On Mon, Nov 22, 2021 at 10:34:38AM +0100, Martin Kletzander wrote:
> On Mon, Nov 22, 2021 at 09:18:41AM +0000, Daniel P. Berrangé wrote:
> > 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 ?
> >
>
> One of the implementations was just looking for first closing
> parenthesis to find the end of the command name, which should be done by
> looking at the _last_ closing parenthesis. This might fail in a very
> small corner case which is tested for in the first patch. But you are
> right, I should add this to the commit message. Will do in v3.
>
> > >
> > > Signed-off-by: Martin Kletzander <mkletzan@xxxxxxxxxx>
> > > ---
> > > 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
> >
>
> I was thinking about that and also tried figuring out how to encode the
> proper field types in the header file. But since we are not doing lot
> of /proc/*/stat parsing in our codebase I though that would be an
> overkill. I'll add at least the constants.
BTW ,didn't mean we need constants for all 40+ fields - just the ones
we actually use.
Regards,
Daniel
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