[padb-devel] [padb] r214 committed - Guard against errors if the target process dies whilst we are initiali...

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Revision: 214
Author: apittman
Date: Tue Sep  8 13:03:00 2009
Log: Guard against errors if the target process dies whilst we are  
initialising, check the return code of
all calls to query it's status and ignore it completely if it disappears.   
This removes a number of
errors when the process dies.

http://code.google.com/p/padb/source/detail?r=214

Modified:
  /branches/cleanup/src/padb

=======================================
--- /branches/cleanup/src/padb	Tue Sep  8 12:39:08 2009
+++ /branches/cleanup/src/padb	Tue Sep  8 13:03:00 2009
@@ -6648,6 +6648,19 @@
      }
      return;
  }
+
+sub hash_from_status {
+    my ($pid) = @_;
+    my %status;
+    my @pairs = slurp_file("/proc/$pid/status");
+    return unless @pairs;
+    foreach my $pair (@pairs) {
+        if ( $pair =~ m{\A(\w+):\s*(.+)}x ) {
+            $status{$1} = $2;
+        }
+    }
+    return \%status;
+}

  sub is_resmgr_process {
      my $pid  = shift;
@@ -6947,7 +6960,13 @@

          next unless defined $rmpid;

-        if ( defined $scripts{ pid_to_name($pid) } ) {
+        # Handle with the process going away whilst we look here,
+        # if we don't have a name then it's gone and we should
+        # continue without it.
+        my $name = pid_to_name($pid);
+        next unless defined $name;
+
+        if ( defined $scripts{$name} ) {
              push @{ $ipids->{$rmpid}{scripts} }, $pid;
          } else {
              push @{ $ipids->{$rmpid}{notscripts} }, $pid;
@@ -6976,13 +6995,17 @@
          # The process might have died and we simply didn't find anything,
          # if this is the case then just skip it, the outer will notice
          # the missing signon and report an approtiate error.
-        if ( defined $newpid ) {
-            push @apids,
-              {
-                pid => $newpid,
-                vp  => $ip->{rank}
-              };
-        }
+        next unless defined $newpid;
+
+        my $status = hash_from_status($newpid);
+        next unless defined $status;
+        push @apids,
+          {
+            pid    => $newpid,
+            vp     => $ip->{rank},
+            status => $status,
+          };
+
      }

      # Sort local pids by order of increasing rank.
@@ -7006,13 +7029,11 @@
      convert_pids_to_child_pids();

      foreach my $proc ( @{ $confInner{all_pids} } ) {
-        my $pid   = $proc->{pid};
-        my $vp    = $proc->{vp};
-        my $name  = readlink("/proc/$pid/exe");
-        my $state = find_from_status( $pid, 'State' );
+        my $pid  = $proc->{pid};
+        my $vp   = $proc->{vp};
          target_key_pair( $vp, 'found', 'yes' );
-        target_key_pair( $vp, 'name',  $name );
-        target_key_pair( $vp, 'state', $state );
+        target_key_pair( $vp, 'name',  $proc->{status}->{Name} );
+        target_key_pair( $vp, 'state', $proc->{status}->{State} );
      }
      return;
  }
@@ -7095,8 +7116,7 @@
          # Loop over ranks first as there are potentially more of them.
          while ( defined( my $rank = rng_shift($rng) ) ) {
              foreach my $proc ( @{ $confInner{all_pids} } ) {
-                my $vp  = $proc->{vp};
-                my $pid = $proc->{pid};
+                my $vp = $proc->{vp};
                  if ( $vp == $rank ) {
                      push @{$pid_list}, $proc;
                  }