Shall we commit this and another V4 version of these patches? On Sunday, January 19, 2020 at 8:17:39 PM UTC-5, Zhiting Zhu wrote: > > 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 <jwkoz...@gmail.com <javascript:>> > Signed-off-by: Zhiting Zhu <zhit...@cs.utexas.edu <javascript:>> > --- > 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 > >
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