daemon.c

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