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authorAndrew Tridgell <tridge@samba.org>1996-06-10 03:39:58 +0000
committerAndrew Tridgell <tridge@samba.org>1996-06-10 03:39:58 +0000
commitde411c701ed79c02875807dc60ef035d8d08334d (patch)
treec0e04d7f916b10cb178f547f7aeef5a1d092d93d /source3/locking
parente2eac352b1c6534031ad89a5565d3668833a2bf1 (diff)
moved some more locking routines to locking.c, and moved replacement
routines for broken OSes from util.c to replace.c. (This used to be commit 3ee9d45426a9b3b584d1ffb9f81af26790a83b4c)
Diffstat (limited to 'source3/locking')
-rw-r--r--source3/locking/locking.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index 6ff3ab5d12..9ece771266 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -29,6 +29,137 @@ pstring share_del_pending="";
/****************************************************************************
+routine to do file locking
+****************************************************************************/
+BOOL fcntl_lock(int fd,int op,uint32 offset,uint32 count,int type)
+{
+#if HAVE_FCNTL_LOCK
+ struct flock lock;
+ int ret;
+
+#if 1
+ uint32 mask = 0xC0000000;
+
+ /* make sure the count is reasonable, we might kill the lockd otherwise */
+ count &= ~mask;
+
+ /* the offset is often strange - remove 2 of its bits if either of
+ the top two bits are set. Shift the top ones by two bits. This
+ still allows OLE2 apps to operate, but should stop lockd from
+ dieing */
+ if ((offset & mask) != 0)
+ offset = (offset & ~mask) | ((offset & mask) >> 2);
+#else
+ unsigned long mask = ((unsigned)1<<31);
+
+ /* interpret negative counts as large numbers */
+ if (count < 0)
+ count &= ~mask;
+
+ /* no negative offsets */
+ offset &= ~mask;
+
+ /* count + offset must be in range */
+ while ((offset < 0 || (offset + count < 0)) && mask)
+ {
+ offset &= ~mask;
+ mask = mask >> 1;
+ }
+#endif
+
+
+ DEBUG(5,("fcntl_lock %d %d %d %d %d\n",fd,op,(int)offset,(int)count,type));
+
+ lock.l_type = type;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = (int)offset;
+ lock.l_len = (int)count;
+ lock.l_pid = 0;
+
+ errno = 0;
+
+ ret = fcntl(fd,op,&lock);
+
+ if (errno != 0)
+ DEBUG(3,("fcntl lock gave errno %d (%s)\n",errno,strerror(errno)));
+
+ /* a lock query */
+ if (op == F_GETLK)
+ {
+ if ((ret != -1) &&
+ (lock.l_type != F_UNLCK) &&
+ (lock.l_pid != 0) &&
+ (lock.l_pid != getpid()))
+ {
+ DEBUG(3,("fd %d is locked by pid %d\n",fd,lock.l_pid));
+ return(True);
+ }
+
+ /* it must be not locked or locked by me */
+ return(False);
+ }
+
+ /* a lock set or unset */
+ if (ret == -1)
+ {
+ DEBUG(3,("lock failed at offset %d count %d op %d type %d (%s)\n",
+ offset,count,op,type,strerror(errno)));
+
+ /* perhaps it doesn't support this sort of locking?? */
+ if (errno == EINVAL)
+ {
+ DEBUG(3,("locking not supported? returning True\n"));
+ return(True);
+ }
+
+ return(False);
+ }
+
+ /* everything went OK */
+ DEBUG(5,("Lock call successful\n"));
+
+ return(True);
+#else
+ return(False);
+#endif
+}
+
+/*******************************************************************
+lock a file - returning a open file descriptor or -1 on failure
+The timeout is in seconds. 0 means no timeout
+********************************************************************/
+int file_lock(char *name,int timeout)
+{
+ int fd = open(name,O_RDWR|O_CREAT,0666);
+ time_t t=0;
+ if (fd < 0) return(-1);
+
+#if HAVE_FCNTL_LOCK
+ if (timeout) t = time(NULL);
+ while (!timeout || (time(NULL)-t < timeout)) {
+ if (fcntl_lock(fd,F_SETLK,0,1,F_WRLCK)) return(fd);
+ msleep(LOCK_RETRY_TIMEOUT);
+ }
+ return(-1);
+#else
+ return(fd);
+#endif
+}
+
+/*******************************************************************
+unlock a file locked by file_lock
+********************************************************************/
+void file_unlock(int fd)
+{
+ if (fd<0) return;
+#if HAVE_FCNTL_LOCK
+ fcntl_lock(fd,F_SETLK,0,1,F_UNLCK);
+#endif
+ close(fd);
+}
+
+
+/****************************************************************************
utility function called to see if a file region is locked
****************************************************************************/
BOOL is_locked(int fnum,int cnum,uint32 count,uint32 offset)