diff --git a/Libraries/LibC/Makefile b/Libraries/LibC/Makefile index 718ca90db5..2a79f519ac 100644 --- a/Libraries/LibC/Makefile +++ b/Libraries/LibC/Makefile @@ -56,7 +56,11 @@ LIBC_OBJS = \ syslog.o \ cxxabi.o -OBJS = $(AK_OBJS) $(LIBC_OBJS) +ELF_OBJS = \ + ../LibELF/ELFDynamicObject.o \ + ../LibELF/ELFImage.o + +OBJS = $(AK_OBJS) $(LIBC_OBJS) $(ELF_OBJS) EXTRA_OBJS = setjmp.ao crti.ao crtn.ao diff --git a/Libraries/LibC/dlfcn.cpp b/Libraries/LibC/dlfcn.cpp index 7efb88d2c1..200f0a7262 100644 --- a/Libraries/LibC/dlfcn.cpp +++ b/Libraries/LibC/dlfcn.cpp @@ -1,29 +1,103 @@ #include #include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +// NOTE: The string here should never include a trailing newline (according to POSIX) +String g_dlerror_msg; + +HashMap> g_elf_objects; extern "C" { int dlclose(void*) { - ASSERT_NOT_REACHED(); - return 0; + g_dlerror_msg = "dlclose not implemented!"; + return -1; } char* dlerror() { - ASSERT_NOT_REACHED(); - return nullptr; + return const_cast(g_dlerror_msg.characters()); } -void* dlopen(const char*, int) +void* dlopen(const char* filename, int flags) { - ASSERT_NOT_REACHED(); - return nullptr; + // FIXME: Create a global mutex/semaphore/lock for dlopen/dlclose/dlsym and (?) dlerror + // FIXME: refcount? + + if (!filename) { + // FIXME: Return the handle for "the main executable" + // The Serenity Kernel will keep a mapping of the main elf binary resident in memory, + // But a future dynamic loader might have a different idea/way of letting us access this information + ASSERT_NOT_REACHED(); + } + + FileSystemPath file_path(filename); + + auto existing_elf_object = g_elf_objects.get(file_path.basename()); + if (existing_elf_object.has_value()) { + void* referenced_object = existing_elf_object.value().leak_ref(); + return referenced_object; + } + + int fd = open(filename, O_RDONLY); + if (!fd) { + g_dlerror_msg = String::format("Unable to open file %s", filename); + return nullptr; + } + + ScopeGuard close_fd_guard([fd]() { close(fd); }); + + struct stat file_stats{}; + + int ret = fstat(fd, &file_stats); + if (ret < 0) { + g_dlerror_msg = String::format("Unable to stat file %s", filename); + return nullptr; + } + + auto image = ELFDynamicObject::construct(filename, fd, file_stats.st_size); + + if (!image->is_valid()) { + g_dlerror_msg = String::format("%s is not a valid ELF dynamic shared object!", filename); + return nullptr; + } + + if (!image->load(flags)) { + g_dlerror_msg = String::format("Failed to load ELF object %s", filename); + return nullptr; + } + + g_elf_objects.set(file_path.basename(), move(image)); + g_dlerror_msg = "Successfully loaded ELF object."; + + // we have one refcount already + return g_elf_objects.get(file_path.basename()).value().ptr(); } -void* dlsym(void*, const char*) +void* dlsym(void* handle, const char* symbol_name) { - ASSERT_NOT_REACHED(); - return nullptr; -} + // FIXME: When called with a NULL handle we're supposed to search every dso in the process... that'll get expensive + ASSERT(handle); + auto* dso = reinterpret_cast(handle); + void* symbol = dso->symbol_for_name(symbol_name); + if (!symbol) { + g_dlerror_msg = "Symbol not found"; + return nullptr; + } + return symbol; } + +} // extern "C"