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_i2c.c b/common/cmd_i2c.c
index 8b9c2c9..fb9d3b0 100644
--- a/common/cmd_i2c.c
+++ b/common/cmd_i2c.c
@@ -178,7 +178,7 @@
* i2c read {i2c_chip} {devaddr}{.0, .1, .2} {len} {memaddr}
*/
-static int do_i2c_read ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_read ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
u_char chip;
uint devaddr, alen, length;
@@ -226,7 +226,7 @@
* Syntax:
* i2c md {i2c_chip} {addr}{.0, .1, .2} {len}
*/
-static int do_i2c_md ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_md ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
u_char chip;
uint addr, alen, length;
@@ -324,7 +324,7 @@
* Syntax:
* i2c mw {i2c_chip} {addr}{.0, .1, .2} {data} [{count}]
*/
-static int do_i2c_mw ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_mw ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
uchar chip;
ulong addr;
@@ -388,7 +388,7 @@
* Syntax:
* i2c crc32 {i2c_chip} {addr}{.0, .1, .2} {count}
*/
-static int do_i2c_crc (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_crc (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
uchar chip;
ulong addr;
@@ -452,7 +452,7 @@
*/
static int
-mod_i2c_mem(cmd_tbl_t *cmdtp, int incrflag, int flag, int argc, char *argv[])
+mod_i2c_mem(cmd_tbl_t *cmdtp, int incrflag, int flag, int argc, char * const argv[])
{
uchar chip;
ulong addr;
@@ -575,7 +575,7 @@
* Syntax:
* i2c probe {addr}{.0, .1, .2}
*/
-static int do_i2c_probe (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_probe (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int j;
#if defined(CONFIG_SYS_I2C_NOPROBES)
@@ -619,7 +619,7 @@
* {length} - Number of bytes to read
* {delay} - A DECIMAL number and defaults to 1000 uSec
*/
-static int do_i2c_loop(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_loop(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
u_char chip;
ulong alen;
@@ -731,7 +731,7 @@
* Syntax:
* i2c sdram {i2c_chip}
*/
-static int do_sdram (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_sdram (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
enum { unknown, EDO, SDRAM, DDR2 } type;
@@ -1208,7 +1208,7 @@
#endif
#if defined(CONFIG_I2C_MUX)
-static int do_i2c_add_bus(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_add_bus(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
int ret=0;
@@ -1239,7 +1239,7 @@
#endif /* CONFIG_I2C_MUX */
#if defined(CONFIG_I2C_MULTI_BUS)
-static int do_i2c_bus_num(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_bus_num(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
int bus_idx, ret=0;
@@ -1257,7 +1257,7 @@
}
#endif /* CONFIG_I2C_MULTI_BUS */
-static int do_i2c_bus_speed(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_bus_speed(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
int speed, ret=0;
@@ -1274,17 +1274,17 @@
return ret;
}
-static int do_i2c_mm(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_mm(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
return mod_i2c_mem (cmdtp, 1, flag, argc, argv);
}
-static int do_i2c_nm(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_nm(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
return mod_i2c_mem (cmdtp, 0, flag, argc, argv);
}
-static int do_i2c_reset(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_i2c_reset(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
return 0;
@@ -1312,7 +1312,7 @@
U_BOOT_CMD_MKENT(speed, 1, 1, do_i2c_bus_speed, "", ""),
};
-static int do_i2c(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int do_i2c(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
cmd_tbl_t *c;