1 /* $OpenBSD: proc.c,v 1.22 2022/05/30 12:48:57 nicm Exp $ */ 2 3 /* 4 * Copyright (c) 2015 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/queue.h> 21 #include <sys/socket.h> 22 #include <sys/uio.h> 23 #include <sys/utsname.h> 24 25 #include <errno.h> 26 #include <event.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 struct tmuxproc { 36 const char *name; 37 int exit; 38 39 void (*signalcb)(int); 40 41 struct event ev_sigint; 42 struct event ev_sighup; 43 struct event ev_sigchld; 44 struct event ev_sigcont; 45 struct event ev_sigterm; 46 struct event ev_sigusr1; 47 struct event ev_sigusr2; 48 struct event ev_sigwinch; 49 50 TAILQ_HEAD(, tmuxpeer) peers; 51 }; 52 53 struct tmuxpeer { 54 struct tmuxproc *parent; 55 56 struct imsgbuf ibuf; 57 struct event event; 58 uid_t uid; 59 60 int flags; 61 #define PEER_BAD 0x1 62 63 void (*dispatchcb)(struct imsg *, void *); 64 void *arg; 65 66 TAILQ_ENTRY(tmuxpeer) entry; 67 }; 68 69 static int peer_check_version(struct tmuxpeer *, struct imsg *); 70 static void proc_update_event(struct tmuxpeer *); 71 72 static void 73 proc_event_cb(__unused int fd, short events, void *arg) 74 { 75 struct tmuxpeer *peer = arg; 76 ssize_t n; 77 struct imsg imsg; 78 79 if (!(peer->flags & PEER_BAD) && (events & EV_READ)) { 80 if (((n = imsg_read(&peer->ibuf)) == -1 && errno != EAGAIN) || 81 n == 0) { 82 peer->dispatchcb(NULL, peer->arg); 83 return; 84 } 85 for (;;) { 86 if ((n = imsg_get(&peer->ibuf, &imsg)) == -1) { 87 peer->dispatchcb(NULL, peer->arg); 88 return; 89 } 90 if (n == 0) 91 break; 92 log_debug("peer %p message %d", peer, imsg.hdr.type); 93 94 if (peer_check_version(peer, &imsg) != 0) { 95 if (imsg.fd != -1) 96 close(imsg.fd); 97 imsg_free(&imsg); 98 break; 99 } 100 101 peer->dispatchcb(&imsg, peer->arg); 102 imsg_free(&imsg); 103 } 104 } 105 106 if (events & EV_WRITE) { 107 if (msgbuf_write(&peer->ibuf.w) <= 0 && errno != EAGAIN) { 108 peer->dispatchcb(NULL, peer->arg); 109 return; 110 } 111 } 112 113 if ((peer->flags & PEER_BAD) && peer->ibuf.w.queued == 0) { 114 peer->dispatchcb(NULL, peer->arg); 115 return; 116 } 117 118 proc_update_event(peer); 119 } 120 121 static void 122 proc_signal_cb(int signo, __unused short events, void *arg) 123 { 124 struct tmuxproc *tp = arg; 125 126 tp->signalcb(signo); 127 } 128 129 static int 130 peer_check_version(struct tmuxpeer *peer, struct imsg *imsg) 131 { 132 int version; 133 134 version = imsg->hdr.peerid & 0xff; 135 if (imsg->hdr.type != MSG_VERSION && version != PROTOCOL_VERSION) { 136 log_debug("peer %p bad version %d", peer, version); 137 138 proc_send(peer, MSG_VERSION, -1, NULL, 0); 139 peer->flags |= PEER_BAD; 140 141 return (-1); 142 } 143 return (0); 144 } 145 146 static void 147 proc_update_event(struct tmuxpeer *peer) 148 { 149 short events; 150 151 event_del(&peer->event); 152 153 events = EV_READ; 154 if (peer->ibuf.w.queued > 0) 155 events |= EV_WRITE; 156 event_set(&peer->event, peer->ibuf.fd, events, proc_event_cb, peer); 157 158 event_add(&peer->event, NULL); 159 } 160 161 int 162 proc_send(struct tmuxpeer *peer, enum msgtype type, int fd, const void *buf, 163 size_t len) 164 { 165 struct imsgbuf *ibuf = &peer->ibuf; 166 void *vp = (void *)buf; 167 int retval; 168 169 if (peer->flags & PEER_BAD) 170 return (-1); 171 log_debug("sending message %d to peer %p (%zu bytes)", type, peer, len); 172 173 retval = imsg_compose(ibuf, type, PROTOCOL_VERSION, -1, fd, vp, len); 174 if (retval != 1) 175 return (-1); 176 proc_update_event(peer); 177 return (0); 178 } 179 180 struct tmuxproc * 181 proc_start(const char *name) 182 { 183 struct tmuxproc *tp; 184 struct utsname u; 185 186 log_open(name); 187 setproctitle("%s (%s)", name, socket_path); 188 189 if (uname(&u) < 0) 190 memset(&u, 0, sizeof u); 191 192 log_debug("%s started (%ld): version %s, socket %s, protocol %d", name, 193 (long)getpid(), getversion(), socket_path, PROTOCOL_VERSION); 194 log_debug("on %s %s %s; libevent %s (%s)", u.sysname, u.release, 195 u.version, event_get_version(), event_get_method()); 196 197 tp = xcalloc(1, sizeof *tp); 198 tp->name = xstrdup(name); 199 TAILQ_INIT(&tp->peers); 200 201 return (tp); 202 } 203 204 void 205 proc_loop(struct tmuxproc *tp, int (*loopcb)(void)) 206 { 207 log_debug("%s loop enter", tp->name); 208 do 209 event_loop(EVLOOP_ONCE); 210 while (!tp->exit && (loopcb == NULL || !loopcb ())); 211 log_debug("%s loop exit", tp->name); 212 } 213 214 void 215 proc_exit(struct tmuxproc *tp) 216 { 217 struct tmuxpeer *peer; 218 219 TAILQ_FOREACH(peer, &tp->peers, entry) 220 imsg_flush(&peer->ibuf); 221 tp->exit = 1; 222 } 223 224 void 225 proc_set_signals(struct tmuxproc *tp, void (*signalcb)(int)) 226 { 227 struct sigaction sa; 228 229 tp->signalcb = signalcb; 230 231 memset(&sa, 0, sizeof sa); 232 sigemptyset(&sa.sa_mask); 233 sa.sa_flags = SA_RESTART; 234 sa.sa_handler = SIG_IGN; 235 236 sigaction(SIGPIPE, &sa, NULL); 237 sigaction(SIGTSTP, &sa, NULL); 238 sigaction(SIGTTIN, &sa, NULL); 239 sigaction(SIGTTOU, &sa, NULL); 240 sigaction(SIGQUIT, &sa, NULL); 241 242 signal_set(&tp->ev_sigint, SIGINT, proc_signal_cb, tp); 243 signal_add(&tp->ev_sigint, NULL); 244 signal_set(&tp->ev_sighup, SIGHUP, proc_signal_cb, tp); 245 signal_add(&tp->ev_sighup, NULL); 246 signal_set(&tp->ev_sigchld, SIGCHLD, proc_signal_cb, tp); 247 signal_add(&tp->ev_sigchld, NULL); 248 signal_set(&tp->ev_sigcont, SIGCONT, proc_signal_cb, tp); 249 signal_add(&tp->ev_sigcont, NULL); 250 signal_set(&tp->ev_sigterm, SIGTERM, proc_signal_cb, tp); 251 signal_add(&tp->ev_sigterm, NULL); 252 signal_set(&tp->ev_sigusr1, SIGUSR1, proc_signal_cb, tp); 253 signal_add(&tp->ev_sigusr1, NULL); 254 signal_set(&tp->ev_sigusr2, SIGUSR2, proc_signal_cb, tp); 255 signal_add(&tp->ev_sigusr2, NULL); 256 signal_set(&tp->ev_sigwinch, SIGWINCH, proc_signal_cb, tp); 257 signal_add(&tp->ev_sigwinch, NULL); 258 } 259 260 void 261 proc_clear_signals(struct tmuxproc *tp, int defaults) 262 { 263 struct sigaction sa; 264 265 memset(&sa, 0, sizeof sa); 266 sigemptyset(&sa.sa_mask); 267 sa.sa_flags = SA_RESTART; 268 sa.sa_handler = SIG_DFL; 269 270 sigaction(SIGPIPE, &sa, NULL); 271 sigaction(SIGTSTP, &sa, NULL); 272 273 signal_del(&tp->ev_sigint); 274 signal_del(&tp->ev_sighup); 275 signal_del(&tp->ev_sigchld); 276 signal_del(&tp->ev_sigcont); 277 signal_del(&tp->ev_sigterm); 278 signal_del(&tp->ev_sigusr1); 279 signal_del(&tp->ev_sigusr2); 280 signal_del(&tp->ev_sigwinch); 281 282 if (defaults) { 283 sigaction(SIGINT, &sa, NULL); 284 sigaction(SIGQUIT, &sa, NULL); 285 sigaction(SIGHUP, &sa, NULL); 286 sigaction(SIGCHLD, &sa, NULL); 287 sigaction(SIGCONT, &sa, NULL); 288 sigaction(SIGTERM, &sa, NULL); 289 sigaction(SIGUSR1, &sa, NULL); 290 sigaction(SIGUSR2, &sa, NULL); 291 sigaction(SIGWINCH, &sa, NULL); 292 } 293 } 294 295 struct tmuxpeer * 296 proc_add_peer(struct tmuxproc *tp, int fd, 297 void (*dispatchcb)(struct imsg *, void *), void *arg) 298 { 299 struct tmuxpeer *peer; 300 gid_t gid; 301 302 peer = xcalloc(1, sizeof *peer); 303 peer->parent = tp; 304 305 peer->dispatchcb = dispatchcb; 306 peer->arg = arg; 307 308 imsg_init(&peer->ibuf, fd); 309 event_set(&peer->event, fd, EV_READ, proc_event_cb, peer); 310 311 if (getpeereid(fd, &peer->uid, &gid) != 0) 312 peer->uid = (uid_t)-1; 313 314 log_debug("add peer %p: %d (%p)", peer, fd, arg); 315 TAILQ_INSERT_TAIL(&tp->peers, peer, entry); 316 317 proc_update_event(peer); 318 return (peer); 319 } 320 321 void 322 proc_remove_peer(struct tmuxpeer *peer) 323 { 324 TAILQ_REMOVE(&peer->parent->peers, peer, entry); 325 log_debug("remove peer %p", peer); 326 327 event_del(&peer->event); 328 imsg_clear(&peer->ibuf); 329 330 close(peer->ibuf.fd); 331 free(peer); 332 } 333 334 void 335 proc_kill_peer(struct tmuxpeer *peer) 336 { 337 peer->flags |= PEER_BAD; 338 } 339 340 void 341 proc_flush_peer(struct tmuxpeer *peer) 342 { 343 imsg_flush(&peer->ibuf); 344 } 345 346 void 347 proc_toggle_log(struct tmuxproc *tp) 348 { 349 log_toggle(tp->name); 350 } 351 352 pid_t 353 proc_fork_and_daemon(int *fd) 354 { 355 pid_t pid; 356 int pair[2]; 357 358 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0) 359 fatal("socketpair failed"); 360 switch (pid = fork()) { 361 case -1: 362 fatal("fork failed"); 363 case 0: 364 close(pair[0]); 365 *fd = pair[1]; 366 if (daemon(1, 0) != 0) 367 fatal("daemon failed"); 368 return (0); 369 default: 370 close(pair[1]); 371 *fd = pair[0]; 372 return (pid); 373 } 374 } 375 376 uid_t 377 proc_get_peer_uid(struct tmuxpeer *peer) 378 { 379 return (peer->uid); 380 } 381