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 <[email protected]> Signed-off-by: Zhiting Zhu <[email protected]> --- core/elf.cc | 39 +++++++++++++++++++++++++++++++++++++++ include/osv/elf.hh | 2 ++ libc/dlfcn.cc | 2 +- tests/tst-dlfcn.cc | 2 +- 4 files changed, 43 insertions(+), 2 deletions(-) diff --git a/core/elf.cc b/core/elf.cc index 73834b19..a419ea6a 100644 --- 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 index 1dac6c08..c942ac61 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(); @@ -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 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 -- You received this message because you are subscribed to the Google Groups "OSv Development" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/osv-dev/20200120011727.1736-1-zhitingz%40cs.utexas.edu.
