| /* |
| * Copyright (c) 2015 Travis Geiselbrecht |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining |
| * a copy of this software and associated documentation files |
| * (the "Software"), to deal in the Software without restriction, |
| * including without limitation the rights to use, copy, modify, merge, |
| * publish, distribute, sublicense, and/or sell copies of the Software, |
| * and to permit persons to whom the Software is furnished to do so, |
| * subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be |
| * included in all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| #include <lib/elf.h> |
| #include <assert.h> |
| #include <debug.h> |
| #include <endian.h> |
| #include <err.h> |
| #include <trace.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <arch/ops.h> |
| |
| #define LOCAL_TRACE 0 |
| |
| struct read_hook_memory_args { |
| const uint8_t *ptr; |
| size_t len; |
| }; |
| |
| static ssize_t elf_read_hook_memory(struct elf_handle *handle, void *buf, uint64_t offset, size_t len) |
| { |
| LTRACEF("handle %p, buf %p, offset %lld, len %zu\n", handle, buf, offset, len); |
| |
| struct read_hook_memory_args *args = handle->read_hook_arg; |
| |
| DEBUG_ASSERT(args); |
| DEBUG_ASSERT(buf); |
| DEBUG_ASSERT(handle); |
| DEBUG_ASSERT(handle->open); |
| |
| ssize_t toread = len; |
| if (offset >= args->len) |
| toread = 0; |
| if (offset + len >= args->len) |
| toread = args->len - offset; |
| |
| memcpy(buf, args->ptr + offset, toread); |
| |
| LTRACEF("returning %ld\n", toread); |
| |
| return toread; |
| } |
| |
| status_t elf_open_handle(elf_handle_t *handle, elf_read_hook_t read_hook, void *read_hook_arg, bool free_read_hook_arg) |
| { |
| if (!handle) |
| return ERR_INVALID_ARGS; |
| if (!read_hook) |
| return ERR_INVALID_ARGS; |
| |
| memset(handle, 0, sizeof(*handle)); |
| |
| handle->read_hook = read_hook; |
| handle->read_hook_arg = read_hook_arg; |
| handle->free_read_hook_arg = free_read_hook_arg; |
| |
| handle->open = true; |
| |
| return NO_ERROR; |
| } |
| |
| status_t elf_open_handle_memory(elf_handle_t *handle, const void *ptr, size_t len) |
| { |
| struct read_hook_memory_args *args = malloc(sizeof(struct read_hook_memory_args)); |
| |
| args->ptr = ptr; |
| args->len = len; |
| |
| status_t err = elf_open_handle(handle, elf_read_hook_memory, (void *)args, true); |
| if (err < 0) |
| free(args); |
| |
| return err; |
| } |
| |
| void elf_close_handle(elf_handle_t *handle) |
| { |
| if (!handle || !handle->open) |
| return; |
| |
| handle->open = false; |
| |
| if (handle->free_read_hook_arg) |
| free(handle->read_hook_arg); |
| |
| free(handle->pheaders); |
| } |
| |
| static int verify_eheader(const struct Elf32_Ehdr *eheader) |
| { |
| if (memcmp(eheader->e_ident, ELF_MAGIC, 4) != 0) |
| return ERR_NOT_FOUND; |
| |
| if (eheader->e_ident[EI_CLASS] != ELFCLASS32) |
| return ERR_NOT_FOUND; |
| |
| #if BYTE_ORDER == LITTLE_ENDIAN |
| if (eheader->e_ident[EI_DATA] != ELFDATA2LSB) |
| return ERR_NOT_FOUND; |
| #elif BYTE_ORDER == BIG_ENDIAN |
| if (eheader->e_ident[EI_DATA] != ELFDATA2MSB) |
| return ERR_NOT_FOUND; |
| #endif |
| |
| if (eheader->e_ident[EI_VERSION] != EV_CURRENT) |
| return ERR_NOT_FOUND; |
| |
| if (eheader->e_phoff == 0) |
| return ERR_NOT_FOUND; |
| |
| if (eheader->e_phentsize < sizeof(struct Elf32_Phdr)) |
| return ERR_NOT_FOUND; |
| |
| #if ARCH_ARM |
| if (eheader->e_machine != EM_ARM) |
| return ERR_NOT_FOUND; |
| #elif ARCH_X86 |
| if (eheader->e_machine != EM_386) |
| return ERR_NOT_FOUND; |
| #elif ARCH_X86_64 |
| if (eheader->e_machine != EM_X86_64) |
| return ERR_NOT_FOUND; |
| #elif ARCH_ARM64 |
| if (eheader->e_machine != EM_AARCH64) |
| return ERR_NOT_FOUND; |
| #elif ARCH_MICROBLAZE |
| if (eheader->e_machine != EM_MICROBLAZE) |
| return ERR_NOT_FOUND; |
| #else |
| #error find proper EM_ define for your machine |
| #endif |
| |
| return NO_ERROR; |
| } |
| |
| status_t elf_load(elf_handle_t *handle) |
| { |
| if (!handle) |
| return ERR_INVALID_ARGS; |
| if (!handle->open) |
| return ERR_NOT_READY; |
| |
| // validate that this is an ELF file |
| ssize_t readerr = handle->read_hook(handle, &handle->eheader, 0, sizeof(handle->eheader)); |
| if (readerr < (ssize_t)sizeof(handle->eheader)) { |
| LTRACEF("couldn't read elf header\n"); |
| return ERR_NOT_FOUND; |
| } |
| |
| if (verify_eheader(&handle->eheader)) { |
| LTRACEF("header not valid\n"); |
| return ERR_NOT_FOUND; |
| } |
| |
| // sanity check number of program headers |
| LTRACEF("number of program headers %u, entry size %u\n", handle->eheader.e_phnum, handle->eheader.e_phentsize); |
| if (handle->eheader.e_phnum > 16 || handle->eheader.e_phentsize != sizeof(struct Elf32_Phdr)) { |
| LTRACEF("too many program headers or bad size\n"); |
| return ERR_NO_MEMORY; |
| } |
| |
| // allocate and read in the program headers |
| handle->pheaders = calloc(1, handle->eheader.e_phnum * handle->eheader.e_phentsize); |
| if (!handle->pheaders) { |
| LTRACEF("failed to allocate memory for program headers\n"); |
| return ERR_NO_MEMORY; |
| } |
| |
| readerr = handle->read_hook(handle, handle->pheaders, handle->eheader.e_phoff, handle->eheader.e_phnum * handle->eheader.e_phentsize); |
| if (readerr < (ssize_t)(handle->eheader.e_phnum * handle->eheader.e_phentsize)) { |
| LTRACEF("failed to read program headers\n"); |
| return ERR_NO_MEMORY; |
| } |
| |
| LTRACEF("program headers:\n"); |
| uint load_count = 0; |
| for (uint i = 0; i < handle->eheader.e_phnum; i++) { |
| // parse the program headers |
| struct Elf32_Phdr *pheader = &handle->pheaders[i]; |
| |
| LTRACEF("%u: type %u offset 0x%x vaddr 0x%x paddr 0x%x memsiz %u filesize %u\n", |
| i, pheader->p_type, pheader->p_offset, pheader->p_vaddr, pheader->p_paddr, pheader->p_memsz, pheader->p_filesz); |
| |
| // we only care about PT_LOAD segments at the moment |
| if (pheader->p_type == PT_LOAD) { |
| // if the memory allocation hook exists, call it |
| void *ptr = (void *)(uintptr_t)pheader->p_vaddr; |
| |
| if (handle->mem_alloc_hook) { |
| status_t err = handle->mem_alloc_hook(handle, &ptr, pheader->p_memsz, load_count, 0); |
| if (err < 0) { |
| LTRACEF("mem hook failed, abort\n"); |
| // XXX clean up what we got so far |
| return err; |
| } |
| } |
| |
| // read the file portion of the segment into memory at vaddr |
| LTRACEF("reading segment at offset %u to address %p\n", pheader->p_offset, ptr); |
| readerr = handle->read_hook(handle, ptr, pheader->p_offset, pheader->p_filesz); |
| if (readerr < (ssize_t)pheader->p_filesz) { |
| LTRACEF("error %ld reading program header %u\n", readerr, i); |
| return (readerr < 0) ? readerr : ERR_IO; |
| } |
| |
| // zero out he difference between memsz and filesz |
| size_t tozero = pheader->p_memsz - pheader->p_filesz; |
| if (tozero > 0) { |
| uint8_t *ptr2 = (uint8_t *)ptr + pheader->p_filesz; |
| LTRACEF("zeroing memory at %p, size %zu\n", ptr2, tozero); |
| memset(ptr2, 0, tozero); |
| } |
| |
| // make sure the i&d cache are coherent, if they exist |
| arch_sync_cache_range((addr_t)ptr, pheader->p_memsz); |
| |
| // track the number of load segments we have seen to pass the mem alloc hook |
| load_count++; |
| } |
| } |
| |
| // save the entry point |
| handle->entry = handle->eheader.e_entry; |
| |
| return NO_ERROR; |
| } |
| |