+#endif
+
+#ifdef WIN32
+# define setenv(n,v,f) _putenv(n "=" v)
+#endif
+ /* Set up a basic environment. After we are called by /init the
+ * environment is essentially empty.
+ * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
+ */
+ setenv ("PATH", "/usr/bin:/bin", 1);
+ setenv ("SHELL", "/bin/sh", 1);
+ setenv ("LC_ALL", "C", 1);
+
+#ifndef WIN32
+ /* We document that umask defaults to 022 (it should be this anyway). */
+ umask (022);
+#else
+ /* This is the default for Windows anyway. It's not even clear if
+ * Windows ever uses this -- the MSDN documentation for the function
+ * contains obvious errors.
+ */
+ _umask (0);
+#endif
+
+ /* Get the vmchannel string.
+ *
+ * Sources:
+ * --channel/-c option on the command line
+ * guestfs_vmchannel=... from the kernel command line
+ * guestfs=... from the kernel command line
+ * built-in default
+ *
+ * At the moment we expect this to contain "tcp:ip:port" but in
+ * future it might contain a device name, eg. "/dev/vcon4" for
+ * virtio-console vmchannel.
+ */
+ if (vmchannel == NULL && cmdline) {
+ char *p;
+ size_t len;
+
+ p = strstr (cmdline, "guestfs_vmchannel=");
+ if (p) {
+ len = strcspn (p + 18, " \t\n");
+ vmchannel = strndup (p + 18, len);
+ if (!vmchannel) {
+ perror ("strndup");
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ /* Old libraries passed guestfs=host:port. Rewrite it as tcp:host:port. */
+ if (vmchannel == NULL) {
+ /* We will rewrite it part of the "guestfs=" string with
+ * "tcp:" hence p + 4 below. */
+ p = strstr (cmdline, "guestfs=");
+ if (p) {
+ len = strcspn (p + 4, " \t\n");
+ vmchannel = strndup (p + 4, len);
+ if (!vmchannel) {
+ perror ("strndup");
+ exit (EXIT_FAILURE);
+ }
+ memcpy (vmchannel, "tcp:", 4);
+ }
+ }
+ }
+
+ /* Default vmchannel. */
+ if (vmchannel == NULL) {
+ vmchannel = strdup ("tcp:" GUESTFWD_ADDR ":" GUESTFWD_PORT);
+ if (!vmchannel) {
+ perror ("strdup");
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ if (verbose)
+ printf ("vmchannel: %s\n", vmchannel);
+
+ /* Connect to vmchannel. */
+ int sock = -1;
+
+ if (STREQLEN (vmchannel, "tcp:", 4)) {
+ /* Resolve the hostname. */
+ struct addrinfo *res, *rr;
+ struct addrinfo hints;
+ int r;
+ char *host, *port;
+
+ host = vmchannel+4;
+ port = strchr (host, ':');
+ if (port) {
+ port[0] = '\0';
+ port++;
+ } else {
+ fprintf (stderr, "vmchannel: expecting \"tcp:<ip>:<port>\": %s\n",
+ vmchannel);
+ exit (EXIT_FAILURE);
+ }
+
+ memset (&hints, 0, sizeof hints);
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_flags = AI_ADDRCONFIG;
+ r = getaddrinfo (host, port, &hints, &res);
+ if (r != 0) {
+ fprintf (stderr, "%s:%s: %s\n",
+ host, port, gai_strerror (r));
+ exit (EXIT_FAILURE);
+ }