1 /* $OpenBSD$ */ 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 #include <sys/file.h> 24 25 #include <errno.h> 26 #include <event.h> 27 #include <fcntl.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 #ifdef NOKERNINFO 338 tio.c_lflag = NOKERNINFO; 339 #endif 340 tio.c_cflag = CREAD|CS8|HUPCL; 341 tio.c_cc[VMIN] = 1; 342 tio.c_cc[VTIME] = 0; 343 cfsetispeed(&tio, cfgetispeed(&saved_tio)); 344 cfsetospeed(&tio, cfgetospeed(&saved_tio)); 345 tcsetattr(STDIN_FILENO, TCSANOW, &tio); 346 } 347 348 /* Send identify messages. */ 349 client_send_identify(ttynam, cwd); 350 351 /* Send first command. */ 352 if (msg == MSG_COMMAND) { 353 /* How big is the command? */ 354 size = 0; 355 for (i = 0; i < argc; i++) 356 size += strlen(argv[i]) + 1; 357 if (size > MAX_IMSGSIZE - (sizeof *data)) { 358 fprintf(stderr, "command too long\n"); 359 return (1); 360 } 361 data = xmalloc((sizeof *data) + size); 362 363 /* Prepare command for server. */ 364 data->argc = argc; 365 if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) { 366 fprintf(stderr, "command too long\n"); 367 free(data); 368 return (1); 369 } 370 size += sizeof *data; 371 372 /* Send the command. */ 373 if (proc_send(client_peer, msg, -1, data, size) != 0) { 374 fprintf(stderr, "failed to send command\n"); 375 free(data); 376 return (1); 377 } 378 free(data); 379 } else if (msg == MSG_SHELL) 380 proc_send(client_peer, msg, -1, NULL, 0); 381 382 /* Start main loop. */ 383 proc_loop(client_proc, NULL); 384 385 /* Run command if user requested exec, instead of exiting. */ 386 if (client_exittype == MSG_EXEC) { 387 if (client_flags & CLIENT_CONTROLCONTROL) 388 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 389 client_exec(client_execshell, client_execcmd); 390 } 391 392 /* Print the exit message, if any, and exit. */ 393 if (client_attached) { 394 if (client_exitreason != CLIENT_EXIT_NONE) 395 printf("[%s]\n", client_exit_message()); 396 397 ppid = getppid(); 398 if (client_exittype == MSG_DETACHKILL && ppid > 1) 399 kill(ppid, SIGHUP); 400 } else if (client_flags & CLIENT_CONTROLCONTROL) { 401 if (client_exitreason != CLIENT_EXIT_NONE) 402 printf("%%exit %s\n", client_exit_message()); 403 else 404 printf("%%exit\n"); 405 printf("\033\\"); 406 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 407 } else if (client_exitreason != CLIENT_EXIT_NONE) 408 fprintf(stderr, "%s\n", client_exit_message()); 409 setblocking(STDIN_FILENO, 1); 410 return (client_exitval); 411 } 412 413 /* Send identify messages to server. */ 414 static void 415 client_send_identify(const char *ttynam, const char *cwd) 416 { 417 const char *s; 418 char **ss; 419 size_t sslen; 420 int fd, flags = client_flags; 421 pid_t pid; 422 423 proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags); 424 425 if ((s = getenv("TERM")) == NULL) 426 s = ""; 427 proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1); 428 429 proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam, 430 strlen(ttynam) + 1); 431 proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1); 432 433 if ((fd = dup(STDIN_FILENO)) == -1) 434 fatal("dup failed"); 435 proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0); 436 437 pid = getpid(); 438 proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid); 439 440 for (ss = environ; *ss != NULL; ss++) { 441 sslen = strlen(*ss) + 1; 442 if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE) 443 continue; 444 proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen); 445 } 446 447 proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0); 448 } 449 450 /* File write error callback. */ 451 static void 452 client_write_error_callback(__unused struct bufferevent *bev, 453 __unused short what, void *arg) 454 { 455 struct client_file *cf = arg; 456 457 log_debug("write error file %d", cf->stream); 458 459 bufferevent_free(cf->event); 460 cf->event = NULL; 461 462 close(cf->fd); 463 cf->fd = -1; 464 465 if (client_exitflag) 466 client_exit(); 467 } 468 469 /* File write callback. */ 470 static void 471 client_write_callback(__unused struct bufferevent *bev, void *arg) 472 { 473 struct client_file *cf = arg; 474 475 if (cf->closed && EVBUFFER_LENGTH(cf->event->output) == 0) { 476 bufferevent_free(cf->event); 477 close(cf->fd); 478 RB_REMOVE(client_files, &client_files, cf); 479 file_free(cf); 480 } 481 482 if (client_exitflag) 483 client_exit(); 484 } 485 486 /* Open write file. */ 487 static void 488 client_write_open(void *data, size_t datalen) 489 { 490 struct msg_write_open *msg = data; 491 const char *path; 492 struct msg_write_ready reply; 493 struct client_file find, *cf; 494 const int flags = O_NONBLOCK|O_WRONLY|O_CREAT; 495 int error = 0; 496 497 if (datalen < sizeof *msg) 498 fatalx("bad MSG_WRITE_OPEN size"); 499 if (datalen == sizeof *msg) 500 path = "-"; 501 else 502 path = (const char *)(msg + 1); 503 log_debug("open write file %d %s", msg->stream, path); 504 505 find.stream = msg->stream; 506 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 507 cf = file_create(NULL, msg->stream, NULL, NULL); 508 RB_INSERT(client_files, &client_files, cf); 509 } else { 510 error = EBADF; 511 goto reply; 512 } 513 if (cf->closed) { 514 error = EBADF; 515 goto reply; 516 } 517 518 cf->fd = -1; 519 if (msg->fd == -1) 520 cf->fd = open(path, msg->flags|flags, 0644); 521 else { 522 if (msg->fd != STDOUT_FILENO && msg->fd != STDERR_FILENO) 523 errno = EBADF; 524 else { 525 cf->fd = dup(msg->fd); 526 if (~client_flags & CLIENT_CONTROL) 527 close(msg->fd); /* can only be used once */ 528 } 529 } 530 if (cf->fd == -1) { 531 error = errno; 532 goto reply; 533 } 534 535 cf->event = bufferevent_new(cf->fd, NULL, client_write_callback, 536 client_write_error_callback, cf); 537 bufferevent_enable(cf->event, EV_WRITE); 538 goto reply; 539 540 reply: 541 reply.stream = msg->stream; 542 reply.error = error; 543 proc_send(client_peer, MSG_WRITE_READY, -1, &reply, sizeof reply); 544 } 545 546 /* Write to client file. */ 547 static void 548 client_write_data(void *data, size_t datalen) 549 { 550 struct msg_write_data *msg = data; 551 struct client_file find, *cf; 552 size_t size = datalen - sizeof *msg; 553 554 if (datalen < sizeof *msg) 555 fatalx("bad MSG_WRITE size"); 556 find.stream = msg->stream; 557 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 558 fatalx("unknown stream number"); 559 log_debug("write %zu to file %d", size, cf->stream); 560 561 if (cf->event != NULL) 562 bufferevent_write(cf->event, msg + 1, size); 563 } 564 565 /* Close client file. */ 566 static void 567 client_write_close(void *data, size_t datalen) 568 { 569 struct msg_write_close *msg = data; 570 struct client_file find, *cf; 571 572 if (datalen != sizeof *msg) 573 fatalx("bad MSG_WRITE_CLOSE size"); 574 find.stream = msg->stream; 575 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 576 fatalx("unknown stream number"); 577 log_debug("close file %d", cf->stream); 578 579 if (cf->event == NULL || EVBUFFER_LENGTH(cf->event->output) == 0) { 580 if (cf->event != NULL) 581 bufferevent_free(cf->event); 582 if (cf->fd != -1) 583 close(cf->fd); 584 RB_REMOVE(client_files, &client_files, cf); 585 file_free(cf); 586 } 587 } 588 589 /* File read callback. */ 590 static void 591 client_read_callback(__unused struct bufferevent *bev, void *arg) 592 { 593 struct client_file *cf = arg; 594 void *bdata; 595 size_t bsize; 596 struct msg_read_data *msg; 597 size_t msglen; 598 599 msg = xmalloc(sizeof *msg); 600 for (;;) { 601 bdata = EVBUFFER_DATA(cf->event->input); 602 bsize = EVBUFFER_LENGTH(cf->event->input); 603 604 if (bsize == 0) 605 break; 606 if (bsize > MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg) 607 bsize = MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg; 608 log_debug("read %zu from file %d", bsize, cf->stream); 609 610 msglen = (sizeof *msg) + bsize; 611 msg = xrealloc(msg, msglen); 612 msg->stream = cf->stream; 613 memcpy(msg + 1, bdata, bsize); 614 proc_send(client_peer, MSG_READ, -1, msg, msglen); 615 616 evbuffer_drain(cf->event->input, bsize); 617 } 618 free(msg); 619 } 620 621 /* File read error callback. */ 622 static void 623 client_read_error_callback(__unused struct bufferevent *bev, 624 __unused short what, void *arg) 625 { 626 struct client_file *cf = arg; 627 struct msg_read_done msg; 628 629 log_debug("read error file %d", cf->stream); 630 631 msg.stream = cf->stream; 632 msg.error = 0; 633 proc_send(client_peer, MSG_READ_DONE, -1, &msg, sizeof msg); 634 635 bufferevent_free(cf->event); 636 close(cf->fd); 637 RB_REMOVE(client_files, &client_files, cf); 638 file_free(cf); 639 } 640 641 /* Open read file. */ 642 static void 643 client_read_open(void *data, size_t datalen) 644 { 645 struct msg_read_open *msg = data; 646 const char *path; 647 struct msg_read_done reply; 648 struct client_file find, *cf; 649 const int flags = O_NONBLOCK|O_RDONLY; 650 int error = 0; 651 652 if (datalen < sizeof *msg) 653 fatalx("bad MSG_READ_OPEN size"); 654 if (datalen == sizeof *msg) 655 path = "-"; 656 else 657 path = (const char *)(msg + 1); 658 log_debug("open read file %d %s", msg->stream, path); 659 660 find.stream = msg->stream; 661 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 662 cf = file_create(NULL, msg->stream, NULL, NULL); 663 RB_INSERT(client_files, &client_files, cf); 664 } else { 665 error = EBADF; 666 goto reply; 667 } 668 if (cf->closed) { 669 error = EBADF; 670 goto reply; 671 } 672 673 cf->fd = -1; 674 if (msg->fd == -1) 675 cf->fd = open(path, flags); 676 else { 677 if (msg->fd != STDIN_FILENO) 678 errno = EBADF; 679 else { 680 cf->fd = dup(msg->fd); 681 if (~client_flags & CLIENT_CONTROL) 682 close(msg->fd); /* can only be used once */ 683 } 684 } 685 if (cf->fd == -1) { 686 error = errno; 687 goto reply; 688 } 689 690 cf->event = bufferevent_new(cf->fd, client_read_callback, NULL, 691 client_read_error_callback, cf); 692 bufferevent_enable(cf->event, EV_READ); 693 return; 694 695 reply: 696 reply.stream = msg->stream; 697 reply.error = error; 698 proc_send(client_peer, MSG_READ_DONE, -1, &reply, sizeof reply); 699 } 700 701 /* Run command in shell; used for -c. */ 702 static __dead void 703 client_exec(const char *shell, const char *shellcmd) 704 { 705 const char *name, *ptr; 706 char *argv0; 707 708 log_debug("shell %s, command %s", shell, shellcmd); 709 710 ptr = strrchr(shell, '/'); 711 if (ptr != NULL && *(ptr + 1) != '\0') 712 name = ptr + 1; 713 else 714 name = shell; 715 if (client_flags & CLIENT_LOGIN) 716 xasprintf(&argv0, "-%s", name); 717 else 718 xasprintf(&argv0, "%s", name); 719 setenv("SHELL", shell, 1); 720 721 proc_clear_signals(client_proc, 1); 722 723 setblocking(STDIN_FILENO, 1); 724 setblocking(STDOUT_FILENO, 1); 725 setblocking(STDERR_FILENO, 1); 726 closefrom(STDERR_FILENO + 1); 727 728 execl(shell, argv0, "-c", shellcmd, (char *) NULL); 729 fatal("execl failed"); 730 } 731 732 /* Callback to handle signals in the client. */ 733 static void 734 client_signal(int sig) 735 { 736 struct sigaction sigact; 737 int status; 738 739 if (sig == SIGCHLD) 740 waitpid(WAIT_ANY, &status, WNOHANG); 741 else if (!client_attached) { 742 if (sig == SIGTERM) 743 proc_exit(client_proc); 744 } else { 745 switch (sig) { 746 case SIGHUP: 747 client_exitreason = CLIENT_EXIT_LOST_TTY; 748 client_exitval = 1; 749 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 750 break; 751 case SIGTERM: 752 client_exitreason = CLIENT_EXIT_TERMINATED; 753 client_exitval = 1; 754 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 755 break; 756 case SIGWINCH: 757 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 758 break; 759 case SIGCONT: 760 memset(&sigact, 0, sizeof sigact); 761 sigemptyset(&sigact.sa_mask); 762 sigact.sa_flags = SA_RESTART; 763 sigact.sa_handler = SIG_IGN; 764 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 765 fatal("sigaction failed"); 766 proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0); 767 break; 768 } 769 } 770 } 771 772 /* Callback for client read events. */ 773 static void 774 client_dispatch(struct imsg *imsg, __unused void *arg) 775 { 776 if (imsg == NULL) { 777 client_exitreason = CLIENT_EXIT_LOST_SERVER; 778 client_exitval = 1; 779 proc_exit(client_proc); 780 return; 781 } 782 783 if (client_attached) 784 client_dispatch_attached(imsg); 785 else 786 client_dispatch_wait(imsg); 787 } 788 789 /* Dispatch imsgs when in wait state (before MSG_READY). */ 790 static void 791 client_dispatch_wait(struct imsg *imsg) 792 { 793 char *data; 794 ssize_t datalen; 795 int retval; 796 static int pledge_applied; 797 798 /* 799 * "sendfd" is no longer required once all of the identify messages 800 * have been sent. We know the server won't send us anything until that 801 * point (because we don't ask it to), so we can drop "sendfd" once we 802 * get the first message from the server. 803 */ 804 if (!pledge_applied) { 805 if (pledge( 806 "stdio rpath wpath cpath unix proc exec tty", 807 NULL) != 0) 808 fatal("pledge failed"); 809 pledge_applied = 1; 810 } 811 812 data = imsg->data; 813 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 814 815 switch (imsg->hdr.type) { 816 case MSG_EXIT: 817 case MSG_SHUTDOWN: 818 if (datalen != sizeof retval && datalen != 0) 819 fatalx("bad MSG_EXIT size"); 820 if (datalen == sizeof retval) { 821 memcpy(&retval, data, sizeof retval); 822 client_exitval = retval; 823 } 824 client_exitflag = 1; 825 client_exit(); 826 break; 827 case MSG_READY: 828 if (datalen != 0) 829 fatalx("bad MSG_READY size"); 830 831 client_attached = 1; 832 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 833 break; 834 case MSG_VERSION: 835 if (datalen != 0) 836 fatalx("bad MSG_VERSION size"); 837 838 fprintf(stderr, "protocol version mismatch " 839 "(client %d, server %u)\n", PROTOCOL_VERSION, 840 imsg->hdr.peerid & 0xff); 841 client_exitval = 1; 842 proc_exit(client_proc); 843 break; 844 case MSG_SHELL: 845 if (datalen == 0 || data[datalen - 1] != '\0') 846 fatalx("bad MSG_SHELL string"); 847 848 client_exec(data, shell_command); 849 /* NOTREACHED */ 850 case MSG_DETACH: 851 case MSG_DETACHKILL: 852 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 853 break; 854 case MSG_EXITED: 855 proc_exit(client_proc); 856 break; 857 case MSG_READ_OPEN: 858 client_read_open(data, datalen); 859 break; 860 case MSG_WRITE_OPEN: 861 client_write_open(data, datalen); 862 break; 863 case MSG_WRITE: 864 client_write_data(data, datalen); 865 break; 866 case MSG_WRITE_CLOSE: 867 client_write_close(data, datalen); 868 break; 869 case MSG_OLDSTDERR: 870 case MSG_OLDSTDIN: 871 case MSG_OLDSTDOUT: 872 fprintf(stderr, "server version is too old for client\n"); 873 proc_exit(client_proc); 874 break; 875 } 876 } 877 878 /* Dispatch imsgs in attached state (after MSG_READY). */ 879 static void 880 client_dispatch_attached(struct imsg *imsg) 881 { 882 struct sigaction sigact; 883 char *data; 884 ssize_t datalen; 885 886 data = imsg->data; 887 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 888 889 switch (imsg->hdr.type) { 890 case MSG_DETACH: 891 case MSG_DETACHKILL: 892 if (datalen == 0 || data[datalen - 1] != '\0') 893 fatalx("bad MSG_DETACH string"); 894 895 client_exitsession = xstrdup(data); 896 client_exittype = imsg->hdr.type; 897 if (imsg->hdr.type == MSG_DETACHKILL) 898 client_exitreason = CLIENT_EXIT_DETACHED_HUP; 899 else 900 client_exitreason = CLIENT_EXIT_DETACHED; 901 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 902 break; 903 case MSG_EXEC: 904 if (datalen == 0 || data[datalen - 1] != '\0' || 905 strlen(data) + 1 == (size_t)datalen) 906 fatalx("bad MSG_EXEC string"); 907 client_execcmd = xstrdup(data); 908 client_execshell = xstrdup(data + strlen(data) + 1); 909 910 client_exittype = imsg->hdr.type; 911 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 912 break; 913 case MSG_EXIT: 914 if (datalen != 0 && datalen != sizeof (int)) 915 fatalx("bad MSG_EXIT size"); 916 917 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 918 client_exitreason = CLIENT_EXIT_EXITED; 919 break; 920 case MSG_EXITED: 921 if (datalen != 0) 922 fatalx("bad MSG_EXITED size"); 923 924 proc_exit(client_proc); 925 break; 926 case MSG_SHUTDOWN: 927 if (datalen != 0) 928 fatalx("bad MSG_SHUTDOWN size"); 929 930 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 931 client_exitreason = CLIENT_EXIT_SERVER_EXITED; 932 client_exitval = 1; 933 break; 934 case MSG_SUSPEND: 935 if (datalen != 0) 936 fatalx("bad MSG_SUSPEND size"); 937 938 memset(&sigact, 0, sizeof sigact); 939 sigemptyset(&sigact.sa_mask); 940 sigact.sa_flags = SA_RESTART; 941 sigact.sa_handler = SIG_DFL; 942 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 943 fatal("sigaction failed"); 944 kill(getpid(), SIGTSTP); 945 break; 946 case MSG_LOCK: 947 if (datalen == 0 || data[datalen - 1] != '\0') 948 fatalx("bad MSG_LOCK string"); 949 950 system(data); 951 proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0); 952 break; 953 } 954 } 955