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

FossilOrigin-Name: 95806ac1dabe4598170061d903ae30f09bafac149ff6696963a7e056ac846cdb

diff --git a/manifest b/manifest
index 4bc51a1e0c4d7ebca4cf63bde9c3d41111c0f5f8..9017b565ccd98ca17d1d720f0a8f29a627f374a0 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Minor\stweaks\sto\sthe\sway\sauxiliary\stools\sare\sbuilt,\sto\smake\sit\seasier\sto\ncustomize\sthe\sbuilds\swithout\shaving\sto\salter\sthe\scode.
-D 2021-11-18T20:56:59.677
+C Fix\sa\sbenign\sdata\srace\sin\sos_unix.c\sthat\smight\strouble\stsan\sand\ssimilar\stools.
+D 2021-11-19T14:02:43.242
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -534,7 +534,7 @@ F src/os.c b1c4f2d485961e9a5b6b648c36687d25047c252222e9660b7cc25a6e1ea436ab
 F src/os.h 26890f540b475598cd9881dcc68931377b8d429d3ea3e2eeb64470cde64199f8
 F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85
 F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
-F src/os_unix.c 8e14b40fd02f70e234030c2bee45215ff8835293adc13a08e9718c29bff61401
+F src/os_unix.c f5ad51cfd024116db8531feab9efd831c2621436dca1464e4ff1e8af9bf3252e
 F src/os_win.c 77d39873836f1831a9b0b91894fec45ab0e9ca8e067dc8c549e1d1eca1566fe9
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c bc10c191d18bffd3d76eda5f162799e43a9f875ecfe7c4869f752e2ddef87ea2
@@ -1933,7 +1933,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 7f42b8e1a25c0830fe81e4668318998af595826784a50780a5c1c0b4d95a2482
-R 7fc4ecd1448b6305c428d5164e326f71
-U drh
-Z 3efafb7c09c67bd8bd80d6c3aff384ef
+P 90b06b6f42918852cfb15258be462c6bed260c6a618b86fa9084bac72fa2f58f
+R 05a833efc38b4a3220b81b2f3a5823e3
+U dan
+Z fc95c03200d563c04629cc3672f249c7

diff --git a/manifest.uuid b/manifest.uuid
index d39645383242cdf0a21e8846a445d7d97ead2b24..61530bc4967fce987453ef88f303b8e71746f9d2 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-90b06b6f42918852cfb15258be462c6bed260c6a618b86fa9084bac72fa2f58f
\ No newline at end of file
+95806ac1dabe4598170061d903ae30f09bafac149ff6696963a7e056ac846cdb
\ No newline at end of file

diff --git a/src/os_unix.c b/src/os_unix.c
index 0e184af3c1c599f53d55d33126a78ad3977b7032..cd619f5c04ae99da5ec7581302e15f4ab364065d 100644 (file)
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -5798,25 +5798,35 @@ static int fillInUnixFile(
   return rc;
 }
 
+/*
+** 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; 
 }