/*

 * Copyright (c) 2004-2005 Todd C. Miller <Todd.Miller@courtesan.com>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include "includes.h"

#if !defined(HAVE_CLOSEFROM) || defined(BROKEN_CLOSEFROM)

#include <sys/types.h>

#include <unistd.h>

#include <stdio.h>

#ifdef HAVE_FCNTL_H

# include <fcntl.h>

#endif

#include <limits.h>

#include <stdlib.h>

#include <stddef.h>

#include <string.h>

#include <unistd.h>

#ifdef HAVE_DIRENT_H

# include <dirent.h>

# define NAMLEN(dirent) strlen((dirent)->d_name)

#else

# define dirent direct

# define NAMLEN(dirent) (dirent)->d_namlen

# ifdef HAVE_SYS_NDIR_H

#  include <sys/ndir.h>

# endif

# ifdef HAVE_SYS_DIR_H

#  include <sys/dir.h>

# endif

# ifdef HAVE_NDIR_H

#  include <ndir.h>

# endif

#endif

#if defined(HAVE_LIBPROC_H)

# include <libproc.h>

#endif

#ifndef OPEN_MAX

# define OPEN_MAX 256

#endif

#if 0

__unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";

#endif /* lint */

#ifndef HAVE_FCNTL_CLOSEM

/*

 * Close all file descriptors greater than or equal to lowfd.

 */

static void

closefrom_fallback(int lowfd)

{

  long fd, maxfd;

  /*

   * Fall back on sysconf() or getdtablesize().  We avoid checking

   * resource limits since it is possible to open a file descriptor

   * and then drop the rlimit such that it is below the open fd.

   */

#ifdef HAVE_SYSCONF

  maxfd = sysconf(_SC_OPEN_MAX);

#else

  maxfd = getdtablesize();

#endif /* HAVE_SYSCONF */

  if (maxfd < 0)

    maxfd = OPEN_MAX;

  for (fd = lowfd; fd < maxfd; fd++)

    (void) close((int) fd);

}

#endif /* HAVE_FCNTL_CLOSEM */

#ifdef HAVE_FCNTL_CLOSEM

void

closefrom(int lowfd)

{

    (void) fcntl(lowfd, F_CLOSEM, 0);

}

#elif defined(HAVE_LIBPROC_H) && defined(HAVE_PROC_PIDINFO)

void

closefrom(int lowfd)

{

  int i, r, sz;

  pid_t pid = getpid();

  struct proc_fdinfo *fdinfo_buf = NULL;

  sz = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, NULL, 0);

  if (sz == 0)

    return; /* no fds, really? */

  else if (sz == -1)

    goto fallback;

  if ((fdinfo_buf = malloc(sz)) == NULL)

    goto fallback;

  r = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, fdinfo_buf, sz);

  if (r < 0 || r > sz)

    goto fallback;

  for (i = 0; i < r / (int)PROC_PIDLISTFD_SIZE; i++) {

    if (fdinfo_buf[i].proc_fd >= lowfd)

      close(fdinfo_buf[i].proc_fd);

  }

  free(fdinfo_buf);

  return;

 fallback:

  free(fdinfo_buf);

  closefrom_fallback(lowfd);

  return;

}

#elif defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)

void

closefrom(int lowfd)

{

    long fd;

    char fdpath[PATH_MAX], *endp;

    struct dirent *dent;

    DIR *dirp;

    int len;

#ifdef HAVE_CLOSE_RANGE

  if (close_range(lowfd, INT_MAX, 0) == 0)

    return;

#endif

    /* Check for a /proc/$$/fd directory. */

    len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());

    if (len > 0 && (size_t)len < sizeof(fdpath) && (dirp = opendir(fdpath))) {

  while ((dent = readdir(dirp)) != NULL) {

      fd = strtol(dent->d_name, &endp, 10);

      if (dent->d_name != endp && *endp == '\0' &&

    fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))

    (void) close((int) fd);

  }

  (void) closedir(dirp);

  return;

    }

    /* /proc/$$/fd strategy failed, fall back to brute force closure */

    closefrom_fallback(lowfd);

}

#else

void

closefrom(int lowfd)

{

  closefrom_fallback(lowfd);

}

#endif /* !HAVE_FCNTL_CLOSEM */

#endif /* HAVE_CLOSEFROM */