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/zeus/zeus.c b/board/zeus/zeus.c
index 01273a1..e295151 100644
--- a/board/zeus/zeus.c
+++ b/board/zeus/zeus.c
@@ -44,7 +44,7 @@
ulong flash_get_size(ulong base, int banknum);
void env_crc_update(void);
-int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
static u32 start_time;
@@ -278,7 +278,7 @@
return 0;
}
-int do_set_default(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_set_default(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
char *buf;
char *buf_save;
@@ -336,7 +336,7 @@
return !(in_be32((void *)GPIO0_IR) & GPIO_VAL(CONFIG_SYS_GPIO_SW_RESET));
}
-int do_chkreset(cmd_tbl_t* cmdtp, int flag, int argc, char* argv[])
+int do_chkreset(cmd_tbl_t* cmdtp, int flag, int argc, char * const argv[])
{
int delta;
int count = 0;