Ensure a proper session on the terminal line, that is do a
vhangup() and become the controlling terminal. After this
determine if the terminal line a virtual console by using
the ioctl TIOCMGET to get the status modem bits of a serial
line which is a invalid argument on a virtual console.
Signed-off-by: Werner Fink <werner@xxxxxxx>
---
term-utils/agetty.8 | 3 +
term-utils/agetty.c | 158 +++++++++++++++++++++++++++++++++++++++-----------
2 files changed, 126 insertions(+), 35 deletions(-)
diff --git a/term-utils/agetty.8 b/term-utils/agetty.8
index 21a07a0..4abd819 100644
--- a/term-utils/agetty.8
+++ b/term-utils/agetty.8
@@ -152,6 +152,9 @@ space parity, 7 bit characters, and ASCII CR (13) end-of-line character.
Beware that the program that \fBagetty\fR starts (usually /bin/login)
is run as root.
.TP
+\-R, \-\-hangup
+Do call vhangup() for a virtually hangup of the specified terminal.
+.TP
\-s, \-\-keep-baud
Try to keep the existing baud rate. The baud rates from
the command line are used when agetty receives a BREAK character.
diff --git a/term-utils/agetty.c b/term-utils/agetty.c
index 5ff805f..55adaf4 100644
--- a/term-utils/agetty.c
+++ b/term-utils/agetty.c
@@ -16,6 +16,7 @@
#include <termios.h>
#include <signal.h>
#include <errno.h>
+#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
@@ -28,6 +29,7 @@
#include <sys/socket.h>
#include <netdb.h>
#include <langinfo.h>
+#include <grp.h>
#include "strutils.h"
#include "writeall.h"
@@ -147,6 +149,8 @@ struct options {
#define F_KEEPSPEED (1<<9) /* follow baud rate from kernel */
#define F_KEEPCFLAGS (1<<10) /* reuse c_cflags setup from kernel */
#define F_EIGHTBITS (1<<11) /* Assume 8bit-clean tty */
+#define F_VCONSOLE (1<<12) /* This is a virtual console */
+#define F_HANGUP (1<<13) /* Do call vhangup(2) */
/* Storage for things detected while the login name was read. */
struct chardata {
@@ -256,11 +260,21 @@ int main(int argc, char **argv)
0, /* no baud rates known yet */
{ 0 }
};
+ struct sigaction sa, sa_hup, sa_quit, sa_int;
+ sigset_t set;
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
+ /* In case vhangup(2) has to called */
+ sa.sa_handler = SIG_IGN;
+ sa.sa_flags = SA_RESTART;
+ sigemptyset (&sa.sa_mask);
+ sigaction(SIGHUP, &sa, &sa_hup);
+ sigaction(SIGQUIT, &sa, &sa_quit);
+ sigaction(SIGINT, &sa, &sa_int);
+
#ifdef DEBUGGING
dbf = fopen("/dev/ttyp0", "w");
for (int i = 1; i < argc; i++)
@@ -270,10 +284,6 @@ int main(int argc, char **argv)
/* Parse command-line arguments. */
parse_args(argc, argv, &options);
-#ifdef __linux__
- setsid();
-#endif
-
/* Update the utmp file. */
#ifdef SYSV_STYLE
update_utmp(&options);
@@ -284,6 +294,12 @@ int main(int argc, char **argv)
/* Open the tty as standard { input, output, error }. */
open_tty(options.tty, &termios, &options);
+ /* Unmask SIGHUP if inherited */
+ sigemptyset(&set);
+ sigaddset(&set, SIGHUP);
+ sigprocmask(SIG_UNBLOCK, &set, NULL);
+ sigaction(SIGHUP, &sa_hup, NULL);
+
tcsetpgrp(STDIN_FILENO, getpid());
/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
debug("calling termio_init\n");
@@ -293,7 +309,7 @@ int main(int argc, char **argv)
if (options.flags & F_INITSTRING) {
debug("writing init string\n");
write_all(STDOUT_FILENO, options.initstring,
- strlen(options.initstring));
+ strlen(options.initstring));
}
if (!(options.flags & F_LOCAL))
@@ -345,6 +361,9 @@ int main(int argc, char **argv)
/* Now the newline character should be properly written. */
write_all(STDOUT_FILENO, "\n", 1);
+ sigaction (SIGQUIT, &sa_quit, NULL);
+ sigaction (SIGINT, &sa_int, NULL);
+
/* Let the login program take care of password validation. */
execl(options.login, options.login, "--", logname, NULL);
log_err(_("%s: can't exec %s: %m"), options.tty, options.login);
@@ -361,7 +380,7 @@ static void parse_args(int argc, char **argv, struct options *op)
VERSION_OPTION = CHAR_MAX + 1,
HELP_OPTION
};
- static const struct option longopts[] = {
+ const struct option longopts[] = {
{ "8bits", no_argument, 0, '8' },
{ "noreset", no_argument, 0, 'c' },
{ "issue-file", required_argument, 0, 'f' },
@@ -373,6 +392,7 @@ static void parse_args(int argc, char **argv, struct options *op)
{ "local-line", no_argument, 0, 'L' },
{ "extract-baud", no_argument, 0, 'm' },
{ "skip-login", no_argument, 0, 'n' },
+ { "hangup", no_argument, 0, 'R' },
{ "keep-baud", no_argument, 0, 's' },
{ "timeout", required_argument, 0, 't' },
{ "detect-case", no_argument, 0, 'U' },
@@ -382,7 +402,7 @@ static void parse_args(int argc, char **argv, struct options *op)
{ NULL, 0, 0, 0 }
};
- while ((c = getopt_long(argc, argv, "8cf:hH:iI:l:Lmnst:Uw", longopts,
+ while ((c = getopt_long(argc, argv, "8cf:hH:iI:l:LmnsRt:Uw", longopts,
NULL)) != -1) {
switch (c) {
case '8':
@@ -420,6 +440,9 @@ static void parse_args(int argc, char **argv, struct options *op)
case 'n':
op->flags |= F_NOPROMPT;
break;
+ case 'R':
+ op->flags |= F_HANGUP;
+ break;
case 's':
op->flags |= F_KEEPSPEED;
break;
@@ -627,43 +650,101 @@ static void update_utmp(struct options *op)
/* Set up tty as stdin, stdout & stderr. */
static void open_tty(char *tty, struct termios *tp, struct options *op)
{
- /* Get rid of the present outputs. */
- close(STDOUT_FILENO);
- close(STDERR_FILENO);
- errno = 0;
+ const pid_t pid = getpid();
+ int serial;
- /*
- * Set up new standard input, unless we are given an already opened
- * port.
- */
- if (strcmp(tty, "-")) {
+ /* Set up new standard input, unless we are given an already opened port. */
+
+ if (strcmp(tty, "-") != 0) {
+ char buf[PATH_MAX+1];
+ struct group *gr = NULL;
struct stat st;
+ int fd, len;
+ pid_t tid;
+ gid_t gid = 0;
+
+ /* Use tty group if available */
+ if ((gr = getgrnam("tty")))
+ gid = gr->gr_gid;
+
+ if (((len = snprintf(buf, sizeof(buf), "/dev/%s", tty)) >= (int)sizeof(buf)) || (len < 0))
+ log_err(_("/dev/%s: cannot open as standard input: %m"), tty);
+
+ /*
+ * There is always a race between this reset and the call to
+ * vhangup() that s.o. can use to get access to your tty.
+ * Linux login(1) will change tty permissions. Use root owner and group
+ * with permission -rw------- for the period between getty and login.
+ */
+ if (chown (buf, 0, gid) || chmod (buf, (gid ? 0660 : 0600))) {
+ if (errno == EROFS)
+ log_warn("%s: %m", buf);
+ else
+ log_err("%s: %m", buf);
+ }
- /* Sanity checks. */
- if (chdir("/dev"))
- log_err(_("/dev: chdir() failed: %m"));
- if (stat(tty, &st) < 0)
- log_err("/dev/%s: %m", tty);
+ /* Open the tty as standard input. */
+ if ((fd = open(buf, O_RDWR|O_NOCTTY|O_NONBLOCK, 0)) < 0)
+ log_err(_("/dev/%s: cannot open as standard input: %m"), tty);
+
+ /* Sanity checks... */
+ if (!isatty (fd))
+ log_err(_("/dev/%s: not a character device"), tty);
+ if (fstat(fd, &st) < 0)
+ log_err ("%s: %m", buf);
if ((st.st_mode & S_IFMT) != S_IFCHR)
log_err(_("/dev/%s: not a character device"), tty);
- /* Open the tty as standard input. */
+ if (((tid = tcgetsid(fd)) < 0) || (pid != tid)) {
+ if (ioctl (fd, TIOCSCTTY, 1) == -1)
+ log_err("/dev/%s: cannot get controlling tty: %m", tty);
+ }
+
+ if (op->flags & F_HANGUP) {
+ /*
+ * vhangup() will replace all open file descriptors in the kernel
+ * that point to our controlling tty by a dummy that will deny
+ * further reading/writing to our device. It will also reset the
+ * tty to sane defaults, so we don't have to modify the tty device
+ * for sane settings. We also get a SIGHUP/SIGCONT.
+ */
+ if (vhangup())
+ log_err("/dev/%s: vhangup() failed: %m", tty);
+ (void)ioctl(fd, TIOCNOTTY);
+ }
+
+ (void) close(fd);
close(STDIN_FILENO);
errno = 0;
debug("open(2)\n");
- if (open(tty, O_RDWR | O_NONBLOCK, 0) != 0)
- log_err(_("/dev/%s: cannot open as standard input: %m"),
- tty);
+ if (open(buf, O_RDWR|O_NOCTTY|O_NONBLOCK, 0) != 0)
+ log_err(_("/dev/%s: cannot open as standard input: %m"), tty);
+ if (((tid = tcgetsid(STDIN_FILENO)) < 0) || (pid != tid)) {
+ if (ioctl (STDIN_FILENO, TIOCSCTTY, 1) == -1)
+ log_err("/dev/%s: cannot get controlling tty: %m", tty);
+ }
+
} else {
+
/*
* Standard input should already be connected to an open port. Make
* sure it is open for read/write.
*/
+
if ((fcntl(STDIN_FILENO, F_GETFL, 0) & O_RDWR) != O_RDWR)
log_err(_("%s: not open for read/write"), tty);
+
}
+ if (tcsetpgrp(STDIN_FILENO, pid))
+ log_err("/dev/%s: cannot set process group: %m", tty);
+
+ /* Get rid of the present outputs. */
+ close(STDOUT_FILENO);
+ close(STDERR_FILENO);
+ errno = 0;
+
/* Set up standard output and standard error file descriptors. */
debug("duping\n");
@@ -671,6 +752,9 @@ static void open_tty(char *tty, struct termios *tp, struct options *op)
if (dup(STDIN_FILENO) != 1 || dup(STDIN_FILENO) != 2)
log_err(_("%s: dup problem: %m"), tty);
+ /* make stdio unbuffered for slow modem lines */
+ setvbuf(stdout, NULL, _IONBF, 0);
+
/*
* The following ioctl will fail if stdin is not a tty, but also when
* there is noise on the modem control lines. In the latter case, the
@@ -686,12 +770,16 @@ static void open_tty(char *tty, struct termios *tp, struct options *op)
log_err("%s: tcgetattr: %m", tty);
/*
- * Linux login(1) will change tty permissions. Use root owner and group
- * with permission -rw------- for the period between getty and login.
+ * Detect if this is a virtual console or serial/modem line.
+ * In case of a virtual console the ioctl TIOCMGET fails and
+ * the error number will be set to EINVAL.
*/
- ignore_result(chown(tty, 0, 0));
- ignore_result(chmod(tty, 0600));
- errno = 0;
+ if (ioctl(STDIN_FILENO, TIOCMGET, &serial) < 0 && (errno = EINVAL)) {
+ op->flags |= F_VCONSOLE;
+ if (!op->term)
+ op->term = DEFAULT_VCTERM;
+ } else if (!op->term)
+ op->term = DEFAULT_STERM;
setenv("TERM", op->term, 1);
}
@@ -819,17 +907,15 @@ static void do_prompt(struct options *op, struct termios *tp)
{
#ifdef ISSUE
FILE *fd;
- int oflag;
- int c;
- struct utsname uts;
-
- uname(&uts);
#endif /* ISSUE */
/* Issue not in use, start with a new line. */
write_all(STDOUT_FILENO, "\r\n", 2);
+
#ifdef ISSUE
if ((op->flags & F_ISSUE) && (fd = fopen(op->issue, "r"))) {
+ int c, oflag;
+
/* Save current setting. */
oflag = tp->c_oflag;
/* Map new line in output to carriage return & new line. */
@@ -1113,6 +1199,7 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
" -L, --local-line force local line\n"
" -m, --extract-baud extract baud rate during connect\n"
" -n, --skip-login do not prompt for login\n"
+ " -R, --hangup do virtually hangup on the tty\n"
" -s, --keep-baud try to keep baud rate after break\n"
" -t, --timeout NUMBER login process timeout\n"
" -U, --detect-case detect uppercase terminal\n"
@@ -1197,6 +1284,7 @@ static void output_special_char(unsigned char c, struct options *op,
{
struct utsname uts;
(void) uname(&uts);
+
switch (c) {
case 's':
(void) printf ("%s", uts.sysname);
--
1.6.0.2
--
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