gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright 1999 Free Software Foundation, Inc.
   3
   4    Contributed by Cygnus Solutions.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "serial.h"
  25 #include <sys/types.h>
  26 #ifdef HAVE_SYS_WAIT_H
  27 #include <sys/wait.h>
  28 #endif
  29 #include <sys/socket.h>
  30 #include <sys/time.h>
  31 #include <fcntl.h>
  32
  33 #include "signals.h"
  34 #include "gdb_string.h"
  35
  36 extern int (*ui_loop_hook) PARAMS ((int));
  37
  38 static int pipe_open PARAMS ((serial_t scb, const char *name));
  39 static void pipe_raw PARAMS ((serial_t scb));
  40 static int wait_for PARAMS ((serial_t scb, int timeout));
  41 static int pipe_readchar PARAMS ((serial_t scb, int timeout));
  42 static int pipe_setbaudrate PARAMS ((serial_t scb, int rate));
  43 static int pipe_setstopbits PARAMS ((serial_t scb, int num));
  44 static int pipe_write PARAMS ((serial_t scb, const char *str, int len));
  45 /* FIXME: static void pipe_restore PARAMS ((serial_t scb)); */
  46 static void pipe_close PARAMS ((serial_t scb));
  47 static serial_ttystate pipe_get_tty_state PARAMS ((serial_t scb));
  48 static int pipe_set_tty_state PARAMS ((serial_t scb, serial_ttystate state));
  49 static int pipe_return_0 PARAMS ((serial_t));
  50 static int pipe_noflush_set_tty_state PARAMS ((serial_t, serial_ttystate,
  51                                                serial_ttystate));
  52 static void pipe_print_tty_state PARAMS ((serial_t, serial_ttystate));
  53
  54 extern void _initialize_ser_pipe PARAMS ((void));
  55
  56 #undef XMALLOC
  57 #define XMALLOC(T) ((T*) xmalloc (sizeof (T)))
  58
  59
  60 struct pipe_state
  61   {
  62     int pid;
  63   };
  64
  65 /* Open up a raw pipe */
  66
  67 static int
  68 pipe_open (scb, name)
  69      serial_t scb;
  70      const char *name;
  71 {
  72 #if !defined(O_NONBLOCK) || !defined(F_GETFL) || !defined(F_SETFL) || !HAVE_SOCKETPAIR
  73   return -1;
  74 #else
  75   struct pipe_state *state;
  76   /* This chunk: */
  77   /* Copyright (c) 1988, 1993
  78    *      The Regents of the University of California.  All rights reserved.
  79    *
  80    * This code is derived from software written by Ken Arnold and
  81    * published in UNIX Review, Vol. 6, No. 8.
  82    */
  83   int pdes[2];
  84   int pid;
  85   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  86     return -1;
  87
  88   pid = vfork ();
  89
  90   /* Error. */
  91   if (pid == -1)
  92     {
  93       close (pdes[0]);
  94       close (pdes[1]);
  95       return -1;
  96     }
  97
  98   /* Child. */
  99   if (pid == 0)
 100     {
 101       /* re-wire pdes[1] to stdin/stdout */
 102       close (pdes[0]);
 103       if (pdes[1] != STDOUT_FILENO)
 104         {
 105           dup2 (pdes[1], STDOUT_FILENO);
 106           close (pdes[1]);
 107         }
 108       dup2 (STDOUT_FILENO, STDIN_FILENO);
 109 #if 0
 110       /* close any stray FD's - FIXME - how? */
 111       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
 112          from previous popen() calls that remain open in the
 113          parent process are closed in the new child process. */
 114       for (old = pidlist; old; old = old->next)
 115         close (fileno (old->fp));       /* don't allow a flush */
 116 #endif
 117       execl ("/bin/sh", "sh", "-c", name + 1, NULL);
 118       _exit (127);
 119     }
 120
 121   /* Parent. */
 122   close (pdes[1]);
 123   /* :end chunk */
 124   state = XMALLOC (struct pipe_state);
 125   state->pid = pid;
 126   scb->fd = pdes[0];
 127   scb->state = state;
 128
 129   /* Make it non-blocking */
 130   {
 131     int flags = fcntl (scb->fd, F_GETFL, 0);
 132     if (fcntl (scb->fd, F_SETFL, flags | O_NONBLOCK) < 0)
 133       {
 134         perror ("ser-pipe");
 135         pipe_close (scb);
 136         return -1;
 137       }
 138   }
 139
 140   /* If we don't do this, GDB simply exits when the remote side dies.  */
 141   signal (SIGPIPE, SIG_IGN);
 142   return 0;
 143 #endif
 144 }
 145
 146 static serial_ttystate
 147 pipe_get_tty_state (scb)
 148      serial_t scb;
 149 {
 150   /* return garbage */
 151   return xmalloc (sizeof (int));
 152 }
 153
 154 static int
 155 pipe_set_tty_state (scb, ttystate)
 156      serial_t scb;
 157      serial_ttystate ttystate;
 158 {
 159   return 0;
 160 }
 161
 162 static int
 163 pipe_return_0 (scb)
 164      serial_t scb;
 165 {
 166   return 0;
 167 }
 168
 169 static void
 170 pipe_raw (scb)
 171      serial_t scb;
 172 {
 173   return;                       /* Always in raw mode */
 174 }
 175
 176 /* Wait for input on scb, with timeout seconds.  Returns 0 on success,
 177    otherwise SERIAL_TIMEOUT or SERIAL_ERROR.
 178
 179    For termio{s}, we actually just setup VTIME if necessary, and let the
 180    timeout occur in the read() in pipe_read().
 181  */
 182
 183 static int
 184 wait_for (scb, timeout)
 185      serial_t scb;
 186      int timeout;
 187 {
 188   int numfds;
 189   struct timeval tv;
 190   fd_set readfds, exceptfds;
 191
 192   FD_ZERO (&readfds);
 193   FD_ZERO (&exceptfds);
 194
 195   tv.tv_sec = timeout;
 196   tv.tv_usec = 0;
 197
 198   FD_SET (scb->fd, &readfds);
 199   FD_SET (scb->fd, &exceptfds);
 200
 201   while (1)
 202     {
 203       if (timeout >= 0)
 204         numfds = select (scb->fd + 1, &readfds, 0, &exceptfds, &tv);
 205       else
 206         numfds = select (scb->fd + 1, &readfds, 0, &exceptfds, 0);
 207
 208       if (numfds <= 0)
 209         {
 210           if (numfds == 0)
 211             return SERIAL_TIMEOUT;
 212           else if (errno == EINTR)
 213             continue;
 214           else
 215             return SERIAL_ERROR;        /* Got an error from select or poll */
 216         }
 217
 218       return 0;
 219     }
 220 }
 221
 222 /* Read a character with user-specified timeout.  TIMEOUT is number of seconds
 223    to wait, or -1 to wait forever.  Use timeout of 0 to effect a poll.  Returns
 224    char if successful.  Returns -2 if timeout expired, EOF if line dropped
 225    dead, or -3 for any other error (see errno in that case). */
 226
 227 static int
 228 pipe_readchar (scb, timeout)
 229      serial_t scb;
 230      int timeout;
 231 {
 232   int status;
 233   int delta;
 234
 235   if (scb->bufcnt-- > 0)
 236     return *scb->bufp++;
 237
 238   /* We have to be able to keep the GUI alive here, so we break the original
 239      timeout into steps of 1 second, running the "keep the GUI alive" hook
 240      each time through the loop.
 241
 242      Also, timeout = 0 means to poll, so we just set the delta to 0, so we
 243      will only go through the loop once. */
 244
 245   delta = (timeout == 0 ? 0 : 1);
 246   while (1)
 247     {
 248
 249       /* N.B. The UI may destroy our world (for instance by calling
 250          remote_stop,) in which case we want to get out of here as
 251          quickly as possible.  It is not safe to touch scb, since
 252          someone else might have freed it.  The ui_loop_hook signals that
 253          we should exit by returning 1. */
 254
 255       if (ui_loop_hook)
 256         {
 257           if (ui_loop_hook (0))
 258             return SERIAL_TIMEOUT;
 259         }
 260
 261       status = wait_for (scb, delta);
 262       timeout -= delta;
 263
 264       /* If we got a character or an error back from wait_for, then we can
 265          break from the loop before the timeout is completed. */
 266
 267       if (status != SERIAL_TIMEOUT)
 268         {
 269           break;
 270         }
 271
 272       /* If we have exhausted the original timeout, then generate
 273          a SERIAL_TIMEOUT, and pass it out of the loop. */
 274
 275       else if (timeout == 0)
 276         {
 277           status = SERIAL_TIMEOUT;
 278           break;
 279         }
 280     }
 281
 282   if (status < 0)
 283     return status;
 284
 285   while (1)
 286     {
 287       scb->bufcnt = read (scb->fd, scb->buf, BUFSIZ);
 288       if (scb->bufcnt != -1 || errno != EINTR)
 289         break;
 290     }
 291
 292   if (scb->bufcnt <= 0)
 293     {
 294       if (scb->bufcnt == 0)
 295         return SERIAL_TIMEOUT;  /* 0 chars means timeout [may need to
 296                                    distinguish between EOF & timeouts
 297                                    someday] */
 298       else
 299         return SERIAL_ERROR;    /* Got an error from read */
 300     }
 301
 302   scb->bufcnt--;
 303   scb->bufp = scb->buf;
 304   return *scb->bufp++;
 305 }
 306
 307 static int
 308 pipe_noflush_set_tty_state (scb, new_ttystate, old_ttystate)
 309      serial_t scb;
 310      serial_ttystate new_ttystate;
 311      serial_ttystate old_ttystate;
 312 {
 313   return 0;
 314 }
 315
 316 static void
 317 pipe_print_tty_state (scb, ttystate)
 318      serial_t scb;
 319      serial_ttystate ttystate;
 320 {
 321   /* Nothing to print.  */
 322   return;
 323 }
 324
 325 static int
 326 pipe_setbaudrate (scb, rate)
 327      serial_t scb;
 328      int rate;
 329 {
 330   return 0;                     /* Never fails! */
 331 }
 332
 333 static int
 334 pipe_setstopbits (scb, num)
 335      serial_t scb;
 336      int num;
 337 {
 338   return 0;                     /* Never fails! */
 339 }
 340
 341 static int
 342 pipe_write (scb, str, len)
 343      serial_t scb;
 344      const char *str;
 345      int len;
 346 {
 347   int cc;
 348
 349   while (len > 0)
 350     {
 351       cc = write (scb->fd, str, len);
 352
 353       if (cc < 0)
 354         return 1;
 355       len -= cc;
 356       str += cc;
 357     }
 358   return 0;
 359 }
 360
 361 static void
 362 pipe_close (scb)
 363      serial_t scb;
 364 {
 365   struct pipe_state *state = scb->state;
 366   if (state != NULL)
 367     {
 368       int pid = state->pid;
 369       close (scb->fd);
 370       scb->fd = -1;
 371       free (state);
 372       scb->state = NULL;
 373       kill (pid, SIGTERM);
 374       /* Might be useful to check that the child does die. */
 375     }
 376 }
 377
 378 static struct serial_ops pipe_ops =
 379 {
 380   "pipe",
 381   0,
 382   pipe_open,
 383   pipe_close,
 384   pipe_readchar,
 385   pipe_write,
 386   pipe_return_0,                /* flush output */
 387   pipe_return_0,                /* flush input */
 388   pipe_return_0,                /* send break */
 389   pipe_raw,
 390   pipe_get_tty_state,
 391   pipe_set_tty_state,
 392   pipe_print_tty_state,
 393   pipe_noflush_set_tty_state,
 394   pipe_setbaudrate,
 395   pipe_setstopbits,
 396   pipe_return_0,                /* wait for output to drain */
 397 };
 398
 399 void
 400 _initialize_ser_pipe ()
 401 {
 402   serial_add_interface (&pipe_ops);
 403 }