diff options
Diffstat (limited to 'drivers/s390/net/smsgiucv_app.c')
| -rw-r--r-- | drivers/s390/net/smsgiucv_app.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/drivers/s390/net/smsgiucv_app.c b/drivers/s390/net/smsgiucv_app.c new file mode 100644 index 000000000..0a263999f --- /dev/null +++ b/drivers/s390/net/smsgiucv_app.c @@ -0,0 +1,219 @@ +// 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); + + 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; + } + 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; + } + + /* convert sender to uppercase characters */ + if (sender) { + int len = strlen(sender); + while (len--) + sender[len] = toupper(sender[len]); + } + + /* register with the smsgiucv device driver */ + rc = smsg_register_callback(SMSG_PREFIX, smsg_app_callback); + if (rc) { + device_unregister(smsg_app_dev); + goto fail; + } + + rc = 0; +fail: + 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>"); |