u-boot/include/vxworks.h
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

53 lines
1.6 KiB
C

/*
* (C) Copyright 2008
* Niklaus Giger, niklaus.giger@member.fsf.org
*
* 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
*/
#ifndef _VXWORKS_H_
#define _VXWORKS_H_
int do_bootvx(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
/*
* Use bootaddr to find the location in memory that VxWorks
* will look for the bootline string. The default value for
* PowerPC is LOCAL_MEM_LOCAL_ADRS + BOOT_LINE_OFFSET which
* defaults to 0x4200
*/
#ifndef CONFIG_SYS_VXWORKS_BOOT_ADDR
#define CONFIG_SYS_VXWORKS_BOOT_ADDR 0x4200
#endif
#ifndef CONFIG_SYS_VXWORKS_BOOT_DEVICE
#if defined(CONFIG_4xx)
#define CONFIG_SYS_VXWORKS_BOOT_DEVICE "emac(0,0)"
#elif defined(CONFIG_IOP480)
#define CONFIG_SYS_VXWORKS_BOOT_DEVICE "dc(0,0)"
#else
#define CONFIG_SYS_VXWORKS_BOOT_DEVICE "eth(0,0)"
#endif
#endif
#ifndef CONFIG_SYS_VXWORKS_SERVERNAME
#define CONFIG_SYS_VXWORKS_SERVERNAME "srv"
#endif
#endif