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/socket.h>
  21 #include <sys/uio.h>
  22 #include <sys/utsname.h>
  23
  24 #include <errno.h>
  25 #include <signal.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29
  30 #if defined(HAVE_NCURSES_H)
  31 #include <ncurses.h>
  32 #endif
  33
  34 #include "tmux.h"
  35
  36 struct tmuxproc {
  37         const char       *name;
  38         int               exit;
  39
  40         void            (*signalcb)(int);
  41
  42         struct event      ev_sigint;
  43         struct event      ev_sighup;
  44         struct event      ev_sigchld;
  45         struct event      ev_sigcont;
  46         struct event      ev_sigterm;
  47         struct event      ev_sigusr1;
  48         struct event      ev_sigusr2;
  49         struct event      ev_sigwinch;
  50
  51         TAILQ_HEAD(, tmuxpeer) peers;
  52 };
  53
  54 struct tmuxpeer {
  55         struct tmuxproc *parent;
  56
  57         struct imsgbuf   ibuf;
  58         struct event     event;
  59         uid_t            uid;
  60
  61         int              flags;
  62 #define PEER_BAD 0x1
  63
  64         void            (*dispatchcb)(struct imsg *, void *);
  65         void             *arg;
  66
  67         TAILQ_ENTRY(tmuxpeer) entry;
  68 };
  69
  70 static int      peer_check_version(struct tmuxpeer *, struct imsg *);
  71 static void     proc_update_event(struct tmuxpeer *);
  72
  73 static void
  74 proc_event_cb(__unused int fd, short events, void *arg)
  75 {
  76         struct tmuxpeer *peer = arg;
  77         ssize_t          n;
  78         struct imsg      imsg;
  79
  80         if (!(peer->flags & PEER_BAD) && (events & EV_READ)) {
  81                 if (imsgbuf_read(&peer->ibuf) != 1) {
  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                                 imsg_free(&imsg);
  96                                 break;
  97                         }
  98
  99                         peer->dispatchcb(&imsg, peer->arg);
 100                         imsg_free(&imsg);
 101                 }
 102         }
 103
 104         if (events & EV_WRITE) {
 105                 if (imsgbuf_write(&peer->ibuf) == -1) {
 106                         peer->dispatchcb(NULL, peer->arg);
 107                         return;
 108                 }
 109         }
 110
 111         if ((peer->flags & PEER_BAD) && imsgbuf_queuelen(&peer->ibuf) == 0) {
 112                 peer->dispatchcb(NULL, peer->arg);
 113                 return;
 114         }
 115
 116         proc_update_event(peer);
 117 }
 118
 119 static void
 120 proc_signal_cb(int signo, __unused short events, void *arg)
 121 {
 122         struct tmuxproc *tp = arg;
 123
 124         tp->signalcb(signo);
 125 }
 126
 127 static int
 128 peer_check_version(struct tmuxpeer *peer, struct imsg *imsg)
 129 {
 130         int     version;
 131
 132         version = imsg->hdr.peerid & 0xff;
 133         if (imsg->hdr.type != MSG_VERSION && version != PROTOCOL_VERSION) {
 134                 log_debug("peer %p bad version %d", peer, version);
 135
 136                 proc_send(peer, MSG_VERSION, -1, NULL, 0);
 137                 peer->flags |= PEER_BAD;
 138
 139                 return (-1);
 140         }
 141         return (0);
 142 }
 143
 144 static void
 145 proc_update_event(struct tmuxpeer *peer)
 146 {
 147         short   events;
 148
 149         event_del(&peer->event);
 150
 151         events = EV_READ;
 152         if (imsgbuf_queuelen(&peer->ibuf) > 0)
 153                 events |= EV_WRITE;
 154         event_set(&peer->event, peer->ibuf.fd, events, proc_event_cb, peer);
 155
 156         event_add(&peer->event, NULL);
 157 }
 158
 159 int
 160 proc_send(struct tmuxpeer *peer, enum msgtype type, int fd, const void *buf,
 161     size_t len)
 162 {
 163         struct imsgbuf  *ibuf = &peer->ibuf;
 164         void            *vp = (void *)buf;
 165         int              retval;
 166
 167         if (peer->flags & PEER_BAD)
 168                 return (-1);
 169         log_debug("sending message %d to peer %p (%zu bytes)", type, peer, len);
 170
 171         retval = imsg_compose(ibuf, type, PROTOCOL_VERSION, -1, fd, vp, len);
 172         if (retval != 1)
 173                 return (-1);
 174         proc_update_event(peer);
 175         return (0);
 176 }
 177
 178 struct tmuxproc *
 179 proc_start(const char *name)
 180 {
 181         struct tmuxproc *tp;
 182         struct utsname   u;
 183
 184         log_open(name);
 185         setproctitle("%s (%s)", name, socket_path);
 186
 187         if (uname(&u) < 0)
 188                 memset(&u, 0, sizeof u);
 189
 190         log_debug("%s started (%ld): version %s, socket %s, protocol %d", name,
 191             (long)getpid(), getversion(), socket_path, PROTOCOL_VERSION);
 192         log_debug("on %s %s %s", u.sysname, u.release, u.version);
 193         log_debug("using libevent %s %s", event_get_version(), event_get_method());
 194 #ifdef HAVE_UTF8PROC
 195         log_debug("using utf8proc %s", utf8proc_version());
 196 #endif
 197 #ifdef NCURSES_VERSION
 198         log_debug("using ncurses %s %06u", NCURSES_VERSION, NCURSES_VERSION_PATCH);
 199 #endif
 200
 201         tp = xcalloc(1, sizeof *tp);
 202         tp->name = xstrdup(name);
 203         TAILQ_INIT(&tp->peers);
 204
 205         return (tp);
 206 }
 207
 208 void
 209 proc_loop(struct tmuxproc *tp, int (*loopcb)(void))
 210 {
 211         log_debug("%s loop enter", tp->name);
 212         do
 213                 event_loop(EVLOOP_ONCE);
 214         while (!tp->exit && (loopcb == NULL || !loopcb ()));
 215         log_debug("%s loop exit", tp->name);
 216 }
 217
 218 void
 219 proc_exit(struct tmuxproc *tp)
 220 {
 221         struct tmuxpeer *peer;
 222
 223         TAILQ_FOREACH(peer, &tp->peers, entry)
 224             imsgbuf_flush(&peer->ibuf);
 225         tp->exit = 1;
 226 }
 227
 228 void
 229 proc_set_signals(struct tmuxproc *tp, void (*signalcb)(int))
 230 {
 231         struct sigaction        sa;
 232
 233         tp->signalcb = signalcb;
 234
 235         memset(&sa, 0, sizeof sa);
 236         sigemptyset(&sa.sa_mask);
 237         sa.sa_flags = SA_RESTART;
 238         sa.sa_handler = SIG_IGN;
 239
 240         sigaction(SIGPIPE, &sa, NULL);
 241         sigaction(SIGTSTP, &sa, NULL);
 242         sigaction(SIGTTIN, &sa, NULL);
 243         sigaction(SIGTTOU, &sa, NULL);
 244         sigaction(SIGQUIT, &sa, NULL);
 245
 246         signal_set(&tp->ev_sigint, SIGINT, proc_signal_cb, tp);
 247         signal_add(&tp->ev_sigint, NULL);
 248         signal_set(&tp->ev_sighup, SIGHUP, proc_signal_cb, tp);
 249         signal_add(&tp->ev_sighup, NULL);
 250         signal_set(&tp->ev_sigchld, SIGCHLD, proc_signal_cb, tp);
 251         signal_add(&tp->ev_sigchld, NULL);
 252         signal_set(&tp->ev_sigcont, SIGCONT, proc_signal_cb, tp);
 253         signal_add(&tp->ev_sigcont, NULL);
 254         signal_set(&tp->ev_sigterm, SIGTERM, proc_signal_cb, tp);
 255         signal_add(&tp->ev_sigterm, NULL);
 256         signal_set(&tp->ev_sigusr1, SIGUSR1, proc_signal_cb, tp);
 257         signal_add(&tp->ev_sigusr1, NULL);
 258         signal_set(&tp->ev_sigusr2, SIGUSR2, proc_signal_cb, tp);
 259         signal_add(&tp->ev_sigusr2, NULL);
 260         signal_set(&tp->ev_sigwinch, SIGWINCH, proc_signal_cb, tp);
 261         signal_add(&tp->ev_sigwinch, NULL);
 262 }
 263
 264 void
 265 proc_clear_signals(struct tmuxproc *tp, int defaults)
 266 {
 267         struct sigaction        sa;
 268
 269         memset(&sa, 0, sizeof sa);
 270         sigemptyset(&sa.sa_mask);
 271         sa.sa_flags = SA_RESTART;
 272         sa.sa_handler = SIG_DFL;
 273
 274         sigaction(SIGPIPE, &sa, NULL);
 275         sigaction(SIGTSTP, &sa, NULL);
 276
 277         signal_del(&tp->ev_sigint);
 278         signal_del(&tp->ev_sighup);
 279         signal_del(&tp->ev_sigchld);
 280         signal_del(&tp->ev_sigcont);
 281         signal_del(&tp->ev_sigterm);
 282         signal_del(&tp->ev_sigusr1);
 283         signal_del(&tp->ev_sigusr2);
 284         signal_del(&tp->ev_sigwinch);
 285
 286         if (defaults) {
 287                 sigaction(SIGINT, &sa, NULL);
 288                 sigaction(SIGQUIT, &sa, NULL);
 289                 sigaction(SIGHUP, &sa, NULL);
 290                 sigaction(SIGCHLD, &sa, NULL);
 291                 sigaction(SIGCONT, &sa, NULL);
 292                 sigaction(SIGTERM, &sa, NULL);
 293                 sigaction(SIGUSR1, &sa, NULL);
 294                 sigaction(SIGUSR2, &sa, NULL);
 295                 sigaction(SIGWINCH, &sa, NULL);
 296         }
 297 }
 298
 299 struct tmuxpeer *
 300 proc_add_peer(struct tmuxproc *tp, int fd,
 301     void (*dispatchcb)(struct imsg *, void *), void *arg)
 302 {
 303         struct tmuxpeer *peer;
 304         gid_t            gid;
 305
 306         peer = xcalloc(1, sizeof *peer);
 307         peer->parent = tp;
 308
 309         peer->dispatchcb = dispatchcb;
 310         peer->arg = arg;
 311
 312         if (imsgbuf_init(&peer->ibuf, fd) == -1)
 313                 fatal("imsgbuf_init");
 314         imsgbuf_allow_fdpass(&peer->ibuf);
 315         event_set(&peer->event, fd, EV_READ, proc_event_cb, peer);
 316
 317         if (getpeereid(fd, &peer->uid, &gid) != 0)
 318                 peer->uid = (uid_t)-1;
 319
 320         log_debug("add peer %p: %d (%p)", peer, fd, arg);
 321         TAILQ_INSERT_TAIL(&tp->peers, peer, entry);
 322
 323         proc_update_event(peer);
 324         return (peer);
 325 }
 326
 327 void
 328 proc_remove_peer(struct tmuxpeer *peer)
 329 {
 330         TAILQ_REMOVE(&peer->parent->peers, peer, entry);
 331         log_debug("remove peer %p", peer);
 332
 333         event_del(&peer->event);
 334         imsgbuf_clear(&peer->ibuf);
 335
 336         close(peer->ibuf.fd);
 337         free(peer);
 338 }
 339
 340 void
 341 proc_kill_peer(struct tmuxpeer *peer)
 342 {
 343         peer->flags |= PEER_BAD;
 344 }
 345
 346 void
 347 proc_flush_peer(struct tmuxpeer *peer)
 348 {
 349         imsgbuf_flush(&peer->ibuf);
 350 }
 351
 352 void
 353 proc_toggle_log(struct tmuxproc *tp)
 354 {
 355         log_toggle(tp->name);
 356 }
 357
 358 pid_t
 359 proc_fork_and_daemon(int *fd)
 360 {
 361         pid_t   pid;
 362         int     pair[2];
 363
 364         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
 365                 fatal("socketpair failed");
 366         switch (pid = fork()) {
 367         case -1:
 368                 fatal("fork failed");
 369         case 0:
 370                 close(pair[0]);
 371                 *fd = pair[1];
 372                 if (daemon(1, 0) != 0)
 373                         fatal("daemon failed");
 374                 return (0);
 375         default:
 376                 close(pair[1]);
 377                 *fd = pair[0];
 378                 return (pid);
 379         }
 380 }
 381
 382 uid_t
 383 proc_get_peer_uid(struct tmuxpeer *peer)
 384 {
 385         return (peer->uid);
 386 }