Fix cdev kld example after it has been broken for year or so. Also extend list

of supported operations by example read() and write() operations.

Inspired by:    http://www.daemonnews.org/200010/blueprints.html
PR:             16173
Submitted by:   sobomax

2 files changed, 26 insertions, 2 deletions

diff --git a/share/examples/kld/cdev/test/Makefile b/share/examples/kld/cdev/test/Makefile
index 001fde1..2ca3d21 100644
--- a/share/examples/kld/cdev/test/Makefile
+++ b/share/examples/kld/cdev/test/Makefile
@@ -87,6 +87,6 @@ unload:
 	@echo "has been successfully unloaded by building 'unload' in"
 	@echo "the 'module' subdirectory."
 	@echo
-	${MODSTAT} -n misc_mod
+	${MODSTAT} -n cdev
 
 .include <bsd.prog.mk>
diff --git a/share/examples/kld/cdev/test/testcdev.c b/share/examples/kld/cdev/test/testcdev.c
index e43df97..8f2c0b3 100644
--- a/share/examples/kld/cdev/test/testcdev.c
+++ b/share/examples/kld/cdev/test/testcdev.c
@@ -67,21 +67,28 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
+ *
+ * $FreeBSD$
  */
 #include <stdio.h>
 #include <fcntl.h>
+#include <string.h>
 #include <sys/ioccom.h>
 
 #define CDEV_IOCTL1     _IOR('C', 1, u_int)
 #define CDEV_DEVICE	"cdev"
 
+static char writestr[] = "Hello kernel!";
+static char buf[512+1];
+
 int
 main(int argc, char *argv[])
 {
     int kernel_fd;
     int one;
+    int len;
 
-    if ((kernel_fd = open("/dev/" CDEV_DEVICE, O_RDONLY)) == -1) {
+    if ((kernel_fd = open("/dev/" CDEV_DEVICE, O_RDWR)) == -1) {
 	perror("/dev/" CDEV_DEVICE);
 	exit(1);
     }
@@ -92,5 +99,22 @@ main(int argc, char *argv[])
     } else {
 	printf( "Sent ioctl CDEV_IOCTL1 to device /dev/" CDEV_DEVICE "\n");
     }
+
+    len = strlen(writestr) + 1;
+
+    /* Write operation */
+    if (write(kernel_fd, writestr, len) == -1) {
+	perror("write()");
+    } else {
+	printf("Written \"%s\" string to device /dev/" CDEV_DEVICE "\n", writestr);
+    }
+
+    /* Read operation */
+    if (read(kernel_fd, buf, len) == -1) {
+	perror("read()");
+    } else {
+	printf("Read \"%s\" string from device /dev/" CDEV_DEVICE "\n", buf);
+    }
+
     exit(0);
 }