From ca9093b327311b17a6c77820abb0c66abf6a94f4 Mon Sep 17 00:00:00 2001 From: sobomax Date: Mon, 2 Oct 2000 14:14:07 +0000 Subject: 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 --- share/examples/kld/cdev/README | 15 ++++++++++ share/examples/kld/cdev/module/Makefile | 4 +-- share/examples/kld/cdev/module/cdev.c | 50 ++++++++++++++++++++++++++++++++ share/examples/kld/cdev/module/cdev.h | 10 +++++-- share/examples/kld/cdev/module/cdevmod.c | 22 +++++++++----- share/examples/kld/cdev/test/Makefile | 2 +- share/examples/kld/cdev/test/testcdev.c | 26 ++++++++++++++++- 7 files changed, 114 insertions(+), 15 deletions(-) (limited to 'share/examples/kld/cdev') diff --git a/share/examples/kld/cdev/README b/share/examples/kld/cdev/README index 2f1114c..dc650f1 100644 --- a/share/examples/kld/cdev/README +++ b/share/examples/kld/cdev/README @@ -58,6 +58,8 @@ # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF # SUCH DAMAGE. # +# $FreeBSD$ +# 1.0 Overview @@ -83,6 +85,19 @@ try out changes to kernel code without rebuilding and booting from the new kernel. + The idea behind this example is to show some interaction + with the device driver. Therefore the flow of the code that + this driver is aimed at is as follows: + + open(2) -> ioctl(2) -> write(2) -> read(2) -> close(2). + + We will first open the device in the /dev/ directory; then + we will send an ioctl message to it using ioctl(2) call; + then write a small string via the write(2) call. This string + we write to the device will be stored in a static buffer, + and later will be accessible via the read(2) call. Finally, + we will close(2) our open()'d device so that we may no + longer make read or write calls on it. 2.0 Directions diff --git a/share/examples/kld/cdev/module/Makefile b/share/examples/kld/cdev/module/Makefile index 8fedcfc..50047cc 100644 --- a/share/examples/kld/cdev/module/Makefile +++ b/share/examples/kld/cdev/module/Makefile @@ -78,8 +78,8 @@ KLDUNLOAD = /sbin/kldunload CLEANFILES+= ${KMOD} -load: /dev/cdev - ${KLDLOAD} -v ./${KMOD} +load: /dev/cdev ${KMOD}.ko + ${KLDLOAD} -v ./${KMOD}.ko unload: rm -f /dev/cdev diff --git a/share/examples/kld/cdev/module/cdev.c b/share/examples/kld/cdev/module/cdev.c index 4cbbc07..ba6fa54 100644 --- a/share/examples/kld/cdev/module/cdev.c +++ b/share/examples/kld/cdev/module/cdev.c @@ -64,7 +64,11 @@ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * + * + * $FreeBSD$ */ +#include +#include #include #include #include @@ -90,11 +94,17 @@ #define CDEV_IOCTL1 _IOR('C', 1, u_int) +/* Stores string recv'd by _write() */ +static char buf[512+1]; +static int len; + int mydev_open(dev_t dev, int flag, int otyp, struct proc *procp) { printf("mydev_open: dev_t=%d, flag=%x, otyp=%x, procp=%p\n", dev2udev(dev), flag, otyp, procp); + memset(&buf, '\0', 513); + len = 0; return (0); } @@ -125,3 +135,43 @@ mydev_ioctl(dev_t dev, u_long cmd, caddr_t arg, int mode, struct proc *procp) } return error; } + +/* + * mydev_write takes in a character string and saves it + * to buf for later accessing. + */ +int +mydev_write(dev_t dev, struct uio *uio, int ioflag) +{ + int err = 0; + + printf("mydev_write: dev_t=%d, uio=%p, ioflag=%d\n", + dev2udev(dev), uio, ioflag); + + err = copyinstr(uio->uio_iov->iov_base, &buf, 512, &len); + if (err != 0) { + printf("Write to \"cdev\" failed.\n"); + } + return(err); +} + +/* + * The mydev_read function just takes the buf that was saved + * via mydev_write() and returns it to userland for + * accessing. + */ +int +mydev_read(dev_t dev, struct uio *uio, int ioflag) +{ + int err = 0; + + printf("mydev_read: dev_t=%d, uio=%p, ioflag=%d\n", + dev2udev(dev), uio, ioflag); + + if (len <= 0) { + err = -1; + } else { /* copy buf to userland */ + copystr(&buf, uio->uio_iov->iov_base, 513, &len); + } + return(err); +} diff --git a/share/examples/kld/cdev/module/cdev.h b/share/examples/kld/cdev/module/cdev.h index 88b3cb9..b09e53a 100644 --- a/share/examples/kld/cdev/module/cdev.h +++ b/share/examples/kld/cdev/module/cdev.h @@ -65,13 +65,17 @@ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * + * + * $FreeBSD$ */ #ifndef __CDEV_H_ #define __CDEV_H_ -d_open_t mydev_open; -d_close_t mydev_close; -d_ioctl_t mydev_ioctl; +d_open_t mydev_open; +d_close_t mydev_close; +d_ioctl_t mydev_ioctl; +d_read_t mydev_read; +d_write_t mydev_write; #endif diff --git a/share/examples/kld/cdev/module/cdevmod.c b/share/examples/kld/cdev/module/cdevmod.c index 5c9ef47..cb80a72 100644 --- a/share/examples/kld/cdev/module/cdevmod.c +++ b/share/examples/kld/cdev/module/cdevmod.c @@ -64,6 +64,8 @@ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * + * + * $FreeBSD$ */ #include #include @@ -78,25 +80,27 @@ static struct cdevsw my_devsw = { /* open */ mydev_open, /* close */ mydev_close, - /* read */ noread, - /* write */ nowrite, + /* read */ mydev_read, + /* write */ mydev_write, /* ioctl */ mydev_ioctl, - /* stop */ nostop, - /* reset */ noreset, - /* devtotty */ nodevtotty, /* poll */ nopoll, /* mmap */ nommap, /* strategy */ nostrategy, /* name */ "cdev", - /* parms */ noparms, /* maj */ CDEV_MAJOR, /* dump */ nodump, /* psize */ nopsize, /* flags */ D_TTY, - /* maxio */ 0, /* bmaj */ -1 }; +/* + * Used as the variable that is the reference to our device + * in devfs... we must keep this variable sane until we + * call kldunload. + */ +static dev_t sdev; + /* * This function is called each time the module is loaded or unloaded. * Since we are a miscellaneous module, we have to provide whatever @@ -123,10 +127,12 @@ cdev_load(module_t mod, int cmd, void *arg) printf("Copyright (c) 1998\n"); printf("Rajesh Vaidheeswarran\n"); printf("All rights reserved\n"); + sdev = make_dev(&my_devsw, 0, UID_ROOT, GID_WHEEL, 0600, "cdev"); break; /* Success*/ case MOD_UNLOAD: printf("Unloaded kld character device driver\n"); + destroy_dev(sdev); break; /* Success*/ default: /* we only understand load/unload*/ @@ -139,4 +145,4 @@ cdev_load(module_t mod, int cmd, void *arg) /* Now declare the module to the system */ -DEV_MODULE(cdev, CDEV_MAJOR, -1, my_devsw, cdev_load, 0); +DEV_MODULE(cdev, cdev_load, NULL); 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 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 #include +#include #include #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); } -- cgit v1.1