1 /* getty.c - A getty program to get controlling terminal.
2 *
3 * Copyright 2012 Sandeep Sharma <[email protected]>
4 * Copyright 2013 Kyungwan Han <[email protected]>
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 Wait for a modem to dial into serial port, adjust baud rate, call login.
17
18 -h Enable hardware RTS/CTS flow control
19 -L Set CLOCAL (ignore Carrier Detect state)
20 -m Get baud rate from modem's CONNECT status message
21 -n Don't prompt for login name
22 -w Wait for CR or LF before sending /etc/issue
23 -i Don't display /etc/issue
24 -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue
25 -l LOGIN Invoke LOGIN instead of /bin/login
26 -t SEC Terminate after SEC if no login name is read
27 -I INITSTR Send INITSTR before anything else
28 -H HOST Log HOST into the utmp file as the hostname
29 */
30
31 #define FOR_getty
32 #include "toys.h"
33
34 GLOBALS(
35 char *f, *l, *I, *H;
36 long t;
37
38 char *tty_name, buff[128];
39 int speeds[20], sc;
40 struct termios termios;
41 struct utsname uts;
42 )
43
44 #define CTL(x) ((x) ^ 0100)
45 #define HOSTNAME_SIZE 32
46
parse_speeds(char * sp)47 static void parse_speeds(char *sp)
48 {
49 char *ptr;
50
51 TT.sc = 0;
52 while ((ptr = strsep(&sp, ","))) {
53 TT.speeds[TT.sc] = atolx_range(ptr, 0, INT_MAX);
54 if (TT.speeds[TT.sc] < 0) perror_exit("bad speed %s", ptr);
55 if (++TT.sc > 10) perror_exit("too many speeds, max is 10");
56 }
57 }
58
59 // Get controlling terminal and redirect stdio
open_tty(void)60 static void open_tty(void)
61 {
62 if (strcmp(TT.tty_name, "-")) {
63 if (*(TT.tty_name) != '/') TT.tty_name = xmprintf("/dev/%s", TT.tty_name);
64 // Sends SIGHUP to all foreground process if Session leader don't die,Ignore
65 void* handler = signal(SIGHUP, SIG_IGN);
66 ioctl(0, TIOCNOTTY, 0); // Giveup if there is any controlling terminal
67 signal(SIGHUP, handler);
68 if ((setsid() < 0) && (getpid() != getsid(0))) perror_exit("setsid");
69 xclose(0);
70 xopen_stdio(TT.tty_name, O_RDWR|O_NDELAY|O_CLOEXEC);
71 fcntl(0, F_SETFL, fcntl(0, F_GETFL) & ~O_NONBLOCK); // Block read
72 dup2(0, 1);
73 dup2(0, 2);
74 if (ioctl(0, TIOCSCTTY, 1) < 0) perror_msg("ioctl(TIOCSCTTY)");
75 if (!isatty(0)) perror_exit("/dev/%s: not a tty", TT.tty_name);
76 chown(TT.tty_name, 0, 0); // change ownership, Hope login will change this
77 chmod(TT.tty_name, 0620);
78 } else { // We already have opened TTY
79 if (setsid() < 0) perror_msg("setsid failed");
80 if ((fcntl(0, F_GETFL) & (O_RDWR|O_RDONLY|O_WRONLY)) != O_RDWR)
81 perror_exit("no read/write permission");
82 }
83 }
84
termios_init(void)85 static void termios_init(void)
86 {
87 if (tcgetattr(0, &TT.termios) < 0) perror_exit("tcgetattr");
88 // Flush input and output queues, important for modems!
89 tcflush(0, TCIOFLUSH);
90 TT.termios.c_cflag &= (0|CSTOPB|PARENB|PARODD);
91 #ifdef CRTSCTS
92 if (FLAG(h)) TT.termios.c_cflag |= CRTSCTS;
93 #endif
94 if (FLAG(L)) TT.termios.c_cflag |= CLOCAL;
95 TT.termios.c_cc[VTIME] = 0;
96 TT.termios.c_cc[VMIN] = 1;
97 TT.termios.c_oflag = OPOST|ONLCR;
98 TT.termios.c_cflag |= CS8|CREAD|HUPCL|CBAUDEX;
99 // login will disable echo for passwd.
100 TT.termios.c_lflag |= ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOKE;
101 TT.termios.c_cc[VINTR] = CTL('C');
102 TT.termios.c_cc[VQUIT] = CTL('\\');
103 TT.termios.c_cc[VEOF] = CTL('D');
104 TT.termios.c_cc[VEOL] = '\n';
105 TT.termios.c_cc[VKILL] = CTL('U');
106 TT.termios.c_cc[VERASE] = 127; // CERASE
107 TT.termios.c_iflag = ICRNL|IXON|IXOFF;
108 // Set non-zero baud rate. Zero baud rate left it unchanged.
109 if (TT.speeds[0] != 0) xsetspeed(&TT.termios, TT.speeds[0]);
110 if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
111 }
112
113 // Get the baud rate from modems CONNECT mesage, Its of form <junk><BAUD><Junk>
sense_baud(void)114 static void sense_baud(void)
115 {
116 int vmin, speed;
117 ssize_t size;
118 char *ptr;
119
120 vmin = TT.termios.c_cc[VMIN]; // Store old
121 TT.termios.c_cc[VMIN] = 0; // No block even queue is empty.
122 if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
123 size = readall(0, TT.buff, sizeof(TT.buff)-1);
124 if (size > 0) {
125 for (ptr = TT.buff; ptr < TT.buff+size; ptr++) {
126 if (isdigit(*ptr)) {
127 speed = atolx_range(ptr, 0, INT_MAX);
128 if (speed > 0) xsetspeed(&TT.termios, speed);
129 break;
130 }
131 }
132 }
133 TT.termios.c_cc[VMIN] = vmin; //restore old value
134 if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
135 }
136
137 // Print /etc/issue, interpreting escape sequences.
print_issue(void)138 void print_issue(void)
139 {
140 FILE *fp = fopen(TT.f, "r");
141 int ch;
142
143 if (!fp) return;
144 while ((ch = fgetc(fp)) != -1) {
145 if (ch == '\\' || ch == '%') {
146 ch = fgetc(fp);
147 if (ch == 'h' || ch == 'n') xputsn(TT.uts.nodename);
148 else if (ch == 'm') xputsn(TT.uts.machine);
149 else if (ch == 'r') xputsn(TT.uts.release);
150 else if (ch == 's') xputsn(TT.uts.sysname);
151 else if (ch == 'l') xputsn(TT.tty_name);
152 else printf("<bad escape>");
153 } else xputc(ch);
154 }
155 }
156
157 // Read login name and print prompt and Issue file.
read_login_name(void)158 static int read_login_name(void)
159 {
160 tcflush(0, TCIFLUSH); // Flush pending speed switches
161 while (1) {
162 int i = 0;
163
164 if (!FLAG(i)) print_issue();
165
166 printf("%s login: ", TT.uts.nodename);
167 fflush(stdout);
168
169 TT.buff[0] = getchar();
170 if (!TT.buff[0] && TT.sc > 1) return 0; // Switch speed
171 if (TT.buff[0] == '\n') continue;
172 if (TT.buff[0] != '\n')
173 if (!fgets(&TT.buff[1], HOSTNAME_SIZE-1, stdin)) _exit(1);
174 while (i < HOSTNAME_SIZE-1 && isgraph(TT.buff[i])) i++;
175 TT.buff[i] = 0;
176 break;
177 }
178 return 1;
179 }
180
utmp_entry(void)181 static void utmp_entry(void)
182 {
183 struct utmpx entry = {.ut_pid = getpid()}, *ep;
184 int fd;
185
186 // We're responsible for ensuring that the utmp file exists.
187 if (access(_PATH_UTMP, F_OK) && (fd = open(_PATH_UTMP, O_CREAT, 0664)) != -1)
188 close(fd);
189
190 // Find any existing entry.
191 setutxent();
192 while ((ep = getutxent()))
193 if (ep->ut_pid == entry.ut_pid && ep->ut_type >= INIT_PROCESS) break;
194 if (ep) entry = *ep;
195 else entry.ut_type = LOGIN_PROCESS;
196
197 // Modify.
198 entry.ut_tv.tv_sec = time(0);
199 xstrncpy(entry.ut_user, "LOGIN", sizeof(entry.ut_user));
200 xstrncpy(entry.ut_line, ttyname(0) + strlen("/dev/"), sizeof(entry.ut_line));
201 if (FLAG(H)) xstrncpy(entry.ut_host, TT.H, sizeof(entry.ut_host));
202
203 // Write.
204 pututxline(&entry);
205 endutxent();
206 }
207
getty_main(void)208 void getty_main(void)
209 {
210 char ch, *cmd[3] = {TT.l ? : "/bin/login", 0, 0}; // space to add username
211
212 if (!FLAG(f)) TT.f = "/etc/issue";
213 uname(&TT.uts);
214
215 // parse arguments and set $TERM
216 if (isdigit(**toys.optargs)) {
217 parse_speeds(*toys.optargs);
218 if (*++toys.optargs) TT.tty_name = xmprintf("%s", *toys.optargs);
219 } else {
220 TT.tty_name = xmprintf("%s", *toys.optargs);
221 if (*++toys.optargs) parse_speeds(*toys.optargs);
222 }
223 if (*++toys.optargs) setenv("TERM", *toys.optargs, 1);
224
225 open_tty();
226 termios_init();
227 tcsetpgrp(0, getpid());
228 utmp_entry();
229 if (FLAG(I)) xputsn(TT.I);
230 if (FLAG(m)) sense_baud();
231 if (FLAG(t)) alarm(TT.t);
232 if (FLAG(w)) while (readall(0, &ch, 1) != 1) if (ch=='\n' || ch=='\r') break;
233 if (!FLAG(n)) {
234 int index = 1; // 0th we already set.
235
236 for (;;) {
237 if (read_login_name()) break;
238 index %= TT.sc;
239 xsetspeed(&TT.termios, TT.speeds[index]);
240 //Necessary after cfsetspeed
241 if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
242 }
243 cmd[1] = TT.buff; //put the username in the login command line
244 }
245 xexec(cmd);
246 }
247