1 /* btrfs.c - B-tree file system. */
2 /*
3 * GRUB -- GRand Unified Bootloader
4 * Copyright (C) 2010 Free Software Foundation, Inc.
5 *
6 * GRUB is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
10 *
11 * GRUB is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include <grub/err.h>
21 #include <grub/file.h>
22 #include <grub/mm.h>
23 #include <grub/misc.h>
24 #include <grub/disk.h>
25 #include <grub/types.h>
26 #include <r_types.h>
27 #define BTRFS_SIGNATURE "_BHRfS_M"
28 R_PACKED(
29 struct btrfs_superblock
30 {
31 grub_uint8_t dummy1[32];
32 grub_uint16_t uuid[8];
33 grub_uint8_t dummy2[16];
34 grub_uint8_t signature[sizeof (BTRFS_SIGNATURE) - 1];
35 });
36
37 struct grub_btrfs_data
38 {
39 struct btrfs_superblock sblock;
40 };
41
42 static struct grub_btrfs_data *
grub_btrfs_mount(grub_disk_t disk)43 grub_btrfs_mount (grub_disk_t disk)
44 {
45 struct grub_btrfs_data *data = grub_malloc (sizeof (*data));
46 if (! data)
47 return NULL;
48
49 if (grub_disk_read (disk, 128, 0, sizeof (data->sblock),
50 &data->sblock) != GRUB_ERR_NONE)
51 goto fail;
52
53 if (grub_memcmp ((char *) data->sblock.signature, BTRFS_SIGNATURE, sizeof (BTRFS_SIGNATURE) - 1))
54 {
55 grub_error (GRUB_ERR_BAD_FS, "not a Btrfs filesystem");
56 goto fail;
57 }
58
59 return data;
60
61 fail:
62 grub_free (data);
63 return NULL;
64 }
65
66 static grub_err_t
grub_btrfs_open(struct grub_file * file,const char * name)67 grub_btrfs_open (struct grub_file *file ,
68 const char *name )
69 {
70 return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "only detection is supported for Btrfs");
71 }
72
73 static grub_err_t
grub_btrfs_dir(grub_device_t device,const char * path,int (* hook)(const char * filename,const struct grub_dirhook_info * info))74 grub_btrfs_dir (grub_device_t device,
75 const char *path ,
76 int (*hook) (const char *filename,
77 const struct grub_dirhook_info *info))
78 {
79 struct grub_btrfs_data *data = grub_btrfs_mount (device->disk);
80 if (grub_errno)
81 return grub_errno;
82 // TODO: no hook here? wtf?
83 grub_free (data);
84
85 return GRUB_ERR_NONE;
86 }
87
88 static grub_err_t
grub_btrfs_uuid(grub_device_t device,char ** uuid)89 grub_btrfs_uuid (grub_device_t device, char **uuid)
90 {
91 struct grub_btrfs_data *data;
92
93 *uuid = NULL;
94
95 data = grub_btrfs_mount (device->disk);
96 if (! data)
97 return grub_errno;
98
99 *uuid = grub_xasprintf ("%04x%04x-%04x-%04x-%04x-%04x%04x%04x",
100 grub_be_to_cpu16 (data->sblock.uuid[0]),
101 grub_be_to_cpu16 (data->sblock.uuid[1]),
102 grub_be_to_cpu16 (data->sblock.uuid[2]),
103 grub_be_to_cpu16 (data->sblock.uuid[3]),
104 grub_be_to_cpu16 (data->sblock.uuid[4]),
105 grub_be_to_cpu16 (data->sblock.uuid[5]),
106 grub_be_to_cpu16 (data->sblock.uuid[6]),
107 grub_be_to_cpu16 (data->sblock.uuid[7]));
108
109 grub_free (data);
110
111 return grub_errno;
112 }
113
114 struct grub_fs grub_btrfs_fs =
115 {
116 .name = "btrfs",
117 .dir = grub_btrfs_dir,
118 .open = grub_btrfs_open,
119 .uuid = grub_btrfs_uuid,
120 };
121