u-boot/include/bedbug/type.h
Wolfgang Denk 54841ab50c 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>
2010-07-04 23:55:42 +02:00

27 lines
587 B
C

#ifndef _TYPE_BEDBUG_H
#define _TYPE_BEDBUG_H
/* Supporting routines */
int bedbug_puts (const char *);
void bedbug_init (void);
void bedbug860_init (void);
void do_bedbug_breakpoint (struct pt_regs *);
void bedbug_main_loop (unsigned long, struct pt_regs *);
typedef struct {
int hw_debug_enabled;
int stopped;
int current_bp;
struct pt_regs *regs;
void (*do_break) (cmd_tbl_t *, int, int, char * const []);
void (*break_isr) (struct pt_regs *);
int (*find_empty) (void);
int (*set) (int, unsigned long);
int (*clear) (int);
} CPU_DEBUG_CTX;
#endif /* _TYPE_BEDBUG_H */