From 9d2ac5453e4d50c6f12b2f8a5078691fec60020b Mon Sep 17 00:00:00 2001
From: Jiri Denemark <jdenemar@redhat.com>
Date: Fri, 27 Apr 2012 15:50:22 +0200
Subject: [PATCH] qemu: Make sure qemu can access its directory in hugetlbfs

When libvirtd is started, we create "libvirt/qemu" directories under
hugetlbfs mount point. Only the "qemu" subdirectory is chowned to qemu
user and "libvirt" remains owned by root. If umask was too restrictive
when libvirtd started, qemu user may lose access to "qemu"
subdirectory. Let's explicitly grant search permissions to "libvirt"
directory for all users.
---
 src/libvirt_private.syms |  1 +
 src/qemu/qemu_driver.c   | 27 +++++++++++++++++----------
 src/util/virfile.c       | 37 +++++++++++++++++++++++++++++++++++++
 src/util/virfile.h       |  4 ++++
 4 files changed, 59 insertions(+), 10 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 025816ab1b..d4038b21f2 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1209,6 +1209,7 @@ virFileFclose;
 virFileFdopen;
 virFileRewrite;
 virFileTouch;
+virFileUpdatePerm;
 
 
 # virkeycode.h
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 349274b251..78899a4734 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -456,6 +456,8 @@ qemudStartup(int privileged) {
     int rc;
     virConnectPtr conn = NULL;
     char ebuf[1024];
+    char *membase = NULL;
+    char *mempath = NULL;
 
     if (VIR_ALLOC(qemu_driver) < 0)
         return -1;
@@ -660,23 +662,26 @@ qemudStartup(int privileged) {
      */
     if (qemu_driver->hugetlbfs_mount &&
         qemu_driver->hugetlbfs_mount[0] == '/') {
-        char *mempath = NULL;
-        if (virAsprintf(&mempath, "%s/libvirt/qemu", qemu_driver->hugetlbfs_mount) < 0)
+        if (virAsprintf(&membase, "%s/libvirt",
+                        qemu_driver->hugetlbfs_mount) < 0 ||
+            virAsprintf(&mempath, "%s/qemu", membase) < 0)
             goto out_of_memory;
 
         if (virFileMakePath(mempath) < 0) {
             virReportSystemError(errno,
                                  _("unable to create hugepage path %s"), mempath);
-            VIR_FREE(mempath);
             goto error;
         }
-        if (qemu_driver->privileged &&
-            chown(mempath, qemu_driver->user, qemu_driver->group) < 0) {
-            virReportSystemError(errno,
-                                 _("unable to set ownership on %s to %d:%d"),
-                                 mempath, qemu_driver->user, qemu_driver->group);
-            VIR_FREE(mempath);
-            goto error;
+        if (qemu_driver->privileged) {
+            if (virFileUpdatePerm(membase, 0, S_IXGRP | S_IXOTH) < 0)
+                goto error;
+            if (chown(mempath, qemu_driver->user, qemu_driver->group) < 0) {
+                virReportSystemError(errno,
+                                     _("unable to set ownership on %s to %d:%d"),
+                                     mempath, qemu_driver->user,
+                                     qemu_driver->group);
+                goto error;
+            }
         }
 
         qemu_driver->hugepage_path = mempath;
@@ -737,6 +742,8 @@ error:
         virConnectClose(conn);
     VIR_FREE(base);
     VIR_FREE(driverConf);
+    VIR_FREE(membase);
+    VIR_FREE(mempath);
     qemudShutdown();
     return -1;
 }
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 66160dc902..db3d737d96 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -437,3 +437,40 @@ int virFileTouch(const char *path, mode_t mode)
 
     return 0;
 }
+
+
+#define MODE_BITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
+
+int virFileUpdatePerm(const char *path,
+                      mode_t mode_remove,
+                      mode_t mode_add)
+{
+    struct stat sb;
+    mode_t mode;
+
+    if (mode_remove & ~MODE_BITS || mode_add & ~MODE_BITS) {
+        virFileError(VIR_ERR_INVALID_ARG, "%s", _("invalid mode"));
+        return -1;
+    }
+
+    if (stat(path, &sb) < 0) {
+        virReportSystemError(errno, _("cannot stat '%s'"), path);
+        return -1;
+    }
+
+    mode = sb.st_mode & MODE_BITS;
+
+    if ((mode & mode_remove) == 0 && (mode & mode_add) == mode_add)
+        return 0;
+
+    mode &= MODE_BITS ^ mode_remove;
+    mode |= mode_add;
+
+    if (chmod(path, mode) < 0) {
+        virReportSystemError(errno, _("cannot change permission of '%s'"),
+                             path);
+        return -1;
+    }
+
+    return 0;
+}
diff --git a/src/util/virfile.h b/src/util/virfile.h
index 184677c597..05f50480e6 100644
--- a/src/util/virfile.h
+++ b/src/util/virfile.h
@@ -83,4 +83,8 @@ int virFileRewrite(const char *path,
 
 int virFileTouch(const char *path, mode_t mode);
 
+int virFileUpdatePerm(const char *path,
+                      mode_t mode_remove,
+                      mode_t mode_add);
+
 #endif /* __VIR_FILES_H */