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serenity/Libraries/LibELF/ELFDynamicLoader.h
Andreas Kling 94ca55cefd Meta: Add license header to source files
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.

For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.

Going forward, all new source files should include a license header.
2020-01-18 09:45:54 +01:00

116 lines
4.6 KiB
C++

/*
* 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.
*/
#pragma once
#include <LibELF/ELFDynamicObject.h>
#include <LibELF/ELFImage.h>
#include <LibELF/exec_elf.h>
#include <mman.h>
#include <AK/OwnPtr.h>
#include <AK/RefCounted.h>
#include <AK/String.h>
#define ALIGN_ROUND_UP(x, align) ((((size_t)(x)) + align - 1) & (~(align - 1)))
class ELFDynamicLoader : public RefCounted<ELFDynamicLoader> {
public:
static NonnullRefPtr<ELFDynamicLoader> construct(const char* filename, int fd, size_t file_size);
~ELFDynamicLoader();
bool is_valid() const { return m_valid; }
// Load a full ELF image from file into the current process and create an ELFDynamicObject
// from the SHT_DYNAMIC in the file.
bool load_from_image(unsigned flags);
// Stage 2 of loading: relocations and init functions
// Assumes that the program headers have been loaded and that m_dynamic_object is initialized
// Splitting loading like this allows us to use the same code to relocate a main executable as an elf binary
bool load_stage_2(unsigned flags);
// Intended for use by dlsym or other internal methods
void* symbol_for_name(const char*);
void dump();
// Will be called from _fixup_plt_entry, as part of the PLT trampoline
Elf32_Addr patch_plt_entry(u32 relocation_offset);
private:
class ProgramHeaderRegion {
public:
void set_program_header(const Elf32_Phdr& header) { m_program_header = header; }
// Information from ELF Program header
u32 type() const { return m_program_header.p_type; }
u32 flags() const { return m_program_header.p_flags; }
u32 offset() const { return m_program_header.p_offset; }
VirtualAddress desired_load_address() const { return VirtualAddress(m_program_header.p_vaddr); }
u32 size_in_memory() const { return m_program_header.p_memsz; }
u32 size_in_image() const { return m_program_header.p_filesz; }
u32 alignment() const { return m_program_header.p_align; }
u32 mmap_prot() const;
bool is_readable() const { return flags() & PF_R; }
bool is_writable() const { return flags() & PF_W; }
bool is_executable() const { return flags() & PF_X; }
bool is_tls_template() const { return type() == PT_TLS; }
bool is_load() const { return type() == PT_LOAD; }
bool is_dynamic() const { return type() == PT_DYNAMIC; }
u32 required_load_size() { return ALIGN_ROUND_UP(m_program_header.p_memsz, m_program_header.p_align); }
private:
Elf32_Phdr m_program_header; // Explictly a copy of the PHDR in the image
};
explicit ELFDynamicLoader(const char* filename, int fd, size_t file_size);
explicit ELFDynamicLoader(Elf32_Dyn* dynamic_location, Elf32_Addr load_address);
// Stage 1
void load_program_headers(const ELFImage& elf_image);
// Stage 2
void do_relocations();
void setup_plt_trampoline();
void call_object_init_functions();
String m_filename;
size_t m_file_size { 0 };
int m_image_fd { -1 };
void* m_file_mapping { nullptr };
bool m_valid { true };
OwnPtr<ELFDynamicObject> m_dynamic_object;
VirtualAddress m_text_segment_load_address;
size_t m_text_segment_size;
VirtualAddress m_tls_segment_address;
VirtualAddress m_dynamic_section_address;
};