libguile/ioext.c

   1 /*      Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2006, 2011 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public License
   5  * as published by the Free Software Foundation; either version 3 of
   6  * the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301 USA
  17  */
  18
  19
  20 \f
  21
  22 #ifdef HAVE_CONFIG_H
  23 #  include <config.h>
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <errno.h>
  28
  29 #include "libguile/_scm.h"
  30 #include "libguile/dynwind.h"
  31 #include "libguile/feature.h"
  32 #include "libguile/fports.h"
  33 #include "libguile/hashtab.h"
  34 #include "libguile/ioext.h"
  35 #include "libguile/ports.h"
  36 #include "libguile/strings.h"
  37 #include "libguile/validate.h"
  38
  39 #include <fcntl.h>
  40
  41 #ifdef HAVE_IO_H
  42 #include <io.h>
  43 #endif
  44 #ifdef HAVE_UNISTD_H
  45 #include <unistd.h>
  46 #endif
  47 \f
  48
  49 SCM_DEFINE (scm_ftell, "ftell", 1, 0, 0,
  50             (SCM fd_port),
  51             "Return an integer representing the current position of\n"
  52             "@var{fd/port}, measured from the beginning.  Equivalent to:\n"
  53             "\n"
  54             "@lisp\n"
  55             "(seek port 0 SEEK_CUR)\n"
  56             "@end lisp")
  57 #define FUNC_NAME s_scm_ftell
  58 {
  59   return scm_seek (fd_port, SCM_INUM0, scm_from_int (SEEK_CUR));
  60 }
  61 #undef FUNC_NAME
  62
  63 SCM_DEFINE (scm_redirect_port, "redirect-port", 2, 0, 0,
  64             (SCM old, SCM new),
  65             "This procedure takes two ports and duplicates the underlying file\n"
  66             "descriptor from @var{old-port} into @var{new-port}.  The\n"
  67             "current file descriptor in @var{new-port} will be closed.\n"
  68             "After the redirection the two ports will share a file position\n"
  69             "and file status flags.\n\n"
  70             "The return value is unspecified.\n\n"
  71             "Unexpected behaviour can result if both ports are subsequently used\n"
  72             "and the original and/or duplicate ports are buffered.\n\n"
  73             "This procedure does not have any side effects on other ports or\n"
  74             "revealed counts.")
  75 #define FUNC_NAME s_scm_redirect_port
  76 {
  77   int ans, oldfd, newfd;
  78   scm_t_fport *fp;
  79
  80   old = SCM_COERCE_OUTPORT (old);
  81   new = SCM_COERCE_OUTPORT (new);
  82
  83   SCM_VALIDATE_OPFPORT (1, old);
  84   SCM_VALIDATE_OPFPORT (2, new);
  85   oldfd = SCM_FPORT_FDES (old);
  86   fp = SCM_FSTREAM (new);
  87   newfd = fp->fdes;
  88   if (oldfd != newfd)
  89     {
  90       scm_t_port *pt = SCM_PTAB_ENTRY (new);
  91       scm_t_port *old_pt = SCM_PTAB_ENTRY (old);
  92       scm_t_ptob_descriptor *ptob = SCM_PORT_DESCRIPTOR (new);
  93
  94       /* must flush to old fdes.  */
  95       if (pt->rw_active == SCM_PORT_WRITE)
  96         ptob->flush (new);
  97       else if (pt->rw_active == SCM_PORT_READ)
  98         scm_end_input_unlocked (new);
  99       ans = dup2 (oldfd, newfd);
 100       if (ans == -1)
 101         SCM_SYSERROR;
 102       pt->rw_random = old_pt->rw_random;
 103       /* continue using existing buffers, even if inappropriate.  */
 104     }
 105   return SCM_UNSPECIFIED;
 106 }
 107 #undef FUNC_NAME
 108
 109 SCM_DEFINE (scm_dup_to_fdes, "dup->fdes", 1, 1, 0,
 110             (SCM fd_or_port, SCM fd),
 111             "Return a new integer file descriptor referring to the open file\n"
 112             "designated by @var{fd_or_port}, which must be either an open\n"
 113             "file port or a file descriptor.")
 114 #define FUNC_NAME s_scm_dup_to_fdes
 115 {
 116   int oldfd, newfd, rv;
 117
 118   fd_or_port = SCM_COERCE_OUTPORT (fd_or_port);
 119
 120   if (scm_is_integer (fd_or_port))
 121     oldfd = scm_to_int (fd_or_port);
 122   else
 123     {
 124       SCM_VALIDATE_OPFPORT (1, fd_or_port);
 125       oldfd = SCM_FPORT_FDES (fd_or_port);
 126     }
 127
 128   if (SCM_UNBNDP (fd))
 129     {
 130       newfd = dup (oldfd);
 131       if (newfd == -1)
 132         SCM_SYSERROR;
 133       fd = scm_from_int (newfd);
 134     }
 135   else
 136     {
 137       newfd = scm_to_int (fd);
 138       if (oldfd != newfd)
 139         {
 140           scm_evict_ports (newfd);      /* see scsh manual.  */
 141           rv = dup2 (oldfd, newfd);
 142           if (rv == -1)
 143             SCM_SYSERROR;
 144         }
 145     }
 146   return fd;
 147 }
 148 #undef FUNC_NAME
 149
 150
 151 SCM_DEFINE (scm_dup2, "dup2", 2, 0, 0,
 152             (SCM oldfd, SCM newfd),
 153             "A simple wrapper for the @code{dup2} system call.\n"
 154             "Copies the file descriptor @var{oldfd} to descriptor\n"
 155             "number @var{newfd}, replacing the previous meaning\n"
 156             "of @var{newfd}.  Both @var{oldfd} and @var{newfd} must\n"
 157             "be integers.\n"
 158             "Unlike for dup->fdes or primitive-move->fdes, no attempt\n"
 159             "is made to move away ports which are using @var{newfd}.\n"
 160             "The return value is unspecified.")
 161 #define FUNC_NAME s_scm_dup2
 162 {
 163   int c_oldfd;
 164   int c_newfd;
 165   int rv;
 166
 167   c_oldfd = scm_to_int (oldfd);
 168   c_newfd = scm_to_int (newfd);
 169   rv = dup2 (c_oldfd, c_newfd);
 170   if (rv == -1)
 171     SCM_SYSERROR;
 172   return SCM_UNSPECIFIED;
 173 }
 174 #undef FUNC_NAME
 175
 176 SCM_DEFINE (scm_fileno, "fileno", 1, 0, 0,
 177             (SCM port),
 178             "Return the integer file descriptor underlying @var{port}.  Does\n"
 179             "not change its revealed count.")
 180 #define FUNC_NAME s_scm_fileno
 181 {
 182   port = SCM_COERCE_OUTPORT (port);
 183   SCM_VALIDATE_OPFPORT (1, port);
 184   return scm_from_int (SCM_FPORT_FDES (port));
 185 }
 186 #undef FUNC_NAME
 187
 188 /* GJB:FIXME:: why does this not throw
 189    an error if the arg is not a port?
 190    This proc as is would be better names isattyport?
 191    if it is not going to assume that the arg is a port
 192
 193    [cmm] I don't see any problem with the above.  why should a type
 194    predicate assume _anything_ about its argument?
 195 */
 196 SCM_DEFINE (scm_isatty_p, "isatty?", 1, 0, 0,
 197             (SCM port),
 198             "Return @code{#t} if @var{port} is using a serial non--file\n"
 199             "device, otherwise @code{#f}.")
 200 #define FUNC_NAME s_scm_isatty_p
 201 {
 202   int rv;
 203
 204   port = SCM_COERCE_OUTPORT (port);
 205
 206   if (!SCM_OPFPORTP (port))
 207     return SCM_BOOL_F;
 208
 209   rv = isatty (SCM_FPORT_FDES (port));
 210   return  scm_from_bool(rv);
 211 }
 212 #undef FUNC_NAME
 213
 214
 215
 216 SCM_DEFINE (scm_fdopen, "fdopen", 2, 0, 0,
 217             (SCM fdes, SCM modes),
 218             "Return a new port based on the file descriptor @var{fdes}.\n"
 219             "Modes are given by the string @var{modes}.  The revealed count\n"
 220             "of the port is initialized to zero.  The modes string is the\n"
 221             "same as that accepted by @ref{File Ports, open-file}.")
 222 #define FUNC_NAME s_scm_fdopen
 223 {
 224   return scm_i_fdes_to_port (scm_to_int (fdes),
 225                              scm_i_mode_bits (modes), SCM_BOOL_F);
 226 }
 227 #undef FUNC_NAME
 228
 229
 230
 231 /* Move a port's underlying file descriptor to a given value.
 232  * Returns  #f if fdes is already the given value.
 233  *          #t if fdes moved.
 234  * MOVE->FDES is implemented in Scheme and calls this primitive.
 235  */
 236 SCM_DEFINE (scm_primitive_move_to_fdes, "primitive-move->fdes", 2, 0, 0,
 237             (SCM port, SCM fd),
 238             "Moves the underlying file descriptor for @var{port} to the integer\n"
 239             "value @var{fdes} without changing the revealed count of @var{port}.\n"
 240             "Any other ports already using this descriptor will be automatically\n"
 241             "shifted to new descriptors and their revealed counts reset to zero.\n"
 242             "The return value is @code{#f} if the file descriptor already had the\n"
 243             "required value or @code{#t} if it was moved.")
 244 #define FUNC_NAME s_scm_primitive_move_to_fdes
 245 {
 246   scm_t_fport *stream;
 247   int old_fd;
 248   int new_fd;
 249   int rv;
 250
 251   port = SCM_COERCE_OUTPORT (port);
 252
 253   SCM_VALIDATE_OPFPORT (1, port);
 254   stream = SCM_FSTREAM (port);
 255   old_fd = stream->fdes;
 256   new_fd = scm_to_int (fd);
 257   if  (old_fd == new_fd)
 258     {
 259       return SCM_BOOL_F;
 260     }
 261   scm_evict_ports (new_fd);
 262   rv = dup2 (old_fd, new_fd);
 263   if (rv == -1)
 264     SCM_SYSERROR;
 265   stream->fdes = new_fd;
 266   SCM_SYSCALL (close (old_fd));
 267   return SCM_BOOL_T;
 268 }
 269 #undef FUNC_NAME
 270
 271 static SCM
 272 get_matching_port (void *closure, SCM port, SCM result)
 273 {
 274   int fd = * (int *) closure;
 275   scm_t_port *entry = SCM_PTAB_ENTRY (port);
 276
 277   if (SCM_OPFPORTP (port)
 278       && ((scm_t_fport *) entry->stream)->fdes == fd)
 279     result = scm_cons (port, result);
 280
 281   return result;
 282 }
 283
 284 /* Return a list of ports using a given file descriptor.  */
 285 SCM_DEFINE (scm_fdes_to_ports, "fdes->ports", 1, 0, 0,
 286            (SCM fd),
 287             "Return a list of existing ports which have @var{fdes} as an\n"
 288             "underlying file descriptor, without changing their revealed\n"
 289             "counts.")
 290 #define FUNC_NAME s_scm_fdes_to_ports
 291 {
 292   SCM result = SCM_EOL;
 293   int int_fd = scm_to_int (fd);
 294
 295   result = scm_c_weak_set_fold (get_matching_port,
 296                                 (void*) &int_fd, result,
 297                                 scm_i_port_weak_set);
 298   return result;
 299 }
 300 #undef FUNC_NAME
 301
 302
 303 void
 304 scm_init_ioext ()
 305 {
 306   scm_add_feature ("i/o-extensions");
 307
 308 #include "libguile/ioext.x"
 309 }
 310
 311
 312 /*
 313   Local Variables:
 314   c-file-style: "gnu"
 315   End:
 316 */