linux/tools/objtool/objtool.c

/*
 * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

/*
 * objtool:
 *
 * The 'check' subcmd analyzes every .o file and ensures the validity of its
 * stack trace metadata.  It enforces a set of rules on asm code and C inline
 * assembly code so that stack traces can be reliable.
 *
 * For more information, see tools/objtool/Documentation/stack-validation.txt.
 */

#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <subcmd/exec-cmd.h>
#include <subcmd/pager.h>

#include "builtin.h"

#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))

struct cmd_struct {
	const char *name;
	int (*fn)(int, const char **);
	const char *help;
};

static const char objtool_usage_string[] =
	"objtool [OPTIONS] COMMAND [ARGS]";

static struct cmd_struct objtool_cmds[] = {
	{"check",	cmd_check,	"Perform stack metadata validation on an object file" },
};

bool help;

static void cmd_usage(void)
{
	unsigned int i, longest = 0;

	printf("\n usage: %s\n\n", objtool_usage_string);

	for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
		if (longest < strlen(objtool_cmds[i].name))
			longest = strlen(objtool_cmds[i].name);
	}

	puts(" Commands:");
	for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
		printf("   %-*s   ", longest, objtool_cmds[i].name);
		puts(objtool_cmds[i].help);
	}

	printf("\n");

	exit(1);
}

static void handle_options(int *argc, const char ***argv)
{
	while (*argc > 0) {
		const char *cmd = (*argv)[0];

		if (cmd[0] != '-')
			break;

		if (!strcmp(cmd, "--help") || !strcmp(cmd, "-h")) {
			help = true;
			break;
		} else {
			fprintf(stderr, "Unknown option: %s\n", cmd);
			fprintf(stderr, "\n Usage: %s\n",
				objtool_usage_string);
			exit(1);
		}

		(*argv)++;
		(*argc)--;
	}
}

static void handle_internal_command(int argc, const char **argv)
{
	const char *cmd = argv[0];
	unsigned int i, ret;

	for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
		struct cmd_struct *p = objtool_cmds+i;

		if (strcmp(p->name, cmd))
			continue;

		ret = p->fn(argc, argv);

		exit(ret);
	}

	cmd_usage();
}

int main(int argc, const char **argv)
{
	static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";

	/* libsubcmd init */
	exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
	pager_init(UNUSED);

	argv++;
	argc--;
	handle_options(&argc, &argv);

	if (!argc || help)
		cmd_usage();

	handle_internal_command(argc, argv);

	return 0;
}