upload-pack.c

   1 #include <signal.h>
   2 #include <sys/wait.h>
   3 #include <sys/poll.h>
   4 #include "cache.h"
   5 #include "refs.h"
   6 #include "pkt-line.h"
   7 #include "tag.h"
   8 #include "object.h"
   9 #include "commit.h"
  10 #include "exec_cmd.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                 if (fd == 2) {
  55                         xwrite(fd, data, sz);
  56                         return sz;
  57                 }
  58                 return safe_write(fd, data, sz);
  59         }
  60         p = data;
  61         ssz = sz;
  62         while (sz) {
  63                 unsigned n;
  64                 char hdr[5];
  65
  66                 n = sz;
  67                 if (PACKET_MAX - 5 < n)
  68                         n = PACKET_MAX - 5;
  69                 sprintf(hdr, "%04x", n + 5);
  70                 hdr[4] = fd;
  71                 safe_write(1, hdr, 5);
  72                 safe_write(1, p, n);
  73                 p += n;
  74                 sz -= n;
  75         }
  76         return ssz;
  77 }
  78
  79 static void create_pack_file(void)
  80 {
  81         /* Pipes between rev-list to pack-objects, pack-objects to us
  82          * and pack-objects error stream for progress bar.
  83          */
  84         int lp_pipe[2], pu_pipe[2], pe_pipe[2];
  85         pid_t pid_rev_list, pid_pack_objects;
  86         int create_full_pack = (nr_our_refs == nr_needs && !nr_has);
  87         char data[8193], progress[128];
  88         char abort_msg[] = "aborting due to possible repository "
  89                 "corruption on the remote side.";
  90         int buffered = -1;
  91
  92         if (pipe(lp_pipe) < 0)
  93                 die("git-upload-pack: unable to create pipe");
  94         pid_rev_list = fork();
  95         if (pid_rev_list < 0)
  96                 die("git-upload-pack: unable to fork git-rev-list");
  97
  98         if (!pid_rev_list) {
  99                 int i;
 100                 int args;
 101                 const char **argv;
 102                 const char **p;
 103                 char *buf;
 104
 105                 if (create_full_pack) {
 106                         args = 10;
 107                         use_thin_pack = 0; /* no point doing it */
 108                 }
 109                 else
 110                         args = nr_has + nr_needs + 5;
 111                 p = xmalloc(args * sizeof(char *));
 112                 argv = (const char **) p;
 113                 buf = xmalloc(args * 45);
 114
 115                 dup2(lp_pipe[1], 1);
 116                 close(0);
 117                 close(lp_pipe[0]);
 118                 close(lp_pipe[1]);
 119                 *p++ = "rev-list";
 120                 *p++ = use_thin_pack ? "--objects-edge" : "--objects";
 121                 if (create_full_pack || MAX_NEEDS <= nr_needs)
 122                         *p++ = "--all";
 123                 else {
 124                         for (i = 0; i < nr_needs; i++) {
 125                                 *p++ = buf;
 126                                 memcpy(buf, sha1_to_hex(needs_sha1[i]), 41);
 127                                 buf += 41;
 128                         }
 129                 }
 130                 if (!create_full_pack)
 131                         for (i = 0; i < nr_has; i++) {
 132                                 *p++ = buf;
 133                                 *buf++ = '^';
 134                                 memcpy(buf, sha1_to_hex(has_sha1[i]), 41);
 135                                 buf += 41;
 136                         }
 137                 *p++ = NULL;
 138                 execv_git_cmd(argv);
 139                 die("git-upload-pack: unable to exec git-rev-list");
 140         }
 141
 142         if (pipe(pu_pipe) < 0)
 143                 die("git-upload-pack: unable to create pipe");
 144         if (pipe(pe_pipe) < 0)
 145                 die("git-upload-pack: unable to create pipe");
 146         pid_pack_objects = fork();
 147         if (pid_pack_objects < 0) {
 148                 /* daemon sets things up to ignore TERM */
 149                 kill(pid_rev_list, SIGKILL);
 150                 die("git-upload-pack: unable to fork git-pack-objects");
 151         }
 152         if (!pid_pack_objects) {
 153                 dup2(lp_pipe[0], 0);
 154                 dup2(pu_pipe[1], 1);
 155                 dup2(pe_pipe[1], 2);
 156
 157                 close(lp_pipe[0]);
 158                 close(lp_pipe[1]);
 159                 close(pu_pipe[0]);
 160                 close(pu_pipe[1]);
 161                 close(pe_pipe[0]);
 162                 close(pe_pipe[1]);
 163                 execl_git_cmd("pack-objects", "--stdout", "--progress", NULL);
 164                 kill(pid_rev_list, SIGKILL);
 165                 die("git-upload-pack: unable to exec git-pack-objects");
 166         }
 167
 168         close(lp_pipe[0]);
 169         close(lp_pipe[1]);
 170
 171         /* We read from pe_pipe[0] to capture stderr output for
 172          * progress bar, and pu_pipe[0] to capture the pack data.
 173          */
 174         close(pe_pipe[1]);
 175         close(pu_pipe[1]);
 176
 177         while (1) {
 178                 const char *who;
 179                 struct pollfd pfd[2];
 180                 pid_t pid;
 181                 int status;
 182                 ssize_t sz;
 183                 int pe, pu, pollsize;
 184
 185                 pollsize = 0;
 186                 pe = pu = -1;
 187
 188                 if (0 <= pu_pipe[0]) {
 189                         pfd[pollsize].fd = pu_pipe[0];
 190                         pfd[pollsize].events = POLLIN;
 191                         pu = pollsize;
 192                         pollsize++;
 193                 }
 194                 if (0 <= pe_pipe[0]) {
 195                         pfd[pollsize].fd = pe_pipe[0];
 196                         pfd[pollsize].events = POLLIN;
 197                         pe = pollsize;
 198                         pollsize++;
 199                 }
 200
 201                 if (pollsize) {
 202                         if (poll(pfd, pollsize, -1) < 0) {
 203                                 if (errno != EINTR) {
 204                                         error("poll failed, resuming: %s",
 205                                               strerror(errno));
 206                                         sleep(1);
 207                                 }
 208                                 continue;
 209                         }
 210                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 211                                 /* Data ready; we keep the last byte
 212                                  * to ourselves in case we detect
 213                                  * broken rev-list, so that we can
 214                                  * leave the stream corrupted.  This
 215                                  * is unfortunate -- unpack-objects
 216                                  * would happily accept a valid pack
 217                                  * data with trailing garbage, so
 218                                  * appending garbage after we pass all
 219                                  * the pack data is not good enough to
 220                                  * signal breakage to downstream.
 221                                  */
 222                                 char *cp = data;
 223                                 ssize_t outsz = 0;
 224                                 if (0 <= buffered) {
 225                                         *cp++ = buffered;
 226                                         outsz++;
 227                                 }
 228                                 sz = read(pu_pipe[0], cp,
 229                                           sizeof(data) - outsz);
 230                                 if (0 < sz)
 231                                                 ;
 232                                 else if (sz == 0) {
 233                                         close(pu_pipe[0]);
 234                                         pu_pipe[0] = -1;
 235                                 }
 236                                 else
 237                                         goto fail;
 238                                 sz += outsz;
 239                                 if (1 < sz) {
 240                                         buffered = data[sz-1] & 0xFF;
 241                                         sz--;
 242                                 }
 243                                 else
 244                                         buffered = -1;
 245                                 sz = send_client_data(1, data, sz);
 246                                 if (sz < 0)
 247                                         goto fail;
 248                         }
 249                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 250                                 /* Status ready; we ship that in the side-band
 251                                  * or dump to the standard error.
 252                                  */
 253                                 sz = read(pe_pipe[0], progress,
 254                                           sizeof(progress));
 255                                 if (0 < sz)
 256                                         send_client_data(2, progress, sz);
 257                                 else if (sz == 0) {
 258                                         close(pe_pipe[0]);
 259                                         pe_pipe[0] = -1;
 260                                 }
 261                                 else
 262                                         goto fail;
 263                         }
 264                 }
 265
 266                 /* See if the children are still there */
 267                 if (pid_rev_list || pid_pack_objects) {
 268                         pid = waitpid(-1, &status, WNOHANG);
 269                         if (!pid)
 270                                 continue;
 271                         who = ((pid == pid_rev_list) ? "git-rev-list" :
 272                                (pid == pid_pack_objects) ? "git-pack-objects" :
 273                                NULL);
 274                         if (!who) {
 275                                 if (pid < 0) {
 276                                         error("git-upload-pack: %s",
 277                                               strerror(errno));
 278                                         goto fail;
 279                                 }
 280                                 error("git-upload-pack: we weren't "
 281                                       "waiting for %d", pid);
 282                                 continue;
 283                         }
 284                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
 285                                 error("git-upload-pack: %s died with error.",
 286                                       who);
 287                                 goto fail;
 288                         }
 289                         if (pid == pid_rev_list)
 290                                 pid_rev_list = 0;
 291                         if (pid == pid_pack_objects)
 292                                 pid_pack_objects = 0;
 293                         if (pid_rev_list || pid_pack_objects)
 294                                 continue;
 295                 }
 296
 297                 /* both died happily */
 298                 if (pollsize)
 299                         continue;
 300
 301                 /* flush the data */
 302                 if (0 <= buffered) {
 303                         data[0] = buffered;
 304                         sz = send_client_data(1, data, 1);
 305                         if (sz < 0)
 306                                 goto fail;
 307                         fprintf(stderr, "flushed.\n");
 308                 }
 309                 send_client_data(1, NULL, 0);
 310                 return;
 311         }
 312  fail:
 313         if (pid_pack_objects)
 314                 kill(pid_pack_objects, SIGKILL);
 315         if (pid_rev_list)
 316                 kill(pid_rev_list, SIGKILL);
 317         send_client_data(3, abort_msg, sizeof(abort_msg));
 318         die("git-upload-pack: %s", abort_msg);
 319 }
 320
 321 static int got_sha1(char *hex, unsigned char *sha1)
 322 {
 323         if (get_sha1_hex(hex, sha1))
 324                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 325         if (!has_sha1_file(sha1))
 326                 return 0;
 327         if (nr_has < MAX_HAS) {
 328                 struct object *o = lookup_object(sha1);
 329                 if (!(o && o->parsed))
 330                         o = parse_object(sha1);
 331                 if (!o)
 332                         die("oops (%s)", sha1_to_hex(sha1));
 333                 if (o->type == OBJ_COMMIT) {
 334                         struct commit_list *parents;
 335                         if (o->flags & THEY_HAVE)
 336                                 return 0;
 337                         o->flags |= THEY_HAVE;
 338                         for (parents = ((struct commit*)o)->parents;
 339                              parents;
 340                              parents = parents->next)
 341                                 parents->item->object.flags |= THEY_HAVE;
 342                 }
 343                 memcpy(has_sha1[nr_has++], sha1, 20);
 344         }
 345         return 1;
 346 }
 347
 348 static int get_common_commits(void)
 349 {
 350         static char line[1000];
 351         unsigned char sha1[20], last_sha1[20];
 352         int len;
 353
 354         track_object_refs = 0;
 355         save_commit_buffer = 0;
 356
 357         for(;;) {
 358                 len = packet_read_line(0, line, sizeof(line));
 359                 reset_timeout();
 360
 361                 if (!len) {
 362                         if (nr_has == 0 || multi_ack)
 363                                 packet_write(1, "NAK\n");
 364                         continue;
 365                 }
 366                 len = strip(line, len);
 367                 if (!strncmp(line, "have ", 5)) {
 368                         if (got_sha1(line+5, sha1) &&
 369                                         (multi_ack || nr_has == 1)) {
 370                                 if (nr_has >= MAX_HAS)
 371                                         multi_ack = 0;
 372                                 packet_write(1, "ACK %s%s\n",
 373                                         sha1_to_hex(sha1),
 374                                         multi_ack ?  " continue" : "");
 375                                 if (multi_ack)
 376                                         memcpy(last_sha1, sha1, 20);
 377                         }
 378                         continue;
 379                 }
 380                 if (!strcmp(line, "done")) {
 381                         if (nr_has > 0) {
 382                                 if (multi_ack)
 383                                         packet_write(1, "ACK %s\n",
 384                                                         sha1_to_hex(last_sha1));
 385                                 return 0;
 386                         }
 387                         packet_write(1, "NAK\n");
 388                         return -1;
 389                 }
 390                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 391         }
 392 }
 393
 394 static int receive_needs(void)
 395 {
 396         static char line[1000];
 397         int len, needs;
 398
 399         needs = 0;
 400         for (;;) {
 401                 struct object *o;
 402                 unsigned char dummy[20], *sha1_buf;
 403                 len = packet_read_line(0, line, sizeof(line));
 404                 reset_timeout();
 405                 if (!len)
 406                         return needs;
 407
 408                 sha1_buf = dummy;
 409                 if (needs == MAX_NEEDS) {
 410                         fprintf(stderr,
 411                                 "warning: supporting only a max of %d requests. "
 412                                 "sending everything instead.\n",
 413                                 MAX_NEEDS);
 414                 }
 415                 else if (needs < MAX_NEEDS)
 416                         sha1_buf = needs_sha1[needs];
 417
 418                 if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf))
 419                         die("git-upload-pack: protocol error, "
 420                             "expected to get sha, not '%s'", line);
 421                 if (strstr(line+45, "multi_ack"))
 422                         multi_ack = 1;
 423                 if (strstr(line+45, "thin-pack"))
 424                         use_thin_pack = 1;
 425                 if (strstr(line+45, "side-band"))
 426                         use_sideband = 1;
 427
 428                 /* We have sent all our refs already, and the other end
 429                  * should have chosen out of them; otherwise they are
 430                  * asking for nonsense.
 431                  *
 432                  * Hmph.  We may later want to allow "want" line that
 433                  * asks for something like "master~10" (symbolic)...
 434                  * would it make sense?  I don't know.
 435                  */
 436                 o = lookup_object(sha1_buf);
 437                 if (!o || !(o->flags & OUR_REF))
 438                         die("git-upload-pack: not our ref %s", line+5);
 439                 if (!(o->flags & WANTED)) {
 440                         o->flags |= WANTED;
 441                         needs++;
 442                 }
 443         }
 444 }
 445
 446 static int send_ref(const char *refname, const unsigned char *sha1)
 447 {
 448         static const char *capabilities = "multi_ack thin-pack side-band";
 449         struct object *o = parse_object(sha1);
 450
 451         if (!o)
 452                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 453
 454         if (capabilities)
 455                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 456                         0, capabilities);
 457         else
 458                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 459         capabilities = NULL;
 460         if (!(o->flags & OUR_REF)) {
 461                 o->flags |= OUR_REF;
 462                 nr_our_refs++;
 463         }
 464         if (o->type == OBJ_TAG) {
 465                 o = deref_tag(o, refname, 0);
 466                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 467         }
 468         return 0;
 469 }
 470
 471 static int upload_pack(void)
 472 {
 473         reset_timeout();
 474         head_ref(send_ref);
 475         for_each_ref(send_ref);
 476         packet_flush(1);
 477         nr_needs = receive_needs();
 478         if (!nr_needs)
 479                 return 0;
 480         get_common_commits();
 481         create_pack_file();
 482         return 0;
 483 }
 484
 485 int main(int argc, char **argv)
 486 {
 487         char *dir;
 488         int i;
 489         int strict = 0;
 490
 491         for (i = 1; i < argc; i++) {
 492                 char *arg = argv[i];
 493
 494                 if (arg[0] != '-')
 495                         break;
 496                 if (!strcmp(arg, "--strict")) {
 497                         strict = 1;
 498                         continue;
 499                 }
 500                 if (!strncmp(arg, "--timeout=", 10)) {
 501                         timeout = atoi(arg+10);
 502                         continue;
 503                 }
 504                 if (!strcmp(arg, "--")) {
 505                         i++;
 506                         break;
 507                 }
 508         }
 509
 510         if (i != argc-1)
 511                 usage(upload_pack_usage);
 512         dir = argv[i];
 513
 514         if (!enter_repo(dir, strict))
 515                 die("'%s': unable to chdir or not a git archive", dir);
 516
 517         upload_pack();
 518         return 0;
 519 }