X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/d8d001a6664b88b66524989589fcd809de6d3a92..e6dbd781772925dfc07b2facfa0a1350e756ad8f:/lunaix-os/kernel/demos/iotest.c

diff --git a/lunaix-os/kernel/demos/iotest.c b/lunaix-os/kernel/demos/iotest.c
index 0cf7cba..0ebe696 100644
--- a/lunaix-os/kernel/demos/iotest.c
+++ b/lunaix-os/kernel/demos/iotest.c
@@ -6,40 +6,70 @@
 
 LOG_MODULE("IOTEST")
 
+#define STDIN 1
+#define STDOUT 0
+
 void
 _iotest_main()
 {
     char test_sequence[] = "Once upon a time, in a magical land of Equestria. "
                            "There were two regal sisters who ruled together "
                            "and created harmony for all the land.";
+    char read_out[256];
 
-    int fd = open("/dev/sda", 0); // sda 设备 - 硬盘
+    // 切换工作目录至 /dev
+    int errno = chdir("/dev");
+    if (errno) {
+        write(STDOUT, "fail to chdir", 15);
+        return;
+    }
 
-    // tty 设备 - 控制台，使用O_DIRECT打开，即所有IO绕过Lunaix内核的缓存机制
-    int tty = open("/dev/tty", FO_DIRECT);
+    if (getcwd(read_out, sizeof(read_out))) {
+        write(STDOUT, "current working dir: ", 22);
+        write(STDOUT, read_out, 256);
+        write(STDOUT, "\n", 2);
+    }
+
+    // sda 设备 - 硬盘
+    //  sda设备属于容积设备（Volumetric Device），
+    //  Lunaix会尽可能缓存任何对此设备的上层读写，并使用延迟写入策略。（FO_DIRECT可用于屏蔽该功能）
+    int fd = open("./sda", 0);
 
-    if (fd < 0 || tty < 0) {
+    if (fd < 0) {
         kprintf(KERROR "fail to open (%d)\n", geterrno());
         return;
     }
 
     // 移动指针至512字节，在大多数情况下，这是第二个逻辑扇区的起始处
     lseek(fd, 512, FSEEK_SET);
-    write(fd, test_sequence, sizeof(test_sequence));
-    lseek(fd, 521, FSEEK_SET);
+
+    // 总共写入 64 * 136 字节，会产生3个页作为缓存
+    for (size_t i = 0; i < 64; i++) {
+        write(fd, test_sequence, sizeof(test_sequence));
+    }
+
+    // 随机读写测试
+    lseek(fd, 4 * 4096, FSEEK_SET);
     write(fd, test_sequence, sizeof(test_sequence));
 
+    write(STDOUT, "input: ", 8);
+    int size = read(STDIN, read_out, 256);
+
+    write(STDOUT, "your input: ", 13);
+    write(STDOUT, read_out, size);
+    write(fd, read_out, size);
+    write(STDOUT, "\n", 1);
+
     // 读出我们写的内容
-    char read_out[256];
     lseek(fd, 512, FSEEK_SET);
     read(fd, read_out, sizeof(read_out));
 
     // 将读出的内容直接写入tty设备
-    write(tty, read_out, sizeof(read_out));
-    write(tty, "\n", 1);
+    write(STDOUT, read_out, sizeof(read_out));
+    write(STDOUT, "\n", 1);
 
+    // 关闭文件，这同时会将页缓存中的数据下发到底层驱动
     close(fd);
-    close(tty);
 
     kprint_hex(read_out, sizeof(read_out));
 }
\ No newline at end of file