libmount/src/mountP.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 /*
   3  * mountP.h - private library header file
   4  *
   5  * This file is part of libmount from util-linux project.
   6  *
   7  * Copyright (C) 2008-2018 Karel Zak <kzak@redhat.com>
   8  *
   9  * libmount is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  */
  14 #ifndef _LIBMOUNT_PRIVATE_H
  15 #define _LIBMOUNT_PRIVATE_H
  16
  17 #include <errno.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <sys/stat.h>
  21 #include <sys/types.h>
  22 #include <sys/vfs.h>
  23 #include <unistd.h>
  24 #include <stdio.h>
  25 #include <stdarg.h>
  26
  27 #include "c.h"
  28 #include "list.h"
  29 #include "debug.h"
  30 #include "libmount.h"
  31
  32 /*
  33  * Debug
  34  */
  35 #define MNT_DEBUG_HELP          (1 << 0)
  36 #define MNT_DEBUG_INIT          (1 << 1)
  37 #define MNT_DEBUG_CACHE         (1 << 2)
  38 #define MNT_DEBUG_OPTIONS       (1 << 3)
  39 #define MNT_DEBUG_LOCKS         (1 << 4)
  40 #define MNT_DEBUG_TAB           (1 << 5)
  41 #define MNT_DEBUG_FS            (1 << 6)
  42 #define MNT_DEBUG_UPDATE        (1 << 7)
  43 #define MNT_DEBUG_UTILS         (1 << 8)
  44 #define MNT_DEBUG_CXT           (1 << 9)
  45 #define MNT_DEBUG_DIFF          (1 << 10)
  46 #define MNT_DEBUG_MONITOR       (1 << 11)
  47 #define MNT_DEBUG_BTRFS         (1 << 12)
  48 #define MNT_DEBUG_LOOP          (1 << 13)
  49
  50 #define MNT_DEBUG_ALL           0xFFFF
  51
  52 UL_DEBUG_DECLARE_MASK(libmount);
  53 #define DBG(m, x)       __UL_DBG(libmount, MNT_DEBUG_, m, x)
  54 #define ON_DBG(m, x)    __UL_DBG_CALL(libmount, MNT_DEBUG_, m, x)
  55 #define DBG_FLUSH       __UL_DBG_FLUSH(libmount, MNT_DEBUG_)
  56
  57 #define UL_DEBUG_CURRENT_MASK   UL_DEBUG_MASK(libmount)
  58 #include "debugobj.h"
  59
  60 /*
  61  * NLS -- the library has to be independent on main program, so define
  62  * UL_TEXTDOMAIN_EXPLICIT before you include nls.h.
  63  *
  64  * Now we use util-linux.po (=PACKAGE), rather than maintain the texts
  65  * in the separate libmount.po file.
  66  */
  67 #define LIBMOUNT_TEXTDOMAIN     PACKAGE
  68 #define UL_TEXTDOMAIN_EXPLICIT  LIBMOUNT_TEXTDOMAIN
  69 #include "nls.h"
  70
  71
  72 /* extension for files in the directory */
  73 #define MNT_MNTTABDIR_EXT       ".fstab"
  74
  75 /* library private paths */
  76 #define MNT_RUNTIME_TOPDIR      "/run"
  77 #define MNT_RUNTIME_TOPDIR_OLD  "/dev"
  78
  79 #define MNT_PATH_UTAB           MNT_RUNTIME_TOPDIR "/mount/utab"
  80 #define MNT_PATH_UTAB_OLD       MNT_RUNTIME_TOPDIR_OLD "/.mount/utab"
  81
  82 #define MNT_UTAB_HEADER "# libmount utab file\n"
  83
  84 #ifdef TEST_PROGRAM
  85 struct libmnt_test {
  86         const char      *name;
  87         int             (*body)(struct libmnt_test *ts, int argc, char *argv[]);
  88         const char      *usage;
  89 };
  90
  91 /* test.c */
  92 extern int mnt_run_test(struct libmnt_test *tests, int argc, char *argv[]);
  93 #endif
  94
  95 /* utils.c */
  96 extern int mnt_valid_tagname(const char *tagname);
  97 extern int append_string(char **a, const char *b);
  98
  99 extern const char *mnt_statfs_get_fstype(struct statfs *vfs);
 100 extern int is_procfs_fd(int fd);
 101 extern int is_file_empty(const char *name);
 102
 103 extern int mnt_is_readonly(const char *path)
 104                         __attribute__((nonnull));
 105
 106 extern int mnt_parse_offset(const char *str, size_t len, uintmax_t *res);
 107
 108 extern int mnt_chdir_to_parent(const char *target, char **filename);
 109
 110 extern char *mnt_get_username(const uid_t uid);
 111 extern int mnt_get_uid(const char *username, uid_t *uid);
 112 extern int mnt_get_gid(const char *groupname, gid_t *gid);
 113 extern int mnt_in_group(gid_t gid);
 114
 115 extern int mnt_open_uniq_filename(const char *filename, char **name);
 116
 117 extern int mnt_has_regular_utab(const char **utab, int *writable);
 118 extern const char *mnt_get_utab_path(void);
 119
 120 extern int mnt_get_filesystems(char ***filesystems, const char *pattern);
 121 extern void mnt_free_filesystems(char **filesystems);
 122
 123 extern char *mnt_get_kernel_cmdline_option(const char *name);
 124 extern int mnt_stat_mountpoint(const char *target, struct stat *st);
 125 extern FILE *mnt_get_procfs_memstream(int fd, char **membuf);
 126
 127 /* tab.c */
 128 extern int is_mountinfo(struct libmnt_table *tb);
 129 extern int mnt_table_set_parser_fltrcb( struct libmnt_table *tb,
 130                                         int (*cb)(struct libmnt_fs *, void *),
 131                                         void *data);
 132
 133 extern int __mnt_table_parse_mtab(struct libmnt_table *tb,
 134                                         const char *filename,
 135                                         struct libmnt_table *u_tb);
 136
 137 extern struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
 138                                         struct libmnt_fs *fs,
 139                                         unsigned long mountflags,
 140                                         char **fsroot);
 141
 142 extern int __mnt_table_is_fs_mounted(   struct libmnt_table *tb,
 143                                         struct libmnt_fs *fstab_fs,
 144                                         const char *tgt_prefix);
 145
 146 /*
 147  * Generic iterator
 148  */
 149 struct libmnt_iter {
 150         struct list_head        *p;             /* current position */
 151         struct list_head        *head;          /* start position */
 152         int                     direction;      /* MNT_ITER_{FOR,BACK}WARD */
 153 };
 154
 155 #define IS_ITER_FORWARD(_i)     ((_i)->direction == MNT_ITER_FORWARD)
 156 #define IS_ITER_BACKWARD(_i)    ((_i)->direction == MNT_ITER_BACKWARD)
 157
 158 #define MNT_ITER_INIT(itr, list) \
 159         do { \
 160                 (itr)->p = IS_ITER_FORWARD(itr) ? \
 161                                 (list)->next : (list)->prev; \
 162                 (itr)->head = (list); \
 163         } while(0)
 164
 165 #define MNT_ITER_ITERATE(itr, res, restype, member) \
 166         do { \
 167                 res = list_entry((itr)->p, restype, member); \
 168                 (itr)->p = IS_ITER_FORWARD(itr) ? \
 169                                 (itr)->p->next : (itr)->p->prev; \
 170         } while(0)
 171
 172
 173 /*
 174  * This struct represents one entry in a mtab/fstab/mountinfo file.
 175  * (note that fstab[1] means the first column from fstab, and so on...)
 176  */
 177 struct libmnt_fs {
 178         struct list_head ents;
 179         struct libmnt_table *tab;
 180
 181         int             refcount;       /* reference counter */
 182         int             id;             /* mountinfo[1]: ID */
 183         int             parent;         /* mountinfo[2]: parent */
 184         dev_t           devno;          /* mountinfo[3]: st_dev */
 185
 186         char            *bindsrc;       /* utab, full path from fstab[1] for bind mounts */
 187
 188         char            *source;        /* fstab[1], mountinfo[10], swaps[1]:
 189                                          * source dev, file, dir or TAG */
 190         char            *tagname;       /* fstab[1]: tag name - "LABEL", "UUID", ..*/
 191         char            *tagval;        /*           tag value */
 192
 193         char            *root;          /* mountinfo[4]: root of the mount within the FS */
 194         char            *target;        /* mountinfo[5], fstab[2]: mountpoint */
 195         char            *fstype;        /* mountinfo[9], fstab[3]: filesystem type */
 196
 197         char            *optstr;        /* fstab[4], merged options */
 198         char            *vfs_optstr;    /* mountinfo[6]: fs-independent (VFS) options */
 199         char            *opt_fields;    /* mountinfo[7]: optional fields */
 200         char            *fs_optstr;     /* mountinfo[11]: fs-dependent options */
 201         char            *user_optstr;   /* userspace mount options */
 202         char            *attrs;         /* mount attributes */
 203
 204         int             freq;           /* fstab[5]: dump frequency in days */
 205         int             passno;         /* fstab[6]: pass number on parallel fsck */
 206
 207         /* /proc/swaps */
 208         char            *swaptype;      /* swaps[2]: device type (partition, file, ...) */
 209         off_t           size;           /* swaps[3]: swaparea size */
 210         off_t           usedsize;       /* swaps[4]: used size */
 211         int             priority;       /* swaps[5]: swap priority */
 212
 213         int             flags;          /* MNT_FS_* flags */
 214         pid_t           tid;            /* /proc/<tid>/mountinfo otherwise zero */
 215
 216         char            *comment;       /* fstab comment */
 217
 218         void            *userdata;      /* library independent data */
 219 };
 220
 221 /*
 222  * fs flags
 223  */
 224 #define MNT_FS_PSEUDO   (1 << 1) /* pseudo filesystem */
 225 #define MNT_FS_NET      (1 << 2) /* network filesystem */
 226 #define MNT_FS_SWAP     (1 << 3) /* swap device */
 227 #define MNT_FS_KERNEL   (1 << 4) /* data from /proc/{mounts,self/mountinfo} */
 228 #define MNT_FS_MERGED   (1 << 5) /* already merged data from /run/mount/utab */
 229
 230 #define mnt_fs_is_regular(_f)   (!(mnt_fs_is_pseudofs(_f) \
 231                                    || mnt_fs_is_netfs(_f) \
 232                                    || mnt_fs_is_swaparea(_f)))
 233
 234 /*
 235  * mtab/fstab/mountinfo file
 236  */
 237 struct libmnt_table {
 238         int             fmt;            /* MNT_FMT_* file format */
 239         int             nents;          /* number of entries */
 240         int             refcount;       /* reference counter */
 241         int             comms;          /* enable/disable comment parsing */
 242         char            *comm_intro;    /* First comment in file */
 243         char            *comm_tail;     /* Last comment in file */
 244
 245         struct libmnt_cache *cache;             /* canonicalized paths/tags cache */
 246
 247         int             (*errcb)(struct libmnt_table *tb,
 248                                  const char *filename, int line);
 249
 250         int             (*fltrcb)(struct libmnt_fs *fs, void *data);
 251         void            *fltrcb_data;
 252
 253
 254         struct list_head        ents;   /* list of entries (libmnt_fs) */
 255         void            *userdata;
 256 };
 257
 258 extern struct libmnt_table *__mnt_new_table_from_file(const char *filename, int fmt, int empty_for_enoent);
 259
 260 /*
 261  * Tab file format
 262  */
 263 enum {
 264         MNT_FMT_GUESS,
 265         MNT_FMT_FSTAB,                  /* /etc/{fs,m}tab */
 266         MNT_FMT_MTAB = MNT_FMT_FSTAB,   /* alias */
 267         MNT_FMT_MOUNTINFO,              /* /proc/#/mountinfo */
 268         MNT_FMT_UTAB,                   /* /run/mount/utab */
 269         MNT_FMT_SWAPS                   /* /proc/swaps */
 270 };
 271
 272 /*
 273  * Additional mounts
 274  */
 275 struct libmnt_addmount {
 276         unsigned long mountflags;
 277
 278         struct list_head        mounts;
 279 };
 280
 281 struct libmnt_ns {
 282         int fd;                         /* file descriptor of namespace, -1 when inactive */
 283         struct libmnt_cache *cache;     /* paths cache associated with NS */
 284 };
 285
 286 /*
 287  * Mount context -- high-level API
 288  */
 289 struct libmnt_context
 290 {
 291         int     action;         /* MNT_ACT_{MOUNT,UMOUNT} */
 292         int     restricted;     /* root or not? */
 293
 294         char    *fstype_pattern;        /* for mnt_match_fstype() */
 295         char    *optstr_pattern;        /* for mnt_match_options() */
 296
 297         struct libmnt_fs *fs;           /* filesystem description (type, mountpoint, device, ...) */
 298         struct libmnt_fs *fs_template;  /* used for @fs on mnt_reset_context() */
 299
 300         struct libmnt_table *fstab;     /* fstab (or mtab for some remounts) entries */
 301         struct libmnt_table *mtab;      /* mtab entries */
 302         struct libmnt_table *utab;      /* rarely used by umount only */
 303
 304         int     (*table_errcb)(struct libmnt_table *tb, /* callback for libmnt_table structs */
 305                          const char *filename, int line);
 306
 307         int     (*table_fltrcb)(struct libmnt_fs *fs, void *data);      /* callback for libmnt_table structs */
 308         void    *table_fltrcb_data;
 309
 310         char    *(*pwd_get_cb)(struct libmnt_context *);                /* get encryption password */
 311         void    (*pwd_release_cb)(struct libmnt_context *, char *);     /* release password */
 312
 313         int     optsmode;       /* fstab optstr mode MNT_OPTSMODE_{AUTO,FORCE,IGNORE} */
 314         int     loopdev_fd;     /* open loopdev */
 315
 316         unsigned long   mountflags;     /* final mount(2) flags */
 317         const void      *mountdata;     /* final mount(2) data, string or binary data */
 318
 319         unsigned long   user_mountflags;        /* MNT_MS_* (loop=, user=, ...) */
 320
 321         struct list_head        addmounts;      /* additional mounts */
 322
 323         struct libmnt_cache     *cache; /* paths cache */
 324         struct libmnt_lock      *lock;  /* mtab lock */
 325         struct libmnt_update    *update;/* mtab/utab update */
 326
 327         const char      *mtab_path; /* path to mtab */
 328         int             mtab_writable; /* is mtab writable */
 329
 330         const char      *utab_path; /* path to utab */
 331         int             utab_writable; /* is utab writable */
 332
 333         char            *tgt_prefix;    /* path used for all targets */
 334
 335         int     flags;          /* private context flags */
 336
 337         char    *helper;        /* name of the used /sbin/[u]mount.<type> helper */
 338         int     helper_status;  /* helper wait(2) status */
 339         int     helper_exec_status; /* 1: not called yet, 0: success, <0: -errno */
 340
 341         char    *orig_user;     /* original (non-fixed) user= option */
 342
 343         pid_t   *children;      /* "mount -a --fork" PIDs */
 344         int     nchildren;      /* number of children */
 345         pid_t   pid;            /* 0=parent; PID=child */
 346
 347
 348         int     syscall_status; /* 1: not called yet, 0: success, <0: -errno */
 349
 350         struct libmnt_ns        ns_orig;        /* original namespace */
 351         struct libmnt_ns        ns_tgt;         /* target namespace */
 352         struct libmnt_ns        *ns_cur;        /* pointer to current namespace */
 353
 354         unsigned int    enabled_textdomain : 1;         /* bindtextdomain() called */
 355 };
 356
 357 /* flags */
 358 #define MNT_FL_NOMTAB           (1 << 1)
 359 #define MNT_FL_FAKE             (1 << 2)
 360 #define MNT_FL_SLOPPY           (1 << 3)
 361 #define MNT_FL_VERBOSE          (1 << 4)
 362 #define MNT_FL_NOHELPERS        (1 << 5)
 363 #define MNT_FL_LOOPDEL          (1 << 6)
 364 #define MNT_FL_LAZY             (1 << 7)
 365 #define MNT_FL_FORCE            (1 << 8)
 366 #define MNT_FL_NOCANONICALIZE   (1 << 9)
 367 #define MNT_FL_RDONLY_UMOUNT    (1 << 11)       /* remount,ro after EBUSY umount(2) */
 368 #define MNT_FL_FORK             (1 << 12)
 369 #define MNT_FL_NOSWAPMATCH      (1 << 13)
 370 #define MNT_FL_RWONLY_MOUNT     (1 << 14)       /* explicit mount -w; never try read-only  */
 371
 372 #define MNT_FL_MOUNTDATA        (1 << 20)
 373 #define MNT_FL_TAB_APPLIED      (1 << 21)       /* mtab/fstab merged to cxt->fs */
 374 #define MNT_FL_MOUNTFLAGS_MERGED (1 << 22)      /* MS_* flags was read from optstr */
 375 #define MNT_FL_SAVED_USER       (1 << 23)
 376 #define MNT_FL_PREPARED         (1 << 24)
 377 #define MNT_FL_HELPER           (1 << 25)       /* [u]mount.<type> */
 378 #define MNT_FL_LOOPDEV_READY    (1 << 26)       /* /dev/loop<N> initialized by the library */
 379 #define MNT_FL_MOUNTOPTS_FIXED  (1 << 27)
 380 #define MNT_FL_TABPATHS_CHECKED (1 << 28)
 381 #define MNT_FL_FORCED_RDONLY    (1 << 29)       /* mounted read-only on write-protected device */
 382
 383 /* default flags */
 384 #define MNT_FL_DEFAULT          0
 385
 386 /* Flags usable with MS_BIND|MS_REMOUNT */
 387 #define MNT_BIND_SETTABLE       (MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_NOATIME|MS_NODIRATIME|MS_RELATIME|MS_RDONLY)
 388
 389 /* lock.c */
 390 extern int mnt_lock_use_simplelock(struct libmnt_lock *ml, int enable);
 391
 392 /* optmap.c */
 393 extern const struct libmnt_optmap *mnt_optmap_get_entry(
 394                              struct libmnt_optmap const **maps,
 395                              int nmaps,
 396                              const char *name,
 397                              size_t namelen,
 398                              const struct libmnt_optmap **mapent);
 399
 400 /* optstr.c */
 401 extern int mnt_optstr_remove_option_at(char **optstr, char *begin, char *end);
 402 extern int mnt_optstr_fix_gid(char **optstr, char *value, size_t valsz, char **next);
 403 extern int mnt_optstr_fix_uid(char **optstr, char *value, size_t valsz, char **next);
 404 extern int mnt_optstr_fix_secontext(char **optstr, char *value, size_t valsz, char **next);
 405 extern int mnt_optstr_fix_user(char **optstr);
 406
 407 /* fs.c */
 408 extern struct libmnt_fs *mnt_copy_mtab_fs(const struct libmnt_fs *fs)
 409                         __attribute__((nonnull));
 410 extern int __mnt_fs_set_source_ptr(struct libmnt_fs *fs, char *source)
 411                         __attribute__((nonnull(1)));
 412 extern int __mnt_fs_set_fstype_ptr(struct libmnt_fs *fs, char *fstype)
 413                         __attribute__((nonnull(1)));
 414
 415 /* context.c */
 416 extern struct libmnt_context *mnt_copy_context(struct libmnt_context *o);
 417 extern int mnt_context_mtab_writable(struct libmnt_context *cxt);
 418 extern int mnt_context_utab_writable(struct libmnt_context *cxt);
 419 extern const char *mnt_context_get_writable_tabpath(struct libmnt_context *cxt);
 420
 421 extern int mnt_context_get_mtab_for_target(struct libmnt_context *cxt,
 422                                     struct libmnt_table **mtab, const char *tgt);
 423
 424 extern int mnt_context_prepare_srcpath(struct libmnt_context *cxt);
 425 extern int mnt_context_prepare_target(struct libmnt_context *cxt);
 426 extern int mnt_context_guess_srcpath_fstype(struct libmnt_context *cxt, char **type);
 427 extern int mnt_context_guess_fstype(struct libmnt_context *cxt);
 428 extern int mnt_context_prepare_helper(struct libmnt_context *cxt,
 429                                       const char *name, const char *type);
 430 extern int mnt_context_prepare_update(struct libmnt_context *cxt);
 431 extern int mnt_context_merge_mflags(struct libmnt_context *cxt);
 432 extern int mnt_context_update_tabs(struct libmnt_context *cxt);
 433
 434 extern int mnt_context_umount_setopt(struct libmnt_context *cxt, int c, char *arg);
 435 extern int mnt_context_mount_setopt(struct libmnt_context *cxt, int c, char *arg);
 436
 437 extern int mnt_context_is_loopdev(struct libmnt_context *cxt)
 438                         __attribute__((nonnull));
 439
 440 extern int mnt_context_propagation_only(struct libmnt_context *cxt)
 441                         __attribute__((nonnull));
 442
 443 extern struct libmnt_addmount *mnt_new_addmount(void);
 444 extern void mnt_free_addmount(struct libmnt_addmount *ad);
 445
 446 extern int mnt_context_setup_loopdev(struct libmnt_context *cxt);
 447 extern int mnt_context_delete_loopdev(struct libmnt_context *cxt);
 448 extern int mnt_context_clear_loopdev(struct libmnt_context *cxt);
 449
 450 extern int mnt_fork_context(struct libmnt_context *cxt);
 451
 452 extern int mnt_context_set_tabfilter(struct libmnt_context *cxt,
 453                                      int (*fltr)(struct libmnt_fs *, void *),
 454                                      void *data);
 455
 456 extern int mnt_context_get_generic_excode(int rc, char *buf, size_t bufsz, char *fmt, ...);
 457 extern int mnt_context_get_mount_excode(struct libmnt_context *cxt, int mntrc, char *buf, size_t bufsz);
 458 extern int mnt_context_get_umount_excode(struct libmnt_context *cxt, int mntrc, char *buf, size_t bufsz);
 459
 460 extern int mnt_context_has_template(struct libmnt_context *cxt);
 461 extern int mnt_context_apply_template(struct libmnt_context *cxt);
 462 extern int mnt_context_save_template(struct libmnt_context *cxt);
 463
 464 extern int mnt_context_apply_fs(struct libmnt_context *cxt, struct libmnt_fs *fs);
 465
 466 /* tab_update.c */
 467 extern int mnt_update_set_filename(struct libmnt_update *upd,
 468                                    const char *filename, int userspace_only);
 469 extern int mnt_update_already_done(struct libmnt_update *upd,
 470                                    struct libmnt_lock *lc);
 471
 472 #if __linux__
 473 /* btrfs.c */
 474 extern uint64_t btrfs_get_default_subvol_id(const char *path);
 475 #endif
 476
 477 #endif /* _LIBMOUNT_PRIVATE_H */