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LISTXATTR   (2) manpage
LISTXATTR
2
Extended Attributes
Dec 2001
System calls
  • NAME
      listxattr, llistxattr, flistxattr - list extended attribute names
  • SYNOPSIS 
      
 #include <sys/types.h>
 #include <attr/xattr.h>

 ssize_t listxattr (const char\ * path ,
  \t\t\t\t char\ * list , size_t  size );   ssize_t llistxattr (const char\ * path ,   \t\t\t\t char\ * list , size_t  size );   ssize_t flistxattr (int  filedes ,   \t\t\t\t char\ * list , size_t  size );
  • DESCRIPTION
      Extended attributes are name:value
      pairs associated with inodes (files, directories, symlinks, 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
      attr(5) .


      listxattr retrieves the
      list
       of extended attribute names associated with the given
      path
       in the filesystem.
      The list is the set of (NULL-terminated) names, one after the other.
      Names of extended attributes to which the calling process does not
      have access may be omitted from the list.
      The length of the attribute name
      list
       is returned.
      llistxattr is identical to
      listxattr ,
       except in the case of a symbolic link, where the list of names of
      extended attributes associated with the link itself is retrieved,
      not the file that it refers to.
      flistxattr is identical to
      listxattr ,
       only the open file pointed to by
      filedes
       (as returned by
      open(2) )
       is interrogated in place of
      path .


      A single extended attribute
      name
       is a simple NULL-terminated string.
      The name includes a namespace prefix - there may be several, disjoint
      namespaces associated with an individual inode.
      An empty buffer of
      size
       zero can be passed into these calls to return the current size of the
      list of extended attribute names, which can be used to estimate the
      size of a buffer which is sufficiently large to hold the list of names.
  • EXAMPLES
      The
      list
       of names is returned as an unordered array of NULL-terminated character
      strings (attribute names are separated by NULL characters), like this:
      
user.name1\0system.name1\0user.name2\0
      Filesystems like ext2, ext3 and XFS which implement POSIX ACLs using extended attributes, might return a list like this: 
      
system.posix_acl_access\0system.posix_acl_default\0
  • RETURN VALUE
      On success, a positive number is returned indicating the size of the extended attribute name list. On failure, -1 is returned and errno is set appropriately.

      If the size of the list buffer is too small to hold the result, errno is set to ERANGE.

      If extended attributes are not supported by the filesystem, or are disabled, errno is set to ENOTSUP.

      The errors documented for the stat(2) system call are also applicable here.
  • AUTHORS
      Andreas Gruenbacher, < a.gruenbacher@computer.org > and the SGI XFS development team, < linux-xfs@oss.sgi.com >. Please send any bug reports or comments to these addresses.
  • SEE ALSO
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