- 根目录:
- drivers
- tty
- hvc
- hvc_iucv.c
/*
* hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver
*
* This HVC device driver provides terminal access using
* z/VM IUCV communication paths.
*
* Copyright IBM Corp. 2008, 2009
*
* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "hvc_iucv"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/types.h>
#include <linux/slab.h>
#include <asm/ebcdic.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/mempool.h>
#include <linux/moduleparam.h>
#include <linux/tty.h>
#include <linux/wait.h>
#include <net/iucv/iucv.h>
#include "hvc_console.h"
/* General device driver settings */
#define HVC_IUCV_MAGIC 0xc9e4c3e5
#define MAX_HVC_IUCV_LINES HVC_ALLOC_TTY_ADAPTERS
#define MEMPOOL_MIN_NR (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
/* IUCV TTY message */
#define MSG_VERSION 0x02 /* Message version */
#define MSG_TYPE_ERROR 0x01 /* Error message */
#define MSG_TYPE_TERMENV 0x02 /* Terminal environment variable */
#define MSG_TYPE_TERMIOS 0x04 /* Terminal IO struct update */
#define MSG_TYPE_WINSIZE 0x08 /* Terminal window size update */
#define MSG_TYPE_DATA 0x10 /* Terminal data */
struct iucv_tty_msg {
u8 version; /* Message version */
u8 type; /* Message type */
#define MSG_MAX_DATALEN ((u16)(~0))
u16 datalen; /* Payload length */
u8 data[]; /* Payload buffer */
} __attribute__((packed));
#define MSG_SIZE(s) ((s) + offsetof(struct iucv_tty_msg, data))
enum iucv_state_t {
IUCV_DISCONN = 0,
IUCV_CONNECTED = 1,
IUCV_SEVERED = 2,
};
enum tty_state_t {
TTY_CLOSED = 0,
TTY_OPENED = 1,
};
struct hvc_iucv_private {
struct hvc_struct *hvc; /* HVC struct reference */
u8 srv_name[8]; /* IUCV service name (ebcdic) */
unsigned char is_console; /* Linux console usage flag */
enum iucv_state_t iucv_state; /* IUCV connection status */
enum tty_state_t tty_state; /* TTY status */
struct iucv_path *path; /* IUCV path pointer */
spinlock_t lock; /* hvc_iucv_private lock */
#define SNDBUF_SIZE (PAGE_SIZE) /* must be < MSG_MAX_DATALEN */
void *sndbuf; /* send buffer */
size_t sndbuf_len; /* length of send buffer */
#define QUEUE_SNDBUF_DELAY (HZ / 25)
struct delayed_work sndbuf_work; /* work: send iucv msg(s) */
wait_queue_head_t sndbuf_waitq; /* wait for send completion */
struct list_head tty_outqueue; /* outgoing IUCV messages */
struct list_head tty_inqueue; /* incoming IUCV messages */
struct device *dev; /* device structure */
u8 info_path[16]; /* IUCV path info (dev attr) */
};
struct iucv_tty_buffer {
struct list_head list; /* list pointer */
struct iucv_message msg; /* store an IUCV message */
size_t offset; /* data buffer offset */
struct iucv_tty_msg *mbuf; /* buffer to store input/output data */
};
/* IUCV callback handler */
static int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
/* Kernel module parameter: use one terminal device as default */
static unsigned long hvc_iucv_devices = 1;
/* Array of allocated hvc iucv tty lines... */
static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
#define IUCV_HVC_CON_IDX (0)
/* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
#define MAX_VMID_FILTER (500)
static size_t hvc_iucv_filter_size;
static void *hvc_iucv_filter;
static const char *hvc_iucv_filter_string;
static DEFINE_RWLOCK(hvc_iucv_filter_lock);
/* Kmem cache and mempool for iucv_tty_buffer elements */
static struct kmem_cache *hvc_iucv_buffer_cache;
static mempool_t *hvc_iucv_mempool;
/* IUCV handler callback functions */
static struct iucv_handler hvc_iucv_handler = {
.path_pending = hvc_iucv_path_pending,
.path_severed = hvc_iucv_path_severed,
.message_complete = hvc_iucv_msg_complete,
.message_pending = hvc_iucv_msg_pending,
};
/**
* hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
* @num: The HVC virtual terminal number (vtermno)
*
* This function returns the struct hvc_iucv_private instance that corresponds
* to the HVC virtual terminal number specified as parameter @num.
*/
static struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
{
if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
return NULL;
return hvc_iucv_table[num - HVC_IUCV_MAGIC];
}
/**
* alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
* @size: Size of the internal buffer used to store data.
* @flags: Memory allocation flags passed to mempool.
*
* This function allocates a new struct iucv_tty_buffer element and, optionally,
* allocates an internal data buffer with the specified size @size.
* The internal data buffer is always allocated with GFP_DMA which is
* required for receiving and sending data with IUCV.
* Note: The total message size arises from the internal buffer size and the
* members of the iucv_tty_msg structure.
* The function returns NULL if memory allocation has failed.
*/
static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
{
struct iucv_tty_buffer *bufp;
bufp = mempool_alloc(hvc_iucv_mempool, flags);
if (!bufp)
return NULL;
memset(bufp, 0, sizeof(*bufp));
if (size > 0) {
bufp->msg.length = MSG_SIZE(size);
bufp->mbuf = kmalloc(bufp->msg.length, flags | GFP_DMA);
if (!bufp->mbuf) {
mempool_free(bufp, hvc_iucv_mempool);
return NULL;
}
bufp->mbuf->version = MSG_VERSION;
bufp->mbuf->type = MSG_TYPE_DATA;
bufp->mbuf->datalen = (u16) size;
}
return bufp;
}
/**
* destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
* @bufp: Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
*/
static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
{
kfree(bufp->mbuf);
mempool_free(bufp, hvc_iucv_mempool);
}
/**
* destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
* @list: List containing struct iucv_tty_buffer elements.
*/
static void destroy_tty_buffer_list(struct list_head *list)
{
struct iucv_tty_buffer *ent, *next;
list_for_each_entry_safe(ent, next, list, list) {
list_del(&ent->list);
destroy_tty_buffer(ent);
}
}
/**
* hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
* @priv: Pointer to struct hvc_iucv_private
* @buf: HVC buffer for writing received terminal data.
* @count: HVC buffer size.
* @has_more_data: Pointer to an int variable.
*
* The function picks up pending messages from the input queue and receives
* the message data that is then written to the specified buffer @buf.
* If the buffer size @count is less than the data message size, the
* message is kept on the input queue and @has_more_data is set to 1.
* If all message data has been written, the message is removed from
* the input queue.
*
* The function returns the number of bytes written to the terminal, zero if
* there are no pending data messages available or if there is no established
* IUCV path.
* If the IUCV path has been severed, then -EPIPE is returned to cause a
* hang up (that is issued by the HVC layer).
*/
static int hvc_iucv_write(struct hvc_iucv_private *priv,
char *buf, int count, int *has_more_data)
{
struct iucv_tty_buffer *rb;
int written;
int rc;
/* immediately return if there is no IUCV connection */
if (priv->iucv_state == IUCV_DISCONN)
return 0;
/* if the IUCV path has been severed, return -EPIPE to inform the
* HVC layer to hang up the tty device. */
if (priv->iucv_state == IUCV_SEVERED)
return -EPIPE;
/* check if there are pending messages */
if (list_empty(&priv->tty_inqueue))
return 0;
/* receive an iucv message and flip data to the tty (ldisc) */
rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
written = 0;
if (!rb->mbuf) { /* message not yet received ... */
/* allocate mem to store msg data; if no memory is available
* then leave the buffer on the list and re-try later */
rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC | GFP_DMA);
if (!rb->mbuf)
return -ENOMEM;
rc = __iucv_message_receive(priv->path, &rb->msg, 0,
rb->mbuf, rb->msg.length, NULL);
switch (rc) {
case 0: /* Successful */
break;
case 2: /* No message found */
case 9: /* Message purged */
break;
default:
written = -EIO;
}
/* remove buffer if an error has occurred or received data
* is not correct */
if (rc || (rb->mbuf->version != MSG_VERSION) ||
(rb->msg.length != MSG_SIZE(rb->mbuf->datalen)))
goto out_remove_buffer;
}
switch (rb->mbuf->type) {
case MSG_TYPE_DATA:
written = min_t(int, rb->mbuf->datalen - rb->offset, count);
memcpy(buf, rb->mbuf->data + rb->offset, written);
if (written < (rb->mbuf->datalen - rb->offset)) {
rb->offset += written;
*has_more_data = 1;
goto out_written;
}
break;
case MSG_TYPE_WINSIZE:
if (rb->mbuf->datalen != sizeof(struct winsize))
break;
/* The caller must ensure that the hvc is locked, which
* is the case when called from hvc_iucv_get_chars() */
__hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
break;
case MSG_TYPE_ERROR: /* ignored ... */
case MSG_TYPE_TERMENV: /* ignored ... */
case MSG_TYPE_TERMIOS: /* ignored ... */
break;
}
out_remove_buffer:
list_del(&rb->list);
destroy_tty_buffer(rb);
*has_more_data = !list_empty(&priv->tty_inqueue);
out_written:
return written;
}
/**
* hvc_iucv_get_chars() - HVC get_chars operation.
* @vtermno: HVC virtual terminal number.
* @buf: Pointer to a buffer to store data
* @count: Size of buffer available for writing
*
* The HVC thread calls this method to read characters from the back-end.
* If an IUCV communication path has been established, pending IUCV messages
* are received and data is copied into buffer @buf up to @count bytes.
*
* Locking: The routine gets called under an irqsave() spinlock; and
* the routine locks the struct hvc_iucv_private->lock to call
* helper functions.
*/
static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
{
struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
int written;
int has_more_data;
if (count <= 0)
return 0;
if (!priv)
return -ENODEV;
spin_lock(&priv->lock);
has_more_data = 0;
written = hvc_iucv_write(priv, buf, count, &has_more_data);
spin_unlock(&priv->lock);
/* if there are still messages on the queue... schedule another run */
if (has_more_data)
hvc_kick();
return written;
}
/**
* hvc_iucv_queue() - Buffer terminal data for sending.
* @priv: Pointer to struct hvc_iucv_private instance.
* @buf: Buffer containing data to send.
* @count: Size of buffer and amount of data to send.
*
* The function queues data for sending. To actually send the buffered data,
* a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
* The function returns the number of data bytes that has been buffered.
*
* If the device is not connected, data is ignored and the function returns
* @count.
* If the buffer is full, the function returns 0.
* If an existing IUCV communicaton path has been severed, -EPIPE is returned
* (that can be passed to HVC layer to cause a tty hangup).
*/
static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
int count)
{
size_t len;
if (priv->iucv_state == IUCV_DISCONN)
return count; /* ignore data */
if (priv->iucv_state == IUCV_SEVERED)
return -EPIPE;
len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
if (!len)
return 0;
memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
priv->sndbuf_len += len;
if (priv->iucv_state == IUCV_CONNECTED)
schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
return len;
}
/**
* hvc_iucv_send() - Send an IUCV message containing terminal data.
* @priv: Pointer to struct hvc_iucv_private instance.
*
* If an IUCV communication path has been established, the buffered output data
* is sent via an IUCV message and the number of bytes sent is returned.
* Returns 0 if there is no established IUCV communication path or
* -EPIPE if an existing IUCV communicaton path has been severed.
*/
static int hvc_iucv_send(struct hvc_iucv_private *priv)
{
struct iucv_tty_buffer *sb;
int rc, len;
if (priv->iucv_state == IUCV_SEVERED)
return -EPIPE;
if (priv->iucv_state == IUCV_DISCONN)
return -EIO;
if (!priv->sndbuf_len)
return 0;
/* allocate internal buffer to store msg data and also compute total
* message length */
sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
if (!sb)
return -ENOMEM;
memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
sb->mbuf->datalen = (u16) priv->sndbuf_len;
sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
list_add_tail(&sb->list, &priv->tty_outqueue);
rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
(void *) sb->mbuf, sb->msg.length);
if (rc) {
/* drop the message here; however we might want to handle
* 0x03 (msg limit reached) by trying again... */
list_del(&sb->list);
destroy_tty_buffer(sb);
}
len = priv->sndbuf_len;
priv->sndbuf_len = 0;
return len;
}
/**
* hvc_iucv_sndbuf_work() - Send buffered data over IUCV
* @work: Work structure.
*
* This work queue function sends buffered output data over IUCV and,
* if not all buffered data could be sent, reschedules itself.
*/
static void hvc_iucv_sndbuf_work(struct work_struct *work)
{
struct hvc_iucv_private *priv;
priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
if (!priv)
return;
spin_lock_bh(&priv->lock);
hvc_iucv_send(priv);
spin_unlock_bh(&priv->lock);
}
/**
* hvc_iucv_put_chars() - HVC put_chars operation.
* @vtermno: HVC virtual terminal number.
* @buf: Pointer to an buffer to read data from
* @count: Size of buffer available for reading
*
* The HVC thread calls this method to write characters to the back-end.
* The function calls hvc_iucv_queue() to queue terminal data for sending.
*
* Locking: The method gets called under an irqsave() spinlock; and
* locks struct hvc_iucv_private->lock.
*/
static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
{
struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
int queued;
if (count <= 0)
return 0;
if (!priv)
return -ENODEV;
spin_lock(&priv->lock);
queued = hvc_iucv_queue(priv, buf, count);
spin_unlock(&priv->lock);
return queued;
}
/**
* hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
* @hp: Pointer to the HVC device (struct hvc_struct)
* @id: Additional data (originally passed to hvc_alloc): the index of an struct
* hvc_iucv_private instance.
*
* The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
* instance that is derived from @id. Always returns 0.
*
* Locking: struct hvc_iucv_private->lock, spin_lock_bh
*/
static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
{
struct hvc_iucv_private *priv;
priv = hvc_iucv_get_private(id);
if (!priv)
return 0;
spin_lock_bh(&priv->lock);
priv->tty_state = TTY_OPENED;
spin_unlock_bh(&priv->lock);
return 0;
}
/**
* hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
* @priv: Pointer to the struct hvc_iucv_private instance.
*/
static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
{
destroy_tty_buffer_list(&priv->tty_outqueue);
destroy_tty_buffer_list(&priv->tty_inqueue);
priv->tty_state = TTY_CLOSED;
priv->iucv_state = IUCV_DISCONN;
priv->sndbuf_len = 0;
}
/**
* tty_outqueue_empty() - Test if the tty outq is empty
* @priv: Pointer to struct hvc_iucv_private instance.
*/
static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
{
int rc;
spin_lock_bh(&priv->lock);
rc = list_empty(&priv->tty_outqueue);
spin_unlock_bh(&priv->lock);
return rc;
}
/**
* flush_sndbuf_sync() - Flush send buffer and wait for completion
* @priv: Pointer to struct hvc_iucv_private instance.
*
* The routine cancels a pending sndbuf work, calls hvc_iucv_send()
* to flush any buffered terminal output data and waits for completion.
*/
static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
{
int sync_wait;
cancel_delayed_work_sync(&priv->sndbuf_work);
spin_lock_bh(&priv->lock);
hvc_iucv_send(priv); /* force sending buffered data */
sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
spin_unlock_bh(&priv->lock);
if (sync_wait)
wait_event_timeout(priv->sndbuf_waitq,
tty_outqueue_empty(priv), HZ/10);
}
/**
* hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
* @priv: Pointer to hvc_iucv_private structure
*
* This routine severs an existing IUCV communication path and hangs
* up the underlying HVC terminal device.
* The hang-up occurs only if an IUCV communication path is established;
* otherwise there is no need to hang up the terminal device.
*
* The IUCV HVC hang-up is separated into two steps:
* 1. After the IUCV path has been severed, the iucv_state is set to
* IUCV_SEVERED.
* 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
* IUCV_SEVERED state causes the tty hang-up in the HVC layer.
*
* If the tty has not yet been opened, clean up the hvc_iucv_private
* structure to allow re-connects.
* If the tty has been opened, let get_chars() return -EPIPE to signal
* the HVC layer to hang up the tty and, if so, wake up the HVC thread
* to call get_chars()...
*
* Special notes on hanging up a HVC terminal instantiated as console:
* Hang-up: 1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
* 2. do_tty_hangup() calls tty->ops->close() for console_filp
* => no hangup notifier is called by HVC (default)
* 2. hvc_close() returns because of tty_hung_up_p(filp)
* => no delete notifier is called!
* Finally, the back-end is not being notified, thus, the tty session is
* kept active (TTY_OPEN) to be ready for re-connects.
*
* Locking: spin_lock(&priv->lock) w/o disabling bh
*/
static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
{
struct iucv_path *path;
path = NULL;
spin_lock(&priv->lock);
if (priv->iucv_state == IUCV_CONNECTED) {
path = priv->path;
priv->path = NULL;
priv->iucv_state = IUCV_SEVERED;
if (priv->tty_state == TTY_CLOSED)
hvc_iucv_cleanup(priv);
else
/* console is special (see above) */
if (priv->is_console) {
hvc_iucv_cleanup(priv);
priv->tty_state = TTY_OPENED;
} else
hvc_kick();
}
spin_unlock(&priv->lock);
/* finally sever path (outside of priv->lock due to lock ordering) */
if (path) {
iucv_path_sever(path, NULL);
iucv_path_free(path);
}
}
/**
* hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
* @hp: Pointer to the HVC device (struct hvc_struct)
* @id: Additional data (originally passed to hvc_alloc):
* the index of an struct hvc_iucv_private instance.
*
* This routine notifies the HVC back-end that a tty hangup (carrier loss,
* virtual or otherwise) has occurred.
* The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
* to keep an existing IUCV communication path established.
* (Background: vhangup() is called from user space (by getty or login) to
* disable writing to the tty by other applications).
* If the tty has been opened and an established IUCV path has been severed
* (we caused the tty hangup), the function calls hvc_iucv_cleanup().
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
{
struct hvc_iucv_private *priv;
priv = hvc_iucv_get_private(id);
if (!priv)
return;
flush_sndbuf_sync(priv);
spin_lock_bh(&priv->lock);
/* NOTE: If the hangup was scheduled by ourself (from the iucv
* path_servered callback [IUCV_SEVERED]), we have to clean up
* our structure and to set state to TTY_CLOSED.
* If the tty was hung up otherwise (e.g. vhangup()), then we
* ignore this hangup and keep an established IUCV path open...
* (...the reason is that we are not able to connect back to the
* client if we disconnect on hang up) */
priv->tty_state = TTY_CLOSED;
if (priv->iucv_state == IUCV_SEVERED)
hvc_iucv_cleanup(priv);
spin_unlock_bh(&priv->lock);
}
/**
* hvc_iucv_dtr_rts() - HVC notifier for handling DTR/RTS
* @hp: Pointer the HVC device (struct hvc_struct)
* @raise: Non-zero to raise or zero to lower DTR/RTS lines
*
* This routine notifies the HVC back-end to raise or lower DTR/RTS
* lines. Raising DTR/RTS is ignored. Lowering DTR/RTS indicates to
* drop the IUCV connection (similar to hang up the modem).
*/
static void hvc_iucv_dtr_rts(struct hvc_struct *hp, int raise)
{
struct hvc_iucv_private *priv;
struct iucv_path *path;
/* Raising the DTR/RTS is ignored as IUCV connections can be
* established at any times.
*/
if (raise)
return;
priv = hvc_iucv_get_private(hp->vtermno);
if (!priv)
return;
/* Lowering the DTR/RTS lines disconnects an established IUCV
* connection.
*/
flush_sndbuf_sync(priv);
spin_lock_bh(&priv->lock);
path = priv->path; /* save reference to IUCV path */
priv->path = NULL;
priv->iucv_state = IUCV_DISCONN;
spin_unlock_bh(&priv->lock);
/* Sever IUCV path outside of priv->lock due to lock ordering of:
* priv->lock <--> iucv_table_lock */
if (path) {
iucv_path_sever(path, NULL);
iucv_path_free(path);
}
}
/**
* hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
* @hp: Pointer to the HVC device (struct hvc_struct)
* @id: Additional data (originally passed to hvc_alloc):
* the index of an struct hvc_iucv_private instance.
*
* This routine notifies the HVC back-end that the last tty device fd has been
* closed. The function cleans up tty resources. The clean-up of the IUCV
* connection is done in hvc_iucv_dtr_rts() and depends on the HUPCL termios
* control setting.
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
{
struct hvc_iucv_private *priv;
priv = hvc_iucv_get_private(id);
if (!priv)
return;
flush_sndbuf_sync(priv);
spin_lock_bh(&priv->lock);
destroy_tty_buffer_list(&priv->tty_outqueue);
destroy_tty_buffer_list(&priv->tty_inqueue);
priv->tty_state = TTY_CLOSED;
priv->sndbuf_len = 0;
spin_unlock_bh(&priv->lock);
}
/**
* hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
* @ipvmid: Originating z/VM user ID (right padded with blanks)
*
* Returns 0 if the z/VM user ID @ipvmid is allowed to connection, otherwise
* non-zero.
*/
static int hvc_iucv_filter_connreq(u8 ipvmid[8])
{
size_t i;
/* Note: default policy is ACCEPT if no filter is set */
if (!hvc_iucv_filter_size)
return 0;
for (i = 0; i < hvc_iucv_filter_size; i++)
if (0 == memcmp(ipvmid, hvc_iucv_filter + (8 * i), 8))
return 0;
return 1;
}
/**
* hvc_iucv_path_pending() - IUCV handler to process a connection request.
* @path: Pending path (struct iucv_path)
* @ipvmid: z/VM system identifier of originator
* @ipuser: User specified data for this path
* (AF_IUCV: port/service name and originator port)
*
* The function uses the @ipuser data to determine if the pending path belongs
* to a terminal managed by this device driver.
* If the path belongs to this driver, ensure that the terminal is not accessed
* multiple times (only one connection to a terminal is allowed).
* If the terminal is not yet connected, the pending path is accepted and is
* associated to the appropriate struct hvc_iucv_private instance.
*
* Returns 0 if @path belongs to a terminal managed by the this device driver;
* otherwise returns -ENODEV in order to dispatch this path to other handlers.
*
* Locking: struct hvc_iucv_private->lock
*/
static int hvc_iucv_path_pending(struct iucv_path *path,
u8 ipvmid[8], u8 ipuser[16])
{
struct hvc_iucv_private *priv, *tmp;
u8 wildcard[9] = "lnxhvc ";
int i, rc, find_unused;
u8 nuser_data[16];
u8 vm_user_id[9];
ASCEBC(wildcard, sizeof(wildcard));
find_unused = !memcmp(wildcard, ipuser, 8);
/* First, check if the pending path request is managed by this
* IUCV handler:
* - find a disconnected device if ipuser contains the wildcard
* - find the device that matches the terminal ID in ipuser
*/
priv = NULL;
for (i = 0; i < hvc_iucv_devices; i++) {
tmp = hvc_iucv_table[i];
if (!tmp)
continue;
if (find_unused) {
spin_lock(&tmp->lock);
if (tmp->iucv_state == IUCV_DISCONN)
priv = tmp;
spin_unlock(&tmp->lock);
} else if (!memcmp(tmp->srv_name, ipuser, 8))
priv = tmp;
if (priv)
break;
}
if (!priv)
return -ENODEV;
/* Enforce that ipvmid is allowed to connect to us */
read_lock(&hvc_iucv_filter_lock);
rc = hvc_iucv_filter_connreq(ipvmid);
read_unlock(&hvc_iucv_filter_lock);
if (rc) {
iucv_path_sever(path, ipuser);
iucv_path_free(path);
memcpy(vm_user_id, ipvmid, 8);
vm_user_id[8] = 0;
pr_info("A connection request from z/VM user ID %s "
"was refused\n", vm_user_id);
return 0;
}
spin_lock(&priv->lock);
/* If the terminal is already connected or being severed, then sever
* this path to enforce that there is only ONE established communication
* path per terminal. */
if (priv->iucv_state != IUCV_DISCONN) {
iucv_path_sever(path, ipuser);
iucv_path_free(path);
goto out_path_handled;
}
/* accept path */
memcpy(nuser_data, ipuser + 8, 8); /* remote service (for af_iucv) */
memcpy(nuser_data + 8, ipuser, 8); /* local service (for af_iucv) */
path->msglim = 0xffff; /* IUCV MSGLIMIT */
path->flags &= ~IUCV_IPRMDATA; /* TODO: use IUCV_IPRMDATA */
rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
if (rc) {
iucv_path_sever(path, ipuser);
iucv_path_free(path);
goto out_path_handled;
}
priv->path = path;
priv->iucv_state = IUCV_CONNECTED;
/* store path information */
memcpy(priv->info_path, ipvmid, 8);
memcpy(priv->info_path + 8, ipuser + 8, 8);
/* flush buffered output data... */
schedule_delayed_work(&priv->sndbuf_work, 5);
out_path_handled:
spin_unlock(&priv->lock);
return 0;
}
/**
* hvc_iucv_path_severed() - IUCV handler to process a path sever.
* @path: Pending path (struct iucv_path)
* @ipuser: User specified data for this path
* (AF_IUCV: port/service name and originator port)
*
* This function calls the hvc_iucv_hangup() function for the
* respective IUCV HVC terminal.
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
{
struct hvc_iucv_private *priv = path->private;
hvc_iucv_hangup(priv);
}
/**
* hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
* @path: Pending path (struct iucv_path)
* @msg: Pointer to the IUCV message
*
* The function puts an incoming message on the input queue for later
* processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
* If the tty has not yet been opened, the message is rejected.
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_msg_pending(struct iucv_path *path,
struct iucv_message *msg)
{
struct hvc_iucv_private *priv = path->private;
struct iucv_tty_buffer *rb;
/* reject messages that exceed max size of iucv_tty_msg->datalen */
if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
iucv_message_reject(path, msg);
return;
}
spin_lock(&priv->lock);
/* reject messages if tty has not yet been opened */
if (priv->tty_state == TTY_CLOSED) {
iucv_message_reject(path, msg);
goto unlock_return;
}
/* allocate tty buffer to save iucv msg only */
rb = alloc_tty_buffer(0, GFP_ATOMIC);
if (!rb) {
iucv_message_reject(path, msg);
goto unlock_return; /* -ENOMEM */
}
rb->msg = *msg;
list_add_tail(&rb->list, &priv->tty_inqueue);
hvc_kick(); /* wake up hvc thread */
unlock_return:
spin_unlock(&priv->lock);
}
/**
* hvc_iucv_msg_complete() - IUCV handler to process message completion
* @path: Pending path (struct iucv_path)
* @msg: Pointer to the IUCV message
*
* The function is called upon completion of message delivery to remove the
* message from the outqueue. Additional delivery information can be found
* msg->audit: rejected messages (0x040000 (IPADRJCT)), and
* purged messages (0x010000 (IPADPGNR)).
*
* Locking: struct hvc_iucv_private->lock
*/
static void hvc_iucv_msg_complete(struct iucv_path *path,
struct iucv_message *msg)
{
struct hvc_iucv_private *priv = path->private;
struct iucv_tty_buffer *ent, *next;
LIST_HEAD(list_remove);
spin_lock(&priv->lock);
list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
if (ent->msg.id == msg->id) {
list_move(&ent->list, &list_remove);
break;
}
wake_up(&priv->sndbuf_waitq);
spin_unlock(&priv->lock);
destroy_tty_buffer_list(&list_remove);
}
/**
* hvc_iucv_pm_freeze() - Freeze PM callback
* @dev: IUVC HVC terminal device
*
* Sever an established IUCV communication path and
* trigger a hang-up of the underlying HVC terminal.
*/
static int hvc_iucv_pm_freeze(struct device *dev)
{
struct hvc_iucv_private *priv = dev_get_drvdata(dev);
local_bh_disable();
hvc_iucv_hangup(priv);
local_bh_enable();
return 0;
}
/**
* hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
* @dev: IUVC HVC terminal device
*
* Wake up the HVC thread to trigger hang-up and respective
* HVC back-end notifier invocations.
*/
static int hvc_iucv_pm_restore_thaw(struct device *dev)
{
hvc_kick();
return 0;
}
static ssize_t hvc_iucv_dev_termid_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct hvc_iucv_private *priv = dev_get_drvdata(dev);
size_t len;
len = sizeof(priv->srv_name);
memcpy(buf, priv->srv_name, len);
EBCASC(buf, len);
buf[len++] = '\n';
return len;
}
static ssize_t hvc_iucv_dev_state_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct hvc_iucv_private *priv = dev_get_drvdata(dev);
return sprintf(buf, "%u:%u\n", priv->iucv_state, priv->tty_state);
}
static ssize_t hvc_iucv_dev_peer_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct hvc_iucv_private *priv = dev_get_drvdata(dev);
char vmid[9], ipuser[9];
memset(vmid, 0, sizeof(vmid));
memset(ipuser, 0, sizeof(ipuser));
spin_lock_bh(&priv->lock);
if (priv->iucv_state == IUCV_CONNECTED) {
memcpy(vmid, priv->info_path, 8);
memcpy(ipuser, priv->info_path + 8, 8);
}
spin_unlock_bh(&priv->lock);
EBCASC(ipuser, 8);
return sprintf(buf, "%s:%s\n", vmid, ipuser);
}
/* HVC operations */
static const struct hv_ops hvc_iucv_ops = {
.get_chars = hvc_iucv_get_chars,
.put_chars = hvc_iucv_put_chars,
.notifier_add = hvc_iucv_notifier_add,
.notifier_del = hvc_iucv_notifier_del,
.notifier_hangup = hvc_iucv_notifier_hangup,
.dtr_rts = hvc_iucv_dtr_rts,
};
/* Suspend / resume device operations */
static const struct dev_pm_ops hvc_iucv_pm_ops = {
.freeze = hvc_iucv_pm_freeze,
.thaw = hvc_iucv_pm_restore_thaw,
.restore = hvc_iucv_pm_restore_thaw,
};
/* IUCV HVC device driver */
static struct device_driver hvc_iucv_driver = {
.name = KMSG_COMPONENT,
.bus = &iucv_bus,
.pm = &hvc_iucv_pm_ops,
};
/* IUCV HVC device attributes */
static DEVICE_ATTR(termid, 0640, hvc_iucv_dev_termid_show, NULL);
static DEVICE_ATTR(state, 0640, hvc_iucv_dev_state_show, NULL);
static DEVICE_ATTR(peer, 0640, hvc_iucv_dev_peer_show, NULL);
static struct attribute *hvc_iucv_dev_attrs[] = {
&dev_attr_termid.attr,
&dev_attr_state.attr,
&dev_attr_peer.attr,
NULL,
};
static struct attribute_group hvc_iucv_dev_attr_group = {
.attrs = hvc_iucv_dev_attrs,
};
static const struct attribute_group *hvc_iucv_dev_attr_groups[] = {
&hvc_iucv_dev_attr_group,
NULL,
};
/**
* hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
* @id: hvc_iucv_table index
* @is_console: Flag if the instance is used as Linux console
*
* This function allocates a new hvc_iucv_private structure and stores
* the instance in hvc_iucv_table at index @id.
* Returns 0 on success; otherwise non-zero.
*/
static int __init hvc_iucv_alloc(int id, unsigned int is_console)
{
struct hvc_iucv_private *priv;
char name[9];
int rc;
priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
if (!priv)
return -ENOMEM;
spin_lock_init(&priv->lock);
INIT_LIST_HEAD(&priv->tty_outqueue);
INIT_LIST_HEAD(&priv->tty_inqueue);
INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
init_waitqueue_head(&priv->sndbuf_waitq);
priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
if (!priv->sndbuf) {
kfree(priv);
return -ENOMEM;
}
/* set console flag */
priv->is_console = is_console;
/* allocate hvc device */
priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /* PAGE_SIZE */
HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
if (IS_ERR(priv->hvc)) {
rc = PTR_ERR(priv->hvc);
goto out_error_hvc;
}
/* notify HVC thread instead of using polling */
priv->hvc->irq_requested = 1;
/* setup iucv related information */
snprintf(name, 9, "lnxhvc%-2d", id);
memcpy(priv->srv_name, name, 8);
ASCEBC(priv->srv_name, 8);
/* create and setup device */
priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
if (!priv->dev) {
rc = -ENOMEM;
goto out_error_dev;
}
dev_set_name(priv->dev, "hvc_iucv%d", id);
dev_set_drvdata(priv->dev, priv);
priv->dev->bus = &iucv_bus;
priv->dev->parent = iucv_root;
priv->dev->driver = &hvc_iucv_driver;
priv->dev->groups = hvc_iucv_dev_attr_groups;
priv->dev->release = (void (*)(struct device *)) kfree;
rc = device_register(priv->dev);
if (rc) {
put_device(priv->dev);
goto out_error_dev;
}
hvc_iucv_table[id] = priv;
return 0;
out_error_dev:
hvc_remove(priv->hvc);
out_error_hvc:
free_page((unsigned long) priv->sndbuf);
kfree(priv);
return rc;
}
/**
* hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
*/
static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
{
hvc_remove(priv->hvc);
device_unregister(priv->dev);
free_page((unsigned long) priv->sndbuf);
kfree(priv);
}
/**
* hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
* @filter: String containing a comma-separated list of z/VM user IDs
*/
static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
{
const char *nextdelim, *residual;
size_t len;
nextdelim = strchr(filter, ',');
if (nextdelim) {
len = nextdelim - filter;
residual = nextdelim + 1;
} else {
len = strlen(filter);
residual = filter + len;
}
if (len == 0)
return ERR_PTR(-EINVAL);
/* check for '\n' (if called from sysfs) */
if (filter[len - 1] == '\n')
len--;
if (len > 8)
return ERR_PTR(-EINVAL);
/* pad with blanks and save upper case version of user ID */
memset(dest, ' ', 8);
while (len--)
dest[len] = toupper(filter[len]);
return residual;
}
/**
* hvc_iucv_setup_filter() - Set up z/VM user ID filter
* @filter: String consisting of a comma-separated list of z/VM user IDs
*
* The function parses the @filter string and creates an array containing
* the list of z/VM user ID filter entries.
* Return code 0 means success, -EINVAL if the filter is syntactically
* incorrect, -ENOMEM if there was not enough memory to allocate the
* filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
*/
static int hvc_iucv_setup_filter(const char *val)
{
const char *residual;
int err;
size_t size, count;
void *array, *old_filter;
count = strlen(val);
if (count == 0 || (count == 1 && val[0] == '\n')) {
size = 0;
array = NULL;
goto out_replace_filter; /* clear filter */
}
/* count user IDs in order to allocate sufficient memory */
size = 1;
residual = val;
while ((residual = strchr(residual, ',')) != NULL) {
residual++;
size++;
}
/* check if the specified list exceeds the filter limit */
if (size > MAX_VMID_FILTER)
return -ENOSPC;
array = kzalloc(size * 8, GFP_KERNEL);
if (!array)
return -ENOMEM;
count = size;
residual = val;
while (*residual && count) {
residual = hvc_iucv_parse_filter(residual,
array + ((size - count) * 8));
if (IS_ERR(residual)) {
err = PTR_ERR(residual);
kfree(array);
goto out_err;
}
count--;
}
out_replace_filter:
write_lock_bh(&hvc_iucv_filter_lock);
old_filter = hvc_iucv_filter;
hvc_iucv_filter_size = size;
hvc_iucv_filter = array;
write_unlock_bh(&hvc_iucv_filter_lock);
kfree(old_filter);
err = 0;
out_err:
return err;
}
/**
* param_set_vmidfilter() - Set z/VM user ID filter parameter
* @val: String consisting of a comma-separated list of z/VM user IDs
* @kp: Kernel parameter pointing to hvc_iucv_filter array
*
* The function sets up the z/VM user ID filter specified as comma-separated
* list of user IDs in @val.
* Note: If it is called early in the boot process, @val is stored and
* parsed later in hvc_iucv_init().
*/
static int param_set_vmidfilter(const char *val, const struct kernel_param *kp)
{
int rc;
if (!MACHINE_IS_VM || !hvc_iucv_devices)
return -ENODEV;
if (!val)
return -EINVAL;
rc = 0;
if (slab_is_available())
rc = hvc_iucv_setup_filter(val);
else
hvc_iucv_filter_string = val; /* defer... */
return rc;
}
/**
* param_get_vmidfilter() - Get z/VM user ID filter
* @buffer: Buffer to store z/VM user ID filter,
* (buffer size assumption PAGE_SIZE)
* @kp: Kernel parameter pointing to the hvc_iucv_filter array
*
* The function stores the filter as a comma-separated list of z/VM user IDs
* in @buffer. Typically, sysfs routines call this function for attr show.
*/
static int param_get_vmidfilter(char *buffer, const struct kernel_param *kp)
{
int rc;
size_t index, len;
void *start, *end;
if (!MACHINE_IS_VM || !hvc_iucv_devices)
return -ENODEV;
rc = 0;
read_lock_bh(&hvc_iucv_filter_lock);
for (index = 0; index < hvc_iucv_filter_size; index++) {
start = hvc_iucv_filter + (8 * index);
end = memchr(start, ' ', 8);
len = (end) ? end - start : 8;
memcpy(buffer + rc, start, len);
rc += len;
buffer[rc++] = ',';
}
read_unlock_bh(&hvc_iucv_filter_lock);
if (rc)
buffer[--rc] = '\0'; /* replace last comma and update rc */
return rc;
}
#define param_check_vmidfilter(name, p) __param_check(name, p, void)
static struct kernel_param_ops param_ops_vmidfilter = {
.set = param_set_vmidfilter,
.get = param_get_vmidfilter,
};
/**
* hvc_iucv_init() - z/VM IUCV HVC device driver initialization
*/
static int __init hvc_iucv_init(void)
{
int rc;
unsigned int i;
if (!hvc_iucv_devices)
return -ENODEV;
if (!MACHINE_IS_VM) {
pr_notice("The z/VM IUCV HVC device driver cannot "
"be used without z/VM\n");
rc = -ENODEV;
goto out_error;
}
if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
pr_err("%lu is not a valid value for the hvc_iucv= "
"kernel parameter\n", hvc_iucv_devices);
rc = -EINVAL;
goto out_error;
}
/* register IUCV HVC device driver */
rc = driver_register(&hvc_iucv_driver);
if (rc)
goto out_error;
/* parse hvc_iucv_allow string and create z/VM user ID filter list */
if (hvc_iucv_filter_string) {
rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
switch (rc) {
case 0:
break;
case -ENOMEM:
pr_err("Allocating memory failed with "
"reason code=%d\n", 3);
goto out_error;
case -EINVAL:
pr_err("hvc_iucv_allow= does not specify a valid "
"z/VM user ID list\n");
goto out_error;
case -ENOSPC:
pr_err("hvc_iucv_allow= specifies too many "
"z/VM user IDs\n");
goto out_error;
default:
goto out_error;
}
}
hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
sizeof(struct iucv_tty_buffer),
0, 0, NULL);
if (!hvc_iucv_buffer_cache) {
pr_err("Allocating memory failed with reason code=%d\n", 1);
rc = -ENOMEM;
goto out_error;
}
hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
hvc_iucv_buffer_cache);
if (!hvc_iucv_mempool) {
pr_err("Allocating memory failed with reason code=%d\n", 2);
kmem_cache_destroy(hvc_iucv_buffer_cache);
rc = -ENOMEM;
goto out_error;
}
/* register the first terminal device as console
* (must be done before allocating hvc terminal devices) */
rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
if (rc) {
pr_err("Registering HVC terminal device as "
"Linux console failed\n");
goto out_error_memory;
}
/* allocate hvc_iucv_private structs */
for (i = 0; i < hvc_iucv_devices; i++) {
rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
if (rc) {
pr_err("Creating a new HVC terminal device "
"failed with error code=%d\n", rc);
goto out_error_hvc;
}
}
/* register IUCV callback handler */
rc = iucv_register(&hvc_iucv_handler, 0);
if (rc) {
pr_err("Registering IUCV handlers failed with error code=%d\n",
rc);
goto out_error_hvc;
}
return 0;
out_error_hvc:
for (i = 0; i < hvc_iucv_devices; i++)
if (hvc_iucv_table[i])
hvc_iucv_destroy(hvc_iucv_table[i]);
out_error_memory:
mempool_destroy(hvc_iucv_mempool);
kmem_cache_destroy(hvc_iucv_buffer_cache);
out_error:
kfree(hvc_iucv_filter);
hvc_iucv_devices = 0; /* ensure that we do not provide any device */
return rc;
}
/**
* hvc_iucv_config() - Parsing of hvc_iucv= kernel command line parameter
* @val: Parameter value (numeric)
*/
static int __init hvc_iucv_config(char *val)
{
return kstrtoul(val, 10, &hvc_iucv_devices);
}
device_initcall(hvc_iucv_init);
__setup("hvc_iucv=", hvc_iucv_config);
core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);