With this commit, I hereby pronounce gensetdefs past its use-by date.

Replace the a.out emulation of 'struct linker_set' with something
a little more flexible.  <sys/linker_set.h> now provides macros for
accessing elements and completely hides the implementation.

The linker_set.h macros have been on the back burner in various
forms since 1998 and has ideas and code from Mike Smith (SET_FOREACH()),
John Polstra (ELF clue) and myself (cleaned up API and the conversion
of the rest of the kernel to use it).

The macros declare a strongly typed set.  They return elements with the
type that you declare the set with, rather than a generic void *.

For ELF, we use the magic ld symbols (__start_<setname> and
__stop_<setname>).  Thanks to Richard Henderson <rth@redhat.com> for the
trick about how to force ld to provide them for kld's.

For a.out, we use the old linker_set struct.

NOTE: the item lists are no longer null terminated.  This is why
the code impact is high in certain areas.

The runtime linker has a new method to find the linker set
boundaries depending on which backend format is in use.

linker sets are still module/kld unfriendly and should never be used
for anything that may be modular one day.

Reviewed by:	eivind

1 files changed, 14 insertions, 0 deletions

diff --git a/sys/kern/linker_if.m b/sys/kern/linker_if.m
index 5f6f239..be84b9e 100644
--- a/sys/kern/linker_if.m
+++ b/sys/kern/linker_if.m
@@ -54,6 +54,20 @@ METHOD int search_symbol {
 };
 
 #
+# Search for a linker set in a file.  Return a pointer to the first
+# entry (which is itself a pointer), and the number of entries.
+# "stop" points to the entry beyond the last valid entry.
+# If count, start or stop are NULL, they are not returned.
+#
+METHOD int lookup_set {
+    linker_file_t	file;
+    const char*		name;
+    void***		start;
+    void***		stop;
+    int*		count;
+};
+
+#
 # Unload a file, releasing dependancies and freeing storage.
 #
 METHOD void unload {