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                 return -1;
 261         }
 262
 263         if (!(path = path_ok(dir)))
 264                 return -1;
 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                 return -1;
 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                 return -1;
 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
 306 static void copy_to_log(int fd)
 307 {
 308         struct strbuf line = STRBUF_INIT;
 309         FILE *fp;
 310
 311         fp = fdopen(fd, "r");
 312         if (fp == NULL) {
 313                 logerror("fdopen of error channel failed");
 314                 close(fd);
 315                 return;
 316         }
 317
 318         while (strbuf_getline(&line, fp, '\n') != EOF) {
 319                 logerror("%s", line.buf);
 320                 strbuf_setlen(&line, 0);
 321         }
 322
 323         strbuf_release(&line);
 324         fclose(fp);
 325 }
 326
 327 static int run_service_command(const char **argv)
 328 {
 329         struct child_process cld;
 330
 331         memset(&cld, 0, sizeof(cld));
 332         cld.argv = argv;
 333         cld.git_cmd = 1;
 334         cld.err = -1;
 335         if (start_command(&cld))
 336                 return -1;
 337
 338         close(0);
 339         close(1);
 340
 341         copy_to_log(cld.err);
 342
 343         return finish_command(&cld);
 344 }
 345
 346 static int upload_pack(void)
 347 {
 348         /* Timeout as string */
 349         char timeout_buf[64];
 350         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 351
 352         argv[2] = timeout_buf;
 353
 354         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 355         return run_service_command(argv);
 356 }
 357
 358 static int upload_archive(void)
 359 {
 360         static const char *argv[] = { "upload-archive", ".", NULL };
 361         return run_service_command(argv);
 362 }
 363
 364 static int receive_pack(void)
 365 {
 366         static const char *argv[] = { "receive-pack", ".", NULL };
 367         return run_service_command(argv);
 368 }
 369
 370 static struct daemon_service daemon_service[] = {
 371         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 372         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 373         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 374 };
 375
 376 static void enable_service(const char *name, int ena)
 377 {
 378         int i;
 379         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 380                 if (!strcmp(daemon_service[i].name, name)) {
 381                         daemon_service[i].enabled = ena;
 382                         return;
 383                 }
 384         }
 385         die("No such service %s", name);
 386 }
 387
 388 static void make_service_overridable(const char *name, int ena)
 389 {
 390         int i;
 391         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 392                 if (!strcmp(daemon_service[i].name, name)) {
 393                         daemon_service[i].overridable = ena;
 394                         return;
 395                 }
 396         }
 397         die("No such service %s", name);
 398 }
 399
 400 static char *xstrdup_tolower(const char *str)
 401 {
 402         char *p, *dup = xstrdup(str);
 403         for (p = dup; *p; p++)
 404                 *p = tolower(*p);
 405         return dup;
 406 }
 407
 408 static void parse_host_and_port(char *hostport, char **host,
 409         char **port)
 410 {
 411         if (*hostport == '[') {
 412                 char *end;
 413
 414                 end = strchr(hostport, ']');
 415                 if (!end)
 416                         die("Invalid request ('[' without ']')");
 417                 *end = '\0';
 418                 *host = hostport + 1;
 419                 if (!end[1])
 420                         *port = NULL;
 421                 else if (end[1] == ':')
 422                         *port = end + 2;
 423                 else
 424                         die("Garbage after end of host part");
 425         } else {
 426                 *host = hostport;
 427                 *port = strrchr(hostport, ':');
 428                 if (*port) {
 429                         **port = '\0';
 430                         ++*port;
 431                 }
 432         }
 433 }
 434
 435 /*
 436  * Read the host as supplied by the client connection.
 437  */
 438 static void parse_host_arg(char *extra_args, int buflen)
 439 {
 440         char *val;
 441         int vallen;
 442         char *end = extra_args + buflen;
 443
 444         if (extra_args < end && *extra_args) {
 445                 saw_extended_args = 1;
 446                 if (strncasecmp("host=", extra_args, 5) == 0) {
 447                         val = extra_args + 5;
 448                         vallen = strlen(val) + 1;
 449                         if (*val) {
 450                                 /* Split <host>:<port> at colon. */
 451                                 char *host;
 452                                 char *port;
 453                                 parse_host_and_port(val, &host, &port);
 454                                 if (port) {
 455                                         free(tcp_port);
 456                                         tcp_port = xstrdup(port);
 457                                 }
 458                                 free(hostname);
 459                                 hostname = xstrdup_tolower(host);
 460                         }
 461
 462                         /* On to the next one */
 463                         extra_args = val + vallen;
 464                 }
 465                 if (extra_args < end && *extra_args)
 466                         die("Invalid request");
 467         }
 468
 469         /*
 470          * Locate canonical hostname and its IP address.
 471          */
 472         if (hostname) {
 473 #ifndef NO_IPV6
 474                 struct addrinfo hints;
 475                 struct addrinfo *ai;
 476                 int gai;
 477                 static char addrbuf[HOST_NAME_MAX + 1];
 478
 479                 memset(&hints, 0, sizeof(hints));
 480                 hints.ai_flags = AI_CANONNAME;
 481
 482                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 483                 if (!gai) {
 484                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 485
 486                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 487                                   addrbuf, sizeof(addrbuf));
 488                         free(ip_address);
 489                         ip_address = xstrdup(addrbuf);
 490
 491                         free(canon_hostname);
 492                         canon_hostname = xstrdup(ai->ai_canonname ?
 493                                                  ai->ai_canonname : ip_address);
 494
 495                         freeaddrinfo(ai);
 496                 }
 497 #else
 498                 struct hostent *hent;
 499                 struct sockaddr_in sa;
 500                 char **ap;
 501                 static char addrbuf[HOST_NAME_MAX + 1];
 502
 503                 hent = gethostbyname(hostname);
 504
 505                 ap = hent->h_addr_list;
 506                 memset(&sa, 0, sizeof sa);
 507                 sa.sin_family = hent->h_addrtype;
 508                 sa.sin_port = htons(0);
 509                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 510
 511                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 512                           addrbuf, sizeof(addrbuf));
 513
 514                 free(canon_hostname);
 515                 canon_hostname = xstrdup(hent->h_name);
 516                 free(ip_address);
 517                 ip_address = xstrdup(addrbuf);
 518 #endif
 519         }
 520 }
 521
 522
 523 static int execute(void)
 524 {
 525         static char line[1000];
 526         int pktlen, len, i;
 527         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 528
 529         if (addr)
 530                 loginfo("Connection from %s:%s", addr, port);
 531
 532         alarm(init_timeout ? init_timeout : timeout);
 533         pktlen = packet_read_line(0, line, sizeof(line));
 534         alarm(0);
 535
 536         len = strlen(line);
 537         if (pktlen != len)
 538                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 539                         (int) pktlen - len,
 540                         (int) pktlen - len, line + len + 1);
 541         if (len && line[len-1] == '\n') {
 542                 line[--len] = 0;
 543                 pktlen--;
 544         }
 545
 546         free(hostname);
 547         free(canon_hostname);
 548         free(ip_address);
 549         free(tcp_port);
 550         hostname = canon_hostname = ip_address = tcp_port = NULL;
 551
 552         if (len != pktlen)
 553                 parse_host_arg(line + len + 1, pktlen - len - 1);
 554
 555         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 556                 struct daemon_service *s = &(daemon_service[i]);
 557                 int namelen = strlen(s->name);
 558                 if (!prefixcmp(line, "git-") &&
 559                     !strncmp(s->name, line + 4, namelen) &&
 560                     line[namelen + 4] == ' ') {
 561                         /*
 562                          * Note: The directory here is probably context sensitive,
 563                          * and might depend on the actual service being performed.
 564                          */
 565                         return run_service(line + namelen + 5, s);
 566                 }
 567         }
 568
 569         logerror("Protocol error: '%s'", line);
 570         return -1;
 571 }
 572
 573 static int addrcmp(const struct sockaddr_storage *s1,
 574     const struct sockaddr_storage *s2)
 575 {
 576         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 577         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 578
 579         if (sa1->sa_family != sa2->sa_family)
 580                 return sa1->sa_family - sa2->sa_family;
 581         if (sa1->sa_family == AF_INET)
 582                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 583                     &((struct sockaddr_in *)s2)->sin_addr,
 584                     sizeof(struct in_addr));
 585 #ifndef NO_IPV6
 586         if (sa1->sa_family == AF_INET6)
 587                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 588                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 589                     sizeof(struct in6_addr));
 590 #endif
 591         return 0;
 592 }
 593
 594 static int max_connections = 32;
 595
 596 static unsigned int live_children;
 597
 598 static struct child {
 599         struct child *next;
 600         struct child_process cld;
 601         struct sockaddr_storage address;
 602 } *firstborn;
 603
 604 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 605 {
 606         struct child *newborn, **cradle;
 607
 608         newborn = xcalloc(1, sizeof(*newborn));
 609         live_children++;
 610         memcpy(&newborn->cld, cld, sizeof(*cld));
 611         memcpy(&newborn->address, addr, addrlen);
 612         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 613                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 614                         break;
 615         newborn->next = *cradle;
 616         *cradle = newborn;
 617 }
 618
 619 /*
 620  * This gets called if the number of connections grows
 621  * past "max_connections".
 622  *
 623  * We kill the newest connection from a duplicate IP.
 624  */
 625 static void kill_some_child(void)
 626 {
 627         const struct child *blanket, *next;
 628
 629         if (!(blanket = firstborn))
 630                 return;
 631
 632         for (; (next = blanket->next); blanket = next)
 633                 if (!addrcmp(&blanket->address, &next->address)) {
 634                         kill(blanket->cld.pid, SIGTERM);
 635                         break;
 636                 }
 637 }
 638
 639 static void check_dead_children(void)
 640 {
 641         int status;
 642         pid_t pid;
 643
 644         struct child **cradle, *blanket;
 645         for (cradle = &firstborn; (blanket = *cradle);)
 646                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 647                         const char *dead = "";
 648                         if (status)
 649                                 dead = " (with error)";
 650                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 651
 652                         /* remove the child */
 653                         *cradle = blanket->next;
 654                         live_children--;
 655                         free(blanket);
 656                 } else
 657                         cradle = &blanket->next;
 658 }
 659
 660 static char **cld_argv;
 661 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 662 {
 663         struct child_process cld = { NULL };
 664         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 665         char *env[] = { addrbuf, portbuf, NULL };
 666
 667         if (max_connections && live_children >= max_connections) {
 668                 kill_some_child();
 669                 sleep(1);  /* give it some time to die */
 670                 check_dead_children();
 671                 if (live_children >= max_connections) {
 672                         close(incoming);
 673                         logerror("Too many children, dropping connection");
 674                         return;
 675                 }
 676         }
 677
 678         if (addr->sa_family == AF_INET) {
 679                 struct sockaddr_in *sin_addr = (void *) addr;
 680                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 681                     sizeof(addrbuf) - 12);
 682                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 683                     ntohs(sin_addr->sin_port));
 684 #ifndef NO_IPV6
 685         } else if (addr && addr->sa_family == AF_INET6) {
 686                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 687
 688                 char *buf = addrbuf + 12;
 689                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 690                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 691                     sizeof(addrbuf) - 13);
 692                 strcat(buf, "]");
 693
 694                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 695                     ntohs(sin6_addr->sin6_port));
 696 #endif
 697         }
 698
 699         cld.env = (const char **)env;
 700         cld.argv = (const char **)cld_argv;
 701         cld.in = incoming;
 702         cld.out = dup(incoming);
 703
 704         if (start_command(&cld))
 705                 logerror("unable to fork");
 706         else
 707                 add_child(&cld, addr, addrlen);
 708         close(incoming);
 709 }
 710
 711 static void child_handler(int signo)
 712 {
 713         /*
 714          * Otherwise empty handler because systemcalls will get interrupted
 715          * upon signal receipt
 716          * SysV needs the handler to be rearmed
 717          */
 718         signal(SIGCHLD, child_handler);
 719 }
 720
 721 static int set_reuse_addr(int sockfd)
 722 {
 723         int on = 1;
 724
 725         if (!reuseaddr)
 726                 return 0;
 727         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 728                           &on, sizeof(on));
 729 }
 730
 731 struct socketlist {
 732         int *list;
 733         size_t nr;
 734         size_t alloc;
 735 };
 736
 737 #ifndef NO_IPV6
 738
 739 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 740 {
 741         int socknum = 0;
 742         int maxfd = -1;
 743         char pbuf[NI_MAXSERV];
 744         struct addrinfo hints, *ai0, *ai;
 745         int gai;
 746         long flags;
 747
 748         sprintf(pbuf, "%d", listen_port);
 749         memset(&hints, 0, sizeof(hints));
 750         hints.ai_family = AF_UNSPEC;
 751         hints.ai_socktype = SOCK_STREAM;
 752         hints.ai_protocol = IPPROTO_TCP;
 753         hints.ai_flags = AI_PASSIVE;
 754
 755         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 756         if (gai) {
 757                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 758                 return 0;
 759         }
 760
 761         for (ai = ai0; ai; ai = ai->ai_next) {
 762                 int sockfd;
 763
 764                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 765                 if (sockfd < 0)
 766                         continue;
 767                 if (sockfd >= FD_SETSIZE) {
 768                         logerror("Socket descriptor too large");
 769                         close(sockfd);
 770                         continue;
 771                 }
 772
 773 #ifdef IPV6_V6ONLY
 774                 if (ai->ai_family == AF_INET6) {
 775                         int on = 1;
 776                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 777                                    &on, sizeof(on));
 778                         /* Note: error is not fatal */
 779                 }
 780 #endif
 781
 782                 if (set_reuse_addr(sockfd)) {
 783                         close(sockfd);
 784                         continue;
 785                 }
 786
 787                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 788                         close(sockfd);
 789                         continue;       /* not fatal */
 790                 }
 791                 if (listen(sockfd, 5) < 0) {
 792                         close(sockfd);
 793                         continue;       /* not fatal */
 794                 }
 795
 796                 flags = fcntl(sockfd, F_GETFD, 0);
 797                 if (flags >= 0)
 798                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 799
 800                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 801                 socklist->list[socklist->nr++] = sockfd;
 802                 socknum++;
 803
 804                 if (maxfd < sockfd)
 805                         maxfd = sockfd;
 806         }
 807
 808         freeaddrinfo(ai0);
 809
 810         return socknum;
 811 }
 812
 813 #else /* NO_IPV6 */
 814
 815 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 816 {
 817         struct sockaddr_in sin;
 818         int sockfd;
 819         long flags;
 820
 821         memset(&sin, 0, sizeof sin);
 822         sin.sin_family = AF_INET;
 823         sin.sin_port = htons(listen_port);
 824
 825         if (listen_addr) {
 826                 /* Well, host better be an IP address here. */
 827                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 828                         return 0;
 829         } else {
 830                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 831         }
 832
 833         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 834         if (sockfd < 0)
 835                 return 0;
 836
 837         if (set_reuse_addr(sockfd)) {
 838                 close(sockfd);
 839                 return 0;
 840         }
 841
 842         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 843                 close(sockfd);
 844                 return 0;
 845         }
 846
 847         if (listen(sockfd, 5) < 0) {
 848                 close(sockfd);
 849                 return 0;
 850         }
 851
 852         flags = fcntl(sockfd, F_GETFD, 0);
 853         if (flags >= 0)
 854                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 855
 856         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 857         socklist->list[socklist->nr++] = sockfd;
 858         return 1;
 859 }
 860
 861 #endif
 862
 863 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 864 {
 865         if (!listen_addr->nr)
 866                 setup_named_sock(NULL, listen_port, socklist);
 867         else {
 868                 int i, socknum;
 869                 for (i = 0; i < listen_addr->nr; i++) {
 870                         socknum = setup_named_sock(listen_addr->items[i].string,
 871                                                    listen_port, socklist);
 872
 873                         if (socknum == 0)
 874                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 875                                          listen_addr->items[i].string, listen_port);
 876                 }
 877         }
 878 }
 879
 880 static int service_loop(struct socketlist *socklist)
 881 {
 882         struct pollfd *pfd;
 883         int i;
 884
 885         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 886
 887         for (i = 0; i < socklist->nr; i++) {
 888                 pfd[i].fd = socklist->list[i];
 889                 pfd[i].events = POLLIN;
 890         }
 891
 892         signal(SIGCHLD, child_handler);
 893
 894         for (;;) {
 895                 int i;
 896
 897                 check_dead_children();
 898
 899                 if (poll(pfd, socklist->nr, -1) < 0) {
 900                         if (errno != EINTR) {
 901                                 logerror("Poll failed, resuming: %s",
 902                                       strerror(errno));
 903                                 sleep(1);
 904                         }
 905                         continue;
 906                 }
 907
 908                 for (i = 0; i < socklist->nr; i++) {
 909                         if (pfd[i].revents & POLLIN) {
 910                                 union {
 911                                         struct sockaddr sa;
 912                                         struct sockaddr_in sai;
 913 #ifndef NO_IPV6
 914                                         struct sockaddr_in6 sai6;
 915 #endif
 916                                 } ss;
 917                                 socklen_t sslen = sizeof(ss);
 918                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
 919                                 if (incoming < 0) {
 920                                         switch (errno) {
 921                                         case EAGAIN:
 922                                         case EINTR:
 923                                         case ECONNABORTED:
 924                                                 continue;
 925                                         default:
 926                                                 die_errno("accept returned");
 927                                         }
 928                                 }
 929                                 handle(incoming, &ss.sa, sslen);
 930                         }
 931                 }
 932         }
 933 }
 934
 935 /* if any standard file descriptor is missing open it to /dev/null */
 936 static void sanitize_stdfds(void)
 937 {
 938         int fd = open("/dev/null", O_RDWR, 0);
 939         while (fd != -1 && fd < 2)
 940                 fd = dup(fd);
 941         if (fd == -1)
 942                 die_errno("open /dev/null or dup failed");
 943         if (fd > 2)
 944                 close(fd);
 945 }
 946
 947 #ifdef NO_POSIX_GOODIES
 948
 949 struct credentials;
 950
 951 static void drop_privileges(struct credentials *cred)
 952 {
 953         /* nothing */
 954 }
 955
 956 static void daemonize(void)
 957 {
 958         die("--detach not supported on this platform");
 959 }
 960
 961 static struct credentials *prepare_credentials(const char *user_name,
 962     const char *group_name)
 963 {
 964         die("--user not supported on this platform");
 965 }
 966
 967 #else
 968
 969 struct credentials {
 970         struct passwd *pass;
 971         gid_t gid;
 972 };
 973
 974 static void drop_privileges(struct credentials *cred)
 975 {
 976         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
 977             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
 978                 die("cannot drop privileges");
 979 }
 980
 981 static struct credentials *prepare_credentials(const char *user_name,
 982     const char *group_name)
 983 {
 984         static struct credentials c;
 985
 986         c.pass = getpwnam(user_name);
 987         if (!c.pass)
 988                 die("user not found - %s", user_name);
 989
 990         if (!group_name)
 991                 c.gid = c.pass->pw_gid;
 992         else {
 993                 struct group *group = getgrnam(group_name);
 994                 if (!group)
 995                         die("group not found - %s", group_name);
 996
 997                 c.gid = group->gr_gid;
 998         }
 999
1000         return &c;
1001 }
1002
1003 static void daemonize(void)
1004 {
1005         switch (fork()) {
1006                 case 0:
1007                         break;
1008                 case -1:
1009                         die_errno("fork failed");
1010                 default:
1011                         exit(0);
1012         }
1013         if (setsid() == -1)
1014                 die_errno("setsid failed");
1015         close(0);
1016         close(1);
1017         close(2);
1018         sanitize_stdfds();
1019 }
1020 #endif
1021
1022 static void store_pid(const char *path)
1023 {
1024         FILE *f = fopen(path, "w");
1025         if (!f)
1026                 die_errno("cannot open pid file '%s'", path);
1027         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1028                 die_errno("failed to write pid file '%s'", path);
1029 }
1030
1031 static int serve(struct string_list *listen_addr, int listen_port,
1032     struct credentials *cred)
1033 {
1034         struct socketlist socklist = { NULL, 0, 0 };
1035
1036         socksetup(listen_addr, listen_port, &socklist);
1037         if (socklist.nr == 0)
1038                 die("unable to allocate any listen sockets on port %u",
1039                     listen_port);
1040
1041         drop_privileges(cred);
1042
1043         return service_loop(&socklist);
1044 }
1045
1046 int main(int argc, char **argv)
1047 {
1048         int listen_port = 0;
1049         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1050         int serve_mode = 0, inetd_mode = 0;
1051         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1052         int detach = 0;
1053         struct credentials *cred = NULL;
1054         int i;
1055
1056         git_extract_argv0_path(argv[0]);
1057
1058         for (i = 1; i < argc; i++) {
1059                 char *arg = argv[i];
1060
1061                 if (!prefixcmp(arg, "--listen=")) {
1062                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1063                         continue;
1064                 }
1065                 if (!prefixcmp(arg, "--port=")) {
1066                         char *end;
1067                         unsigned long n;
1068                         n = strtoul(arg+7, &end, 0);
1069                         if (arg[7] && !*end) {
1070                                 listen_port = n;
1071                                 continue;
1072                         }
1073                 }
1074                 if (!strcmp(arg, "--serve")) {
1075                         serve_mode = 1;
1076                         continue;
1077                 }
1078                 if (!strcmp(arg, "--inetd")) {
1079                         inetd_mode = 1;
1080                         log_syslog = 1;
1081                         continue;
1082                 }
1083                 if (!strcmp(arg, "--verbose")) {
1084                         verbose = 1;
1085                         continue;
1086                 }
1087                 if (!strcmp(arg, "--syslog")) {
1088                         log_syslog = 1;
1089                         continue;
1090                 }
1091                 if (!strcmp(arg, "--export-all")) {
1092                         export_all_trees = 1;
1093                         continue;
1094                 }
1095                 if (!prefixcmp(arg, "--timeout=")) {
1096                         timeout = atoi(arg+10);
1097                         continue;
1098                 }
1099                 if (!prefixcmp(arg, "--init-timeout=")) {
1100                         init_timeout = atoi(arg+15);
1101                         continue;
1102                 }
1103                 if (!prefixcmp(arg, "--max-connections=")) {
1104                         max_connections = atoi(arg+18);
1105                         if (max_connections < 0)
1106                                 max_connections = 0;            /* unlimited */
1107                         continue;
1108                 }
1109                 if (!strcmp(arg, "--strict-paths")) {
1110                         strict_paths = 1;
1111                         continue;
1112                 }
1113                 if (!prefixcmp(arg, "--base-path=")) {
1114                         base_path = arg+12;
1115                         continue;
1116                 }
1117                 if (!strcmp(arg, "--base-path-relaxed")) {
1118                         base_path_relaxed = 1;
1119                         continue;
1120                 }
1121                 if (!prefixcmp(arg, "--interpolated-path=")) {
1122                         interpolated_path = arg+20;
1123                         continue;
1124                 }
1125                 if (!strcmp(arg, "--reuseaddr")) {
1126                         reuseaddr = 1;
1127                         continue;
1128                 }
1129                 if (!strcmp(arg, "--user-path")) {
1130                         user_path = "";
1131                         continue;
1132                 }
1133                 if (!prefixcmp(arg, "--user-path=")) {
1134                         user_path = arg + 12;
1135                         continue;
1136                 }
1137                 if (!prefixcmp(arg, "--pid-file=")) {
1138                         pid_file = arg + 11;
1139                         continue;
1140                 }
1141                 if (!strcmp(arg, "--detach")) {
1142                         detach = 1;
1143                         log_syslog = 1;
1144                         continue;
1145                 }
1146                 if (!prefixcmp(arg, "--user=")) {
1147                         user_name = arg + 7;
1148                         continue;
1149                 }
1150                 if (!prefixcmp(arg, "--group=")) {
1151                         group_name = arg + 8;
1152                         continue;
1153                 }
1154                 if (!prefixcmp(arg, "--enable=")) {
1155                         enable_service(arg + 9, 1);
1156                         continue;
1157                 }
1158                 if (!prefixcmp(arg, "--disable=")) {
1159                         enable_service(arg + 10, 0);
1160                         continue;
1161                 }
1162                 if (!prefixcmp(arg, "--allow-override=")) {
1163                         make_service_overridable(arg + 17, 1);
1164                         continue;
1165                 }
1166                 if (!prefixcmp(arg, "--forbid-override=")) {
1167                         make_service_overridable(arg + 18, 0);
1168                         continue;
1169                 }
1170                 if (!strcmp(arg, "--")) {
1171                         ok_paths = &argv[i+1];
1172                         break;
1173                 } else if (arg[0] != '-') {
1174                         ok_paths = &argv[i];
1175                         break;
1176                 }
1177
1178                 usage(daemon_usage);
1179         }
1180
1181         if (log_syslog) {
1182                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1183                 set_die_routine(daemon_die);
1184         } else
1185                 /* avoid splitting a message in the middle */
1186                 setvbuf(stderr, NULL, _IOFBF, 4096);
1187
1188         if (inetd_mode && (detach || group_name || user_name))
1189                 die("--detach, --user and --group are incompatible with --inetd");
1190
1191         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1192                 die("--listen= and --port= are incompatible with --inetd");
1193         else if (listen_port == 0)
1194                 listen_port = DEFAULT_GIT_PORT;
1195
1196         if (group_name && !user_name)
1197                 die("--group supplied without --user");
1198
1199         if (user_name)
1200                 cred = prepare_credentials(user_name, group_name);
1201
1202         if (strict_paths && (!ok_paths || !*ok_paths))
1203                 die("option --strict-paths requires a whitelist");
1204
1205         if (base_path && !is_directory(base_path))
1206                 die("base-path '%s' does not exist or is not a directory",
1207                     base_path);
1208
1209         if (inetd_mode) {
1210                 if (!freopen("/dev/null", "w", stderr))
1211                         die_errno("failed to redirect stderr to /dev/null");
1212         }
1213
1214         if (inetd_mode || serve_mode)
1215                 return execute();
1216
1217         if (detach) {
1218                 daemonize();
1219                 loginfo("Ready to rumble");
1220         }
1221         else
1222                 sanitize_stdfds();
1223
1224         if (pid_file)
1225                 store_pid(pid_file);
1226
1227         /* prepare argv for serving-processes */
1228         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1229         cld_argv[0] = argv[0];  /* git-daemon */
1230         cld_argv[1] = "--serve";
1231         for (i = 1; i < argc; ++i)
1232                 cld_argv[i+1] = argv[i];
1233         cld_argv[argc+1] = NULL;
1234
1235         return serve(&listen_addr, listen_port, cred);
1236 }