Re: [PATCH v2 2/9] add errexit() to log an error message and exit with a single call

[Stefano Brivio <sbrivio@redhat.com>]

On Mon, 13 Feb 2023 14:22:33 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Thu, Feb 09, 2023 at 06:45:32PM +0100, Stefano Brivio wrote:
> > On Wed,  8 Feb 2023 12:48:31 -0500
> > Laine Stump <laine@redhat.com> wrote:
> >   
> > > Almost all occurences of err() are either immediately followed by
> > > exit(EXIT_FAILURE), usage(argv[0]) (which itself then calls
> > > exit(EXIT_FAILURE), or that is what's done immediately after returning
> > > from the function that calls err(). Modify the errfn macro so that its
> > > instantiations can include exit(EXIT_FAILURE) at the end, and use that
> > > to create a new function errxit() that will log an error and then
> > > exit.
> > > 
> > > Signed-off-by: Laine Stump <laine@redhat.com>
> > > ---
> > >  log.c | 13 ++++++++-----
> > >  log.h |  1 +
> > >  2 files changed, 9 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/log.c b/log.c
> > > index 0ab0adf..4956914 100644
> > > --- a/log.c
> > > +++ b/log.c
> > > @@ -45,7 +45,7 @@ static char	log_header[BUFSIZ];	/* File header, written back on cuts */
> > >  static time_t	log_start;		/* Start timestamp */
> > >  int		log_trace;		/* --trace mode enabled */
> > >  
> > > -#define logfn(name, level)						\
> > > +#define logfn(name, level, doexit)					\
> > >  void name(const char *format, ...) {					\
> > >  	struct timespec tp;						\
> > >  	va_list args;							\
> > > @@ -76,6 +76,8 @@ void name(const char *format, ...) {					\
> > >  		if (format[strlen(format)] != '\n')			\
> > >  			fprintf(stderr, "\n");				\
> > >  	}								\
> > > +	if (doexit)							\  
> > 
> > A blank line before this would make it more consistent.
> >   
> > > +		exit(EXIT_FAILURE);					\
> > >  }
> > >  
> > >  /* Prefixes for log file messages, indexed by priority */
> > > @@ -88,10 +90,11 @@ const char *logfile_prefix[] = {
> > >  	"         ",		/* LOG_DEBUG */
> > >  };
> > >  
> > > -logfn(err,   LOG_ERR)
> > > -logfn(warn,  LOG_WARNING)
> > > -logfn(info,  LOG_INFO)
> > > -logfn(debug, LOG_DEBUG)
> > > +logfn(errexit, LOG_ERR,     1)
> > > +logfn(err,     LOG_ERR,     0)
> > > +logfn(warn,    LOG_WARNING, 0)
> > > +logfn(info,    LOG_INFO,    0)
> > > +logfn(debug,   LOG_DEBUG,   0)
> > >  
> > >  /**
> > >   * log_go_daemon() - tell logging subsystem that the process has been
> > > diff --git a/log.h b/log.h
> > > index a57c777..ed19415 100644
> > > --- a/log.h
> > > +++ b/log.h
> > > @@ -10,6 +10,7 @@
> > >  #define LOGFILE_CUT_RATIO		30	/* When full, cut ~30% size */
> > >  #define LOGFILE_SIZE_MIN		(5UL * MAX(BUFSIZ, PAGE_SIZE))
> > >  
> > > +void errexit(const char *format, ...);
> > >  void err(const char *format, ...);
> > >  void warn(const char *format, ...);
> > >  void info(const char *format, ...);  
> > 
> > Other than that, this looks good to me.  
> 
> LGTM.  Personally I like to call such functions "die()".

I was about to suggest that (it's shorter and conveys the same meaning),
then I thought die() would be a common library function. Actually, it's
not -- so I would also favour die() here.

-- 
Stefano