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

[Michal Privoznik]

This reverts commit 938382b60ae5bd1f83b5cb09e1ce68b9a88f679a.

Turns out, the commit did more harm than good. It changed
semantics on some public APIs. For instance, while
qemuDomainGetInfo() previously did not returned an error it does
now. While the calls to virProcessGetStatInfo() is guarded with
virDomainObjIsActive() it doesn't necessarily mean that QEMU's
PID is still alive. QEMU might be gone but we just haven't
realized it (e.g. because the eof handler thread is waiting for a
job).

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2041610
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/ch/ch_driver.c     | 2 ++
 src/qemu/qemu_driver.c | 7 ++++++-
 src/util/virprocess.c  | 8 ++------
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/ch/ch_driver.c b/src/ch/ch_driver.c
index 3cbc668489..53e0872207 100644
--- a/src/ch/ch_driver.c
+++ b/src/ch/ch_driver.c
@@ -1073,6 +1073,8 @@ 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 e150b86cef..373cd62536 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -1357,6 +1357,8 @@ 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;
             }
         }
@@ -2517,6 +2519,8 @@ 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;
         }
     }
@@ -10524,7 +10528,8 @@ qemuDomainMemoryStatsInternal(virQEMUDriver *driver,
     }
 
     if (virProcessGetStatInfo(NULL, NULL, &rss, vm->pid, 0) < 0) {
-        virResetLastError();
+        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
+                       _("cannot get RSS for domain"));
     } 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 85d8c8e747..b559a4257e 100644
--- a/src/util/virprocess.c
+++ b/src/util/virprocess.c
@@ -1784,10 +1784,7 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
         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) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("cannot parse process status data for pid '%d/%d'"),
-                       (int) pid, (int) tid);
-        return -1;
+        VIR_WARN("cannot parse process status data");
     }
 
     /* We got jiffies
@@ -1884,8 +1881,7 @@ virProcessGetStatInfo(unsigned long long *cpuTime G_GNUC_UNUSED,
                       pid_t pid G_GNUC_UNUSED,
                       pid_t tid G_GNUC_UNUSED)
 {
-    virReportSystemError(ENOSYS, "%s",
-                         _("Process statistics data is not supported on this platform"));
+    errno = ENOSYS;
     return -1;
 }
 
-- 
2.34.1