getmode(3) [netbsd man page]

SETMODE(3)						   BSD Library Functions Manual 						SETMODE(3)

NAME

     getmode, setmode -- modify mode bits

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     void *
     setmode(const char *mode_str);

     mode_t
     getmode(const void *set, mode_t mode);

DESCRIPTION

     The setmode() function accepts a string representation of a file mode change, compiles it to binary form, and returns an abstract representa-
     tion that may be passed to getmode().  The string may be an numeric (octal) or symbolic string of the form accepted by chmod(1), and may rep-
     resent either an exact mode to set or a change to make to the existing mode.

     The getmode() function adjusts the file permission bits given by mode according to the compiled change representation set, and returns the
     adjusted mode.  While only the permission bits are altered, other parts of the file mode, particularly the type, may be examined.

     Because some of the possible symbolic values are defined relative to the file creation mask, setmode() may call umask(2), temporarily chang-
     ing the mask.  If this occurs, the file creation mask will be restored before setmode() returns.  If the calling program changes the value of
     its file creation mask after calling setmode(), setmode() must be called again to recompile the mode string if getmode() is to modify future
     file modes correctly.

     If the mode passed to setmode() is invalid, setmode() returns NULL.

EXAMPLES

     The effects of the shell command 'chmod a+x myscript.sh' can be duplicated as follows:

	   const char *file = "myscript.sh";
	   struct stat st;
	   mode_t newmode;

	   stat(file, &st);
	   newmode = getmode(setmode("a+x"), st.st_mode);
	   chmod(file, newmode);

ERRORS

     The setmode() function may fail and set errno for any of the errors specified for the library routines malloc(3) or strtol(3).  In addition,
     setmode() will fail and set errno to:

     [EINVAL]		The mode argument does not represent a valid mode.

SEE ALSO

     chmod(1), stat(2), umask(2), malloc(3)

HISTORY

     The getmode() and setmode() functions first appeared in 4.4BSD.

BUGS

     Each call to setmode allocates a small amount of memory that there is no correct way to free.

     The type of set should really be some opaque struct type used only by these functions rather than void *.

BSD
								  January 4, 2009							       BSD

STRMODE(3)                                                 BSD Library Functions Manual                                                 STRMODE(3)

NAME

     strmode -- convert inode status information into a symbolic string

LIBRARY

     Utility functions from BSD systems (libbsd, -lbsd)

SYNOPSIS

     #include <bsd/string.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.

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

           -     regular file
           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 permis-
     sions, 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 permis-
     sions 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 read-
     able.

     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 any there are any alternate or additional access control methods associated with the inode, other-
     wise it will be a space.

SEE ALSO

     chmod(1), find(1), stat(2), getmode(3), setmode(3)

HISTORY

     The strmode() function first appeared in 4.4BSD.

BSD                                                                July 28, 1994                                                               BSD