From: Karel Zak <kzak@redhat.com>
Date: Wed, 14 Aug 2024 14:28:48 +0000 (+0200)
Subject: libmount: add API to read ID by statx()
X-Git-Tag: v2.42-start~97^2~32
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2dfadc248ceb4f1874756cd11a93b268a6e553e2;p=thirdparty%2Futil-linux.git

libmount: add API to read ID by statx()

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libmount/docs/libmount-sections.txt b/libmount/docs/libmount-sections.txt
index a8a503144..b72229c58 100644
--- a/libmount/docs/libmount-sections.txt
+++ b/libmount/docs/libmount-sections.txt
@@ -430,6 +430,7 @@ mnt_get_mtab_path
 mnt_get_swaps_path
 mnt_guess_system_root
 mnt_has_regular_mtab
+mnt_id_from_path
 mnt_mangle
 mnt_match_fstype
 mnt_tag_is_valid
diff --git a/libmount/src/libmount.h.in b/libmount/src/libmount.h.in
index 90f6a66c0..146240630 100644
--- a/libmount/src/libmount.h.in
+++ b/libmount/src/libmount.h.in
@@ -369,6 +369,8 @@ extern char *mnt_get_mountpoint(const char *path)
 extern int mnt_guess_system_root(dev_t devno, struct libmnt_cache *cache, char **path)
 			__ul_attribute__((nonnull(3)));
 
+extern int mnt_id_from_path(const char *path, uint64_t *uniq_id, int *id);
+
 /* cache.c */
 extern struct libmnt_cache *mnt_new_cache(void)
 			__ul_attribute__((warn_unused_result));
diff --git a/libmount/src/libmount.sym b/libmount/src/libmount.sym
index cdd76ba32..af7b2ac21 100644
--- a/libmount/src/libmount.sym
+++ b/libmount/src/libmount.sym
@@ -386,4 +386,5 @@ MOUNT_2_41 {
 	mnt_fs_get_uniq_id;
 	mnt_fs_get_parent_uniq_id;
 	mnt_fs_set_uniq_id;
+	mnt_id_from_path;
 } MOUNT_2_40;
diff --git a/libmount/src/mountP.h b/libmount/src/mountP.h
index 370bcd9e7..b1374ceb2 100644
--- a/libmount/src/mountP.h
+++ b/libmount/src/mountP.h
@@ -136,6 +136,8 @@ extern int mnt_is_path(const char *target);
 extern int mnt_tmptgt_unshare(int *old_ns_fd);
 extern int mnt_tmptgt_cleanup(int old_ns_fd);
 
+extern int mnt_id_from_fd(int fd, uint64_t *uniq_id, int *id);
+
 /* tab.c */
 extern int is_mountinfo(struct libmnt_table *tb);
 extern int mnt_table_set_parser_fltrcb(	struct libmnt_table *tb,
diff --git a/libmount/src/utils.c b/libmount/src/utils.c
index 94a877cf0..e5e376629 100644
--- a/libmount/src/utils.c
+++ b/libmount/src/utils.c
@@ -266,6 +266,63 @@ int mnt_is_readonly(const char *path)
 	return 0;
 }
 
+static int get_mnt_id(	int fd, const char *path,
+			uint64_t *uniq_id, int *id)
+{
+#if defined(HAVE_STATX) && defined(HAVE_STRUCT_STATX) && defined(HAVE_STRUCT_STATX_STX_MNT_ID)
+	int rc;
+	struct statx sx = { 0 };
+	int flags = AT_STATX_DONT_SYNC | AT_NO_AUTOMOUNT;
+
+	if (!path || !*path)
+		flags |= AT_EMPTY_PATH;
+
+	if (id) {
+		rc = statx(fd, path ? path : "", flags,
+				STATX_MNT_ID, &sx);
+		if (rc)
+			return rc;
+		*id = sx.stx_mnt_id;
+	}
+	if (uniq_id) {
+		errno = 0;
+		rc = statx(fd, path ? path : "", flags,
+				STATX_MNT_ID_UNIQUE, &sx);
+
+		if (rc && errno == EINVAL)
+			return -ENOSYS;		/* *_ID_UNIQUE unsupported? */
+		if (rc)
+			return rc;
+		*uniq_id = sx.stx_mnt_id;
+	}
+	return 0;
+#else
+	return -ENOSYS;
+#endif
+}
+
+int mnt_id_from_fd(int fd, uint64_t *uniq_id, int *id)
+{
+	return get_mnt_id(fd, NULL, uniq_id, id);
+}
+
+/**
+ * mnt_id_from_path:
+ * @path: mountpoint
+ * @uniq_id: returns STATX_MNT_ID_UNIQUE
+ * @id: returns STATX_MNT_ID
+ *
+ * Converts @path to ID.
+ *
+ * Returns: 0 on success, <0 on error
+ *
+ * Since: 2.41
+ */
+int mnt_id_from_path(const char *path, uint64_t *uniq_id, int *id)
+{
+	return get_mnt_id(-1, path, uniq_id, id);
+}
+
 /**
  * mnt_mangle:
  * @str: string