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 unsigned char logtmp[LOG_MAX_LINELEN];
48 wait_queue_head_t rd_queue;
49 };
50
51
52 /**********************************************/
53 /* log function for cards error log interface */
54 /**********************************************/
55 void
56 hysdn_card_errlog(hysdn_card *card, tErrLogEntry *logp, int maxsize)
57 {
58 char buf[ERRLOG_TEXT_SIZE + 40];
59
60 sprintf(buf, "LOG 0x%08lX 0x%08lX : %s\n", logp->ulErrType, logp->ulErrSubtype, logp->ucText);
61 put_log_buffer(card, buf); /* output the string */
62 } /* hysdn_card_errlog */
63
64 /***************************************************/
65 /* Log function using format specifiers for output */
66 /***************************************************/
67 void
68 hysdn_addlog(hysdn_card *card, char *fmt, ...)
69 {
70 struct procdata *pd = card->proclog;
71 char *cp;
72 va_list args;
73
74 if (!pd)
75 return; /* log structure non existent */
76
77 cp = pd->logtmp;
78 cp += sprintf(cp, "HYSDN: card %d ", card->myid);
79
80 va_start(args, fmt);
81 cp += vsprintf(cp, fmt, args);
82 va_end(args);
83 *cp++ = '\n';
84 *cp = 0;
85
86 if (card->debug_flags & DEB_OUT_SYSLOG)
87 printk(KERN_INFO "%s", pd->logtmp);
88 else
89 put_log_buffer(card, pd->logtmp);
90
91 } /* hysdn_addlog */
92
93 /********************************************/
94 /* put an log buffer into the log queue. */
95 /* This buffer will be kept until all files */
96 /* opened for read got the contents. */
97 /* Flushes buffers not longer in use. */
98 /********************************************/
99 static void
100 put_log_buffer(hysdn_card *card, char *cp)
101 {
102 struct log_data *ib;
103 struct procdata *pd = card->proclog;
104 unsigned long flags;
105
106 if (!pd)
107 return;
108 if (!cp)
109 return;
110 if (!*cp)
111 return;
112 if (pd->if_used <= 0)
113 return; /* no open file for read */
114
115 if (!(ib = kmalloc(sizeof(struct log_data) + strlen(cp), GFP_ATOMIC)))
116 return; /* no memory */
117 strcpy(ib->log_start, cp); /* set output string */
118 ib->next = NULL;
119 ib->proc_ctrl = pd; /* point to own control structure */
120 spin_lock_irqsave(&card->hysdn_lock, flags);
121 ib->usage_cnt = pd->if_used;
122 if (!pd->log_head)
123 pd->log_head = ib; /* new head */
124 else
125 pd->log_tail->next = ib; /* follows existing messages */
126 pd->log_tail = ib; /* new tail */
127
128 /* delete old entrys */
129 while (pd->log_head->next) {
130 if ((pd->log_head->usage_cnt <= 0) &&
131 (pd->log_head->next->usage_cnt <= 0)) {
132 ib = pd->log_head;
133 pd->log_head = pd->log_head->next;
134 kfree(ib);
135 } else {
136 break;
137 }
138 } /* pd->log_head->next */
139
140 spin_unlock_irqrestore(&card->hysdn_lock, flags);
141
142 wake_up_interruptible(&(pd->rd_queue)); /* announce new entry */
143 } /* put_log_buffer */
144
145
146 /******************************/
147 /* file operations and tables */
148 /******************************/
149
150 /****************************************/
151 /* write log file -> set log level bits */
152 /****************************************/
153 static ssize_t
154 hysdn_log_write(struct file *file, const char __user *buf, size_t count, loff_t *off)
155 {
156 int rc;
157 hysdn_card *card = file->private_data;
158
159 rc = kstrtoul_from_user(buf, count, 0, &card->debug_flags);
160 if (rc < 0)
161 return rc;
162 hysdn_addlog(card, "debug set to 0x%lx", card->debug_flags);
163 return (count);
164 } /* hysdn_log_write */
165
166 /******************/
167 /* read log file */
168 /******************/
169 static ssize_t
170 hysdn_log_read(struct file *file, char __user *buf, size_t count, loff_t *off)
171 {
172 struct log_data *inf;
173 int len;
174 hysdn_card *card = PDE_DATA(file_inode(file));
175
176 if (!(inf = *((struct log_data **) file->private_data))) {
177 struct procdata *pd = card->proclog;
178 if (file->f_flags & O_NONBLOCK)
179 return (-EAGAIN);
180
181 wait_event_interruptible(pd->rd_queue, (inf =
182 *((struct log_data **) file->private_data)));
183 }
184 if (!inf)
185 return (0);
186
187 inf->usage_cnt--; /* new usage count */
188 file->private_data = &inf->next; /* next structure */
189 if ((len = strlen(inf->log_start)) <= count) {
190 if (copy_to_user(buf, inf->log_start, len))
191 return -EFAULT;
192 *off += len;
193 return (len);
194 }
195 return (0);
196 } /* hysdn_log_read */
197
198 /******************/
199 /* open log file */
200 /******************/
201 static int
202 hysdn_log_open(struct inode *ino, struct file *filep)
203 {
204 hysdn_card *card = PDE_DATA(ino);
205
206 mutex_lock(&hysdn_log_mutex);
207 if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
208 /* write only access -> write log level only */
209 filep->private_data = card; /* remember our own card */
210 } else if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
211 struct procdata *pd = card->proclog;
212 unsigned long flags;
213
214 /* read access -> log/debug read */
215 spin_lock_irqsave(&card->hysdn_lock, flags);
216 pd->if_used++;
217 if (pd->log_head)
218 filep->private_data = &pd->log_tail->next;
219 else
220 filep->private_data = &pd->log_head;
221 spin_unlock_irqrestore(&card->hysdn_lock, flags);
222 } else { /* simultaneous read/write access forbidden ! */
223 mutex_unlock(&hysdn_log_mutex);
224 return (-EPERM); /* no permission this time */
225 }
226 mutex_unlock(&hysdn_log_mutex);
227 return nonseekable_open(ino, filep);
228 } /* hysdn_log_open */
229
230 /*******************************************************************************/
231 /* close a cardlog file. If the file has been opened for exclusive write it is */
232 /* assumed as pof data input and the pof loader is noticed about. */
233 /* Otherwise file is handled as log output. In this case the interface usage */
234 /* count is decremented and all buffers are noticed of closing. If this file */
235 /* was the last one to be closed, all buffers are freed. */
236 /*******************************************************************************/
237 static int
238 hysdn_log_close(struct inode *ino, struct file *filep)
239 {
240 struct log_data *inf;
241 struct procdata *pd;
242 hysdn_card *card;
243 int retval = 0;
244
245 mutex_lock(&hysdn_log_mutex);
246 if ((filep->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE) {
247 /* write only access -> write debug level written */
248 retval = 0; /* success */
249 } else {
250 /* read access -> log/debug read, mark one further file as closed */
251
252 inf = *((struct log_data **) filep->private_data); /* get first log entry */
253 if (inf)
254 pd = (struct procdata *) inf->proc_ctrl; /* still entries there */
255 else {
256 /* no info available -> search card */
257 card = PDE_DATA(file_inode(filep));
258 pd = card->proclog; /* pointer to procfs log */
259 }
260 if (pd)
261 pd->if_used--; /* decrement interface usage count by one */
262
263 while (inf) {
264 inf->usage_cnt--; /* decrement usage count for buffers */
265 inf = inf->next;
266 }
267
268 if (pd)
269 if (pd->if_used <= 0) /* delete buffers if last file closed */
270 while (pd->log_head) {
271 inf = pd->log_head;
272 pd->log_head = pd->log_head->next;
273 kfree(inf);
274 }
275 } /* read access */
276 mutex_unlock(&hysdn_log_mutex);
277
278 return (retval);
279 } /* hysdn_log_close */
280
281 /*************************************************/
282 /* select/poll routine to be able using select() */
283 /*************************************************/
284 static __poll_t
285 hysdn_log_poll(struct file *file, poll_table *wait)
286 {
287 __poll_t mask = 0;
288 hysdn_card *card = PDE_DATA(file_inode(file));
289 struct procdata *pd = card->proclog;
290
291 if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_WRITE)
292 return (mask); /* no polling for write supported */
293
294 poll_wait(file, &(pd->rd_queue), wait);
295
296 if (*((struct log_data **) file->private_data))
297 mask |= EPOLLIN | EPOLLRDNORM;
298
299 return mask;
300 } /* hysdn_log_poll */
301
302 /**************************************************/
303 /* table for log filesystem functions defined above. */
304 /**************************************************/
305 static const struct file_operations log_fops =
306 {
307 .owner = THIS_MODULE,
308 .llseek = no_llseek,
309 .read = hysdn_log_read,
310 .write = hysdn_log_write,
311 .poll = hysdn_log_poll,
312 .open = hysdn_log_open,
313 .release = hysdn_log_close,
314 };
315
316
317 /***********************************************************************************/
318 /* hysdn_proclog_init is called when the module is loaded after creating the cards */
319 /* conf files. */
320 /***********************************************************************************/
321 int
322 hysdn_proclog_init(hysdn_card *card)
323 {
324 struct procdata *pd;
325
326 /* create a cardlog proc entry */
327
328 if ((pd = kzalloc(sizeof(struct procdata), GFP_KERNEL)) != NULL) {
329 sprintf(pd->log_name, "%s%d", PROC_LOG_BASENAME, card->myid);
330 pd->log = proc_create_data(pd->log_name,
331 S_IFREG | S_IRUGO | S_IWUSR, hysdn_proc_entry,
332 &log_fops, card);
333
334 init_waitqueue_head(&(pd->rd_queue));
335
336 card->proclog = (void *) pd; /* remember procfs structure */
337 }
338 return (0);
339 } /* hysdn_proclog_init */
340
341 /************************************************************************************/
342 /* hysdn_proclog_release is called when the module is unloaded and before the cards */
343 /* conf file is released */
344 /* The module counter is assumed to be 0 ! */
345 /************************************************************************************/
346 void
347 hysdn_proclog_release(hysdn_card *card)
348 {
349 struct procdata *pd;
350
351 if ((pd = (struct procdata *) card->proclog) != NULL) {
352 if (pd->log)
353 remove_proc_entry(pd->log_name, hysdn_proc_entry);
354 kfree(pd); /* release memory */
355 card->proclog = NULL;
356 }
357 } /* hysdn_proclog_release */