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_nvedit.c b/common/cmd_nvedit.c
index d2ef217..13325bc 100644
--- a/common/cmd_nvedit.c
+++ b/common/cmd_nvedit.c
@@ -139,7 +139,7 @@
return i;
}
-int do_printenv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_printenv (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int i;
int rcode = 0;
@@ -173,7 +173,7 @@
* This function will ONLY work with a in-RAM copy of the environment
*/
-int _do_setenv (int flag, int argc, char *argv[])
+int _do_setenv (int flag, int argc, char * const argv[])
{
int i, len, oldval;
int console = -1;
@@ -390,7 +390,7 @@
int setenv (char *varname, char *varvalue)
{
- char *argv[4] = { "setenv", varname, varvalue, NULL };
+ char * const argv[4] = { "setenv", varname, varvalue, NULL };
if ((varvalue == NULL) || (varvalue[0] == '\0'))
return _do_setenv (0, 2, argv);
else
@@ -400,12 +400,12 @@
#ifdef CONFIG_HAS_UID
void forceenv (char *varname, char *varvalue)
{
- char *argv[4] = { "forceenv", varname, varvalue, NULL };
+ char * const argv[4] = { "forceenv", varname, varvalue, NULL };
_do_setenv (0xdeaf4add, 3, argv);
}
#endif
-int do_setenv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_setenv (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
if (argc < 2) {
cmd_usage(cmdtp);
@@ -420,7 +420,7 @@
*/
#if defined(CONFIG_CMD_ASKENV)
-int do_askenv ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_askenv ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
extern char console_buffer[CONFIG_SYS_CBSIZE];
char message[CONFIG_SYS_CBSIZE];
@@ -497,7 +497,7 @@
* Interactively edit an environment variable
*/
#if defined(CONFIG_CMD_EDITENV)
-int do_editenv(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_editenv(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
char buffer[CONFIG_SYS_CBSIZE];
char *init_val;
@@ -576,7 +576,7 @@
#if defined(CONFIG_CMD_SAVEENV) && !defined(CONFIG_ENV_IS_NOWHERE)
-int do_saveenv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_saveenv (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
extern char * env_name_spec;
@@ -660,7 +660,7 @@
#endif
#if defined(CONFIG_CMD_RUN)
-int do_run (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+int do_run (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
U_BOOT_CMD(
run, CONFIG_SYS_MAXARGS, 1, do_run,
"run commands in an environment variable",