Function getBuildId

src/pystack/_pystack/elf_common.cpp:546–581

}

std::string
getBuildId(const std::string& filename)
{
    if (elf_version(EV_CURRENT) == EV_NONE) {
        LOG(ERROR) << "libelf library ELF version too old";
        return "";
    }

    if (!fs::exists(filename)) {
        LOG(DEBUG) << filename << " does not exist";
        return "";
    }

    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 "";
    }
    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 "";
    }

    Elf* the_elf = elf.get();

    const void* build_idp = nullptr;
    ssize_t elf_build_id_len = dwelf_elf_gnu_build_id(the_elf, &build_idp);
    if (elf_build_id_len <= 0) {
        return "";
    }
    return buildIdPtrToString(reinterpret_cast<const unsigned char*>(build_idp), elf_build_id_len);
}

}  // namespace pystack