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The function
converts a file (the type and permission information associated with an
inode, see into a symbolic string which is stored in the location referenced
by This stored string is eleven characters in length plus a trailing
The first character is the inode type, and will be one of the following:
regular file block special character special directory symbolic
link fifo socket 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: 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. 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. 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’’ bit is set. 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. 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. If the character is part of
the other permissions and the file is executable or the directory searchable,
by others, and the ‘‘sticky’’ bit is set. The file is executable or the directory
is searchable. None of the above apply. The last character is a plus sign
‘‘+’’ if any there are any alternate or additional access control methods associated
with the inode, otherwise it will be a space.
The function
always returns 0.
The function
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