From 5c236a2c2082525aac6ec3c7cf95e25110d5a52e Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 22 Sep 2014 02:00:50 +0100
Subject: [PATCH] logging: Provide lg_perror and lg_vperror

These are convenience functions for logging module, config location,
errno value, etc., along with a full formatted message.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 log.c    | 36 ++++++++++++++++++++++++++++++++++++
 secnet.h | 11 +++++++++++
 2 files changed, 47 insertions(+)

diff --git a/log.c b/log.c
index 6dbf25a..156f354 100644
--- a/log.c
+++ b/log.c
@@ -189,6 +189,42 @@ static void log_vmulti(void *sst, int class, const char *message, va_list args)
     }
 }
 
+void lg_vperror(struct log_if *lg, const char *desc, struct cloc *loc,
+		int class, int errnoval, const char *fmt, va_list al)
+{
+    int status=current_phase;
+    int esave=errno;
+
+    if (!lg)
+	lg=system_log;
+
+    if (class & M_FATAL)
+	enter_phase(PHASE_SHUTDOWN);
+
+    slilog_part(lg,class,"%s",desc);
+    if (loc)
+	slilog_part(lg,class," (%s:%d)",loc->file,loc->line);
+    slilog_part(lg,class,": ");
+    vslilog_part(lg,class,fmt,al);
+    if (errnoval)
+	slilog_part(lg,class,": %s",strerror(errnoval));
+    slilog_part(lg,class,"\n");
+
+    if (class & M_FATAL)
+	exit(status);
+
+    errno=esave;
+}
+
+void lg_perror(struct log_if *lg, const char *desc, struct cloc *loc,
+	       int class, int errnoval, const char *fmt, ...)
+{
+    va_list al;
+    va_start(al,fmt);
+    lg_vperror(lg,desc,loc,class,errnoval,fmt,al);
+    va_end(al);
+}
+
 struct log_if *init_log(list_t *ll)
 {
     int i=0;
diff --git a/secnet.h b/secnet.h
index 72e3e7c..f4a33cb 100644
--- a/secnet.h
+++ b/secnet.h
@@ -579,6 +579,17 @@ extern NORETURN(fatal_status(int status, const char *message, ...))
 extern NORETURN(fatal_perror_status(int status, const char *message, ...))
        FORMAT(printf,2,3);
 
+/* Convenient nonfatal logging.  Requires message that does not end in '\n'.
+ * If class contains M_FATAL, exits (after entering PHASE_SHUTDOWN).
+ * lg, errnoval and loc may sensibly be 0.  desc must NOT be 0.
+ * lg_[v]perror save and restore errno. */
+void lg_vperror(struct log_if *lg, const char *desc, struct cloc *loc,
+		int class, int errnoval, const char *fmt, va_list al)
+    FORMAT(printf,6,0);
+void lg_perror(struct log_if *lg, const char *desc, struct cloc *loc,
+	       int class, int errnoval, const char *fmt, ...)
+    FORMAT(printf,6,7);
+
 /* The cfgfatal() family of functions require messages that end in '\n' */
 extern NORETURN(cfgfatal(struct cloc loc, cstring_t facility,
 			 const char *message, ...)) FORMAT(printf,3,4);
-- 
2.30.2