openbsd-compat/bsd-closefrom.c

   1 /*
   2  * Copyright (c) 2004 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 #include <limits.h>
  26 #include <stdlib.h>
  27 #include <stddef.h>
  28 #ifdef HAVE_DIRENT_H
  29 # include <dirent.h>
  30 # define NAMLEN(dirent) strlen((dirent)->d_name)
  31 #else
  32 # define dirent direct
  33 # define NAMLEN(dirent) (dirent)->d_namlen
  34 # ifdef HAVE_SYS_NDIR_H
  35 #  include <sys/ndir.h>
  36 # endif
  37 # ifdef HAVE_SYS_DIR_H
  38 #  include <sys/dir.h>
  39 # endif
  40 # ifdef HAVE_NDIR_H
  41 #  include <ndir.h>
  42 # endif
  43 #endif
  44
  45 #ifndef OPEN_MAX
  46 # define OPEN_MAX       256
  47 #endif
  48
  49 #ifndef lint
  50 static const char sudorcsid[] = "$Sudo: closefrom.c,v 1.6 2004/06/01 20:51:56 millert Exp $";
  51 #endif /* lint */
  52
  53 /*
  54  * Close all file descriptors greater than or equal to lowfd.
  55  */
  56 void
  57 closefrom(int lowfd)
  58 {
  59     long fd, maxfd;
  60 #if defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
  61     char fdpath[PATH_MAX], *endp;
  62     struct dirent *dent;
  63     DIR *dirp;
  64     int len;
  65
  66     /* Check for a /proc/$$/fd directory. */
  67     len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
  68     if (len >= 0 && (u_int)len <= sizeof(fdpath) && (dirp = opendir(fdpath))) {
  69         while ((dent = readdir(dirp)) != NULL) {
  70             fd = strtol(dent->d_name, &endp, 10);
  71             if (dent->d_name != endp && *endp == '\0' &&
  72                 fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
  73                 (void) close((int) fd);
  74         }
  75         (void) closedir(dirp);
  76     } else
  77 #endif
  78     {
  79         /*
  80          * Fall back on sysconf() or getdtablesize().  We avoid checking
  81          * resource limits since it is possible to open a file descriptor
  82          * and then drop the rlimit such that it is below the open fd.
  83          */
  84 #ifdef HAVE_SYSCONF
  85         maxfd = sysconf(_SC_OPEN_MAX);
  86 #else
  87         maxfd = getdtablesize();
  88 #endif /* HAVE_SYSCONF */
  89         if (maxfd < 0)
  90             maxfd = OPEN_MAX;
  91
  92         for (fd = lowfd; fd < maxfd; fd++)
  93             (void) close((int) fd);
  94     }
  95 }
  96
  97 #endif /* HAVE_CLOSEFROM */
  98