1 /*
2 * Channel management functions.
3 *
4 * Copyright 2000-2014 Willy Tarreau <w@1wt.eu>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 */
12
13 #include <ctype.h>
14 #include <stdarg.h>
15 #include <stdio.h>
16 #include <string.h>
17
18 #include <common/config.h>
19 #include <common/buffer.h>
20
21 #include <proto/channel.h>
22
23
24 /* Schedule up to <bytes> more bytes to be forwarded via the channel without
25 * notifying the owner task. Any data pending in the buffer are scheduled to be
26 * sent as well, within the limit of the number of bytes to forward. This must
27 * be the only method to use to schedule bytes to be forwarded. If the requested
28 * number is too large, it is automatically adjusted. The number of bytes taken
29 * into account is returned. Directly touching ->to_forward will cause lockups
30 * when buf->o goes down to zero if nobody is ready to push the remaining data.
31 */
__channel_forward(struct channel * chn,unsigned long long bytes)32 unsigned long long __channel_forward(struct channel *chn, unsigned long long bytes)
33 {
34 unsigned int budget;
35 unsigned int forwarded;
36
37 /* This is more of a safety measure as it's not supposed to happen in
38 * regular code paths.
39 */
40 if (unlikely(chn->to_forward == CHN_INFINITE_FORWARD)) {
41 c_adv(chn, ci_data(chn));
42 return bytes;
43 }
44
45 /* Bound the transferred size to a 32-bit count since all our values
46 * are 32-bit, and we don't want to reach CHN_INFINITE_FORWARD.
47 */
48 budget = MIN(bytes, CHN_INFINITE_FORWARD - 1);
49
50 /* transfer as much as we can of buf->i */
51 forwarded = MIN(ci_data(chn), budget);
52 c_adv(chn, forwarded);
53 budget -= forwarded;
54
55 if (!budget)
56 return forwarded;
57
58 /* Now we must ensure chn->to_forward sats below CHN_INFINITE_FORWARD,
59 * which also implies it won't overflow. It's less operations in 64-bit.
60 */
61 bytes = (unsigned long long)chn->to_forward + budget;
62 if (bytes >= CHN_INFINITE_FORWARD)
63 bytes = CHN_INFINITE_FORWARD - 1;
64 budget = bytes - chn->to_forward;
65
66 chn->to_forward += budget;
67 forwarded += budget;
68 return forwarded;
69 }
70
71 /* writes <len> bytes from message <msg> to the channel's buffer. Returns -1 in
72 * case of success, -2 if the message is larger than the buffer size, or the
73 * number of bytes available otherwise. The send limit is automatically
74 * adjusted to the amount of data written. FIXME-20060521: handle unaligned
75 * data. Note: this function appends data to the buffer's output and possibly
76 * overwrites any pending input data which are assumed not to exist.
77 */
co_inject(struct channel * chn,const char * msg,int len)78 int co_inject(struct channel *chn, const char *msg, int len)
79 {
80 int max;
81
82 if (len == 0)
83 return -1;
84
85 if (len < 0 || len > c_size(chn)) {
86 /* we can't write this chunk and will never be able to, because
87 * it is larger than the buffer. This must be reported as an
88 * error. Then we return -2 so that writers that don't care can
89 * ignore it and go on, and others can check for this value.
90 */
91 return -2;
92 }
93
94 c_realign_if_empty(chn);
95 max = b_contig_space(&chn->buf);
96 if (len > max)
97 return max;
98
99 memcpy(co_tail(chn), msg, len);
100 b_add(&chn->buf, len);
101 c_adv(chn, len);
102 chn->total += len;
103 return -1;
104 }
105
106 /* Tries to copy character <c> into the channel's buffer after some length
107 * controls. The chn->o and to_forward pointers are updated. If the channel
108 * input is closed, -2 is returned. If there is not enough room left in the
109 * buffer, -1 is returned. Otherwise the number of bytes copied is returned
110 * (1). Channel flag READ_PARTIAL is updated if some data can be transferred.
111 */
ci_putchr(struct channel * chn,char c)112 int ci_putchr(struct channel *chn, char c)
113 {
114 if (unlikely(channel_input_closed(chn)))
115 return -2;
116
117 if (!channel_may_recv(chn))
118 return -1;
119
120 *ci_tail(chn) = c;
121
122 b_add(&chn->buf, 1);
123 chn->flags |= CF_READ_PARTIAL;
124
125 if (chn->to_forward >= 1) {
126 if (chn->to_forward != CHN_INFINITE_FORWARD)
127 chn->to_forward--;
128 c_adv(chn, 1);
129 }
130
131 chn->total++;
132 return 1;
133 }
134
135 /* Tries to copy block <blk> at once into the channel's buffer after length
136 * controls. The chn->o and to_forward pointers are updated. If the channel
137 * input is closed, -2 is returned. If the block is too large for this buffer,
138 * -3 is returned. If there is not enough room left in the buffer, -1 is
139 * returned. Otherwise the number of bytes copied is returned (0 being a valid
140 * number). Channel flag READ_PARTIAL is updated if some data can be
141 * transferred.
142 */
ci_putblk(struct channel * chn,const char * blk,int len)143 int ci_putblk(struct channel *chn, const char *blk, int len)
144 {
145 int max;
146
147 if (unlikely(channel_input_closed(chn)))
148 return -2;
149
150 if (len < 0)
151 return -3;
152
153 max = channel_recv_limit(chn);
154 if (unlikely(len > max - c_data(chn))) {
155 /* we can't write this chunk right now because the buffer is
156 * almost full or because the block is too large. Return the
157 * available space or -2 if impossible.
158 */
159 if (len > max)
160 return -3;
161
162 return -1;
163 }
164
165 if (unlikely(len == 0))
166 return 0;
167
168 /* OK so the data fits in the buffer in one or two blocks */
169 max = b_contig_space(&chn->buf);
170 memcpy(ci_tail(chn), blk, MIN(len, max));
171 if (len > max)
172 memcpy(c_orig(chn), blk + max, len - max);
173
174 b_add(&chn->buf, len);
175 channel_add_input(chn, len);
176 return len;
177 }
178
179 /* Gets one text line out of a channel's buffer from a stream interface.
180 * Return values :
181 * >0 : number of bytes read. Includes the \n if present before len or end.
182 * =0 : no '\n' before end found. <str> is left undefined.
183 * <0 : no more bytes readable because output is shut.
184 * The channel status is not changed. The caller must call co_skip() to
185 * update it. The '\n' is waited for as long as neither the buffer nor the
186 * output are full. If either of them is full, the string may be returned
187 * as is, without the '\n'.
188 */
co_getline(const struct channel * chn,char * str,int len)189 int co_getline(const struct channel *chn, char *str, int len)
190 {
191 int ret, max;
192 char *p;
193
194 ret = 0;
195 max = len;
196
197 /* closed or empty + imminent close = -1; empty = 0 */
198 if (unlikely((chn->flags & CF_SHUTW) || channel_is_empty(chn))) {
199 if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
200 ret = -1;
201 goto out;
202 }
203
204 p = co_head(chn);
205
206 if (max > co_data(chn)) {
207 max = co_data(chn);
208 str[max-1] = 0;
209 }
210 while (max) {
211 *str++ = *p;
212 ret++;
213 max--;
214
215 if (*p == '\n')
216 break;
217 p = b_next(&chn->buf, p);
218 }
219 if (ret > 0 && ret < len &&
220 (ret < co_data(chn) || channel_may_recv(chn)) &&
221 *(str-1) != '\n' &&
222 !(chn->flags & (CF_SHUTW|CF_SHUTW_NOW)))
223 ret = 0;
224 out:
225 if (max)
226 *str = 0;
227 return ret;
228 }
229
230 /* Gets one full block of data at once from a channel's buffer, optionally from
231 * a specific offset. Return values :
232 * >0 : number of bytes read, equal to requested size.
233 * =0 : not enough data available. <blk> is left undefined.
234 * <0 : no more bytes readable because output is shut.
235 * The channel status is not changed. The caller must call co_skip() to
236 * update it.
237 */
co_getblk(const struct channel * chn,char * blk,int len,int offset)238 int co_getblk(const struct channel *chn, char *blk, int len, int offset)
239 {
240 if (chn->flags & CF_SHUTW)
241 return -1;
242
243 if (len + offset > co_data(chn)) {
244 if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
245 return -1;
246 return 0;
247 }
248
249 return b_getblk(&chn->buf, blk, len, offset);
250 }
251
252 /* Gets one or two blocks of data at once from a channel's output buffer.
253 * Return values :
254 * >0 : number of blocks filled (1 or 2). blk1 is always filled before blk2.
255 * =0 : not enough data available. <blk*> are left undefined.
256 * <0 : no more bytes readable because output is shut.
257 * The channel status is not changed. The caller must call co_skip() to
258 * update it. Unused buffers are left in an undefined state.
259 */
co_getblk_nc(const struct channel * chn,const char ** blk1,size_t * len1,const char ** blk2,size_t * len2)260 int co_getblk_nc(const struct channel *chn, const char **blk1, size_t *len1, const char **blk2, size_t *len2)
261 {
262 if (unlikely(co_data(chn) == 0)) {
263 if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
264 return -1;
265 return 0;
266 }
267
268 return b_getblk_nc(&chn->buf, blk1, len1, blk2, len2, 0, co_data(chn));
269 }
270
271 /* Gets one text line out of a channel's output buffer from a stream interface.
272 * Return values :
273 * >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
274 * =0 : not enough data available.
275 * <0 : no more bytes readable because output is shut.
276 * The '\n' is waited for as long as neither the buffer nor the output are
277 * full. If either of them is full, the string may be returned as is, without
278 * the '\n'. Unused buffers are left in an undefined state.
279 */
co_getline_nc(const struct channel * chn,const char ** blk1,size_t * len1,const char ** blk2,size_t * len2)280 int co_getline_nc(const struct channel *chn,
281 const char **blk1, size_t *len1,
282 const char **blk2, size_t *len2)
283 {
284 int retcode;
285 int l;
286
287 retcode = co_getblk_nc(chn, blk1, len1, blk2, len2);
288 if (unlikely(retcode <= 0))
289 return retcode;
290
291 for (l = 0; l < *len1 && (*blk1)[l] != '\n'; l++);
292 if (l < *len1 && (*blk1)[l] == '\n') {
293 *len1 = l + 1;
294 return 1;
295 }
296
297 if (retcode >= 2) {
298 for (l = 0; l < *len2 && (*blk2)[l] != '\n'; l++);
299 if (l < *len2 && (*blk2)[l] == '\n') {
300 *len2 = l + 1;
301 return 2;
302 }
303 }
304
305 if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW)) {
306 /* If we have found no LF and the buffer is shut, then
307 * the resulting string is made of the concatenation of
308 * the pending blocks (1 or 2).
309 */
310 return retcode;
311 }
312
313 /* No LF yet and not shut yet */
314 return 0;
315 }
316
317 /* Gets one full block of data at once from a channel's input buffer.
318 * This function can return the data slitted in one or two blocks.
319 * Return values :
320 * >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
321 * =0 : not enough data available.
322 * <0 : no more bytes readable because input is shut.
323 */
ci_getblk_nc(const struct channel * chn,char ** blk1,size_t * len1,char ** blk2,size_t * len2)324 int ci_getblk_nc(const struct channel *chn,
325 char **blk1, size_t *len1,
326 char **blk2, size_t *len2)
327 {
328 if (unlikely(ci_data(chn) == 0)) {
329 if (chn->flags & CF_SHUTR)
330 return -1;
331 return 0;
332 }
333
334 if (unlikely(ci_head(chn) + ci_data(chn) > c_wrap(chn))) {
335 *blk1 = ci_head(chn);
336 *len1 = c_wrap(chn) - ci_head(chn);
337 *blk2 = c_orig(chn);
338 *len2 = ci_data(chn) - *len1;
339 return 2;
340 }
341
342 *blk1 = ci_head(chn);
343 *len1 = ci_data(chn);
344 return 1;
345 }
346
347 /* Gets one text line out of a channel's input buffer from a stream interface.
348 * Return values :
349 * >0 : number of blocks returned (1 or 2). blk1 is always filled before blk2.
350 * =0 : not enough data available.
351 * <0 : no more bytes readable because output is shut.
352 * The '\n' is waited for as long as neither the buffer nor the input are
353 * full. If either of them is full, the string may be returned as is, without
354 * the '\n'. Unused buffers are left in an undefined state.
355 */
ci_getline_nc(const struct channel * chn,char ** blk1,size_t * len1,char ** blk2,size_t * len2)356 int ci_getline_nc(const struct channel *chn,
357 char **blk1, size_t *len1,
358 char **blk2, size_t *len2)
359 {
360 int retcode;
361 int l;
362
363 retcode = ci_getblk_nc(chn, blk1, len1, blk2, len2);
364 if (unlikely(retcode <= 0))
365 return retcode;
366
367 for (l = 0; l < *len1 && (*blk1)[l] != '\n'; l++);
368 if (l < *len1 && (*blk1)[l] == '\n') {
369 *len1 = l + 1;
370 return 1;
371 }
372
373 if (retcode >= 2) {
374 for (l = 0; l < *len2 && (*blk2)[l] != '\n'; l++);
375 if (l < *len2 && (*blk2)[l] == '\n') {
376 *len2 = l + 1;
377 return 2;
378 }
379 }
380
381 if (chn->flags & CF_SHUTW) {
382 /* If we have found no LF and the buffer is shut, then
383 * the resulting string is made of the concatenation of
384 * the pending blocks (1 or 2).
385 */
386 return retcode;
387 }
388
389 /* No LF yet and not shut yet */
390 return 0;
391 }
392
393 /* Inserts <str> followed by "\r\n" at position <pos> relative to channel <c>'s
394 * input head. The <len> argument informs about the length of string <str> so
395 * that we don't have to measure it. <str> must be a valid pointer and must not
396 * include the trailing "\r\n".
397 *
398 * The number of bytes added is returned on success. 0 is returned on failure.
399 */
ci_insert_line2(struct channel * c,int pos,const char * str,int len)400 int ci_insert_line2(struct channel *c, int pos, const char *str, int len)
401 {
402 struct buffer *b = &c->buf;
403 char *dst = c_ptr(c, pos);
404 int delta;
405
406 delta = len + 2;
407
408 if (__b_tail(b) + delta >= b_wrap(b))
409 return 0; /* no space left */
410
411 if (b_data(b) &&
412 b_tail(b) + delta > b_head(b) &&
413 b_head(b) >= b_tail(b))
414 return 0; /* no space left before wrapping data */
415
416 /* first, protect the end of the buffer */
417 memmove(dst + delta, dst, b_tail(b) - dst);
418
419 /* now, copy str over dst */
420 memcpy(dst, str, len);
421 dst[len] = '\r';
422 dst[len + 1] = '\n';
423
424 b_add(b, delta);
425 return delta;
426 }
427
428 /*
429 * Local variables:
430 * c-indent-level: 8
431 * c-basic-offset: 8
432 * End:
433 */
434