drivers/isdn/hysdn/hysdn_proclog.c

   1 /* $Id: hysdn_proclog.c,v 1.9.6.3 2001/09/23 22:24:54 kai Exp $
   2  *
   3  * Linux driver for HYSDN cards, /proc/net filesystem log functions.
   4  *
   5  * Author    Werner Cornelius (werner@titro.de) for Hypercope GmbH
   6  * Copyright 1999 by Werner Cornelius (werner@titro.de)
   7  *
   8  * This software may be used and distributed according to the terms
   9  * of the GNU General Public License, incorporated herein by reference.
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/poll.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/mutex.h>
  19 #include <linux/kernel.h>
  20
  21 #include "hysdn_defs.h"
  22
  23 /* the proc subdir for the interface is defined in the procconf module */
  24 extern struct proc_dir_entry *hysdn_proc_entry;
  25
  26 static DEFINE_MUTEX(hysdn_log_mutex);
  27 static void put_log_buffer(hysdn_card * card, char *cp);
  28
  29 /*************************************************/
  30 /* structure keeping ascii log for device output */
  31 /*************************************************/
  32 struct log_data {
  33         struct log_data *next;
  34         unsigned long usage_cnt;/* number of files still to work */
  35         void *proc_ctrl;        /* pointer to own control procdata structure */
  36         char log_start[2];      /* log string start (final len aligned by size) */
  37 };
  38
  39 /**********************************************/
  40 /* structure holding proc entrys for one card */
  41 /**********************************************/
  42 struct procdata {
  43         struct proc_dir_entry *log;     /* log entry */
  44         char log_name[15];      /* log filename */
  45         struct log_data *log_head, *log_tail;   /* head and tail for queue */
  46         int if_used;            /* open count for interface */
  47         int volatile del_lock;  /* lock for delete operations */
  48         unsigned char logtmp[LOG_MAX_LINELEN];
  49         wait_queue_head_t rd_queue;
  50 };
  51
  52
  53 /**********************************************/
  54 /* log function for cards error log interface */
  55 /**********************************************/
  56 void
  57 hysdn_card_errlog(hysdn_card * card, tErrLogEntry * logp, int maxsize)
  58 {
  59         char buf[ERRLOG_TEXT_SIZE + 40];
  60
  61         sprintf(buf, "LOG 0x%08lX 0x%08lX : %s\n", logp->ulErrType, logp->ulErrSubtype, logp->ucText);
  62         put_log_buffer(card, buf);      /* output the string */
  63 }                               /* hysdn_card_errlog */
  64
  65 /***************************************************/
  66 /* Log function using format specifiers for output */
  67 /***************************************************/
  68 void
  69 hysdn_addlog(hysdn_card * card, char *fmt,...)
  70 {
  71         struct procdata *pd = card->proclog;
  72         char *cp;
  73         va_list args;
  74
  75         if (!pd)
  76                 return;         /* log structure non existent */
  77
  78         cp = pd->logtmp;
  79         cp += sprintf(cp, "HYSDN: card %d ", card->myid);
  80
  81         va_start(args, fmt);
  82         cp += vsprintf(cp, fmt, args);
  83         va_end(args);
  84         *cp++ = '\n';
  85         *cp = 0;
  86
  87         if (card->debug_flags & DEB_OUT_SYSLOG)
  88                 printk(KERN_INFO "%s", pd->logtmp);
  89         else
  90                 put_log_buffer(card, pd->logtmp);
  91
  92 }                               /* hysdn_addlog */
  93
  94 /********************************************/
  95 /* put an log buffer into the log queue.    */
  96 /* This buffer will be kept until all files */
  97 /* opened for read got the contents.        */
  98 /* Flushes buffers not longer in use.       */
  99 /********************************************/
 100 static void
 101 put_log_buffer(hysdn_card * card, char *cp)
 102 {
 103         struct log_data *ib;
 104         struct procdata *pd = card->proclog;
 105         int i;
 106         unsigned long flags;
 107
 108         if (!pd)
 109                 return;
 110         if (!cp)
 111                 return;
 112         if (!*cp)
 113                 return;
 114         if (pd->if_used <= 0)
 115                 return;         /* no open file for read */
 116
 117         if (!(ib = kmalloc(sizeof(struct log_data) + strlen(cp), GFP_ATOMIC)))
 118                  return;        /* no memory */
 119         strcpy(ib->log_start, cp);      /* set output string */
 120         ib->next = NULL;
 121         ib->proc_ctrl = pd;     /* point to own control structure */
 122         spin_lock_irqsave(&card->hysdn_lock, flags);
 123         ib->usage_cnt = pd->if_used;
 124         if (!pd->log_head)
 125                 pd->log_head = ib;      /* new head */
 126         else
 127                 pd->log_tail->next = ib;        /* follows existing messages */
 128         pd->log_tail = ib;      /* new tail */
 129         i = pd->del_lock++;     /* get lock state */
 130         spin_unlock_irqrestore(&card->hysdn_lock, flags);
 131
 132         /* delete old entrys */
 133         if (!i)
 134                 while (pd->log_head->next) {
 135                         if ((pd->log_head->usage_cnt <= 0) &&
 136                             (pd->log_head->next->usage_cnt <= 0)) {
 137                                 ib = pd->log_head;
 138                                 pd->log_head = pd->log_head->next;
 139                                 kfree(ib);
 140                         } else
 141                                 break;
 142                 }               /* pd->log_head->next */
 143         pd->del_lock--;         /* release lock level */
 144         wake_up_interruptible(&(pd->rd_queue));         /* announce new entry */
 145 }                               /* put_log_buffer */
 146
 147
 148 /******************************/
 149 /* file operations and tables */
 150 /******************************/
 151
 152 /****************************************/
 153 /* write log file -> set log level bits */
 154 /****************************************/
 155 static ssize_t
 156 hysdn_log_write(struct file *file, const char __user *buf, size_t count, loff_t * off)
 157 {
 158         int rc;
 159         unsigned char valbuf[128];
 160         hysdn_card *card = file->private_data;
 161
 162         if (count > (sizeof(valbuf) - 1))
 163                 count = sizeof(valbuf) - 1;     /* limit length */
 164         if (copy_from_user(valbuf, buf, count))
 165                 return (-EFAULT);       /* copy failed */
 166
 167         valbuf[count] = 0;      /* terminating 0 */
 168
 169         rc = kstrtoul(valbuf, 0, &card->debug_flags);
 170         if (rc < 0)
 171                 return rc;
 172         hysdn_addlog(card, "debug set to 0x%lx", card->debug_flags);
 173         return (count);
 174 }                               /* hysdn_log_write */
 175
 176 /******************/
 177 /* read log file */
 178 /******************/
 179 static ssize_t
 180 hysdn_log_read(struct file *file, char __user *buf, size_t count, loff_t * off)
 181 {
 182         struct log_data *inf;
 183         int len;
 184         struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 185         struct procdata *pd = NULL;
 186         hysdn_card *card;
 187
 188         if (!*((struct log_data **) file->private_data)) {
 189                 if (file->f_flags & O_NONBLOCK)
 190                         return (-EAGAIN);
 191
 192                 /* sorry, but we need to search the card */
 193                 card = card_root;
 194                 while (card) {
 195                         pd = card->proclog;
 196                         if (pd->log == pde)
 197                                 break;
 198                         card = card->next;      /* search next entry */
 199                 }
 200                 if (card)
 201                         interruptible_sleep_on(&(pd->rd_queue));
 202                 else
 203                         return (-EAGAIN);
 204
 205         }
 206         if (!(inf = *((struct log_data **) file->private_data)))
 207                 return (0);
 208
 209         inf->usage_cnt--;       /* new usage count */
 210         file->private_data = &inf->next;        /* next structure */
 211         if ((len = strlen(inf->log_start)) <= count) {
 212                 if (copy_to_user(buf, inf->log_start, len))
 213                         return -EFAULT;
 214                 *off += len;
 215                 return (len);
 216         }
 217         return (0);
 218 }                               /* hysdn_log_read */
 219
 220 /******************/
 221 /* open log file */
 222 /******************/
 223 static int
 224 hysdn_log_open(struct inode *ino, struct file *filep)
 225 {
 226         hysdn_card *card;
 227         struct procdata *pd = NULL;
 228         unsigned long flags;
 229
 230         mutex_lock(&hysdn_log_mutex);
 231         card = card_root;
 232         while (card) {
 233                 pd = card->proclog;
 234                 if (pd->log == PDE(ino))
 235                         break;
 236                 card = card->next;      /* search next entry */
 237         }
 238         if (!card) {
 239                 mutex_unlock(&hysdn_log_mutex);
 240                 return (-ENODEV);       /* device is unknown/invalid */
 241         }
 242         filep->private_data = card;     /* remember our own card */
 243
 244         if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
 245                 /* write only access -> write log level only */
 246         } else if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
 247
 248                 /* read access -> log/debug read */
 249                 spin_lock_irqsave(&card->hysdn_lock, flags);
 250                 pd->if_used++;
 251                 if (pd->log_head)
 252                         filep->private_data = &pd->log_tail->next;
 253                 else
 254                         filep->private_data = &pd->log_head;
 255                 spin_unlock_irqrestore(&card->hysdn_lock, flags);
 256         } else {                /* simultaneous read/write access forbidden ! */
 257                 mutex_unlock(&hysdn_log_mutex);
 258                 return (-EPERM);        /* no permission this time */
 259         }
 260         mutex_unlock(&hysdn_log_mutex);
 261         return nonseekable_open(ino, filep);
 262 }                               /* hysdn_log_open */
 263
 264 /*******************************************************************************/
 265 /* close a cardlog file. If the file has been opened for exclusive write it is */
 266 /* assumed as pof data input and the pof loader is noticed about.              */
 267 /* Otherwise file is handled as log output. In this case the interface usage   */
 268 /* count is decremented and all buffers are noticed of closing. If this file   */
 269 /* was the last one to be closed, all buffers are freed.                       */
 270 /*******************************************************************************/
 271 static int
 272 hysdn_log_close(struct inode *ino, struct file *filep)
 273 {
 274         struct log_data *inf;
 275         struct procdata *pd;
 276         hysdn_card *card;
 277         int retval = 0;
 278
 279         mutex_lock(&hysdn_log_mutex);
 280         if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
 281                 /* write only access -> write debug level written */
 282                 retval = 0;     /* success */
 283         } else {
 284                 /* read access -> log/debug read, mark one further file as closed */
 285
 286                 pd = NULL;
 287                 inf = *((struct log_data **) filep->private_data);      /* get first log entry */
 288                 if (inf)
 289                         pd = (struct procdata *) inf->proc_ctrl;        /* still entries there */
 290                 else {
 291                         /* no info available -> search card */
 292                         card = card_root;
 293                         while (card) {
 294                                 pd = card->proclog;
 295                                 if (pd->log == PDE(ino))
 296                                         break;
 297                                 card = card->next;      /* search next entry */
 298                         }
 299                         if (card)
 300                                 pd = card->proclog;     /* pointer to procfs log */
 301                 }
 302                 if (pd)
 303                         pd->if_used--;  /* decrement interface usage count by one */
 304
 305                 while (inf) {
 306                         inf->usage_cnt--;       /* decrement usage count for buffers */
 307                         inf = inf->next;
 308                 }
 309
 310                 if (pd)
 311                         if (pd->if_used <= 0)   /* delete buffers if last file closed */
 312                                 while (pd->log_head) {
 313                                         inf = pd->log_head;
 314                                         pd->log_head = pd->log_head->next;
 315                                         kfree(inf);
 316                                 }
 317         }                       /* read access */
 318         mutex_unlock(&hysdn_log_mutex);
 319
 320         return (retval);
 321 }                               /* hysdn_log_close */
 322
 323 /*************************************************/
 324 /* select/poll routine to be able using select() */
 325 /*************************************************/
 326 static unsigned int
 327 hysdn_log_poll(struct file *file, poll_table * wait)
 328 {
 329         unsigned int mask = 0;
 330         struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
 331         hysdn_card *card;
 332         struct procdata *pd = NULL;
 333
 334         if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE)
 335                 return (mask);  /* no polling for write supported */
 336
 337         /* we need to search the card */
 338         card = card_root;
 339         while (card) {
 340                 pd = card->proclog;
 341                 if (pd->log == pde)
 342                         break;
 343                 card = card->next;      /* search next entry */
 344         }
 345         if (!card)
 346                 return (mask);  /* card not found */
 347
 348         poll_wait(file, &(pd->rd_queue), wait);
 349
 350         if (*((struct log_data **) file->private_data))
 351                 mask |= POLLIN | POLLRDNORM;
 352
 353         return mask;
 354 }                               /* hysdn_log_poll */
 355
 356 /**************************************************/
 357 /* table for log filesystem functions defined above. */
 358 /**************************************************/
 359 static const struct file_operations log_fops =
 360 {
 361         .owner          = THIS_MODULE,
 362         .llseek         = no_llseek,
 363         .read           = hysdn_log_read,
 364         .write          = hysdn_log_write,
 365         .poll           = hysdn_log_poll,
 366         .open           = hysdn_log_open,
 367         .release        = hysdn_log_close,
 368 };
 369
 370
 371 /***********************************************************************************/
 372 /* hysdn_proclog_init is called when the module is loaded after creating the cards */
 373 /* conf files.                                                                     */
 374 /***********************************************************************************/
 375 int
 376 hysdn_proclog_init(hysdn_card * card)
 377 {
 378         struct procdata *pd;
 379
 380         /* create a cardlog proc entry */
 381
 382         if ((pd = kzalloc(sizeof(struct procdata), GFP_KERNEL)) != NULL) {
 383                 sprintf(pd->log_name, "%s%d", PROC_LOG_BASENAME, card->myid);
 384                 pd->log = proc_create(pd->log_name,
 385                                 S_IFREG | S_IRUGO | S_IWUSR, hysdn_proc_entry,
 386                                 &log_fops);
 387
 388                 init_waitqueue_head(&(pd->rd_queue));
 389
 390                 card->proclog = (void *) pd;    /* remember procfs structure */
 391         }
 392         return (0);
 393 }                               /* hysdn_proclog_init */
 394
 395 /************************************************************************************/
 396 /* hysdn_proclog_release is called when the module is unloaded and before the cards */
 397 /* conf file is released                                                            */
 398 /* The module counter is assumed to be 0 !                                          */
 399 /************************************************************************************/
 400 void
 401 hysdn_proclog_release(hysdn_card * card)
 402 {
 403         struct procdata *pd;
 404
 405         if ((pd = (struct procdata *) card->proclog) != NULL) {
 406                 if (pd->log)
 407                         remove_proc_entry(pd->log_name, hysdn_proc_entry);
 408                 kfree(pd);      /* release memory */
 409                 card->proclog = NULL;
 410         }
 411 }                               /* hysdn_proclog_release */