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