| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Freeze a file system under remote control |
| 4 | * |
| 5 | * (c) 2012 Mark Wooding |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the `rsync-backup' program. |
| 11 | * |
| 12 | * rsync-backup is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2 of the License, or |
| 15 | * (at your option) any later version. |
| 16 | * |
| 17 | * rsync-backup is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License along |
| 23 | * with rsync-backup; if not, write to the Free Software Foundation, |
| 24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | */ |
| 26 | |
| 27 | /*----- Header files ------------------------------------------------------*/ |
| 28 | |
| 29 | #include <assert.h> |
| 30 | #include <errno.h> |
| 31 | #include <limits.h> |
| 32 | #include <signal.h> |
| 33 | #include <stdarg.h> |
| 34 | #include <stdio.h> |
| 35 | #include <string.h> |
| 36 | #include <stdlib.h> |
| 37 | #include <time.h> |
| 38 | |
| 39 | #include <sys/types.h> |
| 40 | #include <sys/time.h> |
| 41 | #include <sys/select.h> |
| 42 | #include <unistd.h> |
| 43 | #include <fcntl.h> |
| 44 | #include <sys/ioctl.h> |
| 45 | |
| 46 | #include <linux/fs.h> |
| 47 | |
| 48 | #include <sys/socket.h> |
| 49 | #include <arpa/inet.h> |
| 50 | #include <netinet/in.h> |
| 51 | #include <netdb.h> |
| 52 | |
| 53 | #include <mLib/alloc.h> |
| 54 | #include <mLib/dstr.h> |
| 55 | #include <mLib/base64.h> |
| 56 | #include <mLib/fdflags.h> |
| 57 | #include <mLib/macros.h> |
| 58 | #include <mLib/mdwopt.h> |
| 59 | #include <mLib/quis.h> |
| 60 | #include <mLib/report.h> |
| 61 | #include <mLib/sub.h> |
| 62 | #include <mLib/tv.h> |
| 63 | |
| 64 | /*----- Magic constants ---------------------------------------------------*/ |
| 65 | |
| 66 | #define COOKIESZ 16 /* Size of authentication cookie */ |
| 67 | #define TO_CONNECT 30 /* Timeout for incoming connection */ |
| 68 | #define TO_KEEPALIVE 60 /* Timeout between keepalives */ |
| 69 | |
| 70 | /*----- Utility functions -------------------------------------------------*/ |
| 71 | |
| 72 | static int getuint(const char *p, const char *q) |
| 73 | { |
| 74 | unsigned long i; |
| 75 | int e = errno; |
| 76 | char *qq; |
| 77 | |
| 78 | if (!q) q = p + strlen(p); |
| 79 | errno = 0; |
| 80 | i = strtoul(p, &qq, 0); |
| 81 | if (errno || qq < q || i > INT_MAX) |
| 82 | die(1, "invalid integer `%s'", p); |
| 83 | errno = e; |
| 84 | return ((int)i); |
| 85 | } |
| 86 | |
| 87 | #ifdef DEBUG |
| 88 | # define D(x) x |
| 89 | #else |
| 90 | # define D(x) |
| 91 | #endif |
| 92 | |
| 93 | /*----- Token management --------------------------------------------------*/ |
| 94 | |
| 95 | struct token { |
| 96 | const char *label; |
| 97 | char tok[(COOKIESZ + 2)*4/3 + 1]; |
| 98 | }; |
| 99 | |
| 100 | #define TOKENS(_) \ |
| 101 | _(FREEZE) \ |
| 102 | _(FROZEN) \ |
| 103 | _(KEEPALIVE) \ |
| 104 | _(THAW) \ |
| 105 | _(THAWED) |
| 106 | |
| 107 | enum { |
| 108 | #define ENUM(tok) T_##tok, |
| 109 | TOKENS(ENUM) |
| 110 | #undef ENUM |
| 111 | T_LIMIT |
| 112 | }; |
| 113 | |
| 114 | enum { |
| 115 | #define MASK(tok) TF_##tok = 1u << T_##tok, |
| 116 | TOKENS(MASK) |
| 117 | #undef ENUM |
| 118 | TF_ALL = (1u << T_LIMIT) - 1u |
| 119 | }; |
| 120 | |
| 121 | static struct token toktab[] = { |
| 122 | #define INIT(tok) { #tok }, |
| 123 | TOKENS(INIT) |
| 124 | #undef INIT |
| 125 | { 0 } |
| 126 | }; |
| 127 | |
| 128 | static void inittoks(void) |
| 129 | { |
| 130 | static struct token *t, *tt; |
| 131 | unsigned char buf[COOKIESZ]; |
| 132 | int fd; |
| 133 | ssize_t n; |
| 134 | base64_ctx bc; |
| 135 | dstr d = DSTR_INIT; |
| 136 | |
| 137 | if ((fd = open("/dev/urandom", O_RDONLY)) < 0) |
| 138 | die(2, "open (urandom): %s", strerror(errno)); |
| 139 | |
| 140 | for (t = toktab; t->label; t++) { |
| 141 | again: |
| 142 | n = read(fd, buf, COOKIESZ); |
| 143 | if (n < 0) die(2, "read (urandom): %s", strerror(errno)); |
| 144 | else if (n < COOKIESZ) die(2, "read (urandom): short read"); |
| 145 | base64_init(&bc); |
| 146 | base64_encode(&bc, buf, COOKIESZ, &d); |
| 147 | base64_encode(&bc, 0, 0, &d); |
| 148 | dstr_putz(&d); |
| 149 | |
| 150 | for (tt = toktab; tt < t; tt++) { |
| 151 | if (strcmp(d.buf, tt->tok) == 0) |
| 152 | goto again; |
| 153 | } |
| 154 | |
| 155 | assert(d.len < sizeof(t->tok)); |
| 156 | memcpy(t->tok, d.buf, d.len + 1); |
| 157 | dstr_reset(&d); |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | struct tokmatch { |
| 162 | unsigned tf; /* Possible token matches */ |
| 163 | size_t o; /* Offset into token string */ |
| 164 | unsigned f; /* Flags */ |
| 165 | #define TMF_CR 1u /* Seen trailing carriage-return */ |
| 166 | }; |
| 167 | |
| 168 | static void tokmatch_init(struct tokmatch *tm) |
| 169 | { tm->tf = TF_ALL; tm->o = 0; tm->f = 0; } |
| 170 | |
| 171 | static int tokmatch_update(struct tokmatch *tm, int ch) |
| 172 | { |
| 173 | const struct token *t; |
| 174 | unsigned tf; |
| 175 | |
| 176 | switch (ch) { |
| 177 | case '\n': |
| 178 | for (t = toktab, tf = 1; t->label; t++, tf <<= 1) { |
| 179 | if ((tm->tf & tf) && !t->tok[tm->o]) |
| 180 | return (tf); |
| 181 | } |
| 182 | return (-1); |
| 183 | case '\r': |
| 184 | for (t = toktab, tf = 1; t->label; t++, tf <<= 1) { |
| 185 | if ((tm->tf & tf) && !t->tok[tm->o] && !(tm->f & TMF_CR)) |
| 186 | tm->f |= TMF_CR; |
| 187 | else |
| 188 | tm->tf &= ~tf; |
| 189 | } |
| 190 | break; |
| 191 | default: |
| 192 | for (t = toktab, tf = 1; t->label; t++, tf <<= 1) { |
| 193 | if ((tm->tf & tf) && ch != t->tok[tm->o]) |
| 194 | tm->tf &= ~tf; |
| 195 | } |
| 196 | tm->o++; |
| 197 | break; |
| 198 | } |
| 199 | return (0); |
| 200 | } |
| 201 | |
| 202 | static int writetok(unsigned i, int fd) |
| 203 | { |
| 204 | static const char nl = '\n'; |
| 205 | const struct token *t = &toktab[i]; |
| 206 | size_t n = strlen(t->tok); |
| 207 | |
| 208 | errno = EIO; |
| 209 | if (write(fd, t->tok, n) < n || |
| 210 | write(fd, &nl, 1) < 1) |
| 211 | return (-1); |
| 212 | return (0); |
| 213 | } |
| 214 | |
| 215 | /*----- Data structures ---------------------------------------------------*/ |
| 216 | |
| 217 | struct client { |
| 218 | struct client *next; /* Links in the client chain */ |
| 219 | int fd; /* File descriptor for socket */ |
| 220 | struct tokmatch tm; /* Token matching context */ |
| 221 | }; |
| 222 | |
| 223 | /*----- Static variables --------------------------------------------------*/ |
| 224 | |
| 225 | static int *fs; /* File descriptors for targets */ |
| 226 | static char **fsname; /* File system names */ |
| 227 | static size_t nfs; /* Number of descriptors */ |
| 228 | |
| 229 | /*----- Cleanup -----------------------------------------------------------*/ |
| 230 | |
| 231 | #define EOM ((char *)0) |
| 232 | static void EXECL_LIKE(0) emerg(const char *msg, ...) |
| 233 | { |
| 234 | va_list ap; |
| 235 | |
| 236 | #define MSG(m) \ |
| 237 | do { const char *m_ = m; if (write(2, m_, strlen(m_))); } while (0) |
| 238 | |
| 239 | va_start(ap, msg); |
| 240 | MSG(QUIS); MSG(": "); |
| 241 | do { |
| 242 | MSG(msg); |
| 243 | msg = va_arg(ap, const char *); |
| 244 | } while (msg != EOM); |
| 245 | MSG("\n"); |
| 246 | |
| 247 | #undef MSG |
| 248 | } |
| 249 | |
| 250 | static void partial_cleanup(size_t n) |
| 251 | { |
| 252 | int i; |
| 253 | int bad = 0; |
| 254 | |
| 255 | for (i = 0; i < n; i++) { |
| 256 | if (fs[i] == -1) |
| 257 | emerg("not really thawing ", fsname[i], EOM); |
| 258 | else if (fs[i] != -2) { |
| 259 | if (ioctl(fs[i], FITHAW, 0)) { |
| 260 | emerg("VERY BAD! failed to thaw ", |
| 261 | fsname[i], ": ", strerror(errno), EOM); |
| 262 | bad = 1; |
| 263 | } |
| 264 | close(fs[i]); |
| 265 | } |
| 266 | fs[i] = -2; |
| 267 | } |
| 268 | if (bad) _exit(112); |
| 269 | } |
| 270 | |
| 271 | static void cleanup(void) { partial_cleanup(nfs); } |
| 272 | |
| 273 | static int sigcatch[] = { |
| 274 | SIGINT, SIGQUIT, SIGTERM, SIGHUP, SIGALRM, |
| 275 | SIGILL, SIGSEGV, SIGBUS, SIGFPE, SIGABRT |
| 276 | }; |
| 277 | |
| 278 | static void NORETURN sigmumble(int sig) |
| 279 | { |
| 280 | sigset_t ss; |
| 281 | |
| 282 | cleanup(); |
| 283 | emerg(strsignal(sig), EOM); |
| 284 | |
| 285 | signal(sig, SIG_DFL); |
| 286 | sigemptyset(&ss); sigaddset(&ss, sig); |
| 287 | sigprocmask(SIG_UNBLOCK, &ss, 0); |
| 288 | raise(sig); |
| 289 | _exit(4); |
| 290 | } |
| 291 | |
| 292 | /*----- Help functions ----------------------------------------------------*/ |
| 293 | |
| 294 | static void version(FILE *fp) |
| 295 | { pquis(fp, "$, " PACKAGE " version " VERSION "\n"); } |
| 296 | static void usage(FILE *fp) |
| 297 | { pquis(fp, "Usage: $ [-n] [-a ADDR] [-p LOPORT[-HIPORT]] FILSYS ...\n"); } |
| 298 | |
| 299 | static void help(FILE *fp) |
| 300 | { |
| 301 | version(fp); putc('\n', fp); |
| 302 | usage(fp); |
| 303 | fputs("\n\ |
| 304 | Freezes a filesystem temporarily, with some measure of safety.\n\ |
| 305 | \n\ |
| 306 | The program listens for connections on a TCP port, and prints a number of\n\ |
| 307 | lines:\n\ |
| 308 | \n\ |
| 309 | PORT <port>\n\ |
| 310 | TOKEN FREEZE <token>\n\ |
| 311 | TOKEN FROZEN <token>\n\ |
| 312 | TOKEN KEEPALIVE <token>\n\ |
| 313 | TOKEN THAW <token>\n\ |
| 314 | TOKEN THAWED <token>\n\ |
| 315 | READY\n\ |
| 316 | \n\ |
| 317 | to standard output. You must connect to the <port>, using TCP, and send\n\ |
| 318 | the FREEZE token followed by a newline within a short period of time. The\n\ |
| 319 | filesystems will then be frozen, and the FROZEN token written to the\n\ |
| 320 | connection. In order to keep the file system frozen, you must keep the\n\ |
| 321 | connection open, and periodically echo the KEEPALIVE token to it. To\n\ |
| 322 | release the filesystems, write the THAW token to the connection, followed\n\ |
| 323 | by a newline; the filesystem will be thawed, and the THAWED token echoed\n\ |
| 324 | back. If the connection closes, or no valid message is received within a\n\ |
| 325 | set period of time, or the program receives one of a variety of signals or\n\ |
| 326 | otherwise becomes unhappy, the filesystems are thawed again.\n\ |
| 327 | \n\ |
| 328 | The program exits with status zero if everything worked as planned, while\n\ |
| 329 | nonzero codes indicate failures of various kinds (see the manual); an exit\n\ |
| 330 | status of 112 means that thawing a filesystem failed.\n\ |
| 331 | \n\ |
| 332 | Options:\n\ |
| 333 | \n\ |
| 334 | -h, --help Print this help text.\n\ |
| 335 | -v, --version Print the program version number.\n\ |
| 336 | -u, --usage Print a short usage message.\n\ |
| 337 | \n\ |
| 338 | -a, --address=ADDR Listen only on ADDR.\n\ |
| 339 | -n, --not-really Don't really freeze or thaw filesystems.\n\ |
| 340 | -p, --port-range=LO[-HI] Select a port number between LO and HI.\n\ |
| 341 | If HI is omitted, choose only LO.\n\ |
| 342 | ", fp); |
| 343 | } |
| 344 | |
| 345 | /*----- Main program ------------------------------------------------------*/ |
| 346 | |
| 347 | int main(int argc, char *argv[]) |
| 348 | { |
| 349 | char buf[256]; |
| 350 | int loport = -1, hiport = -1; |
| 351 | int sk, fd, maxfd; |
| 352 | struct sockaddr_in sin; |
| 353 | socklen_t sasz; |
| 354 | struct hostent *h; |
| 355 | const char *p, *q; |
| 356 | struct timeval now, when, delta; |
| 357 | struct client *clients = 0, *c, **cc; |
| 358 | const struct token *t; |
| 359 | struct tokmatch tm; |
| 360 | fd_set fdin; |
| 361 | int i; |
| 362 | ssize_t n; |
| 363 | unsigned f = 0; |
| 364 | #define f_bogus 0x01u |
| 365 | #define f_notreally 0x02u |
| 366 | |
| 367 | ego(argv[0]); |
| 368 | sub_init(); |
| 369 | |
| 370 | /* --- Partially initialize the socket address --- */ |
| 371 | |
| 372 | sin.sin_family = AF_INET; |
| 373 | sin.sin_addr.s_addr = INADDR_ANY; |
| 374 | sin.sin_port = 0; |
| 375 | |
| 376 | /* --- Parse the command line --- */ |
| 377 | |
| 378 | for (;;) { |
| 379 | static struct option opts[] = { |
| 380 | { "help", 0, 0, 'h' }, |
| 381 | { "version", 0, 0, 'v' }, |
| 382 | { "usage", 0, 0, 'u' }, |
| 383 | { "address", OPTF_ARGREQ, 0, 'a' }, |
| 384 | { "not-really", 0, 0, 'n' }, |
| 385 | { "port-range", OPTF_ARGREQ, 0, 'p' }, |
| 386 | { 0, 0, 0, 0 } |
| 387 | }; |
| 388 | |
| 389 | if ((i = mdwopt(argc, argv, "hvua:np:", opts, 0, 0, 0)) < 0) break; |
| 390 | switch (i) { |
| 391 | case 'h': help(stdout); exit(0); |
| 392 | case 'v': version(stdout); exit(0); |
| 393 | case 'u': usage(stdout); exit(0); |
| 394 | case 'a': |
| 395 | if ((h = gethostbyname(optarg)) == 0) { |
| 396 | die(1, "failed to resolve address `%s': %s", |
| 397 | optarg, hstrerror(h_errno)); |
| 398 | } |
| 399 | if (h->h_addrtype != AF_INET) |
| 400 | die(1, "unexpected address type resolving `%s'", optarg); |
| 401 | assert(h->h_length == sizeof(sin.sin_addr)); |
| 402 | memcpy(&sin.sin_addr, h->h_addr, sizeof(sin.sin_addr)); |
| 403 | break; |
| 404 | case 'n': f |= f_notreally; break; |
| 405 | case 'p': |
| 406 | if ((p = strchr(optarg, '-')) == 0) |
| 407 | loport = hiport = getuint(optarg, 0); |
| 408 | else { |
| 409 | loport = getuint(optarg, p); |
| 410 | hiport = getuint(p + 1, 0); |
| 411 | } |
| 412 | break; |
| 413 | default: f |= f_bogus; break; |
| 414 | } |
| 415 | } |
| 416 | if (f & f_bogus) { usage(stderr); exit(1); } |
| 417 | if (optind >= argc) { usage(stderr); exit(1); } |
| 418 | |
| 419 | /* --- Open the file systems --- */ |
| 420 | |
| 421 | nfs = argc - optind; |
| 422 | fsname = &argv[optind]; |
| 423 | fs = xmalloc(nfs*sizeof(*fs)); |
| 424 | for (i = 0; i < nfs; i++) { |
| 425 | if ((fs[i] = open(fsname[i], O_RDONLY)) < 0) |
| 426 | die(2, "open (%s): %s", fsname[i], strerror(errno)); |
| 427 | } |
| 428 | |
| 429 | if (f & f_notreally) { |
| 430 | for (i = 0; i < nfs; i++) { |
| 431 | close(fs[i]); |
| 432 | fs[i] = -1; |
| 433 | } |
| 434 | } |
| 435 | |
| 436 | /* --- Generate random tokens --- */ |
| 437 | |
| 438 | inittoks(); |
| 439 | |
| 440 | /* --- Create the listening socket --- */ |
| 441 | |
| 442 | if ((sk = socket(PF_INET, SOCK_STREAM, 0)) < 0) |
| 443 | die(2, "socket: %s", strerror(errno)); |
| 444 | i = 1; |
| 445 | if (setsockopt(sk, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i))) |
| 446 | die(2, "setsockopt (reuseaddr): %s", strerror(errno)); |
| 447 | if (fdflags(sk, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC)) |
| 448 | die(2, "fdflags: %s", strerror(errno)); |
| 449 | if (loport < 0 || loport == hiport) { |
| 450 | if (loport >= 0) sin.sin_port = htons(loport); |
| 451 | if (bind(sk, (struct sockaddr *)&sin, sizeof(sin))) |
| 452 | die(2, "bind: %s", strerror(errno)); |
| 453 | } else if (hiport != loport) { |
| 454 | for (i = loport; i <= hiport; i++) { |
| 455 | sin.sin_port = htons(i); |
| 456 | if (bind(sk, (struct sockaddr *)&sin, sizeof(sin)) >= 0) break; |
| 457 | else if (errno != EADDRINUSE) |
| 458 | die(2, "bind: %s", strerror(errno)); |
| 459 | } |
| 460 | if (i > hiport) die(2, "bind: all ports in use"); |
| 461 | } |
| 462 | if (listen(sk, 5)) die(2, "listen: %s", strerror(errno)); |
| 463 | |
| 464 | /* --- Tell the caller how to connect to us, and start the timer --- */ |
| 465 | |
| 466 | sasz = sizeof(sin); |
| 467 | if (getsockname(sk, (struct sockaddr *)&sin, &sasz)) |
| 468 | die(2, "getsockname (listen): %s", strerror(errno)); |
| 469 | printf("PORT %d\n", ntohs(sin.sin_port)); |
| 470 | for (t = toktab; t->label; t++) |
| 471 | printf("TOKEN %s %s\n", t->label, t->tok); |
| 472 | printf("READY\n"); |
| 473 | if (fflush(stdout) || ferror(stdout)) |
| 474 | die(2, "write (stdout, rubric): %s", strerror(errno)); |
| 475 | gettimeofday(&now, 0); TV_ADDL(&when, &now, TO_CONNECT, 0); |
| 476 | |
| 477 | /* --- Collect incoming connections, and check for the cookie --- * |
| 478 | * |
| 479 | * This is the tricky part. |
| 480 | */ |
| 481 | |
| 482 | for (;;) { |
| 483 | FD_ZERO(&fdin); |
| 484 | FD_SET(sk, &fdin); |
| 485 | maxfd = sk; |
| 486 | for (c = clients; c; c = c->next) { |
| 487 | FD_SET(c->fd, &fdin); |
| 488 | if (c->fd > maxfd) maxfd = c->fd; |
| 489 | } |
| 490 | TV_SUB(&delta, &when, &now); |
| 491 | if (select(maxfd + 1, &fdin, 0, 0, &delta) < 0) |
| 492 | die(2, "select (accept): %s", strerror(errno)); |
| 493 | gettimeofday(&now, 0); |
| 494 | |
| 495 | if (TV_CMP(&now, >=, &when)) die(3, "timeout (accept)"); |
| 496 | |
| 497 | if (FD_ISSET(sk, &fdin)) { |
| 498 | sasz = sizeof(sin); |
| 499 | fd = accept(sk, (struct sockaddr *)&sin, &sasz); |
| 500 | if (fd >= 0) { |
| 501 | if (fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC) < 0) |
| 502 | die(2, "fdflags: %s", strerror(errno)); |
| 503 | c = CREATE(struct client); |
| 504 | c->next = clients; c->fd = fd; tokmatch_init(&c->tm); |
| 505 | clients = c; |
| 506 | } |
| 507 | #ifdef DEBUG |
| 508 | else if (errno != EAGAIN) |
| 509 | moan("accept: %s", strerror(errno)); |
| 510 | #endif |
| 511 | } |
| 512 | |
| 513 | for (cc = &clients; *cc;) { |
| 514 | c = *cc; |
| 515 | if (!FD_ISSET(c->fd, &fdin)) goto next_client; |
| 516 | n = read(c->fd, buf, sizeof(buf)); |
| 517 | if (!n) goto disconn; |
| 518 | else if (n < 0) { |
| 519 | if (errno == EAGAIN) goto next_client; |
| 520 | D( moan("read (client; auth): %s", strerror(errno)); ) |
| 521 | goto disconn; |
| 522 | } else { |
| 523 | for (p = buf, q = p + n; p < q; p++) { |
| 524 | switch (tokmatch_update(&c->tm, *p)) { |
| 525 | case 0: break; |
| 526 | case TF_FREEZE: goto connected; |
| 527 | default: |
| 528 | D( moan("bad token from client"); ) |
| 529 | goto disconn; |
| 530 | } |
| 531 | } |
| 532 | } |
| 533 | |
| 534 | next_client: |
| 535 | cc = &c->next; |
| 536 | continue; |
| 537 | |
| 538 | disconn: |
| 539 | close(c->fd); |
| 540 | *cc = c->next; |
| 541 | DESTROY(c); |
| 542 | continue; |
| 543 | } |
| 544 | } |
| 545 | |
| 546 | connected: |
| 547 | close(sk); sk = c->fd; |
| 548 | while (clients) { |
| 549 | if (clients->fd != sk) close(clients->fd); |
| 550 | c = clients->next; |
| 551 | DESTROY(clients); |
| 552 | clients = c; |
| 553 | } |
| 554 | |
| 555 | /* --- Establish signal handlers --- * |
| 556 | * |
| 557 | * Hopefully this will prevent bad things happening if we have an accident. |
| 558 | */ |
| 559 | |
| 560 | for (i = 0; i < N(sigcatch); i++) { |
| 561 | if (signal(sigcatch[i], sigmumble) == SIG_ERR) |
| 562 | die(2, "signal (%d): %s", i, strerror(errno)); |
| 563 | } |
| 564 | atexit(cleanup); |
| 565 | |
| 566 | /* --- Prevent the OOM killer from clobbering us --- */ |
| 567 | |
| 568 | if ((fd = open("/proc/self/oom_adj", O_WRONLY)) < 0 || |
| 569 | write(fd, "-17\n", 4) < 4 || |
| 570 | close(fd)) |
| 571 | die(2, "set oom_adj: %s", strerror(errno)); |
| 572 | |
| 573 | /* --- Actually freeze the filesystem --- */ |
| 574 | |
| 575 | for (i = 0; i < nfs; i++) { |
| 576 | if (fs[i] == -1) |
| 577 | moan("not really freezing %s", fsname[i]); |
| 578 | else { |
| 579 | if (ioctl(fs[i], FIFREEZE, 0) < 0) { |
| 580 | partial_cleanup(i); |
| 581 | die(2, "ioctl (freeze %s): %s", fsname[i], strerror(errno)); |
| 582 | } |
| 583 | } |
| 584 | } |
| 585 | if (writetok(T_FROZEN, sk)) { |
| 586 | cleanup(); |
| 587 | die(2, "write (frozen): %s", strerror(errno)); |
| 588 | } |
| 589 | |
| 590 | /* --- Now wait for the other end to detach --- */ |
| 591 | |
| 592 | tokmatch_init(&tm); |
| 593 | TV_ADDL(&when, &now, TO_KEEPALIVE, 0); |
| 594 | for (p++; p < q; p++) { |
| 595 | switch (tokmatch_update(&tm, *p)) { |
| 596 | case 0: break; |
| 597 | case TF_KEEPALIVE: tokmatch_init(&tm); break; |
| 598 | case TF_THAW: goto done; |
| 599 | default: cleanup(); die(3, "unknown token (keepalive)"); |
| 600 | } |
| 601 | } |
| 602 | for (;;) { |
| 603 | FD_ZERO(&fdin); |
| 604 | FD_SET(sk, &fdin); |
| 605 | TV_SUB(&delta, &when, &now); |
| 606 | if (select(sk + 1, &fdin, 0, 0, &delta) < 0) { |
| 607 | cleanup(); |
| 608 | die(2, "select (keepalive): %s", strerror(errno)); |
| 609 | } |
| 610 | |
| 611 | gettimeofday(&now, 0); |
| 612 | if (TV_CMP(&now, >, &when)) { |
| 613 | cleanup(); die(3, "timeout (keepalive)"); |
| 614 | } |
| 615 | if (FD_ISSET(sk, &fdin)) { |
| 616 | n = read(sk, buf, sizeof(buf)); |
| 617 | if (!n) { cleanup(); die(3, "end-of-file (keepalive)"); } |
| 618 | else if (n < 0) { |
| 619 | if (errno == EAGAIN) ; |
| 620 | else { |
| 621 | cleanup(); |
| 622 | die(2, "read (client, keepalive): %s", strerror(errno)); |
| 623 | } |
| 624 | } else { |
| 625 | for (p = buf, q = p + n; p < q; p++) { |
| 626 | switch (tokmatch_update(&tm, *p)) { |
| 627 | case 0: break; |
| 628 | case TF_KEEPALIVE: |
| 629 | TV_ADDL(&when, &now, TO_KEEPALIVE, 0); |
| 630 | tokmatch_init(&tm); |
| 631 | break; |
| 632 | case TF_THAW: |
| 633 | goto done; |
| 634 | default: |
| 635 | cleanup(); |
| 636 | die(3, "unknown token (keepalive)"); |
| 637 | } |
| 638 | } |
| 639 | } |
| 640 | } |
| 641 | } |
| 642 | |
| 643 | done: |
| 644 | cleanup(); |
| 645 | if (writetok(T_THAWED, sk)) |
| 646 | die(2, "write (thaw): %s", strerror(errno)); |
| 647 | close(sk); |
| 648 | return (0); |
| 649 | } |
| 650 | |
| 651 | /*----- That's all, folks -------------------------------------------------*/ |