mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-08-24 19:08:50 +09:00
![Wolfgang Denk](/assets/img/avatar_default.png)
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>
56 lines
1.4 KiB
C
56 lines
1.4 KiB
C
/*
|
|
* (C) Copyright 2007 by OpenMoko, Inc.
|
|
* Author: Harald Welte <laforge@openmoko.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
|
|
*/
|
|
|
|
#include <common.h>
|
|
|
|
/* COPYING is currently 15951 bytes in size */
|
|
#define LICENSE_MAX 20480
|
|
|
|
#include <command.h>
|
|
#include <malloc.h>
|
|
#include <license.h>
|
|
|
|
int do_license(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
|
|
{
|
|
char *tok, *dst = malloc(LICENSE_MAX);
|
|
unsigned long len = LICENSE_MAX;
|
|
|
|
if (!dst)
|
|
return -1;
|
|
|
|
if (gunzip(dst, LICENSE_MAX, license_gz, &len) != 0) {
|
|
printf("Error uncompressing license text\n");
|
|
free(dst);
|
|
return -1;
|
|
}
|
|
puts(dst);
|
|
free(dst);
|
|
|
|
return 0;
|
|
}
|
|
|
|
U_BOOT_CMD(license, 1, 1, do_license,
|
|
"print GPL license text",
|
|
""
|
|
);
|