Experimental changes to put sqlite3_temp_directory behind a mutex.

FossilOrigin-Name: 5ee3515fbb88bf1ae5f8b507844f82dcc429380b6ebeab9b09b52b25ee60a60d

4 files changed, 62 insertions, 15 deletions

diff --git a/src/os_unix.c b/src/os_unix.c
index f809eca9f..fd7a50dcd 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -5855,6 +5855,7 @@ static const char *unixTempFileDir(void){
 static int unixGetTempname(int nBuf, char *zBuf){
   const char *zDir;
   int iLimit = 0;
+  int rc = SQLITE_OK;
 
   /* It's odd to simulate an io-error here, but really this is just
   ** using the io-error infrastructure to test that SQLite handles this
@@ -5863,18 +5864,26 @@ static int unixGetTempname(int nBuf, char *zBuf){
   zBuf[0] = 0;
   SimulateIOError( return SQLITE_IOERR );
 
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   zDir = unixTempFileDir();
-  if( zDir==0 ) return SQLITE_IOERR_GETTEMPPATH;
-  do{
-    u64 r;
-    sqlite3_randomness(sizeof(r), &r);
-    assert( nBuf>2 );
-    zBuf[nBuf-2] = 0;
-    sqlite3_snprintf(nBuf, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX"%llx%c",
-                     zDir, r, 0);
-    if( zBuf[nBuf-2]!=0 || (iLimit++)>10 ) return SQLITE_ERROR;
-  }while( osAccess(zBuf,0)==0 );
-  return SQLITE_OK;
+  if( zDir==0 ){
+    rc = SQLITE_IOERR_GETTEMPPATH;
+  }else{
+    do{
+      u64 r;
+      sqlite3_randomness(sizeof(r), &r);
+      assert( nBuf>2 );
+      zBuf[nBuf-2] = 0;
+      sqlite3_snprintf(nBuf, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX"%llx%c",
+                       zDir, r, 0);
+      if( zBuf[nBuf-2]!=0 || (iLimit++)>10 ){
+        rc = SQLITE_ERROR;
+        break;
+      }
+    }while( osAccess(zBuf,0)==0 );
+  }
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
 }
 
 #if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
diff --git a/src/os_win.c b/src/os_win.c
index 8832c8012..591f57ee5 100644
--- a/src/os_win.c
+++ b/src/os_win.c
@@ -1922,6 +1922,7 @@ int sqlite3_win32_set_directory8(
   int rc = sqlite3_initialize();
   if( rc ) return rc;
 #endif
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   if( type==SQLITE_WIN32_DATA_DIRECTORY_TYPE ){
     ppDirectory = &sqlite3_data_directory;
   }else if( type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE ){
@@ -1936,14 +1937,19 @@ int sqlite3_win32_set_directory8(
     if( zValue && zValue[0] ){
       zCopy = sqlite3_mprintf("%s", zValue);
       if ( zCopy==0 ){
-        return SQLITE_NOMEM_BKPT;
+        rc = SQLITE_NOMEM_BKPT;
+        goto set_directory8_done;
       }
     }
     sqlite3_free(*ppDirectory);
     *ppDirectory = zCopy;
-    return SQLITE_OK;
+    rc = SQLITE_OK;
+  }else{
+    rc = SQLITE_ERROR;
   }
-  return SQLITE_ERROR;
+set_directory8_done:
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
 }
 
 /*
@@ -4718,6 +4724,18 @@ static int winMakeEndInDirSep(int nBuf, char *zBuf){
 }
 
 /*
+** If sqlite3_temp_directory is not, take the mutex and return true.
+**
+** If sqlite3_temp_directory is NULL, omit the mutex and return false.
+*/
+static int winTempDirDefined(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  if( sqlite3_temp_directory!=0 ) return 1;
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return 0;
+}
+
+/*
 ** Create a temporary file name and store the resulting pointer into pzBuf.
 ** The pointer returned in pzBuf must be freed via sqlite3_free().
 */
@@ -4753,20 +4771,23 @@ static int winGetTempname(sqlite3_vfs *pVfs, char **pzBuf){
   */
   nDir = nMax - (nPre + 15);
   assert( nDir>0 );
-  if( sqlite3_temp_directory ){
+  if( winTempDirDefined() ){
     int nDirLen = sqlite3Strlen30(sqlite3_temp_directory);
     if( nDirLen>0 ){
       if( !winIsDirSep(sqlite3_temp_directory[nDirLen-1]) ){
         nDirLen++;
       }
       if( nDirLen>nDir ){
+        sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
         sqlite3_free(zBuf);
         OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
         return winLogError(SQLITE_ERROR, 0, "winGetTempname1", 0);
       }
       sqlite3_snprintf(nMax, zBuf, "%s", sqlite3_temp_directory);
     }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   }
+
 #if defined(__CYGWIN__)
   else{
     static const char *azDirs[] = {
@@ -5579,6 +5600,7 @@ static int winFullPathname(
   SimulateIOError( return SQLITE_ERROR );
   UNUSED_PARAMETER(nFull);
   assert( nFull>=pVfs->mxPathname );
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
     /*
     ** NOTE: We are dealing with a relative path name and the data
@@ -5629,6 +5651,7 @@ static int winFullPathname(
       sqlite3_free(zOut);
     }
   }
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   return SQLITE_OK;
 #endif
 
@@ -5636,6 +5659,7 @@ static int winFullPathname(
   SimulateIOError( return SQLITE_ERROR );
   /* WinCE has no concept of a relative pathname, or so I am told. */
   /* WinRT has no way to convert a relative path to an absolute one. */
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
     /*
     ** NOTE: We are dealing with a relative path name and the data
@@ -5648,6 +5672,7 @@ static int winFullPathname(
   }else{
     sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zRelative);
   }
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   return SQLITE_OK;
 #endif
 
@@ -5658,6 +5683,7 @@ static int winFullPathname(
   ** current working directory has been unlinked.
   */
   SimulateIOError( return SQLITE_ERROR );
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
   if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
     /*
     ** NOTE: We are dealing with a relative path name and the data
@@ -5667,6 +5693,7 @@ static int winFullPathname(
     */
     sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
                      sqlite3_data_directory, winGetDirSep(), zRelative);
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
     return SQLITE_OK;
   }
   zConverted = winConvertFromUtf8Filename(zRelative);
diff --git a/src/pragma.c b/src/pragma.c
index 2dd792f27..9d46a10dc 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -965,6 +965,7 @@ void sqlite3Pragma(
   **
   */
   case PragTyp_TEMP_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
     if( !zRight ){
       returnSingleText(v, sqlite3_temp_directory);
     }else{
@@ -974,6 +975,7 @@ void sqlite3Pragma(
         rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
         if( rc!=SQLITE_OK || res==0 ){
           sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
           goto pragma_out;
         }
       }
@@ -991,6 +993,7 @@ void sqlite3Pragma(
       }
 #endif /* SQLITE_OMIT_WSD */
     }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
     break;
   }
 
@@ -1009,6 +1012,7 @@ void sqlite3Pragma(
   **
   */
   case PragTyp_DATA_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
     if( !zRight ){
       returnSingleText(v, sqlite3_data_directory);
     }else{
@@ -1018,6 +1022,7 @@ void sqlite3Pragma(
         rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
         if( rc!=SQLITE_OK || res==0 ){
           sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
           goto pragma_out;
         }
       }
@@ -1029,6 +1034,7 @@ void sqlite3Pragma(
       }
 #endif /* SQLITE_OMIT_WSD */
     }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
     break;
   }
 #endif
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 21d15378f..eef09e1f0 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -199,6 +199,11 @@
 #include "sqlite3.h"
 
 /*
+** Reuse the STATIC_LRU for mutex access to sqlite3_temp_directory.
+*/
+#define SQLITE_MUTEX_STATIC_TEMPDIR SQLITE_MUTEX_STATIC_LRU
+
+/*
 ** Include the configuration header output by 'configure' if we're using the
 ** autoconf-based build
 */