From: Daniel Lezcano <daniel.lezcano@free.fr>
Date: Tue, 7 Jul 2009 20:51:18 +0000 (+0200)
Subject: use glibc clone instead of clone syscall
X-Git-Tag: lxc_0_6_3~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5bb3ba8acd29d11c92845b06a1f0852b642f02c7;p=thirdparty%2Flxc.git

use glibc clone instead of clone syscall

This patch replaces the clone syscall by the glibc clone making
the code not tied with the syscalls number declaration.

The unshare syscall has been removed as it is not interesting.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
---

diff --git a/src/lxc/Makefile.am b/src/lxc/Makefile.am
index f40b31f55..90e522aac 100644
--- a/src/lxc/Makefile.am
+++ b/src/lxc/Makefile.am
@@ -35,7 +35,7 @@ liblxc_la_SOURCES = \
 	lxc.h \
 	utils.c utils.h \
 	lock.c lock.h \
-	namespace.h \
+	namespace.h namespace.c \
 	conf.c conf.h \
 	list.h \
 	state.c state.h \
diff --git a/src/lxc/namespace.c b/src/lxc/namespace.c
new file mode 100644
index 000000000..72b0fc9f3
--- /dev/null
+++ b/src/lxc/namespace.c
@@ -0,0 +1,61 @@
+/*
+ * lxc: linux Container library
+ *
+ * (C) Copyright IBM Corp. 2007, 2009
+ *
+ * Authors:
+ * Daniel Lezcano <dlezcano at fr.ibm.com>
+ *
+ * This library 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; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <unistd.h>
+#include <alloca.h>
+#include <errno.h>
+#include <signal.h>
+#include <namespace.h>
+
+#include <lxc/lxc.h>
+
+lxc_log_define(lxc_namespace, lxc);
+
+struct clone_arg {
+	int (*fn)(void *);
+	void *arg;
+};
+
+static int do_clone(void *arg)
+{
+	struct clone_arg *clone_arg = arg;
+	return clone_arg->fn(clone_arg->arg);
+}
+
+pid_t lxc_clone(int (*fn)(void *), void *arg, int flags)
+{
+	struct clone_arg clone_arg = {
+		.fn = fn,
+		.arg = arg,
+	};
+
+	long stack_size = sysconf(_SC_PAGESIZE);
+	void *stack = alloca(stack_size) + stack_size;
+	pid_t ret;
+
+	ret = clone(do_clone, stack, flags | SIGCHLD, &clone_arg);
+	if (ret < 0)
+		ERROR("failed to clone(0x%x): %s", flags, strerror(errno));
+
+	return ret;
+}
diff --git a/src/lxc/namespace.h b/src/lxc/namespace.h
index ec51cb4b9..884b22293 100644
--- a/src/lxc/namespace.h
+++ b/src/lxc/namespace.h
@@ -1,7 +1,7 @@
 /*
  * lxc: linux Container library
  *
- * (C) Copyright IBM Corp. 2007, 2008
+ * (C) Copyright IBM Corp. 2007, 2009
  *
  * Authors:
  * Daniel Lezcano <dlezcano at fr.ibm.com>
@@ -24,6 +24,9 @@
 #define __namespace_h
 
 #include <syscall.h>
+#define _GNU_SOURCE
+#include <sched.h>
+
 #ifndef CLONE_FS
 #  define CLONE_FS                0x00000200
 #endif
@@ -45,21 +48,7 @@
 #ifndef CLONE_NEWNET
 #  define CLONE_NEWNET            0x40000000
 #endif
-#ifndef __NR_unshare
-#  ifdef __i386__
-#    define __NR_unshare 310
-#  elif __x86_64__
-#    define __NR_unshare 272
-#  elif __ia64__
-#    define __NR_unshare 1296
-#  elif __s390__
-#    define __NR_unshare 303
-#  elif __powerpc__
-#    define __NR_unshare 282
-#else
-#    error "unsupported architecture"
-#  endif
-#endif
+
 #if __i386__ || __x86_64__ || __powerpc__
 #   define fork_ns(flags) syscall(SYS_clone, flags|SIGCHLD, NULL)
 #elif __s390__
@@ -69,5 +58,9 @@
 #else
 #   error "unsupported architecture"
 #endif
-#define unshare_ns(flags) syscall(__NR_unshare, flags, NULL)
+
+#define unshare_ns(flags) unshare(flags)
+
+extern pid_t lxc_clone(int (*fn)(void *), void *arg, int flags);
+
 #endif