File: /usr/src/linux/fs/devpts/inode.c
1 /* -*- linux-c -*- --------------------------------------------------------- *
2 *
3 * linux/fs/devpts/inode.c
4 *
5 * Copyright 1998 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
15 #include <linux/string.h>
16 #include <linux/fs.h>
17 #include <linux/init.h>
18 #include <linux/kdev_t.h>
19 #include <linux/kernel.h>
20 #include <linux/locks.h>
21 #include <linux/major.h>
22 #include <linux/slab.h>
23 #include <linux/stat.h>
24 #include <linux/tty.h>
25 #include <asm/bitops.h>
26 #include <asm/uaccess.h>
27
28 #include "devpts_i.h"
29
30 static struct vfsmount *devpts_mnt;
31
32 static void devpts_put_super(struct super_block *sb)
33 {
34 struct devpts_sb_info *sbi = SBI(sb);
35 struct inode *inode;
36 int i;
37
38 for ( i = 0 ; i < sbi->max_ptys ; i++ ) {
39 if ( (inode = sbi->inodes[i]) ) {
40 if ( atomic_read(&inode->i_count) != 1 )
41 printk("devpts_put_super: badness: entry %d count %d\n",
42 i, atomic_read(&inode->i_count));
43 inode->i_nlink--;
44 iput(inode);
45 }
46 }
47 kfree(sbi->inodes);
48 kfree(sbi);
49 }
50
51 static int devpts_statfs(struct super_block *sb, struct statfs *buf);
52 static int devpts_remount (struct super_block * sb, int * flags, char * data);
53
54 static struct super_operations devpts_sops = {
55 put_super: devpts_put_super,
56 statfs: devpts_statfs,
57 remount_fs: devpts_remount,
58 };
59
60 static int devpts_parse_options(char *options, struct devpts_sb_info *sbi)
61 {
62 int setuid = 0;
63 int setgid = 0;
64 uid_t uid = 0;
65 gid_t gid = 0;
66 umode_t mode = 0600;
67 char *this_char, *value;
68
69 this_char = NULL;
70 if ( options )
71 this_char = strtok(options,",");
72 for ( ; this_char; this_char = strtok(NULL,",")) {
73 if ((value = strchr(this_char,'=')) != NULL)
74 *value++ = 0;
75 if (!strcmp(this_char,"uid")) {
76 if (!value || !*value)
77 return 1;
78 uid = simple_strtoul(value,&value,0);
79 if (*value)
80 return 1;
81 setuid = 1;
82 }
83 else if (!strcmp(this_char,"gid")) {
84 if (!value || !*value)
85 return 1;
86 gid = simple_strtoul(value,&value,0);
87 if (*value)
88 return 1;
89 setgid = 1;
90 }
91 else if (!strcmp(this_char,"mode")) {
92 if (!value || !*value)
93 return 1;
94 mode = simple_strtoul(value,&value,8);
95 if (*value)
96 return 1;
97 }
98 else
99 return 1;
100 }
101 sbi->setuid = setuid;
102 sbi->setgid = setgid;
103 sbi->uid = uid;
104 sbi->gid = gid;
105 sbi->mode = mode & ~S_IFMT;
106
107 return 0;
108 }
109
110 static int devpts_remount(struct super_block * sb, int * flags, char * data)
111 {
112 struct devpts_sb_info *sbi = sb->u.generic_sbp;
113 int res = devpts_parse_options(data,sbi);
114 if (res) {
115 printk("devpts: called with bogus options\n");
116 return -EINVAL;
117 }
118 return 0;
119 }
120
121 struct super_block *devpts_read_super(struct super_block *s, void *data,
122 int silent)
123 {
124 struct inode * inode;
125 struct devpts_sb_info *sbi;
126
127 sbi = (struct devpts_sb_info *) kmalloc(sizeof(struct devpts_sb_info), GFP_KERNEL);
128 if ( !sbi )
129 goto fail;
130
131 sbi->magic = DEVPTS_SBI_MAGIC;
132 sbi->max_ptys = unix98_max_ptys;
133 sbi->inodes = kmalloc(sizeof(struct inode *) * sbi->max_ptys, GFP_KERNEL);
134 if ( !sbi->inodes )
135 goto fail_free;
136 memset(sbi->inodes, 0, sizeof(struct inode *) * sbi->max_ptys);
137
138 if ( devpts_parse_options(data,sbi) && !silent) {
139 printk("devpts: called with bogus options\n");
140 goto fail_free;
141 }
142
143 inode = new_inode(s);
144 if (!inode)
145 goto fail_free;
146 inode->i_ino = 1;
147 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
148 inode->i_blocks = 0;
149 inode->i_blksize = 1024;
150 inode->i_uid = inode->i_gid = 0;
151 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
152 inode->i_op = &devpts_root_inode_operations;
153 inode->i_fop = &devpts_root_operations;
154 inode->i_nlink = 2;
155
156 s->u.generic_sbp = (void *) sbi;
157 s->s_blocksize = 1024;
158 s->s_blocksize_bits = 10;
159 s->s_magic = DEVPTS_SUPER_MAGIC;
160 s->s_op = &devpts_sops;
161 s->s_root = d_alloc_root(inode);
162 if (s->s_root)
163 return s;
164
165 printk("devpts: get root dentry failed\n");
166 iput(inode);
167 fail_free:
168 kfree(sbi);
169 fail:
170 return NULL;
171 }
172
173 static int devpts_statfs(struct super_block *sb, struct statfs *buf)
174 {
175 buf->f_type = DEVPTS_SUPER_MAGIC;
176 buf->f_bsize = 1024;
177 buf->f_namelen = NAME_MAX;
178 return 0;
179 }
180
181 static DECLARE_FSTYPE(devpts_fs_type, "devpts", devpts_read_super, FS_SINGLE);
182
183 void devpts_pty_new(int number, kdev_t device)
184 {
185 struct super_block *sb = devpts_mnt->mnt_sb;
186 struct devpts_sb_info *sbi = SBI(sb);
187 struct inode *inode;
188
189 if ( sbi->inodes[number] )
190 return; /* Already registered, this does happen */
191
192 inode = new_inode(sb);
193 if (!inode)
194 return;
195 inode->i_ino = number+2;
196 inode->i_blocks = 0;
197 inode->i_blksize = 1024;
198 inode->i_uid = sbi->setuid ? sbi->uid : current->fsuid;
199 inode->i_gid = sbi->setgid ? sbi->gid : current->fsgid;
200 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
201 init_special_inode(inode, S_IFCHR|sbi->mode, kdev_t_to_nr(device));
202
203 if ( sbi->inodes[number] ) {
204 iput(inode);
205 return;
206 }
207 sbi->inodes[number] = inode;
208 }
209
210 void devpts_pty_kill(int number)
211 {
212 struct super_block *sb = devpts_mnt->mnt_sb;
213 struct devpts_sb_info *sbi = SBI(sb);
214 struct inode *inode = sbi->inodes[number];
215
216 if ( inode ) {
217 sbi->inodes[number] = NULL;
218 inode->i_nlink--;
219 iput(inode);
220 }
221 }
222
223 static int __init init_devpts_fs(void)
224 {
225 int err = register_filesystem(&devpts_fs_type);
226 if (!err) {
227 devpts_mnt = kern_mount(&devpts_fs_type);
228 err = PTR_ERR(devpts_mnt);
229 if (!IS_ERR(devpts_mnt))
230 err = 0;
231 #ifdef MODULE
232 if ( !err ) {
233 devpts_upcall_new = devpts_pty_new;
234 devpts_upcall_kill = devpts_pty_kill;
235 }
236 #endif
237 }
238 return err;
239 }
240
241 static void __exit exit_devpts_fs(void)
242 {
243 #ifdef MODULE
244 devpts_upcall_new = NULL;
245 devpts_upcall_kill = NULL;
246 #endif
247 unregister_filesystem(&devpts_fs_type);
248 kern_umount(devpts_mnt);
249 }
250
251 module_init(init_devpts_fs)
252 module_exit(exit_devpts_fs)
253