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[PATCH v2 2/3] Fix memory leak in apply_patch in apply.c.

From
Jared Hance <jaredhance@gmail.com>
Date
Mar 3, 2012, 14:40 UTC
Message-ID
<e631bb2059c800f9d49eed51cfa5ba4d04106a2e.1330785363.git.jaredhance@gmail.com>
In-Reply-To
<cover.1330740964.git.jaredhance@gmail.com>

In the while loop inside apply_patch, patch is dynamically allocated with a calloc. However, only unused patches are actually free'd; the rest are left in a memory leak. Since a list is actively built up consisting of the used patches, they can simply be iterated and free'd at the end of the function.

In addition, the list of fragments should be free'd. To fix this, the utility function free_patch has been implemented. It loops over the entire patch list, and in each patch, loops over the fragment list, freeing the fragments, followed by the patch in the list. It frees both patch and patch->next.

The main caveat is that the text in a fragment, ie, patch->fragments->patch, may or may not need to be free'd. The text is dynamically allocated and needs to be freed iff the patch is a binary patch, as allocation occurs in inflate_it.

Signed-off-by: Jared Hance <jaredhance@gmail.com>
---
 builtin/apply.c |   30 +++++++++++++++++++++++++++---
 1 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/builtin/apply.c b/builtin/apply.c
index 389898f..a73d339 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -196,6 +196,30 @@ struct patch {
 	struct patch *next;
 };
 
+static void free_patch(struct patch *patch) {
+    while(patch != NULL) {
+	struct patch *patch_next;
+	struct fragment *fragment;
+
+	patch_next = patch->next;
+
+	fragment = patch->fragments;
+	while(fragment != NULL) {
+	    struct fragment *fragment_next = fragment->next;
+	    if(fragment->patch != NULL) {
+		if(patch->is_binary) {
+		    free((void*) fragment->patch);
+		}
+	    }
+	    free(fragment);
+	    fragment = fragment_next;
+	}
+
+	free(patch);
+	patch = patch_next;
+    }
+}
+
 /*
  * A line in a file, len-bytes long (includes the terminating LF,
  * except for an incomplete line at the end if the file ends with
@@ -3687,7 +3711,6 @@ static int apply_patch(int fd, const char *filename, int options)
 	struct patch *list = NULL, **listp = &list;
 	int skipped_patch = 0;
 
-	/* FIXME - memory leak when using multiple patch files as inputs */
 	memset(&fn_table, 0, sizeof(struct string_list));
 	patch_input_file = filename;
 	read_patch_file(&buf, fd);
@@ -3712,8 +3735,7 @@ static int apply_patch(int fd, const char *filename, int options)
 			listp = &patch->next;
 		}
 		else {
-			/* perhaps free it a bit better? */
-			free(patch);
+			free_patch(patch);
 			skipped_patch++;
 		}
 		offset += nr;
@@ -3754,6 +3776,8 @@ static int apply_patch(int fd, const char *filename, int options)
 	if (summary)
 		summary_patch_list(list);
 
+	free_patch(list);
+
 	strbuf_release(&buf);
 	return 0;
 }
-- 
1.7.3.4
Previous: Jeff EplerNext: Jared Hance
Message 14 of 18 in “Fix some documented fixmes”
  1. 0/3 Fix some documented fixmesJared Hance, Mar 3, 2012
  2. 1/3 Use startup_info->prefix rather than prefix.Jared Hance, Mar 3, 2012
  3. Junio C HamanoMar 3, 2012
  4. Nguyen Thai Ngoc DuyMar 3, 2012
  5. Junio C HamanoMar 3, 2012
  6. Jared HanceMar 3, 2012
  7. 2/3 Fix memory leak in apply_patch in apply.c.Jared Hance, Mar 3, 2012
  8. Junio C HamanoMar 3, 2012
  9. 3/3 Add threaded versions of functions in symlinks.c.Jared Hance, Mar 3, 2012
  10. Junio C HamanoMar 3, 2012
  11. 0/3 Fix a few documents fixmesJared Hance, Mar 3, 2012
  12. 1/3 Use startup_info->prefix rather than prefix.Jared Hance, Mar 3, 2012
  13. Jeff EplerMar 3, 2012
  14. 2/3 Fix memory leak in apply_patch in apply.c.Jared Hance, Mar 3, 2012
  15. Jared HanceMar 3, 2012
  16. Junio C HamanoMar 3, 2012
  17. 3/3 Add threaded versions of functions in symlinks.c.Jared Hance, Mar 3, 2012
  18. Thomas RastMar 5, 2012

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