blob: a500da6d061735df93f2a1bf337563c687d0034b
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 | |
32 | struct 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 | */ |
49 | static 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 | |
59 | static 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 | */ |
80 | static void restore_state_and_exit(int exitcode) NORETURN; |
81 | static 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 | */ |
110 | static 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 | |
130 | static void sig_handler(int signo UNUSED_PARAM) |
131 | { |
132 | restore_state_and_exit(EXIT_SUCCESS); |
133 | } |
134 | |
135 | int slattach_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
136 | int 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 | } |
259 |