[libvirt] [PATCH RFC 1/7] virprocess: Introduce virProcessSetupPrivateNS

[Michal Privoznik]

This part of code that LXC currently uses will be reused so move
to a generic function.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/libvirt_private.syms |  1 +
 src/lxc/lxc_controller.c | 18 +-----------------
 src/util/virprocess.c    | 24 ++++++++++++++++++++++++
 src/util/virprocess.h    |  2 ++
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index ac6a1e1..42650d1 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2246,6 +2246,7 @@ virProcessSetMaxMemLock;
 virProcessSetMaxProcesses;
 virProcessSetNamespaces;
 virProcessSetScheduler;
+virProcessSetupPrivateNS;
 virProcessTranslateStatus;
 virProcessWait;
 
diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
index 508bc3e..1bb868a 100644
--- a/src/lxc/lxc_controller.c
+++ b/src/lxc/lxc_controller.c
@@ -2092,8 +2092,6 @@ lxcCreateTty(virLXCControllerPtr ctrl, int *ttymaster,
 static int
 virLXCControllerSetupPrivateNS(void)
 {
-    int ret = -1;
-
     /*
      * If doing a chroot style setup, we need to prepare
      * a private /dev/pts for the child now, which they
@@ -2115,21 +2113,7 @@ virLXCControllerSetupPrivateNS(void)
      * marked as shared
      */
 
-    if (unshare(CLONE_NEWNS) < 0) {
-        virReportSystemError(errno, "%s",
-                             _("Cannot unshare mount namespace"));
-        goto cleanup;
-    }
-
-    if (mount("", "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) {
-        virReportSystemError(errno, "%s",
-                             _("Failed to switch root mount into slave mode"));
-        goto cleanup;
-    }
-
-    ret = 0;
- cleanup:
-    return ret;
+    return virProcessSetupPrivateNS();
 }
 
 
diff --git a/src/util/virprocess.c b/src/util/virprocess.c
index 718c4a2..94eacbd 100644
--- a/src/util/virprocess.c
+++ b/src/util/virprocess.c
@@ -28,6 +28,7 @@
 #include <stdlib.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <sys/mount.h>
 #if HAVE_SETRLIMIT
 # include <sys/time.h>
 # include <sys/resource.h>
@@ -1146,6 +1147,29 @@ virProcessRunInMountNamespace(pid_t pid,
 }
 
 
+int
+virProcessSetupPrivateNS(void)
+{
+    int ret = -1;
+
+    if (unshare(CLONE_NEWNS) < 0) {
+        virReportSystemError(errno, "%s",
+                             _("Cannot unshare mount namespace"));
+        goto cleanup;
+    }
+
+    if (mount("", "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) {
+        virReportSystemError(errno, "%s",
+                             _("Failed to switch root mount into slave mode"));
+        goto cleanup;
+    }
+
+    ret = 0;
+ cleanup:
+    return ret;
+}
+
+
 /**
  * virProcessExitWithStatus:
  * @status: raw status to be reproduced when this process dies
diff --git a/src/util/virprocess.h b/src/util/virprocess.h
index 04e9802..74656d9 100644
--- a/src/util/virprocess.h
+++ b/src/util/virprocess.h
@@ -90,6 +90,8 @@ int virProcessRunInMountNamespace(pid_t pid,
                                   virProcessNamespaceCallback cb,
                                   void *opaque);
 
+int virProcessSetupPrivateNS(void);
+
 int virProcessSetScheduler(pid_t pid,
                            virProcessSchedPolicy policy,
                            int priority);
-- 
2.8.4