#ifndef UTIL_LINUX_MOUNT_API_UTILS
#define UTIL_LINUX_MOUNT_API_UTILS
-#if defined(HAVE_MOUNTFD_API) && defined(HAVE_LINUX_MOUNT_H)
-
-#include <sys/syscall.h>
+#ifdef HAVE_LINUX_MOUNT_H
+#include <sys/mount.h>
#include <linux/mount.h>
+#include <sys/syscall.h>
+#include <inttypes.h>
+
+/*
+ * File descritors based mount API
+ */
+#ifdef HAVE_MOUNTFD_API
/* Accepted by both open_tree() and mount_setattr(). */
#ifndef AT_RECURSIVE
}
#endif
-#endif /* HAVE_MOUNTFD_API && HAVE_LINUX_MOUNT_H */
-#endif /* UTIL_LINUX_MOUNT_API_UTILS */
+#endif /* HAVE_MOUNTFD_API */
+
+/*
+ * statmount() and listmount()
+ */
+#ifdef HAVE_STATMOUNT_API
+
+#ifndef MNT_ID_REQ_SIZE_VER0
+# define MNT_ID_REQ_SIZE_VER0 24 /* sizeof first published struct */
+#endif
+#ifndef MNT_ID_REQ_SIZE_VER1
+# define MNT_ID_REQ_SIZE_VER1 32 /* sizeof second published struct */
+#endif
+
+/*
+ * The structs mnt_id_req and statmount may differ between kernel versions, so
+ * we must ensure that the structs contain everything we need. For now (during
+ * development), it seems best to define local copies of the structs to avoid
+ * relying on installed kernel headers and to avoid a storm of #ifdefs.
+ */
+
+/*
+ * listmount() and statmount() request
+ */
+struct ul_mnt_id_req {
+ uint32_t size;
+ uint32_t spare;
+ uint64_t mnt_id;
+ uint64_t param;
+ uint64_t mnt_ns_id;
+};
+
+/*
+ * Please note that due to the variable length of the statmount buffer, the
+ * struct cannot be versioned by size (like struct mnt_id_req).
+ */
+struct ul_statmount {
+ uint32_t size; /* Total size, including strings */
+ uint32_t mnt_opts; /* [str] Mount options of the mount */
+ uint64_t mask; /* What results were written */
+ uint32_t sb_dev_major; /* Device ID */
+ uint32_t sb_dev_minor;
+ uint64_t sb_magic; /* ..._SUPER_MAGIC */
+ uint32_t sb_flags; /* SB_{RDONLY,SYNCHRONOUS,DIRSYNC,LAZYTIME} */
+ uint32_t fs_type; /* [str] Filesystem type */
+ uint64_t mnt_id; /* Unique ID of mount */
+ uint64_t mnt_parent_id; /* Unique ID of parent (for root == mnt_id) */
+ uint32_t mnt_id_old; /* Reused IDs used in proc/.../mountinfo */
+ uint32_t mnt_parent_id_old;
+ uint64_t mnt_attr; /* MOUNT_ATTR_... */
+ uint64_t mnt_propagation; /* MS_{SHARED,SLAVE,PRIVATE,UNBINDABLE} */
+ uint64_t mnt_peer_group; /* ID of shared peer group */
+ uint64_t mnt_master; /* Mount receives propagation from this ID */
+ uint64_t propagate_from; /* Propagation from in current namespace */
+ uint32_t mnt_root; /* [str] Root of mount relative to root of fs */
+ uint32_t mnt_point; /* [str] Mountpoint relative to current root */
+ uint64_t mnt_ns_id; /* ID of the mount namespace */
+ uint64_t __spare2[49];
+ char str[]; /* Variable size part containing strings */
+};
+
+/* sb_flags (defined in kernel include/linux/fs.h) */
+#ifndef SB_RDONLY
+# define SB_RDONLY BIT(0) /* Mount read-only */
+# define SB_NOSUID BIT(1) /* Ignore suid and sgid bits */
+# define SB_NODEV BIT(2) /* Disallow access to device special files */
+# define SB_NOEXEC BIT(3) /* Disallow program execution */
+# define SB_SYNCHRONOUS BIT(4) /* Writes are synced at once */
+# define SB_MANDLOCK BIT(6) /* Allow mandatory locks on an FS */
+# define SB_DIRSYNC BIT(7) /* Directory modifications are synchronous */
+# define SB_NOATIME BIT(10) /* Do not update access times. */
+# define SB_NODIRATIME BIT(11) /* Do not update directory access times */
+# define SB_SILENT BIT(15)
+# define SB_POSIXACL BIT(16) /* Supports POSIX ACLs */
+# define SB_INLINECRYPT BIT(17) /* Use blk-crypto for encrypted files */
+# define SB_KERNMOUNT BIT(22) /* this is a kern_mount call */
+# define SB_I_VERSION BIT(23) /* Update inode I_version field */
+# define SB_LAZYTIME BIT(25) /* Update the on-disk [acm]times lazily */
+#endif
+
+/*
+ * @mask bits for statmount(2)
+ */
+#ifndef STATMOUNT_SB_BASIC
+# define STATMOUNT_SB_BASIC 0x00000001U /* Want/got sb_... */
+#endif
+#ifndef STATMOUNT_MNT_BASIC
+# define STATMOUNT_MNT_BASIC 0x00000002U /* Want/got mnt_... */
+#endif
+#ifndef STATMOUNT_PROPAGATE_FROM
+# define STATMOUNT_PROPAGATE_FROM 0x00000004U /* Want/got propagate_from */
+#endif
+#ifndef STATMOUNT_MNT_ROOT
+# define STATMOUNT_MNT_ROOT 0x00000008U /* Want/got mnt_root */
+#endif
+#ifndef STATMOUNT_MNT_POINT
+# define STATMOUNT_MNT_POINT 0x00000010U /* Want/got mnt_point */
+#endif
+#ifndef STATMOUNT_FS_TYPE
+# define STATMOUNT_FS_TYPE 0x00000020U /* Want/got fs_type */
+#endif
+#ifndef STATMOUNT_MNT_NS_ID
+# define STATMOUNT_MNT_NS_ID 0x00000040U /* Want/got mnt_ns_id */
+#endif
+#ifndef STATMOUNT_MNT_OPTS
+# define STATMOUNT_MNT_OPTS 0x00000080U /* Want/got mnt_opts */
+#endif
+/*
+ * Special @mnt_id values that can be passed to listmount
+ */
+#ifdef LSMT_ROOT
+# define LSMT_ROOT 0xffffffffffffffff /* root mount */
+#endif
+
+#ifndef LISTMOUNT_REVERS
+# define LISTMOUNT_REVERSE BIT(0) /* List later mounts first */
+#endif
+
+#if defined(SYS_statmount)
+static inline int ul_statmount(uint64_t mnt_id,
+ uint64_t ns_id,
+ uint64_t mask,
+ struct ul_statmount *buf,
+ size_t bufsize, unsigned int flags)
+{
+ struct ul_mnt_id_req req = {
+ .size = MNT_ID_REQ_SIZE_VER1,
+ .mnt_id = mnt_id,
+ .param = mask,
+ .mnt_ns_id = ns_id
+ };
+
+ return syscall(SYS_statmount, &req, buf, bufsize, flags);
+}
+#endif
+
+#if defined(SYS_listmount)
+static inline ssize_t ul_listmount(uint64_t mnt_id,
+ uint64_t ns_id,
+ uint64_t last_mnt_id,
+ uint64_t list[], size_t num,
+ unsigned int flags)
+{
+ struct ul_mnt_id_req req = {
+ .size = MNT_ID_REQ_SIZE_VER1,
+ .mnt_id = mnt_id,
+ .param = last_mnt_id,
+ .mnt_ns_id = ns_id
+ };
+
+ return syscall(SYS_listmount, &req, list, num, flags);
+}
+#endif
+
+/* This is a version of statmount() that reallocates @buf to be large enough to
+ * store data for the requested @id. This function never deallocates; it is the
+ * caller's responsibility.
+ */
+static inline int sys_statmount(uint64_t id,
+ uint64_t ns_id,
+ uint64_t mask,
+ struct ul_statmount **buf,
+ size_t *bufsiz,
+ unsigned int flags)
+{
+ size_t sz;
+ int rc = 0;
+
+ if (!buf || !bufsiz)
+ return -EINVAL;
+
+ sz = *bufsiz;
+ if (!sz)
+ sz = 32 * 1024;
+
+ do {
+ if (sz > *bufsiz) {
+ struct ul_statmount *tmp = realloc(*buf, sz);
+ if (!tmp)
+ return -ENOMEM;
+ *buf = tmp;
+ *bufsiz = sz;
+ }
+
+ errno = 0;
+ rc = ul_statmount(id, ns_id, mask, *buf, *bufsiz, flags);
+ if (!rc)
+ break;
+ if (errno != EOVERFLOW)
+ break;
+ if (sz >= SIZE_MAX / 2)
+ break;
+ sz <<= 1;
+ } while (rc);
+
+ return rc;
+}
+
+#endif /* HAVE_STATMOUNT_API */
+
+#endif /* HAVE_LINUX_MOUNT_H */
+
+#endif /* UTIL_LINUX_MOUNT_API_UTILS */
projects / thirdparty / util-linux.git / commitdiff
