getxattr(2) System Calls Manual getxattr(2)
NAME
getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <sys/xattr.h>
ssize_t getxattr(const char *path, const char *name,
void value[.size], size_t size);
ssize_t lgetxattr(const char *path, const char *name,
void value[.size], size_t size);
ssize_t fgetxattr(int fd, const char *name,
void value[.size], size_t size);
DESCRIPTION
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 attri-
bute 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 sym-
bolic 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 in-
cludes a namespace prefix; there may be several, disjoint namespaces
associated with an individual inode. The value of an extended attri-
bute 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.)
RETURN VALUE
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 to indicate the error.
ERRORS
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.
ENODATA
The named attribute does not exist, or the process has no access
to this attribute.
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.
VERSIONS
These system calls have been available since Linux 2.4; glibc support
is provided since glibc 2.3.
STANDARDS
These system calls are Linux-specific.
EXAMPLES
See listxattr(2).
SEE ALSO
getfattr(1), setfattr(1), listxattr(2), open(2), removexattr(2), setx-
attr(2), stat(2), symlink(7), xattr(7)
Linux man-pages 6.03 2022-12-04 getxattr(2)
Generated by dwww version 1.15 on Thu Jun 27 09:26:19 CEST 2024.