332 lines
6.5 KiB
C
332 lines
6.5 KiB
C
/*-------------------------------------------------------------------------
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* Filename: xmodem.c
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* Version: $Id: rx.c,v 1.2 2004/03/15 08:28:46 andersen Exp $
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* Copyright: Copyright (C) 2001, Hewlett-Packard Company
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* Author: Christopher Hoover <ch@hpl.hp.com>
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* Description: xmodem functionality for uploading of kernels
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* and the like
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* Created at: Thu Dec 20 01:58:08 PST 2001
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*-----------------------------------------------------------------------*/
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/*
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* xmodem.c: xmodem functionality for uploading of kernels and
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* the like
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*
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* Copyright (C) 2001 Hewlett-Packard Laboratories
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*
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* This was originally written for blob and then adapted for busybox.
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*
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*/
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#include <stdlib.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <errno.h>
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#include <termios.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <string.h>
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#include "busybox.h"
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#define SOH 0x01
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#define STX 0x02
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#define EOT 0x04
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#define ACK 0x06
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#define NAK 0x15
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#define CAN 0x18
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#define BS 0x08
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/*
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Cf:
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http://www.textfiles.com/apple/xmodem
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http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt
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http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt
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http://www.phys.washington.edu/~belonis/xmodem/modmprot.col
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*/
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#define TIMEOUT 1
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#define TIMEOUT_LONG 10
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#define MAXERRORS 10
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static inline void write_byte(int fd, char cc) {
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write(fd, &cc, 1);
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}
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static inline void write_flush(int fd) {
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tcdrain(fd);
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}
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static inline void read_flush(int fd) {
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tcflush(fd, TCIFLUSH);
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}
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static int read_byte(int fd, unsigned int timeout) {
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char buf[1];
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int n;
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alarm(timeout);
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n = read(fd, &buf, 1);
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alarm(0);
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if (n == 1)
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return buf[0] & 0xff;
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else
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return -1;
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}
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static int receive(char *error_buf, size_t error_buf_size,
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int ttyfd, int filefd)
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{
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char blockBuf[1024];
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unsigned int errors = 0;
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unsigned int wantBlockNo = 1;
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unsigned int length = 0;
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int docrc = 1;
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char nak = 'C';
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unsigned int timeout = TIMEOUT_LONG;
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#define note_error(fmt,args...) \
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snprintf(error_buf, error_buf_size, fmt,##args)
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read_flush(ttyfd);
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/* Ask for CRC; if we get errors, we will go with checksum */
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write_byte(ttyfd, nak);
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write_flush(ttyfd);
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for (;;) {
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int blockBegin;
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int blockNo, blockNoOnesCompl;
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int blockLength;
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int cksum = 0;
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int crcHi = 0;
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int crcLo = 0;
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blockBegin = read_byte(ttyfd, timeout);
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if (blockBegin < 0)
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goto timeout;
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timeout = TIMEOUT;
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nak = NAK;
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switch (blockBegin) {
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case SOH:
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case STX:
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break;
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case EOT:
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write_byte(ttyfd, ACK);
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write_flush(ttyfd);
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goto done;
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default:
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goto error;
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}
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/* block no */
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blockNo = read_byte(ttyfd, TIMEOUT);
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if (blockNo < 0)
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goto timeout;
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/* block no one's compliment */
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blockNoOnesCompl = read_byte(ttyfd, TIMEOUT);
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if (blockNoOnesCompl < 0)
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goto timeout;
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if (blockNo != (255 - blockNoOnesCompl)) {
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note_error("bad block ones compl");
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goto error;
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}
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blockLength = (blockBegin == SOH) ? 128 : 1024;
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{
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int i;
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for (i = 0; i < blockLength; i++) {
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int cc = read_byte(ttyfd, TIMEOUT);
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if (cc < 0)
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goto timeout;
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blockBuf[i] = cc;
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}
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}
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if (docrc) {
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crcHi = read_byte(ttyfd, TIMEOUT);
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if (crcHi < 0)
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goto timeout;
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crcLo = read_byte(ttyfd, TIMEOUT);
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if (crcLo < 0)
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goto timeout;
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} else {
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cksum = read_byte(ttyfd, TIMEOUT);
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if (cksum < 0)
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goto timeout;
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}
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if (blockNo == ((wantBlockNo - 1) & 0xff)) {
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/* a repeat of the last block is ok, just ignore it. */
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/* this also ignores the initial block 0 which is */
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/* meta data. */
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goto next;
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} else if (blockNo != (wantBlockNo & 0xff)) {
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note_error("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo);
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goto error;
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}
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if (docrc) {
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int crc = 0;
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int i, j;
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int expectedCrcHi;
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int expectedCrcLo;
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for (i = 0; i < blockLength; i++) {
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crc = crc ^ (int) blockBuf[i] << 8;
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for (j = 0; j < 8; j++)
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if (crc & 0x8000)
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crc = crc << 1 ^ 0x1021;
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else
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crc = crc << 1;
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}
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expectedCrcHi = (crc >> 8) & 0xff;
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expectedCrcLo = crc & 0xff;
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if ((crcHi != expectedCrcHi) ||
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(crcLo != expectedCrcLo)) {
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note_error("crc error, expected 0x%02x 0x%02x, got 0x%02x 0x%02x", expectedCrcHi, expectedCrcLo, crcHi, crcLo);
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goto error;
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}
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} else {
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unsigned char expectedCksum = 0;
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int i;
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for (i = 0; i < blockLength; i++)
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expectedCksum += blockBuf[i];
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if (cksum != expectedCksum) {
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note_error("checksum error, expected 0x%02x, got 0x%02x", expectedCksum, cksum);
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goto error;
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}
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}
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wantBlockNo++;
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length += blockLength;
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if (bb_full_write(filefd, blockBuf, blockLength) < 0) {
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note_error("write to file failed: %m");
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goto fatal;
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}
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next:
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errors = 0;
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write_byte(ttyfd, ACK);
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write_flush(ttyfd);
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continue;
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error:
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timeout:
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errors++;
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if (errors == MAXERRORS) {
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/* Abort */
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int i;
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// if using crc, try again w/o crc
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if (nak == 'C') {
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nak = NAK;
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errors = 0;
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docrc = 0;
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goto timeout;
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}
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note_error("too many errors; giving up");
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fatal:
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for (i = 0; i < 5; i ++)
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write_byte(ttyfd, CAN);
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for (i = 0; i < 5; i ++)
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write_byte(ttyfd, BS);
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write_flush(ttyfd);
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return -1;
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}
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read_flush(ttyfd);
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write_byte(ttyfd, nak);
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write_flush(ttyfd);
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}
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done:
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return length;
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#undef note_error
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}
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static void sigalrm_handler(int ATTRIBUTE_UNUSED signum)
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{
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}
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int rx_main(int argc, char **argv)
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{
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char *fn;
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int ttyfd, filefd;
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struct termios tty, orig_tty;
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struct sigaction act;
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int n;
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char error_buf[256];
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if (argc != 2)
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bb_show_usage();
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fn = argv[1];
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ttyfd = open("/dev/tty", O_RDWR);
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if (ttyfd < 0)
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bb_error_msg_and_die("%s: open on /dev/tty failed: %m\n", argv[0]);
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filefd = open(fn, O_RDWR|O_CREAT|O_TRUNC, 0666);
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if (filefd < 0)
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bb_error_msg_and_die("%s: open on %s failed: %m\n", argv[0], fn);
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if (tcgetattr(ttyfd, &tty) < 0)
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bb_error_msg_and_die("%s: tcgetattr failed: %m\n", argv[0]);
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orig_tty = tty;
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cfmakeraw(&tty);
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tcsetattr(ttyfd, TCSAFLUSH, &tty);
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memset(&act, 0, sizeof(act));
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act.sa_handler = sigalrm_handler;
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sigaction(SIGALRM, &act, 0);
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n = receive(error_buf, sizeof(error_buf), ttyfd, filefd);
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close(filefd);
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tcsetattr(ttyfd, TCSAFLUSH, &orig_tty);
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if (n < 0)
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bb_error_msg_and_die("\n%s: receive failed:\n %s\n",
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argv[0], error_buf);
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bb_fflush_stdout_and_exit(EXIT_SUCCESS);
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}
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/*
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Local Variables:
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c-file-style: "linux"
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c-basic-offset: 4
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tab-width: 4
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End:
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*/
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