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 #ifdef NO_INITGROUPS
  13 #define initgroups(x, y) (0) /* nothing */
  14 #endif
  15
  16 static int log_syslog;
  17 static int verbose;
  18 static int reuseaddr;
  19 static int informative_errors;
  20
  21 static const char daemon_usage[] =
  22 "git daemon [--verbose] [--syslog] [--export-all]\n"
  23 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  24 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  25 "           [--user-path | --user-path=<path>]\n"
  26 "           [--interpolated-path=<path>]\n"
  27 "           [--reuseaddr] [--pid-file=<file>]\n"
  28 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  29 "           [--access-hook=<path>]\n"
  30 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  31 "                      [--detach] [--user=<user> [--group=<group>]]\n"
  32 "           [<directory>...]";
  33
  34 /* List of acceptable pathname prefixes */
  35 static char **ok_paths;
  36 static int strict_paths;
  37
  38 /* If this is set, git-daemon-export-ok is not required */
  39 static int export_all_trees;
  40
  41 /* Take all paths relative to this one if non-NULL */
  42 static const char *base_path;
  43 static const char *interpolated_path;
  44 static int base_path_relaxed;
  45
  46 /* Flag indicating client sent extra args. */
  47 static int saw_extended_args;
  48
  49 /* If defined, ~user notation is allowed and the string is inserted
  50  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  51  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  52  */
  53 static const char *user_path;
  54
  55 /* Timeout, and initial timeout */
  56 static unsigned int timeout;
  57 static unsigned int init_timeout;
  58
  59 static char *hostname;
  60 static char *canon_hostname;
  61 static char *ip_address;
  62 static char *tcp_port;
  63
  64 static void logreport(int priority, const char *err, va_list params)
  65 {
  66         if (log_syslog) {
  67                 char buf[1024];
  68                 vsnprintf(buf, sizeof(buf), err, params);
  69                 syslog(priority, "%s", buf);
  70         } else {
  71                 /*
  72                  * Since stderr is set to buffered mode, the
  73                  * logging of different processes will not overlap
  74                  * unless they overflow the (rather big) buffers.
  75                  */
  76                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  77                 vfprintf(stderr, err, params);
  78                 fputc('\n', stderr);
  79                 fflush(stderr);
  80         }
  81 }
  82
  83 __attribute__((format (printf, 1, 2)))
  84 static void logerror(const char *err, ...)
  85 {
  86         va_list params;
  87         va_start(params, err);
  88         logreport(LOG_ERR, err, params);
  89         va_end(params);
  90 }
  91
  92 __attribute__((format (printf, 1, 2)))
  93 static void loginfo(const char *err, ...)
  94 {
  95         va_list params;
  96         if (!verbose)
  97                 return;
  98         va_start(params, err);
  99         logreport(LOG_INFO, err, params);
 100         va_end(params);
 101 }
 102
 103 static void NORETURN daemon_die(const char *err, va_list params)
 104 {
 105         logreport(LOG_ERR, err, params);
 106         exit(1);
 107 }
 108
 109 static const char *path_ok(const char *directory)
 110 {
 111         static char rpath[PATH_MAX];
 112         static char interp_path[PATH_MAX];
 113         const char *path;
 114         const char *dir;
 115
 116         dir = directory;
 117
 118         if (daemon_avoid_alias(dir)) {
 119                 logerror("'%s': aliased", dir);
 120                 return NULL;
 121         }
 122
 123         if (*dir == '~') {
 124                 if (!user_path) {
 125                         logerror("'%s': User-path not allowed", dir);
 126                         return NULL;
 127                 }
 128                 if (*user_path) {
 129                         /* Got either "~alice" or "~alice/foo";
 130                          * rewrite them to "~alice/%s" or
 131                          * "~alice/%s/foo".
 132                          */
 133                         int namlen, restlen = strlen(dir);
 134                         const char *slash = strchr(dir, '/');
 135                         if (!slash)
 136                                 slash = dir + restlen;
 137                         namlen = slash - dir;
 138                         restlen -= namlen;
 139                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 140                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 141                                  namlen, dir, user_path, restlen, slash);
 142                         dir = rpath;
 143                 }
 144         }
 145         else if (interpolated_path && saw_extended_args) {
 146                 struct strbuf expanded_path = STRBUF_INIT;
 147                 struct strbuf_expand_dict_entry dict[6];
 148
 149                 dict[0].placeholder = "H"; dict[0].value = hostname;
 150                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 151                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
 152                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
 153                 dict[4].placeholder = "D"; dict[4].value = directory;
 154                 dict[5].placeholder = NULL; dict[5].value = NULL;
 155                 if (*dir != '/') {
 156                         /* Allow only absolute */
 157                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 158                         return NULL;
 159                 }
 160
 161                 strbuf_expand(&expanded_path, interpolated_path,
 162                                 strbuf_expand_dict_cb, &dict);
 163                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 164                 strbuf_release(&expanded_path);
 165                 loginfo("Interpolated dir '%s'", interp_path);
 166
 167                 dir = interp_path;
 168         }
 169         else if (base_path) {
 170                 if (*dir != '/') {
 171                         /* Allow only absolute */
 172                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 173                         return NULL;
 174                 }
 175                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 176                 dir = rpath;
 177         }
 178
 179         path = enter_repo(dir, strict_paths);
 180         if (!path && base_path && base_path_relaxed) {
 181                 /*
 182                  * if we fail and base_path_relaxed is enabled, try without
 183                  * prefixing the base path
 184                  */
 185                 dir = directory;
 186                 path = enter_repo(dir, strict_paths);
 187         }
 188
 189         if (!path) {
 190                 logerror("'%s' does not appear to be a git repository", dir);
 191                 return NULL;
 192         }
 193
 194         if ( ok_paths && *ok_paths ) {
 195                 char **pp;
 196                 int pathlen = strlen(path);
 197
 198                 /* The validation is done on the paths after enter_repo
 199                  * appends optional {.git,.git/.git} and friends, but
 200                  * it does not use getcwd().  So if your /pub is
 201                  * a symlink to /mnt/pub, you can whitelist /pub and
 202                  * do not have to say /mnt/pub.
 203                  * Do not say /pub/.
 204                  */
 205                 for ( pp = ok_paths ; *pp ; pp++ ) {
 206                         int len = strlen(*pp);
 207                         if (len <= pathlen &&
 208                             !memcmp(*pp, path, len) &&
 209                             (path[len] == '\0' ||
 210                              (!strict_paths && path[len] == '/')))
 211                                 return path;
 212                 }
 213         }
 214         else {
 215                 /* be backwards compatible */
 216                 if (!strict_paths)
 217                         return path;
 218         }
 219
 220         logerror("'%s': not in whitelist", path);
 221         return NULL;            /* Fallthrough. Deny by default */
 222 }
 223
 224 typedef int (*daemon_service_fn)(void);
 225 struct daemon_service {
 226         const char *name;
 227         const char *config_name;
 228         daemon_service_fn fn;
 229         int enabled;
 230         int overridable;
 231 };
 232
 233 static struct daemon_service *service_looking_at;
 234 static int service_enabled;
 235
 236 static int git_daemon_config(const char *var, const char *value, void *cb)
 237 {
 238         const char *service;
 239
 240         if (skip_prefix(var, "daemon.", &service) &&
 241             !strcmp(service, 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 daemon_error(const char *dir, const char *msg)
 251 {
 252         if (!informative_errors)
 253                 msg = "access denied or repository not exported";
 254         packet_write(1, "ERR %s: %s", msg, dir);
 255         return -1;
 256 }
 257
 258 static const char *access_hook;
 259
 260 static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 261 {
 262         struct child_process child;
 263         struct strbuf buf = STRBUF_INIT;
 264         const char *argv[8];
 265         const char **arg = argv;
 266         char *eol;
 267         int seen_errors = 0;
 268
 269 #define STRARG(x) ((x) ? (x) : "")
 270         *arg++ = access_hook;
 271         *arg++ = service->name;
 272         *arg++ = path;
 273         *arg++ = STRARG(hostname);
 274         *arg++ = STRARG(canon_hostname);
 275         *arg++ = STRARG(ip_address);
 276         *arg++ = STRARG(tcp_port);
 277         *arg = NULL;
 278 #undef STRARG
 279
 280         memset(&child, 0, sizeof(child));
 281         child.use_shell = 1;
 282         child.argv = argv;
 283         child.no_stdin = 1;
 284         child.no_stderr = 1;
 285         child.out = -1;
 286         if (start_command(&child)) {
 287                 logerror("daemon access hook '%s' failed to start",
 288                          access_hook);
 289                 goto error_return;
 290         }
 291         if (strbuf_read(&buf, child.out, 0) < 0) {
 292                 logerror("failed to read from pipe to daemon access hook '%s'",
 293                          access_hook);
 294                 strbuf_reset(&buf);
 295                 seen_errors = 1;
 296         }
 297         if (close(child.out) < 0) {
 298                 logerror("failed to close pipe to daemon access hook '%s'",
 299                          access_hook);
 300                 seen_errors = 1;
 301         }
 302         if (finish_command(&child))
 303                 seen_errors = 1;
 304
 305         if (!seen_errors) {
 306                 strbuf_release(&buf);
 307                 return 0;
 308         }
 309
 310 error_return:
 311         strbuf_ltrim(&buf);
 312         if (!buf.len)
 313                 strbuf_addstr(&buf, "service rejected");
 314         eol = strchr(buf.buf, '\n');
 315         if (eol)
 316                 *eol = '\0';
 317         errno = EACCES;
 318         daemon_error(dir, buf.buf);
 319         strbuf_release(&buf);
 320         return -1;
 321 }
 322
 323 static int run_service(const char *dir, struct daemon_service *service)
 324 {
 325         const char *path;
 326         int enabled = service->enabled;
 327
 328         loginfo("Request %s for '%s'", service->name, dir);
 329
 330         if (!enabled && !service->overridable) {
 331                 logerror("'%s': service not enabled.", service->name);
 332                 errno = EACCES;
 333                 return daemon_error(dir, "service not enabled");
 334         }
 335
 336         if (!(path = path_ok(dir)))
 337                 return daemon_error(dir, "no such repository");
 338
 339         /*
 340          * Security on the cheap.
 341          *
 342          * We want a readable HEAD, usable "objects" directory, and
 343          * a "git-daemon-export-ok" flag that says that the other side
 344          * is ok with us doing this.
 345          *
 346          * path_ok() uses enter_repo() and does whitelist checking.
 347          * We only need to make sure the repository is exported.
 348          */
 349
 350         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 351                 logerror("'%s': repository not exported.", path);
 352                 errno = EACCES;
 353                 return daemon_error(dir, "repository not exported");
 354         }
 355
 356         if (service->overridable) {
 357                 service_looking_at = service;
 358                 service_enabled = -1;
 359                 git_config(git_daemon_config, NULL);
 360                 if (0 <= service_enabled)
 361                         enabled = service_enabled;
 362         }
 363         if (!enabled) {
 364                 logerror("'%s': service not enabled for '%s'",
 365                          service->name, path);
 366                 errno = EACCES;
 367                 return daemon_error(dir, "service not enabled");
 368         }
 369
 370         /*
 371          * Optionally, a hook can choose to deny access to the
 372          * repository depending on the phase of the moon.
 373          */
 374         if (access_hook && run_access_hook(service, dir, path))
 375                 return -1;
 376
 377         /*
 378          * We'll ignore SIGTERM from now on, we have a
 379          * good client.
 380          */
 381         signal(SIGTERM, SIG_IGN);
 382
 383         return service->fn();
 384 }
 385
 386 static void copy_to_log(int fd)
 387 {
 388         struct strbuf line = STRBUF_INIT;
 389         FILE *fp;
 390
 391         fp = fdopen(fd, "r");
 392         if (fp == NULL) {
 393                 logerror("fdopen of error channel failed");
 394                 close(fd);
 395                 return;
 396         }
 397
 398         while (strbuf_getline(&line, fp, '\n') != EOF) {
 399                 logerror("%s", line.buf);
 400                 strbuf_setlen(&line, 0);
 401         }
 402
 403         strbuf_release(&line);
 404         fclose(fp);
 405 }
 406
 407 static int run_service_command(const char **argv)
 408 {
 409         struct child_process cld;
 410
 411         memset(&cld, 0, sizeof(cld));
 412         cld.argv = argv;
 413         cld.git_cmd = 1;
 414         cld.err = -1;
 415         if (start_command(&cld))
 416                 return -1;
 417
 418         close(0);
 419         close(1);
 420
 421         copy_to_log(cld.err);
 422
 423         return finish_command(&cld);
 424 }
 425
 426 static int upload_pack(void)
 427 {
 428         /* Timeout as string */
 429         char timeout_buf[64];
 430         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 431
 432         argv[2] = timeout_buf;
 433
 434         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 435         return run_service_command(argv);
 436 }
 437
 438 static int upload_archive(void)
 439 {
 440         static const char *argv[] = { "upload-archive", ".", NULL };
 441         return run_service_command(argv);
 442 }
 443
 444 static int receive_pack(void)
 445 {
 446         static const char *argv[] = { "receive-pack", ".", NULL };
 447         return run_service_command(argv);
 448 }
 449
 450 static struct daemon_service daemon_service[] = {
 451         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 452         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 453         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 454 };
 455
 456 static void enable_service(const char *name, int ena)
 457 {
 458         int i;
 459         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 460                 if (!strcmp(daemon_service[i].name, name)) {
 461                         daemon_service[i].enabled = ena;
 462                         return;
 463                 }
 464         }
 465         die("No such service %s", name);
 466 }
 467
 468 static void make_service_overridable(const char *name, int ena)
 469 {
 470         int i;
 471         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 472                 if (!strcmp(daemon_service[i].name, name)) {
 473                         daemon_service[i].overridable = ena;
 474                         return;
 475                 }
 476         }
 477         die("No such service %s", name);
 478 }
 479
 480 static void parse_host_and_port(char *hostport, char **host,
 481         char **port)
 482 {
 483         if (*hostport == '[') {
 484                 char *end;
 485
 486                 end = strchr(hostport, ']');
 487                 if (!end)
 488                         die("Invalid request ('[' without ']')");
 489                 *end = '\0';
 490                 *host = hostport + 1;
 491                 if (!end[1])
 492                         *port = NULL;
 493                 else if (end[1] == ':')
 494                         *port = end + 2;
 495                 else
 496                         die("Garbage after end of host part");
 497         } else {
 498                 *host = hostport;
 499                 *port = strrchr(hostport, ':');
 500                 if (*port) {
 501                         **port = '\0';
 502                         ++*port;
 503                 }
 504         }
 505 }
 506
 507 /*
 508  * Read the host as supplied by the client connection.
 509  */
 510 static void parse_host_arg(char *extra_args, int buflen)
 511 {
 512         char *val;
 513         int vallen;
 514         char *end = extra_args + buflen;
 515
 516         if (extra_args < end && *extra_args) {
 517                 saw_extended_args = 1;
 518                 if (strncasecmp("host=", extra_args, 5) == 0) {
 519                         val = extra_args + 5;
 520                         vallen = strlen(val) + 1;
 521                         if (*val) {
 522                                 /* Split <host>:<port> at colon. */
 523                                 char *host;
 524                                 char *port;
 525                                 parse_host_and_port(val, &host, &port);
 526                                 if (port) {
 527                                         free(tcp_port);
 528                                         tcp_port = xstrdup(port);
 529                                 }
 530                                 free(hostname);
 531                                 hostname = xstrdup_tolower(host);
 532                         }
 533
 534                         /* On to the next one */
 535                         extra_args = val + vallen;
 536                 }
 537                 if (extra_args < end && *extra_args)
 538                         die("Invalid request");
 539         }
 540
 541         /*
 542          * Locate canonical hostname and its IP address.
 543          */
 544         if (hostname) {
 545 #ifndef NO_IPV6
 546                 struct addrinfo hints;
 547                 struct addrinfo *ai;
 548                 int gai;
 549                 static char addrbuf[HOST_NAME_MAX + 1];
 550
 551                 memset(&hints, 0, sizeof(hints));
 552                 hints.ai_flags = AI_CANONNAME;
 553
 554                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 555                 if (!gai) {
 556                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 557
 558                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 559                                   addrbuf, sizeof(addrbuf));
 560                         free(ip_address);
 561                         ip_address = xstrdup(addrbuf);
 562
 563                         free(canon_hostname);
 564                         canon_hostname = xstrdup(ai->ai_canonname ?
 565                                                  ai->ai_canonname : ip_address);
 566
 567                         freeaddrinfo(ai);
 568                 }
 569 #else
 570                 struct hostent *hent;
 571                 struct sockaddr_in sa;
 572                 char **ap;
 573                 static char addrbuf[HOST_NAME_MAX + 1];
 574
 575                 hent = gethostbyname(hostname);
 576                 if (hent) {
 577                         ap = hent->h_addr_list;
 578                         memset(&sa, 0, sizeof sa);
 579                         sa.sin_family = hent->h_addrtype;
 580                         sa.sin_port = htons(0);
 581                         memcpy(&sa.sin_addr, *ap, hent->h_length);
 582
 583                         inet_ntop(hent->h_addrtype, &sa.sin_addr,
 584                                   addrbuf, sizeof(addrbuf));
 585
 586                         free(canon_hostname);
 587                         canon_hostname = xstrdup(hent->h_name);
 588                         free(ip_address);
 589                         ip_address = xstrdup(addrbuf);
 590                 }
 591 #endif
 592         }
 593 }
 594
 595
 596 static int execute(void)
 597 {
 598         char *line = packet_buffer;
 599         int pktlen, len, i;
 600         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 601
 602         if (addr)
 603                 loginfo("Connection from %s:%s", addr, port);
 604
 605         alarm(init_timeout ? init_timeout : timeout);
 606         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 607         alarm(0);
 608
 609         len = strlen(line);
 610         if (pktlen != len)
 611                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 612                         (int) pktlen - len,
 613                         (int) pktlen - len, line + len + 1);
 614         if (len && line[len-1] == '\n') {
 615                 line[--len] = 0;
 616                 pktlen--;
 617         }
 618
 619         free(hostname);
 620         free(canon_hostname);
 621         free(ip_address);
 622         free(tcp_port);
 623         hostname = canon_hostname = ip_address = tcp_port = NULL;
 624
 625         if (len != pktlen)
 626                 parse_host_arg(line + len + 1, pktlen - len - 1);
 627
 628         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 629                 struct daemon_service *s = &(daemon_service[i]);
 630                 const char *arg;
 631
 632                 if (skip_prefix(line, "git-", &arg) &&
 633                     skip_prefix(arg, s->name, &arg) &&
 634                     *arg++ == ' ') {
 635                         /*
 636                          * Note: The directory here is probably context sensitive,
 637                          * and might depend on the actual service being performed.
 638                          */
 639                         return run_service(arg, s);
 640                 }
 641         }
 642
 643         logerror("Protocol error: '%s'", line);
 644         return -1;
 645 }
 646
 647 static int addrcmp(const struct sockaddr_storage *s1,
 648     const struct sockaddr_storage *s2)
 649 {
 650         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 651         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 652
 653         if (sa1->sa_family != sa2->sa_family)
 654                 return sa1->sa_family - sa2->sa_family;
 655         if (sa1->sa_family == AF_INET)
 656                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 657                     &((struct sockaddr_in *)s2)->sin_addr,
 658                     sizeof(struct in_addr));
 659 #ifndef NO_IPV6
 660         if (sa1->sa_family == AF_INET6)
 661                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 662                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 663                     sizeof(struct in6_addr));
 664 #endif
 665         return 0;
 666 }
 667
 668 static int max_connections = 32;
 669
 670 static unsigned int live_children;
 671
 672 static struct child {
 673         struct child *next;
 674         struct child_process cld;
 675         struct sockaddr_storage address;
 676 } *firstborn;
 677
 678 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 679 {
 680         struct child *newborn, **cradle;
 681
 682         newborn = xcalloc(1, sizeof(*newborn));
 683         live_children++;
 684         memcpy(&newborn->cld, cld, sizeof(*cld));
 685         memcpy(&newborn->address, addr, addrlen);
 686         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 687                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 688                         break;
 689         newborn->next = *cradle;
 690         *cradle = newborn;
 691 }
 692
 693 /*
 694  * This gets called if the number of connections grows
 695  * past "max_connections".
 696  *
 697  * We kill the newest connection from a duplicate IP.
 698  */
 699 static void kill_some_child(void)
 700 {
 701         const struct child *blanket, *next;
 702
 703         if (!(blanket = firstborn))
 704                 return;
 705
 706         for (; (next = blanket->next); blanket = next)
 707                 if (!addrcmp(&blanket->address, &next->address)) {
 708                         kill(blanket->cld.pid, SIGTERM);
 709                         break;
 710                 }
 711 }
 712
 713 static void check_dead_children(void)
 714 {
 715         int status;
 716         pid_t pid;
 717
 718         struct child **cradle, *blanket;
 719         for (cradle = &firstborn; (blanket = *cradle);)
 720                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 721                         const char *dead = "";
 722                         if (status)
 723                                 dead = " (with error)";
 724                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 725
 726                         /* remove the child */
 727                         *cradle = blanket->next;
 728                         live_children--;
 729                         free(blanket);
 730                 } else
 731                         cradle = &blanket->next;
 732 }
 733
 734 static char **cld_argv;
 735 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 736 {
 737         struct child_process cld = { NULL };
 738         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 739         char *env[] = { addrbuf, portbuf, NULL };
 740
 741         if (max_connections && live_children >= max_connections) {
 742                 kill_some_child();
 743                 sleep(1);  /* give it some time to die */
 744                 check_dead_children();
 745                 if (live_children >= max_connections) {
 746                         close(incoming);
 747                         logerror("Too many children, dropping connection");
 748                         return;
 749                 }
 750         }
 751
 752         if (addr->sa_family == AF_INET) {
 753                 struct sockaddr_in *sin_addr = (void *) addr;
 754                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 755                     sizeof(addrbuf) - 12);
 756                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 757                     ntohs(sin_addr->sin_port));
 758 #ifndef NO_IPV6
 759         } else if (addr->sa_family == AF_INET6) {
 760                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 761
 762                 char *buf = addrbuf + 12;
 763                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 764                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 765                     sizeof(addrbuf) - 13);
 766                 strcat(buf, "]");
 767
 768                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 769                     ntohs(sin6_addr->sin6_port));
 770 #endif
 771         }
 772
 773         cld.env = (const char **)env;
 774         cld.argv = (const char **)cld_argv;
 775         cld.in = incoming;
 776         cld.out = dup(incoming);
 777
 778         if (start_command(&cld))
 779                 logerror("unable to fork");
 780         else
 781                 add_child(&cld, addr, addrlen);
 782 }
 783
 784 static void child_handler(int signo)
 785 {
 786         /*
 787          * Otherwise empty handler because systemcalls will get interrupted
 788          * upon signal receipt
 789          * SysV needs the handler to be rearmed
 790          */
 791         signal(SIGCHLD, child_handler);
 792 }
 793
 794 static int set_reuse_addr(int sockfd)
 795 {
 796         int on = 1;
 797
 798         if (!reuseaddr)
 799                 return 0;
 800         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 801                           &on, sizeof(on));
 802 }
 803
 804 struct socketlist {
 805         int *list;
 806         size_t nr;
 807         size_t alloc;
 808 };
 809
 810 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 811 {
 812 #ifdef NO_IPV6
 813         static char ip[INET_ADDRSTRLEN];
 814 #else
 815         static char ip[INET6_ADDRSTRLEN];
 816 #endif
 817
 818         switch (family) {
 819 #ifndef NO_IPV6
 820         case AF_INET6:
 821                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 822                 break;
 823 #endif
 824         case AF_INET:
 825                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 826                 break;
 827         default:
 828                 strcpy(ip, "<unknown>");
 829         }
 830         return ip;
 831 }
 832
 833 #ifndef NO_IPV6
 834
 835 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 836 {
 837         int socknum = 0;
 838         char pbuf[NI_MAXSERV];
 839         struct addrinfo hints, *ai0, *ai;
 840         int gai;
 841         long flags;
 842
 843         sprintf(pbuf, "%d", listen_port);
 844         memset(&hints, 0, sizeof(hints));
 845         hints.ai_family = AF_UNSPEC;
 846         hints.ai_socktype = SOCK_STREAM;
 847         hints.ai_protocol = IPPROTO_TCP;
 848         hints.ai_flags = AI_PASSIVE;
 849
 850         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 851         if (gai) {
 852                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 853                 return 0;
 854         }
 855
 856         for (ai = ai0; ai; ai = ai->ai_next) {
 857                 int sockfd;
 858
 859                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 860                 if (sockfd < 0)
 861                         continue;
 862                 if (sockfd >= FD_SETSIZE) {
 863                         logerror("Socket descriptor too large");
 864                         close(sockfd);
 865                         continue;
 866                 }
 867
 868 #ifdef IPV6_V6ONLY
 869                 if (ai->ai_family == AF_INET6) {
 870                         int on = 1;
 871                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 872                                    &on, sizeof(on));
 873                         /* Note: error is not fatal */
 874                 }
 875 #endif
 876
 877                 if (set_reuse_addr(sockfd)) {
 878                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 879                         close(sockfd);
 880                         continue;
 881                 }
 882
 883                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 884                         logerror("Could not bind to %s: %s",
 885                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 886                                  strerror(errno));
 887                         close(sockfd);
 888                         continue;       /* not fatal */
 889                 }
 890                 if (listen(sockfd, 5) < 0) {
 891                         logerror("Could not listen to %s: %s",
 892                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 893                                  strerror(errno));
 894                         close(sockfd);
 895                         continue;       /* not fatal */
 896                 }
 897
 898                 flags = fcntl(sockfd, F_GETFD, 0);
 899                 if (flags >= 0)
 900                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 901
 902                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 903                 socklist->list[socklist->nr++] = sockfd;
 904                 socknum++;
 905         }
 906
 907         freeaddrinfo(ai0);
 908
 909         return socknum;
 910 }
 911
 912 #else /* NO_IPV6 */
 913
 914 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 915 {
 916         struct sockaddr_in sin;
 917         int sockfd;
 918         long flags;
 919
 920         memset(&sin, 0, sizeof sin);
 921         sin.sin_family = AF_INET;
 922         sin.sin_port = htons(listen_port);
 923
 924         if (listen_addr) {
 925                 /* Well, host better be an IP address here. */
 926                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 927                         return 0;
 928         } else {
 929                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 930         }
 931
 932         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 933         if (sockfd < 0)
 934                 return 0;
 935
 936         if (set_reuse_addr(sockfd)) {
 937                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 938                 close(sockfd);
 939                 return 0;
 940         }
 941
 942         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 943                 logerror("Could not bind to %s: %s",
 944                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 945                          strerror(errno));
 946                 close(sockfd);
 947                 return 0;
 948         }
 949
 950         if (listen(sockfd, 5) < 0) {
 951                 logerror("Could not listen to %s: %s",
 952                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 953                          strerror(errno));
 954                 close(sockfd);
 955                 return 0;
 956         }
 957
 958         flags = fcntl(sockfd, F_GETFD, 0);
 959         if (flags >= 0)
 960                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 961
 962         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 963         socklist->list[socklist->nr++] = sockfd;
 964         return 1;
 965 }
 966
 967 #endif
 968
 969 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 970 {
 971         if (!listen_addr->nr)
 972                 setup_named_sock(NULL, listen_port, socklist);
 973         else {
 974                 int i, socknum;
 975                 for (i = 0; i < listen_addr->nr; i++) {
 976                         socknum = setup_named_sock(listen_addr->items[i].string,
 977                                                    listen_port, socklist);
 978
 979                         if (socknum == 0)
 980                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 981                                          listen_addr->items[i].string, listen_port);
 982                 }
 983         }
 984 }
 985
 986 static int service_loop(struct socketlist *socklist)
 987 {
 988         struct pollfd *pfd;
 989         int i;
 990
 991         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 992
 993         for (i = 0; i < socklist->nr; i++) {
 994                 pfd[i].fd = socklist->list[i];
 995                 pfd[i].events = POLLIN;
 996         }
 997
 998         signal(SIGCHLD, child_handler);
 999
1000         for (;;) {
1001                 int i;
1002
1003                 check_dead_children();
1004
1005                 if (poll(pfd, socklist->nr, -1) < 0) {
1006                         if (errno != EINTR) {
1007                                 logerror("Poll failed, resuming: %s",
1008                                       strerror(errno));
1009                                 sleep(1);
1010                         }
1011                         continue;
1012                 }
1013
1014                 for (i = 0; i < socklist->nr; i++) {
1015                         if (pfd[i].revents & POLLIN) {
1016                                 union {
1017                                         struct sockaddr sa;
1018                                         struct sockaddr_in sai;
1019 #ifndef NO_IPV6
1020                                         struct sockaddr_in6 sai6;
1021 #endif
1022                                 } ss;
1023                                 socklen_t sslen = sizeof(ss);
1024                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1025                                 if (incoming < 0) {
1026                                         switch (errno) {
1027                                         case EAGAIN:
1028                                         case EINTR:
1029                                         case ECONNABORTED:
1030                                                 continue;
1031                                         default:
1032                                                 die_errno("accept returned");
1033                                         }
1034                                 }
1035                                 handle(incoming, &ss.sa, sslen);
1036                         }
1037                 }
1038         }
1039 }
1040
1041 #ifdef NO_POSIX_GOODIES
1042
1043 struct credentials;
1044
1045 static void drop_privileges(struct credentials *cred)
1046 {
1047         /* nothing */
1048 }
1049
1050 static struct credentials *prepare_credentials(const char *user_name,
1051     const char *group_name)
1052 {
1053         die("--user not supported on this platform");
1054 }
1055
1056 #else
1057
1058 struct credentials {
1059         struct passwd *pass;
1060         gid_t gid;
1061 };
1062
1063 static void drop_privileges(struct credentials *cred)
1064 {
1065         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1066             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1067                 die("cannot drop privileges");
1068 }
1069
1070 static struct credentials *prepare_credentials(const char *user_name,
1071     const char *group_name)
1072 {
1073         static struct credentials c;
1074
1075         c.pass = getpwnam(user_name);
1076         if (!c.pass)
1077                 die("user not found - %s", user_name);
1078
1079         if (!group_name)
1080                 c.gid = c.pass->pw_gid;
1081         else {
1082                 struct group *group = getgrnam(group_name);
1083                 if (!group)
1084                         die("group not found - %s", group_name);
1085
1086                 c.gid = group->gr_gid;
1087         }
1088
1089         return &c;
1090 }
1091 #endif
1092
1093 static void store_pid(const char *path)
1094 {
1095         FILE *f = fopen(path, "w");
1096         if (!f)
1097                 die_errno("cannot open pid file '%s'", path);
1098         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1099                 die_errno("failed to write pid file '%s'", path);
1100 }
1101
1102 static int serve(struct string_list *listen_addr, int listen_port,
1103     struct credentials *cred)
1104 {
1105         struct socketlist socklist = { NULL, 0, 0 };
1106
1107         socksetup(listen_addr, listen_port, &socklist);
1108         if (socklist.nr == 0)
1109                 die("unable to allocate any listen sockets on port %u",
1110                     listen_port);
1111
1112         drop_privileges(cred);
1113
1114         loginfo("Ready to rumble");
1115
1116         return service_loop(&socklist);
1117 }
1118
1119 int main(int argc, char **argv)
1120 {
1121         int listen_port = 0;
1122         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1123         int serve_mode = 0, inetd_mode = 0;
1124         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1125         int detach = 0;
1126         struct credentials *cred = NULL;
1127         int i;
1128
1129         git_setup_gettext();
1130
1131         git_extract_argv0_path(argv[0]);
1132
1133         for (i = 1; i < argc; i++) {
1134                 char *arg = argv[i];
1135                 const char *v;
1136
1137                 if (skip_prefix(arg, "--listen=", &v)) {
1138                         string_list_append(&listen_addr, xstrdup_tolower(v));
1139                         continue;
1140                 }
1141                 if (skip_prefix(arg, "--port=", &v)) {
1142                         char *end;
1143                         unsigned long n;
1144                         n = strtoul(v, &end, 0);
1145                         if (*v && !*end) {
1146                                 listen_port = n;
1147                                 continue;
1148                         }
1149                 }
1150                 if (!strcmp(arg, "--serve")) {
1151                         serve_mode = 1;
1152                         continue;
1153                 }
1154                 if (!strcmp(arg, "--inetd")) {
1155                         inetd_mode = 1;
1156                         log_syslog = 1;
1157                         continue;
1158                 }
1159                 if (!strcmp(arg, "--verbose")) {
1160                         verbose = 1;
1161                         continue;
1162                 }
1163                 if (!strcmp(arg, "--syslog")) {
1164                         log_syslog = 1;
1165                         continue;
1166                 }
1167                 if (!strcmp(arg, "--export-all")) {
1168                         export_all_trees = 1;
1169                         continue;
1170                 }
1171                 if (skip_prefix(arg, "--access-hook=", &v)) {
1172                         access_hook = v;
1173                         continue;
1174                 }
1175                 if (skip_prefix(arg, "--timeout=", &v)) {
1176                         timeout = atoi(v);
1177                         continue;
1178                 }
1179                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1180                         init_timeout = atoi(v);
1181                         continue;
1182                 }
1183                 if (skip_prefix(arg, "--max-connections=", &v)) {
1184                         max_connections = atoi(v);
1185                         if (max_connections < 0)
1186                                 max_connections = 0;            /* unlimited */
1187                         continue;
1188                 }
1189                 if (!strcmp(arg, "--strict-paths")) {
1190                         strict_paths = 1;
1191                         continue;
1192                 }
1193                 if (skip_prefix(arg, "--base-path=", &v)) {
1194                         base_path = v;
1195                         continue;
1196                 }
1197                 if (!strcmp(arg, "--base-path-relaxed")) {
1198                         base_path_relaxed = 1;
1199                         continue;
1200                 }
1201                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1202                         interpolated_path = v;
1203                         continue;
1204                 }
1205                 if (!strcmp(arg, "--reuseaddr")) {
1206                         reuseaddr = 1;
1207                         continue;
1208                 }
1209                 if (!strcmp(arg, "--user-path")) {
1210                         user_path = "";
1211                         continue;
1212                 }
1213                 if (skip_prefix(arg, "--user-path=", &v)) {
1214                         user_path = v;
1215                         continue;
1216                 }
1217                 if (skip_prefix(arg, "--pid-file=", &v)) {
1218                         pid_file = v;
1219                         continue;
1220                 }
1221                 if (!strcmp(arg, "--detach")) {
1222                         detach = 1;
1223                         log_syslog = 1;
1224                         continue;
1225                 }
1226                 if (skip_prefix(arg, "--user=", &v)) {
1227                         user_name = v;
1228                         continue;
1229                 }
1230                 if (skip_prefix(arg, "--group=", &v)) {
1231                         group_name = v;
1232                         continue;
1233                 }
1234                 if (skip_prefix(arg, "--enable=", &v)) {
1235                         enable_service(v, 1);
1236                         continue;
1237                 }
1238                 if (skip_prefix(arg, "--disable=", &v)) {
1239                         enable_service(v, 0);
1240                         continue;
1241                 }
1242                 if (skip_prefix(arg, "--allow-override=", &v)) {
1243                         make_service_overridable(v, 1);
1244                         continue;
1245                 }
1246                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1247                         make_service_overridable(v, 0);
1248                         continue;
1249                 }
1250                 if (!strcmp(arg, "--informative-errors")) {
1251                         informative_errors = 1;
1252                         continue;
1253                 }
1254                 if (!strcmp(arg, "--no-informative-errors")) {
1255                         informative_errors = 0;
1256                         continue;
1257                 }
1258                 if (!strcmp(arg, "--")) {
1259                         ok_paths = &argv[i+1];
1260                         break;
1261                 } else if (arg[0] != '-') {
1262                         ok_paths = &argv[i];
1263                         break;
1264                 }
1265
1266                 usage(daemon_usage);
1267         }
1268
1269         if (log_syslog) {
1270                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1271                 set_die_routine(daemon_die);
1272         } else
1273                 /* avoid splitting a message in the middle */
1274                 setvbuf(stderr, NULL, _IOFBF, 4096);
1275
1276         if (inetd_mode && (detach || group_name || user_name))
1277                 die("--detach, --user and --group are incompatible with --inetd");
1278
1279         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1280                 die("--listen= and --port= are incompatible with --inetd");
1281         else if (listen_port == 0)
1282                 listen_port = DEFAULT_GIT_PORT;
1283
1284         if (group_name && !user_name)
1285                 die("--group supplied without --user");
1286
1287         if (user_name)
1288                 cred = prepare_credentials(user_name, group_name);
1289
1290         if (strict_paths && (!ok_paths || !*ok_paths))
1291                 die("option --strict-paths requires a whitelist");
1292
1293         if (base_path && !is_directory(base_path))
1294                 die("base-path '%s' does not exist or is not a directory",
1295                     base_path);
1296
1297         if (inetd_mode) {
1298                 if (!freopen("/dev/null", "w", stderr))
1299                         die_errno("failed to redirect stderr to /dev/null");
1300         }
1301
1302         if (inetd_mode || serve_mode)
1303                 return execute();
1304
1305         if (detach) {
1306                 if (daemonize())
1307                         die("--detach not supported on this platform");
1308         } else
1309                 sanitize_stdfds();
1310
1311         if (pid_file)
1312                 store_pid(pid_file);
1313
1314         /* prepare argv for serving-processes */
1315         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1316         cld_argv[0] = argv[0];  /* git-daemon */
1317         cld_argv[1] = "--serve";
1318         for (i = 1; i < argc; ++i)
1319                 cld_argv[i+1] = argv[i];
1320         cld_argv[argc+1] = NULL;
1321
1322         return serve(&listen_addr, listen_port, cred);
1323 }