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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>
		
	
			
		
			
				
	
	
		
			77 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			77 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * (C) Copyright 2002
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|  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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|  *
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|  * See file CREDITS for list of people who contributed to this
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|  * project.
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|  *
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|  * This program is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU General Public License as
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|  * published by the Free Software Foundation; either version 2 of
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|  * the License, or (at your option) any later version.
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|  *
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|  * This program is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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|  * GNU General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU General Public License
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|  * along with this program; if not, write to the Free Software
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|  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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|  * MA 02111-1307 USA
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|  */
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| 
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| /*
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|  * Diagnostics support
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|  */
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| #include <common.h>
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| #include <command.h>
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| #include <post.h>
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| 
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| int do_diag (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
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| {
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| 	unsigned int i;
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| 
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| 	if (argc == 1 || strcmp (argv[1], "run") != 0) {
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| 		/* List test info */
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| 		if (argc == 1) {
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| 			puts ("Available hardware tests:\n");
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| 			post_info (NULL);
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| 			puts ("Use 'diag [<test1> [<test2> ...]]'"
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| 					" to get more info.\n");
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| 			puts ("Use 'diag run [<test1> [<test2> ...]]'"
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| 					" to run tests.\n");
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| 		} else {
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| 			for (i = 1; i < argc; i++) {
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| 			    if (post_info (argv[i]) != 0)
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| 				printf ("%s - no such test\n", argv[i]);
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| 			}
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| 		}
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| 	} else {
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| 		/* Run tests */
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| 		if (argc == 2) {
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| 			post_run (NULL, POST_RAM | POST_MANUAL);
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| 		} else {
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| 			for (i = 2; i < argc; i++) {
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| 			    if (post_run (argv[i], POST_RAM | POST_MANUAL) != 0)
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| 				printf ("%s - unable to execute the test\n",
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| 					argv[i]);
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| 			}
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| 		}
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| 	}
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| 
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| 	return 0;
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| }
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| /***************************************************/
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| 
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| U_BOOT_CMD(
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| 	diag,	CONFIG_SYS_MAXARGS,	0,	do_diag,
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| 	"perform board diagnostics",
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| 	     "    - print list of available tests\n"
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| 	"diag [test1 [test2]]\n"
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| 	"         - print information about specified tests\n"
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| 	"diag run - run all available tests\n"
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| 	"diag run [test1 [test2]]\n"
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| 	"         - run specified tests"
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| );
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