STAT(5)                                                   STAT(5)

     NAME
          stat, wstat - inquire or change file attributes

     SYNOPSIS
          Tstat   tag[2] fid[2]
          Rstat   tag[2] fid[2] stat[116]

          Twstat  tag[2] fid[2] stat[116]
          Rwstat  tag[2] fid[2]

     DESCRIPTION
          The stat transaction inquires about the file identified by
          fid. The reply will contain a 116-byte (DIRLEN in <lib9.h>)
          machine-independent directory entry laid out as follows:

          name[28]         file name; must be / if the file is the
                           root directory of the server
          uid[28]          owner name
          gid[28]          group name
          qid.path[4]      the file server's identification for the
                           file
          qid.vers[4]      version number for given path
          mode[4]          permissions and flags
          atime[4]         last access time
          mtime[4]         last modification time
          length[8]        length of file in bytes
          type[2]          for kernel use
          dev[2]           for kernel use

          Integers in this encoding are in little-endian order (least
          significant byte first).  The convM2D and convD2M routines
          (see styx(10.2)) convert between directory entries and C
          structs.

          This encoding may be turned into a machine dependent Dir
          structure (see <lib9.h>) using routines defined in
          styx(10.2).

          The mode contains permission bits as described in intro(5)
          and 16r80000000 if this file is a directory.

          The two time fields are measured in seconds since the epoch
          (Jan 1 00:00 1970 GMT).  The mtime field reflects the time
          of the last change of content.  For a plain file, mtime is
          the time of the most recent create, open with truncation, or
          write; for a directory it is the time of the most recent
          remove, create, or wstat of a file in the directory.  Simi-
          larly, the atime field records the last read of the con-
          tents; also it is set whenever mtime is set.  In addition,
          for a directory, it is set by an attach, walk, or create,

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     STAT(5)                                                   STAT(5)

          all whether successful or not.

          The length records the number of bytes in the file.  Direc-
          tories and most files representing devices have a conven-
          tional length of 0.

          The stat request requires no special permissions.

          The wstat request can change some of the file status infor-
          mation.  The name can be changed by anyone with write per-
          mission in the parent directory; it is an error to change
          the name to that of an existing file.  The mode and mtime
          can be changed by the owner of the file or the group leader
          of the file's current group.  The directory bit cannot be
          changed by a wstat; the other defined permission and mode
          bits can.  The gid can be changed: by the owner if also a
          member of the new group; or by the group leader of the
          file's current group if also leader of the new group (see
          intro(5) for more information about permissions).  None of
          the other data can be altered by a wstat.  In particular,
          there is no way to change the owner of a file.

          A read of a directory yields an integral number of directory
          entries in the machine independent encoding given above (see
          read(5)).

     ENTRY POINTS
          Stat messages are generated by the fstat and stat calls (see
          sys-stat(2)).

          Wstat messages are generated by the fwstat and wstat calls
          (see sys-stat(2)).

     SEE ALSO
          sys-stat(2), intro(5), read(5), intro(10), styx(10.2)

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