daemon: Always reflect command stderr to stderr when debugging.

When debugging (ie. LIBGUESTFS_DEBUG=1 & verbose flag set in daemon)
always reflect any stderr output from commands that we run to
stderr of the daemon, so it is visible.

Previously if stderror == NULL in command*, stderr output was
just eaten and discarded which meant useful error messages could
be lost.

1 files changed, 16 insertions, 9 deletions

diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index bf06c73d..370eea8d 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -38,6 +38,8 @@
 #include <printf.h>
 
 #include "c-ctype.h"
+#include "ignore-value.h"
+
 #include "daemon.h"
 
 static char *read_cmdline (void);
@@ -742,15 +744,20 @@ commandrvf (char **stdoutput, char **stderror, int flags,
       }
       if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
 
-      if (r > 0 && stderror) {
-        se_size += r;
-        p = realloc (*stderror, se_size);
-        if (p == NULL) {
-          perror ("realloc");
-          goto quit;
-        }
-        *stderror = p;
-        memcpy (*stderror + se_size - r, buf, r);
+      if (r > 0) {
+	if (verbose)
+	  ignore_value (write (2, buf, r));
+
+	if (stderror) {
+	  se_size += r;
+	  p = realloc (*stderror, se_size);
+	  if (p == NULL) {
+	    perror ("realloc");
+	    goto quit;
+	  }
+	  *stderror = p;
+	  memcpy (*stderror + se_size - r, buf, r);
+	}
       }
     }
   }