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/arch/powerpc/cpu/ppc4xx/bedbug_405.c b/arch/powerpc/cpu/ppc4xx/bedbug_405.c
index ef11cb6..e1500cc 100644
--- a/arch/powerpc/cpu/ppc4xx/bedbug_405.c
+++ b/arch/powerpc/cpu/ppc4xx/bedbug_405.c
@@ -17,7 +17,7 @@
extern CPU_DEBUG_CTX bug_ctx;
void bedbug405_init __P ((void));
-void bedbug405_do_break __P ((cmd_tbl_t *, int, int, char *[]));
+void bedbug405_do_break __P ((cmd_tbl_t *, int, int, char * const []));
void bedbug405_break_isr __P ((struct pt_regs *));
int bedbug405_find_empty __P ((void));
int bedbug405_set __P ((int, unsigned long));
@@ -63,7 +63,7 @@
* set routine which will assign a breakpoint number.
* ====================================================================== */
-void bedbug405_do_break (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+void bedbug405_do_break (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
long addr = 0; /* Address to break at */
int which_bp; /* Breakpoint number */