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/* getty.c - A getty program to get controlling terminal.
*
* Copyright 2012 Sandeep Sharma <sandeep.jack2756@gamil.com>
* Copyright 2013 Kyungwan Han <asura321@gmail.com>
*
* No Standard.
USE_GETTY(NEWTOY(getty, "<2t#<0H:I:l:f:iwnmLh", TOYFLAG_SBIN))
config GETTY
bool "getty"
default n
help
usage: getty [OPTIONS] BAUD_RATE[,BAUD_RATE]... TTY [TERMTYPE]
Wait for a modem to dial into serial port, adjust baud rate, call login.
-h Enable hardware RTS/CTS flow control
-L Set CLOCAL (ignore Carrier Detect state)
-m Get baud rate from modem's CONNECT status message
-n Don't prompt for login name
-w Wait for CR or LF before sending /etc/issue
-i Don't display /etc/issue
-f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue
-l LOGIN Invoke LOGIN instead of /bin/login
-t SEC Terminate after SEC if no login name is read
-I INITSTR Send INITSTR before anything else
-H HOST Log HOST into the utmp file as the hostname
*/
#define FOR_getty
#include "toys.h"
GLOBALS(
char *f, *l, *I, *H;
long t;
char *tty_name, buff[128];
int speeds[20], sc;
struct termios termios;
)
#define CTL(x) ((x) ^ 0100)
#define HOSTNAME_SIZE 32
static void parse_speeds(char *sp)
{
char *ptr;
TT.sc = 0;
while ((ptr = strsep(&sp, ","))) {
TT.speeds[TT.sc] = atolx_range(ptr, 0, INT_MAX);
if (TT.speeds[TT.sc] < 0) perror_exit("bad speed %s", ptr);
if (++TT.sc > 10) perror_exit("too many speeds, max is 10");
}
}
// Get controlling terminal and redirect stdio
static void open_tty(void)
{
if (strcmp(TT.tty_name, "-")) {
if (*(TT.tty_name) != '/') TT.tty_name = xmprintf("/dev/%s", TT.tty_name);
// Sends SIGHUP to all foreground process if Session leader don't die,Ignore
void* handler = signal(SIGHUP, SIG_IGN);
ioctl(0, TIOCNOTTY, 0); // Giveup if there is any controlling terminal
signal(SIGHUP, handler);
if ((setsid() < 0) && (getpid() != getsid(0))) perror_exit("setsid");
xclose(0);
xopen_stdio(TT.tty_name, O_RDWR|O_NDELAY|O_CLOEXEC);
fcntl(0, F_SETFL, fcntl(0, F_GETFL) & ~O_NONBLOCK); // Block read
dup2(0, 1);
dup2(0, 2);
if (ioctl(0, TIOCSCTTY, 1) < 0) perror_msg("ioctl(TIOCSCTTY)");
if (!isatty(0)) perror_exit("/dev/%s: not a tty", TT.tty_name);
chown(TT.tty_name, 0, 0); // change ownership, Hope login will change this
chmod(TT.tty_name, 0620);
} else { // We already have opened TTY
if (setsid() < 0) perror_msg("setsid failed");
if ((fcntl(0, F_GETFL) & (O_RDWR|O_RDONLY|O_WRONLY)) != O_RDWR)
perror_exit("no read/write permission");
}
}
static void termios_init(void)
{
if (tcgetattr(0, &TT.termios) < 0) perror_exit("tcgetattr");
// Flush input and output queues, important for modems!
tcflush(0, TCIOFLUSH);
TT.termios.c_cflag &= (0|CSTOPB|PARENB|PARODD);
#ifdef CRTSCTS
if (FLAG(h)) TT.termios.c_cflag |= CRTSCTS;
#endif
if (FLAG(L)) TT.termios.c_cflag |= CLOCAL;
TT.termios.c_cc[VTIME] = 0;
TT.termios.c_cc[VMIN] = 1;
TT.termios.c_oflag = OPOST|ONLCR;
TT.termios.c_cflag |= CS8|CREAD|HUPCL|CBAUDEX;
// login will disable echo for passwd.
TT.termios.c_lflag |= ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOKE;
TT.termios.c_cc[VINTR] = CTL('C');
TT.termios.c_cc[VQUIT] = CTL('\\');
TT.termios.c_cc[VEOF] = CTL('D');
TT.termios.c_cc[VEOL] = '\n';
TT.termios.c_cc[VKILL] = CTL('U');
TT.termios.c_cc[VERASE] = 127; // CERASE
TT.termios.c_iflag = ICRNL|IXON|IXOFF;
// Set non-zero baud rate. Zero baud rate left it unchanged.
if (TT.speeds[0] != 0) xsetspeed(&TT.termios, TT.speeds[0]);
if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
}
// Get the baud rate from modems CONNECT mesage, Its of form <junk><BAUD><Junk>
static void sense_baud(void)
{
int vmin, speed;
ssize_t size;
char *ptr;
vmin = TT.termios.c_cc[VMIN]; // Store old
TT.termios.c_cc[VMIN] = 0; // No block even queue is empty.
if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
size = readall(0, TT.buff, sizeof(TT.buff)-1);
if (size > 0) {
for (ptr = TT.buff; ptr < TT.buff+size; ptr++) {
if (isdigit(*ptr)) {
speed = atolx_range(ptr, 0, INT_MAX);
if (speed > 0) xsetspeed(&TT.termios, speed);
break;
}
}
}
TT.termios.c_cc[VMIN] = vmin; //restore old value
if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
}
// Print /etc/isuue with taking care of each escape sequence
void write_issue(char *file, struct utsname *uts)
{
char buff[20] = {0,};
int fd = open(TT.f, O_RDONLY), size;
if (fd < 0) return;
while ((size = readall(fd, buff, 1)) > 0) {
char *ch = buff;
if (*ch == '\\' || *ch == '%') {
if (readall(fd, buff, 1) <= 0) perror_exit("readall");
if (*ch == 's') fputs(uts->sysname, stdout);
if (*ch == 'n'|| *ch == 'h') fputs(uts->nodename, stdout);
if (*ch == 'r') fputs(uts->release, stdout);
if (*ch == 'm') fputs(uts->machine, stdout);
if (*ch == 'l') fputs(TT.tty_name, stdout);
} else xputc(*ch);
}
}
// Read login name and print prompt and Issue file.
static int read_login_name(void)
{
tcflush(0, TCIFLUSH); // Flush pending speed switches
while (1) {
struct utsname uts;
int i = 0;
uname(&uts);
if (!FLAG(i)) write_issue(TT.f, &uts);
printf("%s login: ", uts.nodename);
xflush(1);
TT.buff[0] = getchar();
if (!TT.buff[0] && TT.sc > 1) return 0; // Switch speed
if (TT.buff[0] == '\n') continue;
if (TT.buff[0] != '\n')
if (!fgets(&TT.buff[1], HOSTNAME_SIZE-1, stdin)) _exit(1);
while (i < HOSTNAME_SIZE-1 && isgraph(TT.buff[i])) i++;
TT.buff[i] = 0;
break;
}
return 1;
}
static void utmp_entry(void)
{
struct utmpx entry = {.ut_pid = getpid()}, *ep;
int fd;
// We're responsible for ensuring that the utmp file exists.
if (access(_PATH_UTMP, F_OK) && (fd = open(_PATH_UTMP, O_CREAT, 0664)) != -1)
close(fd);
// Find any existing entry.
setutxent();
while ((ep = getutxent()))
if (ep->ut_pid == entry.ut_pid && ep->ut_type >= INIT_PROCESS) break;
if (ep) entry = *ep;
else entry.ut_type = LOGIN_PROCESS;
// Modify.
entry.ut_tv.tv_sec = time(0);
xstrncpy(entry.ut_user, "LOGIN", sizeof(entry.ut_user));
xstrncpy(entry.ut_line, ttyname(0) + strlen("/dev/"), sizeof(entry.ut_line));
if (FLAG(H)) xstrncpy(entry.ut_host, TT.H, sizeof(entry.ut_host));
// Write.
pututxline(&entry);
endutxent();
}
void getty_main(void)
{
char ch, *cmd[3] = {TT.l ? : "/bin/login", 0, 0}; // space to add username
if (!FLAG(f)) TT.f = "/etc/issue";
// parse arguments and set $TERM
if (isdigit(**toys.optargs)) {
parse_speeds(*toys.optargs);
if (*++toys.optargs) TT.tty_name = xmprintf("%s", *toys.optargs);
} else {
TT.tty_name = xmprintf("%s", *toys.optargs);
if (*++toys.optargs) parse_speeds(*toys.optargs);
}
if (*++toys.optargs) setenv("TERM", *toys.optargs, 1);
open_tty();
termios_init();
tcsetpgrp(0, getpid());
utmp_entry();
if (FLAG(I)) xputsn(TT.I);
if (FLAG(m)) sense_baud();
if (FLAG(t)) alarm(TT.t);
if (FLAG(w)) while (readall(0, &ch, 1) != 1) if (ch=='\n' || ch=='\r') break;
if (!FLAG(n)) {
int index = 1; // 0th we already set.
for (;;) {
if (read_login_name()) break;
index %= TT.sc;
xsetspeed(&TT.termios, TT.speeds[index]);
//Necessary after cfsetspeed
if (tcsetattr(0, TCSANOW, &TT.termios) < 0) perror_exit("tcsetattr");
}
cmd[1] = TT.buff; //put the username in the login command line
}
xexec(cmd);
}
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