[Patch] libfetch - closing the cached FTP connection

Mark Johnston markjdb at gmail.com
Sun Oct 24 23:45:45 UTC 2010


We've run into problems with pkg_add because of some caching behaviour
in libfetch. Specifically, after an FTP transfer, a connection to the
FTP server is held open by the cached_connection pointer in ftp.c. Thus,
if one requests a file with fetchGetFTP() and later closes the
connection with fclose(), a socket is still held open, and the
descriptor is copied to any child processes.

What was apparently happening was that we were using pkg_add to install
a package whose install script started a daemon, which consequently kept
open a connection to our FTP server. This is "fixed" in our tree with a
closefrom(2) in pkg_install at an appropriate point, but I thought that
libfetch should provide some way of forcing a close on the cached
connection so that the above hack isn't necessary.

My solution is provided in a patch below. It's not particularly elegant,
but I can't see a better way to go about it. I was hoping to get some
feedback and to see if anyone can come up with a better approach. I'll
also update the libfetch man page if the patch below is acceptable.


diff --git a/lib/libfetch/fetch.h b/lib/libfetch/fetch.h
index 11a3f77..d379e63 100644
--- a/lib/libfetch/fetch.h
+++ b/lib/libfetch/fetch.h
@@ -109,6 +109,7 @@ FILE		*fetchGetFTP(struct url *, const char *);
 FILE		*fetchPutFTP(struct url *, const char *);
 int		 fetchStatFTP(struct url *, struct url_stat *, const char *);
 struct url_ent	*fetchListFTP(struct url *, const char *);
+void		 fetchCloseCachedFTP();
 /* Generic functions */
 FILE		*fetchXGetURL(const char *, struct url_stat *, const char *);
diff --git a/lib/libfetch/ftp.c b/lib/libfetch/ftp.c
index 0983a76..746ad54 100644
--- a/lib/libfetch/ftp.c
+++ b/lib/libfetch/ftp.c
@@ -1204,3 +1204,12 @@ fetchListFTP(struct url *url __unused, const char *flags __unused)
 	warnx("fetchListFTP(): not implemented");
 	return (NULL);
+ * Force close the cached connection.
+ */
+	ftp_disconnect(cached_connection);
diff --git a/usr.sbin/pkg_install/lib/url.c b/usr.sbin/pkg_install/lib/url.c
index 914ce39..68f31bb 100644
--- a/usr.sbin/pkg_install/lib/url.c
+++ b/usr.sbin/pkg_install/lib/url.c
@@ -163,5 +163,6 @@ fileGetURL(const char *base, const char *spec, int keep_package)
 	printf("tar command returns %d status\n", WEXITSTATUS(pstat));
     if (rp && (isatty(0) || Verbose))
 	printf(" Done.\n");
+    fetchCloseCachedFTP();
     return rp;

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