[RESEND PATCH] perf tools: Add levenshtein ENOMEM check

From: Paran Lee
Date: Wed Mar 15 2023 - 02:12:13 EST


The levenshtein algorithm requires exception handling
when making dynamic allocations strings.

Signed-off-by: Paran Lee <p4ranlee@xxxxxxxxx>
---
tools/perf/util/help-unknown-cmd.c | 6 +++++-
tools/perf/util/levenshtein.c | 16 ++++++++++------
2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/help-unknown-cmd.c b/tools/perf/util/help-unknown-cmd.c
index ab9e16123626..a70ef339b8af 100644
--- a/tools/perf/util/help-unknown-cmd.c
+++ b/tools/perf/util/help-unknown-cmd.c
@@ -74,10 +74,14 @@ const char *help_unknown_cmd(const char *cmd)

if (main_cmds.cnt) {
/* This reuses cmdname->len for similarity index */
- for (i = 0; i < main_cmds.cnt; ++i)
+ for (i = 0; i < main_cmds.cnt; ++i) {
main_cmds.names[i]->len =
levenshtein(cmd, main_cmds.names[i]->name, 0, 2, 1, 4);

+ if(main_cmds.names[i]->len == -ENOMEM)
+ goto end;
+ }
+
qsort(main_cmds.names, main_cmds.cnt,
sizeof(*main_cmds.names), levenshtein_compare);

diff --git a/tools/perf/util/levenshtein.c b/tools/perf/util/levenshtein.c
index 6a6712635aa4..0f0f244f142b 100644
--- a/tools/perf/util/levenshtein.c
+++ b/tools/perf/util/levenshtein.c
@@ -45,11 +45,17 @@ int levenshtein(const char *string1, const char *string2,
int w, int s, int a, int d)
{
int len1 = strlen(string1), len2 = strlen(string2);
- int *row0 = malloc(sizeof(int) * (len2 + 1));
- int *row1 = malloc(sizeof(int) * (len2 + 1));
- int *row2 = malloc(sizeof(int) * (len2 + 1));
+ int *rows, *row0, *row1, *row2;
int i, j;

+ rows = malloc(3 * sizeof(int) * (len2 + 1));
+ if(!rows)
+ return -ENOMEM;
+
+ row0 = &rows[0];
+ row1 = &rows[1];
+ row2 = &rows[2];
+
for (j = 0; j <= len2; j++)
row1[j] = j * a;
for (i = 0; i < len1; i++) {
@@ -79,9 +85,7 @@ int levenshtein(const char *string1, const char *string2,
}

i = row1[len2];
- free(row0);
- free(row1);
- free(row2);
+ free(rows);

return i;
}
--
2.34.1