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 packet_write_gently(const int fd_out, const char *buf, size_t size)
 198 {
 199         char header[4];
 200         size_t packet_size;
 201
 202         if (size > LARGE_PACKET_DATA_MAX)
 203                 return error(_("packet write failed - data exceeds max packet size"));
 204
 205         packet_trace(buf, size, 1);
 206         packet_size = size + 4;
 207
 208         set_packet_header(header, packet_size);
 209
 210         /*
 211          * Write the header and the buffer in 2 parts so that we do
 212          * not need to allocate a buffer or rely on a static buffer.
 213          * This also avoids putting a large buffer on the stack which
 214          * might have multi-threading issues.
 215          */
 216
 217         if (write_in_full(fd_out, header, 4) < 0 ||
 218             write_in_full(fd_out, buf, size) < 0)
 219                 return error(_("packet write failed"));
 220         return 0;
 221 }
 222
 223 void packet_write(int fd_out, const char *buf, size_t size)
 224 {
 225         if (packet_write_gently(fd_out, buf, size))
 226                 die_errno(_("packet write failed"));
 227 }
 228
 229 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 230 {
 231         va_list args;
 232
 233         va_start(args, fmt);
 234         format_packet(buf, "", fmt, args);
 235         va_end(args);
 236 }
 237
 238 void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
 239 {
 240         size_t orig_len, n;
 241
 242         orig_len = buf->len;
 243         strbuf_addstr(buf, "0000");
 244         strbuf_add(buf, data, len);
 245         n = buf->len - orig_len;
 246
 247         if (n > LARGE_PACKET_MAX)
 248                 die(_("protocol error: impossibly long line"));
 249
 250         set_packet_header(&buf->buf[orig_len], n);
 251         packet_trace(data, len, 1);
 252 }
 253
 254 int write_packetized_from_fd_no_flush(int fd_in, int fd_out)
 255 {
 256         char *buf = xmalloc(LARGE_PACKET_DATA_MAX);
 257         int err = 0;
 258         ssize_t bytes_to_write;
 259
 260         while (!err) {
 261                 bytes_to_write = xread(fd_in, buf, LARGE_PACKET_DATA_MAX);
 262                 if (bytes_to_write < 0) {
 263                         free(buf);
 264                         return COPY_READ_ERROR;
 265                 }
 266                 if (bytes_to_write == 0)
 267                         break;
 268                 err = packet_write_gently(fd_out, buf, bytes_to_write);
 269         }
 270         free(buf);
 271         return err;
 272 }
 273
 274 int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out)
 275 {
 276         int err = 0;
 277         size_t bytes_written = 0;
 278         size_t bytes_to_write;
 279
 280         while (!err) {
 281                 if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
 282                         bytes_to_write = LARGE_PACKET_DATA_MAX;
 283                 else
 284                         bytes_to_write = len - bytes_written;
 285                 if (bytes_to_write == 0)
 286                         break;
 287                 err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
 288                 bytes_written += bytes_to_write;
 289         }
 290         return err;
 291 }
 292
 293 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 294                            void *dst, unsigned size, int options)
 295 {
 296         ssize_t ret;
 297
 298         if (fd >= 0 && src_buf && *src_buf)
 299                 BUG("multiple sources given to packet_read");
 300
 301         /* Read up to "size" bytes from our source, whatever it is. */
 302         if (src_buf && *src_buf) {
 303                 ret = size < *src_size ? size : *src_size;
 304                 memcpy(dst, *src_buf, ret);
 305                 *src_buf += ret;
 306                 *src_size -= ret;
 307         } else {
 308                 ret = read_in_full(fd, dst, size);
 309                 if (ret < 0) {
 310                         if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 311                                 return error_errno(_("read error"));
 312                         die_errno(_("read error"));
 313                 }
 314         }
 315
 316         /* And complain if we didn't get enough bytes to satisfy the read. */
 317         if (ret != size) {
 318                 if (options & PACKET_READ_GENTLE_ON_EOF)
 319                         return -1;
 320
 321                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 322                         return error(_("the remote end hung up unexpectedly"));
 323                 die(_("the remote end hung up unexpectedly"));
 324         }
 325
 326         return ret;
 327 }
 328
 329 int packet_length(const char lenbuf_hex[4])
 330 {
 331         int val = hex2chr(lenbuf_hex);
 332         return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
 333 }
 334
 335 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 336                                                 size_t *src_len, char *buffer,
 337                                                 unsigned size, int *pktlen,
 338                                                 int options)
 339 {
 340         int len;
 341         char linelen[4];
 342
 343         if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
 344                 *pktlen = -1;
 345                 return PACKET_READ_EOF;
 346         }
 347
 348         len = packet_length(linelen);
 349
 350         if (len < 0) {
 351                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 352                         return error(_("protocol error: bad line length "
 353                                        "character: %.4s"), linelen);
 354                 die(_("protocol error: bad line length character: %.4s"), linelen);
 355         } else if (!len) {
 356                 packet_trace("0000", 4, 0);
 357                 *pktlen = 0;
 358                 return PACKET_READ_FLUSH;
 359         } else if (len == 1) {
 360                 packet_trace("0001", 4, 0);
 361                 *pktlen = 0;
 362                 return PACKET_READ_DELIM;
 363         } else if (len == 2) {
 364                 packet_trace("0002", 4, 0);
 365                 *pktlen = 0;
 366                 return PACKET_READ_RESPONSE_END;
 367         } else if (len < 4) {
 368                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 369                         return error(_("protocol error: bad line length %d"),
 370                                      len);
 371                 die(_("protocol error: bad line length %d"), len);
 372         }
 373
 374         len -= 4;
 375         if ((unsigned)len >= size) {
 376                 if (options & PACKET_READ_GENTLE_ON_READ_ERROR)
 377                         return error(_("protocol error: bad line length %d"),
 378                                      len);
 379                 die(_("protocol error: bad line length %d"), len);
 380         }
 381
 382         if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
 383                 *pktlen = -1;
 384                 return PACKET_READ_EOF;
 385         }
 386
 387         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 388             len && buffer[len-1] == '\n')
 389                 len--;
 390
 391         buffer[len] = 0;
 392         packet_trace(buffer, len, 0);
 393
 394         if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
 395             starts_with(buffer, "ERR "))
 396                 die(_("remote error: %s"), buffer + 4);
 397
 398         *pktlen = len;
 399         return PACKET_READ_NORMAL;
 400 }
 401
 402 int packet_read(int fd, char **src_buffer, size_t *src_len,
 403                 char *buffer, unsigned size, int options)
 404 {
 405         int pktlen = -1;
 406
 407         packet_read_with_status(fd, src_buffer, src_len, buffer, size,
 408                                 &pktlen, options);
 409
 410         return pktlen;
 411 }
 412
 413 static char *packet_read_line_generic(int fd,
 414                                       char **src, size_t *src_len,
 415                                       int *dst_len)
 416 {
 417         int len = packet_read(fd, src, src_len,
 418                               packet_buffer, sizeof(packet_buffer),
 419                               PACKET_READ_CHOMP_NEWLINE);
 420         if (dst_len)
 421                 *dst_len = len;
 422         return (len > 0) ? packet_buffer : NULL;
 423 }
 424
 425 char *packet_read_line(int fd, int *len_p)
 426 {
 427         return packet_read_line_generic(fd, NULL, NULL, len_p);
 428 }
 429
 430 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
 431 {
 432         int len = packet_read(fd, NULL, NULL,
 433                               packet_buffer, sizeof(packet_buffer),
 434                               PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
 435         if (dst_len)
 436                 *dst_len = len;
 437         if (dst_line)
 438                 *dst_line = (len > 0) ? packet_buffer : NULL;
 439         return len;
 440 }
 441
 442 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 443 {
 444         return packet_read_line_generic(-1, src, src_len, dst_len);
 445 }
 446
 447 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options)
 448 {
 449         int packet_len;
 450
 451         size_t orig_len = sb_out->len;
 452         size_t orig_alloc = sb_out->alloc;
 453
 454         for (;;) {
 455                 strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
 456                 packet_len = packet_read(fd_in, NULL, NULL,
 457                         /* strbuf_grow() above always allocates one extra byte to
 458                          * store a '\0' at the end of the string. packet_read()
 459                          * writes a '\0' extra byte at the end, too. Let it know
 460                          * that there is already room for the extra byte.
 461                          */
 462                         sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
 463                         options);
 464                 if (packet_len <= 0)
 465                         break;
 466                 sb_out->len += packet_len;
 467         }
 468
 469         if (packet_len < 0) {
 470                 if (orig_alloc == 0)
 471                         strbuf_release(sb_out);
 472                 else
 473                         strbuf_setlen(sb_out, orig_len);
 474                 return packet_len;
 475         }
 476         return sb_out->len - orig_len;
 477 }
 478
 479 int recv_sideband(const char *me, int in_stream, int out)
 480 {
 481         char buf[LARGE_PACKET_MAX + 1];
 482         int len;
 483         struct strbuf scratch = STRBUF_INIT;
 484         enum sideband_type sideband_type;
 485
 486         while (1) {
 487                 int status = packet_read_with_status(in_stream, NULL, NULL,
 488                                                      buf, LARGE_PACKET_MAX,
 489                                                      &len,
 490                                                      PACKET_READ_GENTLE_ON_EOF);
 491                 if (!demultiplex_sideband(me, status, buf, len, 0, &scratch,
 492                                           &sideband_type))
 493                         continue;
 494                 switch (sideband_type) {
 495                 case SIDEBAND_PRIMARY:
 496                         write_or_die(out, buf + 1, len - 1);
 497                         break;
 498                 default: /* errors: message already written */
 499                         if (scratch.len > 0)
 500                                 BUG("unhandled incomplete sideband: '%s'",
 501                                     scratch.buf);
 502                         return sideband_type;
 503                 }
 504         }
 505 }
 506
 507 /* Packet Reader Functions */
 508 void packet_reader_init(struct packet_reader *reader, int fd,
 509                         char *src_buffer, size_t src_len,
 510                         int options)
 511 {
 512         memset(reader, 0, sizeof(*reader));
 513
 514         reader->fd = fd;
 515         reader->src_buffer = src_buffer;
 516         reader->src_len = src_len;
 517         reader->buffer = packet_buffer;
 518         reader->buffer_size = sizeof(packet_buffer);
 519         reader->options = options;
 520         reader->me = "git";
 521         reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 522 }
 523
 524 enum packet_read_status packet_reader_read(struct packet_reader *reader)
 525 {
 526         struct strbuf scratch = STRBUF_INIT;
 527
 528         if (reader->line_peeked) {
 529                 reader->line_peeked = 0;
 530                 return reader->status;
 531         }
 532
 533         /*
 534          * Consume all progress packets until a primary payload packet is
 535          * received
 536          */
 537         while (1) {
 538                 enum sideband_type sideband_type;
 539                 reader->status = packet_read_with_status(reader->fd,
 540                                                          &reader->src_buffer,
 541                                                          &reader->src_len,
 542                                                          reader->buffer,
 543                                                          reader->buffer_size,
 544                                                          &reader->pktlen,
 545                                                          reader->options);
 546                 if (!reader->use_sideband)
 547                         break;
 548                 if (demultiplex_sideband(reader->me, reader->status,
 549                                          reader->buffer, reader->pktlen, 1,
 550                                          &scratch, &sideband_type))
 551                         break;
 552         }
 553
 554         if (reader->status == PACKET_READ_NORMAL)
 555                 /* Skip the sideband designator if sideband is used */
 556                 reader->line = reader->use_sideband ?
 557                         reader->buffer + 1 : reader->buffer;
 558         else
 559                 reader->line = NULL;
 560
 561         return reader->status;
 562 }
 563
 564 enum packet_read_status packet_reader_peek(struct packet_reader *reader)
 565 {
 566         /* Only allow peeking a single line */
 567         if (reader->line_peeked)
 568                 return reader->status;
 569
 570         /* Peek a line by reading it and setting peeked flag */
 571         packet_reader_read(reader);
 572         reader->line_peeked = 1;
 573         return reader->status;
 574 }
 575
 576 void packet_writer_init(struct packet_writer *writer, int dest_fd)
 577 {
 578         writer->dest_fd = dest_fd;
 579         writer->use_sideband = 0;
 580 }
 581
 582 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
 583 {
 584         va_list args;
 585
 586         va_start(args, fmt);
 587         packet_write_fmt_1(writer->dest_fd, 0,
 588                            writer->use_sideband ? "\001" : "", fmt, args);
 589         va_end(args);
 590 }
 591
 592 void packet_writer_error(struct packet_writer *writer, const char *fmt, ...)
 593 {
 594         va_list args;
 595
 596         va_start(args, fmt);
 597         packet_write_fmt_1(writer->dest_fd, 0,
 598                            writer->use_sideband ? "\003" : "ERR ", fmt, args);
 599         va_end(args);
 600 }
 601
 602 void packet_writer_delim(struct packet_writer *writer)
 603 {
 604         packet_delim(writer->dest_fd);
 605 }
 606
 607 void packet_writer_flush(struct packet_writer *writer)
 608 {
 609         packet_flush(writer->dest_fd);
 610 }