302 строки
7.0 KiB
C
302 строки
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* linux/fs/proc/root.c
|
|
*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
*
|
|
* proc root directory handling functions
|
|
*/
|
|
|
|
#include <linux/uaccess.h>
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/time.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/init.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sched/stat.h>
|
|
#include <linux/module.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/user_namespace.h>
|
|
#include <linux/fs_context.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/pid_namespace.h>
|
|
#include <linux/fs_parser.h>
|
|
#include <linux/cred.h>
|
|
#include <linux/magic.h>
|
|
#include <linux/slab.h>
|
|
|
|
#include "internal.h"
|
|
|
|
struct proc_fs_context {
|
|
struct pid_namespace *pid_ns;
|
|
unsigned int mask;
|
|
int hidepid;
|
|
int gid;
|
|
};
|
|
|
|
enum proc_param {
|
|
Opt_gid,
|
|
Opt_hidepid,
|
|
};
|
|
|
|
static const struct fs_parameter_spec proc_fs_parameters[] = {
|
|
fsparam_u32("gid", Opt_gid),
|
|
fsparam_u32("hidepid", Opt_hidepid),
|
|
{}
|
|
};
|
|
|
|
static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
|
|
{
|
|
struct proc_fs_context *ctx = fc->fs_private;
|
|
struct fs_parse_result result;
|
|
int opt;
|
|
|
|
opt = fs_parse(fc, proc_fs_parameters, param, &result);
|
|
if (opt < 0)
|
|
return opt;
|
|
|
|
switch (opt) {
|
|
case Opt_gid:
|
|
ctx->gid = result.uint_32;
|
|
break;
|
|
|
|
case Opt_hidepid:
|
|
ctx->hidepid = result.uint_32;
|
|
if (ctx->hidepid < HIDEPID_OFF ||
|
|
ctx->hidepid > HIDEPID_INVISIBLE)
|
|
return invalfc(fc, "hidepid value must be between 0 and 2.\n");
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
ctx->mask |= 1 << opt;
|
|
return 0;
|
|
}
|
|
|
|
static void proc_apply_options(struct super_block *s,
|
|
struct fs_context *fc,
|
|
struct pid_namespace *pid_ns,
|
|
struct user_namespace *user_ns)
|
|
{
|
|
struct proc_fs_context *ctx = fc->fs_private;
|
|
|
|
if (ctx->mask & (1 << Opt_gid))
|
|
pid_ns->pid_gid = make_kgid(user_ns, ctx->gid);
|
|
if (ctx->mask & (1 << Opt_hidepid))
|
|
pid_ns->hide_pid = ctx->hidepid;
|
|
}
|
|
|
|
static int proc_fill_super(struct super_block *s, struct fs_context *fc)
|
|
{
|
|
struct pid_namespace *pid_ns = get_pid_ns(s->s_fs_info);
|
|
struct inode *root_inode;
|
|
int ret;
|
|
|
|
proc_apply_options(s, fc, pid_ns, current_user_ns());
|
|
|
|
/* User space would break if executables or devices appear on proc */
|
|
s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
|
|
s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
|
|
s->s_blocksize = 1024;
|
|
s->s_blocksize_bits = 10;
|
|
s->s_magic = PROC_SUPER_MAGIC;
|
|
s->s_op = &proc_sops;
|
|
s->s_time_gran = 1;
|
|
|
|
/*
|
|
* procfs isn't actually a stacking filesystem; however, there is
|
|
* too much magic going on inside it to permit stacking things on
|
|
* top of it
|
|
*/
|
|
s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
|
|
|
|
/* procfs dentries and inodes don't require IO to create */
|
|
s->s_shrink.seeks = 0;
|
|
|
|
pde_get(&proc_root);
|
|
root_inode = proc_get_inode(s, &proc_root);
|
|
if (!root_inode) {
|
|
pr_err("proc_fill_super: get root inode failed\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
s->s_root = d_make_root(root_inode);
|
|
if (!s->s_root) {
|
|
pr_err("proc_fill_super: allocate dentry failed\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ret = proc_setup_self(s);
|
|
if (ret) {
|
|
return ret;
|
|
}
|
|
return proc_setup_thread_self(s);
|
|
}
|
|
|
|
static int proc_reconfigure(struct fs_context *fc)
|
|
{
|
|
struct super_block *sb = fc->root->d_sb;
|
|
struct pid_namespace *pid = sb->s_fs_info;
|
|
|
|
sync_filesystem(sb);
|
|
|
|
proc_apply_options(sb, fc, pid, current_user_ns());
|
|
return 0;
|
|
}
|
|
|
|
static int proc_get_tree(struct fs_context *fc)
|
|
{
|
|
struct proc_fs_context *ctx = fc->fs_private;
|
|
|
|
return get_tree_keyed(fc, proc_fill_super, ctx->pid_ns);
|
|
}
|
|
|
|
static void proc_fs_context_free(struct fs_context *fc)
|
|
{
|
|
struct proc_fs_context *ctx = fc->fs_private;
|
|
|
|
put_pid_ns(ctx->pid_ns);
|
|
kfree(ctx);
|
|
}
|
|
|
|
static const struct fs_context_operations proc_fs_context_ops = {
|
|
.free = proc_fs_context_free,
|
|
.parse_param = proc_parse_param,
|
|
.get_tree = proc_get_tree,
|
|
.reconfigure = proc_reconfigure,
|
|
};
|
|
|
|
static int proc_init_fs_context(struct fs_context *fc)
|
|
{
|
|
struct proc_fs_context *ctx;
|
|
|
|
ctx = kzalloc(sizeof(struct proc_fs_context), GFP_KERNEL);
|
|
if (!ctx)
|
|
return -ENOMEM;
|
|
|
|
ctx->pid_ns = get_pid_ns(task_active_pid_ns(current));
|
|
put_user_ns(fc->user_ns);
|
|
fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
|
|
fc->fs_private = ctx;
|
|
fc->ops = &proc_fs_context_ops;
|
|
return 0;
|
|
}
|
|
|
|
static void proc_kill_sb(struct super_block *sb)
|
|
{
|
|
struct pid_namespace *ns;
|
|
|
|
ns = (struct pid_namespace *)sb->s_fs_info;
|
|
if (ns->proc_self)
|
|
dput(ns->proc_self);
|
|
if (ns->proc_thread_self)
|
|
dput(ns->proc_thread_self);
|
|
kill_anon_super(sb);
|
|
|
|
/* Make the pid namespace safe for the next mount of proc */
|
|
ns->proc_self = NULL;
|
|
ns->proc_thread_self = NULL;
|
|
ns->pid_gid = GLOBAL_ROOT_GID;
|
|
ns->hide_pid = 0;
|
|
|
|
put_pid_ns(ns);
|
|
}
|
|
|
|
static struct file_system_type proc_fs_type = {
|
|
.name = "proc",
|
|
.init_fs_context = proc_init_fs_context,
|
|
.parameters = proc_fs_parameters,
|
|
.kill_sb = proc_kill_sb,
|
|
.fs_flags = FS_USERNS_MOUNT | FS_DISALLOW_NOTIFY_PERM,
|
|
};
|
|
|
|
void __init proc_root_init(void)
|
|
{
|
|
proc_init_kmemcache();
|
|
set_proc_pid_nlink();
|
|
proc_self_init();
|
|
proc_thread_self_init();
|
|
proc_symlink("mounts", NULL, "self/mounts");
|
|
|
|
proc_net_init();
|
|
proc_mkdir("fs", NULL);
|
|
proc_mkdir("driver", NULL);
|
|
proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
|
|
#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
|
|
/* just give it a mountpoint */
|
|
proc_create_mount_point("openprom");
|
|
#endif
|
|
proc_tty_init();
|
|
proc_mkdir("bus", NULL);
|
|
proc_sys_init();
|
|
|
|
register_filesystem(&proc_fs_type);
|
|
}
|
|
|
|
static int proc_root_getattr(const struct path *path, struct kstat *stat,
|
|
u32 request_mask, unsigned int query_flags)
|
|
{
|
|
generic_fillattr(d_inode(path->dentry), stat);
|
|
stat->nlink = proc_root.nlink + nr_processes();
|
|
return 0;
|
|
}
|
|
|
|
static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
|
|
{
|
|
if (!proc_pid_lookup(dentry, flags))
|
|
return NULL;
|
|
|
|
return proc_lookup(dir, dentry, flags);
|
|
}
|
|
|
|
static int proc_root_readdir(struct file *file, struct dir_context *ctx)
|
|
{
|
|
if (ctx->pos < FIRST_PROCESS_ENTRY) {
|
|
int error = proc_readdir(file, ctx);
|
|
if (unlikely(error <= 0))
|
|
return error;
|
|
ctx->pos = FIRST_PROCESS_ENTRY;
|
|
}
|
|
|
|
return proc_pid_readdir(file, ctx);
|
|
}
|
|
|
|
/*
|
|
* The root /proc directory is special, as it has the
|
|
* <pid> directories. Thus we don't use the generic
|
|
* directory handling functions for that..
|
|
*/
|
|
static const struct file_operations proc_root_operations = {
|
|
.read = generic_read_dir,
|
|
.iterate_shared = proc_root_readdir,
|
|
.llseek = generic_file_llseek,
|
|
};
|
|
|
|
/*
|
|
* proc root can do almost nothing..
|
|
*/
|
|
static const struct inode_operations proc_root_inode_operations = {
|
|
.lookup = proc_root_lookup,
|
|
.getattr = proc_root_getattr,
|
|
};
|
|
|
|
/*
|
|
* This is the root "inode" in the /proc tree..
|
|
*/
|
|
struct proc_dir_entry proc_root = {
|
|
.low_ino = PROC_ROOT_INO,
|
|
.namelen = 5,
|
|
.mode = S_IFDIR | S_IRUGO | S_IXUGO,
|
|
.nlink = 2,
|
|
.refcnt = REFCOUNT_INIT(1),
|
|
.proc_iops = &proc_root_inode_operations,
|
|
.proc_dir_ops = &proc_root_operations,
|
|
.parent = &proc_root,
|
|
.subdir = RB_ROOT,
|
|
.name = "/proc",
|
|
};
|