struct libmnt_table

struct libmnt_table;

List of struct libmnt_fs entries (parsed fstab/mtab/mountinfo)

mnt_free_table ()

void                mnt_free_table                      (struct libmnt_table *tb);

Deallocates the table. This function does not care about reference count. Don't use this function directly -- it's better to use use mnt_unref_table().

The table entries (filesystems) are unrefrenced by mnt_reset_table() and cache by mnt_unref_cache().

mnt_new_table ()

struct libmnt_table * mnt_new_table                     (void);

The tab is a container for struct libmnt_fs entries that usually represents a fstab, mtab or mountinfo file from your system.

See also mnt_table_parse_file().

mnt_reset_table ()

int                 mnt_reset_table                     (struct libmnt_table *tb);

Removes all entries (filesystems) from the table. The filesystems with zero reference count will be deallocated.

mnt_ref_table ()

void                mnt_ref_table                       (struct libmnt_table *tb);

Increments reference counter.

mnt_unref_table ()

void                mnt_unref_table                     (struct libmnt_table *tb);

De-increments reference counter, on zero the tb is automatically deallocated by mnt_free_table().

mnt_new_table_from_dir ()

struct libmnt_table * mnt_new_table_from_dir            (const char *dirname);

mnt_new_table_from_file ()

struct libmnt_table * mnt_new_table_from_file           (const char *filename);

Same as mnt_new_table() + mnt_table_parse_file(). Use this function for private files only. This function does not allow using the error callback, so you cannot provide any feedback to end-users about broken records in files (e.g. fstab).

mnt_table_add_fs ()

int                 mnt_table_add_fs                    (struct libmnt_table *tb,
                                                         struct libmnt_fs *fs);

Adds a new entry to tab and increment fs reference counter. Don't forget to use mnt_unref_fs() after mnt_table_add_fs() you want to keep the fs referenced by the table only.

mnt_table_append_intro_comment ()

int                 mnt_table_append_intro_comment      (struct libmnt_table *tb,
                                                         const char *comm);

mnt_table_append_trailing_comment ()

int                 mnt_table_append_trailing_comment   (struct libmnt_table *tb,
                                                         const char *comm);

Appends to the trailing table comment.

mnt_table_enable_comments ()

void                mnt_table_enable_comments           (struct libmnt_table *tb,
                                                         int enable);

Enables parsing of comments.

The initial (intro) file comment is accessible by mnt_table_get_intro_comment(). The intro and the comment of the first fstab entry has to be separated by blank line. The filesystem comments are accessible by mnt_fs_get_comment(). The trailing fstab comment is accessible by mnt_table_get_trailing_comment().

1
2
3
4
5
6
7
8
9

#
# Intro comment
#

# this comments belongs to the first fs
LABEL=foo /mnt/foo auto defaults 1 2
# this comments belongs to the second fs
LABEL=bar /mnt/bar auto defaults 1 2 
# tailing comment

mnt_table_find_devno ()

struct libmnt_fs *  mnt_table_find_devno                (struct libmnt_table *tb,
                                                         dev_t devno,
                                                         int direction);

Note that zero could be a valid device number for the root pseudo filesystem (e.g. tmpfs).

mnt_table_find_mountpoint ()

struct libmnt_fs *  mnt_table_find_mountpoint           (struct libmnt_table *tb,
                                                         const char *path,
                                                         int direction);

Same as mnt_get_mountpoint(), except this function does not rely on st_dev numbers.

mnt_table_find_next_fs ()

int                 mnt_table_find_next_fs              (struct libmnt_table *tb,
                                                         struct libmnt_iter *itr,
                                                         int (*match_func) (struct libmnt_fs *, void *),
                                                         void *userdata,
                                                         struct libmnt_fs **fs);

This function allows searching in tb.

mnt_table_find_pair ()

struct libmnt_fs *  mnt_table_find_pair                 (struct libmnt_table *tb,
                                                         const char *source,
                                                         const char *target,
                                                         int direction);

This function is implemented by mnt_fs_match_source() and mnt_fs_match_target() functions. It means that this is more expensive than others mnt_table_find_* function, because every tab entry is fully evaluated.

mnt_table_find_source ()

struct libmnt_fs *  mnt_table_find_source               (struct libmnt_table *tb,
                                                         const char *source,
                                                         int direction);

This is a high-level API for mnt_table_find_{srcpath,tag}. You needn't care about the source format (device, LABEL, UUID, ...). This function parses the source and calls mnt_table_find_tag() or mnt_table_find_srcpath().

mnt_table_find_srcpath ()

struct libmnt_fs *  mnt_table_find_srcpath              (struct libmnt_table *tb,
                                                         const char *path,
                                                         int direction);

Try to lookup an entry in the given tab, four iterations are possible, the first with path, the second with realpath(path), the third with tags (LABEL, UUID, ..) from path and the fourth with realpath(path) against realpath(entry->srcpath).

The 2nd, 3rd and 4th iterations are not performed when the tb cache is not set (see mnt_table_set_cache()).

Note that NULL is a valid source path; it will be replaced with "none". The "none" is used in /proc/{mounts,self/mountinfo} for pseudo filesystems.

mnt_table_find_tag ()

struct libmnt_fs *  mnt_table_find_tag                  (struct libmnt_table *tb,
                                                         const char *tag,
                                                         const char *val,
                                                         int direction);

Try to lookup an entry in the given tab, the first attempt is to lookup by tag and val, for the second attempt the tag is evaluated (converted to the device name) and mnt_table_find_srcpath() is performed. The second attempt is not performed when tb cache is not set (see mnt_table_set_cache()).

mnt_table_find_target ()

struct libmnt_fs *  mnt_table_find_target               (struct libmnt_table *tb,
                                                         const char *path,
                                                         int direction);

Try to lookup an entry in the given tab, three iterations are possible, the first with path, the second with realpath(path) and the third with realpath(path) against realpath(fs->target). The 2nd and 3rd iterations are not performed when the tb cache is not set (see mnt_table_set_cache()). If mnt_cache_set_targets(cache, mtab) was called, the 3rd iteration skips any fs->target found in mtab (see mnt_resolve_target()).

mnt_table_first_fs ()

int                 mnt_table_first_fs                  (struct libmnt_table *tb,
                                                         struct libmnt_fs **fs);

mnt_table_get_cache ()

struct libmnt_cache * mnt_table_get_cache               (struct libmnt_table *tb);

mnt_table_get_intro_comment ()

const char *        mnt_table_get_intro_comment         (struct libmnt_table *tb);

mnt_table_get_nents ()

int                 mnt_table_get_nents                 (struct libmnt_table *tb);

mnt_table_get_root_fs ()

int                 mnt_table_get_root_fs               (struct libmnt_table *tb,
                                                         struct libmnt_fs **root);

The function uses the parent ID from the mountinfo file to determine the root filesystem (the filesystem with the smallest ID). The function is designed mostly for applications where it is necessary to sort mountpoints by IDs to get the tree of the mountpoints (e.g. findmnt default output).

If you're not sure, then use

mnt_table_find_target(tb, "/", MNT_ITER_BACKWARD);

this is more robust and usable for arbitrary tab files (including fstab).

mnt_table_get_trailing_comment ()

const char *        mnt_table_get_trailing_comment      (struct libmnt_table *tb);

mnt_table_get_userdata ()

void *              mnt_table_get_userdata              (struct libmnt_table *tb);

mnt_table_is_empty ()

int                 mnt_table_is_empty                  (struct libmnt_table *tb);

mnt_table_is_fs_mounted ()

int                 mnt_table_is_fs_mounted             (struct libmnt_table *tb,
                                                         struct libmnt_fs *fstab_fs);

mnt_table_last_fs ()

int                 mnt_table_last_fs                   (struct libmnt_table *tb,
                                                         struct libmnt_fs **fs);

mnt_table_next_child_fs ()

int                 mnt_table_next_child_fs             (struct libmnt_table *tb,
                                                         struct libmnt_iter *itr,
                                                         struct libmnt_fs *parent,
                                                         struct libmnt_fs **chld);

Note that filesystems are returned in the order of mounting (according to IDs in /proc/self/mountinfo).

mnt_table_next_fs ()

int                 mnt_table_next_fs                   (struct libmnt_table *tb,
                                                         struct libmnt_iter *itr,
                                                         struct libmnt_fs **fs);

1
2
3
4

while(mnt_table_next_fs(tb, itr, &fs) == 0) {
const char *dir = mnt_fs_get_target(fs);
printf("mount point: %s\n", dir);
}

mnt_table_parse_dir ()

int                 mnt_table_parse_dir                 (struct libmnt_table *tb,
                                                         const char *dirname);

The directory:

mnt_table_parse_file ()

int                 mnt_table_parse_file                (struct libmnt_table *tb,
                                                         const char *filename);

Parses the whole table (e.g. /etc/mtab) and appends new records to the tab.

The libmount parser ignores broken (syntax error) lines, these lines are reported to the caller by the errcb() function (see mnt_table_set_parser_errcb()).

mnt_table_parse_fstab ()

int                 mnt_table_parse_fstab               (struct libmnt_table *tb,
                                                         const char *filename);

This function parses /etc/fstab and appends new lines to the tab. If the filename is a directory, then mnt_table_parse_dir() is called.

See also mnt_table_set_parser_errcb().

mnt_table_parse_mtab ()

int                 mnt_table_parse_mtab                (struct libmnt_table *tb,
                                                         const char *filename);

This function parses /etc/mtab or /proc/self/mountinfo + /run/mount/utabs or /proc/mounts.

See also mnt_table_set_parser_errcb().

mnt_table_parse_stream ()

int                 mnt_table_parse_stream              (struct libmnt_table *tb,
                                                         FILE *f,
                                                         const char *filename);

mnt_table_parse_swaps ()

int                 mnt_table_parse_swaps               (struct libmnt_table *tb,
                                                         const char *filename);

This function parses /proc/swaps and appends new lines to the tab.

See also mnt_table_set_parser_errcb().

mnt_table_remove_fs ()

int                 mnt_table_remove_fs                 (struct libmnt_table *tb,
                                                         struct libmnt_fs *fs);

Removes the fs from the table and de-increment reference counter of the fs. The filesystem with zero reference counter will be deallocated. Don't forget to use mnt_ref_fs() before call mnt_table_remove_fs() if you want to use fs later.

mnt_table_set_cache ()

int                 mnt_table_set_cache                 (struct libmnt_table *tb,
                                                         struct libmnt_cache *mpc);

Sets up a cache for canonicalized paths and evaluated tags (LABEL/UUID). The cache is recommended for mnt_table_find_*() functions.

The cache could be shared between more tabs. Be careful when you share the same cache between more threads -- currently the cache does not provide any locking method.

This function increments cache reference counter. It's recomented to use mnt_unref_cache() after mnt_table_set_cache() if you want to keep the cache referenced by tb only.

See also mnt_new_cache().

mnt_table_set_intro_comment ()

int                 mnt_table_set_intro_comment         (struct libmnt_table *tb,
                                                         const char *comm);

mnt_table_set_iter ()

int                 mnt_table_set_iter                  (struct libmnt_table *tb,
                                                         struct libmnt_iter *itr,
                                                         struct libmnt_fs *fs);

Sets iter to the position of fs in the file tb.

mnt_table_set_parser_errcb ()

int                 mnt_table_set_parser_errcb          (struct libmnt_table *tb,
                                                         int (*cb) (struct libmnt_table *tb, const char *filename, int line));

The error callback function is called by table parser (mnt_table_parse_file()) in case of a syntax error. The callback function could be used for error evaluation, libmount will continue/stop parsing according to callback return codes:

<0 : fatal error (abort parsing) 0 : success (parsing continues) >0 : recoverable error (the line is ignored, parsing continues).

mnt_table_set_trailing_comment ()

int                 mnt_table_set_trailing_comment      (struct libmnt_table *tb,
                                                         const char *comm);

Sets the trailing comment in table.

mnt_table_set_userdata ()

int                 mnt_table_set_userdata              (struct libmnt_table *tb,
                                                         void *data);

Sets pointer to the private user data.

mnt_table_with_comments ()

int                 mnt_table_with_comments             (struct libmnt_table *tb);

mnt_table_uniq_fs ()

int                 mnt_table_uniq_fs                   (struct libmnt_table *tb,
                                                         int flags,
                                                         int (*cmp) (struct libmnt_table *, struct libmnt_fs *, struct libmnt_fs *));

This function de-duplicate the tb, but does not change order of the filesystems. The cmp function has to return 0 if the filesystems are equal, otherwise non-zero.

The default is to keep in the table later mounted filesystems (function uses backward mode iterator).

MNT_UNIQ_FORWARD: remove later mounted filesystems MNT_UNIQ_KEEPTREE: keep parent->id relation ship stil valid