implement xl vncviewer

Implement xl vncviewer. The only difference from xm vncviewer is that we
obey the VNCVIEWER environment variable.

Signed-off-by: Gianni Tedesco <gianni.tedesco@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

tools/libxl/libxl.c

@@ -843,6 +843,69 @@ int libxl_primary_console_exec(struct libxl_ctx *ctx, uint32_t domid_vm)
         return libxl_console_exec(ctx, domid_vm, 0);
 }
 
+int libxl_vncviewer_exec(struct libxl_ctx *ctx, uint32_t domid, int autopass)
+{
+    const char *vnc_port, *vfb_back;
+    const char *vnc_listen = NULL, *vnc_pass = NULL;
+    int port = 0, autopass_fd = -1;
+    char *vnc_bin, *args[] = {
+        "vncviewer",
+        NULL, /* hostname:display */
+        NULL, /* -autopass */
+        NULL,
+    };
+
+    vnc_port = libxl_xs_read(ctx, XBT_NULL,
+                            libxl_sprintf(ctx,
+                            "/local/domain/%d/console/vnc-port", domid));
+    if ( vnc_port )
+        port = atoi(vnc_port) - 5900;
+
+    vfb_back = libxl_xs_read(ctx, XBT_NULL,
+                            libxl_sprintf(ctx,
+                            "/local/domain/%d/device/vfb/0/backend", domid));
+    if ( vfb_back ) {
+        vnc_listen = libxl_xs_read(ctx, XBT_NULL,
+                            libxl_sprintf(ctx,
+                            "/local/domain/%d/console/vnc-listen", domid));
+        if ( autopass )
+            vnc_pass = libxl_xs_read(ctx, XBT_NULL,
+                            libxl_sprintf(ctx,
+                            "/local/domain/%d/console/vnc-pass", domid));
+    }
+
+    if ( NULL == vnc_listen )
+        vnc_listen = "localhost";
+
+    if ( (vnc_bin = getenv("VNCVIEWER")) )
+        args[0] = vnc_bin;
+
+    args[1] = libxl_sprintf(ctx, "%s:%d", vnc_listen, port);
+
+    if ( vnc_pass ) {
+        char tmpname[] = "/tmp/vncautopass.XXXXXX";
+        autopass_fd = mkstemp(tmpname);
+        if ( autopass_fd < 0 )
+            goto skip_autopass;
+
+        if ( unlink(tmpname) )
+            /* should never happen */
+            XL_LOG_ERRNO(ctx, XL_LOG_ERROR, "unlink %s failed", tmpname);
+
+        if ( libxl_write_exactly(ctx, autopass_fd, vnc_pass, strlen(vnc_pass),
+                                    tmpname, "vnc password") ) {
+            do { close(autopass_fd); } while(errno == EINTR);
+            goto skip_autopass;
+        }
+
+        args[2] = "-autopass";
+    }
+
+skip_autopass:
+    libxl_exec(autopass_fd, -1, -1, args[0], args);
+    return 0;
+}
+
 static char ** libxl_build_device_model_args(struct libxl_ctx *ctx,
                                              libxl_device_model_info *info,
                                              libxl_device_nic *vifs,

tools/libxl/libxl.h

@@ -400,6 +400,7 @@ int libxl_domain_core_dump(struct libxl_ctx *ctx, uint32_t domid, const char *fi
 int libxl_domain_setmaxmem(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb);
 int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb, int enforce);
 
+int libxl_vncviewer_exec(struct libxl_ctx *ctx, uint32_t domid, int autopass);
 int libxl_console_exec(struct libxl_ctx *ctx, uint32_t domid, int cons_num);
 /* libxl_primary_console_exec finds the domid and console number
  * corresponding to the primary console of the given vm, then calls

tools/libxl/xl.h

@@ -30,6 +30,7 @@ int main_info(int argc, char **argv);
 int main_cd_eject(int argc, char **argv);
 int main_cd_insert(int argc, char **argv);
 int main_console(int argc, char **argv);
+int main_vncviewer(int argc, char **argv);
 int main_pcilist(int argc, char **argv);
 int main_pcidetach(int argc, char **argv);
 int main_pciattach(int argc, char **argv);

tools/libxl/xl_cmdimpl.c

@@ -1654,6 +1654,52 @@ int main_console(int argc, char **argv)
     return 1;
 }
 
+static int vncviewer(const char *domain_spec, int autopass)
+{
+    find_domain(domain_spec);
+    libxl_vncviewer_exec(&ctx, domid, autopass);
+    fprintf(stderr, "Unable to execute vncviewer\n");
+    return 1;
+}
+
+int main_vncviewer(int argc, char **argv)
+{
+    static const struct option long_options[] = {
+        {"autopass", 0, 0, 'a'},
+        {"vncviewer-autopass", 0, 0, 'a'},
+        {"help", 0, 0, 'h'},
+        {0, 0, 0, 0}
+    };
+    int opt, autopass = 0;
+
+    while (1) {
+        opt = getopt_long(argc, argv, "ah", long_options, NULL);
+        if (opt == -1)
+            break;
+
+        switch (opt) {
+        case 'a':
+            autopass = 1;
+            break;
+        case 'h':
+            help("vncviewer");
+            exit(0);
+        default:
+            fprintf(stderr, "option not supported\n");
+            break;
+        }
+    }
+
+    if (argc - optind != 1) {
+        help("vncviewer");
+        exit(2);
+    }
+
+    if (vncviewer(argv[optind], autopass))
+        exit(1);
+    exit(0);
+}
+
 void pcilist(char *dom)
 {
     libxl_device_pci *pcidevs;

tools/libxl/xl_cmdtable.c

@@ -83,6 +83,14 @@ struct cmd_spec cmd_table[] = {
       "Attach to domain's console",
       "<Domain>",
     },
+    { "vncviewer",
+      &main_vncviewer,
+      "Attach to domain's VNC server.",
+      "[options] <Domain>\n"
+      "--autopass               Pass VNC password to viewer via stdin and\n"
+      "                         -autopass\n"
+      "--vncviewer-autopass     (consistency alias for --autopass)"
+    },
     { "save",
       &main_save,
       "Save a domain state to restore later",