Function elf_file_mmap

components/lwp/lwp_elf.c:619–701

* @brief Map ELF segments into memory. * * This function maps the loadable segments of an ELF file into the process's address space. * It handles both executable and shared library files, manages BSS sections, and sets up * the load address and base address for dynamic libraries. * * @param load_info Pointer to the structure containing ELF loading context. * @param elf_info Pointer to the s

 * @return -ENOMEM if memory allocation fails.
 */
static int elf_file_mmap(elf_load_info_t *load_info, elf_info_t *elf_info, rt_ubase_t *elfload_addr,
    rt_uint32_t map_size, rt_ubase_t *load_base)
{
    int ret, i;
    rt_ubase_t map_va, bss_start, bss_end;
    Elf_Ehdr *ehdr = &elf_info->ehdr; /* ELF header */
    Elf_Phdr *phdr = elf_info->phdr;  /* Program header array */
    const Elf_Phdr *tmp_phdr = phdr;  /* Current program header */
    int fd = elf_info->fd; /* File descriptor for ELF file */
    rt_ubase_t load_addr;  /* Calculated load address */
    size_t prot = PROT_READ | PROT_WRITE; /* Memory protection flags */
    size_t flags = MAP_FIXED | MAP_PRIVATE; /* Memory mapping flags */

    /* Iterate through all program headers */
    for (i = 0; i < ehdr->e_phnum; ++i, ++tmp_phdr)
    {
        /* Only process PT_LOAD segments (loadable segments) */
        if (tmp_phdr->p_type != PT_LOAD)
        {
            continue;
        }

        /* For executable files, validate the program header */
        if (ehdr->e_type == ET_EXEC)
        {
            if (elf_check_phdr(tmp_phdr) != RT_EOK)
            {
                LOG_E("%s : elf_check_phdr failed", __func__);
                return -RT_ERROR;
            }
        }

        load_addr = tmp_phdr->p_vaddr + *load_base;
        LOG_D("%s : p_vaddr : 0x%x, load_addr : 0x%x", __func__, tmp_phdr->p_vaddr, load_addr);

        /* When both the segment's virtual address and the load base are 0, the segment is loaded at any available
         address rather than a fixed one. This behavior is particularly useful for Position-Independent Code (PIC)
         or shared libraries. */
        if ((tmp_phdr->p_vaddr == 0) && (*load_base == 0))
        {
            flags &= ~MAP_FIXED;
        }

        /* Map the segment into memory */
        map_va = elf_map(load_info->lwp, tmp_phdr, fd, load_addr, prot, flags, map_size);
        if (!map_va)
        {
            LOG_E("%s : elf_map failed", __func__);
            return -ENOMEM;
        }

        map_size = 0;

        elf_user_dump(load_info->lwp, (void *)load_addr, 64);

        /* Handle BSS section (zero-initialized data) */
        if ((tmp_phdr->p_memsz > tmp_phdr->p_filesz) && (tmp_phdr->p_flags & PF_W))
        {