summaryrefslogtreecommitdiff
path: root/source3/locking/brlock.c
diff options
context:
space:
mode:
Diffstat (limited to 'source3/locking/brlock.c')
-rw-r--r--source3/locking/brlock.c610
1 files changed, 610 insertions, 0 deletions
diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
new file mode 100644
index 0000000000..e7fa4022f6
--- /dev/null
+++ b/source3/locking/brlock.c
@@ -0,0 +1,610 @@
+/*
+ Unix SMB/CIFS implementation.
+ byte range locking code
+ Updated to handle range splits/merges.
+
+ Copyright (C) Andrew Tridgell 1992-2000
+ Copyright (C) Jeremy Allison 1992-2000
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/* This module implements a tdb based byte range locking service,
+ replacing the fcntl() based byte range locking previously
+ used. This allows us to provide the same semantics as NT */
+
+#include "includes.h"
+
+#define ZERO_ZERO 0
+
+/* This contains elements that differentiate locks. The smbpid is a
+ client supplied pid, and is essentially the locking context for
+ this client */
+
+struct lock_context {
+ uint16 smbpid;
+ uint16 tid;
+ pid_t pid;
+};
+
+/* The data in brlock records is an unsorted linear array of these
+ records. It is unnecessary to store the count as tdb provides the
+ size of the record */
+
+struct lock_struct {
+ struct lock_context context;
+ br_off start;
+ br_off size;
+ int fnum;
+ enum brl_type lock_type;
+};
+
+/* The key used in the brlock database. */
+
+struct lock_key {
+ SMB_DEV_T device;
+ SMB_INO_T inode;
+};
+
+/* The open brlock.tdb database. */
+
+static TDB_CONTEXT *tdb;
+
+/****************************************************************************
+ Create a locking key - ensuring zero filled for pad purposes.
+****************************************************************************/
+
+static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
+{
+ static struct lock_key key;
+ TDB_DATA kbuf;
+
+ memset(&key, '\0', sizeof(key));
+ key.device = dev;
+ key.inode = inode;
+ kbuf.dptr = (char *)&key;
+ kbuf.dsize = sizeof(key);
+ return kbuf;
+}
+
+/****************************************************************************
+ See if two locking contexts are equal.
+****************************************************************************/
+
+static BOOL brl_same_context(struct lock_context *ctx1,
+ struct lock_context *ctx2)
+{
+ return (ctx1->pid == ctx2->pid) &&
+ (ctx1->smbpid == ctx2->smbpid) &&
+ (ctx1->tid == ctx2->tid);
+}
+
+/****************************************************************************
+ See if lock2 can be added when lock1 is in place.
+****************************************************************************/
+
+static BOOL brl_conflict(struct lock_struct *lck1,
+ struct lock_struct *lck2)
+{
+ if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK) {
+ return False;
+ }
+
+ if (brl_same_context(&lck1->context, &lck2->context) &&
+ lck2->lock_type == READ_LOCK && lck1->fnum == lck2->fnum) {
+ return False;
+ }
+
+ if (lck1->start >= (lck2->start + lck2->size) ||
+ lck2->start >= (lck1->start + lck1->size)) {
+ return False;
+ }
+
+ return True;
+}
+
+#if ZERO_ZERO
+static BOOL brl_conflict1(struct lock_struct *lck1,
+ struct lock_struct *lck2)
+{
+ if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK) {
+ return False;
+ }
+
+ if (brl_same_context(&lck1->context, &lck2->context) &&
+ lck2->lock_type == READ_LOCK && lck1->fnum == lck2->fnum) {
+ return False;
+ }
+
+ if (lck2->start == 0 && lck2->size == 0 && lck1->size != 0) {
+ return True;
+ }
+
+ if (lck1->start >= (lck2->start + lck2->size) ||
+ lck2->start >= (lck1->start + lck1->size)) {
+ return False;
+ }
+
+ return True;
+}
+#endif
+
+/****************************************************************************
+ Check to see if this lock conflicts, but ignore our own locks on the
+ same fnum only.
+****************************************************************************/
+
+static BOOL brl_conflict_other(struct lock_struct *lck1, struct lock_struct *lck2)
+{
+ if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK)
+ return False;
+
+ if (brl_same_context(&lck1->context, &lck2->context) &&
+ lck1->fnum == lck2->fnum)
+ return False;
+
+ if (lck1->start >= (lck2->start + lck2->size) ||
+ lck2->start >= (lck1->start + lck1->size)) return False;
+
+ return True;
+}
+
+
+/****************************************************************************
+ Delete a record if it is for a dead process, if check_self is true, then
+ delete any records belonging to this pid also (there shouldn't be any).
+****************************************************************************/
+
+static int delete_fn(TDB_CONTEXT *ttdb, TDB_DATA kbuf, TDB_DATA dbuf, void *state)
+{
+ struct lock_struct *locks;
+ int count, i;
+ BOOL check_self = *(BOOL *)state;
+ pid_t mypid = sys_getpid();
+
+ tdb_chainlock(tdb, kbuf);
+
+ locks = (struct lock_struct *)dbuf.dptr;
+
+ count = dbuf.dsize / sizeof(*locks);
+ for (i=0; i<count; i++) {
+ struct lock_struct *lock = &locks[i];
+
+ /* If check_self is true we want to remove our own records. */
+ if (check_self && (mypid == lock->context.pid)) {
+
+ DEBUG(0,("brlock : delete_fn. LOGIC ERROR ! Shutting down and a record for my pid (%u) exists !\n",
+ (unsigned int)lock->context.pid ));
+
+ } else if (process_exists(lock->context.pid)) {
+
+ DEBUG(10,("brlock : delete_fn. pid %u exists.\n", (unsigned int)lock->context.pid ));
+ continue;
+ }
+
+ DEBUG(10,("brlock : delete_fn. Deleting record for process %u\n",
+ (unsigned int)lock->context.pid ));
+
+ if (count > 1 && i < count-1) {
+ memmove(&locks[i], &locks[i+1],
+ sizeof(*locks)*((count-1) - i));
+ }
+ count--;
+ i--;
+ }
+
+ if (count == 0) {
+ tdb_delete(tdb, kbuf);
+ } else if (count < (dbuf.dsize / sizeof(*locks))) {
+ dbuf.dsize = count * sizeof(*locks);
+ tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
+ }
+
+ tdb_chainunlock(tdb, kbuf);
+ return 0;
+}
+
+/****************************************************************************
+ Open up the brlock.tdb database.
+****************************************************************************/
+
+void brl_init(int read_only)
+{
+ BOOL check_self = False;
+
+ if (tdb)
+ return;
+ tdb = tdb_open_log(lock_path("brlock.tdb"), 0, TDB_DEFAULT|(read_only?0x0:TDB_CLEAR_IF_FIRST),
+ read_only?O_RDONLY:(O_RDWR|O_CREAT), 0644);
+ if (!tdb) {
+ DEBUG(0,("Failed to open byte range locking database\n"));
+ return;
+ }
+
+ /* delete any dead locks */
+ if (!read_only)
+ tdb_traverse(tdb, delete_fn, &check_self);
+}
+
+/****************************************************************************
+ Close down the brlock.tdb database.
+****************************************************************************/
+
+void brl_shutdown(int read_only)
+{
+ BOOL check_self = True;
+
+ if (!tdb)
+ return;
+
+ /* delete any dead locks */
+ if (!read_only)
+ tdb_traverse(tdb, delete_fn, &check_self);
+
+ tdb_close(tdb);
+}
+
+#if ZERO_ZERO
+/****************************************************************************
+compare two locks for sorting
+****************************************************************************/
+static int lock_compare(struct lock_struct *lck1,
+ struct lock_struct *lck2)
+{
+ if (lck1->start != lck2->start) return (lck1->start - lck2->start);
+ if (lck2->size != lck1->size) {
+ return ((int)lck1->size - (int)lck2->size);
+ }
+ return 0;
+}
+#endif
+
+/****************************************************************************
+ Lock a range of bytes.
+****************************************************************************/
+
+NTSTATUS brl_lock(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
+ uint16 smbpid, pid_t pid, uint16 tid,
+ br_off start, br_off size,
+ enum brl_type lock_type)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i;
+ struct lock_struct lock, *locks;
+ char *tp;
+ NTSTATUS status = NT_STATUS_OK;
+ static int last_failed = -1;
+ static br_off last_failed_start;
+
+ kbuf = locking_key(dev,ino);
+
+ dbuf.dptr = NULL;
+
+#if !ZERO_ZERO
+ if (start == 0 && size == 0) {
+ DEBUG(0,("client sent 0/0 lock - please report this\n"));
+ }
+#endif
+
+ tdb_chainlock(tdb, kbuf);
+ dbuf = tdb_fetch(tdb, kbuf);
+
+ lock.context.smbpid = smbpid;
+ lock.context.pid = pid;
+ lock.context.tid = tid;
+ lock.start = start;
+ lock.size = size;
+ lock.fnum = fnum;
+ lock.lock_type = lock_type;
+
+ if (dbuf.dptr) {
+ /* there are existing locks - make sure they don't conflict */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+ for (i=0; i<count; i++) {
+ if (brl_conflict(&locks[i], &lock)) {
+ status = NT_STATUS_LOCK_NOT_GRANTED;
+ goto fail;
+ }
+#if ZERO_ZERO
+ if (lock.start == 0 && lock.size == 0 &&
+ locks[i].size == 0) {
+ break;
+ }
+#endif
+ }
+ }
+
+ /* no conflicts - add it to the list of locks */
+ tp = Realloc(dbuf.dptr, dbuf.dsize + sizeof(*locks));
+ if (!tp) {
+ status = NT_STATUS_NO_MEMORY;
+ goto fail;
+ } else {
+ dbuf.dptr = tp;
+ }
+ memcpy(dbuf.dptr + dbuf.dsize, &lock, sizeof(lock));
+ dbuf.dsize += sizeof(lock);
+
+#if ZERO_ZERO
+ /* sort the lock list */
+ qsort(dbuf.dptr, dbuf.dsize/sizeof(lock), sizeof(lock), lock_compare);
+#endif
+
+ tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
+
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+ return NT_STATUS_OK;
+
+ fail:
+ /* this is a nasty hack to try to simulate the lock result cache code in w2k.
+ It isn't completely accurate as I haven't yet worked out the correct
+ semantics (tridge)
+ */
+ if (last_failed == fnum &&
+ last_failed_start == start &&
+ NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
+ status = NT_STATUS_FILE_LOCK_CONFLICT;
+ }
+ last_failed = fnum;
+ last_failed_start = start;
+
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+ return status;
+}
+
+/****************************************************************************
+ Unlock a range of bytes.
+****************************************************************************/
+
+BOOL brl_unlock(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
+ uint16 smbpid, pid_t pid, uint16 tid,
+ br_off start, br_off size)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i;
+ struct lock_struct *locks;
+ struct lock_context context;
+
+ kbuf = locking_key(dev,ino);
+
+ dbuf.dptr = NULL;
+
+ tdb_chainlock(tdb, kbuf);
+ dbuf = tdb_fetch(tdb, kbuf);
+
+ if (!dbuf.dptr) {
+ DEBUG(10,("brl_unlock: tdb_fetch failed !\n"));
+ goto fail;
+ }
+
+ context.smbpid = smbpid;
+ context.pid = pid;
+ context.tid = tid;
+
+ /* there are existing locks - find a match */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+
+#if ZERO_ZERO
+ for (i=0; i<count; i++) {
+ struct lock_struct *lock = &locks[i];
+
+ if (lock->lock_type == WRITE_LOCK &&
+ brl_same_context(&lock->context, &context) &&
+ lock->fnum == fnum &&
+ lock->start == start &&
+ lock->size == size) {
+ /* found it - delete it */
+ if (count == 1) {
+ tdb_delete(tdb, kbuf);
+ } else {
+ if (i < count-1) {
+ memmove(&locks[i], &locks[i+1],
+ sizeof(*locks)*((count-1) - i));
+ }
+ dbuf.dsize -= sizeof(*locks);
+ tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
+ }
+
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+ return True;
+ }
+ }
+#endif
+
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+ for (i=0; i<count; i++) {
+ struct lock_struct *lock = &locks[i];
+
+ if (brl_same_context(&lock->context, &context) &&
+ lock->fnum == fnum &&
+ lock->start == start &&
+ lock->size == size) {
+ /* found it - delete it */
+ if (count == 1) {
+ tdb_delete(tdb, kbuf);
+ } else {
+ if (i < count-1) {
+ memmove(&locks[i], &locks[i+1],
+ sizeof(*locks)*((count-1) - i));
+ }
+ dbuf.dsize -= sizeof(*locks);
+ tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
+ }
+
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+ return True;
+ }
+ }
+
+ /* we didn't find it */
+
+ fail:
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+ return False;
+}
+
+
+/****************************************************************************
+ Test if we could add a lock if we wanted to.
+****************************************************************************/
+
+BOOL brl_locktest(SMB_DEV_T dev, SMB_INO_T ino, int fnum,
+ uint16 smbpid, pid_t pid, uint16 tid,
+ br_off start, br_off size,
+ enum brl_type lock_type, int check_self)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i;
+ struct lock_struct lock, *locks;
+
+ kbuf = locking_key(dev,ino);
+
+ dbuf.dptr = NULL;
+
+ tdb_chainlock(tdb, kbuf);
+ dbuf = tdb_fetch(tdb, kbuf);
+
+ lock.context.smbpid = smbpid;
+ lock.context.pid = pid;
+ lock.context.tid = tid;
+ lock.start = start;
+ lock.size = size;
+ lock.fnum = fnum;
+ lock.lock_type = lock_type;
+
+ if (dbuf.dptr) {
+ /* there are existing locks - make sure they don't conflict */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+ for (i=0; i<count; i++) {
+ if (check_self) {
+ if (brl_conflict(&locks[i], &lock))
+ goto fail;
+ } else {
+ /*
+ * Our own locks don't conflict.
+ */
+ if (brl_conflict_other(&locks[i], &lock))
+ goto fail;
+ }
+ }
+ }
+
+ /* no conflicts - we could have added it */
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+ return True;
+
+ fail:
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+ return False;
+}
+
+/****************************************************************************
+ Remove any locks associated with a open file.
+****************************************************************************/
+
+void brl_close(SMB_DEV_T dev, SMB_INO_T ino, pid_t pid, int tid, int fnum)
+{
+ TDB_DATA kbuf, dbuf;
+ int count, i, dcount=0;
+ struct lock_struct *locks;
+
+ kbuf = locking_key(dev,ino);
+
+ dbuf.dptr = NULL;
+
+ tdb_chainlock(tdb, kbuf);
+ dbuf = tdb_fetch(tdb, kbuf);
+
+ if (!dbuf.dptr) goto fail;
+
+ /* there are existing locks - remove any for this fnum */
+ locks = (struct lock_struct *)dbuf.dptr;
+ count = dbuf.dsize / sizeof(*locks);
+ for (i=0; i<count; i++) {
+ struct lock_struct *lock = &locks[i];
+
+ if (lock->context.tid == tid &&
+ lock->context.pid == pid &&
+ lock->fnum == fnum) {
+ /* found it - delete it */
+ if (count > 1 && i < count-1) {
+ memmove(&locks[i], &locks[i+1],
+ sizeof(*locks)*((count-1) - i));
+ }
+ count--;
+ i--;
+ dcount++;
+ }
+ }
+
+ if (count == 0) {
+ tdb_delete(tdb, kbuf);
+ } else if (count < (dbuf.dsize / sizeof(*locks))) {
+ dbuf.dsize -= dcount * sizeof(*locks);
+ tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
+ }
+
+ /* we didn't find it */
+ fail:
+ SAFE_FREE(dbuf.dptr);
+ tdb_chainunlock(tdb, kbuf);
+}
+
+/****************************************************************************
+ Traverse the whole database with this function, calling traverse_callback
+ on each lock.
+****************************************************************************/
+
+static int traverse_fn(TDB_CONTEXT *ttdb, TDB_DATA kbuf, TDB_DATA dbuf, void *state)
+{
+ struct lock_struct *locks;
+ struct lock_key *key;
+ int i;
+
+ BRLOCK_FN(traverse_callback) = (BRLOCK_FN_CAST())state;
+
+ locks = (struct lock_struct *)dbuf.dptr;
+ key = (struct lock_key *)kbuf.dptr;
+
+ for (i=0;i<dbuf.dsize/sizeof(*locks);i++) {
+ traverse_callback(key->device, key->inode,
+ locks[i].context.pid,
+ locks[i].lock_type,
+ locks[i].start,
+ locks[i].size);
+ }
+ return 0;
+}
+
+/*******************************************************************
+ Call the specified function on each lock in the database.
+********************************************************************/
+
+int brl_forall(BRLOCK_FN(fn))
+{
+ if (!tdb) return 0;
+ return tdb_traverse(tdb, traverse_fn, (void *)fn);
+}
generated by cgit (git 2.34.1) at 2024-12-22 11:09:35 +0000