selabel_lookup_best_match(3)Linux API documentationabel_lookup_best_match(3)

NAME         top

       selabel_lookup_best_match - obtain a best match SELinux security con‐
       text - Only supported on file backend.

SYNOPSIS         top

       #include <selinux/selinux.h>
       #include <selinux/label.h>

       int selabel_lookup_best_match(struct selabel_handle *hnd,
                                     char **context,
                                     const char *key,
                                     const char **links,
                                     int type);

       int selabel_lookup_best_match_raw(struct selabel_handle *hnd,
                                         char **context,
                                         const char *key,
                                         const char **links,
                                         int type);

DESCRIPTION         top

       selabel_lookup_best_match() performs a best match lookup operation on
       the handle hnd, returning the result in the memory pointed to by
       context, which must be freed by the caller using freecon(3).  The key
       parameter is a file path to check for best match using zero or more
       link (aliases) parameters. The order of precedence for best match is:

              1.  An exact match for the real path (key) or

              2.  An exact match for any of the links (aliases), or

              3.  The longest fixed prefix match.

       The type parameter is an optional file mode argument that should be
       set to the mode bits of the file, as determined by lstat(2).  mode
       may be zero, however full matching may not occur.

       selabel_lookup_best_match_raw() behaves identically to
       selabel_lookup_best_match() but does not perform context translation.

RETURN VALUE         top

       On success, zero is returned.  On error, -1 is returned and errno is
       set appropriately.

ERRORS         top

       ENOENT No context corresponding to the input key and type was found.

       EINVAL The key and/or type inputs are invalid, or the context being
              returned failed validation.

       ENOMEM An attempt to allocate memory failed.

NOTES         top

       Example usage - When a service creates a device node, it may also
       create one or more symlinks to the device node.  These symlinks may
       be the only stable name for the device, e.g. if the partition is
       dynamically assigned.  The file label backend supports this by
       looking up the "best match" for a device node based on its real path
       (key) and any links to it (aliases). The order of precedence for best
       match is described above.

SEE ALSO         top

       selabel_open(3), selabel_stats(3), selinux_set_callback(3),
       selinux(8), lstat(2), selabel_file(5)

COLOPHON         top

       This page is part of the selinux (Security-Enhanced Linux user-space
       libraries and tools) project.  Information about the project can be
       found at ⟨⟩.  If you
       have a bug report for this manual page, see 
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository 
       ⟨⟩ on 2017-03-13.  If you
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Security Enhanced Linux          05 May 2015    selabel_lookup_best_match(3)