source: branches/3.2/mindi-busybox/networking/slattach.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: 6.1 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Stripped down version of net-tools for busybox.
4 *
5 * Author: Ignacio Garcia Perez (iggarpe at gmail dot com)
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 *
9 * There are some differences from the standard net-tools slattach:
10 *
11 * - The -l option is not supported.
12 *
13 * - The -F options allows disabling of RTS/CTS flow control.
14 */
15
16//usage:#define slattach_trivial_usage
17//usage:       "[-cehmLF] [-s SPEED] [-p PROTOCOL] DEVICE"
18//usage:#define slattach_full_usage "\n\n"
19//usage:       "Attach network interface(s) to serial line(s)\n"
20//usage:     "\n    -p PROT Set protocol (slip, cslip, slip6, clisp6 or adaptive)"
21//usage:     "\n    -s SPD  Set line speed"
22//usage:     "\n    -e  Exit after initializing device"
23//usage:     "\n    -h  Exit when the carrier is lost"
24//usage:     "\n    -c PROG Run PROG when the line is hung up"
25//usage:     "\n    -m  Do NOT initialize the line in raw 8 bits mode"
26//usage:     "\n    -L  Enable 3-wire operation"
27//usage:     "\n    -F  Disable RTS/CTS flow control"
28
29#include "libbb.h"
30#include "libiproute/utils.h" /* invarg() */
31
32struct globals {
33    int handle;
34    int saved_disc;
35    struct termios saved_state;
36} FIX_ALIASING;
37#define G (*(struct globals*)&bb_common_bufsiz1)
38#define handle       (G.handle      )
39#define saved_disc   (G.saved_disc  )
40#define saved_state  (G.saved_state )
41#define INIT_G() do { } while (0)
42
43
44/*
45 * Save tty state and line discipline
46 *
47 * It is fine here to bail out on errors, since we haven modified anything yet
48 */
49static void save_state(void)
50{
51    /* Save line status */
52    if (tcgetattr(handle, &saved_state) < 0)
53        bb_perror_msg_and_die("get state");
54
55    /* Save line discipline */
56    xioctl(handle, TIOCGETD, &saved_disc);
57}
58
59static int set_termios_state_or_warn(struct termios *state)
60{
61    int ret;
62
63    ret = tcsetattr(handle, TCSANOW, state);
64    if (ret < 0) {
65        bb_perror_msg("set state");
66        return 1; /* used as exitcode */
67    }
68    return 0;
69}
70
71/*
72 * Restore state and line discipline for ALL managed ttys
73 *
74 * Restoring ALL managed ttys is the only way to have a single
75 * hangup delay.
76 *
77 * Go on after errors: we want to restore as many controlled ttys
78 * as possible.
79 */
80static void restore_state_and_exit(int exitcode) NORETURN;
81static void restore_state_and_exit(int exitcode)
82{
83    struct termios state;
84
85    /* Restore line discipline */
86    if (ioctl_or_warn(handle, TIOCSETD, &saved_disc) < 0) {
87        exitcode = 1;
88    }
89
90    /* Hangup */
91    memcpy(&state, &saved_state, sizeof(state));
92    cfsetispeed(&state, B0);
93    cfsetospeed(&state, B0);
94    if (set_termios_state_or_warn(&state))
95        exitcode = 1;
96    sleep(1);
97
98    /* Restore line status */
99    if (set_termios_state_or_warn(&saved_state))
100        exit(EXIT_FAILURE);
101    if (ENABLE_FEATURE_CLEAN_UP)
102        close(handle);
103
104    exit(exitcode);
105}
106
107/*
108 * Set tty state, line discipline and encapsulation
109 */
110static void set_state(struct termios *state, int encap)
111{
112    int disc;
113
114    /* Set line status */
115    if (set_termios_state_or_warn(state))
116        goto bad;
117    /* Set line discliple (N_SLIP always) */
118    disc = N_SLIP;
119    if (ioctl_or_warn(handle, TIOCSETD, &disc) < 0) {
120        goto bad;
121    }
122
123    /* Set encapsulation (SLIP, CSLIP, etc) */
124    if (ioctl_or_warn(handle, SIOCSIFENCAP, &encap) < 0) {
125 bad:
126        restore_state_and_exit(EXIT_FAILURE);
127    }
128}
129
130static void sig_handler(int signo UNUSED_PARAM)
131{
132    restore_state_and_exit(EXIT_SUCCESS);
133}
134
135int slattach_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
136int slattach_main(int argc UNUSED_PARAM, char **argv)
137{
138    /* Line discipline code table */
139    static const char proto_names[] ALIGN1 =
140        "slip\0"        /* 0 */
141        "cslip\0"       /* 1 */
142        "slip6\0"       /* 2 */
143        "cslip6\0"      /* 3 */
144        "adaptive\0"    /* 8 */
145        ;
146
147    int i, encap, opt;
148    struct termios state;
149    const char *proto = "cslip";
150    const char *extcmd;   /* Command to execute after hangup */
151    const char *baud_str;
152    int baud_code = -1;   /* Line baud rate (system code) */
153
154    enum {
155        OPT_p_proto  = 1 << 0,
156        OPT_s_baud   = 1 << 1,
157        OPT_c_extcmd = 1 << 2,
158        OPT_e_quit   = 1 << 3,
159        OPT_h_watch  = 1 << 4,
160        OPT_m_nonraw = 1 << 5,
161        OPT_L_local  = 1 << 6,
162        OPT_F_noflow = 1 << 7
163    };
164
165    INIT_G();
166
167    /* Parse command line options */
168    opt = getopt32(argv, "p:s:c:ehmLF", &proto, &baud_str, &extcmd);
169    /*argc -= optind;*/
170    argv += optind;
171
172    if (!*argv)
173        bb_show_usage();
174
175    encap = index_in_strings(proto_names, proto);
176
177    if (encap < 0)
178        invarg(proto, "protocol");
179    if (encap > 3)
180        encap = 8;
181
182    /* We want to know if the baud rate is valid before we start touching the ttys */
183    if (opt & OPT_s_baud) {
184        baud_code = tty_value_to_baud(xatoi(baud_str));
185        if (baud_code < 0)
186            invarg(baud_str, "baud rate");
187    }
188
189    /* Trap signals in order to restore tty states upon exit */
190    if (!(opt & OPT_e_quit)) {
191        bb_signals(0
192            + (1 << SIGHUP)
193            + (1 << SIGINT)
194            + (1 << SIGQUIT)
195            + (1 << SIGTERM)
196            , sig_handler);
197    }
198
199    /* Open tty */
200    handle = open(*argv, O_RDWR | O_NDELAY);
201    if (handle < 0) {
202        char *buf = concat_path_file("/dev", *argv);
203        handle = xopen(buf, O_RDWR | O_NDELAY);
204        /* maybe if (ENABLE_FEATURE_CLEAN_UP) ?? */
205        free(buf);
206    }
207
208    /* Save current tty state */
209    save_state();
210
211    /* Configure tty */
212    memcpy(&state, &saved_state, sizeof(state));
213    if (!(opt & OPT_m_nonraw)) { /* raw not suppressed */
214        memset(&state.c_cc, 0, sizeof(state.c_cc));
215        state.c_cc[VMIN] = 1;
216        state.c_iflag = IGNBRK | IGNPAR;
217        state.c_oflag = 0;
218        state.c_lflag = 0;
219        state.c_cflag = CS8 | HUPCL | CREAD
220                      | ((opt & OPT_L_local) ? CLOCAL : 0)
221                      | ((opt & OPT_F_noflow) ? 0 : CRTSCTS);
222        cfsetispeed(&state, cfgetispeed(&saved_state));
223        cfsetospeed(&state, cfgetospeed(&saved_state));
224    }
225
226    if (opt & OPT_s_baud) {
227        cfsetispeed(&state, baud_code);
228        cfsetospeed(&state, baud_code);
229    }
230
231    set_state(&state, encap);
232
233    /* Exit now if option -e was passed */
234    if (opt & OPT_e_quit)
235        return 0;
236
237    /* If we're not requested to watch, just keep descriptor open
238     * until we are killed */
239    if (!(opt & OPT_h_watch))
240        while (1)
241            sleep(24*60*60);
242
243    /* Watch line for hangup */
244    while (1) {
245        if (ioctl(handle, TIOCMGET, &i) < 0 || !(i & TIOCM_CAR))
246            goto no_carrier;
247        sleep(15);
248    }
249
250 no_carrier:
251
252    /* Execute command on hangup */
253    if (opt & OPT_c_extcmd)
254        system(extcmd);
255
256    /* Restore states and exit */
257    restore_state_and_exit(EXIT_SUCCESS);
258}
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