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: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index c59852b..f4b1e14 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -121,6 +121,10 @@
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 @@
.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);
