| /* vi: set sw=4 ts=4: */ |
| /* |
| * 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 functionality for uploading of kernels and the like |
| * |
| * Copyright (C) 2001 Hewlett-Packard Laboratories |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| * |
| * This was originally written for blob and then adapted for busybox. |
| */ |
| //config:config RX |
| //config: bool "rx (2.9 kb)" |
| //config: default y |
| //config: help |
| //config: Receive files using the Xmodem protocol. |
| |
| //applet:IF_RX(APPLET(rx, BB_DIR_USR_BIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_RX) += rx.o |
| |
| //usage:#define rx_trivial_usage |
| //usage: "FILE" |
| //usage:#define rx_full_usage "\n\n" |
| //usage: "Receive a file using the xmodem protocol" |
| //usage: |
| //usage:#define rx_example_usage |
| //usage: "$ rx /tmp/foo\n" |
| |
| #include "libbb.h" |
| |
| #define SOH 0x01 |
| #define STX 0x02 |
| #define EOT 0x04 |
| #define ACK 0x06 |
| #define NAK 0x15 |
| #define BS 0x08 |
| #define PAD 0x1A |
| |
| /* |
| 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 |
| |
| #define read_fd STDIN_FILENO |
| #define write_fd STDOUT_FILENO |
| |
| static int read_byte(unsigned timeout) |
| { |
| unsigned char buf; |
| int n; |
| |
| alarm(timeout); |
| /* NOT safe_read! We want ALRM to interrupt us */ |
| n = read(read_fd, &buf, 1); |
| alarm(0); |
| if (n == 1) |
| return buf; |
| return -1; |
| } |
| |
| static int receive(/*int read_fd, */int file_fd) |
| { |
| unsigned char blockBuf[1024]; |
| unsigned blockLength = 0; |
| unsigned errors = 0; |
| unsigned wantBlockNo = 1; |
| unsigned length = 0; |
| int do_crc = 1; |
| char reply_char; |
| unsigned timeout = TIMEOUT_LONG; |
| |
| /* Flush pending input */ |
| tcflush(read_fd, TCIFLUSH); |
| |
| /* Ask for CRC; if we get errors, we will go with checksum */ |
| reply_char = 'C'; |
| full_write(write_fd, &reply_char, 1); |
| |
| for (;;) { |
| int blockBegin; |
| int blockNo, blockNoOnesCompl; |
| int cksum_or_crc; |
| unsigned expected; |
| int i, j; |
| |
| blockBegin = read_byte(timeout); |
| if (blockBegin < 0) |
| goto timeout; |
| |
| /* If last block, remove padding */ |
| if (blockBegin == EOT) { |
| /* Data blocks can be padded with ^Z characters */ |
| /* This code tries to detect and remove them */ |
| if (blockLength >= 3 |
| && blockBuf[blockLength - 1] == PAD |
| && blockBuf[blockLength - 2] == PAD |
| && blockBuf[blockLength - 3] == PAD |
| ) { |
| while (blockLength |
| && blockBuf[blockLength - 1] == PAD |
| ) { |
| blockLength--; |
| } |
| } |
| } |
| /* Write previously received block */ |
| errno = 0; |
| if (full_write(file_fd, blockBuf, blockLength) != blockLength) { |
| bb_simple_perror_msg(bb_msg_write_error); |
| goto fatal; |
| } |
| |
| timeout = TIMEOUT; |
| reply_char = NAK; |
| |
| switch (blockBegin) { |
| case SOH: |
| case STX: |
| break; |
| case EOT: |
| reply_char = ACK; |
| full_write(write_fd, &reply_char, 1); |
| return length; |
| default: |
| goto error; |
| } |
| |
| /* Block no */ |
| blockNo = read_byte(TIMEOUT); |
| if (blockNo < 0) |
| goto timeout; |
| |
| /* Block no, in one's complement form */ |
| blockNoOnesCompl = read_byte(TIMEOUT); |
| if (blockNoOnesCompl < 0) |
| goto timeout; |
| |
| if (blockNo != (255 - blockNoOnesCompl)) { |
| bb_simple_error_msg("bad block ones compl"); |
| goto error; |
| } |
| |
| blockLength = (blockBegin == SOH) ? 128 : 1024; |
| |
| for (i = 0; i < blockLength; i++) { |
| int cc = read_byte(TIMEOUT); |
| if (cc < 0) |
| goto timeout; |
| blockBuf[i] = cc; |
| } |
| |
| cksum_or_crc = read_byte(TIMEOUT); |
| if (cksum_or_crc < 0) |
| goto timeout; |
| if (do_crc) { |
| cksum_or_crc = (cksum_or_crc << 8) | read_byte(TIMEOUT); |
| if (cksum_or_crc < 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. */ |
| blockLength = 0; |
| goto next; |
| } |
| if (blockNo != (wantBlockNo & 0xff)) { |
| bb_error_msg("unexpected block no, 0x%08x, expecting 0x%08x", blockNo, wantBlockNo); |
| goto error; |
| } |
| |
| expected = 0; |
| if (do_crc) { |
| for (i = 0; i < blockLength; i++) { |
| expected = expected ^ blockBuf[i] << 8; |
| for (j = 0; j < 8; j++) { |
| if (expected & 0x8000) |
| expected = (expected << 1) ^ 0x1021; |
| else |
| expected = (expected << 1); |
| } |
| } |
| expected &= 0xffff; |
| } else { |
| for (i = 0; i < blockLength; i++) |
| expected += blockBuf[i]; |
| expected &= 0xff; |
| } |
| if (cksum_or_crc != expected) { |
| bb_error_msg(do_crc ? "crc error, expected 0x%04x, got 0x%04x" |
| : "checksum error, expected 0x%02x, got 0x%02x", |
| expected, cksum_or_crc); |
| goto error; |
| } |
| |
| wantBlockNo++; |
| length += blockLength; |
| next: |
| errors = 0; |
| reply_char = ACK; |
| full_write(write_fd, &reply_char, 1); |
| continue; |
| error: |
| timeout: |
| blockLength = 0; |
| errors++; |
| if (errors == MAXERRORS) { |
| /* Abort */ |
| |
| /* If were asking for crc, try again w/o crc */ |
| if (reply_char == 'C') { |
| reply_char = NAK; |
| errors = 0; |
| do_crc = 0; |
| goto timeout; |
| } |
| bb_simple_error_msg("too many errors; giving up"); |
| fatal: |
| /* 5 CAN followed by 5 BS. Don't try too hard... */ |
| safe_write(write_fd, "\030\030\030\030\030\010\010\010\010\010", 10); |
| return -1; |
| } |
| |
| /* Flush pending input */ |
| tcflush(read_fd, TCIFLUSH); |
| |
| full_write(write_fd, &reply_char, 1); |
| } /* for (;;) */ |
| } |
| |
| static void sigalrm_handler(int UNUSED_PARAM signum) |
| { |
| } |
| |
| int rx_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int rx_main(int argc UNUSED_PARAM, char **argv) |
| { |
| struct termios tty, orig_tty; |
| int termios_err; |
| int file_fd; |
| int n; |
| |
| /* Disabled by vda: |
| * why we can't receive from stdin? Why we *require* |
| * controlling tty?? */ |
| /*read_fd = xopen(CURRENT_TTY, O_RDWR);*/ |
| file_fd = xopen(single_argv(argv), O_RDWR|O_CREAT|O_TRUNC); |
| |
| termios_err = tcgetattr(read_fd, &tty); |
| if (termios_err == 0) { |
| //TODO: use set_termios_to_raw() |
| orig_tty = tty; |
| cfmakeraw(&tty); |
| tcsetattr(read_fd, TCSAFLUSH, &tty); |
| } |
| |
| /* No SA_RESTART: we want ALRM to interrupt read() */ |
| signal_no_SA_RESTART_empty_mask(SIGALRM, sigalrm_handler); |
| |
| n = receive(file_fd); |
| |
| if (termios_err == 0) |
| tcsetattr(read_fd, TCSAFLUSH, &orig_tty); |
| if (ENABLE_FEATURE_CLEAN_UP) |
| close(file_fd); |
| fflush_stdout_and_exit(n >= 0); |
| } |