Use general instruction/stack pointer convenience method instead of manually

finding the instruction/stack pointer for exploitability rating.

There was already a method that found the instruction pointer, so the files
for exploitability ratings had repeated code. Also a method for finding the
stack pointer is implemented in this CL.

R=ivanpe@chromium.org

Review URL: https://codereview.chromium.org/1210943005

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1468 4c0a9323-5329-0410-9bdc-e9ce6186880e

3 files changed, 55 insertions, 33 deletions

diff --git a/src/processor/dump_context.cc b/src/processor/dump_context.cc
index cadf93f7..612556a2 100644
--- a/src/processor/dump_context.cc
+++ b/src/processor/dump_context.cc
@@ -185,6 +185,49 @@ bool DumpContext::GetInstructionPointer(uint64_t* ip) const {
   return true;
 }
 
+bool DumpContext::GetStackPointer(uint64_t* sp) const {
+  BPLOG_IF(ERROR, !sp) << "DumpContext::GetStackPointer requires |sp|";
+  assert(sp);
+  *sp = 0;
+
+  if (!valid_) {
+    BPLOG(ERROR) << "Invalid DumpContext for GetStackPointer";
+    return false;
+  }
+
+  switch (GetContextCPU()) {
+  case MD_CONTEXT_AMD64:
+    *sp = GetContextAMD64()->rsp;
+    break;
+  case MD_CONTEXT_ARM:
+    *sp = GetContextARM()->iregs[MD_CONTEXT_ARM_REG_SP];
+    break;
+  case MD_CONTEXT_ARM64:
+    *sp = GetContextARM64()->iregs[MD_CONTEXT_ARM64_REG_SP];
+    break;
+  case MD_CONTEXT_PPC:
+    *sp = GetContextPPC()->gpr[MD_CONTEXT_PPC_REG_SP];
+    break;
+  case MD_CONTEXT_PPC64:
+    *sp = GetContextPPC64()->gpr[MD_CONTEXT_PPC64_REG_SP];
+    break;
+  case MD_CONTEXT_SPARC:
+    *sp = GetContextSPARC()->g_r[MD_CONTEXT_SPARC_REG_SP];
+    break;
+  case MD_CONTEXT_X86:
+    *sp = GetContextX86()->esp;
+    break;
+  case MD_CONTEXT_MIPS:
+    *sp = GetContextMIPS()->iregs[MD_CONTEXT_MIPS_REG_SP];
+    break;
+  default:
+    // This should never happen.
+    BPLOG(ERROR) << "Unknown CPU architecture in GetStackPointer";
+    return false;
+  }
+  return true;
+}
+
 void DumpContext::SetContextFlags(uint32_t context_flags) {
   context_flags_ = context_flags;
 }
diff --git a/src/processor/exploitability_linux.cc b/src/processor/exploitability_linux.cc
index 875df165..b5dc0e87 100644
--- a/src/processor/exploitability_linux.cc
+++ b/src/processor/exploitability_linux.cc
@@ -37,8 +37,8 @@
 #include "processor/exploitability_linux.h"
 
 #include "google_breakpad/common/minidump_exception_linux.h"
-#include "google_breakpad/processor/process_state.h"
 #include "google_breakpad/processor/call_stack.h"
+#include "google_breakpad/processor/process_state.h"
 #include "google_breakpad/processor/stack_frame.h"
 #include "processor/logging.h"
 
@@ -98,26 +98,9 @@ ExploitabilityRating ExploitabilityLinux::CheckPlatformExploitability() {
     return EXPLOITABILITY_ERR_PROCESSING;
   }
 
-  // Getting instruction pointer based off architecture.
-  uint32_t architecture = context->GetContextCPU();
-  switch (architecture) {
-    case MD_CONTEXT_X86:
-      instruction_ptr = context->GetContextX86()->eip;
-      break;
-    case MD_CONTEXT_AMD64:
-      instruction_ptr = context->GetContextAMD64()->rip;
-      break;
-    case MD_CONTEXT_ARM:
-      instruction_ptr =
-          context->GetContextARM()->iregs[MD_CONTEXT_ARM_REG_PC];
-      break;
-    case MD_CONTEXT_ARM64:
-      instruction_ptr =
-          context->GetContextARM64()->iregs[MD_CONTEXT_ARM64_REG_PC];
-      break;
-    default:
-      BPLOG(INFO) << "Unsupported architecture.";
-      return EXPLOITABILITY_ERR_PROCESSING;
+  // Getting the instruction pointer.
+  if (!context->GetInstructionPointer(&instruction_ptr)) {
+    return EXPLOITABILITY_ERR_PROCESSING;
   }
 
   // Checking for the instruction pointer in a valid instruction region.
diff --git a/src/processor/exploitability_win.cc b/src/processor/exploitability_win.cc
index 8a444eb2..a1f8703a 100644
--- a/src/processor/exploitability_win.cc
+++ b/src/processor/exploitability_win.cc
@@ -106,18 +106,14 @@ ExploitabilityRating ExploitabilityWin::CheckPlatformExploitability() {
   uint64_t stack_ptr = 0;
   uint64_t instruction_ptr = 0;
 
-  switch (context->GetContextCPU()) {
-    case MD_CONTEXT_X86:
-      stack_ptr = context->GetContextX86()->esp;
-      instruction_ptr = context->GetContextX86()->eip;
-      break;
-    case MD_CONTEXT_AMD64:
-      stack_ptr = context->GetContextAMD64()->rsp;
-      instruction_ptr = context->GetContextAMD64()->rip;
-      break;
-    default:
-      BPLOG(INFO) << "Unsupported architecture.";
-      return EXPLOITABILITY_ERR_PROCESSING;
+  // Getting the instruction pointer.
+  if (!context->GetInstructionPointer(&instruction_ptr)) {
+    return EXPLOITABILITY_ERR_PROCESSING;
+  }
+
+  // Getting the stack pointer.
+  if (!context->GetStackPointer(&stack_ptr)) {
+    return EXPLOITABILITY_ERR_PROCESSING;
   }
 
   // Check if we are executing on the stack.