From: Zhiting Zhu <zhiti...@cs.utexas.edu>
Committer: Nadav Har'El <n...@scylladb.com>
Branch: master
Lookup symbol deeper
dlsym function doesn't seem to lookup symbol deep enough. This
patch includes a bfs version of collect dependencies. It
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>
Message-Id: <20200120011727.1736-1-zhiti...@cs.utexas.edu>
---
diff --git a/core/elf.cc b/core/elf.cc
--- a/core/elf.cc
+++ b/core/elf.cc
@@ -27,6 +27,7 @@
#include <sys/utsname.h>
#include <osv/demangle.hh>
#include <boost/version.hpp>
+#include <deque>
#include "arch.hh"
@@ -950,6 +951,22 @@ 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) {
+ auto deps = this->collect_dependencies_bfs();
+ for (auto&& _obj : deps) {
+ auto symbol = _obj->lookup_symbol(name, false);
+ if (symbol) {
+ sym = { symbol, _obj };
+ break;
+ }
+ }
+ }
+ return sym;
+}
+
unsigned object::symtab_len()
{
if (dynamic_exists(DT_HASH)) {
@@ -1089,6 +1106,28 @@ void
object::collect_dependencies(std::unordered_set<elf::object*>& ds)
}
}
+std::deque<elf::object*> object::collect_dependencies_bfs()
+{
+ std::unordered_set<object*> deps_set;
+ std::deque<object*> operate_queue;
+ std::deque<object*> deps;
+ operate_queue.push_back(this);
+ deps_set.insert(this);
+
+ while (!operate_queue.empty()) {
+ object* obj = operate_queue.front();
+ operate_queue.pop_front();
+ deps.push_back(obj);
+ for (auto&& d : obj->_needed) {
+ if (!deps_set.count(d.get())) {
+ deps_set.insert(d.get());
+ operate_queue.push_back(d.get());
+ }
+ }
+ }
+ return deps;
+}
+
std::string object::soname()
{
return dynamic_exists(DT_SONAME) ? dynamic_str(DT_SONAME) : std::string();
diff --git a/include/osv/elf.hh b/include/osv/elf.hh
--- 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();
@@ -405,6 +406,7 @@ private:
void relocate_pltgot();
unsigned symtab_len();
void collect_dependencies(std::unordered_set<elf::object*>& ds);
+ std::deque<elf::object*> collect_dependencies_bfs();
void prepare_initial_tls(void* buffer, size_t size,
std::vector<ptrdiff_t>& offsets);
void prepare_local_tls(std::vector<ptrdiff_t>& offsets);
void alloc_static_tls();
diff --git a/libc/dlfcn.cc b/libc/dlfcn.cc
--- 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
--- 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()
--
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