Fix a benign data race in os_unix.c that might trouble tsan and similar tools.

FossilOrigin-Name: 95806ac1dabe4598170061d903ae30f09bafac149ff6696963a7e056ac846cdb

1 files changed, 25 insertions, 12 deletions

diff --git a/src/os_unix.c b/src/os_unix.c
index 0e184af3c..cd619f5c0 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -5799,24 +5799,34 @@ static int fillInUnixFile(
 }
 
 /*
+** Directories to consider for temp files.
+*/
+static const char *azTempDirs[] = {
+  0,
+  0,
+  "/var/tmp",
+  "/usr/tmp",
+  "/tmp",
+  "."
+};
+
+/*
+** Initialize first two members of azTempDirs[] array.
+*/
+static void unixTempFileInit(void){
+  azTempDirs[0] = getenv("SQLITE_TMPDIR");
+  azTempDirs[1] = getenv("TMPDIR");
+}
+
+/*
 ** Return the name of a directory in which to put temporary files.
 ** If no suitable temporary file directory can be found, return NULL.
 */
 static const char *unixTempFileDir(void){
-  static const char *azDirs[] = {
-     0,
-     0,
-     "/var/tmp",
-     "/usr/tmp",
-     "/tmp",
-     "."
-  };
   unsigned int i = 0;
   struct stat buf;
   const char *zDir = sqlite3_temp_directory;
 
-  if( !azDirs[0] ) azDirs[0] = getenv("SQLITE_TMPDIR");
-  if( !azDirs[1] ) azDirs[1] = getenv("TMPDIR");
   while(1){
     if( zDir!=0
      && osStat(zDir, &buf)==0
@@ -5825,8 +5835,8 @@ static const char *unixTempFileDir(void){
     ){
       return zDir;
     }
-    if( i>=sizeof(azDirs)/sizeof(azDirs[0]) ) break;
-    zDir = azDirs[i++];
+    if( i>=sizeof(azTempDirs)/sizeof(azTempDirs[0]) ) break;
+    zDir = azTempDirs[i++];
   }
   return 0;
 }
@@ -8098,6 +8108,9 @@ int sqlite3_os_init(void){
   assert( UNIX_SHM_DMS==128   );  /* Byte offset of the deadman-switch */
 #endif
 
+  /* Initialize temp file dir array. */
+  unixTempFileInit();
+
   return SQLITE_OK; 
 }