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