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/cmd_load.c b/common/cmd_load.c
index d6bbb78..52ed1fa 100644
--- a/common/cmd_load.c
+++ b/common/cmd_load.c
@@ -51,7 +51,7 @@
/* -------------------------------------------------------------------- */
#if defined(CONFIG_CMD_LOADS)
-int do_load_serial (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_load_serial (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
long offset = 0;
ulong addr;
@@ -255,7 +255,7 @@
#if defined(CONFIG_CMD_SAVES)
-int do_save_serial (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_save_serial (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong offset = 0;
ulong size = 0;
@@ -433,7 +433,7 @@
char his_pad_char; /* pad chars he needs */
char his_quote; /* quote chars he'll use */
-int do_load_serial_bin (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_load_serial_bin (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong offset = 0;
ulong addr;
@@ -1091,7 +1091,7 @@
/* -------------------------------------------------------------------- */
#if defined(CONFIG_CMD_HWFLOW)
-int do_hwflow (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_hwflow (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
extern int hwflow_onoff(int);
