From: Gabriel Corona <gabriel.corona@loria.fr>
Date: Mon, 14 Mar 2016 10:38:16 +0000 (+0100)
Subject: [mc] Move process_vm_readv-based implementation of libunwind in simgrid::mc
X-Git-Tag: v3_13~428^2
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/a0abc19be8f29dbf8bd64487b4a3dee7f8501b48

[mc] Move process_vm_readv-based implementation of libunwind in simgrid::mc
---

diff --git a/src/mc/Process.cpp b/src/mc/Process.cpp
index 1c003948d2..613eec4f8b 100644
--- a/src/mc/Process.cpp
+++ b/src/mc/Process.cpp
@@ -227,8 +227,9 @@ void Process::init()
   this->smx_process_infos.clear();
   this->smx_old_process_infos.clear();
   this->unw_addr_space = unw_create_addr_space(&mc_unw_accessors  , __BYTE_ORDER);
-  this->unw_underlying_addr_space = unw_create_addr_space(&mc_unw_vmread_accessors, __BYTE_ORDER);
-  this->unw_underlying_context = _UPT_create(this->pid_);
+  this->unw_underlying_addr_space = simgrid::unw::create_addr_space();
+  this->unw_underlying_context = simgrid::unw::create_context(
+    this->unw_underlying_addr_space, this->pid_);
 }
 
 Process::~Process()
diff --git a/src/mc/mc_unw.h b/src/mc/mc_unw.h
index 3470bd8580..d27fbd1ce9 100644
--- a/src/mc/mc_unw.h
+++ b/src/mc/mc_unw.h
@@ -26,29 +26,27 @@
  *  much here.
  */
 
+#include <sys/types.h>
+
 #include <xbt/base.h>
 
 #include <libunwind.h>
 
-#include "src/mc/Process.hpp"
+#include "src/mc/mc_forward.hpp"
+
+namespace simgrid {
+namespace unw {
+
+XBT_PRIVATE unw_addr_space_t create_addr_space();
+XBT_PRIVATE void* create_context(unw_addr_space_t as, pid_t pid);
+
+}
+}
 
 SG_BEGIN_DECL()
 
 // ***** Libunwind namespace
 
-/** Virtual table for our `libunwind-process_vm_readv` implementation.
- *
- *  This implementation reuse most the code of `libunwind-ptrace` but
- *  does not use ptrace() to read the target process memory by
- *  `process_vm_readv()` or `/dev/${pid}/mem` if possible.
- *
- *  Does not support any MC-specific behaviour (privatisation, snapshots)
- *  and `ucontext_t`.
- *
- *  It works with `void*` contexts allocated with `_UPT_create(pid)`.
- */
-extern XBT_PRIVATE unw_accessors_t mc_unw_vmread_accessors;
-
 /** Virtual table for our `libunwind` implementation
  *
  *  Stack unwinding on a `simgrid::mc::Process*` (for memory, unwinding information)
diff --git a/src/mc/mc_unw_vmread.cpp b/src/mc/mc_unw_vmread.cpp
index 29b015be8f..7082dd3849 100644
--- a/src/mc/mc_unw_vmread.cpp
+++ b/src/mc/mc_unw_vmread.cpp
@@ -11,10 +11,9 @@
 #include <libunwind.h>
 #include <libunwind-ptrace.h>
 
+#include "src/mc/Process.hpp"
 #include "src/mc/mc_unw.h"
 
-extern "C" {
-
 /** \file
  *  Libunwind namespace implementation using process_vm_readv.
  *.
@@ -23,9 +22,9 @@ extern "C" {
 
 /** Partial structure of libunwind-ptrace context in order to get the PID
  *
- *  The context type for libunwind-race is an opaque type. We need to get the
- *  PID which is the first field. This is a hack which might break if the
- *  libunwind-ptrace structure changes.
+ *  HACK, The context type for libunwind-race is an opaque type.
+ *  We need to get the PID which is the first field. This is a hack
+ *  which might break if the libunwind-ptrace structure changes.
  */
 struct _UPT_info {
   pid_t pid;
@@ -101,16 +100,42 @@ static int access_mem(const unw_addr_space_t as,
   return _UPT_access_mem(as, addr, valp, write, arg);
 }
 
-unw_accessors_t mc_unw_vmread_accessors =
-  {
-    &_UPT_find_proc_info,
-    &_UPT_put_unwind_info,
-    &_UPT_get_dyn_info_list_addr,
-    &access_mem,
-    &_UPT_access_reg,
-    &_UPT_access_fpreg,
-    &_UPT_resume,
-    &_UPT_get_proc_name
-  };
+namespace simgrid {
+namespace unw {
+
+/** Virtual table for our `libunwind-process_vm_readv` implementation.
+ *
+ *  This implementation reuse most the code of `libunwind-ptrace` but
+ *  does not use ptrace() to read the target process memory by
+ *  `process_vm_readv()` or `/dev/${pid}/mem` if possible.
+ *
+ *  Does not support any MC-specific behaviour (privatisation, snapshots)
+ *  and `ucontext_t`.
+ *
+ *  It works with `void*` contexts allocated with `_UPT_create(pid)`.
+ */
+// TODO, we could get rid of this if we properly stop the model-checked
+// process before reading the memory.
+static unw_accessors_t accessors = {
+  &_UPT_find_proc_info,
+  &_UPT_put_unwind_info,
+  &_UPT_get_dyn_info_list_addr,
+  &access_mem,
+  &_UPT_access_reg,
+  &_UPT_access_fpreg,
+  &_UPT_resume,
+  &_UPT_get_proc_name
+};
+
+unw_addr_space_t create_addr_space()
+{
+  return unw_create_addr_space(&accessors, __BYTE_ORDER);
+}
+
+void* create_context(unw_addr_space_t as, pid_t pid)
+{
+  return _UPT_create(pid);
+}
 
 }
+}
\ No newline at end of file