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