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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/locking.c
parente2eac352b1c6534031ad89a5565d3668833a2bf1 (diff)
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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/locking.c')
-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)