bsd-closefrom.c revision 137015 
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
49RCSID("$Id: bsd-closefrom.c,v 1.1 2004/08/15 08:41:00 djm Exp $");
50
51#ifndef lint
52static const char sudorcsid[] = "$Sudo: closefrom.c,v 1.6 2004/06/01 20:51:56 millert Exp $";
53#endif /* lint */
54
55/*
56 * Close all file descriptors greater than or equal to lowfd.
57 */
58void
59closefrom(int lowfd)
60{
61    long fd, maxfd;
62#if defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
63    char fdpath[PATH_MAX], *endp;
64    struct dirent *dent;
65    DIR *dirp;
66    int len;
67
68    /* Check for a /proc/$$/fd directory. */
69    len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
70    if (len != -1 && len <= sizeof(fdpath) && (dirp = opendir(fdpath))) {
71	while ((dent = readdir(dirp)) != NULL) {
72	    fd = strtol(dent->d_name, &endp, 10);
73	    if (dent->d_name != endp && *endp == '\0' &&
74		fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
75		(void) close((int) fd);
76	}
77	(void) closedir(dirp);
78    } else
79#endif
80    {
81	/*
82	 * Fall back on sysconf() or getdtablesize().  We avoid checking
83	 * resource limits since it is possible to open a file descriptor
84	 * and then drop the rlimit such that it is below the open fd.
85	 */
86#ifdef HAVE_SYSCONF
87	maxfd = sysconf(_SC_OPEN_MAX);
88#else
89	maxfd = getdtablesize();
90#endif /* HAVE_SYSCONF */
91	if (maxfd < 0)
92	    maxfd = OPEN_MAX;
93
94	for (fd = lowfd; fd < maxfd; fd++)
95	    (void) close((int) fd);
96    }
97}
98
99#endif /* HAVE_CLOSEFROM */
100
101