[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*-------------------------------------------------------------------------
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| 3 | * Filename: xmodem.c
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| 4 | * Version: $Id: rx.c,v 1.2 2004/03/15 08:28:46 andersen Exp $
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| 5 | * Copyright: Copyright (C) 2001, Hewlett-Packard Company
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| 6 | * Author: Christopher Hoover <ch@hpl.hp.com>
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| 7 | * Description: xmodem functionality for uploading of kernels
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| 8 | * and the like
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| 9 | * Created at: Thu Dec 20 01:58:08 PST 2001
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| 10 | *-----------------------------------------------------------------------*/
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| 11 | /*
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| 12 | * xmodem.c: xmodem functionality for uploading of kernels and
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| 13 | * the like
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| 14 | *
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| 15 | * Copyright (C) 2001 Hewlett-Packard Laboratories
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| 16 | *
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| 17 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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| 18 | *
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| 19 | * This was originally written for blob and then adapted for busybox.
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| 20 | *
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| 21 | */
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| 22 |
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| 23 | #include "busybox.h"
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| 24 | #include <stdlib.h>
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| 25 | #include <stdarg.h>
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| 26 | #include <stdio.h>
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| 27 | #include <unistd.h>
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| 28 | #include <errno.h>
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| 29 | #include <termios.h>
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| 30 | #include <signal.h>
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| 31 | #include <sys/types.h>
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| 32 | #include <sys/stat.h>
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| 33 | #include <fcntl.h>
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| 34 | #include <string.h>
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| 35 |
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| 36 |
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| 37 | #define SOH 0x01
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| 38 | #define STX 0x02
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| 39 | #define EOT 0x04
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| 40 | #define ACK 0x06
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| 41 | #define NAK 0x15
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| 42 | #define BS 0x08
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| 43 |
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| 44 | /*
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| 45 |
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| 46 | Cf:
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| 47 |
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| 48 | http://www.textfiles.com/apple/xmodem
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| 49 | http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt
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| 50 | http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt
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| 51 | http://www.phys.washington.edu/~belonis/xmodem/modmprot.col
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| 52 |
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| 53 | */
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| 54 |
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| 55 | #define TIMEOUT 1
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| 56 | #define TIMEOUT_LONG 10
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| 57 | #define MAXERRORS 10
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| 58 |
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| 59 | static int read_byte(int fd, unsigned int timeout) {
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| 60 | char buf[1];
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| 61 | int n;
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| 62 |
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| 63 | alarm(timeout);
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| 64 |
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| 65 | n = read(fd, &buf, 1);
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| 66 |
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| 67 | alarm(0);
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| 68 |
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| 69 | if (n == 1)
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| 70 | return buf[0] & 0xff;
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| 71 | else
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| 72 | return -1;
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| 73 | }
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| 74 |
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| 75 | static int receive(char *error_buf, size_t error_buf_size,
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| 76 | int ttyfd, int filefd)
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| 77 | {
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| 78 | char blockBuf[1024];
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| 79 | unsigned int errors = 0;
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| 80 | unsigned int wantBlockNo = 1;
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| 81 | unsigned int length = 0;
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| 82 | int docrc = 1;
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| 83 | char nak = 'C';
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| 84 | unsigned int timeout = TIMEOUT_LONG;
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| 85 |
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| 86 | #define note_error(fmt,args...) \
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| 87 | snprintf(error_buf, error_buf_size, fmt,##args)
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| 88 |
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| 89 | /* Flush pending input */
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| 90 | tcflush(ttyfd, TCIFLUSH);
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| 91 |
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| 92 | /* Ask for CRC; if we get errors, we will go with checksum */
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| 93 | write(ttyfd, &nak, 1);
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| 94 |
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| 95 | for (;;) {
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| 96 | int blockBegin;
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| 97 | int blockNo, blockNoOnesCompl;
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| 98 | int blockLength;
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| 99 | int cksum = 0;
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| 100 | int crcHi = 0;
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| 101 | int crcLo = 0;
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| 102 |
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| 103 | blockBegin = read_byte(ttyfd, timeout);
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| 104 | if (blockBegin < 0)
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| 105 | goto timeout;
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| 106 |
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| 107 | timeout = TIMEOUT;
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| 108 | nak = NAK;
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| 109 |
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| 110 | switch (blockBegin) {
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| 111 | case SOH:
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| 112 | case STX:
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| 113 | break;
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| 114 |
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| 115 | case EOT:
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| 116 | nak = ACK;
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| 117 | write(ttyfd, &nak, 1);
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| 118 | goto done;
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| 119 |
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| 120 | default:
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| 121 | goto error;
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| 122 | }
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| 123 |
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| 124 | /* block no */
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| 125 | blockNo = read_byte(ttyfd, TIMEOUT);
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| 126 | if (blockNo < 0)
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| 127 | goto timeout;
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| 128 |
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| 129 | /* block no one's compliment */
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| 130 | blockNoOnesCompl = read_byte(ttyfd, TIMEOUT);
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| 131 | if (blockNoOnesCompl < 0)
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| 132 | goto timeout;
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| 133 |
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| 134 | if (blockNo != (255 - blockNoOnesCompl)) {
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| 135 | note_error("bad block ones compl");
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| 136 | goto error;
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| 137 | }
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| 138 |
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| 139 | blockLength = (blockBegin == SOH) ? 128 : 1024;
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| 140 |
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| 141 | {
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| 142 | int i;
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| 143 |
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| 144 | for (i = 0; i < blockLength; i++) {
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| 145 | int cc = read_byte(ttyfd, TIMEOUT);
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| 146 | if (cc < 0)
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| 147 | goto timeout;
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| 148 | blockBuf[i] = cc;
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| 149 | }
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| 150 | }
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| 151 |
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| 152 | if (docrc) {
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| 153 | crcHi = read_byte(ttyfd, TIMEOUT);
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| 154 | if (crcHi < 0)
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| 155 | goto timeout;
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| 156 |
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| 157 | crcLo = read_byte(ttyfd, TIMEOUT);
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| 158 | if (crcLo < 0)
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| 159 | goto timeout;
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| 160 | } else {
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| 161 | cksum = read_byte(ttyfd, TIMEOUT);
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| 162 | if (cksum < 0)
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| 163 | goto timeout;
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| 164 | }
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| 165 |
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| 166 | if (blockNo == ((wantBlockNo - 1) & 0xff)) {
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| 167 | /* a repeat of the last block is ok, just ignore it. */
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| 168 | /* this also ignores the initial block 0 which is */
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| 169 | /* meta data. */
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| 170 | goto next;
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| 171 | } else if (blockNo != (wantBlockNo & 0xff)) {
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| 172 | note_error("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo);
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| 173 | goto error;
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| 174 | }
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| 175 |
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| 176 | if (docrc) {
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| 177 | int crc = 0;
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| 178 | int i, j;
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| 179 | int expectedCrcHi;
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| 180 | int expectedCrcLo;
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| 181 |
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| 182 | for (i = 0; i < blockLength; i++) {
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| 183 | crc = crc ^ (int) blockBuf[i] << 8;
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| 184 | for (j = 0; j < 8; j++)
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| 185 | if (crc & 0x8000)
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| 186 | crc = crc << 1 ^ 0x1021;
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| 187 | else
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| 188 | crc = crc << 1;
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| 189 | }
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| 190 |
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| 191 | expectedCrcHi = (crc >> 8) & 0xff;
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| 192 | expectedCrcLo = crc & 0xff;
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| 193 |
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| 194 | if ((crcHi != expectedCrcHi) ||
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| 195 | (crcLo != expectedCrcLo)) {
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| 196 | note_error("crc error, expected 0x%02x 0x%02x, got 0x%02x 0x%02x", expectedCrcHi, expectedCrcLo, crcHi, crcLo);
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| 197 | goto error;
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| 198 | }
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| 199 | } else {
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| 200 | unsigned char expectedCksum = 0;
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| 201 | int i;
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| 202 |
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| 203 | for (i = 0; i < blockLength; i++)
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| 204 | expectedCksum += blockBuf[i];
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| 205 |
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| 206 | if (cksum != expectedCksum) {
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| 207 | note_error("checksum error, expected 0x%02x, got 0x%02x", expectedCksum, cksum);
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| 208 | goto error;
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| 209 | }
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| 210 | }
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| 211 |
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| 212 | wantBlockNo++;
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| 213 | length += blockLength;
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| 214 |
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| 215 | if (bb_full_write(filefd, blockBuf, blockLength) < 0) {
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| 216 | note_error("write to file failed: %m");
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| 217 | goto fatal;
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| 218 | }
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| 219 |
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| 220 | next:
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| 221 | errors = 0;
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| 222 | nak = ACK;
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| 223 | write(ttyfd, &nak, 1);
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| 224 | continue;
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| 225 |
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| 226 | error:
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| 227 | timeout:
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| 228 | errors++;
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| 229 | if (errors == MAXERRORS) {
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| 230 | /* Abort */
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| 231 |
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| 232 | // if using crc, try again w/o crc
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| 233 | if (nak == 'C') {
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| 234 | nak = NAK;
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| 235 | errors = 0;
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| 236 | docrc = 0;
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| 237 | goto timeout;
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| 238 | }
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| 239 |
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| 240 | note_error("too many errors; giving up");
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| 241 |
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| 242 | fatal:
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| 243 | /* 5 CAN followed by 5 BS */
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| 244 | write(ttyfd, "\030\030\030\030\030\010\010\010\010\010", 10);
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| 245 | return -1;
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| 246 | }
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| 247 |
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| 248 | /* Flush pending input */
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| 249 | tcflush(ttyfd, TCIFLUSH);
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| 250 |
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| 251 | write(ttyfd, &nak, 1);
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| 252 | }
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| 253 |
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| 254 | done:
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| 255 | return length;
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| 256 |
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| 257 | #undef note_error
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| 258 | }
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| 259 |
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| 260 | static void sigalrm_handler(int ATTRIBUTE_UNUSED signum)
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| 261 | {
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| 262 | }
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| 263 |
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| 264 | int rx_main(int argc, char **argv)
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| 265 | {
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| 266 | char *fn;
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| 267 | int ttyfd, filefd;
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| 268 | struct termios tty, orig_tty;
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| 269 | struct sigaction act;
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| 270 | int n;
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| 271 | char error_buf[256];
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| 272 |
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| 273 | if (argc != 2)
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| 274 | bb_show_usage();
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| 275 |
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| 276 | fn = argv[1];
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| 277 | ttyfd = bb_xopen3(CURRENT_TTY, O_RDWR, 0);
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| 278 | filefd = bb_xopen3(fn, O_RDWR|O_CREAT|O_TRUNC, 0666);
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| 279 |
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| 280 | if (tcgetattr(ttyfd, &tty) < 0)
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| 281 | bb_error_msg_and_die("%s: tcgetattr failed: %m\n", argv[0]);
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| 282 |
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| 283 | orig_tty = tty;
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| 284 |
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| 285 | cfmakeraw(&tty);
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| 286 | tcsetattr(ttyfd, TCSAFLUSH, &tty);
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| 287 |
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| 288 | memset(&act, 0, sizeof(act));
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| 289 | act.sa_handler = sigalrm_handler;
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| 290 | sigaction(SIGALRM, &act, 0);
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| 291 |
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| 292 | n = receive(error_buf, sizeof(error_buf), ttyfd, filefd);
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| 293 |
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| 294 | close(filefd);
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| 295 |
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| 296 | tcsetattr(ttyfd, TCSAFLUSH, &orig_tty);
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| 297 |
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| 298 | if (n < 0)
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| 299 | bb_error_msg_and_die("\n%s: receive failed:\n %s\n",
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| 300 | argv[0], error_buf);
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| 301 |
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| 302 | bb_fflush_stdout_and_exit(EXIT_SUCCESS);
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| 303 | }
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