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, 22 insertions, 22 deletions

diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index 74ff205..bf77fb4 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -78,7 +78,7 @@ static int image_info (unsigned long addr);
 #if defined(CONFIG_CMD_IMLS)
 #include <flash.h>
 extern flash_info_t flash_info[]; /* info for FLASH chips */
-static int do_imls (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+static int do_imls (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
 #endif
 
 #ifdef CONFIG_SILENT_CONSOLE
@@ -90,9 +90,9 @@ static image_header_t *image_get_kernel (ulong img_addr, int verify);
 static int fit_check_kernel (const void *fit, int os_noffset, int verify);
 #endif
 
-static void *boot_get_kernel (cmd_tbl_t *cmdtp, int flag,int argc, char *argv[],
+static void *boot_get_kernel (cmd_tbl_t *cmdtp, int flag,int argc, char * const argv[],
 		bootm_headers_t *images, ulong *os_data, ulong *os_len);
-extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
 
 /*
  *  Continue booting an OS image; caller already has:
@@ -102,7 +102,7 @@ extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
  *  - loaded (first part of) image to header load address,
  *  - disabled interrupts.
  */
-typedef int boot_os_fn (int flag, int argc, char *argv[],
+typedef int boot_os_fn (int flag, int argc, char * const argv[],
 			bootm_headers_t *images); /* pointers to os/initrd/fdt */
 
 #ifdef CONFIG_BOOTM_LINUX
@@ -121,8 +121,8 @@ static boot_os_fn do_bootm_rtems;
 #if defined(CONFIG_CMD_ELF)
 static boot_os_fn do_bootm_vxworks;
 static boot_os_fn do_bootm_qnxelf;
-int do_bootvx (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
-int do_bootelf (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+int do_bootvx (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
+int do_bootelf (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
 #endif
 #if defined(CONFIG_INTEGRITY)
 static boot_os_fn do_bootm_integrity;
@@ -206,7 +206,7 @@ static void bootm_start_lmb(void)
 #endif
 }
 
-static int bootm_start(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int bootm_start(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	void		*os_hdr;
 	int		ret;
@@ -438,10 +438,10 @@ static int bootm_load_os(image_info_t os, ulong *load_end, int boot_progress)
 	return 0;
 }
 
-static int bootm_start_standalone(ulong iflag, int argc, char *argv[])
+static int bootm_start_standalone(ulong iflag, int argc, char * const argv[])
 {
 	char  *s;
-	int   (*appl)(int, char *[]);
+	int   (*appl)(int, char * const []);
 
 	/* Don't start if "autostart" is set to "no" */
 	if (((s = getenv("autostart")) != NULL) && (strcmp(s, "no") == 0)) {
@@ -450,7 +450,7 @@ static int bootm_start_standalone(ulong iflag, int argc, char *argv[])
 		setenv("filesize", buf);
 		return 0;
 	}
-	appl = (int (*)(int, char *[]))ntohl(images.ep);
+	appl = (int (*)(int, char * const []))ntohl(images.ep);
 	(*appl)(argc-1, &argv[1]);
 
 	return 0;
@@ -473,7 +473,7 @@ static cmd_tbl_t cmd_bootm_sub[] = {
 	U_BOOT_CMD_MKENT(go, 0, 1, (void *)BOOTM_STATE_OS_GO, "", ""),
 };
 
-int do_bootm_subcommand (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bootm_subcommand (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	int ret = 0;
 	int state;
@@ -576,7 +576,7 @@ int do_bootm_subcommand (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 /* bootm - boot application image from image in memory */
 /*******************************************************************/
 
-int do_bootm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bootm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong		iflag;
 	ulong		load_end = 0;
@@ -811,7 +811,7 @@ static int fit_check_kernel (const void *fit, int os_noffset, int verify)
  *     pointer to image header if valid image was found, plus kernel start
  *     address and length, otherwise NULL
  */
-static void *boot_get_kernel (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[],
+static void *boot_get_kernel (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		bootm_headers_t *images, ulong *os_data, ulong *os_len)
 {
 	image_header_t	*hdr;
@@ -1012,7 +1012,7 @@ U_BOOT_CMD(
 /* bootd - boot default image */
 /*******************************************************************/
 #if defined(CONFIG_CMD_BOOTD)
-int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	int rcode = 0;
 
@@ -1047,7 +1047,7 @@ U_BOOT_CMD(
 /* iminfo - print header info for a requested image */
 /*******************************************************************/
 #if defined(CONFIG_CMD_IMI)
-int do_iminfo (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_iminfo (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	int	arg;
 	ulong	addr;
@@ -1134,7 +1134,7 @@ U_BOOT_CMD(
 /* imls - list all images found in flash */
 /*******************************************************************/
 #if defined(CONFIG_CMD_IMLS)
-int do_imls (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_imls (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	flash_info_t *info;
 	int i, j;
@@ -1237,7 +1237,7 @@ static void fixup_silent_linux ()
 /*******************************************************************/
 
 #ifdef CONFIG_BOOTM_NETBSD
-static int do_bootm_netbsd (int flag, int argc, char *argv[],
+static int do_bootm_netbsd (int flag, int argc, char * const argv[],
 			    bootm_headers_t *images)
 {
 	void (*loader)(bd_t *, image_header_t *, char *, char *);
@@ -1325,7 +1325,7 @@ static int do_bootm_netbsd (int flag, int argc, char *argv[],
 #endif /* CONFIG_BOOTM_NETBSD*/
 
 #ifdef CONFIG_LYNXKDI
-static int do_bootm_lynxkdi (int flag, int argc, char *argv[],
+static int do_bootm_lynxkdi (int flag, int argc, char * const argv[],
 			     bootm_headers_t *images)
 {
 	image_header_t *hdr = &images->legacy_hdr_os_copy;
@@ -1347,7 +1347,7 @@ static int do_bootm_lynxkdi (int flag, int argc, char *argv[],
 #endif /* CONFIG_LYNXKDI */
 
 #ifdef CONFIG_BOOTM_RTEMS
-static int do_bootm_rtems (int flag, int argc, char *argv[],
+static int do_bootm_rtems (int flag, int argc, char * const argv[],
 			   bootm_headers_t *images)
 {
 	void (*entry_point)(bd_t *);
@@ -1380,7 +1380,7 @@ static int do_bootm_rtems (int flag, int argc, char *argv[],
 #endif /* CONFIG_BOOTM_RTEMS */
 
 #if defined(CONFIG_CMD_ELF)
-static int do_bootm_vxworks (int flag, int argc, char *argv[],
+static int do_bootm_vxworks (int flag, int argc, char * const argv[],
 			     bootm_headers_t *images)
 {
 	char str[80];
@@ -1402,7 +1402,7 @@ static int do_bootm_vxworks (int flag, int argc, char *argv[],
 	return 1;
 }
 
-static int do_bootm_qnxelf(int flag, int argc, char *argv[],
+static int do_bootm_qnxelf(int flag, int argc, char * const argv[],
 			    bootm_headers_t *images)
 {
 	char *local_args[2];
@@ -1428,7 +1428,7 @@ static int do_bootm_qnxelf(int flag, int argc, char *argv[],
 #endif
 
 #ifdef CONFIG_INTEGRITY
-static int do_bootm_integrity (int flag, int argc, char *argv[],
+static int do_bootm_integrity (int flag, int argc, char * const argv[],
 			   bootm_headers_t *images)
 {
 	void (*entry_point)(void);