Function copy_file_to_memfd

app/src/main/cpp/utils/shared_memory.cpp:139–187

}

int copy_file_to_memfd(int fd, const char *name) {
    if (!has_memfd_support()) {
        return -ENOSYS;
    }
    struct stat64 fileInfo = {};
    if (fstat64(fd, &fileInfo) < 0) {
        return -errno;
    }
    int64_t length = int64_t(fileInfo.st_size);
    if (length <= 0) {
        return -EINVAL;
    }
    if (length > 64 * 1024 * 1024) {
        return -ENOMEM;
    }
    int64_t originOffset = lseek64(fd, 0, SEEK_CUR);
    if (originOffset < 0) {
        return -errno;
    }
    int memfd = (int) syscall(__NR_memfd_create, name ? name : "none", MFD_CLOEXEC | MFD_ALLOW_SEALING);
    if (memfd == -1) {
        return -errno;
    }
    if (ftruncate(memfd, length) == -1) {
        int orig = errno;
        close(memfd);
        errno = orig;
        return -orig;
    }
    if (lseek(fd, 0, SEEK_SET) < 0) {
        int err = errno;
        close(memfd);
        return -err;
    }
    char buf[4096];
    ssize_t i;
    while ((i = read(fd, buf, 4096)) > 0) {
        write(memfd, buf, i);
    }
    if (i != 0) {
        int err = errno;
        lseek64(fd, originOffset, SEEK_SET);
        close(memfd);
        return -err;
    }
    lseek64(memfd, 0, SEEK_SET);
    lseek64(fd, originOffset, SEEK_SET);
    return memfd;
}