/*------------------------------------------------------------------------- * Filename: xmodem.c * Version: $Id: rx.c,v 1.2 2004/03/15 08:28:46 andersen 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: */