[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 | * Copyright: Copyright (C) 2001, Hewlett-Packard Company
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| 5 | * Author: Christopher Hoover <ch@hpl.hp.com>
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| 6 | * Description: xmodem functionality for uploading of kernels
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| 7 | * and the like
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| 8 | * Created at: Thu Dec 20 01:58:08 PST 2001
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| 9 | *-----------------------------------------------------------------------*/
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| 10 | /*
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| 11 | * xmodem.c: xmodem functionality for uploading of kernels and
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| 12 | * the like
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| 13 | *
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| 14 | * Copyright (C) 2001 Hewlett-Packard Laboratories
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| 15 | *
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| 16 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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| 17 | *
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| 18 | * This was originally written for blob and then adapted for busybox.
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| 19 | *
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| 20 | */
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| 21 |
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[1765] | 22 | #include "libbb.h"
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[821] | 23 |
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| 24 | #define SOH 0x01
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| 25 | #define STX 0x02
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| 26 | #define EOT 0x04
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| 27 | #define ACK 0x06
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| 28 | #define NAK 0x15
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| 29 | #define BS 0x08
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| 30 |
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| 31 | /*
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| 32 |
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| 33 | Cf:
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| 34 |
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| 35 | http://www.textfiles.com/apple/xmodem
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| 36 | http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt
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| 37 | http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt
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| 38 | http://www.phys.washington.edu/~belonis/xmodem/modmprot.col
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| 39 |
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| 40 | */
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| 41 |
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| 42 | #define TIMEOUT 1
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| 43 | #define TIMEOUT_LONG 10
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| 44 | #define MAXERRORS 10
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| 45 |
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[1765] | 46 | static int read_byte(int fd, unsigned int timeout)
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| 47 | {
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[821] | 48 | char buf[1];
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| 49 | int n;
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| 50 |
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| 51 | alarm(timeout);
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| 52 |
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| 53 | n = read(fd, &buf, 1);
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| 54 |
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| 55 | alarm(0);
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| 56 |
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| 57 | if (n == 1)
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| 58 | return buf[0] & 0xff;
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| 59 | else
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| 60 | return -1;
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| 61 | }
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| 62 |
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| 63 | static int receive(char *error_buf, size_t error_buf_size,
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| 64 | int ttyfd, int filefd)
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| 65 | {
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| 66 | char blockBuf[1024];
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| 67 | unsigned int errors = 0;
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| 68 | unsigned int wantBlockNo = 1;
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| 69 | unsigned int length = 0;
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| 70 | int docrc = 1;
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| 71 | char nak = 'C';
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| 72 | unsigned int timeout = TIMEOUT_LONG;
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| 73 |
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| 74 | #define note_error(fmt,args...) \
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| 75 | snprintf(error_buf, error_buf_size, fmt,##args)
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| 76 |
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| 77 | /* Flush pending input */
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| 78 | tcflush(ttyfd, TCIFLUSH);
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| 79 |
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| 80 | /* Ask for CRC; if we get errors, we will go with checksum */
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| 81 | write(ttyfd, &nak, 1);
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| 82 |
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| 83 | for (;;) {
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| 84 | int blockBegin;
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| 85 | int blockNo, blockNoOnesCompl;
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| 86 | int blockLength;
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| 87 | int cksum = 0;
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| 88 | int crcHi = 0;
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| 89 | int crcLo = 0;
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| 90 |
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| 91 | blockBegin = read_byte(ttyfd, timeout);
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| 92 | if (blockBegin < 0)
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| 93 | goto timeout;
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| 94 |
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| 95 | timeout = TIMEOUT;
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| 96 | nak = NAK;
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| 97 |
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| 98 | switch (blockBegin) {
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| 99 | case SOH:
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| 100 | case STX:
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| 101 | break;
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| 102 |
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| 103 | case EOT:
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| 104 | nak = ACK;
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| 105 | write(ttyfd, &nak, 1);
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| 106 | goto done;
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| 107 |
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| 108 | default:
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| 109 | goto error;
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| 110 | }
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| 111 |
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| 112 | /* block no */
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| 113 | blockNo = read_byte(ttyfd, TIMEOUT);
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| 114 | if (blockNo < 0)
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| 115 | goto timeout;
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| 116 |
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| 117 | /* block no one's compliment */
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| 118 | blockNoOnesCompl = read_byte(ttyfd, TIMEOUT);
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| 119 | if (blockNoOnesCompl < 0)
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| 120 | goto timeout;
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| 121 |
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| 122 | if (blockNo != (255 - blockNoOnesCompl)) {
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| 123 | note_error("bad block ones compl");
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| 124 | goto error;
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| 125 | }
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| 126 |
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| 127 | blockLength = (blockBegin == SOH) ? 128 : 1024;
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| 128 |
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| 129 | {
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| 130 | int i;
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| 131 |
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| 132 | for (i = 0; i < blockLength; i++) {
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| 133 | int cc = read_byte(ttyfd, TIMEOUT);
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| 134 | if (cc < 0)
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| 135 | goto timeout;
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| 136 | blockBuf[i] = cc;
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| 137 | }
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| 138 | }
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| 139 |
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| 140 | if (docrc) {
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| 141 | crcHi = read_byte(ttyfd, TIMEOUT);
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| 142 | if (crcHi < 0)
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| 143 | goto timeout;
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| 144 |
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| 145 | crcLo = read_byte(ttyfd, TIMEOUT);
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| 146 | if (crcLo < 0)
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| 147 | goto timeout;
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| 148 | } else {
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| 149 | cksum = read_byte(ttyfd, TIMEOUT);
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| 150 | if (cksum < 0)
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| 151 | goto timeout;
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| 152 | }
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| 153 |
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| 154 | if (blockNo == ((wantBlockNo - 1) & 0xff)) {
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| 155 | /* a repeat of the last block is ok, just ignore it. */
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| 156 | /* this also ignores the initial block 0 which is */
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| 157 | /* meta data. */
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| 158 | goto next;
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| 159 | } else if (blockNo != (wantBlockNo & 0xff)) {
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| 160 | note_error("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo);
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| 161 | goto error;
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| 162 | }
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| 163 |
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| 164 | if (docrc) {
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| 165 | int crc = 0;
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| 166 | int i, j;
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| 167 | int expectedCrcHi;
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| 168 | int expectedCrcLo;
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| 169 |
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| 170 | for (i = 0; i < blockLength; i++) {
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| 171 | crc = crc ^ (int) blockBuf[i] << 8;
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| 172 | for (j = 0; j < 8; j++)
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| 173 | if (crc & 0x8000)
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| 174 | crc = crc << 1 ^ 0x1021;
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| 175 | else
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| 176 | crc = crc << 1;
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| 177 | }
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| 178 |
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| 179 | expectedCrcHi = (crc >> 8) & 0xff;
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| 180 | expectedCrcLo = crc & 0xff;
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| 181 |
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| 182 | if ((crcHi != expectedCrcHi) ||
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| 183 | (crcLo != expectedCrcLo)) {
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| 184 | note_error("crc error, expected 0x%02x 0x%02x, got 0x%02x 0x%02x", expectedCrcHi, expectedCrcLo, crcHi, crcLo);
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| 185 | goto error;
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| 186 | }
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| 187 | } else {
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| 188 | unsigned char expectedCksum = 0;
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| 189 | int i;
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| 190 |
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| 191 | for (i = 0; i < blockLength; i++)
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| 192 | expectedCksum += blockBuf[i];
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| 193 |
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| 194 | if (cksum != expectedCksum) {
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| 195 | note_error("checksum error, expected 0x%02x, got 0x%02x", expectedCksum, cksum);
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| 196 | goto error;
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| 197 | }
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| 198 | }
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| 199 |
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| 200 | wantBlockNo++;
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| 201 | length += blockLength;
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| 202 |
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[1765] | 203 | if (full_write(filefd, blockBuf, blockLength) < 0) {
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[821] | 204 | note_error("write to file failed: %m");
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| 205 | goto fatal;
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| 206 | }
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| 207 |
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| 208 | next:
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| 209 | errors = 0;
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| 210 | nak = ACK;
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| 211 | write(ttyfd, &nak, 1);
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| 212 | continue;
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| 213 |
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| 214 | error:
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| 215 | timeout:
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| 216 | errors++;
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| 217 | if (errors == MAXERRORS) {
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| 218 | /* Abort */
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| 219 |
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| 220 | // if using crc, try again w/o crc
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| 221 | if (nak == 'C') {
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| 222 | nak = NAK;
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| 223 | errors = 0;
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| 224 | docrc = 0;
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| 225 | goto timeout;
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| 226 | }
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| 227 |
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| 228 | note_error("too many errors; giving up");
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| 229 |
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| 230 | fatal:
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| 231 | /* 5 CAN followed by 5 BS */
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| 232 | write(ttyfd, "\030\030\030\030\030\010\010\010\010\010", 10);
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| 233 | return -1;
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| 234 | }
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| 235 |
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| 236 | /* Flush pending input */
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| 237 | tcflush(ttyfd, TCIFLUSH);
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| 238 |
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| 239 | write(ttyfd, &nak, 1);
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| 240 | }
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| 241 |
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| 242 | done:
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| 243 | return length;
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| 244 |
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| 245 | #undef note_error
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| 246 | }
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| 247 |
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| 248 | static void sigalrm_handler(int ATTRIBUTE_UNUSED signum)
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| 249 | {
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| 250 | }
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| 251 |
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[1765] | 252 | int rx_main(int argc, char **argv);
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[821] | 253 | int rx_main(int argc, char **argv)
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| 254 | {
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| 255 | char *fn;
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| 256 | int ttyfd, filefd;
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| 257 | struct termios tty, orig_tty;
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| 258 | struct sigaction act;
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| 259 | int n;
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| 260 | char error_buf[256];
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| 261 |
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| 262 | if (argc != 2)
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| 263 | bb_show_usage();
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| 264 |
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| 265 | fn = argv[1];
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[1765] | 266 | ttyfd = xopen(CURRENT_TTY, O_RDWR);
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| 267 | filefd = xopen(fn, O_RDWR|O_CREAT|O_TRUNC);
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[821] | 268 |
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| 269 | if (tcgetattr(ttyfd, &tty) < 0)
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[1765] | 270 | bb_perror_msg_and_die("tcgetattr");
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[821] | 271 |
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| 272 | orig_tty = tty;
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| 273 |
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| 274 | cfmakeraw(&tty);
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| 275 | tcsetattr(ttyfd, TCSAFLUSH, &tty);
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| 276 |
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| 277 | memset(&act, 0, sizeof(act));
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| 278 | act.sa_handler = sigalrm_handler;
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| 279 | sigaction(SIGALRM, &act, 0);
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| 280 |
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| 281 | n = receive(error_buf, sizeof(error_buf), ttyfd, filefd);
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| 282 |
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| 283 | close(filefd);
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| 284 |
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| 285 | tcsetattr(ttyfd, TCSAFLUSH, &orig_tty);
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| 286 |
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| 287 | if (n < 0)
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[1765] | 288 | bb_error_msg_and_die("\nreceive failed:\n %s", error_buf);
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[821] | 289 |
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[1765] | 290 | fflush_stdout_and_exit(EXIT_SUCCESS);
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[821] | 291 | }
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