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
 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 #endif
 597         }
 598 }
 599
 600
 601 static int execute(void)
 602 {
 603         char *line = packet_buffer;
 604         int pktlen, len, i;
 605         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 606
 607         if (addr)
 608                 loginfo("Connection from %s:%s", addr, port);
 609
 610         alarm(init_timeout ? init_timeout : timeout);
 611         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 612         alarm(0);
 613
 614         len = strlen(line);
 615         if (pktlen != len)
 616                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 617                         (int) pktlen - len,
 618                         (int) pktlen - len, line + len + 1);
 619         if (len && line[len-1] == '\n') {
 620                 line[--len] = 0;
 621                 pktlen--;
 622         }
 623
 624         free(hostname);
 625         free(canon_hostname);
 626         free(ip_address);
 627         free(tcp_port);
 628         hostname = canon_hostname = ip_address = tcp_port = NULL;
 629
 630         if (len != pktlen)
 631                 parse_host_arg(line + len + 1, pktlen - len - 1);
 632
 633         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 634                 struct daemon_service *s = &(daemon_service[i]);
 635                 int namelen = strlen(s->name);
 636                 if (!prefixcmp(line, "git-") &&
 637                     !strncmp(s->name, line + 4, namelen) &&
 638                     line[namelen + 4] == ' ') {
 639                         /*
 640                          * Note: The directory here is probably context sensitive,
 641                          * and might depend on the actual service being performed.
 642                          */
 643                         return run_service(line + namelen + 5, s);
 644                 }
 645         }
 646
 647         logerror("Protocol error: '%s'", line);
 648         return -1;
 649 }
 650
 651 static int addrcmp(const struct sockaddr_storage *s1,
 652     const struct sockaddr_storage *s2)
 653 {
 654         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 655         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 656
 657         if (sa1->sa_family != sa2->sa_family)
 658                 return sa1->sa_family - sa2->sa_family;
 659         if (sa1->sa_family == AF_INET)
 660                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 661                     &((struct sockaddr_in *)s2)->sin_addr,
 662                     sizeof(struct in_addr));
 663 #ifndef NO_IPV6
 664         if (sa1->sa_family == AF_INET6)
 665                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 666                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 667                     sizeof(struct in6_addr));
 668 #endif
 669         return 0;
 670 }
 671
 672 static int max_connections = 32;
 673
 674 static unsigned int live_children;
 675
 676 static struct child {
 677         struct child *next;
 678         struct child_process cld;
 679         struct sockaddr_storage address;
 680 } *firstborn;
 681
 682 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 683 {
 684         struct child *newborn, **cradle;
 685
 686         newborn = xcalloc(1, sizeof(*newborn));
 687         live_children++;
 688         memcpy(&newborn->cld, cld, sizeof(*cld));
 689         memcpy(&newborn->address, addr, addrlen);
 690         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 691                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 692                         break;
 693         newborn->next = *cradle;
 694         *cradle = newborn;
 695 }
 696
 697 /*
 698  * This gets called if the number of connections grows
 699  * past "max_connections".
 700  *
 701  * We kill the newest connection from a duplicate IP.
 702  */
 703 static void kill_some_child(void)
 704 {
 705         const struct child *blanket, *next;
 706
 707         if (!(blanket = firstborn))
 708                 return;
 709
 710         for (; (next = blanket->next); blanket = next)
 711                 if (!addrcmp(&blanket->address, &next->address)) {
 712                         kill(blanket->cld.pid, SIGTERM);
 713                         break;
 714                 }
 715 }
 716
 717 static void check_dead_children(void)
 718 {
 719         int status;
 720         pid_t pid;
 721
 722         struct child **cradle, *blanket;
 723         for (cradle = &firstborn; (blanket = *cradle);)
 724                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 725                         const char *dead = "";
 726                         if (status)
 727                                 dead = " (with error)";
 728                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 729
 730                         /* remove the child */
 731                         *cradle = blanket->next;
 732                         live_children--;
 733                         free(blanket);
 734                 } else
 735                         cradle = &blanket->next;
 736 }
 737
 738 static char **cld_argv;
 739 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 740 {
 741         struct child_process cld = { NULL };
 742         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 743         char *env[] = { addrbuf, portbuf, NULL };
 744
 745         if (max_connections && live_children >= max_connections) {
 746                 kill_some_child();
 747                 sleep(1);  /* give it some time to die */
 748                 check_dead_children();
 749                 if (live_children >= max_connections) {
 750                         close(incoming);
 751                         logerror("Too many children, dropping connection");
 752                         return;
 753                 }
 754         }
 755
 756         if (addr->sa_family == AF_INET) {
 757                 struct sockaddr_in *sin_addr = (void *) addr;
 758                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 759                     sizeof(addrbuf) - 12);
 760                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 761                     ntohs(sin_addr->sin_port));
 762 #ifndef NO_IPV6
 763         } else if (addr->sa_family == AF_INET6) {
 764                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 765
 766                 char *buf = addrbuf + 12;
 767                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 768                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 769                     sizeof(addrbuf) - 13);
 770                 strcat(buf, "]");
 771
 772                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 773                     ntohs(sin6_addr->sin6_port));
 774 #endif
 775         }
 776
 777         cld.env = (const char **)env;
 778         cld.argv = (const char **)cld_argv;
 779         cld.in = incoming;
 780         cld.out = dup(incoming);
 781
 782         if (start_command(&cld))
 783                 logerror("unable to fork");
 784         else
 785                 add_child(&cld, addr, addrlen);
 786         close(incoming);
 787 }
 788
 789 static void child_handler(int signo)
 790 {
 791         /*
 792          * Otherwise empty handler because systemcalls will get interrupted
 793          * upon signal receipt
 794          * SysV needs the handler to be rearmed
 795          */
 796         signal(SIGCHLD, child_handler);
 797 }
 798
 799 static int set_reuse_addr(int sockfd)
 800 {
 801         int on = 1;
 802
 803         if (!reuseaddr)
 804                 return 0;
 805         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 806                           &on, sizeof(on));
 807 }
 808
 809 struct socketlist {
 810         int *list;
 811         size_t nr;
 812         size_t alloc;
 813 };
 814
 815 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 816 {
 817 #ifdef NO_IPV6
 818         static char ip[INET_ADDRSTRLEN];
 819 #else
 820         static char ip[INET6_ADDRSTRLEN];
 821 #endif
 822
 823         switch (family) {
 824 #ifndef NO_IPV6
 825         case AF_INET6:
 826                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 827                 break;
 828 #endif
 829         case AF_INET:
 830                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 831                 break;
 832         default:
 833                 strcpy(ip, "<unknown>");
 834         }
 835         return ip;
 836 }
 837
 838 #ifndef NO_IPV6
 839
 840 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 841 {
 842         int socknum = 0;
 843         int maxfd = -1;
 844         char pbuf[NI_MAXSERV];
 845         struct addrinfo hints, *ai0, *ai;
 846         int gai;
 847         long flags;
 848
 849         sprintf(pbuf, "%d", listen_port);
 850         memset(&hints, 0, sizeof(hints));
 851         hints.ai_family = AF_UNSPEC;
 852         hints.ai_socktype = SOCK_STREAM;
 853         hints.ai_protocol = IPPROTO_TCP;
 854         hints.ai_flags = AI_PASSIVE;
 855
 856         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 857         if (gai) {
 858                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 859                 return 0;
 860         }
 861
 862         for (ai = ai0; ai; ai = ai->ai_next) {
 863                 int sockfd;
 864
 865                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 866                 if (sockfd < 0)
 867                         continue;
 868                 if (sockfd >= FD_SETSIZE) {
 869                         logerror("Socket descriptor too large");
 870                         close(sockfd);
 871                         continue;
 872                 }
 873
 874 #ifdef IPV6_V6ONLY
 875                 if (ai->ai_family == AF_INET6) {
 876                         int on = 1;
 877                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 878                                    &on, sizeof(on));
 879                         /* Note: error is not fatal */
 880                 }
 881 #endif
 882
 883                 if (set_reuse_addr(sockfd)) {
 884                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 885                         close(sockfd);
 886                         continue;
 887                 }
 888
 889                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 890                         logerror("Could not bind to %s: %s",
 891                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 892                                  strerror(errno));
 893                         close(sockfd);
 894                         continue;       /* not fatal */
 895                 }
 896                 if (listen(sockfd, 5) < 0) {
 897                         logerror("Could not listen to %s: %s",
 898                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 899                                  strerror(errno));
 900                         close(sockfd);
 901                         continue;       /* not fatal */
 902                 }
 903
 904                 flags = fcntl(sockfd, F_GETFD, 0);
 905                 if (flags >= 0)
 906                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 907
 908                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 909                 socklist->list[socklist->nr++] = sockfd;
 910                 socknum++;
 911
 912                 if (maxfd < sockfd)
 913                         maxfd = sockfd;
 914         }
 915
 916         freeaddrinfo(ai0);
 917
 918         return socknum;
 919 }
 920
 921 #else /* NO_IPV6 */
 922
 923 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 924 {
 925         struct sockaddr_in sin;
 926         int sockfd;
 927         long flags;
 928
 929         memset(&sin, 0, sizeof sin);
 930         sin.sin_family = AF_INET;
 931         sin.sin_port = htons(listen_port);
 932
 933         if (listen_addr) {
 934                 /* Well, host better be an IP address here. */
 935                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 936                         return 0;
 937         } else {
 938                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 939         }
 940
 941         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 942         if (sockfd < 0)
 943                 return 0;
 944
 945         if (set_reuse_addr(sockfd)) {
 946                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 947                 close(sockfd);
 948                 return 0;
 949         }
 950
 951         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 952                 logerror("Could not listen to %s: %s",
 953                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 954                          strerror(errno));
 955                 close(sockfd);
 956                 return 0;
 957         }
 958
 959         if (listen(sockfd, 5) < 0) {
 960                 logerror("Could not listen to %s: %s",
 961                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 962                          strerror(errno));
 963                 close(sockfd);
 964                 return 0;
 965         }
 966
 967         flags = fcntl(sockfd, F_GETFD, 0);
 968         if (flags >= 0)
 969                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 970
 971         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 972         socklist->list[socklist->nr++] = sockfd;
 973         return 1;
 974 }
 975
 976 #endif
 977
 978 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 979 {
 980         if (!listen_addr->nr)
 981                 setup_named_sock(NULL, listen_port, socklist);
 982         else {
 983                 int i, socknum;
 984                 for (i = 0; i < listen_addr->nr; i++) {
 985                         socknum = setup_named_sock(listen_addr->items[i].string,
 986                                                    listen_port, socklist);
 987
 988                         if (socknum == 0)
 989                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 990                                          listen_addr->items[i].string, listen_port);
 991                 }
 992         }
 993 }
 994
 995 static int service_loop(struct socketlist *socklist)
 996 {
 997         struct pollfd *pfd;
 998         int i;
 999
1000         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1001
1002         for (i = 0; i < socklist->nr; i++) {
1003                 pfd[i].fd = socklist->list[i];
1004                 pfd[i].events = POLLIN;
1005         }
1006
1007         signal(SIGCHLD, child_handler);
1008
1009         for (;;) {
1010                 int i;
1011
1012                 check_dead_children();
1013
1014                 if (poll(pfd, socklist->nr, -1) < 0) {
1015                         if (errno != EINTR) {
1016                                 logerror("Poll failed, resuming: %s",
1017                                       strerror(errno));
1018                                 sleep(1);
1019                         }
1020                         continue;
1021                 }
1022
1023                 for (i = 0; i < socklist->nr; i++) {
1024                         if (pfd[i].revents & POLLIN) {
1025                                 union {
1026                                         struct sockaddr sa;
1027                                         struct sockaddr_in sai;
1028 #ifndef NO_IPV6
1029                                         struct sockaddr_in6 sai6;
1030 #endif
1031                                 } ss;
1032                                 socklen_t sslen = sizeof(ss);
1033                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1034                                 if (incoming < 0) {
1035                                         switch (errno) {
1036                                         case EAGAIN:
1037                                         case EINTR:
1038                                         case ECONNABORTED:
1039                                                 continue;
1040                                         default:
1041                                                 die_errno("accept returned");
1042                                         }
1043                                 }
1044                                 handle(incoming, &ss.sa, sslen);
1045                         }
1046                 }
1047         }
1048 }
1049
1050 #ifdef NO_POSIX_GOODIES
1051
1052 struct credentials;
1053
1054 static void drop_privileges(struct credentials *cred)
1055 {
1056         /* nothing */
1057 }
1058
1059 static void daemonize(void)
1060 {
1061         die("--detach not supported on this platform");
1062 }
1063
1064 static struct credentials *prepare_credentials(const char *user_name,
1065     const char *group_name)
1066 {
1067         die("--user not supported on this platform");
1068 }
1069
1070 #else
1071
1072 struct credentials {
1073         struct passwd *pass;
1074         gid_t gid;
1075 };
1076
1077 static void drop_privileges(struct credentials *cred)
1078 {
1079         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1080             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1081                 die("cannot drop privileges");
1082 }
1083
1084 static struct credentials *prepare_credentials(const char *user_name,
1085     const char *group_name)
1086 {
1087         static struct credentials c;
1088
1089         c.pass = getpwnam(user_name);
1090         if (!c.pass)
1091                 die("user not found - %s", user_name);
1092
1093         if (!group_name)
1094                 c.gid = c.pass->pw_gid;
1095         else {
1096                 struct group *group = getgrnam(group_name);
1097                 if (!group)
1098                         die("group not found - %s", group_name);
1099
1100                 c.gid = group->gr_gid;
1101         }
1102
1103         return &c;
1104 }
1105
1106 static void daemonize(void)
1107 {
1108         switch (fork()) {
1109                 case 0:
1110                         break;
1111                 case -1:
1112                         die_errno("fork failed");
1113                 default:
1114                         exit(0);
1115         }
1116         if (setsid() == -1)
1117                 die_errno("setsid failed");
1118         close(0);
1119         close(1);
1120         close(2);
1121         sanitize_stdfds();
1122 }
1123 #endif
1124
1125 static void store_pid(const char *path)
1126 {
1127         FILE *f = fopen(path, "w");
1128         if (!f)
1129                 die_errno("cannot open pid file '%s'", path);
1130         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1131                 die_errno("failed to write pid file '%s'", path);
1132 }
1133
1134 static int serve(struct string_list *listen_addr, int listen_port,
1135     struct credentials *cred)
1136 {
1137         struct socketlist socklist = { NULL, 0, 0 };
1138
1139         socksetup(listen_addr, listen_port, &socklist);
1140         if (socklist.nr == 0)
1141                 die("unable to allocate any listen sockets on port %u",
1142                     listen_port);
1143
1144         drop_privileges(cred);
1145
1146         loginfo("Ready to rumble");
1147
1148         return service_loop(&socklist);
1149 }
1150
1151 int main(int argc, char **argv)
1152 {
1153         int listen_port = 0;
1154         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1155         int serve_mode = 0, inetd_mode = 0;
1156         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1157         int detach = 0;
1158         struct credentials *cred = NULL;
1159         int i;
1160
1161         git_setup_gettext();
1162
1163         git_extract_argv0_path(argv[0]);
1164
1165         for (i = 1; i < argc; i++) {
1166                 char *arg = argv[i];
1167
1168                 if (!prefixcmp(arg, "--listen=")) {
1169                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1170                         continue;
1171                 }
1172                 if (!prefixcmp(arg, "--port=")) {
1173                         char *end;
1174                         unsigned long n;
1175                         n = strtoul(arg+7, &end, 0);
1176                         if (arg[7] && !*end) {
1177                                 listen_port = n;
1178                                 continue;
1179                         }
1180                 }
1181                 if (!strcmp(arg, "--serve")) {
1182                         serve_mode = 1;
1183                         continue;
1184                 }
1185                 if (!strcmp(arg, "--inetd")) {
1186                         inetd_mode = 1;
1187                         log_syslog = 1;
1188                         continue;
1189                 }
1190                 if (!strcmp(arg, "--verbose")) {
1191                         verbose = 1;
1192                         continue;
1193                 }
1194                 if (!strcmp(arg, "--syslog")) {
1195                         log_syslog = 1;
1196                         continue;
1197                 }
1198                 if (!strcmp(arg, "--export-all")) {
1199                         export_all_trees = 1;
1200                         continue;
1201                 }
1202                 if (!prefixcmp(arg, "--access-hook=")) {
1203                         access_hook = arg + 14;
1204                         continue;
1205                 }
1206                 if (!prefixcmp(arg, "--timeout=")) {
1207                         timeout = atoi(arg+10);
1208                         continue;
1209                 }
1210                 if (!prefixcmp(arg, "--init-timeout=")) {
1211                         init_timeout = atoi(arg+15);
1212                         continue;
1213                 }
1214                 if (!prefixcmp(arg, "--max-connections=")) {
1215                         max_connections = atoi(arg+18);
1216                         if (max_connections < 0)
1217                                 max_connections = 0;            /* unlimited */
1218                         continue;
1219                 }
1220                 if (!strcmp(arg, "--strict-paths")) {
1221                         strict_paths = 1;
1222                         continue;
1223                 }
1224                 if (!prefixcmp(arg, "--base-path=")) {
1225                         base_path = arg+12;
1226                         continue;
1227                 }
1228                 if (!strcmp(arg, "--base-path-relaxed")) {
1229                         base_path_relaxed = 1;
1230                         continue;
1231                 }
1232                 if (!prefixcmp(arg, "--interpolated-path=")) {
1233                         interpolated_path = arg+20;
1234                         continue;
1235                 }
1236                 if (!strcmp(arg, "--reuseaddr")) {
1237                         reuseaddr = 1;
1238                         continue;
1239                 }
1240                 if (!strcmp(arg, "--user-path")) {
1241                         user_path = "";
1242                         continue;
1243                 }
1244                 if (!prefixcmp(arg, "--user-path=")) {
1245                         user_path = arg + 12;
1246                         continue;
1247                 }
1248                 if (!prefixcmp(arg, "--pid-file=")) {
1249                         pid_file = arg + 11;
1250                         continue;
1251                 }
1252                 if (!strcmp(arg, "--detach")) {
1253                         detach = 1;
1254                         log_syslog = 1;
1255                         continue;
1256                 }
1257                 if (!prefixcmp(arg, "--user=")) {
1258                         user_name = arg + 7;
1259                         continue;
1260                 }
1261                 if (!prefixcmp(arg, "--group=")) {
1262                         group_name = arg + 8;
1263                         continue;
1264                 }
1265                 if (!prefixcmp(arg, "--enable=")) {
1266                         enable_service(arg + 9, 1);
1267                         continue;
1268                 }
1269                 if (!prefixcmp(arg, "--disable=")) {
1270                         enable_service(arg + 10, 0);
1271                         continue;
1272                 }
1273                 if (!prefixcmp(arg, "--allow-override=")) {
1274                         make_service_overridable(arg + 17, 1);
1275                         continue;
1276                 }
1277                 if (!prefixcmp(arg, "--forbid-override=")) {
1278                         make_service_overridable(arg + 18, 0);
1279                         continue;
1280                 }
1281                 if (!prefixcmp(arg, "--informative-errors")) {
1282                         informative_errors = 1;
1283                         continue;
1284                 }
1285                 if (!prefixcmp(arg, "--no-informative-errors")) {
1286                         informative_errors = 0;
1287                         continue;
1288                 }
1289                 if (!strcmp(arg, "--")) {
1290                         ok_paths = &argv[i+1];
1291                         break;
1292                 } else if (arg[0] != '-') {
1293                         ok_paths = &argv[i];
1294                         break;
1295                 }
1296
1297                 usage(daemon_usage);
1298         }
1299
1300         if (log_syslog) {
1301                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1302                 set_die_routine(daemon_die);
1303         } else
1304                 /* avoid splitting a message in the middle */
1305                 setvbuf(stderr, NULL, _IOFBF, 4096);
1306
1307         if (inetd_mode && (detach || group_name || user_name))
1308                 die("--detach, --user and --group are incompatible with --inetd");
1309
1310         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1311                 die("--listen= and --port= are incompatible with --inetd");
1312         else if (listen_port == 0)
1313                 listen_port = DEFAULT_GIT_PORT;
1314
1315         if (group_name && !user_name)
1316                 die("--group supplied without --user");
1317
1318         if (user_name)
1319                 cred = prepare_credentials(user_name, group_name);
1320
1321         if (strict_paths && (!ok_paths || !*ok_paths))
1322                 die("option --strict-paths requires a whitelist");
1323
1324         if (base_path && !is_directory(base_path))
1325                 die("base-path '%s' does not exist or is not a directory",
1326                     base_path);
1327
1328         if (inetd_mode) {
1329                 if (!freopen("/dev/null", "w", stderr))
1330                         die_errno("failed to redirect stderr to /dev/null");
1331         }
1332
1333         if (inetd_mode || serve_mode)
1334                 return execute();
1335
1336         if (detach)
1337                 daemonize();
1338         else
1339                 sanitize_stdfds();
1340
1341         if (pid_file)
1342                 store_pid(pid_file);
1343
1344         /* prepare argv for serving-processes */
1345         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1346         cld_argv[0] = argv[0];  /* git-daemon */
1347         cld_argv[1] = "--serve";
1348         for (i = 1; i < argc; ++i)
1349                 cld_argv[i+1] = argv[i];
1350         cld_argv[argc+1] = NULL;
1351
1352         return serve(&listen_addr, listen_port, cred);
1353 }