CHFLAGS(2) System Calls Manual CHFLAGS(2)

chflags, lchflags, fchflags — set file flags

Standard C Library (libc, -lc)

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

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

int
lchflags(const char *path, u_long flags);

int
fchflags(int fd, u_long flags);

The file whose name is given by path or referenced by the descriptor fd has its flags changed to flags. For (), symbolic links are not traversed and thus their modes may be changed with this call.

The flags specified are formed by 'ing the following values:

Do not dump the file.
The file may not be changed.
The file may only be appended to.
The file (if a directory) is opaque for union mounts.
The file is archived.
The file may not be changed.
The file may only be appended to.

The UF_NODUMP, UF_IMMUTABLE, UF_APPEND, and UF_OPAQUE flags may be set or unset by either the owner of a file or the super-user, except on block and character devices, where only the super-user may set or unset them.

The SF_ARCHIVED, SF_IMMUTABLE, and SF_APPEND flags may only be set or unset by the super-user. These flags 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.)

Upon successful completion, a value of 0 is returned. Otherwise, -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 path name exceeded {PATH_MAX} characters.
[]
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 super-user, or the effective user ID is not the super-user and one or more 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.

fchflags() will fail if:

[]
The descriptor is not valid.
[]
fd refers to a socket, not to a file.
[]
The effective user ID does not match the owner of the file and the effective user ID is not the super-user, or the effective user ID is not the super-user and one or more of the super-user-only flags for the file would be changed.
[]
The 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), stat(2), stat_flags(3), init(8), mount_union(8)

The chflags() and fchflags() functions first appeared in 4.4BSD. The lchflags() function first appeared in NetBSD 1.5.

August 6, 2011 NetBSD 11.0