NAME
strmode —
convert inode status
information into a symbolic string
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
void
strmode(
mode_t
mode,
char *bp);
DESCRIPTION
The
strmode() function converts a file
mode (the type and permission information associated
with an inode, see
stat(2)) into a
symbolic string which is stored in the location referenced by
bp. This stored string is eleven characters in length
plus a trailing nul byte.
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 archive
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 appropriate.
SEE ALSO
chmod(1),
find(1),
stat(2),
getmode(3),
setmode(3)
HISTORY
The
strmode() function first appeared in
4.4BSD.