[libvirt] [PATCH 3/5] util: Introduce virFileMoveMount

[Michal Privoznik]

This is a simple wrapper over mount(). However, not every system
out there is capable of moving a mount point. Therefore, instead
of having to deal with this fact in all the places of our code we
can have a simple wrapper and deal with this fact at just one
place.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/libvirt_private.syms |  1 +
 src/qemu/qemu_domain.c   | 22 +++-------------------
 src/util/virfile.c       | 28 ++++++++++++++++++++++++++++
 src/util/virfile.h       |  3 +++
 4 files changed, 35 insertions(+), 19 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index d02d23b35..70ed87b95 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1605,6 +1605,7 @@ virFileMakeParentPath;
 virFileMakePath;
 virFileMakePathWithMode;
 virFileMatchesNameSuffix;
+virFileMoveMount;
 virFileNBDDeviceAssociate;
 virFileOpenAs;
 virFileOpenTty;
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 473d0c1a2..8602f01c7 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -7332,7 +7332,6 @@ qemuDomainBuildNamespace(virQEMUDriverPtr driver,
                          virDomainObjPtr vm)
 {
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
-    const unsigned long mount_flags = MS_MOVE;
     char *devPath = NULL;
     char **devMountsPath = NULL, **devMountsSavePath = NULL;
     size_t ndevMountsPath = 0, i;
@@ -7376,13 +7375,8 @@ qemuDomainBuildNamespace(virQEMUDriverPtr driver,
             goto cleanup;
         }
 
-        if (mount(devMountsPath[i], devMountsSavePath[i],
-                  NULL, mount_flags, NULL) < 0) {
-            virReportSystemError(errno,
-                                 _("Unable to move %s mount"),
-                                 devMountsPath[i]);
+        if (virFileMoveMount(devMountsPath[i], devMountsSavePath[i]) < 0)
             goto cleanup;
-        }
     }
 
     if (qemuDomainSetupAllDisks(driver, vm, devPath) < 0)
@@ -7403,12 +7397,8 @@ qemuDomainBuildNamespace(virQEMUDriverPtr driver,
     if (qemuDomainSetupAllRNGs(driver, vm, devPath) < 0)
         goto cleanup;
 
-    if (mount(devPath, "/dev", NULL, mount_flags, NULL) < 0) {
-        virReportSystemError(errno,
-                             _("Failed to mount %s on /dev"),
-                             devPath);
+    if (virFileMoveMount(devPath, "/dev") < 0)
         goto cleanup;
-    }
 
     for (i = 0; i < ndevMountsPath; i++) {
         if (devMountsSavePath[i] == devPath)
@@ -7420,14 +7410,8 @@ qemuDomainBuildNamespace(virQEMUDriverPtr driver,
             goto cleanup;
         }
 
-        if (mount(devMountsSavePath[i], devMountsPath[i],
-                  NULL, mount_flags, NULL) < 0) {
-            virReportSystemError(errno,
-                                 _("Failed to mount %s on %s"),
-                                 devMountsSavePath[i],
-                                 devMountsPath[i]);
+        if (virFileMoveMount(devMountsSavePath[i], devMountsPath[i]) < 0)
             goto cleanup;
-        }
     }
 
     ret = 0;
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 99157be16..bf8099e34 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -3610,6 +3610,24 @@ virFileBindMountDevice(const char *src,
     return 0;
 }
 
+
+int
+virFileMoveMount(const char *src,
+                 const char *dst)
+{
+    const unsigned long mount_flags = MS_MOVE;
+
+    if (mount(src, dst, NULL, mount_flags, NULL) < 0) {
+        virReportSystemError(errno,
+                             _("Unable to move %s mount to %s"),
+                             src, dst);
+        return -1;
+    }
+
+    return 0;
+}
+
+
 #else /* !defined(__linux__) || !defined(HAVE_SYS_MOUNT_H) */
 
 int
@@ -3630,6 +3648,16 @@ virFileBindMountDevice(const char *src ATTRIBUTE_UNUSED,
                          _("mount is not supported on this platform."));
     return -1;
 }
+
+
+int
+virFileMoveMount(const char *src ATTRIBUTE_UNUSED,
+                 const char *dst ATTRIBUTE_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("mount move is not supported on this platform."));
+    return -1;
+}
 #endif /* !defined(__linux__) || !defined(HAVE_SYS_MOUNT_H) */
 
 
diff --git a/src/util/virfile.h b/src/util/virfile.h
index 571e5bdc8..0343acd5b 100644
--- a/src/util/virfile.h
+++ b/src/util/virfile.h
@@ -318,6 +318,9 @@ int virFileSetupDev(const char *path,
 int virFileBindMountDevice(const char *src,
                            const char *dst);
 
+int virFileMoveMount(const char *src,
+                     const char *dst);
+
 int virFileGetACLs(const char *file,
                    void **acl);
 
-- 
2.11.0