1 files changed, 102 insertions, 0 deletions
diff --git a/src/tools/tor_runner.c b/src/tools/tor_runner.c
new file mode 100644
index 0000000000..cad57a7665
--- /dev/null
+++ b/src/tools/tor_runner.c
@@ -0,0 +1,102 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2017, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file tor_runner.c
+ * @brief Experimental module to emulate tor_run_main() API with fork+exec
+ *
+ * The functions here are meant to allow the application developer to
+ * use the tor_run_main() API without having to care whether Tor is
+ * running in-process or out-of-process.  For in-process usage, the
+ * developer can link Tor as a library and call tor_run_main(); for
+ * out-of-process usage, the developer can link this library instead.
+ *
+ * This interface is EXPERIMENTAL; please let us know if you would like
+ * to depend on it.  We don't know yet whether it will be reliable in
+ * practice.
+ */
+
+/* NOTE: This module is supposed to work without the standard Tor utility
+ * functions.  Don't add more dependencies!
+ */
+
+#include "tor_api.h"
+#include "tor_api_internal.h"
+
+#include "orconfig.h"
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#ifdef HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef __GNUC__
+#define __attribute__(x)
+#endif
+
+static void child(const tor_main_configuration_t *cfg)
+  __attribute__((noreturn));
+
+int
+tor_run_main(const tor_main_configuration_t *cfg)
+{
+  pid_t pid = fork();
+  if (pid == 0) {
+    child(cfg);
+    exit(0); /* Unreachable */
+  }
+
+  pid_t stopped_pid;
+  int status = 0;
+  do {
+    stopped_pid = waitpid(pid, &status, 0);
+  } while (stopped_pid == -1);
+
+  /* Note: these return values are not documented.  No return value is
+   * documented! */
+
+  if (stopped_pid != pid) {
+    return -99999;
+  }
+  if (WIFSTOPPED(status)) {
+    return WEXITSTATUS(status);
+  }
+  if (WIFSIGNALED(status)) {
+    return -WTERMSIG(status);
+  }
+
+  return -999988;
+}
+
+/* circumlocution to avoid getting warned about calling calloc instead of
+ * tor_calloc. */
+#define real_calloc calloc
+#define real_free free
+
+static void
+child(const tor_main_configuration_t *cfg)
+{
+  /* XXXX Close unused file descriptors. */
+
+  char **args = real_calloc(cfg->argc+1, sizeof(char *));
+  memcpy(args, cfg->argv, cfg->argc * sizeof(char *));
+  args[cfg->argc] = NULL;
+
+  int rv = execv(BINDIR "/tor", args);
+
+  if (rv < 0) {
+    real_free(args);
+    exit(254);
+  } else {
+    abort(); /* Unreachable */
+  }
+}