diff options
Diffstat (limited to 'source4/locking/posix.c')
| -rw-r--r-- | source4/locking/posix.c | 1313 |
1 files changed, 0 insertions, 1313 deletions
diff --git a/source4/locking/posix.c b/source4/locking/posix.c deleted file mode 100644 index 81690bace9..0000000000 --- a/source4/locking/posix.c +++ /dev/null @@ -1,1313 +0,0 @@ -/* - 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; -} |