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