mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-24 12:44:11 +08:00
e656d8a6f7
I had visions at one point of splitting proc into two filesystems. If that had happened proc/self being the the part of proc that actually deals with pids would have been a nice cleanup. As it is proc/self requires a lot of unnecessary infrastructure for a single file. The only user visible change is that a mounted /proc for a pid namespace that is dead now shows a broken proc symlink, instead of being completely invisible. I don't think anyone will notice or care. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
#include <linux/proc_fs.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/namei.h>
|
|
|
|
/*
|
|
* /proc/self:
|
|
*/
|
|
static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
|
|
int buflen)
|
|
{
|
|
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
|
|
pid_t tgid = task_tgid_nr_ns(current, ns);
|
|
char tmp[PROC_NUMBUF];
|
|
if (!tgid)
|
|
return -ENOENT;
|
|
sprintf(tmp, "%d", tgid);
|
|
return vfs_readlink(dentry,buffer,buflen,tmp);
|
|
}
|
|
|
|
static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
|
|
{
|
|
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
|
|
pid_t tgid = task_tgid_nr_ns(current, ns);
|
|
char *name = ERR_PTR(-ENOENT);
|
|
if (tgid) {
|
|
/* 11 for max length of signed int in decimal + NULL term */
|
|
name = kmalloc(12, GFP_KERNEL);
|
|
if (!name)
|
|
name = ERR_PTR(-ENOMEM);
|
|
else
|
|
sprintf(name, "%d", tgid);
|
|
}
|
|
nd_set_link(nd, name);
|
|
return NULL;
|
|
}
|
|
|
|
static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
|
|
void *cookie)
|
|
{
|
|
char *s = nd_get_link(nd);
|
|
if (!IS_ERR(s))
|
|
kfree(s);
|
|
}
|
|
|
|
static const struct inode_operations proc_self_inode_operations = {
|
|
.readlink = proc_self_readlink,
|
|
.follow_link = proc_self_follow_link,
|
|
.put_link = proc_self_put_link,
|
|
};
|
|
|
|
void __init proc_self_init(void)
|
|
{
|
|
struct proc_dir_entry *proc_self_symlink;
|
|
mode_t mode;
|
|
|
|
mode = S_IFLNK | S_IRWXUGO;
|
|
proc_self_symlink = proc_create("self", mode, NULL, NULL );
|
|
proc_self_symlink->proc_iops = &proc_self_inode_operations;
|
|
}
|