NNTPC: default overview format - solved (re-post)

[rs@system.ptv.de (Ralph Schmieder)]

Hello,

in a previous post I've explained a problem with nntpcache and
newsservers which provide the XOVER command but no LIST overview.fmt.
I've checked the source and found out, that there's no code in
getListServer (LIST.C) to use a default overview format.

Additionally, the code which writes the overview.fmt to a file in the
newsserver dir, is (IMO) buggy. Currently, it writes the overview.fmt
to the file as:

SubjectFromDateMessage-IDReferencesBytesLines

Notice that there are no ':' between the fields, all fields are
'glued' together and that all fields are in the same line. It should
be (to get the code working which reads the overview.fmt file from
disk cache in getListServer):

Subject:
From:
Date:
Message-ID:
References:
Bytes:
Lines:

(note, that every field is in a separate line and has a ':' appended).

If you look at the appended code from getListServer/LIST.C, it will
crash with a SIGSEGV, when it reads from overview.fmt (f_server_good
== FALSE). The complete overview.fmt is read by one fgets (there is
only one line) and there are _no_ colons, p is nil and list2 will
never contain an element. scfg->overview_fmt = list2->head will cause
the SIGSEGV.

		while (f_server_good? (Cfget(scfg, buf, sizeof buf) &&
		!EL(buf)): (fgets(buf, sizeof(buf), fp)!=NULL))
		{
			char *p = strchr (buf, ':');
			if (!p)
				continue;
			bytes += strlen(buf);
			*p = '\0';
			hash = strHash (hash, buf);
			list2 = strListAdd (list2, buf);
			if (f_server_good)
				fputs(buf, fp);
		}
[...]
		scfg->overview_fmt = list2->head;

My patch applies the default overview format defined in the config
file for servers which don't supply the "LIST overview.fmt" and
corrects the problem with the overview.fmt files. I hope, that this
patch is useful for someone out there. Comments are welcome.

regards
ralph

p.s. I'm posting this a second time -- think it hasn't made it to the
list the first time.

--- list.c.orig	Tue Feb 18 16:05:04 1997
+++ list.c	Tue Feb 18 16:04:38 1997
@@ -269,6 +269,7 @@
 	FILE *fp=NULL;
 
 	time_t tim=time(NULL);
+	bool f_default_overview_fmt_used = FALSE;
 
 	log (("checking server %s for '%s'", scfg->host, list->name));
 	if (list->type == l_active)
@@ -278,7 +279,40 @@
 	Cfflush(scfg);
 	if (!Cfget (scfg, buf, sizeof buf))
 		goto dropped;
-	if (strToi(buf) != NNTP_LIST_FOLLOWS_VAL)
+	if (strToi(buf) != NNTP_LIST_FOLLOWS_VAL && list->type ==
l_overview_fmt) 
+	{
+		if(overviewFmtDef == NULL) 
+		{
+			logw (("no default overview format
defined!"));
+			chdir (con.cacheDir);
+			return 0;
+		}
+		else 
+		{
+			struct strList *list_tmp=overviewFmtDef;
+			
+			setGroupDir(NULL, scfg);
+			if ((fp = fopen(list->name, "w")) == NULL)
+			{
+				loge(("couldn't write %s/%s (default)
to disk cache", scfg->host, list->name));
+				chdir (con.cacheDir);
+				return 0;
+			}
+
+			while(list_tmp != NULL) {
+				fputs(list_tmp->data, fp);
+				fputs(":\n", fp);
+				list_tmp = list_tmp->next;
+			}
+
+			fclose (fp);
+
+			logw (("default overview format used!"));
+			f_default_overview_fmt_used = TRUE;
+		}
+	}
+
+	if (strToi(buf) != NNTP_LIST_FOLLOWS_VAL && list->type !=
l_overview_fmt)
 	{
 		buf[MAX_SYSLOG]='\0';
 		logw (("list %s on %s error: %s", list->name,
scfg->host, buf));
@@ -291,7 +325,7 @@
 		struct strList *list2=NULL;
 		U32 hash=0;
 		bool f_server_good;
-		if (!(scfg=attachServer(scfg)))
+		if (f_default_overview_fmt_used ||
!(scfg=attachServer(scfg)))
 		{
 		retry_disk:
 			if ((fp = fopen(list->name, "r")) == NULL)
@@ -319,8 +353,10 @@
 			*p = '\0';
 			hash = strHash (hash, buf);
 			list2 = strListAdd (list2, buf);
-			if (f_server_good)
+			if (f_server_good) {
 				fputs(buf, fp);
+				fputs(":\n", fp);
+			}
 		}
 		if (fp)
 			fclose (fp);