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#include "system.h"
#include <errno.h>
#include <rpm/rpmlog.h>
#include <rpm/rpmfileutil.h>
#include "lib/rpmlock.h"
#include "debug.h"
/* Internal interface */
enum {
RPMLOCK_READ = 1 << 0,
RPMLOCK_WRITE = 1 << 1,
RPMLOCK_WAIT = 1 << 2,
};
struct rpmlock_s {
int fd;
int openmode;
};
static rpmlock rpmlock_new(const char *lock_path)
{
rpmlock lock = (rpmlock) malloc(sizeof(*lock));
if (lock != NULL) {
mode_t oldmask = umask(022);
lock->fd = open(lock_path, O_RDWR|O_CREAT, 0644);
(void) umask(oldmask);
if (lock->fd == -1) {
lock->fd = open(lock_path, O_RDONLY);
if (lock->fd == -1) {
free(lock);
lock = NULL;
} else {
lock->openmode = RPMLOCK_READ;
}
} else {
lock->openmode = RPMLOCK_WRITE | RPMLOCK_READ;
}
}
return lock;
}
static void rpmlock_free(rpmlock lock)
{
if (lock) {
(void) close(lock->fd);
free(lock);
}
}
static int rpmlock_acquire(rpmlock lock, int mode)
{
int res = 0;
if (lock && (mode & lock->openmode)) {
struct flock info;
int cmd;
if (mode & RPMLOCK_WAIT)
cmd = F_SETLKW;
else
cmd = F_SETLK;
if (mode & RPMLOCK_READ)
info.l_type = F_RDLCK;
else
info.l_type = F_WRLCK;
info.l_whence = SEEK_SET;
info.l_start = 0;
info.l_len = 0;
info.l_pid = 0;
if (fcntl(lock->fd, cmd, &info) != -1)
res = 1;
}
return res;
}
static void rpmlock_release(rpmlock lock)
{
if (lock) {
struct flock info;
info.l_type = F_UNLCK;
info.l_whence = SEEK_SET;
info.l_start = 0;
info.l_len = 0;
info.l_pid = 0;
(void) fcntl(lock->fd, F_SETLK, &info);
}
}
/* External interface */
rpmlock rpmlockAcquire(const char *lock_path, const char *descr)
{
rpmlock lock = rpmlock_new(lock_path);
if (!lock) {
rpmlog(RPMLOG_ERR, _("can't create %s lock on %s (%s)\n"),
descr, lock_path, strerror(errno));
} else if (!rpmlock_acquire(lock, RPMLOCK_WRITE)) {
if (lock->openmode & RPMLOCK_WRITE)
rpmlog(RPMLOG_WARNING, _("waiting for %s lock on %s\n"),
descr, lock_path);
if (!rpmlock_acquire(lock, RPMLOCK_WRITE|RPMLOCK_WAIT)) {
rpmlog(RPMLOG_ERR, _("can't create %s lock on %s (%s)\n"),
descr, lock_path, strerror(errno));
rpmlock_free(lock);
lock = NULL;
}
}
return lock;
}
rpmlock rpmlockFree(rpmlock lock)
{
rpmlock_release(lock); /* Not really needed here. */
rpmlock_free(lock);
return NULL;
}
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