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>

1 files changed, 8 insertions, 8 deletions

diff --git a/common/cmd_bdinfo.c b/common/cmd_bdinfo.c
index 710abdf..fbe73f1 100644
--- a/common/cmd_bdinfo.c
+++ b/common/cmd_bdinfo.c
@@ -42,7 +42,7 @@ static void print_lnum(const char *, u64);
 #if defined(CONFIG_PPC)
 static void print_str(const char *, const char *);
 
-int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;
 	char buf[32];
@@ -122,7 +122,7 @@ int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 #elif defined(CONFIG_NIOS2)
 
-int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;
 
@@ -149,7 +149,7 @@ int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 #elif defined(CONFIG_MICROBLAZE)
 
-int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;
 	print_num ("mem start      ",	(ulong)bd->bi_memstart);
@@ -171,7 +171,7 @@ int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 #elif defined(CONFIG_SPARC)
 
-int do_bdinfo(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;
 
@@ -206,7 +206,7 @@ int do_bdinfo(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 
 static void print_str(const char *, const char *);
 
-int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;
 	char buf[32];
@@ -256,7 +256,7 @@ int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 static void print_str(const char *, const char *);
 
-int do_bdinfo(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;
 	char buf[32];
@@ -284,7 +284,7 @@ int do_bdinfo(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 #elif defined(CONFIG_MIPS)
 
-int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;
 
@@ -324,7 +324,7 @@ int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 #elif defined(CONFIG_ARM)
 
-int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	int i;
 	bd_t *bd = gd->bd;