util: Get rid of virFileFlock()

It was created to get rid of conditional compilation in the resctrl code and
make it usable anywhere else.  However this is not something that is going to be
used in other places because it is not portable and resctrl is just very
specific in this regard.  And there is no reason why there could not be a
preprocessor conditional in the resctrl code.  Also the interface of
virFileFlock() was very ambiguous which lead to some issues.

Signed-off-by: Martin Kletzander <[email protected]>
Reviewed-by: Andrea Bolognani <[email protected]>
Reviewed-by: Ján Tomko <[email protected]>

Author: nertpinx

src/libvirt_private.syms

@@ -2076,7 +2076,6 @@ virFileFindHugeTLBFS;
 virFileFindMountPoint;
 virFileFindResource;
 virFileFindResourceFull;
-virFileFlock;
 virFileFreeACLs;
 virFileGetACLs;
 virFileGetDefaultHugepage;

src/util/virfile.c

@@ -463,30 +463,9 @@ int virFileUnlock(int fd, off_t start, off_t len)
 }
 
 
-/**
- * virFileFlock:
- * @fd: file descriptor to call flock on
- * @lock: true for lock, false for unlock
- * @shared: true if shared, false for exclusive, ignored if `@lock == false`
- *
- * This is just a simple wrapper around flock(2) that errors out on unsupported
- * platforms.
- *
- * The lock will be released when @fd is closed or this function is called with
- * `@lock == false`.
- *
- * Returns 0 on success, -1 otherwise (with errno set)
- */
-int virFileFlock(int fd, bool lock, bool shared)
-{
-    if (lock)
-        return flock(fd, shared ? LOCK_SH : LOCK_EX);
-
-    return flock(fd, LOCK_UN);
-}
-
 #else /* WIN32 */
 
+
 int virFileLock(int fd G_GNUC_UNUSED,
                 bool shared G_GNUC_UNUSED,
                 off_t start G_GNUC_UNUSED,
@@ -505,14 +484,6 @@ int virFileUnlock(int fd G_GNUC_UNUSED,
 }
 
 
-int virFileFlock(int fd G_GNUC_UNUSED,
-                 bool lock G_GNUC_UNUSED,
-                 bool shared G_GNUC_UNUSED)
-{
-    errno = ENOSYS;
-    return -1;
-}
-
 #endif /* WIN32 */
 
 

src/util/virfile.h

@@ -118,8 +118,6 @@ int virFileLock(int fd, bool shared, off_t start, off_t len, bool waitForLock)
 int virFileUnlock(int fd, off_t start, off_t len)
     G_GNUC_NO_INLINE;
 
-int virFileFlock(int fd, bool lock, bool shared);
-
 typedef int (*virFileRewriteFunc)(int fd, const void *opaque);
 int virFileRewrite(const char *path,
                    mode_t mode,

src/util/virresctrl.c

@@ -453,6 +453,8 @@ VIR_ONCE_GLOBAL_INIT(virResctrl);
 
 
 /* Common functions */
+#ifndef WIN32
+
 static int
 virResctrlLockWrite(void)
 {
@@ -463,7 +465,7 @@ virResctrlLockWrite(void)
         return -1;
     }
 
-    if (virFileFlock(fd, true, false) < 0) {
+    if (flock(fd, LOCK_EX) < 0) {
         virReportSystemError(errno, "%s", _("Cannot lock resctrl"));
         VIR_FORCE_CLOSE(fd);
         return -1;
@@ -485,7 +487,7 @@ virResctrlUnlock(int fd)
         virReportSystemError(errno, "%s", _("Cannot close resctrl"));
 
         /* Trying to save the already broken */
-        if (virFileFlock(fd, false, false) < 0)
+        if (flock(fd, LOCK_UN) < 0)
             virReportSystemError(errno, "%s", _("Cannot unlock resctrl"));
 
         return -1;
@@ -494,6 +496,29 @@ virResctrlUnlock(int fd)
     return 0;
 }
 
+#else /* WIN32 */
+
+static int
+virResctrlLockWrite(void)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("resctrl locking is not supported "
+                           "on this platform"));
+    return -1;
+}
+
+
+static int
+virResctrlUnlock(int fd G_GNUC_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("resctrl locking is not supported "
+                           "on this platform"));
+    return -1;
+}
+
+#endif /* WIN32 */
+
 
 /* virResctrlInfo-related definitions */
 static int