[PATCH] dix: adding timestamps to the server logs.

[Alan Coopersmith]

localtime() & strftime() are not safe to call from signal handlers.
Perhaps we should have special log functions to call from signal handlers
instead of reusing, and thus limiting, the main ones - but until that happens,
we need to stick to async-signal-safe functions in the log routines.

-- 
	-Alan Coopersmith-           alan.coopersmith at sun.com
	 Sun Microsystems, Inc. - X Window System Engineering

Bhaskar Tilak wrote:
> This patch prepends a timestamp to each line of the X log file.
> Hopefully, this is helpful in diagnosing user problems, and correlating
> between events in the X log and system log.
> 
> Here is an example snippet of the X log with timestamps prepended:
> 
>  Aug 31 16:08:47 (II) Loading extension XFree86-VidModeExtension
>  Aug 31 16:08:47 (II) Loading extension DPMS
>  Aug 31 16:08:47 (II) Loading extension XVideo
>  Aug 31 16:08:47 (II) Loading extension XVideo-MotionCompensation
> 
> This patch enables timestamps by default, and provides a "-notimestamps"
> commandline option to disable timestamps.
> ---
>  dix/globals.c       |    5 +++++
>  doc/Xserver.man.pre |    4 ++++
>  include/globals.h   |    1 +
>  os/log.c            |   30 ++++++++++++++++++++++++------
>  os/utils.c          |    5 +++++
>  5 files changed, 39 insertions(+), 6 deletions(-)
> 
> diff --git a/dix/globals.c b/dix/globals.c
> index c24a94f..49a0819 100644
> --- a/dix/globals.c
> +++ b/dix/globals.c
> @@ -139,3 +139,8 @@ char *ConnectionInfo;
>  CARD32 TimeOutValue = DEFAULT_TIMEOUT * MILLI_PER_SECOND;
>  
>  DDXPointRec dixScreenOrigins[MAXSCREENS];
> +
> +/* Timestamping support for X logs. By default, timestamping in X logs is on.
> + * Use command line option '-notimestamps'  to turn it off.
> + */
> +Bool logTimestamps = TRUE;
> diff --git a/doc/Xserver.man.pre b/doc/Xserver.man.pre
> index 6154191..699fd15 100644
> --- a/doc/Xserver.man.pre
> +++ b/doc/Xserver.man.pre
> @@ -197,6 +197,10 @@ overrides a previous
>  .B \-terminate
>  command line option.
>  .TP 8
> +.B \-notimestamps
> +Disable the time stamps in the X log file.
> +By default, the server adds the time stamps to the X log file.
> +.TP 8
>  .B \-p \fIminutes\fP
>  sets screen-saver pattern cycle time in minutes.
>  .TP 8
> diff --git a/include/globals.h b/include/globals.h
> index 52c19a4..779f994 100644
> --- a/include/globals.h
> +++ b/include/globals.h
> @@ -26,6 +26,7 @@ extern _X_EXPORT Bool noTestExtensions;
>  extern _X_EXPORT DDXPointRec dixScreenOrigins[MAXSCREENS];
>  
>  extern _X_EXPORT char *ConnectionInfo;
> +extern _X_EXPORT Bool logTimestamps;
>  
>  #ifdef DPMSExtension
>  extern _X_EXPORT CARD32 DPMSStandbyTime;
> diff --git a/os/log.c b/os/log.c
> index 8108890..47364bb 100644
> --- a/os/log.c
> +++ b/os/log.c
> @@ -316,7 +316,10 @@ void
>  LogVMessageVerb(MessageType type, int verb, const char *format, va_list args)
>  {
>      const char *s  = X_UNKNOWN_STRING;
> -    char tmpBuf[1024];
> +    char tmpBuf[1024], timestampBuf[32];
> +    time_t rawtime;
> +    struct tm *timeinfo = NULL;
> +    int timeFault = 0;
>  
>      /* Ignore verbosity for X_ERROR */
>      if (logVerbosity >= verb || logFileVerbosity >= verb || type == X_ERROR) {
> @@ -358,11 +361,26 @@ LogVMessageVerb(MessageType type, int verb, const char *format, va_list args)
>  	    break;
>  	}
>  
> -        /* if s is not NULL we need a space before format */
> -        snprintf(tmpBuf, sizeof(tmpBuf), "%s%s%s", s ? s : "",
> -                                                   s ? " " : "",
> -                                                   format);
> -        LogVWrite(verb, tmpBuf, args);
> +	if (!logTimestamps || (-1 == time(&rawtime))) {
> +	    timeFault = 1;
> +	} else {
> +	    if (NULL == (timeinfo = localtime(&rawtime)))
> +	        timeFault = 1;
> +	}
> +
> +	if (timeFault || !strftime(timestampBuf, sizeof(timestampBuf),
> +	                           "%b %d %X ", timeinfo))
> +	    timestampBuf[0] = '\0';
> +
> +	/* being extra cautious with string management */
> +	timestampBuf[31] = '\0';
> +
> +	/* if s is not NULL we need a space before format */
> +	snprintf(tmpBuf, sizeof(tmpBuf), "%s%s%s%s", timestampBuf,
> +	                                             s ? s : "",
> +	                                             s ? " " : "",
> +	                                             format);
> +	LogVWrite(verb, tmpBuf, args);
>      }
>  }
>  
> diff --git a/os/utils.c b/os/utils.c
> index 3718b17..eeb9781 100644
> --- a/os/utils.c
> +++ b/os/utils.c
> @@ -511,6 +511,7 @@ void UseMsg(void)
>      ErrorF("-logo                  enable logo in screen saver\n");
>      ErrorF("nologo                 disable logo in screen saver\n");
>  #endif
> +    ErrorF("-notimestamps          disable the timestamps in X log file\n");
>      ErrorF("-nolisten string       don't listen on protocol\n");
>      ErrorF("-noreset               don't reset after last client exists\n");
>      ErrorF("-reset                 reset after last client exists\n");
> @@ -960,6 +961,10 @@ ProcessCommandLine(int argc, char *argv[])
>  	    else
>  		UseMsg();
>  	}
> +	else if ( strcmp( argv[i], "-notimestamps") == 0)
> +	{
> +	    logTimestamps = FALSE;
> +	}
>   	else
>   	{
>  	    ErrorF("Unrecognized option: %s\n", argv[i]);