source: branches/3.2/mindi-busybox/miscutils/microcom.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
  • Property svn:eol-style set to native
File size: 4.6 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * bare bones 'talk to modem' program - similar to 'cu -l $device'
4 * inspired by mgetty's microcom
5 *
6 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
7 *
8 * Licensed under GPLv2, see file LICENSE in this source tree.
9 */
10
11//usage:#define microcom_trivial_usage
12//usage:       "[-d DELAY] [-t TIMEOUT] [-s SPEED] [-X] TTY"
13//usage:#define microcom_full_usage "\n\n"
14//usage:       "Copy bytes for stdin to TTY and from TTY to stdout\n"
15//usage:     "\n    -d  Wait up to DELAY ms for TTY output before sending every"
16//usage:     "\n        next byte to it"
17//usage:     "\n    -t  Exit if both stdin and TTY are silent for TIMEOUT ms"
18//usage:     "\n    -s  Set serial line to SPEED"
19//usage:     "\n    -X  Disable special meaning of NUL and Ctrl-X from stdin"
20
21#include "libbb.h"
22
23// set raw tty mode
24static void xget1(int fd, struct termios *t, struct termios *oldt)
25{
26    tcgetattr(fd, oldt);
27    *t = *oldt;
28    cfmakeraw(t);
29//  t->c_lflag &= ~(ISIG|ICANON|ECHO|IEXTEN);
30//  t->c_iflag &= ~(BRKINT|IXON|ICRNL);
31//  t->c_oflag &= ~(ONLCR);
32//  t->c_cc[VMIN]  = 1;
33//  t->c_cc[VTIME] = 0;
34}
35
36static int xset1(int fd, struct termios *tio, const char *device)
37{
38    int ret = tcsetattr(fd, TCSAFLUSH, tio);
39
40    if (ret) {
41        bb_perror_msg("can't tcsetattr for %s", device);
42    }
43    return ret;
44}
45
46int microcom_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
47int microcom_main(int argc UNUSED_PARAM, char **argv)
48{
49    int sfd;
50    int nfd;
51    struct pollfd pfd[2];
52    struct termios tio0, tiosfd, tio;
53    char *device_lock_file;
54    enum {
55        OPT_X = 1 << 0, // do not respect Ctrl-X, Ctrl-@
56        OPT_s = 1 << 1, // baudrate
57        OPT_d = 1 << 2, // wait for device response, ms
58        OPT_t = 1 << 3, // timeout, ms
59    };
60    speed_t speed = 9600;
61    int delay = -1;
62    int timeout = -1;
63    unsigned opts;
64
65    // fetch options
66    opt_complementary = "=1:s+:d+:t+"; // exactly one arg, numeric options
67    opts = getopt32(argv, "Xs:d:t:", &speed, &delay, &timeout);
68//  argc -= optind;
69    argv += optind;
70
71    // try to create lock file in /var/lock
72    device_lock_file = (char *)bb_basename(argv[0]);
73    device_lock_file = xasprintf("/var/lock/LCK..%s", device_lock_file);
74    sfd = open(device_lock_file, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
75    if (sfd < 0) {
76        // device already locked -> bail out
77        if (errno == EEXIST)
78            bb_perror_msg_and_die("can't create '%s'", device_lock_file);
79        // can't create lock -> don't care
80        if (ENABLE_FEATURE_CLEAN_UP)
81            free(device_lock_file);
82        device_lock_file = NULL;
83    } else {
84        // %4d to make concurrent mgetty (if any) happy.
85        // Mgetty treats 4-bytes lock files as binary,
86        // not text, PID. Making 5+ char file. Brrr...
87        fdprintf(sfd, "%4d\n", getpid());
88        close(sfd);
89    }
90
91    // setup signals
92    bb_signals(0
93        + (1 << SIGHUP)
94        + (1 << SIGINT)
95        + (1 << SIGTERM)
96        + (1 << SIGPIPE)
97        , record_signo);
98
99    // error exit code if we fail to open the device
100    bb_got_signal = 1;
101
102    // open device
103    sfd = open_or_warn(argv[0], O_RDWR | O_NOCTTY | O_NONBLOCK);
104    if (sfd < 0)
105        goto done;
106    fcntl(sfd, F_SETFL, O_RDWR);
107
108    // put device to "raw mode"
109    xget1(sfd, &tio, &tiosfd);
110    // set device speed
111    cfsetspeed(&tio, tty_value_to_baud(speed));
112    if (xset1(sfd, &tio, argv[0]))
113        goto done;
114
115    // put stdin to "raw mode" (if stdin is a TTY),
116    // handle one character at a time
117    if (isatty(STDIN_FILENO)) {
118        xget1(STDIN_FILENO, &tio, &tio0);
119        if (xset1(STDIN_FILENO, &tio, "stdin"))
120            goto done;
121    }
122
123    // main loop: check with poll(), then read/write bytes across
124    pfd[0].fd = sfd;
125    pfd[0].events = POLLIN;
126    pfd[1].fd = STDIN_FILENO;
127    pfd[1].events = POLLIN;
128
129    bb_got_signal = 0;
130    nfd = 2;
131    // Not safe_poll: we want to exit on signal
132    while (!bb_got_signal && poll(pfd, nfd, timeout) > 0) {
133        if (nfd > 1 && pfd[1].revents) {
134            char c;
135            // read from stdin -> write to device
136            if (safe_read(STDIN_FILENO, &c, 1) < 1) {
137                // don't poll stdin anymore if we got EOF/error
138                nfd--;
139                goto skip_write;
140            }
141            // do we need special processing?
142            if (!(opts & OPT_X)) {
143                // ^@ sends Break
144                if (VINTR == c) {
145                    tcsendbreak(sfd, 0);
146                    goto skip_write;
147                }
148                // ^X exits
149                if (24 == c)
150                    break;
151            }
152            write(sfd, &c, 1);
153            if (delay >= 0)
154                safe_poll(pfd, 1, delay);
155skip_write: ;
156        }
157        if (pfd[0].revents) {
158#define iobuf bb_common_bufsiz1
159            ssize_t len;
160            // read from device -> write to stdout
161            len = safe_read(sfd, iobuf, sizeof(iobuf));
162            if (len > 0)
163                full_write(STDOUT_FILENO, iobuf, len);
164            else {
165                // EOF/error -> bail out
166                bb_got_signal = SIGHUP;
167                break;
168            }
169        }
170    }
171
172    // restore device mode
173    tcsetattr(sfd, TCSAFLUSH, &tiosfd);
174
175    if (isatty(STDIN_FILENO))
176        tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
177
178done:
179    if (device_lock_file)
180        unlink(device_lock_file);
181
182    return bb_got_signal;
183}
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