From: Jim Jagielski <jim@apache.org>
Date: Tue, 4 Sep 2001 18:15:16 +0000 (+0000)
Subject: Add the AcceptMutex runtime directive, which allows for the
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0940525e855fe1f26177ab5664f76bd41184b6ec;p=thirdparty%2Fapache%2Fhttpd.git

Add the AcceptMutex runtime directive, which allows for the
accept mutexing method to be set at runtime (the suite of
methods is set at compile time still).
PR:
Obtained from:
Submitted by:
Reviewed by:


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@90892 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/src/CHANGES b/src/CHANGES
index 8f2db5df690..af7967c5a20 100644
--- a/src/CHANGES
+++ b/src/CHANGES
@@ -1,5 +1,15 @@
 Changes with Apache 1.3.21
 
+  *) Addition of the AcceptMutex runtime directive. The accept mutex
+     method is now runtime controllable. The suite of available methods
+     per platform is defined at compile time (with HAVE_FOO_SERIALIZED_ACCEPT
+     noting that the method is available and works, and
+     USE_FOO_SERIALIZED_ACCEPT noting that it should be the default
+     method in absense of any AcceptMutex line, or via AcceptMutex default)
+     and selectable at runtime. The full (current) suite is uslock,
+     pthread, sysvsem, fcntl, flock, os2sem, tpfcore and none, but
+     not all platforms accept all methods. [Jim Jagielski]
+
   *) Parallel to a change in Apache-2.0, the manual directory was
      moved out of the DocumentRoot tree to simplify the separation
      of private content&configuration from server's on-line
diff --git a/src/PORTING b/src/PORTING
index 52103d24f1d..daabd772269 100644
--- a/src/PORTING
+++ b/src/PORTING
@@ -244,13 +244,20 @@ build for your OS.
      USE_MMAP_FILES:
       Enable the use of mmap() for sending static files. If HAVE_MMAP
       is not #defined, this will automatically be unset.
+--
 
  USE_*_SERIALIZED_ACCEPT:
   See htdocs/manual/misc/perf-tuning.html for an in-depth discussion of
-  why these are required.  These are choices for implementing a semaphore
-  between children entering accept().  A complete port should define one
-  of these, many may work and it's worthwhile timing them.  Without these
-  the server will not implement multiple Listen directives reliably.
+  why these are required.  These are choices for implementing a mutex
+  between children entering accept().  A complete port should define at
+  least one of these, many may work and it's worthwhile timing them.
+  Without these the server will not implement multiple Listen directives
+  reliably.  Please note that as of 1.3.21, we can set the method at runtime.
+  To so do, we specify which methods are available at compile time
+  with the HAVE_FOO_SERIALIZED_ACCEPT #defines. The USE_FOO_SERIALIZED_ACCEPT
+  is used to pick the default version of all those available. These are
+  set at compile time usually in include/ap_config.h but can also be
+  done at the compile command line.
 
      USE_FCNTL_SERIALIZED_ACCEPT:
       Use fcntl() to implement the semaphore.
diff --git a/src/include/ap_config.h b/src/include/ap_config.h
index 5571addcfde..0c77f2d94dd 100644
--- a/src/include/ap_config.h
+++ b/src/include/ap_config.h
@@ -118,7 +118,7 @@ stat() properly */
 typedef int rlim_t;
 #define JMP_BUF sigjmp_buf
 #define NO_LONG_DOUBLE
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define _BSD_SOURCE
 #define EAGAIN EWOULDBLOCK
 int initgroups (char *, int);     
@@ -154,7 +154,7 @@ extern char *inet_ntoa();
 #define S_IREAD  S_IRUSR
 #define S_IWRITE S_IWUSR
 #define PF_INET  AF_INET
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 
 #elif defined(SUNOS4)
 #define HAVE_GMTOFF 1
@@ -170,7 +170,7 @@ char *mktemp(char *);
 typedef int rlim_t;
 #define memmove(a,b,c) bcopy(b,a,c)
 #define NO_LINGCLOSE
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define NEED_DIFFTIME
 #define HAVE_SYSLOG 1
 
@@ -179,6 +179,8 @@ typedef int rlim_t;
 #define NO_KILLPG
 #undef NO_SETSID
 #define bzero(a,b) memset(a,0,b)
+#define HAVE_SYSVSEM_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #if !defined(USE_SYSVSEM_SERIALIZED_ACCEPT) && \
     !defined(USE_PTHREAD_SERIALIZED_ACCEPT)
 #define USE_FCNTL_SERIALIZED_ACCEPT
@@ -197,6 +199,10 @@ int gethostname(char *name, int namelen);
  * there's some weird conflict with non-BSD signals */
 #define NO_KILLPG
 #undef NO_SETSID
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_USLOCK_SERIALIZED_ACCEPT
+#define HAVE_SYSVSEM_SERIALIZED_ACCEPT
 #if !defined(USE_FLOCK_SERIALIZED_ACCEPT) && \
     !defined(USE_USLOCK_SERIALIZED_ACCEPT) && \
     !defined(USE_SYSVSEM_SERIALIZED_ACCEPT)
@@ -226,7 +232,7 @@ int gethostname(char *name, int namelen);
 #undef HAVE_GMTOFF
 #define NO_KILLPG
 #undef NO_SETSID
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #ifndef _HPUX_SOURCE
 #define _HPUX_SOURCE
 #endif
@@ -245,12 +251,12 @@ typedef int rlim_t;
 #define HAVE_SHMGET
 #define USE_SHMGET_SCOREBOARD
 #undef  HAVE_GMTOFF
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 /* feeling brave?  want to try using POSIX mutexes? */
 /* #define HAVE_MMAP */
 /* #define USE_MMAP_SCOREBOARD */
 /* #define USE_MMAP_FILES */
-/* #define USE_PTHREAD_SERIALIZED_ACCEPT */
+/* #define HAVE_PTHREAD_SERIALIZED_ACCEPT */
 #define NO_KILLPG
 #undef  NO_SETSID
 #define HAVE_SYSLOG
@@ -274,6 +280,7 @@ typedef int rlim_t;
 #ifdef NEED_RLIM_T
 typedef int rlim_t;
 #endif
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #if !defined(USE_PTHREAD_SERIALIZED_ACCEPT)
 #define USE_FCNTL_SERIALIZED_ACCEPT
 #endif
@@ -307,7 +314,7 @@ typedef int rlim_t;
 #define USE_MMAP_FILES
 #define NO_LONG_DOUBLE
 #define HAVE_SYSLOG 1
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 
 #elif defined(PARAGON)
@@ -329,7 +336,7 @@ typedef int rlim_t;
 #define HAVE_SYSLOG 1
 #define USE_MMAP_FILES 1
 #define USE_MMAP_SCOREBOARD 1
-#define USE_FCNTL_SERIALIZED_ACCEPT 1
+#define HAVE_FCNTL_SERIALIZED_ACCEPT 1
 #define JMP_BUF sigjmp_buf
 #undef NO_SETSID
 #if SEQUENT < 40
@@ -432,6 +439,8 @@ typedef int pid_t;
 #define HAVE_SNPRINTF
 #define JMP_BUF jmp_buf
 #define USE_LONGJMP
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #define USE_FLOCK_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 
@@ -475,7 +484,8 @@ typedef int pid_t;
  * in new-httpd archives for performance numbers indicating these
  * are the right choices for linux 2.2.x and later
  */
-#define USE_SYSVSEM_SERIALIZED_ACCEPT
+#define HAVE_SYSVSEM_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT 
 #include <sys/sem.h>
 #if _SEM_SEMUN_UNDEFINED
@@ -515,7 +525,7 @@ typedef int rlim_t;
 
 #elif defined(SCO5)
 
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #define HAVE_MMAP 1
 #define USE_MMAP_SCOREBOARD
 #define USE_MMAP_FILES
@@ -547,7 +557,7 @@ extern char *crypt();
 #undef NO_SETSID
 #define NEED_STRDUP
 /* fcntl() locking is expensive with NFS */
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 #define HAVE_SHMGET 1
 #define USE_SHMGET_SCOREBOARD
@@ -576,6 +586,7 @@ extern char *crypt();
 #endif /* MPRAS */
 #define bzero(a,b) memset(a,0,b)
 /* A lot of SVR4 systems need this */
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #ifndef USE_SYSVSEM_SERIALIZED_ACCEPT
 #define USE_FCNTL_SERIALIZED_ACCEPT
 #endif
@@ -593,7 +604,7 @@ extern char *crypt();
 
 #elif defined(UW)
 #if UW < 700
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #define NO_LINGCLOSE
 #define NO_KILLPG
 #endif
@@ -627,7 +638,7 @@ extern char *crypt();
 #endif
 #define bzero(a,b) memset(a,0,b)
 /* A lot of SVR4 systems need this */
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #define ap_inet_addr inet_network
 #define HAVE_SYSLOG 1
 
@@ -646,7 +657,7 @@ extern char *crypt();
 #define HAVE_MMAP 1
 #define USE_MMAP_SCOREBOARD
 #define USE_MMAP_FILES
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 
 #elif defined(UTS21)
@@ -700,7 +711,7 @@ extern char *crypt();
 (defined(__FreeBSD_version) && (__FreeBSD_version < 220000))
 typedef quad_t rlim_t;
 #endif
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 #define HAVE_SYSLOG 1
 #define SYS_SIGLIST sys_siglist
@@ -726,7 +737,7 @@ int initgroups(char *, int);
 #include <unix.h>
 #define HAVE_MMAP 1
 #define USE_POSIX_SCOREBOARD
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 #define HAVE_SYSLOG 1
 
@@ -734,8 +745,9 @@ int initgroups(char *, int);
 #undef HAVE_GMTOFF
 #undef USE_MMAP_SCOREBOARD
 #undef USE_SHMGET_SCOREBOARD
-#undef USE_FCNTL_SERIALIZED_ACCEPT
-#undef USE_FLOCK_SERIALIZED_ACCEPT
+#undef HAVE_FCNTL_SERIALIZED_ACCEPT
+#undef HAVE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_NONE_SERIALIZED_ACCEPT
 #define USE_LONGJMP
 #undef NO_KILLPG
 #undef NO_SETSID
@@ -753,7 +765,7 @@ typedef int rlim_t;
 #define NO_KILLPG
 #undef NO_SETSID
 #define bzero(a,b) memset(a,0,b)
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #define HAVE_MMAP 1
 #define USE_MMAP_SCOREBOARD
 #define USE_MMAP_FILES
@@ -774,7 +786,7 @@ typedef int rlim_t;
 #define MAXSOCKETS 2048
 #define USE_OS2_SCOREBOARD
 #define NO_RELIABLE_PIPED_LOGS
-#define USE_OS2SEM_SERIALIZED_ACCEPT
+#define HAVE_OS2SEM_SERIALIZED_ACCEPT
 #define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 #define NO_SLACK
 #define FOPEN_REQUIRES_T
@@ -788,7 +800,7 @@ typedef int rlim_t;
 #ifndef __MACHTEN_68K__
 #define __MACHTEN_68K__
 #endif
-#define USE_FLOCK_SERIALIZED_ACCEPT
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
 #define NO_USE_SIGACTION
 #define JMP_BUF sigjmp_buf
 #define USE_LONGJMP
@@ -796,7 +808,7 @@ typedef int rlim_t;
 #else
 #define HAVE_SHMGET 1
 #define USE_SHMGET_SCOREBOARD
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #endif
 
 /* Convex OS v11 */
@@ -821,7 +833,7 @@ typedef int rlim_t;
 #undef NO_SETSID
 #define HAVE_SHMGET 1
 #define USE_SHMGET_SCOREBOARD
-#define USE_FCNTL_SERIALIZED_ACCEPT
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
 #define HAVE_SYSLOG 1
 
 #elif defined(NEWSOS)
@@ -909,7 +921,7 @@ typedef int rlim_t;
 #define USE_SHMGET_SCOREBOARD
 /*#define USE_TPF_SCOREBOARD*/
 #define USE_TPF_ACCEPT
-#define USE_TPF_CORE_SERIALIZED_ACCEPT
+#define HAVE_TPF_CORE_SERIALIZED_ACCEPT
 #define USE_TPF_SELECT
 #define S_IREAD S_IRUSR
 #define S_IWRITE S_IWUSR
@@ -931,7 +943,7 @@ typedef int rlim_t;
 #define USE_SHMGET_SCOREBOARD
 #define USE_MMAP_FILES
 #define NEED_UNION_SEMUN
-#define USE_SYSVSEM_SERIALIZED_ACCEPT
+#define HAVE_SYSVSEM_SERIALIZED_ACCEPT
 #define _POSIX_SOURCE
 #include <signal.h>
 #ifdef SIGDUMP  /* SIGDUMP is not defined by OS/390 v1r2 */
@@ -1159,6 +1171,32 @@ int setrlimit(int, struct rlimit *);
 #undef USE_SHMGET_SCOREBOARD
 #endif
 
+/* A USE_FOO_SERIALIZED_ACCEPT implies a HAVE_FOO_SERIALIZED_ACCEPT */
+#if defined(USE_USLOCK_SERIALIZED_ACCEPT) && !defined(HAVE_USLOCK_SERIALIZED_ACCEPT)
+#define HAVE_USLOCK_SERIALIZED_ACCEPT
+#endif
+#if defined(USE_PTHREAD_SERIALIZED_ACCEPT) && !defined(HAVE_PTHREAD_SERIALIZED_ACCEPT)
+#define HAVE_PTHREAD_SERIALIZED_ACCEPT
+#endif
+#if defined(USE_SYSVSEM_SERIALIZED_ACCEPT) && !defined(HAVE_SYSVSEM_SERIALIZED_ACCEPT)
+#define HAVE_SYSVSEM_SERIALIZED_ACCEPT
+#endif
+#if defined(USE_FCNTL_SERIALIZED_ACCEPT) && !defined(HAVE_FCNTL_SERIALIZED_ACCEPT)
+#define HAVE_FCNTL_SERIALIZED_ACCEPT
+#endif
+#if defined(USE_FLOCK_SERIALIZED_ACCEPT) && !defined(HAVE_FLOCK_SERIALIZED_ACCEPT)
+#define HAVE_FLOCK_SERIALIZED_ACCEPT
+#endif
+#if defined(USE_OS2SEM_SERIALIZED_ACCEPT) && !defined(HAVE_OS2SEM_SERIALIZED_ACCEPT)
+#define HAVE_OS2SEM_SERIALIZED_ACCEPT
+#endif
+#if defined(USE_TPF_CORE_SERIALIZED_ACCEPT) && !defined(HAVE_TPF_CORE_SERIALIZED_ACCEPT)
+#define HAVE_TPF_CORE_SERIALIZED_ACCEPT
+#endif
+#if defined(USE_NONE_SERIALIZED_ACCEPT) && !defined(HAVE_NONE_SERIALIZED_ACCEPT)
+#define HAVE_NONE_SERIALIZED_ACCEPT
+#endif
+
 #ifndef LOGNAME_MAX
 #define LOGNAME_MAX 25
 #endif
diff --git a/src/include/http_main.h b/src/include/http_main.h
index cc047eb5034..f480658a3b0 100644
--- a/src/include/http_main.h
+++ b/src/include/http_main.h
@@ -130,6 +130,10 @@ API_EXPORT(int) ap_check_alarm(void);
 
 void setup_signal_names(char *prefix);
 
+/* functions for determination and setting of accept() mutexing */
+char *ap_default_mutex_method(void);
+char *ap_init_mutex_method(char *t);
+
 #ifndef NO_OTHER_CHILD
 /*
  * register an other_child -- a child which the main loop keeps track of
diff --git a/src/lib/sdbm/sdbm_lock.c b/src/lib/sdbm/sdbm_lock.c
index a8c2fa437ab..aa0f148ba71 100644
--- a/src/lib/sdbm/sdbm_lock.c
+++ b/src/lib/sdbm/sdbm_lock.c
@@ -9,12 +9,13 @@
     /* The locking support:
      * Try to determine whether we should use fcntl() or flock().
      * Would be better ap_config.h could provide this... :-(
+     * Small monkey business to ensure that fcntl is preferred,
+     * unless we specified USE_FLOCK_SERIALIZED_ACCEPT during compile.
      */
-#if defined(USE_FCNTL_SERIALIZED_ACCEPT)
+#if defined(HAVE_FCNTL_SERIALIZED_ACCEPT) && !defined(USE_FLOCK_SERIALIZED_ACCEPT)
 #define USE_FCNTL 1
 #include <fcntl.h>
-#endif
-#if defined(USE_FLOCK_SERIALIZED_ACCEPT)
+#elif defined(HAVE_FLOCK_SERIALIZED_ACCEPT)
 #define USE_FLOCK 1
 #include <sys/file.h>
 #endif
diff --git a/src/main/http_core.c b/src/main/http_core.c
index 0dd28f3b961..e845f1a96d1 100644
--- a/src/main/http_core.c
+++ b/src/main/http_core.c
@@ -1135,6 +1135,10 @@ static const char *set_add_default_charset(cmd_parms *cmd,
     }
     return NULL;
 }
+static const char *set_accept_mutex(cmd_parms *cmd, void *dummy, char *arg)
+{
+	return ap_init_mutex_method(arg);
+}
 
 static const char *set_document_root(cmd_parms *cmd, void *dummy, char *arg)
 {
@@ -3215,6 +3219,34 @@ static const command_rec core_cmds[] = {
   (void*)XtOffsetOf(core_dir_config, limit_req_body),
   OR_ALL, TAKE1,
   "Limit (in bytes) on maximum size of request message body" },
+{ "AcceptMutex", set_accept_mutex, NULL, RSRC_CONF, TAKE1,
+  "Serialized Accept Mutex; the methods " 
+#ifdef HAVE_USLOCK_SERIALIZED_ACCEPT
+    "'uslock' "                           
+#endif
+#ifdef HAVE_PTHREAD_SERIALIZED_ACCEPT
+    "'pthread' "
+#endif
+#ifdef HAVE_SYSVSEM_SERIALIZED_ACCEPT
+    "'sysvsem' "
+#endif
+#ifdef HAVE_FCNTL_SERIALIZED_ACCEPT
+    "'fcntl' "
+#endif
+#ifdef HAVE_FLOCK_SERIALIZED_ACCEPT
+    "'flock' "
+#endif
+#ifdef HAVE_OS2SEM_SERIALIZED_ACCEPT
+    "'os2sem' "
+#endif
+#ifdef HAVE_TPF_CORE_SERIALIZED_ACCEPT
+    "'tpfcore' "
+#endif
+#ifdef HAVE_NONE_SERIALIZED_ACCEPT
+    "'none' "
+#endif
+    "are compiled in"
+},
 
 /* EBCDIC Conversion directives: */
 #ifdef CHARSET_EBCDIC
diff --git a/src/main/http_main.c b/src/main/http_main.c
index 3e884cda032..3a7e148b9ef 100644
--- a/src/main/http_main.c
+++ b/src/main/http_main.c
@@ -258,6 +258,17 @@ API_VAR_EXPORT int ap_daemons_limit=0;
 time_t ap_restart_time=0;
 API_VAR_EXPORT int ap_suexec_enabled = 0;
 int ap_listenbacklog=0;
+
+struct accept_mutex_methods_s {
+    void (*child_init)(pool *p);
+    void (*init)(pool *p);
+    void (*on)(void);
+    void (*off)(void);
+    char *name;
+};
+typedef struct accept_mutex_methods_s accept_mutex_methods_s;
+accept_mutex_methods_s *amutex;
+
 #ifdef SO_ACCEPTFILTER
 int ap_acceptfilter =
 #ifdef AP_ACCEPTFILTER_OFF
@@ -503,7 +514,20 @@ static void clean_child_exit(int code)
     exit(code);
 }
 
-#if defined(USE_FCNTL_SERIALIZED_ACCEPT) || defined(USE_FLOCK_SERIALIZED_ACCEPT)
+/*
+ * Start of accept() mutex fluff:
+ *  Concept: Each method has it's own distinct set of mutex functions,
+ *   which it shoves in a nice struct for us. We then pick
+ *   which struct to use. We tell Apache which methods we
+ *   support via HAVE_FOO_SERIALIZED_ACCEPT. We can
+ *   specify the default via USE_FOO_SERIALIZED_ACCEPT
+ *   (this pre-1.3.21 builds which use that at the command-
+ *   line during builds work as expected). Without a set
+ *   method, we pick the 1st from the following order:
+ *   uslock, pthread, sysvsem, fcntl, flock, os2sem, tpfcore and none.
+ */
+
+#if defined(HAVE_FCNTL_SERIALIZED_ACCEPT) || defined(HAVE_FLOCK_SERIALIZED_ACCEPT)
 static void expand_lock_fname(pool *p)
 {
     /* XXXX possibly bogus cast */
@@ -512,15 +536,13 @@ static void expand_lock_fname(pool *p)
 }
 #endif
 
-#if defined (USE_USLOCK_SERIALIZED_ACCEPT)
-
+#if defined (HAVE_USLOCK_SERIALIZED_ACCEPT)
 #include <ulocks.h>
-
 static ulock_t uslock = NULL;
 
-#define accept_mutex_child_init(x)
+#define accept_mutex_child_init_uslock(x)
 
-static void accept_mutex_init(pool *p)
+static void accept_mutex_init_uslock(pool *p)
 {
     ptrdiff_t old;
     usptr_t *us;
@@ -551,7 +573,7 @@ static void accept_mutex_init(pool *p)
     }
 }
 
-static void accept_mutex_on(void)
+static void accept_mutex_on_uslock(void)
 {
     switch (ussetlock(uslock)) {
     case 1:
@@ -566,7 +588,7 @@ static void accept_mutex_on(void)
     }
 }
 
-static void accept_mutex_off(void)
+static void accept_mutex_off_uslock(void)
 {
     if (usunsetlock(uslock) == -1) {
 	perror("usunsetlock");
@@ -574,7 +596,16 @@ static void accept_mutex_off(void)
     }
 }
 
-#elif defined (USE_PTHREAD_SERIALIZED_ACCEPT)
+accept_mutex_methods_s accept_mutex_uslock_s = {
+    NULL,
+    accept_mutex_init_uslock,
+    accept_mutex_on_uslock,
+    accept_mutex_off_uslock,
+    "uslock"
+};
+#endif
+
+#if defined (HAVE_PTHREAD_SERIALIZED_ACCEPT)
 
 /* This code probably only works on Solaris ... but it works really fast
  * on Solaris.  Note that pthread mutexes are *NOT* released when a task
@@ -589,7 +620,7 @@ static int have_accept_mutex;
 static sigset_t accept_block_mask;
 static sigset_t accept_previous_mask;
 
-static void accept_mutex_child_cleanup(void *foo)
+static void accept_mutex_child_cleanup_pthread(void *foo)
 {
     if (accept_mutex != (void *)(caddr_t)-1
 	&& have_accept_mutex) {
@@ -597,12 +628,12 @@ static void accept_mutex_child_cleanup(void *foo)
     }
 }
 
-static void accept_mutex_child_init(pool *p)
+static void accept_mutex_child_init_pthread(pool *p)
 {
-    ap_register_cleanup(p, NULL, accept_mutex_child_cleanup, ap_null_cleanup);
+    ap_register_cleanup(p, NULL, accept_mutex_child_cleanup_pthread, ap_null_cleanup);
 }
 
-static void accept_mutex_cleanup(void *foo)
+static void accept_mutex_cleanup_pthread(void *foo)
 {
     if (accept_mutex != (void *)(caddr_t)-1
 	&& munmap((caddr_t) accept_mutex, sizeof(*accept_mutex))) {
@@ -611,7 +642,7 @@ static void accept_mutex_cleanup(void *foo)
     accept_mutex = (void *)(caddr_t)-1;
 }
 
-static void accept_mutex_init(pool *p)
+static void accept_mutex_init_pthread(pool *p)
 {
     pthread_mutexattr_t mattr;
     int fd;
@@ -645,10 +676,10 @@ static void accept_mutex_init(pool *p)
     sigdelset(&accept_block_mask, SIGHUP);
     sigdelset(&accept_block_mask, SIGTERM);
     sigdelset(&accept_block_mask, SIGUSR1);
-    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
+    ap_register_cleanup(p, NULL, accept_mutex_cleanup_pthread, ap_null_cleanup);
 }
 
-static void accept_mutex_on(void)
+static void accept_mutex_on_pthread(void)
 {
     int err;
 
@@ -670,7 +701,7 @@ static void accept_mutex_on(void)
     ap_unblock_alarms();
 }
 
-static void accept_mutex_off(void)
+static void accept_mutex_off_pthread(void)
 {
     int err;
 
@@ -692,7 +723,16 @@ static void accept_mutex_off(void)
     }
 }
 
-#elif defined (USE_SYSVSEM_SERIALIZED_ACCEPT)
+accept_mutex_methods_s accept_mutex_pthread_s = {
+    accept_mutex_child_init_pthread,
+    accept_mutex_init_pthread,
+    accept_mutex_on_pthread,
+    accept_mutex_off_pthread,
+    "pthread"
+};
+#endif
+
+#if defined (HAVE_SYSVSEM_SERIALIZED_ACCEPT)
 
 #include <sys/types.h>
 #include <sys/ipc.h>
@@ -716,7 +756,7 @@ static struct sembuf op_off;
  * means we have to be sure to clean this up or else we'll leak
  * semaphores.
  */
-static void accept_mutex_cleanup(void *foo)
+static void accept_mutex_cleanup_sysvsem(void *foo)
 {
     union semun ick;
 
@@ -727,9 +767,9 @@ static void accept_mutex_cleanup(void *foo)
     semctl(sem_id, 0, IPC_RMID, ick);
 }
 
-#define accept_mutex_child_init(x)
+#define accept_mutex_child_init_sysvsem(x)
 
-static void accept_mutex_init(pool *p)
+static void accept_mutex_init_sysvsem(pool *p)
 {
     union semun ick;
     struct semid_ds buf;
@@ -758,7 +798,7 @@ static void accept_mutex_init(pool *p)
 	    exit(APEXIT_INIT);
 	}
     }
-    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
+    ap_register_cleanup(p, NULL, accept_mutex_cleanup_sysvsem, ap_null_cleanup);
 
     /* pre-initialize these */
     op_on.sem_num = 0;
@@ -769,7 +809,7 @@ static void accept_mutex_init(pool *p)
     op_off.sem_flg = SEM_UNDO;
 }
 
-static void accept_mutex_on(void)
+static void accept_mutex_on_sysvsem(void)
 {
     while (semop(sem_id, &op_on, 1) < 0) {
 	if (errno != EINTR) {
@@ -779,7 +819,7 @@ static void accept_mutex_on(void)
     }
 }
 
-static void accept_mutex_off(void)
+static void accept_mutex_off_sysvsem(void)
 {
     while (semop(sem_id, &op_off, 1) < 0) {
 	if (errno != EINTR) {
@@ -789,19 +829,28 @@ static void accept_mutex_off(void)
     }
 }
 
-#elif defined(USE_FCNTL_SERIALIZED_ACCEPT)
+accept_mutex_methods_s accept_mutex_sysvsem_s = {
+    NULL,
+    accept_mutex_init_sysvsem,
+    accept_mutex_on_sysvsem,
+    accept_mutex_off_sysvsem,
+    "sysvsem"
+};
+#endif
+
+#if defined(HAVE_FCNTL_SERIALIZED_ACCEPT)
 static struct flock lock_it;
 static struct flock unlock_it;
 
 static int lock_fd = -1;
 
-#define accept_mutex_child_init(x)
+#define accept_mutex_child_init_fcntl(x)
 
 /*
  * Initialize mutex lock.
  * Must be safe to call this on a restart.
  */
-static void accept_mutex_init(pool *p)
+static void accept_mutex_init_fcntl(pool *p)
 {
 
     lock_it.l_whence = SEEK_SET;	/* from current point */
@@ -825,7 +874,7 @@ static void accept_mutex_init(pool *p)
     unlink(ap_lock_fname);
 }
 
-static void accept_mutex_on(void)
+static void accept_mutex_on_fcntl(void)
 {
     int ret;
 
@@ -842,7 +891,7 @@ static void accept_mutex_on(void)
     }
 }
 
-static void accept_mutex_off(void)
+static void accept_mutex_off_fcntl(void)
 {
     int ret;
 
@@ -858,11 +907,20 @@ static void accept_mutex_off(void)
     }
 }
 
-#elif defined(USE_FLOCK_SERIALIZED_ACCEPT)
+accept_mutex_methods_s accept_mutex_fcntl_s = {
+    NULL,
+    accept_mutex_init_fcntl,
+    accept_mutex_on_fcntl,
+    accept_mutex_off_fcntl,
+    "fcntl"
+};
+#endif
 
-static int lock_fd = -1;
+#if defined(HAVE_FLOCK_SERIALIZED_ACCEPT)
+
+static int flock_fd = -1;
 
-static void accept_mutex_cleanup(void *foo)
+static void accept_mutex_cleanup_flock(void *foo)
 {
     unlink(ap_lock_fname);
 }
@@ -871,11 +929,11 @@ static void accept_mutex_cleanup(void *foo)
  * Initialize mutex lock.
  * Done by each child at it's birth
  */
-static void accept_mutex_child_init(pool *p)
+static void accept_mutex_child_init_flock(pool *p)
 {
 
-    lock_fd = ap_popenf(p, ap_lock_fname, O_WRONLY, 0600);
-    if (lock_fd == -1) {
+    flock_fd = ap_popenf(p, ap_lock_fname, O_WRONLY, 0600);
+    if (flock_fd == -1) {
 	ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
 		    "Child cannot open lock file: %s", ap_lock_fname);
 	clean_child_exit(APEXIT_CHILDINIT);
@@ -886,24 +944,24 @@ static void accept_mutex_child_init(pool *p)
  * Initialize mutex lock.
  * Must be safe to call this on a restart.
  */
-static void accept_mutex_init(pool *p)
+static void accept_mutex_init_flock(pool *p)
 {
     expand_lock_fname(p);
     unlink(ap_lock_fname);
-    lock_fd = ap_popenf(p, ap_lock_fname, O_CREAT | O_WRONLY | O_EXCL, 0600);
-    if (lock_fd == -1) {
+    flock_fd = ap_popenf(p, ap_lock_fname, O_CREAT | O_WRONLY | O_EXCL, 0600);
+    if (flock_fd == -1) {
 	ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
 		    "Parent cannot open lock file: %s", ap_lock_fname);
 	exit(APEXIT_INIT);
     }
-    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
+    ap_register_cleanup(p, NULL, accept_mutex_cleanup_flock, ap_null_cleanup);
 }
 
-static void accept_mutex_on(void)
+static void accept_mutex_on_flock(void)
 {
     int ret;
 
-    while ((ret = flock(lock_fd, LOCK_EX)) < 0 && errno == EINTR)
+    while ((ret = flock(flock_fd, LOCK_EX)) < 0 && errno == EINTR)
 	continue;
 
     if (ret < 0) {
@@ -913,20 +971,29 @@ static void accept_mutex_on(void)
     }
 }
 
-static void accept_mutex_off(void)
+static void accept_mutex_off_flock(void)
 {
-    if (flock(lock_fd, LOCK_UN) < 0) {
+    if (flock(flock_fd, LOCK_UN) < 0) {
 	ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
 		    "flock: LOCK_UN: Error freeing accept lock. Exiting!");
 	clean_child_exit(APEXIT_CHILDFATAL);
     }
 }
 
-#elif defined(USE_OS2SEM_SERIALIZED_ACCEPT)
+accept_mutex_methods_s accept_mutex_flock_s = {
+    accept_mutex_child_init_flock,
+    accept_mutex_init_flock,
+    accept_mutex_on_flock,
+    accept_mutex_off_flock,
+    "flock"
+};
+#endif
+
+#if defined(HAVE_OS2SEM_SERIALIZED_ACCEPT)
 
 static HMTX lock_sem = -1;
 
-static void accept_mutex_cleanup(void *foo)
+static void accept_mutex_cleanup_os2sem(void *foo)
 {
     DosReleaseMutexSem(lock_sem);
     DosCloseMutexSem(lock_sem);
@@ -936,7 +1003,7 @@ static void accept_mutex_cleanup(void *foo)
  * Initialize mutex lock.
  * Done by each child at it's birth
  */
-static void accept_mutex_child_init(pool *p)
+static void accept_mutex_child_init_os2sem(pool *p)
 {
     int rc = DosOpenMutexSem(NULL, &lock_sem);
 
@@ -945,7 +1012,7 @@ static void accept_mutex_child_init(pool *p)
 		    "Child cannot open lock semaphore, rc=%d", rc);
 	clean_child_exit(APEXIT_CHILDINIT);
     } else {
-        ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
+        ap_register_cleanup(p, NULL, accept_mutex_cleanup_os2sem, ap_null_cleanup);
     }
 }
 
@@ -953,7 +1020,7 @@ static void accept_mutex_child_init(pool *p)
  * Initialize mutex lock.
  * Must be safe to call this on a restart.
  */
-static void accept_mutex_init(pool *p)
+static void accept_mutex_init_os2sem(pool *p)
 {
     int rc = DosCreateMutexSem(NULL, &lock_sem, DC_SEM_SHARED, FALSE);
 
@@ -963,10 +1030,10 @@ static void accept_mutex_init(pool *p)
 	exit(APEXIT_INIT);
     }
 
-    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
+    ap_register_cleanup(p, NULL, accept_mutex_cleanup_os2sem, ap_null_cleanup);
 }
 
-static void accept_mutex_on(void)
+static void accept_mutex_on_os2sem(void)
 {
     int rc = DosRequestMutexSem(lock_sem, SEM_INDEFINITE_WAIT);
 
@@ -977,7 +1044,7 @@ static void accept_mutex_on(void)
     }
 }
 
-static void accept_mutex_off(void)
+static void accept_mutex_off_os2sem(void)
 {
     int rc = DosReleaseMutexSem(lock_sem);
     
@@ -988,52 +1055,201 @@ static void accept_mutex_off(void)
     }
 }
 
-#elif defined(USE_TPF_CORE_SERIALIZED_ACCEPT)
+accept_mutex_methods_s accept_mutex_os2sem_s = {
+    accept_mutex_child_init_os2sem,
+    accept_mutex_init_os2sem,
+    accept_mutex_on_os2sem,
+    accept_mutex_off_os2sem,
+    "os2sem"
+};
+#endif
+
+#if defined(HAVE_TPF_CORE_SERIALIZED_ACCEPT)
 
 static int tpf_core_held;
 
-static void accept_mutex_cleanup(void *foo)
+static void accept_mutex_cleanup_tpfcore(void *foo)
 {
     if(tpf_core_held)
         coruc(RESOURCE_KEY);
 }
 
-#define accept_mutex_init(x)
+#define accept_mutex_init_tpfcore(x)
 
-static void accept_mutex_child_init(pool *p)
+static void accept_mutex_child_init_tpfcore(pool *p)
 {
-    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
+    ap_register_cleanup(p, NULL, accept_mutex_cleanup_tpfcore, ap_null_cleanup);
     tpf_core_held = 0;
 }
 
-static void accept_mutex_on(void)
+static void accept_mutex_on_tpfcore(void)
 {
     corhc(RESOURCE_KEY);
     tpf_core_held = 1;
     ap_check_signals();
 }
 
-static void accept_mutex_off(void)
+static void accept_mutex_off_tpfcore(void)
 {
     coruc(RESOURCE_KEY);
     tpf_core_held = 0;
     ap_check_signals();
 }
 
-#else
-/* Default --- no serialization.  Other methods *could* go here,
- * as #elifs...
- */
+accept_mutex_methods_s accept_mutex_tpfcore_s = {
+    accept_mutex_child_init_tpfcore,
+    accept_mutex_init_tpfcore,
+    accept_mutex_on_tpfcore,
+    accept_mutex_off_tpfcore,
+    "tpfcore"
+};
+#endif
+
+/* Generally, HAVE_NONE_SERIALIZED_ACCEPT simply won't work but
+ * for testing purposes, here it is... */
+#if defined HAVE_NONE_SERIALIZED_ACCEPT
 #if !defined(MULTITHREAD)
 /* Multithreaded systems don't complete between processes for
  * the sockets. */
 #define NO_SERIALIZED_ACCEPT
-#define accept_mutex_child_init(x)
-#define accept_mutex_init(x)
-#define accept_mutex_on()
-#define accept_mutex_off()
+#endif 
+
+accept_mutex_methods_s accept_mutex_none_s = {
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    "none"
+};
 #endif
+
+#define AP_FPTR1(x,y)	{ if (x) ((* x)(y)); }
+#define AP_FPTR0(x)	{ if (x) ((* x)()); }
+
+#define accept_mutex_child_init(x) 	AP_FPTR1(amutex->child_init,x)
+#define accept_mutex_init(x) 		AP_FPTR1(amutex->init,x)
+#define accept_mutex_off() 		AP_FPTR0(amutex->off)
+#define accept_mutex_on() 		AP_FPTR0(amutex->on)
+
+char *ap_default_mutex_method(void)
+{
+    char *t;
+#if defined USE_USLOCK_SERIALIZED_ACCEPT
+    t = "uslock";
+#elif defined USE_PTHREAD_SERIALIZED_ACCEPT
+    t = "pthread";
+#elif defined USE_SYSVSEM_SERIALIZED_ACCEPT
+    t = "sysvsem";
+#elif defined USE_FCNTL_SERIALIZED_ACCEPT
+    t = "fcntl";
+#elif defined USE_FLOCK_SERIALIZED_ACCEPT
+    t = "flock";
+#elif defined USE_OS2SEM_SERIALIZED_ACCEPT
+    t = "os2sem";
+#elif defined USE_TPF_CORE_SERIALIZED_ACCEPT
+    t = "tpfcore";
+#elif defined USE_NONE_SERIALIZED_ACCEPT
+    t = "none";
+#else
+    t = "default";
+#endif
+#if defined HAVE_USLOCK_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"uslock"))))
+    	return "uslock";
+#endif
+#if defined HAVE_PTHREAD_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"pthread"))))
+    	return "pthread";
+#endif
+#if defined HAVE_SYSVSEM_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"sysvsem"))))
+    	return "sysvsem";
+#endif
+#if defined HAVE_FCNTL_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"fcntl"))))
+    	return "fcntl";
+#endif
+#if defined HAVE_FLOCK_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"flock"))))
+    	return "flock";
+#endif
+#if defined HAVE_OS2SEM_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"os2sem"))))
+    	return "os2sem";
+#endif
+#if defined HAVE_TPF_CORE_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"tpfcore"))))
+    	return "tpfcore";
+#endif
+#if defined HAVE_NONE_SERIALIZED_ACCEPT
+    if ((!(strcasecmp(t,"default"))) || (!(strcasecmp(t,"none"))))
+    	return "none";
+#endif
+
+    fprintf(stderr, "No default accept serialization known!!\n");
+    exit(APEXIT_INIT);
+    /*NOTREACHED */
+    return "unknown";
+}
+
+char *ap_init_mutex_method(char *t)
+{
+    if (!(strcasecmp(t,"default")))
+	t = ap_default_mutex_method();
+
+#if defined HAVE_USLOCK_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"uslock"))) {
+    	amutex = &accept_mutex_uslock_s;
+    } else 
+#endif
+#if defined HAVE_PTHREAD_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"pthread"))) {
+    	amutex = &accept_mutex_pthread_s;
+    } else 
 #endif
+#if defined HAVE_SYSVSEM_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"sysvsem"))) {
+    	amutex = &accept_mutex_sysvsem_s;
+    } else 
+#endif
+#if defined HAVE_FCNTL_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"fcntl"))) {
+    	amutex = &accept_mutex_fcntl_s;
+    } else
+#endif
+#if defined HAVE_FLOCK_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"flock"))) {
+    	amutex = &accept_mutex_flock_s;
+    } else 
+#endif
+#if defined HAVE_OS2SEM_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"os2sem"))) {
+    	amutex = &accept_mutex_os2sem_s;
+    } else 
+#endif
+#if defined HAVE_TPF_CORE_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"tpfcore"))) {
+    	amutex = &accept_mutex_tpfcore_s;
+    } else 
+#endif
+#if defined HAVE_NONE_SERIALIZED_ACCEPT
+    if (!(strcasecmp(t,"none"))) {
+    	amutex = &accept_mutex_none_s;
+    } else
+#endif
+    {
+    if (server_conf) {
+        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, server_conf,
+                    "Requested serialization method '%s' not available",t);
+        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, server_conf,
+                    "Using compiled-in default of '%s'", ap_default_mutex_method());
+    } else {
+        fprintf(stderr, "Requested serialization method '%s' not available;\n", t);
+        fprintf(stderr, "Using compiled-in default of '%s'\n", ap_default_mutex_method());
+    }
+    }
+    return NULL;
+}
 
 /* On some architectures it's safe to do unserialized accept()s in the single
  * Listen case.  But it's never safe to do it in the case where there's
@@ -3713,20 +3929,29 @@ static void show_compile_settings(void)
 #ifdef NO_LINGCLOSE
     printf(" -D NO_LINGCLOSE\n");
 #endif
-#ifdef USE_FCNTL_SERIALIZED_ACCEPT
-    printf(" -D USE_FCNTL_SERIALIZED_ACCEPT\n");
+#ifdef HAVE_FCNTL_SERIALIZED_ACCEPT
+    printf(" -D HAVE_FCNTL_SERIALIZED_ACCEPT\n");
+#endif
+#ifdef HAVE_FLOCK_SERIALIZED_ACCEPT
+    printf(" -D HAVE_FLOCK_SERIALIZED_ACCEPT\n");
 #endif
-#ifdef USE_FLOCK_SERIALIZED_ACCEPT
-    printf(" -D USE_FLOCK_SERIALIZED_ACCEPT\n");
+#ifdef HAVE_USLOCK_SERIALIZED_ACCEPT
+    printf(" -D HAVE_USLOCK_SERIALIZED_ACCEPT\n");
 #endif
-#ifdef USE_USLOCK_SERIALIZED_ACCEPT
-    printf(" -D USE_USLOCK_SERIALIZED_ACCEPT\n");
+#ifdef HAVE_SYSVSEM_SERIALIZED_ACCEPT
+    printf(" -D HAVE_SYSVSEM_SERIALIZED_ACCEPT\n");
 #endif
-#ifdef USE_SYSVSEM_SERIALIZED_ACCEPT
-    printf(" -D USE_SYSVSEM_SERIALIZED_ACCEPT\n");
+#ifdef HAVE_PTHREAD_SERIALIZED_ACCEPT
+    printf(" -D HAVE_PTHREAD_SERIALIZED_ACCEPT\n");
 #endif
-#ifdef USE_PTHREAD_SERIALIZED_ACCEPT
-    printf(" -D USE_PTHREAD_SERIALIZED_ACCEPT\n");
+#ifdef HAVE_OS2SEM_SERIALIZED_ACCEPT
+    printf(" -D HAVE_OS2SEM_SERIALIZED_ACCEPT\n");
+#endif
+#ifdef HAVE_TPF_CORE_SERIALIZED_ACCEPT
+    printf(" -D HAVE_TPF_CORE_SERIALIZED_ACCEPT\n");
+#endif
+#ifdef HAVE_NONE_SERIALIZED_ACCEPT
+    printf(" -D HAVE_NONE_SERIALIZED_ACCEPT\n");
 #endif
 #ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
     printf(" -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT\n");
@@ -3884,7 +4109,7 @@ static void child_main(int child_num_arg)
 
     /* needs to be done before we switch UIDs so we have permissions */
     reopen_scoreboard(pchild);
-    SAFE_ACCEPT(accept_mutex_child_init(pchild));
+    SAFE_ACCEPT((accept_mutex_child_init(pchild)));
 
     set_group_privs();
 #ifdef MPE
@@ -3982,7 +4207,7 @@ static void child_main(int child_num_arg)
 	 */
 
 	/* Lock around "accept", if necessary */
-	SAFE_ACCEPT(accept_mutex_on());
+	SAFE_ACCEPT((accept_mutex_on()));
 
 	for (;;) {
 	    if (ap_listeners->next != ap_listeners) {
@@ -4688,6 +4913,8 @@ static void standalone_main(int argc, char **argv)
 	ap_clear_pool(pconf);
 	ptrans = ap_make_sub_pool(pconf);
 
+	ap_init_mutex_method(ap_default_mutex_method());
+
 	server_conf = ap_read_config(pconf, ptrans, ap_server_confname);
 	setup_listeners(pconf);
 	ap_clear_pool(plog);
@@ -4743,6 +4970,9 @@ static void standalone_main(int argc, char **argv)
 	}
 	ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, server_conf,
 		    "Server built: %s", ap_get_server_built());
+	ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, server_conf,
+		    "Accept mutex: %s (Default: %s)",
+		     amutex->name, ap_default_mutex_method());
 	restart_pending = shutdown_pending = 0;
 
 	while (!restart_pending && !shutdown_pending) {
diff --git a/src/modules/standard/mod_rewrite.h b/src/modules/standard/mod_rewrite.h
index 47c55dbdeb8..c67bd9e2eed 100644
--- a/src/modules/standard/mod_rewrite.h
+++ b/src/modules/standard/mod_rewrite.h
@@ -144,12 +144,13 @@
     /* The locking support:
      * Try to determine whether we should use fcntl() or flock().
      * Would be better ap_config.h could provide this... :-(
+     * Small monkey business to ensure that fcntl is preferred,
+     * unless we specified USE_FLOCK_SERIALIZED_ACCEPT during compile.
      */
-#if defined(USE_FCNTL_SERIALIZED_ACCEPT)
+#if defined(HAVE_FCNTL_SERIALIZED_ACCEPT) && !defined(USE_FLOCK_SERIALIZED_ACCEPT)
 #define USE_FCNTL 1
 #include <fcntl.h>
-#endif
-#if defined(USE_FLOCK_SERIALIZED_ACCEPT)
+#elif defined(HAVE_FLOCK_SERIALIZED_ACCEPT)
 #define USE_FLOCK 1
 #include <sys/file.h>
 #endif