Re: [PATCH v2 2/2] Use virProcessGetStat

On Sun, Nov 21, 2021 at 12:04:26AM +0100, Martin Kletzander wrote: > This eliminates one incorrect parsing implementation. Please explain what was being done wrongly / what was the effect of the bug ?

> > Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com&gt; > --- > src/qemu/qemu_driver.c | 33 ++++++----------------------- > src/util/virprocess.c | 48 ++++++------------------------------------ > 2 files changed, 12 insertions(+), 69 deletions(-) > > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c > index d954635dde2a..0468d6aaf314 100644 > --- a/src/qemu/qemu_driver.c > +++ b/src/qemu/qemu_driver.c > @@ -1399,36 +1399,17 @@ qemuGetSchedInfo(unsigned long long *cpuWait, > > static int > qemuGetProcessInfo(unsigned long long *cpuTime, int *lastCpu, long *vm_rss, > - pid_t pid, int tid) > + pid_t pid, pid_t tid) > { > - g_autofree char *proc = NULL; > - FILE *pidinfo; > + g_auto(GStrv) proc_stat = virProcessGetStat(pid, tid); > unsigned long long usertime = 0, systime = 0; > long rss = 0; > int cpu = 0; > > - /* In general, we cannot assume pid_t fits in int; but /proc parsing > - * is specific to Linux where int works fine. */ > - if (tid) > - proc = g_strdup_printf("/proc/%d/task/%d/stat", (int)pid, tid); > - else > - proc = g_strdup_printf("/proc/%d/stat", (int)pid); > - if (!proc) > - return -1; > - > - pidinfo = fopen(proc, "r"); > - > - /* See 'man proc' for information about what all these fields are. We're > - * only interested in a very few of them */ > - if (!pidinfo || > - fscanf(pidinfo, > - /* pid -> stime */ > - "%*d (%*[^)]) %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %llu %llu" > - /* cutime -> endcode */ > - "%*d %*d %*d %*d %*d %*d %*u %*u %ld %*u %*u %*u" > - /* startstack -> processor */ > - "%*u %*u %*u %*u %*u %*u %*u %*u %*u %*u %*d %d", > - &usertime, &systime, &rss, &cpu) != 4) { > + if (virStrToLong_ullp(proc_stat[13], NULL, 10, &usertime) < 0 || > + virStrToLong_ullp(proc_stat[14], NULL, 10, &systime) < 0 || > + virStrToLong_l(proc_stat[23], NULL, 10, &rss) < 0 || > + virStrToLong_i(proc_stat[38], NULL, 10, &cpu) < 0) { Since you're adding a formal API, I think we'd benefit from constants for these array indexes in virprocess.h

Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|