Files
sudo/compat/closefrom.c
Todd C. Miller 98ffa51545 Add guards in compat source files. Not really needed since we only
include them in the Makefile if they are needed but should not hurt
either.
2013-04-01 10:19:26 -04:00

138 lines
3.3 KiB
C

/*
* Copyright (c) 2004-2005, 2007, 2010, 2012-2013
* 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.
*/
#include <config.h>
#ifndef HAVE_CLOSEFROM
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
# include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#include <fcntl.h>
#ifdef HAVE_PSTAT_GETPROC
# include <sys/param.h>
# include <sys/pstat.h>
#else
# 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
#endif
#include "missing.h"
#ifndef HAVE_FCNTL_CLOSEM
# ifndef HAVE_DIRFD
# define closefrom_fallback closefrom
# endif
#endif
/*
* Close all file descriptors greater than or equal to lowfd.
* This is the expensive (ballback) method.
*/
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);
}
/*
* Close all file descriptors greater than or equal to lowfd.
* We try the fast way first, falling back on the slow method.
*/
#if defined(HAVE_FCNTL_CLOSEM)
void
closefrom(int lowfd)
{
if (fcntl(lowfd, F_CLOSEM, 0) == -1)
closefrom_fallback(lowfd);
}
#elif defined(HAVE_PSTAT_GETPROC)
void
closefrom(int lowfd)
{
struct pst_status pstat;
int fd;
if (pstat_getproc(&pstat, sizeof(pstat), 0, getpid()) != -1) {
for (fd = lowfd; fd <= pstat.pst_highestfd; fd++)
(void) close(fd);
} else {
closefrom_fallback(lowfd);
}
}
#elif defined(HAVE_DIRFD)
void
closefrom(int lowfd)
{
struct dirent *dent;
DIR *dirp;
char *endp;
long fd;
/* Use /proc/self/fd directory if it exists. */
if ((dirp = opendir("/proc/self/fd")) != NULL) {
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);
} else
closefrom_fallback(lowfd);
}
#endif /* HAVE_FCNTL_CLOSEM */
#endif /* HAVE_CLOSEFROM */