utils/ioctl.c

/*
 * Copyright (c) 2008, The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  * Neither the name of Google, Inc. nor the names of its contributors
 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <limits.h>

static void usage() {
	fprintf(stderr, "%s [-l <length>] [-a <argsize>] [-rdh] <device> <ioctlnr>\n"
			"  -l <length>   Length of io buffer\n"
			"  -a <argsize>  Size of each argument (1-8)\n"
			"  -r            Open device in read only mode\n"
			"  -d            Direct argument (no iobuffer)\n"
			"  -h            Print help\n", "ioctl");
	exit(1);
}

static int xstrtoi(const char* s, const char* what) {
	char* endp;
	errno = 0;
	long result = strtol(s, &endp, 0);
	if (errno != 0 || *endp != '\0') {
		error(1, errno, "couldn't parse %s '%s'", what, s);
	}
	if (result > INT_MAX || result < INT_MIN) {
		error(1, errno, "%s '%s' out of range", what, s);
	}
	return result;
}

int main(int argc, char* argv[]) {
	int read_only = 0;
	int length = -1;
	int arg_size = 4;
	int direct_arg = 0;

	void *ioctl_args = NULL;
	uint8_t *ioctl_argp;
	uint8_t *ioctl_argp_save = NULL;
	int rem;

	int c;
	while ((c = getopt(argc, argv, "rdl:a:h")) != -1) {
		switch (c) {
			case 'r':
				read_only = 1;
				break;
			case 'd':
				direct_arg = 1;
				break;
			case 'l':
				length = xstrtoi(optarg, "length");
				break;
			case 'a':
				arg_size = xstrtoi(optarg, "argument size");
				break;
			case 'h':
				usage();
				break;
			default:
				error(1, 0, "invalid option -%c", optopt);
		}
	}

	if (optind + 2 > argc) {
		usage();
	}

	const char* device = argv[optind];
	int fd;
	if (strcmp(device, "-") == 0) {
		fd = STDIN_FILENO;
	} else {
		fd = open(device, read_only ? O_RDONLY : (O_RDWR | O_SYNC));
		if (fd == -1) {
			error(1, errno, "cannot open %s", argv[optind]);
		}
	}
	optind++;

	// IOCTL(2) wants second parameter as a signed int.
	// Let's let the user specify either negative numbers or large positive
	// numbers, for the case where ioctl number is larger than INT_MAX.
	errno = 0;
	char* endp;
	int ioctl_nr = UINT_MAX & strtoll(argv[optind], &endp, 0);
	if (errno != 0 || *endp != '\0') {
		error(1, errno, "couldn't parse ioctl number '%s'", argv[optind]);
	}
	optind++;

	if (direct_arg) {
		arg_size = 4;
		length = 4;
	}

	if (length < 0) {
		length = (argc - optind) * arg_size;
	}
	if (length) {
		ioctl_args = calloc(1, length);

		ioctl_argp_save = ioctl_argp = ioctl_args;
		rem = length;
		while (optind < argc) {
			uint64_t tmp = strtoull(argv[optind], NULL, 0);
			if (rem < arg_size) {
				error(1, 0, "too many arguments");
			}
			memcpy(ioctl_argp, &tmp, arg_size);
			ioctl_argp += arg_size;
			rem -= arg_size;
			optind++;
		}
	}
	printf("sending ioctl 0x%x", ioctl_nr);
	rem = length;
	while (rem--) {
		printf(" 0x%02x", *ioctl_argp_save++);
	}
	printf(" to %s\n", device);

	int res;
	if (direct_arg)
		res = ioctl(fd, ioctl_nr, *(uint32_t*)ioctl_args);
	else if (length)
		res = ioctl(fd, ioctl_nr, ioctl_args);
	else
		res = ioctl(fd, ioctl_nr, 0);
	if (res < 0) {
		free(ioctl_args);
		error(1, errno, "ioctl 0x%x failed (returned %d)", ioctl_nr, res);
	}

	if (length) {
		printf("return buf:");
		ioctl_argp = ioctl_args;
		rem = length;
		while (rem--) {
			printf(" %02x", *ioctl_argp++);
		}
		printf("\n");
	}
	free(ioctl_args);
	close(fd);
	return 0;
}