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 static int log_syslog;
  17 static int verbose;
  18 static int reuseaddr;
  19
  20 static const char daemon_usage[] =
  21 "git daemon [--verbose] [--syslog] [--export-all]\n"
  22 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  23 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  24 "           [--user-path | --user-path=<path>]\n"
  25 "           [--interpolated-path=<path>]\n"
  26 "           [--reuseaddr] [--detach] [--pid-file=<file>]\n"
  27 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  28 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  29 "                      [--user=<user> [--group=<group>]]\n"
  30 "           [<directory>...]";
  31
  32 /* List of acceptable pathname prefixes */
  33 static char **ok_paths;
  34 static int strict_paths;
  35
  36 /* If this is set, git-daemon-export-ok is not required */
  37 static int export_all_trees;
  38
  39 /* Take all paths relative to this one if non-NULL */
  40 static char *base_path;
  41 static char *interpolated_path;
  42 static int base_path_relaxed;
  43
  44 /* Flag indicating client sent extra args. */
  45 static int saw_extended_args;
  46
  47 /* If defined, ~user notation is allowed and the string is inserted
  48  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  49  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  50  */
  51 static const char *user_path;
  52
  53 /* Timeout, and initial timeout */
  54 static unsigned int timeout;
  55 static unsigned int init_timeout;
  56
  57 static char *hostname;
  58 static char *canon_hostname;
  59 static char *ip_address;
  60 static char *tcp_port;
  61
  62 static void logreport(int priority, const char *err, va_list params)
  63 {
  64         if (log_syslog) {
  65                 char buf[1024];
  66                 vsnprintf(buf, sizeof(buf), err, params);
  67                 syslog(priority, "%s", buf);
  68         } else {
  69                 /*
  70                  * Since stderr is set to linebuffered mode, the
  71                  * logging of different processes will not overlap
  72                  */
  73                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  74                 vfprintf(stderr, err, params);
  75                 fputc('\n', stderr);
  76         }
  77 }
  78
  79 __attribute__((format (printf, 1, 2)))
  80 static void logerror(const char *err, ...)
  81 {
  82         va_list params;
  83         va_start(params, err);
  84         logreport(LOG_ERR, err, params);
  85         va_end(params);
  86 }
  87
  88 __attribute__((format (printf, 1, 2)))
  89 static void loginfo(const char *err, ...)
  90 {
  91         va_list params;
  92         if (!verbose)
  93                 return;
  94         va_start(params, err);
  95         logreport(LOG_INFO, err, params);
  96         va_end(params);
  97 }
  98
  99 static void NORETURN daemon_die(const char *err, va_list params)
 100 {
 101         logreport(LOG_ERR, err, params);
 102         exit(1);
 103 }
 104
 105 static char *path_ok(char *directory)
 106 {
 107         static char rpath[PATH_MAX];
 108         static char interp_path[PATH_MAX];
 109         char *path;
 110         char *dir;
 111
 112         dir = directory;
 113
 114         if (daemon_avoid_alias(dir)) {
 115                 logerror("'%s': aliased", dir);
 116                 return NULL;
 117         }
 118
 119         if (*dir == '~') {
 120                 if (!user_path) {
 121                         logerror("'%s': User-path not allowed", dir);
 122                         return NULL;
 123                 }
 124                 if (*user_path) {
 125                         /* Got either "~alice" or "~alice/foo";
 126                          * rewrite them to "~alice/%s" or
 127                          * "~alice/%s/foo".
 128                          */
 129                         int namlen, restlen = strlen(dir);
 130                         char *slash = strchr(dir, '/');
 131                         if (!slash)
 132                                 slash = dir + restlen;
 133                         namlen = slash - dir;
 134                         restlen -= namlen;
 135                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 136                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 137                                  namlen, dir, user_path, restlen, slash);
 138                         dir = rpath;
 139                 }
 140         }
 141         else if (interpolated_path && saw_extended_args) {
 142                 struct strbuf expanded_path = STRBUF_INIT;
 143                 struct strbuf_expand_dict_entry dict[6];
 144
 145                 dict[0].placeholder = "H"; dict[0].value = hostname;
 146                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 147                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
 148                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
 149                 dict[4].placeholder = "D"; dict[4].value = directory;
 150                 dict[5].placeholder = NULL; dict[5].value = NULL;
 151                 if (*dir != '/') {
 152                         /* Allow only absolute */
 153                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 154                         return NULL;
 155                 }
 156
 157                 strbuf_expand(&expanded_path, interpolated_path,
 158                                 strbuf_expand_dict_cb, &dict);
 159                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 160                 strbuf_release(&expanded_path);
 161                 loginfo("Interpolated dir '%s'", interp_path);
 162
 163                 dir = interp_path;
 164         }
 165         else if (base_path) {
 166                 if (*dir != '/') {
 167                         /* Allow only absolute */
 168                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 169                         return NULL;
 170                 }
 171                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 172                 dir = rpath;
 173         }
 174
 175         path = enter_repo(dir, strict_paths);
 176         if (!path && base_path && base_path_relaxed) {
 177                 /*
 178                  * if we fail and base_path_relaxed is enabled, try without
 179                  * prefixing the base path
 180                  */
 181                 dir = directory;
 182                 path = enter_repo(dir, strict_paths);
 183         }
 184
 185         if (!path) {
 186                 logerror("'%s' does not appear to be a git repository", dir);
 187                 return NULL;
 188         }
 189
 190         if ( ok_paths && *ok_paths ) {
 191                 char **pp;
 192                 int pathlen = strlen(path);
 193
 194                 /* The validation is done on the paths after enter_repo
 195                  * appends optional {.git,.git/.git} and friends, but
 196                  * it does not use getcwd().  So if your /pub is
 197                  * a symlink to /mnt/pub, you can whitelist /pub and
 198                  * do not have to say /mnt/pub.
 199                  * Do not say /pub/.
 200                  */
 201                 for ( pp = ok_paths ; *pp ; pp++ ) {
 202                         int len = strlen(*pp);
 203                         if (len <= pathlen &&
 204                             !memcmp(*pp, path, len) &&
 205                             (path[len] == '\0' ||
 206                              (!strict_paths && path[len] == '/')))
 207                                 return path;
 208                 }
 209         }
 210         else {
 211                 /* be backwards compatible */
 212                 if (!strict_paths)
 213                         return path;
 214         }
 215
 216         logerror("'%s': not in whitelist", path);
 217         return NULL;            /* Fallthrough. Deny by default */
 218 }
 219
 220 typedef int (*daemon_service_fn)(void);
 221 struct daemon_service {
 222         const char *name;
 223         const char *config_name;
 224         daemon_service_fn fn;
 225         int enabled;
 226         int overridable;
 227 };
 228
 229 static struct daemon_service *service_looking_at;
 230 static int service_enabled;
 231
 232 static int git_daemon_config(const char *var, const char *value, void *cb)
 233 {
 234         if (!prefixcmp(var, "daemon.") &&
 235             !strcmp(var + 7, service_looking_at->config_name)) {
 236                 service_enabled = git_config_bool(var, value);
 237                 return 0;
 238         }
 239
 240         /* we are not interested in parsing any other configuration here */
 241         return 0;
 242 }
 243
 244 static int run_service(char *dir, struct daemon_service *service)
 245 {
 246         const char *path;
 247         int enabled = service->enabled;
 248
 249         loginfo("Request %s for '%s'", service->name, dir);
 250
 251         if (!enabled && !service->overridable) {
 252                 logerror("'%s': service not enabled.", service->name);
 253                 errno = EACCES;
 254                 return -1;
 255         }
 256
 257         if (!(path = path_ok(dir)))
 258                 return -1;
 259
 260         /*
 261          * Security on the cheap.
 262          *
 263          * We want a readable HEAD, usable "objects" directory, and
 264          * a "git-daemon-export-ok" flag that says that the other side
 265          * is ok with us doing this.
 266          *
 267          * path_ok() uses enter_repo() and does whitelist checking.
 268          * We only need to make sure the repository is exported.
 269          */
 270
 271         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 272                 logerror("'%s': repository not exported.", path);
 273                 errno = EACCES;
 274                 return -1;
 275         }
 276
 277         if (service->overridable) {
 278                 service_looking_at = service;
 279                 service_enabled = -1;
 280                 git_config(git_daemon_config, NULL);
 281                 if (0 <= service_enabled)
 282                         enabled = service_enabled;
 283         }
 284         if (!enabled) {
 285                 logerror("'%s': service not enabled for '%s'",
 286                          service->name, path);
 287                 errno = EACCES;
 288                 return -1;
 289         }
 290
 291         /*
 292          * We'll ignore SIGTERM from now on, we have a
 293          * good client.
 294          */
 295         signal(SIGTERM, SIG_IGN);
 296
 297         return service->fn();
 298 }
 299
 300 static void copy_to_log(int fd)
 301 {
 302         struct strbuf line = STRBUF_INIT;
 303         FILE *fp;
 304
 305         fp = fdopen(fd, "r");
 306         if (fp == NULL) {
 307                 logerror("fdopen of error channel failed");
 308                 close(fd);
 309                 return;
 310         }
 311
 312         while (strbuf_getline(&line, fp, '\n') != EOF) {
 313                 logerror("%s", line.buf);
 314                 strbuf_setlen(&line, 0);
 315         }
 316
 317         strbuf_release(&line);
 318         fclose(fp);
 319 }
 320
 321 static int run_service_command(const char **argv)
 322 {
 323         struct child_process cld;
 324
 325         memset(&cld, 0, sizeof(cld));
 326         cld.argv = argv;
 327         cld.git_cmd = 1;
 328         cld.err = -1;
 329         if (start_command(&cld))
 330                 return -1;
 331
 332         close(0);
 333         close(1);
 334
 335         copy_to_log(cld.err);
 336
 337         return finish_command(&cld);
 338 }
 339
 340 static int upload_pack(void)
 341 {
 342         /* Timeout as string */
 343         char timeout_buf[64];
 344         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 345
 346         argv[2] = timeout_buf;
 347
 348         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 349         return run_service_command(argv);
 350 }
 351
 352 static int upload_archive(void)
 353 {
 354         static const char *argv[] = { "upload-archive", ".", NULL };
 355         return run_service_command(argv);
 356 }
 357
 358 static int receive_pack(void)
 359 {
 360         static const char *argv[] = { "receive-pack", ".", NULL };
 361         return run_service_command(argv);
 362 }
 363
 364 static struct daemon_service daemon_service[] = {
 365         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 366         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 367         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 368 };
 369
 370 static void enable_service(const char *name, int ena)
 371 {
 372         int i;
 373         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 374                 if (!strcmp(daemon_service[i].name, name)) {
 375                         daemon_service[i].enabled = ena;
 376                         return;
 377                 }
 378         }
 379         die("No such service %s", name);
 380 }
 381
 382 static void make_service_overridable(const char *name, int ena)
 383 {
 384         int i;
 385         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 386                 if (!strcmp(daemon_service[i].name, name)) {
 387                         daemon_service[i].overridable = ena;
 388                         return;
 389                 }
 390         }
 391         die("No such service %s", name);
 392 }
 393
 394 static char *xstrdup_tolower(const char *str)
 395 {
 396         char *p, *dup = xstrdup(str);
 397         for (p = dup; *p; p++)
 398                 *p = tolower(*p);
 399         return dup;
 400 }
 401
 402 static void parse_host_and_port(char *hostport, char **host,
 403         char **port)
 404 {
 405         if (*hostport == '[') {
 406                 char *end;
 407
 408                 end = strchr(hostport, ']');
 409                 if (!end)
 410                         die("Invalid request ('[' without ']')");
 411                 *end = '\0';
 412                 *host = hostport + 1;
 413                 if (!end[1])
 414                         *port = NULL;
 415                 else if (end[1] == ':')
 416                         *port = end + 2;
 417                 else
 418                         die("Garbage after end of host part");
 419         } else {
 420                 *host = hostport;
 421                 *port = strrchr(hostport, ':');
 422                 if (*port) {
 423                         **port = '\0';
 424                         ++*port;
 425                 }
 426         }
 427 }
 428
 429 /*
 430  * Read the host as supplied by the client connection.
 431  */
 432 static void parse_host_arg(char *extra_args, int buflen)
 433 {
 434         char *val;
 435         int vallen;
 436         char *end = extra_args + buflen;
 437
 438         if (extra_args < end && *extra_args) {
 439                 saw_extended_args = 1;
 440                 if (strncasecmp("host=", extra_args, 5) == 0) {
 441                         val = extra_args + 5;
 442                         vallen = strlen(val) + 1;
 443                         if (*val) {
 444                                 /* Split <host>:<port> at colon. */
 445                                 char *host;
 446                                 char *port;
 447                                 parse_host_and_port(val, &host, &port);
 448                                 if (port) {
 449                                         free(tcp_port);
 450                                         tcp_port = xstrdup(port);
 451                                 }
 452                                 free(hostname);
 453                                 hostname = xstrdup_tolower(host);
 454                         }
 455
 456                         /* On to the next one */
 457                         extra_args = val + vallen;
 458                 }
 459                 if (extra_args < end && *extra_args)
 460                         die("Invalid request");
 461         }
 462
 463         /*
 464          * Locate canonical hostname and its IP address.
 465          */
 466         if (hostname) {
 467 #ifndef NO_IPV6
 468                 struct addrinfo hints;
 469                 struct addrinfo *ai;
 470                 int gai;
 471                 static char addrbuf[HOST_NAME_MAX + 1];
 472
 473                 memset(&hints, 0, sizeof(hints));
 474                 hints.ai_flags = AI_CANONNAME;
 475
 476                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 477                 if (!gai) {
 478                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 479
 480                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 481                                   addrbuf, sizeof(addrbuf));
 482                         free(ip_address);
 483                         ip_address = xstrdup(addrbuf);
 484
 485                         free(canon_hostname);
 486                         canon_hostname = xstrdup(ai->ai_canonname ?
 487                                                  ai->ai_canonname : ip_address);
 488
 489                         freeaddrinfo(ai);
 490                 }
 491 #else
 492                 struct hostent *hent;
 493                 struct sockaddr_in sa;
 494                 char **ap;
 495                 static char addrbuf[HOST_NAME_MAX + 1];
 496
 497                 hent = gethostbyname(hostname);
 498
 499                 ap = hent->h_addr_list;
 500                 memset(&sa, 0, sizeof sa);
 501                 sa.sin_family = hent->h_addrtype;
 502                 sa.sin_port = htons(0);
 503                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 504
 505                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 506                           addrbuf, sizeof(addrbuf));
 507
 508                 free(canon_hostname);
 509                 canon_hostname = xstrdup(hent->h_name);
 510                 free(ip_address);
 511                 ip_address = xstrdup(addrbuf);
 512 #endif
 513         }
 514 }
 515
 516
 517 static int execute(struct sockaddr *addr)
 518 {
 519         static char line[1000];
 520         int pktlen, len, i;
 521
 522         if (addr) {
 523                 char addrbuf[256] = "";
 524                 int port = -1;
 525
 526                 if (addr->sa_family == AF_INET) {
 527                         struct sockaddr_in *sin_addr = (void *) addr;
 528                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 529                         port = ntohs(sin_addr->sin_port);
 530 #ifndef NO_IPV6
 531                 } else if (addr && addr->sa_family == AF_INET6) {
 532                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 533
 534                         char *buf = addrbuf;
 535                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 536                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 537                         strcat(buf, "]");
 538
 539                         port = ntohs(sin6_addr->sin6_port);
 540 #endif
 541                 }
 542                 loginfo("Connection from %s:%d", addrbuf, port);
 543                 setenv("REMOTE_ADDR", addrbuf, 1);
 544         }
 545         else {
 546                 unsetenv("REMOTE_ADDR");
 547         }
 548
 549         alarm(init_timeout ? init_timeout : timeout);
 550         pktlen = packet_read_line(0, line, sizeof(line));
 551         alarm(0);
 552
 553         len = strlen(line);
 554         if (pktlen != len)
 555                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 556                         (int) pktlen - len,
 557                         (int) pktlen - len, line + len + 1);
 558         if (len && line[len-1] == '\n') {
 559                 line[--len] = 0;
 560                 pktlen--;
 561         }
 562
 563         free(hostname);
 564         free(canon_hostname);
 565         free(ip_address);
 566         free(tcp_port);
 567         hostname = canon_hostname = ip_address = tcp_port = NULL;
 568
 569         if (len != pktlen)
 570                 parse_host_arg(line + len + 1, pktlen - len - 1);
 571
 572         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 573                 struct daemon_service *s = &(daemon_service[i]);
 574                 int namelen = strlen(s->name);
 575                 if (!prefixcmp(line, "git-") &&
 576                     !strncmp(s->name, line + 4, namelen) &&
 577                     line[namelen + 4] == ' ') {
 578                         /*
 579                          * Note: The directory here is probably context sensitive,
 580                          * and might depend on the actual service being performed.
 581                          */
 582                         return run_service(line + namelen + 5, s);
 583                 }
 584         }
 585
 586         logerror("Protocol error: '%s'", line);
 587         return -1;
 588 }
 589
 590 static int addrcmp(const struct sockaddr_storage *s1,
 591     const struct sockaddr_storage *s2)
 592 {
 593         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 594         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 595
 596         if (sa1->sa_family != sa2->sa_family)
 597                 return sa1->sa_family - sa2->sa_family;
 598         if (sa1->sa_family == AF_INET)
 599                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 600                     &((struct sockaddr_in *)s2)->sin_addr,
 601                     sizeof(struct in_addr));
 602 #ifndef NO_IPV6
 603         if (sa1->sa_family == AF_INET6)
 604                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 605                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 606                     sizeof(struct in6_addr));
 607 #endif
 608         return 0;
 609 }
 610
 611 static int max_connections = 32;
 612
 613 static unsigned int live_children;
 614
 615 static struct child {
 616         struct child *next;
 617         pid_t pid;
 618         struct sockaddr_storage address;
 619 } *firstborn;
 620
 621 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 622 {
 623         struct child *newborn, **cradle;
 624
 625         newborn = xcalloc(1, sizeof(*newborn));
 626         live_children++;
 627         newborn->pid = pid;
 628         memcpy(&newborn->address, addr, addrlen);
 629         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 630                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 631                         break;
 632         newborn->next = *cradle;
 633         *cradle = newborn;
 634 }
 635
 636 static void remove_child(pid_t pid)
 637 {
 638         struct child **cradle, *blanket;
 639
 640         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 641                 if (blanket->pid == pid) {
 642                         *cradle = blanket->next;
 643                         live_children--;
 644                         free(blanket);
 645                         break;
 646                 }
 647 }
 648
 649 /*
 650  * This gets called if the number of connections grows
 651  * past "max_connections".
 652  *
 653  * We kill the newest connection from a duplicate IP.
 654  */
 655 static void kill_some_child(void)
 656 {
 657         const struct child *blanket, *next;
 658
 659         if (!(blanket = firstborn))
 660                 return;
 661
 662         for (; (next = blanket->next); blanket = next)
 663                 if (!addrcmp(&blanket->address, &next->address)) {
 664                         kill(blanket->pid, SIGTERM);
 665                         break;
 666                 }
 667 }
 668
 669 static void check_dead_children(void)
 670 {
 671         int status;
 672         pid_t pid;
 673
 674         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 675                 const char *dead = "";
 676                 remove_child(pid);
 677                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 678                         dead = " (with error)";
 679                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 680         }
 681 }
 682
 683 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 684 {
 685         pid_t pid;
 686
 687         if (max_connections && live_children >= max_connections) {
 688                 kill_some_child();
 689                 sleep(1);  /* give it some time to die */
 690                 check_dead_children();
 691                 if (live_children >= max_connections) {
 692                         close(incoming);
 693                         logerror("Too many children, dropping connection");
 694                         return;
 695                 }
 696         }
 697
 698         if ((pid = fork())) {
 699                 close(incoming);
 700                 if (pid < 0) {
 701                         logerror("Couldn't fork %s", strerror(errno));
 702                         return;
 703                 }
 704
 705                 add_child(pid, addr, addrlen);
 706                 return;
 707         }
 708
 709         dup2(incoming, 0);
 710         dup2(incoming, 1);
 711         close(incoming);
 712
 713         exit(execute(addr));
 714 }
 715
 716 static void child_handler(int signo)
 717 {
 718         /*
 719          * Otherwise empty handler because systemcalls will get interrupted
 720          * upon signal receipt
 721          * SysV needs the handler to be rearmed
 722          */
 723         signal(SIGCHLD, child_handler);
 724 }
 725
 726 static int set_reuse_addr(int sockfd)
 727 {
 728         int on = 1;
 729
 730         if (!reuseaddr)
 731                 return 0;
 732         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 733                           &on, sizeof(on));
 734 }
 735
 736 struct socketlist {
 737         int *list;
 738         size_t nr;
 739         size_t alloc;
 740 };
 741
 742 #ifndef NO_IPV6
 743
 744 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 745 {
 746         int socknum = 0;
 747         int maxfd = -1;
 748         char pbuf[NI_MAXSERV];
 749         struct addrinfo hints, *ai0, *ai;
 750         int gai;
 751         long flags;
 752
 753         sprintf(pbuf, "%d", listen_port);
 754         memset(&hints, 0, sizeof(hints));
 755         hints.ai_family = AF_UNSPEC;
 756         hints.ai_socktype = SOCK_STREAM;
 757         hints.ai_protocol = IPPROTO_TCP;
 758         hints.ai_flags = AI_PASSIVE;
 759
 760         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 761         if (gai) {
 762                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 763                 return 0;
 764         }
 765
 766         for (ai = ai0; ai; ai = ai->ai_next) {
 767                 int sockfd;
 768
 769                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 770                 if (sockfd < 0)
 771                         continue;
 772                 if (sockfd >= FD_SETSIZE) {
 773                         logerror("Socket descriptor too large");
 774                         close(sockfd);
 775                         continue;
 776                 }
 777
 778 #ifdef IPV6_V6ONLY
 779                 if (ai->ai_family == AF_INET6) {
 780                         int on = 1;
 781                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 782                                    &on, sizeof(on));
 783                         /* Note: error is not fatal */
 784                 }
 785 #endif
 786
 787                 if (set_reuse_addr(sockfd)) {
 788                         close(sockfd);
 789                         continue;
 790                 }
 791
 792                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 793                         close(sockfd);
 794                         continue;       /* not fatal */
 795                 }
 796                 if (listen(sockfd, 5) < 0) {
 797                         close(sockfd);
 798                         continue;       /* not fatal */
 799                 }
 800
 801                 flags = fcntl(sockfd, F_GETFD, 0);
 802                 if (flags >= 0)
 803                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 804
 805                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 806                 socklist->list[socklist->nr++] = sockfd;
 807                 socknum++;
 808
 809                 if (maxfd < sockfd)
 810                         maxfd = sockfd;
 811         }
 812
 813         freeaddrinfo(ai0);
 814
 815         return socknum;
 816 }
 817
 818 #else /* NO_IPV6 */
 819
 820 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 821 {
 822         struct sockaddr_in sin;
 823         int sockfd;
 824         long flags;
 825
 826         memset(&sin, 0, sizeof sin);
 827         sin.sin_family = AF_INET;
 828         sin.sin_port = htons(listen_port);
 829
 830         if (listen_addr) {
 831                 /* Well, host better be an IP address here. */
 832                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 833                         return 0;
 834         } else {
 835                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 836         }
 837
 838         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 839         if (sockfd < 0)
 840                 return 0;
 841
 842         if (set_reuse_addr(sockfd)) {
 843                 close(sockfd);
 844                 return 0;
 845         }
 846
 847         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 848                 close(sockfd);
 849                 return 0;
 850         }
 851
 852         if (listen(sockfd, 5) < 0) {
 853                 close(sockfd);
 854                 return 0;
 855         }
 856
 857         flags = fcntl(sockfd, F_GETFD, 0);
 858         if (flags >= 0)
 859                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 860
 861         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 862         socklist->list[socklist->nr++] = sockfd;
 863         return 1;
 864 }
 865
 866 #endif
 867
 868 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 869 {
 870         if (!listen_addr->nr)
 871                 setup_named_sock(NULL, listen_port, socklist);
 872         else {
 873                 int i, socknum;
 874                 for (i = 0; i < listen_addr->nr; i++) {
 875                         socknum = setup_named_sock(listen_addr->items[i].string,
 876                                                    listen_port, socklist);
 877
 878                         if (socknum == 0)
 879                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 880                                          listen_addr->items[i].string, listen_port);
 881                 }
 882         }
 883 }
 884
 885 static int service_loop(struct socketlist *socklist)
 886 {
 887         struct pollfd *pfd;
 888         int i;
 889
 890         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 891
 892         for (i = 0; i < socklist->nr; i++) {
 893                 pfd[i].fd = socklist->list[i];
 894                 pfd[i].events = POLLIN;
 895         }
 896
 897         signal(SIGCHLD, child_handler);
 898
 899         for (;;) {
 900                 int i;
 901
 902                 check_dead_children();
 903
 904                 if (poll(pfd, socklist->nr, -1) < 0) {
 905                         if (errno != EINTR) {
 906                                 logerror("Poll failed, resuming: %s",
 907                                       strerror(errno));
 908                                 sleep(1);
 909                         }
 910                         continue;
 911                 }
 912
 913                 for (i = 0; i < socklist->nr; i++) {
 914                         if (pfd[i].revents & POLLIN) {
 915                                 struct sockaddr_storage ss;
 916                                 unsigned int sslen = sizeof(ss);
 917                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 918                                 if (incoming < 0) {
 919                                         switch (errno) {
 920                                         case EAGAIN:
 921                                         case EINTR:
 922                                         case ECONNABORTED:
 923                                                 continue;
 924                                         default:
 925                                                 die_errno("accept returned");
 926                                         }
 927                                 }
 928                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 929                         }
 930                 }
 931         }
 932 }
 933
 934 /* if any standard file descriptor is missing open it to /dev/null */
 935 static void sanitize_stdfds(void)
 936 {
 937         int fd = open("/dev/null", O_RDWR, 0);
 938         while (fd != -1 && fd < 2)
 939                 fd = dup(fd);
 940         if (fd == -1)
 941                 die_errno("open /dev/null or dup failed");
 942         if (fd > 2)
 943                 close(fd);
 944 }
 945
 946 static void daemonize(void)
 947 {
 948         switch (fork()) {
 949                 case 0:
 950                         break;
 951                 case -1:
 952                         die_errno("fork failed");
 953                 default:
 954                         exit(0);
 955         }
 956         if (setsid() == -1)
 957                 die_errno("setsid failed");
 958         close(0);
 959         close(1);
 960         close(2);
 961         sanitize_stdfds();
 962 }
 963
 964 static void store_pid(const char *path)
 965 {
 966         FILE *f = fopen(path, "w");
 967         if (!f)
 968                 die_errno("cannot open pid file '%s'", path);
 969         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 970                 die_errno("failed to write pid file '%s'", path);
 971 }
 972
 973 static int serve(struct string_list *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 974 {
 975         struct socketlist socklist = { NULL, 0, 0 };
 976
 977         socksetup(listen_addr, listen_port, &socklist);
 978         if (socklist.nr == 0)
 979                 die("unable to allocate any listen sockets on port %u",
 980                     listen_port);
 981
 982         if (pass && gid &&
 983             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 984              setuid(pass->pw_uid)))
 985                 die("cannot drop privileges");
 986
 987         return service_loop(&socklist);
 988 }
 989
 990 int main(int argc, char **argv)
 991 {
 992         int listen_port = 0;
 993         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
 994         int inetd_mode = 0;
 995         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 996         int detach = 0;
 997         struct passwd *pass = NULL;
 998         struct group *group;
 999         gid_t gid = 0;
1000         int i;
1001
1002         git_extract_argv0_path(argv[0]);
1003
1004         for (i = 1; i < argc; i++) {
1005                 char *arg = argv[i];
1006
1007                 if (!prefixcmp(arg, "--listen=")) {
1008                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1009                         continue;
1010                 }
1011                 if (!prefixcmp(arg, "--port=")) {
1012                         char *end;
1013                         unsigned long n;
1014                         n = strtoul(arg+7, &end, 0);
1015                         if (arg[7] && !*end) {
1016                                 listen_port = n;
1017                                 continue;
1018                         }
1019                 }
1020                 if (!strcmp(arg, "--inetd")) {
1021                         inetd_mode = 1;
1022                         log_syslog = 1;
1023                         continue;
1024                 }
1025                 if (!strcmp(arg, "--verbose")) {
1026                         verbose = 1;
1027                         continue;
1028                 }
1029                 if (!strcmp(arg, "--syslog")) {
1030                         log_syslog = 1;
1031                         continue;
1032                 }
1033                 if (!strcmp(arg, "--export-all")) {
1034                         export_all_trees = 1;
1035                         continue;
1036                 }
1037                 if (!prefixcmp(arg, "--timeout=")) {
1038                         timeout = atoi(arg+10);
1039                         continue;
1040                 }
1041                 if (!prefixcmp(arg, "--init-timeout=")) {
1042                         init_timeout = atoi(arg+15);
1043                         continue;
1044                 }
1045                 if (!prefixcmp(arg, "--max-connections=")) {
1046                         max_connections = atoi(arg+18);
1047                         if (max_connections < 0)
1048                                 max_connections = 0;            /* unlimited */
1049                         continue;
1050                 }
1051                 if (!strcmp(arg, "--strict-paths")) {
1052                         strict_paths = 1;
1053                         continue;
1054                 }
1055                 if (!prefixcmp(arg, "--base-path=")) {
1056                         base_path = arg+12;
1057                         continue;
1058                 }
1059                 if (!strcmp(arg, "--base-path-relaxed")) {
1060                         base_path_relaxed = 1;
1061                         continue;
1062                 }
1063                 if (!prefixcmp(arg, "--interpolated-path=")) {
1064                         interpolated_path = arg+20;
1065                         continue;
1066                 }
1067                 if (!strcmp(arg, "--reuseaddr")) {
1068                         reuseaddr = 1;
1069                         continue;
1070                 }
1071                 if (!strcmp(arg, "--user-path")) {
1072                         user_path = "";
1073                         continue;
1074                 }
1075                 if (!prefixcmp(arg, "--user-path=")) {
1076                         user_path = arg + 12;
1077                         continue;
1078                 }
1079                 if (!prefixcmp(arg, "--pid-file=")) {
1080                         pid_file = arg + 11;
1081                         continue;
1082                 }
1083                 if (!strcmp(arg, "--detach")) {
1084                         detach = 1;
1085                         log_syslog = 1;
1086                         continue;
1087                 }
1088                 if (!prefixcmp(arg, "--user=")) {
1089                         user_name = arg + 7;
1090                         continue;
1091                 }
1092                 if (!prefixcmp(arg, "--group=")) {
1093                         group_name = arg + 8;
1094                         continue;
1095                 }
1096                 if (!prefixcmp(arg, "--enable=")) {
1097                         enable_service(arg + 9, 1);
1098                         continue;
1099                 }
1100                 if (!prefixcmp(arg, "--disable=")) {
1101                         enable_service(arg + 10, 0);
1102                         continue;
1103                 }
1104                 if (!prefixcmp(arg, "--allow-override=")) {
1105                         make_service_overridable(arg + 17, 1);
1106                         continue;
1107                 }
1108                 if (!prefixcmp(arg, "--forbid-override=")) {
1109                         make_service_overridable(arg + 18, 0);
1110                         continue;
1111                 }
1112                 if (!strcmp(arg, "--")) {
1113                         ok_paths = &argv[i+1];
1114                         break;
1115                 } else if (arg[0] != '-') {
1116                         ok_paths = &argv[i];
1117                         break;
1118                 }
1119
1120                 usage(daemon_usage);
1121         }
1122
1123         if (log_syslog) {
1124                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1125                 set_die_routine(daemon_die);
1126         } else
1127                 /* avoid splitting a message in the middle */
1128                 setvbuf(stderr, NULL, _IOLBF, 0);
1129
1130         if (inetd_mode && (group_name || user_name))
1131                 die("--user and --group are incompatible with --inetd");
1132
1133         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1134                 die("--listen= and --port= are incompatible with --inetd");
1135         else if (listen_port == 0)
1136                 listen_port = DEFAULT_GIT_PORT;
1137
1138         if (group_name && !user_name)
1139                 die("--group supplied without --user");
1140
1141         if (user_name) {
1142                 pass = getpwnam(user_name);
1143                 if (!pass)
1144                         die("user not found - %s", user_name);
1145
1146                 if (!group_name)
1147                         gid = pass->pw_gid;
1148                 else {
1149                         group = getgrnam(group_name);
1150                         if (!group)
1151                                 die("group not found - %s", group_name);
1152
1153                         gid = group->gr_gid;
1154                 }
1155         }
1156
1157         if (strict_paths && (!ok_paths || !*ok_paths))
1158                 die("option --strict-paths requires a whitelist");
1159
1160         if (base_path && !is_directory(base_path))
1161                 die("base-path '%s' does not exist or is not a directory",
1162                     base_path);
1163
1164         if (inetd_mode) {
1165                 struct sockaddr_storage ss;
1166                 struct sockaddr *peer = (struct sockaddr *)&ss;
1167                 socklen_t slen = sizeof(ss);
1168
1169                 if (!freopen("/dev/null", "w", stderr))
1170                         die_errno("failed to redirect stderr to /dev/null");
1171
1172                 if (getpeername(0, peer, &slen))
1173                         peer = NULL;
1174
1175                 return execute(peer);
1176         }
1177
1178         if (detach) {
1179                 daemonize();
1180                 loginfo("Ready to rumble");
1181         }
1182         else
1183                 sanitize_stdfds();
1184
1185         if (pid_file)
1186                 store_pid(pid_file);
1187
1188         return serve(&listen_addr, listen_port, pass, gid);
1189 }