root/trunk/lib-src/emacsclient.c

/* Client process that communicates with GNU Emacs acting as server.
   Copyright (C) 1986, 1987, 1994, 1999, 2000, 2001, 2002, 2003, 2004,
                 2005, 2006, 2007, 2008 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */


#define NO_SHORTNAMES

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef WINDOWSNT

/* config.h defines these, which disables sockets altogether! */
# undef _WINSOCKAPI_
# undef _WINSOCK_H

# include <malloc.h>
# include <stdlib.h>
# include <windows.h>
# include <commctrl.h>

# define NO_SOCKETS_IN_FILE_SYSTEM

# define HSOCKET SOCKET
# define CLOSE_SOCKET closesocket
# define INITIALIZE() (initialize_sockets ())

#else /* !WINDOWSNT */

# include <sys/types.h>

# ifdef HAVE_INET_SOCKETS
#  include <netinet/in.h>
# endif

# define INVALID_SOCKET -1
# define HSOCKET int
# define CLOSE_SOCKET close
# define INITIALIZE()

#endif /* !WINDOWSNT */

#undef signal

#include <stdarg.h>
#include <ctype.h>
#include <stdio.h>
#include "getopt.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef VMS
# include "vms-pwd.h"
#else /* not VMS */
#ifdef WINDOWSNT
# include <io.h>
#else /* not WINDOWSNT */
# include <pwd.h>
#endif /* not WINDOWSNT */
#endif /* not VMS */

char *getenv (), *getwd ();
char *(getcwd) ();

#ifdef WINDOWSNT
char *w32_getenv ();
#define egetenv(VAR) w32_getenv(VAR)
#else
#define egetenv(VAR) getenv(VAR)
#endif

#ifndef VERSION
#define VERSION "unspecified"
#endif

#define SEND_STRING(data) (send_to_emacs (s, (data)))
#define SEND_QUOTED(data) (quote_file_name (s, (data)))

#ifndef EXIT_SUCCESS
#define EXIT_SUCCESS 0
#endif

#ifndef EXIT_FAILURE
#define EXIT_FAILURE 1
#endif

#ifndef FALSE
#define FALSE 0
#endif

#ifndef TRUE
#define TRUE 1
#endif

#ifndef NO_RETURN
#define NO_RETURN
#endif

/* Name used to invoke this program.  */
char *progname;

/* Nonzero means don't wait for a response from Emacs.  --no-wait.  */
int nowait = 0;

/* Nonzero means args are expressions to be evaluated.  --eval.  */
int eval = 0;

/* The display on which Emacs should work.  --display.  */
char *display = NULL;

/* If non-NULL, the name of an editor to fallback to if the server
   is not running.  --alternate-editor.   */
const char *alternate_editor = NULL;

/* If non-NULL, the filename of the UNIX socket.  */
char *socket_name = NULL;

/* If non-NULL, the filename of the authentication file.  */
char *server_file = NULL;

/* PID of the Emacs server process.  */
int emacs_pid = 0;

void print_help_and_exit () NO_RETURN;

struct option longopts[] =
{
  { "no-wait",  no_argument,       NULL, 'n' },
  { "eval",     no_argument,       NULL, 'e' },
  { "help",     no_argument,       NULL, 'H' },
  { "version",  no_argument,       NULL, 'V' },
  { "alternate-editor", required_argument, NULL, 'a' },
#ifndef NO_SOCKETS_IN_FILE_SYSTEM
  { "socket-name",      required_argument, NULL, 's' },
#endif
  { "server-file",      required_argument, NULL, 'f' },
  { "display",  required_argument, NULL, 'd' },
  { 0, 0, 0, 0 }
};


/* Like malloc but get fatal error if memory is exhausted.  */

long *
xmalloc (size)
     unsigned int size;
{
  long *result = (long *) malloc (size);
  if (result == NULL)
    {
      perror ("malloc");
      exit (EXIT_FAILURE);
    }
  return result;
}

/* Message functions. */

#ifdef WINDOWSNT

#define REG_ROOT "SOFTWARE\\GNU\\Emacs"

/* Retrieve an environment variable from the Emacs subkeys of the registry.
   Return NULL if the variable was not found, or it was empty.
   This code is based on w32_get_resource (w32.c).  */
char *
w32_get_resource (predefined, key, type)
     HKEY predefined;
     char *key;
     LPDWORD type;
{
  HKEY hrootkey = NULL;
  char *result = NULL;
  DWORD cbData;

  if (RegOpenKeyEx (predefined, REG_ROOT, 0, KEY_READ, &hrootkey) == ERROR_SUCCESS)
    {
      if (RegQueryValueEx (hrootkey, key, NULL, NULL, NULL, &cbData) == ERROR_SUCCESS)
        {
          result = (char *) xmalloc (cbData);

          if ((RegQueryValueEx (hrootkey, key, NULL, type, result, &cbData) != ERROR_SUCCESS) ||
              (*result == 0))
            {
              free (result);
              result = NULL;
            }
        }

      RegCloseKey (hrootkey);
    }

  return result;
}

/*
  getenv wrapper for Windows

  This is needed to duplicate Emacs's behavior, which is to look for enviroment
  variables in the registry if they don't appear in the environment.
*/
char *
w32_getenv (envvar)
     char *envvar;
{
  char *value;
  DWORD dwType;

  if (value = getenv (envvar))
    /* Found in the environment.  */
    return value;

  if (! (value = w32_get_resource (HKEY_CURRENT_USER, envvar, &dwType)) &&
      ! (value = w32_get_resource (HKEY_LOCAL_MACHINE, envvar, &dwType)))
    /* Not found in the registry.  */
    return NULL;

  if (dwType == REG_SZ)
    /* Registry; no need to expand.  */
    return value;

  if (dwType == REG_EXPAND_SZ)
    {
      DWORD size;

      if (size = ExpandEnvironmentStrings (value, NULL, 0))
        {
          char *buffer = (char *) xmalloc (size);
          if (ExpandEnvironmentStrings (value, buffer, size))
            {
              /* Found and expanded.  */
              free (value);
              return buffer;
            }

          /* Error expanding.  */
          free (buffer);
        }
    }

  /* Not the right type, or not correctly expanded.  */
  free (value);
  return NULL;
}

int
w32_window_app ()
{
  static int window_app = -1;
  char szTitle[MAX_PATH];

  if (window_app < 0)
    {
      /* Checking for STDOUT does not work; it's a valid handle also in
         nonconsole apps.  Testing for the console title seems to work. */
      window_app = (GetConsoleTitleA (szTitle, MAX_PATH) == 0);
      if (window_app)
        InitCommonControls();
    }

  return window_app;
}
#endif

void
message (int is_error, char *message, ...)
{
  char msg [2048];
  va_list args;

  va_start (args, message);
  vsprintf (msg, message, args);
  va_end (args);

#ifdef WINDOWSNT
  if (w32_window_app ())
    {
      if (is_error)
        MessageBox (NULL, msg, "Emacsclient ERROR", MB_ICONERROR);
      else
        MessageBox (NULL, msg, "Emacsclient", MB_ICONINFORMATION);
    }
  else
#endif
    {
      FILE *f = is_error ? stderr : stdout;

      fputs (msg, f);
      fflush (f);
    }
}

/* Decode the options from argv and argc.
   The global variable `optind' will say how many arguments we used up.  */

void
decode_options (argc, argv)
     int argc;
     char **argv;
{
  alternate_editor = egetenv ("ALTERNATE_EDITOR");

  while (1)
    {
      int opt = getopt_long (argc, argv,
#ifndef NO_SOCKETS_IN_FILE_SYSTEM
                             "VHnea:s:f:d:",
#else
                             "VHnea:f:d:",
#endif
                             longopts, 0);

      if (opt == EOF)
        break;

      switch (opt)
        {
        case 0:
          /* If getopt returns 0, then it has already processed a
             long-named option.  We should do nothing.  */
          break;

        case 'a':
          alternate_editor = optarg;
          break;

#ifndef NO_SOCKETS_IN_FILE_SYSTEM
        case 's':
          socket_name = optarg;
          break;
#endif

        case 'f':
          server_file = optarg;
          break;

        case 'd':
          display = optarg;
          break;

        case 'n':
          nowait = 1;
          break;

        case 'e':
          eval = 1;
          break;

        case 'V':
          message (FALSE, "emacsclient %s\n", VERSION);
          exit (EXIT_SUCCESS);
          break;

        case 'H':
          print_help_and_exit ();
          break;

        default:
          message (TRUE, "Try `%s --help' for more information\n", progname);
          exit (EXIT_FAILURE);
          break;
        }
    }
}

void
print_help_and_exit ()
{
  message (FALSE,
          "Usage: %s [OPTIONS] FILE...\n\
Tell the Emacs server to visit the specified files.\n\
Every FILE can be either just a FILENAME or [+LINE[:COLUMN]] FILENAME.\n\
\n\
The following OPTIONS are accepted:\n\
\n\
-V, --version           Just print version info and return\n\
-H, --help              Print this usage information message\n\
-e, --eval              Evaluate FILE arguments as Lisp expressions\n\
-n, --no-wait           Don't wait for the server to return\n\
-d, --display=DISPLAY   Visit the file in the given display\n"
#ifndef NO_SOCKETS_IN_FILE_SYSTEM
"-s, --socket-name=FILENAME\n\
                        Set filename of the UNIX socket for communication\n"
#endif
"-f, --server-file=FILENAME\n\
                        Set filename of the TCP authentication file\n\
-a, --alternate-editor=EDITOR\n\
                        Editor to fallback to if server is not running\n\
\n\
Report bugs to bug-gnu-emacs@gnu.org.\n", progname);
  exit (EXIT_SUCCESS);
}


#ifdef WINDOWSNT

/*
  execvp wrapper for Windows. Quotes arguments with embedded spaces.

  This is necessary due to the broken implementation of exec* routines in
  the Microsoft libraries: they concatenate the arguments together without
  quoting special characters, and pass the result to CreateProcess, with
  predictably bad results.  By contrast, Posix execvp passes the arguments
  directly into the argv array of the child process.
*/
int
w32_execvp (path, argv)
     char *path;
     char **argv;
{
  int i;

  /* Required to allow a .BAT script as alternate editor.  */
  argv[0] = (char *) alternate_editor;

  for (i = 0; argv[i]; i++)
    if (strchr (argv[i], ' '))
      {
        char *quoted = alloca (strlen (argv[i]) + 3);
        sprintf (quoted, "\"%s\"", argv[i]);
        argv[i] = quoted;
      }

  return execvp (path, argv);
}

#undef execvp
#define execvp w32_execvp

#endif /* WINDOWSNT */

/*
  Try to run a different command, or --if no alternate editor is
  defined-- exit with an errorcode.
*/
void
fail (argc, argv)
     int argc;
     char **argv;
{
  if (alternate_editor)
    {
      int i = optind - 1;

      execvp (alternate_editor, argv + i);
      message (TRUE, "%s: error executing alternate editor \"%s\"\n",
               progname, alternate_editor);
    }
  exit (EXIT_FAILURE);
}


#if !defined (HAVE_SOCKETS) || !defined (HAVE_INET_SOCKETS)

int
main (argc, argv)
     int argc;
     char **argv;
{
  message (TRUE, "%s: Sorry, the Emacs server is supported only\non systems with Berkely sockets.\n",
           argv[0]);

  fail (argc, argv);
}

#else /* HAVE_SOCKETS && HAVE_INET_SOCKETS */

#ifdef WINDOWSNT
# include <winsock2.h>
#else
# include <sys/types.h>
# include <sys/socket.h>
# include <sys/un.h>
# include <sys/stat.h>
# include <errno.h>
#endif

#define AUTH_KEY_LENGTH      64
#define SEND_BUFFER_SIZE   4096

extern char *strerror ();
extern int errno;

/* Buffer to accumulate data to send in TCP connections.  */
char send_buffer[SEND_BUFFER_SIZE + 1];
int sblen = 0;  /* Fill pointer for the send buffer.  */

/* On Windows, the socket library was historically separate from the standard
   C library, so errors are handled differently.  */
void
sock_err_message (function_name)
     char *function_name;
{
#ifdef WINDOWSNT
  char* msg = NULL;

  FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM
                 | FORMAT_MESSAGE_ALLOCATE_BUFFER
                 | FORMAT_MESSAGE_ARGUMENT_ARRAY,
                 NULL, WSAGetLastError (), 0, (LPTSTR)&msg, 0, NULL);

  message (TRUE, "%s: %s: %s\n", progname, function_name, msg);

  LocalFree (msg);
#else
  message (TRUE, "%s: %s: %s\n", progname, function_name, strerror (errno));
#endif
}


/* Let's send the data to Emacs when either
   - the data ends in "\n", or
   - the buffer is full (but this shouldn't happen)
   Otherwise, we just accumulate it.  */
void
send_to_emacs (s, data)
     HSOCKET s;
     char *data;
{
  while (data)
    {
      int dlen = strlen (data);
      if (dlen + sblen >= SEND_BUFFER_SIZE)
        {
          int part = SEND_BUFFER_SIZE - sblen;
          strncpy (&send_buffer[sblen], data, part);
          data += part;
          sblen = SEND_BUFFER_SIZE;
        }
      else if (dlen)
        {
          strcpy (&send_buffer[sblen], data);
          data = NULL;
          sblen += dlen;
        }
      else
        break;

      if (sblen == SEND_BUFFER_SIZE
          || (sblen > 0 && send_buffer[sblen-1] == '\n'))
        {
          int sent = send (s, send_buffer, sblen, 0);
          if (sent != sblen)
            strcpy (send_buffer, &send_buffer[sent]);
          sblen -= sent;
        }
    }
}

/* In NAME, insert a & before each &, each space, each newline, and
   any initial -.  Change spaces to underscores, too, so that the
   return value never contains a space.  */
void
quote_file_name (s, name)
     HSOCKET s;
     char *name;
{
  char *copy = (char *) xmalloc (strlen (name) * 2 + 1);
  char *p, *q;

  p = name;
  q = copy;
  while (*p)
    {
      if (*p == ' ')
        {
          *q++ = '&';
          *q++ = '_';
          p++;
        }
      else if (*p == '\n')
        {
          *q++ = '&';
          *q++ = 'n';
          p++;
        }
      else
        {
          if (*p == '&' || (*p == '-' && p == name))
            *q++ = '&';
          *q++ = *p++;
        }
    }
  *q++ = 0;

  SEND_STRING (copy);

  free (copy);
}

int
file_name_absolute_p (filename)
     const unsigned char *filename;
{
  /* Sanity check, it shouldn't happen.  */
  if (! filename) return FALSE;

  /* /xxx is always an absolute path.  */
  if (filename[0] == '/') return TRUE;

  /* Empty filenames (which shouldn't happen) are relative.  */
  if (filename[0] == '\0') return FALSE;

#ifdef WINDOWSNT
  /* X:\xxx is always absolute.  */
  if (isalpha (filename[0])
      && filename[1] == ':' && (filename[2] == '\\' || filename[2] == '/'))
    return TRUE;

  /* Both \xxx and \\xxx\yyy are absolute.  */
  if (filename[0] == '\\') return TRUE;

  /*
    FIXME:  There's a corner case not dealt with, "x:y", where:

    1) x is a valid drive designation (usually a letter in the A-Z range)
       and y is a path, relative to the current directory on drive x.  This
       is absolute, *after* fixing the y part to include the current
       directory in x.

    2) x is a relative file name, and y is an NTFS stream name.  This is a
       correct relative path, but it is very unusual.

    The trouble is that first case items are also valid examples of the
    second case, i.e., "c:test" can be understood as drive:path or as
    file:stream.

    The "right" fix would involve checking whether
    - the current drive/partition is NTFS,
    - x is a valid (and accesible) drive designator,
    - x:y already exists as a file:stream in the current directory,
    - y already exists on the current directory of drive x,
    - the auspices are favorable,
    and then taking an "informed decision" based on the above.

    Whatever the result, Emacs currently does a very bad job of dealing
    with NTFS file:streams: it cannot visit them, and the only way to
    create one is by setting `buffer-file-name' to point to it (either
    manually or with emacsclient). So perhaps resorting to 1) and ignoring
    2) for now is the right thing to do.

    Anyway, something to decide After the Release.
  */
#endif

  return FALSE;
}

#ifdef WINDOWSNT
/* Wrapper to make WSACleanup a cdecl, as required by atexit.  */
void
__cdecl close_winsock ()
{
  WSACleanup ();
}

/* Initialize the WinSock2 library.  */
void
initialize_sockets ()
{
  WSADATA wsaData;

  if (WSAStartup (MAKEWORD (2, 0), &wsaData))
    {
      message (TRUE, "%s: error initializing WinSock2", progname);
      exit (EXIT_FAILURE);
    }

  atexit (close_winsock);
}
#endif /* WINDOWSNT */

/*
 * Read the information needed to set up a TCP comm channel with
 * the Emacs server: host, port, pid and authentication string.
 */
int
get_server_config (server, authentication)
     struct sockaddr_in *server;
     char *authentication;
{
  char dotted[32];
  char *port;
  char *pid;
  FILE *config = NULL;

  if (file_name_absolute_p (server_file))
    config = fopen (server_file, "rb");
  else
    {
      char *home = egetenv ("HOME");

      if (home)
        {
          char *path = alloca (32 + strlen (home