test: use error-checking strncat/strncpy replacements

test.c

@@ -1413,11 +1413,81 @@ const struct message responses[] =
 , {.name= NULL } /* sentinel */
 };
 
+/* strnlen() is a POSIX.2008 addition. Can't rely on it being available so
+ * define it ourselves.
+ */
+size_t
+strnlen(const char *s, size_t maxlen)
+{
+  const char *p;
+
+  p = memchr(s, '\0', maxlen);
+  if (p == NULL)
+    return maxlen;
+
+  return p - s;
+}
+
+size_t
+strlncat(char *dst, size_t len, const char *src, size_t n)
+{
+  size_t slen;
+  size_t dlen;
+  size_t rlen;
+  size_t ncpy;
+
+  slen = strnlen(src, n);
+  dlen = strnlen(dst, len);
+
+  if (dlen < len) {
+    rlen = len - dlen;
+    ncpy = slen < rlen ? slen : (rlen - 1);
+    memcpy(dst + dlen, src, ncpy);
+    dst[dlen + ncpy] = '\0';
+  }
+
+  assert(len > slen + dlen);
+  return slen + dlen;
+}
+
+size_t
+strlcat(char *dst, const char *src, size_t len)
+{
+  return strlncat(dst, len, src, (size_t) -1);
+}
+
+size_t
+strlncpy(char *dst, size_t len, const char *src, size_t n)
+{
+  size_t slen;
+  size_t ncpy;
+
+  slen = strnlen(src, n);
+
+  if (len > 0) {
+    ncpy = slen < len ? slen : (len - 1);
+    memcpy(dst, src, ncpy);
+    dst[ncpy] = '\0';
+  }
+
+  assert(len > slen);
+  return slen;
+}
+
+size_t
+strlcpy(char *dst, const char *src, size_t len)
+{
+  return strlncpy(dst, len, src, (size_t) -1);
+}
+
 int
 request_url_cb (http_parser *p, const char *buf, size_t len)
 {
   assert(p == parser);
-  strncat(messages[num_messages].request_url, buf, len);
+  strlncat(messages[num_messages].request_url,
+           sizeof(messages[num_messages].request_url),
+           buf,
+           len);
   return 0;
 }
 
@@ -1430,7 +1500,10 @@ header_field_cb (http_parser *p, const char *buf, size_t len)
   if (m->last_header_element != FIELD)
     m->num_headers++;
 
-  strncat(m->headers[m->num_headers-1][0], buf, len);
+  strlncat(m->headers[m->num_headers-1][0],
+           sizeof(m->headers[m->num_headers-1][0]),
+           buf,
+           len);
 
   m->last_header_element = FIELD;
 
@@ -1443,7 +1516,10 @@ header_value_cb (http_parser *p, const char *buf, size_t len)
   assert(p == parser);
   struct message *m = &messages[num_messages];
 
-  strncat(m->headers[m->num_headers-1][1], buf, len);
+  strlncat(m->headers[m->num_headers-1][1],
+           sizeof(m->headers[m->num_headers-1][1]),
+           buf,
+           len);
 
   m->last_header_element = VALUE;
 
@@ -1467,7 +1543,10 @@ int
 body_cb (http_parser *p, const char *buf, size_t len)
 {
   assert(p == parser);
-  strncat(messages[num_messages].body, buf, len);
+  strlncat(messages[num_messages].body,
+           sizeof(messages[num_messages].body),
+           buf,
+           len);
   messages[num_messages].body_size += len;
   check_body_is_final(p);
  // printf("body_cb: '%s'\n", requests[num_messages].body);
@@ -2879,15 +2958,15 @@ test_scan (const struct message *r1, const struct message *r2, const struct mess
         parser_init(type_both ? HTTP_BOTH : r1->type);
 
         buf1_len = i;
-        strncpy(buf1, total, buf1_len);
+        strlncpy(buf1, sizeof(buf1), total, buf1_len);
         buf1[buf1_len] = 0;
 
         buf2_len = j - i;
-        strncpy(buf2, total+i, buf2_len);
+        strlncpy(buf2, sizeof(buf1), total+i, buf2_len);
         buf2[buf2_len] = 0;
 
         buf3_len = total_len - j;
-        strncpy(buf3, total+j, buf3_len);
+        strlncpy(buf3, sizeof(buf1), total+j, buf3_len);
         buf3[buf3_len] = 0;
 
         read = parse(buf1, buf1_len);