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

/*
 * Copyright (c) 1983, 1988, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)syslog.c    8.1 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

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

#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

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

/*
 * syslog, vsyslog --
 *      print message on log file; output is intended for syslogd(8).
 */
void
#if __STDC__
syslog(int pri, const char *fmt, ...)
#else
syslog(pri, fmt, va_alist)
        int pri;
        char *fmt;
        va_dcl
#endif
{
        va_list ap;

#if __STDC__
        va_start(ap, fmt);
#else
        va_start(ap);
#endif
        vsyslog(pri, fmt, ap);
        va_end(ap);
}

void
vsyslog(pri, fmt, ap)
        int pri;
        register const char *fmt;
        va_list ap;
{
        register int cnt;
        register char *p;
        time_t now;
        int fd, saved_errno;
        char *stdp, tbuf[2048], fmt_cpy[1024];

#define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
        /* Check for invalid bits. */
        if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
                syslog(INTERNALLOG,
                    "syslog: unknown facility/priority: %x", pri);
                pri &= LOG_PRIMASK|LOG_FACMASK;
        }

        /* Check priority against setlogmask values. */
        if (!LOG_MASK(LOG_PRI(pri)) & LogMask)
                return;

        saved_errno = errno;

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

        /* build the message */
        (void)time(&now);
        (void)sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
        for (p = tbuf; *p; ++p);
        if (LogStat & LOG_PERROR)
                stdp = p;
        if (LogTag) {
                (void)strcpy(p, LogTag);
                for (; *p; ++p);
        }
        if (LogStat & LOG_PID) {
                (void)sprintf(p, "[%d]", getpid());
                for (; *p; ++p);
        }
        if (LogTag) {
                *p++ = ':';
                *p++ = ' ';
        }

        /* substitute error message for %m */
        {
                register char ch, *t1, *t2;
                char *strerror();

                for (t1 = fmt_cpy; ch = *fmt; ++fmt)
                        if (ch == '%' && fmt[1] == 'm') {
                                ++fmt;
                                for (t2 = strerror(saved_errno);
                                    *t1 = *t2++; ++t1);
                        }
                        else
                                *t1++ = ch;
                *t1 = '\0';
        }

        (void)vsprintf(p, fmt_cpy, ap);

        cnt = strlen(tbuf);

        /* output to stderr if requested */
        if (LogStat & LOG_PERROR) {
                struct iovec iov[2];
                register struct iovec *v = iov;

                v->iov_base = stdp;
                v->iov_len = cnt - (stdp - tbuf);
                ++v;
                v->iov_base = "\n";
                v->iov_len = 1;
                (void)writev(STDERR_FILENO, iov, 2);
        }

        /* get connected, output the message to the local logger */
        if (!connected)
                openlog(LogTag, LogStat | LOG_NDELAY, 0);
        if (send(LogFile, tbuf, cnt, 0) >= 0)
                return;

        /* see if should attempt the console */
        if (!(LogStat&LOG_CONS))
                return;

        /*
         * Output the message to the console; don't worry about blocking,
         * if console blocks everything will.  Make sure the error reported
         * is the one from the syslogd failure.
         */
        if ((fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
                (void)strcat(tbuf, "\r\n");
                cnt += 2;
                p = index(tbuf, '>') + 1;
                (void)write(fd, p, cnt - (p - tbuf));
                (void)close(fd);
        }
}

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

void
openlog(ident, logstat, logfac)
        const char *ident;
        int logstat, logfac;
{
        if (ident != NULL)
                LogTag = ident;
        LogStat = logstat;
        if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
                LogFacility = logfac;

        if (LogFile == -1) {
                SyslogAddr.sa_family = AF_UNIX;
                (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
                    sizeof(SyslogAddr.sa_data));
                if (LogStat & LOG_NDELAY) {
                        if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
                                return;
                        (void)fcntl(LogFile, F_SETFD, 1);
                }
        }
        if (LogFile != -1 && !connected)
                if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) == -1) {
                        (void)close(LogFile);
                        LogFile = -1;
                } else
                        connected = 1;
}

void
closelog()
{
        (void)close(LogFile);
        LogFile = -1;
        connected = 0;
}

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

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