openrc/src/rc-logger.c

/*
   rc-logger.c
   Spawns a logging daemon to capture stdout and stderr so we can log
   them to a buffer and/or files.
   */

/* 
 * Copyright 2007 Roy Marples
 * All rights reserved

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/wait.h>
#include <ctype.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>

#ifdef __linux__
# include <pty.h>
#else
# include <libutil.h>
#endif

#include "einfo.h"
#include "rc-logger.h"
#include "rc-misc.h"
#include "rc.h"

#define LOGFILE RC_SVCDIR "/rc.log"
#define PERMLOG "/var/log/rc.log"
#define MOVELOG "mv " LOGFILE " " PERMLOG ".$$.tmp && cat " PERMLOG \
	".$$.tmp >>" PERMLOG " 2>/dev/null && rm -f " PERMLOG ".$$.tmp"

static int signal_pipe[2] = { -1, -1 };
static int fd_stdout = -1;
static int fd_stderr = -1;
static const char *runlevel = NULL;
static bool in_escape = false;
static bool in_term = false;

static char *logbuf = NULL;
static size_t logbuf_size = 0;
static size_t logbuf_len = 0;

pid_t rc_logger_pid = -1;
int rc_logger_tty = -1;
bool rc_in_logger = false;

static void write_log (int logfd, const char *buffer, size_t bytes)
{
	const char *p = buffer;

	while ((size_t) (p - buffer) < bytes) {
		switch (*p) {
			case '\r':
				goto cont;
			case '\033':
				in_escape = true;
				in_term = false;
				goto cont;
			case '\n':
				in_escape = in_term = false;
				break;
			case '[':
				if (in_escape)
					in_term = true;
				break;
		}
		
		if (! in_escape) {
			write (logfd, p++, 1);
			continue;
		}

		if (! in_term || isalpha (*p))
			in_escape = in_term = false;
cont:
		p++;
	}
}

static void write_time (FILE *f, const char *s)
{
	time_t now = time (NULL);
	struct tm *tm = localtime (&now);

	fprintf (f, "\nrc %s logging %s at %s\n", runlevel, s, asctime (tm));
	fflush (f);
}

void rc_logger_close ()
{
	if (signal_pipe[1] > -1) {
		int sig = SIGTERM;
		write (signal_pipe[1], &sig, sizeof (sig));
		close (signal_pipe[1]);
		signal_pipe[1] = -1;
	}

	if (rc_logger_pid > 0)
		waitpid (rc_logger_pid, 0, 0);

	if (fd_stdout > -1)
		dup2 (fd_stdout, STDOUT_FILENO);
	if (fd_stderr > -1)
		dup2 (fd_stderr, STDERR_FILENO);
}

void rc_logger_open (const char *level)
{
	int slave_tty;
	struct termios tt;
	struct winsize ws;
	char *buffer;
	fd_set rset;
	int s = 0;
	size_t bytes;
	int selfd;
	int i;
	FILE *log = NULL;

	if (! isatty (STDOUT_FILENO))
		return;

	if (! rc_conf_yesno ("rc_logger"))
		return;

	if (pipe (signal_pipe) == -1)
		eerrorx ("pipe: %s", strerror (errno));
	for (i = 0; i < 2; i++)
		if ((s = fcntl (signal_pipe[i], F_GETFD, 0) == -1 ||
			 fcntl (signal_pipe[i], F_SETFD, s | FD_CLOEXEC) == -1))
			eerrorx ("fcntl: %s", strerror (errno));

	tcgetattr (STDOUT_FILENO, &tt);
	ioctl (STDOUT_FILENO, TIOCGWINSZ, &ws);

	/* /dev/pts may not be available yet */
	if (openpty (&rc_logger_tty, &slave_tty, NULL, &tt, &ws))
		return;

	rc_logger_pid = fork ();
	switch (rc_logger_pid) {
		case -1:
			eerror ("forkpty: %s", strerror (errno));
			break;
		case 0:
			rc_in_logger = true;
			close (signal_pipe[1]);
			signal_pipe[1] = -1;

			runlevel = level;
			if ((log = fopen (LOGFILE, "a")))
				write_time (log, "started");
			else {
				free (logbuf);
				logbuf_size = RC_LINEBUFFER * 10;
				logbuf = xmalloc (sizeof (char) * logbuf_size);
				logbuf_len = 0;
			}

			buffer = xmalloc (sizeof (char) * RC_LINEBUFFER);
			selfd = rc_logger_tty > signal_pipe[0] ? rc_logger_tty : signal_pipe[0];
			while (1) {
				FD_ZERO (&rset);
				FD_SET (rc_logger_tty, &rset);
				FD_SET (signal_pipe[0], &rset);

				if ((s = select (selfd + 1, &rset, NULL, NULL, NULL)) == -1) {
					eerror ("select: %s", strerror (errno));
					break;
				}

				if (s > 0) {
					if (FD_ISSET (rc_logger_tty, &rset)) {
						memset (buffer, 0, RC_LINEBUFFER);
						bytes = read (rc_logger_tty, buffer, RC_LINEBUFFER);
						write (STDOUT_FILENO, buffer, bytes);

						if (log)
							write_log (fileno (log), buffer, bytes);
						else {
							if (logbuf_size - logbuf_len < bytes) {
								logbuf_size += RC_LINEBUFFER * 10;
								logbuf = xrealloc (logbuf, sizeof (char ) *
												   logbuf_size);
							}

							memcpy (logbuf + logbuf_len, buffer, bytes);
							logbuf_len += bytes;
						}
					}

					/* Only SIGTERMS signals come down this pipe */
					if (FD_ISSET (signal_pipe[0], &rset))
						break;
				}
			}
			free (buffer);
			if (logbuf) { 
				if ((log = fopen (LOGFILE, "a"))) {
					write_time (log, "started");
					write_log (fileno (log), logbuf, logbuf_len);
				}
				free (logbuf);
			}
			if (log) {
				write_time (log, "stopped");
				fclose (log);
			}

			/* Try and cat our new logfile to a more permament location and then
			 * punt it */
			system (MOVELOG);
			
			exit (0);
		default:
			setpgid (rc_logger_pid, 0);
			fd_stdout = dup (STDOUT_FILENO);
			fd_stderr = dup (STDERR_FILENO);
			dup2 (slave_tty, STDOUT_FILENO);
			dup2 (slave_tty, STDERR_FILENO);
			if (slave_tty != STDIN_FILENO &&
				slave_tty != STDOUT_FILENO &&
				slave_tty != STDERR_FILENO)
				close (slave_tty);
			close (signal_pipe[0]);
			signal_pipe[0] = -1;
			break;
	}
}