openbsd-compat/bsd-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 #include "includes.h"
  18
  19 #ifndef HAVE_CLOSEFROM
  20
  21 #include <sys/types.h>
  22 #include <sys/param.h>
  23 #include <unistd.h>
  24 #include <stdio.h>
  25 #ifdef HAVE_FCNTL_H
  26 # include <fcntl.h>
  27 #endif
  28 #include <limits.h>
  29 #include <stdlib.h>
  30 #include <stddef.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #ifdef HAVE_DIRENT_H
  34 # include <dirent.h>
  35 # define NAMLEN(dirent) strlen((dirent)->d_name)
  36 #else
  37 # define dirent direct
  38 # define NAMLEN(dirent) (dirent)->d_namlen
  39 # ifdef HAVE_SYS_NDIR_H
  40 #  include <sys/ndir.h>
  41 # endif
  42 # ifdef HAVE_SYS_DIR_H
  43 #  include <sys/dir.h>
  44 # endif
  45 # ifdef HAVE_NDIR_H
  46 #  include <ndir.h>
  47 # endif
  48 #endif
  49
  50 #ifndef OPEN_MAX
  51 # define OPEN_MAX       256
  52 #endif
  53
  54 #if 0
  55 __unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
  56 #endif /* lint */
  57
  58 /*
  59  * Close all file descriptors greater than or equal to lowfd.
  60  */
  61 #ifdef HAVE_FCNTL_CLOSEM
  62 void
  63 closefrom(int lowfd)
  64 {
  65     (void) fcntl(lowfd, F_CLOSEM, 0);
  66 }
  67 #else
  68 void
  69 closefrom(int lowfd)
  70 {
  71     long fd, maxfd;
  72 #if defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
  73     char fdpath[PATH_MAX], *endp;
  74     struct dirent *dent;
  75     DIR *dirp;
  76     int len;
  77
  78     /* Check for a /proc/$$/fd directory. */
  79     len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
  80     if (len > 0 && (size_t)len <= sizeof(fdpath) && (dirp = opendir(fdpath))) {
  81         while ((dent = readdir(dirp)) != NULL) {
  82             fd = strtol(dent->d_name, &endp, 10);
  83             if (dent->d_name != endp && *endp == '\0' &&
  84                 fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
  85                 (void) close((int) fd);
  86         }
  87         (void) closedir(dirp);
  88     } else
  89 #endif
  90     {
  91         /*
  92          * Fall back on sysconf() or getdtablesize().  We avoid checking
  93          * resource limits since it is possible to open a file descriptor
  94          * and then drop the rlimit such that it is below the open fd.
  95          */
  96 #ifdef HAVE_SYSCONF
  97         maxfd = sysconf(_SC_OPEN_MAX);
  98 #else
  99         maxfd = getdtablesize();
 100 #endif /* HAVE_SYSCONF */
 101         if (maxfd < 0)
 102             maxfd = OPEN_MAX;
 103
 104         for (fd = lowfd; fd < maxfd; fd++)
 105             (void) close((int) fd);
 106     }
 107 }
 108 #endif /* !HAVE_FCNTL_CLOSEM */
 109 #endif /* HAVE_CLOSEFROM */