STATX(2)                   Linux Programmer's Manual                  STATX(2)

       statx - get file status (extended)

       #include <sys/types.h>
       #include <sys/stat.h>
       #include <unistd.h>
       #include <fcntl.h>           /* Definition of AT_* constants */

       int statx(int dirfd, const char *pathname, int flags,
                 unsigned int mask, struct statx *statxbuf);

       Note: There is no glibc wrapper for statx(); see NOTES.

       This  function returns information about a file, storing it in the buf-
       fer pointed to by statxbuf.  The returned buffer is a structure of  the
       following type:

           struct statx {
               __u32 stx_mask;        /* Mask of bits indicating
                                         filled fields */
               __u32 stx_blksize;     /* Block size for filesystem I/O */
               __u64 stx_attributes;  /* Extra file attribute indicators */
               __u32 stx_nlink;       /* Number of hard links */
               __u32 stx_uid;         /* User ID of owner */
               __u32 stx_gid;         /* Group ID of owner */
               __u16 stx_mode;        /* File type and mode */
               __u64 stx_ino;         /* Inode number */
               __u64 stx_size;        /* Total size in bytes */
               __u64 stx_blocks;      /* Number of 512B blocks allocated */
               __u64 stx_attributes_mask;
                                      /* Mask to show what's supported
                                         in stx_attributes */

               /* The following fields are file timestamps */
               struct statx_timestamp stx_atime;  /* Last access */
               struct statx_timestamp stx_btime;  /* Creation */
               struct statx_timestamp stx_ctime;  /* Last status change */
               struct statx_timestamp stx_mtime;  /* Last modification */

               /* If this file represents a device, then the next two
                  fields contain the ID of the device */
               __u32 stx_rdev_major;  /* Major ID */
               __u32 stx_rdev_minor;  /* Minor ID */

               /* The next two fields contain the ID of the device
                  containing the filesystem where the file resides */
               __u32 stx_dev_major;   /* Major ID */
               __u32 stx_dev_minor;   /* Minor ID */

       The file timestamps are structures of the following type:

           struct statx_timestamp {
               __s64 tv_sec;    /* Seconds since the Epoch (UNIX time) */
               __u32 tv_nsec;   /* Nanoseconds since tv_sec */

       (Note that reserved space and padding is omitted.)

   Invoking statx():
       To  access  a  file's  status,  no permissions are required on the file
       itself, but in the case of statx() with a  pathname,  execute  (search)
       permission  is required on all of the directories in pathname that lead
       to the file.

       statx() uses pathname, dirfd, and flags to identify the target file  in
       one of the following ways:

       An absolute pathname
              If pathname begins with a slash, then it is an absolute pathname
              that identifies  the  target  file.   In  this  case,  dirfd  is

       A relative pathname
              If  pathname is a string that begins with a character other than
              a slash and dirfd is AT_FDCWD, then pathname is a relative path-
              name that is interpreted relative to the process's current work-
              ing directory.

       A directory-relative pathname
              If pathname is a string that begins with a character other  than
              a  slash  and dirfd is a file descriptor that refers to a direc-
              tory, then pathname is a relative pathname that  is  interpreted
              relative to the directory referred to by dirfd.

       By file descriptor
              If  pathname  is  an  empty string and the AT_EMPTY_PATH flag is
              specified in flags (see below), then the target file is the  one
              referred to by the file descriptor dirfd.

       flags  can  be  used to influence a pathname-based lookup.  A value for
       flags is constructed by ORing together zero or more  of  the  following

              If  pathname is an empty string, operate on the file referred to
              by dirfd (which may have been obtained using the open(2)  O_PATH
              flag).   In  this case, dirfd can refer to any type of file, not
              just a directory.

              If dirfd is AT_FDCWD, the call operates on the  current  working

              This  flag  is  Linux-specific; define _GNU_SOURCE to obtain its

              Don't automount the terminal ("basename") component of  pathname
              if  it  is  a directory that is an automount point.  This allows
              the caller to gather attributes of an  automount  point  (rather
              than  the  location  it  would mount).  This flag can be used in
              tools that scan directories to prevent  mass-automounting  of  a
              directory  of automount points.  The AT_NO_AUTOMOUNT flag has no
              effect if the mount point has already been mounted  over.   This
              flag is Linux-specific; define _GNU_SOURCE to obtain its defini-

              If pathname is a symbolic link, do not dereference  it:  instead
              return information about the link itself, like lstat(2).

       flags can also be used to control what sort of synchronization the ker-
       nel will do when querying a file on a remote filesystem.  This is  done
       by ORing in one of the following values:

              Do  whatever stat(2) does.  This is the default and is very much

              Force the attributes to be synchronized with the  server.   This
              may  require  that a network filesystem perform a data writeback
              to get the timestamps correct.

              Don't synchronize anything, but rather just  take  whatever  the
              system  has cached if possible.  This may mean that the informa-
              tion returned is approximate, but, on a network  filesystem,  it
              may not involve a round trip to the server - even if no lease is

       The mask argument to statx() is used to tell the  kernel  which  fields
       the  caller  is interested in.  mask is an ORed combination of the fol-
       lowing constants:

           STATX_TYPE          Want stx_mode & S_IFMT
           STATX_MODE          Want stx_mode & ~S_IFMT
           STATX_NLINK         Want stx_nlink
           STATX_UID           Want stx_uid
           STATX_GID           Want stx_gid
           STATX_ATIME         Want stx_atime
           STATX_MTIME         Want stx_mtime
           STATX_CTIME         Want stx_ctime
           STATX_INO           Want stx_ino
           STATX_SIZE          Want stx_size
           STATX_BLOCKS        Want stx_blocks
           STATX_BASIC_STATS   [All of the above]
           STATX_BTIME         Want stx_btime
           STATX_ALL           [All currently available fields]

       Note that the kernel does not reject values  in  mask  other  than  the
       above.   Instead,  it  simply  informs the caller which values are sup-
       ported by this kernel and  filesystem  via  the  statx.stx_mask  field.
       Therefore, do not simply set mask to UINT_MAX (all bits set), as one or
       more bits may, in the future, be used to specify an  extension  to  the

   The returned information
       The  status  information  for  the target file is returned in the statx
       structure pointed to by statxbuf.  Included in this is  stx_mask  which
       indicates  what  other information has been returned.  stx_mask has the
       same format as the mask argument and bits are set  in  it  to  indicate
       which fields have been filled in.

       It  should  be  noted  that  the  kernel may return fields that weren't
       requested and may fail to return fields that were requested,  depending
       on what the backing filesystem supports.  (Fields that are given values
       despite being unrequested  can  just  be  ignored.)   In  either  case,
       stx_mask will not be equal mask.

       If  a  filesystem  does  not  support  a field or if it has an unrepre-
       sentable value (for instance, a file with an  exotic  type),  then  the
       mask  bit  corresponding to that field will be cleared in stx_mask even
       if the user asked for it and a dummy value will be filled in  for  com-
       patibility  purposes if one is available (e.g., a dummy UID and GID may
       be specified to mount under some circumstances).

       A filesystem may also fill in fields that the caller didn't ask for  if
       it has values for them available and the information is available at no
       extra cost.  If this happens, the corresponding bits  will  be  set  in

       Note:  for  performance and simplicity reasons, different fields in the
       statx structure may contain state information  from  different  moments
       during  the  execution of the system call.  For example, if stx_mode or
       stx_uid is changed by another process by calling chmod(2) or  chown(2),
       stat()  might return the old stx_mode together with the new stx_uid, or
       the old stx_uid together with the new stx_mode.

       Apart from stx_mask (which is described above), the fields in the statx
       structure are:

              The "preferred" block size for efficient filesystem I/O.  (Writ-
              ing to a file in smaller chunks may cause an  inefficient  read-

              Further  status  information  about the file (see below for more

              The number of hard links on a file.

              This field contains the user ID of the owner of the file.

              This field contains the ID of the group owner of the file.

              The file type and mode.  See inode(7) for details.

              The inode number of the file.

              The size of the file (if it is a  regular  file  or  a  symbolic
              link)  in  bytes.   The size of a symbolic link is the length of
              the pathname it contains, without a terminating null byte.

              The number of blocks allocated to the file  on  the  medium,  in
              512-byte units.  (This may be smaller than stx_size/512 when the
              file has holes.)

              A mask indicating which bits in stx_attributes are supported  by
              the VFS and the filesystem.

              The file's last access timestamp.

              The file's creation timestamp.

              The file's last status change timestamp.

              The file's last modification timestamp.

       stx_dev_major and stx_dev_minor
              The device on which this file (inode) resides.

       stx_rdev_major and stx_rdev_minor
              The  device  that this file (inode) represents if the file is of
              block or character device type.

       For further information on the above fields, see inode(7).

   File attributes
       The stx_attributes field contains a set of  ORed  flags  that  indicate
       additional attributes of the file.  Note that any attribute that is not
       indicated as supported by stx_attributes_mask has no usable value here.
       The    bits    in    stx_attributes_mask   correspond   bit-by-bit   to

       The flags are as follows:

              The file is compressed by the  filesystem  and  may  take  extra
              resources to access.

              The file cannot be modified: it cannot be deleted or renamed, no
              hard links can be created to this file and no data can be  writ-
              ten to it.  See chattr(1).

              The  file can only be opened in append mode for writing.  Random
              access writing is not permitted.  See chattr(1).

              File is not a candidate for backup when a backup program such as
              dump(8) is run.  See chattr(1).

              A  key  is required for the file to be encrypted by the filesys-

       On success, zero is returned.  On error, -1 is returned, and  errno  is
       set appropriately.

       EACCES Search  permission  is  denied for one of the directories in the
              path prefix of pathname.  (See also path_resolution(7).)

       EBADF  dirfd is not a valid open file descriptor.

       EFAULT pathname or statxbuf is NULL or points to a location outside the
              process's accessible address space.

       EINVAL Invalid flag specified in flags.

       EINVAL Reserved flag specified in mask.

       ELOOP  Too  many  symbolic links encountered while traversing the path-

              pathname is too long.

       ENOENT A component of pathname does not exist, or pathname is an  empty
              string and AT_EMPTY_PATH was not specified in flags.

       ENOMEM Out of memory (i.e., kernel memory).

              A component of the path prefix of pathname is not a directory or
              pathname is relative and dirfd is a file descriptor referring to
              a file other than a directory.

       statx() was added to Linux in kernel 4.11.

       statx() is Linux-specific.

       Glibc  does  not  (yet)  provide a wrapper for the statx() system call;
       call it using syscall(2).

       ls(1), stat(1), access(2), chmod(2),  chown(2),  readlink(2),  stat(2),
       utime(2), capabilities(7), inode(7), symlink(7)

       This  page  is  part of release 4.15 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at

Linux                             2017-09-15                          STATX(2)
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