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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <assert.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <AK/HashMap.h>
#include <AK/LexicalPath.h>
#include <AK/RefPtr.h>
#include <AK/ScopeGuard.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <LibELF/DynamicLoader.h>
// NOTE: The string here should never include a trailing newline (according to POSIX)
String g_dlerror_msg;
HashMap<String, RefPtr<ELF::DynamicLoader>> g_elf_objects;
extern "C" {
int dlclose(void*)
{
g_dlerror_msg = "dlclose not implemented!";
return -1;
}
char* dlerror()
{
return const_cast<char*>(g_dlerror_msg.characters());
}
void* dlopen(const char* filename, int flags)
{
// 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();
}
auto basename = LexicalPath(filename).basename();
auto existing_elf_object = g_elf_objects.get(basename);
if (existing_elf_object.has_value()) {
return const_cast<ELF::DynamicLoader*>(existing_elf_object.value());
}
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 loader = ELF::DynamicLoader::construct(filename, fd, file_stats.st_size);
if (!loader->is_valid()) {
g_dlerror_msg = String::format("%s is not a valid ELF dynamic shared object!", filename);
return nullptr;
}
if (!loader->load_from_image(flags,
0 // total_tls_size = 0, FIXME: Support TLS when using dlopen()
)) {
g_dlerror_msg = String::format("Failed to load ELF object %s", filename);
return nullptr;
}
g_elf_objects.set(basename, move(loader));
g_dlerror_msg = "Successfully loaded ELF object.";
// we have one refcount already
return const_cast<ELF::DynamicLoader*>(g_elf_objects.get(basename).value());
}
void* dlsym(void* handle, const char* symbol_name)
{
// 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<ELF::DynamicLoader*>(handle);
void* symbol = dso->symbol_for_name(symbol_name);
if (!symbol) {
g_dlerror_msg = "Symbol not found";
return nullptr;
}
return symbol;
}
} // extern "C"
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