[Xen-changelog] [xen-unstable] libxc: add ability to query OS interface for "fakeness"

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1291369007 0
# Node ID 79c2b469a9f8ed5f4cddca88aa58b8879a8ff210
# Parent  36b2cef7eb9c38bb8b2f82027a6cd1b1f1deb56e
libxc: add ability to query OS interface for "fakeness"

i.e. not running on a real hypervisor

Allows users of the library to adjust behaviour. I don't especially
like this violation of the abstraction but both oxenstored and xapi
use this to avoid difficult to simulate operations when running on the
simulator.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Signed-off-by: Ian Jackson <ian.jackson.citrix.com>
---
 tools/libxc/xc_linux.c     |    1 +
 tools/libxc/xc_minios.c    |    1 +
 tools/libxc/xc_netbsd.c    |    1 +
 tools/libxc/xc_private.c   |   13 +++++++++++++
 tools/libxc/xc_solaris.c   |    1 +
 tools/libxc/xenctrl.h      |    9 +++++++++
 tools/libxc/xenctrlosdep.h |    3 +++
 7 files changed, 29 insertions(+)

diff -r 36b2cef7eb9c -r 79c2b469a9f8 tools/libxc/xc_linux.c
--- a/tools/libxc/xc_linux.c    Fri Dec 03 09:36:47 2010 +0000
+++ b/tools/libxc/xc_linux.c    Fri Dec 03 09:36:47 2010 +0000
@@ -697,6 +697,7 @@ xc_osdep_info_t xc_osdep_info = {
 xc_osdep_info_t xc_osdep_info = {
     .name = "Linux Native OS interface",
     .init = &linux_osdep_init,
+    .fake = 0,
 };
 
 /*
diff -r 36b2cef7eb9c -r 79c2b469a9f8 tools/libxc/xc_minios.c
--- a/tools/libxc/xc_minios.c   Fri Dec 03 09:36:47 2010 +0000
+++ b/tools/libxc/xc_minios.c   Fri Dec 03 09:36:47 2010 +0000
@@ -549,6 +549,7 @@ xc_osdep_info_t xc_osdep_info = {
 xc_osdep_info_t xc_osdep_info = {
     .name = "Minios Native OS interface",
     .init = &minios_osdep_init,
+    .fake = 0,
 };
 
 /*
diff -r 36b2cef7eb9c -r 79c2b469a9f8 tools/libxc/xc_netbsd.c
--- a/tools/libxc/xc_netbsd.c   Fri Dec 03 09:36:47 2010 +0000
+++ b/tools/libxc/xc_netbsd.c   Fri Dec 03 09:36:47 2010 +0000
@@ -373,6 +373,7 @@ xc_osdep_info_t xc_osdep_info = {
 xc_osdep_info_t xc_osdep_info = {
     .name = "Netbsd Native OS interface",
     .init = &netbsd_osdep_init,
+    .fake = 0,
 };
 
 /*
diff -r 36b2cef7eb9c -r 79c2b469a9f8 tools/libxc/xc_private.c
--- a/tools/libxc/xc_private.c  Fri Dec 03 09:36:47 2010 +0000
+++ b/tools/libxc/xc_private.c  Fri Dec 03 09:36:47 2010 +0000
@@ -122,6 +122,19 @@ static int xc_interface_close_common(xc_
     return rc;
 }
 
+int xc_interface_is_fake(void)
+{
+    xc_osdep_info_t info;
+
+    if ( xc_osdep_get_info(NULL, &info) < 0 )
+        return -1;
+
+    /* Have a copy of info so can release the interface now. */
+    xc_osdep_put(&info);
+
+    return info.fake;
+}
+
 xc_interface *xc_interface_open(xentoollog_logger *logger,
                                 xentoollog_logger *dombuild_logger,
                                 unsigned open_flags)
diff -r 36b2cef7eb9c -r 79c2b469a9f8 tools/libxc/xc_solaris.c
--- a/tools/libxc/xc_solaris.c  Fri Dec 03 09:36:47 2010 +0000
+++ b/tools/libxc/xc_solaris.c  Fri Dec 03 09:36:47 2010 +0000
@@ -321,6 +321,7 @@ xc_osdep_info_t xc_osdep_info = {
 xc_osdep_info_t xc_osdep_info = {
     .name = "Solaris Native OS interface",
     .init = &solaris_osdep_init,
+    .fake = 0,
 };
 
 /*
diff -r 36b2cef7eb9c -r 79c2b469a9f8 tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h     Fri Dec 03 09:36:47 2010 +0000
+++ b/tools/libxc/xenctrl.h     Fri Dec 03 09:36:47 2010 +0000
@@ -158,6 +158,15 @@ enum xc_open_flags {
  * @return 0 on success, -1 otherwise.
  */
 int xc_interface_close(xc_interface *xch);
+
+/**
+ * Query the active OS interface (i.e. that which would be returned by
+ * xc_interface_open) to find out if it is fake (i.e. backends onto
+ * something other than an actual Xen hypervisor).
+ *
+ * @return 0 is "real", >0 if fake, -1 on error.
+ */
+int xc_interface_is_fake(void);
 
 /*
  * HYPERCALL SAFE MEMORY BUFFER
diff -r 36b2cef7eb9c -r 79c2b469a9f8 tools/libxc/xenctrlosdep.h
--- a/tools/libxc/xenctrlosdep.h        Fri Dec 03 09:36:47 2010 +0000
+++ b/tools/libxc/xenctrlosdep.h        Fri Dec 03 09:36:47 2010 +0000
@@ -122,6 +122,9 @@ struct xc_osdep_info
 
     /* Returns ops function. */
     xc_osdep_init_fn init;
+
+    /* True if this interface backs onto a fake Xen. */
+    int fake;
 };
 typedef struct xc_osdep_info xc_osdep_info_t;
 

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