plan9 man page for stat

STAT(5) 							File Formats Manual							   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 <libc.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 fcall(2))  con-
       vert between directory entries and C structs.

       This encoding may be turned into a machine dependent Dir structure (see stat(2)) using routines defined in fcall(2).

       The  mode  contains  permission	bits as described in intro(5) and the following: 0x80000000 (this file is a directory), 0x40000000 (append
       only), 0x20000000 (exclusive use).  Writes to append-only files always place their data at the end of the file; the offset in the  read	or
       write  message  is  ignored, as is the OTRUNC bit in an open.  Exclusive use files may be open for I/O by only one fid at a time across all
       clients of the server.  If a second open is attempted, it draws an error.  Servers may implement a timeout on the lock on an exclusive  use
       file:  if  the  fid holding the file open has been unused for an extended period (of order at least minutes), it is reasonable to break the
       lock and deny the initial fid further I/O.

       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.	Similarly, the atime field records the last read of the  contents;
       also  it  is  set  whenever mtime is set.  In addition, for a directory, it is set by an attach, walk, or create, all whether successful or
       not.

       The length records the number of bytes in the file.  Directories and most files representing devices have a conventional length of 0.

       The stat request requires no special permissions.

       The wstat request can change some of the file status information.  The name can be changed by anyone with write permission  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 and users(6) for users and groups).  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 fstat and stat.

       Wstat messages are generated by fwstat and wstat.

																	   STAT(5)