gcc/fixinc/procopen.c

   1
   2 /*
   3  *  server.c  Set up and handle communications with a server process.
   4  *
   5  *  Server Handling copyright 1992-1999 The Free Software Foundation
   6  *
   7  *  Server Handling is free software.
   8  *  You may redistribute it and/or modify it under the terms of the
   9  *  GNU General Public License, as published by the Free Software
  10  *  Foundation; either version 2, or (at your option) any later version.
  11  *
  12  *  Server Handling 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 Server Handling.  See the file "COPYING".  If not,
  19  *  write to:  The Free Software Foundation, Inc.,
  20  *             59 Temple Place - Suite 330,
  21  *             Boston,  MA  02111-1307, USA.
  22  *
  23  * As a special exception, The Free Software Foundation gives
  24  * permission for additional uses of the text contained in his release
  25  * of ServerHandler.
  26  *
  27  * The exception is that, if you link the ServerHandler library with other
  28  * files to produce an executable, this does not by itself cause the
  29  * resulting executable to be covered by the GNU General Public License.
  30  * Your use of that executable is in no way restricted on account of
  31  * linking the ServerHandler library code into it.
  32  *
  33  * This exception does not however invalidate any other reasons why
  34  * the executable file might be covered by the GNU General Public License.
  35  *
  36  * This exception applies only to the code released by The Free
  37  * Software Foundation under the name ServerHandler.  If you copy code
  38  * from other sources under the General Public License into a copy of
  39  * ServerHandler, as the General Public License permits, the exception
  40  * does not apply to the code that you add in this way.  To avoid
  41  * misleading anyone as to the status of such modified files, you must
  42  * delete this exception notice from them.
  43  *
  44  * If you write modifications of your own for ServerHandler, it is your
  45  * choice whether to permit this exception to apply to your modifications.
  46  * If you do not wish that, delete this exception notice.
  47  */
  48 #include "auto-host.h"
  49 #include "gansidecl.h"
  50 #include "system.h"
  51
  52 #include "server.h"
  53
  54 /* If this particular system's header files define the macro `MAXPATHLEN',
  55    we happily take advantage of it; otherwise we use a value which ought
  56    to be large enough.  */
  57 #ifndef MAXPATHLEN
  58 # define MAXPATHLEN     4096
  59 #endif
  60
  61 #ifndef STDIN_FILENO
  62 # define STDIN_FILENO   0
  63 #endif
  64 #ifndef STDOUT_FILENO
  65 # define STDOUT_FILENO  1
  66 #endif
  67
  68 #ifdef DEBUG
  69 #define STATIC
  70 #else
  71 #define STATIC static
  72 #endif
  73 #ifndef tSCC
  74 #define tSCC static const char
  75 #endif
  76 #ifndef NUL
  77 #define NUL '\0'
  78 #endif
  79
  80 STATIC t_pchar def_args[] =
  81 { (char *) NULL, (char *) NULL };
  82
  83 /*
  84  *  chain_open
  85  *
  86  *  Given an FD for an inferior process to use as stdin,
  87  *  start that process and return a NEW FD that that process
  88  *  will use for its stdout.  Requires the argument vector
  89  *  for the new process and, optionally, a pointer to a place
  90  *  to store the child's process id.
  91  */
  92 int
  93 chain_open (stdin_fd, pp_args, p_child)
  94      int stdin_fd;
  95      t_pchar *pp_args;
  96      pid_t *p_child;
  97 {
  98   t_fd_pair stdout_pair;
  99   pid_t ch_id;
 100   char *pz_cmd;
 101
 102   stdout_pair.read_fd = stdout_pair.write_fd = -1;
 103
 104   /*
 105    *  Create a pipe it will be the child process' stdout,
 106    *  and the parent will read from it.
 107    */
 108   if (pipe ((int *) &stdout_pair) < 0)
 109     {
 110       if (p_child != (pid_t *) NULL)
 111         *p_child = NOPROCESS;
 112       return -1;
 113     }
 114
 115   /*
 116    *  If we did not get an arg list, use the default
 117    */
 118   if (pp_args == (t_pchar *) NULL)
 119     pp_args = def_args;
 120
 121   /*
 122    *  If the arg list does not have a program,
 123    *  assume the "SHELL" from the environment, or, failing
 124    *  that, then sh.  Set argv[0] to whatever we decided on.
 125    */
 126   if (pz_cmd = *pp_args,
 127       (pz_cmd == (char *) NULL) || (*pz_cmd == '\0'))
 128     {
 129
 130       pz_cmd = getenv ("SHELL");
 131       if (pz_cmd == (char *) NULL)
 132         pz_cmd = "sh";
 133     }
 134
 135 #ifdef DEBUG_PRINT
 136   printf ("START:  %s\n", pz_cmd);
 137   {
 138     int idx = 0;
 139
 140     while (pp_args[++idx] != (char *) NULL)
 141       printf ("  ARG %2d:  %s\n", idx, pp_args[idx]);
 142   }
 143 #endif
 144
 145   /*
 146    *  Call fork() and see which process we become
 147    */
 148   ch_id = fork ();
 149   switch (ch_id)
 150     {
 151     case NOPROCESS:             /* parent - error in call */
 152       close (stdout_pair.read_fd);
 153       close (stdout_pair.write_fd);
 154       if (p_child != (pid_t *) NULL)
 155         *p_child = NOPROCESS;
 156       return -1;
 157
 158     default:                    /* parent - return opposite FD's */
 159       if (p_child != (pid_t *) NULL)
 160         *p_child = ch_id;
 161 #ifdef DEBUG_PRINT
 162       printf ("for pid %d:  stdin from %d, stdout to %d\n"
 163               "for parent:  read from %d\n",
 164               ch_id, stdin_fd, stdout_pair.write_fd, stdout_pair.read_fd);
 165 #endif
 166       close (stdin_fd);
 167       close (stdout_pair.write_fd);
 168       return stdout_pair.read_fd;
 169
 170     case NULLPROCESS:           /* child - continue processing */
 171       break;
 172     }
 173
 174   /*
 175    *  Close the pipe end handed back to the parent process
 176    */
 177   close (stdout_pair.read_fd);
 178
 179   /*
 180    *  Close our current stdin and stdout
 181    */
 182   close (STDIN_FILENO);
 183   close (STDOUT_FILENO);
 184
 185   /*
 186    *  Make the fd passed in the stdin, and the write end of
 187    *  the new pipe become the stdout.
 188    */
 189   fcntl (stdout_pair.write_fd, F_DUPFD, STDOUT_FILENO);
 190   fcntl (stdin_fd, F_DUPFD, STDIN_FILENO);
 191
 192   if (*pp_args == (char *) NULL)
 193     *pp_args = pz_cmd;
 194
 195   execvp (pz_cmd, pp_args);
 196   fprintf (stderr, "Error %d:  Could not execvp( '%s', ... ):  %s\n",
 197            errno, pz_cmd, xstrerror (errno));
 198   exit (EXIT_PANIC);
 199 }
 200
 201
 202 /*
 203  *  proc2_open
 204  *
 205  *  Given a pointer to an argument vector, start a process and
 206  *  place its stdin and stdout file descriptors into an fd pair
 207  *  structure.  The "write_fd" connects to the inferior process
 208  *  stdin, and the "read_fd" connects to its stdout.  The calling
 209  *  process should write to "write_fd" and read from "read_fd".
 210  *  The return value is the process id of the created process.
 211  */
 212 pid_t
 213 proc2_open (p_pair, pp_args)
 214      t_fd_pair *p_pair;
 215      t_pchar *pp_args;
 216 {
 217   pid_t ch_id;
 218
 219   /*  Create a bi-directional pipe.  Writes on 0 arrive on 1 and vice
 220      versa, so the parent and child processes will read and write to
 221      opposite FD's.  */
 222   if (pipe ((int *) p_pair) < 0)
 223     return NOPROCESS;
 224
 225   p_pair->read_fd = chain_open (p_pair->read_fd, pp_args, &ch_id);
 226   if (ch_id == NOPROCESS)
 227     close (p_pair->write_fd);
 228
 229   return ch_id;
 230 }
 231
 232
 233 /*
 234  *  proc2_fopen
 235  *
 236  *  Identical to "proc2_open()", except that the "fd"'s are
 237  *  "fdopen(3)"-ed into file pointers instead.
 238  */
 239 pid_t
 240 proc2_fopen (pf_pair, pp_args)
 241      t_pf_pair *pf_pair;
 242      t_pchar *pp_args;
 243 {
 244   t_fd_pair fd_pair;
 245   pid_t ch_id = proc2_open (&fd_pair, pp_args);
 246
 247   if (ch_id == NOPROCESS)
 248     return ch_id;
 249
 250   pf_pair->pf_read = fdopen (fd_pair.read_fd, "r");
 251   pf_pair->pf_write = fdopen (fd_pair.write_fd, "w");
 252   return ch_id;
 253 }