Add a routine to format error messages with an errno-based message at the end.

That routine will use strerror_s() or strerror_r() if available, in a
fashion that's thread-safe.  Otherwise, it falls back on
pcap_strerror().

Use it in both libpcap and rpcapd.

Given that we check for errors in strerror_r(), hopefully this will
squelch warnings with newer version of GCC and GNU libc; whilst the
macOS (and other BSD-flavored?) strerror_r() always fills in a message,
that's not required by the Single UNIX Specification, as far as I can
tell, so we apparently really *do* need to check for errors.

1 files changed, 3 insertions, 2 deletions

diff --git a/dlpisubs.c b/dlpisubs.c
index cd85a404..4520a31e 100644
--- a/dlpisubs.c
+++ b/dlpisubs.c
@@ -358,7 +358,8 @@ pcap_alloc_databuf(pcap_t *p)
 	p->bufsize = PKTBUFSIZE;
 	p->buffer = malloc(p->bufsize + p->offset);
 	if (p->buffer == NULL) {
-		strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
+		pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+		    errno, "");
 		return (-1);
 	}
 
@@ -392,6 +393,6 @@ strioctl(int fd, int cmd, int len, char *dp)
 static void
 pcap_stream_err(const char *func, int err, char *errbuf)
 {
-	pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", func, pcap_strerror(err));
+	pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, err, "%s", func);
 }
 #endif