daemon.c

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