rnews: batch naming and locking

[Miquel van Smoorenburg]

On one of our servers multiple rnews -U processes were running at
the same time, and because rnews doesn't lock the batch it's
processing this resulted in the same posting getting submitted
to innd multiple times. Innd rejected the duplicates, and they
ended up in the bad/ directory filling up the disk.

So I fixed that by making rnews lock the batch using inn_lock_file.
While editting rnews.c I fixed a few other bugs as well:

- in main(), if UnpackOne() fails, Spool() is called but we
  have to rewind the fd first
- ReadRemainder() closes the file when its done - it should
  leave that to the caller
- Unspool() sets UUCPHost unconditionally, it should only
  do that for batches that have a host in their name
- In fact, the remote hostname is never encoded in the batch
  file when spooling it.

Here's the patch:

diff -ruN inn-2.4-20020916.orig/frontends/rnews.c inn-2.4-20020916/frontends/rnews.c
--- inn-2.4-20020916.orig/frontends/rnews.c	Mon Sep 16 14:04:54 2002
+++ inn-2.4-20020916/frontends/rnews.c	Wed Sep 18 12:59:05 2002
@@ -333,7 +333,7 @@
     bool		ok;
 
     /* Turn the descriptor into a stream. */
-    if ((F = fdopen(fd, "r")) == NULL)
+    if ((i = dup(fd)) < 0 || (F = fdopen(i, "r")) == NULL)
         sysdie("cannot fdopen %d", fd);
 
     /* Get an initial allocation, leaving space for the \0. */
@@ -595,7 +595,7 @@
     char		hostname[10];
     int			fd;
     size_t		i;
-    char                *badname;
+    char                *badname, *uuhost;
 
     message_handlers_die(2, message_log_stderr, message_log_syslog_err);
     message_handlers_warn(2, message_log_stderr, message_log_syslog_err);
@@ -624,21 +624,31 @@
                 syswarn("cannot open %s", InputFile);
 	    continue;
 	}
+
+	/* Make sure multiple Unspools don't stomp on eachother */
+	if (!inn_lock_file(fd, INN_LOCK_READ, 0)) {
+	    close(fd);
+	    continue;
+	}
+
 	/* Get UUCP host from spool file, deleting the mktemp XXXXXX suffix. */
-	if ((i = strlen(InputFile)) > 6)
+	uuhost = UUCPHost;
+	hostname[0] = 0;
+	if ((i = strlen(InputFile)) > 6) {
 	    i -= 6;
-	if (i > sizeof hostname - 1)
-	    /* Just in case someone wrote their own spooled file. */
-	    i = sizeof hostname - 1;
-	(void)strncpy(hostname, InputFile, i);
-	hostname[i] = '\0';
-	UUCPHost = hostname;
+	    if (i > sizeof hostname - 1)
+		/* Just in case someone wrote their own spooled file. */
+		i = sizeof hostname - 1;
+	    (void)strncpy(hostname, InputFile, i);
+	    hostname[i] = '\0';
+	    UUCPHost = hostname;
+	}
 	ok = UnpackOne(&fd, &i);
-	(void)close(fd);
 	WaitForChildren(i);
+	UUCPHost = uuhost;
 
 	if (!ok) {
-            badname = concat(PathBadNews, "/XXXXXX", (char *) 0);
+            badname = concat(PathBadNews, "/", hostname, "XXXXXX", (char *) 0);
             fd = mkstemp(badname);
             if (fd < 0)
                 sysdie("cannot create temporary file");
@@ -646,11 +656,13 @@
             warn("cant unspool saving to %s", badname);
 	    if (rename(InputFile, badname) < 0)
                 sysdie("cannot rename %s to %s", InputFile, badname);
+	    (void)close(fd);
 	    continue;
 	}
 
 	if (unlink(InputFile) < 0)
             syswarn("cannot remove %s", InputFile);
+	(void)close(fd);
     }
     (void)closedir(dp);
 
@@ -678,7 +690,8 @@
 
     if (mode == 'N')
 	exit(9);
-    tmpspool = concatpath(innconf->pathincoming, ".XXXXXX");
+    tmpspool = concat(innconf->pathincoming, "/.",
+		UUCPHost ? UUCPHost : "", "XXXXXX", (char *)0);
     spfd = mkstemp(tmpspool);
     if (spfd < 0)
         sysdie("cannot create temporary batch file %s", tmpspool);
@@ -709,7 +722,8 @@
     }
 
     /* Move temp file into the spool area, and exit appropriately. */
-    spoolfile = concatpath(innconf->pathincoming, "XXXXXX");
+    spoolfile = concat(innconf->pathincoming, "/",
+		UUCPHost ? UUCPHost : "", "XXXXXX", (char *)0);
     spfd = mkstemp(spoolfile);
     if (spfd < 0) {
         syswarn("cannot create spool file %s", spoolfile);
@@ -879,8 +893,11 @@
     if (mode == 'U')
 	Unspool();
     else {
-	if (!UnpackOne(&fd, &count))
+	if (!UnpackOne(&fd, &count)) {
+	    lseek(fd, 0, 0);
 	    Spool(fd, mode);
+	}
+	close(fd);
 	WaitForChildren(count);
     }