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-rw-r--r--include/loopdev.h226
1 files changed, 226 insertions, 0 deletions
diff --git a/include/loopdev.h b/include/loopdev.h
new file mode 100644
index 0000000..903adc4
--- /dev/null
+++ b/include/loopdev.h
@@ -0,0 +1,226 @@
+/*
+ * No copyright is claimed. This code is in the public domain; do with
+ * it what you wish.
+ */
+#ifndef UTIL_LINUX_LOOPDEV_H
+#define UTIL_LINUX_LOOPDEV_H
+
+#include "sysfs.h"
+
+/*
+ * loop_info.lo_encrypt_type
+ */
+#define LO_CRYPT_NONE 0
+#define LO_CRYPT_XOR 1
+#define LO_CRYPT_DES 2
+#define LO_CRYPT_CRYPTOAPI 18
+
+#define LOOP_SET_FD 0x4C00
+#define LOOP_CLR_FD 0x4C01
+/*
+ * Obsolete (kernel < 2.6)
+ *
+ * #define LOOP_SET_STATUS 0x4C02
+ * #define LOOP_GET_STATUS 0x4C03
+ */
+#define LOOP_SET_STATUS64 0x4C04
+#define LOOP_GET_STATUS64 0x4C05
+/* #define LOOP_CHANGE_FD 0x4C06 */
+#define LOOP_SET_CAPACITY 0x4C07
+#define LOOP_SET_DIRECT_IO 0x4C08
+#define LOOP_SET_BLOCK_SIZE 0x4C09
+
+/* /dev/loop-control interface */
+#ifndef LOOP_CTL_ADD
+# define LOOP_CTL_ADD 0x4C80
+# define LOOP_CTL_REMOVE 0x4C81
+# define LOOP_CTL_GET_FREE 0x4C82
+#endif
+
+/*
+ * loop_info.lo_flags
+ */
+enum {
+ LO_FLAGS_READ_ONLY = 1,
+ LO_FLAGS_USE_AOPS = 2,
+ LO_FLAGS_AUTOCLEAR = 4, /* kernel >= 2.6.25 */
+ LO_FLAGS_PARTSCAN = 8, /* kernel >= 3.2 */
+ LO_FLAGS_DIRECT_IO = 16, /* kernel >= 4.2 */
+};
+
+#define LO_NAME_SIZE 64
+#define LO_KEY_SIZE 32
+
+/*
+ * Linux LOOP_{SET,GET}_STATUS64 ioctl struct
+ */
+struct loop_info64 {
+ uint64_t lo_device;
+ uint64_t lo_inode;
+ uint64_t lo_rdevice;
+ uint64_t lo_offset;
+ uint64_t lo_sizelimit; /* bytes, 0 == max available */
+ uint32_t lo_number;
+ uint32_t lo_encrypt_type;
+ uint32_t lo_encrypt_key_size;
+ uint32_t lo_flags;
+ uint8_t lo_file_name[LO_NAME_SIZE];
+ uint8_t lo_crypt_name[LO_NAME_SIZE];
+ uint8_t lo_encrypt_key[LO_KEY_SIZE];
+ uint64_t lo_init[2];
+};
+
+#ifndef LOOP_CONFIGURE
+/*
+ * Since Linux v5.8-rc1 (commit 3448914e8cc550ba792d4ccc74471d1ca4293aae)
+ */
+# define LOOP_CONFIGURE 0x4C0A
+struct loop_config {
+ uint32_t fd;
+ uint32_t block_size;
+ struct loop_info64 info;
+ uint64_t __reserved[8];
+};
+#endif
+
+#define LOOPDEV_MAJOR 7 /* loop major number */
+#define LOOPDEV_DEFAULT_NNODES 8 /* default number of loop devices */
+
+struct loopdev_iter {
+ FILE *proc; /* /proc/partitions */
+ DIR *sysblock; /* /sys/block */
+ int ncur; /* current position */
+ int *minors; /* ary of minor numbers (when scan whole /dev) */
+ int nminors; /* number of items in *minors */
+ int ct_perm; /* count permission problems */
+ int ct_succ; /* count number of detected devices */
+
+ unsigned int done:1; /* scanning done */
+ unsigned int default_check:1;/* check first LOOPDEV_NLOOPS */
+ int flags; /* LOOPITER_FL_* flags */
+};
+
+enum {
+ LOOPITER_FL_FREE = (1 << 0),
+ LOOPITER_FL_USED = (1 << 1)
+};
+
+/*
+ * handler for work with loop devices
+ */
+struct loopdev_cxt {
+ char device[128]; /* device path (e.g. /dev/loop<N>) */
+ char *filename; /* backing file for loopcxt_set_... */
+ int fd; /* open(/dev/looo<N>) */
+ int mode; /* fd mode O_{RDONLY,RDWR} */
+ uint64_t blocksize; /* used by loopcxt_setup_device() */
+
+ int flags; /* LOOPDEV_FL_* flags */
+ unsigned int has_info:1; /* .info contains data */
+ unsigned int extra_check:1; /* unusual stuff for iterator */
+ unsigned int info_failed:1; /* LOOP_GET_STATUS ioctl failed */
+ unsigned int control_ok:1; /* /dev/loop-control success */
+
+ struct path_cxt *sysfs; /* pointer to /sys/dev/block/<maj:min>/ */
+ struct loop_config config; /* for GET/SET ioctl */
+ struct loopdev_iter iter; /* scans /sys or /dev for used/free devices */
+};
+
+#define UL_LOOPDEVCXT_EMPTY { .fd = -1 }
+
+/*
+ * loopdev_cxt.flags
+ */
+enum {
+ LOOPDEV_FL_RDONLY = (1 << 0), /* open(/dev/loop) mode; default */
+ LOOPDEV_FL_RDWR = (1 << 1), /* necessary for loop setup only */
+ LOOPDEV_FL_OFFSET = (1 << 4),
+ LOOPDEV_FL_NOSYSFS = (1 << 5),
+ LOOPDEV_FL_NOIOCTL = (1 << 6),
+ LOOPDEV_FL_DEVSUBDIR = (1 << 7),
+ LOOPDEV_FL_CONTROL = (1 << 8), /* system with /dev/loop-control */
+ LOOPDEV_FL_SIZELIMIT = (1 << 9)
+};
+
+/*
+ * High-level
+ */
+extern int loopmod_supports_partscan(void);
+
+extern int is_loopdev(const char *device);
+extern int loopdev_is_autoclear(const char *device);
+
+extern char *loopdev_get_backing_file(const char *device);
+extern int loopdev_has_backing_file(const char *device);
+extern int loopdev_is_used(const char *device, const char *filename,
+ uint64_t offset, uint64_t sizelimit, int flags);
+extern char *loopdev_find_by_backing_file(const char *filename,
+ uint64_t offset, uint64_t sizelimit, int flags);
+extern int loopcxt_find_unused(struct loopdev_cxt *lc);
+extern int loopdev_delete(const char *device);
+extern int loopdev_count_by_backing_file(const char *filename, char **loopdev);
+
+/*
+ * Low-level
+ */
+extern int loopcxt_init(struct loopdev_cxt *lc, int flags)
+ __attribute__ ((warn_unused_result));
+extern void loopcxt_deinit(struct loopdev_cxt *lc);
+
+extern int loopcxt_set_device(struct loopdev_cxt *lc, const char *device)
+ __attribute__ ((warn_unused_result));
+extern int loopcxt_has_device(struct loopdev_cxt *lc);
+extern int loopcxt_add_device(struct loopdev_cxt *lc);
+extern char *loopcxt_strdup_device(struct loopdev_cxt *lc);
+extern const char *loopcxt_get_device(struct loopdev_cxt *lc);
+extern struct loop_info64 *loopcxt_get_info(struct loopdev_cxt *lc);
+
+extern int loopcxt_get_fd(struct loopdev_cxt *lc);
+extern int loopcxt_set_fd(struct loopdev_cxt *lc, int fd, int mode);
+
+extern int loopcxt_init_iterator(struct loopdev_cxt *lc, int flags);
+extern int loopcxt_deinit_iterator(struct loopdev_cxt *lc);
+extern int loopcxt_next(struct loopdev_cxt *lc);
+
+extern int loopcxt_setup_device(struct loopdev_cxt *lc);
+extern int loopcxt_delete_device(struct loopdev_cxt *lc);
+
+extern int loopcxt_ioctl_status(struct loopdev_cxt *lc);
+extern int loopcxt_ioctl_capacity(struct loopdev_cxt *lc);
+extern int loopcxt_ioctl_dio(struct loopdev_cxt *lc, unsigned long use_dio);
+extern int loopcxt_ioctl_blocksize(struct loopdev_cxt *lc, uint64_t blocksize);
+
+int loopcxt_set_offset(struct loopdev_cxt *lc, uint64_t offset);
+int loopcxt_set_sizelimit(struct loopdev_cxt *lc, uint64_t sizelimit);
+int loopcxt_set_blocksize(struct loopdev_cxt *lc, uint64_t blocksize);
+int loopcxt_set_flags(struct loopdev_cxt *lc, uint32_t flags);
+int loopcxt_set_backing_file(struct loopdev_cxt *lc, const char *filename);
+
+extern char *loopcxt_get_backing_file(struct loopdev_cxt *lc);
+extern int loopcxt_get_backing_devno(struct loopdev_cxt *lc, dev_t *devno);
+extern int loopcxt_get_backing_inode(struct loopdev_cxt *lc, ino_t *ino);
+extern int loopcxt_get_offset(struct loopdev_cxt *lc, uint64_t *offset);
+extern int loopcxt_get_blocksize(struct loopdev_cxt *lc, uint64_t *blocksize);
+extern int loopcxt_get_sizelimit(struct loopdev_cxt *lc, uint64_t *size);
+extern int loopcxt_get_encrypt_type(struct loopdev_cxt *lc, uint32_t *type);
+extern const char *loopcxt_get_crypt_name(struct loopdev_cxt *lc);
+extern int loopcxt_is_autoclear(struct loopdev_cxt *lc);
+extern int loopcxt_is_readonly(struct loopdev_cxt *lc);
+extern int loopcxt_is_dio(struct loopdev_cxt *lc);
+extern int loopcxt_is_partscan(struct loopdev_cxt *lc);
+extern int loopcxt_find_by_backing_file(struct loopdev_cxt *lc,
+ const char *filename,
+ uint64_t offset, uint64_t sizelimit,
+ int flags);
+extern int loopcxt_find_overlap(struct loopdev_cxt *lc,
+ const char *filename,
+ uint64_t offset, uint64_t sizelimit);
+
+extern int loopcxt_is_used(struct loopdev_cxt *lc,
+ struct stat *st,
+ const char *backing_file,
+ uint64_t offset,
+ uint64_t sizelimit,
+ int flags);
+
+#endif /* UTIL_LINUX_LOOPDEV_H */