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. Thanks, Martin
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 :|
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