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
aosp-mirror · Feb 25, 2017 · 2a6955e · 2a6955e
1 parent 5927b04
commit 2a6955e
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Showing 3 changed files with 24 additions and 1 deletion.
diff --git a/linker/Android.bp b/linker/Android.bp
@@ -39,29 +39,35 @@ cc_binary {
             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"],
         },
     },
 

diff --git a/linker/linker_main.cpp b/linker/linker_main.cpp
@@ -496,7 +496,7 @@ extern "C" ElfW(Addr) __linker_init(void* raw_args) {
   // 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);
   }

diff --git 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 @@ TEST(dl, lib_does_not_preempt_global_protected) {
   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