linker: support ldd(1)-like behavior via --list.

Given that we have both linker and linker64, I didn't really want to have
to have ldd and ldd64, so this change just adds the --list option to the
linkers and a shell script wrapper "ldd" that calls the appropriate
linker behind the scenes.

Test: adb shell linker --list `which app_process32`
Test: adb shell linker64 --list `which date`
Test: adb shell ldd `which app_process32`
Test: adb shell ldd `which date`
Change-Id: I33494bda1cc3cafee54e091f97c0f2ae52d1f74b

1 files changed, 7 insertions, 0 deletions

diff --git a/linker/linker.cpp b/linker/linker.cpp
index 0de17f780..f68775c19 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -2596,6 +2596,8 @@ bool link_namespaces_all_libs(android_namespace_t* namespace_from,
 }
 
 ElfW(Addr) call_ifunc_resolver(ElfW(Addr) resolver_addr) {
+  if (g_is_ldd) return 0;
+
   typedef ElfW(Addr) (*ifunc_resolver_t)(void);
   ifunc_resolver_t ifunc_resolver = reinterpret_cast<ifunc_resolver_t>(resolver_addr);
   ElfW(Addr) ifunc_addr = ifunc_resolver();
@@ -3876,6 +3878,11 @@ bool soinfo::link_image(const soinfo_list_t& global_group, const soinfo_list_t&
     return true;
   }
 
+  if (g_is_ldd && !is_main_executable()) {
+    async_safe_format_fd(STDOUT_FILENO, "\t%s => %s (%p)\n", get_soname(),
+                         get_realpath(), reinterpret_cast<void*>(base));
+  }
+
   local_group_root_ = local_group.front();
   if (local_group_root_ == nullptr) {
     local_group_root_ = this;