usr/src/lib/libc/gen/syslog.c

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char sccsid[] = "@(#)syslog.c    5.2 (Berkeley) %G%";
#endif not lint

/*
 * SYSLOG -- print message on log file
 *
 * This routine looks a lot like printf, except that it
 * outputs to the log file instead of the standard output.
 * Also:
 *      adds a timestamp,
 *      prints the module name in front of the message,
 *      has some other formatting types (or will sometime),
 *      adds a newline on the end of the message.
 *
 * The output of this routine is intended to be read by /etc/syslogd.
 *
 * Author: Eric Allman
 * Modified to use UNIX domain IPC by Ralph Campbell
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <syslog.h>
#include <netdb.h>

#define MAXLINE 1024                    /* max message size */
#define NULL    0                       /* manifest */

#define PRIMASK(p)      (1 << ((p) & LOG_PRIMASK))
#define PRIFAC(p)       (((p) & LOG_FACMASK) >> 3)
#define IMPORTANT       LOG_ERR

static char     logname[] = "/dev/log";
static char     ctty[] = "/dev/console";

static int      LogFile = -1;           /* fd for log */
static int      LogStat = 0;            /* status bits, set by openlog() */
static char     *LogTag = "syslog";     /* string to tag the entry with */
static int      LogMask = 0xff;         /* mask of priorities to be logged */
static int      LogFacility = LOG_USER; /* default facility code */

static struct sockaddr SyslogAddr;      /* AF_UNIX address of local logger */

extern  int errno, sys_nerr;
extern  char *sys_errlist[];

syslog(pri, fmt, p0, p1, p2, p3, p4)
        int pri;
        char *fmt;
{
        char buf[MAXLINE + 1], outline[MAXLINE + 1];
        register char *b, *f, *o;
        register int c;
        long now;
        int pid, olderrno = errno;

        /* see if we should just throw out this message */
        if (pri <= 0 || PRIFAC(pri) >= LOG_NFACILITIES || (PRIMASK(pri) & LogMask) == 0)
                return;
        if (LogFile < 0)
                openlog(LogTag, LogStat & ~LOG_ODELAY, 0);

        /* set default facility if none specified */
        if ((pri & LOG_FACMASK) == 0)
                pri |= LogFacility;

        /* build the message */
        o = outline;
        sprintf(o, "<%d>", pri);
        o += strlen(o);
        time(&now);
        sprintf(o, "%.15s ", ctime(&now) + 4);
        o += strlen(o);
        if (LogTag) {
                strcpy(o, LogTag);
                o += strlen(o);
        }
        if (LogStat & LOG_PID) {
                sprintf(o, "[%d]", getpid());
                o += strlen(o);
        }
        if (LogTag) {
                strcpy(o, ": ");
                o += 2;
        }

        b = buf;
        f = fmt;
        while ((c = *f++) != '\0' && c != '\n' && b < &buf[MAXLINE]) {
                if (c != '%') {
                        *b++ = c;
                        continue;
                }
                if ((c = *f++) != 'm') {
                        *b++ = '%';
                        *b++ = c;
                        continue;
                }
                if ((unsigned)olderrno > sys_nerr)
                        sprintf(b, "error %d", olderrno);
                else
                        strcpy(b, sys_errlist[olderrno]);
                b += strlen(b);
        }
        *b++ = '\n';
        *b = '\0';
        sprintf(o, buf, p0, p1, p2, p3, p4);
        c = strlen(outline);
        if (c > MAXLINE)
                c = MAXLINE;

        /* output the message to the local logger */
        if (sendto(LogFile, outline, c, 0, &SyslogAddr, sizeof SyslogAddr) >= 0)
                return;
        if (!(LogStat & LOG_CONS) && (pri & LOG_PRIMASK) <= LOG_ERR)
                return;

        /* output the message to the console */
        pid = fork();
        if (pid == -1)
                return;
        if (pid == 0) {
                LogFile = open(ctty, O_WRONLY);
                strcat(o, "\r");
                write(LogFile, outline, c+1);
                close(LogFile);
                exit(0);
        }
        while ((c = wait((int *)0)) > 0 && c != pid)
                ;
}

/*
 * OPENLOG -- open system log
 */

openlog(ident, logstat, logfac)
        char *ident;
        int logstat, logfac;
{
        if (ident != NULL)
                LogTag = ident;
        LogStat = logstat;
        if (logfac != 0)
                LogFacility = logfac & LOG_FACMASK;
        if (LogFile >= 0)
                return;
        SyslogAddr.sa_family = AF_UNIX;
        strncpy(SyslogAddr.sa_data, logname, sizeof SyslogAddr.sa_data);
        if (!(LogStat & LOG_ODELAY)) {
                LogFile = socket(AF_UNIX, SOCK_DGRAM, 0);
                fcntl(LogFile, F_SETFD, 1);
        }
}

/*
 * CLOSELOG -- close the system log
 */
closelog()
{

        (void) close(LogFile);
        LogFile = -1;
}

/*
 * SETLOGMASK -- set the log mask level
 */
setlogmask(pmask)
        int pmask;
{
        int omask;

        omask = LogMask;
        if (pmask != 0)
                LogMask = pmask;
        return (omask);
}