Files
sudo/lib/util/locking.c
Todd C. Miller 00142c91fa Lock individual records in the timestamp file instead of the entire
file.  This will make it possible for multiple sudo processes using
the same tty to serialize their timestamp lookups.
2015-09-07 06:06:08 -06:00

100 lines
2.4 KiB
C

/*
* Copyright (c) 1999-2005, 2007, 2009-2015
* 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.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
#include <config.h>
#include <sys/types.h>
#include <stdlib.h>
#ifdef HAVE_STRING_H
# include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRING_H */
#include <ctype.h>
#include <unistd.h>
#include <fcntl.h>
#ifdef HAVE_STDBOOL_H
# include <stdbool.h>
#else
# include "compat/stdbool.h"
#endif
#include "sudo_compat.h"
#include "sudo_util.h"
#include "sudo_debug.h"
/*
* Lock/unlock all or part of a file.
*/
#ifdef HAVE_LOCKF
bool
sudo_lock_file_v1(int fd, int type)
{
return sudo_lock_region_v1(fd, type, 0);
}
bool
sudo_lock_region_v1(int fd, int type, off_t len)
{
int op;
debug_decl(sudo_lock_region, SUDO_DEBUG_UTIL)
switch (type) {
case SUDO_LOCK:
op = F_LOCK;
break;
case SUDO_TLOCK:
op = F_TLOCK;
break;
case SUDO_UNLOCK:
op = F_ULOCK;
break;
default:
debug_return_bool(false);
}
debug_return_bool(lockf(fd, op, len) == 0);
}
#else
bool
sudo_lock_file_v1(int fd, int type)
{
return sudo_lock_region_v1(fd, type, 0);
}
bool
sudo_lock_region_v1(int fd, int type, off_t len)
{
int func;
struct flock lock;
debug_decl(sudo_lock_file, SUDO_DEBUG_UTIL)
lock.l_start = 0;
lock.l_len = len;
lock.l_pid = 0;
lock.l_type = (type == SUDO_UNLOCK) ? F_UNLCK : F_WRLCK;
lock.l_whence = len ? SEEK_CUR : SEEK_SET;
func = (type == SUDO_LOCK) ? F_SETLKW : F_SETLK;
debug_return_bool(fcntl(fd, func, &lock) == 0);
}
#endif