getxattr

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

NAME
       getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value

SYNOPSIS
       #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);

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 appropriately.

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 on Linux since kernel 2.4; glibc
       support is provided since version 2.3.

CONFORMING TO
       These system calls are Linux-specific.

EXAMPLE
       See listxattr(2).

SEE ALSO
       getfattr(1),  setfattr(1), listxattr(2), open(2), removexattr(2), setx-
       attr(2), stat(2), symlink(7), xattr(7)

COLOPHON
       This page is part of release 5.05 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                             2019-03-06                       GETXATTR(2)