linux/drivers/isdn/hysdn/hysdn_proclog.c
Arjan van de Ven 2b8693c061 [PATCH] mark struct file_operations const 3
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:45 -08:00

439 lines
13 KiB
C

/* $Id: hysdn_proclog.c,v 1.9.6.3 2001/09/23 22:24:54 kai Exp $
*
* Linux driver for HYSDN cards, /proc/net filesystem log functions.
*
* Author Werner Cornelius (werner@titro.de) for Hypercope GmbH
* Copyright 1999 by Werner Cornelius (werner@titro.de)
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*
*/
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/pci.h>
#include <linux/smp_lock.h>
#include "hysdn_defs.h"
/* the proc subdir for the interface is defined in the procconf module */
extern struct proc_dir_entry *hysdn_proc_entry;
static void put_log_buffer(hysdn_card * card, char *cp);
/*************************************************/
/* structure keeping ascii log for device output */
/*************************************************/
struct log_data {
struct log_data *next;
unsigned long usage_cnt;/* number of files still to work */
void *proc_ctrl; /* pointer to own control procdata structure */
char log_start[2]; /* log string start (final len aligned by size) */
};
/**********************************************/
/* structure holding proc entrys for one card */
/**********************************************/
struct procdata {
struct proc_dir_entry *log; /* log entry */
char log_name[15]; /* log filename */
struct log_data *log_head, *log_tail; /* head and tail for queue */
int if_used; /* open count for interface */
int volatile del_lock; /* lock for delete operations */
unsigned char logtmp[LOG_MAX_LINELEN];
wait_queue_head_t rd_queue;
};
/**********************************************/
/* log function for cards error log interface */
/**********************************************/
void
hysdn_card_errlog(hysdn_card * card, tErrLogEntry * logp, int maxsize)
{
char buf[ERRLOG_TEXT_SIZE + 40];
sprintf(buf, "LOG 0x%08lX 0x%08lX : %s\n", logp->ulErrType, logp->ulErrSubtype, logp->ucText);
put_log_buffer(card, buf); /* output the string */
} /* hysdn_card_errlog */
/***************************************************/
/* Log function using format specifiers for output */
/***************************************************/
void
hysdn_addlog(hysdn_card * card, char *fmt,...)
{
struct procdata *pd = card->proclog;
char *cp;
va_list args;
if (!pd)
return; /* log structure non existent */
cp = pd->logtmp;
cp += sprintf(cp, "HYSDN: card %d ", card->myid);
va_start(args, fmt);
cp += vsprintf(cp, fmt, args);
va_end(args);
*cp++ = '\n';
*cp = 0;
if (card->debug_flags & DEB_OUT_SYSLOG)
printk(KERN_INFO "%s", pd->logtmp);
else
put_log_buffer(card, pd->logtmp);
} /* hysdn_addlog */
/********************************************/
/* put an log buffer into the log queue. */
/* This buffer will be kept until all files */
/* opened for read got the contents. */
/* Flushes buffers not longer in use. */
/********************************************/
static void
put_log_buffer(hysdn_card * card, char *cp)
{
struct log_data *ib;
struct procdata *pd = card->proclog;
int i;
unsigned long flags;
if (!pd)
return;
if (!cp)
return;
if (!*cp)
return;
if (pd->if_used <= 0)
return; /* no open file for read */
if (!(ib = kmalloc(sizeof(struct log_data) + strlen(cp), GFP_ATOMIC)))
return; /* no memory */
strcpy(ib->log_start, cp); /* set output string */
ib->next = NULL;
ib->proc_ctrl = pd; /* point to own control structure */
spin_lock_irqsave(&card->hysdn_lock, flags);
ib->usage_cnt = pd->if_used;
if (!pd->log_head)
pd->log_head = ib; /* new head */
else
pd->log_tail->next = ib; /* follows existing messages */
pd->log_tail = ib; /* new tail */
i = pd->del_lock++; /* get lock state */
spin_unlock_irqrestore(&card->hysdn_lock, flags);
/* delete old entrys */
if (!i)
while (pd->log_head->next) {
if ((pd->log_head->usage_cnt <= 0) &&
(pd->log_head->next->usage_cnt <= 0)) {
ib = pd->log_head;
pd->log_head = pd->log_head->next;
kfree(ib);
} else
break;
} /* pd->log_head->next */
pd->del_lock--; /* release lock level */
wake_up_interruptible(&(pd->rd_queue)); /* announce new entry */
} /* put_log_buffer */
/******************************/
/* file operations and tables */
/******************************/
/****************************************/
/* write log file -> set log level bits */
/****************************************/
static ssize_t
hysdn_log_write(struct file *file, const char __user *buf, size_t count, loff_t * off)
{
unsigned long u = 0;
int found = 0;
unsigned char *cp, valbuf[128];
long base = 10;
hysdn_card *card = (hysdn_card *) file->private_data;
if (count > (sizeof(valbuf) - 1))
count = sizeof(valbuf) - 1; /* limit length */
if (copy_from_user(valbuf, buf, count))
return (-EFAULT); /* copy failed */
valbuf[count] = 0; /* terminating 0 */
cp = valbuf;
if ((count > 2) && (valbuf[0] == '0') && (valbuf[1] == 'x')) {
cp += 2; /* pointer after hex modifier */
base = 16;
}
/* scan the input for debug flags */
while (*cp) {
if ((*cp >= '0') && (*cp <= '9')) {
found = 1;
u *= base; /* adjust to next digit */
u += *cp++ - '0';
continue;
}
if (base != 16)
break; /* end of number */
if ((*cp >= 'a') && (*cp <= 'f')) {
found = 1;
u *= base; /* adjust to next digit */
u += *cp++ - 'a' + 10;
continue;
}
break; /* terminated */
}
if (found) {
card->debug_flags = u; /* remember debug flags */
hysdn_addlog(card, "debug set to 0x%lx", card->debug_flags);
}
return (count);
} /* hysdn_log_write */
/******************/
/* read log file */
/******************/
static ssize_t
hysdn_log_read(struct file *file, char __user *buf, size_t count, loff_t * off)
{
struct log_data *inf;
int len;
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
struct procdata *pd = NULL;
hysdn_card *card;
if (!*((struct log_data **) file->private_data)) {
if (file->f_flags & O_NONBLOCK)
return (-EAGAIN);
/* sorry, but we need to search the card */
card = card_root;
while (card) {
pd = card->proclog;
if (pd->log == pde)
break;
card = card->next; /* search next entry */
}
if (card)
interruptible_sleep_on(&(pd->rd_queue));
else
return (-EAGAIN);
}
if (!(inf = *((struct log_data **) file->private_data)))
return (0);
inf->usage_cnt--; /* new usage count */
file->private_data = &inf->next; /* next structure */
if ((len = strlen(inf->log_start)) <= count) {
if (copy_to_user(buf, inf->log_start, len))
return -EFAULT;
*off += len;
return (len);
}
return (0);
} /* hysdn_log_read */
/******************/
/* open log file */
/******************/
static int
hysdn_log_open(struct inode *ino, struct file *filep)
{
hysdn_card *card;
struct procdata *pd = NULL;
unsigned long flags;
lock_kernel();
card = card_root;
while (card) {
pd = card->proclog;
if (pd->log == PDE(ino))
break;
card = card->next; /* search next entry */
}
if (!card) {
unlock_kernel();
return (-ENODEV); /* device is unknown/invalid */
}
filep->private_data = card; /* remember our own card */
if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
/* write only access -> write log level only */
} else if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
/* read access -> log/debug read */
spin_lock_irqsave(&card->hysdn_lock, flags);
pd->if_used++;
if (pd->log_head)
filep->private_data = &pd->log_tail->next;
else
filep->private_data = &pd->log_head;
spin_unlock_irqrestore(&card->hysdn_lock, flags);
} else { /* simultaneous read/write access forbidden ! */
unlock_kernel();
return (-EPERM); /* no permission this time */
}
unlock_kernel();
return nonseekable_open(ino, filep);
} /* hysdn_log_open */
/*******************************************************************************/
/* close a cardlog file. If the file has been opened for exclusive write it is */
/* assumed as pof data input and the pof loader is noticed about. */
/* Otherwise file is handled as log output. In this case the interface usage */
/* count is decremented and all buffers are noticed of closing. If this file */
/* was the last one to be closed, all buffers are freed. */
/*******************************************************************************/
static int
hysdn_log_close(struct inode *ino, struct file *filep)
{
struct log_data *inf;
struct procdata *pd;
hysdn_card *card;
int retval = 0;
unsigned long flags;
spinlock_t hysdn_lock = SPIN_LOCK_UNLOCKED;
lock_kernel();
if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
/* write only access -> write debug level written */
retval = 0; /* success */
} else {
/* read access -> log/debug read, mark one further file as closed */
pd = NULL;
spin_lock_irqsave(&hysdn_lock, flags);
inf = *((struct log_data **) filep->private_data); /* get first log entry */
if (inf)
pd = (struct procdata *) inf->proc_ctrl; /* still entries there */
else {
/* no info available -> search card */
card = card_root;
while (card) {
pd = card->proclog;
if (pd->log == PDE(ino))
break;
card = card->next; /* search next entry */
}
if (card)
pd = card->proclog; /* pointer to procfs log */
}
if (pd)
pd->if_used--; /* decrement interface usage count by one */
while (inf) {
inf->usage_cnt--; /* decrement usage count for buffers */
inf = inf->next;
}
spin_unlock_irqrestore(&hysdn_lock, flags);
if (pd)
if (pd->if_used <= 0) /* delete buffers if last file closed */
while (pd->log_head) {
inf = pd->log_head;
pd->log_head = pd->log_head->next;
kfree(inf);
}
} /* read access */
unlock_kernel();
return (retval);
} /* hysdn_log_close */
/*************************************************/
/* select/poll routine to be able using select() */
/*************************************************/
static unsigned int
hysdn_log_poll(struct file *file, poll_table * wait)
{
unsigned int mask = 0;
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
hysdn_card *card;
struct procdata *pd = NULL;
if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE)
return (mask); /* no polling for write supported */
/* we need to search the card */
card = card_root;
while (card) {
pd = card->proclog;
if (pd->log == pde)
break;
card = card->next; /* search next entry */
}
if (!card)
return (mask); /* card not found */
poll_wait(file, &(pd->rd_queue), wait);
if (*((struct log_data **) file->private_data))
mask |= POLLIN | POLLRDNORM;
return mask;
} /* hysdn_log_poll */
/**************************************************/
/* table for log filesystem functions defined above. */
/**************************************************/
static const struct file_operations log_fops =
{
.llseek = no_llseek,
.read = hysdn_log_read,
.write = hysdn_log_write,
.poll = hysdn_log_poll,
.open = hysdn_log_open,
.release = hysdn_log_close,
};
/***********************************************************************************/
/* hysdn_proclog_init is called when the module is loaded after creating the cards */
/* conf files. */
/***********************************************************************************/
int
hysdn_proclog_init(hysdn_card * card)
{
struct procdata *pd;
/* create a cardlog proc entry */
if ((pd = kzalloc(sizeof(struct procdata), GFP_KERNEL)) != NULL) {
sprintf(pd->log_name, "%s%d", PROC_LOG_BASENAME, card->myid);
if ((pd->log = create_proc_entry(pd->log_name, S_IFREG | S_IRUGO | S_IWUSR, hysdn_proc_entry)) != NULL) {
pd->log->proc_fops = &log_fops;
pd->log->owner = THIS_MODULE;
}
init_waitqueue_head(&(pd->rd_queue));
card->proclog = (void *) pd; /* remember procfs structure */
}
return (0);
} /* hysdn_proclog_init */
/************************************************************************************/
/* hysdn_proclog_release is called when the module is unloaded and before the cards */
/* conf file is released */
/* The module counter is assumed to be 0 ! */
/************************************************************************************/
void
hysdn_proclog_release(hysdn_card * card)
{
struct procdata *pd;
if ((pd = (struct procdata *) card->proclog) != NULL) {
if (pd->log)
remove_proc_entry(pd->log_name, hysdn_proc_entry);
kfree(pd); /* release memory */
card->proclog = NULL;
}
} /* hysdn_proclog_release */