Re: [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&gt; Reviewed-by: Andrea Bolognani <abologna(a)redhat.com&gt; --- 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