Re: [PATCH v3 1/3] virpidfile: Add virPidFileReadPathIfLocked func

The function will attempt to read a pid from @path, and store it in @pid. The @pid will only be set, however, if @path is locked by virFileLock() at byte 0 and the pid in @path is running. Signed-off-by: Vasiliy Ulyanov <vulyanov(a)suse.de&gt; --- src/libvirt_private.syms | 1 + src/util/virpidfile.c | 34 ++++++++++++++++++++++++++++++++++ src/util/virpidfile.h | 2 ++ 3 files changed, 37 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 9bc3d9530b..447ba9d82b 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -3070,6 +3070,7 @@ virPidFileRead; virPidFileReadIfAlive; virPidFileReadPath; virPidFileReadPathIfAlive; +virPidFileReadPathIfLocked; virPidFileRelease; virPidFileReleasePath; virPidFileWrite; diff --git a/src/util/virpidfile.c b/src/util/virpidfile.c index 7069f8343d..b8bb455e5e 100644 --- a/src/util/virpidfile.c +++ b/src/util/virpidfile.c @@ -302,6 +302,40 @@ int virPidFileReadIfAlive(const char *dir, return 0; } +/** + * virPidFileReadPathIfLocked: + * @path: path to pidfile + * @pid: variable to return pid in + * + * This will attempt to read a pid from @path, and store it + * in @pid. The @pid will only be set, however, if the + * pid in @path is running, and @path is locked by virFileLock() + * at byte 0. This adds protection against returning a stale pid.