[PATCH v2] pasta: propagate exit code from child command

[Paul Holzinger <pholzing@redhat.com>]

Exits codes are very useful for scripts, when the pasta child execvp()
call fails with ENOENT that parent should also exit with > 0. In short
the parent should always exit with the code from the child to make it
useful in scripts.

It is easy to test with: `pasta -- bash -c "exit 3"; echo $?`

Signed-off-by: Paul Holzinger <pholzing@redhat.com>
---
Changes from v1:
 - Fixed comments from Stefano.

 pasta.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/pasta.c b/pasta.c
index 3f6477c..fe21c5b 100644
--- a/pasta.c
+++ b/pasta.c
@@ -64,9 +64,17 @@ void pasta_child_handler(int signal)
 
 	if (pasta_child_pid &&
 	    !waitid(P_PID, pasta_child_pid, &infop, WEXITED | WNOHANG)) {
-		if (infop.si_pid == pasta_child_pid)
-			exit(EXIT_SUCCESS);
+		if (infop.si_pid == pasta_child_pid) {
+			if (infop.si_code == CLD_EXITED)
+				exit(infop.si_status);
+
+			/* If killed by a signal, si_status is the number.
+			 * Follow common shell convention of returning it + 128.
+			 */
+			exit(infop.si_status + 128);
+
 			/* Nothing to do, detached PID namespace going away */
+		}
 	}
 
 	waitid(P_ALL, 0, NULL, WEXITED | WNOHANG);
-- 
@@ -64,9 +64,17 @@ void pasta_child_handler(int signal)
 
 	if (pasta_child_pid &&
 	    !waitid(P_PID, pasta_child_pid, &infop, WEXITED | WNOHANG)) {
-		if (infop.si_pid == pasta_child_pid)
-			exit(EXIT_SUCCESS);
+		if (infop.si_pid == pasta_child_pid) {
+			if (infop.si_code == CLD_EXITED)
+				exit(infop.si_status);
+
+			/* If killed by a signal, si_status is the number.
+			 * Follow common shell convention of returning it + 128.
+			 */
+			exit(infop.si_status + 128);
+
 			/* Nothing to do, detached PID namespace going away */
+		}
 	}
 
 	waitid(P_ALL, 0, NULL, WEXITED | WNOHANG);
-- 
2.39.1