From: Phil Sutter <phil@nwl.cc>
Date: Thu, 25 Aug 2022 09:53:04 +0000 (+0200)
Subject: xtables-restore: Extend failure error message
X-Git-Tag: v1.8.9~130
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c70a33d219ccb43e6f59aa1b9bbab5dcb13f3443;p=thirdparty%2Fiptables.git

xtables-restore: Extend failure error message

If a line causes zero 'ret' value and errno is set, call nft_strerror()
for a more detailed error message. While not perfect, it helps with
debugging ominous "line NN failed" messages pointing at COMMIT:

| # iptables-nft-restore <<EOF
| *filter
| -A nonexist
| COMMIT
| EOF
| iptables-nft-restore: line 3 failed: No chain/target/match by that name.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---

diff --git a/iptables/xtables-restore.c b/iptables/xtables-restore.c
index 1363f96a..052a80c2 100644
--- a/iptables/xtables-restore.c
+++ b/iptables/xtables-restore.c
@@ -249,8 +249,11 @@ static void xtables_restore_parse_line(struct nft_handle *h,
 	    (strcmp(p->tablename, state->curtable->name) != 0))
 		return;
 	if (!ret) {
-		fprintf(stderr, "%s: line %u failed\n",
+		fprintf(stderr, "%s: line %u failed",
 				xt_params->program_name, line);
+		if (errno)
+			fprintf(stderr,	": %s.", nft_strerror(errno));
+		fprintf(stderr, "\n");
 		exit(1);
 	}
 }