From 54841ab50c20d6fa6c9cc3eb826989da3a22d934 Mon Sep 17 00:00:00 2001
From: Wolfgang Denk <wd@denx.de>
Date: Mon, 28 Jun 2010 22:00:46 +0200
Subject: 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>
---
board/esd/pmc405de/pmc405de.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
(limited to 'board/esd/pmc405de')
diff --git a/board/esd/pmc405de/pmc405de.c b/board/esd/pmc405de/pmc405de.c
index 3725ece394..b84e08ad72 100644
--- a/board/esd/pmc405de/pmc405de.c
+++ b/board/esd/pmc405de/pmc405de.c
@@ -374,7 +374,7 @@ int eeprom_write_enable(unsigned dev_addr, int state)
return state;
}
-int do_eep_wren(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_eep_wren(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int query = argc == 1;
int state = 0;
@@ -417,7 +417,7 @@ U_BOOT_CMD(eepwren, 2, 0, do_eep_wren,
#include <environment.h>
extern env_t *env_ptr;
-int do_painit(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_painit(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
u32 pram, nextbase, base;
char *v;
@@ -477,7 +477,7 @@ U_BOOT_CMD(
);
#endif /* CONFIG_PRAM */
-int do_selfreset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_selfreset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
struct ppc4xx_gpio *gpio0 = (struct ppc4xx_gpio *)GPIO_BASE;
setbits_be32(&gpio0->tcr, CONFIG_SYS_GPIO_SELFRST_N);
@@ -489,7 +489,7 @@ U_BOOT_CMD(
""
);
-int do_resetout(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_resetout(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
struct pmc405de_cpld *cpld =
(struct pmc405de_cpld *)CONFIG_SYS_CPLD_BASE;
--
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