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         write_or_die(fd, "0000", 4);
  92 }
  93
  94 void packet_delim(int fd)
  95 {
  96         packet_trace("0001", 4, 1);
  97         write_or_die(fd, "0001", 4);
  98 }
  99
 100 int packet_flush_gently(int fd)
 101 {
 102         packet_trace("0000", 4, 1);
 103         if (write_in_full(fd, "0000", 4) < 0)
 104                 return error("flush packet write failed");
 105         return 0;
 106 }
 107
 108 void packet_buf_flush(struct strbuf *buf)
 109 {
 110         packet_trace("0000", 4, 1);
 111         strbuf_add(buf, "0000", 4);
 112 }
 113
 114 void packet_buf_delim(struct strbuf *buf)
 115 {
 116         packet_trace("0001", 4, 1);
 117         strbuf_add(buf, "0001", 4);
 118 }
 119
 120 static void set_packet_header(char *buf, const int size)
 121 {
 122         static char hexchar[] = "0123456789abcdef";
 123
 124         #define hex(a) (hexchar[(a) & 15])
 125         buf[0] = hex(size >> 12);
 126         buf[1] = hex(size >> 8);
 127         buf[2] = hex(size >> 4);
 128         buf[3] = hex(size);
 129         #undef hex
 130 }
 131
 132 static void format_packet(struct strbuf *out, const char *fmt, va_list args)
 133 {
 134         size_t orig_len, n;
 135
 136         orig_len = out->len;
 137         strbuf_addstr(out, "0000");
 138         strbuf_vaddf(out, fmt, args);
 139         n = out->len - orig_len;
 140
 141         if (n > LARGE_PACKET_MAX)
 142                 die("protocol error: impossibly long line");
 143
 144         set_packet_header(&out->buf[orig_len], n);
 145         packet_trace(out->buf + orig_len + 4, n - 4, 1);
 146 }
 147
 148 static int packet_write_fmt_1(int fd, int gently,
 149                               const char *fmt, va_list args)
 150 {
 151         static struct strbuf buf = STRBUF_INIT;
 152
 153         strbuf_reset(&buf);
 154         format_packet(&buf, fmt, args);
 155         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 156                 if (!gently) {
 157                         check_pipe(errno);
 158                         die_errno("packet write with format failed");
 159                 }
 160                 return error("packet write with format failed");
 161         }
 162
 163         return 0;
 164 }
 165
 166 void packet_write_fmt(int fd, const char *fmt, ...)
 167 {
 168         va_list args;
 169
 170         va_start(args, fmt);
 171         packet_write_fmt_1(fd, 0, fmt, args);
 172         va_end(args);
 173 }
 174
 175 int packet_write_fmt_gently(int fd, const char *fmt, ...)
 176 {
 177         int status;
 178         va_list args;
 179
 180         va_start(args, fmt);
 181         status = packet_write_fmt_1(fd, 1, fmt, args);
 182         va_end(args);
 183         return status;
 184 }
 185
 186 static int packet_write_gently(const int fd_out, const char *buf, size_t size)
 187 {
 188         static char packet_write_buffer[LARGE_PACKET_MAX];
 189         size_t packet_size;
 190
 191         if (size > sizeof(packet_write_buffer) - 4)
 192                 return error("packet write failed - data exceeds max packet size");
 193
 194         packet_trace(buf, size, 1);
 195         packet_size = size + 4;
 196         set_packet_header(packet_write_buffer, packet_size);
 197         memcpy(packet_write_buffer + 4, buf, size);
 198         if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0)
 199                 return error("packet write failed");
 200         return 0;
 201 }
 202
 203 void packet_write(int fd_out, const char *buf, size_t size)
 204 {
 205         if (packet_write_gently(fd_out, buf, size))
 206                 die_errno("packet write failed");
 207 }
 208
 209 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 210 {
 211         va_list args;
 212
 213         va_start(args, fmt);
 214         format_packet(buf, fmt, args);
 215         va_end(args);
 216 }
 217
 218 void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
 219 {
 220         size_t orig_len, n;
 221
 222         orig_len = buf->len;
 223         strbuf_addstr(buf, "0000");
 224         strbuf_add(buf, data, len);
 225         n = buf->len - orig_len;
 226
 227         if (n > LARGE_PACKET_MAX)
 228                 die("protocol error: impossibly long line");
 229
 230         set_packet_header(&buf->buf[orig_len], n);
 231         packet_trace(data, len, 1);
 232 }
 233
 234 int write_packetized_from_fd(int fd_in, int fd_out)
 235 {
 236         static char buf[LARGE_PACKET_DATA_MAX];
 237         int err = 0;
 238         ssize_t bytes_to_write;
 239
 240         while (!err) {
 241                 bytes_to_write = xread(fd_in, buf, sizeof(buf));
 242                 if (bytes_to_write < 0)
 243                         return COPY_READ_ERROR;
 244                 if (bytes_to_write == 0)
 245                         break;
 246                 err = packet_write_gently(fd_out, buf, bytes_to_write);
 247         }
 248         if (!err)
 249                 err = packet_flush_gently(fd_out);
 250         return err;
 251 }
 252
 253 int write_packetized_from_buf(const char *src_in, size_t len, int fd_out)
 254 {
 255         int err = 0;
 256         size_t bytes_written = 0;
 257         size_t bytes_to_write;
 258
 259         while (!err) {
 260                 if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
 261                         bytes_to_write = LARGE_PACKET_DATA_MAX;
 262                 else
 263                         bytes_to_write = len - bytes_written;
 264                 if (bytes_to_write == 0)
 265                         break;
 266                 err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
 267                 bytes_written += bytes_to_write;
 268         }
 269         if (!err)
 270                 err = packet_flush_gently(fd_out);
 271         return err;
 272 }
 273
 274 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 275                            void *dst, unsigned size, int options)
 276 {
 277         ssize_t ret;
 278
 279         if (fd >= 0 && src_buf && *src_buf)
 280                 die("BUG: multiple sources given to packet_read");
 281
 282         /* Read up to "size" bytes from our source, whatever it is. */
 283         if (src_buf && *src_buf) {
 284                 ret = size < *src_size ? size : *src_size;
 285                 memcpy(dst, *src_buf, ret);
 286                 *src_buf += ret;
 287                 *src_size -= ret;
 288         } else {
 289                 ret = read_in_full(fd, dst, size);
 290                 if (ret < 0)
 291                         die_errno("read error");
 292         }
 293
 294         /* And complain if we didn't get enough bytes to satisfy the read. */
 295         if (ret != size) {
 296                 if (options & PACKET_READ_GENTLE_ON_EOF)
 297                         return -1;
 298
 299                 die("The remote end hung up unexpectedly");
 300         }
 301
 302         return ret;
 303 }
 304
 305 static int packet_length(const char *linelen)
 306 {
 307         int val = hex2chr(linelen);
 308         return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
 309 }
 310
 311 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 312                                                 size_t *src_len, char *buffer,
 313                                                 unsigned size, int *pktlen,
 314                                                 int options)
 315 {
 316         int len;
 317         char linelen[4];
 318
 319         if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
 320                 *pktlen = -1;
 321                 return PACKET_READ_EOF;
 322         }
 323
 324         len = packet_length(linelen);
 325
 326         if (len < 0) {
 327                 die("protocol error: bad line length character: %.4s", linelen);
 328         } else if (!len) {
 329                 packet_trace("0000", 4, 0);
 330                 *pktlen = 0;
 331                 return PACKET_READ_FLUSH;
 332         } else if (len == 1) {
 333                 packet_trace("0001", 4, 0);
 334                 *pktlen = 0;
 335                 return PACKET_READ_DELIM;
 336         } else if (len < 4) {
 337                 die("protocol error: bad line length %d", len);
 338         }
 339
 340         len -= 4;
 341         if ((unsigned)len >= size)
 342                 die("protocol error: bad line length %d", len);
 343
 344         if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
 345                 *pktlen = -1;
 346                 return PACKET_READ_EOF;
 347         }
 348
 349         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 350             len && buffer[len-1] == '\n')
 351                 len--;
 352
 353         buffer[len] = 0;
 354         packet_trace(buffer, len, 0);
 355         *pktlen = len;
 356         return PACKET_READ_NORMAL;
 357 }
 358
 359 int packet_read(int fd, char **src_buffer, size_t *src_len,
 360                 char *buffer, unsigned size, int options)
 361 {
 362         int pktlen = -1;
 363
 364         packet_read_with_status(fd, src_buffer, src_len, buffer, size,
 365                                 &pktlen, options);
 366
 367         return pktlen;
 368 }
 369
 370 static char *packet_read_line_generic(int fd,
 371                                       char **src, size_t *src_len,
 372                                       int *dst_len)
 373 {
 374         int len = packet_read(fd, src, src_len,
 375                               packet_buffer, sizeof(packet_buffer),
 376                               PACKET_READ_CHOMP_NEWLINE);
 377         if (dst_len)
 378                 *dst_len = len;
 379         return (len > 0) ? packet_buffer : NULL;
 380 }
 381
 382 char *packet_read_line(int fd, int *len_p)
 383 {
 384         return packet_read_line_generic(fd, NULL, NULL, len_p);
 385 }
 386
 387 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
 388 {
 389         int len = packet_read(fd, NULL, NULL,
 390                               packet_buffer, sizeof(packet_buffer),
 391                               PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
 392         if (dst_len)
 393                 *dst_len = len;
 394         if (dst_line)
 395                 *dst_line = (len > 0) ? packet_buffer : NULL;
 396         return len;
 397 }
 398
 399 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 400 {
 401         return packet_read_line_generic(-1, src, src_len, dst_len);
 402 }
 403
 404 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
 405 {
 406         int packet_len;
 407
 408         size_t orig_len = sb_out->len;
 409         size_t orig_alloc = sb_out->alloc;
 410
 411         for (;;) {
 412                 strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
 413                 packet_len = packet_read(fd_in, NULL, NULL,
 414                         /* strbuf_grow() above always allocates one extra byte to
 415                          * store a '\0' at the end of the string. packet_read()
 416                          * writes a '\0' extra byte at the end, too. Let it know
 417                          * that there is already room for the extra byte.
 418                          */
 419                         sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
 420                         PACKET_READ_GENTLE_ON_EOF);
 421                 if (packet_len <= 0)
 422                         break;
 423                 sb_out->len += packet_len;
 424         }
 425
 426         if (packet_len < 0) {
 427                 if (orig_alloc == 0)
 428                         strbuf_release(sb_out);
 429                 else
 430                         strbuf_setlen(sb_out, orig_len);
 431                 return packet_len;
 432         }
 433         return sb_out->len - orig_len;
 434 }
 435
 436 /* Packet Reader Functions */
 437 void packet_reader_init(struct packet_reader *reader, int fd,
 438                         char *src_buffer, size_t src_len,
 439                         int options)
 440 {
 441         memset(reader, 0, sizeof(*reader));
 442
 443         reader->fd = fd;
 444         reader->src_buffer = src_buffer;
 445         reader->src_len = src_len;
 446         reader->buffer = packet_buffer;
 447         reader->buffer_size = sizeof(packet_buffer);
 448         reader->options = options;
 449 }
 450
 451 enum packet_read_status packet_reader_read(struct packet_reader *reader)
 452 {
 453         if (reader->line_peeked) {
 454                 reader->line_peeked = 0;
 455                 return reader->status;
 456         }
 457
 458         reader->status = packet_read_with_status(reader->fd,
 459                                                  &reader->src_buffer,
 460                                                  &reader->src_len,
 461                                                  reader->buffer,
 462                                                  reader->buffer_size,
 463                                                  &reader->pktlen,
 464                                                  reader->options);
 465
 466         if (reader->status == PACKET_READ_NORMAL)
 467                 reader->line = reader->buffer;
 468         else
 469                 reader->line = NULL;
 470
 471         return reader->status;
 472 }
 473
 474 enum packet_read_status packet_reader_peek(struct packet_reader *reader)
 475 {
 476         /* Only allow peeking a single line */
 477         if (reader->line_peeked)
 478                 return reader->status;
 479
 480         /* Peek a line by reading it and setting peeked flag */
 481         packet_reader_read(reader);
 482         reader->line_peeked = 1;
 483         return reader->status;
 484 }