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 #include <syslog.h>
   9
  10 #ifndef HOST_NAME_MAX
  11 #define HOST_NAME_MAX 256
  12 #endif
  13
  14 #ifndef NI_MAXSERV
  15 #define NI_MAXSERV 32
  16 #endif
  17
  18 #ifdef NO_INITGROUPS
  19 #define initgroups(x, y) (0) /* nothing */
  20 #endif
  21
  22 static int log_syslog;
  23 static int verbose;
  24 static int reuseaddr;
  25
  26 static const char daemon_usage[] =
  27 "git daemon [--verbose] [--syslog] [--export-all]\n"
  28 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  29 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  30 "           [--user-path | --user-path=<path>]\n"
  31 "           [--interpolated-path=<path>]\n"
  32 "           [--reuseaddr] [--detach] [--pid-file=<file>]\n"
  33 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  34 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  35 "                      [--user=<user> [--group=<group>]]\n"
  36 "           [<directory>...]";
  37
  38 /* List of acceptable pathname prefixes */
  39 static char **ok_paths;
  40 static int strict_paths;
  41
  42 /* If this is set, git-daemon-export-ok is not required */
  43 static int export_all_trees;
  44
  45 /* Take all paths relative to this one if non-NULL */
  46 static char *base_path;
  47 static char *interpolated_path;
  48 static int base_path_relaxed;
  49
  50 /* Flag indicating client sent extra args. */
  51 static int saw_extended_args;
  52
  53 /* If defined, ~user notation is allowed and the string is inserted
  54  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  55  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  56  */
  57 static const char *user_path;
  58
  59 /* Timeout, and initial timeout */
  60 static unsigned int timeout;
  61 static unsigned int init_timeout;
  62
  63 static char *hostname;
  64 static char *canon_hostname;
  65 static char *ip_address;
  66 static char *tcp_port;
  67
  68 static void logreport(int priority, const char *err, va_list params)
  69 {
  70         if (log_syslog) {
  71                 char buf[1024];
  72                 vsnprintf(buf, sizeof(buf), err, params);
  73                 syslog(priority, "%s", buf);
  74         } else {
  75                 /*
  76                  * Since stderr is set to linebuffered mode, the
  77                  * logging of different processes will not overlap
  78                  */
  79                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  80                 vfprintf(stderr, err, params);
  81                 fputc('\n', 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(struct sockaddr *addr)
 524 {
 525         static char line[1000];
 526         int pktlen, len, i;
 527
 528         if (addr) {
 529                 char addrbuf[256] = "";
 530                 int port = -1;
 531
 532                 if (addr->sa_family == AF_INET) {
 533                         struct sockaddr_in *sin_addr = (void *) addr;
 534                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 535                         port = ntohs(sin_addr->sin_port);
 536 #ifndef NO_IPV6
 537                 } else if (addr && addr->sa_family == AF_INET6) {
 538                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 539
 540                         char *buf = addrbuf;
 541                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 542                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 543                         strcat(buf, "]");
 544
 545                         port = ntohs(sin6_addr->sin6_port);
 546 #endif
 547                 }
 548                 loginfo("Connection from %s:%d", addrbuf, port);
 549                 setenv("REMOTE_ADDR", addrbuf, 1);
 550         }
 551         else {
 552                 unsetenv("REMOTE_ADDR");
 553         }
 554
 555         alarm(init_timeout ? init_timeout : timeout);
 556         pktlen = packet_read_line(0, line, sizeof(line));
 557         alarm(0);
 558
 559         len = strlen(line);
 560         if (pktlen != len)
 561                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 562                         (int) pktlen - len,
 563                         (int) pktlen - len, line + len + 1);
 564         if (len && line[len-1] == '\n') {
 565                 line[--len] = 0;
 566                 pktlen--;
 567         }
 568
 569         free(hostname);
 570         free(canon_hostname);
 571         free(ip_address);
 572         free(tcp_port);
 573         hostname = canon_hostname = ip_address = tcp_port = NULL;
 574
 575         if (len != pktlen)
 576                 parse_host_arg(line + len + 1, pktlen - len - 1);
 577
 578         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 579                 struct daemon_service *s = &(daemon_service[i]);
 580                 int namelen = strlen(s->name);
 581                 if (!prefixcmp(line, "git-") &&
 582                     !strncmp(s->name, line + 4, namelen) &&
 583                     line[namelen + 4] == ' ') {
 584                         /*
 585                          * Note: The directory here is probably context sensitive,
 586                          * and might depend on the actual service being performed.
 587                          */
 588                         return run_service(line + namelen + 5, s);
 589                 }
 590         }
 591
 592         logerror("Protocol error: '%s'", line);
 593         return -1;
 594 }
 595
 596 static int addrcmp(const struct sockaddr_storage *s1,
 597     const struct sockaddr_storage *s2)
 598 {
 599         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 600         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 601
 602         if (sa1->sa_family != sa2->sa_family)
 603                 return sa1->sa_family - sa2->sa_family;
 604         if (sa1->sa_family == AF_INET)
 605                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 606                     &((struct sockaddr_in *)s2)->sin_addr,
 607                     sizeof(struct in_addr));
 608 #ifndef NO_IPV6
 609         if (sa1->sa_family == AF_INET6)
 610                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 611                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 612                     sizeof(struct in6_addr));
 613 #endif
 614         return 0;
 615 }
 616
 617 static int max_connections = 32;
 618
 619 static unsigned int live_children;
 620
 621 static struct child {
 622         struct child *next;
 623         pid_t pid;
 624         struct sockaddr_storage address;
 625 } *firstborn;
 626
 627 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 628 {
 629         struct child *newborn, **cradle;
 630
 631         newborn = xcalloc(1, sizeof(*newborn));
 632         live_children++;
 633         newborn->pid = pid;
 634         memcpy(&newborn->address, addr, addrlen);
 635         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 636                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 637                         break;
 638         newborn->next = *cradle;
 639         *cradle = newborn;
 640 }
 641
 642 static void remove_child(pid_t pid)
 643 {
 644         struct child **cradle, *blanket;
 645
 646         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 647                 if (blanket->pid == pid) {
 648                         *cradle = blanket->next;
 649                         live_children--;
 650                         free(blanket);
 651                         break;
 652                 }
 653 }
 654
 655 /*
 656  * This gets called if the number of connections grows
 657  * past "max_connections".
 658  *
 659  * We kill the newest connection from a duplicate IP.
 660  */
 661 static void kill_some_child(void)
 662 {
 663         const struct child *blanket, *next;
 664
 665         if (!(blanket = firstborn))
 666                 return;
 667
 668         for (; (next = blanket->next); blanket = next)
 669                 if (!addrcmp(&blanket->address, &next->address)) {
 670                         kill(blanket->pid, SIGTERM);
 671                         break;
 672                 }
 673 }
 674
 675 static void check_dead_children(void)
 676 {
 677         int status;
 678         pid_t pid;
 679
 680         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 681                 const char *dead = "";
 682                 remove_child(pid);
 683                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 684                         dead = " (with error)";
 685                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 686         }
 687 }
 688
 689 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 690 {
 691         pid_t pid;
 692
 693         if (max_connections && live_children >= max_connections) {
 694                 kill_some_child();
 695                 sleep(1);  /* give it some time to die */
 696                 check_dead_children();
 697                 if (live_children >= max_connections) {
 698                         close(incoming);
 699                         logerror("Too many children, dropping connection");
 700                         return;
 701                 }
 702         }
 703
 704         if ((pid = fork())) {
 705                 close(incoming);
 706                 if (pid < 0) {
 707                         logerror("Couldn't fork %s", strerror(errno));
 708                         return;
 709                 }
 710
 711                 add_child(pid, addr, addrlen);
 712                 return;
 713         }
 714
 715         dup2(incoming, 0);
 716         dup2(incoming, 1);
 717         close(incoming);
 718
 719         exit(execute(addr));
 720 }
 721
 722 static void child_handler(int signo)
 723 {
 724         /*
 725          * Otherwise empty handler because systemcalls will get interrupted
 726          * upon signal receipt
 727          * SysV needs the handler to be rearmed
 728          */
 729         signal(SIGCHLD, child_handler);
 730 }
 731
 732 static int set_reuse_addr(int sockfd)
 733 {
 734         int on = 1;
 735
 736         if (!reuseaddr)
 737                 return 0;
 738         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 739                           &on, sizeof(on));
 740 }
 741
 742 struct socketlist {
 743         int *list;
 744         size_t nr;
 745         size_t alloc;
 746 };
 747
 748 #ifndef NO_IPV6
 749
 750 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 751 {
 752         int socknum = 0;
 753         int maxfd = -1;
 754         char pbuf[NI_MAXSERV];
 755         struct addrinfo hints, *ai0, *ai;
 756         int gai;
 757         long flags;
 758
 759         sprintf(pbuf, "%d", listen_port);
 760         memset(&hints, 0, sizeof(hints));
 761         hints.ai_family = AF_UNSPEC;
 762         hints.ai_socktype = SOCK_STREAM;
 763         hints.ai_protocol = IPPROTO_TCP;
 764         hints.ai_flags = AI_PASSIVE;
 765
 766         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 767         if (gai) {
 768                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 769                 return 0;
 770         }
 771
 772         for (ai = ai0; ai; ai = ai->ai_next) {
 773                 int sockfd;
 774
 775                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 776                 if (sockfd < 0)
 777                         continue;
 778                 if (sockfd >= FD_SETSIZE) {
 779                         logerror("Socket descriptor too large");
 780                         close(sockfd);
 781                         continue;
 782                 }
 783
 784 #ifdef IPV6_V6ONLY
 785                 if (ai->ai_family == AF_INET6) {
 786                         int on = 1;
 787                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 788                                    &on, sizeof(on));
 789                         /* Note: error is not fatal */
 790                 }
 791 #endif
 792
 793                 if (set_reuse_addr(sockfd)) {
 794                         close(sockfd);
 795                         continue;
 796                 }
 797
 798                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 799                         close(sockfd);
 800                         continue;       /* not fatal */
 801                 }
 802                 if (listen(sockfd, 5) < 0) {
 803                         close(sockfd);
 804                         continue;       /* not fatal */
 805                 }
 806
 807                 flags = fcntl(sockfd, F_GETFD, 0);
 808                 if (flags >= 0)
 809                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 810
 811                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 812                 socklist->list[socklist->nr++] = sockfd;
 813                 socknum++;
 814
 815                 if (maxfd < sockfd)
 816                         maxfd = sockfd;
 817         }
 818
 819         freeaddrinfo(ai0);
 820
 821         return socknum;
 822 }
 823
 824 #else /* NO_IPV6 */
 825
 826 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 827 {
 828         struct sockaddr_in sin;
 829         int sockfd;
 830         long flags;
 831
 832         memset(&sin, 0, sizeof sin);
 833         sin.sin_family = AF_INET;
 834         sin.sin_port = htons(listen_port);
 835
 836         if (listen_addr) {
 837                 /* Well, host better be an IP address here. */
 838                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 839                         return 0;
 840         } else {
 841                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 842         }
 843
 844         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 845         if (sockfd < 0)
 846                 return 0;
 847
 848         if (set_reuse_addr(sockfd)) {
 849                 close(sockfd);
 850                 return 0;
 851         }
 852
 853         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 854                 close(sockfd);
 855                 return 0;
 856         }
 857
 858         if (listen(sockfd, 5) < 0) {
 859                 close(sockfd);
 860                 return 0;
 861         }
 862
 863         flags = fcntl(sockfd, F_GETFD, 0);
 864         if (flags >= 0)
 865                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 866
 867         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 868         socklist->list[socklist->nr++] = sockfd;
 869         return 1;
 870 }
 871
 872 #endif
 873
 874 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 875 {
 876         if (!listen_addr->nr)
 877                 setup_named_sock(NULL, listen_port, socklist);
 878         else {
 879                 int i, socknum;
 880                 for (i = 0; i < listen_addr->nr; i++) {
 881                         socknum = setup_named_sock(listen_addr->items[i].string,
 882                                                    listen_port, socklist);
 883
 884                         if (socknum == 0)
 885                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 886                                          listen_addr->items[i].string, listen_port);
 887                 }
 888         }
 889 }
 890
 891 static int service_loop(struct socketlist *socklist)
 892 {
 893         struct pollfd *pfd;
 894         int i;
 895
 896         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 897
 898         for (i = 0; i < socklist->nr; i++) {
 899                 pfd[i].fd = socklist->list[i];
 900                 pfd[i].events = POLLIN;
 901         }
 902
 903         signal(SIGCHLD, child_handler);
 904
 905         for (;;) {
 906                 int i;
 907
 908                 check_dead_children();
 909
 910                 if (poll(pfd, socklist->nr, -1) < 0) {
 911                         if (errno != EINTR) {
 912                                 logerror("Poll failed, resuming: %s",
 913                                       strerror(errno));
 914                                 sleep(1);
 915                         }
 916                         continue;
 917                 }
 918
 919                 for (i = 0; i < socklist->nr; i++) {
 920                         if (pfd[i].revents & POLLIN) {
 921                                 struct sockaddr_storage ss;
 922                                 unsigned int sslen = sizeof(ss);
 923                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 924                                 if (incoming < 0) {
 925                                         switch (errno) {
 926                                         case EAGAIN:
 927                                         case EINTR:
 928                                         case ECONNABORTED:
 929                                                 continue;
 930                                         default:
 931                                                 die_errno("accept returned");
 932                                         }
 933                                 }
 934                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 935                         }
 936                 }
 937         }
 938 }
 939
 940 /* if any standard file descriptor is missing open it to /dev/null */
 941 static void sanitize_stdfds(void)
 942 {
 943         int fd = open("/dev/null", O_RDWR, 0);
 944         while (fd != -1 && fd < 2)
 945                 fd = dup(fd);
 946         if (fd == -1)
 947                 die_errno("open /dev/null or dup failed");
 948         if (fd > 2)
 949                 close(fd);
 950 }
 951
 952 static void daemonize(void)
 953 {
 954         switch (fork()) {
 955                 case 0:
 956                         break;
 957                 case -1:
 958                         die_errno("fork failed");
 959                 default:
 960                         exit(0);
 961         }
 962         if (setsid() == -1)
 963                 die_errno("setsid failed");
 964         close(0);
 965         close(1);
 966         close(2);
 967         sanitize_stdfds();
 968 }
 969
 970 static void store_pid(const char *path)
 971 {
 972         FILE *f = fopen(path, "w");
 973         if (!f)
 974                 die_errno("cannot open pid file '%s'", path);
 975         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 976                 die_errno("failed to write pid file '%s'", path);
 977 }
 978
 979 static int serve(struct string_list *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 980 {
 981         struct socketlist socklist = { NULL, 0, 0 };
 982
 983         socksetup(listen_addr, listen_port, &socklist);
 984         if (socklist.nr == 0)
 985                 die("unable to allocate any listen sockets on port %u",
 986                     listen_port);
 987
 988         if (pass && gid &&
 989             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 990              setuid(pass->pw_uid)))
 991                 die("cannot drop privileges");
 992
 993         return service_loop(&socklist);
 994 }
 995
 996 int main(int argc, char **argv)
 997 {
 998         int listen_port = 0;
 999         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1000         int inetd_mode = 0;
1001         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1002         int detach = 0;
1003         struct passwd *pass = NULL;
1004         struct group *group;
1005         gid_t gid = 0;
1006         int i;
1007
1008         git_extract_argv0_path(argv[0]);
1009
1010         for (i = 1; i < argc; i++) {
1011                 char *arg = argv[i];
1012
1013                 if (!prefixcmp(arg, "--listen=")) {
1014                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1015                         continue;
1016                 }
1017                 if (!prefixcmp(arg, "--port=")) {
1018                         char *end;
1019                         unsigned long n;
1020                         n = strtoul(arg+7, &end, 0);
1021                         if (arg[7] && !*end) {
1022                                 listen_port = n;
1023                                 continue;
1024                         }
1025                 }
1026                 if (!strcmp(arg, "--inetd")) {
1027                         inetd_mode = 1;
1028                         log_syslog = 1;
1029                         continue;
1030                 }
1031                 if (!strcmp(arg, "--verbose")) {
1032                         verbose = 1;
1033                         continue;
1034                 }
1035                 if (!strcmp(arg, "--syslog")) {
1036                         log_syslog = 1;
1037                         continue;
1038                 }
1039                 if (!strcmp(arg, "--export-all")) {
1040                         export_all_trees = 1;
1041                         continue;
1042                 }
1043                 if (!prefixcmp(arg, "--timeout=")) {
1044                         timeout = atoi(arg+10);
1045                         continue;
1046                 }
1047                 if (!prefixcmp(arg, "--init-timeout=")) {
1048                         init_timeout = atoi(arg+15);
1049                         continue;
1050                 }
1051                 if (!prefixcmp(arg, "--max-connections=")) {
1052                         max_connections = atoi(arg+18);
1053                         if (max_connections < 0)
1054                                 max_connections = 0;            /* unlimited */
1055                         continue;
1056                 }
1057                 if (!strcmp(arg, "--strict-paths")) {
1058                         strict_paths = 1;
1059                         continue;
1060                 }
1061                 if (!prefixcmp(arg, "--base-path=")) {
1062                         base_path = arg+12;
1063                         continue;
1064                 }
1065                 if (!strcmp(arg, "--base-path-relaxed")) {
1066                         base_path_relaxed = 1;
1067                         continue;
1068                 }
1069                 if (!prefixcmp(arg, "--interpolated-path=")) {
1070                         interpolated_path = arg+20;
1071                         continue;
1072                 }
1073                 if (!strcmp(arg, "--reuseaddr")) {
1074                         reuseaddr = 1;
1075                         continue;
1076                 }
1077                 if (!strcmp(arg, "--user-path")) {
1078                         user_path = "";
1079                         continue;
1080                 }
1081                 if (!prefixcmp(arg, "--user-path=")) {
1082                         user_path = arg + 12;
1083                         continue;
1084                 }
1085                 if (!prefixcmp(arg, "--pid-file=")) {
1086                         pid_file = arg + 11;
1087                         continue;
1088                 }
1089                 if (!strcmp(arg, "--detach")) {
1090                         detach = 1;
1091                         log_syslog = 1;
1092                         continue;
1093                 }
1094                 if (!prefixcmp(arg, "--user=")) {
1095                         user_name = arg + 7;
1096                         continue;
1097                 }
1098                 if (!prefixcmp(arg, "--group=")) {
1099                         group_name = arg + 8;
1100                         continue;
1101                 }
1102                 if (!prefixcmp(arg, "--enable=")) {
1103                         enable_service(arg + 9, 1);
1104                         continue;
1105                 }
1106                 if (!prefixcmp(arg, "--disable=")) {
1107                         enable_service(arg + 10, 0);
1108                         continue;
1109                 }
1110                 if (!prefixcmp(arg, "--allow-override=")) {
1111                         make_service_overridable(arg + 17, 1);
1112                         continue;
1113                 }
1114                 if (!prefixcmp(arg, "--forbid-override=")) {
1115                         make_service_overridable(arg + 18, 0);
1116                         continue;
1117                 }
1118                 if (!strcmp(arg, "--")) {
1119                         ok_paths = &argv[i+1];
1120                         break;
1121                 } else if (arg[0] != '-') {
1122                         ok_paths = &argv[i];
1123                         break;
1124                 }
1125
1126                 usage(daemon_usage);
1127         }
1128
1129         if (log_syslog) {
1130                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1131                 set_die_routine(daemon_die);
1132         } else
1133                 /* avoid splitting a message in the middle */
1134                 setvbuf(stderr, NULL, _IOLBF, 0);
1135
1136         if (inetd_mode && (group_name || user_name))
1137                 die("--user and --group are incompatible with --inetd");
1138
1139         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1140                 die("--listen= and --port= are incompatible with --inetd");
1141         else if (listen_port == 0)
1142                 listen_port = DEFAULT_GIT_PORT;
1143
1144         if (group_name && !user_name)
1145                 die("--group supplied without --user");
1146
1147         if (user_name) {
1148                 pass = getpwnam(user_name);
1149                 if (!pass)
1150                         die("user not found - %s", user_name);
1151
1152                 if (!group_name)
1153                         gid = pass->pw_gid;
1154                 else {
1155                         group = getgrnam(group_name);
1156                         if (!group)
1157                                 die("group not found - %s", group_name);
1158
1159                         gid = group->gr_gid;
1160                 }
1161         }
1162
1163         if (strict_paths && (!ok_paths || !*ok_paths))
1164                 die("option --strict-paths requires a whitelist");
1165
1166         if (base_path && !is_directory(base_path))
1167                 die("base-path '%s' does not exist or is not a directory",
1168                     base_path);
1169
1170         if (inetd_mode) {
1171                 struct sockaddr_storage ss;
1172                 struct sockaddr *peer = (struct sockaddr *)&ss;
1173                 socklen_t slen = sizeof(ss);
1174
1175                 if (!freopen("/dev/null", "w", stderr))
1176                         die_errno("failed to redirect stderr to /dev/null");
1177
1178                 if (getpeername(0, peer, &slen))
1179                         peer = NULL;
1180
1181                 return execute(peer);
1182         }
1183
1184         if (detach) {
1185                 daemonize();
1186                 loginfo("Ready to rumble");
1187         }
1188         else
1189                 sanitize_stdfds();
1190
1191         if (pid_file)
1192                 store_pid(pid_file);
1193
1194         return serve(&listen_addr, listen_port, pass, gid);
1195 }