u-boot/board/tqc/tqm5200/cmd_tb5200.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

104 lines
2.5 KiB
C

/*
* (C) Copyright 2005 - 2006
* Martin Krause, TQ-Systems GmbH, martin.krause@tqs.de.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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
*/
/*
* TB5200 specific functions
*/
/*#define DEBUG*/
#include <common.h>
#include <command.h>
#if defined(CONFIG_CMD_BSP)
#if defined (CONFIG_TB5200)
#define SM501_PANEL_DISPLAY_CONTROL 0x00080000UL
static void led_init(void)
{
struct mpc5xxx_gpt_0_7 *gpt = (struct mpc5xxx_gpt_0_7 *)MPC5XXX_GPT;
/* configure timer 4 for simple GPIO output */
gpt->gpt4.emsr |= 0x00000024;
}
int cmd_led(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
struct mpc5xxx_gpt_0_7 *gpt = (struct mpc5xxx_gpt_0_7 *)MPC5XXX_GPT;
led_init();
if (strcmp (argv[1], "on") == 0) {
debug ("switch status LED on\n");
gpt->gpt4.emsr |= (1 << 4);
} else if (strcmp (argv[1], "off") == 0) {
debug ("switch status LED off\n");
gpt->gpt4.emsr &= ~(1 << 4);
} else {
printf ("Usage:\nled on/off\n");
return 1;
}
return 0;
}
static void sm501_backlight (unsigned int state)
{
if (state == 1) {
*(vu_long *)(SM501_MMIO_BASE+SM501_PANEL_DISPLAY_CONTROL) |=
(1 << 26) | (1 << 27);
} else if (state == 0)
*(vu_long *)(SM501_MMIO_BASE+SM501_PANEL_DISPLAY_CONTROL) &=
~((1 << 26) | (1 << 27));
}
int cmd_backlight(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
if (strcmp (argv[1], "on") == 0) {
debug ("switch backlight on\n");
sm501_backlight (1);
} else if (strcmp (argv[1], "off") == 0) {
debug ("switch backlight off\n");
sm501_backlight (0);
} else {
printf ("Usage:\nbacklight on/off\n");
return 1;
}
return 0;
}
U_BOOT_CMD(
led , 2, 1, cmd_led,
"switch status LED on or off",
"on/off"
);
U_BOOT_CMD(
backlight , 2, 1, cmd_backlight,
"switch backlight on or off",
"on/off"
);
#endif /* CONFIG_STK52XX */
#endif