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, 10 insertions, 10 deletions

diff --git a/common/cmd_onenand.c b/common/cmd_onenand.c
index 2646ae9..a3e46a3 100644
--- a/common/cmd_onenand.c
+++ b/common/cmd_onenand.c
@@ -32,7 +32,7 @@ static inline int str2long(char *p, ulong *num)
 	return (*p != '\0' && *endptr == '\0') ? 1 : 0;
 }
 
-static int arg_off_size(int argc, char *argv[], ulong *off, size_t *size)
+static int arg_off_size(int argc, char * const argv[], ulong *off, size_t *size)
 {
 	if (argc >= 1) {
 		if (!(str2long(argv[0], off))) {
@@ -330,13 +330,13 @@ static int onenand_dump(struct mtd_info *mtd, ulong off, int only_oob)
 	return 0;
 }
 
-static int do_onenand_info(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_info(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	printf("%s\n", mtd->name);
 	return 0;
 }
 
-static int do_onenand_bad(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_bad(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong ofs;
 
@@ -351,7 +351,7 @@ static int do_onenand_bad(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 	return 0;
 }
 
-static int do_onenand_read(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_read(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	char *s;
 	int oob = 0;
@@ -383,7 +383,7 @@ static int do_onenand_read(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 	return ret == 0 ? 0 : 1;
 }
 
-static int do_onenand_write(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_write(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong addr, ofs;
 	size_t len;
@@ -409,7 +409,7 @@ static int do_onenand_write(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 	return ret == 0 ? 0 : 1;
 }
 
-static int do_onenand_erase(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_erase(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong ofs;
 	int ret = 0;
@@ -445,7 +445,7 @@ static int do_onenand_erase(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 	return ret == 0 ? 0 : 1;
 }
 
-static int do_onenand_test(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_test(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong ofs;
 	int ret = 0;
@@ -470,7 +470,7 @@ static int do_onenand_test(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 	return ret == 0 ? 0 : 1;
 }
 
-static int do_onenand_dump(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_dump(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong ofs;
 	int ret = 0;
@@ -493,7 +493,7 @@ static int do_onenand_dump(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 	return ret == 0 ? 1 : 0;
 }
 
-static int do_onenand_markbad(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand_markbad(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	int ret = 0;
 	ulong addr;
@@ -537,7 +537,7 @@ static cmd_tbl_t cmd_onenand_sub[] = {
 	U_BOOT_CMD_MKENT(markbad, CONFIG_SYS_MAXARGS, 0, do_onenand_markbad, "", ""),
 };
 
-static int do_onenand(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_onenand(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 {
 	cmd_tbl_t *c;