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authorWolfgang Denk <wd@denx.de>2010-06-28 22:00:46 +0200
committerWolfgang Denk <wd@denx.de>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /board/bc3450/cmd_bc3450.c
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
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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>
Diffstat (limited to 'board/bc3450/cmd_bc3450.c')
-rw-r--r--board/bc3450/cmd_bc3450.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/board/bc3450/cmd_bc3450.c b/board/bc3450/cmd_bc3450.c
index 271ffb1..a9e4902 100644
--- a/board/bc3450/cmd_bc3450.c
+++ b/board/bc3450/cmd_bc3450.c
@@ -173,7 +173,7 @@ int sm501_gpio_init (void)
* read and prints the dip switch
* and/or external config inputs (4bits) 0...0x0F
*/
-int cmd_dip (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int cmd_dip (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
vu_long rc = 0;
@@ -205,7 +205,7 @@ U_BOOT_CMD (dip, 1, 1, cmd_dip,
* buz - turns Buzzer on/off
*/
#ifdef CONFIG_BC3450_BUZZER
-static int cmd_buz (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int cmd_buz (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
if (argc != 2) {
printf ("Usage:\nspecify one argument: \"on\" or \"off\"\n");
@@ -236,7 +236,7 @@ U_BOOT_CMD (buz, 2, 1, cmd_buz,
/*
* fp - front panel commands
*/
-static int cmd_fp (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int cmd_fp (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
sm501_gpio_init ();
@@ -491,7 +491,7 @@ static void ds1620_write_state (struct therm *therm)
ds1620_out (THERM_START_CONVERT, 0, 0);
}
-static int cmd_temp (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int cmd_temp (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
int i;
struct therm therm;
@@ -682,7 +682,7 @@ int can_init (void)
* return 1 on CAN failure
* return 0 if no failure
*/
-int do_can (char *argv[])
+int do_can (char * const argv[])
{
int i;
struct mpc5xxx_mscan *can1 =
@@ -777,7 +777,7 @@ int do_can (char *argv[])
/*
* test - BC3450 HW test routines
*/
-int cmd_test (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int cmd_test (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
#ifdef CONFIG_BC3450_CAN
int rcode;