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#include <ccan/tdb2/tdb2.h>
#include <ccan/tap/tap.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <limits.h>
#include <errno.h>
#include "logging.h"
#include "external-agent.h"
#undef alarm
#define alarm fast_alarm
/* Speed things up by doing things in milliseconds. */
static unsigned int fast_alarm(unsigned int milli_seconds)
{
struct itimerval it;
it.it_interval.tv_sec = it.it_interval.tv_usec = 0;
it.it_value.tv_sec = milli_seconds / 1000;
it.it_value.tv_usec = milli_seconds * 1000;
setitimer(ITIMER_REAL, &it, NULL);
return 0;
}
#define CatchSignal(sig, handler) signal((sig), (handler))
static void do_nothing(int signum)
{
}
/* This example code is taken from SAMBA, so try not to change it. */
static struct flock flock_struct;
/* Return a value which is none of v1, v2 or v3. */
static inline short int invalid_value(short int v1, short int v2, short int v3)
{
short int try = (v1+v2+v3)^((v1+v2+v3) << 16);
while (try == v1 || try == v2 || try == v3)
try++;
return try;
}
/* We invalidate in as many ways as we can, so the OS rejects it */
static void invalidate_flock_struct(int signum)
{
flock_struct.l_type = invalid_value(F_RDLCK, F_WRLCK, F_UNLCK);
flock_struct.l_whence = invalid_value(SEEK_SET, SEEK_CUR, SEEK_END);
flock_struct.l_start = -1;
/* A large negative. */
flock_struct.l_len = (((off_t)1 << (sizeof(off_t)*CHAR_BIT - 1)) + 1);
}
static int timeout_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
void *_timeout)
{
int ret, saved_errno = errno;
unsigned int timeout = *(unsigned int *)_timeout;
flock_struct.l_type = rw;
flock_struct.l_whence = SEEK_SET;
flock_struct.l_start = off;
flock_struct.l_len = len;
CatchSignal(SIGALRM, invalidate_flock_struct);
alarm(timeout);
for (;;) {
if (waitflag)
ret = fcntl(fd, F_SETLKW, &flock_struct);
else
ret = fcntl(fd, F_SETLK, &flock_struct);
if (ret == 0)
break;
/* Not signalled? Something else went wrong. */
if (flock_struct.l_len == len) {
if (errno == EAGAIN || errno == EINTR)
continue;
saved_errno = errno;
break;
} else {
saved_errno = EINTR;
break;
}
}
alarm(0);
errno = saved_errno;
return ret;
}
static int tdb_chainlock_with_timeout_internal(struct tdb_context *tdb,
TDB_DATA key,
unsigned int timeout,
int rw_type)
{
union tdb_attribute locking;
enum TDB_ERROR ecode;
if (timeout) {
locking.base.attr = TDB_ATTRIBUTE_FLOCK;
ecode = tdb_get_attribute(tdb, &locking);
if (ecode != TDB_SUCCESS)
return ecode;
/* Replace locking function with our own. */
locking.flock.data = &timeout;
locking.flock.lock = timeout_lock;
ecode = tdb_set_attribute(tdb, &locking);
if (ecode != TDB_SUCCESS)
return ecode;
}
if (rw_type == F_RDLCK)
ecode = tdb_chainlock_read(tdb, key);
else
ecode = tdb_chainlock(tdb, key);
if (timeout) {
tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
}
return ecode;
}
int main(int argc, char *argv[])
{
unsigned int i;
struct tdb_context *tdb;
TDB_DATA key = tdb_mkdata("hello", 5);
int flags[] = { TDB_DEFAULT, TDB_NOMMAP,
TDB_CONVERT, TDB_NOMMAP|TDB_CONVERT,
TDB_VERSION1, TDB_NOMMAP|TDB_VERSION1,
TDB_CONVERT|TDB_VERSION1,
TDB_NOMMAP|TDB_CONVERT|TDB_VERSION1 };
struct agent *agent;
plan_tests(sizeof(flags) / sizeof(flags[0]) * 15);
agent = prepare_external_agent();
for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
enum TDB_ERROR ecode;
tdb = tdb_open("run-locktimeout.tdb", flags[i],
O_RDWR|O_CREAT|O_TRUNC, 0600, &tap_log_attr);
if (!ok1(tdb))
break;
/* Simple cases: should succeed. */
ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
F_RDLCK);
ok1(ecode == TDB_SUCCESS);
ok1(tap_log_messages == 0);
tdb_chainunlock_read(tdb, key);
ok1(tap_log_messages == 0);
ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
F_WRLCK);
ok1(ecode == TDB_SUCCESS);
ok1(tap_log_messages == 0);
tdb_chainunlock(tdb, key);
ok1(tap_log_messages == 0);
/* OK, get agent to start transaction, then we should time out. */
ok1(external_agent_operation(agent, OPEN, "run-locktimeout.tdb")
== SUCCESS);
ok1(external_agent_operation(agent, TRANSACTION_START, "")
== SUCCESS);
ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
F_WRLCK);
ok1(ecode == TDB_ERR_LOCK);
ok1(tap_log_messages == 0);
/* Even if we get a different signal, should be fine. */
CatchSignal(SIGUSR1, do_nothing);
external_agent_operation(agent, SEND_SIGNAL, "");
ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
F_WRLCK);
ok1(ecode == TDB_ERR_LOCK);
ok1(tap_log_messages == 0);
ok1(external_agent_operation(agent, TRANSACTION_COMMIT, "")
== SUCCESS);
ok1(external_agent_operation(agent, CLOSE, "")
== SUCCESS);
tdb_close(tdb);
}
free_external_agent(agent);
return exit_status();
}
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