1/*
2 * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
4 */
5
6#include <linux/fs.h>
7#include <linux/file.h>
8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/slab.h>
11#include <linux/list.h>
12#include <linux/kernel.h>
13#include <linux/ctype.h>
14#include <linux/dcache.h>
15#include <linux/statfs.h>
16#include <asm/uaccess.h>
17#include <asm/fcntl.h>
18#include "os.h"
19
20static int init_inode(struct inode *inode, struct dentry *dentry);
21
22struct hppfs_data {
23	struct list_head list;
24	char contents[PAGE_SIZE - sizeof(struct list_head)];
25};
26
27struct hppfs_private {
28	struct file *proc_file;
29	int host_fd;
30	loff_t len;
31	struct hppfs_data *contents;
32};
33
34struct hppfs_inode_info {
35        struct dentry *proc_dentry;
36	struct inode vfs_inode;
37};
38
39static inline struct hppfs_inode_info *HPPFS_I(struct inode *inode)
40{
41	return container_of(inode, struct hppfs_inode_info, vfs_inode);
42}
43
44#define HPPFS_SUPER_MAGIC 0xb00000ee
45
46static const struct super_operations hppfs_sbops;
47
48static int is_pid(struct dentry *dentry)
49{
50	struct super_block *sb;
51	int i;
52
53	sb = dentry->d_sb;
54	if((sb->s_op != &hppfs_sbops) || (dentry->d_parent != sb->s_root))
55		return(0);
56
57	for(i = 0; i < dentry->d_name.len; i++){
58		if(!isdigit(dentry->d_name.name[i]))
59			return(0);
60	}
61	return(1);
62}
63
64static char *dentry_name(struct dentry *dentry, int extra)
65{
66	struct dentry *parent;
67	char *root, *name;
68	const char *seg_name;
69	int len, seg_len;
70
71	len = 0;
72	parent = dentry;
73	while(parent->d_parent != parent){
74		if(is_pid(parent))
75			len += strlen("pid") + 1;
76		else len += parent->d_name.len + 1;
77		parent = parent->d_parent;
78	}
79
80	root = "proc";
81	len += strlen(root);
82	name = kmalloc(len + extra + 1, GFP_KERNEL);
83	if(name == NULL) return(NULL);
84
85	name[len] = '\0';
86	parent = dentry;
87	while(parent->d_parent != parent){
88		if(is_pid(parent)){
89			seg_name = "pid";
90			seg_len = strlen("pid");
91		}
92		else {
93			seg_name = parent->d_name.name;
94			seg_len = parent->d_name.len;
95		}
96
97		len -= seg_len + 1;
98		name[len] = '/';
99		strncpy(&name[len + 1], seg_name, seg_len);
100		parent = parent->d_parent;
101	}
102	strncpy(name, root, strlen(root));
103	return(name);
104}
105
106struct dentry_operations hppfs_dentry_ops = {
107};
108
109static int file_removed(struct dentry *dentry, const char *file)
110{
111	char *host_file;
112	int extra, fd;
113
114	extra = 0;
115	if(file != NULL) extra += strlen(file) + 1;
116
117	host_file = dentry_name(dentry, extra + strlen("/remove"));
118	if(host_file == NULL){
119		printk("file_removed : allocation failed\n");
120		return(-ENOMEM);
121	}
122
123	if(file != NULL){
124		strcat(host_file, "/");
125		strcat(host_file, file);
126	}
127	strcat(host_file, "/remove");
128
129	fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
130	kfree(host_file);
131	if(fd > 0){
132		os_close_file(fd);
133		return(1);
134	}
135	return(0);
136}
137
138static void hppfs_read_inode(struct inode *ino)
139{
140	struct inode *proc_ino;
141
142	if(HPPFS_I(ino)->proc_dentry == NULL)
143		return;
144
145	proc_ino = HPPFS_I(ino)->proc_dentry->d_inode;
146	ino->i_uid = proc_ino->i_uid;
147	ino->i_gid = proc_ino->i_gid;
148	ino->i_atime = proc_ino->i_atime;
149	ino->i_mtime = proc_ino->i_mtime;
150	ino->i_ctime = proc_ino->i_ctime;
151	ino->i_ino = proc_ino->i_ino;
152	ino->i_mode = proc_ino->i_mode;
153	ino->i_nlink = proc_ino->i_nlink;
154	ino->i_size = proc_ino->i_size;
155	ino->i_blocks = proc_ino->i_blocks;
156}
157
158static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
159                                  struct nameidata *nd)
160{
161	struct dentry *proc_dentry, *new, *parent;
162	struct inode *inode;
163	int err, deleted;
164
165	deleted = file_removed(dentry, NULL);
166	if(deleted < 0)
167		return(ERR_PTR(deleted));
168	else if(deleted)
169		return(ERR_PTR(-ENOENT));
170
171	err = -ENOMEM;
172	parent = HPPFS_I(ino)->proc_dentry;
173	mutex_lock(&parent->d_inode->i_mutex);
174	proc_dentry = d_lookup(parent, &dentry->d_name);
175	if(proc_dentry == NULL){
176		proc_dentry = d_alloc(parent, &dentry->d_name);
177		if(proc_dentry == NULL){
178			mutex_unlock(&parent->d_inode->i_mutex);
179			goto out;
180		}
181		new = (*parent->d_inode->i_op->lookup)(parent->d_inode,
182						       proc_dentry, NULL);
183		if(new){
184			dput(proc_dentry);
185			proc_dentry = new;
186		}
187	}
188	mutex_unlock(&parent->d_inode->i_mutex);
189
190	if(IS_ERR(proc_dentry))
191		return(proc_dentry);
192
193	inode = iget(ino->i_sb, 0);
194	if(inode == NULL)
195		goto out_dput;
196
197	err = init_inode(inode, proc_dentry);
198	if(err)
199		goto out_put;
200
201	hppfs_read_inode(inode);
202
203 	d_add(dentry, inode);
204	dentry->d_op = &hppfs_dentry_ops;
205	return(NULL);
206
207 out_put:
208	iput(inode);
209 out_dput:
210	dput(proc_dentry);
211 out:
212	return(ERR_PTR(err));
213}
214
215static const struct inode_operations hppfs_file_iops = {
216};
217
218static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
219			 loff_t *ppos, int is_user)
220{
221	ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
222	ssize_t n;
223
224	read = file->f_path.dentry->d_inode->i_fop->read;
225
226	if(!is_user)
227		set_fs(KERNEL_DS);
228
229	n = (*read)(file, buf, count, &file->f_pos);
230
231	if(!is_user)
232		set_fs(USER_DS);
233
234	if(ppos) *ppos = file->f_pos;
235	return n;
236}
237
238static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
239{
240	ssize_t n;
241	int cur, err;
242	char *new_buf;
243
244	n = -ENOMEM;
245	new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
246	if(new_buf == NULL){
247		printk("hppfs_read_file : kmalloc failed\n");
248		goto out;
249	}
250	n = 0;
251	while(count > 0){
252		cur = min_t(ssize_t, count, PAGE_SIZE);
253		err = os_read_file(fd, new_buf, cur);
254		if(err < 0){
255			printk("hppfs_read : read failed, errno = %d\n",
256			       err);
257			n = err;
258			goto out_free;
259		}
260		else if(err == 0)
261			break;
262
263		if(copy_to_user(buf, new_buf, err)){
264			n = -EFAULT;
265			goto out_free;
266		}
267		n += err;
268		count -= err;
269	}
270 out_free:
271	kfree(new_buf);
272 out:
273	return n;
274}
275
276static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
277			  loff_t *ppos)
278{
279	struct hppfs_private *hppfs = file->private_data;
280	struct hppfs_data *data;
281	loff_t off;
282	int err;
283
284	if(hppfs->contents != NULL){
285		if(*ppos >= hppfs->len) return(0);
286
287		data = hppfs->contents;
288		off = *ppos;
289		while(off >= sizeof(data->contents)){
290			data = list_entry(data->list.next, struct hppfs_data,
291					  list);
292			off -= sizeof(data->contents);
293		}
294
295		if(off + count > hppfs->len)
296			count = hppfs->len - off;
297		copy_to_user(buf, &data->contents[off], count);
298		*ppos += count;
299	}
300	else if(hppfs->host_fd != -1){
301		err = os_seek_file(hppfs->host_fd, *ppos);
302		if(err){
303			printk("hppfs_read : seek failed, errno = %d\n", err);
304			return(err);
305		}
306		count = hppfs_read_file(hppfs->host_fd, buf, count);
307		if(count > 0)
308			*ppos += count;
309	}
310	else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);
311
312	return(count);
313}
314
315static ssize_t hppfs_write(struct file *file, const char __user *buf, size_t len,
316			   loff_t *ppos)
317{
318	struct hppfs_private *data = file->private_data;
319	struct file *proc_file = data->proc_file;
320	ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
321	int err;
322
323	write = proc_file->f_path.dentry->d_inode->i_fop->write;
324
325	proc_file->f_pos = file->f_pos;
326	err = (*write)(proc_file, buf, len, &proc_file->f_pos);
327	file->f_pos = proc_file->f_pos;
328
329	return(err);
330}
331
332static int open_host_sock(char *host_file, int *filter_out)
333{
334	char *end;
335	int fd;
336
337	end = &host_file[strlen(host_file)];
338	strcpy(end, "/rw");
339	*filter_out = 1;
340	fd = os_connect_socket(host_file);
341	if(fd > 0)
342		return(fd);
343
344	strcpy(end, "/r");
345	*filter_out = 0;
346	fd = os_connect_socket(host_file);
347	return(fd);
348}
349
350static void free_contents(struct hppfs_data *head)
351{
352	struct hppfs_data *data;
353	struct list_head *ele, *next;
354
355	if(head == NULL) return;
356
357	list_for_each_safe(ele, next, &head->list){
358		data = list_entry(ele, struct hppfs_data, list);
359		kfree(data);
360	}
361	kfree(head);
362}
363
364static struct hppfs_data *hppfs_get_data(int fd, int filter,
365					 struct file *proc_file,
366					 struct file *hppfs_file,
367					 loff_t *size_out)
368{
369	struct hppfs_data *data, *new, *head;
370	int n, err;
371
372	err = -ENOMEM;
373	data = kmalloc(sizeof(*data), GFP_KERNEL);
374	if(data == NULL){
375		printk("hppfs_get_data : head allocation failed\n");
376		goto failed;
377	}
378
379	INIT_LIST_HEAD(&data->list);
380
381	head = data;
382	*size_out = 0;
383
384	if(filter){
385		while((n = read_proc(proc_file, data->contents,
386				     sizeof(data->contents), NULL, 0)) > 0)
387			os_write_file(fd, data->contents, n);
388		err = os_shutdown_socket(fd, 0, 1);
389		if(err){
390			printk("hppfs_get_data : failed to shut down "
391			       "socket\n");
392			goto failed_free;
393		}
394	}
395	while(1){
396		n = os_read_file(fd, data->contents, sizeof(data->contents));
397		if(n < 0){
398			err = n;
399			printk("hppfs_get_data : read failed, errno = %d\n",
400			       err);
401			goto failed_free;
402		}
403		else if(n == 0)
404			break;
405
406		*size_out += n;
407
408		if(n < sizeof(data->contents))
409			break;
410
411		new = kmalloc(sizeof(*data), GFP_KERNEL);
412		if(new == 0){
413			printk("hppfs_get_data : data allocation failed\n");
414			err = -ENOMEM;
415			goto failed_free;
416		}
417
418		INIT_LIST_HEAD(&new->list);
419		list_add(&new->list, &data->list);
420		data = new;
421	}
422	return(head);
423
424 failed_free:
425	free_contents(head);
426 failed:
427	return(ERR_PTR(err));
428}
429
430static struct hppfs_private *hppfs_data(void)
431{
432	struct hppfs_private *data;
433
434	data = kmalloc(sizeof(*data), GFP_KERNEL);
435	if(data == NULL)
436		return(data);
437
438	*data = ((struct hppfs_private ) { .host_fd  		= -1,
439					   .len  		= -1,
440					   .contents 		= NULL } );
441	return(data);
442}
443
444static int file_mode(int fmode)
445{
446	if(fmode == (FMODE_READ | FMODE_WRITE))
447		return(O_RDWR);
448	if(fmode == FMODE_READ)
449		return(O_RDONLY);
450	if(fmode == FMODE_WRITE)
451		return(O_WRONLY);
452	return(0);
453}
454
455static int hppfs_open(struct inode *inode, struct file *file)
456{
457	struct hppfs_private *data;
458	struct dentry *proc_dentry;
459	char *host_file;
460	int err, fd, type, filter;
461
462	err = -ENOMEM;
463	data = hppfs_data();
464	if(data == NULL)
465		goto out;
466
467	host_file = dentry_name(file->f_path.dentry, strlen("/rw"));
468	if(host_file == NULL)
469		goto out_free2;
470
471	proc_dentry = HPPFS_I(inode)->proc_dentry;
472
473	data->proc_file = dentry_open(dget(proc_dentry), NULL,
474				      file_mode(file->f_mode));
475	err = PTR_ERR(data->proc_file);
476	if(IS_ERR(data->proc_file))
477		goto out_free1;
478
479	type = os_file_type(host_file);
480	if(type == OS_TYPE_FILE){
481		fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
482		if(fd >= 0)
483			data->host_fd = fd;
484		else printk("hppfs_open : failed to open '%s', errno = %d\n",
485			    host_file, -fd);
486
487		data->contents = NULL;
488	}
489	else if(type == OS_TYPE_DIR){
490		fd = open_host_sock(host_file, &filter);
491		if(fd > 0){
492			data->contents = hppfs_get_data(fd, filter,
493							data->proc_file,
494							file, &data->len);
495			if(!IS_ERR(data->contents))
496				data->host_fd = fd;
497		}
498		else printk("hppfs_open : failed to open a socket in "
499			    "'%s', errno = %d\n", host_file, -fd);
500	}
501	kfree(host_file);
502
503	file->private_data = data;
504	return(0);
505
506 out_free1:
507	kfree(host_file);
508 out_free2:
509	free_contents(data->contents);
510	kfree(data);
511 out:
512	return(err);
513}
514
515static int hppfs_dir_open(struct inode *inode, struct file *file)
516{
517	struct hppfs_private *data;
518	struct dentry *proc_dentry;
519	int err;
520
521	err = -ENOMEM;
522	data = hppfs_data();
523	if(data == NULL)
524		goto out;
525
526	proc_dentry = HPPFS_I(inode)->proc_dentry;
527	data->proc_file = dentry_open(dget(proc_dentry), NULL,
528				      file_mode(file->f_mode));
529	err = PTR_ERR(data->proc_file);
530	if(IS_ERR(data->proc_file))
531		goto out_free;
532
533	file->private_data = data;
534	return(0);
535
536 out_free:
537	kfree(data);
538 out:
539	return(err);
540}
541
542static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
543{
544	struct hppfs_private *data = file->private_data;
545	struct file *proc_file = data->proc_file;
546	loff_t (*llseek)(struct file *, loff_t, int);
547	loff_t ret;
548
549	llseek = proc_file->f_path.dentry->d_inode->i_fop->llseek;
550	if(llseek != NULL){
551		ret = (*llseek)(proc_file, off, where);
552		if(ret < 0)
553			return(ret);
554	}
555
556	return(default_llseek(file, off, where));
557}
558
559static const struct file_operations hppfs_file_fops = {
560	.owner		= NULL,
561	.llseek		= hppfs_llseek,
562	.read		= hppfs_read,
563	.write		= hppfs_write,
564	.open		= hppfs_open,
565};
566
567struct hppfs_dirent {
568	void *vfs_dirent;
569	filldir_t filldir;
570	struct dentry *dentry;
571};
572
573static int hppfs_filldir(void *d, const char *name, int size,
574			 loff_t offset, u64 inode, unsigned int type)
575{
576	struct hppfs_dirent *dirent = d;
577
578	if(file_removed(dirent->dentry, name))
579		return(0);
580
581	return((*dirent->filldir)(dirent->vfs_dirent, name, size, offset,
582				  inode, type));
583}
584
585static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
586{
587	struct hppfs_private *data = file->private_data;
588	struct file *proc_file = data->proc_file;
589	int (*readdir)(struct file *, void *, filldir_t);
590	struct hppfs_dirent dirent = ((struct hppfs_dirent)
591		                      { .vfs_dirent  	= ent,
592					.filldir 	= filldir,
593					.dentry  	= file->f_path.dentry } );
594	int err;
595
596	readdir = proc_file->f_path.dentry->d_inode->i_fop->readdir;
597
598	proc_file->f_pos = file->f_pos;
599	err = (*readdir)(proc_file, &dirent, hppfs_filldir);
600	file->f_pos = proc_file->f_pos;
601
602	return(err);
603}
604
605static int hppfs_fsync(struct file *file, struct dentry *dentry, int datasync)
606{
607	return(0);
608}
609
610static const struct file_operations hppfs_dir_fops = {
611	.owner		= NULL,
612	.readdir	= hppfs_readdir,
613	.open		= hppfs_dir_open,
614	.fsync		= hppfs_fsync,
615};
616
617static int hppfs_statfs(struct dentry *dentry, struct kstatfs *sf)
618{
619	sf->f_blocks = 0;
620	sf->f_bfree = 0;
621	sf->f_bavail = 0;
622	sf->f_files = 0;
623	sf->f_ffree = 0;
624	sf->f_type = HPPFS_SUPER_MAGIC;
625	return(0);
626}
627
628static struct inode *hppfs_alloc_inode(struct super_block *sb)
629{
630	struct hppfs_inode_info *hi;
631
632	hi = kmalloc(sizeof(*hi), GFP_KERNEL);
633	if(hi == NULL)
634		return(NULL);
635
636	*hi = ((struct hppfs_inode_info) { .proc_dentry	= NULL });
637	inode_init_once(&hi->vfs_inode);
638	return(&hi->vfs_inode);
639}
640
641void hppfs_delete_inode(struct inode *ino)
642{
643	clear_inode(ino);
644}
645
646static void hppfs_destroy_inode(struct inode *inode)
647{
648	kfree(HPPFS_I(inode));
649}
650
651static const struct super_operations hppfs_sbops = {
652	.alloc_inode	= hppfs_alloc_inode,
653	.destroy_inode	= hppfs_destroy_inode,
654	.read_inode	= hppfs_read_inode,
655	.delete_inode	= hppfs_delete_inode,
656	.statfs		= hppfs_statfs,
657};
658
659static int hppfs_readlink(struct dentry *dentry, char __user *buffer, int buflen)
660{
661	struct file *proc_file;
662	struct dentry *proc_dentry;
663	int ret;
664
665	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
666	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
667	if (IS_ERR(proc_file))
668		return PTR_ERR(proc_file);
669
670	ret = proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer, buflen);
671
672	fput(proc_file);
673
674	return ret;
675}
676
677static void* hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
678{
679	struct file *proc_file;
680	struct dentry *proc_dentry;
681	void *ret;
682
683	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
684	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
685	if (IS_ERR(proc_file))
686		return proc_file;
687
688	ret = proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
689
690	fput(proc_file);
691
692	return ret;
693}
694
695static const struct inode_operations hppfs_dir_iops = {
696	.lookup		= hppfs_lookup,
697};
698
699static const struct inode_operations hppfs_link_iops = {
700	.readlink	= hppfs_readlink,
701	.follow_link	= hppfs_follow_link,
702};
703
704static int init_inode(struct inode *inode, struct dentry *dentry)
705{
706	if(S_ISDIR(dentry->d_inode->i_mode)){
707		inode->i_op = &hppfs_dir_iops;
708		inode->i_fop = &hppfs_dir_fops;
709	}
710	else if(S_ISLNK(dentry->d_inode->i_mode)){
711		inode->i_op = &hppfs_link_iops;
712		inode->i_fop = &hppfs_file_fops;
713	}
714	else {
715		inode->i_op = &hppfs_file_iops;
716		inode->i_fop = &hppfs_file_fops;
717	}
718
719	HPPFS_I(inode)->proc_dentry = dentry;
720
721	return(0);
722}
723
724static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
725{
726	struct inode *root_inode;
727	struct file_system_type *procfs;
728	struct super_block *proc_sb;
729	int err;
730
731	err = -ENOENT;
732	procfs = get_fs_type("proc");
733	if(procfs == NULL)
734		goto out;
735
736	if(list_empty(&procfs->fs_supers))
737		goto out;
738
739	proc_sb = list_entry(procfs->fs_supers.next, struct super_block,
740			     s_instances);
741
742	sb->s_blocksize = 1024;
743	sb->s_blocksize_bits = 10;
744	sb->s_magic = HPPFS_SUPER_MAGIC;
745	sb->s_op = &hppfs_sbops;
746
747	root_inode = iget(sb, 0);
748	if(root_inode == NULL)
749		goto out;
750
751	err = init_inode(root_inode, proc_sb->s_root);
752	if(err)
753		goto out_put;
754
755	err = -ENOMEM;
756	sb->s_root = d_alloc_root(root_inode);
757	if(sb->s_root == NULL)
758		goto out_put;
759
760	hppfs_read_inode(root_inode);
761
762	return(0);
763
764 out_put:
765	iput(root_inode);
766 out:
767	return(err);
768}
769
770static int hppfs_read_super(struct file_system_type *type,
771			    int flags, const char *dev_name,
772			    void *data, struct vfsmount *mnt)
773{
774	return get_sb_nodev(type, flags, data, hppfs_fill_super, mnt);
775}
776
777static struct file_system_type hppfs_type = {
778	.owner 		= THIS_MODULE,
779	.name 		= "hppfs",
780	.get_sb 	= hppfs_read_super,
781	.kill_sb	= kill_anon_super,
782	.fs_flags 	= 0,
783};
784
785static int __init init_hppfs(void)
786{
787	return(register_filesystem(&hppfs_type));
788}
789
790static void __exit exit_hppfs(void)
791{
792	unregister_filesystem(&hppfs_type);
793}
794
795module_init(init_hppfs)
796module_exit(exit_hppfs)
797MODULE_LICENSE("GPL");
798
799/*
800 * Overrides for Emacs so that we follow Linus's tabbing style.
801 * Emacs will notice this stuff at the end of the file and automatically
802 * adjust the settings for this buffer only.  This must remain at the end
803 * of the file.
804 * ---------------------------------------------------------------------------
805 * Local variables:
806 * c-file-style: "linux"
807 * End:
808 */
809