libguile/ioext.c

   1 /* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2006,
   2  *   2011, 2014 Free Software Foundation, Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public License
   6  * as published by the Free Software Foundation; either version 3 of
   7  * the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301 USA
  18  */
  19
  20
  21 \f
  22
  23 #ifdef HAVE_CONFIG_H
  24 #  include <config.h>
  25 #endif
  26
  27 #include <stdio.h>
  28 #include <errno.h>
  29
  30 #include "libguile/_scm.h"
  31 #include "libguile/dynwind.h"
  32 #include "libguile/feature.h"
  33 #include "libguile/fports.h"
  34 #include "libguile/hashtab.h"
  35 #include "libguile/ioext.h"
  36 #include "libguile/ports.h"
  37 #include "libguile/strings.h"
  38 #include "libguile/validate.h"
  39
  40 #include <fcntl.h>
  41
  42 #ifdef HAVE_IO_H
  43 #include <io.h>
  44 #endif
  45 #include <unistd.h>
  46 \f
  47
  48 SCM_DEFINE (scm_ftell, "ftell", 1, 0, 0,
  49             (SCM fd_port),
  50             "Return an integer representing the current position of\n"
  51             "@var{fd_port}, measured from the beginning.  Equivalent to:\n"
  52             "\n"
  53             "@lisp\n"
  54             "(seek port 0 SEEK_CUR)\n"
  55             "@end lisp")
  56 #define FUNC_NAME s_scm_ftell
  57 {
  58   return scm_seek (fd_port, SCM_INUM0, scm_from_int (SEEK_CUR));
  59 }
  60 #undef FUNC_NAME
  61
  62 SCM_DEFINE (scm_redirect_port, "redirect-port", 2, 0, 0,
  63             (SCM old, SCM new),
  64             "This procedure takes two ports and duplicates the underlying file\n"
  65             "descriptor from @var{old} into @var{new}.  The\n"
  66             "current file descriptor in @var{new} will be closed.\n"
  67             "After the redirection the two ports will share a file position\n"
  68             "and file status flags.\n\n"
  69             "The return value is unspecified.\n\n"
  70             "Unexpected behaviour can result if both ports are subsequently used\n"
  71             "and the original and/or duplicate ports are buffered.\n\n"
  72             "This procedure does not have any side effects on other ports or\n"
  73             "revealed counts.")
  74 #define FUNC_NAME s_scm_redirect_port
  75 {
  76   int ans, oldfd, newfd;
  77   scm_t_fport *fp;
  78
  79   old = SCM_COERCE_OUTPORT (old);
  80   new = SCM_COERCE_OUTPORT (new);
  81
  82   SCM_VALIDATE_OPFPORT (1, old);
  83   SCM_VALIDATE_OPFPORT (2, new);
  84   oldfd = SCM_FPORT_FDES (old);
  85   fp = SCM_FSTREAM (new);
  86   newfd = fp->fdes;
  87   if (oldfd != newfd)
  88     {
  89       scm_t_port *pt = SCM_PTAB_ENTRY (new);
  90       scm_t_port *old_pt = SCM_PTAB_ENTRY (old);
  91       scm_t_ptob_descriptor *ptob = SCM_PORT_DESCRIPTOR (new);
  92
  93       /* must flush to old fdes.  */
  94       if (pt->rw_active == SCM_PORT_WRITE)
  95         ptob->flush (new);
  96       else if (pt->rw_active == SCM_PORT_READ)
  97         scm_end_input_unlocked (new);
  98       ans = dup2 (oldfd, newfd);
  99       if (ans == -1)
 100         SCM_SYSERROR;
 101       pt->rw_random = old_pt->rw_random;
 102       /* continue using existing buffers, even if inappropriate.  */
 103     }
 104   return SCM_UNSPECIFIED;
 105 }
 106 #undef FUNC_NAME
 107
 108 SCM_DEFINE (scm_dup_to_fdes, "dup->fdes", 1, 1, 0,
 109             (SCM fd_or_port, SCM fd),
 110             "Return a new integer file descriptor referring to the open file\n"
 111             "designated by @var{fd_or_port}, which must be either an open\n"
 112             "file port or a file descriptor.")
 113 #define FUNC_NAME s_scm_dup_to_fdes
 114 {
 115   int oldfd, newfd, rv;
 116
 117   fd_or_port = SCM_COERCE_OUTPORT (fd_or_port);
 118
 119   if (scm_is_integer (fd_or_port))
 120     oldfd = scm_to_int (fd_or_port);
 121   else
 122     {
 123       SCM_VALIDATE_OPFPORT (1, fd_or_port);
 124       oldfd = SCM_FPORT_FDES (fd_or_port);
 125     }
 126
 127   if (SCM_UNBNDP (fd))
 128     {
 129       newfd = dup (oldfd);
 130       if (newfd == -1)
 131         SCM_SYSERROR;
 132       fd = scm_from_int (newfd);
 133     }
 134   else
 135     {
 136       newfd = scm_to_int (fd);
 137       if (oldfd != newfd)
 138         {
 139           scm_evict_ports (newfd);      /* see scsh manual.  */
 140           rv = dup2 (oldfd, newfd);
 141           if (rv == -1)
 142             SCM_SYSERROR;
 143         }
 144     }
 145   return fd;
 146 }
 147 #undef FUNC_NAME
 148
 149
 150 SCM_DEFINE (scm_dup2, "dup2", 2, 0, 0,
 151             (SCM oldfd, SCM newfd),
 152             "A simple wrapper for the @code{dup2} system call.\n"
 153             "Copies the file descriptor @var{oldfd} to descriptor\n"
 154             "number @var{newfd}, replacing the previous meaning\n"
 155             "of @var{newfd}.  Both @var{oldfd} and @var{newfd} must\n"
 156             "be integers.\n"
 157             "Unlike for dup->fdes or primitive-move->fdes, no attempt\n"
 158             "is made to move away ports which are using @var{newfd}.\n"
 159             "The return value is unspecified.")
 160 #define FUNC_NAME s_scm_dup2
 161 {
 162   int c_oldfd;
 163   int c_newfd;
 164   int rv;
 165
 166   c_oldfd = scm_to_int (oldfd);
 167   c_newfd = scm_to_int (newfd);
 168   rv = dup2 (c_oldfd, c_newfd);
 169   if (rv == -1)
 170     SCM_SYSERROR;
 171   return SCM_UNSPECIFIED;
 172 }
 173 #undef FUNC_NAME
 174
 175 SCM_DEFINE (scm_fileno, "fileno", 1, 0, 0,
 176             (SCM port),
 177             "Return the integer file descriptor underlying @var{port}.  Does\n"
 178             "not change its revealed count.")
 179 #define FUNC_NAME s_scm_fileno
 180 {
 181   port = SCM_COERCE_OUTPORT (port);
 182   SCM_VALIDATE_OPFPORT (1, port);
 183   return scm_from_int (SCM_FPORT_FDES (port));
 184 }
 185 #undef FUNC_NAME
 186
 187 /* GJB:FIXME:: why does this not throw
 188    an error if the arg is not a port?
 189    This proc as is would be better names isattyport?
 190    if it is not going to assume that the arg is a port
 191
 192    [cmm] I don't see any problem with the above.  why should a type
 193    predicate assume _anything_ about its argument?
 194 */
 195 SCM_DEFINE (scm_isatty_p, "isatty?", 1, 0, 0,
 196             (SCM port),
 197             "Return @code{#t} if @var{port} is using a serial non--file\n"
 198             "device, otherwise @code{#f}.")
 199 #define FUNC_NAME s_scm_isatty_p
 200 {
 201   int rv;
 202
 203   port = SCM_COERCE_OUTPORT (port);
 204
 205   if (!SCM_OPFPORTP (port))
 206     return SCM_BOOL_F;
 207
 208   rv = isatty (SCM_FPORT_FDES (port));
 209   return  scm_from_bool(rv);
 210 }
 211 #undef FUNC_NAME
 212
 213
 214
 215 SCM_DEFINE (scm_fdopen, "fdopen", 2, 0, 0,
 216             (SCM fdes, SCM modes),
 217             "Return a new port based on the file descriptor @var{fdes}.\n"
 218             "Modes are given by the string @var{modes}.  The revealed count\n"
 219             "of the port is initialized to zero.  The modes string is the\n"
 220             "same as that accepted by @ref{File Ports, open-file}.")
 221 #define FUNC_NAME s_scm_fdopen
 222 {
 223   return scm_i_fdes_to_port (scm_to_int (fdes),
 224                              scm_i_mode_bits (modes), SCM_BOOL_F);
 225 }
 226 #undef FUNC_NAME
 227
 228
 229
 230 /* Move a port's underlying file descriptor to a given value.
 231  * Returns  #f if fdes is already the given value.
 232  *          #t if fdes moved.
 233  * MOVE->FDES is implemented in Scheme and calls this primitive.
 234  */
 235 SCM_DEFINE (scm_primitive_move_to_fdes, "primitive-move->fdes", 2, 0, 0,
 236             (SCM port, SCM fd),
 237             "Moves the underlying file descriptor for @var{port} to the integer\n"
 238             "value @var{fd} without changing the revealed count of @var{port}.\n"
 239             "Any other ports already using this descriptor will be automatically\n"
 240             "shifted to new descriptors and their revealed counts reset to zero.\n"
 241             "The return value is @code{#f} if the file descriptor already had the\n"
 242             "required value or @code{#t} if it was moved.")
 243 #define FUNC_NAME s_scm_primitive_move_to_fdes
 244 {
 245   scm_t_fport *stream;
 246   int old_fd;
 247   int new_fd;
 248   int rv;
 249
 250   port = SCM_COERCE_OUTPORT (port);
 251
 252   SCM_VALIDATE_OPFPORT (1, port);
 253   stream = SCM_FSTREAM (port);
 254   old_fd = stream->fdes;
 255   new_fd = scm_to_int (fd);
 256   if  (old_fd == new_fd)
 257     {
 258       return SCM_BOOL_F;
 259     }
 260   scm_evict_ports (new_fd);
 261   rv = dup2 (old_fd, new_fd);
 262   if (rv == -1)
 263     SCM_SYSERROR;
 264   stream->fdes = new_fd;
 265   SCM_SYSCALL (close (old_fd));
 266   return SCM_BOOL_T;
 267 }
 268 #undef FUNC_NAME
 269
 270 static SCM
 271 get_matching_port (void *closure, SCM port, SCM result)
 272 {
 273   int fd = * (int *) closure;
 274   scm_t_port *entry = SCM_PTAB_ENTRY (port);
 275
 276   if (SCM_OPFPORTP (port)
 277       && ((scm_t_fport *) entry->stream)->fdes == fd)
 278     result = scm_cons (port, result);
 279
 280   return result;
 281 }
 282
 283 /* Return a list of ports using a given file descriptor.  */
 284 SCM_DEFINE (scm_fdes_to_ports, "fdes->ports", 1, 0, 0,
 285            (SCM fd),
 286             "Return a list of existing ports which have @var{fd} as an\n"
 287             "underlying file descriptor, without changing their revealed\n"
 288             "counts.")
 289 #define FUNC_NAME s_scm_fdes_to_ports
 290 {
 291   SCM result = SCM_EOL;
 292   int int_fd = scm_to_int (fd);
 293
 294   result = scm_c_weak_set_fold (get_matching_port,
 295                                 (void*) &int_fd, result,
 296                                 scm_i_port_weak_set);
 297   return result;
 298 }
 299 #undef FUNC_NAME
 300
 301
 302 void
 303 scm_init_ioext ()
 304 {
 305   scm_add_feature ("i/o-extensions");
 306
 307 #include "libguile/ioext.x"
 308 }
 309
 310
 311 /*
 312   Local Variables:
 313   c-file-style: "gnu"
 314   End:
 315 */