busybox/miscutils/rx.c

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2003-12-20 13:00:35 +05:30
/*-------------------------------------------------------------------------
* Filename: xmodem.c
* Version: $Id: rx.c,v 1.1 2003/12/20 07:30:35 bug1 Exp $
* Copyright: Copyright (C) 2001, Hewlett-Packard Company
* Author: Christopher Hoover <ch@hpl.hp.com>
* Description: xmodem functionality for uploading of kernels
* and the like
* Created at: Thu Dec 20 01:58:08 PST 2001
*-----------------------------------------------------------------------*/
/*
* xmodem.c: xmodem functionality for uploading of kernels and
* the like
*
* Copyright (C) 2001 Hewlett-Packard Laboratories
*
* 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
*
*
* This was originally written for blob and then adapted for busybox.
*
*/
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <termios.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include "busybox.h"
#define SOH 0x01
#define STX 0x02
#define EOT 0x04
#define ACK 0x06
#define NAK 0x15
#define CAN 0x18
#define BS 0x08
/*
Cf:
http://www.textfiles.com/apple/xmodem
http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt
http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt
http://www.phys.washington.edu/~belonis/xmodem/modmprot.col
*/
#define TIMEOUT 1
#define TIMEOUT_LONG 10
#define MAXERRORS 10
static inline void write_byte(int fd, char cc) {
write(fd, &cc, 1);
}
static inline void write_flush(int fd) {
tcdrain(fd);
}
static inline void read_flush(int fd) {
tcflush(fd, TCIFLUSH);
}
static int read_byte(int fd, unsigned int timeout) {
char buf[1];
int n;
alarm(timeout);
n = read(fd, &buf, 1);
alarm(0);
if (n == 1)
return buf[0] & 0xff;
else
return -1;
}
static int receive(char *error_buf, size_t error_buf_size,
int ttyfd, int filefd)
{
char blockBuf[1024];
unsigned int errors = 0;
unsigned int wantBlockNo = 1;
unsigned int length = 0;
int docrc = 1;
char nak = 'C';
unsigned int timeout = TIMEOUT_LONG;
#define note_error(fmt,args...) \
snprintf(error_buf, error_buf_size, fmt,##args)
read_flush(ttyfd);
/* Ask for CRC; if we get errors, we will go with checksum */
write_byte(ttyfd, nak);
write_flush(ttyfd);
for (;;) {
int blockBegin;
int blockNo, blockNoOnesCompl;
int blockLength;
int cksum = 0;
int crcHi = 0;
int crcLo = 0;
blockBegin = read_byte(ttyfd, timeout);
if (blockBegin < 0)
goto timeout;
timeout = TIMEOUT;
nak = NAK;
switch (blockBegin) {
case SOH:
case STX:
break;
case EOT:
write_byte(ttyfd, ACK);
write_flush(ttyfd);
goto done;
default:
goto error;
}
/* block no */
blockNo = read_byte(ttyfd, TIMEOUT);
if (blockNo < 0)
goto timeout;
/* block no one's compliment */
blockNoOnesCompl = read_byte(ttyfd, TIMEOUT);
if (blockNoOnesCompl < 0)
goto timeout;
if (blockNo != (255 - blockNoOnesCompl)) {
note_error("bad block ones compl");
goto error;
}
blockLength = (blockBegin == SOH) ? 128 : 1024;
{
int i;
for (i = 0; i < blockLength; i++) {
int cc = read_byte(ttyfd, TIMEOUT);
if (cc < 0)
goto timeout;
blockBuf[i] = cc;
}
}
if (docrc) {
crcHi = read_byte(ttyfd, TIMEOUT);
if (crcHi < 0)
goto timeout;
crcLo = read_byte(ttyfd, TIMEOUT);
if (crcLo < 0)
goto timeout;
} else {
cksum = read_byte(ttyfd, TIMEOUT);
if (cksum < 0)
goto timeout;
}
if (blockNo == ((wantBlockNo - 1) & 0xff)) {
/* a repeat of the last block is ok, just ignore it. */
/* this also ignores the initial block 0 which is */
/* meta data. */
goto next;
} else if (blockNo != (wantBlockNo & 0xff)) {
note_error("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo);
goto error;
}
if (docrc) {
int crc = 0;
int i, j;
int expectedCrcHi;
int expectedCrcLo;
for (i = 0; i < blockLength; i++) {
crc = crc ^ (int) blockBuf[i] << 8;
for (j = 0; j < 8; j++)
if (crc & 0x8000)
crc = crc << 1 ^ 0x1021;
else
crc = crc << 1;
}
expectedCrcHi = (crc >> 8) & 0xff;
expectedCrcLo = crc & 0xff;
if ((crcHi != expectedCrcHi) ||
(crcLo != expectedCrcLo)) {
note_error("crc error, expected 0x%02x 0x%02x, got 0x%02x 0x%02x", expectedCrcHi, expectedCrcLo, crcHi, crcLo);
goto error;
}
} else {
unsigned char expectedCksum = 0;
int i;
for (i = 0; i < blockLength; i++)
expectedCksum += blockBuf[i];
if (cksum != expectedCksum) {
note_error("checksum error, expected 0x%02x, got 0x%02x", expectedCksum, cksum);
goto error;
}
}
wantBlockNo++;
length += blockLength;
if (bb_full_write(filefd, blockBuf, blockLength) < 0) {
note_error("write to file failed: %m");
goto fatal;
}
next:
errors = 0;
write_byte(ttyfd, ACK);
write_flush(ttyfd);
continue;
error:
timeout:
errors++;
if (errors == MAXERRORS) {
/* Abort */
int i;
// if using crc, try again w/o crc
if (nak == 'C') {
nak = NAK;
errors = 0;
docrc = 0;
goto timeout;
}
note_error("too many errors; giving up");
fatal:
for (i = 0; i < 5; i ++)
write_byte(ttyfd, CAN);
for (i = 0; i < 5; i ++)
write_byte(ttyfd, BS);
write_flush(ttyfd);
return -1;
}
read_flush(ttyfd);
write_byte(ttyfd, nak);
write_flush(ttyfd);
}
done:
return length;
#undef note_error
}
static void sigalrm_handler(int signum)
{
}
int rx_main(int argc, char **argv)
{
char *fn;
int ttyfd, filefd;
struct termios tty, orig_tty;
struct sigaction act;
int n;
char error_buf[256];
if (argc != 2)
bb_show_usage();
fn = argv[1];
ttyfd = open("/dev/tty", O_RDWR);
if (ttyfd < 0)
bb_error_msg_and_die("%s: open on /dev/tty failed: %m\n", argv[0]);
filefd = open(fn, O_RDWR|O_CREAT|O_TRUNC, 0666);
if (filefd < 0)
bb_error_msg_and_die("%s: open on %s failed: %m\n", argv[0], fn);
if (tcgetattr(ttyfd, &tty) < 0)
bb_error_msg_and_die("%s: tcgetattr failed: %m\n", argv[0]);
orig_tty = tty;
cfmakeraw(&tty);
tcsetattr(ttyfd, TCSAFLUSH, &tty);
memset(&act, 0, sizeof(act));
act.sa_handler = sigalrm_handler;
sigaction(SIGALRM, &act, 0);
n = receive(error_buf, sizeof(error_buf), ttyfd, filefd);
close(filefd);
tcsetattr(ttyfd, TCSAFLUSH, &orig_tty);
if (n < 0)
bb_error_msg_and_die("\n%s: receive failed:\n %s\n",
argv[0], error_buf);
bb_fflush_stdout_and_exit(EXIT_SUCCESS);
}
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/