1/*
2 * net/tipc/dbg.c: TIPC print buffer routines for debugging
3 *
4 * Copyright (c) 1996-2006, Ericsson AB
5 * Copyright (c) 2005-2006, Wind River Systems
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the names of the copyright holders nor the names of its
17 *    contributors may be used to endorse or promote products derived from
18 *    this software without specific prior written permission.
19 *
20 * Alternatively, this software may be distributed under the terms of the
21 * GNU General Public License ("GPL") version 2 as published by the Free
22 * Software Foundation.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 */
36
37#include "core.h"
38#include "config.h"
39#include "dbg.h"
40
41static char print_string[TIPC_PB_MAX_STR];
42static DEFINE_SPINLOCK(print_lock);
43
44static struct print_buf null_buf = { NULL, 0, NULL, NULL };
45struct print_buf *TIPC_NULL = &null_buf;
46
47static struct print_buf cons_buf = { NULL, 0, NULL, NULL };
48struct print_buf *TIPC_CONS = &cons_buf;
49
50static struct print_buf log_buf = { NULL, 0, NULL, NULL };
51struct print_buf *TIPC_LOG = &log_buf;
52
53
54#define FORMAT(PTR,LEN,FMT) \
55{\
56       va_list args;\
57       va_start(args, FMT);\
58       LEN = vsprintf(PTR, FMT, args);\
59       va_end(args);\
60       *(PTR + LEN) = '\0';\
61}
62
63/*
64 * Locking policy when using print buffers.
65 *
66 * The following routines use 'print_lock' for protection:
67 * 1) tipc_printf()  - to protect its print buffer(s) and 'print_string'
68 * 2) TIPC_TEE()     - to protect its print buffer(s)
69 * 3) tipc_dump()    - to protect its print buffer(s) and 'print_string'
70 * 4) tipc_log_XXX() - to protect TIPC_LOG
71 *
72 * All routines of the form tipc_printbuf_XXX() rely on the caller to prevent
73 * simultaneous use of the print buffer(s) being manipulated.
74 */
75
76/**
77 * tipc_printbuf_init - initialize print buffer to empty
78 * @pb: pointer to print buffer structure
79 * @raw: pointer to character array used by print buffer
80 * @size: size of character array
81 *
82 * Makes the print buffer a null device that discards anything written to it
83 * if the character array is too small (or absent).
84 */
85
86void tipc_printbuf_init(struct print_buf *pb, char *raw, u32 size)
87{
88	pb->buf = raw;
89	pb->crs = raw;
90	pb->size = size;
91	pb->next = NULL;
92
93	if (size < TIPC_PB_MIN_SIZE) {
94		pb->buf = NULL;
95	} else if (raw) {
96		pb->buf[0] = 0;
97		pb->buf[size-1] = ~0;
98	}
99}
100
101/**
102 * tipc_printbuf_reset - reinitialize print buffer to empty state
103 * @pb: pointer to print buffer structure
104 */
105
106void tipc_printbuf_reset(struct print_buf *pb)
107{
108	tipc_printbuf_init(pb, pb->buf, pb->size);
109}
110
111/**
112 * tipc_printbuf_empty - test if print buffer is in empty state
113 * @pb: pointer to print buffer structure
114 *
115 * Returns non-zero if print buffer is empty.
116 */
117
118int tipc_printbuf_empty(struct print_buf *pb)
119{
120	return (!pb->buf || (pb->crs == pb->buf));
121}
122
123/**
124 * tipc_printbuf_validate - check for print buffer overflow
125 * @pb: pointer to print buffer structure
126 *
127 * Verifies that a print buffer has captured all data written to it.
128 * If data has been lost, linearize buffer and prepend an error message
129 *
130 * Returns length of print buffer data string (including trailing NUL)
131 */
132
133int tipc_printbuf_validate(struct print_buf *pb)
134{
135	char *err = "\n\n*** PRINT BUFFER OVERFLOW ***\n\n";
136	char *cp_buf;
137	struct print_buf cb;
138
139	if (!pb->buf)
140		return 0;
141
142	if (pb->buf[pb->size - 1] == 0) {
143		cp_buf = kmalloc(pb->size, GFP_ATOMIC);
144		if (cp_buf != NULL){
145			tipc_printbuf_init(&cb, cp_buf, pb->size);
146			tipc_printbuf_move(&cb, pb);
147			tipc_printbuf_move(pb, &cb);
148			kfree(cp_buf);
149			memcpy(pb->buf, err, strlen(err));
150		} else {
151			tipc_printbuf_reset(pb);
152			tipc_printf(pb, err);
153		}
154	}
155	return (pb->crs - pb->buf + 1);
156}
157
158/**
159 * tipc_printbuf_move - move print buffer contents to another print buffer
160 * @pb_to: pointer to destination print buffer structure
161 * @pb_from: pointer to source print buffer structure
162 *
163 * Current contents of destination print buffer (if any) are discarded.
164 * Source print buffer becomes empty if a successful move occurs.
165 */
166
167void tipc_printbuf_move(struct print_buf *pb_to, struct print_buf *pb_from)
168{
169	int len;
170
171	/* Handle the cases where contents can't be moved */
172
173	if (!pb_to->buf)
174		return;
175
176	if (!pb_from->buf) {
177		tipc_printbuf_reset(pb_to);
178		return;
179	}
180
181	if (pb_to->size < pb_from->size) {
182		tipc_printbuf_reset(pb_to);
183		tipc_printf(pb_to, "*** PRINT BUFFER MOVE ERROR ***");
184		return;
185	}
186
187	/* Copy data from char after cursor to end (if used) */
188
189	len = pb_from->buf + pb_from->size - pb_from->crs - 2;
190	if ((pb_from->buf[pb_from->size-1] == 0) && (len > 0)) {
191		strcpy(pb_to->buf, pb_from->crs + 1);
192		pb_to->crs = pb_to->buf + len;
193	} else
194		pb_to->crs = pb_to->buf;
195
196	/* Copy data from start to cursor (always) */
197
198	len = pb_from->crs - pb_from->buf;
199	strcpy(pb_to->crs, pb_from->buf);
200	pb_to->crs += len;
201
202	tipc_printbuf_reset(pb_from);
203}
204
205/**
206 * tipc_printf - append formatted output to print buffer chain
207 * @pb: pointer to chain of print buffers (may be NULL)
208 * @fmt: formatted info to be printed
209 */
210
211void tipc_printf(struct print_buf *pb, const char *fmt, ...)
212{
213	int chars_to_add;
214	int chars_left;
215	char save_char;
216	struct print_buf *pb_next;
217
218	spin_lock_bh(&print_lock);
219	FORMAT(print_string, chars_to_add, fmt);
220	if (chars_to_add >= TIPC_PB_MAX_STR)
221		strcpy(print_string, "*** PRINT BUFFER STRING TOO LONG ***");
222
223	while (pb) {
224		if (pb == TIPC_CONS)
225			printk(print_string);
226		else if (pb->buf) {
227			chars_left = pb->buf + pb->size - pb->crs - 1;
228			if (chars_to_add <= chars_left) {
229				strcpy(pb->crs, print_string);
230				pb->crs += chars_to_add;
231			} else if (chars_to_add >= (pb->size - 1)) {
232				strcpy(pb->buf, print_string + chars_to_add + 1
233				       - pb->size);
234				pb->crs = pb->buf + pb->size - 1;
235			} else {
236				strcpy(pb->buf, print_string + chars_left);
237				save_char = print_string[chars_left];
238				print_string[chars_left] = 0;
239				strcpy(pb->crs, print_string);
240				print_string[chars_left] = save_char;
241				pb->crs = pb->buf + chars_to_add - chars_left;
242			}
243		}
244		pb_next = pb->next;
245		pb->next = NULL;
246		pb = pb_next;
247	}
248	spin_unlock_bh(&print_lock);
249}
250
251/**
252 * TIPC_TEE - perform next output operation on both print buffers
253 * @b0: pointer to chain of print buffers (may be NULL)
254 * @b1: pointer to print buffer to add to chain
255 *
256 * Returns pointer to print buffer chain.
257 */
258
259struct print_buf *TIPC_TEE(struct print_buf *b0, struct print_buf *b1)
260{
261	struct print_buf *pb = b0;
262
263	if (!b0 || (b0 == b1))
264		return b1;
265
266	spin_lock_bh(&print_lock);
267	while (pb->next) {
268		if ((pb->next == b1) || (pb->next == b0))
269			pb->next = pb->next->next;
270		else
271			pb = pb->next;
272	}
273	pb->next = b1;
274	spin_unlock_bh(&print_lock);
275	return b0;
276}
277
278/**
279 * print_to_console - write string of bytes to console in multiple chunks
280 */
281
282static void print_to_console(char *crs, int len)
283{
284	int rest = len;
285
286	while (rest > 0) {
287		int sz = rest < TIPC_PB_MAX_STR ? rest : TIPC_PB_MAX_STR;
288		char c = crs[sz];
289
290		crs[sz] = 0;
291		printk((const char *)crs);
292		crs[sz] = c;
293		rest -= sz;
294		crs += sz;
295	}
296}
297
298/**
299 * printbuf_dump - write print buffer contents to console
300 */
301
302static void printbuf_dump(struct print_buf *pb)
303{
304	int len;
305
306	if (!pb->buf) {
307		printk("*** PRINT BUFFER NOT ALLOCATED ***");
308		return;
309	}
310
311	/* Dump print buffer from char after cursor to end (if used) */
312
313	len = pb->buf + pb->size - pb->crs - 2;
314	if ((pb->buf[pb->size - 1] == 0) && (len > 0))
315		print_to_console(pb->crs + 1, len);
316
317	/* Dump print buffer from start to cursor (always) */
318
319	len = pb->crs - pb->buf;
320	print_to_console(pb->buf, len);
321}
322
323/**
324 * tipc_dump - dump non-console print buffer(s) to console
325 * @pb: pointer to chain of print buffers
326 */
327
328void tipc_dump(struct print_buf *pb, const char *fmt, ...)
329{
330	struct print_buf *pb_next;
331	int len;
332
333	spin_lock_bh(&print_lock);
334	FORMAT(print_string, len, fmt);
335	printk(print_string);
336
337	for (; pb; pb = pb->next) {
338		if (pb != TIPC_CONS) {
339			printk("\n---- Start of %s log dump ----\n\n",
340			       (pb == TIPC_LOG) ? "global" : "local");
341			printbuf_dump(pb);
342			tipc_printbuf_reset(pb);
343			printk("\n---- End of dump ----\n");
344		}
345		pb_next = pb->next;
346		pb->next = NULL;
347		pb = pb_next;
348	}
349	spin_unlock_bh(&print_lock);
350}
351
352/**
353 * tipc_log_stop - free up TIPC log print buffer
354 */
355
356void tipc_log_stop(void)
357{
358	spin_lock_bh(&print_lock);
359	if (TIPC_LOG->buf) {
360		kfree(TIPC_LOG->buf);
361		TIPC_LOG->buf = NULL;
362	}
363	spin_unlock_bh(&print_lock);
364}
365
366/**
367 * tipc_log_reinit - (re)initialize TIPC log print buffer
368 * @log_size: print buffer size to use
369 */
370
371void tipc_log_reinit(int log_size)
372{
373	tipc_log_stop();
374
375	if (log_size) {
376		if (log_size < TIPC_PB_MIN_SIZE)
377			log_size = TIPC_PB_MIN_SIZE;
378		spin_lock_bh(&print_lock);
379		tipc_printbuf_init(TIPC_LOG, kmalloc(log_size, GFP_ATOMIC),
380				   log_size);
381		spin_unlock_bh(&print_lock);
382	}
383}
384
385/**
386 * tipc_log_resize - reconfigure size of TIPC log buffer
387 */
388
389struct sk_buff *tipc_log_resize(const void *req_tlv_area, int req_tlv_space)
390{
391	u32 value;
392
393	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
394		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
395
396	value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
397	if (value != delimit(value, 0, 32768))
398		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
399						   " (log size must be 0-32768)");
400	tipc_log_reinit(value);
401	return tipc_cfg_reply_none();
402}
403
404/**
405 * tipc_log_dump - capture TIPC log buffer contents in configuration message
406 */
407
408struct sk_buff *tipc_log_dump(void)
409{
410	struct sk_buff *reply;
411
412	spin_lock_bh(&print_lock);
413	if (!TIPC_LOG->buf)
414		reply = tipc_cfg_reply_ultra_string("log not activated\n");
415	else if (tipc_printbuf_empty(TIPC_LOG))
416		reply = tipc_cfg_reply_ultra_string("log is empty\n");
417	else {
418		struct tlv_desc *rep_tlv;
419		struct print_buf pb;
420		int str_len;
421
422		str_len = min(TIPC_LOG->size, 32768u);
423		reply = tipc_cfg_reply_alloc(TLV_SPACE(str_len));
424		if (reply) {
425			rep_tlv = (struct tlv_desc *)reply->data;
426			tipc_printbuf_init(&pb, TLV_DATA(rep_tlv), str_len);
427			tipc_printbuf_move(&pb, TIPC_LOG);
428			str_len = strlen(TLV_DATA(rep_tlv)) + 1;
429			skb_put(reply, TLV_SPACE(str_len));
430			TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
431		}
432	}
433	spin_unlock_bh(&print_lock);
434	return reply;
435}
436