Jeremy Brown's OpenSSL thread-locking example

1 files changed, 77 insertions, 0 deletions

diff --git a/docs/examples/opensslthreadlock.c b/docs/examples/opensslthreadlock.c
new file mode 100644
index 000000000..82de206da
--- /dev/null
+++ b/docs/examples/opensslthreadlock.c
@@ -0,0 +1,77 @@
+/*****************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * $Id$
+ *
+ * Example source code to show one way to set the necessary OpenSSL locking
+ * callbacks if you want to do multi-threaded transfers with HTTPS/FTPS with
+ * libcurl built to use OpenSSL.
+ *
+ * This is not a complete stand-alone example.
+ *
+ * Author: Jeremy Brown
+ */
+
+#define MUTEX_TYPE       pthread_mutex_t
+#define MUTEX_SETUP(x)   pthread_mutex_init(&(x), NULL)
+#define MUTEX_CLEANUP(x) pthread_mutex_destroy(&(x))
+#define MUTEX_LOCK(x)    pthread_mutex_lock(&(x))
+#define MUTEX_UNLOCK(x)  pthread_mutex_unlock(&(x))
+#define THREAD_ID        pthread_self(  )
+
+
+void handle_error(const char *file, int lineno, const char *msg){
+     fprintf(stderr, ** %s:%i %s\n, file, lineno, msg);
+     ERR_print_errors_fp(stderr);
+     /* exit(-1); */
+ }
+
+/* This array will store all of the mutexes available to OpenSSL. */
+static MUTEX_TYPE *mutex_buf= NULL;
+
+
+static void locking_function(int mode, int n, const char * file, int line)
+{
+  if (mode & CRYPTO_LOCK)
+    MUTEX_LOCK(mutex_buf[n]);
+  else
+    MUTEX_UNLOCK(mutex_buf[n]);
+}
+
+static unsigned long id_function(void)
+{
+  return ((unsigned long)THREAD_ID);
+}
+
+int thread_setup(void)
+{
+  int i;
+
+  mutex_buf = (MUTEX_TYPE *)malloc(CRYPTO_num_locks(  ) * sizeof(MUTEX_TYPE));
+  if (!mutex_buf)
+    return 0;
+  for (i = 0;  i < CRYPTO_num_locks(  );  i++)
+    MUTEX_SETUP(mutex_buf[i]);
+  CRYPTO_set_id_callback(id_function);
+  CRYPTO_set_locking_callback(locking_function);
+  return 1;
+}
+
+int thread_cleanup(void)
+{
+  int i;
+
+  if (!mutex_buf)
+    return 0;
+  CRYPTO_set_id_callback(NULL);
+  CRYPTO_set_locking_callback(NULL);
+  for (i = 0;  i < CRYPTO_num_locks(  );  i++)
+    MUTEX_CLEANUP(mutex_buf[i]);
+  free(mutex_buf);
+  mutex_buf = NULL;
+  return 1;
+}