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26#include <linux/module.h>
27#include <linux/fs.h>
28#include <linux/pagemap.h>
29#include <linux/highmem.h>
30#include <linux/time.h>
31#include <linux/init.h>
32#include <linux/string.h>
33#include <linux/backing-dev.h>
34#include <linux/ramfs.h>
35#include <linux/sched.h>
36#include <linux/parser.h>
37#include <linux/magic.h>
38#include <asm/uaccess.h>
39#include "internal.h"
40
41#define RAMFS_DEFAULT_MODE 0755
42
43static const struct super_operations ramfs_ops;
44static const struct inode_operations ramfs_dir_inode_operations;
45
46static struct backing_dev_info ramfs_backing_dev_info = {
47 .name = "ramfs",
48 .ra_pages = 0,
49 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK |
50 BDI_CAP_MAP_DIRECT | BDI_CAP_MAP_COPY |
51 BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP,
52};
53
54struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev)
55{
56 struct inode * inode = new_inode(sb);
57
58 if (inode) {
59 inode->i_mode = mode;
60 inode->i_uid = current_fsuid();
61 inode->i_gid = current_fsgid();
62 inode->i_mapping->a_ops = &ramfs_aops;
63 inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;
64 mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
65 mapping_set_unevictable(inode->i_mapping);
66 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
67 switch (mode & S_IFMT) {
68 default:
69 init_special_inode(inode, mode, dev);
70 break;
71 case S_IFREG:
72 inode->i_op = &ramfs_file_inode_operations;
73 inode->i_fop = &ramfs_file_operations;
74 break;
75 case S_IFDIR:
76 inode->i_op = &ramfs_dir_inode_operations;
77 inode->i_fop = &simple_dir_operations;
78
79
80 inc_nlink(inode);
81 break;
82 case S_IFLNK:
83 inode->i_op = &page_symlink_inode_operations;
84 break;
85 }
86 }
87 return inode;
88}
89
90
91
92
93
94static int
95ramfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
96{
97 struct inode * inode = ramfs_get_inode(dir->i_sb, mode, dev);
98 int error = -ENOSPC;
99
100 if (inode) {
101 if (dir->i_mode & S_ISGID) {
102 inode->i_gid = dir->i_gid;
103 if (S_ISDIR(mode))
104 inode->i_mode |= S_ISGID;
105 }
106 d_instantiate(dentry, inode);
107 dget(dentry);
108 error = 0;
109 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
110 }
111 return error;
112}
113
114static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
115{
116 int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
117 if (!retval)
118 inc_nlink(dir);
119 return retval;
120}
121
122static int ramfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
123{
124 return ramfs_mknod(dir, dentry, mode | S_IFREG, 0);
125}
126
127static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
128{
129 struct inode *inode;
130 int error = -ENOSPC;
131
132 inode = ramfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
133 if (inode) {
134 int l = strlen(symname)+1;
135 error = page_symlink(inode, symname, l);
136 if (!error) {
137 if (dir->i_mode & S_ISGID)
138 inode->i_gid = dir->i_gid;
139 d_instantiate(dentry, inode);
140 dget(dentry);
141 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
142 } else
143 iput(inode);
144 }
145 return error;
146}
147
148static const struct inode_operations ramfs_dir_inode_operations = {
149 .create = ramfs_create,
150 .lookup = simple_lookup,
151 .link = simple_link,
152 .unlink = simple_unlink,
153 .symlink = ramfs_symlink,
154 .mkdir = ramfs_mkdir,
155 .rmdir = simple_rmdir,
156 .mknod = ramfs_mknod,
157 .rename = simple_rename,
158};
159
160static const struct super_operations ramfs_ops = {
161 .statfs = simple_statfs,
162 .drop_inode = generic_delete_inode,
163 .show_options = generic_show_options,
164};
165
166struct ramfs_mount_opts {
167 umode_t mode;
168};
169
170enum {
171 Opt_mode,
172 Opt_err
173};
174
175static const match_table_t tokens = {
176 {Opt_mode, "mode=%o"},
177 {Opt_err, NULL}
178};
179
180struct ramfs_fs_info {
181 struct ramfs_mount_opts mount_opts;
182};
183
184static int ramfs_parse_options(char *data, struct ramfs_mount_opts *opts)
185{
186 substring_t args[MAX_OPT_ARGS];
187 int option;
188 int token;
189 char *p;
190
191 opts->mode = RAMFS_DEFAULT_MODE;
192
193 while ((p = strsep(&data, ",")) != NULL) {
194 if (!*p)
195 continue;
196
197 token = match_token(p, tokens, args);
198 switch (token) {
199 case Opt_mode:
200 if (match_octal(&args[0], &option))
201 return -EINVAL;
202 opts->mode = option & S_IALLUGO;
203 break;
204
205
206
207
208
209
210 }
211 }
212
213 return 0;
214}
215
216static int ramfs_fill_super(struct super_block * sb, void * data, int silent)
217{
218 struct ramfs_fs_info *fsi;
219 struct inode *inode = NULL;
220 struct dentry *root;
221 int err;
222
223 save_mount_options(sb, data);
224
225 fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL);
226 sb->s_fs_info = fsi;
227 if (!fsi) {
228 err = -ENOMEM;
229 goto fail;
230 }
231
232 err = ramfs_parse_options(data, &fsi->mount_opts);
233 if (err)
234 goto fail;
235
236 sb->s_maxbytes = MAX_LFS_FILESIZE;
237 sb->s_blocksize = PAGE_CACHE_SIZE;
238 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
239 sb->s_magic = RAMFS_MAGIC;
240 sb->s_op = &ramfs_ops;
241 sb->s_time_gran = 1;
242
243 inode = ramfs_get_inode(sb, S_IFDIR | fsi->mount_opts.mode, 0);
244 if (!inode) {
245 err = -ENOMEM;
246 goto fail;
247 }
248
249 root = d_alloc_root(inode);
250 sb->s_root = root;
251 if (!root) {
252 err = -ENOMEM;
253 goto fail;
254 }
255
256 return 0;
257fail:
258 kfree(fsi);
259 sb->s_fs_info = NULL;
260 iput(inode);
261 return err;
262}
263
264int ramfs_get_sb(struct file_system_type *fs_type,
265 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
266{
267 return get_sb_nodev(fs_type, flags, data, ramfs_fill_super, mnt);
268}
269
270static int rootfs_get_sb(struct file_system_type *fs_type,
271 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
272{
273 return get_sb_nodev(fs_type, flags|MS_NOUSER, data, ramfs_fill_super,
274 mnt);
275}
276
277static void ramfs_kill_sb(struct super_block *sb)
278{
279 kfree(sb->s_fs_info);
280 kill_litter_super(sb);
281}
282
283static struct file_system_type ramfs_fs_type = {
284 .name = "ramfs",
285 .get_sb = ramfs_get_sb,
286 .kill_sb = ramfs_kill_sb,
287};
288static struct file_system_type rootfs_fs_type = {
289 .name = "rootfs",
290 .get_sb = rootfs_get_sb,
291 .kill_sb = kill_litter_super,
292};
293
294static int __init init_ramfs_fs(void)
295{
296 return register_filesystem(&ramfs_fs_type);
297}
298
299static void __exit exit_ramfs_fs(void)
300{
301 unregister_filesystem(&ramfs_fs_type);
302}
303
304module_init(init_ramfs_fs)
305module_exit(exit_ramfs_fs)
306
307int __init init_rootfs(void)
308{
309 int err;
310
311 err = bdi_init(&ramfs_backing_dev_info);
312 if (err)
313 return err;
314
315 err = register_filesystem(&rootfs_fs_type);
316 if (err)
317 bdi_destroy(&ramfs_backing_dev_info);
318
319 return err;
320}
321
322MODULE_LICENSE("GPL");
323