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u-boot/board/lwmon5/kbd.c
Wolfgang Denk 54841ab50c Make sure that argv[] argument pointers are not modified. 
The hush shell dynamically allocates (and re-allocates) memory for the
argument strings in the "char *argv[]" argument vector passed to
commands.  Any code that modifies these pointers will cause serious
corruption of the malloc data structures and crash U-Boot, so make
sure the compiler can check that no such modifications are being done
by changing the code into "char * const argv[]".

This modification is the result of debugging a strange crash caused
after adding a new command, which used the following argument
processing code which has been working perfectly fine in all Unix
systems since version 6 - but not so in U-Boot:

int main (int argc, char **argv)
{
	while (--argc > 0 && **++argv == '-') {
/* ====> */	while (*++*argv) {
			switch (**argv) {
			case 'd':
				debug++;
				break;
			...
			default:
				usage ();
			}
		}
	}
	...
}

The line marked "====>" will corrupt the malloc data structures and
usually cause U-Boot to crash when the next command gets executed by
the shell.  With the modification, the compiler will prevent this with
an
	error: increment of read-only location '*argv'

N.B.: The code above can be trivially rewritten like this:

	while (--argc > 0 && **++argv == '-') {
		char *arg = *argv;
		while (*++arg) {
			switch (*arg) {
			...

Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
2010-07-04 23:55:42 +02:00

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/*
* (C) Copyright 2007
* Stefan Roese, DENX Software Engineering, sr@denx.de.
*
* (C) Copyright 2001, 2002
* DENX Software Engineering
* Wolfgang Denk, wd@denx.de
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/* define DEBUG for debugging output (obviously ;-)) */
#if 0
#define DEBUG
#endif
#include <common.h>
#include <i2c.h>
#include <command.h>
#include <post.h>
#include <serial.h>
#include <malloc.h>
#include <linux/types.h>
#include <linux/string.h> /* for strdup */
DECLARE_GLOBAL_DATA_PTR;
static void kbd_init (void);
static int compare_magic (uchar *kbd_data, uchar *str);
/*--------------------- Local macros and constants --------------------*/
#define _NOT_USED_ 0xFFFFFFFF
/*------------------------- Keyboard controller -----------------------*/
/* command codes */
#define KEYBD_CMD_READ_KEYS 0x01
#define KEYBD_CMD_READ_VERSION 0x02
#define KEYBD_CMD_READ_STATUS 0x03
#define KEYBD_CMD_RESET_ERRORS 0x10
/* status codes */
#define KEYBD_STATUS_MASK 0x3F
#define KEYBD_STATUS_H_RESET 0x20
#define KEYBD_STATUS_BROWNOUT 0x10
#define KEYBD_STATUS_WD_RESET 0x08
#define KEYBD_STATUS_OVERLOAD 0x04
#define KEYBD_STATUS_ILLEGAL_WR 0x02
#define KEYBD_STATUS_ILLEGAL_RD 0x01
/* Number of bytes returned from Keyboard Controller */
#define KEYBD_VERSIONLEN 2 /* version information */
/*
* This is different from the "old" lwmon dsPIC kbd controller
* implementation. Now the controller still answers with 9 bytes,
* but the last 3 bytes are always "0x06 0x07 0x08". So we just
* set the length to compare to 6 instead of 9.
*/
#define KEYBD_DATALEN 6 /* normal key scan data */
/* maximum number of "magic" key codes that can be assigned */
static uchar kbd_addr = CONFIG_SYS_I2C_KEYBD_ADDR;
static uchar *key_match (uchar *);
#define KEYBD_SET_DEBUGMODE '#' /* Magic key to enable debug output */
/***********************************************************************
F* Function: int board_postclk_init (void) P*A*Z*
*
P* Parameters: none
P*
P* Returnvalue: int
P* - 0 is always returned.
*
Z* Intention: This function is the board_postclk_init() method implementation
Z* for the lwmon board.
*
***********************************************************************/
int board_postclk_init (void)
{
kbd_init();
return (0);
}
static void kbd_init (void)
{
uchar kbd_data[KEYBD_DATALEN];
uchar tmp_data[KEYBD_DATALEN];
uchar val, errcd;
int i;
i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
gd->kbd_status = 0;
/* Forced by PIC. Delays <= 175us loose */
udelay(1000);
/* Read initial keyboard error code */
val = KEYBD_CMD_READ_STATUS;
i2c_write (kbd_addr, 0, 0, &val, 1);
i2c_read (kbd_addr, 0, 0, &errcd, 1);
/* clear unused bits */
errcd &= KEYBD_STATUS_MASK;
/* clear "irrelevant" bits. Recommended by Martin Rajek, LWN */
errcd &= ~(KEYBD_STATUS_H_RESET|KEYBD_STATUS_BROWNOUT);
if (errcd) {
gd->kbd_status |= errcd << 8;
}
/* Reset error code and verify */
val = KEYBD_CMD_RESET_ERRORS;
i2c_write (kbd_addr, 0, 0, &val, 1);
udelay(1000); /* delay NEEDED by keyboard PIC !!! */
val = KEYBD_CMD_READ_STATUS;
i2c_write (kbd_addr, 0, 0, &val, 1);
i2c_read (kbd_addr, 0, 0, &val, 1);
val &= KEYBD_STATUS_MASK; /* clear unused bits */
if (val) { /* permanent error, report it */
gd->kbd_status |= val;
return;
}
/*
* Read current keyboard state.
*
* After the error reset it may take some time before the
* keyboard PIC picks up a valid keyboard scan - the total
* scan time is approx. 1.6 ms (information by Martin Rajek,
* 28 Sep 2002). We read a couple of times for the keyboard
* to stabilize, using a big enough delay.
* 10 times should be enough. If the data is still changing,
* we use what we get :-(
*/
memset (tmp_data, 0xFF, KEYBD_DATALEN); /* impossible value */
for (i=0; i<10; ++i) {
val = KEYBD_CMD_READ_KEYS;
i2c_write (kbd_addr, 0, 0, &val, 1);
i2c_read (kbd_addr, 0, 0, kbd_data, KEYBD_DATALEN);
if (memcmp(kbd_data, tmp_data, KEYBD_DATALEN) == 0) {
/* consistent state, done */
break;
}
/* remeber last state, delay, and retry */
memcpy (tmp_data, kbd_data, KEYBD_DATALEN);
udelay (5000);
}
}
/***********************************************************************
F* Function: int misc_init_r (void) P*A*Z*
*
P* Parameters: none
P*
P* Returnvalue: int
P* - 0 is always returned, even in the case of a keyboard
P* error.
*
Z* Intention: This function is the misc_init_r() method implementation
Z* for the lwmon board.
Z* The keyboard controller is initialized and the result
Z* of a read copied to the environment variable "keybd".
Z* If KEYBD_SET_DEBUGMODE is defined, a check is made for
Z* this key, and if found display to the LCD will be enabled.
Z* The keys in "keybd" are checked against the magic
Z* keycommands defined in the environment.
Z* See also key_match().
*
D* Design: wd@denx.de
C* Coding: wd@denx.de
V* Verification: dzu@denx.de
***********************************************************************/
int misc_init_r_kbd (void)
{
uchar kbd_data[KEYBD_DATALEN];
char keybd_env[2 * KEYBD_DATALEN + 1];
uchar kbd_init_status = gd->kbd_status >> 8;
uchar kbd_status = gd->kbd_status;
uchar val;
char *str;
int i;
if (kbd_init_status) {
printf ("KEYBD: Error %02X\n", kbd_init_status);
}
if (kbd_status) { /* permanent error, report it */
printf ("*** Keyboard error code %02X ***\n", kbd_status);
sprintf (keybd_env, "%02X", kbd_status);
setenv ("keybd", keybd_env);
return 0;
}
/*
* Now we know that we have a working keyboard, so disable
* all output to the LCD except when a key press is detected.
*/
if ((console_assign (stdout, "serial") < 0) ||
(console_assign (stderr, "serial") < 0)) {
printf ("Can't assign serial port as output device\n");
}
/* Read Version */
val = KEYBD_CMD_READ_VERSION;
i2c_write (kbd_addr, 0, 0, &val, 1);
i2c_read (kbd_addr, 0, 0, kbd_data, KEYBD_VERSIONLEN);
printf ("KEYBD: Version %d.%d\n", kbd_data[0], kbd_data[1]);
/* Read current keyboard state */
val = KEYBD_CMD_READ_KEYS;
i2c_write (kbd_addr, 0, 0, &val, 1);
i2c_read (kbd_addr, 0, 0, kbd_data, KEYBD_DATALEN);
for (i = 0; i < KEYBD_DATALEN; ++i) {
sprintf (keybd_env + i + i, "%02X", kbd_data[i]);
}
setenv ("keybd", keybd_env);
str = strdup ((char *)key_match (kbd_data)); /* decode keys */
#ifdef KEYBD_SET_DEBUGMODE
if (kbd_data[0] == KEYBD_SET_DEBUGMODE) { /* set debug mode */
if ((console_assign (stdout, "lcd") < 0) ||
(console_assign (stderr, "lcd") < 0)) {
printf ("Can't assign LCD display as output device\n");
}
}
#endif /* KEYBD_SET_DEBUGMODE */
#ifdef CONFIG_PREBOOT /* automatically configure "preboot" command on key match */
setenv ("preboot", str); /* set or delete definition */
#endif /* CONFIG_PREBOOT */
if (str != NULL) {
free (str);
}
return (0);
}
#ifdef CONFIG_PREBOOT
static uchar kbd_magic_prefix[] = "key_magic";
static uchar kbd_command_prefix[] = "key_cmd";
static int compare_magic (uchar *kbd_data, uchar *str)
{
uchar compare[KEYBD_DATALEN-1];
char *nxt;
int i;
/* Don't include modifier byte */
memcpy (compare, kbd_data+1, KEYBD_DATALEN-1);
for (; str != NULL; str = (*nxt) ? (uchar *)(nxt+1) : (uchar *)nxt) {
uchar c;
int k;
c = (uchar) simple_strtoul ((char *)str, (char **) (&nxt), 16);
if (str == (uchar *)nxt) { /* invalid character */
break;
}
/*
* Check if this key matches the input.
* Set matches to zero, so they match only once
* and we can find duplicates or extra keys
*/
for (k = 0; k < sizeof(compare); ++k) {
if (compare[k] == '\0') /* only non-zero entries */
continue;
if (c == compare[k]) { /* found matching key */
compare[k] = '\0';
break;
}
}
if (k == sizeof(compare)) {
return -1; /* unmatched key */
}
}
/*
* A full match leaves no keys in the `compare' array,
*/
for (i = 0; i < sizeof(compare); ++i) {
if (compare[i])
{
return -1;
}
}
return 0;
}
/***********************************************************************
F* Function: static uchar *key_match (uchar *kbd_data) P*A*Z*
*
P* Parameters: uchar *kbd_data
P* - The keys to match against our magic definitions
P*
P* Returnvalue: uchar *
P* - != NULL: Pointer to the corresponding command(s)
P* NULL: No magic is about to happen
*
Z* Intention: Check if pressed key(s) match magic sequence,
Z* and return the command string associated with that key(s).
Z*
Z* If no key press was decoded, NULL is returned.
Z*
Z* Note: the first character of the argument will be
Z* overwritten with the "magic charcter code" of the
Z* decoded key(s), or '\0'.
Z*
Z* Note: the string points to static environment data
Z* and must be saved before you call any function that
Z* modifies the environment.
*
D* Design: wd@denx.de
C* Coding: wd@denx.de
V* Verification: dzu@denx.de
***********************************************************************/
static uchar *key_match (uchar *kbd_data)
{
char magic[sizeof (kbd_magic_prefix) + 1];
uchar *suffix;
char *kbd_magic_keys;
/*
* The following string defines the characters that can pe appended
* to "key_magic" to form the names of environment variables that
* hold "magic" key codes, i. e. such key codes that can cause
* pre-boot actions. If the string is empty (""), then only
* "key_magic" is checked (old behaviour); the string "125" causes
* checks for "key_magic1", "key_magic2" and "key_magic5", etc.
*/
if ((kbd_magic_keys = getenv ("magic_keys")) == NULL)
kbd_magic_keys = "";
/* loop over all magic keys;
* use '\0' suffix in case of empty string
*/
for (suffix=(uchar *)kbd_magic_keys; *suffix || suffix==(uchar *)kbd_magic_keys; ++suffix) {
sprintf (magic, "%s%c", kbd_magic_prefix, *suffix);
debug ("### Check magic \"%s\"\n", magic);
if (compare_magic(kbd_data, (uchar *)getenv(magic)) == 0) {
char cmd_name[sizeof (kbd_command_prefix) + 1];
char *cmd;
sprintf (cmd_name, "%s%c", kbd_command_prefix, *suffix);
cmd = getenv (cmd_name);
debug ("### Set PREBOOT to $(%s): \"%s\"\n",
cmd_name, cmd ? cmd : "<<NULL>>");
*kbd_data = *suffix;
return ((uchar *)cmd);
}
}
debug ("### Delete PREBOOT\n");
*kbd_data = '\0';
return (NULL);
}
#endif /* CONFIG_PREBOOT */
/***********************************************************************
F* Function: int do_kbd (cmd_tbl_t *cmdtp, int flag,
F* int argc, char * const argv[]) P*A*Z*
*
P* Parameters: cmd_tbl_t *cmdtp
P* - Pointer to our command table entry
P* int flag
P* - If the CMD_FLAG_REPEAT bit is set, then this call is
P* a repetition
P* int argc
P* - Argument count
P* char * const argv[]
P* - Array of the actual arguments
P*
P* Returnvalue: int
P* - 0 is always returned.
*
Z* Intention: Implement the "kbd" command.
Z* The keyboard status is read. The result is printed on
Z* the console and written into the "keybd" environment
Z* variable.
*
D* Design: wd@denx.de
C* Coding: wd@denx.de
V* Verification: dzu@denx.de
***********************************************************************/
int do_kbd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
uchar kbd_data[KEYBD_DATALEN];
char keybd_env[2 * KEYBD_DATALEN + 1];
uchar val;
int i;
#if 0 /* Done in kbd_init */
i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
#endif
/* Read keys */
val = KEYBD_CMD_READ_KEYS;
i2c_write (kbd_addr, 0, 0, &val, 1);
i2c_read (kbd_addr, 0, 0, kbd_data, KEYBD_DATALEN);
puts ("Keys:");
for (i = 0; i < KEYBD_DATALEN; ++i) {
sprintf (keybd_env + i + i, "%02X", kbd_data[i]);
printf (" %02x", kbd_data[i]);
}
putc ('\n');
setenv ("keybd", keybd_env);
return 0;
}
U_BOOT_CMD(
kbd, 1, 1, do_kbd,
"read keyboard status",
""
);
/*----------------------------- Utilities -----------------------------*/
#ifdef CONFIG_POST
/*
* Returns 1 if keys pressed to start the power-on long-running tests
* Called from board_init_f().
*/
int post_hotkeys_pressed(void)
{
uchar kbd_data[KEYBD_DATALEN];
uchar val;
/* Read keys */
val = KEYBD_CMD_READ_KEYS;
i2c_write (kbd_addr, 0, 0, &val, 1);
i2c_read (kbd_addr, 0, 0, kbd_data, KEYBD_DATALEN);
return (compare_magic(kbd_data, (uchar *)CONFIG_POST_KEY_MAGIC) == 0);
}
#endif
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