commit 54841ab50c20d6fa6c9cc3eb826989da3a22d934
author Wolfgang Denk <wd@denx.de> Mon Jun 28 22:00:46 2010 +0200
committer Wolfgang Denk <wd@denx.de> Sun Jul 04 23:55:42 2010 +0200
tree 400f22f0a12ff0ae6c472bed6ac648befc1744a2
parent b218ccb5435e64ac2318bb8b6c9594ef1cc724cd

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>

arch/m68k/cpu/mcf52x2/cpu.c

diff --git a/arch/m68k/cpu/mcf52x2/cpu.c b/arch/m68k/cpu/mcf52x2/cpu.c
index c4c5d50..9fb717c 100644
--- a/arch/m68k/cpu/mcf52x2/cpu.c
+++ b/arch/m68k/cpu/mcf52x2/cpu.c
@@ -38,7 +38,7 @@
 DECLARE_GLOBAL_DATA_PTR;
 
 #ifdef	CONFIG_M5208
-int do_reset(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char * const argv[])
 {
 	volatile rcm_t *rcm = (rcm_t *)(MMAP_RCM);
 
@@ -142,7 +142,7 @@
 	return 0;
 }
 
-int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
 {
 	/* Call the board specific reset actions first. */
 	if(board_reset) {
@@ -177,7 +177,7 @@
 #endif
 
 #ifdef	CONFIG_M5272
-int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
 {
 	volatile wdog_t *wdp = (wdog_t *) (MMAP_WDOG);
 
@@ -257,7 +257,7 @@
 #endif				/* #ifdef CONFIG_M5272 */
 
 #ifdef	CONFIG_M5275
-int do_reset(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char * const argv[])
 {
 	volatile rcm_t *rcm = (rcm_t *)(MMAP_RCM);
 
@@ -337,7 +337,7 @@
 	return 0;
 }
 
-int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
 {
 	MCFRESET_RCR = MCFRESET_RCR_SOFTRST;
 	return 0;
@@ -354,7 +354,7 @@
 	return 0;
 }
 
-int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
 {
 	/* enable watchdog, set timeout to 0 and wait */
 	mbar_writeByte(MCFSIM_SYPCR, 0xc0);
@@ -384,7 +384,7 @@
 	return 0;
 }
 
-int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
 {
 	/* enable watchdog, set timeout to 0 and wait */
 	mbar_writeByte(SIM_SYPCR, 0xc0);