Make lagg creation more fault tolerant

- Warn, don't exit, when SIOCSLAGGPORT returns an error.

When we exit with an error during lagg creation, a single
failed NIC (which no longer attaches) can prevent lagg
creation and other configuration, such as adding an IPv4
address, and thus leave a machine unreachable.

- Preserve non-EEXISTS errors for exit status from SIOCSLAGGPORT,
  in case scripts are looking for it. Hopefully this can be
  extended if other parts of ifconfig can allow a "soft" failure.

- Improve the warning message to mention what lagg and what
  member are problematic.

Reviewed by: jtl, glebius
Sponsored by: Netflix
Differential Revision:	https://reviews.freebsd.org/D15046

1 files changed, 2 insertions, 2 deletions

diff --git a/sbin/ifconfig/ifgroup.c b/sbin/ifconfig/ifgroup.c
index d3792e00a1cb..106d1260ef18 100644
--- a/sbin/ifconfig/ifgroup.c
+++ b/sbin/ifconfig/ifgroup.c
@@ -140,7 +140,7 @@ printgroup(const char *groupname)
 	if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1) {
 		if (errno == EINVAL || errno == ENOTTY ||
 		    errno == ENOENT)
-			exit(0);
+			exit(exit_code);
 		else
 			err(1, "SIOCGIFGMEMB");
 	}
@@ -159,7 +159,7 @@ printgroup(const char *groupname)
 	}
 	free(ifgr.ifgr_groups);
 
-	exit(0);
+	exit(exit_code);
 }
 
 static struct cmd group_cmds[] = {