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CHFLAGS(2) System Calls Manual CHFLAGS(2)

chflags, chflagsat, fchflags — set file flags

#include <sys/stat.h>

int
chflags(const char *path, unsigned int flags);

int
fchflags(int fd, unsigned int flags);

#include <sys/stat.h>
#include <fcntl.h>

int
chflagsat(int fd, const char *path, unsigned int flags, int atflags);

The file whose name is given by path or referenced by the descriptor fd has its flags changed to flags.

The flags are the bitwise OR of zero or more of the following values:

Do not dump the file.
The file may not be changed.
The file may only be appended to.
The file may be archived.
The file may not be changed.
The file may only be appended to.

The UF_IMMUTABLE and UF_APPEND flags may be set or unset by either the owner of a file or the superuser.

The SF_ARCHIVED, SF_IMMUTABLE and SF_APPEND flags may only be set or unset by the superuser. They may be set at any time, but normally may only be unset when the system is in single-user mode. (See init(8) for details.)

The () function is equivalent to () except in the case where path specifies a relative path. In this case the file to be changed is determined relative to the directory associated with the file descriptor fd instead of the current working directory.

If () is passed the special value AT_FDCWD (defined in <fcntl.h>) in the fd parameter, the current working directory is used. If atflags is also zero, the behavior is identical to a call to ().

The atflags argument is the bitwise OR of zero or more of the following values:

If path names a symbolic link, then the flags of the symbolic link are changed.

The () function is equivalent to () except that the file whose flags are changed is specified by the file descriptor fd.

Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

chflags() will fail if:

[]
A component of the path prefix is not a directory.
[]
A component of a pathname exceeded NAME_MAX characters, or an entire pathname (including the terminating NUL) exceeded PATH_MAX bytes.
[]
The named file does not exist.
[]
Search permission is denied for a component of the path prefix.
[]
Too many symbolic links were encountered in translating the pathname.
[]
The effective user ID does not match the owner of the file and the effective user ID is not the superuser, or the effective user ID is not the superuser and at least one of the super-user-only flags for the named file would be changed.
[]
The named file resides on a file system that does not support file flags.
[]
The named file resides on a read-only file system.
[]
path points outside the process's allocated address space.
[]
An I/O error occurred while reading from or writing to the file system.
[]
The flags value is invalid.
[]
The descriptor references a block or character device and the effective user ID is not the superuser.

fchflags() will fail if:

[]
The descriptor is not valid.
[]
fd refers to a socket, not to a file.
[]
The descriptor references a block or character device and the effective user ID is not the superuser.
[]
The flags value is invalid.
[]
The effective user ID does not match the owner of the file and the effective user ID is not the superuser, or the effective user ID is not the superuser and at least one of the super-user-only flags for the named file would be changed.
[]
The named file resides on a file system that does not support file flags.
[]
The file resides on a read-only file system.
[]
An I/O error occurred while reading from or writing to the file system.

chflags(1), init(8)

The chflags() and fchflags() functions first appeared in 4.3BSD-Reno. The chflagsat() function first appeared in FreeBSD 10.0. It was added to OpenBSD in OpenBSD 5.7.

August 4, 2022 OpenBSD-7.6