xref: /openbmc/linux/fs/proc/root.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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/init.h>
16 #include <linux/sched.h>
17 #include <linux/module.h>
18 #include <linux/bitops.h>
19 #include <linux/smp_lock.h>
20 #include <linux/mount.h>
21 
22 #include "internal.h"
23 
24 struct proc_dir_entry *proc_net, *proc_net_stat, *proc_bus, *proc_root_fs, *proc_root_driver;
25 
26 static int proc_get_sb(struct file_system_type *fs_type,
27 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
28 {
29 	if (proc_mnt) {
30 		/* Seed the root directory with a pid so it doesn't need
31 		 * to be special in base.c.  I would do this earlier but
32 		 * the only task alive when /proc is mounted the first time
33 		 * is the init_task and it doesn't have any pids.
34 		 */
35 		struct proc_inode *ei;
36 		ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode);
37 		if (!ei->pid)
38 			ei->pid = find_get_pid(1);
39 	}
40 	return get_sb_single(fs_type, flags, data, proc_fill_super, mnt);
41 }
42 
43 static struct file_system_type proc_fs_type = {
44 	.name		= "proc",
45 	.get_sb		= proc_get_sb,
46 	.kill_sb	= kill_anon_super,
47 };
48 
49 void __init proc_root_init(void)
50 {
51 	int err = proc_init_inodecache();
52 	if (err)
53 		return;
54 	err = register_filesystem(&proc_fs_type);
55 	if (err)
56 		return;
57 	proc_mnt = kern_mount(&proc_fs_type);
58 	err = PTR_ERR(proc_mnt);
59 	if (IS_ERR(proc_mnt)) {
60 		unregister_filesystem(&proc_fs_type);
61 		return;
62 	}
63 	proc_misc_init();
64 	proc_net = proc_mkdir("net", NULL);
65 	proc_net_stat = proc_mkdir("net/stat", NULL);
66 
67 #ifdef CONFIG_SYSVIPC
68 	proc_mkdir("sysvipc", NULL);
69 #endif
70 	proc_root_fs = proc_mkdir("fs", NULL);
71 	proc_root_driver = proc_mkdir("driver", NULL);
72 	proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
73 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
74 	/* just give it a mountpoint */
75 	proc_mkdir("openprom", NULL);
76 #endif
77 	proc_tty_init();
78 #ifdef CONFIG_PROC_DEVICETREE
79 	proc_device_tree_init();
80 #endif
81 	proc_bus = proc_mkdir("bus", NULL);
82 	proc_sys_init();
83 }
84 
85 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
86 )
87 {
88 	generic_fillattr(dentry->d_inode, stat);
89 	stat->nlink = proc_root.nlink + nr_processes();
90 	return 0;
91 }
92 
93 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
94 {
95 	if (!proc_lookup(dir, dentry, nd)) {
96 		return NULL;
97 	}
98 
99 	return proc_pid_lookup(dir, dentry, nd);
100 }
101 
102 static int proc_root_readdir(struct file * filp,
103 	void * dirent, filldir_t filldir)
104 {
105 	unsigned int nr = filp->f_pos;
106 	int ret;
107 
108 	lock_kernel();
109 
110 	if (nr < FIRST_PROCESS_ENTRY) {
111 		int error = proc_readdir(filp, dirent, filldir);
112 		if (error <= 0) {
113 			unlock_kernel();
114 			return error;
115 		}
116 		filp->f_pos = FIRST_PROCESS_ENTRY;
117 	}
118 	unlock_kernel();
119 
120 	ret = proc_pid_readdir(filp, dirent, filldir);
121 	return ret;
122 }
123 
124 /*
125  * The root /proc directory is special, as it has the
126  * <pid> directories. Thus we don't use the generic
127  * directory handling functions for that..
128  */
129 static const struct file_operations proc_root_operations = {
130 	.read		 = generic_read_dir,
131 	.readdir	 = proc_root_readdir,
132 };
133 
134 /*
135  * proc root can do almost nothing..
136  */
137 static const struct inode_operations proc_root_inode_operations = {
138 	.lookup		= proc_root_lookup,
139 	.getattr	= proc_root_getattr,
140 };
141 
142 /*
143  * This is the root "inode" in the /proc tree..
144  */
145 struct proc_dir_entry proc_root = {
146 	.low_ino	= PROC_ROOT_INO,
147 	.namelen	= 5,
148 	.name		= "/proc",
149 	.mode		= S_IFDIR | S_IRUGO | S_IXUGO,
150 	.nlink		= 2,
151 	.proc_iops	= &proc_root_inode_operations,
152 	.proc_fops	= &proc_root_operations,
153 	.parent		= &proc_root,
154 };
155 
156 EXPORT_SYMBOL(proc_symlink);
157 EXPORT_SYMBOL(proc_mkdir);
158 EXPORT_SYMBOL(create_proc_entry);
159 EXPORT_SYMBOL(remove_proc_entry);
160 EXPORT_SYMBOL(proc_root);
161 EXPORT_SYMBOL(proc_root_fs);
162 EXPORT_SYMBOL(proc_net);
163 EXPORT_SYMBOL(proc_net_stat);
164 EXPORT_SYMBOL(proc_bus);
165 EXPORT_SYMBOL(proc_root_driver);
166