getxattr(2) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | EXAMPLES | SEE ALSO | COLOPHON

GETXATTR(2)             Linux Programmer's Manual            GETXATTR(2)

NAME         top

       getxattr, lgetxattr, fgetxattr - retrieve an extended attribute
       value

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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.)

RETURN VALUE         top

       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         top

       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         top

       These system calls have been available on Linux since kernel 2.4;
       glibc support is provided since version 2.3.

CONFORMING TO         top

       These system calls are Linux-specific.

EXAMPLES         top

       See listxattr(2).

SEE ALSO         top

       getfattr(1), setfattr(1), listxattr(2), open(2), removexattr(2),
       setxattr(2), stat(2), symlink(7), xattr(7)

COLOPHON         top

       This page is part of release 5.12 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                          2021-03-22                    GETXATTR(2)

Pages that refer to this page: listxattr(2)open(2)removexattr(2)setxattr(2)syscalls(2)capabilities(7)symlink(7)xattr(7)