Skip rename() on NULL destfile in curl_download_internal()

Avoid a potential segfault that may occur if we use a temporary file and
fail to build the destination file name from the effective URL.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index 9f1285d0..fd5c9289 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -385,12 +385,16 @@ cleanup:
 	}
 
 	if(ret == 0) {
-		if(rename(tempfile, destfile)) {
-			_alpm_log(handle, ALPM_LOG_ERROR, _("could not rename %s to %s (%s)\n"),
-					tempfile, destfile, strerror(errno));
-			ret = -1;
+		if (destfile) {
+			if(rename(tempfile, destfile)) {
+				_alpm_log(handle, ALPM_LOG_ERROR, _("could not rename %s to %s (%s)\n"),
+						tempfile, destfile, strerror(errno));
+				ret = -1;
+			} else if(final_file) {
+				*final_file = strdup(strrchr(destfile, '/') + 1);
+			}
 		} else if(final_file) {
-			*final_file = strdup(strrchr(destfile, '/') + 1);
+			*final_file = strdup(strrchr(tempfile, '/') + 1);
 		}
 	}