Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* -*- linux-c -*- --------------------------------------------------------- * |
2 | * | |
3 | * linux/fs/devpts/inode.c | |
4 | * | |
5 | * Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved | |
6 | * | |
7 | * This file is part of the Linux kernel and is made available under | |
8 | * the terms of the GNU General Public License, version 2, or at your | |
9 | * option, any later version, incorporated herein by reference. | |
10 | * | |
11 | * ------------------------------------------------------------------------- */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/namei.h> | |
18 | #include <linux/mount.h> | |
19 | #include <linux/tty.h> | |
20 | #include <linux/devpts_fs.h> | |
7a673c6b | 21 | #include <linux/parser.h> |
3972b7f6 | 22 | #include <linux/fsnotify.h> |
b87a267e | 23 | #include <linux/seq_file.h> |
1da177e4 LT |
24 | |
25 | #define DEVPTS_SUPER_MAGIC 0x1cd1 | |
26 | ||
b87a267e MS |
27 | #define DEVPTS_DEFAULT_MODE 0600 |
28 | ||
1da177e4 LT |
29 | static struct vfsmount *devpts_mnt; |
30 | static struct dentry *devpts_root; | |
31 | ||
32 | static struct { | |
33 | int setuid; | |
34 | int setgid; | |
35 | uid_t uid; | |
36 | gid_t gid; | |
37 | umode_t mode; | |
b87a267e | 38 | } config = {.mode = DEVPTS_DEFAULT_MODE}; |
1da177e4 | 39 | |
7a673c6b DP |
40 | enum { |
41 | Opt_uid, Opt_gid, Opt_mode, | |
42 | Opt_err | |
43 | }; | |
44 | ||
45 | static match_table_t tokens = { | |
46 | {Opt_uid, "uid=%u"}, | |
47 | {Opt_gid, "gid=%u"}, | |
48 | {Opt_mode, "mode=%o"}, | |
49 | {Opt_err, NULL} | |
50 | }; | |
51 | ||
1da177e4 LT |
52 | static int devpts_remount(struct super_block *sb, int *flags, char *data) |
53 | { | |
7a673c6b DP |
54 | char *p; |
55 | ||
56 | config.setuid = 0; | |
57 | config.setgid = 0; | |
58 | config.uid = 0; | |
59 | config.gid = 0; | |
b87a267e | 60 | config.mode = DEVPTS_DEFAULT_MODE; |
7a673c6b DP |
61 | |
62 | while ((p = strsep(&data, ",")) != NULL) { | |
63 | substring_t args[MAX_OPT_ARGS]; | |
64 | int token; | |
65 | int option; | |
66 | ||
67 | if (!*p) | |
1da177e4 | 68 | continue; |
7a673c6b DP |
69 | |
70 | token = match_token(p, tokens, args); | |
71 | switch (token) { | |
72 | case Opt_uid: | |
73 | if (match_int(&args[0], &option)) | |
74 | return -EINVAL; | |
75 | config.uid = option; | |
76 | config.setuid = 1; | |
77 | break; | |
78 | case Opt_gid: | |
79 | if (match_int(&args[0], &option)) | |
80 | return -EINVAL; | |
81 | config.gid = option; | |
82 | config.setgid = 1; | |
83 | break; | |
84 | case Opt_mode: | |
85 | if (match_octal(&args[0], &option)) | |
86 | return -EINVAL; | |
b87a267e | 87 | config.mode = option & S_IALLUGO; |
7a673c6b DP |
88 | break; |
89 | default: | |
90 | printk(KERN_ERR "devpts: called with bogus options\n"); | |
1da177e4 LT |
91 | return -EINVAL; |
92 | } | |
93 | } | |
1da177e4 LT |
94 | |
95 | return 0; | |
96 | } | |
97 | ||
b87a267e MS |
98 | static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs) |
99 | { | |
100 | if (config.setuid) | |
101 | seq_printf(seq, ",uid=%u", config.uid); | |
102 | if (config.setgid) | |
103 | seq_printf(seq, ",gid=%u", config.gid); | |
104 | seq_printf(seq, ",mode=%03o", config.mode); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
ee9b6d61 | 109 | static const struct super_operations devpts_sops = { |
1da177e4 LT |
110 | .statfs = simple_statfs, |
111 | .remount_fs = devpts_remount, | |
b87a267e | 112 | .show_options = devpts_show_options, |
1da177e4 LT |
113 | }; |
114 | ||
115 | static int | |
116 | devpts_fill_super(struct super_block *s, void *data, int silent) | |
117 | { | |
118 | struct inode * inode; | |
119 | ||
120 | s->s_blocksize = 1024; | |
121 | s->s_blocksize_bits = 10; | |
122 | s->s_magic = DEVPTS_SUPER_MAGIC; | |
123 | s->s_op = &devpts_sops; | |
1da177e4 LT |
124 | s->s_time_gran = 1; |
125 | ||
126 | inode = new_inode(s); | |
127 | if (!inode) | |
128 | goto fail; | |
129 | inode->i_ino = 1; | |
130 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
131 | inode->i_blocks = 0; | |
1da177e4 LT |
132 | inode->i_uid = inode->i_gid = 0; |
133 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; | |
134 | inode->i_op = &simple_dir_inode_operations; | |
135 | inode->i_fop = &simple_dir_operations; | |
136 | inode->i_nlink = 2; | |
137 | ||
138 | devpts_root = s->s_root = d_alloc_root(inode); | |
139 | if (s->s_root) | |
140 | return 0; | |
141 | ||
142 | printk("devpts: get root dentry failed\n"); | |
143 | iput(inode); | |
144 | fail: | |
145 | return -ENOMEM; | |
146 | } | |
147 | ||
454e2398 DH |
148 | static int devpts_get_sb(struct file_system_type *fs_type, |
149 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 150 | { |
454e2398 | 151 | return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt); |
1da177e4 LT |
152 | } |
153 | ||
154 | static struct file_system_type devpts_fs_type = { | |
155 | .owner = THIS_MODULE, | |
156 | .name = "devpts", | |
157 | .get_sb = devpts_get_sb, | |
158 | .kill_sb = kill_anon_super, | |
159 | }; | |
160 | ||
161 | /* | |
162 | * The normal naming convention is simply /dev/pts/<number>; this conforms | |
163 | * to the System V naming convention | |
164 | */ | |
165 | ||
166 | static struct dentry *get_node(int num) | |
167 | { | |
168 | char s[12]; | |
169 | struct dentry *root = devpts_root; | |
1b1dcc1b | 170 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
171 | return lookup_one_len(s, root, sprintf(s, "%d", num)); |
172 | } | |
173 | ||
174 | int devpts_pty_new(struct tty_struct *tty) | |
175 | { | |
176 | int number = tty->index; | |
177 | struct tty_driver *driver = tty->driver; | |
178 | dev_t device = MKDEV(driver->major, driver->minor_start+number); | |
179 | struct dentry *dentry; | |
180 | struct inode *inode = new_inode(devpts_mnt->mnt_sb); | |
181 | ||
182 | /* We're supposed to be given the slave end of a pty */ | |
183 | BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); | |
184 | BUG_ON(driver->subtype != PTY_TYPE_SLAVE); | |
185 | ||
186 | if (!inode) | |
187 | return -ENOMEM; | |
188 | ||
189 | inode->i_ino = number+2; | |
1da177e4 LT |
190 | inode->i_uid = config.setuid ? config.uid : current->fsuid; |
191 | inode->i_gid = config.setgid ? config.gid : current->fsgid; | |
192 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
193 | init_special_inode(inode, S_IFCHR|config.mode, device); | |
8e18e294 | 194 | inode->i_private = tty; |
1da177e4 LT |
195 | |
196 | dentry = get_node(number); | |
3972b7f6 | 197 | if (!IS_ERR(dentry) && !dentry->d_inode) { |
1da177e4 | 198 | d_instantiate(dentry, inode); |
3972b7f6 FM |
199 | fsnotify_create(devpts_root->d_inode, dentry); |
200 | } | |
1da177e4 | 201 | |
1b1dcc1b | 202 | mutex_unlock(&devpts_root->d_inode->i_mutex); |
1da177e4 LT |
203 | |
204 | return 0; | |
205 | } | |
206 | ||
207 | struct tty_struct *devpts_get_tty(int number) | |
208 | { | |
209 | struct dentry *dentry = get_node(number); | |
210 | struct tty_struct *tty; | |
211 | ||
212 | tty = NULL; | |
213 | if (!IS_ERR(dentry)) { | |
214 | if (dentry->d_inode) | |
8e18e294 | 215 | tty = dentry->d_inode->i_private; |
1da177e4 LT |
216 | dput(dentry); |
217 | } | |
218 | ||
1b1dcc1b | 219 | mutex_unlock(&devpts_root->d_inode->i_mutex); |
1da177e4 LT |
220 | |
221 | return tty; | |
222 | } | |
223 | ||
224 | void devpts_pty_kill(int number) | |
225 | { | |
226 | struct dentry *dentry = get_node(number); | |
227 | ||
228 | if (!IS_ERR(dentry)) { | |
229 | struct inode *inode = dentry->d_inode; | |
230 | if (inode) { | |
231 | inode->i_nlink--; | |
232 | d_delete(dentry); | |
233 | dput(dentry); | |
234 | } | |
235 | dput(dentry); | |
236 | } | |
1b1dcc1b | 237 | mutex_unlock(&devpts_root->d_inode->i_mutex); |
1da177e4 LT |
238 | } |
239 | ||
240 | static int __init init_devpts_fs(void) | |
241 | { | |
242 | int err = register_filesystem(&devpts_fs_type); | |
243 | if (!err) { | |
244 | devpts_mnt = kern_mount(&devpts_fs_type); | |
245 | if (IS_ERR(devpts_mnt)) | |
246 | err = PTR_ERR(devpts_mnt); | |
247 | } | |
248 | return err; | |
249 | } | |
250 | ||
251 | static void __exit exit_devpts_fs(void) | |
252 | { | |
253 | unregister_filesystem(&devpts_fs_type); | |
254 | mntput(devpts_mnt); | |
255 | } | |
256 | ||
257 | module_init(init_devpts_fs) | |
258 | module_exit(exit_devpts_fs) | |
259 | MODULE_LICENSE("GPL"); |