client.c

   1 /* $OpenBSD$ */
   2
   3 /*
   4  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
   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/stat.h>
  22 #include <sys/un.h>
  23 #include <sys/wait.h>
  24
  25 #include <errno.h>
  26 #include <event.h>
  27 #include <fcntl.h>
  28 #include <pwd.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <syslog.h>
  32 #include <unistd.h>
  33
  34 #include "tmux.h"
  35
  36 struct imsgbuf  client_ibuf;
  37 struct event    client_event;
  38 const char     *client_exitmsg;
  39 int             client_exitval;
  40
  41 void            client_send_identify(int);
  42 void            client_send_environ(void);
  43 void            client_write_server(enum msgtype, void *, size_t);
  44 void            client_update_event(void);
  45 void            client_signal(int, short, void *);
  46 void            client_callback(int, short, void *);
  47 int             client_dispatch(void);
  48
  49 struct imsgbuf *
  50 client_init(char *path, int cmdflags, int flags)
  51 {
  52         struct sockaddr_un      sa;
  53         size_t                  size;
  54         int                     fd, mode;
  55         char                    rpathbuf[MAXPATHLEN];
  56
  57         if (realpath(path, rpathbuf) == NULL)
  58                 strlcpy(rpathbuf, path, sizeof rpathbuf);
  59         setproctitle("client (%s)", rpathbuf);
  60
  61         memset(&sa, 0, sizeof sa);
  62         sa.sun_family = AF_UNIX;
  63         size = strlcpy(sa.sun_path, path, sizeof sa.sun_path);
  64         if (size >= sizeof sa.sun_path) {
  65                 errno = ENAMETOOLONG;
  66                 goto not_found;
  67         }
  68
  69         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
  70                 fatal("socket failed");
  71
  72         if (connect(fd, (struct sockaddr *) &sa, SUN_LEN(&sa)) == -1) {
  73                 if (!(cmdflags & CMD_STARTSERVER))
  74                         goto not_found;
  75                 switch (errno) {
  76                 case ECONNREFUSED:
  77                         if (unlink(path) != 0)
  78                                 goto not_found;
  79                         /* FALLTHROUGH */
  80                 case ENOENT:
  81                         if ((fd = server_start(path)) == -1)
  82                                 goto start_failed;
  83                         goto server_started;
  84                 }
  85                 goto not_found;
  86         }
  87
  88 server_started:
  89         if ((mode = fcntl(fd, F_GETFL)) == -1)
  90                 fatal("fcntl failed");
  91         if (fcntl(fd, F_SETFL, mode|O_NONBLOCK) == -1)
  92                 fatal("fcntl failed");
  93         if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
  94                 fatal("fcntl failed");
  95         imsg_init(&client_ibuf, fd);
  96         event_set(&client_event, fd, EV_READ, client_callback, NULL);
  97
  98         if (cmdflags & CMD_SENDENVIRON)
  99                 client_send_environ();
 100         client_send_identify(flags);
 101
 102         return (&client_ibuf);
 103
 104 start_failed:
 105         log_warnx("server failed to start");
 106         return (NULL);
 107
 108 not_found:
 109         log_warn("server not found");
 110         return (NULL);
 111 }
 112
 113 void
 114 client_send_identify(int flags)
 115 {
 116         struct msg_identify_data        data;
 117         char                           *term;
 118         int                             fd;
 119
 120         data.flags = flags;
 121
 122         if (getcwd(data.cwd, sizeof data.cwd) == NULL)
 123                 *data.cwd = '\0';
 124
 125         term = getenv("TERM");
 126         if (term == NULL ||
 127             strlcpy(data.term, term, sizeof data.term) >= sizeof data.term)
 128                 *data.term = '\0';
 129
 130         if ((fd = dup(STDIN_FILENO)) == -1)
 131                 fatal("dup failed");
 132         imsg_compose(&client_ibuf,
 133             MSG_IDENTIFY, PROTOCOL_VERSION, -1, fd, &data, sizeof data);
 134
 135         if ((fd = dup(STDOUT_FILENO)) == -1)
 136                 fatal("dup failed");
 137         imsg_compose(&client_ibuf, MSG_STDOUT, PROTOCOL_VERSION, -1, fd, NULL, 0);
 138
 139         if ((fd = dup(STDERR_FILENO)) == -1)
 140                 fatal("dup failed");
 141         imsg_compose(&client_ibuf, MSG_STDERR, PROTOCOL_VERSION, -1, fd, NULL, 0);
 142 }
 143
 144 void
 145 client_send_environ(void)
 146 {
 147         struct msg_environ_data data;
 148         char                  **var;
 149
 150         for (var = environ; *var != NULL; var++) {
 151                 if (strlcpy(data.var, *var, sizeof data.var) >= sizeof data.var)
 152                         continue;
 153                 client_write_server(MSG_ENVIRON, &data, sizeof data);
 154         }
 155 }
 156
 157 void
 158 client_write_server(enum msgtype type, void *buf, size_t len)
 159 {
 160         imsg_compose(&client_ibuf, type, PROTOCOL_VERSION, -1, -1, buf, len);
 161 }
 162
 163 void
 164 client_update_event(void)
 165 {
 166         short   events;
 167
 168         event_del(&client_event);
 169         events = EV_READ;
 170         if (client_ibuf.w.queued > 0)
 171                 events |= EV_WRITE;
 172         event_set(&client_event, client_ibuf.fd, events, client_callback, NULL);
 173         event_add(&client_event, NULL);
 174 }
 175
 176 __dead void
 177 client_main(void)
 178 {
 179         logfile("client");
 180
 181         /* Note: event_init() has already been called. */
 182
 183         /* Set up signals. */
 184         set_signals(client_signal);
 185
 186         /*
 187          * Send a resize message immediately in case the terminal size has
 188          * changed between the identify message to the server and the MSG_READY
 189          * telling us to move into the client code.
 190          */
 191          client_write_server(MSG_RESIZE, NULL, 0);
 192
 193         /*
 194          * imsg_read in the first client poll loop (before the terminal has
 195          * been initialised) may have read messages into the buffer after the
 196          * MSG_READY switched to here. Process anything outstanding now to
 197          * avoid hanging waiting for messages that have already arrived.
 198          */
 199         if (client_dispatch() != 0)
 200                 goto out;
 201
 202         /* Set the event and dispatch. */
 203         client_update_event();
 204         event_dispatch();
 205
 206 out:
 207         /* Print the exit message, if any, and exit. */
 208         if (client_exitmsg != NULL && !login_shell)
 209                 printf("[%s]\n", client_exitmsg);
 210         exit(client_exitval);
 211 }
 212
 213 /* ARGSUSED */
 214 void
 215 client_signal(int sig, unused short events, unused void *data)
 216 {
 217         struct sigaction        sigact;
 218
 219         switch (sig) {
 220         case SIGHUP:
 221                 client_exitmsg = "lost tty";
 222                 client_exitval = 1;
 223                 client_write_server(MSG_EXITING, NULL, 0);
 224                 break;
 225         case SIGTERM:
 226                 client_exitmsg = "terminated";
 227                 client_exitval = 1;
 228                 client_write_server(MSG_EXITING, NULL, 0);
 229                 break;
 230         case SIGWINCH:
 231                 client_write_server(MSG_RESIZE, NULL, 0);
 232                 break;
 233         case SIGCONT:
 234                 memset(&sigact, 0, sizeof sigact);
 235                 sigemptyset(&sigact.sa_mask);
 236                 sigact.sa_flags = SA_RESTART;
 237                 sigact.sa_handler = SIG_IGN;
 238                 if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 239                         fatal("sigaction failed");
 240                 client_write_server(MSG_WAKEUP, NULL, 0);
 241                 break;
 242         }
 243
 244         client_update_event();
 245 }
 246
 247 /* ARGSUSED */
 248 void
 249 client_callback(unused int fd, short events, unused void *data)
 250 {
 251         ssize_t n;
 252
 253         if (events & EV_READ) {
 254                 if ((n = imsg_read(&client_ibuf)) == -1 || n == 0)
 255                         goto lost_server;
 256                 if (client_dispatch() != 0) {
 257                         event_loopexit(NULL);
 258                         return;
 259                 }
 260         }
 261
 262         if (events & EV_WRITE) {
 263                 if (msgbuf_write(&client_ibuf.w) < 0)
 264                         goto lost_server;
 265         }
 266
 267         client_update_event();
 268         return;
 269
 270 lost_server:
 271         client_exitmsg = "lost server";
 272         client_exitval = 1;
 273         event_loopexit(NULL);
 274 }
 275
 276 int
 277 client_dispatch(void)
 278 {
 279         struct imsg             imsg;
 280         struct msg_lock_data    lockdata;
 281         struct sigaction        sigact;
 282         ssize_t                 n, datalen;
 283
 284         for (;;) {
 285                 if ((n = imsg_get(&client_ibuf, &imsg)) == -1)
 286                         fatalx("imsg_get failed");
 287                 if (n == 0)
 288                         return (0);
 289                 datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
 290
 291                 log_debug("client got %d", imsg.hdr.type);
 292                 switch (imsg.hdr.type) {
 293                 case MSG_DETACH:
 294                         if (datalen != 0)
 295                                 fatalx("bad MSG_DETACH size");
 296
 297                         client_write_server(MSG_EXITING, NULL, 0);
 298                         client_exitmsg = "detached";
 299                         break;
 300                 case MSG_EXIT:
 301                         if (datalen != 0 &&
 302                             datalen != sizeof (struct msg_exit_data))
 303                                 fatalx("bad MSG_EXIT size");
 304
 305                         client_write_server(MSG_EXITING, NULL, 0);
 306                         client_exitmsg = "exited";
 307                         break;
 308                 case MSG_EXITED:
 309                         if (datalen != 0)
 310                                 fatalx("bad MSG_EXITED size");
 311
 312                         imsg_free(&imsg);
 313                         return (-1);
 314                 case MSG_SHUTDOWN:
 315                         if (datalen != 0)
 316                                 fatalx("bad MSG_SHUTDOWN size");
 317
 318                         client_write_server(MSG_EXITING, NULL, 0);
 319                         client_exitmsg = "server exited";
 320                         client_exitval = 1;
 321                         break;
 322                 case MSG_SUSPEND:
 323                         if (datalen != 0)
 324                                 fatalx("bad MSG_SUSPEND size");
 325
 326                         memset(&sigact, 0, sizeof sigact);
 327                         sigemptyset(&sigact.sa_mask);
 328                         sigact.sa_flags = SA_RESTART;
 329                         sigact.sa_handler = SIG_DFL;
 330                         if (sigaction(SIGTSTP, &sigact, NULL) != 0)
 331                                 fatal("sigaction failed");
 332                         kill(getpid(), SIGTSTP);
 333                         break;
 334                 case MSG_LOCK:
 335                         if (datalen != sizeof lockdata)
 336                                 fatalx("bad MSG_LOCK size");
 337                         memcpy(&lockdata, imsg.data, sizeof lockdata);
 338
 339                         lockdata.cmd[(sizeof lockdata.cmd) - 1] = '\0';
 340                         system(lockdata.cmd);
 341                         client_write_server(MSG_UNLOCK, NULL, 0);
 342                         break;
 343                 default:
 344                         fatalx("unexpected message");
 345                 }
 346
 347                 imsg_free(&imsg);
 348         }
 349 }