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	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>
		
	
			
		
			
				
	
	
		
			71 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			71 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| #ifndef __KGDB_H__
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| #define __KGDB_H__
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| 
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| #include <asm/ptrace.h>
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| 
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| #define KGDBERR_BADPARAMS	1
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| #define KGDBERR_NOTHEXDIG	2
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| #define KGDBERR_MEMFAULT	3
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| #define KGDBERR_NOSPACE		4
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| #define KGDBERR_ALIGNFAULT	5
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| 
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| #define KGDBDATA_MAXREGS	8
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| #define KGDBDATA_MAXPRIV	8
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| 
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| #define KGDBEXIT_TYPEMASK	0xff
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| 
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| #define KGDBEXIT_KILL		0
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| #define KGDBEXIT_CONTINUE	1
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| #define KGDBEXIT_SINGLE		2
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| 
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| #define KGDBEXIT_WITHADDR	0x100
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| 
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| typedef
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| 	struct {
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| 		int num;
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| 		unsigned long val;
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| 	}
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| kgdb_reg;
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| 
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| typedef
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| 	struct {
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| 		int sigval;
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| 		int extype;
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| 		unsigned long exaddr;
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| 		int nregs;
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| 		kgdb_reg regs[KGDBDATA_MAXREGS];
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| 		unsigned long private[KGDBDATA_MAXPRIV];
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| 	}
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| kgdb_data;
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| 
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| /* these functions are provided by the generic kgdb support */
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| extern void kgdb_init(void);
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| extern void kgdb_error(int);
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| extern int kgdb_output_string(const char *, unsigned int);
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| extern void breakpoint(void);
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| 
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| /* these functions are provided by the platform specific kgdb support */
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| extern void kgdb_flush_cache_range(void *, void *);
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| extern void kgdb_flush_cache_all(void);
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| extern int kgdb_setjmp(long *);
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| extern void kgdb_longjmp(long *, int);
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| extern void kgdb_enter(struct pt_regs *, kgdb_data *);
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| extern void kgdb_exit(struct pt_regs *, kgdb_data *);
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| extern int kgdb_getregs(struct pt_regs *, char *, int);
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| extern void kgdb_putreg(struct pt_regs *, int, char *, int);
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| extern void kgdb_putregs(struct pt_regs *, char *, int);
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| extern int kgdb_trap(struct pt_regs *);
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| extern void kgdb_breakpoint(int argc, char * const argv[]);
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| 
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| /* these functions are provided by the platform serial driver */
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| extern void kgdb_serial_init(void);
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| extern int getDebugChar(void);
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| extern void putDebugChar(int);
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| extern void putDebugStr(const char *);
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| extern void kgdb_interruptible(int);
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| 
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| /* this is referenced in the trap handler for the platform */
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| extern int (*debugger_exception_handler)(struct pt_regs *);
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| 
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| #endif /* __KGDB_H__ */
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