[PATCH v4] report error when virProcessGetStatInfo() is unable to parse data

[Ani Sinha]

I just realized after sending this patch that I made the change in the
Linux version of the function. It may not be applicable for FreeBSD .
In any case I simply don’t understand if errors on the logs is a problem.
If it is maybe we need a FreeBSD version of this function as well not just
a larger bucket on non Linux flavours that report error .

On Tue, Jan 11, 2022 at 23:43 Ani Sinha <ani at anisinha.ca> wrote:

> Currently virProcessGetStatInfo() always returns success and only logs
> error
> when it is unable to parse the data. Make this function actually report the
> error and return a negative value in this error scenario.
>
> Fix the callers so that they do not override the error generated.
> Also fix non-linux implementation of this function so as to report error.
>
> Signed-off-by: Ani Sinha <ani at anisinha.ca>
> ---
>  src/ch/ch_driver.c     |  2 --
>  src/qemu/qemu_driver.c |  7 +------
>  src/util/virprocess.c  | 17 +++++++++++++----
>  3 files changed, 14 insertions(+), 12 deletions(-)
>
> changelog:
> v4: on freebsd error on the logs is a problem appaently. try to fix
> that.
> v3: fix non linux implementation
> v2: fix callers
>
> diff --git a/src/ch/ch_driver.c b/src/ch/ch_driver.c
> index 53e0872207..3cbc668489 100644
> --- a/src/ch/ch_driver.c
> +++ b/src/ch/ch_driver.c
> @@ -1073,8 +1073,6 @@ chDomainHelperGetVcpus(virDomainObj *vm,
>              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
>                                        &vcpuinfo->cpu, NULL,
>                                        vm->pid, vcpupid) < 0) {
> -                virReportSystemError(errno, "%s",
> -                                      _("cannot get vCPU placement & pCPU
> time"));
>                  return -1;
>              }
>          }
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index d3d76c003f..65ac5ef367 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -1359,8 +1359,6 @@ qemuDomainHelperGetVcpus(virDomainObj *vm,
>              if (virProcessGetStatInfo(&vcpuinfo->cpuTime,
>                                        &vcpuinfo->cpu, NULL,
>                                        vm->pid, vcpupid) < 0) {
> -                virReportSystemError(errno, "%s",
> -                                     _("cannot get vCPU placement & pCPU
> time"));
>                  return -1;
>              }
>          }
> @@ -2521,8 +2519,6 @@ qemuDomainGetInfo(virDomainPtr dom,
>      if (virDomainObjIsActive(vm)) {
>          if (virProcessGetStatInfo(&(info->cpuTime), NULL, NULL,
>                                    vm->pid, 0) < 0) {
> -            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> -                           _("cannot read cputime for domain"));
>              goto cleanup;
>          }
>      }
> @@ -10530,8 +10526,7 @@ qemuDomainMemoryStatsInternal(virQEMUDriver
> *driver,
>      }
>
>      if (virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0) < 0) {
> -        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> -                       _("cannot get RSS for domain"));
> +        virResetLastError();
>      } else {
>          stats[ret].tag = VIR_DOMAIN_MEMORY_STAT_RSS;
>          stats[ret].val = rss;
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index b559a4257e..cbb31441cc 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -1779,12 +1779,20 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
>      long rss = 0;
>      int cpu = 0;
>
> -    if (!proc_stat ||
> -        virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10,
> &usertime) < 0 ||
> +    if (!proc_stat) {
> +        VIR_WARN("Unable to get proc stats from the kernel");
> +        return 0;
> +    }
> +
> +    if (virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_UTIME], NULL, 10,
> &usertime) < 0 ||
>          virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10,
> &systime) < 0 ||
>          virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) <
> 0 ||
>          virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10,
> &cpu) < 0) {
> -        VIR_WARN("cannot parse process status data");
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("cannot parse process status data for pid
> '%d/%d'"),
> +                       (int) pid, (int) tid);
> +
> +        return -1;
>      }
>
>      /* We got jiffies
> @@ -1881,7 +1889,8 @@ virProcessGetStatInfo(unsigned long long *cpuTime
> G_GNUC_UNUSED,
>                        pid_t pid G_GNUC_UNUSED,
>                        pid_t tid G_GNUC_UNUSED)
>  {
> -    errno = ENOSYS;
> +    virReportSystemError(ENOSYS, "%s",
> +                         _("Process statistics data is not supported on
> this platform"));
>      return -1;
>  }
>
> --
> 2.25.1
>
>
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