support elfloader for shared object and relocatable object
1. elfloader for shared object example: TencentOS-tiny\examples\elfloader_shared_object keil: TencentOS-tiny\board\TencentOS_tiny_EVB_MX_Plus\KEIL\elfloader_shared_object 2. elfloader for relocatable object: example: TencentOS-tiny\examples\elfloader_relocatable_object keil: TencentOS-tiny\board\TencentOS_tiny_EVB_MX_Plus\KEIL\elfloader_relocatable_object 3. TODO: - add icache/dcache flush when module is loaded - support more relocation type in elfloader_arch_relocate
This commit is contained in:
daishengdong
353
components/elfloader/shared_object/tos_elfloader_shared_object.c
Normal file
353
components/elfloader/shared_object/tos_elfloader_shared_object.c
Normal file
@@ -0,0 +1,353 @@
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/*----------------------------------------------------------------------------
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* Tencent is pleased to support the open source community by making TencentOS
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* available.
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*
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* Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
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* If you have downloaded a copy of the TencentOS binary from Tencent, please
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* note that the TencentOS binary is licensed under the BSD 3-Clause License.
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*
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* If you have downloaded a copy of the TencentOS source code from Tencent,
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* please note that TencentOS source code is licensed under the BSD 3-Clause
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* License, except for the third-party components listed below which are
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* subject to different license terms. Your integration of TencentOS into your
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* own projects may require compliance with the BSD 3-Clause License, as well
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* as the other licenses applicable to the third-party components included
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* within TencentOS.
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*---------------------------------------------------------------------------*/
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#include "tos_elfloader.h"
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__STATIC__ void *local_symtab_lookup(int fd, int32_t load_bias, char *sym_name,
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uint32_t symtab_offset, uint32_t symtab_size, uint32_t symtab_entsize,
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uint32_t strtab_offset)
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{
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int i = 0;
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elf32_sym_t sym;
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#define SYMBOL_NAME_MAX 30
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static char name[SYMBOL_NAME_MAX];
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for (i = 0; i < symtab_size / symtab_entsize; ++i) {
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if (elfloader_fd_read(fd, symtab_offset, &sym, sizeof(elf32_sym_t)) != ELFLOADER_ERR_NONE) {
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return K_NULL;
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}
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if (sym.st_name) {
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if (elfloader_fd_read(fd, strtab_offset + sym.st_name, name, sizeof(name)) != ELFLOADER_ERR_NONE) {
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return K_NULL;
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}
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if (strcmp(name, sym_name) == 0) {
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return (void *)(sym.st_value + load_bias);
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}
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}
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symtab_offset += symtab_entsize;
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}
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return K_NULL;
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}
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__STATIC__ el_err_t elfloader_relocate(int fd, int32_t load_bias,
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uint32_t rel_offset, uint32_t rel_size, uint32_t rel_entsize,
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uint32_t symtab_offset, uint32_t symtab_size, uint32_t symtab_entsize,
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uint32_t strtab_offset, uint32_t strtab_size)
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{
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int i = 0;
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elf32_rela_t rela;
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elf32_sym_t sym;
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void *addr;
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#define SYMBOL_NAME_MAX 30
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static char name[SYMBOL_NAME_MAX];
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int is_rela = (rel_entsize == sizeof(elf32_rela_t) ? K_TRUE : K_FALSE);
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for (i = 0; i < rel_size / rel_entsize; ++i) {
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addr = K_NULL;
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if (elfloader_fd_read(fd, rel_offset, &rela, rel_entsize) != ELFLOADER_ERR_NONE) {
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return ELFLOADER_ERR_FD_READ_FAILED;
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}
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if (elfloader_fd_read(fd,
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symtab_offset + ELF32_R_SYM(rela.r_info) * symtab_entsize,
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&sym,
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symtab_entsize) != ELFLOADER_ERR_NONE) {
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return ELFLOADER_ERR_FD_READ_FAILED;
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}
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/* load the symbol's name */
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if (elfloader_fd_read(fd,
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strtab_offset + sym.st_name,
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name,
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sizeof(name)) != ELFLOADER_ERR_NONE) {
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return ELFLOADER_ERR_FD_READ_FAILED;
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}
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/* an external symbol, or a weak one */
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if (sym.st_shndx == SHN_UNDEF ||
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ELF32_SYM_TYPE(sym.st_info) == STB_WEAK) {
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/* look up in the global symbol table */
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addr = elfloader_symtab_lookup(name);
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}
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/* an external symbol but not found in the global symbol table */
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if (sym.st_shndx == SHN_UNDEF && !addr) {
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return ELFLOADER_ERR_SYM_NOT_FOUND;
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}
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/* an internal symbol, or a weak symbol without STRONG one in global symbol table */
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if (!addr) {
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addr = local_symtab_lookup(fd, load_bias, name,
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symtab_offset, symtab_size, symtab_entsize,
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strtab_offset);
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}
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/* still not found */
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if (!addr) {
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return ELFLOADER_ERR_SYM_NOT_FOUND;
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}
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elfloader_arch_relocate(rela.r_offset + load_bias, load_bias, (uint32_t)addr, &rela, is_rela);
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rel_offset += rel_entsize;
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}
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return ELFLOADER_ERR_NONE;
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}
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__API__ el_err_t tos_elfloader_load(el_module_t *module, int fd)
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{
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int i = 0;
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el_err_t err;
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elf32_ehdr_t ehdr;
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elf32_shdr_t shdr;
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elf32_dyn_t dyn;
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elf32_phdr_t phdr;
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void *base = K_NULL, *addr_seg2cp; /* ram base for LOAD segments */
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int32_t load_bias;
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uint32_t shdr_offset, phdr_offset;
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uint32_t vaddr_start = (uint32_t)-1, vaddr_end = 0;
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uint32_t dyn_offset, dyn_size = 0, dyn_entsize;
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uint32_t strtab_offset, strtab_size = 0;
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uint32_t symtab_offset, symtab_size = 0, symtab_entsize;
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uint32_t rel_entsize;
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uint32_t rel_dyn_offset, rel_dyn_size = 0;
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uint32_t rel_plt_offset, rel_plt_size = 0;
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if (!module) {
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return ELFLOADER_ERR_PTR_NULL;
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}
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memset(module, 0, sizeof(el_module_t));
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/* read the elf header */
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if (elfloader_fd_read(fd, 0, &ehdr, sizeof(elf32_ehdr_t)) != ELFLOADER_ERR_NONE) {
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return ELFLOADER_ERR_FD_READ_FAILED;
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}
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/* sanity check, magic verify */
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if (memcmp(ehdr.e_ident, elf_header_magic, sizeof(elf_header_magic)) != 0) {
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return ELFLOADER_ERR_HEADER_INVALID;
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}
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/* it should be a shared object */
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if (ehdr.e_type != ET_DYN) {
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return ELFLOADER_ERR_TYPE_INVALID;
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}
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shdr_offset = ehdr.e_shoff;
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for (i = 0; i < ehdr.e_shnum; ++i) {
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if (elfloader_fd_read(fd, shdr_offset, &shdr, sizeof(elf32_shdr_t)) != ELFLOADER_ERR_NONE) {
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return ELFLOADER_ERR_FD_READ_FAILED;
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}
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if (shdr.sh_type == SHT_DYNAMIC) { /* dynamic section, .dynamic */
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dyn_offset = shdr.sh_offset;
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dyn_size = shdr.sh_size;
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dyn_entsize = shdr.sh_entsize;
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} else if (shdr.sh_type == SHT_DYNSYM) { /* .dynsym */
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symtab_size = shdr.sh_size;
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}
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shdr_offset += ehdr.e_shentsize;
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}
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if (dyn_size == 0) {
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return ELFLOADER_ERR_NO_DYN;
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}
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if (symtab_size == 0) {
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return ELFLOADER_ERR_NO_SYMTAB;
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}
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for (i = 0; i < dyn_size / dyn_entsize; ++i) {
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if (elfloader_fd_read(fd, dyn_offset, &dyn, sizeof(elf32_dyn_t)) != ELFLOADER_ERR_NONE) {
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return ELFLOADER_ERR_FD_READ_FAILED;
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}
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if (dyn.d_tag == DT_NULL) {
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break;
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} else if (dyn.d_tag == DT_SYMTAB) { /* dynamic symbol table */
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symtab_offset = dyn.d_un.d_ptr;
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} else if (dyn.d_tag == DT_SYMENT) { /* entry size of symbol table */
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symtab_entsize = dyn.d_un.d_val;
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} else if (dyn.d_tag == DT_STRTAB) { /* dynamic string table */
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strtab_offset = dyn.d_un.d_ptr;
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} else if (dyn.d_tag == DT_STRSZ) { /* size of dynamic string table */
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strtab_size = dyn.d_un.d_val;
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} else if (dyn.d_tag == DT_REL) { /* dynamic relocation table */
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rel_dyn_offset = dyn.d_un.d_ptr;
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} else if (dyn.d_tag == DT_RELSZ) { /* size of rel.dyn */
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rel_dyn_size = dyn.d_un.d_val;
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} else if (dyn.d_tag == DT_RELENT) { /* entry size of rel.dyn */
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rel_entsize = dyn.d_un.d_val;
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} else if (dyn.d_tag == DT_JMPREL) { /* plt relocation table. why NOT DT_PLTREL, confusing */
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rel_plt_offset = dyn.d_un.d_ptr;
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} else if (dyn.d_tag == DT_PLTRELSZ) { /* size of rel.plt */
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rel_plt_size = dyn.d_un.d_val;
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}
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dyn_offset += dyn_entsize;
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}
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if (strtab_size == 0) {
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return ELFLOADER_ERR_NO_STRTAB;
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}
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phdr_offset = ehdr.e_phoff;
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for (i = 0; i < ehdr.e_phnum; ++i) {
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if (elfloader_fd_read(fd, phdr_offset, &phdr, sizeof(elf32_phdr_t)) != ELFLOADER_ERR_NONE) {
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return ELFLOADER_ERR_FD_READ_FAILED;
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}
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if (phdr.p_type == PHT_LOAD) {
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if (phdr.p_vaddr < vaddr_start) {
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vaddr_start = phdr.p_vaddr;
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}
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if (phdr.p_vaddr + phdr.p_memsz > vaddr_end) {
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vaddr_end = phdr.p_vaddr + phdr.p_memsz;
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}
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}
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phdr_offset += ehdr.e_phentsize;
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}
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if (vaddr_start == (uint32_t)-1 || vaddr_end == 0) {
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return ELFLOADER_ERR_NO_LOAD_SEGMENTS;
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}
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/* reserving memory for LOAD segments */
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base = tos_mmheap_aligned_alloc(vaddr_end - vaddr_start, 64);
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if (!base) {
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return ELFLOADER_ERR_OUT_OF_MEMORY;
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}
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load_bias = (uint32_t)base - vaddr_start;
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/* do segments load */
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phdr_offset = ehdr.e_phoff;
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for (i = 0; i < ehdr.e_phnum; ++i) {
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if (elfloader_fd_read(fd, phdr_offset, &phdr, sizeof(elf32_phdr_t)) != ELFLOADER_ERR_NONE) {
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err = ELFLOADER_ERR_FD_READ_FAILED;
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goto OUT;
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}
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if (phdr.p_type == PHT_LOAD) {
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addr_seg2cp = (void *)(load_bias + phdr.p_vaddr);
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if (elfloader_fd_read(fd,
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phdr.p_offset,
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addr_seg2cp,
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phdr.p_filesz) != ELFLOADER_ERR_NONE) {
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err = ELFLOADER_ERR_FD_READ_FAILED;
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goto OUT;
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}
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if (phdr.p_memsz > phdr.p_filesz) {
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/* clear bss */
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memset((void *)((uint8_t *)addr_seg2cp + phdr.p_filesz),
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0,
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phdr.p_memsz - phdr.p_filesz);
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}
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}
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phdr_offset += ehdr.e_phentsize;
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}
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if (rel_dyn_size > 0) {
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err = elfloader_relocate(fd, load_bias,
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rel_dyn_offset, rel_dyn_size, rel_entsize,
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symtab_offset, symtab_size, symtab_entsize,
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strtab_offset, strtab_size);
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if (err != ELFLOADER_ERR_NONE) {
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goto OUT;
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}
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}
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if (rel_plt_size > 0) {
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err = elfloader_relocate(fd, load_bias,
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rel_plt_offset, rel_plt_size, rel_entsize,
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symtab_offset, symtab_size, symtab_entsize,
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strtab_offset, strtab_size);
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if (err != ELFLOADER_ERR_NONE) {
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goto OUT;
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}
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}
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/* TODO: should do icache/dcahe flush here, sth. like:
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dcache_flush();
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icache_flush();
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*/
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module->fd = fd;
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module->base = base;
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module->info.so.load_bias = load_bias;
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module->symtab_offset = symtab_offset;
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module->symtab_size = symtab_size;
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module->symtab_entsize = symtab_entsize;
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module->strtab_offset = strtab_offset;
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return ELFLOADER_ERR_NONE;
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OUT:
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if (base) {
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tos_mmheap_free(base);
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}
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return err;
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}
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__API__ el_err_t tos_elfloader_unload(el_module_t *module)
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{
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if (!module || !module->base) {
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return ELFLOADER_ERR_PTR_NULL;
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}
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tos_mmheap_free(module->base);
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module->base = K_NULL;
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return ELFLOADER_ERR_NONE;
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}
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__API__ void *tos_elfloader_find_symbol(el_module_t *module, char *symbol)
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{
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return local_symtab_lookup(module->fd, module->info.so.load_bias, symbol,
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module->symtab_offset, module->symtab_size, module->symtab_entsize,
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module->strtab_offset);
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}
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