/*
   *  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/mman.h>
  #include <linux/a.out.h>
  #include <linux/stat.h>
  #include <linux/fcntl.h>
  #include <linux/smp_lock.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/swap.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/ptrace.h>
  #include <linux/mount.h>
  #include <linux/security.h>
  #include <linux/syscalls.h>
  #include <linux/rmap.h>

  #include <linux/tsacct_kern.h>

  #include <linux/cn_proc.h>

  #include <linux/audit.h>

  
  #include <asm/uaccess.h>
  #include <asm/mmu_context.h>
  
  #ifdef CONFIG_KMOD
  #include <linux/kmod.h>
  #endif
  
  int core_uses_pid;

  char core_pattern[128] = "core";

  int suid_dumpable = 0;
  
  EXPORT_SYMBOL(suid_dumpable);

  /* The maximal length of core_pattern is also specified in sysctl.c */
  
  static struct linux_binfmt *formats;
  static DEFINE_RWLOCK(binfmt_lock);
  
  int register_binfmt(struct linux_binfmt * fmt)
  {
  	struct linux_binfmt ** tmp = &formats;
  
  	if (!fmt)
  		return -EINVAL;
  	if (fmt->next)
  		return -EBUSY;
  	write_lock(&binfmt_lock);
  	while (*tmp) {
  		if (fmt == *tmp) {
  			write_unlock(&binfmt_lock);
  			return -EBUSY;
  		}
  		tmp = &(*tmp)->next;
  	}
  	fmt->next = formats;
  	formats = fmt;
  	write_unlock(&binfmt_lock);
  	return 0;	
  }
  
  EXPORT_SYMBOL(register_binfmt);
  
  int unregister_binfmt(struct linux_binfmt * fmt)
  {
  	struct linux_binfmt ** tmp = &formats;
  
  	write_lock(&binfmt_lock);
  	while (*tmp) {
  		if (fmt == *tmp) {
  			*tmp = fmt->next;
  			write_unlock(&binfmt_lock);
  			return 0;
  		}
  		tmp = &(*tmp)->next;
  	}
  	write_unlock(&binfmt_lock);
  	return -EINVAL;
  }
  
  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;
  	int error;

  	error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);

  	if (error)
  		goto out;
  
  	error = -EINVAL;
  	if (!S_ISREG(nd.dentry->d_inode->i_mode))
  		goto exit;

  	error = vfs_permission(&nd, MAY_READ | MAY_EXEC);

  	if (error)
  		goto exit;

  	file = nameidata_to_filp(&nd, O_RDONLY);

  	error = PTR_ERR(file);
  	if (IS_ERR(file))
  		goto out;
  
  	error = -ENOEXEC;
  	if(file->f_op) {
  		struct linux_binfmt * fmt;
  
  		read_lock(&binfmt_lock);
  		for (fmt = formats ; fmt ; fmt = fmt->next) {
  			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_release(&nd);
  	goto out;
  }
  
  /*
   * 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 user
   * memory to free pages in kernel mem. These are in a format ready
   * to be put directly into the top of new user memory.
   */

  static int copy_strings(int argc, char __user * __user * argv,
  			struct linux_binprm *bprm)

  {
  	struct page *kmapped_page = NULL;
  	char *kaddr = NULL;
  	int ret;
  
  	while (argc-- > 0) {
  		char __user *str;
  		int len;
  		unsigned long pos;
  
  		if (get_user(str, argv+argc) ||
  				!(len = strnlen_user(str, bprm->p))) {
  			ret = -EFAULT;
  			goto out;
  		}
  
  		if (bprm->p < len)  {
  			ret = -E2BIG;
  			goto out;
  		}
  
  		bprm->p -= len;
  		/* XXX: add architecture specific overflow check here. */
  		pos = bprm->p;
  
  		while (len > 0) {
  			int i, new, err;
  			int offset, bytes_to_copy;
  			struct page *page;
  
  			offset = pos % PAGE_SIZE;
  			i = pos/PAGE_SIZE;
  			page = bprm->page[i];
  			new = 0;
  			if (!page) {
  				page = alloc_page(GFP_HIGHUSER);
  				bprm->page[i] = page;
  				if (!page) {
  					ret = -ENOMEM;
  					goto out;
  				}
  				new = 1;
  			}
  
  			if (page != kmapped_page) {
  				if (kmapped_page)
  					kunmap(kmapped_page);
  				kmapped_page = page;
  				kaddr = kmap(kmapped_page);
  			}
  			if (new && offset)
  				memset(kaddr, 0, offset);
  			bytes_to_copy = PAGE_SIZE - offset;
  			if (bytes_to_copy > len) {
  				bytes_to_copy = len;
  				if (new)
  					memset(kaddr+offset+len, 0,
  						PAGE_SIZE-offset-len);
  			}
  			err = copy_from_user(kaddr+offset, str, bytes_to_copy);
  			if (err) {
  				ret = -EFAULT;
  				goto out;
  			}
  
  			pos += bytes_to_copy;
  			str += bytes_to_copy;
  			len -= bytes_to_copy;
  		}
  	}
  	ret = 0;
  out:
  	if (kmapped_page)
  		kunmap(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
  /*
   * This routine is used to map in a page into an address space: needed by
   * execve() for the initial stack and environment pages.
   *
   * vma->vm_mm->mmap_sem is held for writing.
   */
  void install_arg_page(struct vm_area_struct *vma,
  			struct page *page, unsigned long address)
  {
  	struct mm_struct *mm = vma->vm_mm;

  	pte_t * pte;

  	spinlock_t *ptl;

  
  	if (unlikely(anon_vma_prepare(vma)))

  		goto out;

  
  	flush_dcache_page(page);

  	pte = get_locked_pte(mm, address, &ptl);

  	if (!pte)
  		goto out;
  	if (!pte_none(*pte)) {

  		pte_unmap_unlock(pte, ptl);

  		goto out;
  	}

  	inc_mm_counter(mm, anon_rss);

  	lru_cache_add_active(page);
  	set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
  					page, vma->vm_page_prot))));

  	page_add_new_anon_rmap(page, vma, address);

  	pte_unmap_unlock(pte, ptl);

  
  	/* no need for flush_tlb */
  	return;
  out:

  	__free_page(page);
  	force_sig(SIGKILL, current);
  }
  
  #define EXTRA_STACK_VM_PAGES	20	/* random */
  
  int setup_arg_pages(struct linux_binprm *bprm,
  		    unsigned long stack_top,
  		    int executable_stack)
  {
  	unsigned long stack_base;
  	struct vm_area_struct *mpnt;
  	struct mm_struct *mm = current->mm;
  	int i, ret;
  	long arg_size;
  
  #ifdef CONFIG_STACK_GROWSUP
  	/* Move the argument and environment strings to the bottom of the
  	 * stack space.
  	 */
  	int offset, j;
  	char *to, *from;
  
  	/* Start by shifting all the pages down */
  	i = 0;
  	for (j = 0; j < MAX_ARG_PAGES; j++) {
  		struct page *page = bprm->page[j];
  		if (!page)
  			continue;
  		bprm->page[i++] = page;
  	}
  
  	/* Now move them within their pages */
  	offset = bprm->p % PAGE_SIZE;
  	to = kmap(bprm->page[0]);
  	for (j = 1; j < i; j++) {
  		memmove(to, to + offset, PAGE_SIZE - offset);
  		from = kmap(bprm->page[j]);
  		memcpy(to + PAGE_SIZE - offset, from, offset);
  		kunmap(bprm->page[j - 1]);
  		to = from;
  	}
  	memmove(to, to + offset, PAGE_SIZE - offset);
  	kunmap(bprm->page[j - 1]);
  
  	/* Limit stack size to 1GB */
  	stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
  	if (stack_base > (1 << 30))
  		stack_base = 1 << 30;
  	stack_base = PAGE_ALIGN(stack_top - stack_base);
  
  	/* Adjust bprm->p to point to the end of the strings. */
  	bprm->p = stack_base + PAGE_SIZE * i - offset;
  
  	mm->arg_start = stack_base;
  	arg_size = i << PAGE_SHIFT;
  
  	/* zero pages that were copied above */
  	while (i < MAX_ARG_PAGES)
  		bprm->page[i++] = NULL;
  #else
  	stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
  	stack_base = PAGE_ALIGN(stack_base);
  	bprm->p += stack_base;
  	mm->arg_start = bprm->p;
  	arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
  #endif
  
  	arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
  
  	if (bprm->loader)
  		bprm->loader += stack_base;
  	bprm->exec += stack_base;

  	mpnt = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);

  	if (!mpnt)
  		return -ENOMEM;

  	memset(mpnt, 0, sizeof(*mpnt));
  
  	down_write(&mm->mmap_sem);
  	{
  		mpnt->vm_mm = mm;
  #ifdef CONFIG_STACK_GROWSUP
  		mpnt->vm_start = stack_base;
  		mpnt->vm_end = stack_base + arg_size;
  #else
  		mpnt->vm_end = stack_top;
  		mpnt->vm_start = mpnt->vm_end - arg_size;
  #endif
  		/* 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))
  			mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
  		else if (executable_stack == EXSTACK_DISABLE_X)
  			mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
  		else
  			mpnt->vm_flags = VM_STACK_FLAGS;
  		mpnt->vm_flags |= mm->def_flags;
  		mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
  		if ((ret = insert_vm_struct(mm, mpnt))) {
  			up_write(&mm->mmap_sem);
  			kmem_cache_free(vm_area_cachep, mpnt);
  			return ret;
  		}
  		mm->stack_vm = mm->total_vm = vma_pages(mpnt);
  	}
  
  	for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
  		struct page *page = bprm->page[i];
  		if (page) {
  			bprm->page[i] = NULL;
  			install_arg_page(mpnt, page, stack_base);
  		}
  		stack_base += PAGE_SIZE;
  	}
  	up_write(&mm->mmap_sem);
  	
  	return 0;
  }
  
  EXPORT_SYMBOL(setup_arg_pages);
  
  #define free_arg_pages(bprm) do { } while (0)
  
  #else
  
  static inline void free_arg_pages(struct linux_binprm *bprm)
  {
  	int i;
  
  	for (i = 0; i < MAX_ARG_PAGES; i++) {
  		if (bprm->page[i])
  			__free_page(bprm->page[i]);
  		bprm->page[i] = NULL;
  	}
  }
  
  #endif /* CONFIG_MMU */
  
  struct file *open_exec(const char *name)
  {
  	struct nameidata nd;
  	int err;
  	struct file *file;

  	err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);

  	file = ERR_PTR(err);
  
  	if (!err) {
  		struct inode *inode = nd.dentry->d_inode;
  		file = ERR_PTR(-EACCES);
  		if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
  		    S_ISREG(inode->i_mode)) {

  			int err = vfs_permission(&nd, MAY_EXEC);

  			file = ERR_PTR(err);
  			if (!err) {

  				file = nameidata_to_filp(&nd, O_RDONLY);

  				if (!IS_ERR(file)) {
  					err = deny_write_access(file);
  					if (err) {
  						fput(file);
  						file = ERR_PTR(err);
  					}
  				}
  out:
  				return file;
  			}
  		}

  		release_open_intent(&nd);

  		path_release(&nd);
  	}
  	goto out;
  }
  
  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_waiters and changing tsk->mm.  The
  		 * core-inducing thread will increment core_waiters for
  		 * each thread whose ->mm == old_mm.
  		 */
  		down_read(&old_mm->mmap_sem);
  		if (unlikely(old_mm->core_waiters)) {
  			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);

  		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 *newsighand, *oldsighand = tsk->sighand;
  	spinlock_t *lock = &oldsighand->siglock;

  	struct task_struct *leader = NULL;

  	int count;
  
  	/*
  	 * If we don't share sighandlers, then we aren't sharing anything
  	 * and we can just re-use it all.
  	 */
  	if (atomic_read(&oldsighand->count) <= 1) {
  		BUG_ON(atomic_read(&sig->count) != 1);
  		exit_itimers(sig);
  		return 0;
  	}
  
  	newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
  	if (!newsighand)
  		return -ENOMEM;

  	if (thread_group_empty(tsk))

  		goto no_thread_group;
  
  	/*
  	 * Kill all other threads in the thread group.
  	 * We must hold tasklist_lock to call zap_other_threads.
  	 */
  	read_lock(&tasklist_lock);
  	spin_lock_irq(lock);
  	if (sig->flags & SIGNAL_GROUP_EXIT) {
  		/*
  		 * Another group action in progress, just
  		 * return so that the signal is processed.
  		 */
  		spin_unlock_irq(lock);
  		read_unlock(&tasklist_lock);
  		kmem_cache_free(sighand_cachep, newsighand);
  		return -EAGAIN;
  	}

  
  	/*
  	 * child_reaper ignores SIGKILL, change it now.
  	 * Reparenting needs write_lock on tasklist_lock,
  	 * so it is safe to do it under read_lock.
  	 */

  	if (unlikely(tsk->group_leader == child_reaper(tsk)))
  		tsk->nsproxy->pid_ns->child_reaper = tsk;

  	zap_other_threads(tsk);

  	read_unlock(&tasklist_lock);
  
  	/*
  	 * Account for the thread group leader hanging around:
  	 */

  	count = 1;

  	if (!thread_group_leader(tsk)) {

  		count = 2;

  		/*
  		 * The SIGALRM timer survives the exec, but needs to point
  		 * at us as the new group leader now.  We have a race with
  		 * a timer firing now getting the old leader, so we need to
  		 * synchronize with any firing (by calling del_timer_sync)
  		 * before we can safely let the old group leader die.
  		 */

  		sig->tsk = tsk;

  		spin_unlock_irq(lock);

  		if (hrtimer_cancel(&sig->real_timer))
  			hrtimer_restart(&sig->real_timer);

  		spin_lock_irq(lock);

  	}

  	while (atomic_read(&sig->count) > count) {

  		sig->group_exit_task = tsk;

  		sig->notify_count = count;
  		__set_current_state(TASK_UNINTERRUPTIBLE);
  		spin_unlock_irq(lock);
  		schedule();
  		spin_lock_irq(lock);
  	}
  	sig->group_exit_task = NULL;
  	sig->notify_count = 0;
  	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)) {

  		/*
  		 * Wait for the thread group leader to be a zombie.
  		 * It should already be zombie at this point, most
  		 * of the time.
  		 */

  		leader = tsk->group_leader;

  		while (leader->exit_state != EXIT_ZOMBIE)
  			yield();

  		/*
  		 * 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;

  		write_lock_irq(&tasklist_lock);

  		BUG_ON(leader->tgid != tsk->tgid);
  		BUG_ON(tsk->pid == tsk->tgid);

  		/*
  		 * 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,  tsk->pid);
  		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);

          }
  
  	/*

  	 * There may be one thread left which is just exiting,
  	 * but it's safe to stop telling the group to kill themselves.

  	 */
  	sig->flags = 0;
  
  no_thread_group:

  	exit_itimers(sig);

  	if (leader)
  		release_task(leader);
  
  	BUG_ON(atomic_read(&sig->count) != 1);

  
  	if (atomic_read(&oldsighand->count) == 1) {
  		/*
  		 * Now that we nuked the rest of the thread group,
  		 * it turns out we are not sharing sighand any more either.
  		 * So we can just keep it.
  		 */
  		kmem_cache_free(sighand_cachep, newsighand);
  	} else {
  		/*
  		 * Move our state over to newsighand and switch it in.
  		 */

  		atomic_set(&newsighand->count, 1);
  		memcpy(newsighand->action, oldsighand->action,
  		       sizeof(newsighand->action));
  
  		write_lock_irq(&tasklist_lock);
  		spin_lock(&oldsighand->siglock);

  		spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);

  		rcu_assign_pointer(tsk->sighand, newsighand);

  		recalc_sigpending();
  
  		spin_unlock(&newsighand->siglock);
  		spin_unlock(&oldsighand->siglock);
  		write_unlock_irq(&tasklist_lock);
  
  		if (atomic_dec_and_test(&oldsighand->count))

  			kmem_cache_free(sighand_cachep, 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);
  }
  
  void 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);
  }
  
  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;
  	struct files_struct *files;
  	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;
  
  	/*
  	 * Make sure we have private file handles. Ask the
  	 * fork helper to do the work for us and the exit
  	 * helper to do the cleanup of the old one.
  	 */
  	files = current->files;		/* refcounted so safe to hold */
  	retval = unshare_files();
  	if (retval)
  		goto out;
  	/*
  	 * Release all of the old mmap stuff
  	 */
  	retval = exec_mmap(bprm->mm);
  	if (retval)
  		goto mmap_failed;
  
  	bprm->mm = NULL;		/* We're using it now */
  
  	/* This is the point of no return */

  	put_files_struct(files);
  
  	current->sas_ss_sp = current->sas_ss_size = 0;
  
  	if (current->euid == current->uid && current->egid == current->gid)
  		current->mm->dumpable = 1;

  	else
  		current->mm->dumpable = 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 || 

  	    file_permission(bprm->file, MAY_READ) ||

  	    (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
  		suid_keys(current);

  		current->mm->dumpable = 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;
  
  mmap_failed:

  	reset_files_struct(current, files);

  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 = 0;
  	if (p->ptrace & PT_PTRACED) {
  		if (p->ptrace & PT_PTRACE_CAP)
  			unsafe |= LSM_UNSAFE_PTRACE_CAP;
  		else
  			unsafe |= LSM_UNSAFE_PTRACE;
  	}
  	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);
  	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);
  
  void remove_arg_zero(struct linux_binprm *bprm)
  {
  	if (bprm->argc) {
  		unsigned long offset;
  		char * kaddr;
  		struct page *page;
  
  		offset = bprm->p % PAGE_SIZE;
  		goto inside;
  
  		while (bprm->p++, *(kaddr+offset++)) {
  			if (offset != PAGE_SIZE)
  				continue;
  			offset = 0;
  			kunmap_atomic(kaddr, KM_USER0);
  inside:
  			page = bprm->page[bprm->p/PAGE_SIZE];
  			kaddr = kmap_atomic(page, KM_USER0);
  		}
  		kunmap_atomic(kaddr, KM_USER0);
  		bprm->argc--;
  	}
  }
  
  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)
  {
  	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 = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
  
  		file = open_exec("/sbin/loader");
  		retval = PTR_ERR(file);
  		if (IS_ERR(file))
  			return retval;
  
  		/* Remember if the application is TASO.  */
  		bprm->sh_bang = 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);
  		for (fmt = formats ; fmt ; fmt = fmt->next) {
  			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);
  			if (retval >= 0) {
  				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_KMOD
  		}else{
  #define printable(c) (((c)=='\t') || ((c)=='
  ') || (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);
  
  /*
   * 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;
  	int retval;
  	int i;
  
  	retval = -ENOMEM;

  	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);

  	if (!bprm)
  		goto out_ret;

  
  	file = open_exec(filename);
  	retval = PTR_ERR(file);
  	if (IS_ERR(file))
  		goto out_kfree;
  
  	sched_exec();
  
  	bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
  
  	bprm->file = file;
  	bprm->filename = filename;
  	bprm->interp = filename;
  	bprm->mm = mm_alloc();
  	retval = -ENOMEM;
  	if (!bprm->mm)
  		goto out_file;
  
  	retval = init_new_context(current, bprm->mm);
  	if (retval < 0)
  		goto out_mm;
  
  	bprm->argc = count(argv, bprm->p / sizeof(void *));
  	if ((retval = bprm->argc) < 0)
  		goto out_mm;
  
  	bprm->envc = count(envp, bprm->p / sizeof(void *));
  	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;
  
  	retval = search_binary_handler(bprm,regs);
  	if (retval >= 0) {
  		free_arg_pages(bprm);
  
  		/* execve success */
  		security_bprm_free(bprm);
  		acct_update_integrals(current);

  		kfree(bprm);
  		return retval;
  	}
  
  out:
  	/* Something went wrong, return the inode and free the argument pages*/
  	for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
  		struct page * page = bprm->page[i];
  		if (page)
  			__free_page(page);
  	}
  
  	if (bprm->security)
  		security_bprm_free(bprm);
  
  out_mm:
  	if (bprm->mm)
  		mmdrop(bprm->mm);
  
  out_file:
  	if (bprm->file) {
  		allow_write_access(bprm->file);
  		fput(bprm->file);
  	}
  
  out_kfree:
  	kfree(bprm);
  
  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);
  
  #define CORENAME_MAX_SIZE 64
  
  /* 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 void format_corename(char *corename, const char *pattern, long signr)
  {
  	const char *pat_ptr = pattern;
  	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", current->tgid);
  				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;
  			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 */
  	if (!pid_in_pattern
              && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
  		rc = snprintf(out_ptr, out_end - out_ptr,
  			      ".%d", current->tgid);
  		if (rc > out_end - out_ptr)
  			goto out;
  		out_ptr += rc;
  	}
        out:
  	*out_ptr = 0;
  }

  static void zap_process(struct task_struct *start)

  {
  	struct task_struct *t;

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

  
  	t = start;
  	do {
  		if (t != current && t->mm) {
  			t->mm->core_waiters++;

  			sigaddset(&t->pending.signal, SIGKILL);
  			signal_wake_up(t, 1);

  		}
  	} while ((t = next_thread(t)) != start);
  }

  static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
  				int exit_code)

  {
  	struct task_struct *g, *p;

  	unsigned long flags;

  	int err = -EAGAIN;
  
  	spin_lock_irq(&tsk->sighand->siglock);
  	if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) {

  		tsk->signal->group_exit_code = exit_code;

  		zap_process(tsk);

  		err = 0;

  	}

  	spin_unlock_irq(&tsk->sighand->siglock);
  	if (err)
  		return err;

  	if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
  		goto done;

  	rcu_read_lock();

  	for_each_process(g) {

  		if (g == tsk->group_leader)
  			continue;

  		p = g;
  		do {
  			if (p->mm) {

  				if (p->mm == mm) {
  					/*
  					 * p->sighand can't disappear, but
  					 * may be changed by de_thread()
  					 */
  					lock_task_sighand(p, &flags);

  					zap_process(p);

  					unlock_task_sighand(p, &flags);
  				}

  				break;
  			}
  		} while ((p = next_thread(p)) != g);
  	}

  	rcu_read_unlock();

  done:

  	return mm->core_waiters;

  }

  static int coredump_wait(int exit_code)

  {

  	struct task_struct *tsk = current;
  	struct mm_struct *mm = tsk->mm;
  	struct completion startup_done;
  	struct completion *vfork_done;

  	int core_waiters;

  	init_completion(&mm->core_done);
  	init_completion(&startup_done);

  	mm->core_startup_done = &startup_done;

  	core_waiters = zap_threads(tsk, mm, 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(&startup_done);

  fail:

  	BUG_ON(mm->core_waiters);

  	return core_waiters;

  }
  
  int do_coredump(long signr, int exit_code, struct pt_regs * regs)
  {
  	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;

  
  	binfmt = current->binfmt;
  	if (!binfmt || !binfmt->core_dump)
  		goto fail;
  	down_write(&mm->mmap_sem);
  	if (!mm->dumpable) {
  		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 (mm->dumpable == 2) {	/* Setuid core dump mode */
  		flag = O_EXCL;		/* Stop rewrite attacks */
  		current->fsuid = 0;	/* Dump root private */
  	}

  	mm->dumpable = 0;

  	retval = coredump_wait(exit_code);
  	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);
  
  	if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
  		goto fail_unlock;
  
  	/*
  	 * lock_kernel() because format_corename() is controlled by sysctl, which
  	 * uses lock_kernel()
  	 */
   	lock_kernel();
  	format_corename(corename, core_pattern, signr);
  	unlock_kernel();

   	if (corename[0] == '|') {
  		/* SIGPIPE can happen, but it's just never processed */
   		if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) {
   			printk(KERN_INFO "Core dump to %s pipe failed
  ",
  			       corename);
   			goto fail_unlock;
   		}
  		ispipe = 1;
   	} 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;
  	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);
  
  	if (retval)
  		current->signal->group_exit_code |= 0x80;
  close_fail:
  	filp_close(file, NULL);
  fail_unlock:

  	current->fsuid = fsuid;

  	complete_all(&mm->core_done);
  fail:
  	return retval;
  }