source: branches/3.2/mindi-busybox/miscutils/rx.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 6.1 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Copyright:     Copyright (C) 2001, Hewlett-Packard Company
4 * Author:        Christopher Hoover <ch@hpl.hp.com>
5 * Description:   xmodem functionality for uploading of kernels
6 *                and the like
7 * Created at:    Thu Dec 20 01:58:08 PST 2001
8 *
9 * xmodem functionality for uploading of kernels and the like
10 *
11 * Copyright (C) 2001 Hewlett-Packard Laboratories
12 *
13 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
14 *
15 * This was originally written for blob and then adapted for busybox.
16 */
17
18//usage:#define rx_trivial_usage
19//usage:       "FILE"
20//usage:#define rx_full_usage "\n\n"
21//usage:       "Receive a file using the xmodem protocol"
22//usage:
23//usage:#define rx_example_usage
24//usage:       "$ rx /tmp/foo\n"
25
26#include "libbb.h"
27
28#define SOH 0x01
29#define STX 0x02
30#define EOT 0x04
31#define ACK 0x06
32#define NAK 0x15
33#define BS  0x08
34#define PAD 0x1A
35
36/*
37Cf:
38  http://www.textfiles.com/apple/xmodem
39  http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt
40  http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt
41  http://www.phys.washington.edu/~belonis/xmodem/modmprot.col
42*/
43
44#define TIMEOUT 1
45#define TIMEOUT_LONG 10
46#define MAXERRORS 10
47
48#define read_fd  STDIN_FILENO
49#define write_fd STDOUT_FILENO
50
51static int read_byte(unsigned timeout)
52{
53    unsigned char buf;
54    int n;
55
56    alarm(timeout);
57    /* NOT safe_read! We want ALRM to interrupt us */
58    n = read(read_fd, &buf, 1);
59    alarm(0);
60    if (n == 1)
61        return buf;
62    return -1;
63}
64
65static int receive(/*int read_fd, */int file_fd)
66{
67    unsigned char blockBuf[1024];
68    unsigned blockLength = 0;
69    unsigned errors = 0;
70    unsigned wantBlockNo = 1;
71    unsigned length = 0;
72    int do_crc = 1;
73    char reply_char;
74    unsigned timeout = TIMEOUT_LONG;
75
76    /* Flush pending input */
77    tcflush(read_fd, TCIFLUSH);
78
79    /* Ask for CRC; if we get errors, we will go with checksum */
80    reply_char = 'C';
81    full_write(write_fd, &reply_char, 1);
82
83    for (;;) {
84        int blockBegin;
85        int blockNo, blockNoOnesCompl;
86        int cksum_or_crc;
87        int expected;
88        int i, j;
89
90        blockBegin = read_byte(timeout);
91        if (blockBegin < 0)
92            goto timeout;
93
94        /* If last block, remove padding */
95        if (blockBegin == EOT) {
96            /* Data blocks can be padded with ^Z characters */
97            /* This code tries to detect and remove them */
98            if (blockLength >= 3
99             && blockBuf[blockLength - 1] == PAD
100             && blockBuf[blockLength - 2] == PAD
101             && blockBuf[blockLength - 3] == PAD
102            ) {
103                while (blockLength
104                       && blockBuf[blockLength - 1] == PAD
105                ) {
106                    blockLength--;
107                }
108            }
109        }
110        /* Write previously received block */
111        errno = 0;
112        if (full_write(file_fd, blockBuf, blockLength) != blockLength) {
113            bb_perror_msg(bb_msg_write_error);
114            goto fatal;
115        }
116
117        timeout = TIMEOUT;
118        reply_char = NAK;
119
120        switch (blockBegin) {
121        case SOH:
122        case STX:
123            break;
124        case EOT:
125            reply_char = ACK;
126            full_write(write_fd, &reply_char, 1);
127            return length;
128        default:
129            goto error;
130        }
131
132        /* Block no */
133        blockNo = read_byte(TIMEOUT);
134        if (blockNo < 0)
135            goto timeout;
136
137        /* Block no, in one's complement form */
138        blockNoOnesCompl = read_byte(TIMEOUT);
139        if (blockNoOnesCompl < 0)
140            goto timeout;
141
142        if (blockNo != (255 - blockNoOnesCompl)) {
143            bb_error_msg("bad block ones compl");
144            goto error;
145        }
146
147        blockLength = (blockBegin == SOH) ? 128 : 1024;
148
149        for (i = 0; i < blockLength; i++) {
150            int cc = read_byte(TIMEOUT);
151            if (cc < 0)
152                goto timeout;
153            blockBuf[i] = cc;
154        }
155
156        cksum_or_crc = read_byte(TIMEOUT);
157        if (cksum_or_crc < 0)
158            goto timeout;
159        if (do_crc) {
160            cksum_or_crc = (cksum_or_crc << 8) | read_byte(TIMEOUT);
161            if (cksum_or_crc < 0)
162                goto timeout;
163        }
164
165        if (blockNo == ((wantBlockNo - 1) & 0xff)) {
166            /* a repeat of the last block is ok, just ignore it. */
167            /* this also ignores the initial block 0 which is */
168            /* meta data. */
169            blockLength = 0;
170            goto next;
171        }
172        if (blockNo != (wantBlockNo & 0xff)) {
173            bb_error_msg("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo);
174            goto error;
175        }
176
177        expected = 0;
178        if (do_crc) {
179            for (i = 0; i < blockLength; i++) {
180                expected = expected ^ blockBuf[i] << 8;
181                for (j = 0; j < 8; j++) {
182                    if (expected & 0x8000)
183                        expected = (expected << 1) ^ 0x1021;
184                    else
185                        expected = (expected << 1);
186                }
187            }
188            expected &= 0xffff;
189        } else {
190            for (i = 0; i < blockLength; i++)
191                expected += blockBuf[i];
192            expected &= 0xff;
193        }
194        if (cksum_or_crc != expected) {
195            bb_error_msg(do_crc ? "crc error, expected 0x%04x, got 0x%04x"
196                    : "checksum error, expected 0x%02x, got 0x%02x",
197                expected, cksum_or_crc);
198            goto error;
199        }
200
201        wantBlockNo++;
202        length += blockLength;
203 next:
204        errors = 0;
205        reply_char = ACK;
206        full_write(write_fd, &reply_char, 1);
207        continue;
208 error:
209 timeout:
210        blockLength = 0;
211        errors++;
212        if (errors == MAXERRORS) {
213            /* Abort */
214
215            /* If were asking for crc, try again w/o crc */
216            if (reply_char == 'C') {
217                reply_char = NAK;
218                errors = 0;
219                do_crc = 0;
220                goto timeout;
221            }
222            bb_error_msg("too many errors; giving up");
223 fatal:
224            /* 5 CAN followed by 5 BS. Don't try too hard... */
225            safe_write(write_fd, "\030\030\030\030\030\010\010\010\010\010", 10);
226            return -1;
227        }
228
229        /* Flush pending input */
230        tcflush(read_fd, TCIFLUSH);
231
232        full_write(write_fd, &reply_char, 1);
233    } /* for (;;) */
234}
235
236static void sigalrm_handler(int UNUSED_PARAM signum)
237{
238}
239
240int rx_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
241int rx_main(int argc UNUSED_PARAM, char **argv)
242{
243    struct termios tty, orig_tty;
244    int termios_err;
245    int file_fd;
246    int n;
247
248    /* Disabled by vda:
249     * why we can't receive from stdin? Why we *require*
250     * controlling tty?? */
251    /*read_fd = xopen(CURRENT_TTY, O_RDWR);*/
252    file_fd = xopen(single_argv(argv), O_RDWR|O_CREAT|O_TRUNC);
253
254    termios_err = tcgetattr(read_fd, &tty);
255    if (termios_err == 0) {
256        orig_tty = tty;
257        cfmakeraw(&tty);
258        tcsetattr(read_fd, TCSAFLUSH, &tty);
259    }
260
261    /* No SA_RESTART: we want ALRM to interrupt read() */
262    signal_no_SA_RESTART_empty_mask(SIGALRM, sigalrm_handler);
263
264    n = receive(file_fd);
265
266    if (termios_err == 0)
267        tcsetattr(read_fd, TCSAFLUSH, &orig_tty);
268    if (ENABLE_FEATURE_CLEAN_UP)
269        close(file_fd);
270    fflush_stdout_and_exit(n >= 0);
271}
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