util: make it easier to grab only regular process exit

Right now, a caller waiting for a child process either requires
the child to have status 0, or must use WIFEXITED() and friends
itself.  But in many cases, we want the middle ground of treating
fatal signals as an error, and directly accessing the normal exit
value without having to use WEXITSTATUS(), in order to easily
detect an expected non-zero exit status.  This adds the middle
ground to the low-level virProcessWait; the next patch will add
it to virCommand.

* src/util/virprocess.h (virProcessWait): Alter signature.
* src/util/virprocess.c (virProcessWait): Add parameter.
(virProcessRunInMountNamespace): Adjust caller.
* src/util/vircommand.c (virCommandWait): Likewise.
* src/util/virfile.c (virFileAccessibleAs): Likewise.
* src/lxc/lxc_container.c (lxcContainerHasReboot)
(lxcContainerAvailable): Likewise.
* daemon/libvirtd.c (daemonForkIntoBackground): Likewise.
* tools/virt-login-shell.c (main): Likewise.
* tools/virsh-domain.c (cmdLxcEnterNamespace): Likewise.
* tests/testutils.c (virtTestCaptureProgramOutput): Likewise.
* tests/commandtest.c (test23): Likewise.

Signed-off-by: Eric Blake <eblake@redhat.com>

tools/virsh-domain.c

@@ -8206,7 +8206,7 @@ cmdLxcEnterNamespace(vshControl *ctl, const vshCmd *cmd)
             execv(cmdargv[0], cmdargv);
             _exit(255);
         } else {
-            if (virProcessWait(pid, NULL) < 0)
+            if (virProcessWait(pid, NULL, false) < 0)
                 _exit(255);
         }
         _exit(0);
@@ -8214,7 +8214,7 @@ cmdLxcEnterNamespace(vshControl *ctl, const vshCmd *cmd)
         for (i = 0; i < nfdlist; i++)
             VIR_FORCE_CLOSE(fdlist[i]);
         VIR_FREE(fdlist);
-        if (virProcessWait(pid, NULL) < 0)
+        if (virProcessWait(pid, NULL, false) < 0)
             goto cleanup;
     }
 

tools/virt-login-shell.c

@@ -369,9 +369,9 @@ main(int argc, char **argv)
                 return EXIT_FAILURE;
             }
         }
-        return virProcessWait(ccpid, &status2);
+        return virProcessWait(ccpid, &status2, true);
     }
-    ret = virProcessWait(cpid, &status);
+    ret = virProcessWait(cpid, &status, true);
 
 cleanup:
     virConfFree(conf);