From 75d4ed800f297532a7b3ac2b8f8a94c049959e3b Mon Sep 17 00:00:00 2001
From: Michal Privoznik <[email protected]>
Date: Fri, 18 Dec 2020 16:09:08 +0100
Subject: [PATCH 024/108] leaseshelper: Report errors on failure
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

If leasehelper fails all that we are left with is a simple error
message produced by dnsmasq:

  lease-init script returned exit code 1

This is because the leasehelper did not write any message to
stderr. According to dnsmasq's manpage, whenever it's invoking
leasehelper the stderr is kept open:

  All file descriptors are closed except stdin, which is open to
  /dev/null, and stdout and stderr which capture output for
  logging by dnsmasq.

As debugging leasehelper is not trivial (because dnsmasq invokes
it with plenty of env vars set - that's how data is passed onto
helper), let's print an error into stderr if exiting with an
error. And since we are not calling public APIs, we have to call
virDispatchError() explicitly and since we don't have any
connection open, we have to pass NULL.

Signed-off-by: Michal Privoznik <[email protected]>
Reviewed-by: Daniel P. Berrangé <[email protected]>
(cherry picked from commit c14bd64f3eba9838af8ab1cac369d51abfeb21b9)
---
 src/network/leaseshelper.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/network/leaseshelper.c b/src/network/leaseshelper.c
index 2b5fc0f442..fdd7fd3e80 100644
--- a/src/network/leaseshelper.c
+++ b/src/network/leaseshelper.c
@@ -253,6 +253,8 @@ main(int argc, char **argv)
     rv = EXIT_SUCCESS;
 
  cleanup:
+    if (rv != EXIT_SUCCESS)
+        virDispatchError(NULL);
     if (pid_file_fd != -1)
         virPidFileReleasePath(pid_file, pid_file_fd);
 
-- 
2.33.0