upload-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "tag.h"
   5 #include "object.h"
   6 #include "commit.h"
   7 #include "exec_cmd.h"
   8 #include <signal.h>
   9 #include <sys/poll.h>
  10 #include <sys/wait.h>
  11
  12 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  13
  14 #define THEY_HAVE (1U << 0)
  15 #define OUR_REF (1U << 1)
  16 #define WANTED (1U << 2)
  17 #define MAX_HAS 256
  18 #define MAX_NEEDS 256
  19 static int nr_has = 0, nr_needs = 0, multi_ack = 0, nr_our_refs = 0;
  20 static int use_thin_pack = 0;
  21 static unsigned char has_sha1[MAX_HAS][20];
  22 static unsigned char needs_sha1[MAX_NEEDS][20];
  23 static unsigned int timeout = 0;
  24 static int use_sideband = 0;
  25
  26 static void reset_timeout(void)
  27 {
  28         alarm(timeout);
  29 }
  30
  31 static int strip(char *line, int len)
  32 {
  33         if (len && line[len-1] == '\n')
  34                 line[--len] = 0;
  35         return len;
  36 }
  37
  38 #define PACKET_MAX 1000
  39 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
  40 {
  41         ssize_t ssz;
  42         const char *p;
  43
  44         if (!data) {
  45                 if (!use_sideband)
  46                         return 0;
  47                 packet_flush(1);
  48         }
  49
  50         if (!use_sideband) {
  51                 if (fd == 3)
  52                         /* emergency quit */
  53                         fd = 2;
  54                 return safe_write(fd, data, sz);
  55         }
  56         p = data;
  57         ssz = sz;
  58         while (sz) {
  59                 unsigned n;
  60                 char hdr[5];
  61
  62                 n = sz;
  63                 if (PACKET_MAX - 5 < n)
  64                         n = PACKET_MAX - 5;
  65                 sprintf(hdr, "%04x", n + 5);
  66                 hdr[4] = fd;
  67                 safe_write(1, hdr, 5);
  68                 safe_write(1, p, n);
  69                 p += n;
  70                 sz -= n;
  71         }
  72         return ssz;
  73 }
  74
  75 static void create_pack_file(void)
  76 {
  77         /* Pipes between rev-list to pack-objects, pack-objects to us
  78          * and pack-objects error stream for progress bar.
  79          */
  80         int lp_pipe[2], pu_pipe[2], pe_pipe[2];
  81         pid_t pid_rev_list, pid_pack_objects;
  82         int create_full_pack = (nr_our_refs == nr_needs && !nr_has);
  83         char data[8193], progress[128];
  84         char abort_msg[] = "aborting due to possible repository "
  85                 "corruption on the remote side.";
  86         int buffered = -1;
  87
  88         if (pipe(lp_pipe) < 0)
  89                 die("git-upload-pack: unable to create pipe");
  90         pid_rev_list = fork();
  91         if (pid_rev_list < 0)
  92                 die("git-upload-pack: unable to fork git-rev-list");
  93
  94         if (!pid_rev_list) {
  95                 int i;
  96                 int args;
  97                 const char **argv;
  98                 char *buf;
  99                 char **p;
 100
 101                 if (create_full_pack) {
 102                         args = 10;
 103                         use_thin_pack = 0; /* no point doing it */
 104                 }
 105                 else
 106                         args = nr_has + nr_needs + 5;
 107                 p = xmalloc(args * sizeof(char *));
 108                 argv = (const char **) p;
 109                 buf = xmalloc(args * 45);
 110
 111                 dup2(lp_pipe[1], 1);
 112                 close(0);
 113                 close(lp_pipe[0]);
 114                 close(lp_pipe[1]);
 115                 *p++ = "rev-list";
 116                 *p++ = use_thin_pack ? "--objects-edge" : "--objects";
 117                 if (create_full_pack || MAX_NEEDS <= nr_needs)
 118                         *p++ = "--all";
 119                 else {
 120                         for (i = 0; i < nr_needs; i++) {
 121                                 *p++ = buf;
 122                                 memcpy(buf, sha1_to_hex(needs_sha1[i]), 41);
 123                                 buf += 41;
 124                         }
 125                 }
 126                 if (!create_full_pack)
 127                         for (i = 0; i < nr_has; i++) {
 128                                 *p++ = buf;
 129                                 *buf++ = '^';
 130                                 memcpy(buf, sha1_to_hex(has_sha1[i]), 41);
 131                                 buf += 41;
 132                         }
 133                 *p++ = NULL;
 134                 execv_git_cmd(argv);
 135                 die("git-upload-pack: unable to exec git-rev-list");
 136         }
 137
 138         if (pipe(pu_pipe) < 0)
 139                 die("git-upload-pack: unable to create pipe");
 140         if (pipe(pe_pipe) < 0)
 141                 die("git-upload-pack: unable to create pipe");
 142         pid_pack_objects = fork();
 143         if (pid_pack_objects < 0) {
 144                 /* daemon sets things up to ignore TERM */
 145                 kill(pid_rev_list, SIGKILL);
 146                 die("git-upload-pack: unable to fork git-pack-objects");
 147         }
 148         if (!pid_pack_objects) {
 149                 dup2(lp_pipe[0], 0);
 150                 dup2(pu_pipe[1], 1);
 151                 dup2(pe_pipe[1], 2);
 152
 153                 close(lp_pipe[0]);
 154                 close(lp_pipe[1]);
 155                 close(pu_pipe[0]);
 156                 close(pu_pipe[1]);
 157                 close(pe_pipe[0]);
 158                 close(pe_pipe[1]);
 159                 execl_git_cmd("pack-objects", "--stdout", "--progress", NULL);
 160                 kill(pid_rev_list, SIGKILL);
 161                 die("git-upload-pack: unable to exec git-pack-objects");
 162         }
 163
 164         close(lp_pipe[0]);
 165         close(lp_pipe[1]);
 166
 167         /* We read from pe_pipe[0] to capture stderr output for
 168          * progress bar, and pu_pipe[0] to capture the pack data.
 169          */
 170         close(pe_pipe[1]);
 171         close(pu_pipe[1]);
 172
 173         while (1) {
 174                 const char *who;
 175                 struct pollfd pfd[2];
 176                 pid_t pid;
 177                 int status;
 178                 ssize_t sz;
 179                 int pe, pu, pollsize;
 180
 181                 pollsize = 0;
 182                 pe = pu = -1;
 183
 184                 if (0 <= pu_pipe[0]) {
 185                         pfd[pollsize].fd = pu_pipe[0];
 186                         pfd[pollsize].events = POLLIN;
 187                         pu = pollsize;
 188                         pollsize++;
 189                 }
 190                 if (0 <= pe_pipe[0]) {
 191                         pfd[pollsize].fd = pe_pipe[0];
 192                         pfd[pollsize].events = POLLIN;
 193                         pe = pollsize;
 194                         pollsize++;
 195                 }
 196
 197                 if (pollsize) {
 198                         if (poll(pfd, pollsize, -1) < 0) {
 199                                 if (errno != EINTR) {
 200                                         error("poll failed, resuming: %s",
 201                                               strerror(errno));
 202                                         sleep(1);
 203                                 }
 204                                 continue;
 205                         }
 206                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 207                                 /* Data ready; we keep the last byte
 208                                  * to ourselves in case we detect
 209                                  * broken rev-list, so that we can
 210                                  * leave the stream corrupted.  This
 211                                  * is unfortunate -- unpack-objects
 212                                  * would happily accept a valid pack
 213                                  * data with trailing garbage, so
 214                                  * appending garbage after we pass all
 215                                  * the pack data is not good enough to
 216                                  * signal breakage to downstream.
 217                                  */
 218                                 char *cp = data;
 219                                 ssize_t outsz = 0;
 220                                 if (0 <= buffered) {
 221                                         *cp++ = buffered;
 222                                         outsz++;
 223                                 }
 224                                 sz = read(pu_pipe[0], cp,
 225                                           sizeof(data) - outsz);
 226                                 if (0 < sz)
 227                                                 ;
 228                                 else if (sz == 0) {
 229                                         close(pu_pipe[0]);
 230                                         pu_pipe[0] = -1;
 231                                 }
 232                                 else
 233                                         goto fail;
 234                                 sz += outsz;
 235                                 if (1 < sz) {
 236                                         buffered = data[sz-1] & 0xFF;
 237                                         sz--;
 238                                 }
 239                                 else
 240                                         buffered = -1;
 241                                 sz = send_client_data(1, data, sz);
 242                                 if (sz < 0)
 243                                         goto fail;
 244                         }
 245                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 246                                 /* Status ready; we ship that in the side-band
 247                                  * or dump to the standard error.
 248                                  */
 249                                 sz = read(pe_pipe[0], progress,
 250                                           sizeof(progress));
 251                                 if (0 < sz)
 252                                         send_client_data(2, progress, sz);
 253                                 else if (sz == 0) {
 254                                         close(pe_pipe[0]);
 255                                         pe_pipe[0] = -1;
 256                                 }
 257                                 else
 258                                         goto fail;
 259                         }
 260                 }
 261
 262                 /* See if the children are still there */
 263                 if (pid_rev_list || pid_pack_objects) {
 264                         pid = waitpid(-1, &status, WNOHANG);
 265                         if (!pid)
 266                                 continue;
 267                         who = ((pid == pid_rev_list) ? "git-rev-list" :
 268                                (pid == pid_pack_objects) ? "git-pack-objects" :
 269                                NULL);
 270                         if (!who) {
 271                                 if (pid < 0) {
 272                                         error("git-upload-pack: %s",
 273                                               strerror(errno));
 274                                         goto fail;
 275                                 }
 276                                 error("git-upload-pack: we weren't "
 277                                       "waiting for %d", pid);
 278                                 continue;
 279                         }
 280                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
 281                                 error("git-upload-pack: %s died with error.",
 282                                       who);
 283                                 goto fail;
 284                         }
 285                         if (pid == pid_rev_list)
 286                                 pid_rev_list = 0;
 287                         if (pid == pid_pack_objects)
 288                                 pid_pack_objects = 0;
 289                         if (pid_rev_list || pid_pack_objects)
 290                                 continue;
 291                 }
 292
 293                 /* both died happily */
 294                 if (pollsize)
 295                         continue;
 296
 297                 /* flush the data */
 298                 if (0 <= buffered) {
 299                         data[0] = buffered;
 300                         sz = send_client_data(1, data, 1);
 301                         if (sz < 0)
 302                                 goto fail;
 303                         fprintf(stderr, "flushed.\n");
 304                 }
 305                 send_client_data(1, NULL, 0);
 306                 return;
 307         }
 308  fail:
 309         if (pid_pack_objects)
 310                 kill(pid_pack_objects, SIGKILL);
 311         if (pid_rev_list)
 312                 kill(pid_rev_list, SIGKILL);
 313         send_client_data(3, abort_msg, sizeof(abort_msg));
 314         die("git-upload-pack: %s", abort_msg);
 315 }
 316
 317 static int got_sha1(char *hex, unsigned char *sha1)
 318 {
 319         if (get_sha1_hex(hex, sha1))
 320                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 321         if (!has_sha1_file(sha1))
 322                 return 0;
 323         if (nr_has < MAX_HAS) {
 324                 struct object *o = lookup_object(sha1);
 325                 if (!(o && o->parsed))
 326                         o = parse_object(sha1);
 327                 if (!o)
 328                         die("oops (%s)", sha1_to_hex(sha1));
 329                 if (o->type == TYPE_COMMIT) {
 330                         struct commit_list *parents;
 331                         if (o->flags & THEY_HAVE)
 332                                 return 0;
 333                         o->flags |= THEY_HAVE;
 334                         for (parents = ((struct commit*)o)->parents;
 335                              parents;
 336                              parents = parents->next)
 337                                 parents->item->object.flags |= THEY_HAVE;
 338                 }
 339                 memcpy(has_sha1[nr_has++], sha1, 20);
 340         }
 341         return 1;
 342 }
 343
 344 static int get_common_commits(void)
 345 {
 346         static char line[1000];
 347         unsigned char sha1[20], last_sha1[20];
 348         int len;
 349
 350         track_object_refs = 0;
 351         save_commit_buffer = 0;
 352
 353         for(;;) {
 354                 len = packet_read_line(0, line, sizeof(line));
 355                 reset_timeout();
 356
 357                 if (!len) {
 358                         if (nr_has == 0 || multi_ack)
 359                                 packet_write(1, "NAK\n");
 360                         continue;
 361                 }
 362                 len = strip(line, len);
 363                 if (!strncmp(line, "have ", 5)) {
 364                         if (got_sha1(line+5, sha1) &&
 365                                         (multi_ack || nr_has == 1)) {
 366                                 if (nr_has >= MAX_HAS)
 367                                         multi_ack = 0;
 368                                 packet_write(1, "ACK %s%s\n",
 369                                         sha1_to_hex(sha1),
 370                                         multi_ack ?  " continue" : "");
 371                                 if (multi_ack)
 372                                         memcpy(last_sha1, sha1, 20);
 373                         }
 374                         continue;
 375                 }
 376                 if (!strcmp(line, "done")) {
 377                         if (nr_has > 0) {
 378                                 if (multi_ack)
 379                                         packet_write(1, "ACK %s\n",
 380                                                         sha1_to_hex(last_sha1));
 381                                 return 0;
 382                         }
 383                         packet_write(1, "NAK\n");
 384                         return -1;
 385                 }
 386                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 387         }
 388 }
 389
 390 static int receive_needs(void)
 391 {
 392         static char line[1000];
 393         int len, needs;
 394
 395         needs = 0;
 396         for (;;) {
 397                 struct object *o;
 398                 unsigned char dummy[20], *sha1_buf;
 399                 len = packet_read_line(0, line, sizeof(line));
 400                 reset_timeout();
 401                 if (!len)
 402                         return needs;
 403
 404                 sha1_buf = dummy;
 405                 if (needs == MAX_NEEDS) {
 406                         fprintf(stderr,
 407                                 "warning: supporting only a max of %d requests. "
 408                                 "sending everything instead.\n",
 409                                 MAX_NEEDS);
 410                 }
 411                 else if (needs < MAX_NEEDS)
 412                         sha1_buf = needs_sha1[needs];
 413
 414                 if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf))
 415                         die("git-upload-pack: protocol error, "
 416                             "expected to get sha, not '%s'", line);
 417                 if (strstr(line+45, "multi_ack"))
 418                         multi_ack = 1;
 419                 if (strstr(line+45, "thin-pack"))
 420                         use_thin_pack = 1;
 421                 if (strstr(line+45, "side-band"))
 422                         use_sideband = 1;
 423
 424                 /* We have sent all our refs already, and the other end
 425                  * should have chosen out of them; otherwise they are
 426                  * asking for nonsense.
 427                  *
 428                  * Hmph.  We may later want to allow "want" line that
 429                  * asks for something like "master~10" (symbolic)...
 430                  * would it make sense?  I don't know.
 431                  */
 432                 o = lookup_object(sha1_buf);
 433                 if (!o || !(o->flags & OUR_REF))
 434                         die("git-upload-pack: not our ref %s", line+5);
 435                 if (!(o->flags & WANTED)) {
 436                         o->flags |= WANTED;
 437                         needs++;
 438                 }
 439         }
 440 }
 441
 442 static int send_ref(const char *refname, const unsigned char *sha1)
 443 {
 444         static char *capabilities = "multi_ack thin-pack side-band";
 445         struct object *o = parse_object(sha1);
 446
 447         if (!o)
 448                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 449
 450         if (capabilities)
 451                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 452                         0, capabilities);
 453         else
 454                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 455         capabilities = NULL;
 456         if (!(o->flags & OUR_REF)) {
 457                 o->flags |= OUR_REF;
 458                 nr_our_refs++;
 459         }
 460         if (o->type == TYPE_TAG) {
 461                 o = deref_tag(o, refname, 0);
 462                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 463         }
 464         return 0;
 465 }
 466
 467 static int upload_pack(void)
 468 {
 469         reset_timeout();
 470         head_ref(send_ref);
 471         for_each_ref(send_ref);
 472         packet_flush(1);
 473         nr_needs = receive_needs();
 474         if (!nr_needs)
 475                 return 0;
 476         get_common_commits();
 477         create_pack_file();
 478         return 0;
 479 }
 480
 481 int main(int argc, char **argv)
 482 {
 483         char *dir;
 484         int i;
 485         int strict = 0;
 486
 487         for (i = 1; i < argc; i++) {
 488                 char *arg = argv[i];
 489
 490                 if (arg[0] != '-')
 491                         break;
 492                 if (!strcmp(arg, "--strict")) {
 493                         strict = 1;
 494                         continue;
 495                 }
 496                 if (!strncmp(arg, "--timeout=", 10)) {
 497                         timeout = atoi(arg+10);
 498                         continue;
 499                 }
 500                 if (!strcmp(arg, "--")) {
 501                         i++;
 502                         break;
 503                 }
 504         }
 505
 506         if (i != argc-1)
 507                 usage(upload_pack_usage);
 508         dir = argv[i];
 509
 510         if (!enter_repo(dir, strict))
 511                 die("'%s': unable to chdir or not a git archive", dir);
 512
 513         upload_pack();
 514         return 0;
 515 }