~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/hostfs/hostfs_kern.c

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.77 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3  * Licensed under the GPL
  4  *
  5  * Ported the filesystem routines to 2.5.
  6  * 2003-02-10 Petr Baudis <pasky@ucw.cz>
  7  */
  8 
  9 #include <linux/fs.h>
 10 #include <linux/magic.h>
 11 #include <linux/module.h>
 12 #include <linux/mm.h>
 13 #include <linux/pagemap.h>
 14 #include <linux/statfs.h>
 15 #include <linux/slab.h>
 16 #include <linux/seq_file.h>
 17 #include <linux/mount.h>
 18 #include <linux/namei.h>
 19 #include "hostfs.h"
 20 #include <init.h>
 21 #include <kern.h>
 22 
 23 struct hostfs_inode_info {
 24         int fd;
 25         fmode_t mode;
 26         struct inode vfs_inode;
 27         struct mutex open_mutex;
 28 };
 29 
 30 static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
 31 {
 32         return list_entry(inode, struct hostfs_inode_info, vfs_inode);
 33 }
 34 
 35 #define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file))
 36 
 37 /* Changed in hostfs_args before the kernel starts running */
 38 static char *root_ino = "";
 39 static int append = 0;
 40 
 41 static const struct inode_operations hostfs_iops;
 42 static const struct inode_operations hostfs_dir_iops;
 43 static const struct inode_operations hostfs_link_iops;
 44 
 45 #ifndef MODULE
 46 static int __init hostfs_args(char *options, int *add)
 47 {
 48         char *ptr;
 49 
 50         ptr = strchr(options, ',');
 51         if (ptr != NULL)
 52                 *ptr++ = '\0';
 53         if (*options != '\0')
 54                 root_ino = options;
 55 
 56         options = ptr;
 57         while (options) {
 58                 ptr = strchr(options, ',');
 59                 if (ptr != NULL)
 60                         *ptr++ = '\0';
 61                 if (*options != '\0') {
 62                         if (!strcmp(options, "append"))
 63                                 append = 1;
 64                         else printf("hostfs_args - unsupported option - %s\n",
 65                                     options);
 66                 }
 67                 options = ptr;
 68         }
 69         return 0;
 70 }
 71 
 72 __uml_setup("hostfs=", hostfs_args,
 73 "hostfs=<root dir>,<flags>,...\n"
 74 "    This is used to set hostfs parameters.  The root directory argument\n"
 75 "    is used to confine all hostfs mounts to within the specified directory\n"
 76 "    tree on the host.  If this isn't specified, then a user inside UML can\n"
 77 "    mount anything on the host that's accessible to the user that's running\n"
 78 "    it.\n"
 79 "    The only flag currently supported is 'append', which specifies that all\n"
 80 "    files opened by hostfs will be opened in append mode.\n\n"
 81 );
 82 #endif
 83 
 84 static char *__dentry_name(struct dentry *dentry, char *name)
 85 {
 86         char *p = dentry_path_raw(dentry, name, PATH_MAX);
 87         char *root;
 88         size_t len;
 89 
 90         root = dentry->d_sb->s_fs_info;
 91         len = strlen(root);
 92         if (IS_ERR(p)) {
 93                 __putname(name);
 94                 return NULL;
 95         }
 96 
 97         /*
 98          * This function relies on the fact that dentry_path_raw() will place
 99          * the path name at the end of the provided buffer.
100          */
101         BUG_ON(p + strlen(p) + 1 != name + PATH_MAX);
102 
103         strlcpy(name, root, PATH_MAX);
104         if (len > p - name) {
105                 __putname(name);
106                 return NULL;
107         }
108 
109         if (p > name + len)
110                 strcpy(name + len, p);
111 
112         return name;
113 }
114 
115 static char *dentry_name(struct dentry *dentry)
116 {
117         char *name = __getname();
118         if (!name)
119                 return NULL;
120 
121         return __dentry_name(dentry, name);
122 }
123 
124 static char *inode_name(struct inode *ino)
125 {
126         struct dentry *dentry;
127         char *name;
128 
129         dentry = d_find_alias(ino);
130         if (!dentry)
131                 return NULL;
132 
133         name = dentry_name(dentry);
134 
135         dput(dentry);
136 
137         return name;
138 }
139 
140 static char *follow_link(char *link)
141 {
142         int len, n;
143         char *name, *resolved, *end;
144 
145         name = __getname();
146         if (!name) {
147                 n = -ENOMEM;
148                 goto out_free;
149         }
150 
151         n = hostfs_do_readlink(link, name, PATH_MAX);
152         if (n < 0)
153                 goto out_free;
154         else if (n == PATH_MAX) {
155                 n = -E2BIG;
156                 goto out_free;
157         }
158 
159         if (*name == '/')
160                 return name;
161 
162         end = strrchr(link, '/');
163         if (end == NULL)
164                 return name;
165 
166         *(end + 1) = '\0';
167         len = strlen(link) + strlen(name) + 1;
168 
169         resolved = kmalloc(len, GFP_KERNEL);
170         if (resolved == NULL) {
171                 n = -ENOMEM;
172                 goto out_free;
173         }
174 
175         sprintf(resolved, "%s%s", link, name);
176         __putname(name);
177         kfree(link);
178         return resolved;
179 
180  out_free:
181         __putname(name);
182         return ERR_PTR(n);
183 }
184 
185 static struct inode *hostfs_iget(struct super_block *sb)
186 {
187         struct inode *inode = new_inode(sb);
188         if (!inode)
189                 return ERR_PTR(-ENOMEM);
190         return inode;
191 }
192 
193 static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
194 {
195         /*
196          * do_statfs uses struct statfs64 internally, but the linux kernel
197          * struct statfs still has 32-bit versions for most of these fields,
198          * so we convert them here
199          */
200         int err;
201         long long f_blocks;
202         long long f_bfree;
203         long long f_bavail;
204         long long f_files;
205         long long f_ffree;
206 
207         err = do_statfs(dentry->d_sb->s_fs_info,
208                         &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
209                         &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
210                         &sf->f_namelen);
211         if (err)
212                 return err;
213         sf->f_blocks = f_blocks;
214         sf->f_bfree = f_bfree;
215         sf->f_bavail = f_bavail;
216         sf->f_files = f_files;
217         sf->f_ffree = f_ffree;
218         sf->f_type = HOSTFS_SUPER_MAGIC;
219         return 0;
220 }
221 
222 static struct inode *hostfs_alloc_inode(struct super_block *sb)
223 {
224         struct hostfs_inode_info *hi;
225 
226         hi = kmalloc(sizeof(*hi), GFP_KERNEL_ACCOUNT);
227         if (hi == NULL)
228                 return NULL;
229         hi->fd = -1;
230         hi->mode = 0;
231         inode_init_once(&hi->vfs_inode);
232         mutex_init(&hi->open_mutex);
233         return &hi->vfs_inode;
234 }
235 
236 static void hostfs_evict_inode(struct inode *inode)
237 {
238         truncate_inode_pages_final(&inode->i_data);
239         clear_inode(inode);
240         if (HOSTFS_I(inode)->fd != -1) {
241                 close_file(&HOSTFS_I(inode)->fd);
242                 HOSTFS_I(inode)->fd = -1;
243         }
244 }
245 
246 static void hostfs_i_callback(struct rcu_head *head)
247 {
248         struct inode *inode = container_of(head, struct inode, i_rcu);
249         kfree(HOSTFS_I(inode));
250 }
251 
252 static void hostfs_destroy_inode(struct inode *inode)
253 {
254         call_rcu(&inode->i_rcu, hostfs_i_callback);
255 }
256 
257 static int hostfs_show_options(struct seq_file *seq, struct dentry *root)
258 {
259         const char *root_path = root->d_sb->s_fs_info;
260         size_t offset = strlen(root_ino) + 1;
261 
262         if (strlen(root_path) > offset)
263                 seq_show_option(seq, root_path + offset, NULL);
264 
265         if (append)
266                 seq_puts(seq, ",append");
267 
268         return 0;
269 }
270 
271 static const struct super_operations hostfs_sbops = {
272         .alloc_inode    = hostfs_alloc_inode,
273         .destroy_inode  = hostfs_destroy_inode,
274         .evict_inode    = hostfs_evict_inode,
275         .statfs         = hostfs_statfs,
276         .show_options   = hostfs_show_options,
277 };
278 
279 static int hostfs_readdir(struct file *file, struct dir_context *ctx)
280 {
281         void *dir;
282         char *name;
283         unsigned long long next, ino;
284         int error, len;
285         unsigned int type;
286 
287         name = dentry_name(file->f_path.dentry);
288         if (name == NULL)
289                 return -ENOMEM;
290         dir = open_dir(name, &error);
291         __putname(name);
292         if (dir == NULL)
293                 return -error;
294         next = ctx->pos;
295         seek_dir(dir, next);
296         while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) {
297                 if (!dir_emit(ctx, name, len, ino, type))
298                         break;
299                 ctx->pos = next;
300         }
301         close_dir(dir);
302         return 0;
303 }
304 
305 static int hostfs_open(struct inode *ino, struct file *file)
306 {
307         char *name;
308         fmode_t mode;
309         int err;
310         int r, w, fd;
311 
312         mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
313         if ((mode & HOSTFS_I(ino)->mode) == mode)
314                 return 0;
315 
316         mode |= HOSTFS_I(ino)->mode;
317 
318 retry:
319         r = w = 0;
320 
321         if (mode & FMODE_READ)
322                 r = 1;
323         if (mode & FMODE_WRITE)
324                 r = w = 1;
325 
326         name = dentry_name(file->f_path.dentry);
327         if (name == NULL)
328                 return -ENOMEM;
329 
330         fd = open_file(name, r, w, append);
331         __putname(name);
332         if (fd < 0)
333                 return fd;
334 
335         mutex_lock(&HOSTFS_I(ino)->open_mutex);
336         /* somebody else had handled it first? */
337         if ((mode & HOSTFS_I(ino)->mode) == mode) {
338                 mutex_unlock(&HOSTFS_I(ino)->open_mutex);
339                 close_file(&fd);
340                 return 0;
341         }
342         if ((mode | HOSTFS_I(ino)->mode) != mode) {
343                 mode |= HOSTFS_I(ino)->mode;
344                 mutex_unlock(&HOSTFS_I(ino)->open_mutex);
345                 close_file(&fd);
346                 goto retry;
347         }
348         if (HOSTFS_I(ino)->fd == -1) {
349                 HOSTFS_I(ino)->fd = fd;
350         } else {
351                 err = replace_file(fd, HOSTFS_I(ino)->fd);
352                 close_file(&fd);
353                 if (err < 0) {
354                         mutex_unlock(&HOSTFS_I(ino)->open_mutex);
355                         return err;
356                 }
357         }
358         HOSTFS_I(ino)->mode = mode;
359         mutex_unlock(&HOSTFS_I(ino)->open_mutex);
360 
361         return 0;
362 }
363 
364 static int hostfs_file_release(struct inode *inode, struct file *file)
365 {
366         filemap_write_and_wait(inode->i_mapping);
367 
368         return 0;
369 }
370 
371 static int hostfs_fsync(struct file *file, loff_t start, loff_t end,
372                         int datasync)
373 {
374         struct inode *inode = file->f_mapping->host;
375         int ret;
376 
377         ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
378         if (ret)
379                 return ret;
380 
381         inode_lock(inode);
382         ret = fsync_file(HOSTFS_I(inode)->fd, datasync);
383         inode_unlock(inode);
384 
385         return ret;
386 }
387 
388 static const struct file_operations hostfs_file_fops = {
389         .llseek         = generic_file_llseek,
390         .splice_read    = generic_file_splice_read,
391         .read_iter      = generic_file_read_iter,
392         .write_iter     = generic_file_write_iter,
393         .mmap           = generic_file_mmap,
394         .open           = hostfs_open,
395         .release        = hostfs_file_release,
396         .fsync          = hostfs_fsync,
397 };
398 
399 static const struct file_operations hostfs_dir_fops = {
400         .llseek         = generic_file_llseek,
401         .iterate_shared = hostfs_readdir,
402         .read           = generic_read_dir,
403         .open           = hostfs_open,
404         .fsync          = hostfs_fsync,
405 };
406 
407 static int hostfs_writepage(struct page *page, struct writeback_control *wbc)
408 {
409         struct address_space *mapping = page->mapping;
410         struct inode *inode = mapping->host;
411         char *buffer;
412         loff_t base = page_offset(page);
413         int count = PAGE_SIZE;
414         int end_index = inode->i_size >> PAGE_SHIFT;
415         int err;
416 
417         if (page->index >= end_index)
418                 count = inode->i_size & (PAGE_SIZE-1);
419 
420         buffer = kmap(page);
421 
422         err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
423         if (err != count) {
424                 ClearPageUptodate(page);
425                 goto out;
426         }
427 
428         if (base > inode->i_size)
429                 inode->i_size = base;
430 
431         if (PageError(page))
432                 ClearPageError(page);
433         err = 0;
434 
435  out:
436         kunmap(page);
437 
438         unlock_page(page);
439         return err;
440 }
441 
442 static int hostfs_readpage(struct file *file, struct page *page)
443 {
444         char *buffer;
445         loff_t start = page_offset(page);
446         int bytes_read, ret = 0;
447 
448         buffer = kmap(page);
449         bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
450                         PAGE_SIZE);
451         if (bytes_read < 0) {
452                 ClearPageUptodate(page);
453                 SetPageError(page);
454                 ret = bytes_read;
455                 goto out;
456         }
457 
458         memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read);
459 
460         ClearPageError(page);
461         SetPageUptodate(page);
462 
463  out:
464         flush_dcache_page(page);
465         kunmap(page);
466         unlock_page(page);
467         return ret;
468 }
469 
470 static int hostfs_write_begin(struct file *file, struct address_space *mapping,
471                               loff_t pos, unsigned len, unsigned flags,
472                               struct page **pagep, void **fsdata)
473 {
474         pgoff_t index = pos >> PAGE_SHIFT;
475 
476         *pagep = grab_cache_page_write_begin(mapping, index, flags);
477         if (!*pagep)
478                 return -ENOMEM;
479         return 0;
480 }
481 
482 static int hostfs_write_end(struct file *file, struct address_space *mapping,
483                             loff_t pos, unsigned len, unsigned copied,
484                             struct page *page, void *fsdata)
485 {
486         struct inode *inode = mapping->host;
487         void *buffer;
488         unsigned from = pos & (PAGE_SIZE - 1);
489         int err;
490 
491         buffer = kmap(page);
492         err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied);
493         kunmap(page);
494 
495         if (!PageUptodate(page) && err == PAGE_SIZE)
496                 SetPageUptodate(page);
497 
498         /*
499          * If err > 0, write_file has added err to pos, so we are comparing
500          * i_size against the last byte written.
501          */
502         if (err > 0 && (pos > inode->i_size))
503                 inode->i_size = pos;
504         unlock_page(page);
505         put_page(page);
506 
507         return err;
508 }
509 
510 static const struct address_space_operations hostfs_aops = {
511         .writepage      = hostfs_writepage,
512         .readpage       = hostfs_readpage,
513         .set_page_dirty = __set_page_dirty_nobuffers,
514         .write_begin    = hostfs_write_begin,
515         .write_end      = hostfs_write_end,
516 };
517 
518 static int read_name(struct inode *ino, char *name)
519 {
520         dev_t rdev;
521         struct hostfs_stat st;
522         int err = stat_file(name, &st, -1);
523         if (err)
524                 return err;
525 
526         /* Reencode maj and min with the kernel encoding.*/
527         rdev = MKDEV(st.maj, st.min);
528 
529         switch (st.mode & S_IFMT) {
530         case S_IFLNK:
531                 ino->i_op = &hostfs_link_iops;
532                 break;
533         case S_IFDIR:
534                 ino->i_op = &hostfs_dir_iops;
535                 ino->i_fop = &hostfs_dir_fops;
536                 break;
537         case S_IFCHR:
538         case S_IFBLK:
539         case S_IFIFO:
540         case S_IFSOCK:
541                 init_special_inode(ino, st.mode & S_IFMT, rdev);
542                 ino->i_op = &hostfs_iops;
543                 break;
544         case S_IFREG:
545                 ino->i_op = &hostfs_iops;
546                 ino->i_fop = &hostfs_file_fops;
547                 ino->i_mapping->a_ops = &hostfs_aops;
548                 break;
549         default:
550                 return -EIO;
551         }
552 
553         ino->i_ino = st.ino;
554         ino->i_mode = st.mode;
555         set_nlink(ino, st.nlink);
556         i_uid_write(ino, st.uid);
557         i_gid_write(ino, st.gid);
558         ino->i_atime = st.atime;
559         ino->i_mtime = st.mtime;
560         ino->i_ctime = st.ctime;
561         ino->i_size = st.size;
562         ino->i_blocks = st.blocks;
563         return 0;
564 }
565 
566 static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
567                          bool excl)
568 {
569         struct inode *inode;
570         char *name;
571         int error, fd;
572 
573         inode = hostfs_iget(dir->i_sb);
574         if (IS_ERR(inode)) {
575                 error = PTR_ERR(inode);
576                 goto out;
577         }
578 
579         error = -ENOMEM;
580         name = dentry_name(dentry);
581         if (name == NULL)
582                 goto out_put;
583 
584         fd = file_create(name, mode & 0777);
585         if (fd < 0)
586                 error = fd;
587         else
588                 error = read_name(inode, name);
589 
590         __putname(name);
591         if (error)
592                 goto out_put;
593 
594         HOSTFS_I(inode)->fd = fd;
595         HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
596         d_instantiate(dentry, inode);
597         return 0;
598 
599  out_put:
600         iput(inode);
601  out:
602         return error;
603 }
604 
605 static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
606                                     unsigned int flags)
607 {
608         struct inode *inode;
609         char *name;
610         int err;
611 
612         inode = hostfs_iget(ino->i_sb);
613         if (IS_ERR(inode)) {
614                 err = PTR_ERR(inode);
615                 goto out;
616         }
617 
618         err = -ENOMEM;
619         name = dentry_name(dentry);
620         if (name == NULL)
621                 goto out_put;
622 
623         err = read_name(inode, name);
624 
625         __putname(name);
626         if (err == -ENOENT) {
627                 iput(inode);
628                 inode = NULL;
629         }
630         else if (err)
631                 goto out_put;
632 
633         d_add(dentry, inode);
634         return NULL;
635 
636  out_put:
637         iput(inode);
638  out:
639         return ERR_PTR(err);
640 }
641 
642 static int hostfs_link(struct dentry *to, struct inode *ino,
643                        struct dentry *from)
644 {
645         char *from_name, *to_name;
646         int err;
647 
648         if ((from_name = dentry_name(from)) == NULL)
649                 return -ENOMEM;
650         to_name = dentry_name(to);
651         if (to_name == NULL) {
652                 __putname(from_name);
653                 return -ENOMEM;
654         }
655         err = link_file(to_name, from_name);
656         __putname(from_name);
657         __putname(to_name);
658         return err;
659 }
660 
661 static int hostfs_unlink(struct inode *ino, struct dentry *dentry)
662 {
663         char *file;
664         int err;
665 
666         if (append)
667                 return -EPERM;
668 
669         if ((file = dentry_name(dentry)) == NULL)
670                 return -ENOMEM;
671 
672         err = unlink_file(file);
673         __putname(file);
674         return err;
675 }
676 
677 static int hostfs_symlink(struct inode *ino, struct dentry *dentry,
678                           const char *to)
679 {
680         char *file;
681         int err;
682 
683         if ((file = dentry_name(dentry)) == NULL)
684                 return -ENOMEM;
685         err = make_symlink(file, to);
686         __putname(file);
687         return err;
688 }
689 
690 static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode)
691 {
692         char *file;
693         int err;
694 
695         if ((file = dentry_name(dentry)) == NULL)
696                 return -ENOMEM;
697         err = do_mkdir(file, mode);
698         __putname(file);
699         return err;
700 }
701 
702 static int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
703 {
704         char *file;
705         int err;
706 
707         if ((file = dentry_name(dentry)) == NULL)
708                 return -ENOMEM;
709         err = do_rmdir(file);
710         __putname(file);
711         return err;
712 }
713 
714 static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
715 {
716         struct inode *inode;
717         char *name;
718         int err;
719 
720         inode = hostfs_iget(dir->i_sb);
721         if (IS_ERR(inode)) {
722                 err = PTR_ERR(inode);
723                 goto out;
724         }
725 
726         err = -ENOMEM;
727         name = dentry_name(dentry);
728         if (name == NULL)
729                 goto out_put;
730 
731         init_special_inode(inode, mode, dev);
732         err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
733         if (err)
734                 goto out_free;
735 
736         err = read_name(inode, name);
737         __putname(name);
738         if (err)
739                 goto out_put;
740 
741         d_instantiate(dentry, inode);
742         return 0;
743 
744  out_free:
745         __putname(name);
746  out_put:
747         iput(inode);
748  out:
749         return err;
750 }
751 
752 static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
753                           struct inode *new_dir, struct dentry *new_dentry,
754                           unsigned int flags)
755 {
756         char *old_name, *new_name;
757         int err;
758 
759         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
760                 return -EINVAL;
761 
762         old_name = dentry_name(old_dentry);
763         if (old_name == NULL)
764                 return -ENOMEM;
765         new_name = dentry_name(new_dentry);
766         if (new_name == NULL) {
767                 __putname(old_name);
768                 return -ENOMEM;
769         }
770         if (!flags)
771                 err = rename_file(old_name, new_name);
772         else
773                 err = rename2_file(old_name, new_name, flags);
774 
775         __putname(old_name);
776         __putname(new_name);
777         return err;
778 }
779 
780 static int hostfs_permission(struct inode *ino, int desired)
781 {
782         char *name;
783         int r = 0, w = 0, x = 0, err;
784 
785         if (desired & MAY_NOT_BLOCK)
786                 return -ECHILD;
787 
788         if (desired & MAY_READ) r = 1;
789         if (desired & MAY_WRITE) w = 1;
790         if (desired & MAY_EXEC) x = 1;
791         name = inode_name(ino);
792         if (name == NULL)
793                 return -ENOMEM;
794 
795         if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
796             S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
797                 err = 0;
798         else
799                 err = access_file(name, r, w, x);
800         __putname(name);
801         if (!err)
802                 err = generic_permission(ino, desired);
803         return err;
804 }
805 
806 static int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
807 {
808         struct inode *inode = d_inode(dentry);
809         struct hostfs_iattr attrs;
810         char *name;
811         int err;
812 
813         int fd = HOSTFS_I(inode)->fd;
814 
815         err = inode_change_ok(inode, attr);
816         if (err)
817                 return err;
818 
819         if (append)
820                 attr->ia_valid &= ~ATTR_SIZE;
821 
822         attrs.ia_valid = 0;
823         if (attr->ia_valid & ATTR_MODE) {
824                 attrs.ia_valid |= HOSTFS_ATTR_MODE;
825                 attrs.ia_mode = attr->ia_mode;
826         }
827         if (attr->ia_valid & ATTR_UID) {
828                 attrs.ia_valid |= HOSTFS_ATTR_UID;
829                 attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid);
830         }
831         if (attr->ia_valid & ATTR_GID) {
832                 attrs.ia_valid |= HOSTFS_ATTR_GID;
833                 attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid);
834         }
835         if (attr->ia_valid & ATTR_SIZE) {
836                 attrs.ia_valid |= HOSTFS_ATTR_SIZE;
837                 attrs.ia_size = attr->ia_size;
838         }
839         if (attr->ia_valid & ATTR_ATIME) {
840                 attrs.ia_valid |= HOSTFS_ATTR_ATIME;
841                 attrs.ia_atime = attr->ia_atime;
842         }
843         if (attr->ia_valid & ATTR_MTIME) {
844                 attrs.ia_valid |= HOSTFS_ATTR_MTIME;
845                 attrs.ia_mtime = attr->ia_mtime;
846         }
847         if (attr->ia_valid & ATTR_CTIME) {
848                 attrs.ia_valid |= HOSTFS_ATTR_CTIME;
849                 attrs.ia_ctime = attr->ia_ctime;
850         }
851         if (attr->ia_valid & ATTR_ATIME_SET) {
852                 attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
853         }
854         if (attr->ia_valid & ATTR_MTIME_SET) {
855                 attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
856         }
857         name = dentry_name(dentry);
858         if (name == NULL)
859                 return -ENOMEM;
860         err = set_attr(name, &attrs, fd);
861         __putname(name);
862         if (err)
863                 return err;
864 
865         if ((attr->ia_valid & ATTR_SIZE) &&
866             attr->ia_size != i_size_read(inode))
867                 truncate_setsize(inode, attr->ia_size);
868 
869         setattr_copy(inode, attr);
870         mark_inode_dirty(inode);
871         return 0;
872 }
873 
874 static const struct inode_operations hostfs_iops = {
875         .permission     = hostfs_permission,
876         .setattr        = hostfs_setattr,
877 };
878 
879 static const struct inode_operations hostfs_dir_iops = {
880         .create         = hostfs_create,
881         .lookup         = hostfs_lookup,
882         .link           = hostfs_link,
883         .unlink         = hostfs_unlink,
884         .symlink        = hostfs_symlink,
885         .mkdir          = hostfs_mkdir,
886         .rmdir          = hostfs_rmdir,
887         .mknod          = hostfs_mknod,
888         .rename2        = hostfs_rename2,
889         .permission     = hostfs_permission,
890         .setattr        = hostfs_setattr,
891 };
892 
893 static const char *hostfs_get_link(struct dentry *dentry,
894                                    struct inode *inode,
895                                    struct delayed_call *done)
896 {
897         char *link;
898         if (!dentry)
899                 return ERR_PTR(-ECHILD);
900         link = kmalloc(PATH_MAX, GFP_KERNEL);
901         if (link) {
902                 char *path = dentry_name(dentry);
903                 int err = -ENOMEM;
904                 if (path) {
905                         err = hostfs_do_readlink(path, link, PATH_MAX);
906                         if (err == PATH_MAX)
907                                 err = -E2BIG;
908                         __putname(path);
909                 }
910                 if (err < 0) {
911                         kfree(link);
912                         return ERR_PTR(err);
913                 }
914         } else {
915                 return ERR_PTR(-ENOMEM);
916         }
917 
918         set_delayed_call(done, kfree_link, link);
919         return link;
920 }
921 
922 static const struct inode_operations hostfs_link_iops = {
923         .readlink       = generic_readlink,
924         .get_link       = hostfs_get_link,
925 };
926 
927 static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
928 {
929         struct inode *root_inode;
930         char *host_root_path, *req_root = d;
931         int err;
932 
933         sb->s_blocksize = 1024;
934         sb->s_blocksize_bits = 10;
935         sb->s_magic = HOSTFS_SUPER_MAGIC;
936         sb->s_op = &hostfs_sbops;
937         sb->s_d_op = &simple_dentry_operations;
938         sb->s_maxbytes = MAX_LFS_FILESIZE;
939 
940         /* NULL is printed as <NULL> by sprintf: avoid that. */
941         if (req_root == NULL)
942                 req_root = "";
943 
944         err = -ENOMEM;
945         sb->s_fs_info = host_root_path =
946                 kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL);
947         if (host_root_path == NULL)
948                 goto out;
949 
950         sprintf(host_root_path, "%s/%s", root_ino, req_root);
951 
952         root_inode = new_inode(sb);
953         if (!root_inode)
954                 goto out;
955 
956         err = read_name(root_inode, host_root_path);
957         if (err)
958                 goto out_put;
959 
960         if (S_ISLNK(root_inode->i_mode)) {
961                 char *name = follow_link(host_root_path);
962                 if (IS_ERR(name)) {
963                         err = PTR_ERR(name);
964                         goto out_put;
965                 }
966                 err = read_name(root_inode, name);
967                 kfree(name);
968                 if (err)
969                         goto out_put;
970         }
971 
972         err = -ENOMEM;
973         sb->s_root = d_make_root(root_inode);
974         if (sb->s_root == NULL)
975                 goto out;
976 
977         return 0;
978 
979 out_put:
980         iput(root_inode);
981 out:
982         return err;
983 }
984 
985 static struct dentry *hostfs_read_sb(struct file_system_type *type,
986                           int flags, const char *dev_name,
987                           void *data)
988 {
989         return mount_nodev(type, flags, data, hostfs_fill_sb_common);
990 }
991 
992 static void hostfs_kill_sb(struct super_block *s)
993 {
994         kill_anon_super(s);
995         kfree(s->s_fs_info);
996 }
997 
998 static struct file_system_type hostfs_type = {
999         .owner          = THIS_MODULE,
1000         .name           = "hostfs",
1001         .mount          = hostfs_read_sb,
1002         .kill_sb        = hostfs_kill_sb,
1003         .fs_flags       = 0,
1004 };
1005 MODULE_ALIAS_FS("hostfs");
1006 
1007 static int __init init_hostfs(void)
1008 {
1009         return register_filesystem(&hostfs_type);
1010 }
1011 
1012 static void __exit exit_hostfs(void)
1013 {
1014         unregister_filesystem(&hostfs_type);
1015 }
1016 
1017 module_init(init_hostfs)
1018 module_exit(exit_hostfs)
1019 MODULE_LICENSE("GPL");
1020 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp