commit c87f65d2cd0690d81665f8b241c1d763f72b6f80
author Dmitriy Ivanov <dimitry@google.com> Mon May 19 15:06:58 2014 -0700
committer Dmitriy Ivanov <dimitry@google.com> Fri Oct 31 17:04:00 2014 -0700
tree 3b2aa8f9f5db41455b221109c33d8f20f85778b5
parent 210ff1b27b67bd2aa29b35a46f48430b7714a802

Add RTLD_NODELETE flag support

Bug: 18186310
Bug: https://code.google.com/p/android/issues/detail?id=64069

(cherry picked from commit 1b20dafdbe65e43b9f4c95057e8482380833ea91)

Change-Id: Ic02eec22a7c322ece65eb40730a3404f611526b1

linker/linker.cpp

diff --git a/linker/linker.cpp b/linker/linker.cpp
index d918bb5..7b27cd7 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -987,6 +987,11 @@
 }
 
 static void soinfo_unload(soinfo* si) {
+  if (!si->can_unload()) {
+    TRACE("not unloading '%s' - the binary is flagged with NODELETE", si->name);
+    return;
+  }
+
   if (si->ref_count == 1) {
     TRACE("unloading '%s'", si->name);
     si->CallDestructors();
@@ -1045,7 +1050,7 @@
 }
 
 soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo) {
-  if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL|RTLD_NOLOAD)) != 0) {
+  if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL|RTLD_NODELETE|RTLD_NOLOAD)) != 0) {
     DL_ERR("invalid flags to dlopen: %x", flags);
     return nullptr;
   }
@@ -1808,6 +1813,9 @@
   return strtab + index;
 }
 
+bool soinfo::can_unload() const {
+  return (rtld_flags & (RTLD_NODELETE | RTLD_GLOBAL)) == 0;
+}
 /* Force any of the closed stdin, stdout and stderr to be associated with
    /dev/null. */
 static int nullify_closed_stdio() {
@@ -2076,9 +2084,13 @@
         if ((d->d_un.d_val & DF_1_GLOBAL) != 0) {
           rtld_flags |= RTLD_GLOBAL;
         }
+
+        if ((d->d_un.d_val & DF_1_NODELETE) != 0) {
+          rtld_flags |= RTLD_NODELETE;
+        }
         // TODO: Implement other flags
 
-        if ((d->d_un.d_val & ~(DF_1_NOW | DF_1_GLOBAL)) != 0) {
+        if ((d->d_un.d_val & ~(DF_1_NOW | DF_1_GLOBAL | DF_1_NODELETE)) != 0) {
           DL_WARN("Unsupported flags DT_FLAGS_1=%p", reinterpret_cast<void*>(d->d_un.d_val));
         }
         break;

linker/linker.h

diff --git a/linker/linker.h b/linker/linker.h
index 6329efd..ebb4793 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -134,7 +134,7 @@
 #endif
 
   soinfo* next;
-  unsigned flags;
+  uint32_t flags;
 
  private:
   const char* strtab;
@@ -143,8 +143,8 @@
 
   size_t nbucket;
   size_t nchain;
-  unsigned* bucket;
-  unsigned* chain;
+  uint32_t* bucket;
+  uint32_t* chain;
 
 #if defined(__mips__) || !defined(__LP64__)
   // This is only used by mips and mips64, but needs to be here for
@@ -179,12 +179,12 @@
 
 #if defined(__arm__)
   // ARM EABI section used for stack unwinding.
-  unsigned* ARM_exidx;
+  uint32_t* ARM_exidx;
   size_t ARM_exidx_count;
 #elif defined(__mips__)
-  unsigned mips_symtabno;
-  unsigned mips_local_gotno;
-  unsigned mips_gotsym;
+  uint32_t mips_symtabno;
+  uint32_t mips_local_gotno;
+  uint32_t mips_gotsym;
 #endif
 
   size_t ref_count;
@@ -224,10 +224,12 @@
   ElfW(Addr) resolve_symbol_address(ElfW(Sym)* s);
 
   const char* get_string(ElfW(Word) index) const;
+  bool can_unload() const;
 
   bool inline has_min_version(uint32_t min_version) const {
     return (flags & FLAG_NEW_SOINFO) != 0 && version >= min_version;
   }
+
  private:
   void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse);
   void CallFunction(const char* function_name, linker_function_t function);
@@ -258,7 +260,7 @@
   friend soinfo* get_libdl_info();
 };
 
-extern soinfo* get_libdl_info();
+soinfo* get_libdl_info();
 
 void do_android_get_LD_LIBRARY_PATH(char*, size_t);
 void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path);