Forked from
Reform / reform-boundary-uboot
38661 commits behind the upstream repository.
-
Wolfgang Denk authored
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>
Wolfgang Denk authoredThe 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:
cmd_terminal.c 2.11 KiB
/*
* (C) Copyright 2007 OpenMoko, Inc.
* Written by Harald Welte <laforge@openmoko.org>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* Boot support
*/
#include <common.h>
#include <command.h>
#include <stdio_dev.h>
#include <serial.h>
int do_terminal(cmd_tbl_t * cmd, int flag, int argc, char * const argv[])
{
int last_tilde = 0;
struct stdio_dev *dev = NULL;
if (argc < 1)
return -1;
/* Scan for selected output/input device */
dev = stdio_get_by_name(argv[1]);
if (!dev)
return -1;
serial_reinit_all();
printf("Entering terminal mode for port %s\n", dev->name);
puts("Use '~.' to leave the terminal and get back to u-boot\n");
while (1) {
int c;
/* read from console and display on serial port */
if (stdio_devices[0]->tstc()) {
c = stdio_devices[0]->getc();
if (last_tilde == 1) {
if (c == '.') {
putc(c);
putc('\n');
break;
} else {
last_tilde = 0;
/* write the delayed tilde */
dev->putc('~');
/* fall-through to print current
* character */
}
}
if (c == '~') {
last_tilde = 1;
puts("[u-boot]"); putc(c);
}
dev->putc(c);
}
/* read from serial port and display on console */
if (dev->tstc()) {
c = dev->getc();
putc(c);
}
}
return 0;
}
/***************************************************/
U_BOOT_CMD(
terminal, 3, 1, do_terminal,
"start terminal emulator",
""
);