Use alternative string trimming in auth service

Previous string trimming was changing the strings supplied by MQ to be null-terminated.  MQ uses fixed-width strings, and the changes to the data could cause problems in the queue manager.

authservice/mqhtpass/src/log_test.c

@@ -0,0 +1,120 @@
+/*
+© Copyright IBM Corporation 2022
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "log.h"
+
+// Headers for multi-threaded tests
+#include <pthread.h>
+
+// Start a test and log the function name
+#define test_start() printf("=== RUN: %s\n", __func__)
+
+// Indicate test has passed
+#define test_pass() printf("--- PASS: %s\n", __func__)
+
+// The length of strings used in the tests
+#define STR_LEN 5
+
+// Indicate test has failed
+void test_fail(const char *test_name)
+{
+  printf("--- FAIL: %s\n", test_name);
+  exit(1);
+}
+
+// Print a fixed-width string in hexadecimal
+void print_hex(char fw_string[STR_LEN])
+{
+  printf("[");
+  for (int i=0; i<STR_LEN; i++)
+  {
+    printf("%02x", fw_string[i]);
+    if (i < STR_LEN-1)
+      printf(",");
+  }
+  printf("]");
+}
+
+// ----------------------------------------------------------------------------
+// Tests for string manipulation
+// ----------------------------------------------------------------------------
+
+void test_trimmed_len(const char *test_name, char fw_string[STR_LEN], int expected_len)
+{
+  printf("=== RUN: %s\n", test_name);
+  int len;
+  // Create a copy of the fixed-width string
+  char fw_string2[STR_LEN];
+  memcpy(fw_string2, fw_string, STR_LEN * sizeof(char));
+  // Call the function under test
+  len = trimmed_len(fw_string, STR_LEN);
+  // Check the result is correct
+  if (len != expected_len)
+  {
+    printf("%s: Expected result to be %d; got %d\n", __func__, expected_len, len);
+    test_fail(test_name);
+  }
+  // Check that the original string has not been changed
+  for (int i=0; i<STR_LEN; i++)
+  {
+    if (fw_string[i] != fw_string2[i])
+    {
+      printf("%c-%c\n", fw_string[i], fw_string2[i]);
+      printf("%s: Expected string to be identical to input hex ", __func__);
+      print_hex(fw_string2);
+      printf("; got hex ");
+      print_hex(fw_string);
+      printf("\n");
+      test_fail(test_name);
+    }
+  }
+  printf("--- PASS: %s\n", test_name);
+}
+
+void test_trimmed_len_normal()
+{
+  char fw_string[STR_LEN] = {'a','b','c',' ',' '};
+  test_trimmed_len(__func__, fw_string, 3);
+}
+
+void test_trimmed_len_full()
+{
+  char fw_string[STR_LEN] = {'a','b','c','d','e'};
+  test_trimmed_len(__func__, fw_string, 5);
+}
+
+void test_trimmed_len_empty()
+{
+  char fw_string[STR_LEN] = {' ',' ',' ',' ',' '};
+  test_trimmed_len(__func__, fw_string, 0);
+}
+
+// ----------------------------------------------------------------------------
+
+int main()
+{
+  // Turn on debugging for the tests
+  setenv("DEBUG", "true", true);
+  log_init("log_test.log");
+  test_trimmed_len_normal();
+  test_trimmed_len_full();
+  test_trimmed_len_empty();
+  log_close();
+}