commit 2a6955e040f24b31a2dfe829f47e35ac91733489
author Dimitry Ivanov <dimitry@google.com> Thu Feb 23 11:53:43 2017 -0800
committer Dimitry Ivanov <dimitry@google.com> Fri Feb 24 16:56:38 2017 -0800
tree e91c30cf688ab2fd0d55546042d3496f489db7de
parent 5927b04ce7d9d4727a4a644f8af4040b8dab5d0a

loader: set PT_INTERP to itself

Some versions of kernel set AT_BASE to 0
if dynamic loader does not have PT_INTERP
set.

Bug: http://b/30739481
Test: run /system/bin/linker64 and /system/bin/linker
Change-Id: I1b67777166fe917d3ee1a97277045ca6f5db0084

linker/Android.bp

diff --git a/linker/Android.bp b/linker/Android.bp
index aab05b4..a43f8b3 100644
--- a/linker/Android.bp
+++ b/linker/Android.bp
@@ -39,29 +39,35 @@
             srcs: ["arch/arm/begin.S"],
 
             cflags: ["-D__work_around_b_24465209__"],
+            ldflags: ["-Wl,-dynamic-linker,/system/bin/linker"],
         },
         arm64: {
             srcs: ["arch/arm64/begin.S"],
+            ldflags: ["-Wl,-dynamic-linker,/system/bin/linker64"],
         },
         x86: {
             srcs: ["arch/x86/begin.c"],
 
             cflags: ["-D__work_around_b_24465209__"],
+            ldflags: ["-Wl,-dynamic-linker,/system/bin/linker"],
         },
         x86_64: {
             srcs: ["arch/x86_64/begin.S"],
+            ldflags: ["-Wl,-dynamic-linker,/system/bin/linker64"],
         },
         mips: {
             srcs: [
                 "arch/mips/begin.S",
                 "linker_mips.cpp",
             ],
+            ldflags: ["-Wl,-dynamic-linker,/system/bin/linker"],
         },
         mips64: {
             srcs: [
                 "arch/mips64/begin.S",
                 "linker_mips.cpp",
             ],
+            ldflags: ["-Wl,-dynamic-linker,/system/bin/linker64"],
         },
     },
 

linker/linker_main.cpp

diff --git a/linker/linker_main.cpp b/linker/linker_main.cpp
index d52b1d6..d037a18 100644
--- a/linker/linker_main.cpp
+++ b/linker/linker_main.cpp
@@ -496,7 +496,7 @@
   // see also https://code.google.com/p/android/issues/detail?id=63174
   if (reinterpret_cast<ElfW(Addr)>(&_start) == entry_point) {
     __libc_format_fd(STDOUT_FILENO,
-                     "This is %s, the helper program for shared library executables.\n",
+                     "This is %s, the helper program for dynamic executables.\n",
                      args.argv[0]);
     exit(0);
   }

tests/dl_test.cpp

diff --git a/tests/dl_test.cpp b/tests/dl_test.cpp
index 74c7b51..ee9b2e1 100644
--- a/tests/dl_test.cpp
+++ b/tests/dl_test.cpp
@@ -24,6 +24,8 @@
 
 #include <string>
 
+#include "utils.h"
+
 extern "C" int main_global_default_serial() {
   return 3370318;
 }
@@ -69,4 +71,19 @@
   ASSERT_EQ(3370318, lib_global_protected_get_serial());
 }
 
+TEST(dl, exec_linker) {
+#if defined(__BIONIC__)
+#if defined(__LP64__)
+  static constexpr const char* kPathToLinker = "/system/bin/linker64";
+#else
+  static constexpr const char* kPathToLinker = "/system/bin/linker";
+#endif
+  ExecTestHelper eth;
+  std::string expected_output = std::string("This is ") + kPathToLinker +
+                                ", the helper program for dynamic executables.\n";
+  eth.SetArgs( { kPathToLinker, nullptr });
+  eth.Run([&]() { execve(kPathToLinker, eth.GetArgs(), eth.GetEnv()); }, 0, expected_output.c_str());
+#endif
+}
+
 // TODO: Add tests for LD_PRELOADs