1 /* $OpenBSD: client.c,v 1.148 2020/06/18 08:34:22 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 enum { 40 CLIENT_EXIT_NONE, 41 CLIENT_EXIT_DETACHED, 42 CLIENT_EXIT_DETACHED_HUP, 43 CLIENT_EXIT_LOST_TTY, 44 CLIENT_EXIT_TERMINATED, 45 CLIENT_EXIT_LOST_SERVER, 46 CLIENT_EXIT_EXITED, 47 CLIENT_EXIT_SERVER_EXITED, 48 CLIENT_EXIT_MESSAGE_PROVIDED 49 } client_exitreason = CLIENT_EXIT_NONE; 50 static int client_exitflag; 51 static int client_exitval; 52 static enum msgtype client_exittype; 53 static const char *client_exitsession; 54 static char *client_exitmessage; 55 static const char *client_execshell; 56 static const char *client_execcmd; 57 static int client_attached; 58 static struct client_files client_files = RB_INITIALIZER(&client_files); 59 60 static __dead void client_exec(const char *,const char *); 61 static int client_get_lock(char *); 62 static int client_connect(struct event_base *, const char *, int); 63 static void client_send_identify(const char *, const char *, int); 64 static void client_signal(int); 65 static void client_dispatch(struct imsg *, void *); 66 static void client_dispatch_attached(struct imsg *); 67 static void client_dispatch_wait(struct imsg *); 68 static const char *client_exit_message(void); 69 70 /* 71 * Get server create lock. If already held then server start is happening in 72 * another client, so block until the lock is released and return -2 to 73 * retry. Return -1 on failure to continue and start the server anyway. 74 */ 75 static int 76 client_get_lock(char *lockfile) 77 { 78 int lockfd; 79 80 log_debug("lock file is %s", lockfile); 81 82 if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1) { 83 log_debug("open failed: %s", strerror(errno)); 84 return (-1); 85 } 86 87 if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) { 88 log_debug("flock failed: %s", strerror(errno)); 89 if (errno != EAGAIN) 90 return (lockfd); 91 while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR) 92 /* nothing */; 93 close(lockfd); 94 return (-2); 95 } 96 log_debug("flock succeeded"); 97 98 return (lockfd); 99 } 100 101 /* Connect client to server. */ 102 static int 103 client_connect(struct event_base *base, const char *path, int flags) 104 { 105 struct sockaddr_un sa; 106 size_t size; 107 int fd, lockfd = -1, locked = 0; 108 char *lockfile = NULL; 109 110 memset(&sa, 0, sizeof sa); 111 sa.sun_family = AF_UNIX; 112 size = strlcpy(sa.sun_path, path, sizeof sa.sun_path); 113 if (size >= sizeof sa.sun_path) { 114 errno = ENAMETOOLONG; 115 return (-1); 116 } 117 log_debug("socket is %s", path); 118 119 retry: 120 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 121 return (-1); 122 123 log_debug("trying connect"); 124 if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 125 log_debug("connect failed: %s", strerror(errno)); 126 if (errno != ECONNREFUSED && errno != ENOENT) 127 goto failed; 128 if (~flags & CLIENT_STARTSERVER) 129 goto failed; 130 close(fd); 131 132 if (!locked) { 133 xasprintf(&lockfile, "%s.lock", path); 134 if ((lockfd = client_get_lock(lockfile)) < 0) { 135 log_debug("didn't get lock (%d)", lockfd); 136 137 free(lockfile); 138 lockfile = NULL; 139 140 if (lockfd == -2) 141 goto retry; 142 } 143 log_debug("got lock (%d)", lockfd); 144 145 /* 146 * Always retry at least once, even if we got the lock, 147 * because another client could have taken the lock, 148 * started the server and released the lock between our 149 * connect() and flock(). 150 */ 151 locked = 1; 152 goto retry; 153 } 154 155 if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) { 156 free(lockfile); 157 close(lockfd); 158 return (-1); 159 } 160 fd = server_start(client_proc, flags, base, lockfd, lockfile); 161 } 162 163 if (locked && lockfd >= 0) { 164 free(lockfile); 165 close(lockfd); 166 } 167 setblocking(fd, 0); 168 return (fd); 169 170 failed: 171 if (locked) { 172 free(lockfile); 173 close(lockfd); 174 } 175 close(fd); 176 return (-1); 177 } 178 179 /* Get exit string from reason number. */ 180 const char * 181 client_exit_message(void) 182 { 183 static char msg[256]; 184 185 switch (client_exitreason) { 186 case CLIENT_EXIT_NONE: 187 break; 188 case CLIENT_EXIT_DETACHED: 189 if (client_exitsession != NULL) { 190 xsnprintf(msg, sizeof msg, "detached " 191 "(from session %s)", client_exitsession); 192 return (msg); 193 } 194 return ("detached"); 195 case CLIENT_EXIT_DETACHED_HUP: 196 if (client_exitsession != NULL) { 197 xsnprintf(msg, sizeof msg, "detached and SIGHUP " 198 "(from session %s)", client_exitsession); 199 return (msg); 200 } 201 return ("detached and SIGHUP"); 202 case CLIENT_EXIT_LOST_TTY: 203 return ("lost tty"); 204 case CLIENT_EXIT_TERMINATED: 205 return ("terminated"); 206 case CLIENT_EXIT_LOST_SERVER: 207 return ("server exited unexpectedly"); 208 case CLIENT_EXIT_EXITED: 209 return ("exited"); 210 case CLIENT_EXIT_SERVER_EXITED: 211 return ("server exited"); 212 case CLIENT_EXIT_MESSAGE_PROVIDED: 213 return (client_exitmessage); 214 } 215 return ("unknown reason"); 216 } 217 218 /* Exit if all streams flushed. */ 219 static void 220 client_exit(void) 221 { 222 struct client_file *cf; 223 size_t left; 224 int waiting = 0; 225 226 RB_FOREACH (cf, client_files, &client_files) { 227 if (cf->event == NULL) 228 continue; 229 left = EVBUFFER_LENGTH(cf->event->output); 230 if (left != 0) { 231 waiting++; 232 log_debug("file %u %zu bytes left", cf->stream, left); 233 } 234 } 235 if (waiting == 0) 236 proc_exit(client_proc); 237 } 238 239 /* Client main loop. */ 240 int 241 client_main(struct event_base *base, int argc, char **argv, int flags, int feat) 242 { 243 struct cmd_parse_result *pr; 244 struct msg_command *data; 245 int fd, i; 246 const char *ttynam, *cwd; 247 pid_t ppid; 248 enum msgtype msg; 249 struct termios tio, saved_tio; 250 size_t size, linesize = 0; 251 ssize_t linelen; 252 char *line = NULL; 253 254 /* Ignore SIGCHLD now or daemon() in the server will leave a zombie. */ 255 signal(SIGCHLD, SIG_IGN); 256 257 /* Set up the initial command. */ 258 if (shell_command != NULL) { 259 msg = MSG_SHELL; 260 flags |= CLIENT_STARTSERVER; 261 } else if (argc == 0) { 262 msg = MSG_COMMAND; 263 flags |= CLIENT_STARTSERVER; 264 } else { 265 msg = MSG_COMMAND; 266 267 /* 268 * It sucks parsing the command string twice (in client and 269 * later in server) but it is necessary to get the start server 270 * flag. 271 */ 272 pr = cmd_parse_from_arguments(argc, argv, NULL); 273 if (pr->status == CMD_PARSE_SUCCESS) { 274 if (cmd_list_any_have(pr->cmdlist, CMD_STARTSERVER)) 275 flags |= CLIENT_STARTSERVER; 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 /* Save the flags. */ 286 client_flags = flags; 287 log_debug("flags are %#llx", client_flags); 288 289 /* Initialize the client socket and start the server. */ 290 fd = client_connect(base, socket_path, client_flags); 291 if (fd == -1) { 292 if (errno == ECONNREFUSED) { 293 fprintf(stderr, "no server running on %s\n", 294 socket_path); 295 } else { 296 fprintf(stderr, "error connecting to %s (%s)\n", 297 socket_path, strerror(errno)); 298 } 299 return (1); 300 } 301 client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL); 302 303 /* Save these before pledge(). */ 304 if ((cwd = find_cwd()) == NULL && (cwd = find_home()) == NULL) 305 cwd = "/"; 306 if ((ttynam = ttyname(STDIN_FILENO)) == NULL) 307 ttynam = ""; 308 309 /* 310 * Drop privileges for client. "proc exec" is needed for -c and for 311 * locking (which uses system(3)). 312 * 313 * "tty" is needed to restore termios(4) and also for some reason -CC 314 * does not work properly without it (input is not recognised). 315 * 316 * "sendfd" is dropped later in client_dispatch_wait(). 317 */ 318 if (pledge( 319 "stdio rpath wpath cpath unix sendfd proc exec tty", 320 NULL) != 0) 321 fatal("pledge failed"); 322 323 /* Free stuff that is not used in the client. */ 324 if (ptm_fd != -1) 325 close(ptm_fd); 326 options_free(global_options); 327 options_free(global_s_options); 328 options_free(global_w_options); 329 environ_free(global_environ); 330 331 /* Set up control mode. */ 332 if (client_flags & CLIENT_CONTROLCONTROL) { 333 if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) { 334 fprintf(stderr, "tcgetattr failed: %s\n", 335 strerror(errno)); 336 return (1); 337 } 338 cfmakeraw(&tio); 339 tio.c_iflag = ICRNL|IXANY; 340 tio.c_oflag = OPOST|ONLCR; 341 tio.c_lflag = NOKERNINFO; 342 tio.c_cflag = CREAD|CS8|HUPCL; 343 tio.c_cc[VMIN] = 1; 344 tio.c_cc[VTIME] = 0; 345 cfsetispeed(&tio, cfgetispeed(&saved_tio)); 346 cfsetospeed(&tio, cfgetospeed(&saved_tio)); 347 tcsetattr(STDIN_FILENO, TCSANOW, &tio); 348 } 349 350 /* Send identify messages. */ 351 client_send_identify(ttynam, cwd, feat); 352 353 /* Send first command. */ 354 if (msg == MSG_COMMAND) { 355 /* How big is the command? */ 356 size = 0; 357 for (i = 0; i < argc; i++) 358 size += strlen(argv[i]) + 1; 359 if (size > MAX_IMSGSIZE - (sizeof *data)) { 360 fprintf(stderr, "command too long\n"); 361 return (1); 362 } 363 data = xmalloc((sizeof *data) + size); 364 365 /* Prepare command for server. */ 366 data->argc = argc; 367 if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) { 368 fprintf(stderr, "command too long\n"); 369 free(data); 370 return (1); 371 } 372 size += sizeof *data; 373 374 /* Send the command. */ 375 if (proc_send(client_peer, msg, -1, data, size) != 0) { 376 fprintf(stderr, "failed to send command\n"); 377 free(data); 378 return (1); 379 } 380 free(data); 381 } else if (msg == MSG_SHELL) 382 proc_send(client_peer, msg, -1, NULL, 0); 383 384 /* Start main loop. */ 385 proc_loop(client_proc, NULL); 386 387 /* Run command if user requested exec, instead of exiting. */ 388 if (client_exittype == MSG_EXEC) { 389 if (client_flags & CLIENT_CONTROLCONTROL) 390 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 391 client_exec(client_execshell, client_execcmd); 392 } 393 394 /* Restore streams to blocking. */ 395 setblocking(STDIN_FILENO, 1); 396 setblocking(STDOUT_FILENO, 1); 397 setblocking(STDERR_FILENO, 1); 398 399 /* Print the exit message, if any, and exit. */ 400 if (client_attached) { 401 if (client_exitreason != CLIENT_EXIT_NONE) 402 printf("[%s]\n", client_exit_message()); 403 404 ppid = getppid(); 405 if (client_exittype == MSG_DETACHKILL && ppid > 1) 406 kill(ppid, SIGHUP); 407 } else if (client_flags & CLIENT_CONTROL) { 408 if (client_exitreason != CLIENT_EXIT_NONE) 409 printf("%%exit %s\n", client_exit_message()); 410 else 411 printf("%%exit\n"); 412 fflush(stdout); 413 if (client_flags & CLIENT_CONTROL_WAITEXIT) { 414 setvbuf(stdin, NULL, _IOLBF, 0); 415 for (;;) { 416 linelen = getline(&line, &linesize, stdin); 417 if (linelen <= 1) 418 break; 419 } 420 free(line); 421 } 422 if (client_flags & CLIENT_CONTROLCONTROL) { 423 printf("\033\\"); 424 fflush(stdout); 425 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 426 } 427 } else if (client_exitreason != CLIENT_EXIT_NONE) 428 fprintf(stderr, "%s\n", client_exit_message()); 429 return (client_exitval); 430 } 431 432 /* Send identify messages to server. */ 433 static void 434 client_send_identify(const char *ttynam, const char *cwd, int feat) 435 { 436 const char *s; 437 char **ss; 438 size_t sslen; 439 int fd, flags = client_flags; 440 pid_t pid; 441 442 proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags); 443 444 if ((s = getenv("TERM")) == NULL) 445 s = ""; 446 proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1); 447 proc_send(client_peer, MSG_IDENTIFY_FEATURES, -1, &feat, sizeof feat); 448 449 proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam, 450 strlen(ttynam) + 1); 451 proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1); 452 453 if ((fd = dup(STDIN_FILENO)) == -1) 454 fatal("dup failed"); 455 proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0); 456 if ((fd = dup(STDOUT_FILENO)) == -1) 457 fatal("dup failed"); 458 proc_send(client_peer, MSG_IDENTIFY_STDOUT, fd, NULL, 0); 459 460 pid = getpid(); 461 proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid); 462 463 for (ss = environ; *ss != NULL; ss++) { 464 sslen = strlen(*ss) + 1; 465 if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE) 466 continue; 467 proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen); 468 } 469 470 proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0); 471 } 472 473 /* File write error callback. */ 474 static void 475 client_write_error_callback(__unused struct bufferevent *bev, 476 __unused short what, void *arg) 477 { 478 struct client_file *cf = arg; 479 480 log_debug("write error file %d", cf->stream); 481 482 bufferevent_free(cf->event); 483 cf->event = NULL; 484 485 close(cf->fd); 486 cf->fd = -1; 487 488 if (client_exitflag) 489 client_exit(); 490 } 491 492 /* File write callback. */ 493 static void 494 client_write_callback(__unused struct bufferevent *bev, void *arg) 495 { 496 struct client_file *cf = arg; 497 498 if (cf->closed && EVBUFFER_LENGTH(cf->event->output) == 0) { 499 bufferevent_free(cf->event); 500 close(cf->fd); 501 RB_REMOVE(client_files, &client_files, cf); 502 file_free(cf); 503 } 504 505 if (client_exitflag) 506 client_exit(); 507 } 508 509 /* Open write file. */ 510 static void 511 client_write_open(void *data, size_t datalen) 512 { 513 struct msg_write_open *msg = data; 514 const char *path; 515 struct msg_write_ready reply; 516 struct client_file find, *cf; 517 const int flags = O_NONBLOCK|O_WRONLY|O_CREAT; 518 int error = 0; 519 520 if (datalen < sizeof *msg) 521 fatalx("bad MSG_WRITE_OPEN size"); 522 if (datalen == sizeof *msg) 523 path = "-"; 524 else 525 path = (const char *)(msg + 1); 526 log_debug("open write file %d %s", msg->stream, path); 527 528 find.stream = msg->stream; 529 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 530 cf = file_create(NULL, msg->stream, NULL, NULL); 531 RB_INSERT(client_files, &client_files, cf); 532 } else { 533 error = EBADF; 534 goto reply; 535 } 536 if (cf->closed) { 537 error = EBADF; 538 goto reply; 539 } 540 541 cf->fd = -1; 542 if (msg->fd == -1) 543 cf->fd = open(path, msg->flags|flags, 0644); 544 else { 545 if (msg->fd != STDOUT_FILENO && msg->fd != STDERR_FILENO) 546 errno = EBADF; 547 else { 548 cf->fd = dup(msg->fd); 549 if (~client_flags & CLIENT_CONTROL) 550 close(msg->fd); /* can only be used once */ 551 } 552 } 553 if (cf->fd == -1) { 554 error = errno; 555 goto reply; 556 } 557 558 cf->event = bufferevent_new(cf->fd, NULL, client_write_callback, 559 client_write_error_callback, cf); 560 bufferevent_enable(cf->event, EV_WRITE); 561 goto reply; 562 563 reply: 564 reply.stream = msg->stream; 565 reply.error = error; 566 proc_send(client_peer, MSG_WRITE_READY, -1, &reply, sizeof reply); 567 } 568 569 /* Write to client file. */ 570 static void 571 client_write_data(void *data, size_t datalen) 572 { 573 struct msg_write_data *msg = data; 574 struct client_file find, *cf; 575 size_t size = datalen - sizeof *msg; 576 577 if (datalen < sizeof *msg) 578 fatalx("bad MSG_WRITE size"); 579 find.stream = msg->stream; 580 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 581 fatalx("unknown stream number"); 582 log_debug("write %zu to file %d", size, cf->stream); 583 584 if (cf->event != NULL) 585 bufferevent_write(cf->event, msg + 1, size); 586 } 587 588 /* Close client file. */ 589 static void 590 client_write_close(void *data, size_t datalen) 591 { 592 struct msg_write_close *msg = data; 593 struct client_file find, *cf; 594 595 if (datalen != sizeof *msg) 596 fatalx("bad MSG_WRITE_CLOSE size"); 597 find.stream = msg->stream; 598 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 599 fatalx("unknown stream number"); 600 log_debug("close file %d", cf->stream); 601 602 if (cf->event == NULL || EVBUFFER_LENGTH(cf->event->output) == 0) { 603 if (cf->event != NULL) 604 bufferevent_free(cf->event); 605 if (cf->fd != -1) 606 close(cf->fd); 607 RB_REMOVE(client_files, &client_files, cf); 608 file_free(cf); 609 } 610 } 611 612 /* File read callback. */ 613 static void 614 client_read_callback(__unused struct bufferevent *bev, void *arg) 615 { 616 struct client_file *cf = arg; 617 void *bdata; 618 size_t bsize; 619 struct msg_read_data *msg; 620 size_t msglen; 621 622 msg = xmalloc(sizeof *msg); 623 for (;;) { 624 bdata = EVBUFFER_DATA(cf->event->input); 625 bsize = EVBUFFER_LENGTH(cf->event->input); 626 627 if (bsize == 0) 628 break; 629 if (bsize > MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg) 630 bsize = MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg; 631 log_debug("read %zu from file %d", bsize, cf->stream); 632 633 msglen = (sizeof *msg) + bsize; 634 msg = xrealloc(msg, msglen); 635 msg->stream = cf->stream; 636 memcpy(msg + 1, bdata, bsize); 637 proc_send(client_peer, MSG_READ, -1, msg, msglen); 638 639 evbuffer_drain(cf->event->input, bsize); 640 } 641 free(msg); 642 } 643 644 /* File read error callback. */ 645 static void 646 client_read_error_callback(__unused struct bufferevent *bev, 647 __unused short what, void *arg) 648 { 649 struct client_file *cf = arg; 650 struct msg_read_done msg; 651 652 log_debug("read error file %d", cf->stream); 653 654 msg.stream = cf->stream; 655 msg.error = 0; 656 proc_send(client_peer, MSG_READ_DONE, -1, &msg, sizeof msg); 657 658 bufferevent_free(cf->event); 659 close(cf->fd); 660 RB_REMOVE(client_files, &client_files, cf); 661 file_free(cf); 662 } 663 664 /* Open read file. */ 665 static void 666 client_read_open(void *data, size_t datalen) 667 { 668 struct msg_read_open *msg = data; 669 const char *path; 670 struct msg_read_done reply; 671 struct client_file find, *cf; 672 const int flags = O_NONBLOCK|O_RDONLY; 673 int error; 674 675 if (datalen < sizeof *msg) 676 fatalx("bad MSG_READ_OPEN size"); 677 if (datalen == sizeof *msg) 678 path = "-"; 679 else 680 path = (const char *)(msg + 1); 681 log_debug("open read file %d %s", msg->stream, path); 682 683 find.stream = msg->stream; 684 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 685 cf = file_create(NULL, msg->stream, NULL, NULL); 686 RB_INSERT(client_files, &client_files, cf); 687 } else { 688 error = EBADF; 689 goto reply; 690 } 691 if (cf->closed) { 692 error = EBADF; 693 goto reply; 694 } 695 696 cf->fd = -1; 697 if (msg->fd == -1) 698 cf->fd = open(path, flags); 699 else { 700 if (msg->fd != STDIN_FILENO) 701 errno = EBADF; 702 else { 703 cf->fd = dup(msg->fd); 704 if (~client_flags & CLIENT_CONTROL) 705 close(msg->fd); /* can only be used once */ 706 } 707 } 708 if (cf->fd == -1) { 709 error = errno; 710 goto reply; 711 } 712 713 cf->event = bufferevent_new(cf->fd, client_read_callback, NULL, 714 client_read_error_callback, cf); 715 bufferevent_enable(cf->event, EV_READ); 716 return; 717 718 reply: 719 reply.stream = msg->stream; 720 reply.error = error; 721 proc_send(client_peer, MSG_READ_DONE, -1, &reply, sizeof reply); 722 } 723 724 /* Run command in shell; used for -c. */ 725 static __dead void 726 client_exec(const char *shell, const char *shellcmd) 727 { 728 const char *name, *ptr; 729 char *argv0; 730 731 log_debug("shell %s, command %s", shell, shellcmd); 732 733 ptr = strrchr(shell, '/'); 734 if (ptr != NULL && *(ptr + 1) != '\0') 735 name = ptr + 1; 736 else 737 name = shell; 738 if (client_flags & CLIENT_LOGIN) 739 xasprintf(&argv0, "-%s", name); 740 else 741 xasprintf(&argv0, "%s", name); 742 setenv("SHELL", shell, 1); 743 744 proc_clear_signals(client_proc, 1); 745 746 setblocking(STDIN_FILENO, 1); 747 setblocking(STDOUT_FILENO, 1); 748 setblocking(STDERR_FILENO, 1); 749 closefrom(STDERR_FILENO + 1); 750 751 execl(shell, argv0, "-c", shellcmd, (char *) NULL); 752 fatal("execl failed"); 753 } 754 755 /* Callback to handle signals in the client. */ 756 static void 757 client_signal(int sig) 758 { 759 struct sigaction sigact; 760 int status; 761 762 if (sig == SIGCHLD) 763 waitpid(WAIT_ANY, &status, WNOHANG); 764 else if (!client_attached) { 765 if (sig == SIGTERM) 766 proc_exit(client_proc); 767 } else { 768 switch (sig) { 769 case SIGHUP: 770 client_exitreason = CLIENT_EXIT_LOST_TTY; 771 client_exitval = 1; 772 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 773 break; 774 case SIGTERM: 775 client_exitreason = CLIENT_EXIT_TERMINATED; 776 client_exitval = 1; 777 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 778 break; 779 case SIGWINCH: 780 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 781 break; 782 case SIGCONT: 783 memset(&sigact, 0, sizeof sigact); 784 sigemptyset(&sigact.sa_mask); 785 sigact.sa_flags = SA_RESTART; 786 sigact.sa_handler = SIG_IGN; 787 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 788 fatal("sigaction failed"); 789 proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0); 790 break; 791 } 792 } 793 } 794 795 /* Callback for client read events. */ 796 static void 797 client_dispatch(struct imsg *imsg, __unused void *arg) 798 { 799 if (imsg == NULL) { 800 client_exitreason = CLIENT_EXIT_LOST_SERVER; 801 client_exitval = 1; 802 proc_exit(client_proc); 803 return; 804 } 805 806 if (client_attached) 807 client_dispatch_attached(imsg); 808 else 809 client_dispatch_wait(imsg); 810 } 811 812 /* Process an exit message. */ 813 static void 814 client_dispatch_exit_message(char *data, size_t datalen) 815 { 816 int retval; 817 818 if (datalen < sizeof retval && datalen != 0) 819 fatalx("bad MSG_EXIT size"); 820 821 if (datalen >= sizeof retval) { 822 memcpy(&retval, data, sizeof retval); 823 client_exitval = retval; 824 } 825 826 if (datalen > sizeof retval) { 827 datalen -= sizeof retval; 828 data += sizeof retval; 829 830 client_exitmessage = xmalloc(datalen); 831 memcpy(client_exitmessage, data, datalen); 832 client_exitmessage[datalen - 1] = '\0'; 833 834 client_exitreason = CLIENT_EXIT_MESSAGE_PROVIDED; 835 } 836 } 837 838 /* Dispatch imsgs when in wait state (before MSG_READY). */ 839 static void 840 client_dispatch_wait(struct imsg *imsg) 841 { 842 char *data; 843 ssize_t datalen; 844 static int pledge_applied; 845 846 /* 847 * "sendfd" is no longer required once all of the identify messages 848 * have been sent. We know the server won't send us anything until that 849 * point (because we don't ask it to), so we can drop "sendfd" once we 850 * get the first message from the server. 851 */ 852 if (!pledge_applied) { 853 if (pledge( 854 "stdio rpath wpath cpath unix proc exec tty", 855 NULL) != 0) 856 fatal("pledge failed"); 857 pledge_applied = 1; 858 } 859 860 data = imsg->data; 861 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 862 863 switch (imsg->hdr.type) { 864 case MSG_EXIT: 865 case MSG_SHUTDOWN: 866 client_dispatch_exit_message(data, datalen); 867 client_exitflag = 1; 868 client_exit(); 869 break; 870 case MSG_READY: 871 if (datalen != 0) 872 fatalx("bad MSG_READY size"); 873 874 client_attached = 1; 875 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 876 break; 877 case MSG_VERSION: 878 if (datalen != 0) 879 fatalx("bad MSG_VERSION size"); 880 881 fprintf(stderr, "protocol version mismatch " 882 "(client %d, server %u)\n", PROTOCOL_VERSION, 883 imsg->hdr.peerid & 0xff); 884 client_exitval = 1; 885 proc_exit(client_proc); 886 break; 887 case MSG_FLAGS: 888 if (datalen != sizeof client_flags) 889 fatalx("bad MSG_FLAGS string"); 890 891 memcpy(&client_flags, data, sizeof client_flags); 892 log_debug("new flags are %#llx", client_flags); 893 break; 894 case MSG_SHELL: 895 if (datalen == 0 || data[datalen - 1] != '\0') 896 fatalx("bad MSG_SHELL string"); 897 898 client_exec(data, shell_command); 899 /* NOTREACHED */ 900 case MSG_DETACH: 901 case MSG_DETACHKILL: 902 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 903 break; 904 case MSG_EXITED: 905 proc_exit(client_proc); 906 break; 907 case MSG_READ_OPEN: 908 client_read_open(data, datalen); 909 break; 910 case MSG_WRITE_OPEN: 911 client_write_open(data, datalen); 912 break; 913 case MSG_WRITE: 914 client_write_data(data, datalen); 915 break; 916 case MSG_WRITE_CLOSE: 917 client_write_close(data, datalen); 918 break; 919 case MSG_OLDSTDERR: 920 case MSG_OLDSTDIN: 921 case MSG_OLDSTDOUT: 922 fprintf(stderr, "server version is too old for client\n"); 923 proc_exit(client_proc); 924 break; 925 } 926 } 927 928 /* Dispatch imsgs in attached state (after MSG_READY). */ 929 static void 930 client_dispatch_attached(struct imsg *imsg) 931 { 932 struct sigaction sigact; 933 char *data; 934 ssize_t datalen; 935 936 data = imsg->data; 937 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 938 939 switch (imsg->hdr.type) { 940 case MSG_FLAGS: 941 if (datalen != sizeof client_flags) 942 fatalx("bad MSG_FLAGS string"); 943 944 memcpy(&client_flags, data, sizeof client_flags); 945 log_debug("new flags are %#llx", client_flags); 946 break; 947 case MSG_DETACH: 948 case MSG_DETACHKILL: 949 if (datalen == 0 || data[datalen - 1] != '\0') 950 fatalx("bad MSG_DETACH string"); 951 952 client_exitsession = xstrdup(data); 953 client_exittype = imsg->hdr.type; 954 if (imsg->hdr.type == MSG_DETACHKILL) 955 client_exitreason = CLIENT_EXIT_DETACHED_HUP; 956 else 957 client_exitreason = CLIENT_EXIT_DETACHED; 958 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 959 break; 960 case MSG_EXEC: 961 if (datalen == 0 || data[datalen - 1] != '\0' || 962 strlen(data) + 1 == (size_t)datalen) 963 fatalx("bad MSG_EXEC string"); 964 client_execcmd = xstrdup(data); 965 client_execshell = xstrdup(data + strlen(data) + 1); 966 967 client_exittype = imsg->hdr.type; 968 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 969 break; 970 case MSG_EXIT: 971 client_dispatch_exit_message(data, datalen); 972 if (client_exitreason == CLIENT_EXIT_NONE) 973 client_exitreason = CLIENT_EXIT_EXITED; 974 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 975 break; 976 case MSG_EXITED: 977 if (datalen != 0) 978 fatalx("bad MSG_EXITED size"); 979 980 proc_exit(client_proc); 981 break; 982 case MSG_SHUTDOWN: 983 if (datalen != 0) 984 fatalx("bad MSG_SHUTDOWN size"); 985 986 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 987 client_exitreason = CLIENT_EXIT_SERVER_EXITED; 988 client_exitval = 1; 989 break; 990 case MSG_SUSPEND: 991 if (datalen != 0) 992 fatalx("bad MSG_SUSPEND size"); 993 994 memset(&sigact, 0, sizeof sigact); 995 sigemptyset(&sigact.sa_mask); 996 sigact.sa_flags = SA_RESTART; 997 sigact.sa_handler = SIG_DFL; 998 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 999 fatal("sigaction failed"); 1000 kill(getpid(), SIGTSTP); 1001 break; 1002 case MSG_LOCK: 1003 if (datalen == 0 || data[datalen - 1] != '\0') 1004 fatalx("bad MSG_LOCK string"); 1005 1006 system(data); 1007 proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0); 1008 break; 1009 } 1010 } 1011