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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | EXAMPLE | SEE ALSO | COLOPHON |
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GETXATTR(2) Linux Programmer's Manual GETXATTR(2)
getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value
#include <sys/types.h>
#include <sys/xattr.h>
ssize_t getxattr(const char *path, const char *name,
void *value, size_t size);
ssize_t lgetxattr(const char *path, const char *name,
void *value, size_t size);
ssize_t fgetxattr(int fd, const char *name,
void *value, size_t size);
Extended attributes are name:value pairs associated with inodes
(files, directories, symbolic links, etc.). They are extensions to
the normal attributes which are associated with all inodes in the
system (i.e., the stat(2) data). A complete overview of extended
attributes concepts can be found in xattr(7).
getxattr() retrieves the value of the extended attribute identified
by name and associated with the given path in the filesystem. The
attribute value is placed in the buffer pointed to by value; size
specifies the size of that buffer. The return value of the call is
the number of bytes placed in value.
lgetxattr() is identical to getxattr(), except in the case of a
symbolic link, where the link itself is interrogated, not the file
that it refers to.
fgetxattr() is identical to getxattr(), only the open file referred
to by fd (as returned by open(2)) is interrogated in place of path.
An extended attribute name is a null-terminated string. The name
includes a namespace prefix; there may be several, disjoint
namespaces associated with an individual inode. The value of an
extended attribute is a chunk of arbitrary textual or binary data
that was assigned using setxattr(2).
If size is specified as zero, these calls return the current size of
the named extended attribute (and leave value unchanged). This can
be used to determine the size of the buffer that should be supplied
in a subsequent call. (But, bear in mind that there is a possibility
that the attribute value may change between the two calls, so that it
is still necessary to check the return status from the second call.)
On success, these calls return a nonnegative value which is the size
(in bytes) of the extended attribute value. On failure, -1 is
returned and errno is set appropriately.
E2BIG The size of the attribute value is larger than the maximum
size allowed; the attribute cannot be retrieved. This can
happen on filesystems that support very large attribute values
such as NFSv4, for example.
ENOATTR
The named attribute does not exist, or the process has no
access to this attribute. (ENOATTR is defined to be a synonym
for ENODATA in <attr/xattr.h>.)
ENOTSUP
Extended attributes are not supported by the filesystem, or
are disabled.
ERANGE The size of the value buffer is too small to hold the result.
In addition, the errors documented in stat(2) can also occur.
These system calls have been available on Linux since kernel 2.4;
glibc support is provided since version 2.3.
These system calls are Linux-specific.
See listxattr(2).
getfattr(1), setfattr(1), listxattr(2), open(2), removexattr(2),
setxattr(2), stat(2), symlink(7), xattr(7)
This page is part of release 4.15 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2017-03-13 GETXATTR(2)
Pages that refer to this page: listxattr(2), open(2), removexattr(2), setxattr(2), syscalls(2), symlink(7), xattr(7)
Copyright and license for this manual page
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