[PATCH v2 10/18] tools/misc: introduce helper to initialise Dom0

[Wei Liu <wei.liu2@citrix.com>]

This small helper is responsible for generating Dom0 JSON config stub
and writing Dom0 xenstore entries. This helpers subsumes two calls to
xenstore-write in xencommons script.

Dom0 UUID is intentionally left untouched, so it is always all zeros.
This makes sure that we don't leak Dom0 stubs across rebooting.

Modify tools/Makefile to move "misc" after "libxl" as it now depends on
libxl to build.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 .gitignore                            |    1 +
 tools/Makefile                        |    2 +-
 tools/hotplug/Linux/init.d/xencommons |    5 +-
 tools/misc/Makefile                   |    8 +-
 tools/misc/xen-init-dom0.c            |  130 +++++++++++++++++++++++++++++++++
 5 files changed, 140 insertions(+), 6 deletions(-)
 create mode 100644 tools/misc/xen-init-dom0.c

diff --git a/.gitignore b/.gitignore
index fefe13c..a6370d8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -183,6 +183,7 @@ tools/misc/gtracestat
 tools/misc/xenlockprof
 tools/misc/lowmemd
 tools/misc/xencov
+tools/misc/xen-init-dom0
 tools/pygrub/build/*
 tools/python/build/*
 tools/python/xen/util/path.py
diff --git a/tools/Makefile b/tools/Makefile
index b6476c9..89fc698 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -6,7 +6,6 @@ SUBDIRS-y += include
 SUBDIRS-y += libxc
 SUBDIRS-$(FLASK_ENABLE) += flask
 SUBDIRS-y += xenstore
-SUBDIRS-y += misc
 SUBDIRS-y += examples
 SUBDIRS-y += hotplug
 SUBDIRS-y += xentrace
@@ -30,6 +29,7 @@ endif
 
 SUBDIRS-y += xenpmd
 SUBDIRS-y += libxl
+SUBDIRS-y += misc
 SUBDIRS-$(CONFIG_X86) += xenpaging
 SUBDIRS-$(CONFIG_X86) += debugger/gdbsx
 SUBDIRS-$(CONFIG_X86) += debugger/kdd
diff --git a/tools/hotplug/Linux/init.d/xencommons b/tools/hotplug/Linux/init.d/xencommons
index 4ebd636..1811eee 100644
--- a/tools/hotplug/Linux/init.d/xencommons
+++ b/tools/hotplug/Linux/init.d/xencommons
@@ -108,9 +108,8 @@ do_start () {
 		    exit 1
 		fi
 
-		echo Setting domain 0 name and domid...
-		${BINDIR}/xenstore-write "/local/domain/0/name" "Domain-0"
-		${BINDIR}/xenstore-write "/local/domain/0/domid" 0
+		echo Setting domain 0 name, domid and JSON config...
+		${PRIVATE_BINDIR}/xen-init-dom0
 	fi
 
 	echo Starting xenconsoled...
diff --git a/tools/misc/Makefile b/tools/misc/Makefile
index 69b1817..1223e19 100644
--- a/tools/misc/Makefile
+++ b/tools/misc/Makefile
@@ -6,10 +6,11 @@ CFLAGS += -Werror
 CFLAGS += $(CFLAGS_libxenctrl)
 CFLAGS += $(CFLAGS_xeninclude)
 CFLAGS += $(CFLAGS_libxenstore)
+CFLAGS += $(CFLAGS_libxenlight)
 
 HDRS     = $(wildcard *.h)
 
-TARGETS-y := xenperf xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd xencov
+TARGETS-y := xenperf xenpm xen-tmem-list-parse gtraceview gtracestat xenlockprof xenwatchdogd xencov xen-init-dom0
 TARGETS-$(CONFIG_X86) += xen-detect xen-hvmctx xen-hvmcrash xen-lowmemd xen-mfndump
 TARGETS-$(CONFIG_MIGRATE) += xen-hptool
 TARGETS := $(TARGETS-y)
@@ -26,7 +27,7 @@ INSTALL_SBIN-$(CONFIG_X86) += xen-hvmctx xen-hvmcrash xen-lowmemd xen-mfndump
 INSTALL_SBIN-$(CONFIG_MIGRATE) += xen-hptool
 INSTALL_SBIN := $(INSTALL_SBIN-y)
 
-INSTALL_PRIVBIN-y := xenpvnetboot
+INSTALL_PRIVBIN-y := xenpvnetboot xen-init-dom0
 INSTALL_PRIVBIN := $(INSTALL_PRIVBIN-y)
 
 # Include configure output (config.h) to headers search path
@@ -90,4 +91,7 @@ gtraceview: gtraceview.o
 xencov: xencov.o
 	$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
 
+xen-init-dom0: xen-init-dom0.o
+	$(CC) $(LDFLAGS) $^ -o $@ $(LDLIBS_libxenctrl) $(LDLIBS_libxenstore) $(LDLIBS_libxenlight) $(APPEND_LDFLAGS)
+
 -include $(DEPS)
diff --git a/tools/misc/xen-init-dom0.c b/tools/misc/xen-init-dom0.c
new file mode 100644
index 0000000..4bb1a96
--- /dev/null
+++ b/tools/misc/xen-init-dom0.c
@@ -0,0 +1,130 @@
+#include <err.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <xenctrl.h>
+#include <xenstore.h>
+#include <libxl.h>
+
+#define DOMNAME_PATH   "/local/domain/0/name"
+#define DOMID_PATH     "/local/domain/0/domid"
+
+static libxl_ctx *ctx;
+static xentoollog_logger_stdiostream *logger;
+static xc_interface *xch;
+static struct xs_handle *xsh;
+
+static void ctx_alloc(void)
+{
+    if (libxl_ctx_alloc(&ctx, LIBXL_VERSION, 0,
+                        (xentoollog_logger *)logger)) {
+        fprintf(stderr, "cannot init libxl context\n");
+        exit(1);
+    }
+    xch = xc_interface_open(0, 0, 0);
+    if (!xch) {
+        fprintf(stderr, "cannot open libxc handle\n");
+        exit(1);
+    }
+    xsh = xs_open(0);
+    if (!xsh) {
+        fprintf(stderr, "cannot open xenstore connection\n");
+        exit(1);
+    }
+}
+
+static void ctx_free(void)
+{
+    if (ctx) {
+        libxl_ctx_free(ctx);
+        ctx = NULL;
+    }
+    if (logger) {
+        xtl_logger_destroy((xentoollog_logger *)logger);
+        logger = NULL;
+    }
+    if (xch) {
+        xc_interface_close(xch);
+        xch = NULL;
+    }
+    if (xsh) {
+        xs_close(xsh);
+        xsh = NULL;
+    }
+}
+
+int main(int argc, char **argv)
+{
+    int rc;
+    libxl_domain_config dom0_config;
+    char *domname_string = NULL, *domid_string = NULL;
+    char *json = NULL;;
+
+    logger = xtl_createlogger_stdiostream(stderr, XTL_ERROR, 0);
+    if (!logger) exit(1);
+
+    atexit(ctx_free);
+
+    ctx_alloc();
+
+    libxl_domain_config_init(&dom0_config);
+
+    /* Sanity check: this program can only be run once. */
+    domid_string = xs_read(xsh, XBT_NULL, DOMID_PATH, NULL);
+    domname_string = xs_read(xsh, XBT_NULL, DOMNAME_PATH, NULL);
+    if (domid_string && domname_string) {
+        fprintf(stderr, "Dom0 is already set up\n");
+        rc = 0;
+        goto out;
+    }
+
+    /* Generate stub JSON config. */
+    dom0_config.c_info.type = LIBXL_DOMAIN_TYPE_PV;
+    libxl_domain_build_info_init_type(&dom0_config.b_info,
+                                      LIBXL_DOMAIN_TYPE_PV);
+
+    json = libxl_domain_config_to_json(ctx, &dom0_config);
+    /* libxl-json format requires the string ends with '\0'. Code
+     * snippet taken from libxl.
+     */
+    rc = libxl_userdata_store(ctx, 0, "libxl-json",
+                              (const uint8_t *)json,
+                              strlen(json) + 1 /* inlcude '\0' */);
+    if (rc) {
+        fprintf(stderr, "cannot store stub json config for Dom0\n");
+        goto out;
+    }
+
+    /* Write xenstore entries. */
+    if (!xs_write(xsh, XBT_NULL, DOMID_PATH, "0", strlen("0"))) {
+        fprintf(stderr, "cannot set domid for Dom0\n");
+        rc = 1;
+        goto out;
+    }
+
+    if (!xs_write(xsh, XBT_NULL, DOMNAME_PATH, "Domain-0",
+                  strlen("Domain-0"))) {
+        fprintf(stderr, "cannot set domain name for Dom0\n");
+        rc = 1;
+        goto out;
+    }
+
+    printf("Done setting up Dom0\n");
+
+out:
+    libxl_domain_config_dispose(&dom0_config);
+    free(domid_string);
+    free(domname_string);
+    free(json);
+    return rc;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
1.7.10.4