chmod
Hurricane Electric Internet Services
NAME
chmod, fchmod - change permissions of a file
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
int chmod(const char *path, mode_t mode);
int fchmod(int fildes, mode_t mode);
DESCRIPTION
The mode of the file given by path or referenced by
filedes is changed.
Modes are specified by or'ing the following:
S_ISUID 04000 set user ID on execution
S_ISGID 02000 set group ID on execution
S_ISVTX 01000 sticky bit
S_IRUSR (S_IREAD)
00400 read by owner
S_IWUSR (S_IWRITE)
00200 write by owner
S_IXUSR (S_IEXEC)
00100 execute/search by owner
S_IRGRP 00040 read by group
S_IWGRP 00020 write by group
S_IXGRP 00010 execute/search by group
S_IROTH 00004 read by others
S_IWOTH 00002 write by others
S_IXOTH 00001 execute/search by others
The effective UID of the process must be zero or must
match the owner of the file.
The effective UID or GID must be appropriate for setting
execution bits.
Depending on the file system, set user ID and set group ID
execution bits may be turned off if a file is written. On
some file systems, only the super-user can set the sticky
bit, which may have a special meaning (i.e., for directo-
ries, a file can only be deleted by the owner or the
super-user).
RETURN VALUE
On success, zero is returned. On error, -1 is returned,
and errno is set appropriately.
ERRORS
Depending on the file system, other errors can be
returned. The more general errors for chmod are listed
below:
EPERM The effective UID does not match the owner of the
file, and is not zero.
EROFS The named file resides on a read-only file system.
EFAULT path points outside your accessible address space.
ENAMETOOLONG
path is too long.
ENOENT The file does not exist.
ENOMEM Insufficient kernel memory was available.
ENOTDIR A component of the path prefix is not a directory.
EACCES Search permission is denied on a component of the
path prefix.
ELOOP path contains a circular reference (i.e., via a
symbolic link)
The general errors for fchmod are listed below:
EBADF The descriptor is not value.
ENOENT See above.
EPERM See above.
EROFS See above.
SEE ALSO
open(2), chown(2), stat(2)
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.