src/ktrace.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2022 Google Inc, Steven Rostedt <rostedt@goodmis.org>
 */
#include "ktrace.h"

#define EXEC_NAME	"ktrace"

static void usage(char **argv)
{
	printf("usage: %s\n"
	       "\n", EXEC_NAME);
	exit(-1);
}

static void __vdie(const char *fmt, va_list ap, int err)
{
	int ret = errno;

	if (err && errno)
		perror(EXEC_NAME);
	else
		ret = -1;

	fprintf(stderr, "  ");
	vfprintf(stderr, fmt, ap);

	fprintf(stderr, "\n");
	exit(ret);
}

void pdie(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__vdie(fmt, ap, 1);
	va_end(ap);
}

static char *get_cache_file(void)
{
	char *cache_path;
	char *home;
	char *file;
	int ret;

	cache_path = secure_getenv("XDG_CACHE_HOME");
	if (!cache_path) {
		home = secure_getenv("HOME");
		if (!home)
			return NULL;
		ret = asprintf(&cache_path, "%s/.cache", home);
		if (ret < 0)
			return NULL;
	} else {
		/* So we can always free it later */
		cache_path = strdup(cache_path);
	}
	if (!cache_path)
		return NULL;

	ret = asprintf(&file, "%s/ktrace", cache_path);
	free(cache_path);

	return ret < 0 ? NULL : file;
}

static void load_history(struct ccli *ccli)
{
	char *cache_file;

	cache_file = get_cache_file();
	if (!cache_file)
		return;
	ccli_history_load_file(ccli, "ktrace", cache_file);
	free(cache_file);
}

static void save_history(struct ccli *ccli)
{
	char *cache_file;

	cache_file = get_cache_file();
	if (!cache_file)
		return;
	ccli_history_save_file(ccli, "ktrace", cache_file);
	free(cache_file);
}

int main (int argc, char **argv)
{
	struct ccli *ccli;
	struct tep_handle *tep;

	tep = tracefs_local_events(NULL);
	if (!tep) {
		if (errno == EACCES)
			pdie("Failed to initialize tracing directory.\n"
			     "   You do not have permission to read it");
		pdie("Failed to initialize tracing directory");
	}
	ccli = ccli_alloc("ktrace> ", STDIN_FILENO, STDOUT_FILENO);
	if (!ccli)
		pdie("ccli initialization");

	load_history(ccli);

	ccli_register_command(ccli, "help", cmd_help, NULL);
	ccli_register_completion(ccli, "help", help_completion);

	ccli_register_command(ccli, "create", cmd_create, tep);
	ccli_register_completion(ccli, "create", create_completion);

	ccli_register_command(ccli, "enable", cmd_enable, tep);
	ccli_register_completion(ccli, "enable", enable_completion);

	ccli_register_command(ccli, "disable", cmd_disable, tep);
	ccli_register_completion(ccli, "disable", disable_completion);

	ccli_loop(ccli);

	save_history(ccli);
	ccli_free(ccli);

	tep_free(tep);

	return 0;
}