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>
diff --git a/board/cm5200/cmd_cm5200.c b/board/cm5200/cmd_cm5200.c
index cd98ae2..df372d9 100644
--- a/board/cm5200/cmd_cm5200.c
+++ b/board/cm5200/cmd_cm5200.c
@@ -29,7 +29,7 @@
#ifdef CONFIG_CMD_BSP
-static int do_i2c_test(char *argv[])
+static int do_i2c_test(char * const argv[])
{
unsigned char temp, temp1;
@@ -57,7 +57,7 @@
return 0;
}
-static int do_usb_test(char *argv[])
+static int do_usb_test(char * const argv[])
{
int i;
static int usb_stor_curr_dev = -1; /* current device */
@@ -90,7 +90,7 @@
return 0;
}
-static int do_led_test(char *argv[])
+static int do_led_test(char * const argv[])
{
int i = 0;
struct mpc5xxx_gpt_0_7 *gpt = (struct mpc5xxx_gpt_0_7 *)MPC5XXX_GPT;
@@ -134,7 +134,7 @@
return 0;
}
-static int do_rs232_test(char *argv[])
+static int do_rs232_test(char * const argv[])
{
int error_status = 0;
struct mpc5xxx_gpio *gpio = (struct mpc5xxx_gpio *)MPC5XXX_GPIO;
@@ -397,7 +397,7 @@
return error_status;
}
-static int cmd_fkt(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int cmd_fkt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int rcode = -1;