compat/closefrom.c

   1 /*
   2  * Copyright (c) 2004-2005 Todd C. Miller <Todd.Miller@courtesan.com>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef HAVE_CLOSEFROM
  18
  19 #include <sys/types.h>
  20 #include <sys/param.h>
  21 #include <unistd.h>
  22 #include <stdio.h>
  23 #ifdef HAVE_FCNTL_H
  24 # include <fcntl.h>
  25 #endif
  26 #include <limits.h>
  27 #include <stdlib.h>
  28 #include <stddef.h>
  29 #include <string.h>
  30 #include <unistd.h>
  31 #ifdef HAVE_DIRENT_H
  32 # include <dirent.h>
  33 # define NAMLEN(dirent) strlen((dirent)->d_name)
  34 #else
  35 # define dirent direct
  36 # define NAMLEN(dirent) (dirent)->d_namlen
  37 # ifdef HAVE_SYS_NDIR_H
  38 #  include <sys/ndir.h>
  39 # endif
  40 # ifdef HAVE_SYS_DIR_H
  41 #  include <sys/dir.h>
  42 # endif
  43 # ifdef HAVE_NDIR_H
  44 #  include <ndir.h>
  45 # endif
  46 #endif
  47
  48 #ifndef OPEN_MAX
  49 # define OPEN_MAX       256
  50 #endif
  51
  52 #if 0
  53 __unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
  54 #endif /* lint */
  55
  56 /*
  57  * Close all file descriptors greater than or equal to lowfd.
  58  */
  59 #ifdef HAVE_FCNTL_CLOSEM
  60 void
  61 closefrom(int lowfd)
  62 {
  63     (void) fcntl(lowfd, F_CLOSEM, 0);
  64 }
  65 #else
  66 void
  67 closefrom(int lowfd)
  68 {
  69     long fd, maxfd;
  70 #if defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
  71     char fdpath[PATH_MAX], *endp;
  72     struct dirent *dent;
  73     DIR *dirp;
  74     int len;
  75
  76     /* Check for a /proc/$$/fd directory. */
  77     len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
  78     if (len > 0 && (size_t)len <= sizeof(fdpath) && (dirp = opendir(fdpath))) {
  79         while ((dent = readdir(dirp)) != NULL) {
  80             fd = strtol(dent->d_name, &endp, 10);
  81             if (dent->d_name != endp && *endp == '\0' &&
  82                 fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
  83                 (void) close((int) fd);
  84         }
  85         (void) closedir(dirp);
  86     } else
  87 #endif
  88     {
  89         /*
  90          * Fall back on sysconf() or getdtablesize().  We avoid checking
  91          * resource limits since it is possible to open a file descriptor
  92          * and then drop the rlimit such that it is below the open fd.
  93          */
  94 #ifdef HAVE_SYSCONF
  95         maxfd = sysconf(_SC_OPEN_MAX);
  96 #else
  97         maxfd = getdtablesize();
  98 #endif /* HAVE_SYSCONF */
  99         if (maxfd < 0)
 100             maxfd = OPEN_MAX;
 101
 102         for (fd = lowfd; fd < maxfd; fd++)
 103             (void) close((int) fd);
 104     }
 105 }
 106 #endif /* !HAVE_FCNTL_CLOSEM */
 107 #endif /* HAVE_CLOSEFROM */