summaryrefslogtreecommitdiffstats
path: root/compat/closefrom.c
blob: be0082398f7ba3baa74062cb5a6f76f29420f6b0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
/*
 * Copyright (c) 2004-2005 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef HAVE_CLOSEFROM

#include <sys/types.h>
#include <sys/param.h>
#include <unistd.h>
#include <stdio.h>
#ifdef HAVE_FCNTL_H
# include <fcntl.h>
#endif
#include <limits.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>
#ifdef HAVE_DIRENT_H
# include <dirent.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#else
# define dirent direct
# define NAMLEN(dirent) (dirent)->d_namlen
# ifdef HAVE_SYS_NDIR_H
#  include <sys/ndir.h>
# endif
# ifdef HAVE_SYS_DIR_H
#  include <sys/dir.h>
# endif
# ifdef HAVE_NDIR_H
#  include <ndir.h>
# endif
#endif
#if defined(HAVE_LIBPROC_H)
# include <libproc.h>
#endif

#include "compat.h"

#ifndef OPEN_MAX
# define OPEN_MAX	256
#endif

#if 0
__unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
#endif /* lint */

#ifndef HAVE_FCNTL_CLOSEM
/*
 * Close all file descriptors greater than or equal to lowfd.
 */
static void
closefrom_fallback(int lowfd)
{
	long fd, maxfd;

	/*
	 * Fall back on sysconf() or getdtablesize().  We avoid checking
	 * resource limits since it is possible to open a file descriptor
	 * and then drop the rlimit such that it is below the open fd.
	 */
#ifdef HAVE_SYSCONF
	maxfd = sysconf(_SC_OPEN_MAX);
#else
	maxfd = getdtablesize();
#endif /* HAVE_SYSCONF */
	if (maxfd < 0)
		maxfd = OPEN_MAX;

	for (fd = lowfd; fd < maxfd; fd++)
		(void) close((int) fd);
}
#endif /* HAVE_FCNTL_CLOSEM */

#ifdef HAVE_FCNTL_CLOSEM
void
closefrom(int lowfd)
{
    (void) fcntl(lowfd, F_CLOSEM, 0);
}
#elif defined(HAVE_LIBPROC_H) && defined(HAVE_PROC_PIDINFO)
void
closefrom(int lowfd)
{
	int i, r, sz;
	pid_t pid = getpid();
	struct proc_fdinfo *fdinfo_buf = NULL;

	sz = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, NULL, 0);
	if (sz == 0)
		return; /* no fds, really? */
	else if (sz == -1)
		goto fallback;
	if ((fdinfo_buf = malloc(sz)) == NULL)
		goto fallback;
	r = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, fdinfo_buf, sz);
	if (r < 0 || r > sz)
		goto fallback;
	for (i = 0; i < r / (int)PROC_PIDLISTFD_SIZE; i++) {
		if (fdinfo_buf[i].proc_fd >= lowfd)
			close(fdinfo_buf[i].proc_fd);
	}
	free(fdinfo_buf);
	return;
 fallback:
	free(fdinfo_buf);
	closefrom_fallback(lowfd);
	return;
}
#elif defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
void
closefrom(int lowfd)
{
    long fd;
    char fdpath[PATH_MAX], *endp;
    struct dirent *dent;
    DIR *dirp;
    int len;

    /* Check for a /proc/$$/fd directory. */
    len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
    if (len > 0 && (size_t)len < sizeof(fdpath) && (dirp = opendir(fdpath))) {
	while ((dent = readdir(dirp)) != NULL) {
	    fd = strtol(dent->d_name, &endp, 10);
	    if (dent->d_name != endp && *endp == '\0' &&
		fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
		(void) close((int) fd);
	}
	(void) closedir(dirp);
	return;
    }
    /* /proc/$$/fd strategy failed, fall back to brute force closure */
    closefrom_fallback(lowfd);
}
#else
void
closefrom(int lowfd)
{
	closefrom_fallback(lowfd);
}
#endif /* !HAVE_FCNTL_CLOSEM */
#endif /* HAVE_CLOSEFROM */