// SPDX-License-Identifier: GPL-2.0
/*
* character device driver for reading z/VM system service records
*
*
* Copyright IBM Corp. 2004, 2009
* character device driver for reading z/VM system service records,
* Version 1.0
* Author(s): Xenia Tkatschow <xenia@us.ibm.com>
* Stefan Weinhuber <wein@de.ibm.com>
*
*/
#define KMSG_COMPONENT "vmlogrdr"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/uaccess.h>
#include <asm/cpcmd.h>
#include <asm/debug.h>
#include <asm/ebcdic.h>
#include <net/iucv/iucv.h>
#include <linux/kmod.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/string.h>
MODULE_AUTHOR
("(C) 2004 IBM Corporation by Xenia Tkatschow (xenia@us.ibm.com)\n"
" Stefan Weinhuber (wein@de.ibm.com)");
MODULE_DESCRIPTION ("Character device driver for reading z/VM "
"system service records.");
MODULE_LICENSE("GPL");
/*
* The size of the buffer for iucv data transfer is one page,
* but in addition to the data we read from iucv we also
* place an integer and some characters into that buffer,
* so the maximum size for record data is a little less then
* one page.
*/
#define NET_BUFFER_SIZE (PAGE_SIZE - sizeof(int) - sizeof(FENCE))
/*
* The elements that are concurrently accessed by bottom halves are
* connection_established, iucv_path_severed, local_interrupt_buffer
* and receive_ready. The first three can be protected by
* priv_lock. receive_ready is atomic, so it can be incremented and
* decremented without holding a lock.
* The variable dev_in_use needs to be protected by the lock, since
* it's a flag used by open to make sure that the device is opened only
* by one user at the same time.
*/
struct vmlogrdr_priv_t {
char system_service[8];
char internal_name[8];
char recording_name[8];
struct iucv_path *path;
int connection_established;
int iucv_path_severed;
struct iucv_message local_interrupt_buffer;
atomic_t receive_ready;
int minor_num;
char * buffer;
char * current_position;
int remaining;
ulong residual_length;
int buffer_free;
int dev_in_use; /* 1: already opened, 0: not opened*/
spinlock_t priv_lock;
struct device *device;
struct device *class_device;
int autorecording;
int autopurge;
};
/*
* File operation structure for vmlogrdr devices
*/
static int vmlogrdr_open(struct inode *, struct file *);
static int vmlogrdr_release(struct inode *, struct file *);
static ssize_t vmlogrdr_read (struct file *filp, char __user *data,
size_t count, loff_t * ppos);
static const struct file_operations vmlogrdr_fops = {
.owner = THIS_MODULE,
.open = vmlogrdr_open,
.release = vmlogrdr_release,
.read = vmlogrdr_read,
.llseek = no_llseek,
};
static void vmlogrdr_iucv_path_complete(struct iucv_path *, u8 *ipuser);
static void vmlogrdr_iucv_path_severed(struct iucv_path *, u8 *ipuser);
static void vmlogrdr_iucv_message_pending(struct iucv_path *,
struct iucv_message *);
static struct iucv_handler vmlogrdr_iucv_handler = {
.path_complete = vmlogrdr_iucv_path_complete,
.path_severed = vmlogrdr_iucv_path_severed,
.message_pending = vmlogrdr_iucv_message_pending,
};
static DECLARE_WAIT_QUEUE_HEAD(conn_wait_queue);
static DECLARE_WAIT_QUEUE_HEAD(read_wait_queue);
/*
* pointer to system service private structure
* minor number 0 --> logrec
* minor number 1 --> account
* minor number 2 --> symptom
*/
static struct vmlogrdr_priv_t sys_ser[] = {
{ .system_service = "*LOGREC ",
.internal_name = "logrec",
.recording_name = "EREP",
.minor_num = 0,
.buffer_free = 1,
.priv_lock = __SPIN_LOCK_UNLOCKED(sys_ser[0].priv_lock),
.autorecording = 1,
.autopurge = 1,
},
{ .system_service = "*ACCOUNT",
.internal_name = "account",
.recording_name = "ACCOUNT",
.minor_num = 1,
.buffer_free = 1,
.priv_lock = __SPIN_LOCK_UNLOCKED(sys_ser[1].priv_lock),
.autorecording = 1,
.autopurge = 1,
},
{ .system_service = "*SYMPTOM",
.internal_name = "symptom",
.recording_name = "SYMPTOM",
.minor_num = 2,
.buffer_free = 1,
.priv_lock = __SPIN_LOCK_UNLOCKED(sys_ser[2].priv_lock),
.autorecording = 1,
.autopurge = 1,
}
};
#define MAXMINOR ARRAY_SIZE(sys_ser)
static char FENCE[] = {"EOR"};
static int vmlogrdr_major = 0;
static struct cdev *vmlogrdr_cdev = NULL;
static int recording_class_AB;
static void vmlogrdr_iucv_path_complete(struct iucv_path *path, u8 *ipuser)
{
struct vmlogrdr_priv_t * logptr = path->private;
spin_lock(&logptr->priv_lock);
logptr->connection_established = 1;
spin_unlock(&logptr->priv_lock);
wake_up(&conn_wait_queue);
}
static void vmlogrdr_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
{
struct vmlogrdr_priv_t * logptr = path->private;
u8 reason = (u8) ipuser[8];
pr_err("vmlogrdr: connection severed with reason %i\n", reason);
iucv_path_sever(path, NULL);
kfree(path);
logptr->path = NULL;
spin_lock(&logptr->priv_lock);
logptr->connection_established = 0;
logptr->iucv_path_severed = 1;
spin_unlock(&logptr->priv_lock);
wake_up(&conn_wait_queue);
/* just in case we're sleeping waiting for a record */
wake_up_interruptible(&read_wait_queue);
}
static void vmlogrdr_iucv_message_pending(struct iucv_path *path,
struct iucv_message *msg)
{
struct vmlogrdr_priv_t * logptr = path->private;
/*
* This function is the bottom half so it should be quick.
* Copy the external interrupt data into our local eib and increment
* the usage count
*/
spin_lock(&logptr->priv_lock);
memcpy(&logptr->local_interrupt_buffer, msg, sizeof(*msg));
atomic_inc(&logptr->receive_ready);
spin_unlock(&logptr->priv_lock);
wake_up_interruptible(&read_wait_queue);
}
static int vmlogrdr_get_recording_class_AB(void)
{
static const char cp_command[] = "QUERY COMMAND RECORDING ";
char cp_response[80];
char *tail;
int len,i;
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
len = strnlen(cp_response,sizeof(cp_response));
// now the parsing
tail=strnchr(cp_response,len,'=');
if (!tail)
return 0;
tail++;
if (!strncmp("ANY",tail,3))
return 1;
if (!strncmp("NONE",tail,4))
return 0;
/*
* expect comma separated list of classes here, if one of them
* is A or B return 1 otherwise 0
*/
for (i=tail-cp_response; i<len; i++)
if ( cp_response[i]=='A' || cp_response[i]=='B' )
return 1;
return 0;
}
static int vmlogrdr_recording(struct vmlogrdr_priv_t * logptr,
int action, int purge)
{
char cp_command[80];
char cp_response[160];
char *onoff, *qid_string;
int rc;
onoff = ((action == 1) ? "ON" : "OFF");
qid_string = ((recording_class_AB == 1) ? " QID * " : "");
/*
* The recording commands needs to be called with option QID
* for guests that have previlege classes A or B.
* Purging has to be done as separate step, because recording
* can't be switched on as long as records are on the queue.
* Doing both at the same time doesn't work.
*/
if (purge && (action == 1)) {
memset(cp_command, 0x00, sizeof(cp_command));
memset(cp_response, 0x00, sizeof(cp_response));
snprintf(cp_command, sizeof(cp_command),
"RECORDING %s PURGE %s",
logptr->recording_name,
qid_string);
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
}
memset(cp_command, 0x00, sizeof(cp_command));
memset(cp_response, 0x00, sizeof(cp_response));
snprintf(cp_command, sizeof(cp_command), "RECORDING %s %s %s",
logptr->recording_name,
onoff,
qid_string);
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
/* The recording command will usually answer with 'Command complete'
* on success, but when the specific service was never connected
* before then there might be an additional informational message
* 'HCPCRC8072I Recording entry not found' before the
* 'Command complete'. So I use strstr rather then the strncmp.
*/
if (strstr(cp_response,"Command complete"))
rc = 0;
else
rc = -EIO;
/*
* If we turn recording off, we have to purge any remaining records
* afterwards, as a large number of queued records may impact z/VM
* performance.
*/
if (purge && (action == 0)) {
memset(cp_command, 0x00, sizeof(cp_command));
memset(cp_response, 0x00, sizeof(cp_response));
snprintf(cp_command, sizeof(cp_command),
"RECORDING %s PURGE %s",
logptr->recording_name,
qid_string);
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
}
return rc;
}
static int vmlogrdr_open (struct inode *inode, struct file *filp)
{
int dev_num = 0;
struct vmlogrdr_priv_t * logptr = NULL;
int connect_rc = 0;
int ret;
dev_num = iminor(inode);
if (dev_num >= MAXMINOR)
return -ENODEV;
logptr = &sys_ser[dev_num];
/*
* only allow for blocking reads to be open
*/
if (filp->f_flags & O_NONBLOCK)
return -EOPNOTSUPP;
/* Besure this device hasn't already been opened */
spin_lock_bh(&logptr->priv_lock);
if (logptr->dev_in_use) {
spin_unlock_bh(&logptr->priv_lock);
return -EBUSY;
}
logptr->dev_in_use = 1;
logptr->connection_established = 0;
logptr->iucv_path_severed = 0;
atomic_set(&logptr->receive_ready, 0);
logptr->buffer_free = 1;
spin_unlock_bh(&logptr->priv_lock);
/* set the file options */
filp->private_data = logptr;
/* start recording for this service*/
if (logptr->autorecording) {
ret = vmlogrdr_recording(logptr,1,logptr->autopurge);
if (ret)
pr_warn("vmlogrdr: failed to start recording automatically\n");
}
/* create connection to the system service */
logptr->path = iucv_path_alloc(10, 0, GFP_KERNEL);
if (!logptr->path)
goto out_dev;
connect_rc = iucv_path_connect(logptr->path, &vmlogrdr_iucv_handler,
logptr->system_service, NULL, NULL,
logptr);
if (connect_rc) {
pr_err("vmlogrdr: iucv connection to %s "
"failed with rc %i \n",
logptr->system_service, connect_rc);
goto out_path;
}
/* We've issued the connect and now we must wait for a
* ConnectionComplete or ConnectinSevered Interrupt
* before we can continue to process.
*/
wait_event(conn_wait_queue, (logptr->connection_established)
|| (logptr->iucv_path_severed));
if (logptr->iucv_path_severed)
goto out_record;
nonseekable_open(inode, filp);
return 0;
out_record:
if (logptr->autorecording)
vmlogrdr_recording(logptr,0,logptr->autopurge);
out_path:
kfree(logptr->path); /* kfree(NULL) is ok. */
logptr->path = NULL;
out_dev:
logptr->dev_in_use = 0;
return -EIO;
}
static int vmlogrdr_release (struct inode *inode, struct file *filp)
{
int ret;
struct vmlogrdr_priv_t * logptr = filp->private_data;
iucv_path_sever(logptr->path, NULL);
kfree(logptr->path);
logptr->path = NULL;
if (logptr->autorecording) {
ret = vmlogrdr_recording(logptr,0,logptr->autopurge);
if (ret)
pr_warn("vmlogrdr: failed to stop recording automatically\n");
}
logptr->dev_in_use = 0;
return 0;
}
static int vmlogrdr_receive_data(struct vmlogrdr_priv_t *priv)
{
int rc, *temp;
/* we need to keep track of two data sizes here:
* The number of bytes we need to receive from iucv and
* the total number of bytes we actually write into the buffer.
*/
int user_data_count, iucv_data_count;
char * buffer;
if (atomic_read(&priv->receive_ready)) {
spin_lock_bh(&priv->priv_lock);
if (priv->residual_length){
/* receive second half of a record */
iucv_data_count = priv->residual_length;
user_data_count = 0;
buffer = priv->buffer;
} else {
/* receive a new record:
* We need to return the total length of the record
* + size of FENCE in the first 4 bytes of the buffer.
*/
iucv_data_count = priv->local_interrupt_buffer.length;
user_data_count = sizeof(int);
temp = (int*)priv->buffer;
*temp= iucv_data_count + sizeof(FENCE);
buffer = priv->buffer + sizeof(int);
}
/*
* If the record is bigger than our buffer, we receive only
* a part of it. We can get the rest later.
*/
if (iucv_data_count > NET_BUFFER_SIZE)
iucv_data_count = NET_BUFFER_SIZE;
rc = iucv_message_receive(priv->path,
&priv->local_interrupt_buffer,
0, buffer, iucv_data_count,
&priv->residual_length);
spin_unlock_bh(&priv->priv_lock);
/* An rc of 5 indicates that the record was bigger than
* the buffer, which is OK for us. A 9 indicates that the
* record was purged befor we could receive it.
*/
if (rc == 5)
rc = 0;
if (rc == 9)
atomic_set(&priv->receive_ready, 0);
} else {
rc = 1;
}
if (!rc) {
priv->buffer_free = 0;
user_data_count += iucv_data_count;
priv->current_position = priv->buffer;
if (priv->residual_length == 0){
/* the whole record has been captured,
* now add the fence */
atomic_dec(&priv->receive_ready);
buffer = priv->buffer + user_data_count;
memcpy(buffer, FENCE, sizeof(FENCE));
user_data_count += sizeof(FENCE);
}
priv->remaining = user_data_count;
}
return rc;
}
static ssize_t vmlogrdr_read(struct file *filp, char __user *data,
size_t count, loff_t * ppos)
{
int rc;
struct vmlogrdr_priv_t * priv = filp->private_data;
while (priv->buffer_free) {
rc = vmlogrdr_receive_data(priv);
if (rc) {
rc = wait_event_interruptible(read_wait_queue,
atomic_read(&priv->receive_ready));
if (rc)
return rc;
}
}
/* copy only up to end of record */
if (count > priv->remaining)
count = priv->remaining;
if (copy_to_user(data, priv->current_position, count))
return -EFAULT;
*ppos += count;
priv->current_position += count;
priv->remaining -= count;
/* if all data has been transferred, set buffer free */
if (priv->remaining == 0)
priv->buffer_free = 1;
return count;
}
static ssize_t vmlogrdr_autopurge_store(struct device * dev,
struct device_attribute *attr,
const char * buf, size_t count)
{
struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
ssize_t ret = count;
switch (buf[0]) {
case '0':
priv->autopurge=0;
break;
case '1':
priv->autopurge=1;
break;
default:
ret = -EINVAL;
}
return ret;
}
static ssize_t vmlogrdr_autopurge_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
return sprintf(buf, "%u\n", priv->autopurge);
}
static DEVICE_ATTR(autopurge, 0644, vmlogrdr_autopurge_show,
vmlogrdr_autopurge_store);
static ssize_t vmlogrdr_purge_store(struct device * dev,
struct device_attribute *attr,
const char * buf, size_t count)
{
char cp_command[80];
char cp_response[80];
struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
if (buf[0] != '1')
return -EINVAL;
memset(cp_command, 0x00, sizeof(cp_command));
memset(cp_response, 0x00, sizeof(cp_response));
/*
* The recording command needs to be called with option QID
* for guests that have previlege classes A or B.
* Other guests will not recognize the command and we have to
* issue the same command without the QID parameter.
*/
if (recording_class_AB)
snprintf(cp_command, sizeof(cp_command),
"RECORDING %s PURGE QID * ",
priv->recording_name);
else
snprintf(cp_command, sizeof(cp_command),
"RECORDING %s PURGE ",
priv->recording_name);
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
return count;
}
static DEVICE_ATTR(purge, 0200, NULL, vmlogrdr_purge_store);
static ssize_t vmlogrdr_autorecording_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
ssize_t ret = count;
switch (buf[0]) {
case '0':
priv->autorecording=0;
break;
case '1':
priv->autorecording=1;
break;
default:
ret = -EINVAL;
}
return ret;
}
static ssize_t vmlogrdr_autorecording_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
return sprintf(buf, "%u\n", priv->autorecording);
}
static DEVICE_ATTR(autorecording, 0644, vmlogrdr_autorecording_show,
vmlogrdr_autorecording_store);
static ssize_t vmlogrdr_recording_store(struct device * dev,
struct device_attribute *attr,
const char * buf, size_t count)
{
struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
ssize_t ret;
switch (buf[0]) {
case '0':
ret = vmlogrdr_recording(priv,0,0);
break;
case '1':
ret = vmlogrdr_recording(priv,1,0);
break;
default:
ret = -EINVAL;
}
if (ret)
return ret;
else
return count;
}
static DEVICE_ATTR(recording, 0200, NULL, vmlogrdr_recording_store);
static ssize_t recording_status_show(struct device_driver *driver, char *buf)
{
static const char cp_command[] = "QUERY RECORDING ";
int len;
cpcmd(cp_command, buf, 4096, NULL);
len = strlen(buf);
return len;
}
static DRIVER_ATTR_RO(recording_status);
static struct attribute *vmlogrdr_drv_attrs[] = {
&driver_attr_recording_status.attr,
NULL,
};
static struct attribute_group vmlogrdr_drv_attr_group = {
.attrs = vmlogrdr_drv_attrs,
};
static const struct attribute_group *vmlogrdr_drv_attr_groups[] = {
&vmlogrdr_drv_attr_group,
NULL,
};
static struct attribute *vmlogrdr_attrs[] = {
&dev_attr_autopurge.attr,
&dev_attr_purge.attr,
&dev_attr_autorecording.attr,
&dev_attr_recording.attr,
NULL,
};
static struct attribute_group vmlogrdr_attr_group = {
.attrs = vmlogrdr_attrs,
};
static const struct attribute_group *vmlogrdr_attr_groups[] = {
&vmlogrdr_attr_group,
NULL,
};
static struct class *vmlogrdr_class;
static struct device_driver vmlogrdr_driver = {
.name = "vmlogrdr",
.bus = &iucv_bus,
.groups = vmlogrdr_drv_attr_groups,
};
static int vmlogrdr_register_driver(void)
{
int ret;
/* Register with iucv driver */
ret = iucv_register(&vmlogrdr_iucv_handler, 1);
if (ret)
goto out;
ret = driver_register(&vmlogrdr_driver);
if (ret)
goto out_iucv;
vmlogrdr_class = class_create("vmlogrdr");
if (IS_ERR(vmlogrdr_class)) {
ret = PTR_ERR(vmlogrdr_class);
vmlogrdr_class = NULL;
goto out_driver;
}
return 0;
out_driver:
driver_unregister(&vmlogrdr_driver);
out_iucv:
iucv_unregister(&vmlogrdr_iucv_handler, 1);
out:
return ret;
}
static void vmlogrdr_unregister_driver(void)
{
class_destroy(vmlogrdr_class);
vmlogrdr_class = NULL;
driver_unregister(&vmlogrdr_driver);
iucv_unregister(&vmlogrdr_iucv_handler, 1);
}
static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
{
struct device *dev;
int ret;
dev = kzalloc(sizeof(struct device), GFP_KERNEL);
if (dev) {
dev_set_name(dev, "%s", priv->internal_name);
dev->bus = &iucv_bus;
dev->parent = iucv_root;
dev->driver = &vmlogrdr_driver;
dev->groups = vmlogrdr_attr_groups;
dev_set_drvdata(dev, priv);
/*
* The release function could be called after the
* module has been unloaded. It's _only_ task is to
* free the struct. Therefore, we specify kfree()
* directly here. (Probably a little bit obfuscating
* but legitime ...).
*/
dev->release = (void (*)(struct device *))kfree;
} else
return -ENOMEM;
ret = device_register(dev);
if (ret) {
put_device(dev);
return ret;
}
priv->class_device = device_create(vmlogrdr_class, dev,
MKDEV(vmlogrdr_major,
priv->minor_num),
priv, "%s", dev_name(dev));
if (IS_ERR(priv->class_device)) {
ret = PTR_ERR(priv->class_device);
priv->class_device=NULL;
device_unregister(dev);
return ret;
}
priv->device = dev;
return 0;
}
static int vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv)
{
device_destroy(vmlogrdr_class, MKDEV(vmlogrdr_major, priv->minor_num));
if (priv->device != NULL) {
device_unregister(priv->device);
priv->device=NULL;
}
return 0;
}
static int vmlogrdr_register_cdev(dev_t dev)
{
int rc = 0;
vmlogrdr_cdev = cdev_alloc();
if (!vmlogrdr_cdev) {
return -ENOMEM;
}
vmlogrdr_cdev->owner = THIS_MODULE;
vmlogrdr_cdev->ops = &vmlogrdr_fops;
rc = cdev_add(vmlogrdr_cdev, dev, MAXMINOR);
if (!rc)
return 0;
// cleanup: cdev is not fully registered, no cdev_del here!
kobject_put(&vmlogrdr_cdev->kobj);
vmlogrdr_cdev=NULL;
return rc;
}
static void vmlogrdr_cleanup(void)
{
int i;
if (vmlogrdr_cdev) {
cdev_del(vmlogrdr_cdev);
vmlogrdr_cdev=NULL;
}
for (i=0; i < MAXMINOR; ++i ) {
vmlogrdr_unregister_device(&sys_ser[i]);
free_page((unsigned long)sys_ser[i].buffer);
}
vmlogrdr_unregister_driver();
if (vmlogrdr_major) {
unregister_chrdev_region(MKDEV(vmlogrdr_major, 0), MAXMINOR);
vmlogrdr_major=0;
}
}
static int __init vmlogrdr_init(void)
{
int rc;
int i;
dev_t dev;
if (! MACHINE_IS_VM) {
pr_err("not running under VM, driver not loaded.\n");
return -ENODEV;
}
recording_class_AB = vmlogrdr_get_recording_class_AB();
rc = alloc_chrdev_region(&dev, 0, MAXMINOR, "vmlogrdr");
if (rc)
return rc;
vmlogrdr_major = MAJOR(dev);
rc=vmlogrdr_register_driver();
if (rc)
goto cleanup;
for (i=0; i < MAXMINOR; ++i ) {
sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (!sys_ser[i].buffer) {
rc = -ENOMEM;
break;
}
sys_ser[i].current_position = sys_ser[i].buffer;
rc=vmlogrdr_register_device(&sys_ser[i]);
if (rc)
break;
}
if (rc)
goto cleanup;
rc = vmlogrdr_register_cdev(dev);
if (rc)
goto cleanup;
return 0;
cleanup:
vmlogrdr_cleanup();
return rc;
}
static void __exit vmlogrdr_exit(void)
{
vmlogrdr_cleanup();
return;
}
module_init(vmlogrdr_init);
module_exit(vmlogrdr_exit);