xref: /openbmc/linux/fs/proc/root.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  *  linux/fs/proc/root.c
3  *
4  *  Copyright (C) 1991, 1992 Linus Torvalds
5  *
6  *  proc root directory handling functions
7  */
8 
9 #include <asm/uaccess.h>
10 
11 #include <linux/errno.h>
12 #include <linux/time.h>
13 #include <linux/proc_fs.h>
14 #include <linux/stat.h>
15 #include <linux/config.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/bitops.h>
19 #include <linux/smp_lock.h>
20 
21 struct proc_dir_entry *proc_net, *proc_net_stat, *proc_bus, *proc_root_fs, *proc_root_driver;
22 
23 #ifdef CONFIG_SYSCTL
24 struct proc_dir_entry *proc_sys_root;
25 #endif
26 
27 static struct super_block *proc_get_sb(struct file_system_type *fs_type,
28 	int flags, const char *dev_name, void *data)
29 {
30 	return get_sb_single(fs_type, flags, data, proc_fill_super);
31 }
32 
33 static struct file_system_type proc_fs_type = {
34 	.name		= "proc",
35 	.get_sb		= proc_get_sb,
36 	.kill_sb	= kill_anon_super,
37 };
38 
39 extern int __init proc_init_inodecache(void);
40 void __init proc_root_init(void)
41 {
42 	int err = proc_init_inodecache();
43 	if (err)
44 		return;
45 	err = register_filesystem(&proc_fs_type);
46 	if (err)
47 		return;
48 	proc_mnt = kern_mount(&proc_fs_type);
49 	err = PTR_ERR(proc_mnt);
50 	if (IS_ERR(proc_mnt)) {
51 		unregister_filesystem(&proc_fs_type);
52 		return;
53 	}
54 	proc_misc_init();
55 	proc_net = proc_mkdir("net", NULL);
56 	proc_net_stat = proc_mkdir("net/stat", NULL);
57 
58 #ifdef CONFIG_SYSVIPC
59 	proc_mkdir("sysvipc", NULL);
60 #endif
61 #ifdef CONFIG_SYSCTL
62 	proc_sys_root = proc_mkdir("sys", NULL);
63 #endif
64 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
65 	proc_mkdir("sys/fs", NULL);
66 	proc_mkdir("sys/fs/binfmt_misc", NULL);
67 #endif
68 	proc_root_fs = proc_mkdir("fs", NULL);
69 	proc_root_driver = proc_mkdir("driver", NULL);
70 	proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
71 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
72 	/* just give it a mountpoint */
73 	proc_mkdir("openprom", NULL);
74 #endif
75 	proc_tty_init();
76 #ifdef CONFIG_PROC_DEVICETREE
77 	proc_device_tree_init();
78 #endif
79 	proc_bus = proc_mkdir("bus", NULL);
80 }
81 
82 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
83 {
84 	/*
85 	 * nr_threads is actually protected by the tasklist_lock;
86 	 * however, it's conventional to do reads, especially for
87 	 * reporting, without any locking whatsoever.
88 	 */
89 	if (dir->i_ino == PROC_ROOT_INO) /* check for safety... */
90 		dir->i_nlink = proc_root.nlink + nr_threads;
91 
92 	if (!proc_lookup(dir, dentry, nd)) {
93 		return NULL;
94 	}
95 
96 	return proc_pid_lookup(dir, dentry, nd);
97 }
98 
99 static int proc_root_readdir(struct file * filp,
100 	void * dirent, filldir_t filldir)
101 {
102 	unsigned int nr = filp->f_pos;
103 	int ret;
104 
105 	lock_kernel();
106 
107 	if (nr < FIRST_PROCESS_ENTRY) {
108 		int error = proc_readdir(filp, dirent, filldir);
109 		if (error <= 0) {
110 			unlock_kernel();
111 			return error;
112 		}
113 		filp->f_pos = FIRST_PROCESS_ENTRY;
114 	}
115 	unlock_kernel();
116 
117 	ret = proc_pid_readdir(filp, dirent, filldir);
118 	return ret;
119 }
120 
121 /*
122  * The root /proc directory is special, as it has the
123  * <pid> directories. Thus we don't use the generic
124  * directory handling functions for that..
125  */
126 static struct file_operations proc_root_operations = {
127 	.read		 = generic_read_dir,
128 	.readdir	 = proc_root_readdir,
129 };
130 
131 /*
132  * proc root can do almost nothing..
133  */
134 static struct inode_operations proc_root_inode_operations = {
135 	.lookup		= proc_root_lookup,
136 };
137 
138 /*
139  * This is the root "inode" in the /proc tree..
140  */
141 struct proc_dir_entry proc_root = {
142 	.low_ino	= PROC_ROOT_INO,
143 	.namelen	= 5,
144 	.name		= "/proc",
145 	.mode		= S_IFDIR | S_IRUGO | S_IXUGO,
146 	.nlink		= 2,
147 	.proc_iops	= &proc_root_inode_operations,
148 	.proc_fops	= &proc_root_operations,
149 	.parent		= &proc_root,
150 };
151 
152 EXPORT_SYMBOL(proc_symlink);
153 EXPORT_SYMBOL(proc_mkdir);
154 EXPORT_SYMBOL(create_proc_entry);
155 EXPORT_SYMBOL(remove_proc_entry);
156 EXPORT_SYMBOL(proc_root);
157 EXPORT_SYMBOL(proc_root_fs);
158 EXPORT_SYMBOL(proc_net);
159 EXPORT_SYMBOL(proc_net_stat);
160 EXPORT_SYMBOL(proc_bus);
161 EXPORT_SYMBOL(proc_root_driver);
162