audit: add actual audit log I/O functions (ref #88)

Makefile.am

@@ -57,6 +57,7 @@ EXTRA_DIST =	\
 
 pkginclude_HEADERS = libpkgconf/bsdstubs.h libpkgconf/iter.h libpkgconf/libpkgconf.h libpkgconf/stdinc.h
 libpkgconf_la_SOURCES  =	\
+		libpkgconf/audit.c		\
 		libpkgconf/cache.c		\
 		libpkgconf/pkg.c		\
 		libpkgconf/bsdstubs.c		\

libpkgconf/audit.c

@@ -0,0 +1,34 @@
+/*
+ * audit.c
+ * package audit log functions
+ *
+ * Copyright (c) 2016 pkgconf authors (see AUTHORS).
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <libpkgconf/libpkgconf.h>
+
+static FILE *pkgconf_auditf = NULL;
+
+void
+pkgconf_audit_open_log(FILE *auditf)
+{
+	pkgconf_auditf = auditf;
+}
+
+void
+pkgconf_audit_log(const char *format, ...)
+{
+	va_list va;
+
+	va_start(va, format);
+	vfprintf(pkgconf_auditf, format, va);
+	va_end(va);
+}

libpkgconf/libpkgconf.h

@@ -206,4 +206,8 @@ void pkgconf_cache_add(pkgconf_pkg_t *pkg);
 void pkgconf_cache_remove(pkgconf_pkg_t *pkg);
 void pkgconf_cache_free(void);
 
+/* audit.c */
+void pkgconf_audit_open_log(FILE *auditf);
+void pkgconf_audit_log(const char *format, ...) PRINTFLIKE(1, 2);
+
 #endif

main.c

@@ -782,7 +782,10 @@ main(int argc, char *argv[])
 		logfile_arg = getenv("PKG_CONFIG_LOG");
 
 	if (logfile_arg != NULL)
+	{
 		logfile_out = fopen(logfile_arg, "w");
+		pkgconf_audit_open_log(logfile_out);
+	}
 
 	if (required_module_version != NULL)
 	{