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 (((n = imsg_read(&peer->ibuf)) == -1 && errno != EAGAIN) ||
  82                     n == 0) {
  83                         peer->dispatchcb(NULL, peer->arg);
  84                         return;
  85                 }
  86                 for (;;) {
  87                         if ((n = imsg_get(&peer->ibuf, &imsg)) == -1) {
  88                                 peer->dispatchcb(NULL, peer->arg);
  89                                 return;
  90                         }
  91                         if (n == 0)
  92                                 break;
  93                         log_debug("peer %p message %d", peer, imsg.hdr.type);
  94
  95                         if (peer_check_version(peer, &imsg) != 0) {
  96                                 if (imsg.fd != -1)
  97                                         close(imsg.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", u.sysname, u.release, u.version);
 196         log_debug("using libevent %s (%s)"
 197 #ifdef HAVE_UTF8PROC
 198             "; utf8proc %s"
 199 #endif
 200 #ifdef NCURSES_VERSION
 201             "; ncurses " NCURSES_VERSION
 202 #endif
 203             , event_get_version(), event_get_method()
 204 #ifdef HAVE_UTF8PROC
 205             , utf8proc_version ()
 206 #endif
 207         );
 208
 209         tp = xcalloc(1, sizeof *tp);
 210         tp->name = xstrdup(name);
 211         TAILQ_INIT(&tp->peers);
 212
 213         return (tp);
 214 }
 215
 216 void
 217 proc_loop(struct tmuxproc *tp, int (*loopcb)(void))
 218 {
 219         log_debug("%s loop enter", tp->name);
 220         do
 221                 event_loop(EVLOOP_ONCE);
 222         while (!tp->exit && (loopcb == NULL || !loopcb ()));
 223         log_debug("%s loop exit", tp->name);
 224 }
 225
 226 void
 227 proc_exit(struct tmuxproc *tp)
 228 {
 229         struct tmuxpeer *peer;
 230
 231         TAILQ_FOREACH(peer, &tp->peers, entry)
 232             imsg_flush(&peer->ibuf);
 233         tp->exit = 1;
 234 }
 235
 236 void
 237 proc_set_signals(struct tmuxproc *tp, void (*signalcb)(int))
 238 {
 239         struct sigaction        sa;
 240
 241         tp->signalcb = signalcb;
 242
 243         memset(&sa, 0, sizeof sa);
 244         sigemptyset(&sa.sa_mask);
 245         sa.sa_flags = SA_RESTART;
 246         sa.sa_handler = SIG_IGN;
 247
 248         sigaction(SIGPIPE, &sa, NULL);
 249         sigaction(SIGTSTP, &sa, NULL);
 250         sigaction(SIGTTIN, &sa, NULL);
 251         sigaction(SIGTTOU, &sa, NULL);
 252         sigaction(SIGQUIT, &sa, NULL);
 253
 254         signal_set(&tp->ev_sigint, SIGINT, proc_signal_cb, tp);
 255         signal_add(&tp->ev_sigint, NULL);
 256         signal_set(&tp->ev_sighup, SIGHUP, proc_signal_cb, tp);
 257         signal_add(&tp->ev_sighup, NULL);
 258         signal_set(&tp->ev_sigchld, SIGCHLD, proc_signal_cb, tp);
 259         signal_add(&tp->ev_sigchld, NULL);
 260         signal_set(&tp->ev_sigcont, SIGCONT, proc_signal_cb, tp);
 261         signal_add(&tp->ev_sigcont, NULL);
 262         signal_set(&tp->ev_sigterm, SIGTERM, proc_signal_cb, tp);
 263         signal_add(&tp->ev_sigterm, NULL);
 264         signal_set(&tp->ev_sigusr1, SIGUSR1, proc_signal_cb, tp);
 265         signal_add(&tp->ev_sigusr1, NULL);
 266         signal_set(&tp->ev_sigusr2, SIGUSR2, proc_signal_cb, tp);
 267         signal_add(&tp->ev_sigusr2, NULL);
 268         signal_set(&tp->ev_sigwinch, SIGWINCH, proc_signal_cb, tp);
 269         signal_add(&tp->ev_sigwinch, NULL);
 270 }
 271
 272 void
 273 proc_clear_signals(struct tmuxproc *tp, int defaults)
 274 {
 275         struct sigaction        sa;
 276
 277         memset(&sa, 0, sizeof sa);
 278         sigemptyset(&sa.sa_mask);
 279         sa.sa_flags = SA_RESTART;
 280         sa.sa_handler = SIG_DFL;
 281
 282         sigaction(SIGPIPE, &sa, NULL);
 283         sigaction(SIGTSTP, &sa, NULL);
 284
 285         signal_del(&tp->ev_sigint);
 286         signal_del(&tp->ev_sighup);
 287         signal_del(&tp->ev_sigchld);
 288         signal_del(&tp->ev_sigcont);
 289         signal_del(&tp->ev_sigterm);
 290         signal_del(&tp->ev_sigusr1);
 291         signal_del(&tp->ev_sigusr2);
 292         signal_del(&tp->ev_sigwinch);
 293
 294         if (defaults) {
 295                 sigaction(SIGINT, &sa, NULL);
 296                 sigaction(SIGQUIT, &sa, NULL);
 297                 sigaction(SIGHUP, &sa, NULL);
 298                 sigaction(SIGCHLD, &sa, NULL);
 299                 sigaction(SIGCONT, &sa, NULL);
 300                 sigaction(SIGTERM, &sa, NULL);
 301                 sigaction(SIGUSR1, &sa, NULL);
 302                 sigaction(SIGUSR2, &sa, NULL);
 303                 sigaction(SIGWINCH, &sa, NULL);
 304         }
 305 }
 306
 307 struct tmuxpeer *
 308 proc_add_peer(struct tmuxproc *tp, int fd,
 309     void (*dispatchcb)(struct imsg *, void *), void *arg)
 310 {
 311         struct tmuxpeer *peer;
 312         gid_t            gid;
 313
 314         peer = xcalloc(1, sizeof *peer);
 315         peer->parent = tp;
 316
 317         peer->dispatchcb = dispatchcb;
 318         peer->arg = arg;
 319
 320         imsg_init(&peer->ibuf, fd);
 321         event_set(&peer->event, fd, EV_READ, proc_event_cb, peer);
 322
 323         if (getpeereid(fd, &peer->uid, &gid) != 0)
 324                 peer->uid = (uid_t)-1;
 325
 326         log_debug("add peer %p: %d (%p)", peer, fd, arg);
 327         TAILQ_INSERT_TAIL(&tp->peers, peer, entry);
 328
 329         proc_update_event(peer);
 330         return (peer);
 331 }
 332
 333 void
 334 proc_remove_peer(struct tmuxpeer *peer)
 335 {
 336         TAILQ_REMOVE(&peer->parent->peers, peer, entry);
 337         log_debug("remove peer %p", peer);
 338
 339         event_del(&peer->event);
 340         imsg_clear(&peer->ibuf);
 341
 342         close(peer->ibuf.fd);
 343         free(peer);
 344 }
 345
 346 void
 347 proc_kill_peer(struct tmuxpeer *peer)
 348 {
 349         peer->flags |= PEER_BAD;
 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 }