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Diffstat (limited to 'source3/locking/posix.c')
| -rw-r--r-- | source3/locking/posix.c | 1309 |
1 files changed, 1309 insertions, 0 deletions
diff --git a/source3/locking/posix.c b/source3/locking/posix.c new file mode 100644 index 0000000000..32e1ee9fbf --- /dev/null +++ b/source3/locking/posix.c @@ -0,0 +1,1309 @@ +/* + Unix SMB/CIFS implementation. + Locking functions + Copyright (C) Jeremy Allison 1992-2006 + + 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 3 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, see <http://www.gnu.org/licenses/>. + + Revision History: + + POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000. +*/ + +#include "includes.h" + +#undef DBGC_CLASS +#define DBGC_CLASS DBGC_LOCKING + +/* + * The pending close database handle. + */ + +static struct db_context *posix_pending_close_db; + +/**************************************************************************** + First - the functions that deal with the underlying system locks - these + functions are used no matter if we're mapping CIFS Windows locks or CIFS + POSIX locks onto POSIX. +****************************************************************************/ + +/**************************************************************************** + 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; + } + + /* + * 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; +} + +/**************************************************************************** + Debugging aid :-). +****************************************************************************/ + +static const char *posix_lock_type_name(int lock_type) +{ + return (lock_type == F_RDLCK) ? "READ" : "WRITE"; +} + +/**************************************************************************** + 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) +{ + bool ret; + + DEBUG(8,("posix_fcntl_lock %d %d %.0f %.0f %d\n",fsp->fh->fd,op,(double)offset,(double)count,type)); + + ret = SMB_VFS_LOCK(fsp, 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)); + DEBUGADD(0,("an %s error. This can happen when using 64 bit lock offsets\n", strerror(errno))); + DEBUGADD(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 = SMB_VFS_LOCK(fsp, op, offset, count, type); + } + } + + DEBUG(8,("posix_fcntl_lock: Lock call %s\n", ret ? "successful" : "failed")); + return ret; +} + +/**************************************************************************** + Actual function that gets POSIX locks. Copes with 64 -> 32 bit cruft and + broken NFS implementations. +****************************************************************************/ + +static bool posix_fcntl_getlock(files_struct *fsp, SMB_OFF_T *poffset, SMB_OFF_T *pcount, int *ptype) +{ + pid_t pid; + bool ret; + + DEBUG(8,("posix_fcntl_getlock %d %.0f %.0f %d\n", + fsp->fh->fd,(double)*poffset,(double)*pcount,*ptype)); + + ret = SMB_VFS_GETLOCK(fsp, poffset, pcount, ptype, &pid); + + if (!ret && ((errno == EFBIG) || (errno == ENOLCK) || (errno == EINVAL))) { + + DEBUG(0,("posix_fcntl_getlock: WARNING: lock request at offset %.0f, length %.0f returned\n", + (double)*poffset,(double)*pcount)); + DEBUGADD(0,("an %s error. This can happen when using 64 bit lock offsets\n", strerror(errno))); + DEBUGADD(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 (*poffset & ~((SMB_OFF_T)0x7fffffff)) { + DEBUG(0,("Offset greater than 31 bits. Returning success.\n")); + return True; + } + + if (*pcount & ~((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; + *pcount &= 0x7fffffff; + ret = SMB_VFS_GETLOCK(fsp,poffset,pcount,ptype,&pid); + } + } + + DEBUG(8,("posix_fcntl_getlock: Lock query 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 *pu_offset, + SMB_BIG_UINT *pu_count, + enum brl_type *plock_type, + enum brl_flavour lock_flav) +{ + SMB_OFF_T offset; + SMB_OFF_T count; + int posix_lock_type = map_posix_lock_type(fsp,*plock_type); + + DEBUG(10,("is_posix_locked: File %s, offset = %.0f, count = %.0f, type = %s\n", + fsp->fsp_name, (double)*pu_offset, (double)*pu_count, posix_lock_type_name(*plock_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, *pu_offset, *pu_count)) { + return False; + } + + if (!posix_fcntl_getlock(fsp,&offset,&count,&posix_lock_type)) { + return False; + } + + if (posix_lock_type == F_UNLCK) { + return False; + } + + if (lock_flav == POSIX_LOCK) { + /* Only POSIX lock queries need to know the details. */ + *pu_offset = (SMB_BIG_UINT)offset; + *pu_count = (SMB_BIG_UINT)count; + *plock_type = (posix_lock_type == F_RDLCK) ? READ_LOCK : WRITE_LOCK; + } + return True; +} + +/**************************************************************************** + Next - the functions that deal with in memory database storing representations + of either Windows CIFS locks or POSIX CIFS locks. +****************************************************************************/ + +/* The key used in the in-memory POSIX databases. */ + +struct lock_ref_count_key { + struct file_id id; + char r; +}; + +/******************************************************************* + Form a static locking key for a dev/inode pair for the lock ref count +******************************************************************/ + +static TDB_DATA locking_ref_count_key_fsp(files_struct *fsp, + struct lock_ref_count_key *tmp) +{ + ZERO_STRUCTP(tmp); + tmp->id = fsp->file_id; + tmp->r = 'r'; + return make_tdb_data((uint8_t *)tmp, sizeof(*tmp)); +} + +/******************************************************************* + Convenience function to get an fd_array key from an fsp. +******************************************************************/ + +static TDB_DATA fd_array_key_fsp(files_struct *fsp) +{ + return make_tdb_data((uint8 *)&fsp->file_id, sizeof(fsp->file_id)); +} + +/******************************************************************* + Create the in-memory POSIX lock databases. +********************************************************************/ + +bool posix_locking_init(bool read_only) +{ + if (posix_pending_close_db != NULL) { + return true; + } + + posix_pending_close_db = db_open_rbt(NULL); + + if (posix_pending_close_db == NULL) { + 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) +{ + /* + * Shouldn't we close all fd's here? + */ + TALLOC_FREE(posix_pending_close_db); + return true; +} + +/**************************************************************************** + Next - the functions that deal with storing fd's that have outstanding + POSIX locks when closed. +****************************************************************************/ + +/**************************************************************************** + The records in posix_pending_close_tdb are composed of an array of ints + keyed by dev/ino pair. + The first int is a reference count of the number of outstanding locks on + all open fd's on this dev/ino pair. Any subsequent ints are the fd's that + were open on this dev/ino pair that should have been closed, but can't as + the lock ref count is non zero. +****************************************************************************/ + +/**************************************************************************** + Keep a reference count of the number of Windows locks open on this dev/ino + pair. Creates entry if it doesn't exist. +****************************************************************************/ + +static void increment_windows_lock_ref_count(files_struct *fsp) +{ + struct lock_ref_count_key tmp; + struct db_record *rec; + int lock_ref_count = 0; + NTSTATUS status; + + rec = posix_pending_close_db->fetch_locked( + posix_pending_close_db, talloc_tos(), + locking_ref_count_key_fsp(fsp, &tmp)); + + SMB_ASSERT(rec != NULL); + + if (rec->value.dptr != NULL) { + SMB_ASSERT(rec->value.dsize == sizeof(lock_ref_count)); + memcpy(&lock_ref_count, rec->value.dptr, + sizeof(lock_ref_count)); + } + + lock_ref_count++; + + status = rec->store(rec, make_tdb_data((uint8 *)&lock_ref_count, + sizeof(lock_ref_count)), 0); + + SMB_ASSERT(NT_STATUS_IS_OK(status)); + + TALLOC_FREE(rec); + + DEBUG(10,("increment_windows_lock_ref_count for file now %s = %d\n", + fsp->fsp_name, lock_ref_count )); +} + +/**************************************************************************** + Bulk delete - subtract as many locks as we've just deleted. +****************************************************************************/ + +void reduce_windows_lock_ref_count(files_struct *fsp, unsigned int dcount) +{ + struct lock_ref_count_key tmp; + struct db_record *rec; + int lock_ref_count = 0; + NTSTATUS status; + + rec = posix_pending_close_db->fetch_locked( + posix_pending_close_db, talloc_tos(), + locking_ref_count_key_fsp(fsp, &tmp)); + + SMB_ASSERT((rec != NULL) + && (rec->value.dptr != NULL) + && (rec->value.dsize == sizeof(lock_ref_count))); + + memcpy(&lock_ref_count, rec->value.dptr, sizeof(lock_ref_count)); + + SMB_ASSERT(lock_ref_count > 0); + + lock_ref_count -= dcount; + + status = rec->store(rec, make_tdb_data((uint8 *)&lock_ref_count, + sizeof(lock_ref_count)), 0); + + SMB_ASSERT(NT_STATUS_IS_OK(status)); + + TALLOC_FREE(rec); + + DEBUG(10,("reduce_windows_lock_ref_count for file now %s = %d\n", + fsp->fsp_name, lock_ref_count )); +} + +static void decrement_windows_lock_ref_count(files_struct *fsp) +{ + reduce_windows_lock_ref_count(fsp, 1); +} + +/**************************************************************************** + Fetch the lock ref count. +****************************************************************************/ + +static int get_windows_lock_ref_count(files_struct *fsp) +{ + struct lock_ref_count_key tmp; + TDB_DATA dbuf; + int res; + int lock_ref_count = 0; + + res = posix_pending_close_db->fetch( + posix_pending_close_db, talloc_tos(), + locking_ref_count_key_fsp(fsp, &tmp), &dbuf); + + SMB_ASSERT(res == 0); + + if (dbuf.dsize != 0) { + SMB_ASSERT(dbuf.dsize == sizeof(lock_ref_count)); + memcpy(&lock_ref_count, dbuf.dptr, sizeof(lock_ref_count)); + TALLOC_FREE(dbuf.dptr); + } + + DEBUG(10,("get_windows_lock_count for file %s = %d\n", + fsp->fsp_name, lock_ref_count )); + + return lock_ref_count; +} + +/**************************************************************************** + Delete a lock_ref_count entry. +****************************************************************************/ + +static void delete_windows_lock_ref_count(files_struct *fsp) +{ + struct lock_ref_count_key tmp; + struct db_record *rec; + + rec = posix_pending_close_db->fetch_locked( + posix_pending_close_db, talloc_tos(), + locking_ref_count_key_fsp(fsp, &tmp)); + + SMB_ASSERT(rec != NULL); + + /* Not a bug if it doesn't exist - no locks were ever granted. */ + + rec->delete_rec(rec); + TALLOC_FREE(rec); + + DEBUG(10,("delete_windows_lock_ref_count for file %s\n", + fsp->fsp_name)); +} + +/**************************************************************************** + Add an fd to the pending close tdb. +****************************************************************************/ + +static void add_fd_to_close_entry(files_struct *fsp) +{ + struct db_record *rec; + uint8_t *new_data; + NTSTATUS status; + + rec = posix_pending_close_db->fetch_locked( + posix_pending_close_db, talloc_tos(), + fd_array_key_fsp(fsp)); + + SMB_ASSERT(rec != NULL); + + new_data = TALLOC_ARRAY( + rec, uint8_t, rec->value.dsize + sizeof(fsp->fh->fd)); + + SMB_ASSERT(new_data != NULL); + + memcpy(new_data, rec->value.dptr, rec->value.dsize); + memcpy(new_data + rec->value.dsize, + &fsp->fh->fd, sizeof(fsp->fh->fd)); + + status = rec->store( + rec, make_tdb_data(new_data, + rec->value.dsize + sizeof(fsp->fh->fd)), 0); + + SMB_ASSERT(NT_STATUS_IS_OK(status)); + + TALLOC_FREE(rec); + + DEBUG(10,("add_fd_to_close_entry: added fd %d file %s\n", + fsp->fh->fd, fsp->fsp_name )); +} + +/**************************************************************************** + Remove all fd entries for a specific dev/inode pair from the tdb. +****************************************************************************/ + +static void delete_close_entries(files_struct *fsp) +{ + struct db_record *rec; + + rec = posix_pending_close_db->fetch_locked( + posix_pending_close_db, talloc_tos(), + fd_array_key_fsp(fsp)); + + SMB_ASSERT(rec != NULL); + rec->delete_rec(rec); + TALLOC_FREE(rec); +} + +/**************************************************************************** + Get the array of POSIX pending close records for an open fsp. Returns number + of entries. +****************************************************************************/ + +static size_t get_posix_pending_close_entries(TALLOC_CTX *mem_ctx, + files_struct *fsp, int **entries) +{ + TDB_DATA dbuf; + int res; + + res = posix_pending_close_db->fetch( + posix_pending_close_db, mem_ctx, fd_array_key_fsp(fsp), + &dbuf); + + SMB_ASSERT(res == 0); + + if (dbuf.dsize == 0) { + *entries = NULL; + return 0; + } + + *entries = (int *)dbuf.dptr; + return (size_t)(dbuf.dsize / sizeof(int)); +} + +/**************************************************************************** + 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 files_struct *fsp) +{ + int saved_errno = 0; + int ret; + int *fd_array = NULL; + size_t count, i; + + if (!lp_locking(fsp->conn->params) || + !lp_posix_locking(fsp->conn->params)) + { + /* + * No locking or POSIX to worry about or we want POSIX semantics + * which will lose all locks on all fd's open on this dev/inode, + * just close. + */ + return close(fsp->fh->fd); + } + + if (get_windows_lock_ref_count(fsp)) { + + /* + * There are outstanding locks on this dev/inode pair on + * other fds. Add our fd to the pending close tdb and set + * fsp->fh->fd to -1. + */ + + add_fd_to_close_entry(fsp); + return 0; + } + + /* + * No outstanding locks. Get the pending close fd's + * from the tdb and close them all. + */ + + count = get_posix_pending_close_entries(talloc_tos(), 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 (close(fd_array[i]) == -1) { + saved_errno = errno; + } + } + + /* + * Delete all fd's stored in the tdb + * for this dev/inode pair. + */ + + delete_close_entries(fsp); + } + + TALLOC_FREE(fd_array); + + /* Don't need a lock ref count on this dev/ino anymore. */ + delete_windows_lock_ref_count(fsp); + + /* + * Finally close the fd associated with this fsp. + */ + + ret = close(fsp->fh->fd); + + if (ret == 0 && saved_errno != 0) { + errno = saved_errno; + ret = -1; + } + + return ret; +} + +/**************************************************************************** + Next - the functions that deal with the mapping CIFS Windows locks onto + the underlying system POSIX locks. +****************************************************************************/ + +/* + * 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, + const struct lock_context *lock_ctx, /* Lock context lhead belongs to. */ + files_struct *fsp, + const struct lock_struct *plocks, + int num_locks) +{ + int i; + + /* + * 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++) { + const struct lock_struct *lock = &plocks[i]; + struct lock_list *l_curr; + + /* Ignore all but read/write locks. */ + if (lock->lock_type != READ_LOCK && lock->lock_type != WRITE_LOCK) { + continue; + } + + /* Ignore locks not owned by this process. */ + if (!procid_equal(&lock->context.pid, &lock_ctx->pid)) { + continue; + } + + /* + * 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: fnum=%d: start=%.0f,size=%.0f:type=%s", lock->fnum, + (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 existing 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 range is completely overlapped by this existing lock range + * and thus should have no effect. 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 range 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 range 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. Range 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 l_new (as we + * know that l_new will not overlap with this lock). + */ +/********************************************* + +---------------------------+ + | l_curr | + +---------------------------+ + +---------+ + | lock | + +---------+ +BECOMES..... + +-------+ +---------+ + | l_curr| | l_new | + +-------+ +---------+ +**********************************************/ + struct lock_list *l_new = TALLOC_P(ctx, 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. + */ + char *msg = NULL; + + /* Don't check if alloc succeeds here - we're + * forcing a core dump anyway. */ + + asprintf(&msg, "logic flaw in cases: l_curr: start = %.0f, size = %.0f : \ +lock: start = %.0f, size = %.0f", (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++) */ + + return lhead; +} + +/**************************************************************************** + POSIX function to acquire a lock. Returns True if the + lock could be granted, False if not. +****************************************************************************/ + +bool set_posix_lock_windows_flavour(files_struct *fsp, + SMB_BIG_UINT u_offset, + SMB_BIG_UINT u_count, + enum brl_type lock_type, + const struct lock_context *lock_ctx, + const struct lock_struct *plocks, + int num_locks, + int *errno_ret) +{ + SMB_OFF_T offset; + SMB_OFF_T count; + int posix_lock_type = map_posix_lock_type(fsp,lock_type); + bool ret = True; + size_t lock_count; + TALLOC_CTX *l_ctx = NULL; + struct lock_list *llist = NULL; + struct lock_list *ll = NULL; + + DEBUG(5,("set_posix_lock_windows_flavour: 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)) { + increment_windows_lock_ref_count(fsp); + 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. + */ + + if ((l_ctx = talloc_init("set_posix_lock")) == NULL) { + DEBUG(0,("set_posix_lock_windows_flavour: unable to init talloc context.\n")); + return False; + } + + if ((ll = TALLOC_P(l_ctx, struct lock_list)) == NULL) { + DEBUG(0,("set_posix_lock_windows_flavour: unable to talloc unlock list.\n")); + talloc_destroy(l_ctx); + return False; + } + + /* + * 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, + lock_ctx, /* Lock context llist belongs to. */ + fsp, + plocks, + num_locks); + + /* + * 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_windows_flavour: 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)) { + *errno_ret = errno; + DEBUG(5,("set_posix_lock_windows_flavour: 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_windows_flavour: 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); + } + } else { + /* Remember the number of Windows locks we have on this dev/ino pair. */ + increment_windows_lock_ref_count(fsp); + } + + 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_windows_flavour(files_struct *fsp, + SMB_BIG_UINT u_offset, + SMB_BIG_UINT u_count, + enum brl_type deleted_lock_type, + const struct lock_context *lock_ctx, + const struct lock_struct *plocks, + int num_locks) +{ + 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; + + DEBUG(5,("release_posix_lock_windows_flavour: File %s, offset = %.0f, count = %.0f\n", + fsp->fsp_name, (double)u_offset, (double)u_count )); + + /* Remember the number of Windows locks we have on this dev/ino pair. */ + decrement_windows_lock_ref_count(fsp); + + /* + * 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; + } + + if ((ul_ctx = talloc_init("release_posix_lock")) == NULL) { + DEBUG(0,("release_posix_lock_windows_flavour: unable to init talloc context.\n")); + return False; + } + + if ((ul = TALLOC_P(ul_ctx, struct lock_list)) == NULL) { + DEBUG(0,("release_posix_lock_windows_flavour: unable to talloc unlock list.\n")); + talloc_destroy(ul_ctx); + return False; + } + + /* + * 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, + lock_ctx, /* Lock context ulist belongs to. */ + fsp, + plocks, + num_locks); + + /* + * If there were any overlapped entries (list is > 1 or size or start have changed), + * and the lock_type we just deleted from + * the upper layer tdb was a 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 (deleted_lock_type == WRITE_LOCK && + (!ulist || ulist->next != NULL || ulist->start != offset || ulist->size != count)) { + + DEBUG(5,("release_posix_lock_windows_flavour: downgrading lock to READ: offset = %.0f, count = %.0f\n", + (double)offset, (double)count )); + + if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_RDLCK)) { + DEBUG(0,("release_posix_lock_windows_flavour: downgrade of lock failed with error %s !\n", strerror(errno) )); + talloc_destroy(ul_ctx); + return False; + } + } + + /* + * 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_windows_flavour: 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; +} + +/**************************************************************************** + Next - the functions that deal with mapping CIFS POSIX locks onto + the underlying system POSIX locks. +****************************************************************************/ + +/**************************************************************************** + POSIX function to acquire a lock. Returns True if the + lock could be granted, False if not. + As POSIX locks don't stack or conflict (they just overwrite) + we can map the requested lock directly onto a system one. We + know it doesn't conflict with locks on other contexts as the + upper layer would have refused it. +****************************************************************************/ + +bool set_posix_lock_posix_flavour(files_struct *fsp, + SMB_BIG_UINT u_offset, + SMB_BIG_UINT u_count, + enum brl_type lock_type, + int *errno_ret) +{ + SMB_OFF_T offset; + SMB_OFF_T count; + int posix_lock_type = map_posix_lock_type(fsp,lock_type); + + DEBUG(5,("set_posix_lock_posix_flavour: 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; + } + + if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,posix_lock_type)) { + *errno_ret = errno; + DEBUG(5,("set_posix_lock_posix_flavour: Lock fail !: Type = %s: offset = %.0f, count = %.0f. Errno = %s\n", + posix_lock_type_name(posix_lock_type), (double)offset, (double)count, strerror(errno) )); + return False; + } + return True; +} + +/**************************************************************************** + POSIX function to release a lock. Returns True if the + lock could be released, False if not. + We are given a complete lock state from the upper layer which is what the lock + state should be after the unlock has already been done, so what + we do is punch out holes in the unlock range where locks owned by this process + have a different lock context. +****************************************************************************/ + +bool release_posix_lock_posix_flavour(files_struct *fsp, + SMB_BIG_UINT u_offset, + SMB_BIG_UINT u_count, + const struct lock_context *lock_ctx, + const struct lock_struct *plocks, + int num_locks) +{ + bool ret = True; + SMB_OFF_T offset; + SMB_OFF_T count; + TALLOC_CTX *ul_ctx = NULL; + struct lock_list *ulist = NULL; + struct lock_list *ul = NULL; + + DEBUG(5,("release_posix_lock_posix_flavour: 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; + } + + if ((ul_ctx = talloc_init("release_posix_lock")) == NULL) { + DEBUG(0,("release_posix_lock_windows_flavour: unable to init talloc context.\n")); + return False; + } + + if ((ul = TALLOC_P(ul_ctx, struct lock_list)) == NULL) { + DEBUG(0,("release_posix_lock_windows_flavour: unable to talloc unlock list.\n")); + talloc_destroy(ul_ctx); + return False; + } + + /* + * 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); + + /* + * Walk the given array creating a linked list + * of unlock requests. + */ + + ulist = posix_lock_list(ul_ctx, + ulist, + lock_ctx, /* Lock context ulist belongs to. */ + fsp, + plocks, + num_locks); + + /* + * 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_posix_flavour: 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; +} |