commit 6262d021d2a0f6fe9bef2bc5ebeb761e5a9469fc
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 89f5df994c019b7455accb4e57fb4e2815a70725

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>

common/cmd_yaffs2.c

diff --git a/common/cmd_yaffs2.c b/common/cmd_yaffs2.c
index d448d04..7c01ea2 100644
--- a/common/cmd_yaffs2.c
+++ b/common/cmd_yaffs2.c
@@ -24,7 +24,7 @@
 extern int yaffs_DumpDevStruct(const char *path);
 
 
-int do_ymount (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_ymount (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *mtpoint = argv[1];
     cmd_yaffs_mount(mtpoint);
@@ -32,7 +32,7 @@
     return(0);
 }
 
-int do_yumount (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_yumount (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *mtpoint = argv[1];
     cmd_yaffs_umount(mtpoint);
@@ -40,7 +40,7 @@
     return(0);
 }
 
-int do_yls (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_yls (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *dirname = argv[argc-1];
 
@@ -49,7 +49,7 @@
     return(0);
 }
 
-int do_yrd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_yrd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *filename = argv[1];
     printf ("Reading file %s ", filename);
@@ -60,7 +60,7 @@
     return(0);
 }
 
-int do_ywr (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_ywr (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *filename = argv[1];
     ulong value = simple_strtoul(argv[2], NULL, 16);
@@ -74,7 +74,7 @@
     return(0);
 }
 
-int do_yrdm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_yrdm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *filename = argv[1];
     ulong addr = simple_strtoul(argv[2], NULL, 16);
@@ -84,7 +84,7 @@
     return(0);
 }
 
-int do_ywrm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_ywrm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *filename = argv[1];
     ulong addr = simple_strtoul(argv[2], NULL, 16);
@@ -95,7 +95,7 @@
     return(0);
 }
 
-int do_ymkdir (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_ymkdir (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *dirname = argv[1];
 
@@ -104,7 +104,7 @@
     return(0);
 }
 
-int do_yrmdir (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_yrmdir (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *dirname = argv[1];
 
@@ -113,7 +113,7 @@
     return(0);
 }
 
-int do_yrm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_yrm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *path = argv[1];
 
@@ -122,7 +122,7 @@
     return(0);
 }
 
-int do_ymv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_ymv (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *oldPath = argv[1];
     char *newPath = argv[2];
@@ -132,7 +132,7 @@
     return(0);
 }
 
-int do_ydump (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_ydump (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
     char *dirname = argv[1];
     if (yaffs_DumpDevStruct(dirname) != 0)