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 response end 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 int write_packetized_from_fd_no_flush(int fd_in, int fd_out)
 256 {
 257         char *buf = xmalloc(LARGE_PACKET_DATA_MAX);
 258         int err = 0;
 259         ssize_t bytes_to_write;
 260
 261         while (!err) {
 262                 bytes_to_write = xread(fd_in, buf, LARGE_PACKET_DATA_MAX);
 263                 if (bytes_to_write < 0) {
 264                         free(buf);
 265                         return COPY_READ_ERROR;
 266                 }
 267                 if (bytes_to_write == 0)
 268                         break;
 269                 err = packet_write_gently(fd_out, buf, bytes_to_write);
 270         }
 271         free(buf);
 272         return err;
 273 }
 274
 275 int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out)
 276 {
 277         int err = 0;
 278         size_t bytes_written = 0;
 279         size_t bytes_to_write;
 280
 281         while (!err) {
 282                 if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
 283                         bytes_to_write = LARGE_PACKET_DATA_MAX;
 284                 else
 285                         bytes_to_write = len - bytes_written;
 286                 if (bytes_to_write == 0)
 287                         break;
 288                 err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
 289                 bytes_written += bytes_to_write;
 290         }
 291         return err;
 292 }
 293
 294 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 295                            void *dst, unsigned size, int options)
 296 {
 297         ssize_t ret;
 298
 299         if (fd >= 0 && src_buf && *src_buf)
 300                 BUG("multiple sources given to packet_read");
 301
 302         /* Read up to "size" bytes from our source, whatever it is. */
 303         if (src_buf && *src_buf) {
 304                 ret = size < *src_size ? size : *src_size;
 305                 memcpy(dst, *src_buf, ret);
 306                 *src_buf += ret;
 307                 *src_size -= ret;
 308         } else {
 309                 ret = read_in_full(fd, dst, size);
 310                 if (ret < 0) {
 311                         if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 312                                 return error_errno(_("read error"));
 313                         die_errno(_("read error"));
 314                 }
 315         }
 316
 317         /* And complain if we didn't get enough bytes to satisfy the read. */
 318         if (ret != size) {
 319                 if (options & PACKET_READ_GENTLE_ON_EOF)
 320                         return -1;
 321
 322                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 323                         return error(_("the remote end hung up unexpectedly"));
 324                 die(_("the remote end hung up unexpectedly"));
 325         }
 326
 327         return ret;
 328 }
 329
 330 int packet_length(const char lenbuf_hex[4])
 331 {
 332         int val = hex2chr(lenbuf_hex);
 333         return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
 334 }
 335
 336 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 337                                                 size_t *src_len, char *buffer,
 338                                                 unsigned size, int *pktlen,
 339                                                 int options)
 340 {
 341         int len;
 342         char linelen[4];
 343
 344         if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
 345                 *pktlen = -1;
 346                 return PACKET_READ_EOF;
 347         }
 348
 349         len = packet_length(linelen);
 350
 351         if (len < 0) {
 352                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 353                         return error(_("protocol error: bad line length "
 354                                        "character: %.4s"), linelen);
 355                 die(_("protocol error: bad line length character: %.4s"), linelen);
 356         } else if (!len) {
 357                 packet_trace("0000", 4, 0);
 358                 *pktlen = 0;
 359                 return PACKET_READ_FLUSH;
 360         } else if (len == 1) {
 361                 packet_trace("0001", 4, 0);
 362                 *pktlen = 0;
 363                 return PACKET_READ_DELIM;
 364         } else if (len == 2) {
 365                 packet_trace("0002", 4, 0);
 366                 *pktlen = 0;
 367                 return PACKET_READ_RESPONSE_END;
 368         } else if (len < 4) {
 369                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 370                         return error(_("protocol error: bad line length %d"),
 371                                      len);
 372                 die(_("protocol error: bad line length %d"), len);
 373         }
 374
 375         len -= 4;
 376         if ((unsigned)len >= size) {
 377                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 378                         return error(_("protocol error: bad line length %d"),
 379                                      len);
 380                 die(_("protocol error: bad line length %d"), len);
 381         }
 382
 383         if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
 384                 *pktlen = -1;
 385                 return PACKET_READ_EOF;
 386         }
 387
 388         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 389             len && buffer[len-1] == '\n')
 390                 len--;
 391
 392         buffer[len] = 0;
 393         packet_trace(buffer, len, 0);
 394
 395         if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
 396             starts_with(buffer, "ERR "))
 397                 die(_("remote error: %s"), buffer + 4);
 398
 399         *pktlen = len;
 400         return PACKET_READ_NORMAL;
 401 }
 402
 403 int packet_read(int fd, char **src_buffer, size_t *src_len,
 404                 char *buffer, unsigned size, int options)
 405 {
 406         int pktlen = -1;
 407
 408         packet_read_with_status(fd, src_buffer, src_len, buffer, size,
 409                                 &pktlen, options);
 410
 411         return pktlen;
 412 }
 413
 414 static char *packet_read_line_generic(int fd,
 415                                       char **src, size_t *src_len,
 416                                       int *dst_len)
 417 {
 418         int len = packet_read(fd, src, src_len,
 419                               packet_buffer, sizeof(packet_buffer),
 420                               PACKET_READ_CHOMP_NEWLINE);
 421         if (dst_len)
 422                 *dst_len = len;
 423         return (len > 0) ? packet_buffer : NULL;
 424 }
 425
 426 char *packet_read_line(int fd, int *len_p)
 427 {
 428         return packet_read_line_generic(fd, NULL, NULL, len_p);
 429 }
 430
 431 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
 432 {
 433         int len = packet_read(fd, NULL, NULL,
 434                               packet_buffer, sizeof(packet_buffer),
 435                               PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
 436         if (dst_len)
 437                 *dst_len = len;
 438         if (dst_line)
 439                 *dst_line = (len > 0) ? packet_buffer : NULL;
 440         return len;
 441 }
 442
 443 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 444 {
 445         return packet_read_line_generic(-1, src, src_len, dst_len);
 446 }
 447
 448 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options)
 449 {
 450         int packet_len;
 451
 452         size_t orig_len = sb_out->len;
 453         size_t orig_alloc = sb_out->alloc;
 454
 455         for (;;) {
 456                 strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
 457                 packet_len = packet_read(fd_in, NULL, NULL,
 458                         /* strbuf_grow() above always allocates one extra byte to
 459                          * store a '\0' at the end of the string. packet_read()
 460                          * writes a '\0' extra byte at the end, too. Let it know
 461                          * that there is already room for the extra byte.
 462                          */
 463                         sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
 464                         options);
 465                 if (packet_len <= 0)
 466                         break;
 467                 sb_out->len += packet_len;
 468         }
 469
 470         if (packet_len < 0) {
 471                 if (orig_alloc == 0)
 472                         strbuf_release(sb_out);
 473                 else
 474                         strbuf_setlen(sb_out, orig_len);
 475                 return packet_len;
 476         }
 477         return sb_out->len - orig_len;
 478 }
 479
 480 int recv_sideband(const char *me, int in_stream, int out)
 481 {
 482         char buf[LARGE_PACKET_MAX + 1];
 483         int len;
 484         struct strbuf scratch = STRBUF_INIT;
 485         enum sideband_type sideband_type;
 486
 487         while (1) {
 488                 int status = packet_read_with_status(in_stream, NULL, NULL,
 489                                                      buf, LARGE_PACKET_MAX,
 490                                                      &len,
 491                                                      PACKET_READ_GENTLE_ON_EOF);
 492                 if (!demultiplex_sideband(me, status, buf, len, 0, &scratch,
 493                                           &sideband_type))
 494                         continue;
 495                 switch (sideband_type) {
 496                 case SIDEBAND_PRIMARY:
 497                         write_or_die(out, buf + 1, len - 1);
 498                         break;
 499                 default: /* errors: message already written */
 500                         if (scratch.len > 0)
 501                                 BUG("unhandled incomplete sideband: '%s'",
 502                                     scratch.buf);
 503                         return sideband_type;
 504                 }
 505         }
 506 }
 507
 508 /* Packet Reader Functions */
 509 void packet_reader_init(struct packet_reader *reader, int fd,
 510                         char *src_buffer, size_t src_len,
 511                         int options)
 512 {
 513         memset(reader, 0, sizeof(*reader));
 514
 515         reader->fd = fd;
 516         reader->src_buffer = src_buffer;
 517         reader->src_len = src_len;
 518         reader->buffer = packet_buffer;
 519         reader->buffer_size = sizeof(packet_buffer);
 520         reader->options = options;
 521         reader->me = "git";
 522         reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 523 }
 524
 525 enum packet_read_status packet_reader_read(struct packet_reader *reader)
 526 {
 527         struct strbuf scratch = STRBUF_INIT;
 528
 529         if (reader->line_peeked) {
 530                 reader->line_peeked = 0;
 531                 return reader->status;
 532         }
 533
 534         /*
 535          * Consume all progress packets until a primary payload packet is
 536          * received
 537          */
 538         while (1) {
 539                 enum sideband_type sideband_type;
 540                 reader->status = packet_read_with_status(reader->fd,
 541                                                          &reader->src_buffer,
 542                                                          &reader->src_len,
 543                                                          reader->buffer,
 544                                                          reader->buffer_size,
 545                                                          &reader->pktlen,
 546                                                          reader->options);
 547                 if (!reader->use_sideband)
 548                         break;
 549                 if (demultiplex_sideband(reader->me, reader->status,
 550                                          reader->buffer, reader->pktlen, 1,
 551                                          &scratch, &sideband_type))
 552                         break;
 553         }
 554
 555         if (reader->status == PACKET_READ_NORMAL)
 556                 /* Skip the sideband designator if sideband is used */
 557                 reader->line = reader->use_sideband ?
 558                         reader->buffer + 1 : reader->buffer;
 559         else
 560                 reader->line = NULL;
 561
 562         return reader->status;
 563 }
 564
 565 enum packet_read_status packet_reader_peek(struct packet_reader *reader)
 566 {
 567         /* Only allow peeking a single line */
 568         if (reader->line_peeked)
 569                 return reader->status;
 570
 571         /* Peek a line by reading it and setting peeked flag */
 572         packet_reader_read(reader);
 573         reader->line_peeked = 1;
 574         return reader->status;
 575 }
 576
 577 void packet_writer_init(struct packet_writer *writer, int dest_fd)
 578 {
 579         writer->dest_fd = dest_fd;
 580         writer->use_sideband = 0;
 581 }
 582
 583 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
 584 {
 585         va_list args;
 586
 587         va_start(args, fmt);
 588         packet_write_fmt_1(writer->dest_fd, 0,
 589                            writer->use_sideband ? "\001" : "", fmt, args);
 590         va_end(args);
 591 }
 592
 593 void packet_writer_error(struct packet_writer *writer, const char *fmt, ...)
 594 {
 595         va_list args;
 596
 597         va_start(args, fmt);
 598         packet_write_fmt_1(writer->dest_fd, 0,
 599                            writer->use_sideband ? "\003" : "ERR ", fmt, args);
 600         va_end(args);
 601 }
 602
 603 void packet_writer_delim(struct packet_writer *writer)
 604 {
 605         packet_delim(writer->dest_fd);
 606 }
 607
 608 void packet_writer_flush(struct packet_writer *writer)
 609 {
 610         packet_flush(writer->dest_fd);
 611 }