NAME

File::Strmode - Converts a file mode into a symbolic string

SYNOPSIS

  use File::Strmode;

  my $mode = (stat $filename)[2];
  my $strmode = strmode($mode);
  print "$strmode $filename\n";

DESCRIPTION

The strmode() function exported from this module converts a file mode (the type and permission information associated with an inode, see "stat" in perlfunc) into a symbolic string. This string is eleven characters in length.

BSD derived operating systems offer this function as part of its C library. The following description has been copied from the NetBSD strmode man page:

The first character is the inode type, and will be one of the following:

  -     regular file
  a     regular file in archive state 1
  A     regular file in archive state 2
  b     block special
  c     character special
  d     directory
  l     symbolic link
  p     fifo
  s     socket
  w     whiteout
  ?     unknown inode type

The next nine characters encode three sets of permissions, in three characters each. The first three characters are the permissions for the owner of the file, the second three for the group the file belongs to, and the third for the other, or default, set of users.

Permission checking is done as specifically as possible. If read permission is denied to the owner of a file in the first set of permissions, the owner of the file will not be able to read the file. This is true even if the owner is in the file's group and the group permissions allow reading or the other permissions allow reading.

If the first character of the three character set is an r, the file is readable for that set of users; if a dash -, it is not readable.

If the second character of the three character set is a w, the file is writable for that set of users; if a dash -, it is not writable.

The third character is the first of the following characters that apply:

S

If the character is part of the owner permissions and the file is not executable or the directory is not searchable by the owner, and the set-user-id bit is set.

S

If the character is part of the group permissions and the file is not executable or the directory is not searchable by the group, and the set-group-id bit is set.

T

If the character is part of the other permissions and the file is not executable or the directory is not searchable by others, and the sticky (S_ISVTX) bit is set.

s

If the character is part of the owner permissions and the file is executable or the directory searchable by the owner, and the set- user-id bit is set.

s

If the character is part of the group permissions and the file is executable or the directory searchable by the group, and the set- group-id bit is set.

t

If the character is part of the other permissions and the file is executable or the directory searchable by others, and the sticky (S_ISVTX) bit is set.

x

The file is executable or the directory is searchable.

-

None of the above apply.

The last character is a plus sign + if there are any alternative or additional access control methods associated with the inode, otherwise it will be a space.

Archive state 1 and archive state 2 represent file system dependent ar- chive state for a file. Most file systems do not retain file archive state, and so will not report files in either archive state. msdosfs will report a file in archive state 1 if it has been archived more recently than modified. Hierarchical storage systems may have multiple archive states for a file and may define archive states 1 and 2 as appro- priate.

SEE ALSO

strmode(2), "stat" in perlfunc, "lstat" in perlfunc.

COPYRIGHT AND LICENSE

Copyright (C) 2009 by Salvador Fandiño (sfandino@yahoo.com)

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.10.0 or, at your option, any later version of Perl 5 you may have available.

This manual page is based on NetBSD strmode manual page that has the following copyright:

Copyright (c) 1994-2009 The NetBSD Foundation, Inc.