Commit d7396583 authored by Howard Chu's avatar Howard Chu
Browse files

ITS#3607 add automatic BDB recovery

parent 41e084e1
/* alock.c - access lock library */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 2005 The OpenLDAP Foundation.
* Portions Copyright 2004-2005 Symas Corporation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
/* ACKNOWLEDGEMENTS:
* This work was initially developed by Matthew Backes at Symas
* Corporation for inclusion in OpenLDAP Software.
*/
#include "portable.h"
#include "alock.h"
#include <ac/stdlib.h>
#include <ac/string.h>
#include <ac/unistd.h>
#include <ac/errno.h>
#include <ac/assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
static int
alock_grab_lock ( int fd, int slot )
{
int res;
#ifdef HAVE_LOCKF
res = lseek (fd, (off_t) (ALOCK_SLOT_SIZE * slot), SEEK_SET);
if (res == -1) return -1;
res = lockf (fd, F_LOCK, (off_t) ALOCK_SLOT_SIZE);
#else
# ifdef HAVE_FCNTL
struct flock lock_info;
(void) memset ((void *) &lock_info, 0, sizeof (struct flock));
lock_info.l_type = F_WRLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = (off_t) (ALOCK_SLOT_SIZE * slot);
lock_info.l_len = (off_t) ALOCK_SLOT_SIZE;
res = fcntl (fd, F_SETLKW, &lock_info);
# else
# error libalock needs lockf or fcntl
# endif
#endif
if (res == -1) {
assert (errno != EDEADLK);
return -1;
}
return 0;
}
static int
alock_release_lock ( int fd, int slot )
{
int res;
#ifdef HAVE_LOCKF
res = lseek (fd, (off_t) (ALOCK_SLOT_SIZE * slot), SEEK_SET);
if (res == -1) return -1;
res = lockf (fd, F_ULOCK, (off_t) ALOCK_SLOT_SIZE);
if (res == -1) return -1;
#else
# ifdef HAVE_FCNTL
struct flock lock_info;
(void) memset ((void *) &lock_info, 0, sizeof (struct flock));
lock_info.l_type = F_UNLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = (off_t) (ALOCK_SLOT_SIZE * slot);
lock_info.l_len = (off_t) ALOCK_SLOT_SIZE;
res = fcntl (fd, F_SETLKW, &lock_info);
if (res == -1) return -1;
# else
# error libalock needs lockf or fcntl
# endif
#endif
return 0;
}
static int
alock_test_lock ( int fd, int slot )
{
int res;
#ifdef HAVE_LOCKF
res = lseek (fd, (off_t) (ALOCK_SLOT_SIZE * slot), SEEK_SET);
if (res == -1) return -1;
res = lockf (fd, F_TEST, (off_t) ALOCK_SLOT_SIZE);
if (res == -1) {
if (errno == EACCES) {
return ALOCK_LOCKED;
} else {
return -1;
}
}
#else
# ifdef HAVE_FCNTL
struct flock lock_info;
(void) memset ((void *) &lock_info, 0, sizeof (struct flock));
lock_info.l_type = F_WRLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = (off_t) (ALOCK_SLOT_SIZE * slot);
lock_info.l_len = (off_t) ALOCK_SLOT_SIZE;
res = fcntl (fd, F_GETLK, &lock_info);
if (res == -1) return -1;
if (lock_info.l_type != F_UNLCK) return ALOCK_LOCKED;
# else
# error libalock needs lockf or fcntl
# endif
#endif
return 0;
}
/* Read a 64bit LE value */
static unsigned long int
alock_read_iattr ( unsigned char * bufptr )
{
unsigned long int val = 0;
int count;
assert (bufptr != NULL);
bufptr += sizeof (unsigned long int);
for (count=0; count <= sizeof (unsigned long int); ++count) {
val <<= 8;
val += (unsigned long int) *bufptr--;
}
return val;
}
/* Write a 64bit LE value */
static void
alock_write_iattr ( unsigned char * bufptr,
unsigned long int val )
{
int count;
assert (bufptr != NULL);
for (count=0; count < 8; ++count) {
*bufptr++ = (unsigned char) (val & 0xff);
val >>= 8;
}
}
static int
alock_read_slot ( alock_info_t * info,
alock_slot_t * slot_data )
{
unsigned char slotbuf [ALOCK_SLOT_SIZE];
int res, size, size_total, err;
assert (info != NULL);
assert (slot_data != NULL);
assert (info->al_slot > 0);
res = lseek (info->al_fd,
(off_t) (ALOCK_SLOT_SIZE * info->al_slot),
SEEK_SET);
if (res == -1) return -1;
size_total = 0;
while (size_total < ALOCK_SLOT_SIZE) {
size = read (info->al_fd,
slotbuf + size_total,
ALOCK_SLOT_SIZE - size_total);
if (size == 0) return -1;
if (size < 0) {
err = errno;
if (err != EINTR && err != EAGAIN) return -1;
} else {
size_total += size;
}
}
if (alock_read_iattr (slotbuf) != ALOCK_MAGIC) {
return 1;
}
slot_data->al_lock = alock_read_iattr (slotbuf+8);
slot_data->al_stamp = alock_read_iattr (slotbuf+16);
slot_data->al_pid = alock_read_iattr (slotbuf+24);
if (slot_data->al_appname) free (slot_data->al_appname);
slot_data->al_appname = calloc (1, ALOCK_MAX_APPNAME);
strncpy (slot_data->al_appname, slotbuf+32, ALOCK_MAX_APPNAME-1);
(slot_data->al_appname) [ALOCK_MAX_APPNAME-1] = '\0';
return 0;
}
static int
alock_write_slot ( alock_info_t * info,
alock_slot_t * slot_data )
{
unsigned char slotbuf [ALOCK_SLOT_SIZE];
int res, size, size_total, err;
assert (info != NULL);
assert (slot_data != NULL);
assert (info->al_slot > 0);
(void) memset ((void *) slotbuf, 0, ALOCK_SLOT_SIZE);
alock_write_iattr (slotbuf, ALOCK_MAGIC);
assert (alock_read_iattr (slotbuf) == ALOCK_MAGIC);
alock_write_iattr (slotbuf+8, slot_data->al_lock);
alock_write_iattr (slotbuf+16, slot_data->al_stamp);
alock_write_iattr (slotbuf+24, slot_data->al_pid);
strncpy (slotbuf+32, slot_data->al_appname, ALOCK_MAX_APPNAME-1);
slotbuf[ALOCK_SLOT_SIZE-1] = '\0';
res = lseek (info->al_fd,
(off_t) (ALOCK_SLOT_SIZE * info->al_slot),
SEEK_SET);
if (res == -1) return -1;
size_total = 0;
while (size_total < ALOCK_SLOT_SIZE) {
size = write (info->al_fd,
slotbuf + size_total,
ALOCK_SLOT_SIZE - size_total);
if (size == 0) return -1;
if (size < 0) {
err = errno;
if (err != EINTR && err != EAGAIN) return -1;
} else {
size_total += size;
}
}
return 0;
}
static int
alock_query_slot ( alock_info_t * info )
{
int res;
alock_slot_t slot_data;
assert (info != NULL);
assert (info->al_slot > 0);
(void) memset ((void *) &slot_data, 0, sizeof (alock_slot_t));
alock_read_slot (info, &slot_data);
if (slot_data.al_lock == ALOCK_UNLOCKED) return ALOCK_UNLOCKED;
if (slot_data.al_appname != NULL) free (slot_data.al_appname);
slot_data.al_appname = NULL;
res = alock_test_lock (info->al_fd, info->al_slot);
if (res < 0) return -1;
if (res > 0) {
if (slot_data.al_lock == ALOCK_UNIQUE) {
return ALOCK_UNIQUE;
} else {
return ALOCK_LOCKED;
}
}
return ALOCK_DIRTY;
}
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;
struct timeval tv;
int res, max_slot;
int dirty_count, live_count;
assert (info != NULL);
assert (appname != NULL);
assert (envdir != NULL);
assert (locktype >= 1 && locktype <= 2);
res = gettimeofday (&tv, NULL);
if (res == -1) return ALOCK_UNSTABLE;
slot_data.al_lock = locktype;
slot_data.al_stamp = tv.tv_sec;
slot_data.al_pid = getpid();
slot_data.al_appname = calloc (1, ALOCK_MAX_APPNAME);
strncpy (slot_data.al_appname, appname, ALOCK_MAX_APPNAME-1);
slot_data.al_appname [ALOCK_MAX_APPNAME-1] = '\0';
filename = calloc (1, strlen (envdir) + strlen ("/alock") + 1);
strcpy (filename, envdir);
strcat (filename, "/alock");
info->al_fd = open (filename, O_CREAT|O_RDWR, 0666);
free (filename);
if (info->al_fd < 0) {
free (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);
free (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
res = fstat (info->al_fd, &statbuf);
if (res == -1) {
close (info->al_fd);
free (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;
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_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_UNIQUE) {
close (info->al_fd);
free (slot_data.al_appname);
return ALOCK_BUSY;
} else if (res == ALOCK_DIRTY) {
++dirty_count;
} else if (res == -1) {
close (info->al_fd);
free (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
}
}
if (dirty_count && live_count) {
close (info->al_fd);
free (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);
free (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
res = alock_write_slot (info, &slot_data);
free (slot_data.al_appname);
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) return ALOCK_RECOVER;
return ALOCK_CLEAN;
}
int
alock_scan ( alock_info_t * info )
{
struct stat statbuf;
alock_info_t scan_info;
int res, max_slot;
int dirty_count, live_count;
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;
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_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;
}
}
return ALOCK_CLEAN;
}
int
alock_close ( alock_info_t * info )
{
alock_slot_t slot_data;
int res;
(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)
free (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
slot_data.al_lock = ALOCK_UNLOCKED;
res = alock_write_slot (info, &slot_data);
if (res == -1) {
close (info->al_fd);
if (slot_data.al_appname != NULL)
free (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
if (slot_data.al_appname != NULL) {
free (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) {
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;
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_LOCKED
|| res == ALOCK_UNIQUE) {
/* recovery attempt on an active db? */
close (info->al_fd);
return ALOCK_UNSTABLE;
} else if (res == ALOCK_DIRTY) {
/* mark it clean */
res = alock_read_slot (&scan_info, &slot_data);
if (res == -1) {
close (info->al_fd);
return ALOCK_UNSTABLE;
}
slot_data.al_lock = ALOCK_UNLOCKED;
res = alock_write_slot (&scan_info, &slot_data);
if (res == -1) {
close (info->al_fd);
if (slot_data.al_appname != NULL)
free (slot_data.al_appname);
return ALOCK_UNSTABLE;
}
if (slot_data.al_appname != NULL) {
free (slot_data.al_appname);
slot_data.al_appname = NULL;
}
} 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;
}
return ALOCK_CLEAN;
}
/* alock.h - access lock header */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 2005 The OpenLDAP Foundation.
* Portions Copyright 2004-2005 Symas Corporation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
/* ACKNOWLEDGEMENTS: