[PATCH,v7]: xl: randomly generate UUID's

* [PATCH,v7]: xl: randomly generate UUID's
@ 2010-09-02 14:29 Gianni Tedesco
  2010-09-02 15:53 ` Christoph Egger
  2010-09-06  9:54 ` Ian Campbell
  0 siblings, 2 replies; 6+ messages in thread
From: Gianni Tedesco @ 2010-09-02 14:29 UTC (permalink / raw)
  To: Xen Devel; +Cc: Christoph Egger, Ian Jackson, Stefano Stabellini

Changes since v6:
 - Non-constify libxl_uuid_bytearray() so that language bindings can use it
   to set a UUID.
 - Convert ocaml bindings to new API
 - Is this patch cursed or what?
Changes since v5:
 - There was an error caused due to missing change so the check for bad
   parsing of a "uuid" config option did not lead to error message and exit
   as I had stated in v4 announcement. Phew, sorry for the noise
Changes since v4:
 - Really fix it for NetBSD? Define our own structure which is a byte
   array. Only use uuid_is_nul and uuid_create which should be safe for
   our portability purposes. Previous attempt at portability wrapper was
   just wrong minded.
 - Remove uuid_to_string since our approach is to use a couple of macros
   for this
 - License under LGPL in line with rest of libxl
Changes since v3:
 - Fix LIBXL_UUID_BYTES on NetBSD. Note that the code assumes
   uint8_t[16] to always be interchangeable with libxl_uuid_t.
 - Return error messages when uuid_parse fails, spotted by Owen Smith
 - Implement "uuid" parameter in xl and exit with an error if parse
   fails
Changes since v2:
 - Re-based to remove orthogonal concern of UUID string formatting fixed
   in 22001:0b6f82eaaea9 "xl: make libxl_uuid2string internal to libxenlight"
 - Incorporated Christoph Egger's suggestions

------8<---------------------------------------------------------------
This patch converts xl to randomly generate UUID's rather than using a
dodgy time-seeded PRNG. I have ignored various suggestions so far on
auto-generation of MAC addresses and left it as a topic for a future
patch to solve. In other words the behaviour stays the same it's just
using a true random source. This patch also implements the "uuid" config
file parameter in xl.

Signed-off-by: Gianni Tedesco <gianni.tedesco@citrix.com>

diff -r 573ddf5cc145 tools/libxl/Makefile

--- a/tools/libxl/Makefile	Tue Aug 31 19:16:23 2010 +0100
+++ b/tools/libxl/Makefile	Thu Sep 02 15:29:01 2010 +0100
@@ -16,6 +16,9 @@ CFLAGS += -I. -fPIC
 CFLAGS += $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest) $(CFLAGS_libxenstore) $(CFLAGS_libblktapctl)
 
 LIBS = $(LDLIBS_libxenctrl) $(LDLIBS_libxenguest) $(LDLIBS_libxenstore) $(LDLIBS_libblktapctl) $(UTIL_LIBS)
+ifeq ($(CONFIG_Linux),y)
+LIBS += -luuid
+endif
 
 LIBXL_OBJS-y = osdeps.o libxl_paths.o libxl_bootloader.o
 ifeq ($(LIBXL_BLKTAP),y)
diff -r 573ddf5cc145 tools/libxl/libxl.c
--- a/tools/libxl/libxl.c	Tue Aug 31 19:16:23 2010 +0100
+++ b/tools/libxl/libxl.c	Thu Sep 02 15:29:01 2010 +0100
@@ -131,7 +131,7 @@ int libxl_domain_make(libxl_ctx *ctx, li
     *domid = -1;
 
     /* Ultimately, handle is an array of 16 uint8_t, same as uuid */
-    memcpy(handle, info->uuid, sizeof(xen_domain_handle_t));
+    libxl_uuid_copy((libxl_uuid *)handle, &info->uuid);
 
     ret = xc_domain_create(ctx->xch, info->ssidref, handle, flags, domid);
     if (ret < 0) {
@@ -1506,8 +1506,8 @@ static int libxl_create_stubdom(libxl_ct
     memset(&c_info, 0x00, sizeof(libxl_domain_create_info));
     c_info.hvm = 0;
     c_info.name = libxl_sprintf(&gc, "%s-dm", _libxl_domid_to_name(&gc, info->domid));
-    for (i = 0; i < 16; i++)
-        c_info.uuid[i] = info->uuid[i];
+
+    libxl_uuid_copy(&c_info.uuid, &info->uuid);
 
     memset(&b_info, 0x00, sizeof(libxl_domain_build_info));
     b_info.max_vcpus = 1;
diff -r 573ddf5cc145 tools/libxl/libxl.h
--- a/tools/libxl/libxl.h	Tue Aug 31 19:16:23 2010 +0100
+++ b/tools/libxl/libxl.h	Thu Sep 02 15:29:01 2010 +0100
@@ -131,13 +131,7 @@
 #include <xs.h>
 #include <sys/wait.h> /* for pid_t */
 
-typedef uint8_t libxl_uuid[16];
-#define LIBXL_UUID_FMT "%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
-#define LIBXL_UUID_BYTES(uuid) uuid[0], uuid[1], uuid[2], uuid[3], \
-            uuid[4], uuid[5], uuid[6], uuid[7], \
-            uuid[8], uuid[9], uuid[10], uuid[11], \
-            uuid[12], uuid[13], uuid[14], uuid[15] \
-
+#include "libxl_uuid.h"
 
 typedef uint8_t libxl_mac[6];
 
diff -r 573ddf5cc145 tools/libxl/libxl_uuid.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/libxl/libxl_uuid.h	Thu Sep 02 15:29:01 2010 +0100
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2008,2010 Citrix Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ */
+
+#ifndef __LIBXL_UUID_H__
+#define __LIBXL_UUID_H__
+
+#define LIBXL_UUID_FMT "%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
+#define LIBXL__UUID_BYTES(uuid) uuid[0], uuid[1], uuid[2], uuid[3], \
+                                uuid[4], uuid[5], uuid[6], uuid[7], \
+                                uuid[8], uuid[9], uuid[10], uuid[11], \
+                                uuid[12], uuid[13], uuid[14], uuid[15]
+
+#if defined(__linux__)
+
+#include <uuid/uuid.h>
+
+typedef struct {
+    uuid_t uuid;
+} libxl_uuid;
+
+#define LIBXL_UUID_BYTES(arg) LIBXL__UUID_BYTES(((uint8_t *)arg.uuid))
+
+static inline int libxl_uuid_is_nil(libxl_uuid *uuid)
+{
+     return uuid_is_null(uuid->uuid);
+}
+
+static inline void libxl_uuid_generate(libxl_uuid *uuid)
+{
+     uuid_generate(uuid->uuid);
+}
+
+static inline int libxl_uuid_from_string(libxl_uuid *uuid, const char *in)
+{
+     return uuid_parse(in, uuid->uuid);
+}
+
+static inline void libxl_uuid_copy(libxl_uuid *dst, libxl_uuid *src)
+{
+     uuid_copy(dst->uuid, src->uuid);
+}
+
+static inline void libxl_uuid_clear(libxl_uuid *uuid)
+{
+     uuid_clear(uuid->uuid);
+}
+
+static inline int libxl_uuid_compare(libxl_uuid *uuid1, libxl_uuid *uuid2)
+{
+     return uuid_compare(uuid1->uuid, uuid2->uuid);
+}
+
+static inline uint8_t *libxl_uuid_bytearray(libxl_uuid *uuid)
+{
+    return uuid->uuid;
+}
+
+#elif defined(__NetBSD__)
+
+#include <uuid.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+#define LIBXL_UUID_BYTES(arg) LIBXL__UUID_BYTES(arg.uuid)
+
+typedef struct {
+    uint8_t uuid[16];
+} libxl_uuid;
+
+static inline int libxl_uuid_is_nil(libxl_uuid *uuid)
+{
+    uint32_t status;
+    return uuid_is_nil((uuid_t *)uuid->uuid, &status);
+}
+
+static inline void libxl_uuid_generate(libxl_uuid *uuid)
+{
+    uint32_t status;
+    uuid_create((uuid_t *)uuid->uuid, &status);
+    assert(status == uuid_s_ok);
+}
+
+#define LIBXL__UUID_PTRS(uuid) &uuid[0], &uuid[1], &uuid[2], &uuid[3], \
+                               &uuid[4], &uuid[5], &uuid[6], &uuid[7], \
+                               &uuid[8], &uuid[9], &uuid[10],&uuid[11], \
+                               &uuid[12],&uuid[13],&uuid[14],&uuid[15]
+static inline int libxl_uuid_from_string(libxl_uuid *uuid, const char *in)
+{
+    if ( sscanf(in, LIBXL_UUID_FMT, LIBXL__UUID_PTRS(uuid->uuid)) != sizeof(uuid->uuid) )
+        return -1;
+    return 0;
+}
+#undef LIBXL__UUID_PTRS
+
+static inline void libxl_uuid_copy(libxl_uuid *dst, libxl_uuid *src)
+{
+     memcpy(dst->uuid, src->uuid, sizeof(dst->uuid));
+}
+
+static inline void libxl_uuid_clear(libxl_uuid *uuid)
+{
+     memset(uuid->uuid, 0, sizeof(uuid->uuid));
+}
+
+static inline int libxl_uuid_compare(libxl_uuid *uuid1, libxl_uuid *uuid2)
+{
+     return memcmp(uuid1->uuid, uuid2->uuid, sizeof(uuid1->uuid));
+}
+
+static inline uint8_t *libxl_uuid_bytearray(libxl_uuid *uuid)
+{
+    return uuid->uuid;
+}
+
+#else
+
+#error "Please update libxl_uuid.h for your OS"
+
+#endif
+
+#endif /* __LIBXL_UUID_H__ */
diff -r 573ddf5cc145 tools/libxl/xl.c
--- a/tools/libxl/xl.c	Tue Aug 31 19:16:23 2010 +0100
+++ b/tools/libxl/xl.c	Thu Sep 02 15:29:01 2010 +0100
@@ -74,8 +74,6 @@ int main(int argc, char **argv)
     argc -= optind;
     optind = 1;
 
-    srand(time(0));
-
     cspec = cmdtable_lookup(cmd);
     if (cspec)
         ret = cspec->cmd_impl(argc, argv);
diff -r 573ddf5cc145 tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c	Tue Aug 31 19:16:23 2010 +0100
+++ b/tools/libxl/xl_cmdimpl.c	Thu Sep 02 15:29:01 2010 +0100
@@ -286,19 +286,12 @@ static void init_build_info(libxl_domain
     }
 }
 
-static void random_uuid(libxl_uuid *uuid)
-{
-    int i;
-    for (i = 0; i < 16; i++)
-        (*uuid)[i] = rand();
-}
-
 static void init_dm_info(libxl_device_model_info *dm_info,
         libxl_domain_create_info *c_info, libxl_domain_build_info *b_info)
 {
     memset(dm_info, '\0', sizeof(*dm_info));
 
-    random_uuid(&dm_info->uuid);
+    libxl_uuid_generate(&dm_info->uuid);
 
     dm_info->dom_name = c_info->name;
     dm_info->device_model = "qemu-dm";
@@ -325,6 +318,11 @@ static void init_dm_info(libxl_device_mo
 
 static void init_nic_info(libxl_device_nic *nic_info, int devnum)
 {
+    const uint8_t *r;
+    libxl_uuid uuid;
+
+    libxl_uuid_generate(&uuid);
+    r = libxl_uuid_bytearray(&uuid);
     memset(nic_info, '\0', sizeof(*nic_info));
 
     nic_info->backend_domid = 0;
@@ -335,9 +333,9 @@ static void init_nic_info(libxl_device_n
     nic_info->mac[0] = 0x00;
     nic_info->mac[1] = 0x16;
     nic_info->mac[2] = 0x3e;
-    nic_info->mac[3] = 1 + (int) (0x7f * (rand() / (RAND_MAX + 1.0)));
-    nic_info->mac[4] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
-    nic_info->mac[5] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
+    nic_info->mac[3] = r[0] & 0x7f;
+    nic_info->mac[4] = r[1];
+    nic_info->mac[5] = r[2];
     nic_info->ifname = NULL;
     nic_info->bridge = strdup("xenbr0");
     CHK_ERRNO( asprintf(&nic_info->script, "%s/vif-bridge",
@@ -347,21 +345,26 @@ static void init_nic_info(libxl_device_n
 
 static void init_net2_info(libxl_device_net2 *net2_info, int devnum)
 {
+    const uint8_t *r;
+    libxl_uuid uuid;
+
+    libxl_uuid_generate(&uuid);
+    r = libxl_uuid_bytearray(&uuid);
     memset(net2_info, '\0', sizeof(*net2_info));
 
     net2_info->devid = devnum;
     net2_info->front_mac[0] = 0x00;
     net2_info->front_mac[1] = 0x16;
     net2_info->front_mac[2] = 0x3e;;
-    net2_info->front_mac[3] = 1 + (int) (0x7f * (rand() / (RAND_MAX + 1.0)));
-    net2_info->front_mac[4] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
-    net2_info->front_mac[5] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
+    net2_info->front_mac[3] = 0x7f & r[0];
+    net2_info->front_mac[4] = r[1];
+    net2_info->front_mac[5] = r[2];
     net2_info->back_mac[0] = 0x00;
     net2_info->back_mac[1] = 0x16;
     net2_info->back_mac[2] = 0x3e;
-    net2_info->back_mac[3] = 1 + (int) (0x7f * (rand() / (RAND_MAX + 1.0)));
-    net2_info->back_mac[4] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
-    net2_info->back_mac[5] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
+    net2_info->back_mac[3] = 0x7f & r[3];
+    net2_info->back_mac[4] = r[4];
+    net2_info->back_mac[5] = r[5];
     net2_info->back_trusted = 1;
     net2_info->filter_mac = 1;
     net2_info->max_bypasses = 5;
@@ -604,8 +607,16 @@ static void parse_config_data(const char
         c_info->name = strdup(buf);
     else
         c_info->name = "test";
-    random_uuid(&c_info->uuid);
-
+
+    if (!xlu_cfg_get_string (config, "uuid", &buf) ) {
+        if ( libxl_uuid_from_string(&c_info->uuid, buf) ) {
+            fprintf(stderr, "Failed to parse UUID: %s\n", buf);
+            exit(1);
+        }
+    }else{
+        libxl_uuid_generate(&c_info->uuid);
+    }
+ 
     if (!xlu_cfg_get_long(config, "oos", &l))
         c_info->oos = l;
 
@@ -1206,7 +1217,7 @@ static int preserve_domain(libxl_ctx *ct
         return 0;
     }
 
-    random_uuid(&new_uuid);
+    libxl_uuid_generate(&new_uuid);
 
     LOG("Preserving domain %d %s with suffix%s", domid, d_config->c_info.name, stime);
     rc = libxl_domain_preserve(ctx, domid, &d_config->c_info, stime, new_uuid);
diff -r 573ddf5cc145 tools/ocaml/libs/xl/xl_stubs.c
--- a/tools/ocaml/libs/xl/xl_stubs.c	Tue Aug 31 19:16:23 2010 +0100
+++ b/tools/ocaml/libs/xl/xl_stubs.c	Thu Sep 02 15:29:01 2010 +0100
@@ -131,6 +131,7 @@ static int domain_create_info_val (caml_
 {
 	CAMLparam1(v);
 	CAMLlocal1(a);
+	uint8_t *uuid = libxl_uuid_bytearray(&c_val->uuid);
 	int i;
 
 	c_val->hvm = Bool_val(Field(v, 0));
@@ -140,7 +141,7 @@ static int domain_create_info_val (caml_
 	c_val->name = dup_String_val(gc, Field(v, 4));
 	a = Field(v, 5);
 	for (i = 0; i < 16; i++)
-		c_val->uuid[i] = Int_val(Field(a, i));
+		uuid[i] = Int_val(Field(a, i));
 	string_string_tuple_array_val(gc, &(c_val->xsdata), Field(v, 6));
 	string_string_tuple_array_val(gc, &(c_val->platformdata), Field(v, 7));

^ permalink raw reply	[flat|nested] 6+ messages in thread