lib-src/emacsclient.c

   1 /* Client process that communicates with GNU Emacs acting as server.
   2    Copyright (C) 1986, 1987, 1994, 1999, 2000, 2001, 2003
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22
  23 #define NO_SHORTNAMES
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include <config.h>
  27 #endif
  28
  29 #undef signal
  30
  31 #include <ctype.h>
  32 #include <stdio.h>
  33 #include <getopt.h>
  34 #ifdef HAVE_UNISTD_H
  35 #include <unistd.h>
  36 #endif
  37
  38 #ifdef VMS
  39 # include "vms-pwd.h"
  40 #else
  41 # include <pwd.h>
  42 #endif /* not VMS */
  43
  44
  45 /****************************************/
  46
  47 #include <errno.h>
  48 #include <signal.h>
  49
  50 #ifndef INCLUDED_FCNTL
  51 #define INCLUDED_FCNTL
  52 #include <fcntl.h>
  53 #endif
  54
  55 #ifdef HAVE_TERMIOS
  56 #ifndef NO_TERMIO
  57 #include <termio.h>
  58 #endif
  59 #include <termios.h>
  60 #endif /* not HAVE_TERMIOS */
  61
  62 #ifdef __GNU_LIBRARY__
  63 #include <sys/ioctl.h>
  64 #include <termios.h>
  65 #endif
  66
  67 #if (defined (POSIX) || defined (NEED_UNISTD_H)) && defined (HAVE_UNISTD_H)
  68 #include <unistd.h>
  69 #endif
  70
  71
  72 \f
  73 /* Try to establish the correct character to disable terminal functions
  74    in a system-independent manner.  Note that USG (at least) define
  75    _POSIX_VDISABLE as 0!  */
  76
  77 #ifdef _POSIX_VDISABLE
  78 #define CDISABLE _POSIX_VDISABLE
  79 #else /* not _POSIX_VDISABLE */
  80 #ifdef CDEL
  81 #undef CDISABLE
  82 #define CDISABLE CDEL
  83 #else /* not CDEL */
  84 #define CDISABLE 255
  85 #endif /* not CDEL */
  86 #endif /* not _POSIX_VDISABLE */
  87 \f
  88
  89
  90 /****************************************/
  91
  92 char *getenv (), *getwd ();
  93 char *getcwd ();
  94
  95 /* This is defined with -D from the compilation command,
  96    which extracts it from ../lisp/version.el.  */
  97
  98 #ifndef VERSION
  99 #define VERSION "unspecified"
 100 #endif
 101 \f
 102 /* Name used to invoke this program.  */
 103 char *progname;
 104
 105 /* The first argument to main. */
 106 int main_argc;
 107
 108 /* The second argument to main. */
 109 char **main_argv;
 110
 111 /* Nonzero means don't wait for a response from Emacs.  --no-wait.  */
 112 int nowait = 0;
 113
 114 /* Nonzero means args are expressions to be evaluated.  --eval.  */
 115 int eval = 0;
 116
 117 /* The display on which Emacs should work.  --display.  */
 118 char *display = NULL;
 119
 120 /* Nonzero means open a new Emacs frame on the current terminal. */
 121 int frame = 0;
 122
 123 /* If non-NULL, the name of an editor to fallback to if the server
 124    is not running.  --alternate-editor.   */
 125 const char * alternate_editor = NULL;
 126
 127 /* If non-NULL, the filename of the UNIX socket.  */
 128 char *socket_name = NULL;
 129
 130 void print_help_and_exit ();
 131
 132 struct option longopts[] =
 133 {
 134   { "no-wait",  no_argument,       NULL, 'n' },
 135   { "eval",     no_argument,       NULL, 'e' },
 136   { "help",     no_argument,       NULL, 'H' },
 137   { "version",  no_argument,       NULL, 'V' },
 138   { "frame",    no_argument,       NULL, 'f' },
 139   { "alternate-editor", required_argument, NULL, 'a' },
 140   { "socket-name",      required_argument, NULL, 's' },
 141   { "display",  required_argument, NULL, 'd' },
 142   { 0, 0, 0, 0 }
 143 };
 144
 145 /* Decode the options from argv and argc.
 146    The global variable `optind' will say how many arguments we used up.  */
 147
 148 void
 149 decode_options (argc, argv)
 150      int argc;
 151      char **argv;
 152 {
 153   while (1)
 154     {
 155       int opt = getopt_long (argc, argv,
 156                              "VHnea:s:d:t", longopts, 0);
 157
 158       if (opt == EOF)
 159         break;
 160
 161       alternate_editor = getenv ("ALTERNATE_EDITOR");
 162
 163       switch (opt)
 164         {
 165         case 0:
 166           /* If getopt returns 0, then it has already processed a
 167              long-named option.  We should do nothing.  */
 168           break;
 169
 170         case 'a':
 171           alternate_editor = optarg;
 172           break;
 173
 174         case 's':
 175           socket_name = optarg;
 176           break;
 177
 178         case 'd':
 179           display = optarg;
 180           break;
 181
 182         case 'n':
 183           nowait = 1;
 184           break;
 185
 186         case 'e':
 187           eval = 1;
 188           break;
 189
 190         case 'V':
 191           printf ("emacsclient %s\n", VERSION);
 192           exit (0);
 193           break;
 194
 195         case 't':
 196           frame = 1;
 197           break;
 198
 199         case 'H':
 200           print_help_and_exit ();
 201           break;
 202
 203         default:
 204           fprintf (stderr, "Try `%s --help' for more information\n", progname);
 205           exit (1);
 206           break;
 207         }
 208     }
 209
 210   if (frame) {
 211     nowait = 0;
 212     display = 0;
 213   }
 214
 215 }
 216
 217 void
 218 print_help_and_exit ()
 219 {
 220   printf (
 221           "Usage: %s [OPTIONS] FILE...\n\
 222 Tell the Emacs server to visit the specified files.\n\
 223 Every FILE can be either just a FILENAME or [+LINE[:COLUMN]] FILENAME.\n\
 224 \n\
 225 The following OPTIONS are accepted:\n\
 226 -V, --version           Just print a version info and return\n\
 227 -H, --help              Print this usage information message\n\
 228 -t, --tty               Open a new Emacs frame on the current terminal\n\
 229 -n, --no-wait           Don't wait for the server to return\n\
 230 -e, --eval              Evaluate the FILE arguments as ELisp expressions\n\
 231 -d, --display=DISPLAY   Visit the file in the given display\n\
 232 -s, --socket-name=FILENAME\n\
 233                         Set the filename of the UNIX socket for communication\n\
 234 -a, --alternate-editor=EDITOR\n\
 235                         Editor to fallback to if the server is not running\n\
 236 \n\
 237 Report bugs to bug-gnu-emacs@gnu.org.\n", progname);
 238   exit (0);
 239 }
 240
 241 /* In NAME, insert a & before each &, each space, each newline, and
 242    any initial -.  Change spaces to underscores, too, so that the
 243    return value never contains a space.  */
 244
 245 void
 246 quote_file_name (name, stream)
 247      char *name;
 248      FILE *stream;
 249 {
 250   char *copy = (char *) malloc (strlen (name) * 2 + 1);
 251   char *p, *q;
 252
 253   p = name;
 254   q = copy;
 255   while (*p)
 256     {
 257       if (*p == ' ')
 258         {
 259           *q++ = '&';
 260           *q++ = '_';
 261           p++;
 262         }
 263       else if (*p == '\n')
 264         {
 265           *q++ = '&';
 266           *q++ = 'n';
 267           p++;
 268         }
 269       else
 270         {
 271           if (*p == '&' || (*p == '-' && p == name))
 272             *q++ = '&';
 273           *q++ = *p++;
 274         }
 275     }
 276   *q++ = 0;
 277
 278   fprintf (stream, copy);
 279
 280   free (copy);
 281 }
 282
 283 /* Like malloc but get fatal error if memory is exhausted.  */
 284
 285 long *
 286 xmalloc (size)
 287      unsigned int size;
 288 {
 289   long *result = (long *) malloc (size);
 290   if (result == NULL)
 291   {
 292     perror ("malloc");
 293     exit (1);
 294   }
 295   return result;
 296 }
 297 \f
 298 /*
 299   Try to run a different command, or --if no alternate editor is
 300   defined-- exit with an errorcode.
 301 */
 302 void
 303 fail (void)
 304 {
 305   if (alternate_editor)
 306     {
 307       int i = optind - 1;
 308       execvp (alternate_editor, main_argv + i);
 309       return;
 310     }
 311   else
 312     {
 313       exit (1);
 314     }
 315 }
 316
 317 \f
 318 #ifdef HAVE_TERMIOS
 319
 320 /* Adapted from emacs_get_tty() in sysdep.c. */
 321 int
 322 ec_get_tty (int fd, struct termios *settings)
 323 {
 324   bzero (settings, sizeof (struct termios));
 325   if (tcgetattr (fd, settings) < 0)
 326     return -1;
 327   return 0;
 328 }
 329
 330 /* Adapted from emacs_set_tty() in sysdep.c. */
 331 int
 332 ec_set_tty (int fd, struct termios *settings, int flushp)
 333 {
 334   /* Set the primary parameters - baud rate, character size, etcetera.  */
 335
 336   int i;
 337   /* We have those nifty POSIX tcmumbleattr functions.
 338      William J. Smith <wjs@wiis.wang.com> writes:
 339      "POSIX 1003.1 defines tcsetattr to return success if it was
 340      able to perform any of the requested actions, even if some
 341      of the requested actions could not be performed.
 342      We must read settings back to ensure tty setup properly.
 343      AIX requires this to keep tty from hanging occasionally."  */
 344   /* This make sure that we don't loop indefinitely in here.  */
 345   for (i = 0 ; i < 10 ; i++)
 346     if (tcsetattr (fd, flushp ? TCSAFLUSH : TCSADRAIN, settings) < 0)
 347       {
 348         if (errno == EINTR)
 349           continue;
 350         else
 351           return -1;
 352       }
 353     else
 354       {
 355         struct termios new;
 356
 357         bzero (&new, sizeof (new));
 358         /* Get the current settings, and see if they're what we asked for.  */
 359         tcgetattr (fd, &new);
 360         /* We cannot use memcmp on the whole structure here because under
 361          * aix386 the termios structure has some reserved field that may
 362          * not be filled in.
 363          */
 364         if (   new.c_iflag == settings->c_iflag
 365             && new.c_oflag == settings->c_oflag
 366             && new.c_cflag == settings->c_cflag
 367             && new.c_lflag == settings->c_lflag
 368             && memcmp (new.c_cc, settings->c_cc, NCCS) == 0)
 369           break;
 370         else
 371           continue;
 372       }
 373   return 0;
 374 }
 375
 376 int master;
 377 char *pty_name;
 378
 379 struct termios old_tty;
 380 struct termios tty;
 381 int old_tty_valid;
 382
 383 int tty_erase_char;
 384 int quit_char = 'g' & 037;
 385 int flow_control = 0;
 386 int meta_key = 0;
 387 char _sobuf[BUFSIZ];
 388 int emacs_pid;
 389
 390 /* Adapted from init_sys_modes() in sysdep.c. */
 391 int
 392 init_tty ()
 393 {
 394   if (! isatty (0))
 395     {
 396       fprintf (stderr, "%s: Input is not a terminal", "init_tty");
 397       return 0;
 398     }
 399
 400   ec_get_tty (0, &old_tty);
 401   old_tty_valid = 1;
 402   tty = old_tty;
 403
 404   tty_erase_char = old_tty.c_cc[VERASE];
 405
 406   tty.c_iflag |= (IGNBRK);      /* Ignore break condition */
 407   tty.c_iflag &= ~ICRNL;        /* Disable map of CR to NL on input */
 408 #ifdef INLCR
 409   tty.c_iflag &= ~INLCR;        /* Disable map of NL to CR on input */
 410 #endif
 411 #ifdef ISTRIP
 412   tty.c_iflag &= ~ISTRIP;       /* don't strip 8th bit on input */
 413 #endif
 414   tty.c_lflag &= ~ECHO;         /* Disable echo */
 415   tty.c_lflag &= ~ICANON;       /* Disable erase/kill processing */
 416 #ifdef IEXTEN
 417   tty.c_lflag &= ~IEXTEN;       /* Disable other editing characters.  */
 418 #endif
 419   tty.c_lflag |= ISIG;          /* Enable signals */
 420   if (flow_control)
 421     {
 422       tty.c_iflag |= IXON;      /* Enable start/stop output control */
 423 #ifdef IXANY
 424       tty.c_iflag &= ~IXANY;
 425 #endif /* IXANY */
 426     }
 427   else
 428     tty.c_iflag &= ~IXON;       /* Disable start/stop output control */
 429   tty.c_oflag &= ~ONLCR;        /* Disable map of NL to CR-NL
 430                                    on output */
 431   tty.c_oflag &= ~TAB3;         /* Disable tab expansion */
 432 #ifdef CS8
 433   if (meta_key)
 434     {
 435       tty.c_cflag |= CS8;       /* allow 8th bit on input */
 436       tty.c_cflag &= ~PARENB;   /* Don't check parity */
 437     }
 438 #endif
 439   tty.c_cc[VINTR] = quit_char;  /* C-g (usually) gives SIGINT */
 440   /* Set up C-g for both SIGQUIT and SIGINT.
 441      We don't know which we will get, but we handle both alike
 442      so which one it really gives us does not matter.  */
 443   tty.c_cc[VQUIT] = quit_char;
 444   tty.c_cc[VMIN] = 1;      /* Input should wait for at least 1 char */
 445   tty.c_cc[VTIME] = 0;          /* no matter how long that takes.  */
 446 #ifdef VSWTCH
 447   tty.c_cc[VSWTCH] = CDISABLE;  /* Turn off shell layering use of C-z */
 448 #endif
 449
 450 #ifdef VSUSP
 451   tty.c_cc[VSUSP] = CDISABLE;   /* Turn off mips handling of C-z.  */
 452 #endif /* VSUSP */
 453 #ifdef V_DSUSP
 454   tty.c_cc[V_DSUSP] = CDISABLE; /* Turn off mips handling of C-y.  */
 455 #endif /* V_DSUSP */
 456 #ifdef VDSUSP /* Some systems have VDSUSP, some have V_DSUSP.  */
 457   tty.c_cc[VDSUSP] = CDISABLE;
 458 #endif /* VDSUSP */
 459 #ifdef VLNEXT
 460   tty.c_cc[VLNEXT] = CDISABLE;
 461 #endif /* VLNEXT */
 462 #ifdef VREPRINT
 463   tty.c_cc[VREPRINT] = CDISABLE;
 464 #endif /* VREPRINT */
 465 #ifdef VWERASE
 466   tty.c_cc[VWERASE] = CDISABLE;
 467 #endif /* VWERASE */
 468 #ifdef VDISCARD
 469   tty.c_cc[VDISCARD] = CDISABLE;
 470 #endif /* VDISCARD */
 471
 472   if (flow_control)
 473     {
 474 #ifdef VSTART
 475       tty.c_cc[VSTART] = '\021';
 476 #endif /* VSTART */
 477 #ifdef VSTOP
 478       tty.c_cc[VSTOP] = '\023';
 479 #endif /* VSTOP */
 480     }
 481   else
 482     {
 483 #ifdef VSTART
 484       tty.c_cc[VSTART] = CDISABLE;
 485 #endif /* VSTART */
 486 #ifdef VSTOP
 487       tty.c_cc[VSTOP] = CDISABLE;
 488 #endif /* VSTOP */
 489     }
 490
 491 #ifdef SET_LINE_DISCIPLINE
 492   /* Need to explicitly request TERMIODISC line discipline or
 493      Ultrix's termios does not work correctly.  */
 494   tty.c_line = SET_LINE_DISCIPLINE;
 495 #endif
 496
 497 #ifdef AIX
 498 #ifndef IBMR2AIX
 499   /* AIX enhanced edit loses NULs, so disable it.  */
 500   tty.c_line = 0;
 501   tty.c_iflag &= ~ASCEDIT;
 502 #else
 503   tty.c_cc[VSTRT] = 255;
 504   tty.c_cc[VSTOP] = 255;
 505   tty.c_cc[VSUSP] = 255;
 506   tty.c_cc[VDSUSP] = 255;
 507 #endif /* IBMR2AIX */
 508   if (flow_control)
 509     {
 510 #ifdef VSTART
 511       tty.c_cc[VSTART] = '\021';
 512 #endif /* VSTART */
 513 #ifdef VSTOP
 514       tty.c_cc[VSTOP] = '\023';
 515 #endif /* VSTOP */
 516     }
 517   /* Also, PTY overloads NUL and BREAK.
 518      don't ignore break, but don't signal either, so it looks like NUL.
 519      This really serves a purpose only if running in an XTERM window
 520      or via TELNET or the like, but does no harm elsewhere.  */
 521   tty.c_iflag &= ~IGNBRK;
 522   tty.c_iflag &= ~BRKINT;
 523 #endif /* AIX */
 524
 525   ec_set_tty (0, &tty, 0);
 526
 527       /* This code added to insure that, if flow-control is not to be used,
 528          we have an unlocked terminal at the start. */
 529
 530 #ifdef TCXONC
 531   if (!flow_control) ioctl (0, TCXONC, 1);
 532 #endif
 533 #ifndef APOLLO
 534 #ifdef TIOCSTART
 535   if (!flow_control) ioctl (0, TIOCSTART, 0);
 536 #endif
 537 #endif
 538
 539 #if defined (HAVE_TERMIOS) || defined (HPUX9)
 540 #ifdef TCOON
 541   if (!flow_control) tcflow (0, TCOON);
 542 #endif
 543 #endif
 544
 545 #ifdef _IOFBF
 546   /* This symbol is defined on recent USG systems.
 547      Someone says without this call USG won't really buffer the file
 548      even with a call to setbuf. */
 549   setvbuf (stdout, (char *) _sobuf, _IOFBF, sizeof _sobuf);
 550 #else
 551   setbuf (stdout, (char *) _sobuf);
 552 #endif
 553
 554   return 1;
 555 }
 556
 557 void
 558 window_change ()
 559 {
 560   int width = 0, height = 0;
 561
 562 #ifdef TIOCGWINSZ
 563   {
 564     /* BSD-style.  */
 565     struct winsize size;
 566
 567     if (ioctl (0, TIOCGWINSZ, &size) == -1)
 568       width = height = 0;
 569     else
 570       {
 571         width = size.ws_col;
 572         height = size.ws_row;
 573       }
 574   }
 575 #else
 576 #ifdef TIOCGSIZE
 577   {
 578     /* SunOS - style.  */
 579     struct ttysize size;
 580
 581     if (ioctl (0, TIOCGSIZE, &size) == -1)
 582       width = height = 0;
 583     else
 584       {
 585         width = size.ts_cols;
 586         height = size.ts_lines;
 587       }
 588   }
 589 #endif /* not SunOS-style */
 590 #endif /* not BSD-style */
 591
 592 #ifdef TIOCSWINSZ
 593   {
 594     /* BSD-style.  */
 595     struct winsize size;
 596     size.ws_row = height;
 597     size.ws_col = width;
 598
 599     ioctl (master, TIOCSWINSZ, &size);
 600   }
 601 #else
 602 #ifdef TIOCSSIZE
 603   {
 604     /* SunOS - style.  */
 605     struct ttysize size;
 606     size.ts_lines = height;
 607     size.ts_cols = width;
 608
 609     ioctl (master, TIOCGSIZE, &size);
 610   }
 611 #endif /* not SunOS-style */
 612 #endif /* not BSD-style */
 613
 614   if (emacs_pid && width && height)
 615     kill (emacs_pid, SIGWINCH);
 616 }
 617
 618 int in_conversation = 0;
 619 int quit_conversation = 0;
 620
 621 SIGTYPE
 622 hang_up_signal (int signalnum)
 623 {
 624   int old_errno = errno;
 625
 626   if (! in_conversation)
 627     return;
 628
 629   quit_conversation = 1;
 630
 631   errno = old_errno;
 632 }
 633
 634 SIGTYPE
 635 window_change_signal (int signalnum)
 636 {
 637   int old_errno = errno;
 638
 639   if (! in_conversation)
 640     goto end;
 641
 642   window_change();
 643
 644  end:
 645   signal (SIGWINCH, window_change_signal);
 646   errno = old_errno;
 647 }
 648
 649 SIGTYPE
 650 interrupt_signal (int signalnum)
 651 {
 652   int old_errno = errno;
 653
 654   /* Forward it to Emacs. */
 655   if (emacs_pid)
 656     kill (emacs_pid, SIGINT);
 657
 658   errno = old_errno;
 659 }
 660
 661 int
 662 init_signals ()
 663 {
 664   /* Set up signal handlers. */
 665   signal (SIGWINCH, window_change_signal);
 666   signal (SIGHUP, hang_up_signal);
 667   signal (SIGINT, interrupt_signal);
 668   return 1;
 669 }
 670
 671
 672
 673 /* Adapted from reset_sys_modes in sysdep.c. */
 674 int
 675 reset_tty ()
 676 {
 677   fflush (stdout);
 678 #ifdef BSD_SYSTEM
 679 #ifndef BSD4_1
 680   /* Avoid possible loss of output when changing terminal modes.  */
 681   fsync (fileno (stdout));
 682 #endif
 683 #endif
 684
 685 #ifdef F_SETFL
 686 #ifdef O_NDELAY
 687   fcntl (0, F_SETFL, fcntl (0, F_GETFL, 0) & ~O_NDELAY);
 688 #endif
 689 #endif /* F_SETFL */
 690
 691   if (old_tty_valid)
 692     while (ec_set_tty (0, &old_tty, 0) < 0 && errno == EINTR)
 693       ;
 694
 695   return 1;
 696 }
 697
 698
 699 int
 700 init_pty ()
 701 {
 702   master = getpt ();
 703   if (master < 0)
 704     return 0;
 705
 706   if (grantpt (master) < 0 || unlockpt (master) < 0)
 707     goto close_master;
 708   pty_name = strdup (ptsname (master));
 709   if (! pty_name)
 710     goto close_master;
 711
 712   /* Propagate window size. */
 713   window_change ();
 714
 715   return 1;
 716
 717  close_master:
 718   close (master);
 719   return 0;
 720 }
 721
 722 int
 723 copy_from_to (int in, int out, int sigio)
 724 {
 725   static char buf[BUFSIZ];
 726   int nread = read (in, &buf, BUFSIZ);
 727   if (nread == 0)
 728     return 1;                   /* EOF */
 729   else if (nread < 0 && errno != EAGAIN)
 730     return 0;
 731   else if (nread > 0)
 732     {
 733       int r = 0;
 734       int written = 0;
 735
 736       do {
 737         r = write (out, &buf, nread);
 738       } while ((r < 0 && errno == EINTR)
 739                || (r > 0 && (written += r) && written != nread));
 740
 741       if (r < 0)
 742         return 0;
 743
 744       if (sigio && emacs_pid)
 745         kill (emacs_pid, SIGIO);
 746     }
 747   return 1;
 748 }
 749
 750 int
 751 pty_conversation (FILE *in)
 752 {
 753   char *str;
 754   char string[BUFSIZ];
 755   fd_set set, rset;
 756   int res;
 757
 758   FD_ZERO (&set);
 759   FD_SET (master, &set);
 760   FD_SET (1, &set);
 761   FD_SET (fileno (in), &set);
 762
 763   in_conversation = 1;
 764
 765   while (! quit_conversation) {
 766     rset = set;
 767     res = select (FD_SETSIZE, &rset, NULL, NULL, NULL);
 768     if (res < 0 && errno != EINTR)
 769       {
 770           reset_tty ();
 771           fprintf (stderr, "%s: ", progname);
 772           perror ("select");
 773           return 0;             /* Error */
 774       }
 775     else if (res > 0)
 776       {
 777         if (FD_ISSET (master, &rset))
 778           {
 779             /* Copy Emacs output to stdout. */
 780             if (! copy_from_to (master, 0, 0))
 781               {
 782                 FD_CLR (master, &set);
 783               }
 784           }
 785         if (FD_ISSET (1, &rset))
 786           {
 787             /* Forward user input to Emacs. */
 788             if (! copy_from_to (1, master, 1))
 789               {
 790                 FD_CLR (master, &set);
 791               }
 792           }
 793         if (FD_ISSET (fileno (in), &rset))
 794           {
 795             do {
 796               res = read (fileno (in), string, BUFSIZ-1);
 797             } while (res < 0 && errno == EINTR);
 798             if (res < 0)
 799               {
 800                 reset_tty ();
 801                 fprintf (stderr, "%s: ", progname);
 802                 perror ("read");
 803                 return 0;
 804               }
 805             if (!res)
 806               {
 807                 return 1;
 808               }
 809
 810             string[res] = 0;
 811             if (string[res-1] == '\n')
 812               string[res-1] = 0;
 813
 814             if (! emacs_pid)
 815               {
 816                 /* Get the pid of the Emacs process.
 817                    XXX Is there some nifty libc/kernel feature for doing this?
 818                 */
 819                 if (! string[0])
 820                   {
 821                     reset_tty ();
 822                     fprintf (stderr, "%s: could not get Emacs process id\n"
 823                              "Maybe this Emacs does not support multiple terminals.\n", progname);
 824                     return 0;
 825                   }
 826                 emacs_pid = strtol (string, NULL, 10);
 827               }
 828
 829             if (! emacs_pid)    /* emacs_pid should be set above */
 830               {
 831                 reset_tty ();
 832                 fprintf (stderr, "%s: %s\n", progname, string);
 833                 return 0;
 834               }
 835           }
 836       }
 837   }
 838   return 1;
 839 }
 840
 841 #endif /* HAVE_TERMIOS */
 842
 843 \f
 844 #if !defined (HAVE_SOCKETS) || defined (NO_SOCKETS_IN_FILE_SYSTEM)
 845
 846 int
 847 main (argc, argv)
 848      int argc;
 849      char **argv;
 850 {
 851   fprintf (stderr, "%s: Sorry, the Emacs server is supported only\n",
 852            argv[0]);
 853   fprintf (stderr, "on systems with Berkeley sockets.\n");
 854
 855   fail ();
 856 }
 857
 858 #else /* HAVE_SOCKETS */
 859
 860 #include <sys/types.h>
 861 #include <sys/socket.h>
 862 #include <sys/un.h>
 863 #include <sys/stat.h>
 864 #include <errno.h>
 865
 866 extern char *strerror ();
 867 extern int errno;
 868
 869 /* Three possibilities:
 870    2 - can't be `stat'ed                (sets errno)
 871    1 - isn't owned by us
 872    0 - success: none of the above */
 873
 874 static int
 875 socket_status (socket_name)
 876      char *socket_name;
 877 {
 878   struct stat statbfr;
 879
 880   if (stat (socket_name, &statbfr) == -1)
 881     return 2;
 882
 883   if (statbfr.st_uid != geteuid ())
 884     return 1;
 885
 886   return 0;
 887 }
 888
 889 int
 890 main (argc, argv)
 891      int argc;
 892      char **argv;
 893 {
 894   char *system_name;
 895   int system_name_length;
 896   int s, i, needlf = 0;
 897   FILE *out, *in;
 898   struct sockaddr_un server;
 899   char *cwd, *str;
 900   char string[BUFSIZ];
 901
 902   main_argc = argc;
 903   main_argv = argv;
 904   progname = argv[0];
 905
 906   /* Process options.  */
 907   decode_options (argc, argv);
 908
 909   if ((argc - optind < 1) && !eval && !frame)
 910     {
 911       fprintf (stderr, "%s: file name or argument required\n", progname);
 912       fprintf (stderr, "Try `%s --help' for more information\n", progname);
 913       exit (1);
 914     }
 915
 916   /*
 917    * Open up an AF_UNIX socket in this person's home directory
 918    */
 919
 920   if ((s = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
 921     {
 922       fprintf (stderr, "%s: ", argv[0]);
 923       perror ("socket");
 924       fail ();
 925     }
 926
 927   server.sun_family = AF_UNIX;
 928
 929   {
 930     char *dot;
 931     system_name_length = 32;
 932
 933     while (1)
 934       {
 935         system_name = (char *) xmalloc (system_name_length + 1);
 936
 937         /* system_name must be null-terminated string.  */
 938         system_name[system_name_length] = '\0';
 939
 940         if (gethostname (system_name, system_name_length) == 0)
 941           break;
 942
 943         free (system_name);
 944         system_name_length *= 2;
 945       }
 946
 947     /* We always use the non-dotted host name, for simplicity.  */
 948     dot = index (system_name, '.');
 949     if (dot)
 950       *dot = '\0';
 951   }
 952
 953   {
 954     int sock_status = 0;
 955     int oerrno = 0;
 956
 957     if (! socket_name)
 958       {
 959         socket_name = alloca (system_name_length + 100);
 960         sprintf (socket_name, "/tmp/emacs%d-%s/server",
 961                  (int) geteuid (), system_name);
 962       }
 963
 964     if (strlen (socket_name) < sizeof (server.sun_path))
 965       strcpy (server.sun_path, socket_name);
 966     else
 967       {
 968         fprintf (stderr, "%s: socket-name %s too long",
 969                  argv[0], socket_name);
 970         fail ();
 971       }
 972
 973     /* See if the socket exists, and if it's owned by us. */
 974     sock_status = socket_status (server.sun_path);
 975     oerrno = errno;
 976     if (sock_status)
 977       {
 978         /* Failing that, see if LOGNAME or USER exist and differ from
 979            our euid.  If so, look for a socket based on the UID
 980            associated with the name.  This is reminiscent of the logic
 981            that init_editfns uses to set the global Vuser_full_name.  */
 982
 983         char *user_name = (char *) getenv ("LOGNAME");
 984         if (!user_name)
 985           user_name = (char *) getenv ("USER");
 986
 987         if (user_name)
 988           {
 989             struct passwd *pw = getpwnam (user_name);
 990             if (pw && (pw->pw_uid != geteuid ()))
 991               {
 992                 /* We're running under su, apparently. */
 993                 sprintf (server.sun_path, "/tmp/esrv%d-%s",
 994                          (int) pw->pw_uid, system_name);
 995                 sock_status = socket_status (server.sun_path);
 996                 oerrno = errno;
 997               }
 998           }
 999       }
1000
1001      switch (sock_status)
1002        {
1003        case 1:
1004          /* There's a socket, but it isn't owned by us.  This is OK if
1005             we are root. */
1006          if (0 != geteuid ())
1007            {
1008              fprintf (stderr, "%s: Invalid socket owner\n", argv[0]);
1009              fail ();
1010            }
1011          break;
1012
1013        case 2:
1014          /* `stat' failed */
1015          if (errno == ENOENT)
1016            fprintf (stderr,
1017                     "%s: Can't find socket; have you started the server?\n\
1018 To start the server in Emacs, type \"M-x server-start\".\n",
1019                     argv[0]);
1020          else
1021            fprintf (stderr, "%s: Can't stat %s: %s\n",
1022                     argv[0], server.sun_path, strerror (oerrno));
1023          fail ();
1024          break;
1025        }
1026   }
1027
1028   if (connect (s, (struct sockaddr *) &server, strlen (server.sun_path) + 2)
1029       < 0)
1030     {
1031       fprintf (stderr, "%s: ", argv[0]);
1032       perror ("connect");
1033       fail ();
1034     }
1035
1036   /* We use the stream OUT to send our command to the server.  */
1037   if ((out = fdopen (s, "r+")) == NULL)
1038     {
1039       fprintf (stderr, "%s: ", argv[0]);
1040       perror ("fdopen");
1041       fail ();
1042     }
1043
1044   /* We use the stream IN to read the response.
1045      We used to use just one stream for both output and input
1046      on the socket, but reversing direction works nonportably:
1047      on some systems, the output appears as the first input;
1048      on other systems it does not.  */
1049   if ((in = fdopen (s, "r+")) == NULL)
1050     {
1051       fprintf (stderr, "%s: ", argv[0]);
1052       perror ("fdopen");
1053       fail ();
1054     }
1055
1056 #ifdef HAVE_GETCWD
1057   cwd = getcwd (string, sizeof string);
1058 #else
1059   cwd = getwd (string);
1060 #endif
1061   if (cwd == 0)
1062     {
1063       /* getwd puts message in STRING if it fails.  */
1064
1065 #ifdef HAVE_GETCWD
1066       fprintf (stderr, "%s: %s (%s)\n", argv[0],
1067                "Cannot get current working directory", strerror (errno));
1068 #else
1069       fprintf (stderr, "%s: %s (%s)\n", argv[0], string, strerror (errno));
1070 #endif
1071       fail ();
1072     }
1073
1074   if (nowait)
1075     fprintf (out, "-nowait ");
1076
1077   if (eval)
1078     fprintf (out, "-eval ");
1079
1080   if (display)
1081     {
1082       fprintf (out, "-display ");
1083       quote_file_name (display, out);
1084       fprintf (out, " ");
1085     }
1086
1087   if (frame)
1088     {
1089       if (! init_signals ())
1090         {
1091           fprintf (stderr, "%s: ", argv[0]);
1092           perror ("fdopen");
1093           fail ();
1094         }
1095
1096       if (! init_tty ())
1097         {
1098           reset_tty ();
1099           fprintf (stderr, "%s: ", argv[0]);
1100           perror ("fdopen");
1101           fail ();
1102         }
1103
1104       if (! init_pty ())
1105         {
1106           reset_tty ();
1107           fprintf (stderr, "%s: ", argv[0]);
1108           perror ("fdopen");
1109           fail ();
1110         }
1111
1112       fprintf (out, "-tty ");
1113       quote_file_name (pty_name, out);
1114       fprintf (out, " ");
1115       quote_file_name (getenv("TERM"), out);
1116       fprintf (out, " ");
1117     }
1118
1119   if ((argc - optind > 0))
1120     {
1121       for (i = optind; i < argc; i++)
1122         {
1123           if (eval)
1124             ; /* Don't prepend any cwd or anything like that.  */
1125           else if (*argv[i] == '+')
1126             {
1127               char *p = argv[i] + 1;
1128               while (isdigit ((unsigned char) *p) || *p == ':') p++;
1129               if (*p != 0)
1130                 {
1131                   quote_file_name (cwd, out);
1132                   fprintf (out, "/");
1133                 }
1134             }
1135           else if (*argv[i] != '/')
1136             {
1137               quote_file_name (cwd, out);
1138               fprintf (out, "/");
1139             }
1140
1141           quote_file_name (argv[i], out);
1142           fprintf (out, " ");
1143         }
1144     }
1145   else
1146     {
1147       if (!frame)
1148         {
1149           while ((str = fgets (string, BUFSIZ, stdin)))
1150             {
1151               quote_file_name (str, out);
1152             }
1153           fprintf (out, " ");
1154         }
1155     }
1156
1157   fprintf (out, "\n");
1158   fflush (out);
1159
1160   /* Maybe wait for an answer.   */
1161   if (nowait)
1162     {
1163       reset_tty ();
1164       return 0;
1165     }
1166
1167   if (frame)
1168     {
1169       if (! pty_conversation (out))
1170         {
1171           reset_tty ();
1172           fail ();
1173         }
1174       reset_tty ();
1175       return 0;
1176     }
1177
1178   if (!eval)
1179     {
1180       printf ("Waiting for Emacs...");
1181       needlf = 2;
1182     }
1183   fflush (stdout);
1184
1185   /* Now, wait for an answer and print any messages.  */
1186   while ((str = fgets (string, BUFSIZ, in)))
1187     {
1188       if (needlf == 2)
1189         printf ("\n");
1190       printf ("%s", str);
1191       needlf = str[0] == '\0' ? needlf : str[strlen (str) - 1] != '\n';
1192     }
1193
1194   if (needlf)
1195     printf ("\n");
1196   fflush (stdout);
1197
1198   reset_tty ();
1199   return 0;
1200 }
1201
1202 #endif /* HAVE_SOCKETS */
1203 \f
1204 #ifndef HAVE_STRERROR
1205 char *
1206 strerror (errnum)
1207      int errnum;
1208 {
1209   extern char *sys_errlist[];
1210   extern int sys_nerr;
1211
1212   if (errnum >= 0 && errnum < sys_nerr)
1213     return sys_errlist[errnum];
1214   return (char *) "Unknown error";
1215 }
1216
1217 #endif /* ! HAVE_STRERROR */
1218
1219 /* arch-tag: f39bb9c4-73eb-477e-896d-50832e2ca9a7
1220    (do not change this comment) */