mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-10 23:24:38 +00:00
54841ab50c
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>
78 lines
1.9 KiB
C
78 lines
1.9 KiB
C
/*
|
|
* (C) Copyright 2005
|
|
* Wolfgang Denk, DENX Software Engineering, wd@denx.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
|
|
*/
|
|
|
|
#include <common.h>
|
|
#include <command.h>
|
|
|
|
#undef DEBUG_DISP
|
|
|
|
#define DISP_SIZE 8
|
|
#define CWORD_CLEAR 0x80
|
|
#define CLEAR_DELAY (110 * 2)
|
|
|
|
int do_display (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
|
|
{
|
|
int i;
|
|
int pos;
|
|
|
|
/* Clear display */
|
|
*((volatile char*)(CONFIG_SYS_DISP_CWORD)) = CWORD_CLEAR;
|
|
udelay(1000 * CLEAR_DELAY);
|
|
|
|
if (argc < 2)
|
|
return (0);
|
|
|
|
for (pos = 0, i = 1; i < argc && pos < DISP_SIZE; i++) {
|
|
char *p = argv[i], c;
|
|
|
|
if (i > 1) {
|
|
*((volatile uchar *) (CONFIG_SYS_DISP_CHR_RAM + pos++)) = ' ';
|
|
#ifdef DEBUG_DISP
|
|
putc(' ');
|
|
#endif
|
|
}
|
|
|
|
while ((c = *p++) != '\0' && pos < DISP_SIZE) {
|
|
*((volatile uchar *) (CONFIG_SYS_DISP_CHR_RAM + pos++)) = c;
|
|
#ifdef DEBUG_DISP
|
|
putc(c);
|
|
#endif
|
|
}
|
|
}
|
|
|
|
#ifdef DEBUG_DISP
|
|
putc('\n');
|
|
#endif
|
|
|
|
return (0);
|
|
}
|
|
|
|
/***************************************************/
|
|
|
|
U_BOOT_CMD(
|
|
display, CONFIG_SYS_MAXARGS, 1, do_display,
|
|
"display string on dot matrix display",
|
|
"[<string>]\n"
|
|
" - with <string> argument: display <string> on dot matrix display\n"
|
|
" - without arguments: clear dot matrix display"
|
|
);
|