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

13 Feb 2023

On Mon, 13 Feb 2023 14:22:33 +1100
David Gibson  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  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 
---
 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

    