From: jamie.couture at gmail.com (Jamie Couture)
Subject: [PATCH 1/1] move LCS table away from the stack
Date: Fri, 9 Sep 2011 00:43:10 -0400 [thread overview]
Message-ID: <1315543390-12451-2-git-send-email-jamie.couture@gmail.com> (raw)
In-Reply-To: <1315543390-12451-1-git-send-email-jamie.couture@gmail.com>
From: Jamie Couture <jamie.couture at gmail.com>
Minified files such as javascript, or something similar, where very long
single lines to compare when printing deferred line changes would have
caused segfaults.
Signed-off-by: Jamie Couture <jamie.couture at gmail.com>
---
cgit.h | 12 ++++++++++++
ui-ssdiff.c | 32 ++++++++++++++++++++++++++++++--
2 files changed, 42 insertions(+), 2 deletions(-)
diff --git a/cgit.h b/cgit.h
index bad66f0..1ff5cb3 100644
--- a/cgit.h
+++ b/cgit.h
@@ -47,6 +47,18 @@
*/
#define PAGE_ENCODING "UTF-8"
+/*
+ * ssdiff line limits
+ */
+#ifndef MAX_SSDIFF_M
+#define MAX_SSDIFF_M 1024
+#endif
+
+#ifndef MAX_SSDIFF_N
+#define MAX_SSDIFF_N 1024
+#endif
+#define MAX_SSDIFF_SIZE ((MAX_SSDIFF_M) * (MAX_SSDIFF_N))
+
typedef void (*configfn)(const char *name, const char *value);
typedef void (*filepair_fn)(struct diff_filepair *pair);
typedef void (*linediff_fn)(char *line, int len);
diff --git a/ui-ssdiff.c b/ui-ssdiff.c
index 2481585..4df01ed 100644
--- a/ui-ssdiff.c
+++ b/ui-ssdiff.c
@@ -16,16 +16,41 @@ struct deferred_lines {
static struct deferred_lines *deferred_old, *deferred_old_last;
static struct deferred_lines *deferred_new, *deferred_new_last;
+static int **create_lcs_table(size_t m, size_t n)
+{
+ int **L;
+ int i;
+
+ // xcalloc will die if we ran out of memory;
+ // not very helpful for debugging
+ L = (int**)xcalloc(m, sizeof(int *));
+ *L = (int*)xcalloc(m * n, sizeof(int));
+
+ for (i = 1; i < m; i++) {
+ L[i] = *L + i * n;
+ }
+
+ return L;
+}
+
static char *longest_common_subsequence(char *A, char *B)
{
int i, j, ri;
int m = strlen(A);
int n = strlen(B);
- int L[m + 1][n + 1];
- int tmp1, tmp2;
+ int **L;
+ int tmp1, tmp2, length;
int lcs_length;
char *result;
+ length = (m + 1) * (n + 1);
+
+ // We bail if the lines are too long
+ if (length > MAX_SSDIFF_SIZE)
+ return NULL;
+
+ L = create_lcs_table(m + 1, n + 1);
+
for (i = m; i >= 0; i--) {
for (j = n; j >= 0; j--) {
if (A[i] == '\0' || B[j] == '\0') {
@@ -59,6 +84,9 @@ static char *longest_common_subsequence(char *A, char *B)
j += 1;
}
}
+
+ free(*L);
+ free(L);
return result;
}
--
1.7.6
next prev parent reply other threads:[~2011-09-09 4:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-09 4:43 [PATCH 0/1] segfault in cgit jamie.couture
2011-09-09 4:43 ` jamie.couture [this message]
2011-09-11 0:44 ` [PATCH 1/1] move LCS table away from the stack jamie.couture
2011-09-11 0:44 ` [PATCH] " jamie.couture
2011-09-14 6:38 ` hjemli
2011-09-17 22:25 ` [PATCH 1/1] " jamie.couture
2012-01-03 15:12 ` hjemli
2012-01-04 8:59 ` normalperson
2012-01-04 16:57 ` jamie.couture
2012-01-12 3:38 ` jamie.couture
2012-01-12 3:38 ` [PATCH 1/2] correct length check for LCS table jamie.couture
2012-01-12 3:38 ` [PATCH 2/2] use correct type for sizeof jamie.couture
2012-03-18 9:22 ` hjemli
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