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/amirix/ap1000/ap1000.c b/board/amirix/ap1000/ap1000.c
index cadfe0b..c8dd99e 100644
--- a/board/amirix/ap1000/ap1000.c
+++ b/board/amirix/ap1000/ap1000.c
@@ -167,7 +167,7 @@
/*
This function loads FPGA configurations from the SystemACE CompactFlash
*/
-int do_loadace (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_loadace (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned char *p = (unsigned char *) AP1000_SYSACE_REGBASE;
int cfg;
@@ -247,7 +247,7 @@
* -1 if failed
* </pre>
*/
-int do_swconfigbyte (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_swconfigbyte (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
unsigned char *sector_buffer = NULL;
unsigned char input_char;
@@ -311,7 +311,7 @@
#define ONE_SECOND 1000000
-int do_pause (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_pause (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
int pause_time;
unsigned int delay_time;
@@ -345,7 +345,7 @@
return 0;
}
-int do_swreconfig (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_swreconfig (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
printf ("Triggering software reconfigure (software config byte is 0x%02x)...\n",
*((unsigned char *) (SW_BYTE_SECTOR_ADDR + SW_BYTE_SECTOR_OFFSET)));
@@ -365,7 +365,7 @@
#define TEMP_ETHERM_BIT 0x02
#define TEMP_LTHERM_BIT 0x01
-int do_temp_sensor (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_temp_sensor (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
char cmd;
int ret_val = 0;