klogd.c

制作2.6内核的CLFS时 sysklogd-1.5.tar.gz包

	int sig;

{
	Terminate();
	return;
}


void reload_daemon(sig)

     int sig;

{
	change_state = 1;
	reload_symbols = 1;


	if ( sig == SIGUSR2 )
	{
		++reload_symbols;
		signal(SIGUSR2, reload_daemon);
	}
	else
		signal(SIGUSR1, reload_daemon);
		
	return;
}


static void Terminate()

{
	CloseLogSrc();
	Syslog(LOG_INFO, "Kernel log daemon terminating.");
	sleep(1);
	if ( output_file != (FILE *) 0 )
		fclose(output_file);
	closelog();
#ifndef TESTING
	(void) remove_pid(PidFile);
#endif
	exit(1);
}

static void SignalDaemon(sig)

     int sig;

{
#ifndef TESTING
	auto int pid = check_pid(PidFile);

	kill(pid, sig);
#else
	kill(getpid(), sig);
#endif
	return;
}


static void ReloadSymbols()

{
	if (symbol_lookup) {
		if ( reload_symbols > 1 )
			InitKsyms(symfile);
		InitMsyms();
	}
	reload_symbols = change_state = 0;
	return;
}


static void ChangeLogging(void)

{
	/* Terminate kernel logging. */
	if ( terminate == 1 )
		Terminate();

	/* Indicate that something is happening. */
	Syslog(LOG_INFO, "klogd %s.%s, ---------- state change ----------\n", \
	       VERSION, PATCHLEVEL);

	/* Reload symbols. */
	if ( reload_symbols > 0 )
	{
		ReloadSymbols();
		return;
	}

	/* Stop kernel logging. */
	if ( caught_TSTP == 1 )
	{
		CloseLogSrc();
		logsrc = none;
		change_state = 0;
		return;
	}
		
	/*
	 * The rest of this function is responsible for restarting
	 * kernel logging after it was stopped.
	 *
	 * In the following section we make a decision based on the
	 * kernel log state as to what is causing us to restart.  Somewhat
	 * groady but it keeps us from creating another static variable.
	 */
	if ( logsrc != none )
	{
		Syslog(LOG_INFO, "Kernel logging re-started after SIGSTOP.");
		change_state = 0;
		return;
	}

	/* Restart logging. */
	logsrc = GetKernelLogSrc();
	change_state = 0;
	return;
}


static enum LOGSRC GetKernelLogSrc(void)

{
	auto struct stat sb;


	/* Set level of kernel console messaging.. */
	if ( (console_log_level != -1)
	&& (ksyslog(8, NULL, console_log_level) < 0) && \
	     (errno == EINVAL) )
	{
		/*
		 * An invalid arguement error probably indicates that
		 * a pre-0.14 kernel is being run.  At this point we
		 * issue an error message and simply shut-off console
		 * logging completely.
		 */
		Syslog(LOG_WARNING, "Cannot set console log level - disabling "
		       "console output.");
	}

	/*
	 * First do a stat to determine whether or not the proc based
	 * file system is available to get kernel messages from.
	 */
	if ( use_syscall ||
	    ((stat(_PATH_KLOG, &sb) < 0) && (errno == ENOENT)) )
	{
	  	/* Initialize kernel logging. */
	  	ksyslog(1, NULL, 0);
#ifdef DEBRELEASE
		Syslog(LOG_INFO, "klogd %s.%s#%s, log source = ksyslog "
		       "started.", VERSION, PATCHLEVEL, DEBRELEASE);
#else
		Syslog(LOG_INFO, "klogd %s.%s, log source = ksyslog "
		       "started.", VERSION, PATCHLEVEL);
#endif
		return(kernel);
	}

#ifndef TESTING
	if ( (kmsg = open(_PATH_KLOG, O_RDONLY)) < 0 )
	{
		fprintf(stderr, "klogd: Cannot open proc file system, " \
			"%d - %s.\n", errno, strerror(errno));
		ksyslog(7, NULL, 0);
		exit(1);
	}
#else
	kmsg = fileno(stdin);
#endif

#ifdef DEBRELEASE
	Syslog(LOG_INFO, "klogd %s.%s#%s, log source = %s started.", \
	       VERSION, PATCHLEVEL, DEBRELEASE, _PATH_KLOG);
#else
	Syslog(LOG_INFO, "klogd %s.%s, log source = %s started.", \
	       VERSION, PATCHLEVEL, _PATH_KLOG);
#endif
	return(proc);
}


extern void Syslog(int priority, char *fmt, ...)

{
	va_list ap;
	char *argl;

	if ( debugging )
	{
		fputs("Logging line:\n", stderr);
		fprintf(stderr, "\tLine: %s\n", fmt);
		fprintf(stderr, "\tPriority: %d\n", priority);
	}

	/* Handle output to a file. */
	if ( output_file != (FILE *) 0 )
	{
		va_start(ap, fmt);
		vfprintf(output_file, fmt, ap);
		va_end(ap);
		fputc('\n', output_file);
		fflush(output_file);
		if (!one_shot)
			fsync(fileno(output_file));
		return;
	}
	
	/* Output using syslog. */
	if (!strcmp(fmt, "%s"))
	{
		va_start(ap, fmt);
		argl = va_arg(ap, char *);
		if (argl[0] == '<' && argl[1] && argl[2] == '>')
		{
			switch ( argl[1] )
			{
			case '0':
				priority = LOG_EMERG;
				break;
			case '1':
				priority = LOG_ALERT;
				break;
			case '2':
				priority = LOG_CRIT;
				break;
			case '3':
				priority = LOG_ERR;
				break;
			case '4':
				priority = LOG_WARNING;
				break;
			case '5':
				priority = LOG_NOTICE;
				break;
			case '6':
				priority = LOG_INFO;
				break;
			case '7':
			default:
				priority = LOG_DEBUG;
			}
			argl += 3;
		}
		syslog(priority, fmt, argl);
		va_end(ap);
#ifdef TESTING
		putchar('\n');
#endif
		return;
	}

	va_start(ap, fmt);
	vsyslog(priority, fmt, ap);
	va_end(ap);
#ifdef TESTING
	printf ("\n");
#endif

	return;
}


/*
 *     Copy characters from ptr to line until a char in the delim
 *     string is encountered or until min( space, len ) chars have
 *     been copied.
 *
 *     Returns the actual number of chars copied.
 */
static int copyin( char *line,      int space,
                   const char *ptr, int len,
                   const char *delim )
{
    auto int i;
    auto int count;

    count = len < space ? len : space;

    for(i=0; i<count && !strchr(delim, *ptr); i++ ) { *line++ = *ptr++; }

    return( i );
}

/*
 * Messages are separated by "\n".  Messages longer than
 * LOG_LINE_LENGTH are broken up.
 *
 * Kernel symbols show up in the input buffer as : "[<aaaaaa>]",
 * where "aaaaaa" is the address.  These are replaced with
 * "[symbolname+offset/size]" in the output line - symbolname,
 * offset, and size come from the kernel symbol table.
 *
 * If a kernel symbol happens to fall at the end of a message close
 * in length to LOG_LINE_LENGTH, the symbol will not be expanded.
 * (This should never happen, since the kernel should never generate
 * messages that long.
 *
 * To preserve the original addresses, lines containing kernel symbols
 * are output twice.  Once with the symbols converted and again with the
 * original text.  Just in case somebody wants to run their own Oops
 * analysis on the syslog, e.g. ksymoops.
 */
static void LogLine(char *ptr, int len)
{
    enum parse_state_enum {
        PARSING_TEXT,
        PARSING_SYMSTART,      /* at < */
        PARSING_SYMBOL,        
        PARSING_SYMEND         /* at ] */
    };

    static char line_buff[LOG_LINE_LENGTH];

    static char *line                        =line_buff;
    static enum parse_state_enum parse_state = PARSING_TEXT;
    static int space                         = sizeof(line_buff)-1;

    static char *sym_start;            /* points at the '<' of a symbol */

    auto   int delta = 0;              /* number of chars copied        */
    auto   int symbols_expanded = 0;   /* 1 if symbols were expanded */
    auto   int skip_symbol_lookup = 0; /* skip symbol lookup on this pass */
    auto   char *save_ptr = ptr;       /* save start of input line */
    auto   int save_len = len;         /* save length at start of input line */

    while( len > 0 )
    {
        if( space == 0 )    /* line buffer is full */
        {
            /*
            ** Line too long.  Start a new line.
            */
            *line = 0;   /* force null terminator */

	    if ( debugging )
	    {
		fputs("Line buffer full:\n", stderr);
		fprintf(stderr, "\tLine: %s\n", line);
	    }

            Syslog( LOG_INFO, "%s", line_buff );
            line  = line_buff;
            space = sizeof(line_buff)-1;
            parse_state = PARSING_TEXT;
	    symbols_expanded = 0;
	    skip_symbol_lookup = 0;
	    save_ptr = ptr;
	    save_len = len;
        }

        switch( parse_state )
        {
        case PARSING_TEXT:
               delta = copyin( line, space, ptr, len, "\n[" );
               line  += delta;
               ptr   += delta;
               space -= delta;
               len   -= delta;

               if( space == 0 || len == 0 )
               {
		  break;  /* full line_buff or end of input buffer */
               }

               if( *ptr == '\0' )  /* zero byte */
               {
                  ptr++;	/* skip zero byte */
                  space -= 1;
                  len   -= 1;

		  break;
	       }

               if( *ptr == '\n' )  /* newline */
               {
                  ptr++;	/* skip newline */
                  space -= 1;
                  len   -= 1;

                  *line = 0;  /* force null terminator */
	          Syslog( LOG_INFO, "%s", line_buff );
                  line  = line_buff;
                  space = sizeof(line_buff)-1;
		  if (symbols_twice) {
		      if (symbols_expanded) {
			  /* reprint this line without symbol lookup */
			  symbols_expanded = 0;
			  skip_symbol_lookup = 1;
			  ptr = save_ptr;
			  len = save_len;
		      }
		      else
		      {
			  skip_symbol_lookup = 0;
			  save_ptr = ptr;
			  save_len = len;
		      }
		  }