gen/common/syslog.c

/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * 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 <sys/signal.h>
#include <sys/syslog.h>
#include <sys/time.h>
#include <sys/unistd.h>
#include <netdb.h>
#include <strings.h>
#include <stdarg.h>
#include <vfork.h>
#include <stdio.h>
#include <errno.h>
#include <malloc.h>


#define MAXLINE 1024            /* max message size */

#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 char *sysmsg = "/dev/sysmsg";

static struct _syslog {
    int _LogFile;
    int _LogStat;
    char    *_LogTag;
    int _LogMask;
    struct  sockaddr _SyslogAddr;
    char    *_SyslogHost;
    int _LogFacility;
} *_syslog;
#define LogFile (_syslog->_LogFile)
#define LogStat (_syslog->_LogStat)
#define LogTag (_syslog->_LogTag)
#define LogMask (_syslog->_LogMask)
#define SyslogAddr (_syslog->_SyslogAddr)
#define SyslogHost (_syslog->_SyslogHost)
#define LogFacility (_syslog->_LogFacility)


extern char *strerror(int);
extern time_t time();

void    vsyslog(int, char *, va_list);
void    openlog(char *, int, int);
static int  snprintf(char *, size_t, char *, ...);
static int  vsnprintf(char *, size_t, char *, va_list ap);

static int
allocstatic(void)
{
    _syslog = (struct _syslog *)calloc(1, sizeof (struct _syslog));
    if (_syslog == 0)
        return (0); /* can't do it */
    LogFile = -1;       /* fd for log */
    LogStat = 0;        /* status bits, set by openlog() */
    LogTag = "syslog";  /* string to tag the entry with */
    LogMask = 0xff;     /* mask of priorities to be logged */
    LogFacility = LOG_USER; /* default facility code */
    return (1);
}

void
syslog(int pri, char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    vsyslog(pri, fmt, ap);
    va_end(ap);
}

void
vsyslog(int pri, char *fmt, va_list ap)
{
    char buf[MAXLINE + 1], outline[MAXLINE + 1];
    char *b, *f, *o;
    int c;
    long now;
    int pid, olderrno = errno;
    int retsiz, outsiz = MAXLINE + 1;
    int taglen;
/*
 * Maximum tag length is 256 (the pad in outline) minus the size of the
 * other things that can go in the pad.
 */
#define MAX_TAG 230


    if (_syslog == 0 && !allocstatic())
        return;

    /* 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_NDELAY, 0);

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

    /* build the message */
    o = outline;
    (void) time(&now);
    (void) sprintf(o, "<%d>%.15s ", pri, ctime(&now) + 4);
    o += strlen(o);

    if (LogTag) {
        taglen = strlen(LogTag) < MAX_TAG ? strlen(LogTag) : MAX_TAG;
        strncpy(o, LogTag, taglen);
        o[taglen] = '\0';
        o += strlen(o);
    }
    if (LogStat & LOG_PID) {
        (void) sprintf(o, "[%d]", getpid());
        o += strlen(o);
    }
    if (LogTag) {
        (void) strcpy(o, ": ");
        o += 2;
    }

    b = buf;
    f = fmt;
    while ((c = *f++) != '\0' && c != '\n' && b < &buf[MAXLINE]) {
        char *errstr;

        if (c != '%') {
            *b++ = c;
            continue;
        }
        if ((c = *f++) != 'm') {
            *b++ = '%';
            *b++ = c;
            continue;
        }
        if ((errstr = strerror(olderrno)) == NULL)
            (void) snprintf(b, &buf[MAXLINE] - b, "error %d",
                olderrno);
        else {
            while (*errstr != '\0' && b < &buf[MAXLINE]) {
                if (*errstr == '%') {
                    strcpy(b, "%%");
                    b += 2;
                }
                else
                    *b++ = *errstr;
                errstr++;
            }
            *b = '\0';
        }
        b += strlen(b);
    }
    if (b > buf && *(b-1) != '\n')  /* ensure at least one newline */
        *b++ = '\n';
    *b = '\0';
    (void) vsnprintf(o, &outline[sizeof (outline)] - o, buf, ap);
    c = strlen(outline) + 1;    /* add one for NULL byte */
    if (c > MAXLINE) {
        c = MAXLINE;
        outline[MAXLINE-1] = '\0';
    }

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

    /* output the message to the console */
    pid = vfork();
    if (pid == -1)
        return;
    if (pid == 0) {
        int fd;

        (void) signal(SIGALRM, SIG_DFL);
        (void) sigsetmask(sigblock(0) & ~sigmask(SIGALRM));
        (void) alarm(5);
        if (((fd = open(sysmsg, O_WRONLY)) >= 0) ||
            (fd = open(ctty, O_WRONLY)) >= 0) {
            (void) alarm(0);
            if (outsiz > 2) {   /* Just in case */
                (void) strcat(o, "\r\n");
                c += 2;
            }
            o = index(outline, '>') + 1;
            (void) write(fd, o, c - (o - outline));
            (void) close(fd);
        } else
            (void) alarm(0);
        _exit(0);
    }
    if (!(LogStat & LOG_NOWAIT))
        while ((c = wait((int *)0)) > 0 && c != pid)
            ;
}

/*
 * OPENLOG -- open system log
 */
void
openlog(char *ident, int logstat, int logfac)
{
    if (_syslog == 0 && !allocstatic())
        return;
    if (ident != NULL)
        LogTag = ident;
    LogStat = logstat;
    if (logfac != 0)
        LogFacility = logfac & LOG_FACMASK;
    if (LogFile >= 0)
        return;
    SyslogAddr.sa_family = AF_UNIX;
    (void) strncpy(SyslogAddr.sa_data, logname,
        sizeof (SyslogAddr.sa_data));
    if (LogStat & LOG_NDELAY) {
        LogFile = socket(AF_UNIX, SOCK_DGRAM, 0);
        (void) fcntl(LogFile, F_SETFD, 1);
    }
}

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

    if (_syslog == 0)
        return;
    (void) close(LogFile);
    LogFile = -1;
}

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

    if (_syslog == 0 && !allocstatic())
        return (-1);
    omask = LogMask;
    if (pmask != 0)
        LogMask = pmask;
    return (omask);
}

/*
 * snprintf/vsnprintf -- These routines are here
 * temporarily to solve bugid 1220257. Perhaps
 * they could become a public interface at some
 * point but not for now.
 */

extern int _doprnt();

static int
snprintf(char *string, size_t n, char *format, ...)
{
    int count;
    FILE siop;
    va_list ap;

    if (n == 0)
        return (0);
    siop._cnt = n - 1;
    siop._base = siop._ptr = (unsigned char *)string;
    siop._flag = _IOWRT+_IOSTRG;
    va_start(ap, format);
    count = _doprnt(format, ap, &siop);
    va_end(ap);
    *siop._ptr = '\0';  /* plant terminating null character */
    return (count);
}

static int
vsnprintf(char *string, size_t n, char *format, va_list ap)
{
    int count;
    FILE siop;

    if (n == 0)
        return (0);
    siop._cnt = n - 1;
    siop._base = siop._ptr = (unsigned char *)string;
    siop._flag = _IOWRT+_IOSTRG;
    count = _doprnt(format, ap, &siop);
    *siop._ptr = '\0';  /* plant terminating null character */
    return (count);
}