Added fix for race conditions from os_unix.c; added saving of errno in two places.

FossilOrigin-Name: 13ed106c8c279422a6159e28c6887d13a88b7b8b

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\srace\scondition\sin\sos_unix.c\sthat\smay\soccur\swhen\sone\sthread\sis\sopening\sa\sconnection\sto\sa\sshared-memory\sblock\sand\sanother\sis\seither\sclosing\sor\slocking\sthe\ssame\sshared-memory.
-D 2010-07-20T18:59:01
+C Added\sfix\sfor\srace\sconditions\sfrom\sos_unix.c;\sadded\ssaving\sof\serrno\sin\stwo\splaces.
+D 2010-07-20T20:23:38
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in ec08dc838fd8110fe24c92e5130bcd91cbb1ff2e
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -155,7 +155,7 @@ F src/os.h 9dbed8c2b9c1f2f2ebabc09e49829d4777c26bf9
 F src/os_common.h a8f95b81eca8a1ab8593d23e94f8a35f35d4078f
 F src/os_os2.c 665876d5eec7585226b0a1cf5e18098de2b2da19
 F src/os_unix.c 3109e0e5a0d5551bab2e8c7322b20a3b8b171248
-F src/os_win.c 61734aad7f50b28f3c76eb4b19b63472f6d825d9
+F src/os_win.c 1f8b0a1a5bcf6289e7754d0d3c16cec16d4c93ab
 F src/pager.c 78ca1e1f3315c8227431c403c04d791dccf242fb
 F src/pager.h 879fdde5a102d2f21a3135d6f647530b21c2796c
 F src/parse.y 220a11ac72e2c9dffbf4cbe5fe462f328bd8d884
@@ -837,7 +837,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 92fe70dadde2eb551518d69ac2eaa6a0151d7dfe
-R df2a0b1fc90f9ee6b661361189db8cc8
-U dan
-Z 8ff12974b6f85e5f132c185f1bb718f5
+P 3b7330c19a5327322068e9460018fe0152b8ac87
+R f8111b94ec406976124441419b5d0d91
+U shaneh
+Z 1481f027c52f0315e6b182145a908af1

manifest.uuid

@@ -1 +1 @@
-3b7330c19a5327322068e9460018fe0152b8ac87
+13ed106c8c279422a6159e28c6887d13a88b7b8b

src/os_win.c

@@ -1193,7 +1193,7 @@ static int winDeviceCharacteristics(sqlite3_file *id){
 **
 **   winShmEnterMutex()
 **     assert( winShmMutexHeld() );
-**   winEnterLeave()
+**   winShmLeaveMutex()
 */
 static void winShmEnterMutex(void){
   sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
@@ -1320,13 +1320,19 @@ static int winShmSystemLock(
   }else{
     rc = LockFileEx(pFile->hFile.h, dwFlags, 0, nByte, 0, &ovlp);
   }
-  rc = (rc!=0) ? SQLITE_OK : SQLITE_BUSY;
+  
+  if( rc!= 0 ){
+    rc = SQLITE_OK;
+  }else{
+    pFile->lastErrno =  GetLastError();
+    rc = SQLITE_BUSY;
+  }
 
   OSTRACE(("SHM-LOCK %d %s %s 0x%08lx\n", 
            pFile->hFile.h,
            rc==SQLITE_OK ? "ok" : "failed",
            lockType==_SHM_UNLCK ? "UnlockFileEx" : "LockFileEx",
-           GetLastError()));
+           pFile->lastErrno));
 
   return rc;
 }
@@ -1457,14 +1463,24 @@ static int winOpenSharedMemory(winFile *pDbFd){
 
   /* Make the new connection a child of the winShmNode */
   p->pShmNode = pShmNode;
-  p->pNext = pShmNode->pFirst;
 #ifdef SQLITE_DEBUG
   p->id = pShmNode->nextShmId++;
 #endif
-  pShmNode->pFirst = p;
   pShmNode->nRef++;
   pDbFd->pShm = p;
   winShmLeaveMutex();
+
+  /* The reference count on pShmNode has already been incremented under
+  ** the cover of the winShmEnterMutex() mutex and the pointer from the
+  ** new (struct winShm) object to the pShmNode has been set. All that is
+  ** left to do is to link the new object into the linked list starting
+  ** at pShmNode->pFirst. This must be done while holding the pShmNode->mutex 
+  ** mutex.
+  */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  p->pNext = pShmNode->pFirst;
+  pShmNode->pFirst = p;
+  sqlite3_mutex_leave(pShmNode->mutex);
   return SQLITE_OK;
 
   /* Jump here on any error */
@@ -2072,6 +2088,7 @@ static int winOpen(
            h, zName, dwDesiredAccess, 
            h==INVALID_HANDLE_VALUE ? "failed" : "ok"));
   if( h==INVALID_HANDLE_VALUE ){
+    pFile->lastErrno = GetLastError();
     free(zConverted);
     if( flags & SQLITE_OPEN_READWRITE ){
       return winOpen(pVfs, zName, id,