[PATCH v2 1/2] util: Rework virFileFlock() to be unambiguous
The boolean parameters for lock/unlock and read/write (shared/exclusive) caused
a lot of confusion when reading the callers. The new approach is explicit and
unambiguous.
Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com>
Reviewed-by: Andrea Bolognani <abologna(a)redhat.com>
---
src/util/virfile.c | 27 ++++++++++++++++++---------
src/util/virfile.h | 9 ++++++++-
src/util/virresctrl.c | 4 ++--
3 files changed, 28 insertions(+), 12 deletions(-)
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 213acdbcaa2b..554011eecb25 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -465,23 +465,33 @@ 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`
+ * @op: operation to perform
*
* 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`.
+ * `@op == VIR_FILE_FLOCK_UNLOCK`.
*
* Returns 0 on success, -1 otherwise (with errno set)
*/
-int virFileFlock(int fd, bool lock, bool shared)
+int virFileFlock(int fd, virFileFlockOperation op)
{
- if (lock)
- return flock(fd, shared ? LOCK_SH : LOCK_EX);
+ int flock_op = -1;
- return flock(fd, LOCK_UN);
+ switch (op) {
+ case VIR_FILE_FLOCK_SHARED:
+ flock_op = LOCK_SH;
+ break;
+ case VIR_FILE_FLOCK_EXCLUSIVE:
+ flock_op = LOCK_EX;
+ break;
+ case VIR_FILE_FLOCK_UNLOCK:
+ flock_op = LOCK_UN;
+ break;
+ }
+
+ return flock(fd, flock_op);
}
#else /* WIN32 */
@@ -505,8 +515,7 @@ int virFileUnlock(int fd G_GNUC_UNUSED,
int virFileFlock(int fd G_GNUC_UNUSED,
- bool lock G_GNUC_UNUSED,
- bool shared G_GNUC_UNUSED)
+ virFileFlockOperation op G_GNUC_UNUSED)
{
errno = ENOSYS;
return -1;
diff --git a/src/util/virfile.h b/src/util/virfile.h
index 7a92364a5c9f..04428727fd3b 100644
--- a/src/util/virfile.h
+++ b/src/util/virfile.h
@@ -118,7 +118,14 @@ 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 enum {
+ VIR_FILE_FLOCK_EXCLUSIVE,
+ VIR_FILE_FLOCK_SHARED,
+ VIR_FILE_FLOCK_UNLOCK,
+} virFileFlockOperation;
+
+int virFileFlock(int fd, virFileFlockOperation op);
typedef int (*virFileRewriteFunc)(int fd, const void *opaque);
int virFileRewrite(const char *path,
diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c
index 3563fc560db5..b685b8bb6f7b 100644
--- a/src/util/virresctrl.c
+++ b/src/util/virresctrl.c
@@ -463,7 +463,7 @@ virResctrlLockWrite(void)
return -1;
}
- if (virFileFlock(fd, true, true) < 0) {
+ if (virFileFlock(fd, VIR_FILE_FLOCK_SHARED) < 0) {
virReportSystemError(errno, "%s", _("Cannot lock resctrl"));
VIR_FORCE_CLOSE(fd);
return -1;
@@ -485,7 +485,7 @@ virResctrlUnlock(int fd)
virReportSystemError(errno, "%s", _("Cannot close
resctrl"));
/* Trying to save the already broken */
- if (virFileFlock(fd, false, false) < 0)
+ if (virFileFlock(fd, VIR_FILE_FLOCK_UNLOCK) < 0)
virReportSystemError(errno, "%s", _("Cannot unlock
resctrl"));
return -1;
--
2.27.0