u-boot-brain/common/cmd_dcr.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

246 lines
6.8 KiB
C

/*
* (C) Copyright 2001
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
*
* 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
*/
/*
* AMCC 4XX DCR Functions
*/
#include <common.h>
#include <config.h>
#include <command.h>
unsigned long get_dcr (unsigned short);
unsigned long set_dcr (unsigned short, unsigned long);
/* =======================================================================
* Interpreter command to retrieve an AMCC PPC 4xx Device Control Register
* =======================================================================
*/
int do_getdcr ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[] )
{
unsigned short dcrn; /* Device Control Register Num */
unsigned long value; /* DCR's value */
unsigned long get_dcr (unsigned short);
/* Validate arguments */
if (argc < 2) {
cmd_usage(cmdtp);
return 1;
}
/* Get a DCR */
dcrn = (unsigned short) simple_strtoul (argv[1], NULL, 16);
value = get_dcr (dcrn);
printf ("%04x: %08lx\n", dcrn, value);
return 0;
}
/* ======================================================================
* Interpreter command to set an AMCC PPC 4xx Device Control Register
* ======================================================================
*/
int do_setdcr (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned short dcrn; /* Device Control Register Num */
unsigned long value;
/* DCR's value */
int nbytes;
extern char console_buffer[];
/* Validate arguments */
if (argc < 2) {
cmd_usage(cmdtp);
return 1;
}
/* Set a DCR */
dcrn = (unsigned short) simple_strtoul (argv[1], NULL, 16);
do {
value = get_dcr (dcrn);
printf ("%04x: %08lx", dcrn, value);
nbytes = readline (" ? ");
if (nbytes == 0) {
/*
* <CR> pressed as only input, don't modify current
* location and exit command.
*/
nbytes = 1;
return 0;
} else {
unsigned long i;
char *endp;
i = simple_strtoul (console_buffer, &endp, 16);
nbytes = endp - console_buffer;
if (nbytes)
set_dcr (dcrn, i);
}
} while (nbytes);
return 0;
}
/* =======================================================================
* Interpreter command to retrieve an register value through AMCC PPC 4xx
* Device Control Register inderect addressing.
* =======================================================================
*/
int do_getidcr (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
unsigned short adr_dcrn; /* Device Control Register Num for Address */
unsigned short dat_dcrn; /* Device Control Register Num for Data */
unsigned short offset; /* Register's offset */
unsigned long value; /* Register's value */
char *ptr = NULL;
char buf[80];
/* Validate arguments */
if (argc < 3) {
cmd_usage(cmdtp);
return 1;
}
/* Find out whether ther is '.' (dot) symbol in the first parameter. */
strncpy (buf, argv[1], sizeof(buf)-1);
buf[sizeof(buf)-1] = 0; /* will guarantee zero-end string */
ptr = strchr (buf, '.');
if (ptr != NULL) {
/* First parameter has format adr_dcrn.dat_dcrn */
*ptr++ = 0; /* erase '.', create zero-end string */
adr_dcrn = (unsigned short) simple_strtoul (buf, NULL, 16);
dat_dcrn = (unsigned short) simple_strtoul (ptr, NULL, 16);
} else {
/*
* First parameter has format adr_dcrn; dat_dcrn will be
* calculated as adr_dcrn+1.
*/
adr_dcrn = (unsigned short) simple_strtoul (buf, NULL, 16);
dat_dcrn = adr_dcrn+1;
}
/* Register's offset */
offset = (unsigned short) simple_strtoul (argv[2], NULL, 16);
/* Disable interrupts */
disable_interrupts ();
/* Set offset */
set_dcr (adr_dcrn, offset);
/* get data */
value = get_dcr (dat_dcrn);
/* Enable interrupts */
enable_interrupts ();
printf ("%04x.%04x-%04x Read %08lx\n", adr_dcrn, dat_dcrn, offset, value);
return 0;
}
/* =======================================================================
* Interpreter command to update an register value through AMCC PPC 4xx
* Device Control Register inderect addressing.
* =======================================================================
*/
int do_setidcr (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned short adr_dcrn; /* Device Control Register Num for Address */
unsigned short dat_dcrn; /* Device Control Register Num for Data */
unsigned short offset; /* Register's offset */
unsigned long value; /* Register's value */
char *ptr = NULL;
char buf[80];
/* Validate arguments */
if (argc < 4) {
cmd_usage(cmdtp);
return 1;
}
/* Find out whether ther is '.' (dot) symbol in the first parameter. */
strncpy (buf, argv[1], sizeof(buf)-1);
buf[sizeof(buf)-1] = 0; /* will guarantee zero-end string */
ptr = strchr (buf, '.');
if (ptr != NULL) {
/* First parameter has format adr_dcrn.dat_dcrn */
*ptr++ = 0; /* erase '.', create zero-end string */
adr_dcrn = (unsigned short) simple_strtoul (buf, NULL, 16);
dat_dcrn = (unsigned short) simple_strtoul (ptr, NULL, 16);
} else {
/*
* First parameter has format adr_dcrn; dat_dcrn will be
* calculated as adr_dcrn+1.
*/
adr_dcrn = (unsigned short) simple_strtoul (buf, NULL, 16);
dat_dcrn = adr_dcrn+1;
}
/* Register's offset */
offset = (unsigned short) simple_strtoul (argv[2], NULL, 16);
/* New value */
value = (unsigned long) simple_strtoul (argv[3], NULL, 16);
/* Disable interrupts */
disable_interrupts ();
/* Set offset */
set_dcr (adr_dcrn, offset);
/* set data */
set_dcr (dat_dcrn, value);
/* Enable interrupts */
enable_interrupts ();
printf ("%04x.%04x-%04x Write %08lx\n", adr_dcrn, dat_dcrn, offset, value);
return 0;
}
/***************************************************/
U_BOOT_CMD(
getdcr, 2, 1, do_getdcr,
"Get an AMCC PPC 4xx DCR's value",
"dcrn - return a DCR's value."
);
U_BOOT_CMD(
setdcr, 2, 1, do_setdcr,
"Set an AMCC PPC 4xx DCR's value",
"dcrn - set a DCR's value."
);
U_BOOT_CMD(
getidcr, 3, 1, do_getidcr,
"Get a register value via indirect DCR addressing",
"adr_dcrn[.dat_dcrn] offset - write offset to adr_dcrn, read value from dat_dcrn."
);
U_BOOT_CMD(
setidcr, 4, 1, do_setidcr,
"Set a register value via indirect DCR addressing",
"adr_dcrn[.dat_dcrn] offset value - write offset to adr_dcrn, write value to dat_dcrn."
);