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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>
70 lines
1.9 KiB
C
70 lines
1.9 KiB
C
/*
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* (C) Copyright 2001
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* Denis Peter, MPL AG Switzerland, d.peter@mpl.ch
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*
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* hacked for PIP405
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*/
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#include <common.h>
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#include <command.h>
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#include "pip405.h"
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#include "../common/common_util.h"
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extern void print_pip405_info(void);
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extern int do_mplcommon(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
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/* ------------------------------------------------------------------------- */
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int do_pip405(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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ulong led_on,led_nr;
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if (strcmp(argv[1], "info") == 0)
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{
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print_pip405_info();
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return 0;
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}
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if (strcmp(argv[1], "led") == 0)
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{
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led_nr = (ulong)simple_strtoul(argv[2], NULL, 10);
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led_on = (ulong)simple_strtoul(argv[3], NULL, 10);
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if(!led_nr)
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user_led0(led_on);
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else
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user_led1(led_on);
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return 0;
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}
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return (do_mplcommon(cmdtp, flag, argc, argv));
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}
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U_BOOT_CMD(
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pip405, 6, 1, do_pip405,
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"PIP405 specific Cmds",
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"flash mem [SrcAddr] - updates U-Boot with image in memory\n"
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"pip405 flash floppy [SrcAddr] - updates U-Boot with image from floppy\n"
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"pip405 flash mps - updates U-Boot with image from MPS"
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);
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/* ------------------------------------------------------------------------- */
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