xbps/bin/xbps-rindex/sem.c
2014-04-20 10:02:54 +02:00

82 lines
2.4 KiB
C

/*-
* Copyright (c) 2014 Juan Romero Pardines.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "defs.h"
struct idxlock *
index_lock(struct xbps_handle *xhp)
{
struct idxlock *il;
mode_t myumask;
if ((il = malloc(sizeof(struct idxlock))) == NULL)
return NULL;
/*
* Generate semaphore name for target architecture.
*/
il->semname = xbps_xasprintf("/xbps-rindex-%s",
xhp->target_arch ? xhp->target_arch : xhp->native_arch);
/*
* Create/open the POSIX named semaphore.
*/
myumask = umask(0);
il->sem = sem_open(il->semname, O_CREAT, 0660, 1);
umask(myumask);
if (il->sem == SEM_FAILED) {
fprintf(stderr, "%s: failed to create/open named "
"semaphore: %s\n", _XBPS_RINDEX, strerror(errno));
free(il);
return NULL;
}
if (sem_wait(il->sem) == -1) {
fprintf(stderr, "%s: failed to lock named semaphore: %s\n",
_XBPS_RINDEX, strerror(errno));
free(il);
return NULL;
}
return il;
}
void
index_unlock(struct idxlock *il)
{
/* Unlock semaphore, close and destroy it (if possible) */
sem_post(il->sem);
sem_close(il->sem);
sem_unlink(il->semname);
free(il->semname);
free(il);
}