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