#define MAX_SPEED 10 /* max. nr. of baud rates */
struct globals {
- unsigned timeout; /* time-out period */
+ unsigned timeout;
const char *login; /* login program */
const char *fakehost;
- const char *tty; /* name of tty */
+ const char *tty_name;
char *initstring; /* modem init string */
const char *issue; /* alternative issue file */
int numspeed; /* number of baud rates to try */
int speeds[MAX_SPEED]; /* baud rates to be tried */
unsigned char eol; /* end-of-line char seen (CR or NL) */
- struct termios termios; /* terminal mode bits */
+ struct termios tty_attrs;
char line_buf[128];
};
debug("after getopt\n");
/* We loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
- G.tty = argv[0]; /* tty name */
- ts = argv[1]; /* baud rate(s) */
+ G.tty_name = argv[0];
+ ts = argv[1]; /* baud rate(s) */
if (isdigit(argv[0][0])) {
/* A number first, assume it's a speed (BSD style) */
- G.tty = ts; /* tty name is in argv[1] */
- ts = argv[0]; /* baud rate(s) */
+ G.tty_name = ts; /* tty name is in argv[1] */
+ ts = argv[0]; /* baud rate(s) */
}
parse_speeds(ts);
- applet_name = xasprintf("getty: %s", G.tty);
if (argv[2])
xsetenv("TERM", argv[2]);
static void open_tty(void)
{
/* Set up new standard input, unless we are given an already opened port */
- if (NOT_LONE_DASH(G.tty)) {
- if (G.tty[0] != '/')
- G.tty = xasprintf("/dev/%s", G.tty); /* will leak it */
+ if (NOT_LONE_DASH(G.tty_name)) {
+ if (G.tty_name[0] != '/')
+ G.tty_name = xasprintf("/dev/%s", G.tty_name); /* will leak it */
/* Open the tty as standard input */
debug("open(2)\n");
close(0);
- xopen(G.tty, O_RDWR | O_NONBLOCK); /* uses fd 0 */
+ xopen(G.tty_name, O_RDWR | O_NONBLOCK); /* uses fd 0 */
/* Set proper protections and ownership */
fchown(0, 0, 0); /* 0:0 */
fchmod(0, 0620); /* crw--w---- */
} else {
+ char *n;
/*
- * Standard input should already be connected to an open port. Make
- * sure it is open for read/write.
+ * Standard input should already be connected to an open port.
+ * Make sure it is open for read/write.
*/
if ((fcntl(0, F_GETFL) & (O_RDWR|O_RDONLY|O_WRONLY)) != O_RDWR)
bb_error_msg_and_die("stdin is not open for read/write");
+
+ /* Try to get real tty name instead of "-" */
+ n = xmalloc_ttyname(0);
+ if (n)
+ G.tty_name = n;
}
+ applet_name = xasprintf("getty: %s", skip_dev_pfx(G.tty_name));
}
-static void set_termios(void)
+static void set_tty_attrs(void)
{
- if (tcsetattr_stdin_TCSANOW(&G.termios) < 0)
+ if (tcsetattr_stdin_TCSANOW(&G.tty_attrs) < 0)
bb_perror_msg_and_die("tcsetattr");
}
-/* We manipulate termios this way:
- * - first, we read existing termios settings
- * - termios_init modifies some parts and sets it
- * - auto_baud and/or BREAK processing can set different speed and set termios
- * - termios_final again modifies some parts and sets termios before
+/* We manipulate tty_attrs this way:
+ * - first, we read existing tty_attrs
+ * - init_tty_attrs modifies some parts and sets it
+ * - auto_baud and/or BREAK processing can set different speed and set tty attrs
+ * - finalize_tty_attrs again modifies some parts and sets tty attrs before
* execing login
*/
-static void termios_init(int speed)
+static void init_tty_attrs(int speed)
{
/* Try to drain output buffer, with 5 sec timeout.
* Added on request from users of ~600 baud serial interface
/* Set speed if it wasn't specified as "0" on command line */
if (speed != B0)
- cfsetspeed(&G.termios, speed);
+ cfsetspeed(&G.tty_attrs, speed);
- /* Initial termios settings: 8-bit characters, raw mode, blocking i/o.
+ /* Initial settings: 8-bit characters, raw mode, blocking i/o.
* Special characters are set after we have read the login name; all
* reads will be done in raw mode anyway.
*/
/* Clear all bits except: */
- G.termios.c_cflag &= (0
+ G.tty_attrs.c_cflag &= (0
/* 2 stop bits (1 otherwise)
* Enable parity bit (both on input and output)
* Odd parity (else even)
#endif
);
/* Set: 8 bits; hang up (drop DTR) on last close; enable receive */
- G.termios.c_cflag |= CS8 | HUPCL | CREAD;
+ G.tty_attrs.c_cflag |= CS8 | HUPCL | CREAD;
if (option_mask32 & F_LOCAL) {
/* ignore Carrier Detect pin:
* opens don't block when CD is low,
* losing CD doesn't hang up processes whose ctty is this tty
*/
- G.termios.c_cflag |= CLOCAL;
+ G.tty_attrs.c_cflag |= CLOCAL;
}
#ifdef CRTSCTS
if (option_mask32 & F_RTSCTS)
- G.termios.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
+ G.tty_attrs.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
#endif
- G.termios.c_iflag = 0;
- G.termios.c_lflag = 0;
+ G.tty_attrs.c_iflag = 0;
+ G.tty_attrs.c_lflag = 0;
/* non-raw output; add CR to each NL */
- G.termios.c_oflag = OPOST | ONLCR;
+ G.tty_attrs.c_oflag = OPOST | ONLCR;
- G.termios.c_cc[VMIN] = 1; /* block reads if < 1 char is available */
- G.termios.c_cc[VTIME] = 0; /* no timeout (reads block forever) */
+ G.tty_attrs.c_cc[VMIN] = 1; /* block reads if < 1 char is available */
+ G.tty_attrs.c_cc[VTIME] = 0; /* no timeout (reads block forever) */
#ifdef __linux__
- G.termios.c_line = 0;
+ G.tty_attrs.c_line = 0;
#endif
- set_termios();
+ set_tty_attrs();
debug("term_io 2\n");
}
-static void termios_final(void)
+static void finalize_tty_attrs(void)
{
/* software flow control on output (stop sending if XOFF is recvd);
* and on input (send XOFF when buffer is full)
*/
- G.termios.c_iflag |= IXON | IXOFF;
+ G.tty_attrs.c_iflag |= IXON | IXOFF;
if (G.eol == '\r') {
- G.termios.c_iflag |= ICRNL; /* map CR on input to NL */
+ G.tty_attrs.c_iflag |= ICRNL; /* map CR on input to NL */
}
/* Other bits in c_iflag:
* IXANY Any recvd char enables output (any char is also a XON)
* echo kill char specially, not as ^c (ECHOKE controls how exactly);
* erase all input via BS-SP-BS on kill char (else go to next line)
*/
- G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
+ G.tty_attrs.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
/* Other bits in c_lflag:
* XCASE Map uppercase to \lowercase [tried, doesn't work]
* ECHONL Echo NL even if ECHO is not set
* (why "stty sane" unsets this bit?)
*/
- G.termios.c_cc[VINTR] = DEF_INTR;
- G.termios.c_cc[VQUIT] = DEF_QUIT;
- G.termios.c_cc[VEOF] = DEF_EOF;
- G.termios.c_cc[VEOL] = DEF_EOL;
+ G.tty_attrs.c_cc[VINTR] = DEF_INTR;
+ G.tty_attrs.c_cc[VQUIT] = DEF_QUIT;
+ G.tty_attrs.c_cc[VEOF] = DEF_EOF;
+ G.tty_attrs.c_cc[VEOL] = DEF_EOL;
#ifdef VSWTC
- G.termios.c_cc[VSWTC] = DEF_SWITCH;
+ G.tty_attrs.c_cc[VSWTC] = DEF_SWITCH;
#endif
#ifdef VSWTCH
- G.termios.c_cc[VSWTCH] = DEF_SWITCH;
+ G.tty_attrs.c_cc[VSWTCH] = DEF_SWITCH;
#endif
- G.termios.c_cc[VKILL] = DEF_KILL;
+ G.tty_attrs.c_cc[VKILL] = DEF_KILL;
/* Other control chars:
* VEOL2
* VERASE, VWERASE - (word) erase. we may set VERASE in get_logname
* VSTART, VSTOP - chars used for IXON/IXOFF
*/
- set_termios();
+ set_tty_attrs();
}
/* extract baud rate from modem status message */
* modem status messages is enabled.
*/
- G.termios.c_cc[VMIN] = 0; /* don't block reads (min read is 0 chars) */
- set_termios();
+ G.tty_attrs.c_cc[VMIN] = 0; /* don't block reads (min read is 0 chars) */
+ set_tty_attrs();
/*
* Wait for a while, then read everything the modem has said so far and
if (isdigit(*bp)) {
speed = bcode(bp);
if (speed > 0)
- cfsetspeed(&G.termios, speed);
+ cfsetspeed(&G.tty_attrs, speed);
break;
}
}
}
/* Restore terminal settings */
- G.termios.c_cc[VMIN] = 1; /* restore to value set by termios_init */
- set_termios();
+ G.tty_attrs.c_cc[VMIN] = 1; /* restore to value set by init_tty_attrs */
+ set_tty_attrs();
}
/* get user name, establish parity, speed, erase, kill, eol;
/* Write issue file and prompt */
#ifdef ISSUE
if (!(option_mask32 & F_NOISSUE))
- print_login_issue(G.issue, G.tty);
+ print_login_issue(G.issue, G.tty_name);
#endif
print_login_prompt();
goto got_logname;
case BS:
case DEL:
- G.termios.c_cc[VERASE] = c;
+ G.tty_attrs.c_cc[VERASE] = c;
if (bp > G.line_buf) {
full_write(STDOUT_FILENO, "\010 \010", 3);
bp--;
return G.line_buf;
}
+static void alarm_handler(int sig UNUSED_PARAM)
+{
+ finalize_tty_attrs();
+ _exit(EXIT_SUCCESS);
+}
+
int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int getty_main(int argc UNUSED_PARAM, char **argv)
{
int n;
- pid_t pid;
+ pid_t pid, tsid;
char *logname;
INIT_G();
/* Parse command-line arguments */
parse_args(argv);
- logmode = LOGMODE_NONE;
+ /* Create new session and pgrp, lose controlling tty */
+ pid = setsid(); /* this also gives us our pid :) */
+ if (pid < 0) {
+ int fd;
+ /* :(
+ * docs/ctty.htm says:
+ * "This is allowed only when the current process
+ * is not a process group leader".
+ * Thus, setsid() will fail if we _already_ are
+ * a session leader - which is quite possible for getty!
+ */
+ pid = getpid();
+ if (getsid(0) != pid)
+ bb_perror_msg_and_die("setsid");
+ /* Looks like we are already a session leader.
+ * In this case (setsid failed) we may still have ctty,
+ * and it may be different from tty we need to control!
+ * If we still have ctty, on Linux ioctl(TIOCSCTTY)
+ * (which we are going to call a bit later) always fails.
+ * Try to drop ctty now to prevent that.
+ */
+ fd = open("/dev/tty", O_RDWR);
+ if (fd >= 0) {
+ ioctl(fd, TIOCNOTTY);
+ close(fd);
+ }
+ }
- /* Create new session, lose controlling tty, if any */
- /* docs/ctty.htm says:
- * "This is allowed only when the current process
- * is not a process group leader" - is this a problem? */
- setsid();
- /* close stdio, and stray descriptors, just in case */
+ /* Close stdio, and stray descriptors, just in case */
n = xopen(bb_dev_null, O_RDWR);
/* dup2(n, 0); - no, we need to handle "getty - 9600" too */
xdup2(n, 1);
#endif
/* Open the tty as standard input, if it is not "-" */
- /* If it's not "-" and not taken yet, it will become our ctty */
debug("calling open_tty\n");
open_tty();
- ndelay_off(0);
+ ndelay_off(STDIN_FILENO);
debug("duping\n");
- xdup2(0, 1);
- xdup2(0, 2);
+ xdup2(STDIN_FILENO, 1);
+ xdup2(STDIN_FILENO, 2);
+
+ /* Steal ctty if we don't have it yet */
+ tsid = tcgetsid(STDIN_FILENO);
+ if (tsid < 0 || pid != tsid) {
+ if (ioctl(STDIN_FILENO, TIOCSCTTY, /*force:*/ (long)1) < 0)
+ bb_perror_msg_and_die("TIOCSCTTY");
+ }
+
+#ifdef __linux__
+ /* Make ourself a foreground process group within our session */
+ if (tcsetpgrp(STDIN_FILENO, pid) < 0)
+ bb_perror_msg_and_die("tcsetpgrp");
+#endif
/*
* The following ioctl will fail if stdin is not a tty, but also when
* by patching the SunOS kernel variable "zsadtrlow" to a larger value;
* 5 seconds seems to be a good value.
*/
- if (tcgetattr(STDIN_FILENO, &G.termios) < 0)
+ if (tcgetattr(STDIN_FILENO, &G.tty_attrs) < 0)
bb_perror_msg_and_die("tcgetattr");
- pid = getpid();
-#ifdef __linux__
-// FIXME: do we need this? Otherwise "-" case seems to be broken...
- // /* Forcibly make fd 0 our controlling tty, even if another session
- // * has it as a ctty. (Another session loses ctty). */
- // ioctl(STDIN_FILENO, TIOCSCTTY, (void*)1);
- /* Make ourself a foreground process group within our session */
- tcsetpgrp(STDIN_FILENO, pid);
-#endif
-
/* Update the utmp file. This tty is ours now! */
- update_utmp(pid, LOGIN_PROCESS, G.tty, "LOGIN", G.fakehost);
+ update_utmp(pid, LOGIN_PROCESS, G.tty_name, "LOGIN", G.fakehost);
- /* Initialize the termios settings (raw mode, eight-bit, blocking i/o) */
- debug("calling termios_init\n");
- termios_init(G.speeds[0]);
+ /* Initialize tty attrs (raw mode, eight-bit, blocking i/o) */
+ debug("calling init_tty_attrs\n");
+ init_tty_attrs(G.speeds[0]);
/* Write the modem init string and DON'T flush the buffers */
if (option_mask32 & F_INITSTRING) {
auto_baud();
/* Set the optional timer */
+ signal(SIGALRM, alarm_handler);
alarm(G.timeout); /* if 0, alarm is not set */
-//BUG: death by signal won't restore termios
/* Optionally wait for CR or LF before writing /etc/issue */
if (option_mask32 & F_WAITCRLF) {
logname = NULL;
if (!(option_mask32 & F_NOPROMPT)) {
- /* NB: termios_init already set line speed
+ /* NB: init_tty_attrs already set line speed
* to G.speeds[0] */
int baud_index = 0;
break;
/* We are here only if G.numspeed > 1 */
baud_index = (baud_index + 1) % G.numspeed;
- cfsetspeed(&G.termios, G.speeds[baud_index]);
- set_termios();
+ cfsetspeed(&G.tty_attrs, G.speeds[baud_index]);
+ set_tty_attrs();
}
}
/* Disable timer */
alarm(0);
- /* Finalize the termios settings */
- termios_final();
+ finalize_tty_attrs();
/* Now the newline character should be properly written */
full_write(STDOUT_FILENO, "\n", 1);
TTYNAME_SIZE = 32,
};
+struct globals {
+ struct termios tty_attrs;
+} FIX_ALIASING;
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { } while (0)
+
+
#if ENABLE_FEATURE_NOLOGIN
static void die_if_nologin(void)
{
static void alarm_handler(int sig UNUSED_PARAM)
{
- /* This is the escape hatch! Poor serial line users and the like
+ /* This is the escape hatch! Poor serial line users and the like
* arrive here when their connection is broken.
* We don't want to block here */
- ndelay_on(1);
- printf("\r\nLogin timed out after %d seconds\r\n", TIMEOUT);
+ ndelay_on(STDOUT_FILENO);
+ /* Test for correct attr restoring:
+ * run "getty 0 -" from a shell, enter bogus username, stop at
+ * password prompt, let it time out. Without the tcsetattr below,
+ * when you are back at shell prompt, echo will be still off.
+ */
+ tcsetattr_stdin_TCSANOW(&G.tty_attrs);
+ printf("\r\nLogin timed out after %u seconds\r\n", TIMEOUT);
fflush_all();
/* unix API is brain damaged regarding O_NONBLOCK,
* we should undo it, or else we can affect other processes */
- ndelay_off(1);
+ ndelay_off(STDOUT_FILENO);
_exit(EXIT_SUCCESS);
}
pid_t child_pid;
#endif
- username[0] = '\0';
- signal(SIGALRM, alarm_handler);
- alarm(TIMEOUT);
+ INIT_G();
/* More of suid paranoia if called by non-root: */
/* Clear dangerous stuff, set PATH */
* (The name of the function is misleading. Not daemonizing here.) */
bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE | DAEMON_CLOSE_EXTRA_FDS, NULL);
+ username[0] = '\0';
opt = getopt32(argv, "f:h:p", &opt_user, &opt_host);
if (opt & LOGIN_OPT_f) {
if (!run_by_root)
if (argv[0]) /* user from command line (getty) */
safe_strncpy(username, argv[0], sizeof(username));
- /* Let's find out and memorize our tty */
- if (!isatty(STDIN_FILENO) || !isatty(STDOUT_FILENO) || !isatty(STDERR_FILENO))
+ /* Save tty attributes - and by doing it, check that it's indeed a tty */
+ if (tcgetattr(STDIN_FILENO, &G.tty_attrs) < 0
+ || !isatty(STDOUT_FILENO)
+ /*|| !isatty(STDERR_FILENO) - no, guess some people might want to redirect this */
+ ) {
return EXIT_FAILURE; /* Must be a terminal */
+ }
+
+ /* We install timeout handler only _after_ we saved G.tty_attrs */
+ signal(SIGALRM, alarm_handler);
+ alarm(TIMEOUT);
+
+ /* Find out and memorize our tty name */
full_tty = xmalloc_ttyname(STDIN_FILENO);
if (!full_tty)
full_tty = xstrdup("UNKNOWN");
if (!pw->pw_passwd[0])
break;
fake_it:
- /* authorization takes place here */
+ /* Password reading and authorization takes place here.
+ * Note that reads (in no-echo mode) trash tty attributes.
+ * If we get interrupted by SIGALRM, we need to restore attrs.
+ */
if (correct_password(pw))
break;
#endif /* ENABLE_PAM */
projects / oweals / busybox.git / commitdiff