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>

4 files changed, 4 insertions, 4 deletions

diff --git a/arch/powerpc/cpu/mpc83xx/cpu.c b/arch/powerpc/cpu/mpc83xx/cpu.c
index d3be909..b664c64 100644
--- a/arch/powerpc/cpu/mpc83xx/cpu.c
+++ b/arch/powerpc/cpu/mpc83xx/cpu.c
@@ -192,7 +192,7 @@ void upmconfig (uint upm, uint *table, uint size)
 
 
 int
-do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong msr;
 #ifndef MPC83xx_RESET
diff --git a/arch/powerpc/cpu/mpc83xx/ecc.c b/arch/powerpc/cpu/mpc83xx/ecc.c
index f3942b4..8dadd64 100644
--- a/arch/powerpc/cpu/mpc83xx/ecc.c
+++ b/arch/powerpc/cpu/mpc83xx/ecc.c
@@ -98,7 +98,7 @@ void ecc_print_status(void)
 	       ddr->capture_attributes & ECC_CAPT_ATTR_VLD);
 }
 
-int do_ecc(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_ecc(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
 	volatile ddr83xx_t *ddr = &immap->ddr;
diff --git a/arch/powerpc/cpu/mpc83xx/interrupts.c b/arch/powerpc/cpu/mpc83xx/interrupts.c
index faffbaf..446af27 100644
--- a/arch/powerpc/cpu/mpc83xx/interrupts.c
+++ b/arch/powerpc/cpu/mpc83xx/interrupts.c
@@ -90,7 +90,7 @@ void timer_interrupt_cpu (struct pt_regs *regs)
  */
 
 void
-do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
+do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char * const argv[])
 {
 }
 
diff --git a/arch/powerpc/cpu/mpc83xx/speed.c b/arch/powerpc/cpu/mpc83xx/speed.c
index 500eef1..b5076a9 100644
--- a/arch/powerpc/cpu/mpc83xx/speed.c
+++ b/arch/powerpc/cpu/mpc83xx/speed.c
@@ -497,7 +497,7 @@ ulong get_bus_freq(ulong dummy)
 	return gd->csb_clk;
 }
 
-int do_clocks (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_clocks (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	char buf[32];