libvirtd: new config-file option: unix_sock_dir

Before this change, the unix socket directory was hard-coded
to be e.g., /var/run/libvirt for euid==0 and ~/.libvirt otherwise.
With this change, you may now specify that directory in libvirtd's
config file via a line like this: unix_sock_dir = "/var/run/libvirt".
This is essential for running tests that do not impinge on any
existing libvirtd process, and in running tests in parallel.
* qemud/libvirtd.conf (unix_sock_dir): Add comment and example.
* qemud/qemud.h (struct qemud_server) [logDir]: Change type
from char[PATH_MAX] to char*.
* qemud/qemud.c (unix_sock_dir): New global
(remoteReadConfigFile): Set the global.
(qemudInitPaths): Use the global, unix_sock_dir, if non-NULL.
One minor improvement: unlink both sockets or none, never
just one of them.
(qemudCleanup): Free logDir.
(main): Use the new global rather than hard-coding "/run/libvirt".
* qemud/libvirtd.aug (sock_acl_entry): Add "unix_sock_dir".

ChangeLog

+Mon Feb 9 17:26:07 +0100 2009 Jim Meyering <meyering@redhat.com>
+
+	libvirtd: new config-file option: unix_sock_dir
+	Before this change, the unix socket directory was hard-coded
+	to be e.g., /var/run/libvirt for euid==0 and ~/.libvirt otherwise.
+	With this change, you may now specify that directory in libvirtd's
+	config file via a line like this: unix_sock_dir = "/var/run/libvirt".
+	This is essential for running tests that do not impinge on any
+	existing libvirtd process, and in running tests in parallel.
+	* qemud/libvirtd.conf (unix_sock_dir): Add comment and example.
+	* qemud/qemud.h (struct qemud_server) [logDir]: Change type
+	from char[PATH_MAX] to char*.
+	* qemud/qemud.c (unix_sock_dir): New global
+	(remoteReadConfigFile): Set the global.
+	(qemudInitPaths): Use the global, unix_sock_dir, if non-NULL.
+	One minor improvement: unlink both sockets or none, never
+	just one of them.
+	(qemudCleanup): Free logDir.
+	(main): Use the new global rather than hard-coding "/run/libvirt".
+	* qemud/libvirtd.aug (sock_acl_entry): Add "unix_sock_dir".
+
 Mon Feb 9 10:13:28 +0100 2009 Jim Meyering <meyering@redhat.com>
 
 	don't print uninitialized in debug diagnostic

qemud/libvirtd.aug

@@ -35,6 +35,7 @@ module Libvirtd =
    let sock_acl_entry = str_entry "unix_sock_group"
                       | str_entry "unix_sock_ro_perms"
                       | str_entry "unix_sock_rw_perms"
+                      | str_entry "unix_sock_dir"
 
    let authentication_entry = str_entry "auth_unix_ro"
                             | str_entry "auth_unix_rw"
@@ -79,4 +80,3 @@ module Libvirtd =
               . Util.stdexcl
 
    let xfm = transform lns filter
-

qemud/libvirtd.conf

@@ -97,7 +97,8 @@
 # control then you may want to relax this to:
 #unix_sock_rw_perms = "0770"
 
-
+# Set the name of the directory in which sockets will be found/created.
+#unix_sock_dir = "/var/run/libvirt"
 
 #################################################################
 #

qemud/qemud.c

@@ -51,6 +51,8 @@
 #include "libvirt_internal.h"
 #include "virterror_internal.h"
 
+#define VIR_FROM_THIS VIR_FROM_QEMU
+
 #include "qemud.h"
 #include "util.h"
 #include "remote_internal.h"
@@ -136,6 +138,8 @@ static char *listen_addr  = (char *) LIBVIRTD_LISTEN_ADDR;
 static char *tls_port = (char *) LIBVIRTD_TLS_PORT;
 static char *tcp_port = (char *) LIBVIRTD_TCP_PORT;
 
+static char *unix_sock_dir = NULL;
+
 #if HAVE_POLKIT
 static int auth_unix_rw = REMOTE_AUTH_POLKIT;
 static int auth_unix_ro = REMOTE_AUTH_POLKIT;
@@ -712,46 +716,75 @@ static int qemudInitPaths(struct qemud_server *server,
                           int maxlen)
 {
     uid_t uid = geteuid();
+    char *sock_dir;
+    char *dir_prefix = NULL;
+    int ret = -1;
+    char *sock_dir_prefix = NULL;
+
+    if (unix_sock_dir)
+        sock_dir = unix_sock_dir;
+    else {
+        sock_dir = sockname;
+        if (uid == SYSTEM_UID) {
+            dir_prefix = strdup (LOCAL_STATE_DIR);
+            if (dir_prefix == NULL) {
+                virReportOOMError(NULL);
+                goto cleanup;
+            }
+            if (snprintf (sock_dir, maxlen, "%s/run/libvirt",
+                          dir_prefix) >= maxlen)
+                goto snprintf_error;
+        } else {
+            dir_prefix = virGetUserDirectory(NULL, uid);
+            if (dir_prefix == NULL) {
+                /* Do not diagnose here; virGetUserDirectory does that.  */
+                goto snprintf_error;
+            }
 
-    if (uid == SYSTEM_UID) {
-        if (snprintf (sockname, maxlen, "%s/run/libvirt/libvirt-sock",
-                      LOCAL_STATE_DIR) >= maxlen)
-            goto snprintf_error;
+            if (snprintf(sock_dir, maxlen, "%s/.libvirt", dir_prefix) >= maxlen)
+                goto snprintf_error;
+        }
+    }
 
-        unlink(sockname);
+    sock_dir_prefix = strdup (sock_dir);
+    if (!sock_dir_prefix) {
+        virReportOOMError(NULL);
+        goto cleanup;
+    }
 
-        if (snprintf (roSockname, maxlen, "%s/run/libvirt/libvirt-sock-ro",
-                      LOCAL_STATE_DIR) >= maxlen)
+    if (uid == SYSTEM_UID) {
+        if (snprintf (sockname, maxlen, "%s/libvirt-sock",
+                      sock_dir_prefix) >= maxlen
+            || (snprintf (roSockname, maxlen, "%s/libvirt-sock-ro",
+                          sock_dir_prefix) >= maxlen))
             goto snprintf_error;
-
+        unlink(sockname);
         unlink(roSockname);
-
-        if (snprintf(server->logDir, PATH_MAX, "%s/log/libvirt/", LOCAL_STATE_DIR) >= PATH_MAX)
-            goto snprintf_error;
     } else {
-        char *userdir = virGetUserDirectory(NULL, uid);
-        if (userdir == NULL) {
-            /* Do not diagnose here; virGetUserDirectory does that.  */
-            return -1;
-        }
-
-        if (snprintf(sockname, maxlen, "@%s/.libvirt/libvirt-sock", userdir) >= maxlen) {
-            VIR_FREE(userdir);
+        if (snprintf(sockname, maxlen, "@%s/libvirt-sock",
+                     sock_dir_prefix) >= maxlen)
             goto snprintf_error;
-        }
+    }
 
-        if (snprintf(server->logDir, PATH_MAX, "%s/.libvirt/log", userdir) >= PATH_MAX) {
-            VIR_FREE(userdir);
-            goto snprintf_error;
-        }
-        VIR_FREE(userdir);
-    } /* !remote */
+    if (uid == SYSTEM_UID)
+      server->logDir = strdup (LOCAL_STATE_DIR "/log/libvirt");
+    else
+      virAsprintf(&server->logDir, "%s/.libvirt/log", dir_prefix);
 
-    return 0;
+    if (server->logDir == NULL)
+        virReportOOMError(NULL);
+
+    ret = 0;
 
  snprintf_error:
-    VIR_ERROR("%s", _("Resulting path too long for buffer in qemudInitPaths()"));
-    return -1;
+    if (ret)
+        VIR_ERROR("%s",
+                  _("Resulting path too long for buffer in qemudInitPaths()"));
+
+ cleanup:
+    free (dir_prefix);
+    free (sock_dir_prefix);
+    return ret;
 }
 
 static struct qemud_server *qemudInitialize(int sigread) {
@@ -2208,6 +2241,7 @@ static void qemudCleanup(struct qemud_server *server) {
         free(sock);
         sock = next;
     }
+    free(server->logDir);
 
 #ifdef HAVE_SASL
     if (server->saslUsernameWhitelist) {
@@ -2556,6 +2590,8 @@ remoteReadConfigFile (struct qemud_server *server, const char *filename)
         unix_sock_rw_perms = NULL;
     }
 
+    GET_CONF_STR (conf, filename, unix_sock_dir);
+
     GET_CONF_INT (conf, filename, mdns_adv);
     GET_CONF_STR (conf, filename, mdns_name);
 
@@ -2846,11 +2882,10 @@ int main(int argc, char **argv) {
         goto error2;
 
     /* Change the group ownership of /var/run/libvirt to unix_sock_gid */
-    if (getuid() == 0) {
-        const char *sockdirname = LOCAL_STATE_DIR "/run/libvirt";
-
-        if (chown(sockdirname, -1, unix_sock_gid) < 0)
-            VIR_ERROR(_("Failed to change group ownership of %s"), sockdirname);
+    if (unix_sock_dir && geteuid() == 0) {
+        if (chown(unix_sock_dir, -1, unix_sock_gid) < 0)
+            VIR_ERROR(_("Failed to change group ownership of %s"),
+                      unix_sock_dir);
     }
 
     if (virEventAddHandleImpl(sigpipe[0],

qemud/qemud.h

 /*
  * qemud.h: daemon data structure definitions
  *
- * Copyright (C) 2006-2008 Red Hat, Inc.
+ * Copyright (C) 2006-2009 Red Hat, Inc.
  * Copyright (C) 2006 Daniel P. Berrange
  *
  * This library is free software; you can redistribute it and/or
@@ -181,7 +181,7 @@ struct qemud_server {
     struct qemud_client **clients;
 
     int sigread;
-    char logDir[PATH_MAX];
+    char *logDir;
     unsigned int shutdown : 1;
 #ifdef HAVE_AVAHI
     struct libvirtd_mdns *mdns;