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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | SEE ALSO | AUTHOR | COLOPHON |
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ACL_GET_FILE(3) Library Functions Manual ACL_GET_FILE(3)
acl_get_file, acl_get_file_at — get an ACL by filename
Linux Access Control Lists library (libacl, -lacl).
<sys/types.h> <sys/acl.h> acl_t acl_get_file(const char *path_p,
acl_type_t type) acl_t acl_get_file_at(int dirfd,
const char *path_p, int at_flags, acl_type_t type)
The acl_get_file() function retrieves the access ACL associated
with a file or directory, or the default ACL associated with a
directory. The pathname for the file or directory is given in the
argument path_p. If path_p is a symbolic link, acl_get_file()
returns information about the file or directory the link refers
to.
The ACL is placed into working storage and acl_get_file() returns
a pointer to that storage.
In order to read an ACL from an object, a process must have read
access to the object's attributes.
The value of the argument type is used to indicate whether the
access ACL or the default ACL associated with path_p is returned.
If type is ACL_TYPE_ACCESS, the access ACL of path_p is returned.
If type is ACL_TYPE_DEFAULT, the default ACL of path_p is
returned. If type is ACL_TYPE_DEFAULT and no default ACL is
associated with the directory path_p, then an ACL containing zero
ACL entries is returned. If type specifies a type of ACL that
cannot be associated with path_p, then the function fails.
This function may cause memory to be allocated. The caller should
free any releasable memory, when the new ACL is no longer
required, by calling acl_free(3) with the (void*)acl_t returned by
acl_get_file() as an argument.
acl_get_file_at()
The acl_get_file_at() function operates in exactly the same way as
acl_get_file(), except for the differences described here.
If the pathname given in path_p 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 acl_get_file()).
If path_p is relative and dirfd is the special value AT_FDCWD,
then path_p is interpreted relative to the current working
directory of the calling process (like acl_get_file()).
If path_p is absolute, then dirfd is ignored.
The at_flags argument can either be 0, or include one or more of
the following flags ORed:
AT_EMPTY_PATH
If path_p is an empty string, operate on the file referred
to by dirfd (which may have been obtained using the
open(2) O_PATH flag). In this case, dirfd can refer to any
type of file, not just a directory, and the behavior of
acl_get_file_at() is similar to that of acl_get_fd().
AT_SYMLINK_NOFOLLOW
If path_p refers to a symbolic link, do not dereference
it: instead, fail the operation and set the global
variable errno to ENOTSUP. This indicates that the
symbolic link cannot have ACLs.
On success, the acl_get_file() and acl_get_file_at() functions
return a pointer to the working storage. On error, a value of
(acl_t)NULL is returned, and errno is set appropriately.
If any of the following conditions occur, the acl_get_file() and
acl_get_file_at() functions return a value of (acl_t)NULL and set
errno to the corresponding value:
[EACCES] Search permission is denied for a component of
the path prefix or the object exists and the
process does not have appropriate access
rights.
Argument type specifies a type of ACL that
cannot be associated with path_p.
[EBADF] The argument path_p is relative but the
argument dirfd is neither AT_FDCWD nor a valid
file descriptor.
[EINVAL] The argument type is not ACL_TYPE_ACCESS or
ACL_TYPE_DEFAULT.
An invalid flag was specified in the at_flags
argument.
[ENAMETOOLONG] The length of the argument path_p is too long.
[ENOENT] The named object does not exist or the argument
path_p points to an empty string.
[ENOMEM] The ACL working storage requires more memory
than is allowed by the hardware or system-
imposed memory management constraints.
[ENOTDIR] A component of the path prefix is not a
directory.
The argument path_p is relative and the
argument dirfd is a file descriptor referring
to a file other than a directory.
[ENOTSUP] The argument at_flags includes the flag
AT_SYMLINK_NOFOLLOW and path_p is a symbolic
link.
The file system on which the file identified by
path_p is located does not support ACLs, or
ACLs are disabled.
IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned)
Function acl_get_file_at() is a Linux specific extension.
acl_free(3), acl_get_entry(3), acl_get_fd(3), acl_set_file(3),
acl(5)
Derived from the FreeBSD manual pages written by Robert N M Watson
<rwatson@FreeBSD.org>, and adapted for Linux by Andreas
Gruenbacher <andreas.gruenbacher@gmail.com>.
This page is part of the acl (manipulating access control lists)
project. Information about the project can be found at
http://savannah.nongnu.org/projects/acl. If you have a bug report
for this manual page, see
⟨http://savannah.nongnu.org/bugs/?group=acl⟩. This page was
obtained from the project's upstream Git repository
⟨git://git.savannah.nongnu.org/acl.git⟩ on 2026-08-03. (At that
time, the date of the most recent commit that was found in the
repository was 2026-06-29.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Linux ACL June 5, 2026 ACL_GET_FILE(3)
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HTML rendering created 2026-09-09 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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