int
alock_close ( alock_info_t * info, int nosave )
{
alock_slot_t slot_data;
int res;
if ( !info->al_slot )
return ALOCK_CLEAN;
(void) memset ((void *) &slot_data, 0, sizeof(alock_slot_t));
res = alock_grab_lock (info->al_fd, 0);
if (res == -1) {
fail:
/* Windows doesn't clean up locks immediately when a process exits.
* Make sure we release our locks, to prevent stale locks from
* hanging around.
*/
alock_release_lock (info->al_fd, 0);
close (info->al_fd);
return ALOCK_UNSTABLE;
}
/* mark our slot as clean */
res = alock_read_slot (info, &slot_data);
if (res == -1) {
if (slot_data.al_appname != NULL)
ber_memfree (slot_data.al_appname);
goto fail;
}
slot_data.al_lock = ALOCK_UNLOCKED;
if ( nosave )
slot_data.al_lock |= ALOCK_NOSAVE;
/* since we have slot 0 locked, we don't need our slot lock */
res = alock_release_lock (info->al_fd, info->al_slot);
if (res == -1) {
goto fail;
}
res = alock_write_slot (info, &slot_data);
if (res == -1) {
if (slot_data.al_appname != NULL)
ber_memfree (slot_data.al_appname);
goto fail;
}
if (slot_data.al_appname != NULL) {
ber_memfree (slot_data.al_appname);
slot_data.al_appname = NULL;
}
res = alock_release_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
res = close (info->al_fd);
if (res == -1) return ALOCK_UNSTABLE;
return ALOCK_CLEAN;
}
int
alock_close ( alock_info_t * info, int nosave )
{
alock_slot_t slot_data;
int res;
if ( !info->al_slot )
return ALOCK_CLEAN;
(void) memset ((void *) &slot_data, 0, sizeof(alock_slot_t));
res = alock_grab_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
/* mark our slot as clean */
res = alock_read_slot (info, &slot_data);
if (res == -1) {
close (info->al_fd);
if (slot_data.al_appname != NULL)
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
slot_data.al_lock = ALOCK_UNLOCKED;
if ( nosave )
slot_data.al_lock |= ALOCK_NOSAVE;
res = alock_write_slot (info, &slot_data);
if (res == -1) {
close (info->al_fd);
if (slot_data.al_appname != NULL)
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
if (slot_data.al_appname != NULL) {
ber_memfree (slot_data.al_appname);
slot_data.al_appname = NULL;
}
res = alock_release_lock (info->al_fd, info->al_slot);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
res = alock_release_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
res = close (info->al_fd);
if (res == -1) return ALOCK_UNSTABLE;
return ALOCK_CLEAN;
}
int
alock_recover ( alock_info_t * info )
{
struct stat statbuf;
alock_slot_t slot_data;
alock_info_t scan_info;
int res, max_slot;
assert (info != NULL);
scan_info.al_fd = info->al_fd;
(void) memset ((void *) &slot_data, 0, sizeof(alock_slot_t));
res = alock_grab_lock (info->al_fd, 0);
if (res == -1) {
goto fail;
}
res = fstat (info->al_fd, &statbuf);
if (res == -1) {
goto fail;
}
max_slot = (statbuf.st_size + ALOCK_SLOT_SIZE - 1) / ALOCK_SLOT_SIZE;
for (scan_info.al_slot = 1;
scan_info.al_slot < max_slot;
++ scan_info.al_slot) {
if (scan_info.al_slot != info->al_slot) {
res = alock_query_slot (&scan_info) & ~ALOCK_NOSAVE;
if (res == ALOCK_LOCKED
|| res == ALOCK_UNIQUE) {
/* recovery attempt on an active db? */
goto fail;
} else if (res == ALOCK_DIRTY) {
/* mark it clean */
res = alock_read_slot (&scan_info, &slot_data);
if (res == -1) {
goto fail;
}
slot_data.al_lock = ALOCK_UNLOCKED;
res = alock_write_slot (&scan_info, &slot_data);
if (res == -1) {
if (slot_data.al_appname != NULL)
ber_memfree (slot_data.al_appname);
goto fail;
}
if (slot_data.al_appname != NULL) {
ber_memfree (slot_data.al_appname);
slot_data.al_appname = NULL;
}
} else if (res == -1) {
goto fail;
}
}
}
res = alock_release_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
return ALOCK_CLEAN;
fail:
alock_release_lock (info->al_fd, 0);
close (info->al_fd);
return ALOCK_UNSTABLE;
}
int
alock_scan ( alock_info_t * info )
{
struct stat statbuf;
alock_info_t scan_info;
int res, max_slot;
int dirty_count, live_count, nosave;
assert (info != NULL);
scan_info.al_fd = info->al_fd;
res = alock_grab_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
res = fstat (info->al_fd, &statbuf);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
max_slot = (statbuf.st_size + ALOCK_SLOT_SIZE - 1) / ALOCK_SLOT_SIZE;
dirty_count = 0;
live_count = 0;
nosave = 0;
for (scan_info.al_slot = 1;
scan_info.al_slot < max_slot;
++ scan_info.al_slot) {
if (scan_info.al_slot != info->al_slot) {
res = alock_query_slot (&scan_info);
if (res & ALOCK_NOSAVE) {
nosave = ALOCK_NOSAVE;
res ^= ALOCK_NOSAVE;
}
if (res == ALOCK_LOCKED) {
++live_count;
} else if (res == ALOCK_DIRTY) {
++dirty_count;
} else if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
}
}
res = alock_release_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
if (dirty_count) {
if (live_count) {
close (info->al_fd);
return ALOCK_UNSTABLE;
} else {
return ALOCK_RECOVER | nosave;
}
}
return ALOCK_CLEAN | nosave;
}
int
alock_open ( alock_info_t * info,
const char * appname,
const char * envdir,
int locktype )
{
struct stat statbuf;
alock_info_t scan_info;
alock_slot_t slot_data;
char * filename;
int res, max_slot;
int dirty_count, live_count, nosave;
char *ptr;
assert (info != NULL);
assert (appname != NULL);
assert (envdir != NULL);
assert ((locktype & ALOCK_SMASK) >= 1 && (locktype & ALOCK_SMASK) <= 2);
slot_data.al_lock = locktype;
slot_data.al_stamp = time(NULL);
slot_data.al_pid = getpid();
slot_data.al_appname = ber_memcalloc (1, ALOCK_MAX_APPNAME);
if (slot_data.al_appname == NULL) {
return ALOCK_UNSTABLE;
}
strncpy (slot_data.al_appname, appname, ALOCK_MAX_APPNAME-1);
slot_data.al_appname [ALOCK_MAX_APPNAME-1] = '\0';
filename = ber_memcalloc (1, strlen (envdir) + strlen ("/alock") + 1);
if (filename == NULL ) {
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
ptr = lutil_strcopy(filename, envdir);
lutil_strcopy(ptr, "/alock");
#ifdef _WIN32
{ HANDLE handle = CreateFile (filename, GENERIC_READ|GENERIC_WRITE,
FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL, NULL);
info->al_fd = _open_osfhandle (handle, 0);
}
#else
info->al_fd = open (filename, O_CREAT|O_RDWR, 0666);
#endif
ber_memfree (filename);
if (info->al_fd < 0) {
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
info->al_slot = 0;
res = alock_grab_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
res = fstat (info->al_fd, &statbuf);
if (res == -1) {
close (info->al_fd);
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
max_slot = (statbuf.st_size + ALOCK_SLOT_SIZE - 1) / ALOCK_SLOT_SIZE;
dirty_count = 0;
live_count = 0;
nosave = 0;
scan_info.al_fd = info->al_fd;
for (scan_info.al_slot = 1;
scan_info.al_slot < max_slot;
++ scan_info.al_slot) {
if (scan_info.al_slot != info->al_slot) {
res = alock_query_slot (&scan_info);
if (res & ALOCK_NOSAVE) {
nosave = ALOCK_NOSAVE;
res ^= ALOCK_NOSAVE;
}
if (res == ALOCK_UNLOCKED
&& info->al_slot == 0) {
info->al_slot = scan_info.al_slot;
} else if (res == ALOCK_LOCKED) {
++live_count;
} else if (res == ALOCK_UNIQUE
&& (( locktype & ALOCK_SMASK ) == ALOCK_UNIQUE
|| nosave )) {
close (info->al_fd);
ber_memfree (slot_data.al_appname);
return ALOCK_BUSY;
} else if (res == ALOCK_DIRTY) {
++dirty_count;
} else if (res == -1) {
close (info->al_fd);
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
}
}
if (dirty_count && live_count) {
close (info->al_fd);
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
if (info->al_slot == 0) info->al_slot = max_slot + 1;
res = alock_grab_lock (info->al_fd,
info->al_slot);
if (res == -1) {
close (info->al_fd);
ber_memfree (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
res = alock_write_slot (info, &slot_data);
ber_memfree (slot_data.al_appname);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
alock_share_lock (info->al_fd, info->al_slot);
res = alock_release_lock (info->al_fd, 0);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
if (dirty_count) return ALOCK_RECOVER | nosave;
return ALOCK_CLEAN | nosave;
}
