proc.c

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