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
hysdn_card_errlog(hysdn_card * card,tErrLogEntry * logp,int maxsize)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
hysdn_addlog(hysdn_card * card,char * fmt,...)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
put_log_buffer(hysdn_card * card,char * cp)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
hysdn_log_write(struct file * file,const char __user * buf,size_t count,loff_t * off)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
hysdn_log_read(struct file * file,char __user * buf,size_t count,loff_t * off)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
hysdn_log_open(struct inode * ino,struct file * filep)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
hysdn_log_close(struct inode * ino,struct file * filep)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
hysdn_log_poll(struct file * file,poll_table * wait)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
hysdn_proclog_init(hysdn_card * card)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
hysdn_proclog_release(hysdn_card * card)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 */
360