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Linux 3.16-rc2
[linux/fpc-iii.git] / fs / hppfs / hppfs.c
blob4338ff32959d4e9e3414bd9ed184d4d47b5a53fe
1 /*
2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6 #include <linux/ctype.h>
7 #include <linux/dcache.h>
8 #include <linux/file.h>
9 #include <linux/fs.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/list.h>
13 #include <linux/module.h>
14 #include <linux/mount.h>
15 #include <linux/slab.h>
16 #include <linux/statfs.h>
17 #include <linux/types.h>
18 #include <linux/pid_namespace.h>
19 #include <linux/namei.h>
20 #include <asm/uaccess.h>
21 #include <os.h>
22
23 static struct inode *get_inode(struct super_block *, struct dentry *);
24
25 struct hppfs_data {
26 struct list_head list;
27 char contents[PAGE_SIZE - sizeof(struct list_head)];
28 };
29
30 struct hppfs_private {
31 struct file *proc_file;
32 int host_fd;
33 loff_t len;
34 struct hppfs_data *contents;
35 };
36
37 struct hppfs_inode_info {
38 struct dentry *proc_dentry;
39 struct inode vfs_inode;
40 };
41
42 static inline struct hppfs_inode_info *HPPFS_I(struct inode *inode)
43 {
44 return container_of(inode, struct hppfs_inode_info, vfs_inode);
45 }
46
47 #define HPPFS_SUPER_MAGIC 0xb00000ee
48
49 static const struct super_operations hppfs_sbops;
50
51 static int is_pid(struct dentry *dentry)
52 {
53 struct super_block *sb;
54 int i;
55
56 sb = dentry->d_sb;
57 if (dentry->d_parent != sb->s_root)
58 return 0;
59
60 for (i = 0; i < dentry->d_name.len; i++) {
61 if (!isdigit(dentry->d_name.name[i]))
62 return 0;
63 }
64 return 1;
65 }
66
67 static char *dentry_name(struct dentry *dentry, int extra)
68 {
69 struct dentry *parent;
70 char *root, *name;
71 const char *seg_name;
72 int len, seg_len, root_len;
73
74 len = 0;
75 parent = dentry;
76 while (parent->d_parent != parent) {
77 if (is_pid(parent))
78 len += strlen("pid") + 1;
79 else len += parent->d_name.len + 1;
80 parent = parent->d_parent;
81 }
82
83 root = "proc";
84 root_len = strlen(root);
85 len += root_len;
86 name = kmalloc(len + extra + 1, GFP_KERNEL);
87 if (name == NULL)
88 return NULL;
89
90 name[len] = '\0';
91 parent = dentry;
92 while (parent->d_parent != parent) {
93 if (is_pid(parent)) {
94 seg_name = "pid";
95 seg_len = strlen(seg_name);
96 }
97 else {
98 seg_name = parent->d_name.name;
99 seg_len = parent->d_name.len;
100 }
101
102 len -= seg_len + 1;
103 name[len] = '/';
104 memcpy(&name[len + 1], seg_name, seg_len);
105 parent = parent->d_parent;
106 }
107 memcpy(name, root, root_len);
108 return name;
109 }
110
111 static int file_removed(struct dentry *dentry, const char *file)
112 {
113 char *host_file;
114 int extra, fd;
115
116 extra = 0;
117 if (file != NULL)
118 extra += strlen(file) + 1;
119
120 host_file = dentry_name(dentry, extra + strlen("/remove"));
121 if (host_file == NULL) {
122 printk(KERN_ERR "file_removed : allocation failed\n");
123 return -ENOMEM;
124 }
125
126 if (file != NULL) {
127 strcat(host_file, "/");
128 strcat(host_file, file);
129 }
130 strcat(host_file, "/remove");
131
132 fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
133 kfree(host_file);
134 if (fd > 0) {
135 os_close_file(fd);
136 return 1;
137 }
138 return 0;
139 }
140
141 static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
142 unsigned int flags)
143 {
144 struct dentry *proc_dentry, *parent;
145 struct qstr *name = &dentry->d_name;
146 struct inode *inode;
147 int err, deleted;
148
149 deleted = file_removed(dentry, NULL);
150 if (deleted < 0)
151 return ERR_PTR(deleted);
152 else if (deleted)
153 return ERR_PTR(-ENOENT);
154
155 parent = HPPFS_I(ino)->proc_dentry;
156 mutex_lock(&parent->d_inode->i_mutex);
157 proc_dentry = lookup_one_len(name->name, parent, name->len);
158 mutex_unlock(&parent->d_inode->i_mutex);
159
160 if (IS_ERR(proc_dentry))
161 return proc_dentry;
162
163 err = -ENOMEM;
164 inode = get_inode(ino->i_sb, proc_dentry);
165 if (!inode)
166 goto out;
167
168 d_add(dentry, inode);
169 return NULL;
170
171 out:
172 return ERR_PTR(err);
173 }
174
175 static const struct inode_operations hppfs_file_iops = {
176 };
177
178 static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
179 loff_t *ppos, int is_user)
180 {
181 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
182 ssize_t n;
183
184 read = file_inode(file)->i_fop->read;
185
186 if (!is_user)
187 set_fs(KERNEL_DS);
188
189 n = (*read)(file, buf, count, &file->f_pos);
190
191 if (!is_user)
192 set_fs(USER_DS);
193
194 if (ppos)
195 *ppos = file->f_pos;
196 return n;
197 }
198
199 static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
200 {
201 ssize_t n;
202 int cur, err;
203 char *new_buf;
204
205 n = -ENOMEM;
206 new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
207 if (new_buf == NULL) {
208 printk(KERN_ERR "hppfs_read_file : kmalloc failed\n");
209 goto out;
210 }
211 n = 0;
212 while (count > 0) {
213 cur = min_t(ssize_t, count, PAGE_SIZE);
214 err = os_read_file(fd, new_buf, cur);
215 if (err < 0) {
216 printk(KERN_ERR "hppfs_read : read failed, "
217 "errno = %d\n", err);
218 n = err;
219 goto out_free;
220 } else if (err == 0)
221 break;
222
223 if (copy_to_user(buf, new_buf, err)) {
224 n = -EFAULT;
225 goto out_free;
226 }
227 n += err;
228 count -= err;
229 }
230 out_free:
231 kfree(new_buf);
232 out:
233 return n;
234 }
235
236 static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
237 loff_t *ppos)
238 {
239 struct hppfs_private *hppfs = file->private_data;
240 struct hppfs_data *data;
241 loff_t off;
242 int err;
243
244 if (hppfs->contents != NULL) {
245 int rem;
246
247 if (*ppos >= hppfs->len)
248 return 0;
249
250 data = hppfs->contents;
251 off = *ppos;
252 while (off >= sizeof(data->contents)) {
253 data = list_entry(data->list.next, struct hppfs_data,
254 list);
255 off -= sizeof(data->contents);
256 }
257
258 if (off + count > hppfs->len)
259 count = hppfs->len - off;
260 rem = copy_to_user(buf, &data->contents[off], count);
261 *ppos += count - rem;
262 if (rem > 0)
263 return -EFAULT;
264 } else if (hppfs->host_fd != -1) {
265 err = os_seek_file(hppfs->host_fd, *ppos);
266 if (err) {
267 printk(KERN_ERR "hppfs_read : seek failed, "
268 "errno = %d\n", err);
269 return err;
270 }
271 err = hppfs_read_file(hppfs->host_fd, buf, count);
272 if (err < 0) {
273 printk(KERN_ERR "hppfs_read: read failed: %d\n", err);
274 return err;
275 }
276 count = err;
277 if (count > 0)
278 *ppos += count;
279 }
280 else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);
281
282 return count;
283 }
284
285 static ssize_t hppfs_write(struct file *file, const char __user *buf,
286 size_t len, loff_t *ppos)
287 {
288 struct hppfs_private *data = file->private_data;
289 struct file *proc_file = data->proc_file;
290 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
291
292 write = file_inode(proc_file)->i_fop->write;
293 return (*write)(proc_file, buf, len, ppos);
294 }
295
296 static int open_host_sock(char *host_file, int *filter_out)
297 {
298 char *end;
299 int fd;
300
301 end = &host_file[strlen(host_file)];
302 strcpy(end, "/rw");
303 *filter_out = 1;
304 fd = os_connect_socket(host_file);
305 if (fd > 0)
306 return fd;
307
308 strcpy(end, "/r");
309 *filter_out = 0;
310 fd = os_connect_socket(host_file);
311 return fd;
312 }
313
314 static void free_contents(struct hppfs_data *head)
315 {
316 struct hppfs_data *data;
317 struct list_head *ele, *next;
318
319 if (head == NULL)
320 return;
321
322 list_for_each_safe(ele, next, &head->list) {
323 data = list_entry(ele, struct hppfs_data, list);
324 kfree(data);
325 }
326 kfree(head);
327 }
328
329 static struct hppfs_data *hppfs_get_data(int fd, int filter,
330 struct file *proc_file,
331 struct file *hppfs_file,
332 loff_t *size_out)
333 {
334 struct hppfs_data *data, *new, *head;
335 int n, err;
336
337 err = -ENOMEM;
338 data = kmalloc(sizeof(*data), GFP_KERNEL);
339 if (data == NULL) {
340 printk(KERN_ERR "hppfs_get_data : head allocation failed\n");
341 goto failed;
342 }
343
344 INIT_LIST_HEAD(&data->list);
345
346 head = data;
347 *size_out = 0;
348
349 if (filter) {
350 while ((n = read_proc(proc_file, data->contents,
351 sizeof(data->contents), NULL, 0)) > 0)
352 os_write_file(fd, data->contents, n);
353 err = os_shutdown_socket(fd, 0, 1);
354 if (err) {
355 printk(KERN_ERR "hppfs_get_data : failed to shut down "
356 "socket\n");
357 goto failed_free;
358 }
359 }
360 while (1) {
361 n = os_read_file(fd, data->contents, sizeof(data->contents));
362 if (n < 0) {
363 err = n;
364 printk(KERN_ERR "hppfs_get_data : read failed, "
365 "errno = %d\n", err);
366 goto failed_free;
367 } else if (n == 0)
368 break;
369
370 *size_out += n;
371
372 if (n < sizeof(data->contents))
373 break;
374
375 new = kmalloc(sizeof(*data), GFP_KERNEL);
376 if (new == 0) {
377 printk(KERN_ERR "hppfs_get_data : data allocation "
378 "failed\n");
379 err = -ENOMEM;
380 goto failed_free;
381 }
382
383 INIT_LIST_HEAD(&new->list);
384 list_add(&new->list, &data->list);
385 data = new;
386 }
387 return head;
388
389 failed_free:
390 free_contents(head);
391 failed:
392 return ERR_PTR(err);
393 }
394
395 static struct hppfs_private *hppfs_data(void)
396 {
397 struct hppfs_private *data;
398
399 data = kmalloc(sizeof(*data), GFP_KERNEL);
400 if (data == NULL)
401 return data;
402
403 *data = ((struct hppfs_private ) { .host_fd = -1,
404 .len = -1,
405 .contents = NULL } );
406 return data;
407 }
408
409 static int file_mode(int fmode)
410 {
411 if (fmode == (FMODE_READ | FMODE_WRITE))
412 return O_RDWR;
413 if (fmode == FMODE_READ)
414 return O_RDONLY;
415 if (fmode == FMODE_WRITE)
416 return O_WRONLY;
417 return 0;
418 }
419
420 static int hppfs_open(struct inode *inode, struct file *file)
421 {
422 const struct cred *cred = file->f_cred;
423 struct hppfs_private *data;
424 struct path path;
425 char *host_file;
426 int err, fd, type, filter;
427
428 err = -ENOMEM;
429 data = hppfs_data();
430 if (data == NULL)
431 goto out;
432
433 host_file = dentry_name(file->f_path.dentry, strlen("/rw"));
434 if (host_file == NULL)
435 goto out_free2;
436
437 path.mnt = inode->i_sb->s_fs_info;
438 path.dentry = HPPFS_I(inode)->proc_dentry;
439
440 data->proc_file = dentry_open(&path, file_mode(file->f_mode), cred);
441 err = PTR_ERR(data->proc_file);
442 if (IS_ERR(data->proc_file))
443 goto out_free1;
444
445 type = os_file_type(host_file);
446 if (type == OS_TYPE_FILE) {
447 fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
448 if (fd >= 0)
449 data->host_fd = fd;
450 else
451 printk(KERN_ERR "hppfs_open : failed to open '%s', "
452 "errno = %d\n", host_file, -fd);
453
454 data->contents = NULL;
455 } else if (type == OS_TYPE_DIR) {
456 fd = open_host_sock(host_file, &filter);
457 if (fd > 0) {
458 data->contents = hppfs_get_data(fd, filter,
459 data->proc_file,
460 file, &data->len);
461 if (!IS_ERR(data->contents))
462 data->host_fd = fd;
463 } else
464 printk(KERN_ERR "hppfs_open : failed to open a socket "
465 "in '%s', errno = %d\n", host_file, -fd);
466 }
467 kfree(host_file);
468
469 file->private_data = data;
470 return 0;
471
472 out_free1:
473 kfree(host_file);
474 out_free2:
475 free_contents(data->contents);
476 kfree(data);
477 out:
478 return err;
479 }
480
481 static int hppfs_dir_open(struct inode *inode, struct file *file)
482 {
483 const struct cred *cred = file->f_cred;
484 struct hppfs_private *data;
485 struct path path;
486 int err;
487
488 err = -ENOMEM;
489 data = hppfs_data();
490 if (data == NULL)
491 goto out;
492
493 path.mnt = inode->i_sb->s_fs_info;
494 path.dentry = HPPFS_I(inode)->proc_dentry;
495 data->proc_file = dentry_open(&path, file_mode(file->f_mode), cred);
496 err = PTR_ERR(data->proc_file);
497 if (IS_ERR(data->proc_file))
498 goto out_free;
499
500 file->private_data = data;
501 return 0;
502
503 out_free:
504 kfree(data);
505 out:
506 return err;
507 }
508
509 static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
510 {
511 struct hppfs_private *data = file->private_data;
512 struct file *proc_file = data->proc_file;
513 loff_t (*llseek)(struct file *, loff_t, int);
514 loff_t ret;
515
516 llseek = file_inode(proc_file)->i_fop->llseek;
517 if (llseek != NULL) {
518 ret = (*llseek)(proc_file, off, where);
519 if (ret < 0)
520 return ret;
521 }
522
523 return default_llseek(file, off, where);
524 }
525
526 static int hppfs_release(struct inode *inode, struct file *file)
527 {
528 struct hppfs_private *data = file->private_data;
529 struct file *proc_file = data->proc_file;
530 if (proc_file)
531 fput(proc_file);
532 kfree(data);
533 return 0;
534 }
535
536 static const struct file_operations hppfs_file_fops = {
537 .owner = NULL,
538 .llseek = hppfs_llseek,
539 .read = hppfs_read,
540 .write = hppfs_write,
541 .open = hppfs_open,
542 .release = hppfs_release,
543 };
544
545 struct hppfs_dirent {
546 struct dir_context ctx;
547 struct dir_context *caller;
548 struct dentry *dentry;
549 };
550
551 static int hppfs_filldir(void *d, const char *name, int size,
552 loff_t offset, u64 inode, unsigned int type)
553 {
554 struct hppfs_dirent *dirent = d;
555
556 if (file_removed(dirent->dentry, name))
557 return 0;
558
559 dirent->caller->pos = dirent->ctx.pos;
560 return !dir_emit(dirent->caller, name, size, inode, type);
561 }
562
563 static int hppfs_readdir(struct file *file, struct dir_context *ctx)
564 {
565 struct hppfs_private *data = file->private_data;
566 struct file *proc_file = data->proc_file;
567 struct hppfs_dirent d = {
568 .ctx.actor = hppfs_filldir,
569 .caller = ctx,
570 .dentry = file->f_path.dentry
571 };
572 int err;
573 proc_file->f_pos = ctx->pos;
574 err = iterate_dir(proc_file, &d.ctx);
575 ctx->pos = d.ctx.pos;
576 return err;
577 }
578
579 static const struct file_operations hppfs_dir_fops = {
580 .owner = NULL,
581 .iterate = hppfs_readdir,
582 .open = hppfs_dir_open,
583 .llseek = default_llseek,
584 .release = hppfs_release,
585 };
586
587 static int hppfs_statfs(struct dentry *dentry, struct kstatfs *sf)
588 {
589 sf->f_blocks = 0;
590 sf->f_bfree = 0;
591 sf->f_bavail = 0;
592 sf->f_files = 0;
593 sf->f_ffree = 0;
594 sf->f_type = HPPFS_SUPER_MAGIC;
595 return 0;
596 }
597
598 static struct inode *hppfs_alloc_inode(struct super_block *sb)
599 {
600 struct hppfs_inode_info *hi;
601
602 hi = kmalloc(sizeof(*hi), GFP_KERNEL);
603 if (!hi)
604 return NULL;
605
606 hi->proc_dentry = NULL;
607 inode_init_once(&hi->vfs_inode);
608 return &hi->vfs_inode;
609 }
610
611 void hppfs_evict_inode(struct inode *ino)
612 {
613 clear_inode(ino);
614 dput(HPPFS_I(ino)->proc_dentry);
615 mntput(ino->i_sb->s_fs_info);
616 }
617
618 static void hppfs_i_callback(struct rcu_head *head)
619 {
620 struct inode *inode = container_of(head, struct inode, i_rcu);
621 kfree(HPPFS_I(inode));
622 }
623
624 static void hppfs_destroy_inode(struct inode *inode)
625 {
626 call_rcu(&inode->i_rcu, hppfs_i_callback);
627 }
628
629 static const struct super_operations hppfs_sbops = {
630 .alloc_inode = hppfs_alloc_inode,
631 .destroy_inode = hppfs_destroy_inode,
632 .evict_inode = hppfs_evict_inode,
633 .statfs = hppfs_statfs,
634 };
635
636 static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
637 int buflen)
638 {
639 struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
640 return proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer,
641 buflen);
642 }
643
644 static void *hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
645 {
646 struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
647
648 return proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
649 }
650
651 static void hppfs_put_link(struct dentry *dentry, struct nameidata *nd,
652 void *cookie)
653 {
654 struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
655
656 if (proc_dentry->d_inode->i_op->put_link)
657 proc_dentry->d_inode->i_op->put_link(proc_dentry, nd, cookie);
658 }
659
660 static const struct inode_operations hppfs_dir_iops = {
661 .lookup = hppfs_lookup,
662 };
663
664 static const struct inode_operations hppfs_link_iops = {
665 .readlink = hppfs_readlink,
666 .follow_link = hppfs_follow_link,
667 .put_link = hppfs_put_link,
668 };
669
670 static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
671 {
672 struct inode *proc_ino = dentry->d_inode;
673 struct inode *inode = new_inode(sb);
674
675 if (!inode) {
676 dput(dentry);
677 return NULL;
678 }
679
680 if (S_ISDIR(dentry->d_inode->i_mode)) {
681 inode->i_op = &hppfs_dir_iops;
682 inode->i_fop = &hppfs_dir_fops;
683 } else if (S_ISLNK(dentry->d_inode->i_mode)) {
684 inode->i_op = &hppfs_link_iops;
685 inode->i_fop = &hppfs_file_fops;
686 } else {
687 inode->i_op = &hppfs_file_iops;
688 inode->i_fop = &hppfs_file_fops;
689 }
690
691 HPPFS_I(inode)->proc_dentry = dentry;
692
693 inode->i_uid = proc_ino->i_uid;
694 inode->i_gid = proc_ino->i_gid;
695 inode->i_atime = proc_ino->i_atime;
696 inode->i_mtime = proc_ino->i_mtime;
697 inode->i_ctime = proc_ino->i_ctime;
698 inode->i_ino = proc_ino->i_ino;
699 inode->i_mode = proc_ino->i_mode;
700 set_nlink(inode, proc_ino->i_nlink);
701 inode->i_size = proc_ino->i_size;
702 inode->i_blocks = proc_ino->i_blocks;
703
704 return inode;
705 }
706
707 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
708 {
709 struct inode *root_inode;
710 struct vfsmount *proc_mnt;
711 int err = -ENOENT;
712
713 proc_mnt = mntget(task_active_pid_ns(current)->proc_mnt);
714 if (IS_ERR(proc_mnt))
715 goto out;
716
717 sb->s_blocksize = 1024;
718 sb->s_blocksize_bits = 10;
719 sb->s_magic = HPPFS_SUPER_MAGIC;
720 sb->s_op = &hppfs_sbops;
721 sb->s_fs_info = proc_mnt;
722
723 err = -ENOMEM;
724 root_inode = get_inode(sb, dget(proc_mnt->mnt_root));
725 sb->s_root = d_make_root(root_inode);
726 if (!sb->s_root)
727 goto out_mntput;
728
729 return 0;
730
731 out_mntput:
732 mntput(proc_mnt);
733 out:
734 return(err);
735 }
736
737 static struct dentry *hppfs_read_super(struct file_system_type *type,
738 int flags, const char *dev_name,
739 void *data)
740 {
741 return mount_nodev(type, flags, data, hppfs_fill_super);
742 }
743
744 static struct file_system_type hppfs_type = {
745 .owner = THIS_MODULE,
746 .name = "hppfs",
747 .mount = hppfs_read_super,
748 .kill_sb = kill_anon_super,
749 .fs_flags = 0,
750 };
751 MODULE_ALIAS_FS("hppfs");
752
753 static int __init init_hppfs(void)
754 {
755 return register_filesystem(&hppfs_type);
756 }
757
758 static void __exit exit_hppfs(void)
759 {
760 unregister_filesystem(&hppfs_type);
761 }
762
763 module_init(init_hppfs)
764 module_exit(exit_hppfs)
765 MODULE_LICENSE("GPL");
Linux with added FPC-III support