qemu: configurable remote display port boundaries

The defines QEMU_REMOTE_PORT_MIN and QEMU_REMOTE_PORT_MAX were used to
find free port when starting domains. As this was hard-coded to the
same ports as default VNC servers, there were races with these other
programs. This patch includes the possibility to change the default
starting port as well as the maximum port (mostly for completeness) in
qemu config file.

Support for two new config options in qemu.conf is added:
 - remote_port_min (defaults to QEMU_REMOTE_PORT_MIN and
   must be >= than this value)
 - remote_port_max (defaults to QEMU_REMOTE_PORT_MAX and
   must be <= than this value)

diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug
index 683aadb908d7aa520b2c7bd5f011739b4b053860..b95d751e622a4d61ca4e393099f03790aa2b5ef6 100644 (file)
--- a/src/qemu/libvirtd_qemu.aug
+++ b/src/qemu/libvirtd_qemu.aug
@@ -39,6 +39,9 @@ module Libvirtd_qemu =
                  | str_entry  "spice_tls_x509_cert_dir"
                  | str_entry "spice_password"
 
+   let remote_display_entry = int_entry "remote_display_port_min"
+                 | int_entry "remote_display_port_max"
+
    let security_entry = str_entry "security_driver"
                  | bool_entry "security_default_confined"
                  | bool_entry "security_require_confined"
@@ -72,6 +75,7 @@ module Libvirtd_qemu =
    (* Each enty in the config is one of the following three ... *)
    let entry = vnc_entry
              | spice_entry
+             | remote_display_entry
              | security_entry
              | save_entry
              | process_entry

diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf
index 257a477cccbc4baadde9b38fd535ff883f2ecdda..fb22b7cd8916daf63c64f0280df332a73964a524 100644 (file)
--- a/src/qemu/qemu.conf
+++ b/src/qemu/qemu.conf
@@ -140,6 +140,20 @@
 #spice_password = "XYZ12345"
 
 
+# Override the port for creating both VNC and SPICE sessions (min).
+# This defaults to 5900 and increases for consecutive sessions
+# or when ports are occupied, until it hits the maximum.
+#
+# Minimum must be greater than or equal to 5900 as lower number would
+# result into negative vnc display number.
+#
+# Maximum must be less than 65536, because higher numbers do not make
+# sense as a port number.
+#
+#remote_display_port_min = 5900
+#remote_display_port_max = 65535
+
+
 # The default security driver is SELinux. If SELinux is disabled
 # on the host, then the security driver will automatically disable
 # itself. If you wish to disable QEMU SELinux security driver while

diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
index 14afd9bbad742bc838351667cfd982ffee1610db..7c5e8ddfd4873d4c21f5c67183dbed1ffba730d0 100644 (file)
--- a/src/qemu/qemu_command.h
+++ b/src/qemu/qemu_command.h
@@ -37,6 +37,13 @@
 # define QEMU_VIRTIO_SERIAL_PREFIX "virtio-serial"
 # define QEMU_FSDEV_HOST_PREFIX "fsdev-"
 
+/* These are only defaults, they can be changed now in qemu.conf and
+ * explicitely specified port is checked against these two (makes
+ * sense to limit the values).
+ *
+ * This limitation is mentioned in qemu.conf, so bear in mind that the
+ * configuration file should reflect any changes made to these values.
+ */
 # define QEMU_REMOTE_PORT_MIN  5900
 # define QEMU_REMOTE_PORT_MAX  65535
 

diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index ed6d8326db300e50bc12931a3869d4e047e11f65..e9e15c50292d416ee542b0f6d57fd60978d311f8 100644 (file)
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -1,7 +1,7 @@
 /*
  * qemu_conf.c: QEMU configuration management
  *
- * Copyright (C) 2006-2011 Red Hat, Inc.
+ * Copyright (C) 2006-2012 Red Hat, Inc.
  * Copyright (C) 2006 Daniel P. Berrange
  *
  * This library is free software; you can redistribute it and/or
@@ -38,6 +38,7 @@
 
 #include "virterror_internal.h"
 #include "qemu_conf.h"
+#include "qemu_command.h"
 #include "qemu_capabilities.h"
 #include "qemu_bridge_filter.h"
 #include "uuid.h"
@@ -89,6 +90,10 @@ int qemudLoadDriverConfig(struct qemud_driver *driver,
         virReportOOMError();
         return -1;
     }
+
+    driver->remotePortMin = QEMU_REMOTE_PORT_MIN;
+    driver->remotePortMax = QEMU_REMOTE_PORT_MAX;
+
     if (!(driver->vncTLSx509certdir = strdup(SYSCONFDIR "/pki/libvirt-vnc"))) {
         virReportOOMError();
         return -1;
@@ -295,6 +300,47 @@ int qemudLoadDriverConfig(struct qemud_driver *driver,
         }
     }
 
+    p = virConfGetValue (conf, "remote_display_port_min");
+    CHECK_TYPE ("remote_display_port_min", VIR_CONF_LONG);
+    if (p) {
+        if (p->l < QEMU_REMOTE_PORT_MIN) {
+            /* if the port is too low, we can't get the display name
+             * to tell to vnc (usually subtract 5900, e.g. localhost:1
+             * for port 5901) */
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("%s: remote_display_port_min: port must be greater than or equal to %d"),
+                            filename, QEMU_REMOTE_PORT_MIN);
+            virConfFree(conf);
+            return -1;
+        }
+        driver->remotePortMin = p->l;
+    }
+
+    p = virConfGetValue (conf, "remote_display_port_max");
+    CHECK_TYPE ("remote_display_port_max", VIR_CONF_LONG);
+    if (p) {
+        if (p->l > QEMU_REMOTE_PORT_MAX ||
+            p->l < driver->remotePortMin) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                            _("%s: remote_display_port_max: port must be between the minimal port and %d"),
+                            filename, QEMU_REMOTE_PORT_MAX);
+            virConfFree(conf);
+            return -1;
+        }
+        /* increasing the value by 1 makes all the loops going through
+        the bitmap (i = remotePortMin; i < remotePortMax; i++), work as
+        expected. */
+        driver->remotePortMax = p->l + 1;
+    }
+
+    if (driver->remotePortMin > driver->remotePortMax) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                        _("%s: remote_display_port_min: min port must not be greater than max port"),
+                        filename);
+        virConfFree(conf);
+        return -1;
+    }
+
     p = virConfGetValue (conf, "user");
     CHECK_TYPE ("user", VIR_CONF_STRING);
     if (!(user = strdup(p && p->str ? p->str : QEMU_USER))) {

diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index cfebe35a69902f241c8ba560be3df6a600500f9a..ac285f6ed46d8e6fb3d2e4ed4b9b275d12edd5dc 100644 (file)
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -95,6 +95,8 @@ struct qemud_driver {
     char *spiceTLSx509certdir;
     char *spiceListen;
     char *spicePassword;
+    int remotePortMin;
+    int remotePortMax;
     char *hugetlbfs_mount;
     char *hugepage_path;
 

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 00eb4447664eaf36a954e93775e3844e5f703615..f94ddb18ff6fb313acdd67977e9aa31e97c6eae9 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -590,11 +590,6 @@ qemudStartup(int privileged) {
     if (!qemu_driver->domainEventState)
         goto error;
 
-    /* Allocate bitmap for vnc port reservation */
-    if ((qemu_driver->reservedRemotePorts =
-         virBitmapAlloc(QEMU_REMOTE_PORT_MAX - QEMU_REMOTE_PORT_MIN)) == NULL)
-        goto out_of_memory;
-
     /* read the host sysinfo */
     if (privileged)
         qemu_driver->hostsysinfo = virSysinfoRead();
@@ -720,6 +715,13 @@ qemudStartup(int privileged) {
     }
     VIR_FREE(driverConf);
 
+    /* Allocate bitmap for remote display port reservations. We cannot
+     * do this before the config is loaded properly, since the port
+     * numbers are configurable now */
+    if ((qemu_driver->reservedRemotePorts =
+         virBitmapAlloc(qemu_driver->remotePortMax - qemu_driver->remotePortMin)) == NULL)
+        goto out_of_memory;
+
     /* We should always at least have the 'nop' manager, so
      * NULLs here are a fatal error
      */

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 4a13f6664f1b8ce0d437b948b0bda10073bfcf92..4463134be4d0f054570c7feefe520258c5273f52 100644 (file)
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2454,15 +2454,15 @@ static int qemuProcessNextFreePort(struct qemud_driver *driver,
 {
     int i;
 
-    for (i = startPort ; i < QEMU_REMOTE_PORT_MAX; i++) {
+    for (i = startPort ; i < driver->remotePortMax; i++) {
         int fd;
         int reuse = 1;
         struct sockaddr_in addr;
         bool used = false;
 
         if (virBitmapGetBit(driver->reservedRemotePorts,
-                            i - QEMU_REMOTE_PORT_MIN, &used) < 0)
-            VIR_DEBUG("virBitmapGetBit failed on bit %d", i - QEMU_REMOTE_PORT_MIN);
+                            i - driver->remotePortMin, &used) < 0)
+            VIR_DEBUG("virBitmapGetBit failed on bit %d", i - driver->remotePortMin);
 
         if (used)
             continue;
@@ -2484,9 +2484,9 @@ static int qemuProcessNextFreePort(struct qemud_driver *driver,
             VIR_FORCE_CLOSE(fd);
             /* Add port to bitmap of reserved ports */
             if (virBitmapSetBit(driver->reservedRemotePorts,
-                                i - QEMU_REMOTE_PORT_MIN) < 0) {
+                                i - driver->remotePortMin) < 0) {
                 VIR_DEBUG("virBitmapSetBit failed on bit %d",
-                          i - QEMU_REMOTE_PORT_MIN);
+                          i - driver->remotePortMin);
             }
             return i;
         }
@@ -2507,11 +2507,11 @@ static void
 qemuProcessReturnPort(struct qemud_driver *driver,
                       int port)
 {
-    if (port < QEMU_REMOTE_PORT_MIN)
+    if (port < driver->remotePortMin)
         return;
 
     if (virBitmapClearBit(driver->reservedRemotePorts,
-                          port - QEMU_REMOTE_PORT_MIN) < 0)
+                          port - driver->remotePortMin) < 0)
         VIR_DEBUG("Could not mark port %d as unused", port);
 }
 

diff --git a/src/qemu/test_libvirtd_qemu.aug.in b/src/qemu/test_libvirtd_qemu.aug.in
index 959f2501a5275875cc0c4f8c2a5212c836780afc..eac5882d8480aee5280eee0e67df35bac315e4b2 100644 (file)
--- a/src/qemu/test_libvirtd_qemu.aug.in
+++ b/src/qemu/test_libvirtd_qemu.aug.in
@@ -15,6 +15,8 @@ module Test_libvirtd_qemu =
 { "spice_tls" = "1" }
 { "spice_tls_x509_cert_dir" = "/etc/pki/libvirt-spice" }
 { "spice_password" = "XYZ12345" }
+{ "remote_display_port_min" = "5900" }
+{ "remote_display_port_max" = "65535" }
 { "security_driver" = "selinux" }
 { "security_default_confined" = "1" }
 { "security_require_confined" = "1" }