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>
diff --git a/common/hush.c b/common/hush.c
index 9eea90f..8a74d22 100644
--- a/common/hush.c
+++ b/common/hush.c
@@ -94,7 +94,7 @@
#include <hush.h>
#include <command.h> /* find_cmd */
/*cmd_boot.c*/
-extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]); /* do_bootd */
+extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]); /* do_bootd */
#endif
#ifndef __U_BOOT__
#include <ctype.h> /* isalpha, isdigit */
@@ -1024,7 +1024,7 @@
#ifdef CONFIG_BOOT_RETRY_TIME
# ifdef CONFIG_RESET_TO_RETRY
- 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[]);
# else
# error "This currently only works with CONFIG_RESET_TO_RETRY enabled"
# endif
@@ -1681,7 +1681,7 @@
} else {
int rcode;
#if defined(CONFIG_CMD_BOOTD)
- extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+ extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
/* avoid "bootd" recursion */
if (cmdtp->cmd == do_bootd) {
@@ -3351,7 +3351,7 @@
tcsetpgrp(shell_terminal, shell_pgrp);
}
-int hush_main(int argc, char **argv)
+int hush_main(int argc, char * const *argv)
{
int opt;
FILE *input;
@@ -3588,7 +3588,7 @@
}
#ifdef __U_BOOT__
-int do_showvar (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_showvar (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int i, k;
int rcode = 0;