debug: log libxc output to /var/log/xen/libxc.log

sledge hammer patch ;)
---
 tools/libxc/xc_dom_compat_linux.c |    2 ++
 tools/libxc/xc_hvm_build.c        |    2 ++
 tools/libxc/xc_linux_build.c      |    2 ++
 tools/libxc/xc_private.c          |    9 +++++++++
 tools/libxc/xc_private.h          |   11 +++++++----
 5 files changed, 22 insertions(+), 4 deletions(-)

Index: build-64-release304-13087/tools/libxc/xc_hvm_build.c
===================================================================
--- build-64-release304-13087.orig/tools/libxc/xc_hvm_build.c
+++ build-64-release304-13087/tools/libxc/xc_hvm_build.c
@@ -310,6 +310,8 @@ static int xc_hvm_build_internal(int xc_
     vcpu_guest_context_t ctxt;
     int rc;
 
+    log_kraxel();
+
     if ( (image == NULL) || (image_size == 0) )
     {
         ERROR("Image required");
Index: build-64-release304-13087/tools/libxc/xc_linux_build.c
===================================================================
--- build-64-release304-13087.orig/tools/libxc/xc_linux_build.c
+++ build-64-release304-13087/tools/libxc/xc_linux_build.c
@@ -1099,6 +1099,8 @@ static int xc_linux_build_internal(int x
     unsigned long vstartinfo_start, vkern_entry, vstack_start;
     uint32_t      features_bitmap[XENFEAT_NR_SUBMAPS] = { 0, };
 
+    log_kraxel();
+
     if ( features != NULL )
     {
         if ( !parse_features(features, features_bitmap, NULL) )
Index: build-64-release304-13087/tools/libxc/xc_private.c
===================================================================
--- build-64-release304-13087.orig/tools/libxc/xc_private.c
+++ build-64-release304-13087/tools/libxc/xc_private.c
@@ -88,6 +88,15 @@ void xc_set_error(int code, const char *
         error_handler(&last_error);
 }
 
+FILE *kraxel;
+
+void log_kraxel(void)
+{
+	kraxel = fopen("/var/log/xen/libxc.log", "a");
+	setvbuf(kraxel, NULL, _IONBF, 0);
+	fprintf(kraxel, "--- started ---\n");
+}
+
 int lock_pages(void *addr, size_t len)
 {
       int e = 0;
Index: build-64-release304-13087/tools/libxc/xc_private.h
===================================================================
--- build-64-release304-13087.orig/tools/libxc/xc_private.h
+++ build-64-release304-13087/tools/libxc/xc_private.h
@@ -39,22 +39,25 @@
 
 #define DEBUG    1
 #define INFO     1
-#define PROGRESS 0
+#define PROGRESS 1
+
+extern FILE *kraxel;
+void log_kraxel(void);
 
 #if INFO
-#define IPRINTF(_f, _a...) printf(_f , ## _a)
+#define IPRINTF(_f, _a...) fprintf(kraxel, _f , ## _a)
 #else
 #define IPRINTF(_f, _a...) ((void)0)
 #endif
 
 #if DEBUG
-#define DPRINTF(_f, _a...) fprintf(stderr, _f , ## _a)
+#define DPRINTF(_f, _a...) fprintf(kraxel, _f , ## _a)
 #else
 #define DPRINTF(_f, _a...) ((void)0)
 #endif
 
 #if PROGRESS
-#define PPRINTF(_f, _a...) fprintf(stderr, _f , ## _a)
+#define PPRINTF(_f, _a...) fprintf(kraxel, _f , ## _a)
 #else
 #define PPRINTF(_f, _a...)
 #endif
Index: build-64-release304-13087/tools/libxc/xc_dom_compat_linux.c
===================================================================
--- build-64-release304-13087.orig/tools/libxc/xc_dom_compat_linux.c
+++ build-64-release304-13087/tools/libxc/xc_dom_compat_linux.c
@@ -74,6 +74,7 @@ int xc_linux_build_mem(int xc_handle, ui
     int rc;
 
     xc_dom_loginit();
+    log_kraxel();
     dom = xc_dom_allocate(cmdline, features);
     if (0 != (rc = xc_dom_kernel_mem(dom, image_buffer, image_size)))
 	goto out;
@@ -106,6 +107,7 @@ int xc_linux_build(int xc_handle, uint32
     int rc;
 
     xc_dom_loginit();
+    log_kraxel();
     dom = xc_dom_allocate(cmdline, features);
     if (0 != (rc = xc_dom_kernel_file(dom, image_name)))
 	goto out;