--- /dev/null
+/*-------------------------------------------------------------------------
+ * 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:
+*/
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