1 /*
2 * No copyright is claimed. This code is in the public domain; do with
3 * it what you wish.
4 */
5 #ifndef UTIL_LINUX_LOOPDEV_H
6 #define UTIL_LINUX_LOOPDEV_H
7
8 #include "sysfs.h"
9
10 /*
11 * loop_info.lo_encrypt_type
12 */
13 #define LO_CRYPT_NONE 0
14 #define LO_CRYPT_XOR 1
15 #define LO_CRYPT_DES 2
16 #define LO_CRYPT_CRYPTOAPI 18
17
18 #define LOOP_SET_FD 0x4C00
19 #define LOOP_CLR_FD 0x4C01
20 /*
21 * Obsolete (kernel < 2.6)
22 *
23 * #define LOOP_SET_STATUS 0x4C02
24 * #define LOOP_GET_STATUS 0x4C03
25 */
26 #define LOOP_SET_STATUS64 0x4C04
27 #define LOOP_GET_STATUS64 0x4C05
28 /* #define LOOP_CHANGE_FD 0x4C06 */
29 #define LOOP_SET_CAPACITY 0x4C07
30 #define LOOP_SET_DIRECT_IO 0x4C08
31 #define LOOP_SET_BLOCK_SIZE 0x4C09
32
33 /* /dev/loop-control interface */
34 #ifndef LOOP_CTL_ADD
35 # define LOOP_CTL_ADD 0x4C80
36 # define LOOP_CTL_REMOVE 0x4C81
37 # define LOOP_CTL_GET_FREE 0x4C82
38 #endif
39
40 /*
41 * loop_info.lo_flags
42 */
43 enum {
44 LO_FLAGS_READ_ONLY = 1,
45 LO_FLAGS_USE_AOPS = 2,
46 LO_FLAGS_AUTOCLEAR = 4, /* kernel >= 2.6.25 */
47 LO_FLAGS_PARTSCAN = 8, /* kernel >= 3.2 */
48 LO_FLAGS_DIRECT_IO = 16, /* kernel >= 4.2 */
49 };
50
51 #define LO_NAME_SIZE 64
52 #define LO_KEY_SIZE 32
53
54 /*
55 * Linux LOOP_{SET,GET}_STATUS64 ioctl struct
56 */
57 struct loop_info64 {
58 uint64_t lo_device;
59 uint64_t lo_inode;
60 uint64_t lo_rdevice;
61 uint64_t lo_offset;
62 uint64_t lo_sizelimit; /* bytes, 0 == max available */
63 uint32_t lo_number;
64 uint32_t lo_encrypt_type;
65 uint32_t lo_encrypt_key_size;
66 uint32_t lo_flags;
67 uint8_t lo_file_name[LO_NAME_SIZE];
68 uint8_t lo_crypt_name[LO_NAME_SIZE];
69 uint8_t lo_encrypt_key[LO_KEY_SIZE];
70 uint64_t lo_init[2];
71 };
72
73 #ifndef LOOP_CONFIGURE
74 /*
75 * Since Linux v5.8-rc1 (commit 3448914e8cc550ba792d4ccc74471d1ca4293aae)
76 */
77 # define LOOP_CONFIGURE 0x4C0A
78 struct loop_config {
79 uint32_t fd;
80 uint32_t block_size;
81 struct loop_info64 info;
82 uint64_t __reserved[8];
83 };
84 #endif
85
86 #define LOOPDEV_MAJOR 7 /* loop major number */
87 #define LOOPDEV_DEFAULT_NNODES 8 /* default number of loop devices */
88
89 struct loopdev_iter {
90 FILE *proc; /* /proc/partitions */
91 DIR *sysblock; /* /sys/block */
92 int ncur; /* current position */
93 int *minors; /* ary of minor numbers (when scan whole /dev) */
94 int nminors; /* number of items in *minors */
95 int ct_perm; /* count permission problems */
96 int ct_succ; /* count number of detected devices */
97
98 unsigned int done:1; /* scanning done */
99 unsigned int default_check:1;/* check first LOOPDEV_NLOOPS */
100 int flags; /* LOOPITER_FL_* flags */
101 };
102
103 enum {
104 LOOPITER_FL_FREE = (1 << 0),
105 LOOPITER_FL_USED = (1 << 1)
106 };
107
108 /*
109 * handler for work with loop devices
110 */
111 struct loopdev_cxt {
112 char device[128]; /* device path (e.g. /dev/loop<N>) */
113 char *filename; /* backing file for loopcxt_set_... */
114 int fd; /* open(/dev/looo<N>) */
115 int mode; /* fd mode O_{RDONLY,RDWR} */
116 uint64_t blocksize; /* used by loopcxt_setup_device() */
117
118 int flags; /* LOOPDEV_FL_* flags */
119 unsigned int has_info:1; /* .info contains data */
120 unsigned int extra_check:1; /* unusual stuff for iterator */
121 unsigned int info_failed:1; /* LOOP_GET_STATUS ioctl failed */
122 unsigned int control_ok:1; /* /dev/loop-control success */
123
124 struct path_cxt *sysfs; /* pointer to /sys/dev/block/<maj:min>/ */
125 struct loop_config config; /* for GET/SET ioctl */
126 struct loopdev_iter iter; /* scans /sys or /dev for used/free devices */
127 };
128
129 #define UL_LOOPDEVCXT_EMPTY { .fd = -1 }
130
131 /*
132 * loopdev_cxt.flags
133 */
134 enum {
135 LOOPDEV_FL_RDONLY = (1 << 0), /* open(/dev/loop) mode; default */
136 LOOPDEV_FL_RDWR = (1 << 1), /* necessary for loop setup only */
137 LOOPDEV_FL_OFFSET = (1 << 4),
138 LOOPDEV_FL_NOSYSFS = (1 << 5),
139 LOOPDEV_FL_NOIOCTL = (1 << 6),
140 LOOPDEV_FL_DEVSUBDIR = (1 << 7),
141 LOOPDEV_FL_CONTROL = (1 << 8), /* system with /dev/loop-control */
142 LOOPDEV_FL_SIZELIMIT = (1 << 9)
143 };
144
145 /*
146 * High-level
147 */
148 extern int loopmod_supports_partscan(void);
149
150 extern int is_loopdev(const char *device);
151 extern int loopdev_is_autoclear(const char *device);
152
153 extern char *loopdev_get_backing_file(const char *device);
154 extern int loopdev_has_backing_file(const char *device);
155 extern int loopdev_is_used(const char *device, const char *filename,
156 uint64_t offset, uint64_t sizelimit, int flags);
157 extern char *loopdev_find_by_backing_file(const char *filename,
158 uint64_t offset, uint64_t sizelimit, int flags);
159 extern int loopcxt_find_unused(struct loopdev_cxt *lc);
160 extern int loopdev_delete(const char *device);
161 extern int loopdev_count_by_backing_file(const char *filename, char **loopdev);
162
163 /*
164 * Low-level
165 */
166 extern int loopcxt_init(struct loopdev_cxt *lc, int flags)
167 __attribute__ ((warn_unused_result));
168 extern void loopcxt_deinit(struct loopdev_cxt *lc);
169
170 extern int loopcxt_set_device(struct loopdev_cxt *lc, const char *device)
171 __attribute__ ((warn_unused_result));
172 extern int loopcxt_has_device(struct loopdev_cxt *lc);
173 extern int loopcxt_add_device(struct loopdev_cxt *lc);
174 extern char *loopcxt_strdup_device(struct loopdev_cxt *lc);
175 extern const char *loopcxt_get_device(struct loopdev_cxt *lc);
176 extern struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc);
177
178 extern int loopcxt_get_fd(struct loopdev_cxt *lc);
179 extern int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, int mode);
180
181 extern int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags);
182 extern int loopcxt_deinit_iterator(struct loopdev_cxt *lc);
183 extern int loopcxt_next(struct loopdev_cxt *lc);
184
185 extern int loopcxt_setup_device(struct loopdev_cxt *lc);
186 extern int loopcxt_delete_device(struct loopdev_cxt *lc);
187
188 extern int loopcxt_ioctl_status(struct loopdev_cxt *lc);
189 extern int loopcxt_ioctl_capacity(struct loopdev_cxt *lc);
190 extern int loopcxt_ioctl_dio(struct loopdev_cxt *lc, unsigned long use_dio);
191 extern int loopcxt_ioctl_blocksize(struct loopdev_cxt *lc, uint64_t blocksize);
192
193 int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset);
194 int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit);
195 int loopcxt_set_blocksize(struct loopdev_cxt *lc, uint64_t blocksize);
196 int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags);
197 int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename);
198
199 extern char *loopcxt_get_backing_file(struct loopdev_cxt *lc);
200 extern int loopcxt_get_backing_devno(struct loopdev_cxt *lc, dev_t *devno);
201 extern int loopcxt_get_backing_inode(struct loopdev_cxt *lc, ino_t *ino);
202 extern int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset);
203 extern int loopcxt_get_blocksize(struct loopdev_cxt *lc, uint64_t *blocksize);
204 extern int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size);
205 extern int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type);
206 extern const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc);
207 extern int loopcxt_is_autoclear(struct loopdev_cxt *lc);
208 extern int loopcxt_is_readonly(struct loopdev_cxt *lc);
209 extern int loopcxt_is_dio(struct loopdev_cxt *lc);
210 extern int loopcxt_is_partscan(struct loopdev_cxt *lc);
211 extern int loopcxt_find_by_backing_file(struct loopdev_cxt *lc,
212 const char *filename,
213 uint64_t offset, uint64_t sizelimit,
214 int flags);
215 extern int loopcxt_find_overlap(struct loopdev_cxt *lc,
216 const char *filename,
217 uint64_t offset, uint64_t sizelimit);
218
219 extern int loopcxt_is_used(struct loopdev_cxt *lc,
220 struct stat *st,
221 const char *backing_file,
222 uint64_t offset,
223 uint64_t sizelimit,
224 int flags);
225
226 #endif /* UTIL_LINUX_LOOPDEV_H */