MINOR: diag: create cfgdiag module

This module is intended to serve as a placeholder for various
diagnostics executed after the configuration file has been fully loaded.

Makefile

@@ -878,7 +878,7 @@ OBJS += src/mux_h2.o src/mux_fcgi.o src/http_ana.o src/stream.o                \
         src/ebistree.o src/auth.o src/wdt.o src/http_acl.o                     \
         src/hpack-enc.o src/hpack-huff.o src/ebtree.o src/base64.o             \
         src/hash.o src/dgram.o src/version.o src/fix.o src/mqtt.o src/dns.o    \
-        src/server_state.o src/proto_uxdg.o src/init.o
+        src/server_state.o src/proto_uxdg.o src/init.o src/cfgdiag.o
 
 ifneq ($(TRACE),)
 OBJS += src/calltrace.o

include/haproxy/cfgdiag.h

@@ -0,0 +1,11 @@
+#ifndef _HAPROXY_CFGDIAG_H
+#define _HAPROXY_CFGDIAG_H
+
+/* Placeholder to execute various diagnostic checks after the configuration file
+ * has been fully parsed. It will output a warning for each diagnostic found.
+ *
+ * Returns 0 if no diagnostic message has been found else 1.
+ */
+int cfg_run_diagnostics();
+
+#endif /* _HAPROXY_CFGDIAG_H */

src/cfgdiag.c

@@ -0,0 +1,45 @@
+#include <stdarg.h>
+#include <stdlib.h>
+
+#include <haproxy/cfgdiag.h>
+#include <haproxy/log.h>
+
+/* Use this fonction to emit diagnostic.
+ * This can be used as a shortcut to set value pointed by <ret> to 1 at the
+ * same time.
+ */
+static inline void diag_warning(int *ret, char *fmt, ...)
+{
+	va_list argp;
+
+	va_start(argp, fmt);
+	*ret = 1;
+	_ha_vdiag_warning(fmt, argp);
+	va_end(argp);
+}
+
+/* Use this for dynamic allocation in diagnostics.
+ * In case of allocation failure, this will immediately terminates haproxy.
+ */
+static inline void *diag_alloc(size_t size)
+{
+	void *out = NULL;
+
+	if (!(out = malloc(size))) {
+		fprintf(stderr, "out of memory\n");
+		exit(1);
+	}
+
+	return out;
+}
+
+/* Placeholder to execute various diagnostic checks after the configuration file
+ * has been fully parsed. It will output a warning for each diagnostic found.
+ *
+ * Returns 0 if no diagnostic message has been found else 1.
+ */
+int cfg_run_diagnostics()
+{
+	int ret = 0;
+	return ret;
+}

src/haproxy.c

@@ -87,6 +87,7 @@
 #include <haproxy/auth.h>
 #include <haproxy/base64.h>
 #include <haproxy/capture-t.h>
+#include <haproxy/cfgdiag.h>
 #include <haproxy/cfgparse.h>
 #include <haproxy/chunk.h>
 #include <haproxy/cli.h>
@@ -1806,6 +1807,10 @@ static void init(int argc, char **argv)
 		exit(2);
 	}
 
+	if (global.mode & MODE_DIAG) {
+		cfg_run_diagnostics();
+	}
+
 	/* now we know the buffer size, we can initialize the channels and buffers */
 	init_buffer();