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 int packet_flush_gently(int fd)
 103 {
 104         packet_trace("0000", 4, 1);
 105         if (write_in_full(fd, "0000", 4) < 0)
 106                 return error(_("flush packet write failed"));
 107         return 0;
 108 }
 109
 110 void packet_buf_flush(struct strbuf *buf)
 111 {
 112         packet_trace("0000", 4, 1);
 113         strbuf_add(buf, "0000", 4);
 114 }
 115
 116 void packet_buf_delim(struct strbuf *buf)
 117 {
 118         packet_trace("0001", 4, 1);
 119         strbuf_add(buf, "0001", 4);
 120 }
 121
 122 void set_packet_header(char *buf, const int size)
 123 {
 124         static char hexchar[] = "0123456789abcdef";
 125
 126         #define hex(a) (hexchar[(a) & 15])
 127         buf[0] = hex(size >> 12);
 128         buf[1] = hex(size >> 8);
 129         buf[2] = hex(size >> 4);
 130         buf[3] = hex(size);
 131         #undef hex
 132 }
 133
 134 static void format_packet(struct strbuf *out, const char *prefix,
 135                           const char *fmt, va_list args)
 136 {
 137         size_t orig_len, n;
 138
 139         orig_len = out->len;
 140         strbuf_addstr(out, "0000");
 141         strbuf_addstr(out, prefix);
 142         strbuf_vaddf(out, fmt, args);
 143         n = out->len - orig_len;
 144
 145         if (n > LARGE_PACKET_MAX)
 146                 die(_("protocol error: impossibly long line"));
 147
 148         set_packet_header(&out->buf[orig_len], n);
 149         packet_trace(out->buf + orig_len + 4, n - 4, 1);
 150 }
 151
 152 static int packet_write_fmt_1(int fd, int gently, const char *prefix,
 153                               const char *fmt, va_list args)
 154 {
 155         static struct strbuf buf = STRBUF_INIT;
 156
 157         strbuf_reset(&buf);
 158         format_packet(&buf, prefix, fmt, args);
 159         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 160                 if (!gently) {
 161                         check_pipe(errno);
 162                         die_errno(_("packet write with format failed"));
 163                 }
 164                 return error(_("packet write with format failed"));
 165         }
 166
 167         return 0;
 168 }
 169
 170 void packet_write_fmt(int fd, const char *fmt, ...)
 171 {
 172         va_list args;
 173
 174         va_start(args, fmt);
 175         packet_write_fmt_1(fd, 0, "", fmt, args);
 176         va_end(args);
 177 }
 178
 179 int packet_write_fmt_gently(int fd, const char *fmt, ...)
 180 {
 181         int status;
 182         va_list args;
 183
 184         va_start(args, fmt);
 185         status = packet_write_fmt_1(fd, 1, "", fmt, args);
 186         va_end(args);
 187         return status;
 188 }
 189
 190 static int packet_write_gently(const int fd_out, const char *buf, size_t size)
 191 {
 192         static char packet_write_buffer[LARGE_PACKET_MAX];
 193         size_t packet_size;
 194
 195         if (size > sizeof(packet_write_buffer) - 4)
 196                 return error(_("packet write failed - data exceeds max packet size"));
 197
 198         packet_trace(buf, size, 1);
 199         packet_size = size + 4;
 200         set_packet_header(packet_write_buffer, packet_size);
 201         memcpy(packet_write_buffer + 4, buf, size);
 202         if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0)
 203                 return error(_("packet write failed"));
 204         return 0;
 205 }
 206
 207 void packet_write(int fd_out, const char *buf, size_t size)
 208 {
 209         if (packet_write_gently(fd_out, buf, size))
 210                 die_errno(_("packet write failed"));
 211 }
 212
 213 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 214 {
 215         va_list args;
 216
 217         va_start(args, fmt);
 218         format_packet(buf, "", fmt, args);
 219         va_end(args);
 220 }
 221
 222 void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
 223 {
 224         size_t orig_len, n;
 225
 226         orig_len = buf->len;
 227         strbuf_addstr(buf, "0000");
 228         strbuf_add(buf, data, len);
 229         n = buf->len - orig_len;
 230
 231         if (n > LARGE_PACKET_MAX)
 232                 die(_("protocol error: impossibly long line"));
 233
 234         set_packet_header(&buf->buf[orig_len], n);
 235         packet_trace(data, len, 1);
 236 }
 237
 238 int write_packetized_from_fd(int fd_in, int fd_out)
 239 {
 240         static char buf[LARGE_PACKET_DATA_MAX];
 241         int err = 0;
 242         ssize_t bytes_to_write;
 243
 244         while (!err) {
 245                 bytes_to_write = xread(fd_in, buf, sizeof(buf));
 246                 if (bytes_to_write < 0)
 247                         return COPY_READ_ERROR;
 248                 if (bytes_to_write == 0)
 249                         break;
 250                 err = packet_write_gently(fd_out, buf, bytes_to_write);
 251         }
 252         if (!err)
 253                 err = packet_flush_gently(fd_out);
 254         return err;
 255 }
 256
 257 int write_packetized_from_buf(const char *src_in, size_t len, int fd_out)
 258 {
 259         int err = 0;
 260         size_t bytes_written = 0;
 261         size_t bytes_to_write;
 262
 263         while (!err) {
 264                 if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
 265                         bytes_to_write = LARGE_PACKET_DATA_MAX;
 266                 else
 267                         bytes_to_write = len - bytes_written;
 268                 if (bytes_to_write == 0)
 269                         break;
 270                 err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
 271                 bytes_written += bytes_to_write;
 272         }
 273         if (!err)
 274                 err = packet_flush_gently(fd_out);
 275         return err;
 276 }
 277
 278 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 279                            void *dst, unsigned size, int options)
 280 {
 281         ssize_t ret;
 282
 283         if (fd >= 0 && src_buf && *src_buf)
 284                 BUG("multiple sources given to packet_read");
 285
 286         /* Read up to "size" bytes from our source, whatever it is. */
 287         if (src_buf && *src_buf) {
 288                 ret = size < *src_size ? size : *src_size;
 289                 memcpy(dst, *src_buf, ret);
 290                 *src_buf += ret;
 291                 *src_size -= ret;
 292         } else {
 293                 ret = read_in_full(fd, dst, size);
 294                 if (ret < 0)
 295                         die_errno(_("read error"));
 296         }
 297
 298         /* And complain if we didn't get enough bytes to satisfy the read. */
 299         if (ret != size) {
 300                 if (options & PACKET_READ_GENTLE_ON_EOF)
 301                         return -1;
 302
 303                 die(_("the remote end hung up unexpectedly"));
 304         }
 305
 306         return ret;
 307 }
 308
 309 static int packet_length(const char *linelen)
 310 {
 311         int val = hex2chr(linelen);
 312         return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
 313 }
 314
 315 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 316                                                 size_t *src_len, char *buffer,
 317                                                 unsigned size, int *pktlen,
 318                                                 int options)
 319 {
 320         int len;
 321         char linelen[4];
 322
 323         if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
 324                 *pktlen = -1;
 325                 return PACKET_READ_EOF;
 326         }
 327
 328         len = packet_length(linelen);
 329
 330         if (len < 0) {
 331                 die(_("protocol error: bad line length character: %.4s"), linelen);
 332         } else if (!len) {
 333                 packet_trace("0000", 4, 0);
 334                 *pktlen = 0;
 335                 return PACKET_READ_FLUSH;
 336         } else if (len == 1) {
 337                 packet_trace("0001", 4, 0);
 338                 *pktlen = 0;
 339                 return PACKET_READ_DELIM;
 340         } else if (len < 4) {
 341                 die(_("protocol error: bad line length %d"), len);
 342         }
 343
 344         len -= 4;
 345         if ((unsigned)len >= size)
 346                 die(_("protocol error: bad line length %d"), len);
 347
 348         if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
 349                 *pktlen = -1;
 350                 return PACKET_READ_EOF;
 351         }
 352
 353         if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
 354             starts_with(buffer, "ERR "))
 355                 die(_("remote error: %s"), buffer + 4);
 356
 357         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 358             len && buffer[len-1] == '\n')
 359                 len--;
 360
 361         buffer[len] = 0;
 362         packet_trace(buffer, len, 0);
 363         *pktlen = len;
 364         return PACKET_READ_NORMAL;
 365 }
 366
 367 int packet_read(int fd, char **src_buffer, size_t *src_len,
 368                 char *buffer, unsigned size, int options)
 369 {
 370         int pktlen = -1;
 371
 372         packet_read_with_status(fd, src_buffer, src_len, buffer, size,
 373                                 &pktlen, options);
 374
 375         return pktlen;
 376 }
 377
 378 static char *packet_read_line_generic(int fd,
 379                                       char **src, size_t *src_len,
 380                                       int *dst_len)
 381 {
 382         int len = packet_read(fd, src, src_len,
 383                               packet_buffer, sizeof(packet_buffer),
 384                               PACKET_READ_CHOMP_NEWLINE);
 385         if (dst_len)
 386                 *dst_len = len;
 387         return (len > 0) ? packet_buffer : NULL;
 388 }
 389
 390 char *packet_read_line(int fd, int *len_p)
 391 {
 392         return packet_read_line_generic(fd, NULL, NULL, len_p);
 393 }
 394
 395 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
 396 {
 397         int len = packet_read(fd, NULL, NULL,
 398                               packet_buffer, sizeof(packet_buffer),
 399                               PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
 400         if (dst_len)
 401                 *dst_len = len;
 402         if (dst_line)
 403                 *dst_line = (len > 0) ? packet_buffer : NULL;
 404         return len;
 405 }
 406
 407 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 408 {
 409         return packet_read_line_generic(-1, src, src_len, dst_len);
 410 }
 411
 412 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
 413 {
 414         int packet_len;
 415
 416         size_t orig_len = sb_out->len;
 417         size_t orig_alloc = sb_out->alloc;
 418
 419         for (;;) {
 420                 strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
 421                 packet_len = packet_read(fd_in, NULL, NULL,
 422                         /* strbuf_grow() above always allocates one extra byte to
 423                          * store a '\0' at the end of the string. packet_read()
 424                          * writes a '\0' extra byte at the end, too. Let it know
 425                          * that there is already room for the extra byte.
 426                          */
 427                         sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
 428                         PACKET_READ_GENTLE_ON_EOF);
 429                 if (packet_len <= 0)
 430                         break;
 431                 sb_out->len += packet_len;
 432         }
 433
 434         if (packet_len < 0) {
 435                 if (orig_alloc == 0)
 436                         strbuf_release(sb_out);
 437                 else
 438                         strbuf_setlen(sb_out, orig_len);
 439                 return packet_len;
 440         }
 441         return sb_out->len - orig_len;
 442 }
 443
 444 int recv_sideband(const char *me, int in_stream, int out)
 445 {
 446         char buf[LARGE_PACKET_MAX + 1];
 447         int len;
 448         struct strbuf scratch = STRBUF_INIT;
 449         enum sideband_type sideband_type;
 450
 451         while (1) {
 452                 len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX,
 453                                   0);
 454                 if (!demultiplex_sideband(me, buf, len, 0, &scratch,
 455                                           &sideband_type))
 456                         continue;
 457                 switch (sideband_type) {
 458                 case SIDEBAND_PRIMARY:
 459                         write_or_die(out, buf + 1, len - 1);
 460                         break;
 461                 default: /* errors: message already written */
 462                         return sideband_type;
 463                 }
 464         }
 465 }
 466
 467 /* Packet Reader Functions */
 468 void packet_reader_init(struct packet_reader *reader, int fd,
 469                         char *src_buffer, size_t src_len,
 470                         int options)
 471 {
 472         memset(reader, 0, sizeof(*reader));
 473
 474         reader->fd = fd;
 475         reader->src_buffer = src_buffer;
 476         reader->src_len = src_len;
 477         reader->buffer = packet_buffer;
 478         reader->buffer_size = sizeof(packet_buffer);
 479         reader->options = options;
 480         reader->me = "git";
 481 }
 482
 483 enum packet_read_status packet_reader_read(struct packet_reader *reader)
 484 {
 485         struct strbuf scratch = STRBUF_INIT;
 486
 487         if (reader->line_peeked) {
 488                 reader->line_peeked = 0;
 489                 return reader->status;
 490         }
 491
 492         /*
 493          * Consume all progress packets until a primary payload packet is
 494          * received
 495          */
 496         while (1) {
 497                 enum sideband_type sideband_type;
 498                 reader->status = packet_read_with_status(reader->fd,
 499                                                          &reader->src_buffer,
 500                                                          &reader->src_len,
 501                                                          reader->buffer,
 502                                                          reader->buffer_size,
 503                                                          &reader->pktlen,
 504                                                          reader->options);
 505                 if (!reader->use_sideband)
 506                         break;
 507                 if (demultiplex_sideband(reader->me, reader->buffer,
 508                                          reader->pktlen, 1, &scratch,
 509                                          &sideband_type))
 510                         break;
 511         }
 512
 513         if (reader->status == PACKET_READ_NORMAL)
 514                 /* Skip the sideband designator if sideband is used */
 515                 reader->line = reader->use_sideband ?
 516                         reader->buffer + 1 : reader->buffer;
 517         else
 518                 reader->line = NULL;
 519
 520         return reader->status;
 521 }
 522
 523 enum packet_read_status packet_reader_peek(struct packet_reader *reader)
 524 {
 525         /* Only allow peeking a single line */
 526         if (reader->line_peeked)
 527                 return reader->status;
 528
 529         /* Peek a line by reading it and setting peeked flag */
 530         packet_reader_read(reader);
 531         reader->line_peeked = 1;
 532         return reader->status;
 533 }
 534
 535 void packet_writer_init(struct packet_writer *writer, int dest_fd)
 536 {
 537         writer->dest_fd = dest_fd;
 538         writer->use_sideband = 0;
 539 }
 540
 541 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...)
 542 {
 543         va_list args;
 544
 545         va_start(args, fmt);
 546         packet_write_fmt_1(writer->dest_fd, 0,
 547                            writer->use_sideband ? "\001" : "", fmt, args);
 548         va_end(args);
 549 }
 550
 551 void packet_writer_error(struct packet_writer *writer, const char *fmt, ...)
 552 {
 553         va_list args;
 554
 555         va_start(args, fmt);
 556         packet_write_fmt_1(writer->dest_fd, 0,
 557                            writer->use_sideband ? "\003" : "ERR ", fmt, args);
 558         va_end(args);
 559 }
 560
 561 void packet_writer_delim(struct packet_writer *writer)
 562 {
 563         packet_delim(writer->dest_fd);
 564 }
 565
 566 void packet_writer_flush(struct packet_writer *writer)
 567 {
 568         packet_flush(writer->dest_fd);
 569 }