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