Re: [RFC v13][PATCH 01/14] Create syscalls: sys_checkpoint, sys_restart

From: Randy Dunlap
Date: Tue Jan 27 2009 - 12:22:18 EST


Oren Laadan wrote:
> Changelog[v5]:
> - Config is 'def_bool n' by default

That's true by default; it doesn't have to be written/typed.


> Signed-off-by: Oren Laadan <orenl@xxxxxxxxxxxxxxx>
> Acked-by: Serge Hallyn <serue@xxxxxxxxxx>
> Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/unistd_32.h | 2 +
> arch/x86/kernel/syscall_table_32.S | 2 +
> checkpoint/Kconfig | 11 +++++++++
> checkpoint/Makefile | 5 ++++
> checkpoint/sys.c | 41 ++++++++++++++++++++++++++++++++++++
> include/linux/syscalls.h | 2 +
> init/Kconfig | 2 +
> kernel/sys_ni.c | 4 +++
> 8 files changed, 69 insertions(+), 0 deletions(-)
> create mode 100644 checkpoint/Kconfig
> create mode 100644 checkpoint/Makefile
> create mode 100644 checkpoint/sys.c
>
> diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
> index f2bba78..a5f9e09 100644
> --- a/arch/x86/include/asm/unistd_32.h
> +++ b/arch/x86/include/asm/unistd_32.h
> @@ -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 --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
> index d44395f..5543136 100644
> --- a/arch/x86/kernel/syscall_table_32.S
> +++ b/arch/x86/kernel/syscall_table_32.S
> @@ -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 --git a/checkpoint/sys.c b/checkpoint/sys.c
> new file mode 100644
> index 0000000..375129c
> --- /dev/null
> +++ b/checkpoint/sys.c
> @@ -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/syscalls.h>

and then use the new syscall definition macros.
See SYSCALL_DEFINE* in kernel/*.c (current git tree) for examples.

> +#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 --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 04fb47b..9750393 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -621,6 +621,8 @@ asmlinkage long sys_timerfd_gettime(int ufd, struct itimerspec __user *otmr);
> 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 --git a/init/Kconfig b/init/Kconfig
> index f763762..57364fe 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -814,6 +814,8 @@ config MARKERS
>
> source "arch/Kconfig"
>
> +source "checkpoint/Kconfig"
> +
> endmenu # General setup
>
> config HAVE_GENERIC_DMA_COHERENT
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index e14a232..fcd65cc 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -174,3 +174,7 @@ 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);


--
~Randy
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