linux-module.c

非常经典的一个分布式系统

#define DEBUG_SUBSYSTEM S_LNET

#include <libcfs/libcfs.h>
#include <libcfs/kp30.h>

#define LNET_MINOR 240

int libcfs_ioctl_getdata(char *buf, char *end, void *arg)
{
        struct libcfs_ioctl_hdr   *hdr;
        struct libcfs_ioctl_data  *data;
        int err;
        ENTRY;

        hdr = (struct libcfs_ioctl_hdr *)buf;
        data = (struct libcfs_ioctl_data *)buf;

        err = copy_from_user(buf, (void *)arg, sizeof(*hdr));
        if (err)
                RETURN(err);

        if (hdr->ioc_version != LIBCFS_IOCTL_VERSION) {
                CERROR("PORTALS: version mismatch kernel vs application\n");
                RETURN(-EINVAL);
        }

        if (hdr->ioc_len + buf >= end) {
                CERROR("PORTALS: user buffer exceeds kernel buffer\n");
                RETURN(-EINVAL);
        }


        if (hdr->ioc_len < sizeof(struct libcfs_ioctl_data)) {
                CERROR("PORTALS: user buffer too small for ioctl\n");
                RETURN(-EINVAL);
        }

        err = copy_from_user(buf, (void *)arg, hdr->ioc_len);
        if (err)
                RETURN(err);

        if (libcfs_ioctl_is_invalid(data)) {
                CERROR("PORTALS: ioctl not correctly formatted\n");
                RETURN(-EINVAL);
        }

        if (data->ioc_inllen1)
                data->ioc_inlbuf1 = &data->ioc_bulk[0];

        if (data->ioc_inllen2)
                data->ioc_inlbuf2 = &data->ioc_bulk[0] +
                        size_round(data->ioc_inllen1);

        RETURN(0);
}

int libcfs_ioctl_popdata(void *arg, void *data, int size)
{
	if (copy_to_user((char *)arg, data, size))
		return -EFAULT;
	return 0;
}

extern struct cfs_psdev_ops          libcfs_psdev_ops;

static int
libcfs_psdev_open(struct inode * inode, struct file * file)
{
	struct libcfs_device_userstate **pdu = NULL;
	int    rc = 0;

	if (!inode)
		return (-EINVAL);
	pdu = (struct libcfs_device_userstate **)&file->private_data;
	if (libcfs_psdev_ops.p_open != NULL)
		rc = libcfs_psdev_ops.p_open(0, (void *)pdu);
	else
		return (-EPERM);
	return rc;
}

/* called when closing /dev/device */
static int
libcfs_psdev_release(struct inode * inode, struct file * file)
{
	struct libcfs_device_userstate *pdu;
	int    rc = 0;

	if (!inode)
		return (-EINVAL);
	pdu = file->private_data;
	if (libcfs_psdev_ops.p_close != NULL)
		rc = libcfs_psdev_ops.p_close(0, (void *)pdu);
	else
		rc = -EPERM;
	return rc;
}

static int
libcfs_ioctl(struct inode *inode, struct file *file,
	     unsigned int cmd, unsigned long arg)
{
	struct cfs_psdev_file	 pfile;
	int    rc = 0;

	if (current->fsuid != 0)
		return -EACCES;

	if ( _IOC_TYPE(cmd) != IOC_LIBCFS_TYPE ||
	     _IOC_NR(cmd) < IOC_LIBCFS_MIN_NR  ||
	     _IOC_NR(cmd) > IOC_LIBCFS_MAX_NR ) {
		CDEBUG(D_IOCTL, "invalid ioctl ( type %d, nr %d, size %d )\n",
		       _IOC_TYPE(cmd), _IOC_NR(cmd), _IOC_SIZE(cmd));
		return (-EINVAL);
	}

	/* Handle platform-dependent IOC requests */
	switch (cmd) {
	case IOC_LIBCFS_PANIC:
		if (!capable (CAP_SYS_BOOT))
			return (-EPERM);
		panic("debugctl-invoked panic");
		return (0);
	case IOC_LIBCFS_MEMHOG:
		if (!capable (CAP_SYS_ADMIN))
			return -EPERM;
		/* go thought */
	}

	pfile.off = 0;
	pfile.private_data = file->private_data;
	if (libcfs_psdev_ops.p_ioctl != NULL)
		rc = libcfs_psdev_ops.p_ioctl(&pfile, cmd, (void *)arg);
	else
		rc = -EPERM;
	return (rc);
}

static struct file_operations libcfs_fops = {
	ioctl:   libcfs_ioctl,
	open:    libcfs_psdev_open,
	release: libcfs_psdev_release
};

cfs_psdev_t libcfs_dev = {
	LNET_MINOR,
	"lnet",
	&libcfs_fops
};