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
   7 #include <syslog.h>
   8
   9 #ifndef HOST_NAME_MAX
  10 #define HOST_NAME_MAX 256
  11 #endif
  12
  13 #ifndef NI_MAXSERV
  14 #define NI_MAXSERV 32
  15 #endif
  16
  17 static int log_syslog;
  18 static int verbose;
  19 static int reuseaddr;
  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] [--detach] [--pid-file=file]\n"
  28 "           [--[enable|disable|allow-override|forbid-override]=service]\n"
  29 "           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
  30 "                      [--user=user [--group=group]]\n"
  31 "           [directory...]";
  32
  33 /* List of acceptable pathname prefixes */
  34 static char **ok_paths;
  35 static int strict_paths;
  36
  37 /* If this is set, git-daemon-export-ok is not required */
  38 static int export_all_trees;
  39
  40 /* Take all paths relative to this one if non-NULL */
  41 static char *base_path;
  42 static char *interpolated_path;
  43 static int base_path_relaxed;
  44
  45 /* Flag indicating client sent extra args. */
  46 static int saw_extended_args;
  47
  48 /* If defined, ~user notation is allowed and the string is inserted
  49  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  50  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  51  */
  52 static const char *user_path;
  53
  54 /* Timeout, and initial timeout */
  55 static unsigned int timeout;
  56 static unsigned int init_timeout;
  57
  58 static char *hostname;
  59 static char *canon_hostname;
  60 static char *ip_address;
  61 static char *tcp_port;
  62
  63 static void logreport(int priority, const char *err, va_list params)
  64 {
  65         if (log_syslog) {
  66                 char buf[1024];
  67                 vsnprintf(buf, sizeof(buf), err, params);
  68                 syslog(priority, "%s", buf);
  69         } else {
  70                 /*
  71                  * Since stderr is set to linebuffered mode, the
  72                  * logging of different processes will not overlap
  73                  */
  74                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  75                 vfprintf(stderr, err, params);
  76                 fputc('\n', stderr);
  77         }
  78 }
  79
  80 __attribute__((format (printf, 1, 2)))
  81 static void logerror(const char *err, ...)
  82 {
  83         va_list params;
  84         va_start(params, err);
  85         logreport(LOG_ERR, err, params);
  86         va_end(params);
  87 }
  88
  89 __attribute__((format (printf, 1, 2)))
  90 static void loginfo(const char *err, ...)
  91 {
  92         va_list params;
  93         if (!verbose)
  94                 return;
  95         va_start(params, err);
  96         logreport(LOG_INFO, err, params);
  97         va_end(params);
  98 }
  99
 100 static void NORETURN daemon_die(const char *err, va_list params)
 101 {
 102         logreport(LOG_ERR, err, params);
 103         exit(1);
 104 }
 105
 106 static char *path_ok(char *directory)
 107 {
 108         static char rpath[PATH_MAX];
 109         static char interp_path[PATH_MAX];
 110         char *path;
 111         char *dir;
 112
 113         dir = directory;
 114
 115         if (daemon_avoid_alias(dir)) {
 116                 logerror("'%s': aliased", dir);
 117                 return NULL;
 118         }
 119
 120         if (*dir == '~') {
 121                 if (!user_path) {
 122                         logerror("'%s': User-path not allowed", dir);
 123                         return NULL;
 124                 }
 125                 if (*user_path) {
 126                         /* Got either "~alice" or "~alice/foo";
 127                          * rewrite them to "~alice/%s" or
 128                          * "~alice/%s/foo".
 129                          */
 130                         int namlen, restlen = strlen(dir);
 131                         char *slash = strchr(dir, '/');
 132                         if (!slash)
 133                                 slash = dir + restlen;
 134                         namlen = slash - dir;
 135                         restlen -= namlen;
 136                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 137                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 138                                  namlen, dir, user_path, restlen, slash);
 139                         dir = rpath;
 140                 }
 141         }
 142         else if (interpolated_path && saw_extended_args) {
 143                 struct strbuf expanded_path = STRBUF_INIT;
 144                 struct strbuf_expand_dict_entry dict[6];
 145
 146                 dict[0].placeholder = "H"; dict[0].value = hostname;
 147                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 148                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
 149                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
 150                 dict[4].placeholder = "D"; dict[4].value = directory;
 151                 dict[5].placeholder = NULL; dict[5].value = NULL;
 152                 if (*dir != '/') {
 153                         /* Allow only absolute */
 154                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 155                         return NULL;
 156                 }
 157
 158                 strbuf_expand(&expanded_path, interpolated_path,
 159                                 strbuf_expand_dict_cb, &dict);
 160                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 161                 strbuf_release(&expanded_path);
 162                 loginfo("Interpolated dir '%s'", interp_path);
 163
 164                 dir = interp_path;
 165         }
 166         else if (base_path) {
 167                 if (*dir != '/') {
 168                         /* Allow only absolute */
 169                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 170                         return NULL;
 171                 }
 172                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 173                 dir = rpath;
 174         }
 175
 176         path = enter_repo(dir, strict_paths);
 177         if (!path && base_path && base_path_relaxed) {
 178                 /*
 179                  * if we fail and base_path_relaxed is enabled, try without
 180                  * prefixing the base path
 181                  */
 182                 dir = directory;
 183                 path = enter_repo(dir, strict_paths);
 184         }
 185
 186         if (!path) {
 187                 logerror("'%s' does not appear to be a git repository", dir);
 188                 return NULL;
 189         }
 190
 191         if ( ok_paths && *ok_paths ) {
 192                 char **pp;
 193                 int pathlen = strlen(path);
 194
 195                 /* The validation is done on the paths after enter_repo
 196                  * appends optional {.git,.git/.git} and friends, but
 197                  * it does not use getcwd().  So if your /pub is
 198                  * a symlink to /mnt/pub, you can whitelist /pub and
 199                  * do not have to say /mnt/pub.
 200                  * Do not say /pub/.
 201                  */
 202                 for ( pp = ok_paths ; *pp ; pp++ ) {
 203                         int len = strlen(*pp);
 204                         if (len <= pathlen &&
 205                             !memcmp(*pp, path, len) &&
 206                             (path[len] == '\0' ||
 207                              (!strict_paths && path[len] == '/')))
 208                                 return path;
 209                 }
 210         }
 211         else {
 212                 /* be backwards compatible */
 213                 if (!strict_paths)
 214                         return path;
 215         }
 216
 217         logerror("'%s': not in whitelist", path);
 218         return NULL;            /* Fallthrough. Deny by default */
 219 }
 220
 221 typedef int (*daemon_service_fn)(void);
 222 struct daemon_service {
 223         const char *name;
 224         const char *config_name;
 225         daemon_service_fn fn;
 226         int enabled;
 227         int overridable;
 228 };
 229
 230 static struct daemon_service *service_looking_at;
 231 static int service_enabled;
 232
 233 static int git_daemon_config(const char *var, const char *value, void *cb)
 234 {
 235         if (!prefixcmp(var, "daemon.") &&
 236             !strcmp(var + 7, service_looking_at->config_name)) {
 237                 service_enabled = git_config_bool(var, value);
 238                 return 0;
 239         }
 240
 241         /* we are not interested in parsing any other configuration here */
 242         return 0;
 243 }
 244
 245 static int run_service(char *dir, struct daemon_service *service)
 246 {
 247         const char *path;
 248         int enabled = service->enabled;
 249
 250         loginfo("Request %s for '%s'", service->name, dir);
 251
 252         if (!enabled && !service->overridable) {
 253                 logerror("'%s': service not enabled.", service->name);
 254                 errno = EACCES;
 255                 return -1;
 256         }
 257
 258         if (!(path = path_ok(dir)))
 259                 return -1;
 260
 261         /*
 262          * Security on the cheap.
 263          *
 264          * We want a readable HEAD, usable "objects" directory, and
 265          * a "git-daemon-export-ok" flag that says that the other side
 266          * is ok with us doing this.
 267          *
 268          * path_ok() uses enter_repo() and does whitelist checking.
 269          * We only need to make sure the repository is exported.
 270          */
 271
 272         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 273                 logerror("'%s': repository not exported.", path);
 274                 errno = EACCES;
 275                 return -1;
 276         }
 277
 278         if (service->overridable) {
 279                 service_looking_at = service;
 280                 service_enabled = -1;
 281                 git_config(git_daemon_config, NULL);
 282                 if (0 <= service_enabled)
 283                         enabled = service_enabled;
 284         }
 285         if (!enabled) {
 286                 logerror("'%s': service not enabled for '%s'",
 287                          service->name, path);
 288                 errno = EACCES;
 289                 return -1;
 290         }
 291
 292         /*
 293          * We'll ignore SIGTERM from now on, we have a
 294          * good client.
 295          */
 296         signal(SIGTERM, SIG_IGN);
 297
 298         return service->fn();
 299 }
 300
 301 static void copy_to_log(int fd)
 302 {
 303         struct strbuf line = STRBUF_INIT;
 304         FILE *fp;
 305
 306         fp = fdopen(fd, "r");
 307         if (fp == NULL) {
 308                 logerror("fdopen of error channel failed");
 309                 close(fd);
 310                 return;
 311         }
 312
 313         while (strbuf_getline(&line, fp, '\n') != EOF) {
 314                 logerror("%s", line.buf);
 315                 strbuf_setlen(&line, 0);
 316         }
 317
 318         strbuf_release(&line);
 319         fclose(fp);
 320 }
 321
 322 static int run_service_command(const char **argv)
 323 {
 324         struct child_process cld;
 325
 326         memset(&cld, 0, sizeof(cld));
 327         cld.argv = argv;
 328         cld.git_cmd = 1;
 329         cld.err = -1;
 330         if (start_command(&cld))
 331                 return -1;
 332
 333         close(0);
 334         close(1);
 335
 336         copy_to_log(cld.err);
 337
 338         return finish_command(&cld);
 339 }
 340
 341 static int upload_pack(void)
 342 {
 343         /* Timeout as string */
 344         char timeout_buf[64];
 345         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 346
 347         argv[2] = timeout_buf;
 348
 349         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 350         return run_service_command(argv);
 351 }
 352
 353 static int upload_archive(void)
 354 {
 355         static const char *argv[] = { "upload-archive", ".", NULL };
 356         return run_service_command(argv);
 357 }
 358
 359 static int receive_pack(void)
 360 {
 361         static const char *argv[] = { "receive-pack", ".", NULL };
 362         return run_service_command(argv);
 363 }
 364
 365 static struct daemon_service daemon_service[] = {
 366         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 367         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 368         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 369 };
 370
 371 static void enable_service(const char *name, int ena)
 372 {
 373         int i;
 374         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 375                 if (!strcmp(daemon_service[i].name, name)) {
 376                         daemon_service[i].enabled = ena;
 377                         return;
 378                 }
 379         }
 380         die("No such service %s", name);
 381 }
 382
 383 static void make_service_overridable(const char *name, int ena)
 384 {
 385         int i;
 386         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 387                 if (!strcmp(daemon_service[i].name, name)) {
 388                         daemon_service[i].overridable = ena;
 389                         return;
 390                 }
 391         }
 392         die("No such service %s", name);
 393 }
 394
 395 static char *xstrdup_tolower(const char *str)
 396 {
 397         char *p, *dup = xstrdup(str);
 398         for (p = dup; *p; p++)
 399                 *p = tolower(*p);
 400         return dup;
 401 }
 402
 403 static void parse_host_and_port(char *hostport, char **host,
 404         char **port)
 405 {
 406         if (*hostport == '[') {
 407                 char *end;
 408
 409                 end = strchr(hostport, ']');
 410                 if (!end)
 411                         die("Invalid request ('[' without ']')");
 412                 *end = '\0';
 413                 *host = hostport + 1;
 414                 if (!end[1])
 415                         *port = NULL;
 416                 else if (end[1] == ':')
 417                         *port = end + 2;
 418                 else
 419                         die("Garbage after end of host part");
 420         } else {
 421                 *host = hostport;
 422                 *port = strrchr(hostport, ':');
 423                 if (*port) {
 424                         **port = '\0';
 425                         ++*port;
 426                 }
 427         }
 428 }
 429
 430 /*
 431  * Read the host as supplied by the client connection.
 432  */
 433 static void parse_host_arg(char *extra_args, int buflen)
 434 {
 435         char *val;
 436         int vallen;
 437         char *end = extra_args + buflen;
 438
 439         if (extra_args < end && *extra_args) {
 440                 saw_extended_args = 1;
 441                 if (strncasecmp("host=", extra_args, 5) == 0) {
 442                         val = extra_args + 5;
 443                         vallen = strlen(val) + 1;
 444                         if (*val) {
 445                                 /* Split <host>:<port> at colon. */
 446                                 char *host;
 447                                 char *port;
 448                                 parse_host_and_port(val, &host, &port);
 449                                 if (port) {
 450                                         free(tcp_port);
 451                                         tcp_port = xstrdup(port);
 452                                 }
 453                                 free(hostname);
 454                                 hostname = xstrdup_tolower(host);
 455                         }
 456
 457                         /* On to the next one */
 458                         extra_args = val + vallen;
 459                 }
 460                 if (extra_args < end && *extra_args)
 461                         die("Invalid request");
 462         }
 463
 464         /*
 465          * Locate canonical hostname and its IP address.
 466          */
 467         if (hostname) {
 468 #ifndef NO_IPV6
 469                 struct addrinfo hints;
 470                 struct addrinfo *ai;
 471                 int gai;
 472                 static char addrbuf[HOST_NAME_MAX + 1];
 473
 474                 memset(&hints, 0, sizeof(hints));
 475                 hints.ai_flags = AI_CANONNAME;
 476
 477                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 478                 if (!gai) {
 479                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 480
 481                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 482                                   addrbuf, sizeof(addrbuf));
 483                         free(ip_address);
 484                         ip_address = xstrdup(addrbuf);
 485
 486                         free(canon_hostname);
 487                         canon_hostname = xstrdup(ai->ai_canonname ?
 488                                                  ai->ai_canonname : ip_address);
 489
 490                         freeaddrinfo(ai);
 491                 }
 492 #else
 493                 struct hostent *hent;
 494                 struct sockaddr_in sa;
 495                 char **ap;
 496                 static char addrbuf[HOST_NAME_MAX + 1];
 497
 498                 hent = gethostbyname(hostname);
 499
 500                 ap = hent->h_addr_list;
 501                 memset(&sa, 0, sizeof sa);
 502                 sa.sin_family = hent->h_addrtype;
 503                 sa.sin_port = htons(0);
 504                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 505
 506                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 507                           addrbuf, sizeof(addrbuf));
 508
 509                 free(canon_hostname);
 510                 canon_hostname = xstrdup(hent->h_name);
 511                 free(ip_address);
 512                 ip_address = xstrdup(addrbuf);
 513 #endif
 514         }
 515 }
 516
 517
 518 static int execute(struct sockaddr *addr)
 519 {
 520         static char line[1000];
 521         int pktlen, len, i;
 522
 523         if (addr) {
 524                 char addrbuf[256] = "";
 525                 int port = -1;
 526
 527                 if (addr->sa_family == AF_INET) {
 528                         struct sockaddr_in *sin_addr = (void *) addr;
 529                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 530                         port = ntohs(sin_addr->sin_port);
 531 #ifndef NO_IPV6
 532                 } else if (addr && addr->sa_family == AF_INET6) {
 533                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 534
 535                         char *buf = addrbuf;
 536                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 537                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 538                         strcat(buf, "]");
 539
 540                         port = ntohs(sin6_addr->sin6_port);
 541 #endif
 542                 }
 543                 loginfo("Connection from %s:%d", addrbuf, port);
 544                 setenv("REMOTE_ADDR", addrbuf, 1);
 545         }
 546         else {
 547                 unsetenv("REMOTE_ADDR");
 548         }
 549
 550         alarm(init_timeout ? init_timeout : timeout);
 551         pktlen = packet_read_line(0, line, sizeof(line));
 552         alarm(0);
 553
 554         len = strlen(line);
 555         if (pktlen != len)
 556                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 557                         (int) pktlen - len,
 558                         (int) pktlen - len, line + len + 1);
 559         if (len && line[len-1] == '\n') {
 560                 line[--len] = 0;
 561                 pktlen--;
 562         }
 563
 564         free(hostname);
 565         free(canon_hostname);
 566         free(ip_address);
 567         free(tcp_port);
 568         hostname = canon_hostname = ip_address = tcp_port = NULL;
 569
 570         if (len != pktlen)
 571                 parse_host_arg(line + len + 1, pktlen - len - 1);
 572
 573         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 574                 struct daemon_service *s = &(daemon_service[i]);
 575                 int namelen = strlen(s->name);
 576                 if (!prefixcmp(line, "git-") &&
 577                     !strncmp(s->name, line + 4, namelen) &&
 578                     line[namelen + 4] == ' ') {
 579                         /*
 580                          * Note: The directory here is probably context sensitive,
 581                          * and might depend on the actual service being performed.
 582                          */
 583                         return run_service(line + namelen + 5, s);
 584                 }
 585         }
 586
 587         logerror("Protocol error: '%s'", line);
 588         return -1;
 589 }
 590
 591 static int addrcmp(const struct sockaddr_storage *s1,
 592     const struct sockaddr_storage *s2)
 593 {
 594         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 595         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 596
 597         if (sa1->sa_family != sa2->sa_family)
 598                 return sa1->sa_family - sa2->sa_family;
 599         if (sa1->sa_family == AF_INET)
 600                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 601                     &((struct sockaddr_in *)s2)->sin_addr,
 602                     sizeof(struct in_addr));
 603 #ifndef NO_IPV6
 604         if (sa1->sa_family == AF_INET6)
 605                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 606                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 607                     sizeof(struct in6_addr));
 608 #endif
 609         return 0;
 610 }
 611
 612 static int max_connections = 32;
 613
 614 static unsigned int live_children;
 615
 616 static struct child {
 617         struct child *next;
 618         pid_t pid;
 619         struct sockaddr_storage address;
 620 } *firstborn;
 621
 622 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 623 {
 624         struct child *newborn, **cradle;
 625
 626         newborn = xcalloc(1, sizeof(*newborn));
 627         live_children++;
 628         newborn->pid = pid;
 629         memcpy(&newborn->address, addr, addrlen);
 630         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 631                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 632                         break;
 633         newborn->next = *cradle;
 634         *cradle = newborn;
 635 }
 636
 637 static void remove_child(pid_t pid)
 638 {
 639         struct child **cradle, *blanket;
 640
 641         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 642                 if (blanket->pid == pid) {
 643                         *cradle = blanket->next;
 644                         live_children--;
 645                         free(blanket);
 646                         break;
 647                 }
 648 }
 649
 650 /*
 651  * This gets called if the number of connections grows
 652  * past "max_connections".
 653  *
 654  * We kill the newest connection from a duplicate IP.
 655  */
 656 static void kill_some_child(void)
 657 {
 658         const struct child *blanket, *next;
 659
 660         if (!(blanket = firstborn))
 661                 return;
 662
 663         for (; (next = blanket->next); blanket = next)
 664                 if (!addrcmp(&blanket->address, &next->address)) {
 665                         kill(blanket->pid, SIGTERM);
 666                         break;
 667                 }
 668 }
 669
 670 static void check_dead_children(void)
 671 {
 672         int status;
 673         pid_t pid;
 674
 675         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 676                 const char *dead = "";
 677                 remove_child(pid);
 678                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 679                         dead = " (with error)";
 680                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 681         }
 682 }
 683
 684 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 685 {
 686         pid_t pid;
 687
 688         if (max_connections && live_children >= max_connections) {
 689                 kill_some_child();
 690                 sleep(1);  /* give it some time to die */
 691                 check_dead_children();
 692                 if (live_children >= max_connections) {
 693                         close(incoming);
 694                         logerror("Too many children, dropping connection");
 695                         return;
 696                 }
 697         }
 698
 699         if ((pid = fork())) {
 700                 close(incoming);
 701                 if (pid < 0) {
 702                         logerror("Couldn't fork %s", strerror(errno));
 703                         return;
 704                 }
 705
 706                 add_child(pid, addr, addrlen);
 707                 return;
 708         }
 709
 710         dup2(incoming, 0);
 711         dup2(incoming, 1);
 712         close(incoming);
 713
 714         exit(execute(addr));
 715 }
 716
 717 static void child_handler(int signo)
 718 {
 719         /*
 720          * Otherwise empty handler because systemcalls will get interrupted
 721          * upon signal receipt
 722          * SysV needs the handler to be rearmed
 723          */
 724         signal(SIGCHLD, child_handler);
 725 }
 726
 727 static int set_reuse_addr(int sockfd)
 728 {
 729         int on = 1;
 730
 731         if (!reuseaddr)
 732                 return 0;
 733         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 734                           &on, sizeof(on));
 735 }
 736
 737 struct socketlist {
 738         int *list;
 739         size_t nr;
 740         size_t alloc;
 741 };
 742
 743 #ifndef NO_IPV6
 744
 745 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 746 {
 747         int socknum = 0;
 748         int maxfd = -1;
 749         char pbuf[NI_MAXSERV];
 750         struct addrinfo hints, *ai0, *ai;
 751         int gai;
 752         long flags;
 753
 754         sprintf(pbuf, "%d", listen_port);
 755         memset(&hints, 0, sizeof(hints));
 756         hints.ai_family = AF_UNSPEC;
 757         hints.ai_socktype = SOCK_STREAM;
 758         hints.ai_protocol = IPPROTO_TCP;
 759         hints.ai_flags = AI_PASSIVE;
 760
 761         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 762         if (gai) {
 763                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 764                 return 0;
 765         }
 766
 767         for (ai = ai0; ai; ai = ai->ai_next) {
 768                 int sockfd;
 769
 770                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 771                 if (sockfd < 0)
 772                         continue;
 773                 if (sockfd >= FD_SETSIZE) {
 774                         logerror("Socket descriptor too large");
 775                         close(sockfd);
 776                         continue;
 777                 }
 778
 779 #ifdef IPV6_V6ONLY
 780                 if (ai->ai_family == AF_INET6) {
 781                         int on = 1;
 782                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 783                                    &on, sizeof(on));
 784                         /* Note: error is not fatal */
 785                 }
 786 #endif
 787
 788                 if (set_reuse_addr(sockfd)) {
 789                         close(sockfd);
 790                         continue;
 791                 }
 792
 793                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 794                         close(sockfd);
 795                         continue;       /* not fatal */
 796                 }
 797                 if (listen(sockfd, 5) < 0) {
 798                         close(sockfd);
 799                         continue;       /* not fatal */
 800                 }
 801
 802                 flags = fcntl(sockfd, F_GETFD, 0);
 803                 if (flags >= 0)
 804                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 805
 806                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 807                 socklist->list[socklist->nr++] = sockfd;
 808                 socknum++;
 809
 810                 if (maxfd < sockfd)
 811                         maxfd = sockfd;
 812         }
 813
 814         freeaddrinfo(ai0);
 815
 816         return socknum;
 817 }
 818
 819 #else /* NO_IPV6 */
 820
 821 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 822 {
 823         struct sockaddr_in sin;
 824         int sockfd;
 825         long flags;
 826
 827         memset(&sin, 0, sizeof sin);
 828         sin.sin_family = AF_INET;
 829         sin.sin_port = htons(listen_port);
 830
 831         if (listen_addr) {
 832                 /* Well, host better be an IP address here. */
 833                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 834                         return 0;
 835         } else {
 836                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 837         }
 838
 839         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 840         if (sockfd < 0)
 841                 return 0;
 842
 843         if (set_reuse_addr(sockfd)) {
 844                 close(sockfd);
 845                 return 0;
 846         }
 847
 848         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 849                 close(sockfd);
 850                 return 0;
 851         }
 852
 853         if (listen(sockfd, 5) < 0) {
 854                 close(sockfd);
 855                 return 0;
 856         }
 857
 858         flags = fcntl(sockfd, F_GETFD, 0);
 859         if (flags >= 0)
 860                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 861
 862         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 863         socklist->list[socklist->nr++] = sockfd;
 864         return 1;
 865 }
 866
 867 #endif
 868
 869 static void socksetup(char *listen_addr, int listen_port, struct socketlist *socklist)
 870 {
 871         setup_named_sock(listen_addr, listen_port, socklist);
 872 }
 873
 874 static int service_loop(struct socketlist *socklist)
 875 {
 876         struct pollfd *pfd;
 877         int i;
 878
 879         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 880
 881         for (i = 0; i < socklist->nr; i++) {
 882                 pfd[i].fd = socklist->list[i];
 883                 pfd[i].events = POLLIN;
 884         }
 885
 886         signal(SIGCHLD, child_handler);
 887
 888         for (;;) {
 889                 int i;
 890
 891                 check_dead_children();
 892
 893                 if (poll(pfd, socklist->nr, -1) < 0) {
 894                         if (errno != EINTR) {
 895                                 logerror("Poll failed, resuming: %s",
 896                                       strerror(errno));
 897                                 sleep(1);
 898                         }
 899                         continue;
 900                 }
 901
 902                 for (i = 0; i < socklist->nr; i++) {
 903                         if (pfd[i].revents & POLLIN) {
 904                                 struct sockaddr_storage ss;
 905                                 unsigned int sslen = sizeof(ss);
 906                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 907                                 if (incoming < 0) {
 908                                         switch (errno) {
 909                                         case EAGAIN:
 910                                         case EINTR:
 911                                         case ECONNABORTED:
 912                                                 continue;
 913                                         default:
 914                                                 die_errno("accept returned");
 915                                         }
 916                                 }
 917                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 918                         }
 919                 }
 920         }
 921 }
 922
 923 /* if any standard file descriptor is missing open it to /dev/null */
 924 static void sanitize_stdfds(void)
 925 {
 926         int fd = open("/dev/null", O_RDWR, 0);
 927         while (fd != -1 && fd < 2)
 928                 fd = dup(fd);
 929         if (fd == -1)
 930                 die_errno("open /dev/null or dup failed");
 931         if (fd > 2)
 932                 close(fd);
 933 }
 934
 935 static void daemonize(void)
 936 {
 937         switch (fork()) {
 938                 case 0:
 939                         break;
 940                 case -1:
 941                         die_errno("fork failed");
 942                 default:
 943                         exit(0);
 944         }
 945         if (setsid() == -1)
 946                 die_errno("setsid failed");
 947         close(0);
 948         close(1);
 949         close(2);
 950         sanitize_stdfds();
 951 }
 952
 953 static void store_pid(const char *path)
 954 {
 955         FILE *f = fopen(path, "w");
 956         if (!f)
 957                 die_errno("cannot open pid file '%s'", path);
 958         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 959                 die_errno("failed to write pid file '%s'", path);
 960 }
 961
 962 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 963 {
 964         struct socketlist socklist = { NULL, 0, 0 };
 965
 966         socksetup(listen_addr, listen_port, &socklist);
 967         if (socklist.nr == 0)
 968                 die("unable to allocate any listen sockets on host %s port %u",
 969                     listen_addr, listen_port);
 970
 971         if (pass && gid &&
 972             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 973              setuid(pass->pw_uid)))
 974                 die("cannot drop privileges");
 975
 976         return service_loop(&socklist);
 977 }
 978
 979 int main(int argc, char **argv)
 980 {
 981         int listen_port = 0;
 982         char *listen_addr = NULL;
 983         int inetd_mode = 0;
 984         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 985         int detach = 0;
 986         struct passwd *pass = NULL;
 987         struct group *group;
 988         gid_t gid = 0;
 989         int i;
 990
 991         git_extract_argv0_path(argv[0]);
 992
 993         for (i = 1; i < argc; i++) {
 994                 char *arg = argv[i];
 995
 996                 if (!prefixcmp(arg, "--listen=")) {
 997                         listen_addr = xstrdup_tolower(arg + 9);
 998                         continue;
 999                 }
1000                 if (!prefixcmp(arg, "--port=")) {
1001                         char *end;
1002                         unsigned long n;
1003                         n = strtoul(arg+7, &end, 0);
1004                         if (arg[7] && !*end) {
1005                                 listen_port = n;
1006                                 continue;
1007                         }
1008                 }
1009                 if (!strcmp(arg, "--inetd")) {
1010                         inetd_mode = 1;
1011                         log_syslog = 1;
1012                         continue;
1013                 }
1014                 if (!strcmp(arg, "--verbose")) {
1015                         verbose = 1;
1016                         continue;
1017                 }
1018                 if (!strcmp(arg, "--syslog")) {
1019                         log_syslog = 1;
1020                         continue;
1021                 }
1022                 if (!strcmp(arg, "--export-all")) {
1023                         export_all_trees = 1;
1024                         continue;
1025                 }
1026                 if (!prefixcmp(arg, "--timeout=")) {
1027                         timeout = atoi(arg+10);
1028                         continue;
1029                 }
1030                 if (!prefixcmp(arg, "--init-timeout=")) {
1031                         init_timeout = atoi(arg+15);
1032                         continue;
1033                 }
1034                 if (!prefixcmp(arg, "--max-connections=")) {
1035                         max_connections = atoi(arg+18);
1036                         if (max_connections < 0)
1037                                 max_connections = 0;            /* unlimited */
1038                         continue;
1039                 }
1040                 if (!strcmp(arg, "--strict-paths")) {
1041                         strict_paths = 1;
1042                         continue;
1043                 }
1044                 if (!prefixcmp(arg, "--base-path=")) {
1045                         base_path = arg+12;
1046                         continue;
1047                 }
1048                 if (!strcmp(arg, "--base-path-relaxed")) {
1049                         base_path_relaxed = 1;
1050                         continue;
1051                 }
1052                 if (!prefixcmp(arg, "--interpolated-path=")) {
1053                         interpolated_path = arg+20;
1054                         continue;
1055                 }
1056                 if (!strcmp(arg, "--reuseaddr")) {
1057                         reuseaddr = 1;
1058                         continue;
1059                 }
1060                 if (!strcmp(arg, "--user-path")) {
1061                         user_path = "";
1062                         continue;
1063                 }
1064                 if (!prefixcmp(arg, "--user-path=")) {
1065                         user_path = arg + 12;
1066                         continue;
1067                 }
1068                 if (!prefixcmp(arg, "--pid-file=")) {
1069                         pid_file = arg + 11;
1070                         continue;
1071                 }
1072                 if (!strcmp(arg, "--detach")) {
1073                         detach = 1;
1074                         log_syslog = 1;
1075                         continue;
1076                 }
1077                 if (!prefixcmp(arg, "--user=")) {
1078                         user_name = arg + 7;
1079                         continue;
1080                 }
1081                 if (!prefixcmp(arg, "--group=")) {
1082                         group_name = arg + 8;
1083                         continue;
1084                 }
1085                 if (!prefixcmp(arg, "--enable=")) {
1086                         enable_service(arg + 9, 1);
1087                         continue;
1088                 }
1089                 if (!prefixcmp(arg, "--disable=")) {
1090                         enable_service(arg + 10, 0);
1091                         continue;
1092                 }
1093                 if (!prefixcmp(arg, "--allow-override=")) {
1094                         make_service_overridable(arg + 17, 1);
1095                         continue;
1096                 }
1097                 if (!prefixcmp(arg, "--forbid-override=")) {
1098                         make_service_overridable(arg + 18, 0);
1099                         continue;
1100                 }
1101                 if (!strcmp(arg, "--")) {
1102                         ok_paths = &argv[i+1];
1103                         break;
1104                 } else if (arg[0] != '-') {
1105                         ok_paths = &argv[i];
1106                         break;
1107                 }
1108
1109                 usage(daemon_usage);
1110         }
1111
1112         if (log_syslog) {
1113                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1114                 set_die_routine(daemon_die);
1115         } else
1116                 /* avoid splitting a message in the middle */
1117                 setvbuf(stderr, NULL, _IOLBF, 0);
1118
1119         if (inetd_mode && (group_name || user_name))
1120                 die("--user and --group are incompatible with --inetd");
1121
1122         if (inetd_mode && (listen_port || listen_addr))
1123                 die("--listen= and --port= are incompatible with --inetd");
1124         else if (listen_port == 0)
1125                 listen_port = DEFAULT_GIT_PORT;
1126
1127         if (group_name && !user_name)
1128                 die("--group supplied without --user");
1129
1130         if (user_name) {
1131                 pass = getpwnam(user_name);
1132                 if (!pass)
1133                         die("user not found - %s", user_name);
1134
1135                 if (!group_name)
1136                         gid = pass->pw_gid;
1137                 else {
1138                         group = getgrnam(group_name);
1139                         if (!group)
1140                                 die("group not found - %s", group_name);
1141
1142                         gid = group->gr_gid;
1143                 }
1144         }
1145
1146         if (strict_paths && (!ok_paths || !*ok_paths))
1147                 die("option --strict-paths requires a whitelist");
1148
1149         if (base_path && !is_directory(base_path))
1150                 die("base-path '%s' does not exist or is not a directory",
1151                     base_path);
1152
1153         if (inetd_mode) {
1154                 struct sockaddr_storage ss;
1155                 struct sockaddr *peer = (struct sockaddr *)&ss;
1156                 socklen_t slen = sizeof(ss);
1157
1158                 if (!freopen("/dev/null", "w", stderr))
1159                         die_errno("failed to redirect stderr to /dev/null");
1160
1161                 if (getpeername(0, peer, &slen))
1162                         peer = NULL;
1163
1164                 return execute(peer);
1165         }
1166
1167         if (detach) {
1168                 daemonize();
1169                 loginfo("Ready to rumble");
1170         }
1171         else
1172                 sanitize_stdfds();
1173
1174         if (pid_file)
1175                 store_pid(pid_file);
1176
1177         return serve(listen_addr, listen_port, pass, gid);
1178 }