Compile fixes and improvements for vxwork: fixed deadlock in semClose,

detect if fcntl is usable, fall back to named semaphores if not. (CVS 6460)

FossilOrigin-Name: efd0682b7e78acc4242cf257fc246350fc29b5c8

1 files changed, 44 insertions, 4 deletions

diff --git a/src/os_unix.c b/src/os_unix.c
index 75f595326..8776acaa5 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -43,7 +43,7 @@
 **   *  Definitions of sqlite3_vfs objects for all locking methods
 **      plus implementations of sqlite3_os_init() and sqlite3_os_end().
 **
-** $Id: os_unix.c,v 1.249 2009/04/07 00:35:20 drh Exp $
+** $Id: os_unix.c,v 1.250 2009/04/07 05:35:04 chw Exp $
 */
 #include "sqliteInt.h"
 #if SQLITE_OS_UNIX              /* This file is used on unix only */
@@ -2213,8 +2213,8 @@ static int semClose(sqlite3_file *id) {
     unixEnterMutex();
     releaseLockInfo(pFile->pLock);
     releaseOpenCnt(pFile->pOpen);
-    closeUnixFile(id);
     unixLeaveMutex();
+    closeUnixFile(id);
   }
   return SQLITE_OK;
 }
@@ -3207,7 +3207,7 @@ IOMETHODS(
   dotlockCheckReservedLock  /* xCheckReservedLock method */
 )
 
-#if SQLITE_ENABLE_LOCKING_STYLE
+#if SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORKS
 IOMETHODS(
   flockIoFinder,            /* Finder function name */
   flockIoMethods,           /* sqlite3_io_methods object name */
@@ -3331,6 +3331,44 @@ static const sqlite3_io_methods *(*const autolockIoFinder)(const char*,int)
 
 #endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
 
+#if OS_VXWORKS && SQLITE_ENABLE_LOCKING_STYLE
+/* 
+** This "finder" function attempts to determine the best locking strategy 
+** for the database file "filePath".  It then returns the sqlite3_io_methods
+** object that implements that strategy.
+**
+** This is for VXWorks only.
+*/
+static const sqlite3_io_methods *autolockIoFinderImpl(
+  const char *filePath,    /* name of the database file */
+  int fd                   /* file descriptor open on the database file */
+){
+  struct flock lockInfo;
+
+  if( !filePath ){
+    /* If filePath==NULL that means we are dealing with a transient file
+    ** that does not need to be locked. */
+    return &nolockIoMethods;
+  }
+
+  /* Test if fcntl() is supported and use POSIX style locks.
+  ** Otherwise fall back to the named semaphore method.
+  */
+  lockInfo.l_len = 1;
+  lockInfo.l_start = 0;
+  lockInfo.l_whence = SEEK_SET;
+  lockInfo.l_type = F_RDLCK;
+  if( fcntl(fd, F_GETLK, &lockInfo)!=-1 ) {
+    return &posixIoMethods;
+  }else{
+    return &semIoMethods;
+  }
+}
+static const sqlite3_io_methods *(*const autolockIoFinder)(const char*,int)
+        = autolockIoFinderImpl;
+
+#endif /* OS_VXWORKS && SQLITE_ENABLE_LOCKING_STYLE */
+
 /*
 ** An abstract type for a pointer to a IO method finder function:
 */
@@ -5061,7 +5099,7 @@ int sqlite3_os_init(void){
   ** array cannot be const.
   */
   static sqlite3_vfs aVfs[] = {
-#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+#if SQLITE_ENABLE_LOCKING_STYLE && (OS_VXWORKS || defined(__APPLE__))
     UNIXVFS("unix",          autolockIoFinder ),
 #else
     UNIXVFS("unix",          posixIoFinder ),
@@ -5073,8 +5111,10 @@ int sqlite3_os_init(void){
 #endif
 #if SQLITE_ENABLE_LOCKING_STYLE
     UNIXVFS("unix-posix",    posixIoFinder ),
+#if !OS_VXWORKS
     UNIXVFS("unix-flock",    flockIoFinder ),
 #endif
+#endif
 #if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
     UNIXVFS("unix-afp",      afpIoFinder ),
     UNIXVFS("unix-proxy",    proxyIoFinder ),