top);
         stack_shift = vma->vm_end - stack_top;
 
         bprm->p -= stack_shift;
         mm->arg_start = bprm->p;
 #endif
 
         if (bprm->loader)
                 bprm->loader -= stack_shift;
         bprm->exec -= stack_shift;
 
         down_write(&mm->mmap_sem);
         vm_flags = VM_STACK_FLAGS;
 
         /*
          * Adjust stack execute permissions; explicitly enable for
          * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
          * (arch default) otherwise.
          */
         if (unlikely(executable_stack == EXSTACK_ENABLE_X))
                 vm_flags |= VM_EXEC;
         else if (executable_stack == EXSTACK_DISABLE_X)
                 vm_flags &= ~VM_EXEC;
         vm_flags |= mm->def_flags;
 
         ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
                         vm_flags);
         if (ret)
                 goto out_unlock;
         BUG_ON(prev != vma);
 
         /* Move stack pages down in memory. */
         if (stack_shift) {
                 ret = shift_arg_pages(vma, stack_shift);
                 if (ret) {
                         up_write(&mm->mmap_sem);
                         return ret;
                 }
         }
 
 #ifdef CONFIG_STACK_GROWSUP
         stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
 #else
         stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
 #endif
         ret = expand_stack(vma, stack_base);
         if (ret)
                 ret = -EFAULT;
 
 out_unlock:
         up_write(&mm->mmap_sem);
         return 0;
 }
 EXPORT_SYMBOL(setup_arg_pages);
 
 #endif /* CONFIG_MMU */
 
 struct file *open_exec(const char *name)
 {
         struct nameidata nd;
         struct file *file;
         int err;
 
         err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd,
                                 FMODE_READ|FMODE_EXEC);
         if (err)
                 goto out;
 
         err = -EACCES;
         if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
                 goto out_path_put;
 
         if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
                 goto out_path_put;
 
         err = vfs_permission(&nd, MAY_EXEC | MAY_OPEN);
         if (err)
                 goto out_path_put;
 
         file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
         if (IS_ERR(file))
                 return file;
 
         err = deny_write_access(file);
         if (err) {
                 fput(file);
                 goto out;
         }
 
         return file;
 
  out_path_put:
         release_open_intent(&nd);
         path_put(&nd.path);
  out:
         return ERR_PTR(err);
 }
 EXPORT_SYMBOL(open_exec);
 
 int kernel_read(struct file *file, unsigned long offset,
         char *addr, unsigned long count)
 {
         mm_segment_t old_fs;
         loff_t pos = offset;
         int result;
 
         old_fs = get_fs();
         set_fs(get_ds());
         /* The cast to a user pointer is valid due to the set_fs() */
         result = vfs_read(file, (void __user *)addr, count, &pos);
         set_fs(old_fs);
         return result;
 }
 
 EXPORT_SYMBOL(kernel_read);
 
 static int exec_mmap(struct mm_struct *mm)
 {
         struct task_struct *tsk;
         struct mm_struct * old_mm, *active_mm;
 
         /* Notify parent that we're no longer interested in the old VM */
         tsk = current;
         old_mm = current->mm;
         mm_release(tsk, old_mm);
 
         if (old_mm) {
                 /*
                  * Make sure that if there is a core dump in progress
                  * for the old mm, we get out and die instead of going
                  * through with the exec.  We must hold mmap_sem around
                  * checking core_state and changing tsk->mm.
                  */
                 down_read(&old_mm->mmap_sem);
                 if (unlikely(old_mm->core_state)) {
                         up_read(&old_mm->mmap_sem);
                         return -EINTR;
                 }
         }
         task_lock(tsk);
         active_mm = tsk->active_mm;
         tsk->mm = mm;
         tsk->active_mm = mm;
         activate_mm(active_mm, mm);
         task_unlock(tsk);
         arch_pick_mmap_layout(mm);
         if (old_mm) {
                 up_read(&old_mm->mmap_sem);
                 BUG_ON(active_mm != old_mm);
                 mm_update_next_owner(old_mm);
                 mmput(old_mm);
                 return 0;
         }
         mmdrop(active_mm);
         return 0;
 }
 
 /*
  * This function makes sure the current process has its own signal table,
  * so that flush_signal_handlers can later reset the handlers without
  * disturbing other processes.  (Other processes might share the signal
  * table via the CLONE_SIGHAND option to clone().)
  */
 static int de_thread(struct task_struct *tsk)
 {
         struct signal_struct *sig = tsk->signal;
         struct sighand_struct *oldsighand = tsk->sighand;
         spinlock_t *lock = &oldsighand->siglock;
         struct task_struct *leader = NULL;
         int count;
 
         if (thread_group_empty(tsk))
                 goto no_thread_group;
 
         /*
          * Kill all other threads in the thread group.
          */
         spin_lock_irq(lock);
         if (signal_group_exit(sig)) {
                 /*
                  * Another group action in progress, just
                  * return so that the signal is processed.
                  */
                 spin_unlock_irq(lock);
                 return -EAGAIN;
         }
         sig->group_exit_task = tsk;
         zap_other_threads(tsk);
 
         /* Account for the thread group leader hanging around: */
         count = thread_group_leader(tsk) ? 1 : 2;
         sig->notify_count = count;
         while (atomic_read(&sig->count) > count) {
                 __set_current_state(TASK_UNINTERRUPTIBLE);
                 spin_unlock_irq(lock);
                 schedule();
                 spin_lock_irq(lock);
         }
         spin_unlock_irq(lock);
 
         /*
          * At this point all other threads have exited, all we have to
          * do is to wait for the thread group leader to become inactive,
          * and to assume its PID:
          */
         if (!thread_group_leader(tsk)) {
                 leader = tsk->group_leader;
 
                 sig->notify_count = -1;        /* for exit_notify() */
                 for (;;) {
                         write_lock_irq(&tasklist_lock);
                         if (likely(leader->exit_state))
                                 break;
                         __set_current_state(TASK_UNINTERRUPTIBLE);
                         write_unlock_irq(&tasklist_lock);
                         schedule();
                 }
 
                 /*
                  * The only record we have of the real-time age of a
                  * process, regardless of execs it's done, is start_time.
                  * All the past CPU time is accumulated in signal_struct
                  * from sister threads now dead.  But in this non-leader
                  * exec, nothing survives from the original leader thread,
                  * whose birth marks the true age of this process now.
                  * When we take on its identity by switching to its PID, we
                  * also take its birthdate (always earlier than our own).
                  */
                 tsk->start_time = leader->start_time;
 
                 BUG_ON(!same_thread_group(leader, tsk));
                 BUG_ON(has_group_leader_pid(tsk));
                 /*
                  * An exec() starts a new thread group with the
                  * TGID of the previous thread group. Rehash the
                  * two threads with a switched PID, and release
                  * the former thread group leader:
                  */
 
                 /* Become a process group leader with the old leader's pid.
                  * The old leader becomes a thread of the this thread group.
                  * Note: The old leader also uses this pid until release_task
                  *       is called.  Odd but simple and correct.
                  */
                 detach_pid(tsk, PIDTYPE_PID);
                 tsk->pid = leader->pid;
                 attach_pid(tsk, PIDTYPE_PID,  task_pid(leader));
                 transfer_pid(leader, tsk, PIDTYPE_PGID);
                 transfer_pid(leader, tsk, PIDTYPE_SID);
                 list_replace_rcu(&leader->tasks, &tsk->tasks);
 
                 tsk->group_leader = tsk;
                 leader->group_leader = tsk;
 
                 tsk->exit_signal = SIGCHLD;
 
                 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
                 leader->exit_state = EXIT_DEAD;
 
                 write_unlock_irq(&tasklist_lock);
         }
 
         sig->group_exit_task = NULL;
         sig->notify_count = 0;
 
 no_thread_group:
         exit_itimers(sig);
         flush_itimer_signals();
         if (leader)
                 release_task(leader);
 
         if (atomic_read(&oldsighand->count) != 1) {
                 struct sighand_struct *newsighand;
                 /*
                  * This ->sighand is shared with the CLONE_SIGHAND
                  * but not CLONE_THREAD task, switch to the new one.
                  */
                 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
                 if (!newsighand)
                         return -ENOMEM;
 
                 atomic_set(&newsighand->count, 1);
                 memcpy(newsighand->action, oldsighand->action,
                        sizeof(newsighand->action));
 
                 write_lock_irq(&tasklist_lock);
                 spin_lock(&oldsighand->siglock);
                 rcu_assign_pointer(tsk->sighand, newsighand);
                 spin_unlock(&oldsighand->siglock);
                 write_unlock_irq(&tasklist_lock);
 
                 __cleanup_sighand(oldsighand);
         }
 
         BUG_ON(!thread_group_leader(tsk));
         return 0;
 }
 
 /*
  * These functions flushes out all traces of the currently running executable
  * so that a new one can be started
  */
 static void flush_old_files(struct files_struct * files)
 {
         long j = -1;
         struct fdtable *fdt;
 
         spin_lock(&files->file_lock);
         for (;;) {
                 unsigned long set, i;
 
                 j++;
                 i = j * __NFDBITS;
                 fdt = files_fdtable(files);
                 if (i >= fdt->max_fds)
                         break;
                 set = fdt->close_on_exec->fds_bits[j];
                 if (!set)
                         continue;
                 fdt->close_on_exec->fds_bits[j] = 0;
                 spin_unlock(&files->file_lock);
                 for ( ; set ; i++,set >>= 1) {
                         if (set & 1) {
                                 sys_close(i);
                         }
                 }
                 spin_lock(&files->file_lock);
 
         }
         spin_unlock(&files->file_lock);
 }
 
 char *get_task_comm(char *buf, struct task_struct *tsk)
 {
         /* buf must be at least sizeof(tsk->comm) in size */
         task_lock(tsk);
         strncpy(buf, tsk->comm, sizeof(tsk->comm));
         task_unlock(tsk);
         return buf;
 }
 
 void set_task_comm(struct task_struct *tsk, char *buf)
 {
         task_lock(tsk);
         strlcpy(tsk->comm, buf, sizeof(tsk->comm));
         task_unlock(tsk);
 }
 
 int flush_old_exec(struct linux_binprm * bprm)
 {
         char * name;
         int i, ch, retval;
         char tcomm[sizeof(current->comm)];
 
         /*
          * Make sure we have a private signal table and that
          * we are unassociated from the previous thread group.
          */
         retval = de_thread(current);
         if (retval)
                 goto out;
 
         set_mm_exe_file(bprm->mm, bprm->file);
 
         /*
          * Release all of the old mmap stuff
          */
         retval = exec_mmap(bprm->mm);
         if (retval)
                 goto out;
 
         bprm->mm = NULL;                /* We're using it now */
 
         /* This is the point of no return */
         current->sas_ss_sp = current->sas_ss_size = 0;
 
         if (current->euid == current->uid && current->egid == current->gid)
                 set_dumpable(current->mm, 1);
         else
                 set_dumpable(current->mm, suid_dumpable);
 
         name = bprm->filename;
 
         /* Copies the binary name from after last slash */
         for (i=0; (ch = *(name++)) != '\0';) {
                 if (ch == '/')
                         i = 0; /* overwrite what we wrote */
                 else
                         if (i < (sizeof(tcomm) - 1))
                                 tcomm[i++] = ch;
         }
         tcomm[i] = '\0';
         set_task_comm(current, tcomm);

        current->flags &= ~PF_RANDOMIZE;
        flush_thread();

        /* Set the new mm task size. We have to do that late because it may
         * depend on TIF_32BIT which is only updated in flush_thread() on
         * some architectures like powerpc
         */
        current->mm->task_size = TASK_SIZE;

        if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) {
                suid_keys(current);
                set_dumpable(current->mm, suid_dumpable);
                current->pdeath_signal = 0;
        } else if (file_permission(bprm->file, MAY_READ) ||
                        (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
                suid_keys(current);
                set_dumpable(current->mm, suid_dumpable);
        }

        /* An exec changes our domain. We are no longer part of the thread
           group */

        current->self_exec_id++;
                        
        flush_signal_handlers(current, 0);
        flush_old_files(current->files);

        return 0;

out:
        return retval;
}

EXPORT_SYMBOL(flush_old_exec);

/* 
 * Fill the binprm structure from the inode. 
 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
 */
int prepare_binprm(struct linux_binprm *bprm)
{
        int mode;
        struct inode * inode = bprm->file->f_path.dentry->d_inode;
        int retval;

        mode = inode->i_mode;
        if (bprm->file->f_op == NULL)
                return -EACCES;

        bprm->e_uid = current->euid;
        bprm->e_gid = current->egid;

        if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
                /* Set-uid? */
                if (mode & S_ISUID) {
                        current->personality &= ~PER_CLEAR_ON_SETID;
                        bprm->e_uid = inode->i_uid;
                }

                /* Set-gid? */
                /*
                 * If setgid is set but no group execute bit then this
                 * is a candidate for mandatory locking, not a setgid
                 * executable.
                 */
                if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
                        current->personality &= ~PER_CLEAR_ON_SETID;
                        bprm->e_gid = inode->i_gid;
                }
        }

        /* fill in binprm security blob */
        retval = security_bprm_set(bprm);
        if (retval)
                return retval;

        memset(bprm->buf,0,BINPRM_BUF_SIZE);
        return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
}

EXPORT_SYMBOL(prepare_binprm);

static int unsafe_exec(struct task_struct *p)
{
        int unsafe = tracehook_unsafe_exec(p);

        if (atomic_read(&p->fs->count) > 1 ||
            atomic_read(&p->files->count) > 1 ||
            atomic_read(&p->sighand->count) > 1)
                unsafe |= LSM_UNSAFE_SHARE;

        return unsafe;
}

void compute_creds(struct linux_binprm *bprm)
{
        int unsafe;

        if (bprm->e_uid != current->uid) {
                suid_keys(current);
                current->pdeath_signal = 0;
        }
        exec_keys(current);

        task_lock(current);
        unsafe = unsafe_exec(current);
        security_bprm_apply_creds(bprm, unsafe);
        task_unlock(current);
        security_bprm_post_apply_creds(bprm);
}
EXPORT_SYMBOL(compute_creds);

/*
 * Arguments are '\0' separated strings found at the location bprm->p
 * points to; chop off the first by relocating brpm->p to right after
 * the first '\0' encountered.
 */
int remove_arg_zero(struct linux_binprm *bprm)
{
        int ret = 0;
        unsigned long offset;
        char *kaddr;
        struct page *page;

        if (!bprm->argc)
                return 0;

        do {
                offset = bprm->p & ~PAGE_MASK;
                page = get_arg_page(bprm, bprm->p, 0);
                if (!page) {
                        ret = -EFAULT;
                        goto out;
                }
                kaddr = kmap_atomic(page, KM_USER0);

                for (; offset < PAGE_SIZE && kaddr[offset];
                                offset++, bprm->p++)
                        ;

                kunmap_atomic(kaddr, KM_USER0);
                put_arg_page(page);

                if (offset == PAGE_SIZE)
                        free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
        } while (offset == PAGE_SIZE);

        bprm->p++;
        bprm->argc--;
        ret = 0;

out:
        return ret;
}
EXPORT_SYMBOL(remove_arg_zero);

/*
 * cycle the list of binary formats handler, until one recognizes the image
 */
int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
{
        unsigned int depth = bprm->recursion_depth;
        int try,retval;
        struct linux_binfmt *fmt;
#ifdef __alpha__
        /* handle /sbin/loader.. */
        {
            struct exec * eh = (struct exec *) bprm->buf;

            if (!bprm->loader && eh->fh.f_magic == 0x183 &&
                (eh->fh.f_flags & 0x3000) == 0x3000)
            {
                struct file * file;
                unsigned long loader;

                allow_write_access(bprm->file);
                fput(bprm->file);
                bprm->file = NULL;

                loader = bprm->vma->vm_end - sizeof(void *);

                file = open_exec("/sbin/loader");
                retval = PTR_ERR(file);
                if (IS_ERR(file))
                        return retval;

                /* Remember if the application is TASO.  */
                bprm->taso = eh->ah.entry < 0x100000000UL;

                bprm->file = file;
                bprm->loader = loader;
                retval = prepare_binprm(bprm);
                if (retval<0)
                        return retval;
                /* should call search_binary_handler recursively here,
                   but it does not matter */
            }
        }
#endif
        retval = security_bprm_check(bprm);
        if (retval)
                return retval;

        /* kernel module loader fixup */
        /* so we don't try to load run modprobe in kernel space. */
        set_fs(USER_DS);

        retval = audit_bprm(bprm);
        if (retval)
                return retval;

        retval = -ENOENT;
        for (try=0; try<2; try++) {
                read_lock(&binfmt_lock);
                list_for_each_entry(fmt, &formats, lh) {
                        int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
                        if (!fn)
                                continue;
                        if (!try_module_get(fmt->module))
                                continue;
                        read_unlock(&binfmt_lock);
                        retval = fn(bprm, regs);
                        /*
                         * Restore the depth counter to its starting value
                         * in this call, so we don't have to rely on every
                         * load_binary function to restore it on return.
                         */
                        bprm->recursion_depth = depth;
                        if (retval >= 0) {
                                if (depth == 0)
                                        tracehook_report_exec(fmt, bprm, regs);
                                put_binfmt(fmt);
                                allow_write_access(bprm->file);
                                if (bprm->file)
                                        fput(bprm->file);
                                bprm->file = NULL;
                                current->did_exec = 1;
                                proc_exec_connector(current);
                                return retval;
                        }
                        read_lock(&binfmt_lock);
                        put_binfmt(fmt);
                        if (retval != -ENOEXEC || bprm->mm == NULL)
                                break;
                        if (!bprm->file) {
                                read_unlock(&binfmt_lock);
                                return retval;
                        }
                }
                read_unlock(&binfmt_lock);
                if (retval != -ENOEXEC || bprm->mm == NULL) {
                        break;
#ifdef CONFIG_MODULES
                } else {
#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
                        if (printable(bprm->buf[0]) &&
                            printable(bprm->buf[1]) &&
                            printable(bprm->buf[2]) &&
                            printable(bprm->buf[3]))
                                break; /* -ENOEXEC */
                        request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
#endif
                }
        }
        return retval;
}

EXPORT_SYMBOL(search_binary_handler);

void free_bprm(struct linux_binprm *bprm)
{
        free_arg_pages(bprm);
        kfree(bprm);
}

/*
 * sys_execve() executes a new program.
 */
int do_execve(char * filename,
        char __user *__user *argv,
        char __user *__user *envp,
        struct pt_regs * regs)
{
        struct linux_binprm *bprm;
        struct file *file;
        struct files_struct *displaced;
        int retval;

        retval = unshare_files(&displaced);
        if (retval)
                goto out_ret;

        retval = -ENOMEM;
        bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
        if (!bprm)
                goto out_files;

        file = open_exec(filename);
        retval = PTR_ERR(file);
        if (IS_ERR(file))
                goto out_kfree;

        sched_exec();

        bprm->file = file;
        bprm->filename = filename;
        bprm->interp = filename;

        retval = bprm_mm_init(bprm);
        if (retval)
                goto out_file;

        bprm->argc = count(argv, MAX_ARG_STRINGS);
        if ((retval = bprm->argc) < 0)
                goto out_mm;

        bprm->envc = count(envp, MAX_ARG_STRINGS);
        if ((retval = bprm->envc) < 0)
                goto out_mm;

        retval = security_bprm_alloc(bprm);
        if (retval)
                goto out;

        retval = prepare_binprm(bprm);
        if (retval < 0)
                goto out;

        retval = copy_strings_kernel(1, &bprm->filename, bprm);
        if (retval < 0)
                goto out;

        bprm->exec = bprm->p;
        retval = copy_strings(bprm->envc, envp, bprm);
        if (retval < 0)
                goto out;

        retval = copy_strings(bprm->argc, argv, bprm);
        if (retval < 0)
                goto out;

        current->flags &= ~PF_KTHREAD;
        retval = search_binary_handler(bprm,regs);
        if (retval >= 0) {
                /* execve success */
                security_bprm_free(bprm);
                acct_update_integrals(current);
                free_bprm(bprm);
                if (displaced)
                        put_files_struct(displaced);
                return retval;
        }

out:
        if (bprm->security)
                security_bprm_free(bprm);

out_mm:
        if (bprm->mm)
                mmput (bprm->mm);

out_file:
        if (bprm->file) {
                allow_write_access(bprm->file);
                fput(bprm->file);
        }
out_kfree:
        free_bprm(bprm);

out_files:
        if (displaced)
                reset_files_struct(displaced);
out_ret:
        return retval;
}

int set_binfmt(struct linux_binfmt *new)
{
        struct linux_binfmt *old = current->binfmt;

        if (new) {
                if (!try_module_get(new->module))
                        return -1;
        }
        current->binfmt = new;
        if (old)
                module_put(old->module);
        return 0;
}

EXPORT_SYMBOL(set_binfmt);

/* format_corename will inspect the pattern parameter, and output a
 * name into corename, which must have space for at least
 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
 */
static int format_corename(char *corename, long signr)
{
        const char *pat_ptr = core_pattern;
        int ispipe = (*pat_ptr == '|');
        char *out_ptr = corename;
        char *const out_end = corename + CORENAME_MAX_SIZE;
        int rc;
        int pid_in_pattern = 0;

        /* Repeat as long as we have more pattern to process and more output
           space */
        while (*pat_ptr) {
                if (*pat_ptr != '%') {
                        if (out_ptr == out_end)
                                goto out;
                        *out_ptr++ = *pat_ptr++;
                } else {
                        switch (*++pat_ptr) {
                        case 0:
                                goto out;
                        /* Double percent, output one percent */
                        case '%':
                                if (out_ptr == out_end)
                                        goto out;
                                *out_ptr++ = '%';
                                break;
                        /* pid */
                        case 'p':
                                pid_in_pattern = 1;
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%d", task_tgid_vnr(current));
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        /* uid */
                        case 'u':
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%d", current->uid);
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        /* gid */
                        case 'g':
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%d", current->gid);
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        /* signal that caused the coredump */
                        case 's':
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%ld", signr);
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        /* UNIX time of coredump */
                        case 't': {
                                struct timeval tv;
                                do_gettimeofday(&tv);
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%lu", tv.tv_sec);
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        }
                        /* hostname */
                        case 'h':
                                down_read(&uts_sem);
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%s", utsname()->nodename);
                                up_read(&uts_sem);
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        /* executable */
                        case 'e':
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%s", current->comm);
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        /* core limit size */
                        case 'c':
                                rc = snprintf(out_ptr, out_end - out_ptr,
                                              "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
                                break;
                        default:
                                break;
                        }
                        ++pat_ptr;
                }
        }
        /* Backward compatibility with core_uses_pid:
         *
         * If core_pattern does not include a %p (as is the default)
         * and core_uses_pid is set, then .%pid will be appended to
         * the filename. Do not do this for piped commands. */
        if (!ispipe && !pid_in_pattern && core_uses_pid) {
                rc = snprintf(out_ptr, out_end - out_ptr,
                              ".%d", task_tgid_vnr(current));
                if (rc > out_end - out_ptr)
                        goto out;
                out_ptr += rc;
        }
out:
        *out_ptr = 0;
        return ispipe;
}

static int zap_process(struct task_struct *start)
{
        struct task_struct *t;
        int nr = 0;

        start->signal->flags = SIGNAL_GROUP_EXIT;
        start->signal->group_stop_count = 0;

        t = start;
        do {
                if (t != current && t->mm) {
                        sigaddset(&t->pending.signal, SIGKILL);
                        signal_wake_up(t, 1);
                        nr++;
                }
        } while_each_thread(start, t);

        return nr;
}

static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
                                struct core_state *core_state, int exit_code)
{
        struct task_struct *g, *p;
        unsigned long flags;
        int nr = -EAGAIN;

        spin_lock_irq(&tsk->sighand->siglock);
        if (!signal_group_exit(tsk->signal)) {
                mm->core_state = core_state;
                tsk->signal->group_exit_code = exit_code;
                nr = zap_process(tsk);
        }
        spin_unlock_irq(&tsk->sighand->siglock);
        if (unlikely(nr < 0))
                return nr;

        if (atomic_read(&mm->mm_users) == nr + 1)
                goto done;
        /*
         * We should find and kill all tasks which use this mm, and we should
         * count them correctly into ->nr_threads. We don't take tasklist
         * lock, but this is safe wrt:
         *
         * fork:
         *        None of sub-threads can fork after zap_process(leader). All
         *        processes which were created before this point should be
         *        visible to zap_threads() because copy_process() adds the new
         *        process to the tail of init_task.tasks list, and lock/unlock
         *        of ->siglock provides a memory barrier.
         *
         * do_exit:
         *        The caller holds mm->mmap_sem. This means that the task which
         *        uses this mm can't pass exit_mm(), so it can't exit or clear
         *        its ->mm.
         *
         * de_thread:
         *        It does list_replace_rcu(&leader->tasks, &current->tasks),
         *        we must see either old or new leader, this does not matter.
         *        However, it can change p->sighand, so lock_task_sighand(p)
         *        must be used. Since p->mm != NULL and we hold ->mmap_sem
         *        it can't fail.
         *
         *        Note also that "g" can be the old leader with ->mm == NULL
         *        and already unhashed and thus removed from ->thread_group.
         *        This is OK, __unhash_process()->list_del_rcu() does not
         *        clear the ->next pointer, we will find the new leader via
         *        next_thread().
         */
        rcu_read_lock();
        for_each_process(g) {
                if (g == tsk->group_leader)
                        continue;
                if (g->flags & PF_KTHREAD)
                        continue;
                p = g;
                do {
                        if (p->mm) {
                                if (unlikely(p->mm == mm)) {
                                        lock_task_sighand(p, &flags);
                                        nr += zap_process(p);
                                        unlock_task_sighand(p, &flags);
                                }
                                break;
                        }
                } while_each_thread(g, p);
        }
        rcu_read_unlock();
done:
        atomic_set(&core_state->nr_threads, nr);
        return nr;
}

static int coredump_wait(int exit_code, struct core_state *core_state)
{
        struct task_struct *tsk = current;
        struct mm_struct *mm = tsk->mm;
        struct completion *vfork_done;
        int core_waiters;

        init_completion(&core_state->startup);
        core_state->dumper.task = tsk;
        core_state->dumper.next = NULL;
        core_waiters = zap_threads(tsk, mm, core_state, exit_code);
        up_write(&mm->mmap_sem);

        if (unlikely(core_waiters < 0))
                goto fail;

        /*
         * Make sure nobody is waiting for us to release the VM,
         * otherwise we can deadlock when we wait on each other
         */
        vfork_done = tsk->vfork_done;
        if (vfork_done) {
                tsk->vfork_done = NULL;
                complete(vfork_done);
        }

        if (core_waiters)
                wait_for_completion(&core_state->startup);
fail:
        return core_waiters;
}

static void coredump_finish(struct mm_struct *mm)
{
        struct core_thread *curr, *next;
        struct task_struct *task;

        next = mm->core_state->dumper.next;
        while ((curr = next) != NULL) {
                next = curr->next;
                task = curr->task;
                /*
                 * see exit_mm(), curr->task must not see
                 * ->task == NULL before we read ->next.
                 */
                smp_mb();
                curr->task = NULL;
                wake_up_process(task);
        }

        mm->core_state = NULL;
}

/*
 * set_dumpable converts traditional three-value dumpable to two flags and
 * stores them into mm->flags.  It modifies lower two bits of mm->flags, but
 * these bits are not changed atomically.  So get_dumpable can observe the
 * intermediate state.  To avoid doing unexpected behavior, get get_dumpable
 * return either old dumpable or new one by paying attention to the order of
 * modifying the bits.
 *
 * dumpable |   mm->flags (binary)
 * old  new | initial interim  final
 * ---------+-----------------------
 *  0    1  |   00      01      01
 *  0    2  |   00      10(*)   11
 *  1    0  |   01      00      00
 *  1    2  |   01      11      11
 *  2    0  |   11      10(*)   00
 *  2    1  |   11      11      01
 *
 * (*) get_dumpable regards interim value of 10 as 11.
 */
void set_dumpable(struct mm_struct *mm, int value)
{
        switch (value) {
        case 0:
                clear_bit(MMF_DUMPABLE, &mm->flags);
                smp_wmb();
                clear_bit(MMF_DUMP_SECURELY, &mm->flags);
                break;
        case 1:
                set_bit(MMF_DUMPABLE, &mm->flags);
                smp_wmb();
                clear_bit(MMF_DUMP_SECURELY, &mm->flags);
                break;
        case 2:
                set_bit(MMF_DUMP_SECURELY, &mm->flags);
                smp_wmb();
                set_bit(MMF_DUMPABLE, &mm->flags);
                break;
        }
}

int get_dumpable(struct mm_struct *mm)
{
        int ret;

        ret = mm->flags & 0x3;
        return (ret >= 2) ? 2 : ret;
}

int do_coredump(long signr, int exit_code, struct pt_regs * regs)
{
        struct core_state core_state;
        char corename[CORENAME_MAX_SIZE + 1];
        struct mm_struct *mm = current->mm;
        struct linux_binfmt * binfmt;
        struct inode * inode;
        struct file * file;
        int retval = 0;
        int fsuid = current->fsuid;
        int flag = 0;
        int ispipe = 0;
        unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
        char **helper_argv = NULL;
        int helper_argc = 0;
        char *delimit;

        audit_core_dumps(signr);

        binfmt = current->binfmt;
        if (!binfmt || !binfmt->core_dump)
                goto fail;
        down_write(&mm->mmap_sem);
        /*
         * If another thread got here first, or we are not dumpable, bail out.
         */
        if (mm->core_state || !get_dumpable(mm)) {
                up_write(&mm->mmap_sem);
                goto fail;
        }

        /*
         *        We cannot trust fsuid as being the "true" uid of the
         *        process nor do we know its entire history. We only know it
         *        was tainted so we dump it as root in mode 2.
         */
        if (get_dumpable(mm) == 2) {        /* Setuid core dump mode */
                flag = O_EXCL;                /* Stop rewrite attacks */
                current->fsuid = 0;        /* Dump root private */
        }

        retval = coredump_wait(exit_code, &core_state);
        if (retval < 0)
                goto fail;

        /*
         * Clear any false indication of pending signals that might
         * be seen by the filesystem code called to write the core file.
         */
        clear_thread_flag(TIF_SIGPENDING);

        /*
         * lock_kernel() because format_corename() is controlled by sysctl, which
         * uses lock_kernel()
         */
         lock_kernel();
        ispipe = format_corename(corename, signr);
        unlock_kernel();
        /*
         * Don't bother to check the RLIMIT_CORE value if core_pattern points
         * to a pipe.  Since we're not writing directly to the filesystem
         * RLIMIT_CORE doesn't really apply, as no actual core file will be
         * created unless the pipe reader choses to write out the core file
         * at which point file size limits and permissions will be imposed
         * as it does with any other process
         */
        if ((!ispipe) && (core_limit < binfmt->min_coredump))
                goto fail_unlock;

         if (ispipe) {
                helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
                /* Terminate the string before the first option */
                delimit = strchr(corename, ' ');
                if (delimit)
                        *delimit = '\0';
                delimit = strrchr(helper_argv[0], '/');
                if (delimit)
                        delimit++;
                else
                        delimit = helper_argv[0];
                if (!strcmp(delimit, current->comm)) {
                        printk(KERN_NOTICE "Recursive core dump detected, "
                                        "aborting\n");
                        goto fail_unlock;
                }

                core_limit = RLIM_INFINITY;

                /* SIGPIPE can happen, but it's just never processed */
                 if (call_usermodehelper_pipe(corename+1, helper_argv, NULL,
                                &file)) {
                         printk(KERN_INFO "Core dump to %s pipe failed\n",
                               corename);
                         goto fail_unlock;
                 }
         } else
                 file = filp_open(corename,
                                 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
                                 0600);
        if (IS_ERR(file))
                goto fail_unlock;
        inode = file->f_path.dentry->d_inode;
        if (inode->i_nlink > 1)
                goto close_fail;        /* multiple links - don't dump */
        if (!ispipe && d_unhashed(file->f_path.dentry))
                goto close_fail;

        /* AK: actually i see no reason to not allow this for named pipes etc.,
           but keep the previous behaviour for now. */
        if (!ispipe && !S_ISREG(inode->i_mode))
                goto close_fail;
        /*
         * Dont allow local users get cute and trick others to coredump
         * into their pre-created files:
         */
        if (inode->i_uid != current->fsuid)
                goto close_fail;
        if (!file->f_op)
                goto close_fail;
        if (!file->f_op->write)
                goto close_fail;
        if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
                goto close_fail;

        retval = binfmt->core_dump(signr, regs, file, core_limit);

        if (retval)
                current->signal->group_exit_code |= 0x80;
close_fail:
        filp_close(file, NULL);
fail_unlock:
        if (helper_argv)
                argv_free(helper_argv);

        current->fsuid = fsuid;
        coredump_finish(mm);
fail:
        return retval;
}