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>

3 files changed, 4 insertions, 4 deletions

diff --git a/arch/powerpc/cpu/mpc8260/bedbug_603e.c b/arch/powerpc/cpu/mpc8260/bedbug_603e.c
index c969ff6..2488612 100644
--- a/arch/powerpc/cpu/mpc8260/bedbug_603e.c
+++ b/arch/powerpc/cpu/mpc8260/bedbug_603e.c
@@ -18,7 +18,7 @@
 extern CPU_DEBUG_CTX bug_ctx;
 
 void bedbug603e_init __P((void));
-void bedbug603e_do_break __P((cmd_tbl_t*,int,int,char*[]));
+void bedbug603e_do_break __P((cmd_tbl_t*,int,int,char*const[]));
 void bedbug603e_break_isr __P((struct pt_regs*));
 int  bedbug603e_find_empty __P((void));
 int  bedbug603e_set __P((int,unsigned long));
@@ -64,7 +64,7 @@ void bedbug603e_init( void )
  * ====================================================================== */
 
 void bedbug603e_do_break (cmd_tbl_t *cmdtp, int flag, int argc,
-			 char *argv[])
+			 char * const argv[])
 {
   long		addr;           /* Address to break at  */
   int		which_bp;       /* Breakpoint number    */
diff --git a/arch/powerpc/cpu/mpc8260/cpu.c b/arch/powerpc/cpu/mpc8260/cpu.c
index aedbf29..220c1e2 100644
--- a/arch/powerpc/cpu/mpc8260/cpu.c
+++ b/arch/powerpc/cpu/mpc8260/cpu.c
@@ -238,7 +238,7 @@ void upmconfig (uint upm, uint * table, uint size)
 
 #if !defined(CONFIG_HAVE_OWN_RESET)
 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, addr;
 
diff --git a/arch/powerpc/cpu/mpc8260/interrupts.c b/arch/powerpc/cpu/mpc8260/interrupts.c
index 2606c60..79178cc 100644
--- a/arch/powerpc/cpu/mpc8260/interrupts.c
+++ b/arch/powerpc/cpu/mpc8260/interrupts.c
@@ -256,7 +256,7 @@ 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[])
 {
 	int irq, re_enable;