Clean up handling of --capture-comment.

Don't store the comments in a capture_options structure, because that's
available only if we're being built with capture support, and
--capture-comment can be used in TShark when reading a capture file and
writing another capture file, with no live capture taking place.

This means we don't handle that option in capture_opts_add_opt(); handle
it in the programs that support it.

Support writing multiple comments in dumpcap when capturing.

These changes also fix builds without pcap, and makes --capture-comment
work in Wireshark when a capture is started from the command line with
-k.

Update the help messages to indicate that --capture-comment adds a
capture comment, it doesn't change any comment (much less "the" comment,
as there isn't necessarily a single comment).

Update the man pages:

- not to presume that only pcapng files support file comments (even if
that's true now, it might not be true in the future);
- to note that multiple instances of --capture-comment are supported,
and that multiple comments will be written, whether capturing or reading
one file and writing another;
- clarify that Wireshark doesn't *discard* SHB comments other than the
first one, even though it only displays the first one;

1 files changed, 15 insertions, 6 deletions

diff --git a/writecap/pcapio.c b/writecap/pcapio.c
index 14e4d7f31b..124531de9c 100644
--- a/writecap/pcapio.c
+++ b/writecap/pcapio.c
@@ -307,7 +307,7 @@ pcapng_write_block(FILE* pfile,
 
 gboolean
 pcapng_write_section_header_block(FILE* pfile,
-                                  const char *comment,
+                                  GPtrArray *comments,
                                   const char *hw,
                                   const char *os,
                                   const char *appname,
@@ -324,13 +324,17 @@ pcapng_write_section_header_block(FILE* pfile,
         block_total_length = sizeof(struct shb) +
                              sizeof(guint32);
         options_length = 0;
-        options_length += pcapng_count_string_option(comment);
+        if (comments != NULL) {
+          for (guint i = 0; i < comments->len; i++) {
+            options_length += pcapng_count_string_option((char *)g_ptr_array_index(comments, i));
+          }
+        }
         options_length += pcapng_count_string_option(hw);
         options_length += pcapng_count_string_option(os);
         options_length += pcapng_count_string_option(appname);
         /* If we have options add size of end-of-options */
         if (options_length != 0) {
-                options_length += (guint32)sizeof(struct option);
+          options_length += (guint32)sizeof(struct option);
         }
         block_total_length += options_length;
 
@@ -345,9 +349,14 @@ pcapng_write_section_header_block(FILE* pfile,
         if (!write_to_file(pfile, (const guint8*)&shb, sizeof(struct shb), bytes_written, err))
                 return FALSE;
 
-        if (!pcapng_write_string_option(pfile, OPT_COMMENT, comment,
-                                        bytes_written, err))
-                return FALSE;
+        if (comments != NULL) {
+          for (guint i = 0; i < comments->len; i++) {
+            if (!pcapng_write_string_option(pfile, OPT_COMMENT,
+                                            (char *)g_ptr_array_index(comments, i),
+                                            bytes_written, err))
+                    return FALSE;
+          }
+        }
         if (!pcapng_write_string_option(pfile, SHB_HARDWARE, hw,
                                         bytes_written, err))
                 return FALSE;