1 /* $OpenBSD: client.c,v 1.150 2020/10/30 18:54:23 nicm Exp $ */ 2 3 /* 4 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER 15 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 16 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/socket.h> 21 #include <sys/uio.h> 22 #include <sys/un.h> 23 #include <sys/wait.h> 24 25 #include <errno.h> 26 #include <event.h> 27 #include <fcntl.h> 28 #include <imsg.h> 29 #include <signal.h> 30 #include <stdlib.h> 31 #include <string.h> 32 #include <unistd.h> 33 34 #include "tmux.h" 35 36 static struct tmuxproc *client_proc; 37 static struct tmuxpeer *client_peer; 38 static uint64_t client_flags; 39 static int client_suspended; 40 static enum { 41 CLIENT_EXIT_NONE, 42 CLIENT_EXIT_DETACHED, 43 CLIENT_EXIT_DETACHED_HUP, 44 CLIENT_EXIT_LOST_TTY, 45 CLIENT_EXIT_TERMINATED, 46 CLIENT_EXIT_LOST_SERVER, 47 CLIENT_EXIT_EXITED, 48 CLIENT_EXIT_SERVER_EXITED, 49 CLIENT_EXIT_MESSAGE_PROVIDED 50 } client_exitreason = CLIENT_EXIT_NONE; 51 static int client_exitflag; 52 static int client_exitval; 53 static enum msgtype client_exittype; 54 static const char *client_exitsession; 55 static char *client_exitmessage; 56 static const char *client_execshell; 57 static const char *client_execcmd; 58 static int client_attached; 59 static struct client_files client_files = RB_INITIALIZER(&client_files); 60 61 static __dead void client_exec(const char *,const char *); 62 static int client_get_lock(char *); 63 static int client_connect(struct event_base *, const char *, 64 uint64_t); 65 static void client_send_identify(const char *, const char *, int); 66 static void client_signal(int); 67 static void client_dispatch(struct imsg *, void *); 68 static void client_dispatch_attached(struct imsg *); 69 static void client_dispatch_wait(struct imsg *); 70 static const char *client_exit_message(void); 71 72 /* 73 * Get server create lock. If already held then server start is happening in 74 * another client, so block until the lock is released and return -2 to 75 * retry. Return -1 on failure to continue and start the server anyway. 76 */ 77 static int 78 client_get_lock(char *lockfile) 79 { 80 int lockfd; 81 82 log_debug("lock file is %s", lockfile); 83 84 if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1) { 85 log_debug("open failed: %s", strerror(errno)); 86 return (-1); 87 } 88 89 if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) { 90 log_debug("flock failed: %s", strerror(errno)); 91 if (errno != EAGAIN) 92 return (lockfd); 93 while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR) 94 /* nothing */; 95 close(lockfd); 96 return (-2); 97 } 98 log_debug("flock succeeded"); 99 100 return (lockfd); 101 } 102 103 /* Connect client to server. */ 104 static int 105 client_connect(struct event_base *base, const char *path, uint64_t flags) 106 { 107 struct sockaddr_un sa; 108 size_t size; 109 int fd, lockfd = -1, locked = 0; 110 char *lockfile = NULL; 111 112 memset(&sa, 0, sizeof sa); 113 sa.sun_family = AF_UNIX; 114 size = strlcpy(sa.sun_path, path, sizeof sa.sun_path); 115 if (size >= sizeof sa.sun_path) { 116 errno = ENAMETOOLONG; 117 return (-1); 118 } 119 log_debug("socket is %s", path); 120 121 retry: 122 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 123 return (-1); 124 125 log_debug("trying connect"); 126 if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 127 log_debug("connect failed: %s", strerror(errno)); 128 if (errno != ECONNREFUSED && errno != ENOENT) 129 goto failed; 130 if (~flags & CLIENT_STARTSERVER) 131 goto failed; 132 close(fd); 133 134 if (!locked) { 135 xasprintf(&lockfile, "%s.lock", path); 136 if ((lockfd = client_get_lock(lockfile)) < 0) { 137 log_debug("didn't get lock (%d)", lockfd); 138 139 free(lockfile); 140 lockfile = NULL; 141 142 if (lockfd == -2) 143 goto retry; 144 } 145 log_debug("got lock (%d)", lockfd); 146 147 /* 148 * Always retry at least once, even if we got the lock, 149 * because another client could have taken the lock, 150 * started the server and released the lock between our 151 * connect() and flock(). 152 */ 153 locked = 1; 154 goto retry; 155 } 156 157 if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) { 158 free(lockfile); 159 close(lockfd); 160 return (-1); 161 } 162 fd = server_start(client_proc, flags, base, lockfd, lockfile); 163 } 164 165 if (locked && lockfd >= 0) { 166 free(lockfile); 167 close(lockfd); 168 } 169 setblocking(fd, 0); 170 return (fd); 171 172 failed: 173 if (locked) { 174 free(lockfile); 175 close(lockfd); 176 } 177 close(fd); 178 return (-1); 179 } 180 181 /* Get exit string from reason number. */ 182 const char * 183 client_exit_message(void) 184 { 185 static char msg[256]; 186 187 switch (client_exitreason) { 188 case CLIENT_EXIT_NONE: 189 break; 190 case CLIENT_EXIT_DETACHED: 191 if (client_exitsession != NULL) { 192 xsnprintf(msg, sizeof msg, "detached " 193 "(from session %s)", client_exitsession); 194 return (msg); 195 } 196 return ("detached"); 197 case CLIENT_EXIT_DETACHED_HUP: 198 if (client_exitsession != NULL) { 199 xsnprintf(msg, sizeof msg, "detached and SIGHUP " 200 "(from session %s)", client_exitsession); 201 return (msg); 202 } 203 return ("detached and SIGHUP"); 204 case CLIENT_EXIT_LOST_TTY: 205 return ("lost tty"); 206 case CLIENT_EXIT_TERMINATED: 207 return ("terminated"); 208 case CLIENT_EXIT_LOST_SERVER: 209 return ("server exited unexpectedly"); 210 case CLIENT_EXIT_EXITED: 211 return ("exited"); 212 case CLIENT_EXIT_SERVER_EXITED: 213 return ("server exited"); 214 case CLIENT_EXIT_MESSAGE_PROVIDED: 215 return (client_exitmessage); 216 } 217 return ("unknown reason"); 218 } 219 220 /* Exit if all streams flushed. */ 221 static void 222 client_exit(void) 223 { 224 struct client_file *cf; 225 size_t left; 226 int waiting = 0; 227 228 RB_FOREACH (cf, client_files, &client_files) { 229 if (cf->event == NULL) 230 continue; 231 left = EVBUFFER_LENGTH(cf->event->output); 232 if (left != 0) { 233 waiting++; 234 log_debug("file %u %zu bytes left", cf->stream, left); 235 } 236 } 237 if (waiting == 0) 238 proc_exit(client_proc); 239 } 240 241 /* Client main loop. */ 242 int 243 client_main(struct event_base *base, int argc, char **argv, uint64_t flags, 244 int feat) 245 { 246 struct cmd_parse_result *pr; 247 struct msg_command *data; 248 int fd, i; 249 const char *ttynam, *cwd; 250 pid_t ppid; 251 enum msgtype msg; 252 struct termios tio, saved_tio; 253 size_t size, linesize = 0; 254 ssize_t linelen; 255 char *line = NULL; 256 257 /* Ignore SIGCHLD now or daemon() in the server will leave a zombie. */ 258 signal(SIGCHLD, SIG_IGN); 259 260 /* Set up the initial command. */ 261 if (shell_command != NULL) { 262 msg = MSG_SHELL; 263 flags |= CLIENT_STARTSERVER; 264 } else if (argc == 0) { 265 msg = MSG_COMMAND; 266 flags |= CLIENT_STARTSERVER; 267 } else { 268 msg = MSG_COMMAND; 269 270 /* 271 * It sucks parsing the command string twice (in client and 272 * later in server) but it is necessary to get the start server 273 * flag. 274 */ 275 pr = cmd_parse_from_arguments(argc, argv, NULL); 276 if (pr->status == CMD_PARSE_SUCCESS) { 277 if (cmd_list_any_have(pr->cmdlist, CMD_STARTSERVER)) 278 flags |= CLIENT_STARTSERVER; 279 cmd_list_free(pr->cmdlist); 280 } else 281 free(pr->error); 282 } 283 284 /* Create client process structure (starts logging). */ 285 client_proc = proc_start("client"); 286 proc_set_signals(client_proc, client_signal); 287 288 /* Save the flags. */ 289 client_flags = flags; 290 log_debug("flags are %#llx", (unsigned long long)client_flags); 291 292 /* Initialize the client socket and start the server. */ 293 fd = client_connect(base, socket_path, client_flags); 294 if (fd == -1) { 295 if (errno == ECONNREFUSED) { 296 fprintf(stderr, "no server running on %s\n", 297 socket_path); 298 } else { 299 fprintf(stderr, "error connecting to %s (%s)\n", 300 socket_path, strerror(errno)); 301 } 302 return (1); 303 } 304 client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL); 305 306 /* Save these before pledge(). */ 307 if ((cwd = find_cwd()) == NULL && (cwd = find_home()) == NULL) 308 cwd = "/"; 309 if ((ttynam = ttyname(STDIN_FILENO)) == NULL) 310 ttynam = ""; 311 312 /* 313 * Drop privileges for client. "proc exec" is needed for -c and for 314 * locking (which uses system(3)). 315 * 316 * "tty" is needed to restore termios(4) and also for some reason -CC 317 * does not work properly without it (input is not recognised). 318 * 319 * "sendfd" is dropped later in client_dispatch_wait(). 320 */ 321 if (pledge( 322 "stdio rpath wpath cpath unix sendfd proc exec tty", 323 NULL) != 0) 324 fatal("pledge failed"); 325 326 /* Free stuff that is not used in the client. */ 327 if (ptm_fd != -1) 328 close(ptm_fd); 329 options_free(global_options); 330 options_free(global_s_options); 331 options_free(global_w_options); 332 environ_free(global_environ); 333 334 /* Set up control mode. */ 335 if (client_flags & CLIENT_CONTROLCONTROL) { 336 if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) { 337 fprintf(stderr, "tcgetattr failed: %s\n", 338 strerror(errno)); 339 return (1); 340 } 341 cfmakeraw(&tio); 342 tio.c_iflag = ICRNL|IXANY; 343 tio.c_oflag = OPOST|ONLCR; 344 tio.c_lflag = NOKERNINFO; 345 tio.c_cflag = CREAD|CS8|HUPCL; 346 tio.c_cc[VMIN] = 1; 347 tio.c_cc[VTIME] = 0; 348 cfsetispeed(&tio, cfgetispeed(&saved_tio)); 349 cfsetospeed(&tio, cfgetospeed(&saved_tio)); 350 tcsetattr(STDIN_FILENO, TCSANOW, &tio); 351 } 352 353 /* Send identify messages. */ 354 client_send_identify(ttynam, cwd, feat); 355 356 /* Send first command. */ 357 if (msg == MSG_COMMAND) { 358 /* How big is the command? */ 359 size = 0; 360 for (i = 0; i < argc; i++) 361 size += strlen(argv[i]) + 1; 362 if (size > MAX_IMSGSIZE - (sizeof *data)) { 363 fprintf(stderr, "command too long\n"); 364 return (1); 365 } 366 data = xmalloc((sizeof *data) + size); 367 368 /* Prepare command for server. */ 369 data->argc = argc; 370 if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) { 371 fprintf(stderr, "command too long\n"); 372 free(data); 373 return (1); 374 } 375 size += sizeof *data; 376 377 /* Send the command. */ 378 if (proc_send(client_peer, msg, -1, data, size) != 0) { 379 fprintf(stderr, "failed to send command\n"); 380 free(data); 381 return (1); 382 } 383 free(data); 384 } else if (msg == MSG_SHELL) 385 proc_send(client_peer, msg, -1, NULL, 0); 386 387 /* Start main loop. */ 388 proc_loop(client_proc, NULL); 389 390 /* Run command if user requested exec, instead of exiting. */ 391 if (client_exittype == MSG_EXEC) { 392 if (client_flags & CLIENT_CONTROLCONTROL) 393 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 394 client_exec(client_execshell, client_execcmd); 395 } 396 397 /* Restore streams to blocking. */ 398 setblocking(STDIN_FILENO, 1); 399 setblocking(STDOUT_FILENO, 1); 400 setblocking(STDERR_FILENO, 1); 401 402 /* Print the exit message, if any, and exit. */ 403 if (client_attached) { 404 if (client_exitreason != CLIENT_EXIT_NONE) 405 printf("[%s]\n", client_exit_message()); 406 407 ppid = getppid(); 408 if (client_exittype == MSG_DETACHKILL && ppid > 1) 409 kill(ppid, SIGHUP); 410 } else if (client_flags & CLIENT_CONTROL) { 411 if (client_exitreason != CLIENT_EXIT_NONE) 412 printf("%%exit %s\n", client_exit_message()); 413 else 414 printf("%%exit\n"); 415 fflush(stdout); 416 if (client_flags & CLIENT_CONTROL_WAITEXIT) { 417 setvbuf(stdin, NULL, _IOLBF, 0); 418 for (;;) { 419 linelen = getline(&line, &linesize, stdin); 420 if (linelen <= 1) 421 break; 422 } 423 free(line); 424 } 425 if (client_flags & CLIENT_CONTROLCONTROL) { 426 printf("\033\\"); 427 fflush(stdout); 428 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 429 } 430 } else if (client_exitreason != CLIENT_EXIT_NONE) 431 fprintf(stderr, "%s\n", client_exit_message()); 432 return (client_exitval); 433 } 434 435 /* Send identify messages to server. */ 436 static void 437 client_send_identify(const char *ttynam, const char *cwd, int feat) 438 { 439 const char *s; 440 char **ss; 441 size_t sslen; 442 int fd, flags = client_flags; 443 pid_t pid; 444 445 proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags); 446 proc_send(client_peer, MSG_IDENTIFY_LONGFLAGS, -1, &client_flags, 447 sizeof client_flags); 448 449 if ((s = getenv("TERM")) == NULL) 450 s = ""; 451 proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1); 452 proc_send(client_peer, MSG_IDENTIFY_FEATURES, -1, &feat, sizeof feat); 453 454 proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam, 455 strlen(ttynam) + 1); 456 proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1); 457 458 if ((fd = dup(STDIN_FILENO)) == -1) 459 fatal("dup failed"); 460 proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0); 461 if ((fd = dup(STDOUT_FILENO)) == -1) 462 fatal("dup failed"); 463 proc_send(client_peer, MSG_IDENTIFY_STDOUT, fd, NULL, 0); 464 465 pid = getpid(); 466 proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid); 467 468 for (ss = environ; *ss != NULL; ss++) { 469 sslen = strlen(*ss) + 1; 470 if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE) 471 continue; 472 proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen); 473 } 474 475 proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0); 476 } 477 478 /* File write error callback. */ 479 static void 480 client_write_error_callback(__unused struct bufferevent *bev, 481 __unused short what, void *arg) 482 { 483 struct client_file *cf = arg; 484 485 log_debug("write error file %d", cf->stream); 486 487 bufferevent_free(cf->event); 488 cf->event = NULL; 489 490 close(cf->fd); 491 cf->fd = -1; 492 493 if (client_exitflag) 494 client_exit(); 495 } 496 497 /* File write callback. */ 498 static void 499 client_write_callback(__unused struct bufferevent *bev, void *arg) 500 { 501 struct client_file *cf = arg; 502 503 if (cf->closed && EVBUFFER_LENGTH(cf->event->output) == 0) { 504 bufferevent_free(cf->event); 505 close(cf->fd); 506 RB_REMOVE(client_files, &client_files, cf); 507 file_free(cf); 508 } 509 510 if (client_exitflag) 511 client_exit(); 512 } 513 514 /* Open write file. */ 515 static void 516 client_write_open(void *data, size_t datalen) 517 { 518 struct msg_write_open *msg = data; 519 const char *path; 520 struct msg_write_ready reply; 521 struct client_file find, *cf; 522 const int flags = O_NONBLOCK|O_WRONLY|O_CREAT; 523 int error = 0; 524 525 if (datalen < sizeof *msg) 526 fatalx("bad MSG_WRITE_OPEN size"); 527 if (datalen == sizeof *msg) 528 path = "-"; 529 else 530 path = (const char *)(msg + 1); 531 log_debug("open write file %d %s", msg->stream, path); 532 533 find.stream = msg->stream; 534 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 535 cf = file_create(NULL, msg->stream, NULL, NULL); 536 RB_INSERT(client_files, &client_files, cf); 537 } else { 538 error = EBADF; 539 goto reply; 540 } 541 if (cf->closed) { 542 error = EBADF; 543 goto reply; 544 } 545 546 cf->fd = -1; 547 if (msg->fd == -1) 548 cf->fd = open(path, msg->flags|flags, 0644); 549 else { 550 if (msg->fd != STDOUT_FILENO && msg->fd != STDERR_FILENO) 551 errno = EBADF; 552 else { 553 cf->fd = dup(msg->fd); 554 if (~client_flags & CLIENT_CONTROL) 555 close(msg->fd); /* can only be used once */ 556 } 557 } 558 if (cf->fd == -1) { 559 error = errno; 560 goto reply; 561 } 562 563 cf->event = bufferevent_new(cf->fd, NULL, client_write_callback, 564 client_write_error_callback, cf); 565 bufferevent_enable(cf->event, EV_WRITE); 566 goto reply; 567 568 reply: 569 reply.stream = msg->stream; 570 reply.error = error; 571 proc_send(client_peer, MSG_WRITE_READY, -1, &reply, sizeof reply); 572 } 573 574 /* Write to client file. */ 575 static void 576 client_write_data(void *data, size_t datalen) 577 { 578 struct msg_write_data *msg = data; 579 struct client_file find, *cf; 580 size_t size = datalen - sizeof *msg; 581 582 if (datalen < sizeof *msg) 583 fatalx("bad MSG_WRITE size"); 584 find.stream = msg->stream; 585 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 586 fatalx("unknown stream number"); 587 log_debug("write %zu to file %d", size, cf->stream); 588 589 if (cf->event != NULL) 590 bufferevent_write(cf->event, msg + 1, size); 591 } 592 593 /* Close client file. */ 594 static void 595 client_write_close(void *data, size_t datalen) 596 { 597 struct msg_write_close *msg = data; 598 struct client_file find, *cf; 599 600 if (datalen != sizeof *msg) 601 fatalx("bad MSG_WRITE_CLOSE size"); 602 find.stream = msg->stream; 603 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 604 fatalx("unknown stream number"); 605 log_debug("close file %d", cf->stream); 606 607 if (cf->event == NULL || EVBUFFER_LENGTH(cf->event->output) == 0) { 608 if (cf->event != NULL) 609 bufferevent_free(cf->event); 610 if (cf->fd != -1) 611 close(cf->fd); 612 RB_REMOVE(client_files, &client_files, cf); 613 file_free(cf); 614 } 615 } 616 617 /* File read callback. */ 618 static void 619 client_read_callback(__unused struct bufferevent *bev, void *arg) 620 { 621 struct client_file *cf = arg; 622 void *bdata; 623 size_t bsize; 624 struct msg_read_data *msg; 625 size_t msglen; 626 627 msg = xmalloc(sizeof *msg); 628 for (;;) { 629 bdata = EVBUFFER_DATA(cf->event->input); 630 bsize = EVBUFFER_LENGTH(cf->event->input); 631 632 if (bsize == 0) 633 break; 634 if (bsize > MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg) 635 bsize = MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg; 636 log_debug("read %zu from file %d", bsize, cf->stream); 637 638 msglen = (sizeof *msg) + bsize; 639 msg = xrealloc(msg, msglen); 640 msg->stream = cf->stream; 641 memcpy(msg + 1, bdata, bsize); 642 proc_send(client_peer, MSG_READ, -1, msg, msglen); 643 644 evbuffer_drain(cf->event->input, bsize); 645 } 646 free(msg); 647 } 648 649 /* File read error callback. */ 650 static void 651 client_read_error_callback(__unused struct bufferevent *bev, 652 __unused short what, void *arg) 653 { 654 struct client_file *cf = arg; 655 struct msg_read_done msg; 656 657 log_debug("read error file %d", cf->stream); 658 659 msg.stream = cf->stream; 660 msg.error = 0; 661 proc_send(client_peer, MSG_READ_DONE, -1, &msg, sizeof msg); 662 663 bufferevent_free(cf->event); 664 close(cf->fd); 665 RB_REMOVE(client_files, &client_files, cf); 666 file_free(cf); 667 } 668 669 /* Open read file. */ 670 static void 671 client_read_open(void *data, size_t datalen) 672 { 673 struct msg_read_open *msg = data; 674 const char *path; 675 struct msg_read_done reply; 676 struct client_file find, *cf; 677 const int flags = O_NONBLOCK|O_RDONLY; 678 int error; 679 680 if (datalen < sizeof *msg) 681 fatalx("bad MSG_READ_OPEN size"); 682 if (datalen == sizeof *msg) 683 path = "-"; 684 else 685 path = (const char *)(msg + 1); 686 log_debug("open read file %d %s", msg->stream, path); 687 688 find.stream = msg->stream; 689 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 690 cf = file_create(NULL, msg->stream, NULL, NULL); 691 RB_INSERT(client_files, &client_files, cf); 692 } else { 693 error = EBADF; 694 goto reply; 695 } 696 if (cf->closed) { 697 error = EBADF; 698 goto reply; 699 } 700 701 cf->fd = -1; 702 if (msg->fd == -1) 703 cf->fd = open(path, flags); 704 else { 705 if (msg->fd != STDIN_FILENO) 706 errno = EBADF; 707 else { 708 cf->fd = dup(msg->fd); 709 if (~client_flags & CLIENT_CONTROL) 710 close(msg->fd); /* can only be used once */ 711 } 712 } 713 if (cf->fd == -1) { 714 error = errno; 715 goto reply; 716 } 717 718 cf->event = bufferevent_new(cf->fd, client_read_callback, NULL, 719 client_read_error_callback, cf); 720 bufferevent_enable(cf->event, EV_READ); 721 return; 722 723 reply: 724 reply.stream = msg->stream; 725 reply.error = error; 726 proc_send(client_peer, MSG_READ_DONE, -1, &reply, sizeof reply); 727 } 728 729 /* Run command in shell; used for -c. */ 730 static __dead void 731 client_exec(const char *shell, const char *shellcmd) 732 { 733 const char *name, *ptr; 734 char *argv0; 735 736 log_debug("shell %s, command %s", shell, shellcmd); 737 738 ptr = strrchr(shell, '/'); 739 if (ptr != NULL && *(ptr + 1) != '\0') 740 name = ptr + 1; 741 else 742 name = shell; 743 if (client_flags & CLIENT_LOGIN) 744 xasprintf(&argv0, "-%s", name); 745 else 746 xasprintf(&argv0, "%s", name); 747 setenv("SHELL", shell, 1); 748 749 proc_clear_signals(client_proc, 1); 750 751 setblocking(STDIN_FILENO, 1); 752 setblocking(STDOUT_FILENO, 1); 753 setblocking(STDERR_FILENO, 1); 754 closefrom(STDERR_FILENO + 1); 755 756 execl(shell, argv0, "-c", shellcmd, (char *) NULL); 757 fatal("execl failed"); 758 } 759 760 /* Callback to handle signals in the client. */ 761 static void 762 client_signal(int sig) 763 { 764 struct sigaction sigact; 765 int status; 766 767 log_debug("%s: %s", __func__, strsignal(sig)); 768 if (sig == SIGCHLD) 769 waitpid(WAIT_ANY, &status, WNOHANG); 770 else if (!client_attached) { 771 if (sig == SIGTERM) 772 proc_exit(client_proc); 773 } else { 774 switch (sig) { 775 case SIGHUP: 776 client_exitreason = CLIENT_EXIT_LOST_TTY; 777 client_exitval = 1; 778 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 779 break; 780 case SIGTERM: 781 if (!client_suspended) 782 client_exitreason = CLIENT_EXIT_TERMINATED; 783 client_exitval = 1; 784 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 785 break; 786 case SIGWINCH: 787 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 788 break; 789 case SIGCONT: 790 memset(&sigact, 0, sizeof sigact); 791 sigemptyset(&sigact.sa_mask); 792 sigact.sa_flags = SA_RESTART; 793 sigact.sa_handler = SIG_IGN; 794 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 795 fatal("sigaction failed"); 796 proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0); 797 client_suspended = 0; 798 break; 799 } 800 } 801 } 802 803 /* Callback for client read events. */ 804 static void 805 client_dispatch(struct imsg *imsg, __unused void *arg) 806 { 807 if (imsg == NULL) { 808 client_exitreason = CLIENT_EXIT_LOST_SERVER; 809 client_exitval = 1; 810 proc_exit(client_proc); 811 return; 812 } 813 814 if (client_attached) 815 client_dispatch_attached(imsg); 816 else 817 client_dispatch_wait(imsg); 818 } 819 820 /* Process an exit message. */ 821 static void 822 client_dispatch_exit_message(char *data, size_t datalen) 823 { 824 int retval; 825 826 if (datalen < sizeof retval && datalen != 0) 827 fatalx("bad MSG_EXIT size"); 828 829 if (datalen >= sizeof retval) { 830 memcpy(&retval, data, sizeof retval); 831 client_exitval = retval; 832 } 833 834 if (datalen > sizeof retval) { 835 datalen -= sizeof retval; 836 data += sizeof retval; 837 838 client_exitmessage = xmalloc(datalen); 839 memcpy(client_exitmessage, data, datalen); 840 client_exitmessage[datalen - 1] = '\0'; 841 842 client_exitreason = CLIENT_EXIT_MESSAGE_PROVIDED; 843 } 844 } 845 846 /* Dispatch imsgs when in wait state (before MSG_READY). */ 847 static void 848 client_dispatch_wait(struct imsg *imsg) 849 { 850 char *data; 851 ssize_t datalen; 852 static int pledge_applied; 853 854 /* 855 * "sendfd" is no longer required once all of the identify messages 856 * have been sent. We know the server won't send us anything until that 857 * point (because we don't ask it to), so we can drop "sendfd" once we 858 * get the first message from the server. 859 */ 860 if (!pledge_applied) { 861 if (pledge( 862 "stdio rpath wpath cpath unix proc exec tty", 863 NULL) != 0) 864 fatal("pledge failed"); 865 pledge_applied = 1; 866 } 867 868 data = imsg->data; 869 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 870 871 switch (imsg->hdr.type) { 872 case MSG_EXIT: 873 case MSG_SHUTDOWN: 874 client_dispatch_exit_message(data, datalen); 875 client_exitflag = 1; 876 client_exit(); 877 break; 878 case MSG_READY: 879 if (datalen != 0) 880 fatalx("bad MSG_READY size"); 881 882 client_attached = 1; 883 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 884 break; 885 case MSG_VERSION: 886 if (datalen != 0) 887 fatalx("bad MSG_VERSION size"); 888 889 fprintf(stderr, "protocol version mismatch " 890 "(client %d, server %u)\n", PROTOCOL_VERSION, 891 imsg->hdr.peerid & 0xff); 892 client_exitval = 1; 893 proc_exit(client_proc); 894 break; 895 case MSG_FLAGS: 896 if (datalen != sizeof client_flags) 897 fatalx("bad MSG_FLAGS string"); 898 899 memcpy(&client_flags, data, sizeof client_flags); 900 log_debug("new flags are %#llx", 901 (unsigned long long)client_flags); 902 break; 903 case MSG_SHELL: 904 if (datalen == 0 || data[datalen - 1] != '\0') 905 fatalx("bad MSG_SHELL string"); 906 907 client_exec(data, shell_command); 908 /* NOTREACHED */ 909 case MSG_DETACH: 910 case MSG_DETACHKILL: 911 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 912 break; 913 case MSG_EXITED: 914 proc_exit(client_proc); 915 break; 916 case MSG_READ_OPEN: 917 client_read_open(data, datalen); 918 break; 919 case MSG_WRITE_OPEN: 920 client_write_open(data, datalen); 921 break; 922 case MSG_WRITE: 923 client_write_data(data, datalen); 924 break; 925 case MSG_WRITE_CLOSE: 926 client_write_close(data, datalen); 927 break; 928 case MSG_OLDSTDERR: 929 case MSG_OLDSTDIN: 930 case MSG_OLDSTDOUT: 931 fprintf(stderr, "server version is too old for client\n"); 932 proc_exit(client_proc); 933 break; 934 } 935 } 936 937 /* Dispatch imsgs in attached state (after MSG_READY). */ 938 static void 939 client_dispatch_attached(struct imsg *imsg) 940 { 941 struct sigaction sigact; 942 char *data; 943 ssize_t datalen; 944 945 data = imsg->data; 946 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 947 948 switch (imsg->hdr.type) { 949 case MSG_FLAGS: 950 if (datalen != sizeof client_flags) 951 fatalx("bad MSG_FLAGS string"); 952 953 memcpy(&client_flags, data, sizeof client_flags); 954 log_debug("new flags are %#llx", 955 (unsigned long long)client_flags); 956 break; 957 case MSG_DETACH: 958 case MSG_DETACHKILL: 959 if (datalen == 0 || data[datalen - 1] != '\0') 960 fatalx("bad MSG_DETACH string"); 961 962 client_exitsession = xstrdup(data); 963 client_exittype = imsg->hdr.type; 964 if (imsg->hdr.type == MSG_DETACHKILL) 965 client_exitreason = CLIENT_EXIT_DETACHED_HUP; 966 else 967 client_exitreason = CLIENT_EXIT_DETACHED; 968 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 969 break; 970 case MSG_EXEC: 971 if (datalen == 0 || data[datalen - 1] != '\0' || 972 strlen(data) + 1 == (size_t)datalen) 973 fatalx("bad MSG_EXEC string"); 974 client_execcmd = xstrdup(data); 975 client_execshell = xstrdup(data + strlen(data) + 1); 976 977 client_exittype = imsg->hdr.type; 978 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 979 break; 980 case MSG_EXIT: 981 client_dispatch_exit_message(data, datalen); 982 if (client_exitreason == CLIENT_EXIT_NONE) 983 client_exitreason = CLIENT_EXIT_EXITED; 984 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 985 break; 986 case MSG_EXITED: 987 if (datalen != 0) 988 fatalx("bad MSG_EXITED size"); 989 990 proc_exit(client_proc); 991 break; 992 case MSG_SHUTDOWN: 993 if (datalen != 0) 994 fatalx("bad MSG_SHUTDOWN size"); 995 996 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 997 client_exitreason = CLIENT_EXIT_SERVER_EXITED; 998 client_exitval = 1; 999 break; 1000 case MSG_SUSPEND: 1001 if (datalen != 0) 1002 fatalx("bad MSG_SUSPEND size"); 1003 1004 memset(&sigact, 0, sizeof sigact); 1005 sigemptyset(&sigact.sa_mask); 1006 sigact.sa_flags = SA_RESTART; 1007 sigact.sa_handler = SIG_DFL; 1008 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 1009 fatal("sigaction failed"); 1010 client_suspended = 1; 1011 kill(getpid(), SIGTSTP); 1012 break; 1013 case MSG_LOCK: 1014 if (datalen == 0 || data[datalen - 1] != '\0') 1015 fatalx("bad MSG_LOCK string"); 1016 1017 system(data); 1018 proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0); 1019 break; 1020 } 1021 } 1022