Fix a massive memleak from rpmfiConfigConflictIndex() and optimize it

- rpmfiFNIndex() returns a malloced string since commit
  11116a67864c119e420297984bd9ec4b83fdadd7 but this wasn't taken into
  account in commit 3f996a588a56141df146c33583a13c0542323977, causing
  a massive memory leak on transaction preparations.
- Optimize the entry by avoiding rpmfiFNIndex() and lstat() until
  really necessary, and use a central exit point beyond that so
  we can free fn. Besides fixing the memleak, this gives a small
  but measurable performance improvement on this rather busy path.
- Backported from commit 80ee39da35544253cab12abd54af8754335ac945

1 files changed, 25 insertions, 12 deletions

diff --git a/lib/rpmfi.c b/lib/rpmfi.c
index 40162023f..34d8e2780 100644
--- a/lib/rpmfi.c
+++ b/lib/rpmfi.c
@@ -677,24 +677,33 @@ rpmFileAction rpmfiDecideFateIndex(rpmfi ofi, int oix, rpmfi nfi, int nix,
 
 int rpmfiConfigConflictIndex(rpmfi fi, int ix)
 {
-    const char * fn = rpmfiFNIndex(fi, ix);
+    char * fn = NULL;
     rpmfileAttrs flags = rpmfiFFlagsIndex(fi, ix);
     char buffer[1024];
     rpmFileTypes newWhat, diskWhat;
     struct stat sb;
+    int rc = 0;
 
-    if (!(flags & RPMFILE_CONFIG) || lstat(fn, &sb)) {
+    if (!(flags & RPMFILE_CONFIG))
 	return 0;
-    }
 
-    diskWhat = rpmfiWhatis((rpm_mode_t)sb.st_mode);
+    /* Only links and regular files can be %config, this is kinda moot */
+    /* XXX: Why are we returning 1 here? */
     newWhat = rpmfiWhatis(rpmfiFModeIndex(fi, ix));
-
     if (newWhat != LINK && newWhat != REG)
 	return 1;
 
-    if (diskWhat != newWhat)
-	return 1;
+    /* If it's not on disk, there's nothing to be saved */
+    fn = rpmfiFNIndex(fi, ix);
+    if (lstat(fn, &sb))
+	goto exit;
+
+    /* Files of different types obviously are not identical */
+    diskWhat = rpmfiWhatis((rpm_mode_t)sb.st_mode);
+    if (diskWhat != newWhat) {
+	rc = 1;
+	goto exit;
+    }
     
     memset(buffer, 0, sizeof(buffer));
     if (newWhat == REG) {
@@ -702,21 +711,25 @@ int rpmfiConfigConflictIndex(rpmfi fi, int ix)
 	size_t diglen;
 	const unsigned char *ndigest = rpmfiFDigestIndex(fi,ix, &algo, &diglen);
 	if (rpmDoDigest(algo, fn, 0, (unsigned char *)buffer, NULL))
-	    return 0;	/* assume file has been removed */
+	    goto exit;	/* assume file has been removed */
 	if (ndigest && !memcmp(ndigest, buffer, diglen))
-	    return 0;	/* unmodified config file */
+	    goto exit;	/* unmodified config file */
     } else /* newWhat == LINK */ {
 	const char * nFLink;
 	ssize_t link_len = readlink(fn, buffer, sizeof(buffer) - 1);
 	if (link_len == -1)
-	    return 0;	/* assume file has been removed */
+	    goto exit;	/* assume file has been removed */
 	buffer[link_len] = '\0';
 	nFLink = rpmfiFLinkIndex(fi, ix);
 	if (nFLink && rstreq(nFLink, buffer))
-	    return 0;	/* unmodified config file */
+	    goto exit;	/* unmodified config file */
     }
 
-    return 1;
+    rc = 1;
+
+exit:
+    free(fn);
+    return rc;
 }
 
 static char **duparray(char ** src, int size)