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