212 lines
5.3 KiB
C
212 lines
5.3 KiB
C
![]() |
/*
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* Deliver z/VM CP special messages (SMSG) as uevents.
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*
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* The driver registers for z/VM CP special messages with the
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* "APP" prefix. Incoming messages are delivered to user space
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* as uevents.
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*
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* Copyright IBM Corp. 2010
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* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
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*
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*/
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#define KMSG_COMPONENT "smsgiucv_app"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/ctype.h>
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/list.h>
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#include <linux/kobject.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/workqueue.h>
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#include <net/iucv/iucv.h>
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#include "smsgiucv.h"
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/* prefix used for SMSG registration */
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#define SMSG_PREFIX "APP"
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/* SMSG related uevent environment variables */
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#define ENV_SENDER_STR "SMSG_SENDER="
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#define ENV_SENDER_LEN (strlen(ENV_SENDER_STR) + 8 + 1)
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#define ENV_PREFIX_STR "SMSG_ID="
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#define ENV_PREFIX_LEN (strlen(ENV_PREFIX_STR) + \
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strlen(SMSG_PREFIX) + 1)
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#define ENV_TEXT_STR "SMSG_TEXT="
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#define ENV_TEXT_LEN(msg) (strlen(ENV_TEXT_STR) + strlen((msg)) + 1)
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/* z/VM user ID which is permitted to send SMSGs
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* If the value is undefined or empty (""), special messages are
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* accepted from any z/VM user ID. */
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static char *sender;
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module_param(sender, charp, 0400);
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MODULE_PARM_DESC(sender, "z/VM user ID from which CP SMSGs are accepted");
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/* SMSG device representation */
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static struct device *smsg_app_dev;
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/* list element for queuing received messages for delivery */
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struct smsg_app_event {
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struct list_head list;
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char *buf;
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char *envp[4];
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};
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/* queue for outgoing uevents */
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static LIST_HEAD(smsg_event_queue);
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static DEFINE_SPINLOCK(smsg_event_queue_lock);
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static void smsg_app_event_free(struct smsg_app_event *ev)
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{
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kfree(ev->buf);
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kfree(ev);
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}
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static struct smsg_app_event *smsg_app_event_alloc(const char *from,
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const char *msg)
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{
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struct smsg_app_event *ev;
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ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
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if (!ev)
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return NULL;
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ev->buf = kzalloc(ENV_SENDER_LEN + ENV_PREFIX_LEN +
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ENV_TEXT_LEN(msg), GFP_ATOMIC);
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if (!ev->buf) {
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kfree(ev);
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return NULL;
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}
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/* setting up environment pointers into buf */
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ev->envp[0] = ev->buf;
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ev->envp[1] = ev->envp[0] + ENV_SENDER_LEN;
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ev->envp[2] = ev->envp[1] + ENV_PREFIX_LEN;
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ev->envp[3] = NULL;
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/* setting up environment: sender, prefix name, and message text */
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snprintf(ev->envp[0], ENV_SENDER_LEN, ENV_SENDER_STR "%s", from);
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snprintf(ev->envp[1], ENV_PREFIX_LEN, ENV_PREFIX_STR "%s", SMSG_PREFIX);
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snprintf(ev->envp[2], ENV_TEXT_LEN(msg), ENV_TEXT_STR "%s", msg);
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return ev;
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}
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static void smsg_event_work_fn(struct work_struct *work)
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{
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LIST_HEAD(event_queue);
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struct smsg_app_event *p, *n;
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struct device *dev;
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dev = get_device(smsg_app_dev);
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if (!dev)
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return;
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spin_lock_bh(&smsg_event_queue_lock);
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list_splice_init(&smsg_event_queue, &event_queue);
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spin_unlock_bh(&smsg_event_queue_lock);
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list_for_each_entry_safe(p, n, &event_queue, list) {
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list_del(&p->list);
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kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, p->envp);
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smsg_app_event_free(p);
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}
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put_device(dev);
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}
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static DECLARE_WORK(smsg_event_work, smsg_event_work_fn);
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static void smsg_app_callback(const char *from, char *msg)
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{
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struct smsg_app_event *se;
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/* check if the originating z/VM user ID matches
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* the configured sender. */
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if (sender && strlen(sender) > 0 && strcmp(from, sender) != 0)
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return;
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/* get start of message text (skip prefix and leading blanks) */
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msg += strlen(SMSG_PREFIX);
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while (*msg && isspace(*msg))
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msg++;
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if (*msg == '\0')
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return;
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/* allocate event list element and its environment */
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se = smsg_app_event_alloc(from, msg);
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if (!se)
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return;
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/* queue event and schedule work function */
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spin_lock(&smsg_event_queue_lock);
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list_add_tail(&se->list, &smsg_event_queue);
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spin_unlock(&smsg_event_queue_lock);
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schedule_work(&smsg_event_work);
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return;
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}
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static int __init smsgiucv_app_init(void)
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{
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struct device_driver *smsgiucv_drv;
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int rc;
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if (!MACHINE_IS_VM)
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return -ENODEV;
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smsg_app_dev = kzalloc(sizeof(*smsg_app_dev), GFP_KERNEL);
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if (!smsg_app_dev)
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return -ENOMEM;
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smsgiucv_drv = driver_find(SMSGIUCV_DRV_NAME, &iucv_bus);
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if (!smsgiucv_drv) {
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kfree(smsg_app_dev);
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return -ENODEV;
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}
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rc = dev_set_name(smsg_app_dev, KMSG_COMPONENT);
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if (rc) {
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kfree(smsg_app_dev);
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goto fail_put_driver;
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}
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smsg_app_dev->bus = &iucv_bus;
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smsg_app_dev->parent = iucv_root;
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smsg_app_dev->release = (void (*)(struct device *)) kfree;
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smsg_app_dev->driver = smsgiucv_drv;
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rc = device_register(smsg_app_dev);
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if (rc) {
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put_device(smsg_app_dev);
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goto fail_put_driver;
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}
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/* register with the smsgiucv device driver */
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rc = smsg_register_callback(SMSG_PREFIX, smsg_app_callback);
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if (rc) {
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device_unregister(smsg_app_dev);
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goto fail_put_driver;
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}
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rc = 0;
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fail_put_driver:
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put_driver(smsgiucv_drv);
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return rc;
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}
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module_init(smsgiucv_app_init);
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static void __exit smsgiucv_app_exit(void)
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{
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/* unregister callback */
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smsg_unregister_callback(SMSG_PREFIX, smsg_app_callback);
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/* cancel pending work and flush any queued event work */
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cancel_work_sync(&smsg_event_work);
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smsg_event_work_fn(&smsg_event_work);
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device_unregister(smsg_app_dev);
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}
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module_exit(smsgiucv_app_exit);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("Deliver z/VM CP SMSG as uevents");
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MODULE_AUTHOR("Hendrik Brueckner <brueckner@linux.vnet.ibm.com>");
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