- Rob Crittenden brought a patch to "add some locking for thread-safety to NSS

implementation".

CHANGES

@@ -6,6 +6,10 @@
 
                                   Changelog
 
+Daniel Stenberg (23 Sep 2008)
+- Rob Crittenden brought a patch to "add some locking for thread-safety to NSS
+  implementation".
+
 Daniel Stenberg (22 Sep 2008)
 - Made the SOCKS code use the new Curl_read_plain() function to fix the bug
   Markus Moeller reported: http://curl.haxx.se/mail/archive-2008-09/0016.html

RELEASE-NOTES

@@ -25,6 +25,7 @@ This release includes the following bugfixes:
  o GnuTLS-based multi interface doing HTTPS over proxy failed
  o recv() failures cause CURLE_RECV_ERROR
  o SFTP over SOCKS crash fixed
+ o thread-safety issues addressed for NSS-powered libcurls
 
 This release includes the following known bugs:
 
@@ -39,6 +40,6 @@ advice from friends like these:
 
  Keith Mok, Yang Tse, Daniel Fandrich, Guenter Knauf, Dmitriy Sergeyev,
  Linus Nielsen Feltzing, Martin Drasar, Stefan Krause, Dmitry Kurochkin,
- Mike Revi, Andres Garcia, Michael Goffioul, Markus Moeller
+ Mike Revi, Andres Garcia, Michael Goffioul, Markus Moeller, Rob Crittenden
 
         Thanks! (and sorry if I forgot to mention someone)

lib/nss.c

@@ -78,7 +78,9 @@
 
 PRFileDesc *PR_ImportTCPSocket(PRInt32 osfd);
 
-int initialized = 0;
+PRLock * nss_initlock = NULL;
+
+volatile int initialized = 0;
 
 #define HANDSHAKE_TIMEOUT 30
 
@@ -837,8 +839,11 @@ static SECStatus SelectClientCert(void *arg, PRFileDesc *sock,
  */
 int Curl_nss_init(void)
 {
-  if(!initialized)
+  /* curl_global_init() is not thread-safe so this test is ok */
+  if (nss_initlock == NULL) {
     PR_Init(PR_USER_THREAD, PR_PRIORITY_NORMAL, 256);
+    nss_initlock = PR_NewLock();
+  }
 
   /* We will actually initialize NSS later */
 
@@ -848,7 +853,17 @@ int Curl_nss_init(void)
 /* Global cleanup */
 void Curl_nss_cleanup(void)
 {
-  NSS_Shutdown();
+  /* This function isn't required to be threadsafe and this is only done
+   * as a safety feature.
+   */
+  PR_Lock(nss_initlock);
+  if (initialized)
+    NSS_Shutdown();
+  PR_Unlock(nss_initlock);
+
+  PR_DestroyLock(nss_initlock);
+  nss_initlock = NULL;
+
   initialized = 0;
 }
 
@@ -926,7 +941,8 @@ CURLcode Curl_nss_connect(struct connectdata *conn, int sockindex)
     return CURLE_OK;
 
   /* FIXME. NSS doesn't support multiple databases open at the same time. */
-  if(!initialized) {
+  PR_Lock(nss_initlock);
+  if(!initialized && !NSS_IsInitialized()) {
     initialized = 1;
 
     certDir = getenv("SSL_DIR"); /* Look in $SSL_DIR */
@@ -950,6 +966,8 @@ CURLcode Curl_nss_connect(struct connectdata *conn, int sockindex)
     if(rv != SECSuccess) {
       infof(conn->data, "Unable to initialize NSS database\n");
       curlerr = CURLE_SSL_CACERT_BADFILE;
+      initialized = 0;
+      PR_Unlock(nss_initlock);
       goto error;
     }
 
@@ -972,6 +990,7 @@ CURLcode Curl_nss_connect(struct connectdata *conn, int sockindex)
     }
 #endif
   }
+  PR_Unlock(nss_initlock);
 
   model = PR_NewTCPSocket();
   if(!model)