Do the right check for "no name resolution information to save".

The check that the pcapng code does is "do we have a non-null
addrinfo_lists_t * and, if so, does it have a non-null ipv4_addr_list or
ipv6_addr_list"?

The check that the file-save code was using was just "do we have a
non-null addrinfo_lists_t *", so sometimes it'd think we couldn't do a
"quick save" even though we had no name resolution information to write
out to the capture file.

Make a routine that does that check, and use it in *both* places.

Change-Id: Id4720f4fe4940354320b2b7621ca5e37e45ec1f3
Reviewed-on: https://code.wireshark.org/review/25055
Reviewed-by: Guy Harris <guy@alum.mit.edu>

4 files changed, 17 insertions, 6 deletions

diff --git a/file.c b/file.c
index 8dc9679d44..6023e539d2 100644
--- a/file.c
+++ b/file.c
@@ -4284,11 +4284,12 @@ cf_save_records(capture_file *cf, const char *fname, guint save_format,
 
   if (save_format == cf->cd_t && compressed == cf->iscompressed
       && !discard_comments && !cf->unsaved_changes
-      && !(addr_lists && wtap_dump_has_name_resolution(save_format))) {
-    /* We're saving in the format it's already in, and we're
-       not discarding comments, and there are no changes we have
-       in memory that aren't saved to the file, and we have no name
-       resolution blocks to write, so we can just move or copy the raw data. */
+      && (wtap_addrinfo_list_empty(addr_lists) || !wtap_dump_has_name_resolution(save_format))) {
+    /* We're saving in the format it's already in, and we're not discarding
+       comments, and there are no changes we have in memory that aren't saved
+       to the file, and we have no name resolution information to write or
+       the file format we're saving in doesn't support writing name
+       resolution information, so we can just move or copy the raw data. */
 
     if (cf->is_tempfile) {
       /* The file being saved is a temporary file from a live
diff --git a/wiretap/file_access.c b/wiretap/file_access.c
index 8740756df2..307fa17e55 100644
--- a/wiretap/file_access.c
+++ b/wiretap/file_access.c
@@ -2608,6 +2608,14 @@ wtap_set_bytes_dumped(wtap_dumper *wdh, gint64 bytes_dumped)
 }
 
 gboolean
+wtap_addrinfo_list_empty(addrinfo_lists_t *addrinfo_lists)
+{
+	return (addrinfo_lists == NULL) ||
+	    ((addrinfo_lists->ipv4_addr_list == NULL) &&
+	     (addrinfo_lists->ipv6_addr_list == NULL));
+}
+
+gboolean
 wtap_dump_set_addrinfo_list(wtap_dumper *wdh, addrinfo_lists_t *addrinfo_lists)
 {
 	if (!wdh || wdh->file_type_subtype < 0 || wdh->file_type_subtype >= wtap_num_file_types_subtypes
diff --git a/wiretap/pcapng.c b/wiretap/pcapng.c
index 9217781341..6d82f42a7d 100644
--- a/wiretap/pcapng.c
+++ b/wiretap/pcapng.c
@@ -3376,7 +3376,7 @@ pcapng_write_name_resolution_block(wtap_dumper *wdh, int *err)
     hashipv6_t *ipv6_hash_list_entry;
     int i;
 
-    if ((!wdh->addrinfo_lists) || ((!wdh->addrinfo_lists->ipv4_addr_list)&&(!wdh->addrinfo_lists->ipv6_addr_list))) {
+    if (wtap_addrinfo_list_empty(wdh->addrinfo_lists)) {
         /*
          * No name/address pairs to write.
          * XXX - what if we have options?
diff --git a/wiretap/wtap.h b/wiretap/wtap.h
index 5c3fece007..dbbaf83667 100644
--- a/wiretap/wtap.h
+++ b/wiretap/wtap.h
@@ -1932,6 +1932,8 @@ WS_DLL_PUBLIC
 void wtap_set_bytes_dumped(wtap_dumper *wdh, gint64 bytes_dumped);
 struct addrinfo;
 WS_DLL_PUBLIC
+gboolean wtap_addrinfo_list_empty(addrinfo_lists_t *addrinfo_lists);
+WS_DLL_PUBLIC
 gboolean wtap_dump_set_addrinfo_list(wtap_dumper *wdh, addrinfo_lists_t *addrinfo_lists);
 WS_DLL_PUBLIC
 gboolean wtap_dump_get_needs_reload(wtap_dumper *wdh);