Re: [libvirt] [PATCH 3/5] Introduce functions for checking whether a pidfile is valid
Eh, I forgot to add some more notes...
...
diff --git a/src/util/virpidfile.c b/src/util/virpidfile.c
index 25c3272..dc92868 100644
--- a/src/util/virpidfile.c
+++ b/src/util/virpidfile.c
@@ -24,6 +24,7 @@
#include <config.h>
#include <fcntl.h>
+#include <signal.h>
#include "virpidfile.h"
#include "virfile.h"
@@ -164,6 +165,63 @@ int virPidFileRead(const char *dir,
}
+int virPidFileReadPathIfAlive(const char *path,
+ pid_t *pid,
+ const char *binpath)
+{
+ int rc;
+ char *procpath = NULL;
+
+ rc = virPidFileReadPath(path, pid);
+ if (rc < 0)
+ return rc;
+
+ /* Check that it's still alive */
+ if (kill(*pid, 0) < 0) {
+ *pid = -1;
+ return 0;
+ }
+
+ if (virAsprintf(&procpath, "/proc/%d/exe", *pid) < 0) {
+ *pid = -1;
+ return 0;
+ }
+#ifdef __linux__
+ if (virFileLinkPointsTo(procpath, binpath) == 0)
+ *pid = -1;
+#endif
+ VIR_FREE(procpath);
Indentation.
And anyway, what about implementing the second half of this function as
follows:
#ifdef __linux__
if (binpath) {
char *procpath = NULL;
if (virAsprintf(&procpath, "/proc/%d/exe", *pid) < 0 ||
!virFileLinkPointsTo(procpath, binpath))
*pid = -1;
VIR_FREE(procpath);
}
#endif
Building procpath makes little sense on non-linux and checking binpath first
allows callers to use *IfAlive for checking pid liveliness without binpath
checks (in case any caller wants to do so) and allows us to move procpath
declaration into the same ifdef block :-)
+
+ return 0;
+}
I think we should also document that both *IfAlive functions return -errno if
the pid file cannot be read or doesn't contain integer value. If it contains a
number but such process is not running or doesn't correspond to binpath, the
return value is 0 but pid is -1.
Jirka