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