smsgiucv.c

Go to the documentation of this file.

/*
 * IUCV special message driver
 *
 * Copyright IBM Corp. 2003, 2009
 *
 * Author(s): Martin Schwidefsky ([email protected])
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <net/iucv/iucv.h>
#include <asm/cpcmd.h>
#include <asm/ebcdic.h>
#include "smsgiucv.h"

struct smsg_callback {
    struct list_head list;
    const char *prefix;
    int len;
    void (*callback)(const char *from, char *str);
};

MODULE_AUTHOR
   ("(C) 2003 IBM Corporation by Martin Schwidefsky ([email protected])");
MODULE_DESCRIPTION ("Linux for S/390 IUCV special message driver");

static struct iucv_path *smsg_path;
/* dummy device used as trigger for PM functions */
static struct device *smsg_dev;

static DEFINE_SPINLOCK(smsg_list_lock);
static LIST_HEAD(smsg_list);
static int iucv_path_connected;

static int smsg_path_pending(struct iucv_path *, u8 ipvmid[8], u8 ipuser[16]);
static void smsg_message_pending(struct iucv_path *, struct iucv_message *);

static struct iucv_handler smsg_handler = {
    .path_pending    = smsg_path_pending,
    .message_pending = smsg_message_pending,
};

static int smsg_path_pending(struct iucv_path *path, u8 ipvmid[8],
                 u8 ipuser[16])
{
    if (strncmp(ipvmid, "*MSG    ", 8) != 0)
        return -EINVAL;
    /* Path pending from *MSG. */
    return iucv_path_accept(path, &smsg_handler, "SMSGIUCV        ", NULL);
}

static void smsg_message_pending(struct iucv_path *path,
                 struct iucv_message *msg)
{
    struct smsg_callback *cb;
    unsigned char *buffer;
    unsigned char sender[9];
    int rc, i;

    buffer = kmalloc(msg->length + 1, GFP_ATOMIC | GFP_DMA);
    if (!buffer) {
        iucv_message_reject(path, msg);
        return;
    }
    rc = iucv_message_receive(path, msg, 0, buffer, msg->length, NULL);
    if (rc == 0) {
        buffer[msg->length] = 0;
        EBCASC(buffer, msg->length);
        memcpy(sender, buffer, 8);
        sender[8] = 0;
        /* Remove trailing whitespace from the sender name. */
        for (i = 7; i >= 0; i--) {
            if (sender[i] != ' ' && sender[i] != '\t')
                break;
            sender[i] = 0;
        }
        spin_lock(&smsg_list_lock);
        list_for_each_entry(cb, &smsg_list, list)
            if (strncmp(buffer + 8, cb->prefix, cb->len) == 0) {
                cb->callback(sender, buffer + 8);
                break;
            }
        spin_unlock(&smsg_list_lock);
    }
    kfree(buffer);
}

int smsg_register_callback(const char *prefix,
               void (*callback)(const char *from, char *str))
{
    struct smsg_callback *cb;

    cb = kmalloc(sizeof(struct smsg_callback), GFP_KERNEL);
    if (!cb)
        return -ENOMEM;
    cb->prefix = prefix;
    cb->len = strlen(prefix);
    cb->callback = callback;
    spin_lock_bh(&smsg_list_lock);
    list_add_tail(&cb->list, &smsg_list);
    spin_unlock_bh(&smsg_list_lock);
    return 0;
}

void smsg_unregister_callback(const char *prefix,
                  void (*callback)(const char *from,
                           char *str))
{
    struct smsg_callback *cb, *tmp;

    spin_lock_bh(&smsg_list_lock);
    cb = NULL;
    list_for_each_entry(tmp, &smsg_list, list)
        if (tmp->callback == callback &&
            strcmp(tmp->prefix, prefix) == 0) {
            cb = tmp;
            list_del(&cb->list);
            break;
        }
    spin_unlock_bh(&smsg_list_lock);
    kfree(cb);
}

static int smsg_pm_freeze(struct device *dev)
{
#ifdef CONFIG_PM_DEBUG
    printk(KERN_WARNING "smsg_pm_freeze\n");
#endif
    if (smsg_path && iucv_path_connected) {
        iucv_path_sever(smsg_path, NULL);
        iucv_path_connected = 0;
    }
    return 0;
}

static int smsg_pm_restore_thaw(struct device *dev)
{
    int rc;

#ifdef CONFIG_PM_DEBUG
    printk(KERN_WARNING "smsg_pm_restore_thaw\n");
#endif
    if (smsg_path && !iucv_path_connected) {
        memset(smsg_path, 0, sizeof(*smsg_path));
        smsg_path->msglim = 255;
        smsg_path->flags = 0;
        rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
                       NULL, NULL, NULL);
#ifdef CONFIG_PM_DEBUG
        if (rc)
            printk(KERN_ERR
                   "iucv_path_connect returned with rc %i\n", rc);
#endif
        if (!rc)
            iucv_path_connected = 1;
        cpcmd("SET SMSG IUCV", NULL, 0, NULL);
    }
    return 0;
}

static const struct dev_pm_ops smsg_pm_ops = {
    .freeze = smsg_pm_freeze,
    .thaw = smsg_pm_restore_thaw,
    .restore = smsg_pm_restore_thaw,
};

static struct device_driver smsg_driver = {
    .owner = THIS_MODULE,
    .name = SMSGIUCV_DRV_NAME,
    .bus  = &iucv_bus,
    .pm = &smsg_pm_ops,
};

static void __exit smsg_exit(void)
{
    cpcmd("SET SMSG IUCV", NULL, 0, NULL);
    device_unregister(smsg_dev);
    iucv_unregister(&smsg_handler, 1);
    driver_unregister(&smsg_driver);
}

static int __init smsg_init(void)
{
    int rc;

    if (!MACHINE_IS_VM) {
        rc = -EPROTONOSUPPORT;
        goto out;
    }
    rc = driver_register(&smsg_driver);
    if (rc != 0)
        goto out;
    rc = iucv_register(&smsg_handler, 1);
    if (rc)
        goto out_driver;
    smsg_path = iucv_path_alloc(255, 0, GFP_KERNEL);
    if (!smsg_path) {
        rc = -ENOMEM;
        goto out_register;
    }
    rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
                   NULL, NULL, NULL);
    if (rc)
        goto out_free_path;
    else
        iucv_path_connected = 1;
    smsg_dev = kzalloc(sizeof(struct device), GFP_KERNEL);
    if (!smsg_dev) {
        rc = -ENOMEM;
        goto out_free_path;
    }
    dev_set_name(smsg_dev, "smsg_iucv");
    smsg_dev->bus = &iucv_bus;
    smsg_dev->parent = iucv_root;
    smsg_dev->release = (void (*)(struct device *))kfree;
    smsg_dev->driver = &smsg_driver;
    rc = device_register(smsg_dev);
    if (rc)
        goto out_put;

    cpcmd("SET SMSG IUCV", NULL, 0, NULL);
    return 0;

out_put:
    put_device(smsg_dev);
out_free_path:
    iucv_path_free(smsg_path);
    smsg_path = NULL;
out_register:
    iucv_unregister(&smsg_handler, 1);
out_driver:
    driver_unregister(&smsg_driver);
out:
    return rc;
}

module_init(smsg_init);
module_exit(smsg_exit);
MODULE_LICENSE("GPL");

EXPORT_SYMBOL(smsg_register_callback);
EXPORT_SYMBOL(smsg_unregister_callback);