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 "sideband.h"
   8 #include "tag.h"
   9 #include "object.h"
  10 #include "commit.h"
  11 #include "exec_cmd.h"
  12
  13 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  14
  15 #define THEY_HAVE (1U << 0)
  16 #define OUR_REF (1U << 1)
  17 #define WANTED (1U << 2)
  18 static int multi_ack, nr_our_refs;
  19 static int use_thin_pack;
  20 static struct object_array have_obj;
  21 static struct object_array want_obj;
  22 static unsigned int timeout;
  23 /* 0 for no sideband,
  24  * otherwise maximum packet size (up to 65520 bytes).
  25  */
  26 static int use_sideband;
  27
  28 static void reset_timeout(void)
  29 {
  30         alarm(timeout);
  31 }
  32
  33 static int strip(char *line, int len)
  34 {
  35         if (len && line[len-1] == '\n')
  36                 line[--len] = 0;
  37         return len;
  38 }
  39
  40 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
  41 {
  42         if (use_sideband)
  43                 return send_sideband(1, fd, data, sz, use_sideband);
  44         if (fd == 3)
  45                 /* emergency quit */
  46                 fd = 2;
  47         if (fd == 2) {
  48                 xwrite(fd, data, sz);
  49                 return sz;
  50         }
  51         return safe_write(fd, data, sz);
  52 }
  53
  54 static void create_pack_file(void)
  55 {
  56         /* Pipes between rev-list to pack-objects, pack-objects to us
  57          * and pack-objects error stream for progress bar.
  58          */
  59         int lp_pipe[2], pu_pipe[2], pe_pipe[2];
  60         pid_t pid_rev_list, pid_pack_objects;
  61         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
  62         char data[8193], progress[128];
  63         char abort_msg[] = "aborting due to possible repository "
  64                 "corruption on the remote side.";
  65         int buffered = -1;
  66
  67         if (pipe(lp_pipe) < 0)
  68                 die("git-upload-pack: unable to create pipe");
  69         pid_rev_list = fork();
  70         if (pid_rev_list < 0)
  71                 die("git-upload-pack: unable to fork git-rev-list");
  72
  73         if (!pid_rev_list) {
  74                 int i;
  75                 int args;
  76                 const char **argv;
  77                 const char **p;
  78                 char *buf;
  79
  80                 if (create_full_pack) {
  81                         args = 10;
  82                         use_thin_pack = 0; /* no point doing it */
  83                 }
  84                 else
  85                         args = have_obj.nr + want_obj.nr + 5;
  86                 p = xmalloc(args * sizeof(char *));
  87                 argv = (const char **) p;
  88                 buf = xmalloc(args * 45);
  89
  90                 dup2(lp_pipe[1], 1);
  91                 close(0);
  92                 close(lp_pipe[0]);
  93                 close(lp_pipe[1]);
  94                 *p++ = "rev-list";
  95                 *p++ = use_thin_pack ? "--objects-edge" : "--objects";
  96                 if (create_full_pack)
  97                         *p++ = "--all";
  98                 else {
  99                         for (i = 0; i < want_obj.nr; i++) {
 100                                 struct object *o = want_obj.objects[i].item;
 101                                 *p++ = buf;
 102                                 memcpy(buf, sha1_to_hex(o->sha1), 41);
 103                                 buf += 41;
 104                         }
 105                 }
 106                 if (!create_full_pack)
 107                         for (i = 0; i < have_obj.nr; i++) {
 108                                 struct object *o = have_obj.objects[i].item;
 109                                 *p++ = buf;
 110                                 *buf++ = '^';
 111                                 memcpy(buf, sha1_to_hex(o->sha1), 41);
 112                                 buf += 41;
 113                         }
 114                 *p++ = NULL;
 115                 execv_git_cmd(argv);
 116                 die("git-upload-pack: unable to exec git-rev-list");
 117         }
 118
 119         if (pipe(pu_pipe) < 0)
 120                 die("git-upload-pack: unable to create pipe");
 121         if (pipe(pe_pipe) < 0)
 122                 die("git-upload-pack: unable to create pipe");
 123         pid_pack_objects = fork();
 124         if (pid_pack_objects < 0) {
 125                 /* daemon sets things up to ignore TERM */
 126                 kill(pid_rev_list, SIGKILL);
 127                 die("git-upload-pack: unable to fork git-pack-objects");
 128         }
 129         if (!pid_pack_objects) {
 130                 dup2(lp_pipe[0], 0);
 131                 dup2(pu_pipe[1], 1);
 132                 dup2(pe_pipe[1], 2);
 133
 134                 close(lp_pipe[0]);
 135                 close(lp_pipe[1]);
 136                 close(pu_pipe[0]);
 137                 close(pu_pipe[1]);
 138                 close(pe_pipe[0]);
 139                 close(pe_pipe[1]);
 140                 execl_git_cmd("pack-objects", "--stdout", "--progress", NULL);
 141                 kill(pid_rev_list, SIGKILL);
 142                 die("git-upload-pack: unable to exec git-pack-objects");
 143         }
 144
 145         close(lp_pipe[0]);
 146         close(lp_pipe[1]);
 147
 148         /* We read from pe_pipe[0] to capture stderr output for
 149          * progress bar, and pu_pipe[0] to capture the pack data.
 150          */
 151         close(pe_pipe[1]);
 152         close(pu_pipe[1]);
 153
 154         while (1) {
 155                 const char *who;
 156                 struct pollfd pfd[2];
 157                 pid_t pid;
 158                 int status;
 159                 ssize_t sz;
 160                 int pe, pu, pollsize;
 161
 162                 reset_timeout();
 163
 164                 pollsize = 0;
 165                 pe = pu = -1;
 166
 167                 if (0 <= pu_pipe[0]) {
 168                         pfd[pollsize].fd = pu_pipe[0];
 169                         pfd[pollsize].events = POLLIN;
 170                         pu = pollsize;
 171                         pollsize++;
 172                 }
 173                 if (0 <= pe_pipe[0]) {
 174                         pfd[pollsize].fd = pe_pipe[0];
 175                         pfd[pollsize].events = POLLIN;
 176                         pe = pollsize;
 177                         pollsize++;
 178                 }
 179
 180                 if (pollsize) {
 181                         if (poll(pfd, pollsize, -1) < 0) {
 182                                 if (errno != EINTR) {
 183                                         error("poll failed, resuming: %s",
 184                                               strerror(errno));
 185                                         sleep(1);
 186                                 }
 187                                 continue;
 188                         }
 189                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
 190                                 /* Data ready; we keep the last byte
 191                                  * to ourselves in case we detect
 192                                  * broken rev-list, so that we can
 193                                  * leave the stream corrupted.  This
 194                                  * is unfortunate -- unpack-objects
 195                                  * would happily accept a valid pack
 196                                  * data with trailing garbage, so
 197                                  * appending garbage after we pass all
 198                                  * the pack data is not good enough to
 199                                  * signal breakage to downstream.
 200                                  */
 201                                 char *cp = data;
 202                                 ssize_t outsz = 0;
 203                                 if (0 <= buffered) {
 204                                         *cp++ = buffered;
 205                                         outsz++;
 206                                 }
 207                                 sz = read(pu_pipe[0], cp,
 208                                           sizeof(data) - outsz);
 209                                 if (0 < sz)
 210                                                 ;
 211                                 else if (sz == 0) {
 212                                         close(pu_pipe[0]);
 213                                         pu_pipe[0] = -1;
 214                                 }
 215                                 else
 216                                         goto fail;
 217                                 sz += outsz;
 218                                 if (1 < sz) {
 219                                         buffered = data[sz-1] & 0xFF;
 220                                         sz--;
 221                                 }
 222                                 else
 223                                         buffered = -1;
 224                                 sz = send_client_data(1, data, sz);
 225                                 if (sz < 0)
 226                                         goto fail;
 227                         }
 228                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
 229                                 /* Status ready; we ship that in the side-band
 230                                  * or dump to the standard error.
 231                                  */
 232                                 sz = read(pe_pipe[0], progress,
 233                                           sizeof(progress));
 234                                 if (0 < sz)
 235                                         send_client_data(2, progress, sz);
 236                                 else if (sz == 0) {
 237                                         close(pe_pipe[0]);
 238                                         pe_pipe[0] = -1;
 239                                 }
 240                                 else
 241                                         goto fail;
 242                         }
 243                 }
 244
 245                 /* See if the children are still there */
 246                 if (pid_rev_list || pid_pack_objects) {
 247                         pid = waitpid(-1, &status, WNOHANG);
 248                         if (!pid)
 249                                 continue;
 250                         who = ((pid == pid_rev_list) ? "git-rev-list" :
 251                                (pid == pid_pack_objects) ? "git-pack-objects" :
 252                                NULL);
 253                         if (!who) {
 254                                 if (pid < 0) {
 255                                         error("git-upload-pack: %s",
 256                                               strerror(errno));
 257                                         goto fail;
 258                                 }
 259                                 error("git-upload-pack: we weren't "
 260                                       "waiting for %d", pid);
 261                                 continue;
 262                         }
 263                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
 264                                 error("git-upload-pack: %s died with error.",
 265                                       who);
 266                                 goto fail;
 267                         }
 268                         if (pid == pid_rev_list)
 269                                 pid_rev_list = 0;
 270                         if (pid == pid_pack_objects)
 271                                 pid_pack_objects = 0;
 272                         if (pid_rev_list || pid_pack_objects)
 273                                 continue;
 274                 }
 275
 276                 /* both died happily */
 277                 if (pollsize)
 278                         continue;
 279
 280                 /* flush the data */
 281                 if (0 <= buffered) {
 282                         data[0] = buffered;
 283                         sz = send_client_data(1, data, 1);
 284                         if (sz < 0)
 285                                 goto fail;
 286                         fprintf(stderr, "flushed.\n");
 287                 }
 288                 if (use_sideband)
 289                         packet_flush(1);
 290                 return;
 291         }
 292  fail:
 293         if (pid_pack_objects)
 294                 kill(pid_pack_objects, SIGKILL);
 295         if (pid_rev_list)
 296                 kill(pid_rev_list, SIGKILL);
 297         send_client_data(3, abort_msg, sizeof(abort_msg));
 298         die("git-upload-pack: %s", abort_msg);
 299 }
 300
 301 static int got_sha1(char *hex, unsigned char *sha1)
 302 {
 303         struct object *o;
 304
 305         if (get_sha1_hex(hex, sha1))
 306                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 307         if (!has_sha1_file(sha1))
 308                 return 0;
 309
 310         o = lookup_object(sha1);
 311         if (!(o && o->parsed))
 312                 o = parse_object(sha1);
 313         if (!o)
 314                 die("oops (%s)", sha1_to_hex(sha1));
 315         if (o->type == OBJ_COMMIT) {
 316                 struct commit_list *parents;
 317                 if (o->flags & THEY_HAVE)
 318                         return 0;
 319                 o->flags |= THEY_HAVE;
 320                 for (parents = ((struct commit*)o)->parents;
 321                      parents;
 322                      parents = parents->next)
 323                         parents->item->object.flags |= THEY_HAVE;
 324         }
 325         add_object_array(o, NULL, &have_obj);
 326         return 1;
 327 }
 328
 329 static int get_common_commits(void)
 330 {
 331         static char line[1000];
 332         unsigned char sha1[20];
 333         char hex[41], last_hex[41];
 334         int len;
 335
 336         track_object_refs = 0;
 337         save_commit_buffer = 0;
 338
 339         for(;;) {
 340                 len = packet_read_line(0, line, sizeof(line));
 341                 reset_timeout();
 342
 343                 if (!len) {
 344                         if (have_obj.nr == 0 || multi_ack)
 345                                 packet_write(1, "NAK\n");
 346                         continue;
 347                 }
 348                 len = strip(line, len);
 349                 if (!strncmp(line, "have ", 5)) {
 350                         if (got_sha1(line+5, sha1)) {
 351                                 memcpy(hex, sha1_to_hex(sha1), 41);
 352                                 if (multi_ack) {
 353                                         const char *msg = "ACK %s continue\n";
 354                                         packet_write(1, msg, hex);
 355                                         memcpy(last_hex, hex, 41);
 356                                 }
 357                                 else if (have_obj.nr == 1)
 358                                         packet_write(1, "ACK %s\n", hex);
 359                         }
 360                         continue;
 361                 }
 362                 if (!strcmp(line, "done")) {
 363                         if (have_obj.nr > 0) {
 364                                 if (multi_ack)
 365                                         packet_write(1, "ACK %s\n", last_hex);
 366                                 return 0;
 367                         }
 368                         packet_write(1, "NAK\n");
 369                         return -1;
 370                 }
 371                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
 372         }
 373 }
 374
 375 static void receive_needs(void)
 376 {
 377         static char line[1000];
 378         int len;
 379
 380         for (;;) {
 381                 struct object *o;
 382                 unsigned char sha1_buf[20];
 383                 len = packet_read_line(0, line, sizeof(line));
 384                 reset_timeout();
 385                 if (!len)
 386                         return;
 387
 388                 if (strncmp("want ", line, 5) ||
 389                     get_sha1_hex(line+5, sha1_buf))
 390                         die("git-upload-pack: protocol error, "
 391                             "expected to get sha, not '%s'", line);
 392                 if (strstr(line+45, "multi_ack"))
 393                         multi_ack = 1;
 394                 if (strstr(line+45, "thin-pack"))
 395                         use_thin_pack = 1;
 396                 if (strstr(line+45, "side-band-64k"))
 397                         use_sideband = LARGE_PACKET_MAX;
 398                 else if (strstr(line+45, "side-band"))
 399                         use_sideband = DEFAULT_PACKET_MAX;
 400
 401                 /* We have sent all our refs already, and the other end
 402                  * should have chosen out of them; otherwise they are
 403                  * asking for nonsense.
 404                  *
 405                  * Hmph.  We may later want to allow "want" line that
 406                  * asks for something like "master~10" (symbolic)...
 407                  * would it make sense?  I don't know.
 408                  */
 409                 o = lookup_object(sha1_buf);
 410                 if (!o || !(o->flags & OUR_REF))
 411                         die("git-upload-pack: not our ref %s", line+5);
 412                 if (!(o->flags & WANTED)) {
 413                         o->flags |= WANTED;
 414                         add_object_array(o, NULL, &want_obj);
 415                 }
 416         }
 417 }
 418
 419 static int send_ref(const char *refname, const unsigned char *sha1)
 420 {
 421         static const char *capabilities = "multi_ack thin-pack side-band side-band-64k";
 422         struct object *o = parse_object(sha1);
 423
 424         if (!o)
 425                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 426
 427         if (capabilities)
 428                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 429                         0, capabilities);
 430         else
 431                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 432         capabilities = NULL;
 433         if (!(o->flags & OUR_REF)) {
 434                 o->flags |= OUR_REF;
 435                 nr_our_refs++;
 436         }
 437         if (o->type == OBJ_TAG) {
 438                 o = deref_tag(o, refname, 0);
 439                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 440         }
 441         return 0;
 442 }
 443
 444 static void upload_pack(void)
 445 {
 446         reset_timeout();
 447         head_ref(send_ref);
 448         for_each_ref(send_ref);
 449         packet_flush(1);
 450         receive_needs();
 451         if (want_obj.nr) {
 452                 get_common_commits();
 453                 create_pack_file();
 454         }
 455 }
 456
 457 int main(int argc, char **argv)
 458 {
 459         char *dir;
 460         int i;
 461         int strict = 0;
 462
 463         for (i = 1; i < argc; i++) {
 464                 char *arg = argv[i];
 465
 466                 if (arg[0] != '-')
 467                         break;
 468                 if (!strcmp(arg, "--strict")) {
 469                         strict = 1;
 470                         continue;
 471                 }
 472                 if (!strncmp(arg, "--timeout=", 10)) {
 473                         timeout = atoi(arg+10);
 474                         continue;
 475                 }
 476                 if (!strcmp(arg, "--")) {
 477                         i++;
 478                         break;
 479                 }
 480         }
 481
 482         if (i != argc-1)
 483                 usage(upload_pack_usage);
 484         dir = argv[i];
 485
 486         if (!enter_repo(dir, strict))
 487                 die("'%s': unable to chdir or not a git archive", dir);
 488
 489         upload_pack();
 490         return 0;
 491 }