trusty (2) fchmodat.2.gz

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NAME
       fchmodat - change permissions of a file relative to a directory file descriptor


SYNOPSIS
       #include <fcntl.h>           /* Definition of AT_* constants */
       #include <sys/stat.h>

       int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       fchmodat():
           Since glibc 2.10:
               _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _ATFILE_SOURCE


DESCRIPTION
       The  fchmodat()  system  call  operates  in  exactly the same way as chmod(2), except for the differences
       described in this manual page.

       If the pathname given in pathname is relative, then it is interpreted relative to the directory  referred
       to  by  the  file  descriptor dirfd (rather than relative to the current working directory of the calling
       process, as is done by chmod(2) for a relative pathname).

       If pathname is relative and dirfd is the special value AT_FDCWD, then pathname is interpreted relative to
       the current working directory of the calling process (like chmod(2)).

       If pathname is absolute, then dirfd is ignored.

       flags can either be 0, or include the following flag:

       AT_SYMLINK_NOFOLLOW
              If  pathname  is a symbolic link, do not dereference it: instead operate on the link itself.  This
              flag is not currently implemented.


RETURN VALUE
       On success, fchmodat() returns 0.  On error, -1 is returned and errno is set to indicate the error.


ERRORS
       The same errors that occur for chmod(2) can also occur for fchmodat().  The following  additional  errors
       can occur for fchmodat():

       EBADF  dirfd is not a valid file descriptor.

       EINVAL Invalid flag specified in flags.

       ENOTDIR
              pathname is relative and dirfd is a file descriptor referring to a file other than a directory.

       ENOTSUP
              flags specified AT_SYMLINK_NOFOLLOW, which is not supported.


VERSIONS
       fchmodat() was added to Linux in kernel 2.6.16; library support was added to glibc in version 2.4.


CONFORMING TO
       POSIX.1-2008.


NOTES
       See openat(2) for an explanation of the need for fchmodat().

       The GNU C library wrapper function implements the POSIX-specified interface described in this page.  This
       interface differs from the underlying Linux system call, which does not have a flags argument.


SEE ALSO
       chmod(2), openat(2), path_resolution(7), symlink(7)


COLOPHON
       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.