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                                 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 }