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/board/esd/common/auto_update.c b/board/esd/common/auto_update.c
index c4a49e2..4dfea71 100644
--- a/board/esd/common/auto_update.c
+++ b/board/esd/common/auto_update.c
@@ -492,7 +492,7 @@ int do_auto_update(void)
 	return 0;
 }
 
-int auto_update(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int auto_update(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	do_auto_update();
 
diff --git a/board/esd/common/cmd_loadpci.c b/board/esd/common/cmd_loadpci.c
index eecae0a..87da27d 100644
--- a/board/esd/common/cmd_loadpci.c
+++ b/board/esd/common/cmd_loadpci.c
@@ -37,7 +37,7 @@ extern int do_source (cmd_tbl_t *, int, int, char *[]);
 /*
  * Command loadpci: wait for signal from host and boot image.
  */
-int do_loadpci(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_loadpci(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	u32 *ptr = 0;
 	int count = 0;
diff --git a/board/esd/common/lcd.c b/board/esd/common/lcd.c
index 5c50b4c..9109b64 100644
--- a/board/esd/common/lcd.c
+++ b/board/esd/common/lcd.c
@@ -339,7 +339,7 @@ int lcd_init(uchar *lcd_reg, uchar *lcd_mem, S1D_REGS *regs, int reg_count,
 	return lcd_bmp(logo_bmp);
 }
 
-int do_esdbmp(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_esdbmp(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong addr;
 #ifdef CONFIG_VIDEO_SM501
diff --git a/board/esd/common/xilinx_jtag/micro.c b/board/esd/common/xilinx_jtag/micro.c
index 414e821..9823e5e 100644
--- a/board/esd/common/xilinx_jtag/micro.c
+++ b/board/esd/common/xilinx_jtag/micro.c
@@ -1828,7 +1828,7 @@ int xsvfExecute(void)
  *               ppzArgv  - array of ptrs to strings (command-line arguments).
  * Returns:      int      - Legacy return value:  1 = success; 0 = error.
  *****************************************************************************/
-int do_cpld(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_cpld(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	int     iErrorCode;
 	char*   pzXsvfFileName;