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115 lines
2.5 KiB
115 lines
2.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* fs/sysfs/symlink.c - operations for initializing and mounting sysfs |
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* |
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* Copyright (c) 2001-3 Patrick Mochel |
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* Copyright (c) 2007 SUSE Linux Products GmbH |
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* Copyright (c) 2007 Tejun Heo <[email protected]> |
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* |
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* Please see Documentation/filesystems/sysfs.rst for more information. |
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*/ |
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#include <linux/fs.h> |
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#include <linux/magic.h> |
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#include <linux/mount.h> |
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#include <linux/init.h> |
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#include <linux/slab.h> |
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#include <linux/user_namespace.h> |
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#include <linux/fs_context.h> |
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#include <net/net_namespace.h> |
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#include "sysfs.h" |
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static struct kernfs_root *sysfs_root; |
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struct kernfs_node *sysfs_root_kn; |
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static int sysfs_get_tree(struct fs_context *fc) |
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{ |
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struct kernfs_fs_context *kfc = fc->fs_private; |
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int ret; |
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ret = kernfs_get_tree(fc); |
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if (ret) |
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return ret; |
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if (kfc->new_sb_created) |
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fc->root->d_sb->s_iflags |= SB_I_USERNS_VISIBLE; |
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return 0; |
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} |
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static void sysfs_fs_context_free(struct fs_context *fc) |
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{ |
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struct kernfs_fs_context *kfc = fc->fs_private; |
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if (kfc->ns_tag) |
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kobj_ns_drop(KOBJ_NS_TYPE_NET, kfc->ns_tag); |
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kernfs_free_fs_context(fc); |
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kfree(kfc); |
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} |
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static const struct fs_context_operations sysfs_fs_context_ops = { |
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.free = sysfs_fs_context_free, |
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.get_tree = sysfs_get_tree, |
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}; |
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static int sysfs_init_fs_context(struct fs_context *fc) |
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{ |
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struct kernfs_fs_context *kfc; |
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struct net *netns; |
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if (!(fc->sb_flags & SB_KERNMOUNT)) { |
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if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET)) |
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return -EPERM; |
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} |
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kfc = kzalloc(sizeof(struct kernfs_fs_context), GFP_KERNEL); |
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if (!kfc) |
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return -ENOMEM; |
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kfc->ns_tag = netns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET); |
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kfc->root = sysfs_root; |
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kfc->magic = SYSFS_MAGIC; |
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fc->fs_private = kfc; |
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fc->ops = &sysfs_fs_context_ops; |
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if (netns) { |
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put_user_ns(fc->user_ns); |
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fc->user_ns = get_user_ns(netns->user_ns); |
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} |
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fc->global = true; |
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return 0; |
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} |
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static void sysfs_kill_sb(struct super_block *sb) |
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{ |
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void *ns = (void *)kernfs_super_ns(sb); |
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kernfs_kill_sb(sb); |
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kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); |
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} |
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static struct file_system_type sysfs_fs_type = { |
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.name = "sysfs", |
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.init_fs_context = sysfs_init_fs_context, |
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.kill_sb = sysfs_kill_sb, |
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.fs_flags = FS_USERNS_MOUNT, |
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}; |
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int __init sysfs_init(void) |
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{ |
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int err; |
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sysfs_root = kernfs_create_root(NULL, KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK, |
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NULL); |
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if (IS_ERR(sysfs_root)) |
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return PTR_ERR(sysfs_root); |
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sysfs_root_kn = sysfs_root->kn; |
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err = register_filesystem(&sysfs_fs_type); |
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if (err) { |
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kernfs_destroy_root(sysfs_root); |
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return err; |
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} |
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return 0; |
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}
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