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nest-open-source / manifest_repos / util-linux / fbf4d2c62e307b6fc127b2fd02387ad7447ee1ff / . / libmount / src / context.c
blob: d948b12043be18e19b11452a00e3ad6f62eb34ee [file] [log] [blame]
/*
* Copyright (C) 2010,2011,2012 Karel Zak <kzak@redhat.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*/
/**
* SECTION: context
* @title: Library high-level context
* @short_description: high-level API to mount/umount devices.
*
* <informalexample>
* <programlisting>
* struct libmnt_context *cxt = mnt_new_context();
*
* mnt_context_set_options(cxt, "aaa,bbb,ccc=CCC");
* mnt_context_set_mflags(cxt, MS_NOATIME|MS_NOEXEC);
* mnt_context_set_target(cxt, "/mnt/foo");
*
* if (!mnt_context_mount(cxt))
* printf("successfully mounted\n");
* mnt_free_context(cxt);
*
* </programlisting>
* </informalexample>
*
* This code is similar to:
*
* mount -o aaa,bbb,ccc=CCC,noatime,noexec /mnt/foo
*
*/
#include "mountP.h"
#include "fileutils.h"
#include "strutils.h"
#include "namespace.h"
#include <sys/wait.h>
/**
* mnt_new_context:
*
* Returns: newly allocated mount context
*/
struct libmnt_context *mnt_new_context(void)
{
struct libmnt_context *cxt;
uid_t ruid, euid;
cxt = calloc(1, sizeof(*cxt));
if (!cxt)
return NULL;
INIT_LIST_HEAD(&cxt->addmounts);
ruid = getuid();
euid = geteuid();
mnt_context_reset_status(cxt);
cxt->loopdev_fd = -1;
cxt->ns_orig.fd = -1;
cxt->ns_tgt.fd = -1;
cxt->ns_cur = &cxt->ns_orig;
/* if we're really root and aren't running setuid */
cxt->restricted = (uid_t) 0 == ruid && ruid == euid ? 0 : 1;
DBG(CXT, ul_debugobj(cxt, "----> allocate %s",
cxt->restricted ? "[RESTRICTED]" : ""));
return cxt;
}
/**
* mnt_free_context:
* @cxt: mount context
*
* Deallocates context struct.
*/
void mnt_free_context(struct libmnt_context *cxt)
{
if (!cxt)
return;
mnt_reset_context(cxt);
free(cxt->fstype_pattern);
free(cxt->optstr_pattern);
mnt_unref_table(cxt->fstab);
mnt_unref_cache(cxt->cache);
mnt_context_clear_loopdev(cxt);
mnt_free_lock(cxt->lock);
mnt_free_update(cxt->update);
mnt_context_set_target_ns(cxt, NULL);
free(cxt->children);
DBG(CXT, ul_debugobj(cxt, "<---- free"));
free(cxt);
}
/**
* mnt_reset_context:
* @cxt: mount context
*
* Resets all information in the context that is directly related to
* the latest mount (spec, source, target, mount options, ...).
*
* The match patterns, target namespace, 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.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_reset_context(struct libmnt_context *cxt)
{
int fl;
if (!cxt)
return -EINVAL;
DBG(CXT, ul_debugobj(cxt, "<---- reset [status=%d] ---->",
mnt_context_get_status(cxt)));
fl = cxt->flags;
mnt_unref_fs(cxt->fs);
mnt_unref_table(cxt->mtab);
mnt_unref_table(cxt->utab);
free(cxt->helper);
free(cxt->orig_user);
cxt->fs = NULL;
cxt->mtab = NULL;
cxt->utab = NULL;
cxt->helper = NULL;
cxt->orig_user = NULL;
cxt->mountflags = 0;
cxt->user_mountflags = 0;
cxt->mountdata = NULL;
cxt->flags = MNT_FL_DEFAULT;
/* free additional mounts list */
while (!list_empty(&cxt->addmounts)) {
struct libmnt_addmount *ad = list_entry(cxt->addmounts.next,
struct libmnt_addmount,
mounts);
mnt_free_addmount(ad);
}
mnt_context_reset_status(cxt);
if (cxt->table_fltrcb)
mnt_context_set_tabfilter(cxt, NULL, NULL);
/* restore non-resettable flags */
cxt->flags |= (fl & MNT_FL_NOMTAB);
cxt->flags |= (fl & MNT_FL_FAKE);
cxt->flags |= (fl & MNT_FL_SLOPPY);
cxt->flags |= (fl & MNT_FL_VERBOSE);
cxt->flags |= (fl & MNT_FL_NOHELPERS);
cxt->flags |= (fl & MNT_FL_LOOPDEL);
cxt->flags |= (fl & MNT_FL_LAZY);
cxt->flags |= (fl & MNT_FL_FORK);
cxt->flags |= (fl & MNT_FL_FORCE);
cxt->flags |= (fl & MNT_FL_NOCANONICALIZE);
cxt->flags |= (fl & MNT_FL_RDONLY_UMOUNT);
cxt->flags |= (fl & MNT_FL_RWONLY_MOUNT);
cxt->flags |= (fl & MNT_FL_NOSWAPMATCH);
cxt->flags |= (fl & MNT_FL_TABPATHS_CHECKED);
return 0;
}
/**
* mnt_context_reset_status:
* @cxt: context
*
* 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.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_reset_status(struct libmnt_context *cxt)
{
if (!cxt)
return -EINVAL;
cxt->syscall_status = 1; /* means not called yet */
cxt->helper_exec_status = 1;
cxt->helper_status = 0;
return 0;
}
static int context_init_paths(struct libmnt_context *cxt, int writable)
{
struct libmnt_ns *ns_old;
assert(cxt);
#ifdef USE_LIBMOUNT_SUPPORT_MTAB
if (!cxt->mtab_path)
cxt->mtab_path = mnt_get_mtab_path();
#endif
if (!cxt->utab_path)
cxt->utab_path = mnt_get_utab_path();
if (!writable)
return 0; /* only paths wanted */
if (mnt_context_is_nomtab(cxt))
return 0; /* write mode overridden by mount -n */
if (cxt->flags & MNT_FL_TABPATHS_CHECKED)
return 0;
DBG(CXT, ul_debugobj(cxt, "checking for writable tab files"));
cxt->mtab_writable = 0;
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
#ifdef USE_LIBMOUNT_SUPPORT_MTAB
mnt_has_regular_mtab(&cxt->mtab_path, &cxt->mtab_writable);
if (!cxt->mtab_writable)
#endif
/* use /run/mount/utab if /etc/mtab is useless */
mnt_has_regular_utab(&cxt->utab_path, &cxt->utab_writable);
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
cxt->flags |= MNT_FL_TABPATHS_CHECKED;
return 0;
}
int mnt_context_mtab_writable(struct libmnt_context *cxt)
{
assert(cxt);
context_init_paths(cxt, 1);
return cxt->mtab_writable == 1;
}
int mnt_context_utab_writable(struct libmnt_context *cxt)
{
assert(cxt);
context_init_paths(cxt, 1);
return cxt->utab_writable == 1;
}
const char *mnt_context_get_writable_tabpath(struct libmnt_context *cxt)
{
assert(cxt);
context_init_paths(cxt, 1);
return cxt->mtab_writable ? cxt->mtab_path : cxt->utab_path;
}
static int set_flag(struct libmnt_context *cxt, int flag, int enable)
{
if (!cxt)
return -EINVAL;
if (enable) {
DBG(CXT, ul_debugobj(cxt, "enabling flag %04x", flag));
cxt->flags |= flag;
} else {
DBG(CXT, ul_debugobj(cxt, "disabling flag %04x", flag));
cxt->flags &= ~flag;
}
return 0;
}
/**
* mnt_context_is_restricted:
* @cxt: mount context
*
* Returns: 0 for an unrestricted mount (user is root), or 1 for non-root mounts
*/
int mnt_context_is_restricted(struct libmnt_context *cxt)
{
return cxt->restricted;
}
/**
* mnt_context_set_optsmode
* @cxt: mount context
* @mode: MNT_OMODE_* flags
*
* 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_OMODE_USER is always used if mount context is in restricted mode
* - MNT_OMODE_AUTO is used if nothing else is defined
* - the flags are evaluated in this order: MNT_OMODE_NOTAB, MNT_OMODE_FORCE,
* MNT_OMODE_FSTAB, MNT_OMODE_MTAB and then the mount options from fstab/mtab
* are set according to MNT_OMODE_{IGNORE,APPEND,PREPAND,REPLACE}
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_optsmode(struct libmnt_context *cxt, int mode)
{
if (!cxt)
return -EINVAL;
cxt->optsmode = mode;
return 0;
}
/**
* mnt_context_get_optsmode
* @cxt: mount context
*
* Returns: MNT_OMODE_* mask or zero.
*/
int mnt_context_get_optsmode(struct libmnt_context *cxt)
{
return cxt->optsmode;
}
/**
* mnt_context_disable_canonicalize:
* @cxt: mount context
* @disable: TRUE or FALSE
*
* 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).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_disable_canonicalize(struct libmnt_context *cxt, int disable)
{
return set_flag(cxt, MNT_FL_NOCANONICALIZE, disable);
}
/**
* mnt_context_is_nocanonicalize:
* @cxt: mount context
*
* Returns: 1 if no-canonicalize mode is enabled or 0.
*/
int mnt_context_is_nocanonicalize(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_NOCANONICALIZE ? 1 : 0;
}
/**
* mnt_context_enable_lazy:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable lazy umount (see umount(8) man page, option -l).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_lazy(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_LAZY, enable);
}
/**
* mnt_context_is_lazy:
* @cxt: mount context
*
* Returns: 1 if lazy umount is enabled or 0
*/
int mnt_context_is_lazy(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_LAZY ? 1 : 0;
}
/**
* mnt_context_enable_fork:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable fork(2) call in mnt_context_next_mount() (see mount(8) man
* page, option -F).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_fork(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_FORK, enable);
}
/**
* mnt_context_is_fork:
* @cxt: mount context
*
* Returns: 1 if fork (mount -F) is enabled or 0
*/
int mnt_context_is_fork(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_FORK ? 1 : 0;
}
/**
* mnt_context_is_parent:
* @cxt: mount context
*
* Return: 1 if mount -F enabled and the current context is parent, or 0
*/
int mnt_context_is_parent(struct libmnt_context *cxt)
{
return mnt_context_is_fork(cxt) && cxt->pid == 0;
}
/**
* mnt_context_is_child:
* @cxt: mount context
*
* Return: 1 f the current context is child, or 0
*/
int mnt_context_is_child(struct libmnt_context *cxt)
{
/* See mnt_fork_context(), the for fork flag is always disabled
* for children to avoid recursive forking.
*/
return !mnt_context_is_fork(cxt) && cxt->pid;
}
/**
* mnt_context_enable_rdonly_umount:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable read-only remount on failed umount(2)
* (see umount(8) man page, option -r).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_rdonly_umount(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_RDONLY_UMOUNT, enable);
}
/**
* mnt_context_is_rdonly_umount
* @cxt: mount context
*
* See also mnt_context_enable_rdonly_umount() and umount(8) man page,
* option -r.
*
* Returns: 1 if read-only remount failed umount(2) is enables or 0
*/
int mnt_context_is_rdonly_umount(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_RDONLY_UMOUNT ? 1 : 0;
}
/**
* mnt_context_enable_rwonly_mount:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* 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
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_rwonly_mount(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_RWONLY_MOUNT, enable);
}
/**
* mnt_context_is_rwonly_mount
* @cxt: mount context
*
* See also mnt_context_enable_rwonly_mount() and mount(8) man page,
* option -w.
*
* Since: 2.30
*
* Returns: 1 if only read-write mount is allowed.
*/
int mnt_context_is_rwonly_mount(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_RWONLY_MOUNT ? 1 : 0;
}
/**
* mnt_context_forced_rdonly:
* @cxt: mount context
*
* See also mnt_context_enable_rwonly_mount().
*
* Since: 2.30
*
* Returns: 1 if mounted read-only on write-protected device.
*/
int mnt_context_forced_rdonly(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_FORCED_RDONLY ? 1 : 0;
}
/**
* mnt_context_disable_helpers:
* @cxt: mount context
* @disable: TRUE or FALSE
*
* Enable/disable /sbin/[u]mount.* helpers (see mount(8) man page, option -i).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_disable_helpers(struct libmnt_context *cxt, int disable)
{
return set_flag(cxt, MNT_FL_NOHELPERS, disable);
}
/**
* mnt_context_is_nohelpers
* @cxt: mount context
*
* Returns: 1 if helpers are disabled (mount -i) or 0
*/
int mnt_context_is_nohelpers(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_NOHELPERS ? 1 : 0;
}
/**
* mnt_context_enable_sloppy:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Set/unset sloppy mounting (see mount(8) man page, option -s).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_sloppy(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_SLOPPY, enable);
}
/**
* mnt_context_is_sloppy:
* @cxt: mount context
*
* Returns: 1 if sloppy flag is enabled or 0
*/
int mnt_context_is_sloppy(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_SLOPPY ? 1 : 0;
}
/**
* mnt_context_enable_fake:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable fake mounting (see mount(8) man page, option -f).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_fake(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_FAKE, enable);
}
/**
* mnt_context_is_fake:
* @cxt: mount context
*
* Returns: 1 if fake flag is enabled or 0
*/
int mnt_context_is_fake(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_FAKE ? 1 : 0;
}
/**
* mnt_context_disable_mtab:
* @cxt: mount context
* @disable: TRUE or FALSE
*
* Disable/enable mtab update (see mount(8) man page, option -n).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_disable_mtab(struct libmnt_context *cxt, int disable)
{
return set_flag(cxt, MNT_FL_NOMTAB, disable);
}
/**
* mnt_context_is_nomtab:
* @cxt: mount context
*
* Returns: 1 if no-mtab is enabled or 0
*/
int mnt_context_is_nomtab(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_NOMTAB ? 1 : 0;
}
/**
* mnt_context_disable_swapmatch:
* @cxt: mount context
* @disable: TRUE or FALSE
*
* Disable/enable swap between source and target for mount(8) if only one path
* is specified.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_disable_swapmatch(struct libmnt_context *cxt, int disable)
{
return set_flag(cxt, MNT_FL_NOSWAPMATCH, disable);
}
/**
* mnt_context_is_swapmatch:
* @cxt: mount context
*
* Returns: 1 if swap between source and target is allowed (default is 1) or 0.
*/
int mnt_context_is_swapmatch(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_NOSWAPMATCH ? 0 : 1;
}
/**
* mnt_context_enable_force:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable force umounting (see umount(8) man page, option -f).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_force(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_FORCE, enable);
}
/**
* mnt_context_is_force
* @cxt: mount context
*
* Returns: 1 if force umounting flag is enabled or 0
*/
int mnt_context_is_force(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_FORCE ? 1 : 0;
}
/**
* mnt_context_enable_verbose:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable verbose output (TODO: not implemented yet)
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_verbose(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_VERBOSE, enable);
}
/**
* mnt_context_is_verbose
* @cxt: mount context
*
* Returns: 1 if verbose flag is enabled or 0
*/
int mnt_context_is_verbose(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_VERBOSE ? 1 : 0;
}
/**
* mnt_context_enable_loopdel:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable the loop delete (destroy) after umount (see umount(8), option -d)
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_loopdel(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_LOOPDEL, enable);
}
/**
* mnt_context_is_loopdel:
* @cxt: mount context
*
* Returns: 1 if loop device should be deleted after umount (umount -d) or 0.
*/
int mnt_context_is_loopdel(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_LOOPDEL ? 1 : 0;
}
/**
* mnt_context_set_fs:
* @cxt: mount context
* @fs: filesystem description
*
* The mount context uses private @fs by default. This function allows 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.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_fs(struct libmnt_context *cxt, struct libmnt_fs *fs)
{
if (!cxt)
return -EINVAL;
mnt_ref_fs(fs); /* new */
mnt_unref_fs(cxt->fs); /* old */
cxt->fs = fs;
return 0;
}
/**
* mnt_context_get_fs:
* @cxt: mount context
*
* 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.
*
* Returns: pointer to FS description or NULL in case of a calloc() error.
*/
struct libmnt_fs *mnt_context_get_fs(struct libmnt_context *cxt)
{
if (!cxt)
return NULL;
if (!cxt->fs)
cxt->fs = mnt_new_fs();
return cxt->fs;
}
/**
* mnt_context_get_fs_userdata:
* @cxt: mount context
*
* Returns: pointer to userdata or NULL.
*/
void *mnt_context_get_fs_userdata(struct libmnt_context *cxt)
{
return cxt->fs ? mnt_fs_get_userdata(cxt->fs) : NULL;
}
/**
* mnt_context_get_fstab_userdata:
* @cxt: mount context
*
* Returns: pointer to userdata or NULL.
*/
void *mnt_context_get_fstab_userdata(struct libmnt_context *cxt)
{
return cxt->fstab ? mnt_table_get_userdata(cxt->fstab) : NULL;
}
/**
* mnt_context_get_mtab_userdata:
* @cxt: mount context
*
* Returns: pointer to userdata or NULL.
*/
void *mnt_context_get_mtab_userdata(struct libmnt_context *cxt)
{
return cxt->mtab ? mnt_table_get_userdata(cxt->mtab) : NULL;
}
/**
* mnt_context_set_source:
* @cxt: mount context
* @source: mount source (device, directory, UUID, LABEL, ...)
*
* 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).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_source(struct libmnt_context *cxt, const char *source)
{
return mnt_fs_set_source(mnt_context_get_fs(cxt), source);
}
/**
* mnt_context_get_source:
* @cxt: mount context
*
* Returns: returns pointer or NULL in case of error or if not set.
*/
const char *mnt_context_get_source(struct libmnt_context *cxt)
{
return mnt_fs_get_source(mnt_context_get_fs(cxt));
}
/**
* mnt_context_set_target:
* @cxt: mount context
* @target: mountpoint
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_target(struct libmnt_context *cxt, const char *target)
{
return mnt_fs_set_target(mnt_context_get_fs(cxt), target);
}
/**
* mnt_context_get_target:
* @cxt: mount context
*
* Returns: returns pointer or NULL in case of error or if not set.
*/
const char *mnt_context_get_target(struct libmnt_context *cxt)
{
return mnt_fs_get_target(mnt_context_get_fs(cxt));
}
/**
* mnt_context_set_fstype:
* @cxt: mount context
* @fstype: filesystem type
*
* 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().
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_fstype(struct libmnt_context *cxt, const char *fstype)
{
return mnt_fs_set_fstype(mnt_context_get_fs(cxt), fstype);
}
/**
* mnt_context_get_fstype:
* @cxt: mount context
*
* Returns: pointer or NULL in case of error or if not set.
*/
const char *mnt_context_get_fstype(struct libmnt_context *cxt)
{
return mnt_fs_get_fstype(mnt_context_get_fs(cxt));
}
/**
* mnt_context_set_options:
* @cxt: mount context
* @optstr: comma delimited mount options
*
* Note that that MS_MOVE cannot be specified as "string". It's operation that
* is no supported in fstab (etc.)
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_options(struct libmnt_context *cxt, const char *optstr)
{
return mnt_fs_set_options(mnt_context_get_fs(cxt), optstr);
}
/**
* mnt_context_append_options:
* @cxt: mount context
* @optstr: comma delimited mount options
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_append_options(struct libmnt_context *cxt, const char *optstr)
{
return mnt_fs_append_options(mnt_context_get_fs(cxt), optstr);
}
/**
* mnt_context_get_options:
* @cxt: mount context
*
* 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.
*
* Returns: pointer or NULL
*/
const char *mnt_context_get_options(struct libmnt_context *cxt)
{
return mnt_fs_get_options(mnt_context_get_fs(cxt));
}
/**
* mnt_context_set_fstype_pattern:
* @cxt: mount context
* @pattern: FS name pattern (or NULL to reset the current setting)
*
* See mount(8), option -t.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_fstype_pattern(struct libmnt_context *cxt, const char *pattern)
{
char *p = NULL;
if (!cxt)
return -EINVAL;
if (pattern) {
p = strdup(pattern);
if (!p)
return -ENOMEM;
}
free(cxt->fstype_pattern);
cxt->fstype_pattern = p;
return 0;
}
/**
* mnt_context_set_options_pattern:
* @cxt: mount context
* @pattern: options pattern (or NULL to reset the current setting)
*
* See mount(8), option -O.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_options_pattern(struct libmnt_context *cxt, const char *pattern)
{
char *p = NULL;
if (!cxt)
return -EINVAL;
if (pattern) {
p = strdup(pattern);
if (!p)
return -ENOMEM;
}
free(cxt->optstr_pattern);
cxt->optstr_pattern = p;
return 0;
}
/**
* mnt_context_set_fstab:
* @cxt: mount context
* @tb: fstab
*
* The mount context reads /etc/fstab to the private struct libmnt_table by default.
* This function allows 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.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_fstab(struct libmnt_context *cxt, struct libmnt_table *tb)
{
if (!cxt)
return -EINVAL;
mnt_ref_table(tb); /* new */
mnt_unref_table(cxt->fstab); /* old */
cxt->fstab = tb;
return 0;
}
/**
* mnt_context_get_fstab:
* @cxt: mount context
* @tb: returns fstab
*
* See also mnt_table_parse_fstab() for more details about fstab.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_get_fstab(struct libmnt_context *cxt, struct libmnt_table **tb)
{
struct libmnt_ns *ns_old;
if (!cxt)
return -EINVAL;
if (!cxt->fstab) {
int rc;
cxt->fstab = mnt_new_table();
if (!cxt->fstab)
return -ENOMEM;
if (cxt->table_errcb)
mnt_table_set_parser_errcb(cxt->fstab, cxt->table_errcb);
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
mnt_table_set_cache(cxt->fstab, mnt_context_get_cache(cxt));
rc = mnt_table_parse_fstab(cxt->fstab, NULL);
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
if (rc)
return rc;
}
if (tb)
*tb = cxt->fstab;
return 0;
}
/**
* mnt_context_get_mtab:
* @cxt: mount context
* @tb: returns mtab
*
* See also mnt_table_parse_mtab() for more details about mtab/mountinfo. The
* result will be deallocated by mnt_free_context(@cxt).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_get_mtab(struct libmnt_context *cxt, struct libmnt_table **tb)
{
int rc = 0;
struct libmnt_ns *ns_old = NULL;
if (!cxt)
return -EINVAL;
if (!cxt->mtab) {
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
context_init_paths(cxt, 0);
cxt->mtab = mnt_new_table();
if (!cxt->mtab) {
rc = -ENOMEM;
goto end;
}
if (cxt->table_errcb)
mnt_table_set_parser_errcb(cxt->mtab, cxt->table_errcb);
if (cxt->table_fltrcb)
mnt_table_set_parser_fltrcb(cxt->mtab,
cxt->table_fltrcb,
cxt->table_fltrcb_data);
mnt_table_set_cache(cxt->mtab, mnt_context_get_cache(cxt));
/*
* Note that mtab_path is NULL if mtab is useless or unsupported
*/
if (cxt->utab)
/* utab already parsed, don't parse it again */
rc = __mnt_table_parse_mtab(cxt->mtab,
cxt->mtab_path, cxt->utab);
else
rc = mnt_table_parse_mtab(cxt->mtab, cxt->mtab_path);
if (rc)
goto end;
}
if (tb)
*tb = cxt->mtab;
DBG(CXT, ul_debugobj(cxt, "mtab requested [nents=%d]",
mnt_table_get_nents(cxt->mtab)));
end:
if (ns_old && !mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
return rc;
}
/*
* Called by mtab parser to filter out entries, non-zero means that
* an entry has to be filtered out.
*/
static int mtab_filter(struct libmnt_fs *fs, void *data)
{
if (!fs || !data)
return 0;
if (mnt_fs_streq_target(fs, data))
return 0;
if (mnt_fs_streq_srcpath(fs, data))
return 0;
return 1;
}
/*
* The same like mnt_context_get_mtab(), but does not read all mountinfo/mtab
* file, but only entries relevant for @tgt.
*/
int mnt_context_get_mtab_for_target(struct libmnt_context *cxt,
struct libmnt_table **mtab,
const char *tgt)
{
struct stat st;
struct libmnt_cache *cache = NULL;
char *cn_tgt = NULL;
int rc;
struct libmnt_ns *ns_old;
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
if (mnt_context_is_nocanonicalize(cxt))
mnt_context_set_tabfilter(cxt, mtab_filter, (void *) tgt);
else if (mnt_stat_mountpoint(tgt, &st) == 0 && S_ISDIR(st.st_mode)) {
cache = mnt_context_get_cache(cxt);
cn_tgt = mnt_resolve_path(tgt, cache);
if (cn_tgt)
mnt_context_set_tabfilter(cxt, mtab_filter, cn_tgt);
}
rc = mnt_context_get_mtab(cxt, mtab);
mnt_context_set_tabfilter(cxt, NULL, NULL);
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
if (cn_tgt && !cache)
free(cn_tgt);
return rc;
}
/*
* Allows to specify a filter for tab file entries. The filter is called by
* the table parser. Currently used for mtab and utab only.
*/
int mnt_context_set_tabfilter(struct libmnt_context *cxt,
int (*fltr)(struct libmnt_fs *, void *),
void *data)
{
if (!cxt)
return -EINVAL;
cxt->table_fltrcb = fltr;
cxt->table_fltrcb_data = data;
if (cxt->mtab)
mnt_table_set_parser_fltrcb(cxt->mtab,
cxt->table_fltrcb,
cxt->table_fltrcb_data);
DBG(CXT, ul_debugobj(cxt, "tabfilter %s", fltr ? "ENABLED!" : "disabled"));
return 0;
}
/**
* mnt_context_get_table:
* @cxt: mount context
* @filename: e.g. /proc/self/mountinfo
* @tb: returns the table
*
* 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).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_get_table(struct libmnt_context *cxt,
const char *filename, struct libmnt_table **tb)
{
int rc;
struct libmnt_ns *ns_old;
if (!cxt || !tb)
return -EINVAL;
*tb = mnt_new_table();
if (!*tb)
return -ENOMEM;
if (cxt->table_errcb)
mnt_table_set_parser_errcb(*tb, cxt->table_errcb);
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
rc = mnt_table_parse_file(*tb, filename);
if (rc) {
mnt_unref_table(*tb);
goto end;
}
mnt_table_set_cache(*tb, mnt_context_get_cache(cxt));
end:
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
return rc;
}
/**
* mnt_context_set_tables_errcb
* @cxt: mount context
* @cb: pointer to callback function
*
* 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().
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_tables_errcb(struct libmnt_context *cxt,
int (*cb)(struct libmnt_table *tb, const char *filename, int line))
{
if (!cxt)
return -EINVAL;
if (cxt->mtab)
mnt_table_set_parser_errcb(cxt->mtab, cb);
if (cxt->fstab)
mnt_table_set_parser_errcb(cxt->fstab, cb);
cxt->table_errcb = cb;
return 0;
}
/**
* mnt_context_set_cache:
* @cxt: mount context
* @cache: cache instance or NULL
*
* The mount context maintains a private struct libmnt_cache by default. This
* function allows 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.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_cache(struct libmnt_context *cxt, struct libmnt_cache *cache)
{
if (!cxt)
return -EINVAL;
mnt_ref_cache(cache); /* new */
mnt_unref_cache(cxt->cache); /* old */
cxt->cache = cache;
if (cxt->mtab)
mnt_table_set_cache(cxt->mtab, cache);
if (cxt->fstab)
mnt_table_set_cache(cxt->fstab, cache);
return 0;
}
/**
* mnt_context_get_cache
* @cxt: mount context
*
* See also mnt_context_set_cache().
*
* Returns: pointer to cache or NULL if canonicalization is disabled.
*/
struct libmnt_cache *mnt_context_get_cache(struct libmnt_context *cxt)
{
if (!cxt || mnt_context_is_nocanonicalize(cxt))
return NULL;
if (!cxt->cache) {
struct libmnt_cache *cache = mnt_new_cache();
mnt_context_set_cache(cxt, cache);
mnt_unref_cache(cache);
}
return cxt->cache;
}
/**
* mnt_context_set_passwd_cb:
* @cxt: mount context
* @get: callback to get password
* @release: callback to release (deallocate) password
*
* Sets callbacks for encryption password (e.g encrypted loopdev). This
* function is deprecated (encrypted loops are no longer supported).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_passwd_cb(struct libmnt_context *cxt,
char *(*get)(struct libmnt_context *),
void (*release)(struct libmnt_context *, char *))
{
if (!cxt)
return -EINVAL;
cxt->pwd_get_cb = get;
cxt->pwd_release_cb = release;
return 0;
}
/**
* mnt_context_get_lock:
* @cxt: mount context
*
* 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.
*
* Returns: pointer to lock struct or NULL.
*/
struct libmnt_lock *mnt_context_get_lock(struct libmnt_context *cxt)
{
/*
* DON'T call this function within libmount, it will always allocate
* the lock. The mnt_update_* functions are able to allocate the lock
* only when mtab/utab update is really necessary.
*/
if (!cxt || mnt_context_is_nomtab(cxt))
return NULL;
if (!cxt->lock) {
cxt->lock = mnt_new_lock(
mnt_context_get_writable_tabpath(cxt), 0);
if (cxt->lock)
mnt_lock_block_signals(cxt->lock, TRUE);
}
return cxt->lock;
}
/**
* mnt_context_set_mflags:
* @cxt: mount context
* @flags: mount(2) flags (MS_* flags)
*
* Sets mount flags (see mount(2) man page).
*
* Note that mount context allows 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.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_mflags(struct libmnt_context *cxt, unsigned long flags)
{
if (!cxt)
return -EINVAL;
cxt->mountflags = flags;
if ((cxt->flags & MNT_FL_MOUNTOPTS_FIXED) && cxt->fs)
/*
* the final mount options are already generated, refresh...
*/
return mnt_optstr_apply_flags(
&cxt->fs->vfs_optstr,
cxt->mountflags,
mnt_get_builtin_optmap(MNT_LINUX_MAP));
return 0;
}
/**
* mnt_context_get_mflags:
* @cxt: mount context
* @flags: returns MS_* mount flags
*
* Converts mount options string to MS_* flags and bitwise-OR the result with
* the already defined flags (see mnt_context_set_mflags()).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_get_mflags(struct libmnt_context *cxt, unsigned long *flags)
{
int rc = 0;
struct list_head *p;
if (!cxt || !flags)
return -EINVAL;
*flags = 0;
if (!(cxt->flags & MNT_FL_MOUNTFLAGS_MERGED) && cxt->fs) {
const char *o = mnt_fs_get_options(cxt->fs);
if (o)
rc = mnt_optstr_get_flags(o, flags,
mnt_get_builtin_optmap(MNT_LINUX_MAP));
}
list_for_each(p, &cxt->addmounts) {
struct libmnt_addmount *ad =
list_entry(p, struct libmnt_addmount, mounts);
*flags |= ad->mountflags;
}
if (!rc)
*flags |= cxt->mountflags;
return rc;
}
/**
* mnt_context_set_user_mflags:
* @cxt: mount context
* @flags: mount(2) flags (MNT_MS_* flags, e.g. MNT_MS_LOOP)
*
* Sets userspace mount flags.
*
* See also notes for mnt_context_set_mflags().
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_user_mflags(struct libmnt_context *cxt, unsigned long flags)
{
if (!cxt)
return -EINVAL;
cxt->user_mountflags = flags;
return 0;
}
/**
* mnt_context_get_user_mflags:
* @cxt: mount context
* @flags: returns mount 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()).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_get_user_mflags(struct libmnt_context *cxt, unsigned long *flags)
{
int rc = 0;
if (!cxt || !flags)
return -EINVAL;
*flags = 0;
if (!(cxt->flags & MNT_FL_MOUNTFLAGS_MERGED) && cxt->fs) {
const char *o = mnt_fs_get_user_options(cxt->fs);
if (o)
rc = mnt_optstr_get_flags(o, flags,
mnt_get_builtin_optmap(MNT_USERSPACE_MAP));
}
if (!rc)
*flags |= cxt->user_mountflags;
return rc;
}
/**
* mnt_context_set_mountdata:
* @cxt: mount context
* @data: mount(2) data
*
* The mount context generates mountdata from mount options by default. This
* function allows 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.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_set_mountdata(struct libmnt_context *cxt, void *data)
{
if (!cxt)
return -EINVAL;
cxt->mountdata = data;
cxt->flags |= MNT_FL_MOUNTDATA;
return 0;
}
/*
* Translates LABEL/UUID/path to mountable path
*/
int mnt_context_prepare_srcpath(struct libmnt_context *cxt)
{
const char *path = NULL;
struct libmnt_cache *cache;
const char *t, *v, *src;
int rc = 0;
struct libmnt_ns *ns_old;
assert(cxt);
assert(cxt->fs);
assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
DBG(CXT, ul_debugobj(cxt, "preparing source path"));
src = mnt_fs_get_source(cxt->fs);
if (!src && mnt_context_propagation_only(cxt))
/* mount --make-{shared,private,...} */
return mnt_fs_set_source(cxt->fs, "none");
/* ignore filesystems without source or filesystems
* where the source is a quasi-path (//foo/bar)
*/
if (!src || mnt_fs_is_netfs(cxt->fs))
return 0;
DBG(CXT, ul_debugobj(cxt, "srcpath '%s'", src));
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
cache = mnt_context_get_cache(cxt);
if (!mnt_fs_get_tag(cxt->fs, &t, &v)) {
/*
* Source is TAG (evaluate)
*/
if (cache)
path = mnt_resolve_tag(t, v, cache);
rc = path ? mnt_fs_set_source(cxt->fs, path) : -MNT_ERR_NOSOURCE;
} else if (cache && !mnt_fs_is_pseudofs(cxt->fs)) {
/*
* Source is PATH (canonicalize)
*/
path = mnt_resolve_path(src, cache);
if (path && strcmp(path, src))
rc = mnt_fs_set_source(cxt->fs, path);
}
if (rc) {
DBG(CXT, ul_debugobj(cxt, "failed to prepare srcpath [rc=%d]", rc));
goto end;
}
if (!path)
path = src;
if ((cxt->mountflags & (MS_BIND | MS_MOVE | MS_REMOUNT))
|| mnt_fs_is_pseudofs(cxt->fs)) {
DBG(CXT, ul_debugobj(cxt, "REMOUNT/BIND/MOVE/pseudo FS source: %s", path));
goto end;
}
/*
* Initialize loop device
*/
if (mnt_context_is_loopdev(cxt)) {
rc = mnt_context_setup_loopdev(cxt);
if (rc)
goto end;
}
DBG(CXT, ul_debugobj(cxt, "final srcpath '%s'",
mnt_fs_get_source(cxt->fs)));
end:
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
return rc;
}
/* create a mountpoint if X-mount.mkdir[=<mode>] specified */
static int mkdir_target(const char *tgt, struct libmnt_fs *fs)
{
char *mstr = NULL;
size_t mstr_sz = 0;
mode_t mode = 0;
struct stat st;
int rc;
assert(tgt);
assert(fs);
if (mnt_optstr_get_option(fs->user_optstr, "X-mount.mkdir", &mstr, &mstr_sz) != 0 &&
mnt_optstr_get_option(fs->user_optstr, "x-mount.mkdir", &mstr, &mstr_sz) != 0) /* obsolete */
return 0;
DBG(CXT, ul_debug("mkdir %s (%s) wanted", tgt, mstr));
if (mnt_stat_mountpoint(tgt, &st) == 0)
return 0;
if (mstr && mstr_sz) {
char *end = NULL;
errno = 0;
mode = strtol(mstr, &end, 8);
if (errno || !end || mstr + mstr_sz != end) {
DBG(CXT, ul_debug("failed to parse mkdir mode '%s'", mstr));
return -MNT_ERR_MOUNTOPT;
}
}
if (!mode)
mode = S_IRWXU | /* 0755 */
S_IRGRP | S_IXGRP |
S_IROTH | S_IXOTH;
rc = mkdir_p(tgt, mode);
if (rc)
DBG(CXT, ul_debug("mkdir %s failed: %m", tgt));
return rc;
}
int mnt_context_prepare_target(struct libmnt_context *cxt)
{
const char *tgt;
struct libmnt_cache *cache;
int rc = 0;
struct libmnt_ns *ns_old;
assert(cxt);
assert(cxt->fs);
assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
DBG(CXT, ul_debugobj(cxt, "preparing target path"));
tgt = mnt_fs_get_target(cxt->fs);
if (!tgt)
return 0;
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
/* mkdir target */
if (cxt->action == MNT_ACT_MOUNT
&& !mnt_context_is_restricted(cxt)
&& (cxt->user_mountflags & MNT_MS_XCOMMENT ||
cxt->user_mountflags & MNT_MS_XFSTABCOMM)) {
rc = mkdir_target(tgt, cxt->fs);
if (rc) {
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
return rc; /* mkdir or parse error */
}
}
/* canonicalize the path */
cache = mnt_context_get_cache(cxt);
if (cache) {
char *path = mnt_resolve_path(tgt, cache);
if (path && strcmp(path, tgt) != 0)
rc = mnt_fs_set_target(cxt->fs, path);
}
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
if (rc)
DBG(CXT, ul_debugobj(cxt, "failed to prepare target '%s'", tgt));
else
DBG(CXT, ul_debugobj(cxt, "final target '%s'",
mnt_fs_get_target(cxt->fs)));
return 0;
}
/* Guess type, but not set to cxt->fs, always use free() for the result. It's
* no error when we're not able to guess a filesystem type. Note that error
* does not mean that result in @type is NULL.
*/
int mnt_context_guess_srcpath_fstype(struct libmnt_context *cxt, char **type)
{
int rc = 0;
struct libmnt_ns *ns_old;
const char *dev = mnt_fs_get_srcpath(cxt->fs);
*type = NULL;
if (!dev)
goto done;
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
if (access(dev, F_OK) == 0) {
struct libmnt_cache *cache = mnt_context_get_cache(cxt);
int ambi = 0;
*type = mnt_get_fstype(dev, &ambi, cache);
if (cache && *type)
*type = strdup(*type);
if (ambi)
rc = -MNT_ERR_AMBIFS;
} else {
DBG(CXT, ul_debugobj(cxt, "access(%s) failed [%m]", dev));
if (strchr(dev, ':') != NULL)
*type = strdup("nfs");
else if (!strncmp(dev, "//", 2))
*type = strdup("cifs");
}
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
done:
return rc;
}
/*
* It's usually no error when we're not able to detect the filesystem type -- we
* will try to use the types from /{etc,proc}/filesystems.
*/
int mnt_context_guess_fstype(struct libmnt_context *cxt)
{
char *type;
int rc = 0;
assert(cxt);
assert(cxt->fs);
assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
DBG(CXT, ul_debugobj(cxt, "preparing fstype"));
if ((cxt->mountflags & (MS_BIND | MS_MOVE))
|| mnt_context_propagation_only(cxt))
goto none;
type = (char *) mnt_fs_get_fstype(cxt->fs);
if (type && !strcmp(type, "auto")) {
mnt_fs_set_fstype(cxt->fs, NULL);
type = NULL;
}
if (type)
goto done;
if (cxt->mountflags & MS_REMOUNT)
goto none;
if (cxt->fstype_pattern)
goto done;
rc = mnt_context_guess_srcpath_fstype(cxt, &type);
if (rc == 0 && type)
__mnt_fs_set_fstype_ptr(cxt->fs, type);
else
free(type);
done:
DBG(CXT, ul_debugobj(cxt, "FS type: %s [rc=%d]",
mnt_fs_get_fstype(cxt->fs), rc));
return rc;
none:
return mnt_fs_set_fstype(cxt->fs, "none");
}
/*
* The default is to use fstype from cxt->fs, this could be overwritten by
* @type. The @act is MNT_ACT_{MOUNT,UMOUNT}.
*
* Returns: 0 on success or negative number in case of error. Note that success
* does not mean that there is any usable helper, you have to check cxt->helper.
*/
int mnt_context_prepare_helper(struct libmnt_context *cxt, const char *name,
const char *type)
{
char search_path[] = FS_SEARCH_PATH; /* from config.h */
char *p = NULL, *path;
struct libmnt_ns *ns_old;
assert(cxt);
assert(cxt->fs);
assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
if (!type)
type = mnt_fs_get_fstype(cxt->fs);
if (type && strchr(type, ','))
return 0; /* type is fstype pattern */
if (mnt_context_is_nohelpers(cxt)
|| !type
|| !strcmp(type, "none")
|| strstr(type, "/..") /* don't try to smuggle path */
|| mnt_fs_is_swaparea(cxt->fs))
return 0;
ns_old = mnt_context_switch_origin_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
path = strtok_r(search_path, ":", &p);
while (path) {
char helper[PATH_MAX];
struct stat st;
int rc;
rc = snprintf(helper, sizeof(helper), "%s/%s.%s",
path, name, type);
path = strtok_r(NULL, ":", &p);
if (rc < 0 || (size_t) rc >= sizeof(helper))
continue;
rc = stat(helper, &st);
if (rc == -1 && errno == ENOENT && strchr(type, '.')) {
/* If type ends with ".subtype" try without it */
char *hs = strrchr(helper, '.');
if (hs)
*hs = '\0';
rc = stat(helper, &st);
}
DBG(CXT, ul_debugobj(cxt, "%-25s ... %s", helper,
rc ? "not found" : "found"));
if (rc)
continue;
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
free(cxt->helper);
cxt->helper = strdup(helper);
if (!cxt->helper)
return -ENOMEM;
return 0;
}
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
return 0;
}
int mnt_context_merge_mflags(struct libmnt_context *cxt)
{
unsigned long fl = 0;
int rc;
assert(cxt);
DBG(CXT, ul_debugobj(cxt, "merging mount flags"));
rc = mnt_context_get_mflags(cxt, &fl);
if (rc)
return rc;
cxt->mountflags = fl;
fl = 0;
rc = mnt_context_get_user_mflags(cxt, &fl);
if (rc)
return rc;
cxt->user_mountflags = fl;
DBG(CXT, ul_debugobj(cxt, "final flags: VFS=%08lx user=%08lx",
cxt->mountflags, cxt->user_mountflags));
cxt->flags |= MNT_FL_MOUNTFLAGS_MERGED;
return 0;
}
/*
* Prepare /etc/mtab or /run/mount/utab
*/
int mnt_context_prepare_update(struct libmnt_context *cxt)
{
int rc;
const char *target;
assert(cxt);
assert(cxt->fs);
assert(cxt->action);
assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
DBG(CXT, ul_debugobj(cxt, "prepare update"));
if (mnt_context_propagation_only(cxt)) {
DBG(CXT, ul_debugobj(cxt, "skip update: only MS_PROPAGATION"));
return 0;
}
target = mnt_fs_get_target(cxt->fs);
if (cxt->action == MNT_ACT_UMOUNT && target && !strcmp(target, "/")) {
DBG(CXT, ul_debugobj(cxt, "root umount: setting NOMTAB"));
mnt_context_disable_mtab(cxt, TRUE);
}
if (mnt_context_is_nomtab(cxt)) {
DBG(CXT, ul_debugobj(cxt, "skip update: NOMTAB flag"));
return 0;
}
if (!mnt_context_get_writable_tabpath(cxt)) {
DBG(CXT, ul_debugobj(cxt, "skip update: no writable destination"));
return 0;
}
/* 0 = success, 1 = not called yet */
if (cxt->syscall_status != 1 && cxt->syscall_status != 0) {
DBG(CXT, ul_debugobj(cxt,
"skip update: syscall failed [status=%d]",
cxt->syscall_status));
return 0;
}
if (!cxt->update) {
const char *name = mnt_context_get_writable_tabpath(cxt);
if (cxt->action == MNT_ACT_UMOUNT && is_file_empty(name)) {
DBG(CXT, ul_debugobj(cxt,
"skip update: umount, no table"));
return 0;
}
cxt->update = mnt_new_update();
if (!cxt->update)
return -ENOMEM;
mnt_update_set_filename(cxt->update, name,
!mnt_context_mtab_writable(cxt));
}
if (cxt->action == MNT_ACT_UMOUNT)
rc = mnt_update_set_fs(cxt->update, cxt->mountflags,
mnt_context_get_target(cxt), NULL);
else
rc = mnt_update_set_fs(cxt->update, cxt->mountflags,
NULL, cxt->fs);
return rc < 0 ? rc : 0;
}
int mnt_context_update_tabs(struct libmnt_context *cxt)
{
unsigned long fl;
int rc = 0;
struct libmnt_ns *ns_old;
assert(cxt);
if (mnt_context_is_nomtab(cxt)) {
DBG(CXT, ul_debugobj(cxt, "don't update: NOMTAB flag"));
return 0;
}
if (!cxt->update || !mnt_update_is_ready(cxt->update)) {
DBG(CXT, ul_debugobj(cxt, "don't update: no update prepared"));
return 0;
}
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
/* check utab update when external helper executed */
if (mnt_context_helper_executed(cxt)
&& mnt_context_get_helper_status(cxt) == 0
&& mnt_context_utab_writable(cxt)) {
if (mnt_update_already_done(cxt->update, cxt->lock)) {
DBG(CXT, ul_debugobj(cxt, "don't update: error evaluate or already updated"));
goto end;
}
} else if (cxt->helper) {
DBG(CXT, ul_debugobj(cxt, "don't update: external helper"));
goto end;
}
if (cxt->syscall_status != 0
&& !(mnt_context_helper_executed(cxt) &&
mnt_context_get_helper_status(cxt) == 0)) {
DBG(CXT, ul_debugobj(cxt, "don't update: syscall/helper failed/not called"));
goto end;
}
fl = mnt_update_get_mflags(cxt->update);
if ((cxt->mountflags & MS_RDONLY) != (fl & MS_RDONLY))
/*
* fix MS_RDONLY in options
*/
mnt_update_force_rdonly(cxt->update,
cxt->mountflags & MS_RDONLY);
rc = mnt_update_table(cxt->update, cxt->lock);
end:
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
return rc;
}
static int apply_table(struct libmnt_context *cxt, struct libmnt_table *tb,
int direction)
{
struct libmnt_fs *fs = NULL;
const char *src, *tgt;
int rc;
assert(cxt);
assert(cxt->fs);
src = mnt_fs_get_source(cxt->fs);
tgt = mnt_fs_get_target(cxt->fs);
if (tgt && src)
fs = mnt_table_find_pair(tb, src, tgt, direction);
else {
if (src)
fs = mnt_table_find_source(tb, src, direction);
else if (tgt)
fs = mnt_table_find_target(tb, tgt, direction);
if (!fs && mnt_context_is_swapmatch(cxt)) {
/* swap source and target (if @src is not LABEL/UUID),
* for example in
*
* mount /foo/bar
*
* the path could be a mountpoint as well as a source (for
* example bind mount, symlink to a device, ...).
*/
if (src && !mnt_fs_get_tag(cxt->fs, NULL, NULL))
fs = mnt_table_find_target(tb, src, direction);
if (!fs && tgt)
fs = mnt_table_find_source(tb, tgt, direction);
}
}
if (!fs)
return -MNT_ERR_NOFSTAB; /* not found */
DBG(CXT, ul_debugobj(cxt, "apply entry:"));
DBG(CXT, mnt_fs_print_debug(fs, stderr));
/* copy from tab to our FS description
*/
rc = mnt_fs_set_source(cxt->fs, mnt_fs_get_source(fs));
if (!rc)
rc = mnt_fs_set_target(cxt->fs, mnt_fs_get_target(fs));
if (!rc && !mnt_fs_get_fstype(cxt->fs))
rc = mnt_fs_set_fstype(cxt->fs, mnt_fs_get_fstype(fs));
if (!rc && !mnt_fs_get_root(cxt->fs) && mnt_fs_get_root(fs))
rc = mnt_fs_set_root(cxt->fs, mnt_fs_get_root(fs));
if (rc)
return rc;
if (cxt->optsmode & MNT_OMODE_IGNORE)
;
else if (cxt->optsmode & MNT_OMODE_REPLACE)
rc = mnt_fs_set_options(cxt->fs, mnt_fs_get_options(fs));
else if (cxt->optsmode & MNT_OMODE_APPEND)
rc = mnt_fs_append_options(cxt->fs, mnt_fs_get_options(fs));
else if (cxt->optsmode & MNT_OMODE_PREPEND)
rc = mnt_fs_prepend_options(cxt->fs, mnt_fs_get_options(fs));
if (!rc)
cxt->flags |= MNT_FL_TAB_APPLIED;
return rc;
}
/**
* mnt_context_apply_fstab:
* @cxt: mount context
*
* This function is optional.
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_apply_fstab(struct libmnt_context *cxt)
{
int rc = -1, isremount = 0, iscmdbind = 0;
struct libmnt_ns *ns_old;
struct libmnt_table *tab = NULL;
const char *src = NULL, *tgt = NULL;
unsigned long mflags = 0;
if (!cxt || !cxt->fs)
return -EINVAL;
if (mnt_context_tab_applied(cxt)) { /* already applied */
DBG(CXT, ul_debugobj(cxt, "fstab already applied -- skip"));
return 0;
}
if (mnt_context_is_restricted(cxt)) {
DBG(CXT, ul_debugobj(cxt, "force fstab usage for non-root users!"));
cxt->optsmode = MNT_OMODE_USER;
} else if (cxt->optsmode == 0) {
DBG(CXT, ul_debugobj(cxt, "use default optsmode"));
cxt->optsmode = MNT_OMODE_AUTO;
} else if (cxt->optsmode & MNT_OMODE_NOTAB) {
cxt->optsmode &= ~MNT_OMODE_FSTAB;
cxt->optsmode &= ~MNT_OMODE_MTAB;
cxt->optsmode &= ~MNT_OMODE_FORCE;
}
if (mnt_context_get_mflags(cxt, &mflags) == 0) {
isremount = !!(mflags & MS_REMOUNT);
iscmdbind = !!(mflags & MS_BIND);
}
if (cxt->fs) {
src = mnt_fs_get_source(cxt->fs);
tgt = mnt_fs_get_target(cxt->fs);
}
DBG(CXT, ul_debugobj(cxt, "OPTSMODE: ignore=%d, append=%d, prepend=%d, "
"replace=%d, force=%d, fstab=%d, mtab=%d",
cxt->optsmode & MNT_OMODE_IGNORE ? 1 : 0,
cxt->optsmode & MNT_OMODE_APPEND ? 1 : 0,
cxt->optsmode & MNT_OMODE_PREPEND ? 1 : 0,
cxt->optsmode & MNT_OMODE_REPLACE ? 1 : 0,
cxt->optsmode & MNT_OMODE_FORCE ? 1 : 0,
cxt->optsmode & MNT_OMODE_FSTAB ? 1 : 0,
cxt->optsmode & MNT_OMODE_MTAB ? 1 : 0));
/* fstab is not required if source and target are specified */
if (src && tgt && !(cxt->optsmode & MNT_OMODE_FORCE)) {
DBG(CXT, ul_debugobj(cxt, "fstab not required -- skip"));
return 0;
}
if (!src && tgt
&& !(cxt->optsmode & MNT_OMODE_FSTAB)
&& !(cxt->optsmode & MNT_OMODE_MTAB)) {
DBG(CXT, ul_debugobj(cxt, "only target; fstab/mtab not required "
"-- skip, probably MS_PROPAGATION"));
return 0;
}
/* let's initialize cxt->fs */
ignore_result( mnt_context_get_fs(cxt) );
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
/* try fstab */
if (cxt->optsmode & MNT_OMODE_FSTAB) {
DBG(CXT, ul_debugobj(cxt, "trying to apply fstab (src=%s, target=%s)", src, tgt));
rc = mnt_context_get_fstab(cxt, &tab);
if (!rc)
rc = apply_table(cxt, tab, MNT_ITER_FORWARD);
}
/* try mtab */
if (rc < 0 && (cxt->optsmode & MNT_OMODE_MTAB)
&& (isremount || cxt->action == MNT_ACT_UMOUNT)) {
DBG(CXT, ul_debugobj(cxt, "trying to apply mtab (src=%s, target=%s)", src, tgt));
if (tgt)
rc = mnt_context_get_mtab_for_target(cxt, &tab, tgt);
else
rc = mnt_context_get_mtab(cxt, &tab);
if (!rc)
rc = apply_table(cxt, tab, MNT_ITER_BACKWARD);
}
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
if (rc) {
if (!mnt_context_is_restricted(cxt)
&& tgt && !src
&& isremount) {
DBG(CXT, ul_debugobj(cxt, "only target; ignore missing mtab entry on remount"));
return 0;
}
DBG(CXT, ul_debugobj(cxt, "failed to find entry in fstab/mtab [rc=%d]: %m", rc));
/* force to "not found in fstab/mtab" error, the details why
* not found are not so important and may be misinterpreted by
* applications... */
rc = -MNT_ERR_NOFSTAB;
} else if (isremount && !iscmdbind) {
/* remove "bind" from fstab (or no-op if not present) */
mnt_optstr_remove_option(&cxt->fs->optstr, "bind");
}
return rc;
}
/**
* mnt_context_tab_applied:
* @cxt: mount context
*
* Returns: 1 if fstab (or mtab) has been applied to the context, or 0.
*/
int mnt_context_tab_applied(struct libmnt_context *cxt)
{
return cxt->flags & MNT_FL_TAB_APPLIED;
}
/*
* This is not a public function!
*
* Returns 1 if *only propagation flags* change is requested.
*/
int mnt_context_propagation_only(struct libmnt_context *cxt)
{
if (cxt->action != MNT_ACT_MOUNT)
return 0;
/* has to be called after context_mount.c: fix_opts() */
assert((cxt->flags & MNT_FL_MOUNTOPTS_FIXED));
/* all propagation mounts are in cxt->addmount */
return !list_empty(&cxt->addmounts)
&& (cxt->mountflags == 0 || cxt->mountflags == MS_SILENT)
&& cxt->fs
&& (!cxt->fs->fstype || strcmp(cxt->fs->fstype, "none") == 0)
&& (!cxt->fs->source || strcmp(cxt->fs->source, "none") == 0);
}
/**
* mnt_context_get_status:
* @cxt: mount context
*
* 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.
*
* Returns: 1 if mount.type or mount(2) syscall has been successfully called.
*/
int mnt_context_get_status(struct libmnt_context *cxt)
{
return !cxt->syscall_status || !cxt->helper_exec_status;
}
/**
* mnt_context_helper_executed:
* @cxt: mount context
*
* Returns: 1 if mount.type helper has been executed, or 0.
*/
int mnt_context_helper_executed(struct libmnt_context *cxt)
{
return cxt->helper_exec_status != 1;
}
/**
* mnt_context_get_helper_status:
* @cxt: mount context
*
* Return: mount.type helper exit status, result is reliable only if
* mnt_context_helper_executed() returns 1.
*/
int mnt_context_get_helper_status(struct libmnt_context *cxt)
{
return cxt->helper_status;
}
/**
* mnt_context_syscall_called:
* @cxt: mount context
*
* Returns: 1 if mount(2) syscall has been called, or 0.
*/
int mnt_context_syscall_called(struct libmnt_context *cxt)
{
return cxt->syscall_status != 1;
}
/**
* mnt_context_get_syscall_errno:
* @cxt: mount context
*
* The result from this function is reliable only if
* mnt_context_syscall_called() returns 1.
*
* Returns: mount(2) errno if the syscall failed or 0.
*/
int mnt_context_get_syscall_errno(struct libmnt_context *cxt)
{
if (cxt->syscall_status < 0)
return -cxt->syscall_status;
return 0;
}
/**
* mnt_context_set_syscall_status:
* @cxt: mount context
* @status: mount(2) 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.
*
* Returns: 0 or negative number in case of error.
*/
int mnt_context_set_syscall_status(struct libmnt_context *cxt, int status)
{
if (!cxt)
return -EINVAL;
DBG(CXT, ul_debugobj(cxt, "syscall status set to: %d", status));
cxt->syscall_status = status;
return 0;
}
/**
* mnt_context_strerror
* @cxt: context
* @buf: buffer
* @bufsiz: size of the buffer
*
* Not implemented, deprecated in favor or mnt_context_get_excode().
*
* Returns: 0 or negative number in case of error.
*/
int mnt_context_strerror(struct libmnt_context *cxt __attribute__((__unused__)),
char *buf __attribute__((__unused__)),
size_t bufsiz __attribute__((__unused__)))
{
/* TODO: based on cxt->syscall_errno or cxt->helper_status */
return 0;
}
int mnt_context_get_generic_excode(int rc, char *buf, size_t bufsz, char *fmt, ...)
{
va_list va;
if (rc == 0)
return MNT_EX_SUCCESS;
va_start(va, fmt);
/* we need to support "%m" */
errno = rc < 0 ? -rc : rc;
if (buf)
vsnprintf(buf, bufsz, fmt, va);
switch (errno) {
case EINVAL:
case EPERM:
rc = MNT_EX_USAGE;
break;
case ENOMEM:
rc = MNT_EX_SYSERR;
break;
default:
rc = MNT_EX_FAIL;
break;
}
va_end(va);
return rc;
}
/**
* mnt_context_get_excode:
* @cxt: context
* @rc: return code of the previous operation
* @buf: buffer to print error message (optional)
* @bufsz: size of the buffer
*
* 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
*
* Returns: MNT_EX_* codes.
*/
int mnt_context_get_excode(
struct libmnt_context *cxt,
int rc,
char *buf,
size_t bufsz)
{
if (buf) {
*buf = '\0'; /* for sure */
if (!cxt->enabled_textdomain) {
bindtextdomain(LIBMOUNT_TEXTDOMAIN, LOCALEDIR);
cxt->enabled_textdomain = 1;
}
}
switch (cxt->action) {
case MNT_ACT_MOUNT:
rc = mnt_context_get_mount_excode(cxt, rc, buf, bufsz);
break;
case MNT_ACT_UMOUNT:
rc = mnt_context_get_umount_excode(cxt, rc, buf, bufsz);
break;
default:
if (rc)
rc = mnt_context_get_generic_excode(rc, buf, bufsz,
_("operation failed: %m"));
else
rc = MNT_EX_SUCCESS;
break;
}
DBG(CXT, ul_debugobj(cxt, "excode: rc=%d message=\"%s\"", rc,
buf ? buf : "<no-message>"));
return rc;
}
/**
* mnt_context_init_helper
* @cxt: mount context
* @action: MNT_ACT_{UMOUNT,MOUNT}
* @flags: not used now
*
* 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);
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_init_helper(struct libmnt_context *cxt, int action,
int flags __attribute__((__unused__)))
{
int rc;
if (!cxt)
return -EINVAL;
rc = mnt_context_disable_helpers(cxt, TRUE);
if (!rc)
rc = set_flag(cxt, MNT_FL_HELPER, 1);
if (!rc)
cxt->action = action;
DBG(CXT, ul_debugobj(cxt, "initialized for [u]mount.<type> helper [rc=%d]", rc));
return rc;
}
/**
* mnt_context_helper_setopt:
* @cxt: context
* @c: getopt() result
* @arg: getopt() optarg
*
* 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.
*
* Returns: negative number on error, 1 if @c is unknown option, 0 on success.
*/
int mnt_context_helper_setopt(struct libmnt_context *cxt, int c, char *arg)
{
if (cxt) {
switch(cxt->action) {
case MNT_ACT_MOUNT:
return mnt_context_mount_setopt(cxt, c, arg);
case MNT_ACT_UMOUNT:
return mnt_context_umount_setopt(cxt, c, arg);
}
}
return -EINVAL;
}
/**
* mnt_context_is_fs_mounted:
* @cxt: context
* @fs: filesystem
* @mounted: returns 1 for mounted and 0 for non-mounted filesystems
*
* Please, read the mnt_table_is_fs_mounted() description!
*
* Returns: 0 on success and negative number in case of error.
*/
int mnt_context_is_fs_mounted(struct libmnt_context *cxt,
struct libmnt_fs *fs, int *mounted)
{
struct libmnt_table *mtab, *orig;
int rc;
struct libmnt_ns *ns_old;
if (!cxt || !fs || !mounted)
return -EINVAL;
ns_old = mnt_context_switch_target_ns(cxt);
if (!ns_old)
return -MNT_ERR_NAMESPACE;
orig = cxt->mtab;
rc = mnt_context_get_mtab(cxt, &mtab);
if (rc == -ENOENT && mnt_fs_streq_target(fs, "/proc") &&
(!cxt->mtab_path || startswith(cxt->mtab_path, "/proc/"))) {
if (!orig) {
mnt_unref_table(cxt->mtab);
cxt->mtab = NULL;
}
*mounted = 0;
return 0; /* /proc not mounted */
} else if (rc)
return rc;
*mounted = mnt_table_is_fs_mounted(mtab, fs);
if (!mnt_context_switch_ns(cxt, ns_old))
return -MNT_ERR_NAMESPACE;
return 0;
}
static int mnt_context_add_child(struct libmnt_context *cxt, pid_t pid)
{
pid_t *pids;
if (!cxt)
return -EINVAL;
pids = realloc(cxt->children, sizeof(pid_t) * cxt->nchildren + 1);
if (!pids)
return -ENOMEM;
DBG(CXT, ul_debugobj(cxt, "add new child %d", pid));
cxt->children = pids;
cxt->children[cxt->nchildren++] = pid;
return 0;
}
int mnt_fork_context(struct libmnt_context *cxt)
{
int rc = 0;
pid_t pid;
assert(cxt);
if (!mnt_context_is_parent(cxt))
return -EINVAL;
DBG(CXT, ul_debugobj(cxt, "forking context"));
DBG_FLUSH;
pid = fork();
switch (pid) {
case -1: /* error */
DBG(CXT, ul_debugobj(cxt, "fork failed %m"));
return -errno;
case 0: /* child */
cxt->pid = getpid();
mnt_context_enable_fork(cxt, FALSE);
DBG(CXT, ul_debugobj(cxt, "child created"));
break;
default:
rc = mnt_context_add_child(cxt, pid);
break;
}
return rc;
}
int mnt_context_wait_for_children(struct libmnt_context *cxt,
int *nchildren, int *nerrs)
{
int i;
if (!cxt)
return -EINVAL;
assert(mnt_context_is_parent(cxt));
for (i = 0; i < cxt->nchildren; i++) {
pid_t pid = cxt->children[i];
int rc = 0, ret = 0;
if (!pid)
continue;
do {
DBG(CXT, ul_debugobj(cxt,
"waiting for child (%d/%d): %d",
i + 1, cxt->nchildren, pid));
errno = 0;
rc = waitpid(pid, &ret, 0);
} while (rc == -1 && errno == EINTR);
if (nchildren)
(*nchildren)++;
if (rc != -1 && nerrs) {
if (WIFEXITED(ret))
(*nerrs) += WEXITSTATUS(ret) == 0 ? 0 : 1;
else
(*nerrs)++;
}
cxt->children[i] = 0;
}
cxt->nchildren = 0;
free(cxt->children);
cxt->children = NULL;
return 0;
}
static void close_ns(struct libmnt_ns *ns)
{
if (ns->fd == -1)
return;
close(ns->fd);
ns->fd = -1;
mnt_unref_cache(ns->cache);
ns->cache = NULL;
}
/**
* mnt_context_set_target_ns:
* @cxt: mount context
* @path: path to target namespace or NULL
*
* Sets target namespace to namespace represented by @path. If @path is NULL,
* target namespace is cleared.
*
* Returns: 0 on success, negative number in case of error.
*
* Since: 2.33
*/
int mnt_context_set_target_ns(struct libmnt_context *cxt, const char *path)
{
int errsv = 0;
int tmp;
if (!cxt)
return -EINVAL;
DBG(CXT, ul_debugobj(cxt, "Setting %s as target namespace", path));
/* cleanup only */
if (!path) {
close_ns(&cxt->ns_orig);
close_ns(&cxt->ns_tgt);
return 0;
}
errno = 0;
/* open original namespace */
if (cxt->ns_orig.fd == -1) {
cxt->ns_orig.fd = open("/proc/self/ns/mnt", O_RDONLY | O_CLOEXEC);
if (cxt->ns_orig.fd == -1)
return -errno;
cxt->ns_orig.cache = NULL;
}
/* open target (wanted) namespace */
tmp = open(path, O_RDONLY | O_CLOEXEC);
if (tmp == -1)
return -errno;
/* test whether namespace switching works */
DBG(CXT, ul_debugobj(cxt, "Trying whether namespace is valid"));
if (setns(tmp, CLONE_NEWNS)
|| setns(cxt->ns_orig.fd, CLONE_NEWNS)) {
errsv = errno;
DBG(CXT, ul_debugobj(cxt, "setns(2) failed [errno=%d %m]", errno));
goto err;
}
close_ns(&cxt->ns_tgt);
cxt->ns_tgt.fd = tmp;
cxt->ns_tgt.cache = NULL;
return 0;
err:
close(tmp);
errno = errsv;
return -errno;
}
/**
* mnt_context_get_target_ns:
* @cxt: mount context
*
* Returns: pointer to target namespace
*
* Since: 2.33
*/
struct libmnt_ns *mnt_context_get_target_ns(struct libmnt_context *cxt)
{
return &cxt->ns_tgt;
}
/**
* mnt_context_get_origin_ns:
* @cxt: mount context
*
* Returns: pointer to original namespace
*
* Since: 2.33
*/
struct libmnt_ns *mnt_context_get_origin_ns(struct libmnt_context *cxt)
{
return &cxt->ns_orig;
}
/**
* mnt_context_switch_ns:
* @cxt: mount context
* @ns: namespace to switch to
*
* Switch to namespace specified by ns
*
* Typical usage:
* <informalexample>
* <programlisting>
* 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);
* </programlisting>
* </informalexample>
*
* Returns: pointer to previous namespace or NULL on error
*
* Since: 2.33
*/
struct libmnt_ns *mnt_context_switch_ns(struct libmnt_context *cxt, struct libmnt_ns *ns)
{
struct libmnt_ns *old;
if (!cxt || !ns)
return NULL;
old = cxt->ns_cur;
if (ns == old || ns->fd == -1)
return old;
/* remember the curremt cache */
if (old->cache != cxt->cache) {
mnt_unref_cache(old->cache);
old->cache = cxt->cache;
mnt_ref_cache(old->cache);
}
/* switch */
DBG(CXT, ul_debugobj(cxt, "Switching to %s namespace",
ns == mnt_context_get_target_ns(cxt) ? "target" :
ns == mnt_context_get_origin_ns(cxt) ? "original" : "other"));
if (setns(ns->fd, CLONE_NEWNS)) {
int errsv = errno;
DBG(CXT, ul_debugobj(cxt, "setns(2) failed [errno=%d %m]", errno));
errno = errsv;
return NULL;
}
/* update pointer to the current namespace */
cxt->ns_cur = ns;
/* update pointer to the cache */
mnt_unref_cache(cxt->cache);
cxt->cache = ns->cache;
mnt_ref_cache(cxt->cache);
return old;
}
/**
* mnt_context_switch_origin_ns:
* @cxt: mount context
*
* Switch to original namespace
*
* This is shorthand for
* <informalexample>
* <programlisting>
* mnt_context_switch_ns(cxt, mnt_context_get_origin_ns(cxt));
* </programlisting>
* </informalexample>
*
* Returns: pointer to previous namespace or NULL on error
*
* Since: 2.33
*/
struct libmnt_ns *mnt_context_switch_origin_ns(struct libmnt_context *cxt)
{
return mnt_context_switch_ns(cxt, mnt_context_get_origin_ns(cxt));
}
/**
* mnt_context_switch_target_ns:
* @cxt: mount context
*
* Switch to target namespace
*
* This is shorthand for
* <informalexample>
* <programlisting>
* mnt_context_switch_ns(cxt, mnt_context_get_target_ns(cxt));
* </programlisting>
* </informalexample>
*
* Returns: pointer to previous namespace or NULL on error
*
* Since: 2.33
*/
struct libmnt_ns *mnt_context_switch_target_ns(struct libmnt_context *cxt)
{
return mnt_context_switch_ns(cxt, mnt_context_get_target_ns(cxt));
}
#ifdef TEST_PROGRAM
static struct libmnt_lock *lock;
static void lock_fallback(void)
{
if (lock)
mnt_unlock_file(lock);
}
static int test_mount(struct libmnt_test *ts, int argc, char *argv[])
{
int idx = 1, rc = 0;
struct libmnt_context *cxt;
if (argc < 2)
return -EINVAL;
cxt = mnt_new_context();
if (!cxt)
return -ENOMEM;
if (!strcmp(argv[idx], "-o")) {
mnt_context_set_options(cxt, argv[idx + 1]);
idx += 2;
}
if (!strcmp(argv[idx], "-t")) {
/* TODO: use mnt_context_set_fstype_pattern() */
mnt_context_set_fstype(cxt, argv[idx + 1]);
idx += 2;
}
if (argc == idx + 1)
/* mount <mountpoint>|<device> */
mnt_context_set_target(cxt, argv[idx++]);
else if (argc == idx + 2) {
/* mount <device> <mountpoint> */
mnt_context_set_source(cxt, argv[idx++]);
mnt_context_set_target(cxt, argv[idx++]);
}
/* this is unnecessary! -- libmount is able to internally
* create and manage the lock
*/
lock = mnt_context_get_lock(cxt);
if (lock)
atexit(lock_fallback);
rc = mnt_context_mount(cxt);
if (rc)
warn("failed to mount");
else
printf("successfully mounted\n");
lock = NULL; /* because we use atexit lock_fallback */
mnt_free_context(cxt);
return rc;
}
static int test_umount(struct libmnt_test *ts, int argc, char *argv[])
{
int idx = 1, rc = 0;
struct libmnt_context *cxt;
if (argc < 2)
return -EINVAL;
cxt = mnt_new_context();
if (!cxt)
return -ENOMEM;
if (!strcmp(argv[idx], "-t")) {
mnt_context_set_fstype(cxt, argv[idx + 1]);
idx += 2;
}
if (!strcmp(argv[idx], "-f")) {
mnt_context_enable_force(cxt, TRUE);
idx++;
}
if (!strcmp(argv[idx], "-l")) {
mnt_context_enable_lazy(cxt, TRUE);
idx++;
}
if (!strcmp(argv[idx], "-r")) {
mnt_context_enable_rdonly_umount(cxt, TRUE);
idx++;
}
if (argc == idx + 1) {
/* mount <mountpoint>|<device> */
mnt_context_set_target(cxt, argv[idx++]);
} else {
rc = -EINVAL;
goto err;
}
lock = mnt_context_get_lock(cxt);
if (lock)
atexit(lock_fallback);
rc = mnt_context_umount(cxt);
if (rc)
printf("failed to umount\n");
else
printf("successfully umounted\n");
err:
lock = NULL; /* because we use atexit lock_fallback */
mnt_free_context(cxt);
return rc;
}
static int test_flags(struct libmnt_test *ts, int argc, char *argv[])
{
int idx = 1, rc = 0;
struct libmnt_context *cxt;
const char *opt = NULL;
unsigned long flags = 0;
if (argc < 2)
return -EINVAL;
cxt = mnt_new_context();
if (!cxt)
return -ENOMEM;
if (!strcmp(argv[idx], "-o")) {
mnt_context_set_options(cxt, argv[idx + 1]);
idx += 2;
}
if (argc == idx + 1)
/* mount <mountpoint>|<device> */
mnt_context_set_target(cxt, argv[idx++]);
rc = mnt_context_prepare_mount(cxt);
if (rc)
printf("failed to prepare mount %s\n", strerror(-rc));
opt = mnt_fs_get_options(cxt->fs);
if (opt)
fprintf(stdout, "options: %s\n", opt);
mnt_context_get_mflags(cxt, &flags);
fprintf(stdout, "flags: %08lx\n", flags);
mnt_free_context(cxt);
return rc;
}
static int test_mountall(struct libmnt_test *ts, int argc, char *argv[])
{
struct libmnt_context *cxt;
struct libmnt_iter *itr;
struct libmnt_fs *fs;
int mntrc, ignored, idx = 1;
cxt = mnt_new_context();
itr = mnt_new_iter(MNT_ITER_FORWARD);
if (!cxt || !itr)
return -ENOMEM;
if (argc > 2) {
if (argv[idx] && !strcmp(argv[idx], "-O")) {
mnt_context_set_options_pattern(cxt, argv[idx + 1]);
idx += 2;
}
if (argv[idx] && !strcmp(argv[idx], "-t")) {
mnt_context_set_fstype_pattern(cxt, argv[idx + 1]);
idx += 2;
}
}
while (mnt_context_next_mount(cxt, itr, &fs, &mntrc, &ignored) == 0) {
const char *tgt = mnt_fs_get_target(fs);
if (ignored == 1)
printf("%s: ignored: not match\n", tgt);
else if (ignored == 2)
printf("%s: ignored: already mounted\n", tgt);
else if (!mnt_context_get_status(cxt)) {
if (mntrc > 0) {
errno = mntrc;
warn("%s: mount failed", tgt);
} else
warnx("%s: mount failed", tgt);
} else
printf("%s: successfully mounted\n", tgt);
}
mnt_free_context(cxt);
return 0;
}
int main(int argc, char *argv[])
{
struct libmnt_test tss[] = {
{ "--mount", test_mount, "[-o <opts>] [-t <type>] <spec>|<src> <target>" },
{ "--umount", test_umount, "[-t <type>] [-f][-l][-r] <src>|<target>" },
{ "--mount-all", test_mountall, "[-O <pattern>] [-t <pattern] mount all filesystems from fstab" },
{ "--flags", test_flags, "[-o <opts>] <spec>" },
{ NULL }};
umask(S_IWGRP|S_IWOTH); /* to be compatible with mount(8) */
return mnt_run_test(tss, argc, argv);
}
#endif /* TEST_PROGRAM */