daemon.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3 #include "exec_cmd.h"
   4 #include "run-command.h"
   5 #include "strbuf.h"
   6 #include "string-list.h"
   7
   8 #include <syslog.h>
   9
  10 #ifndef HOST_NAME_MAX
  11 #define HOST_NAME_MAX 256
  12 #endif
  13
  14 #ifndef NI_MAXSERV
  15 #define NI_MAXSERV 32
  16 #endif
  17
  18 static int log_syslog;
  19 static int verbose;
  20 static int reuseaddr;
  21
  22 static const char daemon_usage[] =
  23 "git daemon [--verbose] [--syslog] [--export-all]\n"
  24 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  25 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  26 "           [--user-path | --user-path=<path>]\n"
  27 "           [--interpolated-path=<path>]\n"
  28 "           [--reuseaddr] [--detach] [--pid-file=<file>]\n"
  29 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  30 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  31 "                      [--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 char *base_path;
  43 static 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 linebuffered mode, the
  73                  * logging of different processes will not overlap
  74                  */
  75                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  76                 vfprintf(stderr, err, params);
  77                 fputc('\n', 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         pid_t pid;
 620         struct sockaddr_storage address;
 621 } *firstborn;
 622
 623 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 624 {
 625         struct child *newborn, **cradle;
 626
 627         newborn = xcalloc(1, sizeof(*newborn));
 628         live_children++;
 629         newborn->pid = pid;
 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 static void remove_child(pid_t pid)
 639 {
 640         struct child **cradle, *blanket;
 641
 642         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 643                 if (blanket->pid == pid) {
 644                         *cradle = blanket->next;
 645                         live_children--;
 646                         free(blanket);
 647                         break;
 648                 }
 649 }
 650
 651 /*
 652  * This gets called if the number of connections grows
 653  * past "max_connections".
 654  *
 655  * We kill the newest connection from a duplicate IP.
 656  */
 657 static void kill_some_child(void)
 658 {
 659         const struct child *blanket, *next;
 660
 661         if (!(blanket = firstborn))
 662                 return;
 663
 664         for (; (next = blanket->next); blanket = next)
 665                 if (!addrcmp(&blanket->address, &next->address)) {
 666                         kill(blanket->pid, SIGTERM);
 667                         break;
 668                 }
 669 }
 670
 671 static void check_dead_children(void)
 672 {
 673         int status;
 674         pid_t pid;
 675
 676         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 677                 const char *dead = "";
 678                 remove_child(pid);
 679                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 680                         dead = " (with error)";
 681                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 682         }
 683 }
 684
 685 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 686 {
 687         pid_t pid;
 688
 689         if (max_connections && live_children >= max_connections) {
 690                 kill_some_child();
 691                 sleep(1);  /* give it some time to die */
 692                 check_dead_children();
 693                 if (live_children >= max_connections) {
 694                         close(incoming);
 695                         logerror("Too many children, dropping connection");
 696                         return;
 697                 }
 698         }
 699
 700         if ((pid = fork())) {
 701                 close(incoming);
 702                 if (pid < 0) {
 703                         logerror("Couldn't fork %s", strerror(errno));
 704                         return;
 705                 }
 706
 707                 add_child(pid, addr, addrlen);
 708                 return;
 709         }
 710
 711         dup2(incoming, 0);
 712         dup2(incoming, 1);
 713         close(incoming);
 714
 715         exit(execute(addr));
 716 }
 717
 718 static void child_handler(int signo)
 719 {
 720         /*
 721          * Otherwise empty handler because systemcalls will get interrupted
 722          * upon signal receipt
 723          * SysV needs the handler to be rearmed
 724          */
 725         signal(SIGCHLD, child_handler);
 726 }
 727
 728 static int set_reuse_addr(int sockfd)
 729 {
 730         int on = 1;
 731
 732         if (!reuseaddr)
 733                 return 0;
 734         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 735                           &on, sizeof(on));
 736 }
 737
 738 struct socketlist {
 739         int *list;
 740         size_t nr;
 741         size_t alloc;
 742 };
 743
 744 #ifndef NO_IPV6
 745
 746 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 747 {
 748         int socknum = 0;
 749         int maxfd = -1;
 750         char pbuf[NI_MAXSERV];
 751         struct addrinfo hints, *ai0, *ai;
 752         int gai;
 753         long flags;
 754
 755         sprintf(pbuf, "%d", listen_port);
 756         memset(&hints, 0, sizeof(hints));
 757         hints.ai_family = AF_UNSPEC;
 758         hints.ai_socktype = SOCK_STREAM;
 759         hints.ai_protocol = IPPROTO_TCP;
 760         hints.ai_flags = AI_PASSIVE;
 761
 762         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 763         if (gai) {
 764                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 765                 return 0;
 766         }
 767
 768         for (ai = ai0; ai; ai = ai->ai_next) {
 769                 int sockfd;
 770
 771                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 772                 if (sockfd < 0)
 773                         continue;
 774                 if (sockfd >= FD_SETSIZE) {
 775                         logerror("Socket descriptor too large");
 776                         close(sockfd);
 777                         continue;
 778                 }
 779
 780 #ifdef IPV6_V6ONLY
 781                 if (ai->ai_family == AF_INET6) {
 782                         int on = 1;
 783                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 784                                    &on, sizeof(on));
 785                         /* Note: error is not fatal */
 786                 }
 787 #endif
 788
 789                 if (set_reuse_addr(sockfd)) {
 790                         close(sockfd);
 791                         continue;
 792                 }
 793
 794                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 795                         close(sockfd);
 796                         continue;       /* not fatal */
 797                 }
 798                 if (listen(sockfd, 5) < 0) {
 799                         close(sockfd);
 800                         continue;       /* not fatal */
 801                 }
 802
 803                 flags = fcntl(sockfd, F_GETFD, 0);
 804                 if (flags >= 0)
 805                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 806
 807                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 808                 socklist->list[socklist->nr++] = sockfd;
 809                 socknum++;
 810
 811                 if (maxfd < sockfd)
 812                         maxfd = sockfd;
 813         }
 814
 815         freeaddrinfo(ai0);
 816
 817         return socknum;
 818 }
 819
 820 #else /* NO_IPV6 */
 821
 822 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 823 {
 824         struct sockaddr_in sin;
 825         int sockfd;
 826         long flags;
 827
 828         memset(&sin, 0, sizeof sin);
 829         sin.sin_family = AF_INET;
 830         sin.sin_port = htons(listen_port);
 831
 832         if (listen_addr) {
 833                 /* Well, host better be an IP address here. */
 834                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 835                         return 0;
 836         } else {
 837                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 838         }
 839
 840         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 841         if (sockfd < 0)
 842                 return 0;
 843
 844         if (set_reuse_addr(sockfd)) {
 845                 close(sockfd);
 846                 return 0;
 847         }
 848
 849         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 850                 close(sockfd);
 851                 return 0;
 852         }
 853
 854         if (listen(sockfd, 5) < 0) {
 855                 close(sockfd);
 856                 return 0;
 857         }
 858
 859         flags = fcntl(sockfd, F_GETFD, 0);
 860         if (flags >= 0)
 861                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 862
 863         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 864         socklist->list[socklist->nr++] = sockfd;
 865         return 1;
 866 }
 867
 868 #endif
 869
 870 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 871 {
 872         if (!listen_addr->nr)
 873                 setup_named_sock(NULL, listen_port, socklist);
 874         else {
 875                 int i, socknum;
 876                 for (i = 0; i < listen_addr->nr; i++) {
 877                         socknum = setup_named_sock(listen_addr->items[i].string,
 878                                                    listen_port, socklist);
 879
 880                         if (socknum == 0)
 881                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 882                                          listen_addr->items[i].string, listen_port);
 883                 }
 884         }
 885 }
 886
 887 static int service_loop(struct socketlist *socklist)
 888 {
 889         struct pollfd *pfd;
 890         int i;
 891
 892         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 893
 894         for (i = 0; i < socklist->nr; i++) {
 895                 pfd[i].fd = socklist->list[i];
 896                 pfd[i].events = POLLIN;
 897         }
 898
 899         signal(SIGCHLD, child_handler);
 900
 901         for (;;) {
 902                 int i;
 903
 904                 check_dead_children();
 905
 906                 if (poll(pfd, socklist->nr, -1) < 0) {
 907                         if (errno != EINTR) {
 908                                 logerror("Poll failed, resuming: %s",
 909                                       strerror(errno));
 910                                 sleep(1);
 911                         }
 912                         continue;
 913                 }
 914
 915                 for (i = 0; i < socklist->nr; i++) {
 916                         if (pfd[i].revents & POLLIN) {
 917                                 struct sockaddr_storage ss;
 918                                 unsigned int sslen = sizeof(ss);
 919                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 920                                 if (incoming < 0) {
 921                                         switch (errno) {
 922                                         case EAGAIN:
 923                                         case EINTR:
 924                                         case ECONNABORTED:
 925                                                 continue;
 926                                         default:
 927                                                 die_errno("accept returned");
 928                                         }
 929                                 }
 930                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 931                         }
 932                 }
 933         }
 934 }
 935
 936 /* if any standard file descriptor is missing open it to /dev/null */
 937 static void sanitize_stdfds(void)
 938 {
 939         int fd = open("/dev/null", O_RDWR, 0);
 940         while (fd != -1 && fd < 2)
 941                 fd = dup(fd);
 942         if (fd == -1)
 943                 die_errno("open /dev/null or dup failed");
 944         if (fd > 2)
 945                 close(fd);
 946 }
 947
 948 static void daemonize(void)
 949 {
 950         switch (fork()) {
 951                 case 0:
 952                         break;
 953                 case -1:
 954                         die_errno("fork failed");
 955                 default:
 956                         exit(0);
 957         }
 958         if (setsid() == -1)
 959                 die_errno("setsid failed");
 960         close(0);
 961         close(1);
 962         close(2);
 963         sanitize_stdfds();
 964 }
 965
 966 static void store_pid(const char *path)
 967 {
 968         FILE *f = fopen(path, "w");
 969         if (!f)
 970                 die_errno("cannot open pid file '%s'", path);
 971         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 972                 die_errno("failed to write pid file '%s'", path);
 973 }
 974
 975 static int serve(struct string_list *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 976 {
 977         struct socketlist socklist = { NULL, 0, 0 };
 978
 979         socksetup(listen_addr, listen_port, &socklist);
 980         if (socklist.nr == 0)
 981                 die("unable to allocate any listen sockets on port %u",
 982                     listen_port);
 983
 984         if (pass && gid &&
 985             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 986              setuid(pass->pw_uid)))
 987                 die("cannot drop privileges");
 988
 989         return service_loop(&socklist);
 990 }
 991
 992 int main(int argc, char **argv)
 993 {
 994         int listen_port = 0;
 995         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
 996         int inetd_mode = 0;
 997         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 998         int detach = 0;
 999         struct passwd *pass = NULL;
1000         struct group *group;
1001         gid_t gid = 0;
1002         int i;
1003
1004         git_extract_argv0_path(argv[0]);
1005
1006         for (i = 1; i < argc; i++) {
1007                 char *arg = argv[i];
1008
1009                 if (!prefixcmp(arg, "--listen=")) {
1010                         string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1011                         continue;
1012                 }
1013                 if (!prefixcmp(arg, "--port=")) {
1014                         char *end;
1015                         unsigned long n;
1016                         n = strtoul(arg+7, &end, 0);
1017                         if (arg[7] && !*end) {
1018                                 listen_port = n;
1019                                 continue;
1020                         }
1021                 }
1022                 if (!strcmp(arg, "--inetd")) {
1023                         inetd_mode = 1;
1024                         log_syslog = 1;
1025                         continue;
1026                 }
1027                 if (!strcmp(arg, "--verbose")) {
1028                         verbose = 1;
1029                         continue;
1030                 }
1031                 if (!strcmp(arg, "--syslog")) {
1032                         log_syslog = 1;
1033                         continue;
1034                 }
1035                 if (!strcmp(arg, "--export-all")) {
1036                         export_all_trees = 1;
1037                         continue;
1038                 }
1039                 if (!prefixcmp(arg, "--timeout=")) {
1040                         timeout = atoi(arg+10);
1041                         continue;
1042                 }
1043                 if (!prefixcmp(arg, "--init-timeout=")) {
1044                         init_timeout = atoi(arg+15);
1045                         continue;
1046                 }
1047                 if (!prefixcmp(arg, "--max-connections=")) {
1048                         max_connections = atoi(arg+18);
1049                         if (max_connections < 0)
1050                                 max_connections = 0;            /* unlimited */
1051                         continue;
1052                 }
1053                 if (!strcmp(arg, "--strict-paths")) {
1054                         strict_paths = 1;
1055                         continue;
1056                 }
1057                 if (!prefixcmp(arg, "--base-path=")) {
1058                         base_path = arg+12;
1059                         continue;
1060                 }
1061                 if (!strcmp(arg, "--base-path-relaxed")) {
1062                         base_path_relaxed = 1;
1063                         continue;
1064                 }
1065                 if (!prefixcmp(arg, "--interpolated-path=")) {
1066                         interpolated_path = arg+20;
1067                         continue;
1068                 }
1069                 if (!strcmp(arg, "--reuseaddr")) {
1070                         reuseaddr = 1;
1071                         continue;
1072                 }
1073                 if (!strcmp(arg, "--user-path")) {
1074                         user_path = "";
1075                         continue;
1076                 }
1077                 if (!prefixcmp(arg, "--user-path=")) {
1078                         user_path = arg + 12;
1079                         continue;
1080                 }
1081                 if (!prefixcmp(arg, "--pid-file=")) {
1082                         pid_file = arg + 11;
1083                         continue;
1084                 }
1085                 if (!strcmp(arg, "--detach")) {
1086                         detach = 1;
1087                         log_syslog = 1;
1088                         continue;
1089                 }
1090                 if (!prefixcmp(arg, "--user=")) {
1091                         user_name = arg + 7;
1092                         continue;
1093                 }
1094                 if (!prefixcmp(arg, "--group=")) {
1095                         group_name = arg + 8;
1096                         continue;
1097                 }
1098                 if (!prefixcmp(arg, "--enable=")) {
1099                         enable_service(arg + 9, 1);
1100                         continue;
1101                 }
1102                 if (!prefixcmp(arg, "--disable=")) {
1103                         enable_service(arg + 10, 0);
1104                         continue;
1105                 }
1106                 if (!prefixcmp(arg, "--allow-override=")) {
1107                         make_service_overridable(arg + 17, 1);
1108                         continue;
1109                 }
1110                 if (!prefixcmp(arg, "--forbid-override=")) {
1111                         make_service_overridable(arg + 18, 0);
1112                         continue;
1113                 }
1114                 if (!strcmp(arg, "--")) {
1115                         ok_paths = &argv[i+1];
1116                         break;
1117                 } else if (arg[0] != '-') {
1118                         ok_paths = &argv[i];
1119                         break;
1120                 }
1121
1122                 usage(daemon_usage);
1123         }
1124
1125         if (log_syslog) {
1126                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1127                 set_die_routine(daemon_die);
1128         } else
1129                 /* avoid splitting a message in the middle */
1130                 setvbuf(stderr, NULL, _IOLBF, 0);
1131
1132         if (inetd_mode && (group_name || user_name))
1133                 die("--user and --group are incompatible with --inetd");
1134
1135         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1136                 die("--listen= and --port= are incompatible with --inetd");
1137         else if (listen_port == 0)
1138                 listen_port = DEFAULT_GIT_PORT;
1139
1140         if (group_name && !user_name)
1141                 die("--group supplied without --user");
1142
1143         if (user_name) {
1144                 pass = getpwnam(user_name);
1145                 if (!pass)
1146                         die("user not found - %s", user_name);
1147
1148                 if (!group_name)
1149                         gid = pass->pw_gid;
1150                 else {
1151                         group = getgrnam(group_name);
1152                         if (!group)
1153                                 die("group not found - %s", group_name);
1154
1155                         gid = group->gr_gid;
1156                 }
1157         }
1158
1159         if (strict_paths && (!ok_paths || !*ok_paths))
1160                 die("option --strict-paths requires a whitelist");
1161
1162         if (base_path && !is_directory(base_path))
1163                 die("base-path '%s' does not exist or is not a directory",
1164                     base_path);
1165
1166         if (inetd_mode) {
1167                 struct sockaddr_storage ss;
1168                 struct sockaddr *peer = (struct sockaddr *)&ss;
1169                 socklen_t slen = sizeof(ss);
1170
1171                 if (!freopen("/dev/null", "w", stderr))
1172                         die_errno("failed to redirect stderr to /dev/null");
1173
1174                 if (getpeername(0, peer, &slen))
1175                         peer = NULL;
1176
1177                 return execute(peer);
1178         }
1179
1180         if (detach) {
1181                 daemonize();
1182                 loginfo("Ready to rumble");
1183         }
1184         else
1185                 sanitize_stdfds();
1186
1187         if (pid_file)
1188                 store_pid(pid_file);
1189
1190         return serve(&listen_addr, listen_port, pass, gid);
1191 }