Changeset 688

Timestamp:

Sep 11, 2003, 3:16:25 AM (22 years ago)

Author:

bird

Message:

#634: Implemented flock() using fcntl().

File:

• trunk/src/emx/src/lib/io/flock.c (modified) (1 diff, 1 prop)

trunk/src/emx/src/lib/io/flock.c

@@ -2 +2 @@
 
 #include "libc-alias.h"
-#include <sys/file.h>
+#include <io.h>
+#include <sys/fcntl.h>
+#include <limits.h>
 #include <errno.h>
 #include <emx/io.h>
 
-int _STD(flock) (int handle, int operation)
+/** @todo update limit.h to FreeBSD 5.1 or later. */
+#ifndef OFF_MAX
+#define OFF_MAX LONG_MAX
+#endif
+
+/** @todo check that fcntl is ok for flock implementation, have seen
+ * comments and #defines in both Linux and FreeBSD which hints that
+ * this isn't exactly the same thing.
+ * @todo check thread safety as I see FreeBSD is taking that into account.
+ */
+int _STD(flock) (int fd, int request)
 {
-  if (_fd_flags (handle) == NULL)
+  struct flock  flck;
+  int           fcntl_request;
+
+  /* init the struct with defaults */
+  flck.l_start = 0;
+  flck.l_len = OFF_MAX;
+  flck.l_whence = SEEK_SET;
+  flck.l_pid = 0;
+  if (request & LOCK_NB)
+    fcntl_request = F_SETLK;            /* don't block when locking */
+  else
+    fcntl_request = F_SETLKW;
+
+  /* what to do */
+  switch (request & (LOCK_SH | LOCK_EX | LOCK_UN))
     {
-      errno = EBADF;
-      return -1;
+      /* shared file lock */
+      case LOCK_SH:
+          flck.l_type = F_RDLCK;
+          break;
+      /* exclusive file lock */
+      case LOCK_EX:
+          flck.l_type = F_WRLCK;
+          break;
+
+      /* unlock file */
+      case LOCK_UN:
+          flck.l_type = F_UNLCK;
+          fcntl_request = F_SETLK;      /* doesn't hurt I think? */
+          break;
+
+      default:
+          errno = EINVAL;
+          return -1;
     }
-  /*...this is a dummy function...*/
-  return 0;
+
+  /* do work */
+  return fcntl(fd, fcntl_request, &flck);
 }
+