1 files changed, 212 insertions, 0 deletions

diff --git a/drivers/s390/net/smsgiucv_app.c b/drivers/s390/net/smsgiucv_app.c
new file mode 100644
index 000000000000..137688790207
--- /dev/null
+++ b/drivers/s390/net/smsgiucv_app.c
@@ -0,0 +1,212 @@
+/*
+ * 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);
+
+        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>");