Re: [PATCH 1/9] Create syscalls: sys_checkpoint, sys_restart

From: Oren Laadan <redacted>

Create trivial sys_checkpoint and sys_restore system calls. They will
enable to checkpoint and restart an entire container, to and from a
checkpoint image file descriptor.

The syscalls take a file descriptor (for the image file) and flags as
arguments. For sys_checkpoint the first argument identifies the target
container; for sys_restart it will identify the checkpoint image.

Signed-off-by: Oren Laadan <redacted>
Acked-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Dave Hansen <redacted>
---

 linux-2.6.git-dave/arch/x86/kernel/syscall_table_32.S |    2
 linux-2.6.git-dave/checkpoint/Kconfig                 |   11 ++++
 linux-2.6.git-dave/checkpoint/Makefile                |    5 ++
 linux-2.6.git-dave/checkpoint/sys.c                   |   41 ++++++++++++++++++
 linux-2.6.git-dave/include/asm-x86/unistd_32.h        |    2
 linux-2.6.git-dave/include/linux/syscalls.h           |    2
 linux-2.6.git-dave/init/Kconfig                       |    2
 linux-2.6.git-dave/kernel/sys_ni.c                    |    4 +
 8 files changed, 69 insertions(+)

diff -puN arch/x86/kernel/syscall_table_32.S~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart arch/x86/kernel/syscall_table_32.S

--- linux-2.6.git/arch/x86/kernel/syscall_table_32.S~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart   2008-10-16 10:53:33.000000000 -0700
+++ linux-2.6.git-dave/arch/x86/kernel/syscall_table_32.S       2008-10-16 10:53:33.000000000 -0700

@@ -332,3 +332,5 @@ ENTRY(sys_call_table)
       .long sys_dup3                  /* 330 */
       .long sys_pipe2
       .long sys_inotify_init1
+       .long sys_checkpoint
+       .long sys_restart

diff -puN /dev/null checkpoint/Kconfig

--- /dev/null   2008-09-02 09:40:19.000000000 -0700
+++ linux-2.6.git-dave/checkpoint/Kconfig       2008-10-16 10:53:33.000000000 -0700

@@ -0,0 +1,11 @@
+config CHECKPOINT_RESTART
+       prompt "Enable checkpoint/restart (EXPERIMENTAL)"
+       def_bool n
+       depends on X86_32 && EXPERIMENTAL
+       help
+         Application checkpoint/restart is the ability to save the
+         state of a running application so that it can later resume
+         its execution from the time at which it was checkpointed.
+
+         Turning this option on will enable checkpoint and restart
+         functionality in the kernel.

diff -puN /dev/null checkpoint/Makefile

--- /dev/null   2008-09-02 09:40:19.000000000 -0700
+++ linux-2.6.git-dave/checkpoint/Makefile      2008-10-16 10:53:33.000000000 -0700

@@ -0,0 +1,5 @@
+#
+# Makefile for linux checkpoint/restart.
+#
+
+obj-$(CONFIG_CHECKPOINT_RESTART) += sys.o

diff -puN /dev/null checkpoint/sys.c

--- /dev/null   2008-09-02 09:40:19.000000000 -0700
+++ linux-2.6.git-dave/checkpoint/sys.c 2008-10-16 10:53:33.000000000 -0700

@@ -0,0 +1,41 @@
+/*
+ *  Generic container checkpoint-restart
+ *
+ *  Copyright (C) 2008 Oren Laadan
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License.  See the file COPYING in the main directory of the Linux
+ *  distribution for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+
+/**
+ * sys_checkpoint - checkpoint a container
+ * @pid: pid of the container init(1) process
+ * @fd: file to which dump the checkpoint image
+ * @flags: checkpoint operation flags
+ *
+ * Returns positive identifier on success, 0 when returning from restart
+ * or negative value on error
+ */
+asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags)
+{
+       pr_debug("sys_checkpoint not implemented yet\n");
+       return -ENOSYS;
+}
+/**
+ * sys_restart - restart a container
+ * @crid: checkpoint image identifier
+ * @fd: file from which read the checkpoint image
+ * @flags: restart operation flags
+ *
+ * Returns negative value on error, or otherwise returns in the realm
+ * of the original checkpoint
+ */
+asmlinkage long sys_restart(int crid, int fd, unsigned long flags)
+{
+       pr_debug("sys_restart not implemented yet\n");
+       return -ENOSYS;
+}

diff -puN include/asm-x86/unistd_32.h~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart include/asm-x86/unistd_32.h

--- linux-2.6.git/include/asm-x86/unistd_32.h~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart  2008-10-16 10:53:33.000000000 -0700
+++ linux-2.6.git-dave/include/asm-x86/unistd_32.h      2008-10-16 10:53:33.000000000 -0700

@@ -338,6 +338,8 @@
 #define __NR_dup3              330
 #define __NR_pipe2             331
 #define __NR_inotify_init1     332
+#define __NR_checkpoint                333
+#define __NR_restart           334

 #ifdef __KERNEL__

diff -puN include/linux/syscalls.h~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart include/linux/syscalls.h

--- linux-2.6.git/include/linux/syscalls.h~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart     2008-10-16 10:53:33.000000000 -0700
+++ linux-2.6.git-dave/include/linux/syscalls.h 2008-10-16 10:53:33.000000000 -0700

@@ -622,6 +622,8 @@ asmlinkage long sys_timerfd_gettime(int
 asmlinkage long sys_eventfd(unsigned int count);
 asmlinkage long sys_eventfd2(unsigned int count, int flags);
 asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len);
+asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags);
+asmlinkage long sys_restart(int crid, int fd, unsigned long flags);

 int kernel_execve(const char *filename, char *const argv[], char *const envp[]);

diff -puN init/Kconfig~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart init/Kconfig

--- linux-2.6.git/init/Kconfig~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart 2008-10-16 10:53:33.000000000 -0700
+++ linux-2.6.git-dave/init/Kconfig     2008-10-16 10:53:33.000000000 -0700

@@ -779,6 +779,8 @@ config MARKERS

 source "arch/Kconfig"

+source "checkpoint/Kconfig"
+
 endmenu                # General setup

 config HAVE_GENERIC_DMA_COHERENT

diff -puN kernel/sys_ni.c~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart kernel/sys_ni.c

--- linux-2.6.git/kernel/sys_ni.c~v6_PATCH_1_9_Create_syscalls-_sys_checkpoint_sys_restart      2008-10-16 10:53:33.000000000 -0700
+++ linux-2.6.git-dave/kernel/sys_ni.c  2008-10-16 10:53:33.000000000 -0700

@@ -169,3 +169,7 @@ cond_syscall(compat_sys_timerfd_settime)
 cond_syscall(compat_sys_timerfd_gettime);
 cond_syscall(sys_eventfd);
 cond_syscall(sys_eventfd2);
+
+/* checkpoint/restart */
+cond_syscall(sys_checkpoint);
+cond_syscall(sys_restart);

_
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