int
main(int argc, char **argv)
{
const int exit_sig[] = {SIGINT, SIGTERM, SIGHUP};
char *fqdn = NULL;
struct passwd *passwd;
struct tlog_writer *writer = NULL;
clockid_t clock_id;
struct timespec timestamp;
struct tlog_sink *sink = NULL;
tlog_grc grc;
ssize_t rc;
int master_fd;
pid_t child_pid;
unsigned int session_id;
sig_atomic_t last_sigwinch_caught = 0;
sig_atomic_t new_sigwinch_caught;
sig_atomic_t last_alarm_caught = 0;
sig_atomic_t new_alarm_caught;
bool alarm_set = false;
bool io_pending = false;
bool term_attrs_set = false;
struct termios orig_termios;
struct termios raw_termios;
struct winsize winsize;
struct winsize new_winsize;
size_t i, j;
struct sigaction sa;
struct pollfd fds[FD_IDX_NUM];
uint8_t input_buf[BUF_SIZE];
size_t input_pos = 0;
size_t input_len = 0;
uint8_t output_buf[BUF_SIZE];
size_t output_pos = 0;
size_t output_len = 0;
struct tlog_pkt pkt = TLOG_PKT_VOID;
int status = 1;
(void)argv;
if (argc > 1) {
fprintf(stderr, "Arguments are not accepted\n");
goto cleanup;
}
/* Get host FQDN */
grc = get_fqdn(&fqdn);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed retrieving host FQDN: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
/* Get session ID */
grc = get_session_id(&session_id);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed retrieving session ID: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
/* Open syslog */
openlog("tlog", LOG_NDELAY, LOG_LOCAL0);
/* Create the syslog writer */
grc = tlog_syslog_writer_create(&writer, LOG_INFO);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed creating syslog writer: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
/* Get effective user entry */
errno = 0;
passwd = getpwuid(geteuid());
if (passwd == NULL) {
if (errno == 0)
fprintf(stderr, "User entry not found\n");
else
fprintf(stderr, "Failed retrieving user entry: %s\n",
strerror(errno));
goto cleanup;
}
/*
* Choose the clock: try to use coarse monotonic clock (which is faster),
* if it provides resolution of at least one millisecond.
*/
if (clock_getres(CLOCK_MONOTONIC_COARSE, ×tamp) == 0 &&
timestamp.tv_sec == 0 && timestamp.tv_nsec < 1000000) {
clock_id = CLOCK_MONOTONIC_COARSE;
} else if (clock_getres(CLOCK_MONOTONIC, NULL) == 0) {
clock_id = CLOCK_MONOTONIC;
} else {
fprintf(stderr, "No clock to use\n");
goto cleanup;
}
/* Create the log sink */
grc = tlog_sink_create(&sink, writer, fqdn, passwd->pw_name,
session_id, BUF_SIZE);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed creating log sink: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
/* Get terminal attributes */
rc = tcgetattr(STDOUT_FILENO, &orig_termios);
if (rc < 0) {
fprintf(stderr, "Failed retrieving tty attributes: %s\n",
strerror(errno));
goto cleanup;
}
/* Get terminal window size */
rc = ioctl(STDOUT_FILENO, TIOCGWINSZ, &winsize);
if (rc < 0) {
fprintf(stderr, "Failed retrieving tty window size: %s\n",
strerror(errno));
goto cleanup;
}
/* Fork a child under a slave pty */
child_pid = forkpty(&master_fd, NULL, &orig_termios, &winsize);
if (child_pid < 0) {
fprintf(stderr, "Failed forking a pty: %s\n", strerror(errno));
goto cleanup;
} else if (child_pid == 0) {
/*
* Child
*/
execl("/bin/bash", "/bin/bash", NULL);
fprintf(stderr, "Failed to execute the shell: %s",
strerror(errno));
goto cleanup;
}
/*
* Parent
*/
/* Log initial window size */
clock_gettime(clock_id, ×tamp);
tlog_pkt_init_window(&pkt, ×tamp,
winsize.ws_col, winsize.ws_row);
grc = tlog_sink_write(sink, &pkt);
tlog_pkt_cleanup(&pkt);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed logging window size: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
/* Setup signal handlers to terminate gracefully */
for (i = 0; i < ARRAY_SIZE(exit_sig); i++) {
sigaction(exit_sig[i], NULL, &sa);
if (sa.sa_handler != SIG_IGN)
{
sa.sa_handler = exit_sighandler;
sigemptyset(&sa.sa_mask);
for (j = 0; j < ARRAY_SIZE(exit_sig); j++)
sigaddset(&sa.sa_mask, exit_sig[j]);
/* NOTE: no SA_RESTART on purpose */
sa.sa_flags = 0;
sigaction(exit_sig[i], &sa, NULL);
}
}
/* Setup WINCH signal handler */
sa.sa_handler = winch_sighandler;
sigemptyset(&sa.sa_mask);
/* NOTE: no SA_RESTART on purpose */
sa.sa_flags = 0;
sigaction(SIGWINCH, &sa, NULL);
/* Setup ALRM signal handler */
sa.sa_handler = alarm_sighandler;
sigemptyset(&sa.sa_mask);
/* NOTE: no SA_RESTART on purpose */
sa.sa_flags = 0;
sigaction(SIGALRM, &sa, NULL);
/* Switch the terminal to raw mode */
raw_termios = orig_termios;
raw_termios.c_lflag &= ~(ICANON | ISIG | IEXTEN | ECHO);
raw_termios.c_iflag &= ~(BRKINT | ICRNL | IGNBRK | IGNCR | INLCR |
INPCK | ISTRIP | IXON | PARMRK);
raw_termios.c_oflag &= ~OPOST;
raw_termios.c_cc[VMIN] = 1;
raw_termios.c_cc[VTIME] = 0;
rc = tcsetattr(STDOUT_FILENO, TCSAFLUSH, &raw_termios);
if (rc < 0) {
fprintf(stderr, "Failed setting tty attributes: %s\n",
strerror(errno));
goto cleanup;
}
term_attrs_set = true;
/*
* Transfer I/O and window changes
*/
fds[FD_IDX_STDIN].fd = STDIN_FILENO;
fds[FD_IDX_STDIN].events = POLLIN;
fds[FD_IDX_MASTER].fd = master_fd;
fds[FD_IDX_MASTER].events = POLLIN;
while (exit_signum == 0) {
/*
* Handle SIGWINCH
*/
new_sigwinch_caught = sigwinch_caught;
if (new_sigwinch_caught != last_sigwinch_caught) {
/* Retrieve window size */
rc = ioctl(STDOUT_FILENO, TIOCGWINSZ, &new_winsize);
if (rc < 0) {
if (errno == EBADF)
status = 0;
else
fprintf(stderr, "Failed retrieving window size: %s\n",
strerror(errno));
break;
}
/* If window size has changed */
if (new_winsize.ws_row != winsize.ws_row ||
new_winsize.ws_col != winsize.ws_col) {
/* Log window size */
clock_gettime(clock_id, ×tamp);
tlog_pkt_init_window(&pkt, ×tamp,
new_winsize.ws_col,
new_winsize.ws_row);
grc = tlog_sink_write(sink, &pkt);
tlog_pkt_cleanup(&pkt);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed logging window size: %s\n",
tlog_grc_strerror(grc));
break;
}
/* Propagate window size */
rc = ioctl(master_fd, TIOCSWINSZ, &new_winsize);
if (rc < 0) {
if (errno == EBADF)
status = 0;
else
fprintf(stderr, "Failed setting window size: %s\n",
strerror(errno));
break;
}
winsize = new_winsize;
}
/* Mark SIGWINCH processed */
last_sigwinch_caught = new_sigwinch_caught;
}
/*
* Deliver I/O
*/
clock_gettime(clock_id, ×tamp);
if (input_pos < input_len) {
rc = write(master_fd, input_buf + input_pos,
input_len - input_pos);
if (rc >= 0) {
if (rc > 0) {
/* Log delivered input */
tlog_pkt_init_io(&pkt, ×tamp,
false, input_buf + input_pos,
false, (size_t)rc);
grc = tlog_sink_write(sink, &pkt);
tlog_pkt_cleanup(&pkt);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed logging input: %s\n",
tlog_grc_strerror(grc));
break;
}
io_pending = true;
input_pos += rc;
}
/* If interrupted by a signal handler */
if (input_pos < input_len)
continue;
/* Exhausted */
input_pos = input_len = 0;
} else {
if (errno == EINTR)
continue;
else if (errno == EBADF || errno == EINVAL)
status = 0;
else
fprintf(stderr, "Failed to write to master: %s\n",
strerror(errno));
break;
};
}
if (output_pos < output_len) {
rc = write(STDOUT_FILENO, output_buf + output_pos,
output_len - output_pos);
if (rc >= 0) {
if (rc > 0) {
/* Log delivered output */
tlog_pkt_init_io(&pkt, ×tamp,
true, output_buf + output_pos,
false, (size_t)rc);
grc = tlog_sink_write(sink, &pkt);
tlog_pkt_cleanup(&pkt);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed logging output: %s\n",
tlog_grc_strerror(grc));
break;
}
io_pending = true;
output_pos += rc;
}
/* If interrupted by a signal handler */
if (output_pos < output_len)
continue;
/* Exhausted */
output_pos = output_len = 0;
} else {
if (errno == EINTR)
continue;
else if (errno == EBADF || errno == EINVAL)
status = 0;
else
fprintf(stderr, "Failed to write to stdout: %s\n",
strerror(errno));
break;
};
}
/*
* Handle I/O latency limit
*/
new_alarm_caught = alarm_caught;
if (new_alarm_caught != last_alarm_caught) {
alarm_set = false;
grc = tlog_sink_flush(sink);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed flushing I/O log: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
last_alarm_caught = new_alarm_caught;
io_pending = false;
} else if (io_pending && !alarm_set) {
alarm(IO_LATENCY);
alarm_set = true;
}
/*
* Wait for I/O
*/
rc = poll(fds, sizeof(fds) / sizeof(fds[0]), -1);
if (rc < 0) {
if (errno == EINTR)
continue;
else
fprintf(stderr, "Failed waiting for I/O: %s\n",
strerror(errno));
break;
}
/*
* Retrieve I/O
*
* NOTE: Reading master first in case child went away.
* Otherwise writing to it can block
*/
if (fds[FD_IDX_MASTER].revents & (POLLIN | POLLHUP | POLLERR)) {
rc = read(master_fd, output_buf, sizeof(output_buf));
if (rc <= 0) {
if (rc < 0 && errno == EINTR)
continue;
status = 0;
break;
}
output_len = rc;
}
if (fds[FD_IDX_STDIN].revents & (POLLIN | POLLHUP | POLLERR)) {
rc = read(STDIN_FILENO, input_buf, sizeof(input_buf));
if (rc <= 0) {
if (rc < 0 && errno == EINTR)
continue;
status = 0;
break;
}
input_len = rc;
}
}
/* Cut I/O log (write incomplete characters as binary) */
grc = tlog_sink_cut(sink);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed cutting-off I/O log: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
/* Flush I/O log */
grc = tlog_sink_flush(sink);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed flushing I/O log: %s\n",
tlog_grc_strerror(grc));
goto cleanup;
}
cleanup:
tlog_sink_destroy(sink);
tlog_writer_destroy(writer);
free(fqdn);
/* Restore signal handlers */
for (i = 0; i < ARRAY_SIZE(exit_sig); i++) {
sigaction(exit_sig[i], NULL, &sa);
if (sa.sa_handler != SIG_IGN)
signal(exit_sig[i], SIG_DFL);
}
/* Restore terminal attributes */
if (term_attrs_set) {
rc = tcsetattr(STDOUT_FILENO, TCSAFLUSH, &orig_termios);
if (rc < 0 && errno != EBADF) {
fprintf(stderr, "Failed restoring tty attributes: %s\n",
strerror(errno));
return 1;
}
}
/* Reproduce the exit signal to get proper exit status */
if (exit_signum != 0)
raise(exit_signum);
return status;
}
/**
* Transfer and log terminal data until interrupted or either end closes.
*
* @param tty_source TTY data source.
* @param log_sink Log sink.
* @param tty_sink TTY data sink.
* @param latency Number of seconds to wait before flushing logged data.
* @param log_mask Logging mask with bits indexed by enum tlog_log_item.
*
* @return Global return code.
*/
static tlog_grc
transfer(struct tlog_source *tty_source,
struct tlog_sink *log_sink,
struct tlog_sink *tty_sink,
unsigned int latency,
unsigned int log_mask)
{
const int exit_sig[] = {SIGINT, SIGTERM, SIGHUP};
tlog_grc return_grc = TLOG_RC_OK;
tlog_grc grc;
size_t i, j;
struct sigaction sa;
bool alarm_set = false;
bool log_pending = false;
sig_atomic_t last_alarm_caught = 0;
sig_atomic_t new_alarm_caught;
struct tlog_pkt pkt = TLOG_PKT_VOID;
struct tlog_pkt_pos tty_pos = TLOG_PKT_POS_VOID;
struct tlog_pkt_pos log_pos = TLOG_PKT_POS_VOID;
/* Setup signal handlers to terminate gracefully */
for (i = 0; i < TLOG_ARRAY_SIZE(exit_sig); i++) {
sigaction(exit_sig[i], NULL, &sa);
if (sa.sa_handler != SIG_IGN)
{
sa.sa_handler = exit_sighandler;
sigemptyset(&sa.sa_mask);
for (j = 0; j < TLOG_ARRAY_SIZE(exit_sig); j++)
sigaddset(&sa.sa_mask, exit_sig[j]);
/* NOTE: no SA_RESTART on purpose */
sa.sa_flags = 0;
sigaction(exit_sig[i], &sa, NULL);
}
}
/* Setup ALRM signal handler */
sa.sa_handler = alarm_sighandler;
sigemptyset(&sa.sa_mask);
/* NOTE: no SA_RESTART on purpose */
sa.sa_flags = 0;
sigaction(SIGALRM, &sa, NULL);
/*
* Transfer I/O and window changes
*/
while (exit_signum == 0) {
/* Handle latency limit */
new_alarm_caught = alarm_caught;
if (new_alarm_caught != last_alarm_caught) {
alarm_set = false;
grc = tlog_sink_flush(log_sink);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed flushing log: %s\n",
tlog_grc_strerror(grc));
return_grc = grc;
goto cleanup;
}
last_alarm_caught = new_alarm_caught;
log_pending = false;
} else if (log_pending && !alarm_set) {
alarm(latency);
alarm_set = true;
}
/* Deliver logged data if any */
if (tlog_pkt_pos_cmp(&tty_pos, &log_pos) < 0) {
grc = tlog_sink_write(tty_sink, &pkt, &tty_pos, &log_pos);
if (grc != TLOG_RC_OK) {
if (grc == TLOG_GRC_FROM(errno, EINTR)) {
continue;
} else if (grc != TLOG_GRC_FROM(errno, EBADF) &&
grc != TLOG_GRC_FROM(errno, EINVAL)) {
fprintf(stderr, "Failed writing terminal data: %s\n",
tlog_grc_strerror(grc));
return_grc = grc;
}
break;
}
continue;
}
/* Log the received data, if any */
if (tlog_pkt_pos_is_in(&log_pos, &pkt)) {
/* If asked to log this type of packet */
if (log_mask & (1 << tlog_log_item_from_pkt(&pkt))) {
grc = tlog_sink_write(log_sink, &pkt, &log_pos, NULL);
if (grc != TLOG_RC_OK &&
grc != TLOG_GRC_FROM(errno, EINTR)) {
fprintf(stderr, "Failed logging terminal data: %s\n",
tlog_grc_strerror(grc));
return_grc = grc;
goto cleanup;
}
log_pending = true;
} else {
tlog_pkt_pos_move_past(&log_pos, &pkt);
}
continue;
}
/* Read new data */
tlog_pkt_cleanup(&pkt);
log_pos = TLOG_PKT_POS_VOID;
tty_pos = TLOG_PKT_POS_VOID;
grc = tlog_source_read(tty_source, &pkt);
if (grc != TLOG_RC_OK) {
if (grc == TLOG_GRC_FROM(errno, EINTR)) {
continue;
} else if (grc != TLOG_GRC_FROM(errno, EBADF) &&
grc != TLOG_GRC_FROM(errno, EIO)) {
fprintf(stderr, "Failed reading terminal data: %s\n",
tlog_grc_strerror(grc));
return_grc = grc;
}
break;
} else if (tlog_pkt_is_void(&pkt)) {
break;
}
}
/* Cut the log (write incomplete characters as binary) */
grc = tlog_sink_cut(log_sink);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed cutting-off the log: %s\n",
tlog_grc_strerror(grc));
if (return_grc == TLOG_RC_OK) {
return_grc = grc;
}
goto cleanup;
}
/* Flush the log */
grc = tlog_sink_flush(log_sink);
if (grc != TLOG_RC_OK) {
fprintf(stderr, "Failed flushing the log: %s\n",
tlog_grc_strerror(grc));
if (return_grc == TLOG_RC_OK) {
return_grc = grc;
}
goto cleanup;
}
cleanup:
tlog_pkt_cleanup(&pkt);
/* Stop the timer */
alarm(0);
/* Restore signal handlers */
signal(SIGALRM, SIG_DFL);
for (i = 0; i < TLOG_ARRAY_SIZE(exit_sig); i++) {
sigaction(exit_sig[i], NULL, &sa);
if (sa.sa_handler != SIG_IGN)
signal(exit_sig[i], SIG_DFL);
}
return return_grc;
}
