Fix a bad interaction between "proxy-locking" and [http://www.sqlite.org/src/vdiff/aa6acfa8caa2ef59b4c16dfe42c4b5644da96905|aa6acfa8ca].

FossilOrigin-Name: 2a5c9e1dbf7f5f4b2081c964450a9305a4516f5b

manifest

@@ -1,5 +1,5 @@
-C Fix\ssome\serrors\sin\s[http://www.sqlite.org/src/vdiff/aa6acfa8caa2ef59b4c16dfe42c4b5644da96905|aa6acfa8ca].
-D 2009-08-24T18:57:58
+C Fix\sa\sbad\sinteraction\sbetween\s"proxy-locking"\sand\s[http://www.sqlite.org/src/vdiff/aa6acfa8caa2ef59b4c16dfe42c4b5644da96905|aa6acfa8ca].
+D 2009-08-25T05:57:48
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 73ddeec9dd10b85876c5c2ce1fdce627e1dcc7f8
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -144,7 +144,7 @@ F src/os.c 9fea283e336ee31caa4654d6cb05a129a1c42d2f
 F src/os.h 00a1334a4eecee7f7bef79ac606b88d325119f21
 F src/os_common.h 8c61457df58f1a4bd5f5adc3e90e01b37bf7afbc
 F src/os_os2.c bed77dc26e3a95ce4a204936b9a1ca6fe612fcc5
-F src/os_unix.c 5fc8443b16d64faf3db374f6dda959cfe3202a03
+F src/os_unix.c 96e2e409df8851a31fdb2d7430ad73fea7b0a104
 F src/os_win.c 58bb163f327e79726dd119344d908e4d98483c3f
 F src/pager.c a47be286477ed6c7b9a342dd53d4e4043f29d8c2
 F src/pager.h 11852d044c86cf5a9d6e34171fb0c4fcf1f6265f
@@ -747,7 +747,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P f7eb1efc37d0658d66b3b86d5afd5419d22bfe92
-R 83c4813ff710350c0fba94b0a5e87768
+P 82d1934a428a34c292a612fb67bbcea262990e0f
+R d7c1a30840419801458f3ecc7f6aa251
 U dan
-Z 0b89a0ea45e445bcb467bd70aa77089d
+Z 6b17644948440e13ab90b6fbc376f045

manifest.uuid

@@ -1 +1 @@
-82d1934a428a34c292a612fb67bbcea262990e0f
+2a5c9e1dbf7f5f4b2081c964450a9305a4516f5b

src/os_unix.c

@@ -3902,7 +3902,7 @@ static int unixOpen(
   noLock = eType!=SQLITE_OPEN_MAIN_DB;
 
 #if SQLITE_PREFER_PROXY_LOCKING
-  if( zPath!=NULL && !noLock ){
+  if( zPath!=NULL && !noLock && pVfs->xOpen ){
     char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
     int useProxy = 0;
 
@@ -4617,33 +4617,43 @@ static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
 ** but also for freeing the memory associated with the file descriptor.
 */
 static int proxyCreateUnixFile(const char *path, unixFile **ppFile) {
-  int fd;
-  int dirfd = -1;
   unixFile *pNew;
+  int flags = SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE;
   int rc = SQLITE_OK;
   sqlite3_vfs dummyVfs;
 
-  fd = open(path, O_RDWR | O_CREAT, SQLITE_DEFAULT_FILE_PERMISSIONS);
-  if( fd<0 ){
-    return SQLITE_CANTOPEN;
-  }
-  
   pNew = (unixFile *)sqlite3_malloc(sizeof(unixFile));
-  if( pNew==NULL ){
-    rc = SQLITE_NOMEM;
-    goto end_create_proxy;
+  if( !pNew ){
+    return SQLITE_NOMEM;
   }
   memset(pNew, 0, sizeof(unixFile));
 
+  /* Call unixOpen() to open the proxy file. The flags passed to unixOpen()
+  ** suggest that the file being opened is a "main database". This is
+  ** necessary as other file types do not necessarily support locking. It
+  ** is better to use unixOpen() instead of opening the file directly with
+  ** open(), as unixOpen() sets up the various mechanisms required to
+  ** make sure a call to close() does not cause the system to discard
+  ** POSIX locks prematurely.
+  **
+  ** It is important that the xOpen member of the VFS object passed to 
+  ** unixOpen() is NULL. This tells unixOpen() may try to open a proxy-file 
+  ** for the proxy-file (creating a potential infinite loop).
+  */
   dummyVfs.pAppData = (void*)&autolockIoFinder;
-  rc = fillInUnixFile(&dummyVfs, fd, dirfd, (sqlite3_file*)pNew, path, 0, 0);
-  if( rc==SQLITE_OK ){
-    *ppFile = pNew;
-    return SQLITE_OK;
+  dummyVfs.xOpen = 0;
+  rc = unixOpen(&dummyVfs, path, (sqlite3_file *)pNew, flags, &flags);
+  if( rc==SQLITE_OK && (flags&SQLITE_OPEN_READONLY) ){
+    pNew->pMethod->xClose((sqlite3_file *)pNew);
+    rc = SQLITE_CANTOPEN;
   }
-end_create_proxy:    
-  close(fd); /* silently leak fd if error, we're already in error */
-  sqlite3_free(pNew);
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(pNew);
+    pNew = 0;
+  }
+
+  *ppFile = pNew;
   return rc;
 }