From 8daa83a594a2e98f39d764422bfbdbc62c9efd44 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 19:20:00 +0200 Subject: Adding upstream version 2:4.20.0+dfsg. Signed-off-by: Daniel Baumann --- source3/locking/posix.c | 1371 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1371 insertions(+) create mode 100644 source3/locking/posix.c (limited to 'source3/locking/posix.c') diff --git a/source3/locking/posix.c b/source3/locking/posix.c new file mode 100644 index 0000000..eedbbc1 --- /dev/null +++ b/source3/locking/posix.c @@ -0,0 +1,1371 @@ +/* + 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 . + + Revision History: + + POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000. +*/ + +#include "includes.h" +#include "system/filesys.h" +#include "lib/util/server_id.h" +#include "locking/proto.h" +#include "dbwrap/dbwrap.h" +#include "dbwrap/dbwrap_rbt.h" +#include "util_tdb.h" +#include "smbd/fd_handle.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->fsp_flags.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. +****************************************************************************/ + +#define SMB_OFF_T_BITS (sizeof(off_t)*8) + +static bool posix_lock_in_range(off_t *offset_out, off_t *count_out, + uint64_t u_offset, uint64_t u_count) +{ + off_t offset = (off_t)u_offset; + off_t count = (off_t)u_count; + + /* + * For the type of system we are, attempt to + * find the maximum positive lock offset as an off_t. + */ + +#if defined(MAX_POSITIVE_LOCK_OFFSET) /* Some systems have arbitrary limits. */ + + off_t max_positive_lock_offset = (MAX_POSITIVE_LOCK_OFFSET); +#else + /* + * In this case off_t is 64 bits, + * and the underlying system can handle 64 bit signed locks. + */ + + off_t mask2 = ((off_t)0x4) << (SMB_OFF_T_BITS-4); + off_t mask = (mask2<<1); + off_t max_positive_lock_offset = ~mask; + +#endif + /* + * 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 == 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 & ~((uint64_t)max_positive_lock_offset)) { + DEBUG(10, ("posix_lock_in_range: (offset = %ju) offset > %ju " + "and we cannot handle this. Ignoring lock.\n", + (uintmax_t)u_offset, + (uintmax_t)max_positive_lock_offset)); + return False; + } + + /* + * We must truncate the count to less than max_positive_lock_offset. + */ + + if (u_count & ~((uint64_t)max_positive_lock_offset)) { + count = max_positive_lock_offset; + } + + /* + * Truncate count to end at max lock offset. + */ + + if (offset > INT64_MAX - count || + 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 = %ju, u_count = %ju\n", + (uintmax_t)u_offset, + (uintmax_t)u_count)); + return False; + } + + /* + * The mapping was successful. + */ + + DEBUG(10, ("posix_lock_in_range: offset_out = %ju, " + "count_out = %ju\n", + (uintmax_t)offset, (uintmax_t)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, off_t offset, off_t count, int type) +{ + bool ret; + + DEBUG(8,("posix_fcntl_lock %d %d %jd %jd %d\n", + fsp_get_io_fd(fsp),op,(intmax_t)offset,(intmax_t)count,type)); + + ret = SMB_VFS_LOCK(fsp, op, offset, count, type); + + if (!ret && ((errno == EFBIG) || (errno == ENOLCK) || (errno == EINVAL))) { + + if ((errno == EINVAL) && + (op != F_GETLK && + op != F_SETLK && + op != F_SETLKW)) { + DEBUG(0,("WARNING: OFD locks in use and no kernel " + "support. Try setting " + "'smbd:force process locks = true' " + "in smb.conf\n")); + } else { + DEBUG(0, ("WARNING: lock request at offset " + "%ju, length %ju returned\n", + (uintmax_t)offset, (uintmax_t)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 & ~((off_t)0x7fffffff)) { + DEBUG(0,("Offset greater than 31 bits. Returning success.\n")); + return True; + } + + if (count & ~((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, off_t *poffset, off_t *pcount, int *ptype) +{ + pid_t pid; + bool ret; + + DEBUG(8, ("posix_fcntl_getlock %d %ju %ju %d\n", + fsp_get_io_fd(fsp), (uintmax_t)*poffset, (uintmax_t)*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 %ju, length %ju returned\n", + (uintmax_t)*poffset, (uintmax_t)*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 & ~((off_t)0x7fffffff)) { + DEBUG(0,("Offset greater than 31 bits. Returning success.\n")); + return True; + } + + if (*pcount & ~((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, + uint64_t *pu_offset, + uint64_t *pu_count, + enum brl_type *plock_type, + enum brl_flavour lock_flav) +{ + off_t offset; + off_t count; + int posix_lock_type = map_posix_lock_type(fsp,*plock_type); + + DEBUG(10, ("is_posix_locked: File %s, offset = %ju, count = %ju, " + "type = %s\n", fsp_str_dbg(fsp), (uintmax_t)*pu_offset, + (uintmax_t)*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 = (uint64_t)offset; + *pu_count = (uint64_t)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(const 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(const files_struct *fsp) +{ + return make_tdb_data((const uint8_t *)&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 reference count of number of locks open + on a dev/ino pair. +****************************************************************************/ + +/**************************************************************************** + Increase the lock ref count. Creates lock_ref_count entry if it doesn't exist. +****************************************************************************/ + +static void increment_lock_ref_count(const files_struct *fsp) +{ + struct lock_ref_count_key tmp; + int32_t lock_ref_count = 0; + NTSTATUS status; + + status = dbwrap_change_int32_atomic( + posix_pending_close_db, locking_ref_count_key_fsp(fsp, &tmp), + &lock_ref_count, 1); + + SMB_ASSERT(NT_STATUS_IS_OK(status)); + SMB_ASSERT(lock_ref_count < INT32_MAX); + + DEBUG(10,("lock_ref_count for file %s = %d\n", + fsp_str_dbg(fsp), (int)(lock_ref_count + 1))); +} + +/**************************************************************************** + Reduce the lock ref count. +****************************************************************************/ + +static void decrement_lock_ref_count(const files_struct *fsp) +{ + struct lock_ref_count_key tmp; + int32_t lock_ref_count = 0; + NTSTATUS status; + + status = dbwrap_change_int32_atomic( + posix_pending_close_db, locking_ref_count_key_fsp(fsp, &tmp), + &lock_ref_count, -1); + + SMB_ASSERT(NT_STATUS_IS_OK(status)); + SMB_ASSERT(lock_ref_count > 0); + + DEBUG(10,("lock_ref_count for file %s = %d\n", + fsp_str_dbg(fsp), (int)(lock_ref_count - 1))); +} + +/**************************************************************************** + Fetch the lock ref count. +****************************************************************************/ + +static int32_t get_lock_ref_count(const files_struct *fsp) +{ + struct lock_ref_count_key tmp; + NTSTATUS status; + int32_t lock_ref_count = 0; + + status = dbwrap_fetch_int32( + posix_pending_close_db, locking_ref_count_key_fsp(fsp, &tmp), + &lock_ref_count); + + if (!NT_STATUS_IS_OK(status) && + !NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) { + DEBUG(0, ("Error fetching " + "lock ref count for file %s: %s\n", + fsp_str_dbg(fsp), nt_errstr(status))); + } + return lock_ref_count; +} + +/**************************************************************************** + Delete a lock_ref_count entry. +****************************************************************************/ + +static void delete_lock_ref_count(const files_struct *fsp) +{ + struct lock_ref_count_key tmp; + + /* Not a bug if it doesn't exist - no locks were ever granted. */ + + dbwrap_delete(posix_pending_close_db, + locking_ref_count_key_fsp(fsp, &tmp)); + + DEBUG(10,("delete_lock_ref_count for file %s\n", + fsp_str_dbg(fsp))); +} + +/**************************************************************************** + Next - the functions that deal with storing fd's that have outstanding + POSIX locks when closed. +****************************************************************************/ + +/**************************************************************************** + The records in posix_pending_close_db are composed of an array of + ints keyed by dev/ino pair. Those 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. +****************************************************************************/ + +struct add_fd_to_close_entry_state { + const struct files_struct *fsp; +}; + +static void add_fd_to_close_entry_fn( + struct db_record *rec, + TDB_DATA value, + void *private_data) +{ + struct add_fd_to_close_entry_state *state = private_data; + int fd = fsp_get_pathref_fd(state->fsp); + TDB_DATA values[] = { + value, + { .dptr = (uint8_t *)&fd, + .dsize = sizeof(fd) }, + }; + NTSTATUS status; + + SMB_ASSERT((values[0].dsize % sizeof(int)) == 0); + + status = dbwrap_record_storev(rec, values, ARRAY_SIZE(values), 0); + SMB_ASSERT(NT_STATUS_IS_OK(status)); +} + +/**************************************************************************** + Add an fd to the pending close db. +****************************************************************************/ + +static void add_fd_to_close_entry(const files_struct *fsp) +{ + struct add_fd_to_close_entry_state state = { .fsp = fsp }; + NTSTATUS status; + + status = dbwrap_do_locked( + posix_pending_close_db, + fd_array_key_fsp(fsp), + add_fd_to_close_entry_fn, + &state); + SMB_ASSERT(NT_STATUS_IS_OK(status)); + + DBG_DEBUG("added fd %d file %s\n", + fsp_get_pathref_fd(fsp), + fsp_str_dbg(fsp)); +} + +static void fd_close_posix_fn( + struct db_record *rec, + TDB_DATA data, + void *private_data) +{ + int *saved_errno = (int *)private_data; + size_t num_fds, i; + + SMB_ASSERT((data.dsize % sizeof(int)) == 0); + num_fds = data.dsize / sizeof(int); + + for (i=0; iconn->params) || + !lp_posix_locking(fsp->conn->params) || + fsp->fsp_flags.use_ofd_locks) + { + /* + * No locking or POSIX to worry about or we are using POSIX + * open file description lock semantics which only removes + * locks on the file descriptor we're closing. Just close. + */ + return close(fsp_get_pathref_fd(fsp)); + } + + if (get_lock_ref_count(fsp)) { + + /* + * There are outstanding locks on this dev/inode pair on + * other fds. Add our fd to the pending close db. We also + * set fsp_get_io_fd(fsp) to -1 inside fd_close() after returning + * from VFS layer. + */ + + add_fd_to_close_entry(fsp); + return 0; + } + + status = dbwrap_do_locked( + posix_pending_close_db, + fd_array_key_fsp(fsp), + fd_close_posix_fn, + &saved_errno); + if (!NT_STATUS_IS_OK(status)) { + DBG_WARNING("dbwrap_do_locked failed: %s\n", + nt_errstr(status)); + } + + /* Don't need a lock ref count on this dev/ino anymore. */ + delete_lock_ref_count(fsp); + + /* + * Finally close the fd associated with this fsp. + */ + + ret = close(fsp_get_pathref_fd(fsp)); + + 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; + off_t start; + 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. */ + 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=%ju,size=%ju\n", + (uintmax_t)lhead->start, (uintmax_t)lhead->size )); + + for (i=0; ilock_type != READ_LOCK && lock->lock_type != WRITE_LOCK) { + continue; + } + + /* Ignore locks not owned by this process. */ + if (!server_id_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=%ju: " + "start=%ju,size=%ju:type=%s", + (uintmax_t)lock->fnum, + (uintmax_t)lock->start, + (uintmax_t)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=%ju," + "size=%ju\n", + (uintmax_t)l_curr->start, + (uintmax_t)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=%ju," + "size=%ju\n", + (uintmax_t)l_curr->start, + (uintmax_t)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(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=%ju," + "size=%ju new: start=%ju," + "size=%ju\n", + (uintmax_t)l_curr->start, + (uintmax_t)l_curr->size, + (uintmax_t)l_new->start, + (uintmax_t)l_new->size )); + + /* + * Add into the dlink list after the l_curr point - NOT at lhead. + */ + DLIST_ADD_AFTER(lhead, l_new, l_curr); + + /* 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; + + if (asprintf(&msg, "logic flaw in cases: " + "l_curr: start = %ju, " + "size = %ju : lock: " + "start = %ju, size = %ju", + (uintmax_t)l_curr->start, + (uintmax_t)l_curr->size, + (uintmax_t)lock->start, + (uintmax_t)lock->size ) != -1) { + smb_panic(msg); + } else { + smb_panic("posix_lock_list"); + } + } + } /* end for ( l_curr = lhead; l_curr;) */ + } /* end for (i=0; istart = 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. */ + 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 = %ju, count = %ju\n", + posix_lock_type_name(posix_lock_type), + (uintmax_t)offset, (uintmax_t)count )); + + if (!posix_fcntl_lock(fsp,F_SETLK,offset,count,posix_lock_type)) { + *errno_ret = errno; + DEBUG(5, ("set_posix_lock_windows_flavour: Lock " + "fail !: Type = %s: offset = %ju, " + "count = %ju. Errno = %s\n", + posix_lock_type_name(posix_lock_type), + (uintmax_t)offset, (uintmax_t)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 = %ju, " + "count = %ju\n", + posix_lock_type_name(posix_lock_type), + (uintmax_t)offset, (uintmax_t)count )); + + posix_fcntl_lock(fsp,F_SETLK,offset,count,F_UNLCK); + } + } else { + /* Remember the number of locks we have on this dev/ino pair. */ + increment_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, + uint64_t u_offset, + uint64_t u_count, + enum brl_type deleted_lock_type, + const struct lock_context *lock_ctx, + const struct lock_struct *plocks, + int num_locks) +{ + off_t offset; + 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 = %ju, " + "count = %ju\n", fsp_str_dbg(fsp), + (uintmax_t)u_offset, (uintmax_t)u_count)); + + /* Remember the number of locks we have on this dev/ino pair. */ + decrement_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(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. */ + 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 = %ju, count = %ju\n", + (uintmax_t)offset, (uintmax_t)count )); + + if (!posix_fcntl_lock(fsp,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 = %ju, count = %ju\n", + (uintmax_t)offset, (uintmax_t)count )); + + if (!posix_fcntl_lock(fsp,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. +****************************************************************************/ + +/**************************************************************************** + We only increment the lock ref count when we see a POSIX lock on a context + that doesn't already have them. +****************************************************************************/ + +static void increment_posix_lock_count(const files_struct *fsp, + uint64_t smblctx) +{ + NTSTATUS status; + TDB_DATA ctx_key; + TDB_DATA val = { 0 }; + + ctx_key.dptr = (uint8_t *)&smblctx; + ctx_key.dsize = sizeof(smblctx); + + /* + * Don't increment if we already have any POSIX flavor + * locks on this context. + */ + if (dbwrap_exists(posix_pending_close_db, ctx_key)) { + return; + } + + /* Remember that we have POSIX flavor locks on this context. */ + status = dbwrap_store(posix_pending_close_db, ctx_key, val, 0); + SMB_ASSERT(NT_STATUS_IS_OK(status)); + + increment_lock_ref_count(fsp); + + DEBUG(10,("posix_locks set for file %s\n", + fsp_str_dbg(fsp))); +} + +static void decrement_posix_lock_count(const files_struct *fsp, uint64_t smblctx) +{ + NTSTATUS status; + TDB_DATA ctx_key; + + ctx_key.dptr = (uint8_t *)&smblctx; + ctx_key.dsize = sizeof(smblctx); + + status = dbwrap_delete(posix_pending_close_db, ctx_key); + SMB_ASSERT(NT_STATUS_IS_OK(status)); + + decrement_lock_ref_count(fsp); + + DEBUG(10,("posix_locks deleted for file %s\n", + fsp_str_dbg(fsp))); +} + +/**************************************************************************** + Return true if any locks exist on the given lock context. +****************************************************************************/ + +static bool locks_exist_on_context(const struct lock_struct *plocks, + int num_locks, + const struct lock_context *lock_ctx) +{ + int i; + + for (i=0; i < num_locks; i++) { + const struct lock_struct *lock = &plocks[i]; + + /* 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 (!server_id_equal(&lock->context.pid, &lock_ctx->pid)) { + continue; + } + + if (lock_ctx->smblctx == lock->context.smblctx) { + return true; + } + } + return false; +} + +/**************************************************************************** + 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, + uint64_t u_offset, + uint64_t u_count, + enum brl_type lock_type, + const struct lock_context *lock_ctx, + int *errno_ret) +{ + off_t offset; + off_t count; + int posix_lock_type = map_posix_lock_type(fsp,lock_type); + + DEBUG(5,("set_posix_lock_posix_flavour: File %s, offset = %ju, count " + "= %ju, type = %s\n", fsp_str_dbg(fsp), + (uintmax_t)u_offset, (uintmax_t)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_posix_lock_count(fsp, lock_ctx->smblctx); + return True; + } + + if (!posix_fcntl_lock(fsp,F_SETLK,offset,count,posix_lock_type)) { + *errno_ret = errno; + DEBUG(5,("set_posix_lock_posix_flavour: Lock fail !: Type = %s: offset = %ju, count = %ju. Errno = %s\n", + posix_lock_type_name(posix_lock_type), (intmax_t)offset, (intmax_t)count, strerror(errno) )); + return False; + } + increment_posix_lock_count(fsp, lock_ctx->smblctx); + 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, + uint64_t u_offset, + uint64_t u_count, + const struct lock_context *lock_ctx, + const struct lock_struct *plocks, + int num_locks) +{ + bool ret = True; + off_t offset; + 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 = %ju, " + "count = %ju\n", fsp_str_dbg(fsp), + (uintmax_t)u_offset, (uintmax_t)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)) { + if (!locks_exist_on_context(plocks, num_locks, lock_ctx)) { + decrement_posix_lock_count(fsp, lock_ctx->smblctx); + } + 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(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. */ + 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 = %ju, count = %ju\n", + (uintmax_t)offset, (uintmax_t)count )); + + if (!posix_fcntl_lock(fsp,F_SETLK,offset,count,F_UNLCK)) { + ret = False; + } + } + + if (!locks_exist_on_context(plocks, num_locks, lock_ctx)) { + decrement_posix_lock_count(fsp, lock_ctx->smblctx); + } + talloc_destroy(ul_ctx); + return ret; +} -- cgit v1.2.3