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 int packet_flush_gently(int fd)
  95 {
  96         packet_trace("0000", 4, 1);
  97         if (write_in_full(fd, "0000", 4) < 0)
  98                 return error("flush packet write failed");
  99         return 0;
 100 }
 101
 102 void packet_buf_flush(struct strbuf *buf)
 103 {
 104         packet_trace("0000", 4, 1);
 105         strbuf_add(buf, "0000", 4);
 106 }
 107
 108 static void set_packet_header(char *buf, const int size)
 109 {
 110         static char hexchar[] = "0123456789abcdef";
 111
 112         #define hex(a) (hexchar[(a) & 15])
 113         buf[0] = hex(size >> 12);
 114         buf[1] = hex(size >> 8);
 115         buf[2] = hex(size >> 4);
 116         buf[3] = hex(size);
 117         #undef hex
 118 }
 119
 120 static void format_packet(struct strbuf *out, const char *fmt, va_list args)
 121 {
 122         size_t orig_len, n;
 123
 124         orig_len = out->len;
 125         strbuf_addstr(out, "0000");
 126         strbuf_vaddf(out, fmt, args);
 127         n = out->len - orig_len;
 128
 129         if (n > LARGE_PACKET_MAX)
 130                 die("protocol error: impossibly long line");
 131
 132         set_packet_header(&out->buf[orig_len], n);
 133         packet_trace(out->buf + orig_len + 4, n - 4, 1);
 134 }
 135
 136 static int packet_write_fmt_1(int fd, int gently,
 137                               const char *fmt, va_list args)
 138 {
 139         static struct strbuf buf = STRBUF_INIT;
 140
 141         strbuf_reset(&buf);
 142         format_packet(&buf, fmt, args);
 143         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 144                 if (!gently) {
 145                         check_pipe(errno);
 146                         die_errno("packet write with format failed");
 147                 }
 148                 return error("packet write with format failed");
 149         }
 150
 151         return 0;
 152 }
 153
 154 void packet_write_fmt(int fd, const char *fmt, ...)
 155 {
 156         va_list args;
 157
 158         va_start(args, fmt);
 159         packet_write_fmt_1(fd, 0, fmt, args);
 160         va_end(args);
 161 }
 162
 163 int packet_write_fmt_gently(int fd, const char *fmt, ...)
 164 {
 165         int status;
 166         va_list args;
 167
 168         va_start(args, fmt);
 169         status = packet_write_fmt_1(fd, 1, fmt, args);
 170         va_end(args);
 171         return status;
 172 }
 173
 174 static int packet_write_gently(const int fd_out, const char *buf, size_t size)
 175 {
 176         static char packet_write_buffer[LARGE_PACKET_MAX];
 177         size_t packet_size;
 178
 179         if (size > sizeof(packet_write_buffer) - 4)
 180                 return error("packet write failed - data exceeds max packet size");
 181
 182         packet_trace(buf, size, 1);
 183         packet_size = size + 4;
 184         set_packet_header(packet_write_buffer, packet_size);
 185         memcpy(packet_write_buffer + 4, buf, size);
 186         if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0)
 187                 return error("packet write failed");
 188         return 0;
 189 }
 190
 191 void packet_write(int fd_out, const char *buf, size_t size)
 192 {
 193         if (packet_write_gently(fd_out, buf, size))
 194                 die_errno("packet write failed");
 195 }
 196
 197 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 198 {
 199         va_list args;
 200
 201         va_start(args, fmt);
 202         format_packet(buf, fmt, args);
 203         va_end(args);
 204 }
 205
 206 int write_packetized_from_fd(int fd_in, int fd_out)
 207 {
 208         static char buf[LARGE_PACKET_DATA_MAX];
 209         int err = 0;
 210         ssize_t bytes_to_write;
 211
 212         while (!err) {
 213                 bytes_to_write = xread(fd_in, buf, sizeof(buf));
 214                 if (bytes_to_write < 0)
 215                         return COPY_READ_ERROR;
 216                 if (bytes_to_write == 0)
 217                         break;
 218                 err = packet_write_gently(fd_out, buf, bytes_to_write);
 219         }
 220         if (!err)
 221                 err = packet_flush_gently(fd_out);
 222         return err;
 223 }
 224
 225 int write_packetized_from_buf(const char *src_in, size_t len, int fd_out)
 226 {
 227         int err = 0;
 228         size_t bytes_written = 0;
 229         size_t bytes_to_write;
 230
 231         while (!err) {
 232                 if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
 233                         bytes_to_write = LARGE_PACKET_DATA_MAX;
 234                 else
 235                         bytes_to_write = len - bytes_written;
 236                 if (bytes_to_write == 0)
 237                         break;
 238                 err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
 239                 bytes_written += bytes_to_write;
 240         }
 241         if (!err)
 242                 err = packet_flush_gently(fd_out);
 243         return err;
 244 }
 245
 246 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 247                            void *dst, unsigned size, int options)
 248 {
 249         ssize_t ret;
 250
 251         if (fd >= 0 && src_buf && *src_buf)
 252                 die("BUG: multiple sources given to packet_read");
 253
 254         /* Read up to "size" bytes from our source, whatever it is. */
 255         if (src_buf && *src_buf) {
 256                 ret = size < *src_size ? size : *src_size;
 257                 memcpy(dst, *src_buf, ret);
 258                 *src_buf += ret;
 259                 *src_size -= ret;
 260         } else {
 261                 ret = read_in_full(fd, dst, size);
 262                 if (ret < 0)
 263                         die_errno("read error");
 264         }
 265
 266         /* And complain if we didn't get enough bytes to satisfy the read. */
 267         if (ret != size) {
 268                 if (options & PACKET_READ_GENTLE_ON_EOF)
 269                         return -1;
 270
 271                 die("The remote end hung up unexpectedly");
 272         }
 273
 274         return ret;
 275 }
 276
 277 static int packet_length(const char *linelen)
 278 {
 279         int val = hex2chr(linelen);
 280         return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
 281 }
 282
 283 int packet_read(int fd, char **src_buf, size_t *src_len,
 284                 char *buffer, unsigned size, int options)
 285 {
 286         int len, ret;
 287         char linelen[4];
 288
 289         ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
 290         if (ret < 0)
 291                 return ret;
 292         len = packet_length(linelen);
 293         if (len < 0)
 294                 die("protocol error: bad line length character: %.4s", linelen);
 295         if (!len) {
 296                 packet_trace("0000", 4, 0);
 297                 return 0;
 298         }
 299         len -= 4;
 300         if (len >= size)
 301                 die("protocol error: bad line length %d", len);
 302         ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
 303         if (ret < 0)
 304                 return ret;
 305
 306         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 307             len && buffer[len-1] == '\n')
 308                 len--;
 309
 310         buffer[len] = 0;
 311         packet_trace(buffer, len, 0);
 312         return len;
 313 }
 314
 315 static char *packet_read_line_generic(int fd,
 316                                       char **src, size_t *src_len,
 317                                       int *dst_len)
 318 {
 319         int len = packet_read(fd, src, src_len,
 320                               packet_buffer, sizeof(packet_buffer),
 321                               PACKET_READ_CHOMP_NEWLINE);
 322         if (dst_len)
 323                 *dst_len = len;
 324         return (len > 0) ? packet_buffer : NULL;
 325 }
 326
 327 char *packet_read_line(int fd, int *len_p)
 328 {
 329         return packet_read_line_generic(fd, NULL, NULL, len_p);
 330 }
 331
 332 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
 333 {
 334         int len = packet_read(fd, NULL, NULL,
 335                               packet_buffer, sizeof(packet_buffer),
 336                               PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
 337         if (dst_len)
 338                 *dst_len = len;
 339         if (dst_line)
 340                 *dst_line = (len > 0) ? packet_buffer : NULL;
 341         return len;
 342 }
 343
 344 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 345 {
 346         return packet_read_line_generic(-1, src, src_len, dst_len);
 347 }
 348
 349 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
 350 {
 351         int packet_len;
 352
 353         size_t orig_len = sb_out->len;
 354         size_t orig_alloc = sb_out->alloc;
 355
 356         for (;;) {
 357                 strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
 358                 packet_len = packet_read(fd_in, NULL, NULL,
 359                         /* strbuf_grow() above always allocates one extra byte to
 360                          * store a '\0' at the end of the string. packet_read()
 361                          * writes a '\0' extra byte at the end, too. Let it know
 362                          * that there is already room for the extra byte.
 363                          */
 364                         sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
 365                         PACKET_READ_GENTLE_ON_EOF);
 366                 if (packet_len <= 0)
 367                         break;
 368                 sb_out->len += packet_len;
 369         }
 370
 371         if (packet_len < 0) {
 372                 if (orig_alloc == 0)
 373                         strbuf_release(sb_out);
 374                 else
 375                         strbuf_setlen(sb_out, orig_len);
 376                 return packet_len;
 377         }
 378         return sb_out->len - orig_len;
 379 }