mnt_free_context ()

void
mnt_free_context (struct libmnt_context *cxt);

Deallocates context struct.

mnt_new_context ()

struct libmnt_context *
mnt_new_context (void);

mnt_reset_context ()

int
mnt_reset_context (struct libmnt_context *cxt);

Resets all information in the context that is directly related to the latest mount (spec, source, target, mount options, ...).

The match patterns, target namespace, prefix, cached fstab, cached canonicalized paths and tags and [e]uid are not reset. You have to use

mnt_context_set_fstab(cxt, NULL); mnt_context_set_cache(cxt, NULL); mnt_context_set_fstype_pattern(cxt, NULL); mnt_context_set_options_pattern(cxt, NULL); mnt_context_set_target_ns(cxt, NULL);

to reset this stuff.

mnt_context_append_options ()

int
mnt_context_append_options (struct libmnt_context *cxt,
                            const char *optstr);

mnt_context_apply_fstab ()

int
mnt_context_apply_fstab (struct libmnt_context *cxt);

This function is optional.

mnt_context_disable_canonicalize ()

int
mnt_context_disable_canonicalize (struct libmnt_context *cxt,
                                  int disable);

Enable/disable paths canonicalization and tags evaluation. The libmount context canonicalizes paths when searching in fstab and when preparing source and target paths for mount(2) syscall.

This function has an effect on the private (within context) fstab instance only (see mnt_context_set_fstab()). If you want to use an external fstab then you need to manage your private struct libmnt_cache (see mnt_table_set_cache(fstab, NULL).

mnt_context_disable_helpers ()

int
mnt_context_disable_helpers (struct libmnt_context *cxt,
                             int disable);

Enable/disable /sbin/[u]mount.* helpers (see mount(8) man page, option -i).

mnt_context_disable_mtab ()

int
mnt_context_disable_mtab (struct libmnt_context *cxt,
                          int disable);

Disable/enable mtab update (see mount(8) man page, option -n).

mnt_context_disable_swapmatch ()

int
mnt_context_disable_swapmatch (struct libmnt_context *cxt,
                               int disable);

Disable/enable swap between source and target for mount(8) if only one path is specified.

mnt_context_enable_fake ()

int
mnt_context_enable_fake (struct libmnt_context *cxt,
                         int enable);

Enable/disable fake mounting (see mount(8) man page, option -f).

mnt_context_enable_force ()

int
mnt_context_enable_force (struct libmnt_context *cxt,
                          int enable);

Enable/disable force umounting (see umount(8) man page, option -f).

mnt_context_enable_fork ()

int
mnt_context_enable_fork (struct libmnt_context *cxt,
                         int enable);

Enable/disable fork(2) call in mnt_context_next_mount() (see mount(8) man page, option -F).

mnt_context_enable_lazy ()

int
mnt_context_enable_lazy (struct libmnt_context *cxt,
                         int enable);

Enable/disable lazy umount (see umount(8) man page, option -l).

mnt_context_enable_loopdel ()

int
mnt_context_enable_loopdel (struct libmnt_context *cxt,
                            int enable);

Enable/disable the loop delete (destroy) after umount (see umount(8), option -d)

mnt_context_enable_rdonly_umount ()

int
mnt_context_enable_rdonly_umount (struct libmnt_context *cxt,
                                  int enable);

Enable/disable read-only remount on failed umount(2) (see umount(8) man page, option -r).

mnt_context_enable_rwonly_mount ()

int
mnt_context_enable_rwonly_mount (struct libmnt_context *cxt,
                                 int enable);

Force read-write mount; if enabled libmount will never try MS_RDONLY after failed mount(2) EROFS. (See mount(8) man page, option -w).

Since: 2.30

mnt_context_enable_sloppy ()

int
mnt_context_enable_sloppy (struct libmnt_context *cxt,
                           int enable);

Set/unset sloppy mounting (see mount(8) man page, option -s).

mnt_context_enable_verbose ()

int
mnt_context_enable_verbose (struct libmnt_context *cxt,
                            int enable);

Enable/disable verbose output (TODO: not implemented yet)

mnt_context_forced_rdonly ()

int
mnt_context_forced_rdonly (struct libmnt_context *cxt);

See also mnt_context_enable_rwonly_mount().

Since: 2.30

mnt_context_force_unrestricted ()

int
mnt_context_force_unrestricted (struct libmnt_context *cxt);

This function is DANGEROURS as it disables all security policies in libmount. Don't use if not sure. It removes "restricted" flag from the context, so libmount will use the current context as for root user.

This function is designed for case you have no any suid permissions, so you can depend on kernel.

Since: 2.35

mnt_context_get_cache ()

struct libmnt_cache *
mnt_context_get_cache (struct libmnt_context *cxt);

See also mnt_context_set_cache().

mnt_context_get_excode ()

int
mnt_context_get_excode (struct libmnt_context *cxt,
                        int rc,
                        char *buf,
                        size_t bufsz);

This function analyzes context, [u]mount syscall and external helper status and mntrc and generates unified return code (see MNT_EX_*) as expected from mount(8) or umount(8).

If the external helper (e.g. /sbin/mount.type) has been executed than it returns status from wait() of the helper. It's not libmount fail if helper returns some crazy undocumented codes... See mnt_context_helper_executed() and mnt_context_get_helper_status(). Note that mount(8) and umount(8) utils always return code from helper without extra care about it.

If the argument buf is not NULL then error message is generated (if anything failed).

The mntrc is usually return code from mnt_context_mount(), mnt_context_umount(), or 'mntrc' as returned by mnt_context_next_mount().

Since: 2.30

mnt_context_get_fs ()

struct libmnt_fs *
mnt_context_get_fs (struct libmnt_context *cxt);

The FS contains the basic description of mountpoint, fs type and so on. Note that the FS is modified by mnt_context_set_{source,target,options,fstype} functions.

mnt_context_get_fstab ()

int
mnt_context_get_fstab (struct libmnt_context *cxt,
                       struct libmnt_table **tb);

See also mnt_table_parse_fstab() for more details about fstab.

mnt_context_get_fstab_userdata ()

void *
mnt_context_get_fstab_userdata (struct libmnt_context *cxt);

mnt_context_get_fstype ()

const char *
mnt_context_get_fstype (struct libmnt_context *cxt);

mnt_context_get_fs_userdata ()

void *
mnt_context_get_fs_userdata (struct libmnt_context *cxt);

mnt_context_get_helper_status ()

int
mnt_context_get_helper_status (struct libmnt_context *cxt);

Return: mount.type helper exit status, result is reliable only if mnt_context_helper_executed() returns 1.

mnt_context_get_lock ()

struct libmnt_lock *
mnt_context_get_lock (struct libmnt_context *cxt);

The libmount applications don't have to care about mtab locking, but with a small exception: the application has to be able to remove the lock file when interrupted by signal or signals have to be ignored when the lock is locked.

The default behavior is to ignore all signals (except SIGALRM and SIGTRAP for mtab update) when the lock is locked. If this behavior is unacceptable, then use:

lc = mnt_context_get_lock(cxt); if (lc) mnt_lock_block_signals(lc, FALSE);

and don't forget to call mnt_unlock_file(lc) before exit.

mnt_context_get_mflags ()

int
mnt_context_get_mflags (struct libmnt_context *cxt,
                        unsigned long *flags);

Converts mount options string to MS_* flags and bitwise-OR the result with the already defined flags (see mnt_context_set_mflags()).

mnt_context_get_mtab ()

int
mnt_context_get_mtab (struct libmnt_context *cxt,
                      struct libmnt_table **tb);

See also mnt_table_parse_mtab() for more details about mtab/mountinfo. The result will be deallocated by mnt_free_context(cxt ).

mnt_context_get_mtab_userdata ()

void *
mnt_context_get_mtab_userdata (struct libmnt_context *cxt);

mnt_context_get_options ()

const char *
mnt_context_get_options (struct libmnt_context *cxt);

This function returns mount options set by mnt_context_set_options() or mnt_context_append_options().

Note that *after* mnt_context_prepare_mount(), the mount options string may also include options set by mnt_context_set_mflags() or other options generated by this library.

mnt_context_get_optsmode ()

int
mnt_context_get_optsmode (struct libmnt_context *cxt);

mnt_context_get_origin_ns ()

struct libmnt_ns *
mnt_context_get_origin_ns (struct libmnt_context *cxt);

Since: 2.33

mnt_context_get_source ()

const char *
mnt_context_get_source (struct libmnt_context *cxt);

mnt_context_get_status ()

int
mnt_context_get_status (struct libmnt_context *cxt);

Global libmount status.

The real exit code of the mount.type helper has to be tested by mnt_context_get_helper_status(). The mnt_context_get_status() only informs that exec() has been successful.

mnt_context_get_syscall_errno ()

int
mnt_context_get_syscall_errno (struct libmnt_context *cxt);

The result from this function is reliable only if mnt_context_syscall_called() returns 1.

mnt_context_get_table ()

int
mnt_context_get_table (struct libmnt_context *cxt,
                       const char *filename,
                       struct libmnt_table **tb);

This function allocates a new table and parses the file . The parser error callback and cache for tags and paths is set according to the cxt setting. See also mnt_table_parse_file().

It's strongly recommended to use the mnt_context_get_mtab() and mnt_context_get_fstab() functions for mtab and fstab files. This function does not care about LIBMOUNT_* env.variables and does not merge userspace options.

The result will NOT be deallocated by mnt_free_context(cxt ).

mnt_context_get_target ()

const char *
mnt_context_get_target (struct libmnt_context *cxt);

mnt_context_get_target_ns ()

struct libmnt_ns *
mnt_context_get_target_ns (struct libmnt_context *cxt);

Since: 2.33

mnt_context_get_target_prefix ()

const char *
mnt_context_get_target_prefix (struct libmnt_context *cxt);

mnt_context_get_user_mflags ()

int
mnt_context_get_user_mflags (struct libmnt_context *cxt,
                             unsigned long *flags);

Converts mount options string to MNT_MS_* flags and bitwise-OR the result with the already defined flags (see mnt_context_set_user_mflags()).

mnt_context_helper_executed ()

int
mnt_context_helper_executed (struct libmnt_context *cxt);

mnt_context_helper_setopt ()

int
mnt_context_helper_setopt (struct libmnt_context *cxt,
                           int c,
                           char *arg);

This function applies the [u]mount.type command line option (for example parsed by getopt or getopt_long) to cxt . All unknown options are ignored and then 1 is returned.

mnt_context_init_helper ()

int
mnt_context_init_helper (struct libmnt_context *cxt,
                         int action,
                         int flags);

This function informs libmount that used from [u]mount.type helper.

The function also calls mnt_context_disable_helpers() to avoid recursive mount.type helpers calling. It you really want to call another mount.type helper from your helper, then you have to explicitly enable this feature by:

mnt_context_disable_helpers(cxt, FALSE);

mnt_context_is_child ()

int
mnt_context_is_child (struct libmnt_context *cxt);

Return: 1 f the current context is child, or 0

mnt_context_is_fake ()

int
mnt_context_is_fake (struct libmnt_context *cxt);

mnt_context_is_force ()

int
mnt_context_is_force (struct libmnt_context *cxt);

mnt_context_is_fork ()

int
mnt_context_is_fork (struct libmnt_context *cxt);

mnt_context_is_fs_mounted ()

int
mnt_context_is_fs_mounted (struct libmnt_context *cxt,
                           struct libmnt_fs *fs,
                           int *mounted);

Please, read the mnt_table_is_fs_mounted() description!

mnt_context_is_lazy ()

int
mnt_context_is_lazy (struct libmnt_context *cxt);

mnt_context_is_loopdel ()

int
mnt_context_is_loopdel (struct libmnt_context *cxt);

mnt_context_is_nocanonicalize ()

int
mnt_context_is_nocanonicalize (struct libmnt_context *cxt);

mnt_context_is_nohelpers ()

int
mnt_context_is_nohelpers (struct libmnt_context *cxt);

mnt_context_is_nomtab ()

int
mnt_context_is_nomtab (struct libmnt_context *cxt);

mnt_context_is_parent ()

int
mnt_context_is_parent (struct libmnt_context *cxt);

Return: 1 if mount -F enabled and the current context is parent, or 0

mnt_context_is_rdonly_umount ()

int
mnt_context_is_rdonly_umount (struct libmnt_context *cxt);

See also mnt_context_enable_rdonly_umount() and umount(8) man page, option -r.

mnt_context_is_restricted ()

int
mnt_context_is_restricted (struct libmnt_context *cxt);

mnt_context_is_rwonly_mount ()

int
mnt_context_is_rwonly_mount (struct libmnt_context *cxt);

See also mnt_context_enable_rwonly_mount() and mount(8) man page, option -w.

Since: 2.30

mnt_context_is_sloppy ()

int
mnt_context_is_sloppy (struct libmnt_context *cxt);

mnt_context_is_swapmatch ()

int
mnt_context_is_swapmatch (struct libmnt_context *cxt);

mnt_context_is_verbose ()

int
mnt_context_is_verbose (struct libmnt_context *cxt);

mnt_context_reset_status ()

int
mnt_context_reset_status (struct libmnt_context *cxt);

Resets mount(2) and mount.type statuses, so mnt_context_do_mount() or mnt_context_do_umount() could be again called with the same settings.

BE CAREFUL -- after this soft reset the libmount will NOT parse mount options, evaluate permissions or apply stuff from fstab.

mnt_context_set_cache ()

int
mnt_context_set_cache (struct libmnt_context *cxt,
                       struct libmnt_cache *cache);

The mount context maintains a private struct libmnt_cache by default. This function can be used to overwrite the private cache with an external instance. This function increments cache reference counter.

If the cache argument is NULL, then the current cache instance is reset. This function apply the cache to fstab and mtab instances (if already exists).

The old cache instance reference counter is de-incremented.

mnt_context_set_fs ()

int
mnt_context_set_fs (struct libmnt_context *cxt,
                    struct libmnt_fs *fs);

The mount context uses private fs by default. This function can be used to overwrite the private fs with an external instance. This function increments fs reference counter (and decrement reference counter of the old fs).

The fs will be modified by mnt_context_set_{source,target,options,fstype} functions, If the fs is NULL, then all current FS specific settings (source, target, etc., exclude spec) are reset.

mnt_context_set_fstab ()

int
mnt_context_set_fstab (struct libmnt_context *cxt,
                       struct libmnt_table *tb);

The mount context reads /etc/fstab to the private struct libmnt_table by default. This function can be used to overwrite the private fstab with an external instance.

This function modify the tb reference counter. This function does not set the cache for the tb . You have to explicitly call mnt_table_set_cache(tb, mnt_context_get_cache(cxt));

The fstab is used read-only and is not modified, it should be possible to share the fstab between more mount contexts (TODO: test it.)

If the tb argument is NULL, then the current private fstab instance is reset.

mnt_context_set_fstype ()

int
mnt_context_set_fstype (struct libmnt_context *cxt,
                        const char *fstype);

Note that the fstype has to be a FS type. For patterns with comma-separated list of filesystems or for the "nofs" notation, use mnt_context_set_fstype_pattern().

mnt_context_set_fstype_pattern ()

int
mnt_context_set_fstype_pattern (struct libmnt_context *cxt,
                                const char *pattern);

See mount(8), option -t.

mnt_context_set_mflags ()

int
mnt_context_set_mflags (struct libmnt_context *cxt,
                        unsigned long  flags);

Sets mount flags (see mount(2) man page).

Note that mount context can be used to define mount options by mount flags. It means you can for example use

mnt_context_set_mflags(cxt, MS_NOEXEC | MS_NOSUID);

rather than

mnt_context_set_options(cxt, "noexec,nosuid");

both of these calls have the same effect.

Be careful if you want to use MS_REC flag -- in this case the bit is applied to all bind/slave/etc. options. If you want to mix more propadation flags and/or bind operations than it's better to specify mount options by strings.

mnt_context_set_mountdata ()

int
mnt_context_set_mountdata (struct libmnt_context *cxt,
                           void *data);

The mount context generates mountdata from mount options by default. This function can be used to overwrite this behavior, and data will be used instead of mount options.

The libmount does not deallocate the data by mnt_free_context(). Note that NULL is also valid mount data.

mnt_context_set_options ()

int
mnt_context_set_options (struct libmnt_context *cxt,
                         const char *optstr);

Note that MS_MOVE cannot be specified as "string". It's operation that is no supported in fstab (etc.)

mnt_context_set_options_pattern ()

int
mnt_context_set_options_pattern (struct libmnt_context *cxt,
                                 const char *pattern);

See mount(8), option -O.

mnt_context_set_optsmode ()

int
mnt_context_set_optsmode (struct libmnt_context *cxt,
                          int mode);

Controls how to use mount optionssource and target paths from fstab/mtab.

MNT_OMODE_IGNORE : ignore mtab/fstab options

MNT_OMODE_APPEND : append mtab/fstab options to existing options

MNT_OMODE_PREPEND : prepend mtab/fstab options to existing options

MNT_OMODE_REPLACE : replace existing options with options from mtab/fstab

MNT_OMODE_FORCE : always read mtab/fstab (although source and target are defined)

MNT_OMODE_FSTAB : read from fstab

MNT_OMODE_MTAB : read from mtab if fstab not enabled or failed

MNT_OMODE_NOTAB : do not read fstab/mtab at all

MNT_OMODE_AUTO : default mode (MNT_OMODE_PREPEND | MNT_OMODE_FSTAB | MNT_OMODE_MTAB)

MNT_OMODE_USER : default for non-root users (MNT_OMODE_REPLACE | MNT_OMODE_FORCE | MNT_OMODE_FSTAB)

Notes:

mnt_context_set_passwd_cb ()

int
mnt_context_set_passwd_cb (struct libmnt_context *cxt,
                           char* (*get) (struct libmnt_context *),
                           void (*release) (struct libmnt_context *, char *));

Sets callbacks for encryption password (e.g encrypted loopdev). This function is deprecated (encrypted loops are no longer supported).

mnt_context_set_source ()

int
mnt_context_set_source (struct libmnt_context *cxt,
                        const char *source);

Note that libmount does not interpret "nofail" (MNT_MS_NOFAIL) mount option. The real return code is always returned, when the device does not exist then it's usually MNT_ERR_NOSOURCE from libmount or ENOENT, ENOTDIR, ENOTBLK, ENXIO from mount(2).

mnt_context_set_syscall_status ()

int
mnt_context_set_syscall_status (struct libmnt_context *cxt,
                                int status);

The status should be 0 on success, or negative number on error (-errno).

This function should only be used if the [u]mount(2) syscall is NOT called by libmount code.

mnt_context_set_tables_errcb ()

int
mnt_context_set_tables_errcb (struct libmnt_context *cxt,
                              int (*cb) (struct libmnt_table *tb, const char *filename, int line));

The error callback is used for all tab files (e.g. mtab, fstab) parsed within the context.

See also mnt_context_get_mtab(), mnt_context_get_fstab(), mnt_table_set_parser_errcb().

mnt_context_set_target ()

int
mnt_context_set_target (struct libmnt_context *cxt,
                        const char *target);

mnt_context_set_target_ns ()

int
mnt_context_set_target_ns (struct libmnt_context *cxt,
                           const char *path);

Sets target namespace to namespace represented by path . If path is NULL, target namespace is cleared.

This function sets errno to ENOSYS and returns error if libmount is compiled without namespaces support.

Since: 2.33

mnt_context_set_target_prefix ()

int
mnt_context_set_target_prefix (struct libmnt_context *cxt,
                               const char *path);

mnt_context_set_user_mflags ()

int
mnt_context_set_user_mflags (struct libmnt_context *cxt,
                             unsigned long  flags);

Sets userspace mount flags.

See also notes for mnt_context_set_mflags().

mnt_context_strerror ()

int
mnt_context_strerror (struct libmnt_context *cxt,
                      char *buf,
                      size_t bufsiz);

Not implemented, deprecated in favor or mnt_context_get_excode().

mnt_context_switch_ns ()

struct libmnt_ns *
mnt_context_switch_ns (struct libmnt_context *cxt,
                       struct libmnt_ns *ns);

Switch to namespace specified by ns

Typical usage:

1
2
3
4

struct libmnt_ns *ns_old;
ns_old = mnt_context_switch_ns(cxt, mnt_context_get_target_ns(cxt));
... code ...
mnt_context_switch_ns(cxt, ns_old);

Since: 2.33

mnt_context_switch_origin_ns ()

struct libmnt_ns *
mnt_context_switch_origin_ns (struct libmnt_context *cxt);

Switch to original namespace

This is shorthand for

1

mnt_context_switch_ns(cxt, mnt_context_get_origin_ns(cxt));

Since: 2.33

mnt_context_switch_target_ns ()

struct libmnt_ns *
mnt_context_switch_target_ns (struct libmnt_context *cxt);

Switch to target namespace

This is shorthand for

1

mnt_context_switch_ns(cxt, mnt_context_get_target_ns(cxt));

Since: 2.33

mnt_context_syscall_called ()

int
mnt_context_syscall_called (struct libmnt_context *cxt);

mnt_context_tab_applied ()

int
mnt_context_tab_applied (struct libmnt_context *cxt);

mnt_context_wait_for_children ()

int
mnt_context_wait_for_children (struct libmnt_context *cxt,
                               int *nchildren,
                               int *nerrs);

struct libmnt_context

struct libmnt_context;

Mount/umount status

struct libmnt_ns

struct libmnt_ns;

Describes mount namespace

MNT_ERR_AMBIFS

#define MNT_ERR_AMBIFS       5006

libblkid detected more filesystems on the device

MNT_ERR_APPLYFLAGS

#define MNT_ERR_APPLYFLAGS   5005

failed to apply MS_PROPAGATION flags

MNT_ERR_LOOPDEV

#define MNT_ERR_LOOPDEV      5003

loopdev setup failed, errno set by libc

MNT_ERR_MOUNTOPT

#define MNT_ERR_MOUNTOPT     5004

failed to parse/use userspace mount options

MNT_ERR_NOFSTAB

#define MNT_ERR_NOFSTAB      5000

not found required entry in fstab

MNT_ERR_NOFSTYPE

#define MNT_ERR_NOFSTYPE     5001

failed to detect filesystem type

MNT_ERR_NOSOURCE

#define MNT_ERR_NOSOURCE     5002

required mount source undefined

MNT_ERR_LOOPOVERLAP

#define MNT_ERR_LOOPOVERLAP 5007

detected overlapping loop device that cannot be re-used

MNT_ERR_LOCK

#define MNT_ERR_LOCK         5008

failed to lock mtab/utab or so.

MNT_ERR_NAMESPACE

#define MNT_ERR_NAMESPACE    5009

failed to switch namespace

MNT_EX_SUCCESS

#define MNT_EX_SUCCESS 0

[u]mount(8) exit code: no errors

MNT_EX_USAGE

#define MNT_EX_USAGE 1

[u]mount(8) exit code: incorrect invocation or permission

MNT_EX_SYSERR

#define MNT_EX_SYSERR 2

[u]mount(8) exit code: out of memory, cannot fork, ...

MNT_EX_SOFTWARE

#define MNT_EX_SOFTWARE 4

[u]mount(8) exit code: internal mount bug or wrong version

MNT_EX_USER

#define MNT_EX_USER 8

[u]mount(8) exit code: user interrupt

MNT_EX_FILEIO

#define MNT_EX_FILEIO 16

[u]mount(8) exit code: problems writing, locking, ... mtab/utab

MNT_EX_FAIL

#define MNT_EX_FAIL 32

[u]mount(8) exit code: mount failure

MNT_EX_SOMEOK

#define MNT_EX_SOMEOK 64

[u]mount(8) exit code: some mount succeeded; usually when executed with --all options. Never returned by libmount.