blob: 2f47643cccdca89f21d8b736f30dac494bf2e47e
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 | /* |
37 | Cf: |
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 | |
51 | static 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 | |
65 | static 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 | unsigned 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 ((unsigned) 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 != (int) (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 == (int) ((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. nt)*/ |
169 | blockLength = 0; |
170 | goto next; |
171 | } |
172 | if (blockNo != (int) (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 | |
236 | static void sigalrm_handler(int UNUSED_PARAM signum) |
237 | { |
238 | } |
239 | |
240 | int rx_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
241 | int 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 | } |
272 |