| /* ********************************************************** |
| * Copyright (c) 2011-2014 Google, Inc. All rights reserved. |
| * Copyright (c) 2008-2010 VMware, Inc. All rights reserved. |
| * **********************************************************/ |
| |
| /* |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * |
| * * Redistributions of source code must retain the above copyright notice, |
| * this list of conditions and the following disclaimer. |
| * |
| * * 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. |
| * |
| * * Neither the name of VMware, Inc. nor the names of its contributors may be |
| * used to endorse or promote products derived from this software without |
| * specific prior written permission. |
| * |
| * 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 VMWARE, INC. 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. |
| */ |
| |
| #ifndef MODULE_ELF_H |
| #define MODULE_ELF_H |
| |
| #include <elf.h> /* for ELF types */ |
| |
| /* XXX i#1345: support mixed-mode 32-bit and 64-bit in one process. |
| * There is no official support for that on Linux or Mac and for now we do |
| * not support it either, especially not mixing libraries. |
| */ |
| #ifdef X64 |
| # define ELF_HEADER_TYPE Elf64_Ehdr |
| # define ELF_ALTARCH_HEADER_TYPE Elf32_Ehdr |
| # define ELF_PROGRAM_HEADER_TYPE Elf64_Phdr |
| # define ELF_SECTION_HEADER_TYPE Elf64_Shdr |
| # define ELF_DYNAMIC_ENTRY_TYPE Elf64_Dyn |
| # define ELF_ADDR Elf64_Addr |
| # define ELF_WORD Elf64_Xword |
| # define ELF_HALF Elf64_Half |
| # define ELF_SYM_TYPE Elf64_Sym |
| # define ELF_ST_TYPE ELF64_ST_TYPE |
| # define ELF_WORD_SIZE 64 /* __ELF_NATIVE_CLASS */ |
| # define ELF_ST_BIND ELF64_ST_BIND |
| # define ELF_ST_VISIBILITY ELF64_ST_VISIBILITY |
| # define ELF_REL_TYPE Elf64_Rel |
| # define ELF_RELA_TYPE Elf64_Rela |
| # define ELF_AUXV_TYPE Elf64_auxv_t |
| #else |
| # define ELF_HEADER_TYPE Elf32_Ehdr |
| # define ELF_ALTARCH_HEADER_TYPE Elf64_Ehdr |
| # define ELF_PROGRAM_HEADER_TYPE Elf32_Phdr |
| # define ELF_SECTION_HEADER_TYPE Elf32_Shdr |
| # define ELF_DYNAMIC_ENTRY_TYPE Elf32_Dyn |
| # define ELF_ADDR Elf32_Addr |
| # define ELF_WORD Elf32_Word |
| # define ELF_HALF Elf32_Half |
| # define ELF_SYM_TYPE Elf32_Sym |
| # define ELF_ST_TYPE ELF32_ST_TYPE |
| # define ELF_WORD_SIZE 32 /* __ELF_NATIVE_CLASS */ |
| # define ELF_ST_BIND ELF32_ST_BIND |
| # define ELF_ST_VISIBILITY ELF32_ST_VISIBILITY |
| # define ELF_REL_TYPE Elf32_Rel |
| # define ELF_RELA_TYPE Elf32_Rela |
| # define ELF_AUXV_TYPE Elf32_auxv_t |
| #endif |
| |
| #ifdef X64 |
| /* AMD x86-64 relocations. */ |
| # define ELF_R_TYPE ELF64_R_TYPE |
| # define ELF_R_SYM ELF64_R_SYM |
| # define ELF_R_INFO ELF64_R_INFO |
| /* relocation type */ |
| # define ELF_R_NONE R_X86_64_NONE /* No reloc */ |
| # define ELF_R_DIRECT R_X86_64_64 /* Direct 64 bit */ |
| # define ELF_R_PC32 R_X86_64_PC32 /* PC relative 32-bit signed */ |
| # define ELF_R_COPY R_X86_64_COPY /* copy symbol at runtime */ |
| # define ELF_R_GLOB_DAT R_X86_64_GLOB_DAT /* GOT entry */ |
| # define ELF_R_JUMP_SLOT R_X86_64_JUMP_SLOT /* PLT entry */ |
| # define ELF_R_RELATIVE R_X86_64_RELATIVE /* Adjust by program delta */ |
| # ifndef R_X86_64_IRELATIVE |
| # define R_X86_64_IRELATIVE 37 |
| # endif |
| # define ELF_R_IRELATIVE R_X86_64_IRELATIVE /* Adjust indirectly by program base */ |
| /* TLS hanlding */ |
| # define ELF_R_TLS_DTPMOD R_X86_64_DTPMOD64 /* Module ID */ |
| # define ELF_R_TLS_TPOFF R_X86_64_TPOFF64 /* Offset in module's TLS block */ |
| # define ELF_R_TLS_DTPOFF R_X86_64_DTPOFF64 /* Offset in initial TLS block */ |
| # ifndef R_X86_64_TLSDESC |
| # define R_X86_64_TLSDESC 36 |
| # endif |
| # define ELF_R_TLS_DESC R_X86_64_TLSDESC /* TLS descriptor containing |
| * pointer to code and to |
| * argument, returning the TLS |
| * offset for the symbol. |
| */ |
| #else /* 32-bit */ |
| # define ELF_R_TYPE ELF32_R_TYPE |
| # define ELF_R_SYM ELF32_R_SYM |
| # define ELF_R_INFO ELF32_R_INFO |
| /* relocation type */ |
| # define ELF_R_NONE R_386_NONE /* No reloc */ |
| # define ELF_R_DIRECT R_386_32 /* Direct 32 bit */ |
| # define ELF_R_PC32 R_386_PC32 /* PC relative 32 bit */ |
| # define ELF_R_COPY R_386_COPY /* Copy symbol at runtime */ |
| # define ELF_R_GLOB_DAT R_386_GLOB_DAT /* GOT entry */ |
| # define ELF_R_JUMP_SLOT R_386_JMP_SLOT /* PLT entry */ |
| # define ELF_R_RELATIVE R_386_RELATIVE /* Adjust by program delta */ |
| # ifndef R_386_IRELATIVE |
| # define R_386_IRELATIVE 42 |
| # endif |
| # define ELF_R_IRELATIVE R_386_IRELATIVE /* Adjust indirectly by program base */ |
| /* tls related */ |
| # define ELF_R_TLS_DTPMOD R_386_TLS_DTPMOD32 /* Module ID */ |
| # define ELF_R_TLS_TPOFF R_386_TLS_TPOFF /* Negated offsets in static TLS block */ |
| # define ELF_R_TLS_DTPOFF R_386_TLS_DTPOFF32 /* Offset in TLS block */ |
| # ifndef R_386_TLS_DESC |
| # define R_386_TLS_DESC 41 |
| # endif |
| # define ELF_R_TLS_DESC R_386_TLS_DESC /* TLS descriptor containing |
| * pointer to code and to |
| * argument, returning the TLS |
| * offset for the symbol. |
| */ |
| #endif |
| |
| bool |
| get_elf_platform(file_t f, dr_platform_t *platform); |
| |
| bool |
| is_elf_so_header(app_pc base, size_t size); |
| |
| bool |
| is_elf_partial_map(app_pc base, size_t size, uint memprot); |
| |
| app_pc |
| module_vaddr_from_prog_header(app_pc prog_header, uint num_segments, |
| OUT app_pc *first_end, /* first segment's end */ |
| OUT app_pc *max_end); |
| |
| bool |
| module_read_program_header(app_pc base, |
| uint segment_num, |
| OUT app_pc *segment_base, |
| OUT app_pc *segment_end, |
| OUT uint *segment_prot, |
| OUT size_t *segment_align); |
| |
| ELF_ADDR |
| module_get_section_with_name(app_pc image, size_t img_size, |
| const char *sec_name); |
| |
| void |
| module_relocate_rel(app_pc modbase, |
| os_privmod_data_t *pd, |
| ELF_REL_TYPE *start, |
| ELF_REL_TYPE *end); |
| |
| void |
| module_relocate_rela(app_pc modbase, |
| os_privmod_data_t *pd, |
| ELF_RELA_TYPE *start, |
| ELF_RELA_TYPE *end); |
| |
| bool |
| module_get_relro(app_pc base, OUT app_pc *relro_base, OUT size_t *relro_size); |
| |
| bool |
| module_read_os_data(app_pc base, |
| OUT ptr_int_t *delta, |
| OUT os_module_data_t *os_data, |
| OUT char **soname); |
| |
| uint |
| module_segment_prot_to_osprot(ELF_PROGRAM_HEADER_TYPE *prog_hdr); |
| |
| /* Data structure for loading an ELF. |
| */ |
| typedef struct elf_loader_t { |
| const char *filename; |
| file_t fd; |
| ELF_HEADER_TYPE *ehdr; /* Points into buf. */ |
| ELF_PROGRAM_HEADER_TYPE *phdrs; /* Points into buf or file_map. */ |
| app_pc load_base; /* Load base. */ |
| ptr_int_t load_delta; /* Delta from preferred base. */ |
| size_t image_size; /* Size of the mapped image. */ |
| void *file_map; /* Whole file map, if needed. */ |
| size_t file_size; /* Size of the file map. */ |
| |
| /* Static buffer sized to hold most headers in a single read. A typical ELF |
| * file has an ELF header followed by program headers. On my workstation, |
| * most ELFs in /usr/lib have 7 phdrs, and the maximum is 9. We choose 12 |
| * as a good upper bound and to allow for padding. If the headers don't |
| * fit, we fall back to file mapping. |
| */ |
| byte buf[sizeof(ELF_HEADER_TYPE) + sizeof(ELF_PROGRAM_HEADER_TYPE) * 12]; |
| } elf_loader_t; |
| |
| /* Initialized an ELF loader for use with the given file. */ |
| bool |
| elf_loader_init(elf_loader_t *elf, const char *filename); |
| |
| /* Frees resources needed to load the ELF, not the mapped image itself. */ |
| void |
| elf_loader_destroy(elf_loader_t *elf); |
| |
| /* Reads the main ELF header. */ |
| ELF_HEADER_TYPE * |
| elf_loader_read_ehdr(elf_loader_t *elf); |
| |
| /* Reads the ELF program headers, via read() or mmap() syscalls. */ |
| ELF_PROGRAM_HEADER_TYPE * |
| elf_loader_read_phdrs(elf_loader_t *elf); |
| |
| /* Shorthand to initialize the loader and read the ELF and program headers. */ |
| bool |
| elf_loader_read_headers(elf_loader_t *elf, const char *filename); |
| |
| /* Maps in the entire ELF file, including unmapped portions such as section |
| * headers and debug info. Does not re-map the same file if called twice. |
| */ |
| app_pc |
| elf_loader_map_file(elf_loader_t *elf, bool reachable); |
| |
| /* Maps in the PT_LOAD segments of an ELF file, returning the base. Must be |
| * called after reading program headers with elf_loader_read_phdrs() or the |
| * elf_loader_read_headers() shortcut. All image mappings are done via the |
| * provided function pointers. |
| * |
| * XXX: fixed is only a hint as PIEs with a base of 0 should not use MAP_FIXED, |
| * should we remove it? |
| */ |
| app_pc |
| elf_loader_map_phdrs(elf_loader_t *elf, bool fixed, map_fn_t map_func, |
| unmap_fn_t unmap_func, prot_fn_t prot_func, bool reachable); |
| |
| /* Iterate program headers of a mapped ELF image and find the string that |
| * PT_INTERP points to. Typically this comes early in the file and is always |
| * included in PT_LOAD segments, so we safely do this after the initial |
| * mapping. |
| */ |
| const char * |
| elf_loader_find_pt_interp(elf_loader_t *elf); |
| |
| |
| #endif /* MODULE_ELF_H */ |
