Function getSectionInfo

src/pystack/_pystack/elf_common.cpp:393–482

}

bool
getSectionInfo(const std::string& filename, const std::string& section_name, SectionInfo* result)
{
    if (elf_version(EV_CURRENT) == EV_NONE) {
        LOG(ERROR) << "libelf library ELF version too old";
        return false;
    }

    LOG(DEBUG) << "Trying to locate .PyRuntime data offset from program headers";
    file_unique_ptr file(fopen(filename.c_str(), "r"), fclose);
    if (!file || fileno(file.get()) == -1) {
        LOG(ERROR) << "Cannot open ELF file " << filename << " (" << std::strerror(errno) << ")";
        return false;
    }
    const int fd = fileno(file.get());

    elf_unique_ptr elf = elf_unique_ptr(elf_begin(fd, ELF_C_READ_MMAP, nullptr), elf_end);
    if (!elf) {
        LOG(ERROR) << "Cannot read ELF file " << filename;
        return false;
    }

    Elf* the_elf = elf.get();

    size_t shnum;
    size_t nphdr;
    if (elf_getphdrnum(the_elf, &nphdr) != 0) {
        LOG(ERROR) << "Failed to get program headers";
        return false;
    }

    Dwarf_Addr load_point = 0;
    for (size_t i = 0; i < nphdr; i++) {
        GElf_Phdr phdr;
        if (gelf_getphdr(the_elf, i, &phdr) != &phdr) {
            continue;
        }

        if (phdr.p_type != PT_LOAD) {
            continue;
        }

        load_point = phdr.p_vaddr - phdr.p_vaddr % phdr.p_align;
        LOG(DEBUG) << "Found load point of main Python " << filename << " at " << std::hex
                   << std::showbase << load_point;
        break;
    }

    if (elf_getshdrnum(the_elf, &shnum) < 0) {
        LOG(ERROR) << "Cannot determine the number of sections in the ELF file";
        return false;
    }

    size_t shstrndx;
    if (elf_getshdrstrndx(the_elf, &shstrndx) < 0) {
        LOG(ERROR) << "Cannot get the section string table";
        return false;
    }