--- /dev/null
+/*
+ * 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/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);
+
+ return ev;
+}
+
+static void smsg_event_work_fn(struct work_struct *work)
+{
+ LIST_HEAD(event_queue);
+ struct smsg_app_event *p, *n;
+ struct device *dev;
+
+ dev = get_device(smsg_app_dev);
+ if (!dev)
+ return;
+
+ spin_lock_bh(&smsg_event_queue_lock);
+ list_splice_init(&smsg_event_queue, &event_queue);
+ spin_unlock_bh(&smsg_event_queue_lock);
+
+ list_for_each_entry_safe(p, n, &event_queue, list) {
+ list_del(&p->list);
+ kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, p->envp);
+ smsg_app_event_free(p);
+ }
+
+ put_device(dev);
+}
+static DECLARE_WORK(smsg_event_work, smsg_event_work_fn);
+
+static void smsg_app_callback(const char *from, char *msg)
+{
+ struct smsg_app_event *se;
+
+ /* check if the originating z/VM user ID matches
+ * the configured sender. */
+ if (sender && strlen(sender) > 0 && strcmp(from, sender) != 0)
+ return;
+
+ /* get start of message text (skip prefix and leading blanks) */
+ msg += strlen(SMSG_PREFIX);
+ while (*msg && isspace(*msg))
+ msg++;
+ if (*msg == '\0')
+ return;
+
+ /* allocate event list element and its environment */
+ se = smsg_app_event_alloc(from, msg);
+ if (!se)
+ return;
+
+ /* queue event and schedule work function */
+ spin_lock(&smsg_event_queue_lock);
+ list_add_tail(&se->list, &smsg_event_queue);
+ spin_unlock(&smsg_event_queue_lock);
+
+ schedule_work(&smsg_event_work);
+ return;
+}
+
+static int __init smsgiucv_app_init(void)
+{
+ struct device_driver *smsgiucv_drv;
+ int rc;
+
+ if (!MACHINE_IS_VM)
+ return -ENODEV;
+
+ smsg_app_dev = kzalloc(sizeof(*smsg_app_dev), GFP_KERNEL);
+ if (!smsg_app_dev)
+ return -ENOMEM;
+
+ smsgiucv_drv = driver_find(SMSGIUCV_DRV_NAME, &iucv_bus);
+ if (!smsgiucv_drv) {
+ kfree(smsg_app_dev);
+ return -ENODEV;
+ }
+
+ rc = dev_set_name(smsg_app_dev, KMSG_COMPONENT);
+ if (rc) {
+ kfree(smsg_app_dev);
+ goto fail_put_driver;
+ }
+ smsg_app_dev->bus = &iucv_bus;
+ smsg_app_dev->parent = iucv_root;
+ smsg_app_dev->release = (void (*)(struct device *)) kfree;
+ smsg_app_dev->driver = smsgiucv_drv;
+ rc = device_register(smsg_app_dev);
+ if (rc) {
+ put_device(smsg_app_dev);
+ goto fail_put_driver;
+ }
+
+ /* register with the smsgiucv device driver */
+ rc = smsg_register_callback(SMSG_PREFIX, smsg_app_callback);
+ if (rc) {
+ device_unregister(smsg_app_dev);
+ goto fail_put_driver;
+ }
+
+ rc = 0;
+fail_put_driver:
+ put_driver(smsgiucv_drv);
+ return rc;
+}
+module_init(smsgiucv_app_init);
+
+static void __exit smsgiucv_app_exit(void)
+{
+ /* unregister callback */
+ smsg_unregister_callback(SMSG_PREFIX, smsg_app_callback);
+
+ /* cancel pending work and flush any queued event work */
+ cancel_work_sync(&smsg_event_work);
+ smsg_event_work_fn(&smsg_event_work);
+
+ device_unregister(smsg_app_dev);
+}
+module_exit(smsgiucv_app_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Deliver z/VM CP SMSG as uevents");
+MODULE_AUTHOR("Hendrik Brueckner <brueckner@linux.vnet.ibm.com>");
projects / deliverable / linux.git / commitdiff
