22. Romfs

22.1. Overview

This example explains how to use Romfs partition.

22.2. Preparation and usage

  • Create a file named aa.bin inside new directory test/child

  • Usage steps：

    • When downloading, check the Romfs checkbox and specify test directory like shown in Figure 1 below. After flashing, you can use ls command to view the contents of the romfs partition;

The original documentation had an image called imgs/image3.png here, but the file is not publically available. This text is here to prevent a missing image warning.

  • Use the romfs command to perform read and write operations on Romfs. You can see that the data read is consistent with the downloaded file data.

22.3. Operations

  • Opening a file:

fd = aos_open("/romfs/demo.bin", 0);
log_info("fd = %d\r\n", fd);
if (fd < 0) {
    log_error("open error.\r\n");
    return;
}

  • Reading file contents:

len = aos_read(fd, buf, 1);
log_info("len = %d\r\n", len);
log_buf(buf, 1);

  • Seeking：

aos_lseek(fd, 1, SEEK_CUR);
memset(buf, 0, sizeof(buf));
len = aos_read(fd, buf, 1);
log_info("len = %d\r\n", len);
log_buf(buf, 1);

  • Getting the file address and file size:

aos_ioctl(fd, IOCTL_ROMFS_GET_FILEBUF, (long unsigned int)&filebuf);
log_info("filebuf.buf = %p\r\n", filebuf.buf);
log_info("filebuf.bufsize = %lu\r\n", filebuf.bufsize);