Adding upstream version 2.39.3.upstream/2.39.3

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1866 insertions, 0 deletions

diff --git a/libmount/src/context_mount.c b/libmount/src/context_mount.c
new file mode 100644
index 0000000..41986e7
--- /dev/null
+++ b/libmount/src/context_mount.c
@@ -0,0 +1,1866 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * This file is part of libmount from util-linux project.
+ *
+ * Copyright (C) 2010-2018 Karel Zak <kzak@redhat.com>
+ *
+ * libmount is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ */
+
+/**
+ * SECTION: context-mount
+ * @title: Mount context
+ * @short_description: high-level API to mount operation.
+ */
+#include <sys/wait.h>
+#include <sys/mount.h>
+
+#include "mountP.h"
+#include "strutils.h"
+
+#if defined(HAVE_SMACK)
+static int is_option(const char *name, const char *const *names)
+{
+	const char *const *p;
+
+	for (p = names; p && *p; p++) {
+		if (strcmp(name, *p) == 0)
+			return 1;
+	}
+	return 0;
+}
+#endif /* HAVE_SMACK */
+
+/*
+ * this has to be called after mnt_context_evaluate_permissions()
+ */
+static int fix_optstr(struct libmnt_context *cxt)
+{
+	struct libmnt_optlist *ol;
+	struct libmnt_opt *opt;
+	struct libmnt_ns *ns_old;
+	const char *val;
+	int rc = 0;
+
+	assert(cxt);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+	if (cxt->flags & MNT_FL_MOUNTOPTS_FIXED)
+		return 0;
+
+	DBG(CXT, ul_debugobj(cxt, "--> preparing options"));
+
+	ol = mnt_context_get_optlist(cxt);
+	if (!ol)
+		return -EINVAL;
+
+	ns_old = mnt_context_switch_origin_ns(cxt);
+	if (!ns_old)
+		return -MNT_ERR_NAMESPACE;
+
+	/* Fix user (convert "user" to "user=username") */
+	if (mnt_context_is_restricted(cxt)) {
+		opt = mnt_optlist_get_opt(ol, MNT_MS_USER, cxt->map_userspace);
+		if (opt) {
+			char *name = mnt_get_username(getuid());
+
+			if (!name)
+				rc = -ENOMEM;
+			else {
+				rc = mnt_opt_set_value(opt, name);
+				free(name);
+			}
+			if (rc)
+				goto done;
+		}
+	}
+
+	/* Fix UID */
+	opt = mnt_optlist_get_named(ol, "uid", NULL);
+	if (opt && (val = mnt_opt_get_value(opt)) && !isdigit_string(val)) {
+		uid_t id;
+
+		if (strcmp(val, "useruid") == 0)	/* UID of the current user */
+			id = getuid();
+		else
+			rc = mnt_get_uid(val, &id);	/* UID for the username */
+		if (!rc)
+			rc = mnt_opt_set_u64value(opt, id);
+		if (rc)
+			goto done;
+	}
+
+	/* Fix GID */
+	opt = mnt_optlist_get_named(ol, "gid", NULL);
+	if (opt && (val = mnt_opt_get_value(opt)) && !isdigit_string(val)) {
+		gid_t id;
+
+		if (strcmp(val, "usergid") == 0)	/* UID of the current user */
+			id = getgid();
+		else
+			rc = mnt_get_gid(val, &id);	/* UID for the groupname */
+		if (!rc)
+			rc = mnt_opt_set_u64value(opt, id);
+		if (rc)
+			goto done;
+	}
+
+	if (!mnt_context_switch_ns(cxt, ns_old))
+		return -MNT_ERR_NAMESPACE;
+
+#ifdef HAVE_SMACK
+	/* Fix Smack */
+	if (access("/sys/fs/smackfs", F_OK) != 0) {
+		struct libmnt_iter itr;
+
+		static const char *const smack_options[] = {
+			"smackfsdef",
+			"smackfsfloor",
+			"smackfshat",
+			"smackfsroot",
+			"smackfstransmute",
+			NULL,
+		};
+		mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+
+		while (mnt_optlist_next_opt(ol, &itr, &opt) == 0) {
+			if (!is_option(mnt_opt_get_name(opt), smack_options))
+				continue;
+			rc = mnt_optlist_remove_opt(ol, opt);
+			if (rc)
+				goto done;
+		}
+	}
+#endif
+	rc = mnt_context_call_hooks(cxt, MNT_STAGE_PREP_OPTIONS);
+done:
+	DBG(CXT, ul_debugobj(cxt, "<-- preparing options done [rc=%d]", rc));
+	cxt->flags |= MNT_FL_MOUNTOPTS_FIXED;
+
+	if (rc)
+		rc = -MNT_ERR_MOUNTOPT;
+	return rc;
+}
+
+/*
+ * this has to be called before fix_optstr()
+ *
+ * Note that user=<name> may be used by some filesystems as a filesystem
+ * specific option (e.g. cifs). Yes, developers of such filesystems have
+ * allocated pretty hot place in hell...
+ */
+static int evaluate_permissions(struct libmnt_context *cxt)
+{
+	struct libmnt_optlist *ol;
+	struct libmnt_opt *opt = NULL;
+
+	unsigned long user_flags = 0;	/* userspace mount flags */
+	int rc;
+
+	assert(cxt);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+	if (!cxt->fs)
+		return 0;
+
+	DBG(CXT, ul_debugobj(cxt, "mount: evaluating permissions"));
+
+	ol = mnt_context_get_optlist(cxt);
+	if (!ol)
+		return -EINVAL;
+
+	/* get userspace mount flags (user[=<name>] etc.*/
+	rc = mnt_optlist_get_flags(ol, &user_flags, cxt->map_userspace, 0);
+	if (rc)
+		return rc;
+
+	/*
+	* Ignore user=<name> (if <name> is set). Let's keep it hidden
+	* for normal library operations, but visible for /sbin/mount.<type>
+	* helpers.
+	*/
+	if (user_flags & MNT_MS_USER
+	    && (opt = mnt_optlist_get_opt(ol, MNT_MS_USER, cxt->map_userspace))
+	    && mnt_opt_has_value(opt)) {
+		DBG(CXT, ul_debugobj(cxt, "perms: user=<name> detected, ignore"));
+
+		cxt->flags |= MNT_FL_SAVED_USER;
+
+		mnt_opt_set_external(opt, 1);
+		user_flags &= ~MNT_MS_USER;
+	}
+
+	if (!mnt_context_is_restricted(cxt)) {
+		/*
+		 * superuser mount
+		 *
+		 * Let's convert user, users, owenr and groups to MS_* flags
+		 * to be compatible with non-root execution.
+		 *
+		 * The old deprecated way is to use mnt_optstr_get_flags().
+		 */
+		if (user_flags & (MNT_MS_OWNER | MNT_MS_GROUP))
+			rc = mnt_optlist_remove_flags(ol,
+					MNT_MS_OWNER | MNT_MS_GROUP, cxt->map_userspace);
+
+		if (!rc && (user_flags & MNT_MS_OWNER))
+			rc = mnt_optlist_insert_flags(ol,
+					MS_OWNERSECURE, cxt->map_linux,
+					MNT_MS_OWNER, cxt->map_userspace);
+
+		if (!rc && (user_flags & MNT_MS_GROUP))
+			rc = mnt_optlist_insert_flags(ol,
+					MS_OWNERSECURE, cxt->map_linux,
+					MNT_MS_GROUP, cxt->map_userspace);
+
+		if (!rc && (user_flags & MNT_MS_USER)
+		    && (opt = mnt_optlist_get_opt(ol, MNT_MS_USER, cxt->map_userspace))
+		    && !mnt_opt_has_value(opt))
+			rc = mnt_optlist_insert_flags(ol, MS_SECURE, cxt->map_linux,
+					MNT_MS_USER, cxt->map_userspace);
+
+		if (!rc && (user_flags & MNT_MS_USERS))
+			rc = mnt_optlist_insert_flags(ol, MS_SECURE, cxt->map_linux,
+					MNT_MS_USERS, cxt->map_userspace);
+
+		DBG(CXT, ul_debugobj(cxt, "perms: superuser [rc=%d]", rc));
+		if (rc)
+			return rc;
+
+		if (user_flags & (MNT_MS_OWNER | MNT_MS_GROUP |
+				  MNT_MS_USER | MNT_MS_USERS))
+			mnt_optlist_merge_opts(ol);
+	} else {
+
+		/*
+		 * user mount
+		 */
+		if (!mnt_context_tab_applied(cxt))
+		{
+			DBG(CXT, ul_debugobj(cxt, "perms: fstab not applied, ignore user mount"));
+			return -EPERM;
+		}
+
+		/*
+		 * Insert MS_SECURE between system flags on position where is MNT_MS_USER
+		 */
+		if ((user_flags & MNT_MS_USER)
+		    && (rc = mnt_optlist_insert_flags(ol, MS_SECURE, cxt->map_linux,
+						    MNT_MS_USER, cxt->map_userspace)))
+			return rc;
+
+		if ((user_flags & MNT_MS_USERS)
+		    && (rc = mnt_optlist_insert_flags(ol, MS_SECURE, cxt->map_linux,
+						    MNT_MS_USERS, cxt->map_userspace)))
+			return rc;
+
+		/*
+		 * MS_OWNER: Allow owners to mount when fstab contains the
+		 * owner option.  Note that this should never be used in a high
+		 * security environment, but may be useful to give people at
+		 * the console the possibility of mounting a floppy.  MS_GROUP:
+		 * Allow members of device group to mount. (Martin Dickopp)
+		 */
+		if (user_flags & (MNT_MS_OWNER | MNT_MS_GROUP)) {
+			struct stat sb;
+			struct libmnt_cache *cache = NULL;
+			char *xsrc = NULL;
+			const char *srcpath = mnt_fs_get_srcpath(cxt->fs);
+
+			DBG(CXT, ul_debugobj(cxt, "perms: owner/group"));
+
+			if (!srcpath) {					/* Ah... source is TAG */
+				cache = mnt_context_get_cache(cxt);
+				xsrc = mnt_resolve_spec(
+						mnt_context_get_source(cxt),
+						cache);
+				srcpath = xsrc;
+			}
+			if (!srcpath) {
+				DBG(CXT, ul_debugobj(cxt, "perms: src undefined"));
+				return -EPERM;
+			}
+
+			if (strncmp(srcpath, "/dev/", 5) == 0 &&
+			    stat(srcpath, &sb) == 0 &&
+			    (((user_flags & MNT_MS_OWNER) && getuid() == sb.st_uid) ||
+			     ((user_flags & MNT_MS_GROUP) && mnt_in_group(sb.st_gid)))) {
+
+				/* insert MS_OWNERSECURE between system flags */
+				if (user_flags & MNT_MS_OWNER)
+					mnt_optlist_insert_flags(ol,
+							MS_OWNERSECURE, cxt->map_linux,
+							MNT_MS_OWNER, cxt->map_userspace);
+				if (user_flags & MNT_MS_GROUP)
+					mnt_optlist_insert_flags(ol,
+							MS_OWNERSECURE, cxt->map_linux,
+							MNT_MS_GROUP, cxt->map_userspace);
+
+				/* continue as like "user" was specified */
+				user_flags |= MNT_MS_USER;
+				mnt_optlist_append_flags(ol, MNT_MS_USER, cxt->map_userspace);
+			}
+
+			if (!cache)
+				free(xsrc);
+		}
+
+		if (!(user_flags & (MNT_MS_USER | MNT_MS_USERS))) {
+			DBG(CXT, ul_debugobj(cxt, "perms: evaluation ends with -EPERMS [flags=0x%08lx]", user_flags));
+			return -EPERM;
+		}
+
+		/* we have modified some flags (noexec, ...), let's cleanup the
+		 * options to remove duplicate stuff etc.*/
+		mnt_optlist_merge_opts(ol);
+	}
+
+	return 0;
+}
+
+/*
+ * mnt_context_helper_setopt() backend
+ *
+ * This function applies the 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_mount_setopt(struct libmnt_context *cxt, int c, char *arg)
+{
+	int rc = -EINVAL;
+
+	assert(cxt);
+	assert(cxt->action == MNT_ACT_MOUNT);
+
+	switch(c) {
+	case 'f':
+		rc = mnt_context_enable_fake(cxt, TRUE);
+		break;
+	case 'n':
+		rc = mnt_context_disable_mtab(cxt, TRUE);
+		break;
+	case 'r':
+		rc = mnt_context_append_options(cxt, "ro");
+		break;
+	case 'v':
+		rc = mnt_context_enable_verbose(cxt, TRUE);
+		break;
+	case 'w':
+		rc = mnt_context_append_options(cxt, "rw");
+		break;
+	case 'o':
+		if (arg)
+			rc = mnt_context_append_options(cxt, arg);
+		break;
+	case 's':
+		rc = mnt_context_enable_sloppy(cxt, TRUE);
+		break;
+	case 't':
+		if (arg)
+			rc = mnt_context_set_fstype(cxt, arg);
+		break;
+	case 'N':
+		if (arg)
+			rc = mnt_context_set_target_ns(cxt, arg);
+		break;
+	default:
+		return 1;
+	}
+
+	return rc;
+}
+
+static int exec_helper(struct libmnt_context *cxt)
+{
+	struct libmnt_ns *ns_tgt = mnt_context_get_target_ns(cxt);
+	char *namespace = NULL;
+	int rc;
+	pid_t pid;
+
+	assert(cxt);
+	assert(cxt->fs);
+	assert(cxt->helper);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+	DBG(CXT, ul_debugobj(cxt, "mount: executing helper %s", cxt->helper));
+
+	if (ns_tgt->fd != -1
+	    && asprintf(&namespace, "/proc/%i/fd/%i",
+			getpid(), ns_tgt->fd) == -1) {
+		return -ENOMEM;
+	}
+
+	DBG_FLUSH;
+
+	pid = fork();
+	switch (pid) {
+	case 0:
+	{
+		const char *args[14], *type;
+		struct libmnt_optlist *ol = mnt_context_get_optlist(cxt);
+		struct libmnt_opt *opt;
+		const char *o = NULL;
+		int i = 0;
+
+		if (!ol)
+			_exit(EXIT_FAILURE);
+
+		/* Call helper with original user=<name> (aka "saved user")
+		 * or remove the username at all.
+		 */
+		opt = mnt_optlist_get_opt(ol, MNT_MS_USER, cxt->map_userspace);
+		if (opt && !(cxt->flags & MNT_FL_SAVED_USER))
+			mnt_opt_set_value(opt, NULL);
+
+		if (mnt_optlist_get_optstr(ol, &o, NULL, MNT_OL_FLTR_HELPERS))
+			_exit(EXIT_FAILURE);
+
+		if (drop_permissions() != 0)
+			_exit(EXIT_FAILURE);
+
+		if (!mnt_context_switch_origin_ns(cxt))
+			_exit(EXIT_FAILURE);
+
+		type = mnt_fs_get_fstype(cxt->fs);
+
+		args[i++] = cxt->helper;		/* 1 */
+		args[i++] = mnt_fs_get_srcpath(cxt->fs);/* 2 */
+		args[i++] = mnt_fs_get_target(cxt->fs);	/* 3 */
+
+		if (mnt_context_is_sloppy(cxt))
+			args[i++] = "-s";		/* 4 */
+		if (mnt_context_is_fake(cxt))
+			args[i++] = "-f";		/* 5 */
+		if (mnt_context_is_nomtab(cxt))
+			args[i++] = "-n";		/* 6 */
+		if (mnt_context_is_verbose(cxt))
+			args[i++] = "-v";		/* 7 */
+		if (o) {
+			args[i++] = "-o";		/* 8 */
+			args[i++] = o;			/* 9 */
+		}
+		if (type
+		    && strchr(type, '.')
+		    && !endswith(cxt->helper, type)) {
+			args[i++] = "-t";		/* 10 */
+			args[i++] = type;		/* 11 */
+		}
+		if (namespace) {
+			args[i++] = "-N";		/* 11 */
+			args[i++] = namespace;		/* 12 */
+		}
+		args[i] = NULL;				/* 13 */
+		for (i = 0; args[i]; i++)
+			DBG(CXT, ul_debugobj(cxt, "argv[%d] = \"%s\"",
+							i, args[i]));
+		DBG_FLUSH;
+		execv(cxt->helper, (char * const *) args);
+		_exit(EXIT_FAILURE);
+	}
+	default:
+	{
+		int st;
+
+		if (waitpid(pid, &st, 0) == (pid_t) -1) {
+			cxt->helper_status = -1;
+			rc = -errno;
+		} else {
+			cxt->helper_status = WIFEXITED(st) ? WEXITSTATUS(st) : -1;
+			cxt->helper_exec_status = rc = 0;
+		}
+		DBG(CXT, ul_debugobj(cxt, "%s executed [status=%d, rc=%d%s]",
+				cxt->helper,
+				cxt->helper_status, rc,
+				rc ? " waitpid failed" : ""));
+		break;
+	}
+
+	case -1:
+		cxt->helper_exec_status = rc = -errno;
+		DBG(CXT, ul_debugobj(cxt, "fork() failed"));
+		break;
+	}
+
+	free(namespace);
+	return rc;
+}
+
+/*
+ * The default is to use fstype from cxt->fs, this could be overwritten by
+ * @try_type argument. If @try_type is specified then mount with MS_SILENT.
+ *
+ * Returns: 0 on success,
+ *         >0 in case of mount(2) error (returns syscall errno),
+ *         <0 in case of other errors.
+ */
+static int do_mount(struct libmnt_context *cxt, const char *try_type)
+{
+	int rc = 0;
+	char *org_type = NULL;
+	struct libmnt_optlist *ol = NULL;
+
+	assert(cxt);
+	assert(cxt->fs);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+	mnt_context_reset_status(cxt);
+
+	if (try_type) {
+		rc = mnt_context_prepare_helper(cxt, "mount", try_type);
+		if (rc)
+			return rc;
+	}
+
+	if (cxt->helper)
+		return exec_helper(cxt);
+
+	if (try_type) {
+		ol = mnt_context_get_optlist(cxt);
+		assert(ol);
+
+		mnt_optlist_append_flags(ol, MS_SILENT, cxt->map_linux);
+		if (mnt_fs_get_fstype(cxt->fs)) {
+			org_type = strdup(mnt_fs_get_fstype(cxt->fs));
+			if (!org_type) {
+				rc = -ENOMEM;
+				goto done;
+			}
+		}
+		mnt_fs_set_fstype(cxt->fs, try_type);
+	}
+
+
+	/*
+	 * mount(2) or others syscalls
+	 */
+	if (!rc)
+		rc = mnt_context_call_hooks(cxt, MNT_STAGE_MOUNT);
+
+	if (rc == 0 && mnt_context_is_fake(cxt)) {
+		DBG(CXT, ul_debugobj(cxt, "FAKE (-f) set status=0"));
+		cxt->syscall_status = 0;
+	}
+
+	if (org_type && rc != 0)
+		__mnt_fs_set_fstype_ptr(cxt->fs, org_type);
+	org_type  = NULL;
+
+	if (rc == 0 && try_type && cxt->update) {
+		struct libmnt_fs *fs = mnt_update_get_fs(cxt->update);
+		if (fs)
+			rc = mnt_fs_set_fstype(fs, try_type);
+	}
+
+done:
+	if (try_type && ol)
+		mnt_optlist_remove_flags(ol, MS_SILENT, cxt->map_linux);
+	free(org_type);
+	return rc;
+}
+
+static int is_success_status(struct libmnt_context *cxt)
+{
+	if (mnt_context_helper_executed(cxt))
+		return mnt_context_get_helper_status(cxt) == 0;
+
+	if (mnt_context_syscall_called(cxt))
+		return mnt_context_get_status(cxt) == 1;
+
+	return 0;
+}
+
+/* try mount(2) for all items in comma separated list of the filesystem @types */
+static int do_mount_by_types(struct libmnt_context *cxt, const char *types)
+{
+	int rc = -EINVAL;
+	char *p, *p0;
+
+	assert(cxt);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+	DBG(CXT, ul_debugobj(cxt, "trying to mount by FS list '%s'", types));
+
+	p0 = p = strdup(types);
+	if (!p)
+		return -ENOMEM;
+	do {
+		char *autotype = NULL;
+		char *end = strchr(p, ',');
+
+		if (end)
+			*end = '\0';
+
+		DBG(CXT, ul_debugobj(cxt, "-->trying '%s'", p));
+
+		/* Let's support things like "udf,iso9660,auto" */
+		if (strcmp(p, "auto") == 0) {
+			rc = mnt_context_guess_srcpath_fstype(cxt, &autotype);
+			if (rc) {
+				DBG(CXT, ul_debugobj(cxt, "failed to guess FS type [rc=%d]", rc));
+				free(p0);
+				free(autotype);
+				return rc;
+			}
+			p = autotype;
+			DBG(CXT, ul_debugobj(cxt, "   --> '%s'", p));
+		}
+
+		if (p)
+			rc = do_mount(cxt, p);
+		p = end ? end + 1 : NULL;
+		free(autotype);
+	} while (!is_success_status(cxt) && p);
+
+	free(p0);
+	return rc;
+}
+
+
+static int do_mount_by_pattern(struct libmnt_context *cxt, const char *pattern)
+{
+	int neg = pattern && strncmp(pattern, "no", 2) == 0;
+	int rc = -EINVAL;
+	char **filesystems, **fp;
+	struct libmnt_ns *ns_old;
+
+	assert(cxt);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+	/*
+	 * Use the pattern as list of the filesystems
+	 */
+	if (!neg && pattern) {
+		DBG(CXT, ul_debugobj(cxt, "use FS pattern as FS list"));
+		return do_mount_by_types(cxt, pattern);
+	}
+
+	DBG(CXT, ul_debugobj(cxt, "trying to mount by FS pattern '%s'", pattern));
+
+	/*
+	 * Apply pattern to /etc/filesystems and /proc/filesystems
+	 */
+	ns_old = mnt_context_switch_origin_ns(cxt);
+	if (!ns_old)
+		return -MNT_ERR_NAMESPACE;
+	rc = mnt_get_filesystems(&filesystems, neg ? pattern : NULL);
+	if (!mnt_context_switch_ns(cxt, ns_old))
+		return -MNT_ERR_NAMESPACE;
+	if (rc)
+		return rc;
+
+	if (filesystems == NULL)
+		return -MNT_ERR_NOFSTYPE;
+
+	for (fp = filesystems; *fp; fp++) {
+		DBG(CXT, ul_debugobj(cxt, " ##### trying '%s'", *fp));
+		rc = do_mount(cxt, *fp);
+		if (is_success_status(cxt))
+			break;
+		if (mnt_context_get_syscall_errno(cxt) != EINVAL &&
+		    mnt_context_get_syscall_errno(cxt) != ENODEV)
+			break;
+	}
+	mnt_free_filesystems(filesystems);
+	return rc;
+}
+
+static int prepare_target(struct libmnt_context *cxt)
+{
+	const char *tgt, *prefix;
+	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;
+
+	/* apply prefix */
+	prefix = mnt_context_get_target_prefix(cxt);
+	if (prefix) {
+		const char *p = *tgt == '/' ? tgt + 1 : tgt;
+
+		if (!*p)
+			/* target is "/", use "/prefix" */
+			rc = mnt_fs_set_target(cxt->fs, prefix);
+		else {
+			char *path = NULL;
+
+			if (asprintf(&path, "%s/%s", prefix, p) <= 0)
+				rc = -ENOMEM;
+			else {
+				rc = mnt_fs_set_target(cxt->fs, path);
+				free(path);
+			}
+		}
+		if (rc)
+			return rc;
+		tgt = mnt_fs_get_target(cxt->fs);
+	}
+
+	ns_old = mnt_context_switch_target_ns(cxt);
+	if (!ns_old)
+		return -MNT_ERR_NAMESPACE;
+
+	/* canonicalize the path */
+	if (rc == 0) {
+		struct libmnt_cache *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 (rc == 0)
+		rc = mnt_context_call_hooks(cxt, MNT_STAGE_PREP_TARGET);
+
+	if (!mnt_context_switch_ns(cxt, ns_old))
+		return -MNT_ERR_NAMESPACE;
+
+	DBG(CXT, ul_debugobj(cxt, "final target '%s' [rc=%d]",
+				mnt_fs_get_target(cxt->fs), rc));
+	return rc;
+}
+
+/**
+ * mnt_context_prepare_mount:
+ * @cxt: context
+ *
+ * Prepare context for mounting, unnecessary for mnt_context_mount().
+ *
+ * Returns: negative number on error, zero on success
+ */
+int mnt_context_prepare_mount(struct libmnt_context *cxt)
+{
+	int rc = -EINVAL;
+	struct libmnt_ns *ns_old;
+
+	if (!cxt || !cxt->fs || mnt_fs_is_swaparea(cxt->fs))
+		return -EINVAL;
+	if (!mnt_fs_get_source(cxt->fs) && !mnt_fs_get_target(cxt->fs))
+		return -EINVAL;
+	if (cxt->flags & MNT_FL_PREPARED)
+		return 0;
+
+	assert(cxt->helper_exec_status == 1);
+	assert(cxt->syscall_status == 1);
+
+	cxt->action = MNT_ACT_MOUNT;
+
+	ns_old = mnt_context_switch_target_ns(cxt);
+	if (!ns_old)
+		return -MNT_ERR_NAMESPACE;
+
+	DBG(CXT, ul_debugobj(cxt, "mount: preparing"));
+
+	rc = mnt_context_apply_fstab(cxt);
+	if (!rc)
+		rc = mnt_context_merge_mflags(cxt);
+	if (!rc && cxt->fs && cxt->optlist)
+		rc = mnt_fs_follow_optlist(cxt->fs, cxt->optlist);
+	if (!rc)
+		rc = evaluate_permissions(cxt);
+	if (!rc)
+		rc = fix_optstr(cxt);
+	if (!rc)
+		rc = mnt_context_prepare_srcpath(cxt);
+	if (!rc)
+		rc = mnt_context_guess_fstype(cxt);
+	if (!rc)
+		rc = prepare_target(cxt);
+	if (!rc)
+		rc = mnt_context_prepare_helper(cxt, "mount", NULL);
+
+	if (!rc && mnt_context_is_onlyonce(cxt)) {
+		int mounted = 0;
+		rc = mnt_context_is_fs_mounted(cxt, cxt->fs, &mounted);
+		if (rc == 0 && mounted == 1) {
+			rc = -MNT_ERR_ONLYONCE;
+			goto end;
+		}
+	}
+
+	if (!rc)
+		rc = mnt_context_call_hooks(cxt, MNT_STAGE_PREP);
+
+	if (rc) {
+		DBG(CXT, ul_debugobj(cxt, "mount: preparing failed"));
+		goto end;
+	}
+
+	cxt->flags |= MNT_FL_PREPARED;
+
+end:
+	if (!mnt_context_switch_ns(cxt, ns_old))
+		return -MNT_ERR_NAMESPACE;
+
+	return rc;
+}
+
+/**
+ * mnt_context_do_mount
+ * @cxt: context
+ *
+ * Call mount(2) or mount.type helper. Unnecessary for mnt_context_mount().
+ *
+ * Note that this function could be called only once. If you want to mount
+ * another source or target, then you have to call mnt_reset_context().
+ *
+ * If you want to call mount(2) for the same source and target with different
+ * mount flags or fstype, then call mnt_context_reset_status() and then try
+ * again mnt_context_do_mount().
+ *
+ * WARNING: non-zero return code does not mean that mount(2) syscall or
+ *          mount.type helper wasn't successfully called.
+ *
+ * Check mnt_context_get_status() after error! See mnt_context_mount() for more
+ * details about errors and warnings.
+ *
+ * Returns: 0 on success;
+ *         >0 in case of mount(2) error (returns syscall errno),
+ *         <0 in case of other errors.
+ */
+int mnt_context_do_mount(struct libmnt_context *cxt)
+{
+	const char *type;
+	int res = 0, rc = 0;
+	struct libmnt_ns *ns_old;
+
+	assert(cxt);
+	assert(cxt->fs);
+	assert(cxt->helper_exec_status == 1);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+	assert((cxt->flags & MNT_FL_PREPARED));
+	assert((cxt->action == MNT_ACT_MOUNT));
+
+	DBG(CXT, ul_debugobj(cxt, "mount: do mount"));
+
+	ns_old = mnt_context_switch_target_ns(cxt);
+	if (!ns_old)
+		return -MNT_ERR_NAMESPACE;
+
+	/* before mount stage */
+	rc = mnt_context_call_hooks(cxt, MNT_STAGE_MOUNT_PRE);
+	if (rc)
+		return rc;
+
+	/* mount stage */
+	type = mnt_fs_get_fstype(cxt->fs);
+	if (type) {
+		if (strchr(type, ','))
+			/* this only happens if fstab contains a list of filesystems */
+			res = do_mount_by_types(cxt, type);
+		else
+			res = do_mount(cxt, NULL);
+	} else
+		res = do_mount_by_pattern(cxt, cxt->fstype_pattern);
+
+	/* after mount stage */
+	if (res == 0) {
+		rc = mnt_context_call_hooks(cxt, MNT_STAGE_MOUNT_POST);
+		if (rc)
+			return rc;
+	}
+
+	if (!mnt_context_switch_ns(cxt, ns_old))
+		return -MNT_ERR_NAMESPACE;
+
+	DBG(CXT, ul_debugobj(cxt, "mnt_context_do_mount() done [rc=%d]", res));
+	return res;
+}
+
+/*
+ * Returns mountinfo FS entry of context source patch if the source is already
+ * mounted. This function is used for "already mounted" message or to get FS of
+ * re-used loop device.
+ */
+static struct libmnt_fs *get_already_mounted_source(struct libmnt_context *cxt)
+{
+	const char *src;
+	struct libmnt_table *tb;
+
+	assert(cxt);
+
+	src = mnt_fs_get_srcpath(cxt->fs);
+
+	if (src && mnt_context_get_mountinfo(cxt, &tb) == 0) {
+		struct libmnt_iter itr;
+		struct libmnt_fs *fs;
+
+		mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+		while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+			const char *s = mnt_fs_get_srcpath(fs),
+				   *t = mnt_fs_get_target(fs);
+
+			if (t && s && mnt_fs_streq_srcpath(fs, src))
+				return fs;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * Checks if source filesystem superblock is already ro-mounted. Note that we
+ * care about FS superblock as VFS node is irrelevant here.
+ */
+static int is_source_already_rdonly(struct libmnt_context *cxt)
+{
+	struct libmnt_fs *fs = get_already_mounted_source(cxt);
+	const char *opts = fs ? mnt_fs_get_fs_options(fs) : NULL;
+
+	return opts && mnt_optstr_get_option(opts, "ro", NULL, NULL) == 0;
+}
+
+/**
+ * mnt_context_finalize_mount:
+ * @cxt: context
+ *
+ * Mtab update, etc. Unnecessary for mnt_context_mount(), but should be called
+ * after mnt_context_do_mount(). See also mnt_context_set_syscall_status().
+ *
+ * Returns: negative number on error, 0 on success.
+ */
+int mnt_context_finalize_mount(struct libmnt_context *cxt)
+{
+	int rc;
+
+	assert(cxt);
+	assert(cxt->fs);
+	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+	assert((cxt->flags & MNT_FL_PREPARED));
+
+	rc = mnt_context_prepare_update(cxt);
+	if (!rc)
+		rc = mnt_context_update_tabs(cxt);
+	return rc;
+}
+
+/**
+ * mnt_context_mount:
+ * @cxt: mount context
+ *
+ * High-level, mounts the filesystem by mount(2) or fork()+exec(/sbin/mount.type).
+ *
+ * This is similar to:
+ *
+ *	mnt_context_prepare_mount(cxt);
+ *	mnt_context_do_mount(cxt);
+ *	mnt_context_finalize_mount(cxt);
+ *
+ * See also mnt_context_disable_helpers().
+ *
+ * Note that this function should be called only once. If you want to mount with
+ * different settings, then you have to call mnt_reset_context(). It's NOT enough
+ * to call mnt_context_reset_status(). If you want to call this function more than
+ * once, the whole context has to be reset.
+ *
+ * WARNING: non-zero return code does not mean that mount(2) syscall or
+ *          mount.type helper wasn't successfully called.
+ *
+ * Always use mnt_context_get_status():
+ *
+ * <informalexample>
+ *   <programlisting>
+ *       rc = mnt_context_mount(cxt);
+ *
+ *       if (mnt_context_helper_executed(cxt))
+ *               return mnt_context_get_helper_status(cxt);
+ *       if (rc == 0 && mnt_context_get_status(cxt) == 1)
+ *               return MNT_EX_SUCCESS;
+ *       return MNT_EX_FAIL;
+ *   </programlisting>
+ * </informalexample>
+ *
+ * or mnt_context_get_excode() to generate mount(8) compatible error
+ * or warning message:
+ *
+ * <informalexample>
+ *   <programlisting>
+ *       rc = mnt_context_mount(cxt);
+ *       rc = mnt_context_get_excode(cxt, rc, buf, sizeof(buf));
+ *       if (buf)
+ *               warnx(_("%s: %s"), mnt_context_get_target(cxt), buf);
+ *	 return rc;   // MNT_EX_*
+ *   </programlisting>
+ * </informalexample>
+ *
+ * Returns: 0 on success;
+ *         >0 in case of mount(2) error (returns syscall errno),
+ *         <0 in case of other errors.
+ */
+int mnt_context_mount(struct libmnt_context *cxt)
+{
+	int rc;
+	struct libmnt_ns *ns_old;
+
+	assert(cxt);
+	assert(cxt->fs);
+	assert(cxt->helper_exec_status == 1);
+
+	ns_old = mnt_context_switch_target_ns(cxt);
+	if (!ns_old)
+		return -MNT_ERR_NAMESPACE;
+
+again:
+	rc = mnt_context_prepare_mount(cxt);
+	if (!rc)
+		rc = mnt_context_prepare_update(cxt);
+	if (!rc)
+		rc = mnt_context_do_mount(cxt);
+	if (!rc)
+		rc = mnt_context_update_tabs(cxt);
+
+	/*
+	 * Read-only device or already read-only mounted FS.
+	 * Try mount the filesystem read-only.
+	 */
+	if ((rc == -EROFS && !mnt_context_syscall_called(cxt))	/* before syscall; rdonly loopdev */
+	     || mnt_context_get_syscall_errno(cxt) == EROFS	/* syscall failed with EROFS */
+	     || mnt_context_get_syscall_errno(cxt) == EACCES	/* syscall failed with EACCES */
+	     || (mnt_context_get_syscall_errno(cxt) == EBUSY	/* already ro-mounted FS */
+		 && is_source_already_rdonly(cxt)))
+	{
+		unsigned long mflags = 0;
+
+		mnt_context_get_mflags(cxt, &mflags);
+
+		if (!(mflags & MS_RDONLY)			/* not yet RDONLY */
+		    && !(mflags & MS_REMOUNT)			/* not remount */
+		    && !(mflags & MS_BIND)			/* not bin mount */
+		    && !mnt_context_is_rwonly_mount(cxt)) {	/* no explicit read-write */
+
+			assert(!(cxt->flags & MNT_FL_FORCED_RDONLY));
+			DBG(CXT, ul_debugobj(cxt, "write-protected source, trying RDONLY."));
+
+			mnt_context_reset_status(cxt);
+			mnt_context_set_mflags(cxt, mflags | MS_RDONLY);
+			cxt->flags |= MNT_FL_FORCED_RDONLY;
+			goto again;
+		}
+	}
+
+	if (rc == 0)
+		rc = mnt_context_call_hooks(cxt, MNT_STAGE_POST);
+
+	mnt_context_deinit_hooksets(cxt);
+
+	if (!mnt_context_switch_ns(cxt, ns_old))
+		rc = -MNT_ERR_NAMESPACE;
+
+	DBG(CXT, ul_debugobj(cxt, "mnt_context_mount() done [rc=%d]", rc));
+	return rc;
+}
+
+/**
+ * mnt_context_next_mount:
+ * @cxt: context
+ * @itr: iterator
+ * @fs: returns the current filesystem
+ * @mntrc: returns the return code from mnt_context_mount()
+ * @ignored: returns 1 for non-matching and 2 for already mounted filesystems
+ *
+ * This function tries to mount the next filesystem from fstab (as returned by
+ * mnt_context_get_fstab()). See also mnt_context_set_fstab().
+ *
+ * You can filter out filesystems by:
+ *	mnt_context_set_options_pattern() to simulate mount -a -O pattern
+ *	mnt_context_set_fstype_pattern()  to simulate mount -a -t pattern
+ *
+ * If the filesystem is already mounted or does not match defined criteria,
+ * then the mnt_context_next_mount() function returns zero, but the @ignored is
+ * non-zero. Note that the root filesystem and filesystems with "noauto" option
+ * are always ignored.
+ *
+ * If mount(2) syscall or mount.type helper failed, then the
+ * mnt_context_next_mount() function returns zero, but the @mntrc is non-zero.
+ * Use also mnt_context_get_status() to check if the filesystem was
+ * successfully mounted.
+ *
+ * See mnt_context_mount() for more details about errors and warnings.
+ *
+ * Returns: 0 on success,
+ *         <0 in case of error (!= mount(2) errors)
+ *          1 at the end of the list.
+ */
+int mnt_context_next_mount(struct libmnt_context *cxt,
+			   struct libmnt_iter *itr,
+			   struct libmnt_fs **fs,
+			   int *mntrc,
+			   int *ignored)
+{
+	struct libmnt_table *fstab, *mountinfo;
+	const char *o, *tgt;
+	int rc, mounted = 0;
+
+	if (ignored)
+		*ignored = 0;
+	if (mntrc)
+		*mntrc = 0;
+
+	if (!cxt || !fs || !itr)
+		return -EINVAL;
+
+	/* ingore --onlyonce, it's default behavior for --all */
+	mnt_context_enable_onlyonce(cxt, 0);
+
+	rc = mnt_context_get_fstab(cxt, &fstab);
+	if (rc)
+		return rc;
+
+	rc = mnt_table_next_fs(fstab, itr, fs);
+	if (rc != 0)
+		return rc;	/* more filesystems (or error) */
+
+	o = mnt_fs_get_user_options(*fs);
+	tgt = mnt_fs_get_target(*fs);
+
+	DBG(CXT, ul_debugobj(cxt, "next-mount: trying %s", tgt));
+
+	/*  ignore swap */
+	if (mnt_fs_is_swaparea(*fs) ||
+
+	/* ignore root filesystem */
+	   (tgt && (strcmp(tgt, "/") == 0 || strcmp(tgt, "root") == 0)) ||
+
+	/* ignore noauto filesystems */
+	   (o && mnt_optstr_get_option(o, "noauto", NULL, NULL) == 0) ||
+
+	/* ignore filesystems which don't match options patterns */
+	   (cxt->fstype_pattern && !mnt_fs_match_fstype(*fs,
+					cxt->fstype_pattern)) ||
+
+	/* ignore filesystems which don't match type patterns */
+	   (cxt->optstr_pattern && !mnt_fs_match_options(*fs,
+					cxt->optstr_pattern))) {
+		if (ignored)
+			*ignored = 1;
+		DBG(CXT, ul_debugobj(cxt, "next-mount: not-match "
+				"[fstype: %s, t-pattern: %s, options: %s, O-pattern: %s]",
+				mnt_fs_get_fstype(*fs),
+				cxt->fstype_pattern,
+				mnt_fs_get_options(*fs),
+				cxt->optstr_pattern));
+		return 0;
+	}
+
+	/* ignore already mounted filesystems */
+	rc = mnt_context_is_fs_mounted(cxt, *fs, &mounted);
+	if (rc) {
+		if (mnt_table_is_empty(cxt->mountinfo)) {
+			DBG(CXT, ul_debugobj(cxt, "next-mount: no mount table [rc=%d], ignore", rc));
+			rc = 0;
+			if (ignored)
+				*ignored = 1;
+		}
+		return rc;
+	}
+	if (mounted) {
+		if (ignored)
+			*ignored = 2;
+		return 0;
+	}
+
+	/* Save mount options, etc. -- this is effective for the first
+	 * mnt_context_next_mount() call only. Make sure that cxt has not set
+	 * source, target or fstype.
+	 */
+	if (!mnt_context_has_template(cxt)) {
+		mnt_context_set_source(cxt, NULL);
+		mnt_context_set_target(cxt, NULL);
+		mnt_context_set_fstype(cxt, NULL);
+		mnt_context_save_template(cxt);
+	}
+
+	/* reset context, but protect mountinfo */
+	mountinfo = cxt->mountinfo;
+	cxt->mountinfo = NULL;
+	mnt_reset_context(cxt);
+	cxt->mountinfo = mountinfo;
+
+	if (mnt_context_is_fork(cxt)) {
+		rc = mnt_fork_context(cxt);
+		if (rc)
+			return rc;		/* fork error */
+
+		if (mnt_context_is_parent(cxt)) {
+			return 0;		/* parent */
+		}
+	}
+
+	/*
+	 * child or non-forked
+	 */
+
+	/* copy stuff from fstab to context */
+	rc = mnt_context_apply_fs(cxt, *fs);
+	if (!rc) {
+		/*
+		 * "-t <pattern>" is used to filter out fstab entries, but for ordinary
+		 * mount operation -t means "-t <type>". We have to zeroize the pattern
+		 * to avoid misinterpretation.
+		 */
+		char *pattern = cxt->fstype_pattern;
+		cxt->fstype_pattern = NULL;
+
+		rc = mnt_context_mount(cxt);
+
+		cxt->fstype_pattern = pattern;
+
+		if (mntrc)
+			*mntrc = rc;
+	}
+
+	if (mnt_context_is_child(cxt)) {
+		DBG(CXT, ul_debugobj(cxt, "next-mount: child exit [rc=%d]", rc));
+		DBG_FLUSH;
+		_exit(rc);
+	}
+	return 0;
+}
+
+
+/**
+ * mnt_context_next_remount:
+ * @cxt: context
+ * @itr: iterator
+ * @fs: returns the current filesystem
+ * @mntrc: returns the return code from mnt_context_mount()
+ * @ignored: returns 1 for non-matching
+ *
+ * This function tries to remount the next mounted filesystem (as returned by
+ * mnt_context_get_mtab()).
+ *
+ * You can filter out filesystems by:
+ *	mnt_context_set_options_pattern() to simulate mount -a -O pattern
+ *	mnt_context_set_fstype_pattern()  to simulate mount -a -t pattern
+ *
+ * If the filesystem does not match defined criteria, then the
+ * mnt_context_next_remount() function returns zero, but the @ignored is
+ * non-zero.
+ *
+ * IMPORTANT -- the mount operation is performed in the current context.
+ * The context is reset before the next mount (see mnt_reset_context()).
+ * The context setting related to the filesystem (e.g. mount options,
+ * etc.) are protected.
+
+ * If mount(2) syscall or mount.type helper failed, then the
+ * mnt_context_next_mount() function returns zero, but the @mntrc is non-zero.
+ * Use also mnt_context_get_status() to check if the filesystem was
+ * successfully mounted.
+ *
+ * See mnt_context_mount() for more details about errors and warnings.
+ *
+ * Returns: 0 on success,
+ *         <0 in case of error (!= mount(2) errors)
+ *          1 at the end of the list.
+ *
+ * Since: 2.34
+ */
+int mnt_context_next_remount(struct libmnt_context *cxt,
+			   struct libmnt_iter *itr,
+			   struct libmnt_fs **fs,
+			   int *mntrc,
+			   int *ignored)
+{
+	struct libmnt_table *mountinfo;
+	const char *tgt;
+	int rc;
+
+	if (ignored)
+		*ignored = 0;
+	if (mntrc)
+		*mntrc = 0;
+
+	if (!cxt || !fs || !itr)
+		return -EINVAL;
+
+	rc = mnt_context_get_mountinfo(cxt, &mountinfo);
+	if (rc)
+		return rc;
+
+	rc = mnt_table_next_fs(mountinfo, itr, fs);
+	if (rc != 0)
+		return rc;	/* more filesystems (or error) */
+
+	tgt = mnt_fs_get_target(*fs);
+
+	DBG(CXT, ul_debugobj(cxt, "next-remount: trying %s", tgt));
+
+	/* ignore filesystems which don't match options patterns */
+	if ((cxt->fstype_pattern && !mnt_fs_match_fstype(*fs,
+					cxt->fstype_pattern)) ||
+
+	/* ignore filesystems which don't match type patterns */
+	   (cxt->optstr_pattern && !mnt_fs_match_options(*fs,
+					cxt->optstr_pattern))) {
+		if (ignored)
+			*ignored = 1;
+		DBG(CXT, ul_debugobj(cxt, "next-remount: not-match "
+				"[fstype: %s, t-pattern: %s, options: %s, O-pattern: %s]",
+				mnt_fs_get_fstype(*fs),
+				cxt->fstype_pattern,
+				mnt_fs_get_options(*fs),
+				cxt->optstr_pattern));
+		return 0;
+	}
+
+	/* Save mount options, etc. -- this is effective for the first
+	 * mnt_context_next_remount() call only. Make sure that cxt has not set
+	 * source, target or fstype.
+	 */
+	if (!mnt_context_has_template(cxt)) {
+		mnt_context_set_source(cxt, NULL);
+		mnt_context_set_target(cxt, NULL);
+		mnt_context_set_fstype(cxt, NULL);
+		mnt_context_save_template(cxt);
+	}
+
+	/* restore original, but protect mountinfo */
+	cxt->mountinfo = NULL;
+	mnt_reset_context(cxt);
+	cxt->mountinfo = mountinfo;
+
+	rc = mnt_context_set_target(cxt, tgt);
+	if (!rc) {
+		/*
+		 * "-t <pattern>" is used to filter out fstab entries, but for ordinary
+		 * mount operation -t means "-t <type>". We have to zeroize the pattern
+		 * to avoid misinterpretation.
+		 */
+		char *pattern = cxt->fstype_pattern;
+		cxt->fstype_pattern = NULL;
+
+		rc = mnt_context_mount(cxt);
+
+		cxt->fstype_pattern = pattern;
+
+		if (mntrc)
+			*mntrc = rc;
+		rc = 0;
+	}
+
+	return rc;
+}
+
+/*
+ * Returns 1 if @dir parent is shared
+ */
+static int is_shared_tree(struct libmnt_context *cxt, const char *dir)
+{
+	struct libmnt_table *tb = NULL;
+	struct libmnt_fs *fs;
+	unsigned long mflags = 0;
+	char *mnt = NULL, *p;
+	int rc = 0;
+	struct libmnt_ns *ns_old;
+
+	ns_old = mnt_context_switch_target_ns(cxt);
+	if (!ns_old)
+		return -MNT_ERR_NAMESPACE;
+
+	if (!dir)
+		return 0;
+	if (mnt_context_get_mountinfo(cxt, &tb) || !tb)
+		goto done;
+
+	mnt = strdup(dir);
+	if (!mnt)
+		goto done;
+	p = strrchr(mnt, '/');
+	if (!p)
+		goto done;
+	if (p > mnt)
+		*p = '\0';
+	fs = mnt_table_find_mountpoint(tb, mnt, MNT_ITER_BACKWARD);
+
+	rc = fs && mnt_fs_is_kernel(fs)
+		&& mnt_fs_get_propagation(fs, &mflags) == 0
+		&& (mflags & MS_SHARED);
+done:
+	free(mnt);
+	if (!mnt_context_switch_ns(cxt, ns_old))
+		return -MNT_ERR_NAMESPACE;
+	return rc;
+}
+
+int mnt_context_get_mount_excode(
+			struct libmnt_context *cxt,
+			int rc,
+			char *buf,
+			size_t bufsz)
+{
+	int syserr;
+	struct stat st;
+	unsigned long uflags = 0, mflags = 0;
+
+	int restricted = mnt_context_is_restricted(cxt);
+	const char *tgt = mnt_context_get_target(cxt);
+	const char *src = mnt_context_get_source(cxt);
+
+	if (mnt_context_helper_executed(cxt)) {
+		/*
+		 * /sbin/mount.<type> called, return status
+		 */
+		if (rc == -MNT_ERR_APPLYFLAGS && buf)
+			snprintf(buf, bufsz, _("WARNING: failed to apply propagation flags"));
+
+		return mnt_context_get_helper_status(cxt);
+	}
+
+	if (rc == 0 && mnt_context_get_status(cxt) == 1) {
+		/*
+		 * Libmount success && syscall success.
+		 */
+		if (buf && mnt_context_forced_rdonly(cxt))
+			snprintf(buf, bufsz, _("WARNING: source write-protected, mounted read-only"));
+		return MNT_EX_SUCCESS;
+	}
+
+	mnt_context_get_mflags(cxt, &mflags);		/* mount(2) flags */
+	mnt_context_get_user_mflags(cxt, &uflags);	/* userspace flags */
+
+	if (!mnt_context_syscall_called(cxt)) {
+		/*
+		 * libmount errors (extra library checks)
+		 */
+		switch (rc) {
+		case -EPERM:
+			if (buf)
+				snprintf(buf, bufsz, _("operation permitted for root only"));
+			return MNT_EX_USAGE;
+		case -EBUSY:
+			if (buf)
+				snprintf(buf, bufsz, _("%s is already mounted"), src);
+			return MNT_EX_USAGE;
+		case -MNT_ERR_NOFSTAB:
+			if (!buf)
+				return MNT_EX_USAGE;
+			if (mnt_context_is_swapmatch(cxt))
+				snprintf(buf, bufsz, _("can't find in %s"),
+						mnt_get_fstab_path());
+			else if (tgt)
+				snprintf(buf, bufsz, _("can't find mount point in %s"),
+						mnt_get_fstab_path());
+			else if (src)
+				snprintf(buf, bufsz, _("can't find mount source %s in %s"),
+						src, mnt_get_fstab_path());
+			return MNT_EX_USAGE;
+		case -MNT_ERR_AMBIFS:
+			if (buf)
+				snprintf(buf, bufsz, _("more filesystems detected on %s; use -t <type> or wipefs(8)"), src);
+			return MNT_EX_USAGE;
+		case -MNT_ERR_NOFSTYPE:
+			if (buf)
+				snprintf(buf, bufsz, restricted ?
+						_("failed to determine filesystem type") :
+						_("no valid filesystem type specified"));
+			return MNT_EX_USAGE;
+		case -MNT_ERR_NOSOURCE:
+			if (uflags & MNT_MS_NOFAIL)
+				return MNT_EX_SUCCESS;
+			if (buf) {
+				if (src)
+					snprintf(buf, bufsz, _("can't find %s"), src);
+				else
+					snprintf(buf, bufsz, _("no mount source specified"));
+			}
+			return MNT_EX_USAGE;
+		case -MNT_ERR_MOUNTOPT:
+			if (buf) {
+				const char *opts = mnt_context_get_options(cxt);
+
+				if (!opts)
+					opts = "";
+				if (opts)
+					snprintf(buf, bufsz, errno ?
+						_("failed to parse mount options '%s': %m") :
+						_("failed to parse mount options '%s'"), opts);
+				else
+					snprintf(buf, bufsz, errno ?
+						_("failed to parse mount options: %m") :
+						_("failed to parse mount options"));
+			}
+			return MNT_EX_USAGE;
+		case -MNT_ERR_LOOPDEV:
+			if (buf)
+				snprintf(buf, bufsz, _("failed to setup loop device for %s"), src);
+			return MNT_EX_FAIL;
+		case -MNT_ERR_LOOPOVERLAP:
+			if (buf)
+				snprintf(buf, bufsz, _("overlapping loop device exists for %s"), src);
+			return MNT_EX_FAIL;
+		case -MNT_ERR_LOCK:
+			if (buf)
+				snprintf(buf, bufsz, _("locking failed"));
+			return MNT_EX_FILEIO;
+		case -MNT_ERR_NAMESPACE:
+			if (buf)
+				snprintf(buf, bufsz, _("failed to switch namespace"));
+			return MNT_EX_SYSERR;
+		case -MNT_ERR_ONLYONCE:
+			if (buf)
+				snprintf(buf, bufsz, _("filesystem already mounted"));
+			return MNT_EX_FAIL;
+		default:
+			return mnt_context_get_generic_excode(rc, buf, bufsz, _("mount failed: %m"));
+		}
+
+	} else if (mnt_context_get_syscall_errno(cxt) == 0) {
+		/*
+		 * mount(2) syscall success, but something else failed
+		 * (probably error in utab processing).
+		 */
+		if (rc == -MNT_ERR_APPLYFLAGS) {
+			if (buf)
+				snprintf(buf, bufsz, _("filesystem was mounted, but failed to apply flags"));
+			return MNT_EX_USAGE;
+		}
+
+		if (rc == -MNT_ERR_LOCK) {
+			if (buf)
+				snprintf(buf, bufsz, _("filesystem was mounted, but failed to update userspace mount table"));
+			return MNT_EX_FILEIO;
+		}
+
+		if (rc == -MNT_ERR_NAMESPACE) {
+			if (buf)
+				snprintf(buf, bufsz, _("filesystem was mounted, but failed to switch namespace back"));
+			return MNT_EX_SYSERR;
+		}
+
+		if (rc == -MNT_ERR_CHOWN) {
+			if (buf)
+				snprintf(buf, bufsz, _("filesystem was mounted, but failed to change ownership: %m"));
+			return MNT_EX_SYSERR;
+		}
+
+		if (rc == -MNT_ERR_CHMOD) {
+			if (buf)
+				snprintf(buf, bufsz, _("filesystem was mounted, but failed to change mode: %m"));
+			return MNT_EX_SYSERR;
+		}
+
+		if (rc == -MNT_ERR_IDMAP) {
+			if (buf)
+				snprintf(buf, bufsz, _("filesystem was mounted, but failed to attach idmapping"));
+			return MNT_EX_SYSERR;
+		}
+
+		if (rc < 0)
+			return mnt_context_get_generic_excode(rc, buf, bufsz,
+				_("filesystem was mounted, but any subsequent operation failed: %m"));
+
+		return MNT_EX_SOFTWARE;	/* internal error */
+
+	}
+
+	/*
+	 * mount(2) and other mount related syscalls errors
+	 */
+	syserr = mnt_context_get_syscall_errno(cxt);
+
+
+	switch(syserr) {
+	case EPERM:
+		if (!buf)
+			break;
+		if (geteuid() == 0) {
+
+			if (mnt_safe_stat(tgt, &st) == 0
+			    && ((mflags & MS_BIND && S_ISREG(st.st_mode))
+				|| S_ISDIR(st.st_mode)))
+				snprintf(buf, bufsz, _("permission denied"));
+			else
+				snprintf(buf, bufsz, _("mount point is not a directory"));
+		} else
+			snprintf(buf, bufsz, _("must be superuser to use mount"));
+		break;
+
+	case EBUSY:
+		if (!buf)
+			break;
+		if (mflags & MS_REMOUNT) {
+			snprintf(buf, bufsz, _("mount point is busy"));
+			break;
+		}
+		if (src) {
+			struct libmnt_fs *fs = get_already_mounted_source(cxt);
+
+			if (fs && mnt_fs_get_target(fs))
+				snprintf(buf, bufsz, _("%s already mounted on %s"),
+						src, mnt_fs_get_target(fs));
+		}
+		if (!*buf)
+			snprintf(buf, bufsz, _("%s already mounted or mount point busy"), src);
+		break;
+	case ENOENT:
+		if (tgt && mnt_safe_lstat(tgt, &st)) {
+			if (buf)
+				snprintf(buf, bufsz, _("mount point does not exist"));
+		} else if (tgt && mnt_safe_stat(tgt, &st)) {
+			if (buf)
+				snprintf(buf, bufsz, _("mount point is a symbolic link to nowhere"));
+		} else if (src && !mnt_is_path(src)) {
+			if (uflags & MNT_MS_NOFAIL)
+				return MNT_EX_SUCCESS;
+			if (buf)
+				snprintf(buf, bufsz, _("special device %s does not exist"), src);
+		} else if (buf) {
+			errno = syserr;
+			snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+		}
+		break;
+
+	case ENOTDIR:
+		if (mnt_safe_stat(tgt, &st) || ! S_ISDIR(st.st_mode)) {
+			if (buf)
+				snprintf(buf, bufsz, _("mount point is not a directory"));
+		} else if (src && !mnt_is_path(src)) {
+			if (uflags & MNT_MS_NOFAIL)
+				return MNT_EX_SUCCESS;
+			if (buf)
+				snprintf(buf, bufsz, _("special device %s does not exist "
+					 "(a path prefix is not a directory)"), src);
+		} else if (buf) {
+			errno = syserr;
+			snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+		}
+		break;
+
+	case EINVAL:
+		if (!buf)
+			break;
+		if (mflags & MS_REMOUNT)
+			snprintf(buf, bufsz, _("mount point not mounted or bad option"));
+		else if (rc == -MNT_ERR_APPLYFLAGS)
+			snprintf(buf, bufsz, _("not mount point or bad option"));
+		else if ((mflags & MS_MOVE) && is_shared_tree(cxt, src))
+			snprintf(buf, bufsz,
+				_("bad option; moving a mount "
+				  "residing under a shared mount is unsupported"));
+		else if (mnt_fs_is_netfs(mnt_context_get_fs(cxt)))
+			snprintf(buf, bufsz,
+				_("bad option; for several filesystems (e.g. nfs, cifs) "
+				  "you might need a /sbin/mount.<type> helper program"));
+		else
+			snprintf(buf, bufsz,
+				_("wrong fs type, bad option, bad superblock on %s, "
+				  "missing codepage or helper program, or other error"),
+				src);
+		break;
+
+	case EMFILE:
+		if (buf)
+			snprintf(buf, bufsz, _("mount table full"));
+		break;
+
+	case EIO:
+		if (buf)
+			snprintf(buf, bufsz, _("can't read superblock on %s"), src);
+		break;
+
+	case ENODEV:
+		if (!buf)
+			break;
+		if (mnt_context_get_fstype(cxt))
+			snprintf(buf, bufsz, _("unknown filesystem type '%s'"),
+					mnt_context_get_fstype(cxt));
+		else
+			snprintf(buf, bufsz, _("unknown filesystem type"));
+		break;
+
+	case ENOTBLK:
+		if (uflags & MNT_MS_NOFAIL)
+			return MNT_EX_SUCCESS;
+		if (!buf)
+			break;
+		if (src && mnt_safe_stat(src, &st))
+			snprintf(buf, bufsz, _("%s is not a block device, and stat(2) fails?"), src);
+		else if (src && S_ISBLK(st.st_mode))
+			snprintf(buf, bufsz,
+				_("the kernel does not recognize %s as a block device; "
+				  "maybe \"modprobe driver\" is necessary"), src);
+		else if (src && S_ISREG(st.st_mode))
+			snprintf(buf, bufsz, _("%s is not a block device; try \"-o loop\""), src);
+		else
+			snprintf(buf, bufsz, _("%s is not a block device"), src);
+		break;
+
+	case ENXIO:
+		if (uflags & MNT_MS_NOFAIL)
+			return MNT_EX_SUCCESS;
+		if (buf)
+			snprintf(buf, bufsz, _("%s is not a valid block device"), src);
+		break;
+
+	case EACCES:
+	case EROFS:
+		if (!buf)
+			break;
+		if (mflags & MS_RDONLY)
+			snprintf(buf, bufsz, _("cannot mount %s read-only"), src);
+		else if (mnt_context_is_rwonly_mount(cxt))
+			snprintf(buf, bufsz, _("%s is write-protected but explicit read-write mode requested"), src);
+		else if (mflags & MS_REMOUNT)
+			snprintf(buf, bufsz, _("cannot remount %s read-write, is write-protected"), src);
+		else if (mflags & MS_BIND)
+			snprintf(buf, bufsz, _("bind %s failed"), src);
+		else {
+			errno = syserr;
+			snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+		}
+		break;
+
+	case ENOMEDIUM:
+		if (uflags & MNT_MS_NOFAIL)
+			return MNT_EX_SUCCESS;
+		if (buf)
+			snprintf(buf, bufsz, _("no medium found on %s"), src);
+		break;
+
+	case EBADMSG:
+		/* Bad CRC for classic filesystems (e.g. extN or XFS) */
+		if (buf && src && mnt_safe_stat(src, &st) == 0
+		    && (S_ISBLK(st.st_mode) || S_ISREG(st.st_mode))) {
+			snprintf(buf, bufsz, _("cannot mount; probably corrupted filesystem on %s"), src);
+			break;
+		}
+		/* fallthrough */
+
+	default:
+		if (buf) {
+			errno = syserr;
+			snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+		}
+		break;
+	}
+
+	return MNT_EX_FAIL;
+}
+
+#ifdef TEST_PROGRAM
+
+static int test_perms(struct libmnt_test *ts, int argc, char *argv[])
+{
+	struct libmnt_context *cxt;
+	struct libmnt_optlist *ls;
+	int rc;
+
+	cxt = mnt_new_context();
+	if (!cxt)
+		return -ENOMEM;
+
+	cxt->restricted = 1;		/* emulate suid mount(8) */
+	mnt_context_get_fs(cxt);	/* due to assert() in evaluate_permissions() */
+
+	if (argc < 2) {
+		 warn("missing fstab options");
+		 return -EPERM;
+	}
+	if (argc == 3 && strcmp(argv[2], "--root") == 0)
+		cxt->restricted = 0;
+
+	ls = mnt_context_get_optlist(cxt);
+	if (!ls)
+		return -ENOMEM;
+	rc = mnt_optlist_set_optstr(ls, argv[1], NULL);
+	if (rc) {
+		warn("cannot apply fstab options");
+		return rc;
+	}
+	cxt->flags |= MNT_FL_TAB_APPLIED;	/* emulate mnt_context_apply_fstab() */
+
+	mnt_context_merge_mflags(cxt);
+
+	rc = evaluate_permissions(cxt);
+	if (rc) {
+		warn("evaluate permission failed [rc=%d]", rc);
+		return rc;
+	}
+	printf("user can mount\n");
+
+	mnt_free_context(cxt);
+	return 0;
+}
+
+static int test_fixopts(struct libmnt_test *ts, int argc, char *argv[])
+{
+	struct libmnt_context *cxt;
+	struct libmnt_optlist *ls;
+	unsigned long flags = 0;
+	const char *p;
+	int rc;
+
+	cxt = mnt_new_context();
+	if (!cxt)
+		return -ENOMEM;
+
+	cxt->restricted = 1;		/* emulate suid mount(8) */
+	mnt_context_get_fs(cxt);	/* to fill fs->*_optstr */
+
+	if (argc < 2) {
+		 warn("missing fstab options");
+		 return -EPERM;
+	}
+	if (argc == 3 && strcmp(argv[2], "--root") == 0)
+		cxt->restricted = 0;
+
+	ls = mnt_context_get_optlist(cxt);
+	if (!ls)
+		return -ENOMEM;
+	rc = mnt_optlist_set_optstr(ls, argv[1], NULL);
+	if (rc) {
+		warn("cannot apply fstab options");
+		return rc;
+	}
+	cxt->flags |= MNT_FL_TAB_APPLIED;	/* emulate mnt_context_apply_fstab() */
+
+	mnt_context_merge_mflags(cxt);
+
+	rc = evaluate_permissions(cxt);
+	if (rc) {
+		warn("evaluate permission failed [rc=%d]", rc);
+		return rc;
+	}
+	rc = fix_optstr(cxt);
+	if (rc) {
+		warn("fix options failed [rc=%d]", rc);
+		return rc;
+	}
+
+	mnt_optlist_get_optstr(ls, &p, NULL, 0);
+
+	mnt_optlist_get_flags(ls, &flags, cxt->map_linux, 0);
+	printf("options (dfl): '%s' [mount flags: %08lx]\n", p, flags);
+
+	mnt_optlist_get_optstr(ls, &p, NULL, MNT_OL_FLTR_ALL);
+	printf("options (ex.): '%s'\n", p);
+
+	mnt_free_context(cxt);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	struct libmnt_test tss[] = {
+	{ "--perms",		test_perms,    "<fstab-options> [--root]" },
+	{ "--fix-options",	test_fixopts,  "<fstab-options> [--root]" },
+
+	{ NULL }};
+
+	return mnt_run_test(tss, argc, argv);
+}
+
+#endif /* TEST_PROGRAM */