1 /* $OpenBSD: client.c,v 1.137 2020/01/29 16:22:32 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/un.h> 22 #include <sys/wait.h> 23 24 #include <errno.h> 25 #include <event.h> 26 #include <fcntl.h> 27 #include <imsg.h> 28 #include <signal.h> 29 #include <stdlib.h> 30 #include <string.h> 31 #include <unistd.h> 32 33 #include "tmux.h" 34 35 static struct tmuxproc *client_proc; 36 static struct tmuxpeer *client_peer; 37 static int client_flags; 38 static enum { 39 CLIENT_EXIT_NONE, 40 CLIENT_EXIT_DETACHED, 41 CLIENT_EXIT_DETACHED_HUP, 42 CLIENT_EXIT_LOST_TTY, 43 CLIENT_EXIT_TERMINATED, 44 CLIENT_EXIT_LOST_SERVER, 45 CLIENT_EXIT_EXITED, 46 CLIENT_EXIT_SERVER_EXITED, 47 } client_exitreason = CLIENT_EXIT_NONE; 48 static int client_exitflag; 49 static int client_exitval; 50 static enum msgtype client_exittype; 51 static const char *client_exitsession; 52 static const char *client_execshell; 53 static const char *client_execcmd; 54 static int client_attached; 55 static struct client_files client_files = RB_INITIALIZER(&client_files); 56 57 static __dead void client_exec(const char *,const char *); 58 static int client_get_lock(char *); 59 static int client_connect(struct event_base *, const char *, int); 60 static void client_send_identify(const char *, const char *); 61 static void client_signal(int); 62 static void client_dispatch(struct imsg *, void *); 63 static void client_dispatch_attached(struct imsg *); 64 static void client_dispatch_wait(struct imsg *); 65 static const char *client_exit_message(void); 66 67 /* 68 * Get server create lock. If already held then server start is happening in 69 * another client, so block until the lock is released and return -2 to 70 * retry. Return -1 on failure to continue and start the server anyway. 71 */ 72 static int 73 client_get_lock(char *lockfile) 74 { 75 int lockfd; 76 77 log_debug("lock file is %s", lockfile); 78 79 if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1) { 80 log_debug("open failed: %s", strerror(errno)); 81 return (-1); 82 } 83 84 if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) { 85 log_debug("flock failed: %s", strerror(errno)); 86 if (errno != EAGAIN) 87 return (lockfd); 88 while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR) 89 /* nothing */; 90 close(lockfd); 91 return (-2); 92 } 93 log_debug("flock succeeded"); 94 95 return (lockfd); 96 } 97 98 /* Connect client to server. */ 99 static int 100 client_connect(struct event_base *base, const char *path, int start_server) 101 { 102 struct sockaddr_un sa; 103 size_t size; 104 int fd, lockfd = -1, locked = 0; 105 char *lockfile = NULL; 106 107 memset(&sa, 0, sizeof sa); 108 sa.sun_family = AF_UNIX; 109 size = strlcpy(sa.sun_path, path, sizeof sa.sun_path); 110 if (size >= sizeof sa.sun_path) { 111 errno = ENAMETOOLONG; 112 return (-1); 113 } 114 log_debug("socket is %s", path); 115 116 retry: 117 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 118 return (-1); 119 120 log_debug("trying connect"); 121 if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 122 log_debug("connect failed: %s", strerror(errno)); 123 if (errno != ECONNREFUSED && errno != ENOENT) 124 goto failed; 125 if (!start_server) 126 goto failed; 127 close(fd); 128 129 if (!locked) { 130 xasprintf(&lockfile, "%s.lock", path); 131 if ((lockfd = client_get_lock(lockfile)) < 0) { 132 log_debug("didn't get lock (%d)", lockfd); 133 134 free(lockfile); 135 lockfile = NULL; 136 137 if (lockfd == -2) 138 goto retry; 139 } 140 log_debug("got lock (%d)", lockfd); 141 142 /* 143 * Always retry at least once, even if we got the lock, 144 * because another client could have taken the lock, 145 * started the server and released the lock between our 146 * connect() and flock(). 147 */ 148 locked = 1; 149 goto retry; 150 } 151 152 if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) { 153 free(lockfile); 154 close(lockfd); 155 return (-1); 156 } 157 fd = server_start(client_proc, base, lockfd, lockfile); 158 } 159 160 if (locked && lockfd >= 0) { 161 free(lockfile); 162 close(lockfd); 163 } 164 setblocking(fd, 0); 165 return (fd); 166 167 failed: 168 if (locked) { 169 free(lockfile); 170 close(lockfd); 171 } 172 close(fd); 173 return (-1); 174 } 175 176 /* Get exit string from reason number. */ 177 const char * 178 client_exit_message(void) 179 { 180 static char msg[256]; 181 182 switch (client_exitreason) { 183 case CLIENT_EXIT_NONE: 184 break; 185 case CLIENT_EXIT_DETACHED: 186 if (client_exitsession != NULL) { 187 xsnprintf(msg, sizeof msg, "detached " 188 "(from session %s)", client_exitsession); 189 return (msg); 190 } 191 return ("detached"); 192 case CLIENT_EXIT_DETACHED_HUP: 193 if (client_exitsession != NULL) { 194 xsnprintf(msg, sizeof msg, "detached and SIGHUP " 195 "(from session %s)", client_exitsession); 196 return (msg); 197 } 198 return ("detached and SIGHUP"); 199 case CLIENT_EXIT_LOST_TTY: 200 return ("lost tty"); 201 case CLIENT_EXIT_TERMINATED: 202 return ("terminated"); 203 case CLIENT_EXIT_LOST_SERVER: 204 return ("server exited unexpectedly"); 205 case CLIENT_EXIT_EXITED: 206 return ("exited"); 207 case CLIENT_EXIT_SERVER_EXITED: 208 return ("server exited"); 209 } 210 return ("unknown reason"); 211 } 212 213 /* Exit if all streams flushed. */ 214 static void 215 client_exit(void) 216 { 217 struct client_file *cf; 218 size_t left; 219 int waiting = 0; 220 221 RB_FOREACH (cf, client_files, &client_files) { 222 if (cf->event == NULL) 223 continue; 224 left = EVBUFFER_LENGTH(cf->event->output); 225 if (left != 0) { 226 waiting++; 227 log_debug("file %u %zu bytes left", cf->stream, left); 228 } 229 } 230 if (waiting == 0) 231 proc_exit(client_proc); 232 } 233 234 /* Client main loop. */ 235 int 236 client_main(struct event_base *base, int argc, char **argv, int flags) 237 { 238 struct cmd_parse_result *pr; 239 struct cmd *cmd; 240 struct msg_command *data; 241 int cmdflags, fd, i; 242 const char *ttynam, *cwd; 243 pid_t ppid; 244 enum msgtype msg; 245 struct termios tio, saved_tio; 246 size_t size; 247 248 /* Ignore SIGCHLD now or daemon() in the server will leave a zombie. */ 249 signal(SIGCHLD, SIG_IGN); 250 251 /* Save the flags. */ 252 client_flags = flags; 253 254 /* Set up the initial command. */ 255 cmdflags = 0; 256 if (shell_command != NULL) { 257 msg = MSG_SHELL; 258 cmdflags = CMD_STARTSERVER; 259 } else if (argc == 0) { 260 msg = MSG_COMMAND; 261 cmdflags = CMD_STARTSERVER; 262 } else { 263 msg = MSG_COMMAND; 264 265 /* 266 * It sucks parsing the command string twice (in client and 267 * later in server) but it is necessary to get the start server 268 * flag. 269 */ 270 pr = cmd_parse_from_arguments(argc, argv, NULL); 271 if (pr->status == CMD_PARSE_SUCCESS) { 272 TAILQ_FOREACH(cmd, &pr->cmdlist->list, qentry) { 273 if (cmd->entry->flags & CMD_STARTSERVER) 274 cmdflags |= CMD_STARTSERVER; 275 } 276 cmd_list_free(pr->cmdlist); 277 } else 278 free(pr->error); 279 } 280 281 /* Create client process structure (starts logging). */ 282 client_proc = proc_start("client"); 283 proc_set_signals(client_proc, client_signal); 284 285 /* Initialize the client socket and start the server. */ 286 fd = client_connect(base, socket_path, cmdflags & CMD_STARTSERVER); 287 if (fd == -1) { 288 if (errno == ECONNREFUSED) { 289 fprintf(stderr, "no server running on %s\n", 290 socket_path); 291 } else { 292 fprintf(stderr, "error connecting to %s (%s)\n", 293 socket_path, strerror(errno)); 294 } 295 return (1); 296 } 297 client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL); 298 299 /* Save these before pledge(). */ 300 if ((cwd = find_cwd()) == NULL && (cwd = find_home()) == NULL) 301 cwd = "/"; 302 if ((ttynam = ttyname(STDIN_FILENO)) == NULL) 303 ttynam = ""; 304 305 /* 306 * Drop privileges for client. "proc exec" is needed for -c and for 307 * locking (which uses system(3)). 308 * 309 * "tty" is needed to restore termios(4) and also for some reason -CC 310 * does not work properly without it (input is not recognised). 311 * 312 * "sendfd" is dropped later in client_dispatch_wait(). 313 */ 314 if (pledge( 315 "stdio rpath wpath cpath unix sendfd proc exec tty", 316 NULL) != 0) 317 fatal("pledge failed"); 318 319 /* Free stuff that is not used in the client. */ 320 if (ptm_fd != -1) 321 close(ptm_fd); 322 options_free(global_options); 323 options_free(global_s_options); 324 options_free(global_w_options); 325 environ_free(global_environ); 326 327 /* Set up control mode. */ 328 if (client_flags & CLIENT_CONTROLCONTROL) { 329 if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) { 330 fprintf(stderr, "tcgetattr failed: %s\n", 331 strerror(errno)); 332 return (1); 333 } 334 cfmakeraw(&tio); 335 tio.c_iflag = ICRNL|IXANY; 336 tio.c_oflag = OPOST|ONLCR; 337 tio.c_lflag = NOKERNINFO; 338 tio.c_cflag = CREAD|CS8|HUPCL; 339 tio.c_cc[VMIN] = 1; 340 tio.c_cc[VTIME] = 0; 341 cfsetispeed(&tio, cfgetispeed(&saved_tio)); 342 cfsetospeed(&tio, cfgetospeed(&saved_tio)); 343 tcsetattr(STDIN_FILENO, TCSANOW, &tio); 344 } 345 346 /* Send identify messages. */ 347 client_send_identify(ttynam, cwd); 348 349 /* Send first command. */ 350 if (msg == MSG_COMMAND) { 351 /* How big is the command? */ 352 size = 0; 353 for (i = 0; i < argc; i++) 354 size += strlen(argv[i]) + 1; 355 if (size > MAX_IMSGSIZE - (sizeof *data)) { 356 fprintf(stderr, "command too long\n"); 357 return (1); 358 } 359 data = xmalloc((sizeof *data) + size); 360 361 /* Prepare command for server. */ 362 data->argc = argc; 363 if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) { 364 fprintf(stderr, "command too long\n"); 365 free(data); 366 return (1); 367 } 368 size += sizeof *data; 369 370 /* Send the command. */ 371 if (proc_send(client_peer, msg, -1, data, size) != 0) { 372 fprintf(stderr, "failed to send command\n"); 373 free(data); 374 return (1); 375 } 376 free(data); 377 } else if (msg == MSG_SHELL) 378 proc_send(client_peer, msg, -1, NULL, 0); 379 380 /* Start main loop. */ 381 proc_loop(client_proc, NULL); 382 383 /* Run command if user requested exec, instead of exiting. */ 384 if (client_exittype == MSG_EXEC) { 385 if (client_flags & CLIENT_CONTROLCONTROL) 386 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 387 client_exec(client_execshell, client_execcmd); 388 } 389 390 /* Print the exit message, if any, and exit. */ 391 if (client_attached) { 392 if (client_exitreason != CLIENT_EXIT_NONE) 393 printf("[%s]\n", client_exit_message()); 394 395 ppid = getppid(); 396 if (client_exittype == MSG_DETACHKILL && ppid > 1) 397 kill(ppid, SIGHUP); 398 } else if (client_flags & CLIENT_CONTROLCONTROL) { 399 if (client_exitreason != CLIENT_EXIT_NONE) 400 printf("%%exit %s\n", client_exit_message()); 401 else 402 printf("%%exit\n"); 403 printf("\033\\"); 404 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 405 } else if (client_exitreason != CLIENT_EXIT_NONE) 406 fprintf(stderr, "%s\n", client_exit_message()); 407 setblocking(STDIN_FILENO, 1); 408 return (client_exitval); 409 } 410 411 /* Send identify messages to server. */ 412 static void 413 client_send_identify(const char *ttynam, const char *cwd) 414 { 415 const char *s; 416 char **ss; 417 size_t sslen; 418 int fd, flags = client_flags; 419 pid_t pid; 420 421 proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags); 422 423 if ((s = getenv("TERM")) == NULL) 424 s = ""; 425 proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1); 426 427 proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam, 428 strlen(ttynam) + 1); 429 proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1); 430 431 if ((fd = dup(STDIN_FILENO)) == -1) 432 fatal("dup failed"); 433 proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0); 434 435 pid = getpid(); 436 proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid); 437 438 for (ss = environ; *ss != NULL; ss++) { 439 sslen = strlen(*ss) + 1; 440 if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE) 441 continue; 442 proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen); 443 } 444 445 proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0); 446 } 447 448 /* File write error callback. */ 449 static void 450 client_write_error_callback(__unused struct bufferevent *bev, 451 __unused short what, void *arg) 452 { 453 struct client_file *cf = arg; 454 455 log_debug("write error file %d", cf->stream); 456 457 bufferevent_free(cf->event); 458 cf->event = NULL; 459 460 close(cf->fd); 461 cf->fd = -1; 462 463 if (client_exitflag) 464 client_exit(); 465 } 466 467 /* File write callback. */ 468 static void 469 client_write_callback(__unused struct bufferevent *bev, void *arg) 470 { 471 struct client_file *cf = arg; 472 473 if (cf->closed && EVBUFFER_LENGTH(cf->event->output) == 0) { 474 bufferevent_free(cf->event); 475 close(cf->fd); 476 RB_REMOVE(client_files, &client_files, cf); 477 file_free(cf); 478 } 479 480 if (client_exitflag) 481 client_exit(); 482 } 483 484 /* Open write file. */ 485 static void 486 client_write_open(void *data, size_t datalen) 487 { 488 struct msg_write_open *msg = data; 489 const char *path; 490 struct msg_write_ready reply; 491 struct client_file find, *cf; 492 const int flags = O_NONBLOCK|O_WRONLY|O_CREAT; 493 int error = 0; 494 495 if (datalen < sizeof *msg) 496 fatalx("bad MSG_WRITE_OPEN size"); 497 if (datalen == sizeof *msg) 498 path = "-"; 499 else 500 path = (const char *)(msg + 1); 501 log_debug("open write file %d %s", msg->stream, path); 502 503 find.stream = msg->stream; 504 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 505 cf = file_create(NULL, msg->stream, NULL, NULL); 506 RB_INSERT(client_files, &client_files, cf); 507 } else { 508 error = EBADF; 509 goto reply; 510 } 511 if (cf->closed) { 512 error = EBADF; 513 goto reply; 514 } 515 516 cf->fd = -1; 517 if (msg->fd == -1) 518 cf->fd = open(path, msg->flags|flags, 0644); 519 else { 520 if (msg->fd != STDOUT_FILENO && msg->fd != STDERR_FILENO) 521 errno = EBADF; 522 else { 523 cf->fd = dup(msg->fd); 524 if (client_flags & CLIENT_CONTROL) 525 close(msg->fd); /* can only be used once */ 526 } 527 } 528 if (cf->fd == -1) { 529 error = errno; 530 goto reply; 531 } 532 533 cf->event = bufferevent_new(cf->fd, NULL, client_write_callback, 534 client_write_error_callback, cf); 535 bufferevent_enable(cf->event, EV_WRITE); 536 goto reply; 537 538 reply: 539 reply.stream = msg->stream; 540 reply.error = error; 541 proc_send(client_peer, MSG_WRITE_READY, -1, &reply, sizeof reply); 542 } 543 544 /* Write to client file. */ 545 static void 546 client_write_data(void *data, size_t datalen) 547 { 548 struct msg_write_data *msg = data; 549 struct client_file find, *cf; 550 size_t size = datalen - sizeof *msg; 551 552 if (datalen < sizeof *msg) 553 fatalx("bad MSG_WRITE size"); 554 find.stream = msg->stream; 555 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 556 fatalx("unknown stream number"); 557 log_debug("write %zu to file %d", size, cf->stream); 558 559 if (cf->event != NULL) 560 bufferevent_write(cf->event, msg + 1, size); 561 } 562 563 /* Close client file. */ 564 static void 565 client_write_close(void *data, size_t datalen) 566 { 567 struct msg_write_close *msg = data; 568 struct client_file find, *cf; 569 570 if (datalen != sizeof *msg) 571 fatalx("bad MSG_WRITE_CLOSE size"); 572 find.stream = msg->stream; 573 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 574 fatalx("unknown stream number"); 575 log_debug("close file %d", cf->stream); 576 577 if (cf->event == NULL || EVBUFFER_LENGTH(cf->event->output) == 0) { 578 if (cf->event != NULL) 579 bufferevent_free(cf->event); 580 if (cf->fd != -1) 581 close(cf->fd); 582 RB_REMOVE(client_files, &client_files, cf); 583 file_free(cf); 584 } 585 } 586 587 /* File read callback. */ 588 static void 589 client_read_callback(__unused struct bufferevent *bev, void *arg) 590 { 591 struct client_file *cf = arg; 592 void *bdata; 593 size_t bsize; 594 struct msg_read_data *msg; 595 size_t msglen; 596 597 msg = xmalloc(sizeof *msg); 598 for (;;) { 599 bdata = EVBUFFER_DATA(cf->event->input); 600 bsize = EVBUFFER_LENGTH(cf->event->input); 601 602 if (bsize == 0) 603 break; 604 if (bsize > MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg) 605 bsize = MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg; 606 log_debug("read %zu from file %d", bsize, cf->stream); 607 608 msglen = (sizeof *msg) + bsize; 609 msg = xrealloc(msg, msglen); 610 msg->stream = cf->stream; 611 memcpy(msg + 1, bdata, bsize); 612 proc_send(client_peer, MSG_READ, -1, msg, msglen); 613 614 evbuffer_drain(cf->event->input, bsize); 615 } 616 free(msg); 617 } 618 619 /* File read error callback. */ 620 static void 621 client_read_error_callback(__unused struct bufferevent *bev, 622 __unused short what, void *arg) 623 { 624 struct client_file *cf = arg; 625 struct msg_read_done msg; 626 627 log_debug("read error file %d", cf->stream); 628 629 msg.stream = cf->stream; 630 msg.error = 0; 631 proc_send(client_peer, MSG_READ_DONE, -1, &msg, sizeof msg); 632 633 bufferevent_free(cf->event); 634 close(cf->fd); 635 RB_REMOVE(client_files, &client_files, cf); 636 file_free(cf); 637 } 638 639 /* Open read file. */ 640 static void 641 client_read_open(void *data, size_t datalen) 642 { 643 struct msg_read_open *msg = data; 644 const char *path; 645 struct msg_read_done reply; 646 struct client_file find, *cf; 647 const int flags = O_NONBLOCK|O_RDONLY; 648 int error = 0; 649 650 if (datalen < sizeof *msg) 651 fatalx("bad MSG_READ_OPEN size"); 652 if (datalen == sizeof *msg) 653 path = "-"; 654 else 655 path = (const char *)(msg + 1); 656 log_debug("open read file %d %s", msg->stream, path); 657 658 find.stream = msg->stream; 659 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 660 cf = file_create(NULL, msg->stream, NULL, NULL); 661 RB_INSERT(client_files, &client_files, cf); 662 } else { 663 error = EBADF; 664 goto reply; 665 } 666 if (cf->closed) { 667 error = EBADF; 668 goto reply; 669 } 670 671 cf->fd = -1; 672 if (msg->fd == -1) 673 cf->fd = open(path, flags); 674 else { 675 if (msg->fd != STDIN_FILENO) 676 errno = EBADF; 677 else { 678 cf->fd = dup(msg->fd); 679 close(msg->fd); /* can only be used once */ 680 } 681 } 682 if (cf->fd == -1) { 683 error = errno; 684 goto reply; 685 } 686 687 cf->event = bufferevent_new(cf->fd, client_read_callback, NULL, 688 client_read_error_callback, cf); 689 bufferevent_enable(cf->event, EV_READ); 690 return; 691 692 reply: 693 reply.stream = msg->stream; 694 reply.error = error; 695 proc_send(client_peer, MSG_READ_DONE, -1, &reply, sizeof reply); 696 } 697 698 /* Run command in shell; used for -c. */ 699 static __dead void 700 client_exec(const char *shell, const char *shellcmd) 701 { 702 const char *name, *ptr; 703 char *argv0; 704 705 log_debug("shell %s, command %s", shell, shellcmd); 706 707 ptr = strrchr(shell, '/'); 708 if (ptr != NULL && *(ptr + 1) != '\0') 709 name = ptr + 1; 710 else 711 name = shell; 712 if (client_flags & CLIENT_LOGIN) 713 xasprintf(&argv0, "-%s", name); 714 else 715 xasprintf(&argv0, "%s", name); 716 setenv("SHELL", shell, 1); 717 718 proc_clear_signals(client_proc, 1); 719 720 setblocking(STDIN_FILENO, 1); 721 setblocking(STDOUT_FILENO, 1); 722 setblocking(STDERR_FILENO, 1); 723 closefrom(STDERR_FILENO + 1); 724 725 execl(shell, argv0, "-c", shellcmd, (char *) NULL); 726 fatal("execl failed"); 727 } 728 729 /* Callback to handle signals in the client. */ 730 static void 731 client_signal(int sig) 732 { 733 struct sigaction sigact; 734 int status; 735 736 if (sig == SIGCHLD) 737 waitpid(WAIT_ANY, &status, WNOHANG); 738 else if (!client_attached) { 739 if (sig == SIGTERM) 740 proc_exit(client_proc); 741 } else { 742 switch (sig) { 743 case SIGHUP: 744 client_exitreason = CLIENT_EXIT_LOST_TTY; 745 client_exitval = 1; 746 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 747 break; 748 case SIGTERM: 749 client_exitreason = CLIENT_EXIT_TERMINATED; 750 client_exitval = 1; 751 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 752 break; 753 case SIGWINCH: 754 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 755 break; 756 case SIGCONT: 757 memset(&sigact, 0, sizeof sigact); 758 sigemptyset(&sigact.sa_mask); 759 sigact.sa_flags = SA_RESTART; 760 sigact.sa_handler = SIG_IGN; 761 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 762 fatal("sigaction failed"); 763 proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0); 764 break; 765 } 766 } 767 } 768 769 /* Callback for client read events. */ 770 static void 771 client_dispatch(struct imsg *imsg, __unused void *arg) 772 { 773 if (imsg == NULL) { 774 client_exitreason = CLIENT_EXIT_LOST_SERVER; 775 client_exitval = 1; 776 proc_exit(client_proc); 777 return; 778 } 779 780 if (client_attached) 781 client_dispatch_attached(imsg); 782 else 783 client_dispatch_wait(imsg); 784 } 785 786 /* Dispatch imsgs when in wait state (before MSG_READY). */ 787 static void 788 client_dispatch_wait(struct imsg *imsg) 789 { 790 char *data; 791 ssize_t datalen; 792 int retval; 793 static int pledge_applied; 794 795 /* 796 * "sendfd" is no longer required once all of the identify messages 797 * have been sent. We know the server won't send us anything until that 798 * point (because we don't ask it to), so we can drop "sendfd" once we 799 * get the first message from the server. 800 */ 801 if (!pledge_applied) { 802 if (pledge( 803 "stdio rpath wpath cpath unix proc exec tty", 804 NULL) != 0) 805 fatal("pledge failed"); 806 pledge_applied = 1; 807 } 808 809 data = imsg->data; 810 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 811 812 switch (imsg->hdr.type) { 813 case MSG_EXIT: 814 case MSG_SHUTDOWN: 815 if (datalen != sizeof retval && datalen != 0) 816 fatalx("bad MSG_EXIT size"); 817 if (datalen == sizeof retval) { 818 memcpy(&retval, data, sizeof retval); 819 client_exitval = retval; 820 } 821 client_exitflag = 1; 822 client_exit(); 823 break; 824 case MSG_READY: 825 if (datalen != 0) 826 fatalx("bad MSG_READY size"); 827 828 client_attached = 1; 829 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 830 break; 831 case MSG_VERSION: 832 if (datalen != 0) 833 fatalx("bad MSG_VERSION size"); 834 835 fprintf(stderr, "protocol version mismatch " 836 "(client %d, server %u)\n", PROTOCOL_VERSION, 837 imsg->hdr.peerid & 0xff); 838 client_exitval = 1; 839 proc_exit(client_proc); 840 break; 841 case MSG_SHELL: 842 if (datalen == 0 || data[datalen - 1] != '\0') 843 fatalx("bad MSG_SHELL string"); 844 845 client_exec(data, shell_command); 846 /* NOTREACHED */ 847 case MSG_DETACH: 848 case MSG_DETACHKILL: 849 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 850 break; 851 case MSG_EXITED: 852 proc_exit(client_proc); 853 break; 854 case MSG_READ_OPEN: 855 client_read_open(data, datalen); 856 break; 857 case MSG_WRITE_OPEN: 858 client_write_open(data, datalen); 859 break; 860 case MSG_WRITE: 861 client_write_data(data, datalen); 862 break; 863 case MSG_WRITE_CLOSE: 864 client_write_close(data, datalen); 865 break; 866 case MSG_OLDSTDERR: 867 case MSG_OLDSTDIN: 868 case MSG_OLDSTDOUT: 869 fprintf(stderr, "server version is too old for client\n"); 870 proc_exit(client_proc); 871 break; 872 } 873 } 874 875 /* Dispatch imsgs in attached state (after MSG_READY). */ 876 static void 877 client_dispatch_attached(struct imsg *imsg) 878 { 879 struct sigaction sigact; 880 char *data; 881 ssize_t datalen; 882 883 data = imsg->data; 884 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 885 886 switch (imsg->hdr.type) { 887 case MSG_DETACH: 888 case MSG_DETACHKILL: 889 if (datalen == 0 || data[datalen - 1] != '\0') 890 fatalx("bad MSG_DETACH string"); 891 892 client_exitsession = xstrdup(data); 893 client_exittype = imsg->hdr.type; 894 if (imsg->hdr.type == MSG_DETACHKILL) 895 client_exitreason = CLIENT_EXIT_DETACHED_HUP; 896 else 897 client_exitreason = CLIENT_EXIT_DETACHED; 898 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 899 break; 900 case MSG_EXEC: 901 if (datalen == 0 || data[datalen - 1] != '\0' || 902 strlen(data) + 1 == (size_t)datalen) 903 fatalx("bad MSG_EXEC string"); 904 client_execcmd = xstrdup(data); 905 client_execshell = xstrdup(data + strlen(data) + 1); 906 907 client_exittype = imsg->hdr.type; 908 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 909 break; 910 case MSG_EXIT: 911 if (datalen != 0 && datalen != sizeof (int)) 912 fatalx("bad MSG_EXIT size"); 913 914 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 915 client_exitreason = CLIENT_EXIT_EXITED; 916 break; 917 case MSG_EXITED: 918 if (datalen != 0) 919 fatalx("bad MSG_EXITED size"); 920 921 proc_exit(client_proc); 922 break; 923 case MSG_SHUTDOWN: 924 if (datalen != 0) 925 fatalx("bad MSG_SHUTDOWN size"); 926 927 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 928 client_exitreason = CLIENT_EXIT_SERVER_EXITED; 929 client_exitval = 1; 930 break; 931 case MSG_SUSPEND: 932 if (datalen != 0) 933 fatalx("bad MSG_SUSPEND size"); 934 935 memset(&sigact, 0, sizeof sigact); 936 sigemptyset(&sigact.sa_mask); 937 sigact.sa_flags = SA_RESTART; 938 sigact.sa_handler = SIG_DFL; 939 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 940 fatal("sigaction failed"); 941 kill(getpid(), SIGTSTP); 942 break; 943 case MSG_LOCK: 944 if (datalen == 0 || data[datalen - 1] != '\0') 945 fatalx("bad MSG_LOCK string"); 946 947 system(data); 948 proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0); 949 break; 950 } 951 } 952