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Commit be614086 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
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proc: implement proc_single_file_operations 



Currently many /proc/pid files use a crufty precursor to the current seq_file
api, and they don't have direct access to the pid_namespace or the pid of for
which they are displaying data.

So implement proc_single_file_operations to make the seq_file routines easy to
use, and to give access to the full state of the pid of we are displaying data
for.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 94413d88

fs/proc/base.c

+43 −0
Original line number Diff line number Diff line
@@ -121,6 +121,10 @@ struct pid_entry { 
	NOD(NAME, (S_IFREG|(MODE)), 			\

		NULL, &proc_info_file_operations,	\

		{ .proc_read = &proc_##OTYPE } )

#define ONE(NAME, MODE, OTYPE)				\

	NOD(NAME, (S_IFREG|(MODE)), 			\

		NULL, &proc_single_file_operations,	\

		{ .proc_show = &proc_##OTYPE } )



int maps_protect;

EXPORT_SYMBOL(maps_protect);
@@ -658,6 +662,45 @@ static const struct file_operations proc_info_file_operations = { 
	.read		= proc_info_read,

};



static int proc_single_show(struct seq_file *m, void *v)

{

	struct inode *inode = m->private;

	struct pid_namespace *ns;

	struct pid *pid;

	struct task_struct *task;

	int ret;



	ns = inode->i_sb->s_fs_info;

	pid = proc_pid(inode);

	task = get_pid_task(pid, PIDTYPE_PID);

	if (!task)

		return -ESRCH;



	ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);



	put_task_struct(task);

	return ret;

}



static int proc_single_open(struct inode *inode, struct file *filp)

{

	int ret;

	ret = single_open(filp, proc_single_show, NULL);

	if (!ret) {

		struct seq_file *m = filp->private_data;



		m->private = inode;

	}

	return ret;

}



static const struct file_operations proc_single_file_operations = {

	.open		= proc_single_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};



static int mem_open(struct inode* inode, struct file* file)

{

	file->private_data = (void*)((long)current->self_exec_id);

include/linux/proc_fs.h

+3 −0
Original line number Diff line number Diff line
@@ -262,6 +262,9 @@ extern void kclist_add(struct kcore_list *, void *, size_t); 
union proc_op {

	int (*proc_get_link)(struct inode *, struct dentry **, struct vfsmount **);

	int (*proc_read)(struct task_struct *task, char *page);

	int (*proc_show)(struct seq_file *m,

		struct pid_namespace *ns, struct pid *pid,

		struct task_struct *task);

};



struct proc_inode {