git/t/helper/test-trace2.c

#include "test-tool.h"
#include "cache.h"
#include "strvec.h"
#include "run-command.h"
#include "exec-cmd.h"
#include "config.h"

typedef int(fn_unit_test)(int argc, const char **argv);

struct unit_test {
	fn_unit_test *ut_fn;
	const char *ut_name;
	const char *ut_usage;
};

#define MyOk 0
#define MyError 1

static int get_i(int *p_value, const char *data)
{
	char *endptr;

	if (!data || !*data)
		return MyError;

	*p_value = strtol(data, &endptr, 10);
	if (*endptr || errno == ERANGE)
		return MyError;

	return MyOk;
}

/*
 * Cause process to exit with the requested value via "return".
 *
 * Rely on test-tool.c:cmd_main() to call trace2_cmd_exit()
 * with our result.
 *
 * Test harness can confirm:
 * [] the process-exit value.
 * [] the "code" field in the "exit" trace2 event.
 * [] the "code" field in the "atexit" trace2 event.
 * [] the "name" field in the "cmd_name" trace2 event.
 * [] "def_param" events for all of the "interesting" pre-defined
 * config settings.
 */
static int ut_001return(int argc, const char **argv)
{
	int rc;

	if (get_i(&rc, argv[0]))
		die("expect <exit_code>");

	return rc;
}

/*
 * Cause the process to exit with the requested value via "exit()".
 *
 * Test harness can confirm:
 * [] the "code" field in the "exit" trace2 event.
 * [] the "code" field in the "atexit" trace2 event.
 * [] the "name" field in the "cmd_name" trace2 event.
 * [] "def_param" events for all of the "interesting" pre-defined
 * config settings.
 */
static int ut_002exit(int argc, const char **argv)
{
	int rc;

	if (get_i(&rc, argv[0]))
		die("expect <exit_code>");

	exit(rc);
}

/*
 * Send an "error" event with each value in argv.  Normally, git only issues
 * a single "error" event immediately before issuing an "exit" event (such
 * as in die() or BUG()), but multiple "error" events are allowed.
 *
 * Test harness can confirm:
 * [] a trace2 "error" event for each value in argv.
 * [] the "name" field in the "cmd_name" trace2 event.
 * [] (optional) the file:line in the "exit" event refers to this function.
 */
static int ut_003error(int argc, const char **argv)
{
	int k;

	if (!argv[0] || !*argv[0])
		die("expect <error_message>");

	for (k = 0; k < argc; k++)
		error("%s", argv[k]);

	return 0;
}

/*
 * Run a child process and wait for it to finish and exit with its return code.
 * test-tool trace2 004child [<child-command-line>]
 *
 * For example:
 * test-tool trace2 004child git version
 * test-tool trace2 004child test-tool trace2 001return 0
 * test-tool trace2 004child test-tool trace2 004child test-tool trace2 004child
 * test-tool trace2 004child git -c alias.xyz=version xyz
 *
 * Test harness can confirm:
 * [] the "name" field in the "cmd_name" trace2 event.
 * [] that the outer process has a single component SID (or depth "d0" in
 *    the PERF stream).
 * [] that "child_start" and "child_exit" events are generated for the child.
 * [] if the child process is an instrumented executable:
 *    [] that "version", "start", ..., "exit", and "atexit" events are
 *       generated by the child process.
 *    [] that the child process events have a multiple component SID (or
 *       depth "dN+1" in the PERF stream).
 * [] that the child exit code is propagated to the parent process "exit"
 *    and "atexit" events..
 * [] (optional) that the "t_abs" field in the child process "atexit" event
 *    is less than the "t_rel" field in the "child_exit" event of the parent
 *    process.
 * [] if the child process is like the alias example above,
 *    [] (optional) the child process attempts to run "git-xyx" as a dashed
 *       command.
 *    [] the child process emits an "alias" event with "xyz" => "version"
 *    [] the child process runs "git version" as a child process.
 *    [] the child process has a 3 component SID (or depth "d2" in the PERF
 *       stream).
 */
static int ut_004child(int argc, const char **argv)
{
	int result;

	/*
	 * Allow empty <child_command_line> so we can do arbitrarily deep
	 * command nesting and let the last one be null.
	 */
	if (!argc)
		return 0;

	result = run_command_v_opt(argv, 0);
	exit(result);
}

/*
 * Exec a git command.  This may either create a child process (Windows)
 * or replace the existing process.
 * test-tool trace2 005exec <git_command_args>
 *
 * For example:
 * test-tool trace2 005exec version
 *
 * Test harness can confirm (on Windows):
 * [] the "name" field in the "cmd_name" trace2 event.
 * [] that the outer process has a single component SID (or depth "d0" in
 *    the PERF stream).
 * [] that "exec" and "exec_result" events are generated for the child
 *    process (since the Windows compatibility layer fakes an exec() with
 *    a CreateProcess(), WaitForSingleObject(), and exit()).
 * [] that the child process has multiple component SID (or depth "dN+1"
 *    in the PERF stream).
 *
 * Test harness can confirm (on platforms with a real exec() function):
 * [] TODO talk about process replacement and how it affects SID.
 */
static int ut_005exec(int argc, const char **argv)
{
	int result;

	if (!argc)
		return 0;

	result = execv_git_cmd(argv);
	return result;
}

static int ut_006data(int argc, const char **argv)
{
	const char *usage_error =
		"expect <cat0> <k0> <v0> [<cat1> <k1> <v1> [...]]";

	if (argc % 3 != 0)
		die("%s", usage_error);

	while (argc) {
		if (!argv[0] || !*argv[0] || !argv[1] || !*argv[1] ||
		    !argv[2] || !*argv[2])
			die("%s", usage_error);

		trace2_data_string(argv[0], the_repository, argv[1], argv[2]);
		argv += 3;
		argc -= 3;
	}

	return 0;
}

static int ut_007bug(int argc, const char **argv)
{
	/*
	 * Exercise BUG() to ensure that the message is printed to trace2.
	 */
	BUG("the bug message");
}

/*
 * Usage:
 *     test-tool trace2 <ut_name_1> <ut_usage_1>
 *     test-tool trace2 <ut_name_2> <ut_usage_2>
 *     ...
 */
#define USAGE_PREFIX "test-tool trace2"

/* clang-format off */
static struct unit_test ut_table[] = {
	{ ut_001return,   "001return", "<exit_code>" },
	{ ut_002exit,     "002exit",   "<exit_code>" },
	{ ut_003error,    "003error",  "<error_message>+" },
	{ ut_004child,    "004child",  "[<child_command_line>]" },
	{ ut_005exec,     "005exec",   "<git_command_args>" },
	{ ut_006data,     "006data",   "[<category> <key> <value>]+" },
	{ ut_007bug,      "007bug",    "" },
};
/* clang-format on */

/* clang-format off */
#define for_each_ut(k, ut_k)			\
	for (k = 0, ut_k = &ut_table[k];	\
	     k < ARRAY_SIZE(ut_table);		\
	     k++, ut_k = &ut_table[k])
/* clang-format on */

static int print_usage(void)
{
	int k;
	struct unit_test *ut_k;

	fprintf(stderr, "usage:\n");
	for_each_ut (k, ut_k)
		fprintf(stderr, "\t%s %s %s\n", USAGE_PREFIX, ut_k->ut_name,
			ut_k->ut_usage);

	return 129;
}

/*
 * Issue various trace2 events for testing.
 *
 * We assume that these trace2 routines has already been called:
 *    [] trace2_initialize()      [common-main.c:main()]
 *    [] trace2_cmd_start()       [common-main.c:main()]
 *    [] trace2_cmd_name()        [test-tool.c:cmd_main()]
 *    [] tracd2_cmd_list_config() [test-tool.c:cmd_main()]
 * So that:
 *    [] the various trace2 streams are open.
 *    [] the process SID has been created.
 *    [] the "version" event has been generated.
 *    [] the "start" event has been generated.
 *    [] the "cmd_name" event has been generated.
 *    [] this writes various "def_param" events for interesting config values.
 *
 * We further assume that if we return (rather than exit()), trace2_cmd_exit()
 * will be called by test-tool.c:cmd_main().
 */
int cmd__trace2(int argc, const char **argv)
{
	int k;
	struct unit_test *ut_k;

	argc--; /* skip over "trace2" arg */
	argv++;

	if (argc)
		for_each_ut (k, ut_k)
			if (!strcmp(argv[0], ut_k->ut_name))
				return ut_k->ut_fn(argc - 1, argv + 1);

	return print_usage();
}