syslogd.c

压缩包中包含LINUX下多个命令的源码

/* syslogd - log system messages
 *
 * Copyright (c) 1983, 1988, 1993, 1994, 2002
 *	The Regents of the University of California.  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.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#if 0
static char sccsid[] = "@(#)syslogd.c	8.3 (Berkeley) 4/4/94";
#endif

/*
 *  syslogd -- log system messages
 *
 * This program implements a system log. It takes a series of lines.
 * Each line may have a priority, signified as "<n>" as the first
 * characters of the line.  If this is not present, a default priority
 * is used.
 *
 * To kill syslogd, send a signal 15 (terminate).  A signal 1 (hup)
 * will cause it to reread its configuration file.
 *
 * Defined Constants:
 *
 * MAXLINE -- the maximum line length that can be handled.
 * DEFUPRI -- the default priority for user messages
 * DEFSPRI -- the default priority for kernel messages
 *
 * Author: Eric Allman
 * extensive changes by Ralph Campbell
 * more extensive changes by Eric Allman (again)
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#define IOVCNT          6               /* size of the iovec array */
#define	MAXLINE		1024		/* Maximum line length.  */
#define	MAXSVLINE	240		/* Maximum saved line length.  */
#define DEFUPRI		(LOG_USER|LOG_NOTICE)
#define DEFSPRI		(LOG_KERN|LOG_CRIT)
#define TIMERINTVL	30		/* Interval for checking flush, mark.  */
#define TTYMSGTIME      10              /* Time out passed to ttymsg.  */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>
#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#include <sys/resource.h>
#include <poll.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif

#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>

#ifdef HAVE_UTMP_H
# include <utmp.h>
#endif

#ifdef UTMPX
# ifdef HAVE_UTMPX_H
#  include <utmpx.h>
# endif
typedef struct utmpx UTMP;
# define SETUTENT() setutxent()
# define GETUTENT() getutxent()
# define ENDUTENT() endutxent()
#else
typedef struct utmp UTMP;
# define SETUTENT() setutent()
# define GETUTENT() getutent()
# define ENDUTENT() endutent()
#endif

#ifdef HAVE_STDARG_H
# include <stdarg.h>
#else
# include <varargs.h>
#endif

#define SYSLOG_NAMES
#include <syslog.h>
#ifndef HAVE_SYSLOG_INTERNAL
# include <syslog-int.h>
#endif

const char *ConfFile = PATH_LOGCONF; /* Default Configuration file.  */
const char *PidFile = PATH_LOGPID; /* Default path to tuck pid.  */
char ctty[] = PATH_CONSOLE; /* Default console to send message info.  */

static int dbg_output;   /* If true, print debug output in debug mode.  */
static int restart;  /* If 1, indicates SIGHUP was dropped.  */

/* Unix socket family to listen.  */
struct funix
{
  const char *name;
  int fd;
} *funix;

size_t nfunix; /* Number of unix sockets in the funix array.  */

/*
 * Flags to logmsg().
 */

#define IGN_CONS	0x001	/* Don't print on console.  */
#define SYNC_FILE	0x002	/* Do fsync on file after printing.  */
#define ADDDATE		0x004	/* Add a date to the message.  */
#define MARK		0x008	/* This message is a mark.  */

/* This structure represents the files that will have log copies
   printed.  */

struct filed
{
  struct filed *f_next;			/* Next in linked list.  */
  short f_type;				/* Entry type, see below.  */
  short f_file;				/* File descriptor.  */
  time_t f_time;			/* Time this was last written.  */
  u_char f_pmask[LOG_NFACILITIES+1];	/* Priority mask.  */
  union
  {
    struct
    {
      int f_nusers;
      char **f_unames;
    } f_user;                           /* Send a message to a user.  */
    struct
    {
      char *f_hname;
      struct sockaddr_in f_addr;
    } f_forw;				/* Forwarding address.  */
    char *f_fname;                      /* Name use for Files|Pipes|TTYs.  */
  } f_un;
  char f_prevline[MAXSVLINE];		/* Last message logged.  */
  char f_lasttime[16];			/* Time of last occurrence.  */
  char *f_prevhost;			/* Host from which recd.  */
  int f_prevpri;			/* Pri of f_prevline.  */
  int f_prevlen;			/* Length of f_prevline.  */
  int f_prevcount;			/* Repetition cnt of prevline.  */
  size_t f_repeatcount;			/* Number of "repeated" msgs.  */
  int f_flags;				/* Additional flags see below.  */
};

struct filed *Files;	/* Linked list of files to log to.  */
struct filed consfile;	/* Console `file'.  */

/* Values for f_type.  */
#define F_UNUSED	0	/* Unused entry.  */
#define F_FILE		1	/* Regular file.  */
#define F_TTY		2	/* Terminal.  */
#define F_CONSOLE	3	/* Console terminal.  */
#define F_FORW		4	/* Remote machine.  */
#define F_USERS		5	/* List of users.  */
#define F_WALL		6	/* Everyone logged on.  */
#define F_FORW_SUSP	7	/* Suspended host forwarding.  */
#define F_FORW_UNKN	8	/* Unknown host forwarding.  */
#define F_PIPE		9	/* Named pipe.  */

const char *TypeNames[] =
{
  "UNUSED",
  "FILE",
  "TTY",
  "CONSOLE",
  "FORW",
  "USERS",
  "WALL",
  "FORW(SUSPENDED)",
  "FORW(UNKNOWN)",
  "PIPE"
};

/* Flags in filed.f_flags.  */
#define OMIT_SYNC	0x001   /* Omit fsync after printing.  */

/* Constants for the F_FORW_UNKN retry feature.  */
#define INET_SUSPEND_TIME 180	/* Number of seconds between attempts.  */
#define INET_RETRY_MAX	10	/* Number of times to try gethostbyname().  */

/* Intervals at which we flush out "message repeated" messages, in
 seconds after previous message is logged.  After each flush, we move
 to the next interval until we reach the largest.  */

int repeatinterval[] = { 30, 60 };	/* Number of seconds before flush.  */
#define	MAXREPEAT ((sizeof(repeatinterval) / sizeof(repeatinterval[0])) - 1)
#define	REPEATTIME(f)	((f)->f_time + repeatinterval[(f)->f_repeatcount])
#define	BACKOFF(f)	{ if (++(f)->f_repeatcount > MAXREPEAT) \
				 (f)->f_repeatcount = MAXREPEAT; \
			}

/* Delimiter in arguments to command line options `-s' and `-l'.  */
#define LIST_DELIMITER	':'

char *LocalHostName;            /* Our hostname.  */
char *LocalDomain;              /* Our local domain name.  */
int finet = -1;                 /* Internet datagram socket fd.  */
int fklog = -1;                 /* Kernel log device fd.  */
int LogPort;                    /* Port number for INET connections.  */
int Initialized;                /* True when we are initialized. */
int MarkInterval = 20 * 60;     /* Interval between marks in seconds.  */
int MarkSeq;                    /* Mark sequence number.  */

int Debug;                      /* True if in debug mode.  */
int AcceptRemote;               /* Receive messages that come via UDP.  */
char **StripDomains;            /* Domains to be stripped before logging.  */
char **LocalHosts;              /* Hosts to be logged by their hostname.  */
int NoDetach;                   /* Don't run in background and detach
				   from ctty. */
int NoHops = 1;	                /* Bounce syslog messages for other hosts.  */
int NoKLog;                     /* Don't attempt to log kernel device.  */
int NoUnixAF;                   /* Don't listen to unix sockets. */
int NoForward;                  /* Don't forward messages.  */
time_t  now;                    /* Time use for mark and forward supending.  */
int force_sync;                 /* GNU/Linux behaviour to sync on every line.
				   This off by default. Set to 1 to enable.  */

extern char *localhost __P ((void));
extern int waitdaemon __P ((int nochdir, int noclose, int maxwait));
extern char *__progname;

void cfline __P ((const char *, struct filed *));
const char *cvthname __P ((struct sockaddr_in *));
int decode __P ((const char *, CODE *));
void die __P ((int));
void domark __P ((int));
void fprintlog __P ((struct filed *, const char *, int, const char *));
void init __P ((int));
void logerror __P ((const char *));
void logmsg __P ((int, const char *, const char *, int));
void printline __P ((const char *, const char *));
void printsys __P ((const char *));
char *ttymsg __P ((struct iovec *, int, char *, int));
static void usage __P ((int));
void wallmsg __P ((struct filed *, struct iovec *));
char **crunch_list __P ((char **oldlist, char *list));
char *textpri __P ((int pri));
void dbg_toggle __P ((int));
static void dbg_printf __P ((const char *, ...));
void trigger_restart __P ((int));
static void add_funix __P ((const char *path));
static int create_unix_socket __P ((const char *path));
static int create_inet_socket __P ((void));

static void
usage (int err)
{
  if (err != 0)
    {
      fprintf (stderr, "Usage: %s [OPTION] ...\n", __progname);
      fprintf (stderr, "Try `%s --help' for more information.\n", __progname);
    }
  else
    {
      fprintf (stdout, "Usage: %s [OPTION] ...\n", __progname);
      puts ("Log system messages.\n\n\
  -f, --rcfile=FILE  Override configuration file (default: " PATH_LOGCONF ")\n\
      --pidfile=FILE Override pidfile (default: " PATH_LOGPID ")\n\
  -n, --no-detach    Don't enter daemon mode\n\
  -d, --debug        Print debug information (implies -n)\n\
  -p, --socket FILE  Override default unix domain socket " PATH_LOG "\n\
  -a SOCKET          Add unix socket to listen to (up to 19)\n\
  -r, --inet         Receive remote messages via internet domain socket\n\
      --no-unixaf    Do not listen on unix domain sockets (overrides -a and -p)\n\
  -S, --sync         Force a file sync on every line");
#ifdef PATH_KLOG
      puts ("\
      --no-klog      Do not listen to kernel log device " PATH_KLOG);
#endif
      puts ("\
      --no-forward   Do not forward any messages (overrides -h)\n\
  -h, --hop          Forward messages from remote hosts\n\
  -m, --mark=INTVL   Specify timestamp interval in logs (0 for no timestamps)\n\
  -l HOSTLIST        Log hosts in HOSTLIST by their hostname\n\
  -s DOMAINLIST      List of domains which should be stripped from the FQDN\n\
                     of hosts before logging their name.\n\
      --help         Display this help and exit\n\
  -V, --version      Output version information and exit");

      fprintf (stdout, "\nSubmit bug reports to %s.\n", PACKAGE_BUGREPORT);
    }
  exit (err);
}

static const char *short_options = "a:dhf:l:m:np:rs:VS";
static struct option long_options[] =
{
  { "debug", no_argument, 0, 'd' },
  { "rcfile", required_argument, 0, 'f' },
  { "pidfile", required_argument, 0, 'P' },
  { "hop", no_argument, 0, 'h' },
  { "mark", required_argument, 0, 'm' },
  { "no-detach", no_argument, 0, 'n' },
  { "socket", required_argument, 0, 'p' },
  { "inet", no_argument, 0, 'r' },
  { "no-klog", no_argument, 0, 'K' },
  { "no-forward", no_argument, 0, 'F' },
  { "no-unixaf", no_argument, 0, 'U' },
  { "sync", no_argument, 0, 'S' },
  { "help", no_argument, 0, '&' },
  { "version", no_argument, 0, 'V' },
#if 0 /* Not sure about the long name. Maybe move into conffile even.  */
  { "", required_argument, 0, 'a' },
  { "", required_argument, 0, 's' },
  { "", required_argument, 0, 'l' },
#endif
  { 0, 0, 0, 0 }
};

int
main (int argc, char *argv[])
{
  int option;
  size_t i;
  FILE *fp;
  char *p;
  char line[MAXLINE + 1];
  char kline[MAXLINE + 1];
  int kline_len = 0;
  pid_t ppid = 0;	/* We run in debug mode and didn't fork.  */
  struct pollfd *fdarray;
  unsigned long nfds = 0;

#ifndef HAVE___PROGNAME
  __progname = argv[0];
#endif

  /* Initiliaze PATH_LOG as the first element of the unix sockets array.  */
  add_funix (PATH_LOG);

  while ((option = getopt_long (argc, argv, short_options,
				long_options, 0)) != EOF)
    {
      switch(option)
	{
	case 'a': /* Add to unix socket array.  */
	  add_funix (optarg);
	  break;

	case 'd': /* Debug mode.  */
	  Debug = 1;
	  NoDetach = 1;
	  break;

	case 'f': /* Override the default config file.  */
	  ConfFile = optarg;
	  break;

	case 'h': /* Disable forwarding.  */
	  NoHops = 0;
	  break;

	case 'l': /* Add host to be log whithout the FQDN.  */
	  LocalHosts = crunch_list (LocalHosts, optarg);
	  break;

	case 'm': /* Set the timestamp interval mark.  */
	  MarkInterval = atoi (optarg) * 60;
	  break;

	case 'n': /* Don't run in background.  */
	  NoDetach = 1;
	  break;

	case 'p': /* Overide PATH_LOG name.  */
	  funix[0].name = optarg;
	  funix[0].fd = -1;
	  break;

	case 'r': /* Enable remote message via inet socket.  */
	  AcceptRemote = 1;
	  break;

	case 's': /* List of domain names to strip.  */
	  StripDomains = crunch_list (StripDomains, optarg);
	  break;

	case 'P': /* Override pidfile.  */
	  PidFile = optarg;
	  break;

	case 'K': /* Disable kernel logging.  */
	  NoKLog = 1;
	  break;

	case 'F': /* Disable forwarding.  */
	  NoForward = 1;
	  break;

	case 'U': /* Disable  unix sockets.  */
	  NoUnixAF = 1;
	  break;

	case 'S': /* Sync on every line.  */
	  force_sync = 1;
	  break;

	case '&': /* Usage.  */
	  usage (0);
	  /* Not reached.  */

	case 'V': /* Version.  */
	  printf ("syslogd (%s) %s\n", PACKAGE_NAME, PACKAGE_VERSION);
	  exit (0);

	case '?':
	default:
	  usage (1);
	  /* Not reached.  */
	}
    }

  /* Bail out, wrong usage */
  argc -= optind;
  if (argc != 0)
    usage (1);

  /* Daemonise, if not, set the buffering for line buffer.  */
  if (!NoDetach)
    {
      /* History:  According to the GNU/Linux sysklogd ChangeLogs
	 "Wed Feb 14 12:42:09 CST 1996:  Dr. Wettstein
	 Parent process of syslogd does not exit until child process has
	 finished initialization process.  This allows rc.* startup to
	 pause until syslogd facility is up and operating."

	 IMO, the GNU/Linux distributors should fix there booting
	 sequence. But we still keep the approach.  */
      ppid = waitdaemon (0, 0, 30);
      if (ppid < 0)
	{
	  fprintf (stderr, "%s: could not become daemon: %s\n",
		   __progname, strerror (errno));
	  exit (1);
	}
    }
  else
    {
      dbg_output = 1;
      setvbuf (stdout, 0, _IOLBF, 0);
    }

  /* Get our hostname.  */
  LocalHostName = localhost ();
  if (LocalHostName == NULL)
    {
      fprintf (stderr, "%s: can't get local host name: %s\n",
	       __progname, strerror (errno));
      exit (2);
    }
  /* Get the domainname.  */
  p = strchr (LocalHostName, '.');
  if (p != NULL)
    {
      *p++ = '\0';
      LocalDomain = p;
    }
  else
    {
      struct hostent *host_ent;