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-rw-r--r--libmount/src/tab.c2206
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diff --git a/libmount/src/tab.c b/libmount/src/tab.c
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+
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * This file is part of libmount from util-linux project.
+ *
+ * Copyright (C) 2008-2018 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: table
+ * @title: Table of filesystems
+ * @short_description: container for entries from fstab, mtab or mountinfo
+ *
+ * Note that mnt_table_find_* functions are mount(8) compatible. These functions
+ * try to find an entry in more iterations, where the first attempt is always
+ * based on comparison with unmodified (non-canonicalized or un-evaluated)
+ * paths or tags. For example a fstab with two entries:
+ * <informalexample>
+ * <programlisting>
+ * LABEL=foo /foo auto rw
+ * /dev/foo /foo auto rw
+ * </programlisting>
+ * </informalexample>
+ *
+ * where both lines are used for the *same* device, then
+ * <informalexample>
+ * <programlisting>
+ * mnt_table_find_source(tb, "/dev/foo", &fs);
+ * </programlisting>
+ * </informalexample>
+ * will returns the second line, and
+ * <informalexample>
+ * <programlisting>
+ * mnt_table_find_source(tb, "LABEL=foo", &fs);
+ * </programlisting>
+ * </informalexample>
+ * will returns the first entry, and
+ * <informalexample>
+ * <programlisting>
+ * mnt_table_find_source(tb, "UUID=anyuuid", &fs);
+ * </programlisting>
+ * </informalexample>
+ * will return the first entry (if UUID matches with the device).
+ */
+#include <blkid.h>
+
+#include "mountP.h"
+#include "strutils.h"
+#include "loopdev.h"
+#include "fileutils.h"
+#include "canonicalize.h"
+
+int is_mountinfo(struct libmnt_table *tb)
+{
+ struct libmnt_fs *fs;
+
+ if (!tb)
+ return 0;
+
+ fs = list_first_entry(&tb->ents, struct libmnt_fs, ents);
+ if (fs && mnt_fs_is_kernel(fs) && mnt_fs_get_root(fs))
+ return 1;
+
+ return 0;
+}
+
+/**
+ * mnt_new_table:
+ *
+ * The tab is a container for struct libmnt_fs entries that usually represents a fstab,
+ * mtab or mountinfo file from your system.
+ *
+ * See also mnt_table_parse_file().
+ *
+ * Returns: newly allocated tab struct.
+ */
+struct libmnt_table *mnt_new_table(void)
+{
+ struct libmnt_table *tb = NULL;
+
+ tb = calloc(1, sizeof(*tb));
+ if (!tb)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "alloc"));
+ tb->refcount = 1;
+ INIT_LIST_HEAD(&tb->ents);
+ return tb;
+}
+
+/**
+ * mnt_reset_table:
+ * @tb: tab pointer
+ *
+ * Removes all entries (filesystems) from the table. The filesystems with zero
+ * reference count will be deallocated.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_reset_table(struct libmnt_table *tb)
+{
+ if (!tb)
+ return -EINVAL;
+
+ DBG(TAB, ul_debugobj(tb, "reset"));
+
+ while (!list_empty(&tb->ents)) {
+ struct libmnt_fs *fs = list_entry(tb->ents.next,
+ struct libmnt_fs, ents);
+ mnt_table_remove_fs(tb, fs);
+ }
+
+ tb->nents = 0;
+ return 0;
+}
+
+/**
+ * mnt_ref_table:
+ * @tb: table pointer
+ *
+ * Increments reference counter.
+ */
+void mnt_ref_table(struct libmnt_table *tb)
+{
+ if (tb) {
+ tb->refcount++;
+ /*DBG(FS, ul_debugobj(tb, "ref=%d", tb->refcount));*/
+ }
+}
+
+/**
+ * mnt_unref_table:
+ * @tb: table pointer
+ *
+ * De-increments reference counter, on zero the @tb is automatically
+ * deallocated by mnt_free_table().
+ */
+void mnt_unref_table(struct libmnt_table *tb)
+{
+ if (tb) {
+ tb->refcount--;
+ /*DBG(FS, ul_debugobj(tb, "unref=%d", tb->refcount));*/
+ if (tb->refcount <= 0)
+ mnt_free_table(tb);
+ }
+}
+
+
+/**
+ * mnt_free_table:
+ * @tb: tab pointer
+ *
+ * Deallocates the table. This function does not care about reference count. Don't
+ * use this function directly -- it's better to use mnt_unref_table().
+ *
+ * The table entries (filesystems) are unreferenced by mnt_reset_table() and
+ * cache by mnt_unref_cache().
+ */
+void mnt_free_table(struct libmnt_table *tb)
+{
+ if (!tb)
+ return;
+
+ mnt_reset_table(tb);
+ DBG(TAB, ul_debugobj(tb, "free [refcount=%d]", tb->refcount));
+
+ mnt_unref_cache(tb->cache);
+ free(tb->comm_intro);
+ free(tb->comm_tail);
+ free(tb);
+}
+
+/**
+ * mnt_table_get_nents:
+ * @tb: pointer to tab
+ *
+ * Returns: number of entries in table.
+ */
+int mnt_table_get_nents(struct libmnt_table *tb)
+{
+ return tb ? tb->nents : 0;
+}
+
+/**
+ * mnt_table_is_empty:
+ * @tb: pointer to tab
+ *
+ * Returns: 1 if the table is without filesystems, or 0.
+ */
+int mnt_table_is_empty(struct libmnt_table *tb)
+{
+ return tb == NULL || list_empty(&tb->ents) ? 1 : 0;
+}
+
+/**
+ * mnt_table_set_userdata:
+ * @tb: pointer to tab
+ * @data: pointer to user data
+ *
+ * Sets pointer to the private user data.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_set_userdata(struct libmnt_table *tb, void *data)
+{
+ if (!tb)
+ return -EINVAL;
+
+ tb->userdata = data;
+ return 0;
+}
+
+/**
+ * mnt_table_get_userdata:
+ * @tb: pointer to tab
+ *
+ * Returns: pointer to user's data.
+ */
+void *mnt_table_get_userdata(struct libmnt_table *tb)
+{
+ return tb ? tb->userdata : NULL;
+}
+
+/**
+ * mnt_table_enable_comments:
+ * @tb: pointer to tab
+ * @enable: TRUE or FALSE
+ *
+ * Enables parsing of comments.
+ *
+ * The initial (intro) file comment is accessible by
+ * mnt_table_get_intro_comment(). The intro and the comment of the first fstab
+ * entry has to be separated by blank line. The filesystem comments are
+ * accessible by mnt_fs_get_comment(). The trailing fstab comment is accessible
+ * by mnt_table_get_trailing_comment().
+ *
+ * <informalexample>
+ * <programlisting>
+ * #
+ * # Intro comment
+ * #
+ *
+ * # this comments belongs to the first fs
+ * LABEL=foo /mnt/foo auto defaults 1 2
+ * # this comments belongs to the second fs
+ * LABEL=bar /mnt/bar auto defaults 1 2
+ * # tailing comment
+ * </programlisting>
+ * </informalexample>
+ */
+void mnt_table_enable_comments(struct libmnt_table *tb, int enable)
+{
+ if (tb)
+ tb->comms = enable;
+}
+
+/**
+ * mnt_table_with_comments:
+ * @tb: pointer to table
+ *
+ * Returns: 1 if comments parsing is enabled, or 0.
+ */
+int mnt_table_with_comments(struct libmnt_table *tb)
+{
+ assert(tb);
+ return tb ? tb->comms : 0;
+}
+
+/**
+ * mnt_table_get_intro_comment:
+ * @tb: pointer to tab
+ *
+ * Returns: initial comment in tb
+ */
+const char *mnt_table_get_intro_comment(struct libmnt_table *tb)
+{
+ return tb ? tb->comm_intro : NULL;
+}
+
+/**
+ * mnt_table_set_into_comment:
+ * @tb: pointer to tab
+ * @comm: comment or NULL
+ *
+ * Sets the initial comment in tb.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_set_intro_comment(struct libmnt_table *tb, const char *comm)
+{
+ return strdup_to_struct_member(tb, comm_intro, comm);
+}
+
+/**
+ * mnt_table_append_into_comment:
+ * @tb: pointer to tab
+ * @comm: comment of NULL
+ *
+ * Appends the initial comment in tb.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_append_intro_comment(struct libmnt_table *tb, const char *comm)
+{
+ if (!tb)
+ return -EINVAL;
+ return append_string(&tb->comm_intro, comm);
+}
+
+/**
+ * mnt_table_get_trailing_comment:
+ * @tb: pointer to tab
+ *
+ * Returns: table trailing comment
+ */
+const char *mnt_table_get_trailing_comment(struct libmnt_table *tb)
+{
+ return tb ? tb->comm_tail : NULL;
+}
+
+/**
+ * mnt_table_set_trailing_comment
+ * @tb: pointer to tab
+ * @comm: comment string
+ *
+ * Sets the trailing comment in table.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_set_trailing_comment(struct libmnt_table *tb, const char *comm)
+{
+ return strdup_to_struct_member(tb, comm_tail, comm);
+}
+
+/**
+ * mnt_table_append_trailing_comment:
+ * @tb: pointer to tab
+ * @comm: comment of NULL
+ *
+ * Appends to the trailing table comment.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_append_trailing_comment(struct libmnt_table *tb, const char *comm)
+{
+ if (!tb)
+ return -EINVAL;
+ return append_string(&tb->comm_tail, comm);
+}
+
+/**
+ * mnt_table_set_cache:
+ * @tb: pointer to tab
+ * @mpc: pointer to struct libmnt_cache instance
+ *
+ * Sets up a cache for canonicalized paths and evaluated tags (LABEL/UUID). The
+ * cache is recommended for mnt_table_find_*() functions.
+ *
+ * The cache could be shared between more tabs. Be careful when you share the
+ * same cache between more threads -- currently the cache does not provide any
+ * locking method.
+ *
+ * This function increments cache reference counter. It's recommended to use
+ * mnt_unref_cache() after mnt_table_set_cache() if you want to keep the cache
+ * referenced by @tb only.
+ *
+ * See also mnt_new_cache().
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_set_cache(struct libmnt_table *tb, struct libmnt_cache *mpc)
+{
+ if (!tb)
+ return -EINVAL;
+
+ mnt_ref_cache(mpc); /* new */
+ mnt_unref_cache(tb->cache); /* old */
+ tb->cache = mpc;
+ return 0;
+}
+
+/**
+ * mnt_table_get_cache:
+ * @tb: pointer to tab
+ *
+ * Returns: pointer to struct libmnt_cache instance or NULL.
+ */
+struct libmnt_cache *mnt_table_get_cache(struct libmnt_table *tb)
+{
+ return tb ? tb->cache : NULL;
+}
+
+/**
+ * mnt_table_find_fs:
+ * @tb: tab pointer
+ * @fs: entry to look for
+ *
+ * Checks if @fs is part of table @tb.
+ *
+ * Returns: index of @fs in table, 0 if not found or negative number in case of error.
+ *
+ * Since: 2.34
+ */
+int mnt_table_find_fs(struct libmnt_table *tb, struct libmnt_fs *fs)
+{
+ struct list_head *p;
+ int i = 0;
+
+ if (!tb || !fs)
+ return -EINVAL;
+
+ if (list_empty(&fs->ents))
+ return 0;
+
+ /* Let's use directly list rather than mnt_table_next_fs() as we
+ * compare list entry with fs only.
+ */
+ list_for_each(p, &tb->ents) {
+ ++i;
+ if (list_entry(p, struct libmnt_fs, ents) == fs)
+ return i;
+ }
+
+ return 0;
+}
+
+/**
+ * mnt_table_add_fs:
+ * @tb: tab pointer
+ * @fs: new entry
+ *
+ * Adds a new entry to tab and increment @fs reference counter. Don't forget to
+ * use mnt_unref_fs() after mnt_table_add_fs() you want to keep the @fs
+ * referenced by the table only.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_add_fs(struct libmnt_table *tb, struct libmnt_fs *fs)
+{
+ if (!tb || !fs)
+ return -EINVAL;
+
+ if (fs->tab)
+ return -EBUSY;
+
+ mnt_ref_fs(fs);
+ list_add_tail(&fs->ents, &tb->ents);
+ fs->tab = tb;
+ tb->nents++;
+
+ DBG(TAB, ul_debugobj(tb, "add entry: %s %s",
+ mnt_fs_get_source(fs), mnt_fs_get_target(fs)));
+ return 0;
+}
+
+static int __table_insert_fs(
+ struct libmnt_table *tb, int before,
+ struct libmnt_fs *pos, struct libmnt_fs *fs)
+{
+ struct list_head *head = pos ? &pos->ents : &tb->ents;
+
+ if (before)
+ list_add(&fs->ents, head);
+ else
+ list_add_tail(&fs->ents, head);
+
+ fs->tab = tb;
+ tb->nents++;
+
+ DBG(TAB, ul_debugobj(tb, "insert entry: %s %s",
+ mnt_fs_get_source(fs), mnt_fs_get_target(fs)));
+ return 0;
+}
+
+/**
+ * mnt_table_insert_fs:
+ * @tb: tab pointer
+ * @before: 1 to insert before pos, 0 to insert after pos
+ * @pos: entry to specify position or NULL
+ * @fs: new entry
+ *
+ * Adds a new entry to @tb before or after a specific table entry @pos. If the
+ * @pos is NULL than add the begin of the @tab if @before is 1; or to the tail
+ * of the @tb if @before is 0.
+ *
+ * This function increments reference to @fs. Don't forget to use
+ * mnt_unref_fs() after mnt_table_insert_fs() if you want to keep the @fs
+ * referenced by the table only.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ *
+ * Since: 2.34
+ */
+int mnt_table_insert_fs(struct libmnt_table *tb, int before,
+ struct libmnt_fs *pos, struct libmnt_fs *fs)
+{
+ if (!tb || !fs)
+ return -EINVAL;
+
+ if (fs->tab)
+ return -EBUSY;
+
+ if (pos && pos->tab != tb)
+ return -ENOENT;
+
+ mnt_ref_fs(fs);
+ return __table_insert_fs(tb, before, pos, fs);
+}
+
+/**
+ * mnt_table_move_fs:
+ * @src: tab pointer of source table
+ * @dst: tab pointer of destination table
+ * @before: 1 to move before position, 0 to move after position
+ * @pos: entry to specify position or NULL
+ * @fs: entry to move
+ *
+ * Removes @fs from @src table and adds it before/after a specific entry @pos
+ * of @dst table. If the @pos is NULL than add the begin of the @dst if @before
+ * is 1; or to the tail of the @dst if @before is 0.
+ *
+ * The reference counter of @fs is not modified.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ *
+ * Since: 2.34
+ */
+int mnt_table_move_fs(struct libmnt_table *src, struct libmnt_table *dst,
+ int before, struct libmnt_fs *pos, struct libmnt_fs *fs)
+{
+ if (!src || !dst || !fs)
+ return -EINVAL;
+
+ if (fs->tab != src || (pos && pos->tab != dst))
+ return -ENOENT;
+
+ /* remove from source */
+ list_del_init(&fs->ents);
+ src->nents--;
+
+ /* insert to the destination */
+ return __table_insert_fs(dst, before, pos, fs);
+}
+
+
+/**
+ * mnt_table_remove_fs:
+ * @tb: tab pointer
+ * @fs: new entry
+ *
+ * Removes the @fs from the table and de-increment reference counter of the @fs. The
+ * filesystem with zero reference counter will be deallocated. Don't forget to use
+ * mnt_ref_fs() before call mnt_table_remove_fs() if you want to use @fs later.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_remove_fs(struct libmnt_table *tb, struct libmnt_fs *fs)
+{
+ if (!tb || !fs || fs->tab != tb)
+ return -EINVAL;
+
+ fs->tab = NULL;
+ list_del_init(&fs->ents);
+
+ mnt_unref_fs(fs);
+ tb->nents--;
+ return 0;
+}
+
+static inline struct libmnt_fs *get_parent_fs(struct libmnt_table *tb, struct libmnt_fs *fs)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *x;
+ int parent_id = mnt_fs_get_parent_id(fs);
+
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+ while (mnt_table_next_fs(tb, &itr, &x) == 0) {
+ if (mnt_fs_get_id(x) == parent_id)
+ return x;
+ }
+
+ return NULL;
+}
+
+/**
+ * mnt_table_get_root_fs:
+ * @tb: mountinfo file (/proc/self/mountinfo)
+ * @root: returns pointer to the root filesystem (/)
+ *
+ * The function uses the parent ID from the mountinfo file to determine the
+ * root filesystem (the filesystem with the smallest ID with parent ID missing
+ * in the table). The function is designed mostly for applications where it is
+ * necessary to sort mountpoints by IDs to get the tree of the mountpoints
+ * (e.g. findmnt default output).
+ *
+ * If you're not sure, then use
+ *
+ * mnt_table_find_target(tb, "/", MNT_ITER_BACKWARD);
+ *
+ * this is more robust and usable for arbitrary tab files (including fstab).
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_get_root_fs(struct libmnt_table *tb, struct libmnt_fs **root)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs;
+ int root_id = 0;
+
+ if (!tb || !root || !is_mountinfo(tb))
+ return -EINVAL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup root fs"));
+
+ *root = NULL;
+
+ /* get smallest possible ID from the table */
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ int id = mnt_fs_get_parent_id(fs);
+
+ if (!*root || id < root_id) {
+ *root = fs;
+ root_id = id;
+ }
+ }
+
+ /* go to the root node by "parent_id -> id" relation */
+ while (*root) {
+ struct libmnt_fs *x = get_parent_fs(tb, *root);
+ if (!x || x == *root)
+ break;
+ DBG(TAB, ul_debugobj(tb, " messy mountinfo, walk to %s", mnt_fs_get_target(x)));
+ *root = x;
+ }
+
+ return *root ? 0 : -EINVAL;
+}
+
+/**
+ * mnt_table_next_child_fs:
+ * @tb: mountinfo file (/proc/self/mountinfo)
+ * @itr: iterator
+ * @parent: parental FS
+ * @chld: returns the next child filesystem
+ *
+ * Note that filesystems are returned in the order of mounting (according to
+ * IDs in /proc/self/mountinfo).
+ *
+ * Returns: 0 on success, negative number in case of error or 1 at the end of list.
+ */
+int mnt_table_next_child_fs(struct libmnt_table *tb, struct libmnt_iter *itr,
+ struct libmnt_fs *parent, struct libmnt_fs **chld)
+{
+ struct libmnt_fs *fs;
+ int parent_id, lastchld_id = 0, chld_id = 0;
+
+ if (!tb || !itr || !parent || !is_mountinfo(tb))
+ return -EINVAL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup next child of '%s'",
+ mnt_fs_get_target(parent)));
+
+ parent_id = mnt_fs_get_id(parent);
+
+ /* get ID of the previously returned child */
+ if (itr->head && itr->p != itr->head) {
+ MNT_ITER_ITERATE(itr, fs, struct libmnt_fs, ents);
+ lastchld_id = mnt_fs_get_id(fs);
+ }
+
+ *chld = NULL;
+
+ mnt_reset_iter(itr, MNT_ITER_FORWARD);
+ while(mnt_table_next_fs(tb, itr, &fs) == 0) {
+ int id;
+
+ if (mnt_fs_get_parent_id(fs) != parent_id)
+ continue;
+
+ id = mnt_fs_get_id(fs);
+
+ /* avoid an infinite loop. This only happens in rare cases
+ * such as in early userspace when the rootfs is its own parent */
+ if (id == parent_id)
+ continue;
+
+ if ((!lastchld_id || id > lastchld_id) &&
+ (!*chld || id < chld_id)) {
+ *chld = fs;
+ chld_id = id;
+ }
+ }
+
+ if (!*chld)
+ return 1; /* end of iterator */
+
+ /* set the iterator to the @chld for the next call */
+ mnt_table_set_iter(tb, itr, *chld);
+
+ return 0;
+}
+
+/**
+ * mnt_table_next_fs:
+ * @tb: tab pointer
+ * @itr: iterator
+ * @fs: returns the next tab entry
+ *
+ * Returns: 0 on success, negative number in case of error or 1 at the end of list.
+ *
+ * Example:
+ * <informalexample>
+ * <programlisting>
+ * while(mnt_table_next_fs(tb, itr, &fs) == 0) {
+ * const char *dir = mnt_fs_get_target(fs);
+ * printf("mount point: %s\n", dir);
+ * }
+ * </programlisting>
+ * </informalexample>
+ *
+ * lists all mountpoints from fstab in reverse order.
+ */
+int mnt_table_next_fs(struct libmnt_table *tb, struct libmnt_iter *itr, struct libmnt_fs **fs)
+{
+ int rc = 1;
+
+ if (!tb || !itr || !fs)
+ return -EINVAL;
+ *fs = NULL;
+
+ if (!itr->head)
+ MNT_ITER_INIT(itr, &tb->ents);
+ if (itr->p != itr->head) {
+ MNT_ITER_ITERATE(itr, *fs, struct libmnt_fs, ents);
+ rc = 0;
+ }
+
+ return rc;
+}
+
+/**
+ * mnt_table_first_fs:
+ * @tb: tab pointer
+ * @fs: returns the first tab entry
+ *
+ * Returns: 0 on success, negative number in case of error or 1 at the end of list.
+ */
+int mnt_table_first_fs(struct libmnt_table *tb, struct libmnt_fs **fs)
+{
+ if (!tb || !fs)
+ return -EINVAL;
+ if (list_empty(&tb->ents))
+ return 1;
+ *fs = list_first_entry(&tb->ents, struct libmnt_fs, ents);
+ return 0;
+}
+
+/**
+ * mnt_table_last_fs:
+ * @tb: tab pointer
+ * @fs: returns the last tab entry
+ *
+ * Returns: 0 on success, negative number in case of error or 1 at the end of list.
+ */
+int mnt_table_last_fs(struct libmnt_table *tb, struct libmnt_fs **fs)
+{
+ if (!tb || !fs)
+ return -EINVAL;
+ if (list_empty(&tb->ents))
+ return 1;
+ *fs = list_last_entry(&tb->ents, struct libmnt_fs, ents);
+ return 0;
+}
+
+/**
+ * mnt_table_find_next_fs:
+ * @tb: table
+ * @itr: iterator
+ * @match_func: function returning 1 or 0
+ * @userdata: extra data for match_func
+ * @fs: returns pointer to the next matching table entry
+ *
+ * This function allows searching in @tb.
+ *
+ * Returns: negative number in case of error, 1 at end of table or 0 o success.
+ */
+int mnt_table_find_next_fs(struct libmnt_table *tb, struct libmnt_iter *itr,
+ int (*match_func)(struct libmnt_fs *, void *), void *userdata,
+ struct libmnt_fs **fs)
+{
+ if (!tb || !itr || !fs || !match_func)
+ return -EINVAL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup next fs"));
+
+ if (!itr->head)
+ MNT_ITER_INIT(itr, &tb->ents);
+
+ do {
+ if (itr->p != itr->head)
+ MNT_ITER_ITERATE(itr, *fs, struct libmnt_fs, ents);
+ else
+ break; /* end */
+
+ if (match_func(*fs, userdata))
+ return 0;
+ } while(1);
+
+ *fs = NULL;
+ return 1;
+}
+
+static int mnt_table_move_parent(struct libmnt_table *tb, int oldid, int newid)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs;
+
+ if (!tb)
+ return -EINVAL;
+ if (list_empty(&tb->ents))
+ return 0;
+
+ DBG(TAB, ul_debugobj(tb, "moving parent ID from %d -> %d", oldid, newid));
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+
+ while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (fs->parent == oldid)
+ fs->parent = newid;
+ }
+ return 0;
+}
+
+/**
+ * mnt_table_uniq_fs:
+ * @tb: table
+ * @flags: MNT_UNIQ_*
+ * @cmp: function to compare filesystems
+ *
+ * This function de-duplicate the @tb, but does not change order of the
+ * filesystems. The @cmp function has to return 0 if the filesystems are
+ * equal, otherwise non-zero.
+ *
+ * The default is to keep in the table later mounted filesystems (function uses
+ * backward mode iterator).
+ *
+ * @MNT_UNIQ_FORWARD: remove later mounted filesystems
+ * @MNT_UNIQ_KEEPTREE: keep parent->id relationship still valid
+ *
+ * Returns: negative number in case of error, or 0 o success.
+ */
+int mnt_table_uniq_fs(struct libmnt_table *tb, int flags,
+ int (*cmp)(struct libmnt_table *,
+ struct libmnt_fs *,
+ struct libmnt_fs *))
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs;
+ int direction = MNT_ITER_BACKWARD;
+
+ if (!tb || !cmp)
+ return -EINVAL;
+ if (list_empty(&tb->ents))
+ return 0;
+
+ if (flags & MNT_UNIQ_FORWARD)
+ direction = MNT_ITER_FORWARD;
+
+ DBG(TAB, ul_debugobj(tb, "de-duplicate"));
+ mnt_reset_iter(&itr, direction);
+
+ if ((flags & MNT_UNIQ_KEEPTREE) && !is_mountinfo(tb))
+ flags &= ~MNT_UNIQ_KEEPTREE;
+
+ while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ int want = 1;
+ struct libmnt_iter xtr;
+ struct libmnt_fs *x;
+
+ mnt_reset_iter(&xtr, direction);
+ while (want && mnt_table_next_fs(tb, &xtr, &x) == 0) {
+ if (fs == x)
+ break;
+ want = cmp(tb, x, fs) != 0;
+ }
+
+ if (!want) {
+ if (flags & MNT_UNIQ_KEEPTREE)
+ mnt_table_move_parent(tb, mnt_fs_get_id(fs),
+ mnt_fs_get_parent_id(fs));
+
+ DBG(TAB, ul_debugobj(tb, "remove duplicate %s",
+ mnt_fs_get_target(fs)));
+ mnt_table_remove_fs(tb, fs);
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * mnt_table_set_iter:
+ * @tb: tab pointer
+ * @itr: iterator
+ * @fs: tab entry
+ *
+ * Sets @iter to the position of @fs in the file @tb.
+ *
+ * Returns: 0 on success, negative number in case of error.
+ */
+int mnt_table_set_iter(struct libmnt_table *tb, struct libmnt_iter *itr, struct libmnt_fs *fs)
+{
+ if (!tb || !itr || !fs)
+ return -EINVAL;
+
+ if (fs->tab != tb)
+ return -ENOENT;
+
+ MNT_ITER_INIT(itr, &tb->ents);
+ itr->p = &fs->ents;
+
+ return 0;
+}
+
+/**
+ * mnt_table_find_mountpoint:
+ * @tb: tab pointer
+ * @path: directory
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * Same as mnt_get_mountpoint(), except this function does not rely on
+ * st_dev numbers.
+ *
+ * Returns: a tab entry or NULL.
+ */
+struct libmnt_fs *mnt_table_find_mountpoint(struct libmnt_table *tb,
+ const char *path,
+ int direction)
+{
+ char *mnt;
+ struct stat st;
+
+ if (!tb || !path || !*path)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup MOUNTPOINT: '%s'", path));
+
+ if (mnt_stat_mountpoint(path, &st))
+ return NULL;
+
+ mnt = strdup(path);
+ if (!mnt)
+ return NULL;
+
+ do {
+ char *p;
+ struct libmnt_fs *fs;
+
+ fs = mnt_table_find_target(tb, mnt, direction);
+ if (fs) {
+ free(mnt);
+ return fs;
+ }
+
+ p = stripoff_last_component(mnt);
+ if (!p)
+ break;
+ } while (mnt && *(mnt + 1) != '\0');
+
+ free(mnt);
+ return mnt_table_find_target(tb, "/", direction);
+}
+
+/**
+ * mnt_table_find_target:
+ * @tb: tab pointer
+ * @path: mountpoint directory
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * Try to lookup an entry in the given tab, three iterations are possible, the first
+ * with @path, the second with realpath(@path) and the third with realpath(@path)
+ * against realpath(fs->target). The 2nd and 3rd iterations are not performed when
+ * the @tb cache is not set (see mnt_table_set_cache()). If
+ * mnt_cache_set_targets(cache, mtab) was called, the 3rd iteration skips any
+ * @fs->target found in @mtab (see mnt_resolve_target()).
+ *
+ * Returns: a tab entry or NULL.
+ */
+struct libmnt_fs *mnt_table_find_target(struct libmnt_table *tb, const char *path, int direction)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs = NULL;
+ char *cn;
+
+ if (!tb || !path || !*path)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup TARGET: '%s'", path));
+
+ /* native @target */
+ mnt_reset_iter(&itr, direction);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (mnt_fs_streq_target(fs, path))
+ return fs;
+ }
+
+ /* try absolute path */
+ if (is_relative_path(path) && (cn = absolute_path(path))) {
+ DBG(TAB, ul_debugobj(tb, "lookup absolute TARGET: '%s'", cn));
+ mnt_reset_iter(&itr, direction);
+ while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (mnt_fs_streq_target(fs, cn)) {
+ free(cn);
+ return fs;
+ }
+ }
+ free(cn);
+ }
+
+ if (!tb->cache || !(cn = mnt_resolve_path(path, tb->cache)))
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup canonical TARGET: '%s'", cn));
+
+ /* canonicalized paths in struct libmnt_table */
+ mnt_reset_iter(&itr, direction);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (mnt_fs_streq_target(fs, cn))
+ return fs;
+ }
+
+ /* non-canonical path in struct libmnt_table
+ * -- note that mountpoint in /proc/self/mountinfo is already
+ * canonicalized by the kernel
+ */
+ mnt_reset_iter(&itr, direction);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ char *p;
+
+ if (!fs->target
+ || mnt_fs_is_swaparea(fs)
+ || mnt_fs_is_kernel(fs)
+ || (*fs->target == '/' && *(fs->target + 1) == '\0'))
+ continue;
+
+ p = mnt_resolve_target(fs->target, tb->cache);
+ /* both canonicalized, strcmp() is fine here */
+ if (p && strcmp(cn, p) == 0)
+ return fs;
+ }
+ return NULL;
+}
+
+/**
+ * mnt_table_find_srcpath:
+ * @tb: tab pointer
+ * @path: source path (devname or dirname) or NULL
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * Try to lookup an entry in the given tab, four iterations are possible, the first
+ * with @path, the second with realpath(@path), the third with tags (LABEL, UUID, ..)
+ * from @path and the fourth with realpath(@path) against realpath(entry->srcpath).
+ *
+ * The 2nd, 3rd and 4th iterations are not performed when the @tb cache is not
+ * set (see mnt_table_set_cache()).
+ *
+ * For btrfs returns tab entry for default id.
+ *
+ * Note that NULL is a valid source path; it will be replaced with "none". The
+ * "none" is used in /proc/{mounts,self/mountinfo} for pseudo filesystems.
+ *
+ * Returns: a tab entry or NULL.
+ */
+struct libmnt_fs *mnt_table_find_srcpath(struct libmnt_table *tb, const char *path, int direction)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs = NULL;
+ int ntags = 0, nents;
+ char *cn;
+ const char *p;
+
+ if (!tb || !path || !*path)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup SRCPATH: '%s'", path));
+
+ /* native paths */
+ mnt_reset_iter(&itr, direction);
+
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+
+ if (mnt_fs_streq_srcpath(fs, path)) {
+#ifdef HAVE_BTRFS_SUPPORT
+ if (fs->fstype && !strcmp(fs->fstype, "btrfs")) {
+ uint64_t default_id = btrfs_get_default_subvol_id(mnt_fs_get_target(fs));
+ char *val;
+ size_t len;
+
+ if (default_id == UINT64_MAX)
+ DBG(TAB, ul_debug("not found btrfs volume setting"));
+
+ else if (mnt_fs_get_option(fs, "subvolid", &val, &len) == 0) {
+ uint64_t subvol_id;
+
+ if (mnt_parse_offset(val, len, &subvol_id)) {
+ DBG(TAB, ul_debugobj(tb, "failed to parse subvolid="));
+ continue;
+ }
+ if (subvol_id != default_id)
+ continue;
+ }
+ }
+#endif /* HAVE_BTRFS_SUPPORT */
+ return fs;
+ }
+ if (mnt_fs_get_tag(fs, NULL, NULL) == 0)
+ ntags++;
+ }
+
+ if (!path || !tb->cache || !(cn = mnt_resolve_path(path, tb->cache)))
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup canonical SRCPATH: '%s'", cn));
+
+ nents = mnt_table_get_nents(tb);
+
+ /* canonicalized paths in struct libmnt_table */
+ if (ntags < nents) {
+ mnt_reset_iter(&itr, direction);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (mnt_fs_streq_srcpath(fs, cn))
+ return fs;
+ }
+ }
+
+ /* evaluated tag */
+ if (ntags) {
+ int rc = mnt_cache_read_tags(tb->cache, cn);
+
+ mnt_reset_iter(&itr, direction);
+
+ if (rc == 0) {
+ /* @path's TAGs are in the cache */
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ const char *t, *v;
+
+ if (mnt_fs_get_tag(fs, &t, &v))
+ continue;
+
+ if (mnt_cache_device_has_tag(tb->cache, cn, t, v))
+ return fs;
+ }
+ } else if (rc < 0 && errno == EACCES) {
+ /* @path is inaccessible, try evaluating all TAGs in @tb
+ * by udev symlinks -- this could be expensive on systems
+ * with a huge fstab/mtab */
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ const char *t, *v, *x;
+ if (mnt_fs_get_tag(fs, &t, &v))
+ continue;
+ x = mnt_resolve_tag(t, v, tb->cache);
+
+ /* both canonicalized, strcmp() is fine here */
+ if (x && strcmp(x, cn) == 0)
+ return fs;
+ }
+ }
+ }
+
+ /* non-canonicalized paths in struct libmnt_table */
+ if (ntags <= nents) {
+ mnt_reset_iter(&itr, direction);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (mnt_fs_is_netfs(fs) || mnt_fs_is_pseudofs(fs))
+ continue;
+ p = mnt_fs_get_srcpath(fs);
+ if (p)
+ p = mnt_resolve_path(p, tb->cache);
+
+ /* both canonicalized, strcmp() is fine here */
+ if (p && strcmp(p, cn) == 0)
+ return fs;
+ }
+ }
+
+ return NULL;
+}
+
+
+/**
+ * mnt_table_find_tag:
+ * @tb: tab pointer
+ * @tag: tag name (e.g "LABEL", "UUID", ...)
+ * @val: tag value
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * Try to lookup an entry in the given tab, the first attempt is to lookup by @tag and
+ * @val, for the second attempt the tag is evaluated (converted to the device
+ * name) and mnt_table_find_srcpath() is performed. The second attempt is not
+ * performed when @tb cache is not set (see mnt_table_set_cache()).
+
+ * Returns: a tab entry or NULL.
+ */
+struct libmnt_fs *mnt_table_find_tag(struct libmnt_table *tb, const char *tag,
+ const char *val, int direction)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs = NULL;
+
+ if (!tb || !tag || !*tag || !val)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup by TAG: %s %s", tag, val));
+
+ /* look up by TAG */
+ mnt_reset_iter(&itr, direction);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (fs->tagname && fs->tagval &&
+ strcmp(fs->tagname, tag) == 0 &&
+ strcmp(fs->tagval, val) == 0)
+ return fs;
+ }
+
+ if (tb->cache) {
+ /* look up by device name */
+ char *cn = mnt_resolve_tag(tag, val, tb->cache);
+ if (cn)
+ return mnt_table_find_srcpath(tb, cn, direction);
+ }
+ return NULL;
+}
+
+/**
+ * mnt_table_find_target_with_option:
+ * @tb: tab pointer
+ * @path: mountpoint directory
+ * @option: option name (e.g "subvol", "subvolid", ...)
+ * @val: option value or NULL
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * Try to lookup an entry in the given tab that matches combination of @path
+ * and @option. In difference to mnt_table_find_target(), only @path iteration
+ * is done. No lookup by device name, no canonicalization.
+ *
+ * Returns: a tab entry or NULL.
+ *
+ * Since: 2.28
+ */
+struct libmnt_fs *mnt_table_find_target_with_option(
+ struct libmnt_table *tb, const char *path,
+ const char *option, const char *val, int direction)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs = NULL;
+ char *optval = NULL;
+ size_t optvalsz = 0, valsz = val ? strlen(val) : 0;
+
+ if (!tb || !path || !*path || !option || !*option || !val)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup TARGET: '%s' with OPTION %s %s", path, option, val));
+
+ /* look up by native @target with OPTION */
+ mnt_reset_iter(&itr, direction);
+ while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (mnt_fs_streq_target(fs, path)
+ && mnt_fs_get_option(fs, option, &optval, &optvalsz) == 0
+ && (!val || (optvalsz == valsz
+ && strncmp(optval, val, optvalsz) == 0)))
+ return fs;
+ }
+ return NULL;
+}
+
+/**
+ * mnt_table_find_source:
+ * @tb: tab pointer
+ * @source: TAG or path
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * This is a high-level API for mnt_table_find_{srcpath,tag}. You needn't care
+ * about the @source format (device, LABEL, UUID, ...). This function parses
+ * the @source and calls mnt_table_find_tag() or mnt_table_find_srcpath().
+ *
+ * Returns: a tab entry or NULL.
+ */
+struct libmnt_fs *mnt_table_find_source(struct libmnt_table *tb,
+ const char *source, int direction)
+{
+ struct libmnt_fs *fs;
+ char *t = NULL, *v = NULL;
+
+ if (!tb)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup SOURCE: '%s'", source));
+
+ if (blkid_parse_tag_string(source, &t, &v) || !mnt_valid_tagname(t))
+ fs = mnt_table_find_srcpath(tb, source, direction);
+ else
+ fs = mnt_table_find_tag(tb, t, v, direction);
+
+ free(t);
+ free(v);
+
+ return fs;
+}
+
+/**
+ * mnt_table_find_pair
+ * @tb: tab pointer
+ * @source: TAG or path
+ * @target: mountpoint
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * This function is implemented by mnt_fs_match_source() and
+ * mnt_fs_match_target() functions. It means that this is more expensive than
+ * others mnt_table_find_* function, because every @tab entry is fully evaluated.
+ *
+ * Returns: a tab entry or NULL.
+ */
+struct libmnt_fs *mnt_table_find_pair(struct libmnt_table *tb, const char *source,
+ const char *target, int direction)
+{
+ struct libmnt_fs *fs = NULL;
+ struct libmnt_iter itr;
+
+ if (!tb || !target || !*target || !source || !*source)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup SOURCE: %s TARGET: %s", source, target));
+
+ mnt_reset_iter(&itr, direction);
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+
+ if (mnt_fs_match_target(fs, target, tb->cache) &&
+ mnt_fs_match_source(fs, source, tb->cache))
+ return fs;
+ }
+
+ return NULL;
+}
+
+/**
+ * mnt_table_find_devno
+ * @tb: /proc/self/mountinfo
+ * @devno: device number
+ * @direction: MNT_ITER_{FORWARD,BACKWARD}
+ *
+ * Note that zero could be a valid device number for the root pseudo filesystem (e.g.
+ * tmpfs).
+ *
+ * Returns: a tab entry or NULL.
+ */
+struct libmnt_fs *mnt_table_find_devno(struct libmnt_table *tb,
+ dev_t devno, int direction)
+{
+ struct libmnt_fs *fs = NULL;
+ struct libmnt_iter itr;
+
+ if (!tb)
+ return NULL;
+ if (direction != MNT_ITER_FORWARD && direction != MNT_ITER_BACKWARD)
+ return NULL;
+
+ DBG(TAB, ul_debugobj(tb, "lookup DEVNO: %d", (int) devno));
+
+ mnt_reset_iter(&itr, direction);
+
+ while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ if (mnt_fs_get_devno(fs) == devno)
+ return fs;
+ }
+
+ return NULL;
+}
+
+static char *remove_mountpoint_from_path(const char *path, const char *mnt)
+{
+ char *res;
+ const char *p;
+ size_t sz;
+
+ sz = strlen(mnt);
+ p = sz > 1 ? path + sz : path;
+
+ res = *p ? strdup(p) : strdup("/");
+ DBG(UTILS, ul_debug("%s fs-root is %s", path, res));
+ return res;
+}
+
+#ifdef HAVE_BTRFS_SUPPORT
+static int get_btrfs_fs_root(struct libmnt_table *tb, struct libmnt_fs *fs, char **root)
+{
+ char *vol = NULL, *p;
+ size_t sz, volsz = 0;
+
+ DBG(BTRFS, ul_debug("lookup for btrfs FS root"));
+ *root = NULL;
+
+ if (mnt_fs_get_option(fs, "subvolid", &vol, &volsz) == 0) {
+ char *target;
+ struct libmnt_fs *f;
+ char subvolidstr[sizeof(stringify_value(UINT64_MAX))];
+
+ DBG(BTRFS, ul_debug(" found subvolid=%s, checking", vol));
+
+ assert (volsz + 1 < sizeof(stringify_value(UINT64_MAX)));
+ memcpy(subvolidstr, vol, volsz);
+ subvolidstr[volsz] = '\0';
+
+ target = mnt_resolve_target(mnt_fs_get_target(fs), tb->cache);
+ if (!target)
+ goto err;
+
+ DBG(BTRFS, ul_debug(" trying target=%s subvolid=%s", target, subvolidstr));
+ f = mnt_table_find_target_with_option(tb, target,
+ "subvolid", subvolidstr,
+ MNT_ITER_BACKWARD);
+ if (!tb->cache)
+ free(target);
+ if (!f)
+ goto not_found;
+
+ /* Instead of set of BACKREF queries constructing subvol path
+ * corresponding to a particular subvolid, use the one in
+ * mountinfo. Kernel keeps subvol path up to date.
+ */
+ if (mnt_fs_get_option(f, "subvol", &vol, &volsz) != 0)
+ goto not_found;
+
+ } else if (mnt_fs_get_option(fs, "subvol", &vol, &volsz) != 0) {
+ /* If fstab entry does not contain "subvol", we have to
+ * check, whether btrfs has default subvolume defined.
+ */
+ uint64_t default_id;
+ char *target;
+ struct libmnt_fs *f;
+ char default_id_str[sizeof(stringify_value(UINT64_MAX))];
+
+ DBG(BTRFS, ul_debug(" subvolid/subvol not found, checking default"));
+
+ default_id = btrfs_get_default_subvol_id(mnt_fs_get_target(fs));
+ if (default_id == UINT64_MAX)
+ goto not_found;
+
+ /* Volume has default subvolume. Check if it matches to
+ * the one in mountinfo.
+ *
+ * Only kernel >= 4.2 reports subvolid. On older
+ * kernels, there is no reasonable way to detect which
+ * subvolume was mounted.
+ */
+ target = mnt_resolve_target(mnt_fs_get_target(fs), tb->cache);
+ if (!target)
+ goto err;
+
+ snprintf(default_id_str, sizeof(default_id_str), "%llu",
+ (unsigned long long int) default_id);
+
+ DBG(BTRFS, ul_debug(" trying target=%s default subvolid=%s",
+ target, default_id_str));
+
+ f = mnt_table_find_target_with_option(tb, target,
+ "subvolid", default_id_str,
+ MNT_ITER_BACKWARD);
+ if (!tb->cache)
+ free(target);
+ if (!f)
+ goto not_found;
+
+ /* Instead of set of BACKREF queries constructing
+ * subvol path, use the one in mountinfo. Kernel does
+ * the evaluation for us.
+ */
+ DBG(BTRFS, ul_debug("setting FS root: btrfs default subvolid = %s",
+ default_id_str));
+
+ if (mnt_fs_get_option(f, "subvol", &vol, &volsz) != 0)
+ goto not_found;
+ }
+
+ DBG(BTRFS, ul_debug(" using subvol=%s", vol));
+ sz = volsz;
+ if (*vol != '/')
+ sz++;
+ *root = malloc(sz + 1);
+ if (!*root)
+ goto err;
+ p = *root;
+ if (*vol != '/')
+ *p++ = '/';
+ memcpy(p, vol, volsz);
+ *(*root + sz) = '\0';
+ return 0;
+
+not_found:
+ DBG(BTRFS, ul_debug(" not found btrfs volume setting"));
+ return 1;
+err:
+ DBG(BTRFS, ul_debug(" error on btrfs volume setting evaluation"));
+ return errno ? -errno : -1;
+}
+#endif /* HAVE_BTRFS_SUPPORT */
+
+static const char *get_cifs_unc_subdir_path (const char *unc)
+{
+ /*
+ * 1 or more slash: %*[/]
+ * 1 or more non-slash: %*[^/]
+ * number of byte read: %n
+ */
+ int share_end = 0;
+ int r = sscanf(unc, "%*[/]%*[^/]%*[/]%*[^/]%n", &share_end);
+ if (r == EOF || share_end == 0)
+ return NULL;
+ return unc + share_end;
+}
+
+/*
+ * tb: /proc/self/mountinfo
+ * fs: filesystem
+ * mountflags: MS_BIND or 0
+ * fsroot: fs-root that will probably be used in the mountinfo file
+ * for @fs after mount(2)
+ *
+ * For btrfs subvolumes this function returns NULL, but @fsroot properly set.
+ *
+ * If @tb is NULL then defaults to '/'.
+ *
+ * Returns: entry from @tb that will be used as a source for @fs if the @fs is
+ * bindmount.
+ *
+ * Don't export to library API!
+ */
+struct libmnt_fs *mnt_table_get_fs_root(struct libmnt_table *tb,
+ struct libmnt_fs *fs,
+ unsigned long mountflags,
+ char **fsroot)
+{
+ char *root = NULL;
+ const char *mnt = NULL;
+ struct libmnt_fs *src_fs = NULL;
+
+ assert(fs);
+ assert(fsroot);
+
+ DBG(TAB, ul_debug("lookup fs-root for '%s'", mnt_fs_get_source(fs)));
+
+ if (tb && (mountflags & MS_BIND)) {
+ const char *src, *src_root;
+ char *xsrc = NULL;
+
+ DBG(TAB, ul_debug("fs-root for bind"));
+
+ src = xsrc = mnt_resolve_spec(mnt_fs_get_source(fs), tb->cache);
+ if (src) {
+ struct libmnt_fs *f = mnt_table_find_mountpoint(tb,
+ src, MNT_ITER_BACKWARD);
+ if (f)
+ mnt = mnt_fs_get_target(f);
+ }
+ if (mnt)
+ root = remove_mountpoint_from_path(src, mnt);
+
+ if (xsrc && !tb->cache) {
+ free(xsrc);
+ src = NULL;
+ }
+ if (!mnt)
+ goto err;
+
+ src_fs = mnt_table_find_target(tb, mnt, MNT_ITER_BACKWARD);
+ if (!src_fs) {
+ DBG(TAB, ul_debug("not found '%s' in mountinfo -- using default", mnt));
+ goto dflt;
+ }
+
+ /* It's possible that fstab_fs source is subdirectory on btrfs
+ * subvolume or another bind mount. For example:
+ *
+ * /dev/sdc /mnt/test btrfs subvol=/anydir
+ * /dev/sdc /mnt/test btrfs defaults
+ * /mnt/test/foo /mnt/test2 auto bind
+ *
+ * in this case, the root for /mnt/test2 will be /anydir/foo on
+ * /dev/sdc. It means we have to compose the final root from
+ * root and src_root.
+ */
+ src_root = mnt_fs_get_root(src_fs);
+
+ DBG(FS, ul_debugobj(fs, "source root: %s, source FS root: %s", root, src_root));
+
+ if (src_root && !startswith(root, src_root)) {
+ if (strcmp(root, "/") == 0) {
+ free(root);
+ root = strdup(src_root);
+ if (!root)
+ goto err;
+ } else {
+ char *tmp;
+ if (asprintf(&tmp, "%s%s", src_root, root) < 0)
+ goto err;
+ free(root);
+ root = tmp;
+ }
+ }
+ }
+
+#ifdef HAVE_BTRFS_SUPPORT
+ /*
+ * btrfs-subvolume mount -- get subvolume name and use it as a root-fs path
+ */
+ else if (tb && fs->fstype &&
+ (!strcmp(fs->fstype, "btrfs") || !strcmp(fs->fstype, "auto"))) {
+ if (get_btrfs_fs_root(tb, fs, &root) < 0)
+ goto err;
+ }
+#endif /* HAVE_BTRFS_SUPPORT */
+
+dflt:
+ if (!root) {
+ root = strdup("/");
+ if (!root)
+ goto err;
+ }
+ *fsroot = root;
+
+ DBG(TAB, ul_debug("FS root result: %s", root));
+
+ return src_fs;
+err:
+ free(root);
+ return NULL;
+}
+
+
+int __mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs,
+ const char *tgt_prefix)
+{
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs;
+
+ char *root = NULL;
+ char *src2 = NULL;
+ const char *src = NULL, *tgt = NULL;
+ char *xtgt = NULL, *tgt_buf = NULL;
+ int rc = 0;
+ dev_t devno = 0;
+
+ DBG(FS, ul_debugobj(fstab_fs, "mnt_table_is_fs_mounted: target=%s, source=%s",
+ mnt_fs_get_target(fstab_fs),
+ mnt_fs_get_source(fstab_fs)));
+
+ if (mnt_fs_is_swaparea(fstab_fs) || mnt_table_is_empty(tb)) {
+ DBG(FS, ul_debugobj(fstab_fs, "- ignore (swap or no data)"));
+ return 0;
+ }
+
+ if (is_mountinfo(tb)) {
+ /* @tb is mountinfo, so we can try to use fs-roots */
+ struct libmnt_fs *rootfs;
+ int flags = 0;
+
+ if (mnt_fs_get_option(fstab_fs, "bind", NULL, NULL) == 0 ||
+ mnt_fs_get_option(fstab_fs, "rbind", NULL, NULL) == 0)
+ flags = MS_BIND;
+
+ rootfs = mnt_table_get_fs_root(tb, fstab_fs, flags, &root);
+ if (rootfs) {
+ const char *fstype = mnt_fs_get_fstype(rootfs);
+
+ src = mnt_fs_get_srcpath(rootfs);
+ if (fstype && strncmp(fstype, "nfs", 3) == 0 && root) {
+ /* NFS stores the root at the end of the source */
+ src = src2 = strappend(src, root);
+ free(root);
+ root = NULL;
+ }
+ }
+ }
+
+ if (!src)
+ src = mnt_fs_get_source(fstab_fs);
+
+ if (src && tb->cache && !mnt_fs_is_pseudofs(fstab_fs))
+ src = mnt_resolve_spec(src, tb->cache);
+
+ if (src && root) {
+ struct stat st;
+
+ devno = mnt_fs_get_devno(fstab_fs);
+ if (!devno && stat(src, &st) == 0 && S_ISBLK(st.st_mode))
+ devno = st.st_rdev;
+ }
+
+ tgt = mnt_fs_get_target(fstab_fs);
+
+ if (!tgt || !src) {
+ DBG(FS, ul_debugobj(fstab_fs, "- ignore (no source/target)"));
+ goto done;
+ }
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+
+ DBG(FS, ul_debugobj(fstab_fs, "mnt_table_is_fs_mounted: src=%s, tgt=%s, root=%s", src, tgt, root));
+
+ while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+
+ int eq = mnt_fs_streq_srcpath(fs, src);
+
+ if (!eq && devno && mnt_fs_get_devno(fs) == devno)
+ eq = 1;
+
+ if (!eq) {
+ /* The source does not match. Maybe the source is a loop
+ * device backing file.
+ */
+ uint64_t offset = 0;
+ char *val;
+ size_t len;
+ int flags = 0;
+
+ if (!mnt_fs_get_srcpath(fs) ||
+ !startswith(mnt_fs_get_srcpath(fs), "/dev/loop"))
+ continue; /* does not look like loopdev */
+
+ if (mnt_fs_get_option(fstab_fs, "offset", &val, &len) == 0) {
+ if (mnt_parse_offset(val, len, &offset)) {
+ DBG(FS, ul_debugobj(fstab_fs, "failed to parse offset="));
+ continue;
+ }
+ flags = LOOPDEV_FL_OFFSET;
+ }
+
+ DBG(FS, ul_debugobj(fs, "checking for loop: src=%s", mnt_fs_get_srcpath(fs)));
+#if __linux__
+ if (!loopdev_is_used(mnt_fs_get_srcpath(fs), src, offset, 0, flags))
+ continue;
+
+ DBG(FS, ul_debugobj(fs, "used loop"));
+#endif
+ }
+
+ if (root) {
+ const char *fstype = mnt_fs_get_fstype(fs);
+
+ if (fstype && (strcmp(fstype, "cifs") == 0 ||
+ strcmp(fstype, "smb3") == 0)) {
+
+ const char *sub = get_cifs_unc_subdir_path(src);
+ const char *r = mnt_fs_get_root(fs);
+
+ if (!sub || !r || (!streq_paths(sub, r) &&
+ !streq_paths("/", r)))
+ continue;
+ } else {
+ const char *r = mnt_fs_get_root(fs);
+ if (!r || strcmp(r, root) != 0)
+ continue;
+ }
+ }
+
+ /*
+ * Compare target, try to minimize the number of situations when we
+ * need to canonicalize the path to avoid readlink() on
+ * mountpoints.
+ */
+ if (!xtgt) {
+ if (tgt_prefix) {
+ const char *p = *tgt == '/' ? tgt + 1 : tgt;
+ if (!*p)
+ tgt = tgt_prefix; /* target is '/' */
+ else {
+ if (asprintf(&tgt_buf, "%s/%s", tgt_prefix, p) <= 0) {
+ rc = -ENOMEM;
+ goto done;
+ }
+ tgt = tgt_buf;
+ }
+ }
+
+ if (mnt_fs_streq_target(fs, tgt))
+ break;
+ if (tb->cache)
+ xtgt = mnt_resolve_path(tgt, tb->cache);
+ }
+ if (xtgt && mnt_fs_streq_target(fs, xtgt))
+ break;
+ }
+
+ if (fs)
+ rc = 1; /* success */
+done:
+ free(root);
+ free(tgt_buf);
+
+ DBG(TAB, ul_debugobj(tb, "mnt_table_is_fs_mounted: %s [rc=%d]", src, rc));
+ free(src2);
+ return rc;
+}
+
+/**
+ * mnt_table_is_fs_mounted:
+ * @tb: /proc/self/mountinfo file
+ * @fstab_fs: /etc/fstab entry
+ *
+ * Checks if the @fstab_fs entry is already in the @tb table. The "swap" is
+ * ignored. This function explicitly compares the source, target and root of the
+ * filesystems.
+ *
+ * Note that source and target are canonicalized only if a cache for @tb is
+ * defined (see mnt_table_set_cache()). The target canonicalization may
+ * trigger automount on autofs mountpoints!
+ *
+ * Don't use it if you want to know if a device is mounted, just use
+ * mnt_table_find_source() on the device.
+ *
+ * This function is designed mostly for "mount -a".
+ *
+ * Returns: 0 or 1
+ */
+int mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs)
+{
+ return __mnt_table_is_fs_mounted(tb, fstab_fs, NULL);
+}
+
+
+#ifdef TEST_PROGRAM
+#include "pathnames.h"
+
+static int parser_errcb(struct libmnt_table *tb, const char *filename, int line)
+{
+ fprintf(stderr, "%s:%d: parse error\n", filename, line);
+
+ return 1; /* all errors are recoverable -- this is the default */
+}
+
+static struct libmnt_table *create_table(const char *file, int comments)
+{
+ struct libmnt_table *tb;
+
+ if (!file)
+ return NULL;
+ tb = mnt_new_table();
+ if (!tb)
+ goto err;
+
+ mnt_table_enable_comments(tb, comments);
+ mnt_table_set_parser_errcb(tb, parser_errcb);
+
+ if (mnt_table_parse_file(tb, file) != 0)
+ goto err;
+ return tb;
+err:
+ fprintf(stderr, "%s: parsing failed\n", file);
+ mnt_unref_table(tb);
+ return NULL;
+}
+
+static int test_copy_fs(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb;
+ struct libmnt_fs *fs;
+ int rc = -1;
+
+ tb = create_table(argv[1], FALSE);
+ if (!tb)
+ return -1;
+
+ fs = mnt_table_find_target(tb, "/", MNT_ITER_FORWARD);
+ if (!fs)
+ goto done;
+
+ printf("ORIGINAL:\n");
+ mnt_fs_print_debug(fs, stdout);
+
+ fs = mnt_copy_fs(NULL, fs);
+ if (!fs)
+ goto done;
+
+ printf("COPY:\n");
+ mnt_fs_print_debug(fs, stdout);
+ mnt_unref_fs(fs);
+ rc = 0;
+done:
+ mnt_unref_table(tb);
+ return rc;
+}
+
+static int test_parse(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb = NULL;
+ struct libmnt_iter *itr = NULL;
+ struct libmnt_fs *fs;
+ int rc = -1;
+ int parse_comments = FALSE;
+
+ if (argc == 3 && !strcmp(argv[2], "--comments"))
+ parse_comments = TRUE;
+
+ tb = create_table(argv[1], parse_comments);
+ if (!tb)
+ return -1;
+
+ itr = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!itr)
+ goto done;
+
+ if (mnt_table_get_intro_comment(tb))
+ fprintf(stdout, "Initial comment:\n\"%s\"\n",
+ mnt_table_get_intro_comment(tb));
+
+ while(mnt_table_next_fs(tb, itr, &fs) == 0)
+ mnt_fs_print_debug(fs, stdout);
+
+ if (mnt_table_get_trailing_comment(tb))
+ fprintf(stdout, "Trailing comment:\n\"%s\"\n",
+ mnt_table_get_trailing_comment(tb));
+ rc = 0;
+done:
+ mnt_free_iter(itr);
+ mnt_unref_table(tb);
+ return rc;
+}
+
+static int test_find_idx(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb;
+ struct libmnt_fs *fs = NULL;
+ struct libmnt_cache *mpc = NULL;
+ const char *file, *what;
+ int rc = -1;
+
+ if (argc != 3) {
+ fprintf(stderr, "try --help\n");
+ return -EINVAL;
+ }
+
+ file = argv[1], what = argv[2];
+
+ tb = create_table(file, FALSE);
+ if (!tb)
+ goto done;
+
+ /* create a cache for canonicalized paths */
+ mpc = mnt_new_cache();
+ if (!mpc)
+ goto done;
+ mnt_table_set_cache(tb, mpc);
+ mnt_unref_cache(mpc);
+
+ fs = mnt_table_find_target(tb, what, MNT_ITER_BACKWARD);
+
+ if (!fs)
+ fprintf(stderr, "%s: not found '%s'\n", file, what);
+ else {
+ int idx = mnt_table_find_fs(tb, fs);
+
+ if (idx < 1)
+ fprintf(stderr, "%s: not found '%s' fs pointer", file, what);
+ else {
+ printf("%s index is %d\n", what, idx);
+ rc = 0;
+ }
+ }
+done:
+ mnt_unref_table(tb);
+ return rc;
+}
+
+static int test_find(struct libmnt_test *ts, int argc, char *argv[], int dr)
+{
+ struct libmnt_table *tb;
+ struct libmnt_fs *fs = NULL;
+ struct libmnt_cache *mpc = NULL;
+ const char *file, *find, *what;
+ int rc = -1;
+
+ if (argc != 4) {
+ fprintf(stderr, "try --help\n");
+ return -EINVAL;
+ }
+
+ file = argv[1], find = argv[2], what = argv[3];
+
+ tb = create_table(file, FALSE);
+ if (!tb)
+ goto done;
+
+ /* create a cache for canonicalized paths */
+ mpc = mnt_new_cache();
+ if (!mpc)
+ goto done;
+ mnt_table_set_cache(tb, mpc);
+ mnt_unref_cache(mpc);
+
+ if (strcasecmp(find, "source") == 0)
+ fs = mnt_table_find_source(tb, what, dr);
+ else if (strcasecmp(find, "target") == 0)
+ fs = mnt_table_find_target(tb, what, dr);
+
+ if (!fs)
+ fprintf(stderr, "%s: not found %s '%s'\n", file, find, what);
+ else {
+ mnt_fs_print_debug(fs, stdout);
+ rc = 0;
+ }
+done:
+ mnt_unref_table(tb);
+ return rc;
+}
+
+static int test_find_bw(struct libmnt_test *ts, int argc, char *argv[])
+{
+ return test_find(ts, argc, argv, MNT_ITER_BACKWARD);
+}
+
+static int test_find_fw(struct libmnt_test *ts, int argc, char *argv[])
+{
+ return test_find(ts, argc, argv, MNT_ITER_FORWARD);
+}
+
+static int test_find_pair(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb;
+ struct libmnt_fs *fs;
+ struct libmnt_cache *mpc = NULL;
+ int rc = -1;
+
+ tb = create_table(argv[1], FALSE);
+ if (!tb)
+ return -1;
+ mpc = mnt_new_cache();
+ if (!mpc)
+ goto done;
+ mnt_table_set_cache(tb, mpc);
+ mnt_unref_cache(mpc);
+
+ fs = mnt_table_find_pair(tb, argv[2], argv[3], MNT_ITER_FORWARD);
+ if (!fs)
+ goto done;
+
+ mnt_fs_print_debug(fs, stdout);
+ rc = 0;
+done:
+ mnt_unref_table(tb);
+ return rc;
+}
+
+static int test_find_mountpoint(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb;
+ struct libmnt_fs *fs;
+ struct libmnt_cache *mpc = NULL;
+ int rc = -1;
+
+ tb = mnt_new_table_from_file(_PATH_PROC_MOUNTINFO);
+ if (!tb)
+ return -1;
+ mpc = mnt_new_cache();
+ if (!mpc)
+ goto done;
+ mnt_table_set_cache(tb, mpc);
+ mnt_unref_cache(mpc);
+
+ fs = mnt_table_find_mountpoint(tb, argv[1], MNT_ITER_BACKWARD);
+ if (!fs)
+ goto done;
+
+ mnt_fs_print_debug(fs, stdout);
+ rc = 0;
+done:
+ mnt_unref_table(tb);
+ return rc;
+}
+
+static int test_is_mounted(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb = NULL, *fstab = NULL;
+ struct libmnt_fs *fs;
+ struct libmnt_iter *itr = NULL;
+ struct libmnt_cache *mpc = NULL;
+ int writable = 0;
+ const char *path = NULL;
+
+ if (mnt_has_regular_mtab(&path, &writable) == 1 && writable == 0)
+ tb = mnt_new_table_from_file(path);
+ else
+ tb = mnt_new_table_from_file("/proc/self/mountinfo");
+
+ if (!tb) {
+ fprintf(stderr, "failed to parse mountinfo\n");
+ return -1;
+ }
+
+ fstab = create_table(argv[1], FALSE);
+ if (!fstab)
+ goto done;
+
+ itr = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!itr)
+ goto done;
+
+ mpc = mnt_new_cache();
+ if (!mpc)
+ goto done;
+ mnt_table_set_cache(tb, mpc);
+ mnt_unref_cache(mpc);
+
+ while (mnt_table_next_fs(fstab, itr, &fs) == 0) {
+ if (mnt_table_is_fs_mounted(tb, fs))
+ printf("%s already mounted on %s\n",
+ mnt_fs_get_source(fs),
+ mnt_fs_get_target(fs));
+ else
+ printf("%s not mounted on %s\n",
+ mnt_fs_get_source(fs),
+ mnt_fs_get_target(fs));
+ }
+
+done:
+ mnt_unref_table(tb);
+ mnt_unref_table(fstab);
+ mnt_free_iter(itr);
+ return 0;
+}
+
+/* returns 0 if @a and @b targets are the same */
+static int test_uniq_cmp(struct libmnt_table *tb __attribute__((__unused__)),
+ struct libmnt_fs *a,
+ struct libmnt_fs *b)
+{
+ assert(a);
+ assert(b);
+
+ return mnt_fs_streq_target(a, mnt_fs_get_target(b)) ? 0 : 1;
+}
+
+static int test_uniq(struct libmnt_test *ts, int argc, char *argv[])
+{
+ struct libmnt_table *tb;
+ int rc = -1;
+
+ if (argc != 2) {
+ fprintf(stderr, "try --help\n");
+ return -EINVAL;
+ }
+
+ tb = create_table(argv[1], FALSE);
+ if (!tb)
+ goto done;
+
+ if (mnt_table_uniq_fs(tb, 0, test_uniq_cmp) == 0) {
+ struct libmnt_iter *itr = mnt_new_iter(MNT_ITER_FORWARD);
+ struct libmnt_fs *fs;
+ if (!itr)
+ goto done;
+ while (mnt_table_next_fs(tb, itr, &fs) == 0)
+ mnt_fs_print_debug(fs, stdout);
+ mnt_free_iter(itr);
+ rc = 0;
+ }
+done:
+ mnt_unref_table(tb);
+ return rc;
+}
+
+
+int main(int argc, char *argv[])
+{
+ struct libmnt_test tss[] = {
+ { "--parse", test_parse, "<file> [--comments] parse and print tab" },
+ { "--find-forward", test_find_fw, "<file> <source|target> <string>" },
+ { "--find-backward", test_find_bw, "<file> <source|target> <string>" },
+ { "--uniq-target", test_uniq, "<file>" },
+ { "--find-pair", test_find_pair, "<file> <source> <target>" },
+ { "--find-fs", test_find_idx, "<file> <target>" },
+ { "--find-mountpoint", test_find_mountpoint, "<path>" },
+ { "--copy-fs", test_copy_fs, "<file> copy root FS from the file" },
+ { "--is-mounted", test_is_mounted, "<fstab> check what from fstab is already mounted" },
+ { NULL }
+ };
+
+ return mnt_run_test(tss, argc, argv);
+}
+
+#endif /* TEST_PROGRAM */