root/lib/common/mock.c

/* */

DEFINITIONS

1. __wrap_calloc
2. __wrap_getenv
3. __wrap_getpwnam_r
4. __wrap_uname

   1 /*
   2  * Copyright 2021-2022 the Pacemaker project contributors
   3  *
   4  * The version control history for this file may have further details.
   5  *
   6  * This source code is licensed under the GNU Lesser General Public License
   7  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
   8  */
   9 
  10 #include <pwd.h>
  11 #include <stdlib.h>
  12 #include <sys/types.h>
  13 #include <sys/utsname.h>
  14 
  15 #include "mock_private.h"
  16 
  17 /* This file is only used when running "make check".  It is built into
  18  * libcrmcommon_test.a, not into libcrmcommon.so.  It is used to support
  19  * constructing mock versions of library functions for unit testing.
  20  *
  21  * Each unit test will only ever want to use a mocked version of one or two
  22  * library functions.  However, we need to mark all the mocked functions as
  23  * wrapped (with -Wl,--wrap= in the LDFLAGS) in libcrmcommon_test.a so that
  24  * all those unit tests can share the same special test library.  The unit
  25  * test then defines its own wrapped function.  Because a unit test won't
  26  * define every single wrapped function, there will be undefined references
  27  * at link time.
  28  *
  29  * This file takes care of those undefined references.  It defines a
  30  * wrapped version of every function that simply calls the real libc
  31  * version.  These wrapped versions are defined with a weak attribute,
  32  * which means the unit tests can define another wrapped version for
  33  * unit testing that will override the version defined here.
  34  *
  35  * HOW TO ADD A MOCKED FUNCTION:
  36  *
  37  * - Define a __wrap_X function here below with the same prototype as the
  38  *   actual function and that just calls __real_X.
  39  * - Add a __real_X and __wrap_X function prototype to mock_private.h.
  40  * - Add the function name to the WRAPPED variable in Makefile.am.
  41  *
  42  * HOW TO USE A MOCKED FUNCTION:
  43  *
  44  * - In the Makefile.am for your new test, add:
  45  *
  46  *   your_fn_test_LDADD = $(top_builddir)/lib/common/libcrmcommon_test.la -lcmocka
  47  *   your_fn_test_LDFLAGS = -Wl,--wrap=X
  48  *
  49  *   You can use multiple wrapped functions by adding multiple -Wl
  50  *   arguments.
  51  * - #include "mock_private.h" in your test file.
  52  * - Add a __wrap_X function with the same prototype as the real function.
  53  * - Write your test cases, using will_return(), mock_type(), and
  54  *   mock_ptr_type() from cmocka.  See existing test cases for details.
  55  */
  56 
  57 void *__attribute__((weak))
  58 __wrap_calloc(size_t nmemb, size_t size) {
     /*  */
  59     return __real_calloc(nmemb, size);
  60 }
  61 
  62 char *__attribute__((weak))
  63 __wrap_getenv(const char *name) {
     /*  */
  64     return __real_getenv(name);
  65 }
  66 
  67 int __attribute__((weak))
  68 __wrap_getpwnam_r(const char *name, struct passwd *pwd,
     /*  */
  69                   char *buf, size_t buflen, struct passwd **result) {
  70     return __real_getpwnam_r(name, pwd, buf, buflen, result);
  71 }
  72 
  73 int __attribute__((weak))
  74 __wrap_uname(struct utsname *buf) {
     /*  */
  75     return __real_uname(buf);
  76 }

/* */