1 /* getty.c - A getty program to get controlling terminal.
2 *
3 * Copyright 2012 Sandeep Sharma <sandeep.jack2756@gamil.com>
4 * Copyright 2013 Kyungwan Han <asura321@gmail.com>
5 *
6 * No Standard.
7
8 USE_GETTY(NEWTOY(getty, "<2t#<0H:I:l:f:iwnmLh",TOYFLAG_SBIN))
9
10 config GETTY
11 bool "getty"
12 default n
13 help
14 usage: getty [OPTIONS] BAUD_RATE[,BAUD_RATE]... TTY [TERMTYPE]
15
16 -h Enable hardware RTS/CTS flow control
17 -L Set CLOCAL (ignore Carrier Detect state)
18 -m Get baud rate from modem's CONNECT status message
19 -n Don't prompt for login name
20 -w Wait for CR or LF before sending /etc/issue
21 -i Don't display /etc/issue
22 -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue
23 -l LOGIN Invoke LOGIN instead of /bin/login
24 -t SEC Terminate after SEC if no login name is read
25 -I INITSTR Send INITSTR before anything else
26 -H HOST Log HOST into the utmp file as the hostname
27 */
28 #define FOR_getty
29 #include "toys.h"
30 #include <utmp.h>
31
32 GLOBALS(
33 char *issue_str;
34 char *login_str;
35 char *init_str;
36 char *host_str;
37 long timeout;
38
39 char *tty_name;
40 int speeds[20];
41 int sc;
42 struct termios termios;
43 char buff[128];
44 )
45
46 #define CTL(x) ((x) ^ 0100)
47 #define HOSTNAME_SIZE 32
48
49 typedef void (*sighandler_t)(int);
50 struct speed_mapper {
51 long speed;
52 speed_t code;
53 };
54
55 struct speed_mapper speedtab[] = {
56 {50, B50}, {75, B75}, {110, B110}, {134, B134}, {150, B150}, {200, B200},
57 {300, B300}, {600, B600}, {1200, B1200}, {1800, B1800}, {2400, B2400},
58 {4800, B4800}, {9600, B9600},
59 #ifdef B19200
60 {19200, B19200},
61 #endif
62 #ifdef B38400
63 {38400, B38400},
64 #endif
65 #ifdef EXTA
66 {19200, EXTA},
67 #endif
68 #ifdef EXTB
69 {38400, B38400},
70 #endif
71 #ifdef B57600
72 {57600, B57600},
73 #endif
74 #ifdef B115200
75 {115200, B115200},
76 #endif
77 #ifdef B230400
78 {230400, B230400},
79 #endif
80 {0, 0},
81 };
82
83 // Find speed from mapper array
encode(char * s)84 static speed_t encode(char *s)
85 {
86 struct speed_mapper *sp;
87 long speed = atolx(s);
88
89 if (!speed) return 0;
90 for (sp = speedtab; sp->speed; sp++) if (sp->speed == speed) return sp->code;
91 return (speed_t) -1;
92 }
93
get_speed(char * sp)94 static void get_speed(char *sp)
95 {
96 char *ptr;
97
98 TT.sc = 0;
99 while ((ptr = strsep(&sp, ","))) {
100 TT.speeds[TT.sc] = encode(ptr);
101 if (TT.speeds[TT.sc] < 0) perror_exit("bad speed");
102 if (++TT.sc > 10) perror_exit("too many speeds, max is 10");
103 }
104 }
105
106 // Parse args and set TERM env. variable
parse_arguments(void)107 static void parse_arguments(void)
108 {
109 if (isdigit(**toys.optargs)) {
110 get_speed(*toys.optargs);
111 if (*++toys.optargs) TT.tty_name = xmprintf("%s", *toys.optargs);
112 } else {
113 TT.tty_name = xmprintf("%s", *toys.optargs);
114 if (*++toys.optargs) get_speed(*toys.optargs);
115 }
116 if (*++toys.optargs) setenv("TERM", *toys.optargs, 1);
117 }
118
119 // Get controlling terminal and redirect stdio
open_tty(void)120 static void open_tty(void)
121 {
122 if (strcmp(TT.tty_name, "-")) {
123 if (*(TT.tty_name) != '/') TT.tty_name = xmprintf("/dev/%s", TT.tty_name);
124 // Sends SIGHUP to all foreground process if Session leader don't die,Ignore
125 sighandler_t sig = signal(SIGHUP, SIG_IGN);
126 ioctl(0, TIOCNOTTY, 0); // Giveup if there is any controlling terminal
127 signal(SIGHUP, sig);
128 if ((setsid() < 0) && (getpid() != getsid(0)))
129 perror_exit("setsid");
130 xclose(0);
131 xopen(TT.tty_name, O_RDWR|O_NDELAY|O_CLOEXEC);
132 fcntl(0, F_SETFL, fcntl(0, F_GETFL) & ~O_NONBLOCK); // Block read
133 dup2(0, 1);
134 dup2(0, 2);
135 if (ioctl(0, TIOCSCTTY, 1) < 0) perror_msg("ioctl(TIOCSCTTY)");
136 if (!isatty(0)) perror_exit("/dev/%s: not a tty", TT.tty_name);
137 chown(TT.tty_name, 0, 0); // change ownership, Hope login will change this
138 chmod(TT.tty_name, 0620);
139 } else { // We already have opened TTY
140 if (setsid() < 0) perror_msg("setsid failed");
141 if ((fcntl(0, F_GETFL) & (O_RDWR|O_RDONLY|O_WRONLY)) != O_RDWR)
142 perror_exit("no read/write permission");
143 }
144 }
145
146 // Intialise terminal settings
termios_init(void)147 static void termios_init(void)
148 {
149 if (tcgetattr(STDIN_FILENO, &TT.termios) < 0) perror_exit("tcgetattr");
150 // Flush input and output queues, important for modems!
151 tcflush(STDIN_FILENO, TCIOFLUSH);
152 TT.termios.c_cflag &= (0|CSTOPB|PARENB|PARODD);
153 #ifdef CRTSCTS
154 if (toys.optflags & FLAG_h) TT.termios.c_cflag |= CRTSCTS;
155 #endif
156 if (toys.optflags & FLAG_L) TT.termios.c_cflag |= CLOCAL;
157 TT.termios.c_cc[VTIME] = 0;
158 TT.termios.c_cc[VMIN] = 1;
159 TT.termios.c_oflag = OPOST|ONLCR;
160 TT.termios.c_cflag |= CS8|CREAD|HUPCL|CBAUDEX;
161 // login will disable echo for passwd.
162 TT.termios.c_lflag |= ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOKE;
163 TT.termios.c_cc[VINTR] = CTL('C');
164 TT.termios.c_cc[VQUIT] = CTL('\\');
165 TT.termios.c_cc[VEOF] = CTL('D');
166 TT.termios.c_cc[VEOL] = '\n';
167 TT.termios.c_cc[VKILL] = CTL('U');
168 TT.termios.c_cc[VERASE] = 127; // CERASE
169 TT.termios.c_iflag = ICRNL|IXON|IXOFF;
170 // set non-zero baud rate. Zero baud rate left it unchanged.
171 if (TT.speeds[0] != B0) cfsetspeed(&TT.termios, TT.speeds[0]);
172 if (tcsetattr(STDIN_FILENO, TCSANOW, &TT.termios) < 0)
173 perror_exit("tcsetattr");
174 }
175
176 // Get the baud rate from modems CONNECT mesage, Its of form <junk><BAUD><Junk>
sense_baud(void)177 static void sense_baud(void)
178 {
179 int vmin;
180 ssize_t size;
181 char *ptr;
182 speed_t speed;
183
184 vmin = TT.termios.c_cc[VMIN]; // Store old
185 TT.termios.c_cc[VMIN] = 0; // No block even queue is empty.
186 if (tcsetattr(STDIN_FILENO, TCSANOW, &TT.termios) < 0)
187 perror_exit("tcsetattr");
188 size = readall(STDIN_FILENO, TT.buff, sizeof(TT.buff)-1);
189 if (size > 0) {
190 for (ptr = TT.buff; ptr < TT.buff+size; ptr++) {
191 if (isdigit(*ptr)) {
192 speed = encode(ptr);
193 if (speed > 0) cfsetspeed(&TT.termios,speed);
194 break;
195 }
196 }
197 }
198 TT.termios.c_cc[VMIN] = vmin; //restore old value
199 if (tcsetattr(STDIN_FILENO, TCSANOW, &TT.termios) < 0)
200 perror_exit("tcsetattr");
201 }
202
203 // Just prompt for login name
print_prompt(void)204 void print_prompt(void)
205 {
206 char *hostname;
207 struct utsname uts;
208
209 uname(&uts);
210 hostname = xstrdup(uts.nodename);
211 fputs(hostname, stdout);
212 fputs(" login: ", stdout);
213 fflush(NULL);
214 free(hostname);
215 hostname = NULL;
216 }
217
218 // Print /etc/isuue with taking care of each escape sequence
write_issue(char * file)219 void write_issue(char *file)
220 {
221 char buff[20] = {0,};
222 struct utsname u;
223 uname(&u);
224 int size, fd = open(TT.issue_str, O_RDONLY);
225
226 if (fd < 0) return;
227 while ((size = readall(fd, buff, 1)) > 0) {
228 char *ch = buff;
229
230 if (*ch == '\\' || *ch == '%') {
231 if (readall(fd, buff, 1) <= 0) perror_exit("readall");
232 if (*ch == 's') fputs(u.sysname, stdout);
233 if (*ch == 'n'|| *ch == 'h') fputs(u.nodename, stdout);
234 if (*ch == 'r') fputs(u.release, stdout);
235 if (*ch == 'm') fputs(u.machine, stdout);
236 if (*ch == 'l') fputs(TT.tty_name, stdout);
237 } else xputc(*ch);
238 }
239 }
240
241 // Read login name and print prompt and Issue file.
read_login_name(void)242 static int read_login_name(void)
243 {
244 tcflush(STDIN_FILENO, TCIFLUSH); // Flush pending speed switches
245 int i = 0;
246
247 while (1) { // Option -i will overide -f
248 if (!(toys.optflags & FLAG_i)) write_issue(TT.issue_str);
249 print_prompt();
250 TT.buff[0] = getchar();
251 if (!TT.buff[0] && TT.sc > 1) return 0; // Switch speed
252 if (TT.buff[0] == '\n') continue;
253 if (TT.buff[0] != '\n')
254 if (!fgets(&TT.buff[1], HOSTNAME_SIZE-1, stdin)) _exit(1);
255 while (i < HOSTNAME_SIZE-1 && isgraph(TT.buff[i])) i++;
256 TT.buff[i] = 0;
257 break;
258 }
259 return 1;
260 }
261
262 // Put hostname entry in utmp file
utmp_entry(void)263 static void utmp_entry(void)
264 {
265 struct utmp entry;
266 struct utmp *utp_ptr;
267 pid_t pid = getpid();
268 char *utmperr = "can't make utmp entry, host length greater than UT_HOSTSIZE(256)";
269
270 utmpname(_PATH_UTMP);
271 setutent(); // Starts from start
272 while ((utp_ptr = getutent()))
273 if (utp_ptr->ut_pid == pid && utp_ptr->ut_type >= INIT_PROCESS) break;
274 if (!utp_ptr) {
275 entry.ut_type = LOGIN_PROCESS;
276 entry.ut_pid = getpid();
277 xstrncpy(entry.ut_line, ttyname(STDIN_FILENO) +
278 strlen("/dev/"), UT_LINESIZE);
279 time((time_t *)&entry.ut_time);
280 xstrncpy(entry.ut_user, "LOGIN", UT_NAMESIZE);
281 if (strlen(TT.host_str) > UT_HOSTSIZE)
282 perror_msg(utmperr);
283 else xstrncpy(entry.ut_host, TT.host_str, UT_HOSTSIZE);
284 setutent();
285 pututline(&entry);
286 return;
287 }
288 xstrncpy(entry.ut_line, ttyname(STDIN_FILENO) + strlen("/dev/"), UT_LINESIZE);
289 xstrncpy(entry.ut_user, "LOGIN", UT_NAMESIZE);
290 if (strlen(TT.host_str) > UT_HOSTSIZE)
291 perror_msg(utmperr);
292 else xstrncpy(entry.ut_host, TT.host_str, UT_HOSTSIZE);
293 time((time_t *)&entry.ut_time);
294 setutent();
295 pututline(&entry);
296 }
297
getty_main(void)298 void getty_main(void)
299 {
300 pid_t pid = getpid();
301 char *ptr[3] = {"/bin/login", NULL, NULL}; //2 NULLs so we can add username
302
303 if (!(toys.optflags & FLAG_f)) TT.issue_str = "/etc/issue";
304 if (toys.optflags & FLAG_l) ptr[0] = TT.login_str;
305 parse_arguments();
306 open_tty();
307 termios_init();
308 tcsetpgrp(STDIN_FILENO, pid);
309 if (toys.optflags & FLAG_H) utmp_entry();
310 if (toys.optflags & FLAG_I)
311 writeall(STDOUT_FILENO,TT.init_str,strlen(TT.init_str));
312 if (toys.optflags & FLAG_m) sense_baud();
313 if (toys.optflags & FLAG_t) alarm(TT.timeout);
314 if (toys.optflags & FLAG_w) {
315 char ch;
316
317 while (readall(STDIN_FILENO, &ch, 1) != 1)
318 if (ch == '\n' || ch == '\r') break;
319 }
320 if (!(toys.optflags & FLAG_n)) {
321 int index = 1; // 0th we already set.
322
323 while (1) {
324 int l = read_login_name();
325
326 if (l) break;
327 index = index % TT.sc;
328 cfsetspeed(&TT.termios, TT.speeds[index]); // Select from multiple speeds
329 //Necessary after cfsetspeed
330 if (tcsetattr(STDIN_FILENO, TCSANOW, &TT.termios) < 0)
331 perror_exit("tcsetattr");
332 }
333 ptr[1]=TT.buff; //put the username in the login command line
334 }
335 xexec(ptr);
336 }
337