Re: [PATCH 2/6] conf, log: Introduce internal log flags, instead of abusing log levels

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jun 17, 2024 at 02:03:15PM +0200, Stefano Brivio wrote:
> We currently use a LOG_EMERG log mask to represent the fact that we
> don't know yet what the mask resulting from configuration should be,
> before the command line is parsed.
> 
> However, we have the necessity of representing another phase as well,
> that is, configuration is parsed but we didn't daemonise yet, or
> we're not ready for operation yet. The next patch will add that
> notion explicitly.
> 
> Mapping these cases to further log levels isn't really practical.
> Introduce internal log flags to represent them, instead of abusing
> log priorities.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

I like not abusing the log priorities.  But, do we actually need a
flags field with constants and helpers, rather than just
	bool log_conf_parsed;
and open code it from there?

> ---
>  conf.c |  5 ++---
>  log.c  | 18 +++++++++++++-----
>  log.h  |  4 ++++
>  3 files changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/conf.c b/conf.c
> index dbdbb62..0b76da9 100644
> --- a/conf.c
> +++ b/conf.c
> @@ -1701,9 +1701,6 @@ void conf(struct ctx *c, int argc, char **argv)
>  			     logfile, logsize);
>  	}
>  
> -	/* Once the log mask is not LOG_EARLY, we will no longer log to stderr
> -	 * if there was a log file specified.
> -	 */
>  	if (c->debug)
>  		__setlogmask(LOG_UPTO(LOG_DEBUG));
>  	else if (c->quiet)
> @@ -1711,6 +1708,8 @@ void conf(struct ctx *c, int argc, char **argv)
>  	else
>  		__setlogmask(LOG_UPTO(LOG_INFO));
>  
> +	log_set_flag(LOG_FLAG_CONF_PARSED);	/* Stop printing everything */
> +
>  	nl_sock_init(c, false);
>  	if (!v6_only)
>  		c->ifi4 = conf_ip4(ifi4, &c->ip4, c->mac);
> diff --git a/log.c b/log.c
> index aaf2beb..3b5a1c6 100644
> --- a/log.c
> +++ b/log.c
> @@ -30,14 +30,13 @@
>  #include "util.h"
>  #include "passt.h"
>  
> -/* LOG_EARLY means we don't know yet: log everything. LOG_EMERG is unused */
> -#define LOG_EARLY		LOG_MASK(LOG_EMERG)
> -
>  static int	log_sock = -1;		/* Optional socket to system logger */
>  static char	log_ident[BUFSIZ];	/* Identifier string for openlog() */
> -static int	log_mask = LOG_EARLY;	/* Current log priority mask */
> +static int	log_mask;		/* Current log priority mask */
>  static int	log_opt;		/* Options for openlog() */
>  
> +static uint8_t	log_flags;		/* Internal, see LOG_FLAG_* in log.h */
> +
>  static int	log_file = -1;		/* Optional log file descriptor */
>  static size_t	log_size;		/* Maximum log file size in bytes */
>  static size_t	log_written;		/* Currently used bytes in log file */
> @@ -50,7 +49,7 @@ int		log_trace;		/* --trace mode enabled */
>  void vlogmsg(int pri, const char *format, va_list ap)
>  {
>  	bool debug_print = (log_mask & LOG_MASK(LOG_DEBUG)) && log_file == -1;
> -	bool early_print = LOG_PRI(log_mask) == LOG_EARLY;
> +	bool early_print = !(log_flags & LOG_FLAG_CONF_PARSED);
>  	struct timespec tp;
>  
>  	if (debug_print) {
> @@ -150,6 +149,15 @@ void __setlogmask(int mask)
>  	setlogmask(mask);
>  }
>  
> +/**
> + * log_set_flag() - Set an internal log flag
> + * @flag:	Flag as defined by LOG_FLAG_* in log.h
> + */
> +void log_set_flag(uint8_t flag)
> +{
> +	log_flags |= flag;
> +}
> +
>  /**
>   * passt_vsyslog() - vsyslog() implementation not using heap memory
>   * @pri:	Facility and level map, same as priority for vsyslog()
> diff --git a/log.h b/log.h
> index e0aab5a..6a3224a 100644
> --- a/log.h
> +++ b/log.h
> @@ -6,8 +6,11 @@
>  #ifndef LOG_H
>  #define LOG_H
>  
> +#include <stdint.h>
>  #include <syslog.h>
>  
> +#define LOG_FLAG_CONF_PARSED	BIT(0)	/* We already parsed logging options */
> +
>  #define LOGFILE_SIZE_DEFAULT		(1024 * 1024UL)
>  #define LOGFILE_CUT_RATIO		30	/* When full, cut ~30% size */
>  #define LOGFILE_SIZE_MIN		(5UL * MAX(BUFSIZ, PAGE_SIZE))
> @@ -40,5 +43,6 @@ void logfile_init(const char *name, const char *path, size_t size);
>  void passt_vsyslog(int pri, const char *format, va_list ap);
>  void logfile_write(int pri, const char *format, va_list ap);
>  void __setlogmask(int mask);
> +void log_set_flag(uint8_t flag);
>  
>  #endif /* LOG_H */

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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