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rt-thread-official/components/libc/posix/libdl/dlelf.c

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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2018/08/29 Bernard first version
* 2021/04/23 chunyexixiaoyu distinguish 32-bit and 64-bit
*/
#include "dlmodule.h"
#include "dlelf.h"
#define DBG_TAG "DLMD"
#define DBG_LVL DBG_INFO
#include <rtdbg.h> // must after of DEBUG_ENABLE or some other options
rt_err_t dlmodule_load_shared_object(struct rt_dlmodule* module, void *module_ptr)
{
rt_bool_t linked = RT_FALSE;
rt_ubase_t index, module_size = 0;
Elf_Addr vstart_addr, vend_addr;
rt_bool_t has_vstart;
RT_ASSERT(module_ptr != RT_NULL);
if (rt_memcmp(elf_module->e_ident, RTMMAG, SELFMAG) == 0)
{
/* rtmlinker finished */
linked = RT_TRUE;
}
/* get the ELF image size */
has_vstart = RT_FALSE;
vstart_addr = vend_addr = RT_NULL;
for (index = 0; index < elf_module->e_phnum; index++)
{
if (phdr[index].p_type != PT_LOAD)
continue;
LOG_D("LOAD segment: %d, 0x%p, 0x%08x", index, phdr[index].p_vaddr, phdr[index].p_memsz);
if (phdr[index].p_memsz < phdr[index].p_filesz)
{
rt_kprintf("invalid elf: segment %d: p_memsz: %d, p_filesz: %d\n",
index, phdr[index].p_memsz, phdr[index].p_filesz);
return RT_NULL;
}
if (!has_vstart)
{
vstart_addr = phdr[index].p_vaddr;
vend_addr = phdr[index].p_vaddr + phdr[index].p_memsz;
has_vstart = RT_TRUE;
if (vend_addr < vstart_addr)
{
LOG_E("invalid elf: segment %d: p_vaddr: %d, p_memsz: %d\n",
index, phdr[index].p_vaddr, phdr[index].p_memsz);
return RT_NULL;
}
}
else
{
if (phdr[index].p_vaddr < vend_addr)
{
LOG_E("invalid elf: segment should be sorted and not overlapped\n");
return RT_NULL;
}
if (phdr[index].p_vaddr > vend_addr + 16)
{
/* There should not be too much padding in the object files. */
LOG_W("warning: too much padding before segment %d", index);
}
vend_addr = phdr[index].p_vaddr + phdr[index].p_memsz;
if (vend_addr < phdr[index].p_vaddr)
{
LOG_E("invalid elf: "
"segment %d address overflow\n", index);
return RT_NULL;
}
}
}
module_size = vend_addr - vstart_addr;
LOG_D("module size: %d, vstart_addr: 0x%p", module_size, vstart_addr);
if (module_size == 0)
{
LOG_E("Module: size error\n");
return -RT_ERROR;
}
module->vstart_addr = vstart_addr;
module->nref = 0;
/* allocate module space */
module->mem_space = rt_malloc(module_size);
if (module->mem_space == RT_NULL)
{
LOG_E("Module: allocate space failed.\n");
return -RT_ERROR;
}
module->mem_size = module_size;
/* zero all space */
rt_memset(module->mem_space, 0, module_size);
for (index = 0; index < elf_module->e_phnum; index++)
{
if (phdr[index].p_type == PT_LOAD)
{
rt_memcpy(module->mem_space + phdr[index].p_vaddr - vstart_addr,
(rt_uint8_t *)elf_module + phdr[index].p_offset,
phdr[index].p_filesz);
}
}
/* set module entry */
module->entry_addr = module->mem_space + elf_module->e_entry - vstart_addr;
/* handle relocation section */
for (index = 0; index < elf_module->e_shnum; index ++)
{
rt_ubase_t i, nr_reloc;
Elf_Sym *symtab;
Elf_Rel *rel;
rt_uint8_t *strtab;
static rt_bool_t unsolved = RT_FALSE;
#if (defined(__arm__) || defined(__i386__) || (__riscv_xlen == 32))
if (!IS_REL(shdr[index]))
continue;
#elif (defined(__aarch64__) || defined(__x86_64__) || (__riscv_xlen == 64))
if (!IS_RELA(shdr[index]))
continue;
#endif
/* get relocate item */
rel = (Elf_Rel *)((rt_uint8_t *)module_ptr + shdr[index].sh_offset);
/* locate .rel.plt and .rel.dyn section */
symtab = (Elf_Sym *)((rt_uint8_t *)module_ptr +
shdr[shdr[index].sh_link].sh_offset);
strtab = (rt_uint8_t *)module_ptr +
shdr[shdr[shdr[index].sh_link].sh_link].sh_offset;
nr_reloc = (rt_ubase_t)(shdr[index].sh_size / sizeof(Elf_Rel));
/* relocate every items */
for (i = 0; i < nr_reloc; i ++)
{
#if (defined(__arm__) || defined(__i386__) || (__riscv_xlen == 32))
Elf_Sym *sym = &symtab[ELF32_R_SYM(rel->r_info)];
#elif (defined(__aarch64__) || defined(__x86_64__) || (__riscv_xlen == 64))
Elf_Sym *sym = &symtab[ELF64_R_SYM(rel->r_info)];
#endif
LOG_D("relocate symbol %s shndx %d", strtab + sym->st_name, sym->st_shndx);
if ((sym->st_shndx != SHT_NULL) ||(ELF_ST_BIND(sym->st_info) == STB_LOCAL))
{
Elf_Addr addr;
addr = (Elf_Addr)(module->mem_space + sym->st_value - vstart_addr);
dlmodule_relocate(module, rel, addr);
}
else if (!linked)
{
Elf_Addr addr;
LOG_D("relocate symbol: %s", strtab + sym->st_name);
/* need to resolve symbol in kernel symbol table */
addr = dlmodule_symbol_find((const char *)(strtab + sym->st_name));
if (addr == 0)
{
LOG_E("Module: can't find %s in kernel symbol table", strtab + sym->st_name);
unsolved = RT_TRUE;
}
else
{
dlmodule_relocate(module, rel, addr);
}
}
rel ++;
}
if (unsolved)
return -RT_ERROR;
}
/* construct module symbol table */
for (index = 0; index < elf_module->e_shnum; index ++)
{
/* find .dynsym section */
rt_uint8_t *shstrab;
shstrab = (rt_uint8_t *)module_ptr +
shdr[elf_module->e_shstrndx].sh_offset;
if (rt_strcmp((const char *)(shstrab + shdr[index].sh_name), ELF_DYNSYM) == 0)
break;
}
/* found .dynsym section */
if (index != elf_module->e_shnum)
{
int i, count = 0;
Elf_Sym *symtab = RT_NULL;
rt_uint8_t *strtab = RT_NULL;
symtab = (Elf_Sym *)((rt_uint8_t *)module_ptr + shdr[index].sh_offset);
strtab = (rt_uint8_t *)module_ptr + shdr[shdr[index].sh_link].sh_offset;
for (i = 0; i < shdr[index].sh_size / sizeof(Elf_Sym); i++)
{
if ((ELF_ST_BIND(symtab[i].st_info) == STB_GLOBAL) &&
(ELF_ST_TYPE(symtab[i].st_info) == STT_FUNC))
count ++;
}
module->symtab = (struct rt_module_symtab *)rt_malloc
(count * sizeof(struct rt_module_symtab));
module->nsym = count;
for (i = 0, count = 0; i < shdr[index].sh_size / sizeof(Elf_Sym); i++)
{
rt_size_t length;
if ((ELF_ST_BIND(symtab[i].st_info) != STB_GLOBAL) ||
(ELF_ST_TYPE(symtab[i].st_info) != STT_FUNC))
continue;
length = rt_strlen((const char *)(strtab + symtab[i].st_name)) + 1;
module->symtab[count].addr =
(void *)(module->mem_space + symtab[i].st_value - module->vstart_addr);
module->symtab[count].name = rt_malloc(length);
rt_memset((void *)module->symtab[count].name, 0, length);
rt_memcpy((void *)module->symtab[count].name,
strtab + symtab[i].st_name,
length);
count ++;
}
/* get priority & stack size params*/
rt_uint32_t flag = 0;
rt_uint16_t priority;
rt_uint32_t stacksize;
for (i = 0; i < shdr[index].sh_size / sizeof(Elf_Sym); i++)
{
if (((flag & 0x01) == 0) &&
(rt_strcmp((const char *)(strtab + symtab[i].st_name), "dlmodule_thread_priority") == 0))
{
flag |= 0x01;
priority = *(rt_uint16_t*)(module->mem_space + symtab[i].st_value - module->vstart_addr);
if (priority < RT_THREAD_PRIORITY_MAX)
{
module->priority = priority;
}
}
if (((flag & 0x02) == 0) &&
(rt_strcmp((const char *)(strtab + symtab[i].st_name), "dlmodule_thread_stacksize") == 0))
{
flag |= 0x02;
stacksize = *(rt_uint32_t*)(module->mem_space + symtab[i].st_value - module->vstart_addr);
if ((stacksize < 2048) || (stacksize > 1024 * 32))
{
module->stack_size = stacksize;
}
}
if ((flag & 0x03) == 0x03)
{
break;
}
}
}
return RT_EOK;
}
rt_err_t dlmodule_load_relocated_object(struct rt_dlmodule* module, void *module_ptr)
{
rt_ubase_t index, rodata_addr = 0, bss_addr = 0, data_addr = 0;
rt_ubase_t module_addr = 0, module_size = 0;
rt_uint8_t *ptr, *strtab, *shstrab;
/* get the ELF image size */
for (index = 0; index < elf_module->e_shnum; index ++)
{
/* text */
if (IS_PROG(shdr[index]) && IS_AX(shdr[index]))
{
module_size += shdr[index].sh_size;
module_addr = shdr[index].sh_addr;
}
/* rodata */
if (IS_PROG(shdr[index]) && IS_ALLOC(shdr[index]))
{
module_size += shdr[index].sh_size;
}
/* data */
if (IS_PROG(shdr[index]) && IS_AW(shdr[index]))
{
module_size += shdr[index].sh_size;
}
/* bss */
if (IS_NOPROG(shdr[index]) && IS_AW(shdr[index]))
{
module_size += shdr[index].sh_size;
}
}
/* no text, data and bss on image */
if (module_size == 0) return RT_NULL;
module->vstart_addr = 0;
/* allocate module space */
module->mem_space = rt_malloc(module_size);
if (module->mem_space == RT_NULL)
{
LOG_E("Module: allocate space failed.\n");
return -RT_ERROR;
}
module->mem_size = module_size;
/* zero all space */
ptr = module->mem_space;
rt_memset(ptr, 0, module_size);
/* load text and data section */
for (index = 0; index < elf_module->e_shnum; index ++)
{
/* load text section */
if (IS_PROG(shdr[index]) && IS_AX(shdr[index]))
{
rt_memcpy(ptr,
(rt_uint8_t *)elf_module + shdr[index].sh_offset,
shdr[index].sh_size);
LOG_D("load text 0x%x, size %d", ptr, shdr[index].sh_size);
ptr += shdr[index].sh_size;
}
/* load rodata section */
if (IS_PROG(shdr[index]) && IS_ALLOC(shdr[index]))
{
rt_memcpy(ptr,
(rt_uint8_t *)elf_module + shdr[index].sh_offset,
shdr[index].sh_size);
rodata_addr = (rt_uint32_t)ptr;
LOG_D("load rodata 0x%x, size %d, rodata 0x%x", ptr,
shdr[index].sh_size, *(rt_uint32_t *)data_addr);
ptr += shdr[index].sh_size;
}
/* load data section */
if (IS_PROG(shdr[index]) && IS_AW(shdr[index]))
{
rt_memcpy(ptr,
(rt_uint8_t *)elf_module + shdr[index].sh_offset,
shdr[index].sh_size);
data_addr = (rt_uint32_t)ptr;
LOG_D("load data 0x%x, size %d, data 0x%x", ptr,
shdr[index].sh_size, *(rt_uint32_t *)data_addr);
ptr += shdr[index].sh_size;
}
/* load bss section */
if (IS_NOPROG(shdr[index]) && IS_AW(shdr[index]))
{
rt_memset(ptr, 0, shdr[index].sh_size);
bss_addr = (rt_uint32_t)ptr;
LOG_D("load bss 0x%x, size %d", ptr, shdr[index].sh_size);
}
}
/* set module entry */
module->entry_addr = (rt_dlmodule_entry_func_t)((rt_uint8_t *)module->mem_space + elf_module->e_entry - module_addr);
/* handle relocation section */
for (index = 0; index < elf_module->e_shnum; index ++)
{
rt_ubase_t i, nr_reloc;
Elf_Sym *symtab;
Elf_Rel *rel;
#if (defined(__arm__) || defined(__i386__) || (__riscv_xlen == 32))
if (!IS_REL(shdr[index]))
continue;
#elif (defined(__aarch64__) || defined(__x86_64__) || (__riscv_xlen == 64))
if (!IS_RELA(shdr[index]))
continue;
#endif
/* get relocate item */
rel = (Elf_Rel *)((rt_uint8_t *)module_ptr + shdr[index].sh_offset);
/* locate .dynsym and .dynstr */
symtab = (Elf_Sym *)((rt_uint8_t *)module_ptr +
shdr[shdr[index].sh_link].sh_offset);
strtab = (rt_uint8_t *)module_ptr +
shdr[shdr[shdr[index].sh_link].sh_link].sh_offset;
shstrab = (rt_uint8_t *)module_ptr +
shdr[elf_module->e_shstrndx].sh_offset;
nr_reloc = (rt_uint32_t)(shdr[index].sh_size / sizeof(Elf_Rel));
/* relocate every items */
for (i = 0; i < nr_reloc; i ++)
{
#if (defined(__arm__) || defined(__i386__) || (__riscv_xlen == 32))
Elf_Sym *sym = &symtab[ELF32_R_SYM(rel->r_info)];
#elif (defined(__aarch64__) || defined(__x86_64__) || (__riscv_xlen == 64))
Elf_Sym *sym = &symtab[ELF64_R_SYM(rel->r_info)];
#endif
LOG_D("relocate symbol: %s", strtab + sym->st_name);
if (sym->st_shndx != STN_UNDEF)
{
Elf_Addr addr = 0;
if ((ELF_ST_TYPE(sym->st_info) == STT_SECTION) ||
(ELF_ST_TYPE(sym->st_info) == STT_OBJECT))
{
if (rt_strncmp((const char *)(shstrab +
shdr[sym->st_shndx].sh_name), ELF_RODATA, 8) == 0)
{
/* relocate rodata section */
LOG_D("rodata");
addr = (Elf_Addr)(rodata_addr + sym->st_value);
}
else if (rt_strncmp((const char *)
(shstrab + shdr[sym->st_shndx].sh_name), ELF_BSS, 5) == 0)
{
/* relocate bss section */
LOG_D("bss");
addr = (Elf_Addr)bss_addr + sym->st_value;
}
else if (rt_strncmp((const char *)(shstrab + shdr[sym->st_shndx].sh_name),
ELF_DATA, 6) == 0)
{
/* relocate data section */
LOG_D("data");
addr = (Elf_Addr)data_addr + sym->st_value;
}
if (addr != 0) dlmodule_relocate(module, rel, addr);
}
else if (ELF_ST_TYPE(sym->st_info) == STT_FUNC)
{
addr = (Elf_Addr)((rt_uint8_t *) module->mem_space - module_addr + sym->st_value);
/* relocate function */
dlmodule_relocate(module, rel, addr);
}
}
else if (ELF_ST_TYPE(sym->st_info) == STT_FUNC)
{
/* relocate function */
dlmodule_relocate(module, rel,
(Elf_Addr)((rt_uint8_t *)
module->mem_space
- module_addr
+ sym->st_value));
}
else
{
Elf_Addr addr;
if (ELF32_R_TYPE(rel->r_info) != R_ARM_V4BX)
{
LOG_D("relocate symbol: %s", strtab + sym->st_name);
/* need to resolve symbol in kernel symbol table */
addr = dlmodule_symbol_find((const char *)(strtab + sym->st_name));
if (addr != (Elf_Addr)RT_NULL)
{
dlmodule_relocate(module, rel, addr);
LOG_D("symbol addr 0x%x", addr);
}
else
LOG_E("Module: can't find %s in kernel symbol table",
strtab + sym->st_name);
}
else
{
addr = (Elf_Addr)((rt_uint8_t *) module->mem_space - module_addr + sym->st_value);
dlmodule_relocate(module, rel, addr);
}
}
rel ++;
}
}
return RT_EOK;
}
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