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