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/board/trab/cmd_trab.c b/board/trab/cmd_trab.c
index 472d7d8..6d23470 100644
--- a/board/trab/cmd_trab.c
+++ b/board/trab/cmd_trab.c
@@ -109,16 +109,16 @@
extern void tsc2000_spi_init(void);
/* function declarations */
-int do_dip (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
-int do_vcc5v (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
-int do_burn_in (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
-int do_contact_temp (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
-int do_burn_in_status (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+int do_dip (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
+int do_vcc5v (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
+int do_burn_in (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
+int do_contact_temp (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
+int do_burn_in_status (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
int i2c_write_multiple (uchar chip, uint addr, int alen,
uchar *buffer, int len);
int i2c_read_multiple (uchar chip, uint addr, int alen,
uchar *buffer, int len);
-int do_temp_log (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+int do_temp_log (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
/* helper functions */
static void adc_init (void);
@@ -162,7 +162,7 @@
test_function_t test_function[BIF_MAX];
-int do_burn_in (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_burn_in (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int i;
int cycle_status;
@@ -266,7 +266,7 @@
);
-int do_dip (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_dip (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int i, dip;
@@ -299,7 +299,7 @@
);
-int do_vcc5v (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_vcc5v (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int vcc5v;
@@ -327,7 +327,7 @@
);
-int do_contact_temp (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_contact_temp (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int contact_temp;
@@ -352,7 +352,7 @@
);
-int do_burn_in_status (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_burn_in_status (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
if (argc > 1) {
cmd_usage(cmdtp);
@@ -842,7 +842,7 @@
return (0);
}
-int do_temp_log (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_temp_log (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int contact_temp;
int delay = 0;