cregit-Linux how code gets into the kernel

Release 4.11 drivers/s390/net/smsgiucv_app.c

Directory: drivers/s390/net
/*
 * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Hendrik Brueckner23100.00%1100.00%
Total23100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Hendrik Brueckner190100.00%1100.00%
Total190100.00%1100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Hendrik Brueckner107100.00%1100.00%
Total107100.00%1100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Hendrik Brueckner119100.00%1100.00%
Total119100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Hendrik Brueckner21698.18%266.67%
Alan Stern41.82%133.33%
Total220100.00%3100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Hendrik Brueckner35100.00%1100.00%
Total35100.00%1100.00%

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>");

Overall Contributors

PersonTokensPropCommitsCommitProp
Hendrik Brueckner86199.19%250.00%
Alan Stern40.46%125.00%
Tejun Heo30.35%125.00%
Total868100.00%4100.00%
Directory: drivers/s390/net
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