From d37cd3c69781c0d77af13dec81eea45b4c434c52 Mon Sep 17 00:00:00 2001
From: Marko Kreen <markokr@gmail.com>
Date: Fri, 4 Jan 2008 07:57:01 +0000
Subject: [PATCH] proper usage of flexible array

---
 include/bouncer.h | 3 ++-
 include/sbuf.h    | 4 +++-
 include/system.h  | 9 +++++++++
 src/main.c        | 5 ++---
 src/sbuf.c        | 2 +-
 5 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/include/bouncer.h b/include/bouncer.h
index ff02358..47dfdb9 100644
--- a/include/bouncer.h
+++ b/include/bouncer.h
@@ -257,7 +257,8 @@ struct PgSocket {
 	SBuf		sbuf;		/* stream buffer, must be last */
 };
 
-#define PG_SOCKET_SIZE	(sizeof(PgSocket) + cf_sbuf_len + SBUF_MAX_REWRITE)
+#define RAW_SOCKET_SIZE offsetof(struct PgSocket, sbuf.buf)
+#define PG_SOCKET_SIZE	(RAW_SOCKET_SIZE + cf_sbuf_len + SBUF_MAX_REWRITE)
 
 /* where to store old fd info during SHOW FDS result processing */
 #define tmp_sk_oldfd	request_time
diff --git a/include/sbuf.h b/include/sbuf.h
index 18a2c74..b21e5ba 100644
--- a/include/sbuf.h
+++ b/include/sbuf.h
@@ -85,9 +85,11 @@ struct SBuf {
 
 	SBuf *dst;		/* target SBuf for current packet */
 
-	uint8_t buf[0];		/* data buffer follows (cf_sbuf_len + SBUF_MAX_REWRITE) */
+	uint8_t buf[FLEX_ARRAY];/* data buffer follows (cf_sbuf_len + SBUF_MAX_REWRITE) */
 };
 
+#define RAW_SBUF_SIZE offsetof(struct SBuf, buf)
+
 #define sbuf_socket(sbuf) ((sbuf)->sock)
 
 void sbuf_init(SBuf *sbuf, sbuf_cb_t proto_fn, void *arg);
diff --git a/include/system.h b/include/system.h
index 58568ed..0838101 100644
--- a/include/system.h
+++ b/include/system.h
@@ -56,6 +56,15 @@
 #include <crypt.h>
 #endif
 
+/* how to specify array with unknown length */
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+#define FLEX_ARRAY
+#elif defined(__GNUC__)
+#define FLEX_ARRAY
+#else
+#define FLEX_ARRAY 1
+#endif
+
 /* gcc has hew positive aspects too */
 #ifdef __GNUC__
 
diff --git a/src/main.c b/src/main.c
index 9a3d3e7..38f4773 100644
--- a/src/main.c
+++ b/src/main.c
@@ -435,9 +435,8 @@ static void check_limits(void)
 	List *item;
 	PgDatabase *db;
 
-	log_noise("event: %lu, SBuf: %lu, PgSocket: %lu, Full PgSocket: %lu, buf ofs: %lu",
-		  sizeof(struct event), sizeof(SBuf), sizeof(PgSocket),
-		  PG_SOCKET_SIZE, offsetof(SBuf, buf));
+	log_noise("event: %lu, SBuf: %lu, PgSocket: %lu, Full PgSocket: %lu",
+		  sizeof(struct event), RAW_SBUF_SIZE, RAW_SOCKET_SIZE, PG_SOCKET_SIZE);
 
 	/* load limits */
 	err = getrlimit(RLIMIT_NOFILE, &lim);
diff --git a/src/sbuf.c b/src/sbuf.c
index c1662ef..7b66739 100644
--- a/src/sbuf.c
+++ b/src/sbuf.c
@@ -71,7 +71,7 @@ static bool sbuf_after_connect_check(SBuf *sbuf)  _MUSTCHECK;
 /* initialize SBuf with proto handler */
 void sbuf_init(SBuf *sbuf, sbuf_cb_t proto_fn, void *arg)
 {
-	memset(sbuf, 0, sizeof(*sbuf));
+	memset(sbuf, 0, RAW_SBUF_SIZE);
 	sbuf->proto_cb_arg = arg;
 	sbuf->proto_cb = proto_fn;
 }
-- 
2.39.5