bpf: in check_setif_failure(), refer to the error code we were passed.

In some places, we referred to "errno" rather than "error"; the latter
is the error code we were passed and which we should check and use in
error messages.

In addition, don't set p->errbuf for ENXIO - that's just "No such
device", and we already return an error code for that - a string saying
BIOCSETIF failed with "Device not configured" adds no useful information
to the one you get for PCAP_ERROR_NO_SUCH_DEVICE.

1 files changed, 2 insertions, 4 deletions

diff --git a/pcap-bpf.c b/pcap-bpf.c
index 1c4e6110..fe4d78c1 100644
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -1588,10 +1588,8 @@ check_setif_failure(pcap_t *p, int error)
 		/*
 		 * No such device.
 		 */
-		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
-		    errno, "BIOCSETIF failed");
 		return (PCAP_ERROR_NO_SUCH_DEVICE);
-	} else if (errno == ENETDOWN) {
+	} else if (error == ENETDOWN) {
 		/*
 		 * Return a "network down" indication, so that
 		 * the application can report that rather than
@@ -1606,7 +1604,7 @@ check_setif_failure(pcap_t *p, int error)
 		 * return PCAP_ERROR.
 		 */
 		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
-		    errno, "BIOCSETIF: %s", p->opt.device);
+		    error, "BIOCSETIF: %s", p->opt.device);
 		return (PCAP_ERROR);
 	}
 }