[PATCH] sysklogd: add -Z option to adjust message timezones

[walter harms]

Since this is a musl (only ?) feature i would suggest
to make that selectable.

re,
 wh

Am 08.05.2017 23:45, schrieb Shiz:
> Some syslog() implementations like musl's[1] always send timestamps in UTC.
> This change adds a new option to syslogd, -Z, to assume incoming timestamps
> are always UTC and adjust them to the local timezone (of the syslogd) before
> logging.
> 
> [1]: http://www.openwall.com/lists/musl/2014/01/29/1
> 
> Signed-off-by: Shiz <hi at shiz.me>
> ---
>  sysklogd/syslogd.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/sysklogd/syslogd.c b/sysklogd/syslogd.c
> index d64ff27..159336e 100644
> --- a/sysklogd/syslogd.c
> +++ b/sysklogd/syslogd.c
> @@ -122,6 +122,7 @@
>  //usage:       "(this version of syslogd ignores /etc/syslog.conf)\n"
>  //usage:	)
>  //usage:     "\n	-n		Run in foreground"
> +//usage:     "\n	-Z		Adjust incoming UTC times to local time"
>  //usage:	IF_FEATURE_REMOTE_LOG(
>  //usage:     "\n	-R HOST[:PORT]	Log to HOST:PORT (default PORT:514)"
>  //usage:     "\n	-L		Log locally and via network (default is network only if -R)"
> @@ -233,6 +234,8 @@ typedef struct logRule_t {
>  	/*int markInterval;*/                   \
>  	/* level of messages to be logged */    \
>  	int logLevel;                           \
> +	/* whether to adjust message timezone */\
> +	int adjustTimezone;                     \
>  IF_FEATURE_ROTATE_LOGFILE( \
>  	/* max size of file before rotation */  \
>  	unsigned logFileSize;                   \
> @@ -316,6 +319,7 @@ enum {
>  	OPTBIT_outfile, // -O
>  	OPTBIT_loglevel, // -l
>  	OPTBIT_small, // -S
> +	OPTBIT_adjusttz, // -Z
>  	IF_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,)	// -s
>  	IF_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,)	// -b
>  	IF_FEATURE_REMOTE_LOG(    OPTBIT_remotelog  ,)	// -R
> @@ -330,6 +334,7 @@ enum {
>  	OPT_outfile     = 1 << OPTBIT_outfile ,
>  	OPT_loglevel    = 1 << OPTBIT_loglevel,
>  	OPT_small       = 1 << OPTBIT_small   ,
> +	OPT_adjusttz    = 1 << OPTBIT_adjusttz,
>  	OPT_filesize    = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
>  	OPT_rotatecnt   = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
>  	OPT_remotelog   = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remotelog  )) + 0,
> @@ -339,7 +344,7 @@ enum {
>  	OPT_cfg         = IF_FEATURE_SYSLOGD_CFG(   (1 << OPTBIT_cfg        )) + 0,
>  	OPT_kmsg        = IF_FEATURE_KMSG_SYSLOG(   (1 << OPTBIT_kmsg       )) + 0,
>  };
> -#define OPTION_STR "m:nO:l:S" \
> +#define OPTION_STR "m:nO:l:SZ" \
>  	IF_FEATURE_ROTATE_LOGFILE("s:" ) \
>  	IF_FEATURE_ROTATE_LOGFILE("b:" ) \
>  	IF_FEATURE_REMOTE_LOG(    "R:*") \
> @@ -815,17 +820,23 @@ static void timestamp_and_log(int pri, char *msg, int len)
>  {
>  	char *timestamp;
>  	time_t now;
> +	struct tm nowtm = { .tm_isdst = 0 };
why ? is there a bug ?

>  
>  	/* Jan 18 00:11:22 msg... */
>  	/* 01234567890123456 */
>  	if (len < 16 || msg[3] != ' ' || msg[6] != ' '
>  	 || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
>  	) {
> -		time(&now);
> +		now = time(NULL);

is the same

>  		timestamp = ctime(&now) + 4; /* skip day of week */
>  	} else {
> -		now = 0;
> -		timestamp = msg;
> +		if (G.adjustTimezone && strptime(msg, "%b %e %T", &nowtm)) {
> +			now = mktime(&nowtm) - timezone;
> +			timestamp = ctime(&now) + 4; /* skip day of week */
> +		} else {
> +			now = 0;
> +			timestamp = msg;
> +		}

It is more easy to disable the feature if you do
		now = 0;
		timestamp = msg;
		if (G.adjustTimezone && strptime(msg, "%b %e %T", &nowtm)) {
			now = mktime(&nowtm) - timezone;
			timestamp = ctime(&now) + 4; /* skip day of week */
		}


just my 2 cents,

re,
 wh


>  		msg += 16;
>  	}
>  	timestamp[15] = '\0';
> @@ -1130,6 +1141,10 @@ int syslogd_main(int argc UNUSED_PARAM, char **argv)
>  	if (opts & OPT_loglevel) // -l
>  		G.logLevel = xatou_range(opt_l, 1, 8);
>  	//if (opts & OPT_small) // -S
> +	if (opts & OPT_adjusttz) { // -Z
> +		G.adjustTimezone = 1;
> +		tzset();
> +	}
>  #if ENABLE_FEATURE_ROTATE_LOGFILE
>  	if (opts & OPT_filesize) // -s
>  		G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;