diff --git a/builtin/checkout-index.c b/builtin/checkout-index.c
index 69e167b16c284534d84019ba0f781fe2c3a889dd..61e75eb60c992e38ddf195abad564a76cbf934cb 100644
--- a/builtin/checkout-index.c
+++ b/builtin/checkout-index.c
@@ -14,7 +14,7 @@
 static int line_termination = '\n';
 static int checkout_stage; /* default to checkout stage0 */
 static int to_tempfile;
-static char topath[4][PATH_MAX + 1];
+static char topath[4][TEMPORARY_FILENAME_LENGTH + 1];
 
 static struct checkout state;
 
diff --git a/cache.h b/cache.h
index 70ad174dd98c82503d246f8d9e5a253805e44076..9aa46e70c3faf7eb678eeef7b825ae52fb4bc0bf 100644
--- a/cache.h
+++ b/cache.h
@@ -976,6 +976,7 @@ struct checkout {
 		 refresh_cache:1;
 };
 
+#define TEMPORARY_FILENAME_LENGTH 25
 extern int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath);
 
 struct cache_def {
diff --git a/entry.c b/entry.c
index acc892f9a62b5bc3d3442b044b29bf8d763bf3ba..7b7aa8167adade20f38cfb2709e02b3ed31f11a4 100644
--- a/entry.c
+++ b/entry.c
@@ -234,19 +234,30 @@ static int check_path(const char *path, int len, struct stat *st, int skiplen)
 	return lstat(path, st);
 }
 
+/*
+ * Write the contents from ce out to the working tree.
+ *
+ * When topath[] is not NULL, instead of writing to the working tree
+ * file named by ce, a temporary file is created by this function and
+ * its name is returned in topath[], which must be able to hold at
+ * least TEMPORARY_FILENAME_LENGTH bytes long.
+ */
 int checkout_entry(struct cache_entry *ce,
 		   const struct checkout *state, char *topath)
 {
-	static char path[PATH_MAX + 1];
+	static struct strbuf path_buf = STRBUF_INIT;
+	char *path;
 	struct stat st;
-	int len = state->base_dir_len;
+	int len;
 
 	if (topath)
 		return write_entry(ce, topath, state, 1);
 
-	memcpy(path, state->base_dir, len);
-	strcpy(path + len, ce->name);
-	len += ce_namelen(ce);
+	strbuf_reset(&path_buf);
+	strbuf_add(&path_buf, state->base_dir, state->base_dir_len);
+	strbuf_add(&path_buf, ce->name, ce_namelen(ce));
+	path = path_buf.buf;
+	len = path_buf.len;
 
 	if (!check_path(path, len, &st, state->base_dir_len)) {
 		unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);