From: Sukadev Bhattiprolu <[email protected]> Date: Fri, 13 Mar 2009 17:25:42 -0700 Subject: [PATCH 5/6] Define and use proc_pid_checkpointable()
Create a proc file, /proc/pid/checkpointable, which shows '1' if task is checkpointable and '0' if it is not. To determine whether a task is checkpointable, the handler for this new proc file, shares the same code with sys_checkpoint(). Signed-off-by: Sukadev Bhattiprolu <[email protected]> --- checkpoint/checkpoint.c | 23 ++++++++++++++++------- fs/proc/base.c | 13 +++++++++++++ include/linux/checkpoint.h | 7 +++++++ 3 files changed, 36 insertions(+), 7 deletions(-) diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c index c16f30c..ad0956c 100644 --- a/checkpoint/checkpoint.c +++ b/checkpoint/checkpoint.c @@ -264,22 +264,31 @@ static int cr_write_all_tasks(struct cr_ctx *ctx) return ret; } +int task_checkpointable(struct task_struct *t) +{ + if (t->state == TASK_DEAD) { + pr_warning("c/r: task %d is TASK_DEAD\n", task_pid_vnr(t)); + return 0; + } + + /* Verify that task is frozen, unless it is self-checkpoint */ + if (t != current && !frozen(t)) + return 0; + + return 1; +} + static int cr_may_checkpoint_task(struct task_struct *t, struct cr_ctx *ctx) { pr_debug("check %d\n", task_pid_nr_ns(t, ctx->root_nsproxy->pid_ns)); - if (t->state == TASK_DEAD) { - pr_warning("c/r: task %d is TASK_DEAD\n", task_pid_vnr(t)); + /* verify that the task is checkpointable */ + if (!task_checkpointable(t)) return -EAGAIN; - } if (!ptrace_may_access(t, PTRACE_MODE_READ)) return -EPERM; - /* verify that the task is frozen (unless self) */ - if (t != current && !frozen(t)) - return -EBUSY; - /* FIXME: change this for nested containers */ if (task_nsproxy(t) != ctx->root_nsproxy) return -EPERM; diff --git a/fs/proc/base.c b/fs/proc/base.c index bde92c3..989ca93 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2501,6 +2501,13 @@ static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns, return 0; } +#ifdef CONFIG_CHECKPOINT_RESTART +static int proc_pid_checkpointable(struct task_struct *task, char *buffer) +{ + return sprintf(buffer, "%d\n", task_checkpointable(task)); +} +#endif + /* * Thread groups */ @@ -2580,6 +2587,9 @@ static const struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_TASK_IO_ACCOUNTING INF("io", S_IRUGO, proc_tgid_io_accounting), #endif +#ifdef CONFIG_CHECKPOINT_RESTART + INF("checkpointable", S_IRUGO, proc_pid_checkpointable), +#endif }; static int proc_tgid_base_readdir(struct file * filp, @@ -2915,6 +2925,9 @@ static const struct pid_entry tid_base_stuff[] = { #ifdef CONFIG_TASK_IO_ACCOUNTING INF("io", S_IRUGO, proc_tid_io_accounting), #endif +#ifdef CONFIG_CHECKPOINT_RESTART + INF("checkpointable", S_IRUGO, proc_pid_checkpointable), +#endif }; static int proc_tid_base_readdir(struct file * filp, diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h index 484be56..d1f53a6 100644 --- a/include/linux/checkpoint.h +++ b/include/linux/checkpoint.h @@ -142,6 +142,8 @@ static inline int cr_enabled(void) return 1; } +int task_checkpointable(struct task_struct *t); + #else /* !CONFIG_CHECKPOINT_RESTART */ static inline void files_deny_checkpointing(struct files_struct *files) {} @@ -162,5 +164,10 @@ static inline int cr_enabled(void) return 0; } +static inline int task_checkpointable(struct task_struct *t) +{ + return 0; +} + #endif /* CONFIG_CHECKPOINT_RESTART */ #endif /* _CHECKPOINT_CKPT_H_ */ -- 1.5.2.5 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
