pkt-line.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3 #include "run-command.h"
   4
   5 char packet_buffer[LARGE_PACKET_MAX];
   6 static const char *packet_trace_prefix = "git";
   7 static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
   8 static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);
   9
  10 void packet_trace_identity(const char *prog)
  11 {
  12         packet_trace_prefix = xstrdup(prog);
  13 }
  14
  15 static const char *get_trace_prefix(void)
  16 {
  17         return in_async() ? "sideband" : packet_trace_prefix;
  18 }
  19
  20 static int packet_trace_pack(const char *buf, unsigned int len, int sideband)
  21 {
  22         if (!sideband) {
  23                 trace_verbatim(&trace_pack, buf, len);
  24                 return 1;
  25         } else if (len && *buf == '\1') {
  26                 trace_verbatim(&trace_pack, buf + 1, len - 1);
  27                 return 1;
  28         } else {
  29                 /* it's another non-pack sideband */
  30                 return 0;
  31         }
  32 }
  33
  34 static void packet_trace(const char *buf, unsigned int len, int write)
  35 {
  36         int i;
  37         struct strbuf out;
  38         static int in_pack, sideband;
  39
  40         if (!trace_want(&trace_packet) && !trace_want(&trace_pack))
  41                 return;
  42
  43         if (in_pack) {
  44                 if (packet_trace_pack(buf, len, sideband))
  45                         return;
  46         } else if (starts_with(buf, "PACK") || starts_with(buf, "\1PACK")) {
  47                 in_pack = 1;
  48                 sideband = *buf == '\1';
  49                 packet_trace_pack(buf, len, sideband);
  50
  51                 /*
  52                  * Make a note in the human-readable trace that the pack data
  53                  * started.
  54                  */
  55                 buf = "PACK ...";
  56                 len = strlen(buf);
  57         }
  58
  59         if (!trace_want(&trace_packet))
  60                 return;
  61
  62         /* +32 is just a guess for header + quoting */
  63         strbuf_init(&out, len+32);
  64
  65         strbuf_addf(&out, "packet: %12s%c ",
  66                     get_trace_prefix(), write ? '>' : '<');
  67
  68         /* XXX we should really handle printable utf8 */
  69         for (i = 0; i < len; i++) {
  70                 /* suppress newlines */
  71                 if (buf[i] == '\n')
  72                         continue;
  73                 if (buf[i] >= 0x20 && buf[i] <= 0x7e)
  74                         strbuf_addch(&out, buf[i]);
  75                 else
  76                         strbuf_addf(&out, "\\%o", buf[i]);
  77         }
  78
  79         strbuf_addch(&out, '\n');
  80         trace_strbuf(&trace_packet, &out);
  81         strbuf_release(&out);
  82 }
  83
  84 /*
  85  * If we buffered things up above (we don't, but we should),
  86  * we'd flush it here
  87  */
  88 void packet_flush(int fd)
  89 {
  90         packet_trace("0000", 4, 1);
  91         if (write_in_full(fd, "0000", 4) < 0)
  92                 die_errno(_("unable to write flush packet"));
  93 }
  94
  95 void packet_delim(int fd)
  96 {
  97         packet_trace("0001", 4, 1);
  98         if (write_in_full(fd, "0001", 4) < 0)
  99                 die_errno(_("unable to write delim packet"));
 100 }
 101
 102 void packet_response_end(int fd)
 103 {
 104         packet_trace("0002", 4, 1);
 105         if (write_in_full(fd, "0002", 4) < 0)
 106                 die_errno(_("unable to write stateless separator packet"));
 107 }
 108
 109 int packet_flush_gently(int fd)
 110 {
 111         packet_trace("0000", 4, 1);
 112         if (write_in_full(fd, "0000", 4) < 0)
 113                 return error(_("flush packet write failed"));
 114         return 0;
 115 }
 116
 117 void packet_buf_flush(struct strbuf *buf)
 118 {
 119         packet_trace("0000", 4, 1);
 120         strbuf_add(buf, "0000", 4);
 121 }
 122
 123 void packet_buf_delim(struct strbuf *buf)
 124 {
 125         packet_trace("0001", 4, 1);
 126         strbuf_add(buf, "0001", 4);
 127 }
 128
 129 void set_packet_header(char *buf, int size)
 130 {
 131         static char hexchar[] = "0123456789abcdef";
 132
 133         #define hex(a) (hexchar[(a) & 15])
 134         buf[0] = hex(size >> 12);
 135         buf[1] = hex(size >> 8);
 136         buf[2] = hex(size >> 4);
 137         buf[3] = hex(size);
 138         #undef hex
 139 }
 140
 141 static void format_packet(struct strbuf *out, const char *prefix,
 142                           const char *fmt, va_list args)
 143 {
 144         size_t orig_len, n;
 145
 146         orig_len = out->len;
 147         strbuf_addstr(out, "0000");
 148         strbuf_addstr(out, prefix);
 149         strbuf_vaddf(out, fmt, args);
 150         n = out->len - orig_len;
 151
 152         if (n > LARGE_PACKET_MAX)
 153                 die(_("protocol error: impossibly long line"));
 154
 155         set_packet_header(&out->buf[orig_len], n);
 156         packet_trace(out->buf + orig_len + 4, n - 4, 1);
 157 }
 158
 159 static int packet_write_fmt_1(int fd, int gently, const char *prefix,
 160                               const char *fmt, va_list args)
 161 {
 162         static struct strbuf buf = STRBUF_INIT;
 163
 164         strbuf_reset(&buf);
 165         format_packet(&buf, prefix, fmt, args);
 166         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 167                 if (!gently) {
 168                         check_pipe(errno);
 169                         die_errno(_("packet write with format failed"));
 170                 }
 171                 return error(_("packet write with format failed"));
 172         }
 173
 174         return 0;
 175 }
 176
 177 void packet_write_fmt(int fd, const char *fmt, ...)
 178 {
 179         va_list args;
 180
 181         va_start(args, fmt);
 182         packet_write_fmt_1(fd, 0, "", fmt, args);
 183         va_end(args);
 184 }
 185
 186 int packet_write_fmt_gently(int fd, const char *fmt, ...)
 187 {
 188         int status;
 189         va_list args;
 190
 191         va_start(args, fmt);
 192         status = packet_write_fmt_1(fd, 1, "", fmt, args);
 193         va_end(args);
 194         return status;
 195 }
 196
 197 static int do_packet_write(const int fd_out, const char *buf, size_t size,
 198                            struct strbuf *err)
 199 {
 200         char header[4];
 201         size_t packet_size;
 202
 203         if (size > LARGE_PACKET_DATA_MAX) {
 204                 strbuf_addstr(err, _("packet write failed - data exceeds max packet size"));
 205                 return -1;
 206         }
 207
 208         packet_trace(buf, size, 1);
 209         packet_size = size + 4;
 210
 211         set_packet_header(header, packet_size);
 212
 213         /*
 214          * Write the header and the buffer in 2 parts so that we do
 215          * not need to allocate a buffer or rely on a static buffer.
 216          * This also avoids putting a large buffer on the stack which
 217          * might have multi-threading issues.
 218          */
 219
 220         if (write_in_full(fd_out, header, 4) < 0 ||
 221             write_in_full(fd_out, buf, size) < 0) {
 222                 strbuf_addf(err, _("packet write failed: %s"), strerror(errno));
 223                 return -1;
 224         }
 225         return 0;
 226 }
 227
 228 static int packet_write_gently(const int fd_out, const char *buf, size_t size)
 229 {
 230         struct strbuf err = STRBUF_INIT;
 231         if (do_packet_write(fd_out, buf, size, &err)) {
 232                 error("%s", err.buf);
 233                 strbuf_release(&err);
 234                 return -1;
 235         }
 236         return 0;
 237 }
 238
 239 void packet_write(int fd_out, const char *buf, size_t size)
 240 {
 241         struct strbuf err = STRBUF_INIT;
 242         if (do_packet_write(fd_out, buf, size, &err))
 243                 die("%s", err.buf);
 244 }
 245
 246 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 247 {
 248         va_list args;
 249
 250         va_start(args, fmt);
 251         format_packet(buf, "", fmt, args);
 252         va_end(args);
 253 }
 254
 255 void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
 256 {
 257         size_t orig_len, n;
 258
 259         orig_len = buf->len;
 260         strbuf_addstr(buf, "0000");
 261         strbuf_add(buf, data, len);
 262         n = buf->len - orig_len;
 263
 264         if (n > LARGE_PACKET_MAX)
 265                 die(_("protocol error: impossibly long line"));
 266
 267         set_packet_header(&buf->buf[orig_len], n);
 268         packet_trace(data, len, 1);
 269 }
 270
 271 int write_packetized_from_fd_no_flush(int fd_in, int fd_out)
 272 {
 273         char *buf = xmalloc(LARGE_PACKET_DATA_MAX);
 274         int err = 0;
 275         ssize_t bytes_to_write;
 276
 277         while (!err) {
 278                 bytes_to_write = xread(fd_in, buf, LARGE_PACKET_DATA_MAX);
 279                 if (bytes_to_write < 0) {
 280                         free(buf);
 281                         return COPY_READ_ERROR;
 282                 }
 283                 if (bytes_to_write == 0)
 284                         break;
 285                 err = packet_write_gently(fd_out, buf, bytes_to_write);
 286         }
 287         free(buf);
 288         return err;
 289 }
 290
 291 int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out)
 292 {
 293         int err = 0;
 294         size_t bytes_written = 0;
 295         size_t bytes_to_write;
 296
 297         while (!err) {
 298                 if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
 299                         bytes_to_write = LARGE_PACKET_DATA_MAX;
 300                 else
 301                         bytes_to_write = len - bytes_written;
 302                 if (bytes_to_write == 0)
 303                         break;
 304                 err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
 305                 bytes_written += bytes_to_write;
 306         }
 307         return err;
 308 }
 309
 310 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 311                            void *dst, unsigned size, int options)
 312 {
 313         ssize_t ret;
 314
 315         if (fd >= 0 && src_buf && *src_buf)
 316                 BUG("multiple sources given to packet_read");
 317
 318         /* Read up to "size" bytes from our source, whatever it is. */
 319         if (src_buf && *src_buf) {
 320                 ret = size < *src_size ? size : *src_size;
 321                 memcpy(dst, *src_buf, ret);
 322                 *src_buf += ret;
 323                 *src_size -= ret;
 324         } else {
 325                 ret = read_in_full(fd, dst, size);
 326                 if (ret < 0) {
 327                         if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 328                                 return error_errno(_("read error"));
 329                         die_errno(_("read error"));
 330                 }
 331         }
 332
 333         /* And complain if we didn't get enough bytes to satisfy the read. */
 334         if (ret != size) {
 335                 if (options & PACKET_READ_GENTLE_ON_EOF)
 336                         return -1;
 337
 338                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 339                         return error(_("the remote end hung up unexpectedly"));
 340                 die(_("the remote end hung up unexpectedly"));
 341         }
 342
 343         return ret;
 344 }
 345
 346 int packet_length(const char lenbuf_hex[4])
 347 {
 348         int val = hex2chr(lenbuf_hex);
 349         return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
 350 }
 351
 352 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 353                                                 size_t *src_len, char *buffer,
 354                                                 unsigned size, int *pktlen,
 355                                                 int options)
 356 {
 357         int len;
 358         char linelen[4];
 359
 360         if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
 361                 *pktlen = -1;
 362                 return PACKET_READ_EOF;
 363         }
 364
 365         len = packet_length(linelen);
 366
 367         if (len < 0) {
 368                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 369                         return error(_("protocol error: bad line length "
 370                                        "character: %.4s"), linelen);
 371                 die(_("protocol error: bad line length character: %.4s"), linelen);
 372         } else if (!len) {
 373                 packet_trace("0000", 4, 0);
 374                 *pktlen = 0;
 375                 return PACKET_READ_FLUSH;
 376         } else if (len == 1) {
 377                 packet_trace("0001", 4, 0);
 378                 *pktlen = 0;
 379                 return PACKET_READ_DELIM;
 380         } else if (len == 2) {
 381                 packet_trace("0002", 4, 0);
 382                 *pktlen = 0;
 383                 return PACKET_READ_RESPONSE_END;
 384         } else if (len < 4) {
 385                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 386                         return error(_("protocol error: bad line length %d"),
 387                                      len);
 388                 die(_("protocol error: bad line length %d"), len);
 389         }
 390
 391         len -= 4;
 392         if ((unsigned)len >= size) {
 393                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 394                         return error(_("protocol error: bad line length %d"),
 395                                      len);
 396                 die(_("protocol error: bad line length %d"), len);
 397         }
 398
 399         if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
 400                 *pktlen = -1;
 401                 return PACKET_READ_EOF;
 402         }
 403
 404         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 405             len && buffer[len-1] == '\n')
 406                 len--;
 407
 408         buffer[len] = 0;
 409         packet_trace(buffer, len, 0);
 410
 411         if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
 412             starts_with(buffer, "ERR "))
 413                 die(_("remote error: %s"), buffer + 4);
 414
 415         *pktlen = len;
 416         return PACKET_READ_NORMAL;
 417 }
 418
 419 int packet_read(int fd, char **src_buffer, size_t *src_len,
 420                 char *buffer, unsigned size, int options)
 421 {
 422         int pktlen = -1;
 423
 424         packet_read_with_status(fd, src_buffer, src_len, buffer, size,
 425                                 &pktlen, options);
 426
 427         return pktlen;
 428 }
 429
 430 static char *packet_read_line_generic(int fd,
 431                                       char **src, size_t *src_len,
 432                                       int *dst_len)
 433 {
 434         int len = packet_read(fd, src, src_len,
 435                               packet_buffer, sizeof(packet_buffer),
 436                               PACKET_READ_CHOMP_NEWLINE);
 437         if (dst_len)
 438                 *dst_len = len;
 439         return (len > 0) ? packet_buffer : NULL;
 440 }
 441
 442 char *packet_read_line(int fd, int *len_p)
 443 {
 444         return packet_read_line_generic(fd, NULL, NULL, len_p);
 445 }
 446
 447 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
 448 {
 449         int len = packet_read(fd, NULL, NULL,
 450                               packet_buffer, sizeof(packet_buffer),
 451                               PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
 452         if (dst_len)
 453                 *dst_len = len;
 454         if (dst_line)
 455                 *dst_line = (len > 0) ? packet_buffer : NULL;
 456         return len;
 457 }
 458
 459 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 460 {
 461         return packet_read_line_generic(-1, src, src_len, dst_len);
 462 }
 463
 464 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options)
 465 {
 466         int packet_len;
 467
 468         size_t orig_len = sb_out->len;
 469         size_t orig_alloc = sb_out->alloc;
 470
 471         for (;;) {
 472                 strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
 473                 packet_len = packet_read(fd_in, NULL, NULL,
 474                         /* strbuf_grow() above always allocates one extra byte to
 475                          * store a '\0' at the end of the string. packet_read()
 476                          * writes a '\0' extra byte at the end, too. Let it know
 477                          * that there is already room for the extra byte.
 478                          */
 479                         sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
 480                         options);
 481                 if (packet_len <= 0)
 482                         break;
 483                 sb_out->len += packet_len;
 484         }
 485
 486         if (packet_len < 0) {
 487                 if (orig_alloc == 0)
 488                         strbuf_release(sb_out);
 489                 else
 490                         strbuf_setlen(sb_out, orig_len);
 491                 return packet_len;
 492         }
 493         return sb_out->len - orig_len;
 494 }
 495
 496 int recv_sideband(const char *me, int in_stream, int out)
 497 {
 498         char buf[LARGE_PACKET_MAX + 1];
 499         int len;
 500         struct strbuf scratch = STRBUF_INIT;
 501         enum sideband_type sideband_type;
 502
 503         while (1) {
 504                 int status = packet_read_with_status(in_stream, NULL, NULL,
 505                                                      buf, LARGE_PACKET_MAX,
 506                                                      &len,
 507                                                      PACKET_READ_GENTLE_ON_EOF);
 508                 if (!demultiplex_sideband(me, status, buf, len, 0, &scratch,
 509                                           &sideband_type))
 510                         continue;
 511                 switch (sideband_type) {
 512                 case SIDEBAND_PRIMARY:
 513                         write_or_die(out, buf + 1, len - 1);
 514                         break;
 515                 default: /* errors: message already written */
 516                         if (scratch.len > 0)
 517                                 BUG("unhandled incomplete sideband: '%s'",
 518                                     scratch.buf);
 519                         return sideband_type;
 520                 }
 521         }
 522 }
 523
 524 /* Packet Reader Functions */
 525 void packet_reader_init(struct packet_reader *reader, int fd,
 526                         char *src_buffer, size_t src_len,
 527                         int options)
 528 {
 529         memset(reader, 0, sizeof(*reader));
 530
 531         reader->fd = fd;
 532         reader->src_buffer = src_buffer;
 533         reader->src_len = src_len;
 534         reader->buffer = packet_buffer;
 535         reader->buffer_size = sizeof(packet_buffer);
 536         reader->options = options;
 537         reader->me = "git";
 538         reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 539 }
 540
 541 enum packet_read_status packet_reader_read(struct packet_reader *reader)
 542 {
 543         struct strbuf scratch = STRBUF_INIT;
 544
 545         if (reader->line_peeked) {
 546                 reader->line_peeked = 0;
 547                 return reader->status;
 548         }
 549
 550         /*
 551          * Consume all progress packets until a primary payload packet is
 552          * received
 553          */
 554         while (1) {
 555                 enum sideband_type sideband_type;
 556                 reader->status = packet_read_with_status(reader->fd,
 557                                                          &reader->src_buffer,
 558                                                          &reader->src_len,
 559                                                          reader->buffer,
 560                                                          reader->buffer_size,
 561                                                          &reader->pktlen,
 562                                                          reader->options);
 563                 if (!reader->use_sideband)
 564                         break;
 565                 if (demultiplex_sideband(reader->me, reader->status,
 566                                          reader->buffer, reader->pktlen, 1,
 567                                          &scratch, &sideband_type))
 568                         break;
 569         }
 570
 571         if (reader->status == PACKET_READ_NORMAL)
 572                 /* Skip the sideband designator if sideband is used */
 573                 reader->line = reader->use_sideband ?
 574                         reader->buffer + 1 : reader->buffer;
 575         else
 576                 reader->line = NULL;
 577
 578         return reader->status;
 579 }
 580
 581 enum packet_read_status packet_reader_peek(struct packet_reader *reader)
 582 {
 583         /* Only allow peeking a single line */
 584         if (reader->line_peeked)
 585                 return reader->status;
 586
 587         /* Peek a line by reading it and setting peeked flag */
 588         packet_reader_read(reader);
 589         reader->line_peeked = 1;
 590         return reader->status;
 591 }
 592
 593 void packet_writer_init(struct packet_writer *writer, int dest_fd)
 594 {
 595         writer->dest_fd = dest_fd;
 596         writer->use_sideband = 0;
 597 }
 598
 599 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
 600 {
 601         va_list args;
 602
 603         va_start(args, fmt);
 604         packet_write_fmt_1(writer->dest_fd, 0,
 605                            writer->use_sideband ? "\001" : "", fmt, args);
 606         va_end(args);
 607 }
 608
 609 void packet_writer_error(struct packet_writer *writer, const char *fmt, ...)
 610 {
 611         va_list args;
 612
 613         va_start(args, fmt);
 614         packet_write_fmt_1(writer->dest_fd, 0,
 615                            writer->use_sideband ? "\003" : "ERR ", fmt, args);
 616         va_end(args);
 617 }
 618
 619 void packet_writer_delim(struct packet_writer *writer)
 620 {
 621         packet_delim(writer->dest_fd);
 622 }
 623
 624 void packet_writer_flush(struct packet_writer *writer)
 625 {
 626         packet_flush(writer->dest_fd);
 627 }