| /* vi: set sw=4 ts=4: */ |
| /*------------------------------------------------------------------------- |
| * Filename: xmodem.c |
| * Copyright: Copyright (C) 2001, Hewlett-Packard Company |
| * Author: Christopher Hoover <ch@hpl.hp.com> |
| * Description: xmodem functionality for uploading of kernels |
| * and the like |
| * Created at: Thu Dec 20 01:58:08 PST 2001 |
| *-----------------------------------------------------------------------*/ |
| /* |
| * xmodem.c: xmodem functionality for uploading of kernels and |
| * the like |
| * |
| * Copyright (C) 2001 Hewlett-Packard Laboratories |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
| * |
| * This was originally written for blob and then adapted for busybox. |
| * |
| */ |
| |
| #include "libbb.h" |
| |
| #define SOH 0x01 |
| #define STX 0x02 |
| #define EOT 0x04 |
| #define ACK 0x06 |
| #define NAK 0x15 |
| #define BS 0x08 |
| |
| /* |
| |
| Cf: |
| |
| http://www.textfiles.com/apple/xmodem |
| http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt |
| http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt |
| http://www.phys.washington.edu/~belonis/xmodem/modmprot.col |
| |
| */ |
| |
| #define TIMEOUT 1 |
| #define TIMEOUT_LONG 10 |
| #define MAXERRORS 10 |
| |
| static int read_byte(int fd, unsigned timeout) |
| { |
| char buf[1]; |
| int n; |
| |
| alarm(timeout); |
| |
| n = read(fd, &buf, 1); |
| |
| alarm(0); |
| |
| if (n == 1) |
| return buf[0] & 0xff; |
| else |
| return -1; |
| } |
| |
| static int receive(char *error_buf, size_t error_buf_size, |
| int ttyfd, int filefd) |
| { |
| char blockBuf[1024]; |
| unsigned int errors = 0; |
| unsigned int wantBlockNo = 1; |
| unsigned int length = 0; |
| int docrc = 1; |
| char nak = 'C'; |
| unsigned int timeout = TIMEOUT_LONG; |
| |
| #define note_error(fmt,args...) \ |
| snprintf(error_buf, error_buf_size, fmt,##args) |
| |
| /* Flush pending input */ |
| tcflush(ttyfd, TCIFLUSH); |
| |
| /* Ask for CRC; if we get errors, we will go with checksum */ |
| write(ttyfd, &nak, 1); |
| |
| for (;;) { |
| int blockBegin; |
| int blockNo, blockNoOnesCompl; |
| int blockLength; |
| int cksum = 0; |
| int crcHi = 0; |
| int crcLo = 0; |
| |
| blockBegin = read_byte(ttyfd, timeout); |
| if (blockBegin < 0) |
| goto timeout; |
| |
| timeout = TIMEOUT; |
| nak = NAK; |
| |
| switch (blockBegin) { |
| case SOH: |
| case STX: |
| break; |
| |
| case EOT: |
| nak = ACK; |
| write(ttyfd, &nak, 1); |
| goto done; |
| |
| default: |
| goto error; |
| } |
| |
| /* block no */ |
| blockNo = read_byte(ttyfd, TIMEOUT); |
| if (blockNo < 0) |
| goto timeout; |
| |
| /* block no one's compliment */ |
| blockNoOnesCompl = read_byte(ttyfd, TIMEOUT); |
| if (blockNoOnesCompl < 0) |
| goto timeout; |
| |
| if (blockNo != (255 - blockNoOnesCompl)) { |
| note_error("bad block ones compl"); |
| goto error; |
| } |
| |
| blockLength = (blockBegin == SOH) ? 128 : 1024; |
| |
| { |
| int i; |
| |
| for (i = 0; i < blockLength; i++) { |
| int cc = read_byte(ttyfd, TIMEOUT); |
| if (cc < 0) |
| goto timeout; |
| blockBuf[i] = cc; |
| } |
| } |
| |
| if (docrc) { |
| crcHi = read_byte(ttyfd, TIMEOUT); |
| if (crcHi < 0) |
| goto timeout; |
| |
| crcLo = read_byte(ttyfd, TIMEOUT); |
| if (crcLo < 0) |
| goto timeout; |
| } else { |
| cksum = read_byte(ttyfd, TIMEOUT); |
| if (cksum < 0) |
| goto timeout; |
| } |
| |
| if (blockNo == ((wantBlockNo - 1) & 0xff)) { |
| /* a repeat of the last block is ok, just ignore it. */ |
| /* this also ignores the initial block 0 which is */ |
| /* meta data. */ |
| goto next; |
| } else if (blockNo != (wantBlockNo & 0xff)) { |
| note_error("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo); |
| goto error; |
| } |
| |
| if (docrc) { |
| int crc = 0; |
| int i, j; |
| int expectedCrcHi; |
| int expectedCrcLo; |
| |
| for (i = 0; i < blockLength; i++) { |
| crc = crc ^ (int) blockBuf[i] << 8; |
| for (j = 0; j < 8; j++) |
| if (crc & 0x8000) |
| crc = crc << 1 ^ 0x1021; |
| else |
| crc = crc << 1; |
| } |
| |
| expectedCrcHi = (crc >> 8) & 0xff; |
| expectedCrcLo = crc & 0xff; |
| |
| if ((crcHi != expectedCrcHi) || |
| (crcLo != expectedCrcLo)) { |
| note_error("crc error, expected 0x%02x 0x%02x, got 0x%02x 0x%02x", expectedCrcHi, expectedCrcLo, crcHi, crcLo); |
| goto error; |
| } |
| } else { |
| unsigned char expectedCksum = 0; |
| int i; |
| |
| for (i = 0; i < blockLength; i++) |
| expectedCksum += blockBuf[i]; |
| |
| if (cksum != expectedCksum) { |
| note_error("checksum error, expected 0x%02x, got 0x%02x", expectedCksum, cksum); |
| goto error; |
| } |
| } |
| |
| wantBlockNo++; |
| length += blockLength; |
| |
| if (full_write(filefd, blockBuf, blockLength) < 0) { |
| note_error("write to file failed: %m"); |
| goto fatal; |
| } |
| |
| next: |
| errors = 0; |
| nak = ACK; |
| write(ttyfd, &nak, 1); |
| continue; |
| |
| error: |
| timeout: |
| errors++; |
| if (errors == MAXERRORS) { |
| /* Abort */ |
| |
| // if using crc, try again w/o crc |
| if (nak == 'C') { |
| nak = NAK; |
| errors = 0; |
| docrc = 0; |
| goto timeout; |
| } |
| |
| note_error("too many errors; giving up"); |
| |
| fatal: |
| /* 5 CAN followed by 5 BS */ |
| write(ttyfd, "\030\030\030\030\030\010\010\010\010\010", 10); |
| return -1; |
| } |
| |
| /* Flush pending input */ |
| tcflush(ttyfd, TCIFLUSH); |
| |
| write(ttyfd, &nak, 1); |
| } |
| |
| done: |
| return length; |
| |
| #undef note_error |
| } |
| |
| static void sigalrm_handler(int ATTRIBUTE_UNUSED signum) |
| { |
| } |
| |
| int rx_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int rx_main(int argc, char **argv) |
| { |
| char *fn; |
| int ttyfd, filefd; |
| struct termios tty, orig_tty; |
| struct sigaction act; |
| int n; |
| char error_buf[256]; |
| |
| if (argc != 2) |
| bb_show_usage(); |
| |
| fn = argv[1]; |
| ttyfd = xopen(CURRENT_TTY, O_RDWR); |
| filefd = xopen(fn, O_RDWR|O_CREAT|O_TRUNC); |
| |
| if (tcgetattr(ttyfd, &tty) < 0) |
| bb_perror_msg_and_die("tcgetattr"); |
| |
| orig_tty = tty; |
| |
| cfmakeraw(&tty); |
| tcsetattr(ttyfd, TCSAFLUSH, &tty); |
| |
| memset(&act, 0, sizeof(act)); |
| act.sa_handler = sigalrm_handler; |
| sigaction(SIGALRM, &act, 0); |
| |
| n = receive(error_buf, sizeof(error_buf), ttyfd, filefd); |
| |
| close(filefd); |
| |
| tcsetattr(ttyfd, TCSAFLUSH, &orig_tty); |
| |
| if (n < 0) |
| bb_error_msg_and_die("\nreceive failed:\n %s", error_buf); |
| |
| fflush_stdout_and_exit(EXIT_SUCCESS); |
| } |