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-rw-r--r--source4/locking/posix.c1313
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diff --git a/source4/locking/posix.c b/source4/locking/posix.c
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--- /dev/null
+++ b/source4/locking/posix.c
@@ -0,0 +1,1313 @@
+/*
+ Unix SMB/CIFS implementation.
+ Locking functions
+ 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.
+
+ Revision History:
+
+ POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000.
+*/
+
+#include "includes.h"
+
+/*
+ * The POSIX locking database handle.
+ */
+
+static TDB_CONTEXT *posix_lock_tdb;
+
+/*
+ * The pending close database handle.
+ */
+
+static TDB_CONTEXT *posix_pending_close_tdb;
+
+/*
+ * The data in POSIX lock 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 posix_lock {
+ int fd;
+ SMB_OFF_T start;
+ SMB_OFF_T size;
+ int lock_type;
+};
+
+/*
+ * The data in POSIX pending close records is an unsorted linear array of int
+ * records. It is unnecessary to store the count as tdb provides the
+ * size of the record.
+ */
+
+/* The key used in both the POSIX databases. */
+
+struct posix_lock_key {
+ SMB_DEV_T device;
+ SMB_INO_T inode;
+};
+
+/*******************************************************************
+ Form a static locking key for a dev/inode pair.
+******************************************************************/
+
+static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
+{
+ static struct posix_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;
+}
+
+/*******************************************************************
+ Convenience function to get a key from an fsp.
+******************************************************************/
+
+static TDB_DATA locking_key_fsp(files_struct *fsp)
+{
+ return locking_key(fsp->dev, fsp->inode);
+}
+
+/****************************************************************************
+ Add an fd to the pending close tdb.
+****************************************************************************/
+
+static BOOL add_fd_to_close_entry(files_struct *fsp)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+ TDB_DATA dbuf;
+ char *tp;
+
+ dbuf.dptr = NULL;
+
+ dbuf = tdb_fetch(posix_pending_close_tdb, kbuf);
+
+ tp = Realloc(dbuf.dptr, dbuf.dsize + sizeof(int));
+ if (!tp) {
+ DEBUG(0,("add_fd_to_close_entry: Realloc fail !\n"));
+ SAFE_FREE(dbuf.dptr);
+ return False;
+ } else
+ dbuf.dptr = tp;
+
+ memcpy(dbuf.dptr + dbuf.dsize, &fsp->fd, sizeof(int));
+ dbuf.dsize += sizeof(int);
+
+ if (tdb_store(posix_pending_close_tdb, kbuf, dbuf, TDB_REPLACE) == -1) {
+ DEBUG(0,("add_fd_to_close_entry: tdb_store fail !\n"));
+ }
+
+ SAFE_FREE(dbuf.dptr);
+ return True;
+}
+
+/****************************************************************************
+ Remove all fd entries for a specific dev/inode pair from the tdb.
+****************************************************************************/
+
+static void delete_close_entries(files_struct *fsp)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+
+ if (tdb_delete(posix_pending_close_tdb, kbuf) == -1)
+ DEBUG(0,("delete_close_entries: tdb_delete fail !\n"));
+}
+
+/****************************************************************************
+ Get the array of POSIX pending close records for an open fsp. Caller must
+ free. Returns number of entries.
+****************************************************************************/
+
+static size_t get_posix_pending_close_entries(files_struct *fsp, int **entries)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+ TDB_DATA dbuf;
+ size_t count = 0;
+
+ *entries = NULL;
+ dbuf.dptr = NULL;
+
+ dbuf = tdb_fetch(posix_pending_close_tdb, kbuf);
+
+ if (!dbuf.dptr) {
+ return 0;
+ }
+
+ *entries = (int *)dbuf.dptr;
+ count = (size_t)(dbuf.dsize / sizeof(int));
+
+ return count;
+}
+
+/****************************************************************************
+ Get the array of POSIX locks for an fsp. Caller must free. Returns
+ number of entries.
+****************************************************************************/
+
+static size_t get_posix_lock_entries(files_struct *fsp, struct posix_lock **entries)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+ TDB_DATA dbuf;
+ size_t count = 0;
+
+ *entries = NULL;
+
+ dbuf.dptr = NULL;
+
+ dbuf = tdb_fetch(posix_lock_tdb, kbuf);
+
+ if (!dbuf.dptr) {
+ return 0;
+ }
+
+ *entries = (struct posix_lock *)dbuf.dptr;
+ count = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
+
+ return count;
+}
+
+/****************************************************************************
+ Deal with pending closes needed by POSIX locking support.
+ Note that posix_locking_close_file() is expected to have been called
+ to delete all locks on this fsp before this function is called.
+****************************************************************************/
+
+int fd_close_posix(struct tcon_context *conn, files_struct *fsp)
+{
+ int saved_errno = 0;
+ int ret;
+ size_t count, i;
+ struct posix_lock *entries = NULL;
+ int *fd_array = NULL;
+ BOOL locks_on_other_fds = False;
+
+ if (!lp_posix_locking(SNUM(conn))) {
+ /*
+ * No POSIX to worry about, just close.
+ */
+ ret = conn->vfs_ops.close(fsp,fsp->fd);
+ fsp->fd = -1;
+ return ret;
+ }
+
+ /*
+ * Get the number of outstanding POSIX locks on this dev/inode pair.
+ */
+
+ count = get_posix_lock_entries(fsp, &entries);
+
+ /*
+ * Check if there are any outstanding locks belonging to
+ * other fd's. This should never be the case if posix_locking_close_file()
+ * has been called first, but it never hurts to be *sure*.
+ */
+
+ for (i = 0; i < count; i++) {
+ if (entries[i].fd != fsp->fd) {
+ locks_on_other_fds = True;
+ break;
+ }
+ }
+
+ if (locks_on_other_fds) {
+
+ /*
+ * There are outstanding locks on this dev/inode pair on other fds.
+ * Add our fd to the pending close tdb and set fsp->fd to -1.
+ */
+
+ if (!add_fd_to_close_entry(fsp)) {
+ SAFE_FREE(entries);
+ return False;
+ }
+
+ SAFE_FREE(entries);
+ fsp->fd = -1;
+ return 0;
+ }
+
+ SAFE_FREE(entries);
+
+ /*
+ * No outstanding POSIX locks. Get the pending close fd's
+ * from the tdb and close them all.
+ */
+
+ count = get_posix_pending_close_entries(fsp, &fd_array);
+
+ if (count) {
+ DEBUG(10,("fd_close_posix: doing close on %u fd's.\n", (unsigned int)count ));
+
+ for(i = 0; i < count; i++) {
+ if (conn->vfs_ops.close(fsp,fd_array[i]) == -1) {
+ saved_errno = errno;
+ }
+ }
+
+ /*
+ * Delete all fd's stored in the tdb
+ * for this dev/inode pair.
+ */
+
+ delete_close_entries(fsp);
+ }
+
+ SAFE_FREE(fd_array);
+
+ /*
+ * Finally close the fd associated with this fsp.
+ */
+
+ ret = conn->vfs_ops.close(fsp,fsp->fd);
+
+ if (saved_errno != 0) {
+ errno = saved_errno;
+ ret = -1;
+ }
+
+ fsp->fd = -1;
+
+ return ret;
+}
+
+/****************************************************************************
+ Debugging aid :-).
+****************************************************************************/
+
+static const char *posix_lock_type_name(int lock_type)
+{
+ return (lock_type == F_RDLCK) ? "READ" : "WRITE";
+}
+
+/****************************************************************************
+ Delete a POSIX lock entry by index number. Used if the tdb add succeeds, but
+ then the POSIX fcntl lock fails.
+****************************************************************************/
+
+static BOOL delete_posix_lock_entry_by_index(files_struct *fsp, size_t entry)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+ TDB_DATA dbuf;
+ struct posix_lock *locks;
+ size_t count;
+
+ dbuf.dptr = NULL;
+
+ dbuf = tdb_fetch(posix_lock_tdb, kbuf);
+
+ if (!dbuf.dptr) {
+ DEBUG(10,("delete_posix_lock_entry_by_index: tdb_fetch failed !\n"));
+ goto fail;
+ }
+
+ count = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
+ locks = (struct posix_lock *)dbuf.dptr;
+
+ if (count == 1) {
+ tdb_delete(posix_lock_tdb, kbuf);
+ } else {
+ if (entry < count-1) {
+ memmove(&locks[entry], &locks[entry+1], sizeof(*locks)*((count-1) - entry));
+ }
+ dbuf.dsize -= sizeof(*locks);
+ tdb_store(posix_lock_tdb, kbuf, dbuf, TDB_REPLACE);
+ }
+
+ SAFE_FREE(dbuf.dptr);
+
+ return True;
+
+ fail:
+
+ SAFE_FREE(dbuf.dptr);
+ return False;
+}
+
+/****************************************************************************
+ Add an entry into the POSIX locking tdb. We return the index number of the
+ added lock (used in case we need to delete *exactly* this entry). Returns
+ False on fail, True on success.
+****************************************************************************/
+
+static BOOL add_posix_lock_entry(files_struct *fsp, SMB_OFF_T start, SMB_OFF_T size, int lock_type, size_t *pentry_num)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+ TDB_DATA dbuf;
+ struct posix_lock pl;
+ char *tp;
+
+ dbuf.dptr = NULL;
+
+ dbuf = tdb_fetch(posix_lock_tdb, kbuf);
+
+ *pentry_num = (size_t)(dbuf.dsize / sizeof(pl));
+
+ /*
+ * Add new record.
+ */
+
+ pl.fd = fsp->fd;
+ pl.start = start;
+ pl.size = size;
+ pl.lock_type = lock_type;
+
+ tp = Realloc(dbuf.dptr, dbuf.dsize + sizeof(pl));
+ if (!tp) {
+ DEBUG(0,("add_posix_lock_entry: Realloc fail !\n"));
+ goto fail;
+ } else
+ dbuf.dptr = tp;
+
+ memcpy(dbuf.dptr + dbuf.dsize, &pl, sizeof(pl));
+ dbuf.dsize += sizeof(pl);
+
+ if (tdb_store(posix_lock_tdb, kbuf, dbuf, TDB_REPLACE) == -1) {
+ DEBUG(0,("add_posix_lock: Failed to add lock entry on file %s\n", fsp->fsp_name));
+ goto fail;
+ }
+
+ SAFE_FREE(dbuf.dptr);
+
+ DEBUG(10,("add_posix_lock: File %s: type = %s: start=%.0f size=%.0f: dev=%.0f inode=%.0f\n",
+ fsp->fsp_name, posix_lock_type_name(lock_type), (double)start, (double)size,
+ (double)fsp->dev, (double)fsp->inode ));
+
+ return True;
+
+ fail:
+
+ SAFE_FREE(dbuf.dptr);
+ return False;
+}
+
+/****************************************************************************
+ Calculate if locks have any overlap at all.
+****************************************************************************/
+
+static BOOL does_lock_overlap(SMB_OFF_T start1, SMB_OFF_T size1, SMB_OFF_T start2, SMB_OFF_T size2)
+{
+ if (start1 >= start2 && start1 <= start2 + size2)
+ return True;
+
+ if (start1 < start2 && start1 + size1 > start2)
+ return True;
+
+ return False;
+}
+
+/****************************************************************************
+ Delete an entry from the POSIX locking tdb. Returns a copy of the entry being
+ deleted and the number of records that are overlapped by this one, or -1 on error.
+****************************************************************************/
+
+static int delete_posix_lock_entry(files_struct *fsp, SMB_OFF_T start, SMB_OFF_T size, struct posix_lock *pl)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+ TDB_DATA dbuf;
+ struct posix_lock *locks;
+ size_t i, count;
+ BOOL found = False;
+ int num_overlapping_records = 0;
+
+ dbuf.dptr = NULL;
+
+ dbuf = tdb_fetch(posix_lock_tdb, kbuf);
+
+ if (!dbuf.dptr) {
+ DEBUG(10,("delete_posix_lock_entry: tdb_fetch failed !\n"));
+ goto fail;
+ }
+
+ /* There are existing locks - find a match. */
+ locks = (struct posix_lock *)dbuf.dptr;
+ count = (size_t)(dbuf.dsize / sizeof(*locks));
+
+ /*
+ * Search for and delete the first record that matches the
+ * unlock criteria.
+ */
+
+ for (i=0; i<count; i++) {
+ struct posix_lock *entry = &locks[i];
+
+ if (entry->fd == fsp->fd &&
+ entry->start == start &&
+ entry->size == size) {
+
+ /* Make a copy if requested. */
+ if (pl)
+ *pl = *entry;
+
+ /* Found it - delete it. */
+ if (count == 1) {
+ tdb_delete(posix_lock_tdb, kbuf);
+ } else {
+ if (i < count-1) {
+ memmove(&locks[i], &locks[i+1], sizeof(*locks)*((count-1) - i));
+ }
+ dbuf.dsize -= sizeof(*locks);
+ tdb_store(posix_lock_tdb, kbuf, dbuf, TDB_REPLACE);
+ }
+ count--;
+ found = True;
+ break;
+ }
+ }
+
+ if (!found)
+ goto fail;
+
+ /*
+ * Count the number of entries that are
+ * overlapped by this unlock request.
+ */
+
+ for (i = 0; i < count; i++) {
+ struct posix_lock *entry = &locks[i];
+
+ if (fsp->fd == entry->fd &&
+ does_lock_overlap( start, size, entry->start, entry->size))
+ num_overlapping_records++;
+ }
+
+ DEBUG(10,("delete_posix_lock_entry: type = %s: start=%.0f size=%.0f, num_records = %d\n",
+ posix_lock_type_name(pl->lock_type), (double)pl->start, (double)pl->size,
+ (unsigned int)num_overlapping_records ));
+
+ SAFE_FREE(dbuf.dptr);
+
+ return num_overlapping_records;
+
+ fail:
+
+ SAFE_FREE(dbuf.dptr);
+ return -1;
+}
+
+/****************************************************************************
+ Utility function to map a lock type correctly depending on the open
+ mode of a file.
+****************************************************************************/
+
+static int map_posix_lock_type( files_struct *fsp, enum brl_type lock_type)
+{
+ if((lock_type == WRITE_LOCK) && !fsp->can_write) {
+ /*
+ * Many UNIX's cannot get a write lock on a file opened read-only.
+ * Win32 locking semantics allow this.
+ * Do the best we can and attempt a read-only lock.
+ */
+ DEBUG(10,("map_posix_lock_type: Downgrading write lock to read due to read-only file.\n"));
+ return F_RDLCK;
+ } else if((lock_type == READ_LOCK) && !fsp->can_read) {
+ /*
+ * Ditto for read locks on write only files.
+ */
+ DEBUG(10,("map_posix_lock_type: Changing read lock to write due to write-only file.\n"));
+ return F_WRLCK;
+ }
+
+ /*
+ * This return should be the most normal, as we attempt
+ * to always open files read/write.
+ */
+
+ return (lock_type == READ_LOCK) ? F_RDLCK : F_WRLCK;
+}
+
+/****************************************************************************
+ Check to see if the given unsigned lock range is within the possible POSIX
+ range. Modifies the given args to be in range if possible, just returns
+ False if not.
+****************************************************************************/
+
+static BOOL posix_lock_in_range(SMB_OFF_T *offset_out, SMB_OFF_T *count_out,
+ SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count)
+{
+ SMB_OFF_T offset = (SMB_OFF_T)u_offset;
+ SMB_OFF_T count = (SMB_OFF_T)u_count;
+
+ /*
+ * For the type of system we are, attempt to
+ * find the maximum positive lock offset as an SMB_OFF_T.
+ */
+
+#if defined(MAX_POSITIVE_LOCK_OFFSET) /* Some systems have arbitrary limits. */
+
+ SMB_OFF_T max_positive_lock_offset = (MAX_POSITIVE_LOCK_OFFSET);
+
+#elif defined(LARGE_SMB_OFF_T) && !defined(HAVE_BROKEN_FCNTL64_LOCKS)
+
+ /*
+ * In this case SMB_OFF_T is 64 bits,
+ * and the underlying system can handle 64 bit signed locks.
+ */
+
+ SMB_OFF_T mask2 = ((SMB_OFF_T)0x4) << (SMB_OFF_T_BITS-4);
+ SMB_OFF_T mask = (mask2<<1);
+ SMB_OFF_T max_positive_lock_offset = ~mask;
+
+#else /* !LARGE_SMB_OFF_T || HAVE_BROKEN_FCNTL64_LOCKS */
+
+ /*
+ * In this case either SMB_OFF_T is 32 bits,
+ * or the underlying system cannot handle 64 bit signed locks.
+ * All offsets & counts must be 2^31 or less.
+ */
+
+ SMB_OFF_T max_positive_lock_offset = 0x7FFFFFFF;
+
+#endif /* !LARGE_SMB_OFF_T || HAVE_BROKEN_FCNTL64_LOCKS */
+
+ /*
+ * POSIX locks of length zero mean lock to end-of-file.
+ * Win32 locks of length zero are point probes. Ignore
+ * any Win32 locks of length zero. JRA.
+ */
+
+ if (count == (SMB_OFF_T)0) {
+ DEBUG(10,("posix_lock_in_range: count = 0, ignoring.\n"));
+ return False;
+ }
+
+ /*
+ * If the given offset was > max_positive_lock_offset then we cannot map this at all
+ * ignore this lock.
+ */
+
+ if (u_offset & ~((SMB_BIG_UINT)max_positive_lock_offset)) {
+ DEBUG(10,("posix_lock_in_range: (offset = %.0f) offset > %.0f and we cannot handle this. Ignoring lock.\n",
+ (double)u_offset, (double)((SMB_BIG_UINT)max_positive_lock_offset) ));
+ return False;
+ }
+
+ /*
+ * We must truncate the count to less than max_positive_lock_offset.
+ */
+
+ if (u_count & ~((SMB_BIG_UINT)max_positive_lock_offset))
+ count = max_positive_lock_offset;
+
+ /*
+ * Truncate count to end at max lock offset.
+ */
+
+ if (offset + count < 0 || offset + count > max_positive_lock_offset)
+ count = max_positive_lock_offset - offset;
+
+ /*
+ * If we ate all the count, ignore this lock.
+ */
+
+ if (count == 0) {
+ DEBUG(10,("posix_lock_in_range: Count = 0. Ignoring lock u_offset = %.0f, u_count = %.0f\n",
+ (double)u_offset, (double)u_count ));
+ return False;
+ }
+
+ /*
+ * The mapping was successful.
+ */
+
+ DEBUG(10,("posix_lock_in_range: offset_out = %.0f, count_out = %.0f\n",
+ (double)offset, (double)count ));
+
+ *offset_out = offset;
+ *count_out = count;
+
+ return True;
+}
+
+/****************************************************************************
+ Actual function that does POSIX locks. Copes with 64 -> 32 bit cruft and
+ broken NFS implementations.
+****************************************************************************/
+
+static BOOL posix_fcntl_lock(files_struct *fsp, int op, SMB_OFF_T offset, SMB_OFF_T count, int type)
+{
+ int ret;
+ struct tcon_context *conn = fsp->conn;
+
+ DEBUG(8,("posix_fcntl_lock %d %d %.0f %.0f %d\n",fsp->fd,op,(double)offset,(double)count,type));
+
+ ret = conn->vfs_ops.lock(fsp,fsp->fd,op,offset,count,type);
+
+ if (!ret && ((errno == EFBIG) || (errno == ENOLCK) || (errno == EINVAL))) {
+
+ DEBUG(0,("posix_fcntl_lock: WARNING: lock request at offset %.0f, length %.0f returned\n",
+ (double)offset,(double)count));
+ DEBUG(0,("an %s error. This can happen when using 64 bit lock offsets\n", strerror(errno)));
+ DEBUG(0,("on 32 bit NFS mounted file systems.\n"));
+
+ /*
+ * If the offset is > 0x7FFFFFFF then this will cause problems on
+ * 32 bit NFS mounted filesystems. Just ignore it.
+ */
+
+ if (offset & ~((SMB_OFF_T)0x7fffffff)) {
+ DEBUG(0,("Offset greater than 31 bits. Returning success.\n"));
+ return True;
+ }
+
+ if (count & ~((SMB_OFF_T)0x7fffffff)) {
+ /* 32 bit NFS file system, retry with smaller offset */
+ DEBUG(0,("Count greater than 31 bits - retrying with 31 bit truncated length.\n"));
+ errno = 0;
+ count &= 0x7fffffff;
+ ret = conn->vfs_ops.lock(fsp,fsp->fd,op,offset,count,type);
+ }
+ }
+
+ DEBUG(8,("posix_fcntl_lock: Lock call %s\n", ret ? "successful" : "failed"));
+
+ return ret;
+}
+
+/****************************************************************************
+ POSIX function to see if a file region is locked. Returns True if the
+ region is locked, False otherwise.
+****************************************************************************/
+
+BOOL is_posix_locked(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count, enum brl_type lock_type)
+{
+ SMB_OFF_T offset;
+ SMB_OFF_T count;
+ int posix_lock_type = map_posix_lock_type(fsp,lock_type);
+
+ DEBUG(10,("is_posix_locked: File %s, offset = %.0f, count = %.0f, type = %s\n",
+ fsp->fsp_name, (double)u_offset, (double)u_count, posix_lock_type_name(lock_type) ));
+
+ /*
+ * If the requested lock won't fit in the POSIX range, we will
+ * never set it, so presume it is not locked.
+ */
+
+ if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
+ return False;
+
+ /*
+ * Note that most UNIX's can *test* for a write lock on
+ * a read-only fd, just not *set* a write lock on a read-only
+ * fd. So we don't need to use map_lock_type here.
+ */
+
+ return posix_fcntl_lock(fsp,SMB_F_GETLK,offset,count,posix_lock_type);
+}
+
+/*
+ * Structure used when splitting a lock range
+ * into a POSIX lock range. Doubly linked list.
+ */
+
+struct lock_list {
+ struct lock_list *next;
+ struct lock_list *prev;
+ SMB_OFF_T start;
+ SMB_OFF_T size;
+};
+
+/****************************************************************************
+ Create a list of lock ranges that don't overlap a given range. Used in calculating
+ POSIX locks and unlocks. This is a difficult function that requires ASCII art to
+ understand it :-).
+****************************************************************************/
+
+static struct lock_list *posix_lock_list(TALLOC_CTX *ctx, struct lock_list *lhead, files_struct *fsp)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+ TDB_DATA dbuf;
+ struct posix_lock *locks;
+ size_t num_locks, i;
+
+ dbuf.dptr = NULL;
+
+ dbuf = tdb_fetch(posix_lock_tdb, kbuf);
+
+ if (!dbuf.dptr)
+ return lhead;
+
+ locks = (struct posix_lock *)dbuf.dptr;
+ num_locks = (size_t)(dbuf.dsize / sizeof(*locks));
+
+ /*
+ * Check the current lock list on this dev/inode pair.
+ * Quit if the list is deleted.
+ */
+
+ DEBUG(10,("posix_lock_list: curr: start=%.0f,size=%.0f\n",
+ (double)lhead->start, (double)lhead->size ));
+
+ for (i=0; i<num_locks && lhead; i++) {
+
+ struct posix_lock *lock = &locks[i];
+ struct lock_list *l_curr;
+
+ /*
+ * Walk the lock list, checking for overlaps. Note that
+ * the lock list can expand within this loop if the current
+ * range being examined needs to be split.
+ */
+
+ for (l_curr = lhead; l_curr;) {
+
+ DEBUG(10,("posix_lock_list: lock: fd=%d: start=%.0f,size=%.0f:type=%s", lock->fd,
+ (double)lock->start, (double)lock->size, posix_lock_type_name(lock->lock_type) ));
+
+ if ( (l_curr->start >= (lock->start + lock->size)) ||
+ (lock->start >= (l_curr->start + l_curr->size))) {
+
+ /* No overlap with this lock - leave this range alone. */
+/*********************************************
+ +---------+
+ | l_curr |
+ +---------+
+ +-------+
+ | lock |
+ +-------+
+OR....
+ +---------+
+ | l_curr |
+ +---------+
+**********************************************/
+
+ DEBUG(10,("no overlap case.\n" ));
+
+ l_curr = l_curr->next;
+
+ } else if ( (l_curr->start >= lock->start) &&
+ (l_curr->start + l_curr->size <= lock->start + lock->size) ) {
+
+ /*
+ * This unlock is completely overlapped by this existing lock range
+ * and thus should have no effect (not be unlocked). Delete it from the list.
+ */
+/*********************************************
+ +---------+
+ | l_curr |
+ +---------+
+ +---------------------------+
+ | lock |
+ +---------------------------+
+**********************************************/
+ /* Save the next pointer */
+ struct lock_list *ul_next = l_curr->next;
+
+ DEBUG(10,("delete case.\n" ));
+
+ DLIST_REMOVE(lhead, l_curr);
+ if(lhead == NULL)
+ break; /* No more list... */
+
+ l_curr = ul_next;
+
+ } else if ( (l_curr->start >= lock->start) &&
+ (l_curr->start < lock->start + lock->size) &&
+ (l_curr->start + l_curr->size > lock->start + lock->size) ) {
+
+ /*
+ * This unlock overlaps the existing lock range at the high end.
+ * Truncate by moving start to existing range end and reducing size.
+ */
+/*********************************************
+ +---------------+
+ | l_curr |
+ +---------------+
+ +---------------+
+ | lock |
+ +---------------+
+BECOMES....
+ +-------+
+ | l_curr|
+ +-------+
+**********************************************/
+
+ l_curr->size = (l_curr->start + l_curr->size) - (lock->start + lock->size);
+ l_curr->start = lock->start + lock->size;
+
+ DEBUG(10,("truncate high case: start=%.0f,size=%.0f\n",
+ (double)l_curr->start, (double)l_curr->size ));
+
+ l_curr = l_curr->next;
+
+ } else if ( (l_curr->start < lock->start) &&
+ (l_curr->start + l_curr->size > lock->start) &&
+ (l_curr->start + l_curr->size <= lock->start + lock->size) ) {
+
+ /*
+ * This unlock overlaps the existing lock range at the low end.
+ * Truncate by reducing size.
+ */
+/*********************************************
+ +---------------+
+ | l_curr |
+ +---------------+
+ +---------------+
+ | lock |
+ +---------------+
+BECOMES....
+ +-------+
+ | l_curr|
+ +-------+
+**********************************************/
+
+ l_curr->size = lock->start - l_curr->start;
+
+ DEBUG(10,("truncate low case: start=%.0f,size=%.0f\n",
+ (double)l_curr->start, (double)l_curr->size ));
+
+ l_curr = l_curr->next;
+
+ } else if ( (l_curr->start < lock->start) &&
+ (l_curr->start + l_curr->size > lock->start + lock->size) ) {
+ /*
+ * Worst case scenario. Unlock request completely overlaps an existing
+ * lock range. Split the request into two, push the new (upper) request
+ * into the dlink list, and continue with the entry after ul_new (as we
+ * know that ul_new will not overlap with this lock).
+ */
+/*********************************************
+ +---------------------------+
+ | l_curr |
+ +---------------------------+
+ +---------+
+ | lock |
+ +---------+
+BECOMES.....
+ +-------+ +---------+
+ | l_curr| | l_new |
+ +-------+ +---------+
+**********************************************/
+ struct lock_list *l_new = (struct lock_list *)talloc(ctx,
+ sizeof(struct lock_list));
+
+ if(l_new == NULL) {
+ DEBUG(0,("posix_lock_list: talloc fail.\n"));
+ return NULL; /* The talloc_destroy takes care of cleanup. */
+ }
+
+ ZERO_STRUCTP(l_new);
+ l_new->start = lock->start + lock->size;
+ l_new->size = l_curr->start + l_curr->size - l_new->start;
+
+ /* Truncate the l_curr. */
+ l_curr->size = lock->start - l_curr->start;
+
+ DEBUG(10,("split case: curr: start=%.0f,size=%.0f \
+new: start=%.0f,size=%.0f\n", (double)l_curr->start, (double)l_curr->size,
+ (double)l_new->start, (double)l_new->size ));
+
+ /*
+ * Add into the dlink list after the l_curr point - NOT at lhead.
+ * Note we can't use DLINK_ADD here as this inserts at the head of the given list.
+ */
+
+ l_new->prev = l_curr;
+ l_new->next = l_curr->next;
+ l_curr->next = l_new;
+
+ /* And move after the link we added. */
+ l_curr = l_new->next;
+
+ } else {
+
+ /*
+ * This logic case should never happen. Ensure this is the
+ * case by forcing an abort.... Remove in production.
+ */
+ pstring msg;
+
+ slprintf(msg, sizeof(msg)-1, "logic flaw in cases: l_curr: start = %.0f, size = %.0f : \
+lock: start = %.0f, size = %.0f\n", (double)l_curr->start, (double)l_curr->size, (double)lock->start, (double)lock->size );
+
+ smb_panic(msg);
+ }
+ } /* end for ( l_curr = lhead; l_curr;) */
+ } /* end for (i=0; i<num_locks && ul_head; i++) */
+
+ SAFE_FREE(dbuf.dptr);
+
+ return lhead;
+}
+
+/****************************************************************************
+ POSIX function to acquire a lock. Returns True if the
+ lock could be granted, False if not.
+****************************************************************************/
+
+BOOL set_posix_lock(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count, enum brl_type lock_type)
+{
+ SMB_OFF_T offset;
+ SMB_OFF_T count;
+ BOOL ret = True;
+ size_t entry_num = 0;
+ size_t lock_count;
+ TALLOC_CTX *l_ctx = NULL;
+ struct lock_list *llist = NULL;
+ struct lock_list *ll = NULL;
+ int posix_lock_type = map_posix_lock_type(fsp,lock_type);
+
+ DEBUG(5,("set_posix_lock: File %s, offset = %.0f, count = %.0f, type = %s\n",
+ fsp->fsp_name, (double)u_offset, (double)u_count, posix_lock_type_name(lock_type) ));
+
+ /*
+ * If the requested lock won't fit in the POSIX range, we will
+ * pretend it was successful.
+ */
+
+ if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
+ return True;
+
+ /*
+ * Windows is very strange. It allows read locks to be overlayed
+ * (even over a write lock), but leaves the write lock in force until the first
+ * unlock. It also reference counts the locks. This means the following sequence :
+ *
+ * process1 process2
+ * ------------------------------------------------------------------------
+ * WRITE LOCK : start = 2, len = 10
+ * READ LOCK: start =0, len = 10 - FAIL
+ * READ LOCK : start = 0, len = 14
+ * READ LOCK: start =0, len = 10 - FAIL
+ * UNLOCK : start = 2, len = 10
+ * READ LOCK: start =0, len = 10 - OK
+ *
+ * Under POSIX, the same sequence in steps 1 and 2 would not be reference counted, but
+ * would leave a single read lock over the 0-14 region. In order to
+ * re-create Windows semantics mapped to POSIX locks, we create multiple TDB
+ * entries, one for each overlayed lock request. We are guarenteed by the brlock
+ * semantics that if a write lock is added, then it will be first in the array.
+ */
+
+ if ((l_ctx = talloc_init("set_posix_lock")) == NULL) {
+ DEBUG(0,("set_posix_lock: unable to init talloc context.\n"));
+ return True; /* Not a fatal error. */
+ }
+
+ if ((ll = (struct lock_list *)talloc(l_ctx, sizeof(struct lock_list))) == NULL) {
+ DEBUG(0,("set_posix_lock: unable to talloc unlock list.\n"));
+ talloc_destroy(l_ctx);
+ return True; /* Not a fatal error. */
+ }
+
+ /*
+ * Create the initial list entry containing the
+ * lock we want to add.
+ */
+
+ ZERO_STRUCTP(ll);
+ ll->start = offset;
+ ll->size = count;
+
+ DLIST_ADD(llist, ll);
+
+ /*
+ * The following call calculates if there are any
+ * overlapping locks held by this process on
+ * fd's open on the same file and splits this list
+ * into a list of lock ranges that do not overlap with existing
+ * POSIX locks.
+ */
+
+ llist = posix_lock_list(l_ctx, llist, fsp);
+
+ /*
+ * Now we have the list of ranges to lock it is safe to add the
+ * entry into the POSIX lock tdb. We take note of the entry we
+ * added here in case we have to remove it on POSIX lock fail.
+ */
+
+ if (!add_posix_lock_entry(fsp,offset,count,posix_lock_type,&entry_num)) {
+ DEBUG(0,("set_posix_lock: Unable to create posix lock entry !\n"));
+ talloc_destroy(l_ctx);
+ return False;
+ }
+
+ /*
+ * Add the POSIX locks on the list of ranges returned.
+ * As the lock is supposed to be added atomically, we need to
+ * back out all the locks if any one of these calls fail.
+ */
+
+ for (lock_count = 0, ll = llist; ll; ll = ll->next, lock_count++) {
+ offset = ll->start;
+ count = ll->size;
+
+ DEBUG(5,("set_posix_lock: Real lock: Type = %s: offset = %.0f, count = %.0f\n",
+ posix_lock_type_name(posix_lock_type), (double)offset, (double)count ));
+
+ if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,posix_lock_type)) {
+ DEBUG(5,("set_posix_lock: Lock fail !: Type = %s: offset = %.0f, count = %.0f. Errno = %s\n",
+ posix_lock_type_name(posix_lock_type), (double)offset, (double)count, strerror(errno) ));
+ ret = False;
+ break;
+ }
+ }
+
+ if (!ret) {
+
+ /*
+ * Back out all the POSIX locks we have on fail.
+ */
+
+ for (ll = llist; lock_count; ll = ll->next, lock_count--) {
+ offset = ll->start;
+ count = ll->size;
+
+ DEBUG(5,("set_posix_lock: Backing out locks: Type = %s: offset = %.0f, count = %.0f\n",
+ posix_lock_type_name(posix_lock_type), (double)offset, (double)count ));
+
+ posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_UNLCK);
+ }
+
+ /*
+ * Remove the tdb entry for this lock.
+ */
+
+ delete_posix_lock_entry_by_index(fsp,entry_num);
+ }
+
+ talloc_destroy(l_ctx);
+ return ret;
+}
+
+/****************************************************************************
+ POSIX function to release a lock. Returns True if the
+ lock could be released, False if not.
+****************************************************************************/
+
+BOOL release_posix_lock(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count)
+{
+ SMB_OFF_T offset;
+ SMB_OFF_T count;
+ BOOL ret = True;
+ TALLOC_CTX *ul_ctx = NULL;
+ struct lock_list *ulist = NULL;
+ struct lock_list *ul = NULL;
+ struct posix_lock deleted_lock;
+ int num_overlapped_entries;
+
+ DEBUG(5,("release_posix_lock: File %s, offset = %.0f, count = %.0f\n",
+ fsp->fsp_name, (double)u_offset, (double)u_count ));
+
+ /*
+ * If the requested lock won't fit in the POSIX range, we will
+ * pretend it was successful.
+ */
+
+ if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
+ return True;
+
+ /*
+ * We treat this as one unlock request for POSIX accounting purposes even
+ * if it may later be split into multiple smaller POSIX unlock ranges.
+ * num_overlapped_entries is the number of existing locks that have any
+ * overlap with this unlock request.
+ */
+
+ num_overlapped_entries = delete_posix_lock_entry(fsp, offset, count, &deleted_lock);
+
+ if (num_overlapped_entries == -1) {
+ smb_panic("release_posix_lock: unable find entry to delete !\n");
+ }
+
+ /*
+ * If num_overlapped_entries is > 0, and the lock_type we just deleted from the tdb was
+ * a POSIX write lock, then before doing the unlock we need to downgrade
+ * the POSIX lock to a read lock. This allows any overlapping read locks
+ * to be atomically maintained.
+ */
+
+ if (num_overlapped_entries > 0 && deleted_lock.lock_type == F_WRLCK) {
+ if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_RDLCK)) {
+ DEBUG(0,("release_posix_lock: downgrade of lock failed with error %s !\n", strerror(errno) ));
+ return False;
+ }
+ }
+
+ if ((ul_ctx = talloc_init("release_posix_lock")) == NULL) {
+ DEBUG(0,("release_posix_lock: unable to init talloc context.\n"));
+ return True; /* Not a fatal error. */
+ }
+
+ if ((ul = (struct lock_list *)talloc(ul_ctx, sizeof(struct lock_list))) == NULL) {
+ DEBUG(0,("release_posix_lock: unable to talloc unlock list.\n"));
+ talloc_destroy(ul_ctx);
+ return True; /* Not a fatal error. */
+ }
+
+ /*
+ * Create the initial list entry containing the
+ * lock we want to remove.
+ */
+
+ ZERO_STRUCTP(ul);
+ ul->start = offset;
+ ul->size = count;
+
+ DLIST_ADD(ulist, ul);
+
+ /*
+ * The following call calculates if there are any
+ * overlapping locks held by this process on
+ * fd's open on the same file and creates a
+ * list of unlock ranges that will allow
+ * POSIX lock ranges to remain on the file whilst the
+ * unlocks are performed.
+ */
+
+ ulist = posix_lock_list(ul_ctx, ulist, fsp);
+
+ /*
+ * Release the POSIX locks on the list of ranges returned.
+ */
+
+ for(; ulist; ulist = ulist->next) {
+ offset = ulist->start;
+ count = ulist->size;
+
+ DEBUG(5,("release_posix_lock: Real unlock: offset = %.0f, count = %.0f\n",
+ (double)offset, (double)count ));
+
+ if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_UNLCK))
+ ret = False;
+ }
+
+ talloc_destroy(ul_ctx);
+
+ return ret;
+}
+
+/****************************************************************************
+ Remove all lock entries for a specific dev/inode pair from the tdb.
+****************************************************************************/
+
+static void delete_posix_lock_entries(files_struct *fsp)
+{
+ TDB_DATA kbuf = locking_key_fsp(fsp);
+
+ if (tdb_delete(posix_lock_tdb, kbuf) == -1)
+ DEBUG(0,("delete_close_entries: tdb_delete fail !\n"));
+}
+
+/****************************************************************************
+ Debug function.
+****************************************************************************/
+
+static void dump_entry(struct posix_lock *pl)
+{
+ DEBUG(10,("entry: start=%.0f, size=%.0f, type=%d, fd=%i\n",
+ (double)pl->start, (double)pl->size, (int)pl->lock_type, pl->fd ));
+}
+
+/****************************************************************************
+ Remove any locks on this fd. Called from file_close().
+****************************************************************************/
+
+void posix_locking_close_file(files_struct *fsp)
+{
+ struct posix_lock *entries = NULL;
+ size_t count, i;
+
+ /*
+ * Optimization for the common case where we are the only
+ * opener of a file. If all fd entries are our own, we don't
+ * need to explicitly release all the locks via the POSIX functions,
+ * we can just remove all the entries in the tdb and allow the
+ * close to remove the real locks.
+ */
+
+ count = get_posix_lock_entries(fsp, &entries);
+
+ if (count == 0) {
+ DEBUG(10,("posix_locking_close_file: file %s has no outstanding locks.\n", fsp->fsp_name ));
+ return;
+ }
+
+ for (i = 0; i < count; i++) {
+ if (entries[i].fd != fsp->fd )
+ break;
+
+ dump_entry(&entries[i]);
+ }
+
+ if (i == count) {
+ /* All locks are ours. */
+ DEBUG(10,("posix_locking_close_file: file %s has %u outstanding locks, but all on one fd.\n",
+ fsp->fsp_name, (unsigned int)count ));
+ SAFE_FREE(entries);
+ delete_posix_lock_entries(fsp);
+ return;
+ }
+
+ /*
+ * Difficult case. We need to delete all our locks, whilst leaving
+ * all other POSIX locks in place.
+ */
+
+ for (i = 0; i < count; i++) {
+ struct posix_lock *pl = &entries[i];
+ if (pl->fd == fsp->fd)
+ release_posix_lock(fsp, (SMB_BIG_UINT)pl->start, (SMB_BIG_UINT)pl->size );
+ }
+ SAFE_FREE(entries);
+}
+
+/*******************************************************************
+ Create the in-memory POSIX lock databases.
+********************************************************************/
+
+BOOL posix_locking_init(int read_only)
+{
+ if (posix_lock_tdb && posix_pending_close_tdb)
+ return True;
+
+ if (!posix_lock_tdb)
+ posix_lock_tdb = tdb_open_log(NULL, 0, TDB_INTERNAL,
+ read_only?O_RDONLY:(O_RDWR|O_CREAT), 0644);
+ if (!posix_lock_tdb) {
+ DEBUG(0,("Failed to open POSIX byte range locking database.\n"));
+ return False;
+ }
+ if (!posix_pending_close_tdb)
+ posix_pending_close_tdb = tdb_open_log(NULL, 0, TDB_INTERNAL,
+ read_only?O_RDONLY:(O_RDWR|O_CREAT), 0644);
+ if (!posix_pending_close_tdb) {
+ DEBUG(0,("Failed to open POSIX pending close database.\n"));
+ return False;
+ }
+
+ return True;
+}
+
+/*******************************************************************
+ Delete the in-memory POSIX lock databases.
+********************************************************************/
+
+BOOL posix_locking_end(void)
+{
+ if (posix_lock_tdb && tdb_close(posix_lock_tdb) != 0)
+ return False;
+ if (posix_pending_close_tdb && tdb_close(posix_pending_close_tdb) != 0)
+ return False;
+ return True;
+}
generated by cgit (git 2.34.1) at 2024-11-10 16:20:59 +0000