* mountall: make the "console output" Upstart stanza do its work. We

were redirecting output to /var/log/upstart/<job>, so it didn't work
  properly.
* mountall-ip-up: send the USR1 signal to the mountall process by
  looking up its PID, rather than doing "pkill -USR1 mountall".  This
  prevents a very subtle race condition where USR1 is delivered to a
  child process of mountall (such as fsck), if pkill sees the child
  just before its execve().  There is actually still a race condition
  because mountall installs its USR1 handler *after* daemonising, so
  mountall-ip-up could accidentally kill mountall.  Should report this
  to upstream.

svn path=/nixos/trunk/; revision=33236

modules/system/upstart/upstart.nix

@@ -42,8 +42,12 @@ let
 
           ${concatMapStrings (n: "env ${n}=\"${getAttr n env}\"\n") (attrNames env)}
 
+          ${optionalString (job.console != "") "console ${job.console}"}
+
           pre-start script
-            exec >> ${log} 2>&1
+            ${optionalString (job.console == "") ''
+              exec >> ${log} 2>&1
+            ''}
             ln -sfn "$(readlink -f "/etc/init/${job.name}.conf")" /var/run/upstart-jobs/${job.name}
             ${optionalString (job.preStart != "") ''
               source ${jobHelpers}
@@ -56,24 +60,32 @@ let
             else if job.script != "" then
               ''
                 script
-                  exec >> ${log} 2>&1
+                  ${optionalString (job.console == "") ''
+                    exec >> ${log} 2>&1
+                  ''}
                   source ${jobHelpers}
                   ${job.script}
                 end script
               ''
-            else if job.exec != "" then
+            else if job.exec != "" && job.console == "" then
               ''
                 script
                   exec >> ${log} 2>&1
                   exec ${job.exec}
                 end script
               ''
+            else if job.exec != "" then
+              ''
+                exec ${job.exec}
+              ''
             else ""
           }
 
           ${optionalString (job.postStart != "") ''
             post-start script
-              exec >> ${log} 2>&1
+              ${optionalString (job.console == "") ''
+                exec >> ${log} 2>&1
+              ''}
               source ${jobHelpers}
               ${job.postStart}
             end script
@@ -88,7 +100,9 @@ let
              # (upstart 0.6.5, job.c:562)
             optionalString (job.preStop != "") (assert hasMain; ''
             pre-stop script
-              exec >> ${log} 2>&1
+              ${optionalString (job.console == "") ''
+                exec >> ${log} 2>&1
+              ''}
               source ${jobHelpers}
               ${job.preStop}
             end script
@@ -96,7 +110,9 @@ let
 
           ${optionalString (job.postStop != "") ''
             post-stop script
-              exec >> ${log} 2>&1
+              ${optionalString (job.console == "") ''
+                exec >> ${log} 2>&1
+              ''}
               source ${jobHelpers}
               ${job.postStop}
             end script
@@ -364,6 +380,18 @@ let
       '';
     };
 
+    console = mkOption {
+      default = "";
+      example = "console";
+      description = ''
+        If set to <literal>output</literal>, job output is written to
+        the console.  If it's <literal>owner</literal>, additionally
+        the job becomes owner of the console.  It it's empty (the
+        default), output is written to
+        <filename>/var/log/upstart/<replaceable>jobname</replaceable></filename>
+      '';  
+    };
+
   };
 
 

modules/tasks/filesystems.nix

@@ -178,7 +178,9 @@ in
 
         path = [ pkgs.utillinux pkgs.mountall ] ++ config.system.fsPackages;
 
-        script =
+        console = "output";
+
+        preStart =
           ''
             # Ensure that this job is restarted when fstab changed:
             # ${fstab}
@@ -186,11 +188,13 @@ in
             ${optionalString config.services.nfs.client.enable ''
               ensure statd || true
             ''}
-            
-            exec > /dev/console 2>&1
+
             echo "mounting filesystems..."
-            exec mountall
           '';
+
+        daemonType = "daemon";
+          
+        exec = "mountall --daemon";
       };
 
     # The `mount-failed' event is emitted synchronously, but we don't
@@ -223,19 +227,26 @@ in
         startOn = "ip-up";
         script =
           ''
-            ${pkgs.procps}/bin/pkill -USR1 -u root mountall || true
+            # Send USR1 to the mountall process.  Can't use "pkill
+            # mountall" here because that has a race condition: we may
+            # accidentally send USR1 to children of mountall (such as
+            # fsck) just before they do execve().
+            status="$(status mountall)"
+            if [[ "$status" =~ "start/running, process "([0-9]+) ]]; then
+                pid=''${BASH_REMATCH[1]}
+                echo "sending USR1 to $pid..."
+                kill -USR1 "$pid"
+            fi
           '';
       };
 
     jobs."emergency-shell" =
       { task = true;
 
-        extraConfig = "console owner";
+        console = "owner";
 
         script =
           ''
-            exec < /dev/console > /dev/console 2>&1
-
             cat <<EOF
 
             <<< Emergency shell >>>