mirror of
https://github.com/AsahiLinux/u-boot
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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>
163 lines
3.5 KiB
C
163 lines
3.5 KiB
C
/*
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* (C) Copyright 2003
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* Marc Singer, elf@buici.com
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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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/*
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* Port I/O Functions
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*
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* Copied from FADS ROM, Dan Malek (dmalek@jlc.net)
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*/
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#include <common.h>
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#include <command.h>
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/* Display values from last command.
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* Memory modify remembered values are different from display memory.
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*/
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static uint in_last_addr, in_last_size;
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static uint out_last_addr, out_last_size, out_last_value;
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int do_portio_out (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
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{
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uint addr = out_last_addr;
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uint size = out_last_size;
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uint value = out_last_value;
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if (argc != 3) {
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cmd_usage(cmdtp);
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return 1;
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}
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if ((flag & CMD_FLAG_REPEAT) == 0) {
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/* New command specified. Check for a size specification.
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* Defaults to long if no or incorrect specification.
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*/
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size = cmd_get_data_size (argv[0], 1);
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addr = simple_strtoul (argv[1], NULL, 16);
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value = simple_strtoul (argv[2], NULL, 16);
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}
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#if defined (CONFIG_X86)
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{
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unsigned short port = addr;
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switch (size) {
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default:
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case 1:
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{
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unsigned char ch = value;
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__asm__ volatile ("out %0, %%dx"::"a" (ch), "d" (port));
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}
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break;
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case 2:
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{
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unsigned short w = value;
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__asm__ volatile ("out %0, %%dx"::"a" (w), "d" (port));
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}
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break;
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case 4:
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__asm__ volatile ("out %0, %%dx"::"a" (value), "d" (port));
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break;
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}
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}
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#endif /* CONFIG_X86 */
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out_last_addr = addr;
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out_last_size = size;
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out_last_value = value;
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return 0;
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}
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U_BOOT_CMD(
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out, 3, 1, do_portio_out,
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"write datum to IO port",
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"[.b, .w, .l] port value\n - output to IO port"
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);
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int do_portio_in (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
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{
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uint addr = in_last_addr;
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uint size = in_last_size;
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if (argc != 2) {
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cmd_usage(cmdtp);
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return 1;
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}
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if ((flag & CMD_FLAG_REPEAT) == 0) {
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/* New command specified. Check for a size specification.
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* Defaults to long if no or incorrect specification.
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*/
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size = cmd_get_data_size (argv[0], 1);
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addr = simple_strtoul (argv[1], NULL, 16);
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}
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#if defined (CONFIG_X86)
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{
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unsigned short port = addr;
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switch (size) {
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default:
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case 1:
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{
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unsigned char ch;
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__asm__ volatile ("in %%dx, %0":"=a" (ch):"d" (port));
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printf (" %02x\n", ch);
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}
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break;
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case 2:
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{
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unsigned short w;
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__asm__ volatile ("in %%dx, %0":"=a" (w):"d" (port));
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printf (" %04x\n", w);
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}
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break;
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case 4:
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{
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unsigned long l;
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__asm__ volatile ("in %%dx, %0":"=a" (l):"d" (port));
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printf (" %08lx\n", l);
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}
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break;
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}
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}
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#endif /* CONFIG_X86 */
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in_last_addr = addr;
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in_last_size = size;
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return 0;
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}
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U_BOOT_CMD(
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in, 2, 1, do_portio_in,
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"read data from an IO port",
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"[.b, .w, .l] port\n"
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" - read datum from IO port"
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);
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