Enable -Wtype-limits by default (via -Wextra)

Removes a few smaller instances:
 - Fix return type check for socket() on Windows/Unixy
 - Ignore a few instances related to WSAWaitForMultipleEvents.
   The compiler says the check is currently useless, but
   we follow the API documentation.

Change-Id: Iaabddb6f81cd94863291b193aae9d384a8f9d871
Signed-off-by: Frank Lichtenheld <[email protected]>
Acked-by: Arne Schwabe <[email protected]>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1207
Message-Id: <[email protected]>
URL: https://www.mail-archive.com/[email protected]/msg34317.html
Signed-off-by: Gert Doering <[email protected]>

Author: flichtenheld

CMakeLists.txt

@@ -114,7 +114,7 @@ else ()
     check_and_add_compiler_flag(-Wstrict-prototypes StrictPrototypes)
     check_and_add_compiler_flag(-Wold-style-definition OldStyleDefinition)
     add_compile_options(-Wconversion -Wno-sign-conversion)
-    add_compile_options(-Wextra -Wno-sign-compare -Wno-type-limits -Wno-unused-parameter)
+    add_compile_options(-Wextra -Wno-sign-compare -Wno-unused-parameter)
     # clang doesn't have the different levels but also doesn't include it in -Wextra
     check_and_add_compiler_flag(-Wimplicit-fallthrough=2 GCCImplicitFallthrough)
     if (WIN32)

configure.ac

@@ -1410,7 +1410,7 @@ ACL_CHECK_ADD_COMPILE_FLAGS([-Wstrict-prototypes])
 ACL_CHECK_ADD_COMPILE_FLAGS([-Wold-style-definition])
 ACL_CHECK_ADD_COMPILE_FLAGS([-Wconversion -Wno-sign-conversion])
 ACL_CHECK_ADD_COMPILE_FLAGS([-Wall])
-ACL_CHECK_ADD_COMPILE_FLAGS([-Wextra -Wno-sign-compare -Wno-type-limits -Wno-unused-parameter])
+ACL_CHECK_ADD_COMPILE_FLAGS([-Wextra -Wno-sign-compare -Wno-unused-parameter])
 # clang doesn't have the different levels but also doesn't include it in -Wextra
 ACL_CHECK_ADD_COMPILE_FLAGS([-Wimplicit-fallthrough=2])
 if test "${WIN32}" = "yes"; then

src/openvpn/event.c

@@ -410,6 +410,13 @@ we_wait(struct event_set *es, const struct timeval *tv, struct event_set_return
     }
 #endif
 
+    /* WSA_WAIT_EVENT_0 == 0 but the API documentation is written in a way
+       that doesn't guarantee that. So we make useless checks. */
+#if defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wtype-limits"
+#endif
+
     /*
      * First poll our event list with 0 timeout
      */
@@ -474,6 +481,9 @@ we_wait(struct event_set *es, const struct timeval *tv, struct event_set_return
             return -1;
         }
     }
+#if defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
 }
 
 static struct event_set *

src/openvpn/socket.c

@@ -577,7 +577,8 @@ create_socket_tcp(struct addrinfo *addrinfo)
     ASSERT(addrinfo);
     ASSERT(addrinfo->ai_socktype == SOCK_STREAM);
 
-    if ((sd = socket(addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol)) < 0)
+    if ((sd = socket(addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol))
+        == SOCKET_UNDEFINED)
     {
         msg(M_ERR, "Cannot create TCP socket");
     }
@@ -608,7 +609,8 @@ create_socket_udp(struct addrinfo *addrinfo, const unsigned int flags)
     ASSERT(addrinfo);
     ASSERT(addrinfo->ai_socktype == SOCK_DGRAM);
 
-    if ((sd = socket(addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol)) < 0)
+    if ((sd = socket(addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol))
+        == SOCKET_UNDEFINED)
     {
         msg(M_ERR, "UDP: Cannot create UDP/UDP6 socket");
     }