[821] | 1 | /* vi: set sw=4 ts=4: */
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[2725] | 2 | /*
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[821] | 3 | * Copyright: Copyright (C) 2001, Hewlett-Packard Company
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| 4 | * Author: Christopher Hoover <ch@hpl.hp.com>
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| 5 | * Description: xmodem functionality for uploading of kernels
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| 6 | * and the like
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| 7 | * Created at: Thu Dec 20 01:58:08 PST 2001
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| 8 | *
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[2725] | 9 | * xmodem functionality for uploading of kernels and the like
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| 10 | *
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[821] | 11 | * Copyright (C) 2001 Hewlett-Packard Laboratories
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| 12 | *
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[2725] | 13 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[821] | 14 | *
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| 15 | * This was originally written for blob and then adapted for busybox.
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| 16 | */
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| 17 |
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[3232] | 18 | //usage:#define rx_trivial_usage
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| 19 | //usage: "FILE"
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| 20 | //usage:#define rx_full_usage "\n\n"
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| 21 | //usage: "Receive a file using the xmodem protocol"
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| 22 | //usage:
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| 23 | //usage:#define rx_example_usage
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| 24 | //usage: "$ rx /tmp/foo\n"
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| 25 |
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[1765] | 26 | #include "libbb.h"
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[821] | 27 |
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| 28 | #define SOH 0x01
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| 29 | #define STX 0x02
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| 30 | #define EOT 0x04
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| 31 | #define ACK 0x06
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| 32 | #define NAK 0x15
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| 33 | #define BS 0x08
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[2725] | 34 | #define PAD 0x1A
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[821] | 35 |
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| 36 | /*
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| 37 | Cf:
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| 38 | http://www.textfiles.com/apple/xmodem
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| 39 | http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt
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| 40 | http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt
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| 41 | http://www.phys.washington.edu/~belonis/xmodem/modmprot.col
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| 42 | */
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| 43 |
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| 44 | #define TIMEOUT 1
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| 45 | #define TIMEOUT_LONG 10
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| 46 | #define MAXERRORS 10
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| 47 |
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[2725] | 48 | #define read_fd STDIN_FILENO
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| 49 | #define write_fd STDOUT_FILENO
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| 50 |
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| 51 | static int read_byte(unsigned timeout)
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[1765] | 52 | {
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[2725] | 53 | unsigned char buf;
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[821] | 54 | int n;
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| 55 |
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| 56 | alarm(timeout);
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[2725] | 57 | /* NOT safe_read! We want ALRM to interrupt us */
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| 58 | n = read(read_fd, &buf, 1);
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[821] | 59 | alarm(0);
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| 60 | if (n == 1)
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[2725] | 61 | return buf;
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| 62 | return -1;
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[821] | 63 | }
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| 64 |
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[2725] | 65 | static int receive(/*int read_fd, */int file_fd)
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[821] | 66 | {
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[2725] | 67 | unsigned char blockBuf[1024];
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| 68 | unsigned blockLength = 0;
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| 69 | unsigned errors = 0;
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| 70 | unsigned wantBlockNo = 1;
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| 71 | unsigned length = 0;
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| 72 | int do_crc = 1;
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| 73 | char reply_char;
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| 74 | unsigned timeout = TIMEOUT_LONG;
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[821] | 75 |
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| 76 | /* Flush pending input */
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[2725] | 77 | tcflush(read_fd, TCIFLUSH);
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[821] | 78 |
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| 79 | /* Ask for CRC; if we get errors, we will go with checksum */
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[2725] | 80 | reply_char = 'C';
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| 81 | full_write(write_fd, &reply_char, 1);
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[821] | 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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[2725] | 86 | int cksum_or_crc;
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| 87 | int expected;
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| 88 | int i, j;
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[821] | 89 |
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[2725] | 90 | blockBegin = read_byte(timeout);
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[821] | 91 | if (blockBegin < 0)
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| 92 | goto timeout;
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| 93 |
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[2725] | 94 | /* If last block, remove padding */
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| 95 | if (blockBegin == EOT) {
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| 96 | /* Data blocks can be padded with ^Z characters */
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| 97 | /* This code tries to detect and remove them */
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| 98 | if (blockLength >= 3
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| 99 | && blockBuf[blockLength - 1] == PAD
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| 100 | && blockBuf[blockLength - 2] == PAD
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| 101 | && blockBuf[blockLength - 3] == PAD
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| 102 | ) {
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| 103 | while (blockLength
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| 104 | && blockBuf[blockLength - 1] == PAD
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| 105 | ) {
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| 106 | blockLength--;
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| 107 | }
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| 108 | }
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| 109 | }
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| 110 | /* Write previously received block */
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[3232] | 111 | errno = 0;
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| 112 | if (full_write(file_fd, blockBuf, blockLength) != blockLength) {
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| 113 | bb_perror_msg(bb_msg_write_error);
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| 114 | goto fatal;
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[2725] | 115 | }
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| 116 |
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[821] | 117 | timeout = TIMEOUT;
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[2725] | 118 | reply_char = NAK;
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[821] | 119 |
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| 120 | switch (blockBegin) {
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| 121 | case SOH:
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| 122 | case STX:
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| 123 | break;
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| 124 | case EOT:
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[2725] | 125 | reply_char = ACK;
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| 126 | full_write(write_fd, &reply_char, 1);
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| 127 | return length;
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[821] | 128 | default:
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| 129 | goto error;
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| 130 | }
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| 131 |
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[2725] | 132 | /* Block no */
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| 133 | blockNo = read_byte(TIMEOUT);
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[821] | 134 | if (blockNo < 0)
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| 135 | goto timeout;
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| 136 |
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[2725] | 137 | /* Block no, in one's complement form */
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| 138 | blockNoOnesCompl = read_byte(TIMEOUT);
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[821] | 139 | if (blockNoOnesCompl < 0)
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| 140 | goto timeout;
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| 141 |
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| 142 | if (blockNo != (255 - blockNoOnesCompl)) {
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[2725] | 143 | bb_error_msg("bad block ones compl");
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[821] | 144 | goto error;
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| 145 | }
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| 146 |
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| 147 | blockLength = (blockBegin == SOH) ? 128 : 1024;
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| 148 |
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[2725] | 149 | for (i = 0; i < blockLength; i++) {
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| 150 | int cc = read_byte(TIMEOUT);
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| 151 | if (cc < 0)
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| 152 | goto timeout;
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| 153 | blockBuf[i] = cc;
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[821] | 154 | }
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| 155 |
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[3232] | 156 | cksum_or_crc = read_byte(TIMEOUT);
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| 157 | if (cksum_or_crc < 0)
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| 158 | goto timeout;
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[2725] | 159 | if (do_crc) {
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| 160 | cksum_or_crc = (cksum_or_crc << 8) | read_byte(TIMEOUT);
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| 161 | if (cksum_or_crc < 0)
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[821] | 162 | goto timeout;
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| 163 | }
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| 164 |
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| 165 | if (blockNo == ((wantBlockNo - 1) & 0xff)) {
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| 166 | /* a repeat of the last block is ok, just ignore it. */
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| 167 | /* this also ignores the initial block 0 which is */
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| 168 | /* meta data. */
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[3232] | 169 | blockLength = 0;
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[821] | 170 | goto next;
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[2725] | 171 | }
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| 172 | if (blockNo != (wantBlockNo & 0xff)) {
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| 173 | bb_error_msg("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo);
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[821] | 174 | goto error;
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| 175 | }
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| 176 |
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[2725] | 177 | expected = 0;
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| 178 | if (do_crc) {
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[821] | 179 | for (i = 0; i < blockLength; i++) {
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[2725] | 180 | expected = expected ^ blockBuf[i] << 8;
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| 181 | for (j = 0; j < 8; j++) {
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| 182 | if (expected & 0x8000)
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| 183 | expected = (expected << 1) ^ 0x1021;
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[821] | 184 | else
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[2725] | 185 | expected = (expected << 1);
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| 186 | }
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[821] | 187 | }
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[2725] | 188 | expected &= 0xffff;
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[821] | 189 | } else {
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| 190 | for (i = 0; i < blockLength; i++)
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[2725] | 191 | expected += blockBuf[i];
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| 192 | expected &= 0xff;
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[821] | 193 | }
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[2725] | 194 | if (cksum_or_crc != expected) {
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| 195 | bb_error_msg(do_crc ? "crc error, expected 0x%04x, got 0x%04x"
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[3232] | 196 | : "checksum error, expected 0x%02x, got 0x%02x",
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| 197 | expected, cksum_or_crc);
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[2725] | 198 | goto error;
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| 199 | }
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[821] | 200 |
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| 201 | wantBlockNo++;
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| 202 | length += blockLength;
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[2725] | 203 | next:
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[821] | 204 | errors = 0;
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[2725] | 205 | reply_char = ACK;
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| 206 | full_write(write_fd, &reply_char, 1);
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[821] | 207 | continue;
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[2725] | 208 | error:
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| 209 | timeout:
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[3232] | 210 | blockLength = 0;
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[821] | 211 | errors++;
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| 212 | if (errors == MAXERRORS) {
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| 213 | /* Abort */
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| 214 |
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[2725] | 215 | /* If were asking for crc, try again w/o crc */
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| 216 | if (reply_char == 'C') {
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| 217 | reply_char = NAK;
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[821] | 218 | errors = 0;
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[2725] | 219 | do_crc = 0;
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[821] | 220 | goto timeout;
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| 221 | }
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[2725] | 222 | bb_error_msg("too many errors; giving up");
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| 223 | fatal:
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| 224 | /* 5 CAN followed by 5 BS. Don't try too hard... */
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| 225 | safe_write(write_fd, "\030\030\030\030\030\010\010\010\010\010", 10);
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[821] | 226 | return -1;
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| 227 | }
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| 228 |
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| 229 | /* Flush pending input */
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[2725] | 230 | tcflush(read_fd, TCIFLUSH);
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[821] | 231 |
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[2725] | 232 | full_write(write_fd, &reply_char, 1);
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| 233 | } /* for (;;) */
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[821] | 234 | }
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| 235 |
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[2725] | 236 | static void sigalrm_handler(int UNUSED_PARAM signum)
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[821] | 237 | {
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| 238 | }
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| 239 |
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[2725] | 240 | int rx_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 241 | int rx_main(int argc UNUSED_PARAM, char **argv)
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[821] | 242 | {
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| 243 | struct termios tty, orig_tty;
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[2725] | 244 | int termios_err;
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| 245 | int file_fd;
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[821] | 246 | int n;
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| 247 |
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[2725] | 248 | /* Disabled by vda:
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| 249 | * why we can't receive from stdin? Why we *require*
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| 250 | * controlling tty?? */
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| 251 | /*read_fd = xopen(CURRENT_TTY, O_RDWR);*/
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| 252 | file_fd = xopen(single_argv(argv), O_RDWR|O_CREAT|O_TRUNC);
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[821] | 253 |
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[2725] | 254 | termios_err = tcgetattr(read_fd, &tty);
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| 255 | if (termios_err == 0) {
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| 256 | orig_tty = tty;
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| 257 | cfmakeraw(&tty);
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| 258 | tcsetattr(read_fd, TCSAFLUSH, &tty);
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| 259 | }
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[821] | 260 |
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[2725] | 261 | /* No SA_RESTART: we want ALRM to interrupt read() */
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| 262 | signal_no_SA_RESTART_empty_mask(SIGALRM, sigalrm_handler);
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[821] | 263 |
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[2725] | 264 | n = receive(file_fd);
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[821] | 265 |
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[2725] | 266 | if (termios_err == 0)
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| 267 | tcsetattr(read_fd, TCSAFLUSH, &orig_tty);
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| 268 | if (ENABLE_FEATURE_CLEAN_UP)
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| 269 | close(file_fd);
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| 270 | fflush_stdout_and_exit(n >= 0);
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[821] | 271 | }
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