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