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