fchmodat(2)

1FCHMODAT(2)                Linux Programmer's Manual               FCHMODAT(2)
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NAME

6       fchmodat  -  change  permissions of a file relative to a directory file
7       descriptor
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SYNOPSIS

10       #define _ATFILE_SOURCE
11       #include <sys/stat.h>
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13       int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags);
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DESCRIPTION

16       The fchmodat()  system  call  operates  in  exactly  the  same  way  as
17       chmod(2), except for the differences described in this manual page.
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19       If  the  pathname given in pathname is relative, then it is interpreted
20       relative to the directory referred to  by  the  file  descriptor  dirfd
21       (rather  than  relative to the current working directory of the calling
22       process, as is done by chmod(2) for a relative pathname).
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24       If pathname is relative and dirfd is the special value  AT_FDCWD,  then
25       pathname  is  interpreted  relative to the current working directory of
26       the calling process (like chmod(2)).
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28       If pathname is absolute, then dirfd is ignored.
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30       flags can either be 0, or include the following flag:
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32       AT_SYMLINK_NOFOLLOW
33              If pathname is a symbolic link, do not dereference  it:  instead
34              operate  on  the link itself.  This flag is not currently imple‐
35              mented.
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RETURN VALUE

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

42       The  same errors that occur for chmod(2) can also occur for fchmodat().
43       The following additional errors can occur for fchmodat():
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45       EBADF  dirfd is not a valid file descriptor.
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47       EINVAL Invalid flag specified in flags.
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49       ENOTDIR
50              pathname is relative and dirfd is a file descriptor referring to
51              a file other than a directory.
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53       ENOTSUP
54              flags specified AT_SYMLINK_NOFOLLOW, which is not supported.
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NOTES

57       See openat(2) for an explanation of the need for fchmodat().
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CONFORMING TO

60       This  system  call  is  non-standard but is proposed for inclusion in a
61       future revision of POSIX.1.
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VERSIONS

64       fchmodat() was added to Linux in kernel 2.6.16.
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