Make jdk-1.1.8 work again. It turns out that some code inside

libjava peeks into the dynamic linker's private Obj_Entry structures.
My recent changes introduced some new members near the front of
the structures, causing libjava to get the wrong fields.  This commit
moves the new members toward the end of the structure so that the
layout of the portion that is relevant to JDK remains the same as
before.

I will work with the JDK porting team to see if we can come up with
a less fragile way for them to do what they need to do.  I understand
the current approach was necessary in order to work around some
limitations of the dynamic linker.  Maybe it's not necessary any
more.

1 files changed, 9 insertions, 5 deletions

diff --git a/libexec/rtld-elf/rtld.h b/libexec/rtld-elf/rtld.h
index 0cdbe4c..c63e7d0 100644
--- a/libexec/rtld-elf/rtld.h
+++ b/libexec/rtld-elf/rtld.h
@@ -70,6 +70,10 @@ typedef struct Struct_Needed_Entry {
  *
  * Items marked with "(%)" are dynamically allocated, and must be freed
  * when the structure is destroyed.
+ *
+ * CAUTION: It appears that the JDK port peeks into these structures.
+ * It looks at "next" and "mapbase" at least.  Don't add new members
+ * near the front, until this can be straightened out.
  */
 typedef struct Struct_Obj_Entry {
     /*
@@ -80,12 +84,7 @@ typedef struct Struct_Obj_Entry {
     Elf_Word version;		/* Version number of struct format */
 
     struct Struct_Obj_Entry *next;
-    Objlist dldags;		/* Object belongs to these dlopened DAGs (%) */
-    Objlist dagmembers;		/* DAG has these members (%) */
     char *path;			/* Pathname of underlying file (%) */
-    dev_t dev;			/* Object's filesystem's device */
-    ino_t ino;			/* Object's inode number */
-    unsigned long mark;		/* Set to "curmark" to avoid repeat visits */
     int refcount;
     int dl_refcount;		/* Number of times loaded by dlopen */
 
@@ -133,6 +132,11 @@ typedef struct Struct_Obj_Entry {
     bool traced;		/* Already printed in ldd trace output */
 
     struct link_map linkmap;	/* for GDB */
+    Objlist dldags;		/* Object belongs to these dlopened DAGs (%) */
+    Objlist dagmembers;		/* DAG has these members (%) */
+    dev_t dev;			/* Object's filesystem's device */
+    ino_t ino;			/* Object's inode number */
+    unsigned long mark;		/* Set to "curmark" to avoid repeat visits */
 } Obj_Entry;
 
 #define RTLD_MAGIC	0xd550b87a