third_party/libevent/buffer.c

   1 /*
   2  * Copyright (c) 2002, 2003 Niels Provos <provos@citi.umich.edu>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #ifdef WIN32
  33 #include <winsock2.h>
  34 #include <windows.h>
  35 #endif
  36
  37 #ifdef HAVE_VASPRINTF
  38 /* If we have vasprintf, we need to define this before we include stdio.h. */
  39 #define _GNU_SOURCE
  40 #endif
  41
  42 #include <sys/types.h>
  43
  44 #ifdef HAVE_SYS_TIME_H
  45 #include <sys/time.h>
  46 #endif
  47
  48 #ifdef HAVE_SYS_IOCTL_H
  49 #include <sys/ioctl.h>
  50 #endif
  51
  52 #include <assert.h>
  53 #include <errno.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #ifdef HAVE_STDARG_H
  58 #include <stdarg.h>
  59 #endif
  60 #ifdef HAVE_UNISTD_H
  61 #include <unistd.h>
  62 #endif
  63
  64 #include "event.h"
  65 #include "config.h"
  66 #include "evutil.h"
  67
  68 struct evbuffer *
  69 evbuffer_new(void)
  70 {
  71         struct evbuffer *buffer;
  72
  73         buffer = calloc(1, sizeof(struct evbuffer));
  74
  75         return (buffer);
  76 }
  77
  78 void
  79 evbuffer_free(struct evbuffer *buffer)
  80 {
  81         if (buffer->orig_buffer != NULL)
  82                 free(buffer->orig_buffer);
  83         free(buffer);
  84 }
  85
  86 /*
  87  * This is a destructive add.  The data from one buffer moves into
  88  * the other buffer.
  89  */
  90
  91 #define SWAP(x,y) do { \
  92         (x)->buffer = (y)->buffer; \
  93         (x)->orig_buffer = (y)->orig_buffer; \
  94         (x)->misalign = (y)->misalign; \
  95         (x)->totallen = (y)->totallen; \
  96         (x)->off = (y)->off; \
  97 } while (0)
  98
  99 int
 100 evbuffer_add_buffer(struct evbuffer *outbuf, struct evbuffer *inbuf)
 101 {
 102         int res;
 103
 104         /* Short cut for better performance */
 105         if (outbuf->off == 0) {
 106                 struct evbuffer tmp;
 107                 size_t oldoff = inbuf->off;
 108
 109                 /* Swap them directly */
 110                 SWAP(&tmp, outbuf);
 111                 SWAP(outbuf, inbuf);
 112                 SWAP(inbuf, &tmp);
 113
 114                 /*
 115                  * Optimization comes with a price; we need to notify the
 116                  * buffer if necessary of the changes. oldoff is the amount
 117                  * of data that we transfered from inbuf to outbuf
 118                  */
 119                 if (inbuf->off != oldoff && inbuf->cb != NULL)
 120                         (*inbuf->cb)(inbuf, oldoff, inbuf->off, inbuf->cbarg);
 121                 if (oldoff && outbuf->cb != NULL)
 122                         (*outbuf->cb)(outbuf, 0, oldoff, outbuf->cbarg);
 123
 124                 return (0);
 125         }
 126
 127         res = evbuffer_add(outbuf, inbuf->buffer, inbuf->off);
 128         if (res == 0) {
 129                 /* We drain the input buffer on success */
 130                 evbuffer_drain(inbuf, inbuf->off);
 131         }
 132
 133         return (res);
 134 }
 135
 136 int
 137 evbuffer_add_vprintf(struct evbuffer *buf, const char *fmt, va_list ap)
 138 {
 139         char *buffer;
 140         size_t space;
 141         size_t oldoff = buf->off;
 142         int sz;
 143         va_list aq;
 144
 145         /* make sure that at least some space is available */
 146         evbuffer_expand(buf, 64);
 147         for (;;) {
 148                 size_t used = buf->misalign + buf->off;
 149                 buffer = (char *)buf->buffer + buf->off;
 150                 assert(buf->totallen >= used);
 151                 space = buf->totallen - used;
 152
 153 #ifndef va_copy
 154 #define va_copy(dst, src)       memcpy(&(dst), &(src), sizeof(va_list))
 155 #endif
 156                 va_copy(aq, ap);
 157
 158                 sz = evutil_vsnprintf(buffer, space, fmt, aq);
 159
 160                 va_end(aq);
 161
 162                 if (sz < 0)
 163                         return (-1);
 164                 if ((size_t)sz < space) {
 165                         buf->off += sz;
 166                         if (buf->cb != NULL)
 167                                 (*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
 168                         return (sz);
 169                 }
 170                 if (evbuffer_expand(buf, sz + 1) == -1)
 171                         return (-1);
 172
 173         }
 174         /* NOTREACHED */
 175 }
 176
 177 int
 178 evbuffer_add_printf(struct evbuffer *buf, const char *fmt, ...)
 179 {
 180         int res = -1;
 181         va_list ap;
 182
 183         va_start(ap, fmt);
 184         res = evbuffer_add_vprintf(buf, fmt, ap);
 185         va_end(ap);
 186
 187         return (res);
 188 }
 189
 190 /* Reads data from an event buffer and drains the bytes read */
 191
 192 int
 193 evbuffer_remove(struct evbuffer *buf, void *data, size_t datlen)
 194 {
 195         size_t nread = datlen;
 196         if (nread >= buf->off)
 197                 nread = buf->off;
 198
 199         memcpy(data, buf->buffer, nread);
 200         evbuffer_drain(buf, nread);
 201
 202         return (nread);
 203 }
 204
 205 /*
 206  * Reads a line terminated by either '\r\n', '\n\r' or '\r' or '\n'.
 207  * The returned buffer needs to be freed by the called.
 208  */
 209
 210 char *
 211 evbuffer_readline(struct evbuffer *buffer)
 212 {
 213         u_char *data = EVBUFFER_DATA(buffer);
 214         size_t len = EVBUFFER_LENGTH(buffer);
 215         char *line;
 216         unsigned int i;
 217
 218         for (i = 0; i < len; i++) {
 219                 if (data[i] == '\r' || data[i] == '\n')
 220                         break;
 221         }
 222
 223         if (i == len)
 224                 return (NULL);
 225
 226         if ((line = malloc(i + 1)) == NULL) {
 227                 fprintf(stderr, "%s: out of memory\n", __func__);
 228                 return (NULL);
 229         }
 230
 231         memcpy(line, data, i);
 232         line[i] = '\0';
 233
 234         /*
 235          * Some protocols terminate a line with '\r\n', so check for
 236          * that, too.
 237          */
 238         if ( i < len - 1 ) {
 239                 char fch = data[i], sch = data[i+1];
 240
 241                 /* Drain one more character if needed */
 242                 if ( (sch == '\r' || sch == '\n') && sch != fch )
 243                         i += 1;
 244         }
 245
 246         evbuffer_drain(buffer, i + 1);
 247
 248         return (line);
 249 }
 250
 251 /* Adds data to an event buffer */
 252
 253 static void
 254 evbuffer_align(struct evbuffer *buf)
 255 {
 256         memmove(buf->orig_buffer, buf->buffer, buf->off);
 257         buf->buffer = buf->orig_buffer;
 258         buf->misalign = 0;
 259 }
 260
 261 /* Expands the available space in the event buffer to at least datlen */
 262
 263 int
 264 evbuffer_expand(struct evbuffer *buf, size_t datlen)
 265 {
 266         size_t need = buf->misalign + buf->off + datlen;
 267
 268         /* If we can fit all the data, then we don't have to do anything */
 269         if (buf->totallen >= need)
 270                 return (0);
 271
 272         /*
 273          * If the misalignment fulfills our data needs, we just force an
 274          * alignment to happen.  Afterwards, we have enough space.
 275          */
 276         if (buf->misalign >= datlen) {
 277                 evbuffer_align(buf);
 278         } else {
 279                 void *newbuf;
 280                 size_t length = buf->totallen;
 281
 282                 if (length < 256)
 283                         length = 256;
 284                 while (length < need)
 285                         length <<= 1;
 286
 287                 if (buf->orig_buffer != buf->buffer)
 288                         evbuffer_align(buf);
 289                 if ((newbuf = realloc(buf->buffer, length)) == NULL)
 290                         return (-1);
 291
 292                 buf->orig_buffer = buf->buffer = newbuf;
 293                 buf->totallen = length;
 294         }
 295
 296         return (0);
 297 }
 298
 299 int
 300 evbuffer_add(struct evbuffer *buf, const void *data, size_t datlen)
 301 {
 302         size_t need = buf->misalign + buf->off + datlen;
 303         size_t oldoff = buf->off;
 304
 305         if (buf->totallen < need) {
 306                 if (evbuffer_expand(buf, datlen) == -1)
 307                         return (-1);
 308         }
 309
 310         memcpy(buf->buffer + buf->off, data, datlen);
 311         buf->off += datlen;
 312
 313         if (datlen && buf->cb != NULL)
 314                 (*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
 315
 316         return (0);
 317 }
 318
 319 void
 320 evbuffer_drain(struct evbuffer *buf, size_t len)
 321 {
 322         size_t oldoff = buf->off;
 323
 324         if (len >= buf->off) {
 325                 buf->off = 0;
 326                 buf->buffer = buf->orig_buffer;
 327                 buf->misalign = 0;
 328                 goto done;
 329         }
 330
 331         buf->buffer += len;
 332         buf->misalign += len;
 333
 334         buf->off -= len;
 335
 336  done:
 337         /* Tell someone about changes in this buffer */
 338         if (buf->off != oldoff && buf->cb != NULL)
 339                 (*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
 340
 341 }
 342
 343 /*
 344  * Reads data from a file descriptor into a buffer.
 345  */
 346
 347 #define EVBUFFER_MAX_READ       4096
 348
 349 int
 350 evbuffer_read(struct evbuffer *buf, int fd, int howmuch)
 351 {
 352         u_char *p;
 353         size_t oldoff = buf->off;
 354         int n = EVBUFFER_MAX_READ;
 355
 356 #if defined(FIONREAD)
 357 #ifdef WIN32
 358         long lng = n;
 359         if (ioctlsocket(fd, FIONREAD, &lng) == -1 || (n=lng) <= 0) {
 360 #else
 361         if (ioctl(fd, FIONREAD, &n) == -1 || n <= 0) {
 362 #endif
 363                 n = EVBUFFER_MAX_READ;
 364         } else if (n > EVBUFFER_MAX_READ && n > howmuch) {
 365                 /*
 366                  * It's possible that a lot of data is available for
 367                  * reading.  We do not want to exhaust resources
 368                  * before the reader has a chance to do something
 369                  * about it.  If the reader does not tell us how much
 370                  * data we should read, we artifically limit it.
 371                  */
 372                 if ((size_t)n > buf->totallen << 2)
 373                         n = buf->totallen << 2;
 374                 if (n < EVBUFFER_MAX_READ)
 375                         n = EVBUFFER_MAX_READ;
 376         }
 377 #endif
 378         if (howmuch < 0 || howmuch > n)
 379                 howmuch = n;
 380
 381         /* If we don't have FIONREAD, we might waste some space here */
 382         if (evbuffer_expand(buf, howmuch) == -1)
 383                 return (-1);
 384
 385         /* We can append new data at this point */
 386         p = buf->buffer + buf->off;
 387
 388 #ifndef WIN32
 389         n = read(fd, p, howmuch);
 390 #else
 391         n = recv(fd, p, howmuch, 0);
 392 #endif
 393         if (n == -1)
 394                 return (-1);
 395         if (n == 0)
 396                 return (0);
 397
 398         buf->off += n;
 399
 400         /* Tell someone about changes in this buffer */
 401         if (buf->off != oldoff && buf->cb != NULL)
 402                 (*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
 403
 404         return (n);
 405 }
 406
 407 int
 408 evbuffer_write(struct evbuffer *buffer, int fd)
 409 {
 410         int n;
 411
 412 #ifndef WIN32
 413         n = write(fd, buffer->buffer, buffer->off);
 414 #else
 415         n = send(fd, buffer->buffer, buffer->off, 0);
 416 #endif
 417         if (n == -1)
 418                 return (-1);
 419         if (n == 0)
 420                 return (0);
 421         evbuffer_drain(buffer, n);
 422
 423         return (n);
 424 }
 425
 426 u_char *
 427 evbuffer_find(struct evbuffer *buffer, const u_char *what, size_t len)
 428 {
 429         u_char *search = buffer->buffer, *end = search + buffer->off;
 430         u_char *p;
 431
 432         while (search < end &&
 433             (p = memchr(search, *what, end - search)) != NULL) {
 434                 if (p + len > end)
 435                         break;
 436                 if (memcmp(p, what, len) == 0)
 437                         return (p);
 438                 search = p + 1;
 439         }
 440
 441         return (NULL);
 442 }
 443
 444 void evbuffer_setcb(struct evbuffer *buffer,
 445     void (*cb)(struct evbuffer *, size_t, size_t, void *),
 446     void *cbarg)
 447 {
 448         buffer->cb = cb;
 449         buffer->cbarg = cbarg;
 450 }