PR11015 Support shared library reloading (in different processes)

* runtime/task_finder_vma.c (stap_remove_vma_map_info): Return negative
  status on failure.
  (stap_find_vma_map_info): Likewise.
  (stap_find_vma_map_info_user): New function.
  (stap_drop_vma_maps): New function.
* runtime/sym.h (addr): Renamed to static_addr, to store addresses for
  sections which are always mapped at the same address.
  (_stp_module_relocate): Add extra struct task_struct *tsk argument.
* runtime/sym.c (_stp_tf_exec_cb): New callback, calls stap_drop_vma_maps.
  (_stp_tf_mmap_cb): Don't store address in module.section, but call
  stap_add_vma_map_info() per tsk->group_leader for matched module.
  Don't register empty/null modules.
  (_stp_module_relocate): Take extra struct task_struct *tsk argument,
  cache last tsk used. Only use section->static_addr for none dynamic
  modules. Use stap_find_vma_map_info_user() to locate dynamic modules.
  (_stp_mod_sec_lookup): Add extra argument unsigned long *rel_addr to
  optionally store relative address when module/section found.
  (_stp_kallsyms_lookup): Use _stp_mod_sec_lookup to find relative address.
  (_stp_sym_init): Register _stp_tf_exec_cb in stap_task_finder_target.
  Add error check to see if task finder could be initialized.
* dwflpp.cxx (emit_address): Pass NULL for kernel/modules and current for
  user tasks to _stp_module_relocate.
* runtime/transport/symbols.c (_stp_do_relocation): Set new static_addr
  _stp_section field.
* runtime/unwind.c (adjustStartLoc): Take new struct task_struct *tsk
  argument and pass to stap_find_vma_map_info_user and _stp_module_relocate
  to find adjusted addr.
  (_stp_search_unwind_hdr): Pass through struct task_struct *tsk.
  (unwind_frame): Likewise.
* tapset/context-symbols.stp (probemod): Add NULL to _stp_mod_sec_lookup
  call to indicate we aren't interested in relative address.
* tapsets.cxx (dwarf_derived_probe_group::emit_module_init): Pass NULL to
  _stp_module_relocate to indicate kernel/module address.

1 files changed, 5 insertions, 2 deletions

diff --git a/runtime/sym.h b/runtime/sym.h
index 9f2bdfd0..ce6ab736 100644
--- a/runtime/sym.h
+++ b/runtime/sym.h
@@ -17,7 +17,7 @@ struct _stp_symbol {
 
 struct _stp_section {
         const char *name;
-        unsigned long addr; /* XXX: belongs in per-address-space tables */
+        unsigned long static_addr; /* XXX non-null if everywhere the same. */
 	unsigned long size; /* length of the address space module covers. */
 	struct _stp_symbol *symbols;  /* ordered by address */
   	unsigned num_symbols;
@@ -70,7 +70,10 @@ static unsigned long _stp_kretprobe_trampoline;
    _stp_sym_init () should track vma maps. */
 static char _stp_need_vma_tracker;
 
-static unsigned long _stp_module_relocate (const char *module, const char *section, unsigned long offset);
+static unsigned long _stp_module_relocate (const char *module,
+					   const char *section,
+					   unsigned long offset,
+					   struct task_struct *tsk);
 static struct _stp_module *_stp_get_unwind_info (unsigned long addr);
 
 #endif /* _STP_SYM_H_ */