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
62void
63closefrom(int lowfd)
64{
65    (void) fcntl(lowfd, F_CLOSEM, 0);
66}
67#else
68void
69closefrom(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 */
110