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

[Ani Sinha]

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