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         hysdn_card *card = file->private_data;
 160
 161         rc = kstrtoul_from_user(buf, count, 0, &card->debug_flags);
 162         if (rc < 0)
 163                 return rc;
 164         hysdn_addlog(card, "debug set to 0x%lx", card->debug_flags);
 165         return (count);
 166 }                               /* hysdn_log_write */
 167
 168 /******************/
 169 /* read log file */
 170 /******************/
 171 static ssize_t
 172 hysdn_log_read(struct file *file, char __user *buf, size_t count, loff_t *off)
 173 {
 174         struct log_data *inf;
 175         int len;
 176         hysdn_card *card = PDE_DATA(file_inode(file));
 177
 178         if (!(inf = *((struct log_data **) file->private_data))) {
 179                 struct procdata *pd = card->proclog;
 180                 if (file->f_flags & O_NONBLOCK)
 181                         return (-EAGAIN);
 182
 183                 wait_event_interruptible(pd->rd_queue, (inf =
 184                                 *((struct log_data **) file->private_data)));
 185         }
 186         if (!inf)
 187                 return (0);
 188
 189         inf->usage_cnt--;       /* new usage count */
 190         file->private_data = &inf->next;        /* next structure */
 191         if ((len = strlen(inf->log_start)) <= count) {
 192                 if (copy_to_user(buf, inf->log_start, len))
 193                         return -EFAULT;
 194                 *off += len;
 195                 return (len);
 196         }
 197         return (0);
 198 }                               /* hysdn_log_read */
 199
 200 /******************/
 201 /* open log file */
 202 /******************/
 203 static int
 204 hysdn_log_open(struct inode *ino, struct file *filep)
 205 {
 206         hysdn_card *card = PDE_DATA(ino);
 207
 208         mutex_lock(&hysdn_log_mutex);
 209         if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
 210                 /* write only access -> write log level only */
 211                 filep->private_data = card;     /* remember our own card */
 212         } else if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
 213                 struct procdata *pd = card->proclog;
 214                 unsigned long flags;
 215
 216                 /* read access -> log/debug read */
 217                 spin_lock_irqsave(&card->hysdn_lock, flags);
 218                 pd->if_used++;
 219                 if (pd->log_head)
 220                         filep->private_data = &pd->log_tail->next;
 221                 else
 222                         filep->private_data = &pd->log_head;
 223                 spin_unlock_irqrestore(&card->hysdn_lock, flags);
 224         } else {                /* simultaneous read/write access forbidden ! */
 225                 mutex_unlock(&hysdn_log_mutex);
 226                 return (-EPERM);        /* no permission this time */
 227         }
 228         mutex_unlock(&hysdn_log_mutex);
 229         return nonseekable_open(ino, filep);
 230 }                               /* hysdn_log_open */
 231
 232 /*******************************************************************************/
 233 /* close a cardlog file. If the file has been opened for exclusive write it is */
 234 /* assumed as pof data input and the pof loader is noticed about.              */
 235 /* Otherwise file is handled as log output. In this case the interface usage   */
 236 /* count is decremented and all buffers are noticed of closing. If this file   */
 237 /* was the last one to be closed, all buffers are freed.                       */
 238 /*******************************************************************************/
 239 static int
 240 hysdn_log_close(struct inode *ino, struct file *filep)
 241 {
 242         struct log_data *inf;
 243         struct procdata *pd;
 244         hysdn_card *card;
 245         int retval = 0;
 246
 247         mutex_lock(&hysdn_log_mutex);
 248         if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
 249                 /* write only access -> write debug level written */
 250                 retval = 0;     /* success */
 251         } else {
 252                 /* read access -> log/debug read, mark one further file as closed */
 253
 254                 inf = *((struct log_data **) filep->private_data);      /* get first log entry */
 255                 if (inf)
 256                         pd = (struct procdata *) inf->proc_ctrl;        /* still entries there */
 257                 else {
 258                         /* no info available -> search card */
 259                         card = PDE_DATA(file_inode(filep));
 260                         pd = card->proclog;     /* pointer to procfs log */
 261                 }
 262                 if (pd)
 263                         pd->if_used--;  /* decrement interface usage count by one */
 264
 265                 while (inf) {
 266                         inf->usage_cnt--;       /* decrement usage count for buffers */
 267                         inf = inf->next;
 268                 }
 269
 270                 if (pd)
 271                         if (pd->if_used <= 0)   /* delete buffers if last file closed */
 272                                 while (pd->log_head) {
 273                                         inf = pd->log_head;
 274                                         pd->log_head = pd->log_head->next;
 275                                         kfree(inf);
 276                                 }
 277         }                       /* read access */
 278         mutex_unlock(&hysdn_log_mutex);
 279
 280         return (retval);
 281 }                               /* hysdn_log_close */
 282
 283 /*************************************************/
 284 /* select/poll routine to be able using select() */
 285 /*************************************************/
 286 static unsigned int
 287 hysdn_log_poll(struct file *file, poll_table *wait)
 288 {
 289         unsigned int mask = 0;
 290         hysdn_card *card = PDE_DATA(file_inode(file));
 291         struct procdata *pd = card->proclog;
 292
 293         if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE)
 294                 return (mask);  /* no polling for write supported */
 295
 296         poll_wait(file, &(pd->rd_queue), wait);
 297
 298         if (*((struct log_data **) file->private_data))
 299                 mask |= POLLIN | POLLRDNORM;
 300
 301         return mask;
 302 }                               /* hysdn_log_poll */
 303
 304 /**************************************************/
 305 /* table for log filesystem functions defined above. */
 306 /**************************************************/
 307 static const struct file_operations log_fops =
 308 {
 309         .owner          = THIS_MODULE,
 310         .llseek         = no_llseek,
 311         .read           = hysdn_log_read,
 312         .write          = hysdn_log_write,
 313         .poll           = hysdn_log_poll,
 314         .open           = hysdn_log_open,
 315         .release        = hysdn_log_close,
 316 };
 317
 318
 319 /***********************************************************************************/
 320 /* hysdn_proclog_init is called when the module is loaded after creating the cards */
 321 /* conf files.                                                                     */
 322 /***********************************************************************************/
 323 int
 324 hysdn_proclog_init(hysdn_card *card)
 325 {
 326         struct procdata *pd;
 327
 328         /* create a cardlog proc entry */
 329
 330         if ((pd = kzalloc(sizeof(struct procdata), GFP_KERNEL)) != NULL) {
 331                 sprintf(pd->log_name, "%s%d", PROC_LOG_BASENAME, card->myid);
 332                 pd->log = proc_create_data(pd->log_name,
 333                                       S_IFREG | S_IRUGO | S_IWUSR, hysdn_proc_entry,
 334                                       &log_fops, card);
 335
 336                 init_waitqueue_head(&(pd->rd_queue));
 337
 338                 card->proclog = (void *) pd;    /* remember procfs structure */
 339         }
 340         return (0);
 341 }                               /* hysdn_proclog_init */
 342
 343 /************************************************************************************/
 344 /* hysdn_proclog_release is called when the module is unloaded and before the cards */
 345 /* conf file is released                                                            */
 346 /* The module counter is assumed to be 0 !                                          */
 347 /************************************************************************************/
 348 void
 349 hysdn_proclog_release(hysdn_card *card)
 350 {
 351         struct procdata *pd;
 352
 353         if ((pd = (struct procdata *) card->proclog) != NULL) {
 354                 if (pd->log)
 355                         remove_proc_entry(pd->log_name, hysdn_proc_entry);
 356                 kfree(pd);      /* release memory */
 357                 card->proclog = NULL;
 358         }
 359 }                               /* hysdn_proclog_release */