u-boot/board/mpl/pip405/cmd_pip405.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

69 lines
1.9 KiB
C

/*
* (C) Copyright 2001
* Denis Peter, MPL AG Switzerland, d.peter@mpl.ch
*
* 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
*
* hacked for PIP405
*/
#include <common.h>
#include <command.h>
#include "pip405.h"
#include "../common/common_util.h"
extern void print_pip405_info(void);
extern int do_mplcommon(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
/* ------------------------------------------------------------------------- */
int do_pip405(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong led_on,led_nr;
if (strcmp(argv[1], "info") == 0)
{
print_pip405_info();
return 0;
}
if (strcmp(argv[1], "led") == 0)
{
led_nr = (ulong)simple_strtoul(argv[2], NULL, 10);
led_on = (ulong)simple_strtoul(argv[3], NULL, 10);
if(!led_nr)
user_led0(led_on);
else
user_led1(led_on);
return 0;
}
return (do_mplcommon(cmdtp, flag, argc, argv));
}
U_BOOT_CMD(
pip405, 6, 1, do_pip405,
"PIP405 specific Cmds",
"flash mem [SrcAddr] - updates U-Boot with image in memory\n"
"pip405 flash floppy [SrcAddr] - updates U-Boot with image from floppy\n"
"pip405 flash mps - updates U-Boot with image from MPS"
);
/* ------------------------------------------------------------------------- */