include/loopdev.h

   1 #ifndef UTIL_LINUX_LOOPDEV_H
   2 #define UTIL_LINUX_LOOPDEV_H
   3
   4 #include "sysfs.h"
   5
   6 /*
   7  * loop_info.lo_encrypt_type
   8  */
   9 #define LO_CRYPT_NONE   0
  10 #define LO_CRYPT_XOR    1
  11 #define LO_CRYPT_DES    2
  12 #define LO_CRYPT_CRYPTOAPI 18
  13
  14 #define LOOP_SET_FD             0x4C00
  15 #define LOOP_CLR_FD             0x4C01
  16 /*
  17  * Obsolete (kernel < 2.6)
  18  *
  19  * #define LOOP_SET_STATUS      0x4C02
  20  * #define LOOP_GET_STATUS      0x4C03
  21  */
  22 #define LOOP_SET_STATUS64       0x4C04
  23 #define LOOP_GET_STATUS64       0x4C05
  24 /* #define LOOP_CHANGE_FD       0x4C06 */
  25 #define LOOP_SET_CAPACITY       0x4C07
  26 #define LOOP_SET_DIRECT_IO      0x4C08
  27 #define LOOP_SET_BLOCK_SIZE     0x4C09
  28
  29 /* /dev/loop-control interface */
  30 #ifndef LOOP_CTL_ADD
  31 # define LOOP_CTL_ADD           0x4C80
  32 # define LOOP_CTL_REMOVE        0x4C81
  33 # define LOOP_CTL_GET_FREE      0x4C82
  34 #endif
  35
  36 /*
  37  * loop_info.lo_flags
  38  */
  39 enum {
  40         LO_FLAGS_READ_ONLY  = 1,
  41         LO_FLAGS_USE_AOPS   = 2,
  42         LO_FLAGS_AUTOCLEAR  = 4,        /* kernel >= 2.6.25 */
  43         LO_FLAGS_PARTSCAN   = 8,        /* kernel >= 3.2 */
  44         LO_FLAGS_DIRECT_IO  = 16,       /* kernel >= 4.2 */
  45 };
  46
  47 #define LO_NAME_SIZE    64
  48 #define LO_KEY_SIZE     32
  49
  50 /*
  51  * Linux LOOP_{SET,GET}_STATUS64 ioctl struct
  52  */
  53 struct loop_info64 {
  54         uint64_t        lo_device;
  55         uint64_t        lo_inode;
  56         uint64_t        lo_rdevice;
  57         uint64_t        lo_offset;
  58         uint64_t        lo_sizelimit; /* bytes, 0 == max available */
  59         uint32_t        lo_number;
  60         uint32_t        lo_encrypt_type;
  61         uint32_t        lo_encrypt_key_size;
  62         uint32_t        lo_flags;
  63         uint8_t         lo_file_name[LO_NAME_SIZE];
  64         uint8_t         lo_crypt_name[LO_NAME_SIZE];
  65         uint8_t         lo_encrypt_key[LO_KEY_SIZE];
  66         uint64_t        lo_init[2];
  67 };
  68
  69 #define LOOPDEV_MAJOR           7       /* loop major number */
  70 #define LOOPDEV_DEFAULT_NNODES  8       /* default number of loop devices */
  71
  72 struct loopdev_iter {
  73         FILE            *proc;          /* /proc/partitions */
  74         DIR             *sysblock;      /* /sys/block */
  75         int             ncur;           /* current position */
  76         int             *minors;        /* ary of minor numbers (when scan whole /dev) */
  77         int             nminors;        /* number of items in *minors */
  78         int             ct_perm;        /* count permission problems */
  79         int             ct_succ;        /* count number of detected devices */
  80
  81         unsigned int    done:1;         /* scanning done */
  82         unsigned int    default_check:1;/* check first LOOPDEV_NLOOPS */
  83         int             flags;          /* LOOPITER_FL_* flags */
  84 };
  85
  86 enum {
  87         LOOPITER_FL_FREE        = (1 << 0),
  88         LOOPITER_FL_USED        = (1 << 1)
  89 };
  90
  91 /*
  92  * handler for work with loop devices
  93  */
  94 struct loopdev_cxt {
  95         char            device[128];    /* device path (e.g. /dev/loop<N>) */
  96         char            *filename;      /* backing file for loopcxt_set_... */
  97         int             fd;             /* open(/dev/looo<N>) */
  98         int             mode;           /* fd mode O_{RDONLY,RDWR} */
  99
 100         int             flags;          /* LOOPDEV_FL_* flags */
 101         unsigned int    has_info:1;     /* .info contains data */
 102         unsigned int    extra_check:1;  /* unusual stuff for iterator */
 103         unsigned int    info_failed:1;  /* LOOP_GET_STATUS ioctl failed */
 104         unsigned int    control_ok:1;   /* /dev/loop-control success */
 105
 106         struct path_cxt         *sysfs; /* pointer to /sys/dev/block/<maj:min>/ */
 107         struct loop_info64      info;   /* for GET/SET ioctl */
 108         struct loopdev_iter     iter;   /* scans /sys or /dev for used/free devices */
 109 };
 110
 111 #define UL_LOOPDEVCXT_EMPTY { .fd = -1  }
 112
 113 /*
 114  * loopdev_cxt.flags
 115  */
 116 enum {
 117         LOOPDEV_FL_RDONLY       = (1 << 0),     /* open(/dev/loop) mode; default */
 118         LOOPDEV_FL_RDWR         = (1 << 1),     /* necessary for loop setup only */
 119         LOOPDEV_FL_OFFSET       = (1 << 4),
 120         LOOPDEV_FL_NOSYSFS      = (1 << 5),
 121         LOOPDEV_FL_NOIOCTL      = (1 << 6),
 122         LOOPDEV_FL_DEVSUBDIR    = (1 << 7),
 123         LOOPDEV_FL_CONTROL      = (1 << 8),     /* system with /dev/loop-control */
 124         LOOPDEV_FL_SIZELIMIT    = (1 << 9)
 125 };
 126
 127 /*
 128  * High-level
 129  */
 130 extern int loopmod_supports_partscan(void);
 131
 132 extern int is_loopdev(const char *device);
 133 extern int loopdev_is_autoclear(const char *device);
 134
 135 extern char *loopdev_get_backing_file(const char *device);
 136 extern int loopdev_is_used(const char *device, const char *filename,
 137                            uint64_t offset, uint64_t sizelimit, int flags);
 138 extern char *loopdev_find_by_backing_file(const char *filename,
 139                                 uint64_t offset, uint64_t sizelimit, int flags);
 140 extern int loopcxt_find_unused(struct loopdev_cxt *lc);
 141 extern int loopdev_delete(const char *device);
 142 extern int loopdev_count_by_backing_file(const char *filename, char **loopdev);
 143
 144 /*
 145  * Low-level
 146  */
 147 extern int loopcxt_init(struct loopdev_cxt *lc, int flags)
 148                                 __attribute__ ((warn_unused_result));
 149 extern void loopcxt_deinit(struct loopdev_cxt *lc);
 150
 151 extern int loopcxt_set_device(struct loopdev_cxt *lc, const char *device)
 152                                 __attribute__ ((warn_unused_result));
 153 extern int loopcxt_has_device(struct loopdev_cxt *lc);
 154 extern int loopcxt_add_device(struct loopdev_cxt *lc);
 155 extern char *loopcxt_strdup_device(struct loopdev_cxt *lc);
 156 extern const char *loopcxt_get_device(struct loopdev_cxt *lc);
 157 extern struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc);
 158
 159 extern int loopcxt_get_fd(struct loopdev_cxt *lc);
 160 extern int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, int mode);
 161
 162 extern int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags);
 163 extern int loopcxt_deinit_iterator(struct loopdev_cxt *lc);
 164 extern int loopcxt_next(struct loopdev_cxt *lc);
 165
 166 extern int loopcxt_setup_device(struct loopdev_cxt *lc);
 167 extern int loopcxt_set_status(struct loopdev_cxt *lc);
 168 extern int loopcxt_delete_device(struct loopdev_cxt *lc);
 169 extern int loopcxt_set_capacity(struct loopdev_cxt *lc);
 170 extern int loopcxt_set_dio(struct loopdev_cxt *lc, unsigned long use_dio);
 171
 172 int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset);
 173 int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit);
 174 int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags);
 175 int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename);
 176 int loopcxt_set_blocksize(struct loopdev_cxt *lc, uint64_t blocksize);
 177
 178 extern char *loopcxt_get_backing_file(struct loopdev_cxt *lc);
 179 extern int loopcxt_get_backing_devno(struct loopdev_cxt *lc, dev_t *devno);
 180 extern int loopcxt_get_backing_inode(struct loopdev_cxt *lc, ino_t *ino);
 181 extern int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset);
 182 extern int loopcxt_get_blocksize(struct loopdev_cxt *lc, uint64_t *blocksize);
 183 extern int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size);
 184 extern int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type);
 185 extern const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc);
 186 extern int loopcxt_is_autoclear(struct loopdev_cxt *lc);
 187 extern int loopcxt_is_readonly(struct loopdev_cxt *lc);
 188 extern int loopcxt_is_dio(struct loopdev_cxt *lc);
 189 extern int loopcxt_is_partscan(struct loopdev_cxt *lc);
 190 extern int loopcxt_find_by_backing_file(struct loopdev_cxt *lc,
 191                                 const char *filename,
 192                                 uint64_t offset, uint64_t sizelimit,
 193                                 int flags);
 194 extern int loopcxt_find_overlap(struct loopdev_cxt *lc,
 195                                 const char *filename,
 196                                 uint64_t offset, uint64_t sizelimit);
 197
 198 extern int loopcxt_is_used(struct loopdev_cxt *lc,
 199                     struct stat *st,
 200                     const char *backing_file,
 201                     uint64_t offset,
 202                     uint64_t sizelimit,
 203                     int flags);
 204
 205 #endif /* UTIL_LINUX_LOOPDEV_H */