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

Last change on this file since 3232 was 3232, checked in by Bruno Cornec, 10 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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