bdisk/extra/external/SMC_DumpKey/SmcDumpKey.c

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/*
* prints out 4-character name of the SMC key at given index position;
*
* by Gabriel L. Somlo <somlo@cmu.edu>, Summer 2014
*
* Compile with: gcc -O2 -o SmcDumpKey SmcDumpKey.c -Wall
*
* You probably want to "modprobe -r applesmc" before running this...
*
* Code bits and pieces shamelessly ripped from the linux kernel driver
* (drivers/hwmon/applesmc.c by N. Boichat and H. Rydberg)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License v2 as published by the
* Free Software Foundation.
*
* 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <limits.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <sys/io.h>
#include <linux/byteorder/little_endian.h>
#define APPLESMC_START 0x300
#define APPLESMC_RANGE 0x20
#define APPLESMC_DATA_PORT (APPLESMC_START + 0x00)
#define APPLESMC_CMD_PORT (APPLESMC_START + 0x04)
#define APPLESMC_READ_CMD 0x10
#define APPLESMC_GET_KEY_BY_INDEX_CMD 0x12
#define APPLESMC_GET_KEY_TYPE_CMD 0x13
/* wait up to 128 ms for a status change. */
#define APPLESMC_MIN_WAIT 0x0010
#define APPLESMC_RETRY_WAIT 0x0100
#define APPLESMC_MAX_WAIT 0x20000
#define APPLESMC_KEY_NAME_LEN 4
#define APPLESMC_KEY_TYPE_LEN 4
typedef struct key_type {
uint8_t data_len;
uint8_t data_type[APPLESMC_KEY_TYPE_LEN];
uint8_t flags;
} __attribute__((packed)) key_type;
/* wait_read - Wait for a byte to appear on SMC port. */
static int
wait_read(void)
{
uint8_t status;
int us;
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
usleep(us);
status = inb(APPLESMC_CMD_PORT);
/* read: wait for smc to settle */
if (status & 0x01)
return 0;
}
fprintf(stderr, "wait_read() fail: 0x%02x\n", status);
return -1;
}
/*send_byte - Write to SMC port, retrying when necessary. */
static int
send_byte(uint8_t cmd, unsigned short port)
{
uint8_t status;
int us;
outb(cmd, port);
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
usleep(us);
status = inb(APPLESMC_CMD_PORT);
/* write: wait for smc to settle */
if (status & 0x02)
continue;
/* ready: cmd accepted, return */
if (status & 0x04)
return 0;
/* timeout: give up */
if (us << 1 == APPLESMC_MAX_WAIT)
break;
/* busy: long wait and resend */
usleep(APPLESMC_RETRY_WAIT);
outb(cmd, port);
}
fprintf(stderr,
"send_byte(0x%02x, 0x%04x) fail: 0x%02x\n", cmd, port, status);
return -1;
}
static int
send_argument(const uint8_t *key)
{
int i;
for (i = 0; i < APPLESMC_KEY_NAME_LEN; i++)
if (send_byte(key[i], APPLESMC_DATA_PORT))
return -1;
return 0;
}
static int
read_smc(uint8_t cmd, const uint8_t *key, uint8_t *buf, uint8_t len)
{
int i;
if (send_byte(cmd, APPLESMC_CMD_PORT) || send_argument(key)) {
fprintf(stderr, "%.4s: read arg fail\n", key);
return -1;
}
if (send_byte(len, APPLESMC_DATA_PORT)) {
fprintf(stderr, "%.4s: read len fail\n", key);
return -1;
}
for (i = 0; i < len; i++) {
if (wait_read()) {
fprintf(stderr, "%.4s: read data[%d] fail\n", key, i);
return -1;
}
buf[i] = inb(APPLESMC_DATA_PORT);
}
return 0;
}
int
main(int argc, char **argv)
{
key_type kt;
uint8_t data_buf[UCHAR_MAX];
uint8_t i;
if (argc != 2 || strlen(argv[1]) != APPLESMC_KEY_NAME_LEN) {
fprintf(stderr, "\nUsage: %s <4-char-key-name>\n\n", argv[0]);
return -1;
}
if (ioperm(APPLESMC_START, APPLESMC_RANGE, 1) != 0) {
perror("ioperm failed");
return -2;
}
if (read_smc(APPLESMC_GET_KEY_TYPE_CMD,
(uint8_t *)argv[1], (uint8_t *)&kt, sizeof(kt)) != 0) {
fprintf(stderr, "\nread_smc get_key_type error\n\n");
return -3;
}
printf(" type=\"");
for (i = 0; i < APPLESMC_KEY_TYPE_LEN; i++)
printf(isprint(kt.data_type[i]) ? "%c" : "\\x%02x",
(uint8_t)kt.data_type[i]);
printf("\" length=%d flags=%x\n", kt.data_len, kt.flags);
if (read_smc(APPLESMC_READ_CMD,
(uint8_t *)argv[1], data_buf, kt.data_len) != 0) {
fprintf(stderr, "\nread_smc get_key_data error\n\n");
return -4;
}
printf(" data=\"");
for (i = 0; i < kt.data_len; i++)
printf(isprint(data_buf[i]) ? "%c" : "\\x%02x",
(uint8_t)data_buf[i]);
printf("\"\n");
return 0;
}