[osv-dev] [PATCH 1/2] Lookup symbol deeper

[Zhiting Zhu]

dlsym function doesn't seem to lookup symbol deep enough. This
patch fixes test_dlsym_from_sofile_with_preload and
dlsym_with_dependencies

Signed-off-by: Waldemar Kozaczuk <jwkozac...@gmail.com>
Signed-off-by: Zhiting Zhu <zhiti...@cs.utexas.edu>
---
 core/elf.cc        | 14 ++++++++++++++
 include/osv/elf.hh |  1 +
 libc/dlfcn.cc      |  2 +-
 tests/tst-dlfcn.cc |  2 +-
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/core/elf.cc b/core/elf.cc
index 73834b19..26a25c43 100644
--- a/core/elf.cc
+++ b/core/elf.cc
@@ -950,6 +950,20 @@ Elf64_Sym* object::lookup_symbol(const char* name, bool 
self_lookup)
     return sym;
 }
 
+symbol_module object::lookup_symbol_deep(const char* name)
+{
+    symbol_module sym = { lookup_symbol(name, false), this };
+    if (!sym.symbol) {
+        for (auto&& _obj : _needed) {
+            sym = _obj->lookup_symbol_deep(name);
+            if (sym.symbol) {
+                break;
+            }
+        }
+    }
+    return sym;
+}
+
 unsigned object::symtab_len()
 {
     if (dynamic_exists(DT_HASH)) {
diff --git a/include/osv/elf.hh b/include/osv/elf.hh
index 1dac6c08..8cd7b37a 100644
--- a/include/osv/elf.hh
+++ b/include/osv/elf.hh
@@ -347,6 +347,7 @@ public:
     void* base() const;
     void* end() const;
     Elf64_Sym* lookup_symbol(const char* name, bool self_lookup);
+    symbol_module lookup_symbol_deep(const char* name);
     void load_segments();
     void process_headers();
     void unload_segments();
diff --git a/libc/dlfcn.cc b/libc/dlfcn.cc
index 346cf195..e3a4a577 100644
--- a/libc/dlfcn.cc
+++ b/libc/dlfcn.cc
@@ -74,7 +74,7 @@ void* dlsym(void* handle, const char* name)
         abort();
     } else {
         auto obj = *reinterpret_cast<std::shared_ptr<elf::object>*>(handle);
-        sym = { obj->lookup_symbol(name, false), obj.get() };
+        sym = obj->lookup_symbol_deep(name);
     }
     if (!sym.obj || !sym.symbol) {
         dlerror_fmt("dlsym: symbol %s not found", name);
diff --git a/tests/tst-dlfcn.cc b/tests/tst-dlfcn.cc
index 5258256a..6d91fb93 100644
--- a/tests/tst-dlfcn.cc
+++ b/tests/tst-dlfcn.cc
@@ -13,7 +13,7 @@
 namespace utf = boost::unit_test;
 
 const bool rtld_next = false;
-const bool deep_lookup = false;
+const bool deep_lookup = true;
 
 static bool called = false;
 extern "C" void DlSymTestFunction()
-- 
2.17.1

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