daemon.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3 #include "exec_cmd.h"
   4 #include "run-command.h"
   5 #include "strbuf.h"
   6 #include "string-list.h"
   7
   8 #ifndef HOST_NAME_MAX
   9 #define HOST_NAME_MAX 256
  10 #endif
  11
  12 #ifdef NO_INITGROUPS
  13 #define initgroups(x, y) (0) /* nothing */
  14 #endif
  15
  16 static int log_syslog;
  17 static int verbose;
  18 static int reuseaddr;
  19 static int informative_errors;
  20
  21 static const char daemon_usage[] =
  22 "git daemon [--verbose] [--syslog] [--export-all]\n"
  23 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  24 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  25 "           [--user-path | --user-path=<path>]\n"
  26 "           [--interpolated-path=<path>]\n"
  27 "           [--reuseaddr] [--pid-file=<file>]\n"
  28 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  29 "           [--access-hook=<path>]\n"
  30 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  31 "                      [--detach] [--user=<user> [--group=<group>]]\n"
  32 "           [<directory>...]";
  33
  34 /* List of acceptable pathname prefixes */
  35 static char **ok_paths;
  36 static int strict_paths;
  37
  38 /* If this is set, git-daemon-export-ok is not required */
  39 static int export_all_trees;
  40
  41 /* Take all paths relative to this one if non-NULL */
  42 static char *base_path;
  43 static char *interpolated_path;
  44 static int base_path_relaxed;
  45
  46 /* Flag indicating client sent extra args. */
  47 static int saw_extended_args;
  48
  49 /* If defined, ~user notation is allowed and the string is inserted
  50  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  51  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  52  */
  53 static const char *user_path;
  54
  55 /* Timeout, and initial timeout */
  56 static unsigned int timeout;
  57 static unsigned int init_timeout;
  58
  59 static char *hostname;
  60 static char *canon_hostname;
  61 static char *ip_address;
  62 static char *tcp_port;
  63
  64 static void logreport(int priority, const char *err, va_list params)
  65 {
  66         if (log_syslog) {
  67                 char buf[1024];
  68                 vsnprintf(buf, sizeof(buf), err, params);
  69                 syslog(priority, "%s", buf);
  70         } else {
  71                 /*
  72                  * Since stderr is set to buffered mode, the
  73                  * logging of different processes will not overlap
  74                  * unless they overflow the (rather big) buffers.
  75                  */
  76                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  77                 vfprintf(stderr, err, params);
  78                 fputc('\n', stderr);
  79                 fflush(stderr);
  80         }
  81 }
  82
  83 __attribute__((format (printf, 1, 2)))
  84 static void logerror(const char *err, ...)
  85 {
  86         va_list params;
  87         va_start(params, err);
  88         logreport(LOG_ERR, err, params);
  89         va_end(params);
  90 }
  91
  92 __attribute__((format (printf, 1, 2)))
  93 static void loginfo(const char *err, ...)
  94 {
  95         va_list params;
  96         if (!verbose)
  97                 return;
  98         va_start(params, err);
  99         logreport(LOG_INFO, err, params);
 100         va_end(params);
 101 }
 102
 103 static void NORETURN daemon_die(const char *err, va_list params)
 104 {
 105         logreport(LOG_ERR, err, params);
 106         exit(1);
 107 }
 108
 109 static const char *path_ok(char *directory)
 110 {
 111         static char rpath[PATH_MAX];
 112         static char interp_path[PATH_MAX];
 113         const char *path;
 114         char *dir;
 115
 116         dir = directory;
 117
 118         if (daemon_avoid_alias(dir)) {
 119                 logerror("'%s': aliased", dir);
 120                 return NULL;
 121         }
 122
 123         if (*dir == '~') {
 124                 if (!user_path) {
 125                         logerror("'%s': User-path not allowed", dir);
 126                         return NULL;
 127                 }
 128                 if (*user_path) {
 129                         /* Got either "~alice" or "~alice/foo";
 130                          * rewrite them to "~alice/%s" or
 131                          * "~alice/%s/foo".
 132                          */
 133                         int namlen, restlen = strlen(dir);
 134                         char *slash = strchr(dir, '/');
 135                         if (!slash)
 136                                 slash = dir + restlen;
 137                         namlen = slash - dir;
 138                         restlen -= namlen;
 139                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 140                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 141                                  namlen, dir, user_path, restlen, slash);
 142                         dir = rpath;
 143                 }
 144         }
 145         else if (interpolated_path && saw_extended_args) {
 146                 struct strbuf expanded_path = STRBUF_INIT;
 147                 struct strbuf_expand_dict_entry dict[6];
 148
 149                 dict[0].placeholder = "H"; dict[0].value = hostname;
 150                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 151                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
 152                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
 153                 dict[4].placeholder = "D"; dict[4].value = directory;
 154                 dict[5].placeholder = NULL; dict[5].value = NULL;
 155                 if (*dir != '/') {
 156                         /* Allow only absolute */
 157                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 158                         return NULL;
 159                 }
 160
 161                 strbuf_expand(&expanded_path, interpolated_path,
 162                                 strbuf_expand_dict_cb, &dict);
 163                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 164                 strbuf_release(&expanded_path);
 165                 loginfo("Interpolated dir '%s'", interp_path);
 166
 167                 dir = interp_path;
 168         }
 169         else if (base_path) {
 170                 if (*dir != '/') {
 171                         /* Allow only absolute */
 172                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 173                         return NULL;
 174                 }
 175                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 176                 dir = rpath;
 177         }
 178
 179         path = enter_repo(dir, strict_paths);
 180         if (!path && base_path && base_path_relaxed) {
 181                 /*
 182                  * if we fail and base_path_relaxed is enabled, try without
 183                  * prefixing the base path
 184                  */
 185                 dir = directory;
 186                 path = enter_repo(dir, strict_paths);
 187         }
 188
 189         if (!path) {
 190                 logerror("'%s' does not appear to be a git repository", dir);
 191                 return NULL;
 192         }
 193
 194         if ( ok_paths && *ok_paths ) {
 195                 char **pp;
 196                 int pathlen = strlen(path);
 197
 198                 /* The validation is done on the paths after enter_repo
 199                  * appends optional {.git,.git/.git} and friends, but
 200                  * it does not use getcwd().  So if your /pub is
 201                  * a symlink to /mnt/pub, you can whitelist /pub and
 202                  * do not have to say /mnt/pub.
 203                  * Do not say /pub/.
 204                  */
 205                 for ( pp = ok_paths ; *pp ; pp++ ) {
 206                         int len = strlen(*pp);
 207                         if (len <= pathlen &&
 208                             !memcmp(*pp, path, len) &&
 209                             (path[len] == '\0' ||
 210                              (!strict_paths && path[len] == '/')))
 211                                 return path;
 212                 }
 213         }
 214         else {
 215                 /* be backwards compatible */
 216                 if (!strict_paths)
 217                         return path;
 218         }
 219
 220         logerror("'%s': not in whitelist", path);
 221         return NULL;            /* Fallthrough. Deny by default */
 222 }
 223
 224 typedef int (*daemon_service_fn)(void);
 225 struct daemon_service {
 226         const char *name;
 227         const char *config_name;
 228         daemon_service_fn fn;
 229         int enabled;
 230         int overridable;
 231 };
 232
 233 static struct daemon_service *service_looking_at;
 234 static int service_enabled;
 235
 236 static int git_daemon_config(const char *var, const char *value, void *cb)
 237 {
 238         if (!prefixcmp(var, "daemon.") &&
 239             !strcmp(var + 7, service_looking_at->config_name)) {
 240                 service_enabled = git_config_bool(var, value);
 241                 return 0;
 242         }
 243
 244         /* we are not interested in parsing any other configuration here */
 245         return 0;
 246 }
 247
 248 static int daemon_error(const char *dir, const char *msg)
 249 {
 250         if (!informative_errors)
 251                 msg = "access denied or repository not exported";
 252         packet_write(1, "ERR %s: %s", msg, dir);
 253         return -1;
 254 }
 255
 256 static char *access_hook;
 257
 258 static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 259 {
 260         struct child_process child;
 261         struct strbuf buf = STRBUF_INIT;
 262         const char *argv[8];
 263         const char **arg = argv;
 264         char *eol;
 265         int seen_errors = 0;
 266
 267 #define STRARG(x) ((x) ? (x) : "")
 268         *arg++ = access_hook;
 269         *arg++ = service->name;
 270         *arg++ = path;
 271         *arg++ = STRARG(hostname);
 272         *arg++ = STRARG(canon_hostname);
 273         *arg++ = STRARG(ip_address);
 274         *arg++ = STRARG(tcp_port);
 275         *arg = NULL;
 276 #undef STRARG
 277
 278         memset(&child, 0, sizeof(child));
 279         child.use_shell = 1;
 280         child.argv = argv;
 281         child.no_stdin = 1;
 282         child.no_stderr = 1;
 283         child.out = -1;
 284         if (start_command(&child)) {
 285                 logerror("daemon access hook '%s' failed to start",
 286                          access_hook);
 287                 goto error_return;
 288         }
 289         if (strbuf_read(&buf, child.out, 0) < 0) {
 290                 logerror("failed to read from pipe to daemon access hook '%s'",
 291                          access_hook);
 292                 strbuf_reset(&buf);
 293                 seen_errors = 1;
 294         }
 295         if (close(child.out) < 0) {
 296                 logerror("failed to close pipe to daemon access hook '%s'",
 297                          access_hook);
 298                 seen_errors = 1;
 299         }
 300         if (finish_command(&child))
 301                 seen_errors = 1;
 302
 303         if (!seen_errors) {
 304                 strbuf_release(&buf);
 305                 return 0;
 306         }
 307
 308 error_return:
 309         strbuf_ltrim(&buf);
 310         if (!buf.len)
 311                 strbuf_addstr(&buf, "service rejected");
 312         eol = strchr(buf.buf, '\n');
 313         if (eol)
 314                 *eol = '\0';
 315         errno = EACCES;
 316         daemon_error(dir, buf.buf);
 317         strbuf_release(&buf);
 318         return -1;
 319 }
 320
 321 static int run_service(char *dir, struct daemon_service *service)
 322 {
 323         const char *path;
 324         int enabled = service->enabled;
 325
 326         loginfo("Request %s for '%s'", service->name, dir);
 327
 328         if (!enabled && !service->overridable) {
 329                 logerror("'%s': service not enabled.", service->name);
 330                 errno = EACCES;
 331                 return daemon_error(dir, "service not enabled");
 332         }
 333
 334         if (!(path = path_ok(dir)))
 335                 return daemon_error(dir, "no such repository");
 336
 337         /*
 338          * Security on the cheap.
 339          *
 340          * We want a readable HEAD, usable "objects" directory, and
 341          * a "git-daemon-export-ok" flag that says that the other side
 342          * is ok with us doing this.
 343          *
 344          * path_ok() uses enter_repo() and does whitelist checking.
 345          * We only need to make sure the repository is exported.
 346          */
 347
 348         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 349                 logerror("'%s': repository not exported.", path);
 350                 errno = EACCES;
 351                 return daemon_error(dir, "repository not exported");
 352         }
 353
 354         if (service->overridable) {
 355                 service_looking_at = service;
 356                 service_enabled = -1;
 357                 git_config(git_daemon_config, NULL);
 358                 if (0 <= service_enabled)
 359                         enabled = service_enabled;
 360         }
 361         if (!enabled) {
 362                 logerror("'%s': service not enabled for '%s'",
 363                          service->name, path);
 364                 errno = EACCES;
 365                 return daemon_error(dir, "service not enabled");
 366         }
 367
 368         /*
 369          * Optionally, a hook can choose to deny access to the
 370          * repository depending on the phase of the moon.
 371          */
 372         if (access_hook && run_access_hook(service, dir, path))
 373                 return -1;
 374
 375         /*
 376          * We'll ignore SIGTERM from now on, we have a
 377          * good client.
 378          */
 379         signal(SIGTERM, SIG_IGN);
 380
 381         return service->fn();
 382 }
 383
 384 static void copy_to_log(int fd)
 385 {
 386         struct strbuf line = STRBUF_INIT;
 387         FILE *fp;
 388
 389         fp = fdopen(fd, "r");
 390         if (fp == NULL) {
 391                 logerror("fdopen of error channel failed");
 392                 close(fd);
 393                 return;
 394         }
 395
 396         while (strbuf_getline(&line, fp, '\n') != EOF) {
 397                 logerror("%s", line.buf);
 398                 strbuf_setlen(&line, 0);
 399         }
 400
 401         strbuf_release(&line);
 402         fclose(fp);
 403 }
 404
 405 static int run_service_command(const char **argv)
 406 {
 407         struct child_process cld;
 408
 409         memset(&cld, 0, sizeof(cld));
 410         cld.argv = argv;
 411         cld.git_cmd = 1;
 412         cld.err = -1;
 413         if (start_command(&cld))
 414                 return -1;
 415
 416         close(0);
 417         close(1);
 418
 419         copy_to_log(cld.err);
 420
 421         return finish_command(&cld);
 422 }
 423
 424 static int upload_pack(void)
 425 {
 426         /* Timeout as string */
 427         char timeout_buf[64];
 428         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 429
 430         argv[2] = timeout_buf;
 431
 432         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 433         return run_service_command(argv);
 434 }
 435
 436 static int upload_archive(void)
 437 {
 438         static const char *argv[] = { "upload-archive", ".", NULL };
 439         return run_service_command(argv);
 440 }
 441
 442 static int receive_pack(void)
 443 {
 444         static const char *argv[] = { "receive-pack", ".", NULL };
 445         return run_service_command(argv);
 446 }
 447
 448 static struct daemon_service daemon_service[] = {
 449         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 450         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 451         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 452 };
 453
 454 static void enable_service(const char *name, int ena)
 455 {
 456         int i;
 457         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 458                 if (!strcmp(daemon_service[i].name, name)) {
 459                         daemon_service[i].enabled = ena;
 460                         return;
 461                 }
 462         }
 463         die("No such service %s", name);
 464 }
 465
 466 static void make_service_overridable(const char *name, int ena)
 467 {
 468         int i;
 469         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 470                 if (!strcmp(daemon_service[i].name, name)) {
 471                         daemon_service[i].overridable = ena;
 472                         return;
 473                 }
 474         }
 475         die("No such service %s", name);
 476 }
 477
 478 static char *xstrdup_tolower(const char *str)
 479 {
 480         char *p, *dup = xstrdup(str);
 481         for (p = dup; *p; p++)
 482                 *p = tolower(*p);
 483         return dup;
 484 }
 485
 486 static void parse_host_and_port(char *hostport, char **host,
 487         char **port)
 488 {
 489         if (*hostport == '[') {
 490                 char *end;
 491
 492                 end = strchr(hostport, ']');
 493                 if (!end)
 494                         die("Invalid request ('[' without ']')");
 495                 *end = '\0';
 496                 *host = hostport + 1;
 497                 if (!end[1])
 498                         *port = NULL;
 499                 else if (end[1] == ':')
 500                         *port = end + 2;
 501                 else
 502                         die("Garbage after end of host part");
 503         } else {
 504                 *host = hostport;
 505                 *port = strrchr(hostport, ':');
 506                 if (*port) {
 507                         **port = '\0';
 508                         ++*port;
 509                 }
 510         }
 511 }
 512
 513 /*
 514  * Read the host as supplied by the client connection.
 515  */
 516 static void parse_host_arg(char *extra_args, int buflen)
 517 {
 518         char *val;
 519         int vallen;
 520         char *end = extra_args + buflen;
 521
 522         if (extra_args < end && *extra_args) {
 523                 saw_extended_args = 1;
 524                 if (strncasecmp("host=", extra_args, 5) == 0) {
 525                         val = extra_args + 5;
 526                         vallen = strlen(val) + 1;
 527                         if (*val) {
 528                                 /* Split <host>:<port> at colon. */
 529                                 char *host;
 530                                 char *port;
 531                                 parse_host_and_port(val, &host, &port);
 532                                 if (port) {
 533                                         free(tcp_port);
 534                                         tcp_port = xstrdup(port);
 535                                 }
 536                                 free(hostname);
 537                                 hostname = xstrdup_tolower(host);
 538                         }
 539
 540                         /* On to the next one */
 541                         extra_args = val + vallen;
 542                 }
 543                 if (extra_args < end && *extra_args)
 544                         die("Invalid request");
 545         }
 546
 547         /*
 548          * Locate canonical hostname and its IP address.
 549          */
 550         if (hostname) {
 551 #ifndef NO_IPV6
 552                 struct addrinfo hints;
 553                 struct addrinfo *ai;
 554                 int gai;
 555                 static char addrbuf[HOST_NAME_MAX + 1];
 556
 557                 memset(&hints, 0, sizeof(hints));
 558                 hints.ai_flags = AI_CANONNAME;
 559
 560                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 561                 if (!gai) {
 562                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 563
 564                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 565                                   addrbuf, sizeof(addrbuf));
 566                         free(ip_address);
 567                         ip_address = xstrdup(addrbuf);
 568
 569                         free(canon_hostname);
 570                         canon_hostname = xstrdup(ai->ai_canonname ?
 571                                                  ai->ai_canonname : ip_address);
 572
 573                         freeaddrinfo(ai);
 574                 }
 575 #else
 576                 struct hostent *hent;
 577                 struct sockaddr_in sa;
 578                 char **ap;
 579                 static char addrbuf[HOST_NAME_MAX + 1];
 580
 581                 hent = gethostbyname(hostname);
 582                 if (hent) {
 583                         ap = hent->h_addr_list;
 584                         memset(&sa, 0, sizeof sa);
 585                         sa.sin_family = hent->h_addrtype;
 586                         sa.sin_port = htons(0);
 587                         memcpy(&sa.sin_addr, *ap, hent->h_length);
 588
 589                         inet_ntop(hent->h_addrtype, &sa.sin_addr,
 590                                   addrbuf, sizeof(addrbuf));
 591
 592                         free(canon_hostname);
 593                         canon_hostname = xstrdup(hent->h_name);
 594                         free(ip_address);
 595                         ip_address = xstrdup(addrbuf);
 596                 }
 597 #endif
 598         }
 599 }
 600
 601
 602 static int execute(void)
 603 {
 604         char *line = packet_buffer;
 605         int pktlen, len, i;
 606         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 607
 608         if (addr)
 609                 loginfo("Connection from %s:%s", addr, port);
 610
 611         alarm(init_timeout ? init_timeout : timeout);
 612         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 613         alarm(0);
 614
 615         len = strlen(line);
 616         if (pktlen != len)
 617                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 618                         (int) pktlen - len,
 619                         (int) pktlen - len, line + len + 1);
 620         if (len && line[len-1] == '\n') {
 621                 line[--len] = 0;
 622                 pktlen--;
 623         }
 624
 625         free(hostname);
 626         free(canon_hostname);
 627         free(ip_address);
 628         free(tcp_port);
 629         hostname = canon_hostname = ip_address = tcp_port = NULL;
 630
 631         if (len != pktlen)
 632                 parse_host_arg(line + len + 1, pktlen - len - 1);
 633
 634         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 635                 struct daemon_service *s = &(daemon_service[i]);
 636                 int namelen = strlen(s->name);
 637                 if (!prefixcmp(line, "git-") &&
 638                     !strncmp(s->name, line + 4, namelen) &&
 639                     line[namelen + 4] == ' ') {
 640                         /*
 641                          * Note: The directory here is probably context sensitive,
 642                          * and might depend on the actual service being performed.
 643                          */
 644                         return run_service(line + namelen + 5, s);
 645                 }
 646         }
 647
 648         logerror("Protocol error: '%s'", line);
 649         return -1;
 650 }
 651
 652 static int addrcmp(const struct sockaddr_storage *s1,
 653     const struct sockaddr_storage *s2)
 654 {
 655         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 656         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 657
 658         if (sa1->sa_family != sa2->sa_family)
 659                 return sa1->sa_family - sa2->sa_family;
 660         if (sa1->sa_family == AF_INET)
 661                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 662                     &((struct sockaddr_in *)s2)->sin_addr,
 663                     sizeof(struct in_addr));
 664 #ifndef NO_IPV6
 665         if (sa1->sa_family == AF_INET6)
 666                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 667                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 668                     sizeof(struct in6_addr));
 669 #endif
 670         return 0;
 671 }
 672
 673 static int max_connections = 32;
 674
 675 static unsigned int live_children;
 676
 677 static struct child {
 678         struct child *next;
 679         struct child_process cld;
 680         struct sockaddr_storage address;
 681 } *firstborn;
 682
 683 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 684 {
 685         struct child *newborn, **cradle;
 686
 687         newborn = xcalloc(1, sizeof(*newborn));
 688         live_children++;
 689         memcpy(&newborn->cld, cld, sizeof(*cld));
 690         memcpy(&newborn->address, addr, addrlen);
 691         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 692                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 693                         break;
 694         newborn->next = *cradle;
 695         *cradle = newborn;
 696 }
 697
 698 /*
 699  * This gets called if the number of connections grows
 700  * past "max_connections".
 701  *
 702  * We kill the newest connection from a duplicate IP.
 703  */
 704 static void kill_some_child(void)
 705 {
 706         const struct child *blanket, *next;
 707
 708         if (!(blanket = firstborn))
 709                 return;
 710
 711         for (; (next = blanket->next); blanket = next)
 712                 if (!addrcmp(&blanket->address, &next->address)) {
 713                         kill(blanket->cld.pid, SIGTERM);
 714                         break;
 715                 }
 716 }
 717
 718 static void check_dead_children(void)
 719 {
 720         int status;
 721         pid_t pid;
 722
 723         struct child **cradle, *blanket;
 724         for (cradle = &firstborn; (blanket = *cradle);)
 725                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 726                         const char *dead = "";
 727                         if (status)
 728                                 dead = " (with error)";
 729                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 730
 731                         /* remove the child */
 732                         *cradle = blanket->next;
 733                         live_children--;
 734                         free(blanket);
 735                 } else
 736                         cradle = &blanket->next;
 737 }
 738
 739 static char **cld_argv;
 740 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 741 {
 742         struct child_process cld = { NULL };
 743         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 744         char *env[] = { addrbuf, portbuf, NULL };
 745
 746         if (max_connections && live_children >= max_connections) {
 747                 kill_some_child();
 748                 sleep(1);  /* give it some time to die */
 749                 check_dead_children();
 750                 if (live_children >= max_connections) {
 751                         close(incoming);
 752                         logerror("Too many children, dropping connection");
 753                         return;
 754                 }
 755         }
 756
 757         if (addr->sa_family == AF_INET) {
 758                 struct sockaddr_in *sin_addr = (void *) addr;
 759                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 760                     sizeof(addrbuf) - 12);
 761                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 762                     ntohs(sin_addr->sin_port));
 763 #ifndef NO_IPV6
 764         } else if (addr->sa_family == AF_INET6) {
 765                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 766
 767                 char *buf = addrbuf + 12;
 768                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 769                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 770                     sizeof(addrbuf) - 13);
 771                 strcat(buf, "]");
 772
 773                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 774                     ntohs(sin6_addr->sin6_port));
 775 #endif
 776         }
 777
 778         cld.env = (const char **)env;
 779         cld.argv = (const char **)cld_argv;
 780         cld.in = incoming;
 781         cld.out = dup(incoming);
 782
 783         if (start_command(&cld))
 784                 logerror("unable to fork");
 785         else
 786                 add_child(&cld, addr, addrlen);
 787         close(incoming);
 788 }
 789
 790 static void child_handler(int signo)
 791 {
 792         /*
 793          * Otherwise empty handler because systemcalls will get interrupted
 794          * upon signal receipt
 795          * SysV needs the handler to be rearmed
 796          */
 797         signal(SIGCHLD, child_handler);
 798 }
 799
 800 static int set_reuse_addr(int sockfd)
 801 {
 802         int on = 1;
 803
 804         if (!reuseaddr)
 805                 return 0;
 806         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 807                           &on, sizeof(on));
 808 }
 809
 810 struct socketlist {
 811         int *list;
 812         size_t nr;
 813         size_t alloc;
 814 };
 815
 816 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 817 {
 818 #ifdef NO_IPV6
 819         static char ip[INET_ADDRSTRLEN];
 820 #else
 821         static char ip[INET6_ADDRSTRLEN];
 822 #endif
 823
 824         switch (family) {
 825 #ifndef NO_IPV6
 826         case AF_INET6:
 827                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 828                 break;
 829 #endif
 830         case AF_INET:
 831                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 832                 break;
 833         default:
 834                 strcpy(ip, "<unknown>");
 835         }
 836         return ip;
 837 }
 838
 839 #ifndef NO_IPV6
 840
 841 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 842 {
 843         int socknum = 0;
 844         int maxfd = -1;
 845         char pbuf[NI_MAXSERV];
 846         struct addrinfo hints, *ai0, *ai;
 847         int gai;
 848         long flags;
 849
 850         sprintf(pbuf, "%d", listen_port);
 851         memset(&hints, 0, sizeof(hints));
 852         hints.ai_family = AF_UNSPEC;
 853         hints.ai_socktype = SOCK_STREAM;
 854         hints.ai_protocol = IPPROTO_TCP;
 855         hints.ai_flags = AI_PASSIVE;
 856
 857         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 858         if (gai) {
 859                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 860                 return 0;
 861         }
 862
 863         for (ai = ai0; ai; ai = ai->ai_next) {
 864                 int sockfd;
 865
 866                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 867                 if (sockfd < 0)
 868                         continue;
 869                 if (sockfd >= FD_SETSIZE) {
 870                         logerror("Socket descriptor too large");
 871                         close(sockfd);
 872                         continue;
 873                 }
 874
 875 #ifdef IPV6_V6ONLY
 876                 if (ai->ai_family == AF_INET6) {
 877                         int on = 1;
 878                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 879                                    &on, sizeof(on));
 880                         /* Note: error is not fatal */
 881                 }
 882 #endif
 883
 884                 if (set_reuse_addr(sockfd)) {
 885                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 886                         close(sockfd);
 887                         continue;
 888                 }
 889
 890                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 891                         logerror("Could not bind to %s: %s",
 892                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 893                                  strerror(errno));
 894                         close(sockfd);
 895                         continue;       /* not fatal */
 896                 }
 897                 if (listen(sockfd, 5) < 0) {
 898                         logerror("Could not listen to %s: %s",
 899                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 900                                  strerror(errno));
 901                         close(sockfd);
 902                         continue;       /* not fatal */
 903                 }
 904
 905                 flags = fcntl(sockfd, F_GETFD, 0);
 906                 if (flags >= 0)
 907                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 908
 909                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 910                 socklist->list[socklist->nr++] = sockfd;
 911                 socknum++;
 912
 913                 if (maxfd < sockfd)
 914                         maxfd = sockfd;
 915         }
 916
 917         freeaddrinfo(ai0);
 918
 919         return socknum;
 920 }
 921
 922 #else /* NO_IPV6 */
 923
 924 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 925 {
 926         struct sockaddr_in sin;
 927         int sockfd;
 928         long flags;
 929
 930         memset(&sin, 0, sizeof sin);
 931         sin.sin_family = AF_INET;
 932         sin.sin_port = htons(listen_port);
 933
 934         if (listen_addr) {
 935                 /* Well, host better be an IP address here. */
 936                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 937                         return 0;
 938         } else {
 939                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 940         }
 941
 942         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 943         if (sockfd < 0)
 944                 return 0;
 945
 946         if (set_reuse_addr(sockfd)) {
 947                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 948                 close(sockfd);
 949                 return 0;
 950         }
 951
 952         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 953                 logerror("Could not listen to %s: %s",
 954                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 955                          strerror(errno));
 956                 close(sockfd);
 957                 return 0;
 958         }
 959
 960         if (listen(sockfd, 5) < 0) {
 961                 logerror("Could not listen to %s: %s",
 962                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 963                          strerror(errno));
 964                 close(sockfd);
 965                 return 0;
 966         }
 967
 968         flags = fcntl(sockfd, F_GETFD, 0);
 969         if (flags >= 0)
 970                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 971
 972         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 973         socklist->list[socklist->nr++] = sockfd;
 974         return 1;
 975 }
 976
 977 #endif
 978
 979 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 980 {
 981         if (!listen_addr->nr)
 982                 setup_named_sock(NULL, listen_port, socklist);
 983         else {
 984                 int i, socknum;
 985                 for (i = 0; i < listen_addr->nr; i++) {
 986                         socknum = setup_named_sock(listen_addr->items[i].string,
 987                                                    listen_port, socklist);
 988
 989                         if (socknum == 0)
 990                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 991                                          listen_addr->items[i].string, listen_port);
 992                 }
 993         }
 994 }
 995
 996 static int service_loop(struct socketlist *socklist)
 997 {
 998         struct pollfd *pfd;
 999         int i;
1000
1001         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1002
1003         for (i = 0; i < socklist->nr; i++) {
1004                 pfd[i].fd = socklist->list[i];
1005                 pfd[i].events = POLLIN;
1006         }
1007
1008         signal(SIGCHLD, child_handler);
1009
1010         for (;;) {
1011                 int i;
1012
1013                 check_dead_children();
1014
1015                 if (poll(pfd, socklist->nr, -1) < 0) {
1016                         if (errno != EINTR) {
1017                                 logerror("Poll failed, resuming: %s",
1018                                       strerror(errno));
1019                                 sleep(1);
1020                         }
1021                         continue;
1022                 }
1023
1024                 for (i = 0; i < socklist->nr; i++) {
1025                         if (pfd[i].revents & POLLIN) {
1026                                 union {
1027                                         struct sockaddr sa;
1028                                         struct sockaddr_in sai;
1029 #ifndef NO_IPV6
1030                                         struct sockaddr_in6 sai6;
1031 #endif
1032                                 } ss;
1033                                 socklen_t sslen = sizeof(ss);
1034                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1035                                 if (incoming < 0) {
1036                                         switch (errno) {
1037                                         case EAGAIN:
1038                                         case EINTR:
1039                                         case ECONNABORTED:
1040                                                 continue;
1041                                         default:
1042                                                 die_errno("accept returned");
1043                                         }
1044                                 }
1045                                 handle(incoming, &ss.sa, sslen);
1046                         }
1047                 }
1048         }
1049 }
1050
1051 #ifdef NO_POSIX_GOODIES
1052
1053 struct credentials;
1054
1055 static void drop_privileges(struct credentials *cred)
1056 {
1057         /* nothing */
1058 }
1059
1060 static void daemonize(void)
1061 {
1062         die("--detach not supported on this platform");
1063 }
1064
1065 static struct credentials *prepare_credentials(const char *user_name,
1066     const char *group_name)
1067 {
1068         die("--user not supported on this platform");
1069 }
1070
1071 #else
1072
1073 struct credentials {
1074         struct passwd *pass;
1075         gid_t gid;
1076 };
1077
1078 static void drop_privileges(struct credentials *cred)
1079 {
1080         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1081             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1082                 die("cannot drop privileges");
1083 }
1084
1085 static struct credentials *prepare_credentials(const char *user_name,
1086     const char *group_name)
1087 {
1088         static struct credentials c;
1089
1090         c.pass = getpwnam(user_name);
1091         if (!c.pass)
1092                 die("user not found - %s", user_name);
1093
1094         if (!group_name)
1095                 c.gid = c.pass->pw_gid;
1096         else {
1097                 struct group *group = getgrnam(group_name);
1098                 if (!group)
1099                         die("group not found - %s", group_name);
1100
1101                 c.gid = group->gr_gid;
1102         }
1103
1104         return &c;
1105 }
1106
1107 static void daemonize(void)
1108 {
1109         switch (fork()) {
1110                 case 0:
1111                         break;
1112                 case -1:
1113                         die_errno("fork failed");
1114                 default:
1115                         exit(0);
1116         }
1117         if (setsid() == -1)
1118                 die_errno("setsid failed");
1119         close(0);
1120         close(1);
1121         close(2);
1122         sanitize_stdfds();
1123 }
1124 #endif
1125
1126 static void store_pid(const char *path)
1127 {
1128         FILE *f = fopen(path, "w");
1129         if (!f)
1130                 die_errno("cannot open pid file '%s'", path);
1131         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1132                 die_errno("failed to write pid file '%s'", path);
1133 }
1134
1135 static int serve(struct string_list *listen_addr, int listen_port,
1136     struct credentials *cred)
1137 {
1138         struct socketlist socklist = { NULL, 0, 0 };
1139
1140         socksetup(listen_addr, listen_port, &socklist);
1141         if (socklist.nr == 0)
1142                 die("unable to allocate any listen sockets on port %u",
1143                     listen_port);
1144
1145         drop_privileges(cred);
1146
1147         loginfo("Ready to rumble");
1148
1149         return service_loop(&socklist);
1150 }
1151
1152 int main(int argc, char **argv)
1153 {
1154         int listen_port = 0;
1155         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1156         int serve_mode = 0, inetd_mode = 0;
1157         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1158         int detach = 0;
1159         struct credentials *cred = NULL;
1160         int i;
1161
1162         git_setup_gettext();
1163
1164         git_extract_argv0_path(argv[0]);
1165
1166         for (i = 1; i < argc; i++) {
1167                 char *arg = argv[i];
1168
1169                 if (!prefixcmp(arg, "--listen=")) {
1170                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1171                         continue;
1172                 }
1173                 if (!prefixcmp(arg, "--port=")) {
1174                         char *end;
1175                         unsigned long n;
1176                         n = strtoul(arg+7, &end, 0);
1177                         if (arg[7] && !*end) {
1178                                 listen_port = n;
1179                                 continue;
1180                         }
1181                 }
1182                 if (!strcmp(arg, "--serve")) {
1183                         serve_mode = 1;
1184                         continue;
1185                 }
1186                 if (!strcmp(arg, "--inetd")) {
1187                         inetd_mode = 1;
1188                         log_syslog = 1;
1189                         continue;
1190                 }
1191                 if (!strcmp(arg, "--verbose")) {
1192                         verbose = 1;
1193                         continue;
1194                 }
1195                 if (!strcmp(arg, "--syslog")) {
1196                         log_syslog = 1;
1197                         continue;
1198                 }
1199                 if (!strcmp(arg, "--export-all")) {
1200                         export_all_trees = 1;
1201                         continue;
1202                 }
1203                 if (!prefixcmp(arg, "--access-hook=")) {
1204                         access_hook = arg + 14;
1205                         continue;
1206                 }
1207                 if (!prefixcmp(arg, "--timeout=")) {
1208                         timeout = atoi(arg+10);
1209                         continue;
1210                 }
1211                 if (!prefixcmp(arg, "--init-timeout=")) {
1212                         init_timeout = atoi(arg+15);
1213                         continue;
1214                 }
1215                 if (!prefixcmp(arg, "--max-connections=")) {
1216                         max_connections = atoi(arg+18);
1217                         if (max_connections < 0)
1218                                 max_connections = 0;            /* unlimited */
1219                         continue;
1220                 }
1221                 if (!strcmp(arg, "--strict-paths")) {
1222                         strict_paths = 1;
1223                         continue;
1224                 }
1225                 if (!prefixcmp(arg, "--base-path=")) {
1226                         base_path = arg+12;
1227                         continue;
1228                 }
1229                 if (!strcmp(arg, "--base-path-relaxed")) {
1230                         base_path_relaxed = 1;
1231                         continue;
1232                 }
1233                 if (!prefixcmp(arg, "--interpolated-path=")) {
1234                         interpolated_path = arg+20;
1235                         continue;
1236                 }
1237                 if (!strcmp(arg, "--reuseaddr")) {
1238                         reuseaddr = 1;
1239                         continue;
1240                 }
1241                 if (!strcmp(arg, "--user-path")) {
1242                         user_path = "";
1243                         continue;
1244                 }
1245                 if (!prefixcmp(arg, "--user-path=")) {
1246                         user_path = arg + 12;
1247                         continue;
1248                 }
1249                 if (!prefixcmp(arg, "--pid-file=")) {
1250                         pid_file = arg + 11;
1251                         continue;
1252                 }
1253                 if (!strcmp(arg, "--detach")) {
1254                         detach = 1;
1255                         log_syslog = 1;
1256                         continue;
1257                 }
1258                 if (!prefixcmp(arg, "--user=")) {
1259                         user_name = arg + 7;
1260                         continue;
1261                 }
1262                 if (!prefixcmp(arg, "--group=")) {
1263                         group_name = arg + 8;
1264                         continue;
1265                 }
1266                 if (!prefixcmp(arg, "--enable=")) {
1267                         enable_service(arg + 9, 1);
1268                         continue;
1269                 }
1270                 if (!prefixcmp(arg, "--disable=")) {
1271                         enable_service(arg + 10, 0);
1272                         continue;
1273                 }
1274                 if (!prefixcmp(arg, "--allow-override=")) {
1275                         make_service_overridable(arg + 17, 1);
1276                         continue;
1277                 }
1278                 if (!prefixcmp(arg, "--forbid-override=")) {
1279                         make_service_overridable(arg + 18, 0);
1280                         continue;
1281                 }
1282                 if (!strcmp(arg, "--informative-errors")) {
1283                         informative_errors = 1;
1284                         continue;
1285                 }
1286                 if (!strcmp(arg, "--no-informative-errors")) {
1287                         informative_errors = 0;
1288                         continue;
1289                 }
1290                 if (!strcmp(arg, "--")) {
1291                         ok_paths = &argv[i+1];
1292                         break;
1293                 } else if (arg[0] != '-') {
1294                         ok_paths = &argv[i];
1295                         break;
1296                 }
1297
1298                 usage(daemon_usage);
1299         }
1300
1301         if (log_syslog) {
1302                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1303                 set_die_routine(daemon_die);
1304         } else
1305                 /* avoid splitting a message in the middle */
1306                 setvbuf(stderr, NULL, _IOFBF, 4096);
1307
1308         if (inetd_mode && (detach || group_name || user_name))
1309                 die("--detach, --user and --group are incompatible with --inetd");
1310
1311         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1312                 die("--listen= and --port= are incompatible with --inetd");
1313         else if (listen_port == 0)
1314                 listen_port = DEFAULT_GIT_PORT;
1315
1316         if (group_name && !user_name)
1317                 die("--group supplied without --user");
1318
1319         if (user_name)
1320                 cred = prepare_credentials(user_name, group_name);
1321
1322         if (strict_paths && (!ok_paths || !*ok_paths))
1323                 die("option --strict-paths requires a whitelist");
1324
1325         if (base_path && !is_directory(base_path))
1326                 die("base-path '%s' does not exist or is not a directory",
1327                     base_path);
1328
1329         if (inetd_mode) {
1330                 if (!freopen("/dev/null", "w", stderr))
1331                         die_errno("failed to redirect stderr to /dev/null");
1332         }
1333
1334         if (inetd_mode || serve_mode)
1335                 return execute();
1336
1337         if (detach)
1338                 daemonize();
1339         else
1340                 sanitize_stdfds();
1341
1342         if (pid_file)
1343                 store_pid(pid_file);
1344
1345         /* prepare argv for serving-processes */
1346         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1347         cld_argv[0] = argv[0];  /* git-daemon */
1348         cld_argv[1] = "--serve";
1349         for (i = 1; i < argc; ++i)
1350                 cld_argv[i+1] = argv[i];
1351         cld_argv[argc+1] = NULL;
1352
1353         return serve(&listen_addr, listen_port, cred);
1354 }