summaryrefslogtreecommitdiff
path: root/openpcd/opcd_test/zebvty/buffer.c
blob: 0610ebbe4015de0743e337bb67f0362cdb2da0b8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
/*
 * Buffering of output and input. 
 * Copyright (C) 1998 Kunihiro Ishiguro
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 * 
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Zebra; see the file COPYING.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA. 
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stddef.h>
#include <sys/uio.h>

#include "buffer.h"
#include "vty.h"

/* Buffer master. */
struct buffer {
	/* Data list. */
	struct buffer_data *head;
	struct buffer_data *tail;

	/* Size of each buffer_data chunk. */
	size_t size;
};

/* Data container. */
struct buffer_data {
	struct buffer_data *next;

	/* Location to add new data. */
	size_t cp;

	/* Pointer to data not yet flushed. */
	size_t sp;

	/* Actual data stream (variable length). */
	unsigned char data[0];	/* real dimension is buffer->size */
};

/* It should always be true that: 0 <= sp <= cp <= size */

/* Default buffer size (used if none specified).  It is rounded up to the
   next page boundery. */
#define BUFFER_SIZE_DEFAULT		4096

#define BUFFER_DATA_FREE(D) free((D))

/* Make new buffer. */
struct buffer *buffer_new(size_t size)
{
	struct buffer *b;

	b = calloc(1, sizeof(struct buffer));

	if (size)
		b->size = size;
	else {
		static size_t default_size;
		if (!default_size) {
			long pgsz = sysconf(_SC_PAGESIZE);
			default_size =
			    ((((BUFFER_SIZE_DEFAULT - 1) / pgsz) + 1) * pgsz);
		}
		b->size = default_size;
	}

	return b;
}

/* Free buffer. */
void buffer_free(struct buffer *b)
{
	buffer_reset(b);
	free(b);
}

/* Make string clone. */
char *buffer_getstr(struct buffer *b)
{
	size_t totlen = 0;
	struct buffer_data *data;
	char *s;
	char *p;

	for (data = b->head; data; data = data->next)
		totlen += data->cp - data->sp;
	if (!(s = malloc(totlen + 1)))
		return NULL;
	p = s;
	for (data = b->head; data; data = data->next) {
		memcpy(p, data->data + data->sp, data->cp - data->sp);
		p += data->cp - data->sp;
	}
	*p = '\0';
	return s;
}

/* Return 1 if buffer is empty. */
int buffer_empty(struct buffer *b)
{
	return (b->head == NULL);
}

/* Clear and free all allocated data. */
void buffer_reset(struct buffer *b)
{
	struct buffer_data *data;
	struct buffer_data *next;

	for (data = b->head; data; data = next) {
		next = data->next;
		BUFFER_DATA_FREE(data);
	}
	b->head = b->tail = NULL;
}

/* Add buffer_data to the end of buffer. */
static struct buffer_data *buffer_add(struct buffer *b)
{
	struct buffer_data *d;

	d = malloc(offsetof(struct buffer_data, data[b->size]));
	if (!d)
		return NULL;
	d->cp = d->sp = 0;
	d->next = NULL;

	if (b->tail)
		b->tail->next = d;
	else
		b->head = d;
	b->tail = d;

	return d;
}

/* Write data to buffer. */
void buffer_put(struct buffer *b, const void *p, size_t size)
{
	struct buffer_data *data = b->tail;
	const char *ptr = p;

	/* We use even last one byte of data buffer. */
	while (size) {
		size_t chunk;

		/* If there is no data buffer add it. */
		if (data == NULL || data->cp == b->size)
			data = buffer_add(b);

		chunk =
		    ((size <=
		      (b->size - data->cp)) ? size : (b->size - data->cp));
		memcpy((data->data + data->cp), ptr, chunk);
		size -= chunk;
		ptr += chunk;
		data->cp += chunk;
	}
}

/* Insert character into the buffer. */
void buffer_putc(struct buffer *b, u_char c)
{
	buffer_put(b, &c, 1);
}

/* Put string to the buffer. */
void buffer_putstr(struct buffer *b, const char *c)
{
	buffer_put(b, c, strlen(c));
}

/* Keep flushing data to the fd until the buffer is empty or an error is
   encountered or the operation would block. */
buffer_status_t buffer_flush_all(struct buffer *b, int fd)
{
	buffer_status_t ret;
	struct buffer_data *head;
	size_t head_sp;

	if (!b->head)
		return BUFFER_EMPTY;
	head_sp = (head = b->head)->sp;
	/* Flush all data. */
	while ((ret = buffer_flush_available(b, fd)) == BUFFER_PENDING) {
		if ((b->head == head) && (head_sp == head->sp)
		    && (errno != EINTR))
			/* No data was flushed, so kernel buffer must be full. */
			return ret;
		head_sp = (head = b->head)->sp;
	}

	return ret;
}

#if 0
/* Flush enough data to fill a terminal window of the given scene (used only
   by vty telnet interface). */
buffer_status_t
buffer_flush_window(struct buffer * b, int fd, int width, int height,
		    int erase_flag, int no_more_flag)
{
	int nbytes;
	int iov_alloc;
	int iov_index;
	struct iovec *iov;
	struct iovec small_iov[3];
	char more[] = " --More-- ";
	char erase[] =
	    { 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
		' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
		0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08
	};
	struct buffer_data *data;
	int column;

	if (!b->head)
		return BUFFER_EMPTY;

	if (height < 1) {
		zlog_warn
		    ("%s called with non-positive window height %d, forcing to 1",
		     __func__, height);
		height = 1;
	} else if (height >= 2)
		height--;
	if (width < 1) {
		zlog_warn
		    ("%s called with non-positive window width %d, forcing to 1",
		     __func__, width);
		width = 1;
	}

	/* For erase and more data add two to b's buffer_data count. */
	if (b->head->next == NULL) {
		iov_alloc = sizeof(small_iov) / sizeof(small_iov[0]);
		iov = small_iov;
	} else {
		iov_alloc = ((height * (width + 2)) / b->size) + 10;
		iov = XMALLOC(MTYPE_TMP, iov_alloc * sizeof(*iov));
	}
	iov_index = 0;

	/* Previously print out is performed. */
	if (erase_flag) {
		iov[iov_index].iov_base = erase;
		iov[iov_index].iov_len = sizeof erase;
		iov_index++;
	}

	/* Output data. */
	column = 1;		/* Column position of next character displayed. */
	for (data = b->head; data && (height > 0); data = data->next) {
		size_t cp;

		cp = data->sp;
		while ((cp < data->cp) && (height > 0)) {
			/* Calculate lines remaining and column position after displaying
			   this character. */
			if (data->data[cp] == '\r')
				column = 1;
			else if ((data->data[cp] == '\n') || (column == width)) {
				column = 1;
				height--;
			} else
				column++;
			cp++;
		}
		iov[iov_index].iov_base = (char *)(data->data + data->sp);
		iov[iov_index++].iov_len = cp - data->sp;
		data->sp = cp;

		if (iov_index == iov_alloc)
			/* This should not ordinarily happen. */
		{
			iov_alloc *= 2;
			if (iov != small_iov) {
				zlog_warn("%s: growing iov array to %d; "
					  "width %d, height %d, size %lu",
					  __func__, iov_alloc, width, height,
					  (u_long) b->size);
				iov =
				    XREALLOC(MTYPE_TMP, iov,
					     iov_alloc * sizeof(*iov));
			} else {
				/* This should absolutely never occur. */
				zlog_err
				    ("%s: corruption detected: iov_small overflowed; "
				     "head %p, tail %p, head->next %p",
				     __func__, b->head, b->tail, b->head->next);
				iov =
				    XMALLOC(MTYPE_TMP,
					    iov_alloc * sizeof(*iov));
				memcpy(iov, small_iov, sizeof(small_iov));
			}
		}
	}

	/* In case of `more' display need. */
	if (b->tail && (b->tail->sp < b->tail->cp) && !no_more_flag) {
		iov[iov_index].iov_base = more;
		iov[iov_index].iov_len = sizeof more;
		iov_index++;
	}
#ifdef IOV_MAX
	/* IOV_MAX are normally defined in <sys/uio.h> , Posix.1g.
	   example: Solaris2.6 are defined IOV_MAX size at 16.     */
	{
		struct iovec *c_iov = iov;
		nbytes = 0;	/* Make sure it's initialized. */

		while (iov_index > 0) {
			int iov_size;

			iov_size =
			    ((iov_index > IOV_MAX) ? IOV_MAX : iov_index);
			if ((nbytes = writev(fd, c_iov, iov_size)) < 0) {
				zlog_warn("%s: writev to fd %d failed: %s",
					  __func__, fd, safe_strerror(errno));
				break;
			}

			/* move pointer io-vector */
			c_iov += iov_size;
			iov_index -= iov_size;
		}
	}
#else				/* IOV_MAX */
	if ((nbytes = writev(fd, iov, iov_index)) < 0)
		zlog_warn("%s: writev to fd %d failed: %s",
			  __func__, fd, safe_strerror(errno));
#endif				/* IOV_MAX */

	/* Free printed buffer data. */
	while (b->head && (b->head->sp == b->head->cp)) {
		struct buffer_data *del;
		if (!(b->head = (del = b->head)->next))
			b->tail = NULL;
		BUFFER_DATA_FREE(del);
	}

	if (iov != small_iov)
		XFREE(MTYPE_TMP, iov);

	return (nbytes < 0) ? BUFFER_ERROR :
	    (b->head ? BUFFER_PENDING : BUFFER_EMPTY);
}
#endif

/* This function (unlike other buffer_flush* functions above) is designed
to work with non-blocking sockets.  It does not attempt to write out
all of the queued data, just a "big" chunk.  It returns 0 if it was
able to empty out the buffers completely, 1 if more flushing is
required later, or -1 on a fatal write error. */
buffer_status_t buffer_flush_available(struct buffer * b, int fd)
{

/* These are just reasonable values to make sure a significant amount of
data is written.  There's no need to go crazy and try to write it all
in one shot. */
#ifdef IOV_MAX
#define MAX_CHUNKS ((IOV_MAX >= 16) ? 16 : IOV_MAX)
#else
#define MAX_CHUNKS 16
#endif
#define MAX_FLUSH 131072

	struct buffer_data *d;
	size_t written;
	struct iovec iov[MAX_CHUNKS];
	size_t iovcnt = 0;
	size_t nbyte = 0;

	for (d = b->head; d && (iovcnt < MAX_CHUNKS) && (nbyte < MAX_FLUSH);
	     d = d->next, iovcnt++) {
		iov[iovcnt].iov_base = d->data + d->sp;
		nbyte += (iov[iovcnt].iov_len = d->cp - d->sp);
	}

	if (!nbyte)
		/* No data to flush: should we issue a warning message? */
		return BUFFER_EMPTY;

	/* only place where written should be sign compared */
	if ((ssize_t) (written = writev(fd, iov, iovcnt)) < 0) {
		if (ERRNO_IO_RETRY(errno))
			/* Calling code should try again later. */
			return BUFFER_PENDING;
		return BUFFER_ERROR;
	}

	/* Free printed buffer data. */
	while (written > 0) {
		struct buffer_data *d;
		if (!(d = b->head))
			break;
		if (written < d->cp - d->sp) {
			d->sp += written;
			return BUFFER_PENDING;
		}

		written -= (d->cp - d->sp);
		if (!(b->head = d->next))
			b->tail = NULL;
		BUFFER_DATA_FREE(d);
	}

	return b->head ? BUFFER_PENDING : BUFFER_EMPTY;

#undef MAX_CHUNKS
#undef MAX_FLUSH
}

buffer_status_t
buffer_write(struct buffer * b, int fd, const void *p, size_t size)
{
	ssize_t nbytes;

#if 0
	/* Should we attempt to drain any previously buffered data?  This could help reduce latency in pushing out the data if we are stuck in a long-running thread that is preventing the main select loop from calling the flush thread... */

	if (b->head && (buffer_flush_available(b, fd) == BUFFER_ERROR))
		return BUFFER_ERROR;
#endif
	if (b->head)
		/* Buffer is not empty, so do not attempt to write the new data. */
		nbytes = 0;
	else if ((nbytes = write(fd, p, size)) < 0) {
		if (ERRNO_IO_RETRY(errno))
			nbytes = 0;
		else
			return BUFFER_ERROR;
	}
	/* Add any remaining data to the buffer. */
	{
		size_t written = nbytes;
		if (written < size)
			buffer_put(b, ((const char *)p) + written,
				   size - written);
	}
	return b->head ? BUFFER_PENDING : BUFFER_EMPTY;
}
personal git repositories of Harald Welte. Your mileage may vary