linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Deliver z/VM CP special messages (SMSG) as uevents.

 *

 * The driver registers for z/VM CP special messages with the

 * "APP" prefix. Incoming messages are delivered to user space

 * as uevents.

 *

 * Copyright IBM Corp. 2010

 * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>

 *

 */

#define KMSG_COMPONENT      "smsgiucv_app"

#define pr_fmt(fmt)     KMSG_COMPONENT ": " fmt

​

#include <linux/ctype.h>

#include <linux/err.h>

#include <linux/device.h>

#include <linux/list.h>

#include <linux/kobject.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/workqueue.h>

#include <net/iucv/iucv.h>

#include "smsgiucv.h"

​

/* prefix used for SMSG registration */

#define SMSG_PREFIX     "APP"

​

/* SMSG related uevent environment variables */

#define ENV_SENDER_STR      "SMSG_SENDER="

#define ENV_SENDER_LEN      (strlen(ENV_SENDER_STR) + 8 + 1)

#define ENV_PREFIX_STR      "SMSG_ID="

#define ENV_PREFIX_LEN      (strlen(ENV_PREFIX_STR) + \

                 strlen(SMSG_PREFIX) + 1)

#define ENV_TEXT_STR        "SMSG_TEXT="

#define ENV_TEXT_LEN(msg)   (strlen(ENV_TEXT_STR) + strlen((msg)) + 1)

​

/* z/VM user ID which is permitted to send SMSGs

 * If the value is undefined or empty (""), special messages are

 * accepted from any z/VM user ID. */

static char *sender;

module_param(sender, charp, 0400);

MODULE_PARM_DESC(sender, "z/VM user ID from which CP SMSGs are accepted");

​

/* SMSG device representation */

static struct device *smsg_app_dev;

​

/* list element for queuing received messages for delivery */

struct smsg_app_event {

    struct list_head list;

    char *buf;

    char *envp[4];

};

​

/* queue for outgoing uevents */

static LIST_HEAD(smsg_event_queue);

static DEFINE_SPINLOCK(smsg_event_queue_lock);

​

static void smsg_app_event_free(struct smsg_app_event *ev)

{

    kfree(ev->buf);

    kfree(ev);

}

​

static struct smsg_app_event *smsg_app_event_alloc(const char *from,

                           const char *msg)

{

    struct smsg_app_event *ev;

​

    ev = kzalloc(sizeof(*ev), GFP_ATOMIC);

    if (!ev)

        return NULL;

​

    ev->buf = kzalloc(ENV_SENDER_LEN + ENV_PREFIX_LEN +

              ENV_TEXT_LEN(msg), GFP_ATOMIC);

    if (!ev->buf) {

        kfree(ev);

        return NULL;

    }

​

    /* setting up environment pointers into buf */

    ev->envp[0] = ev->buf;

    ev->envp[1] = ev->envp[0] + ENV_SENDER_LEN;

    ev->envp[2] = ev->envp[1] + ENV_PREFIX_LEN;

    ev->envp[3] = NULL;

​

    /* setting up environment: sender, prefix name, and message text */

    snprintf(ev->envp[0], ENV_SENDER_LEN, ENV_SENDER_STR "%s", from);

    snprintf(ev->envp[1], ENV_PREFIX_LEN, ENV_PREFIX_STR "%s", SMSG_PREFIX);

    snprintf(ev->envp[2], ENV_TEXT_LEN(msg), ENV_TEXT_STR "%s", msg);