libcc1/connection.cc

   1 /* Connect implementation
   2    Copyright (C) 2014-2021 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include <cc1plugin-config.h>
  21 #include <string>
  22 #include <unistd.h>
  23 #include <sys/types.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include "marshall.hh"
  27 #include "connection.hh"
  28 #include "rpc.hh"
  29
  30 cc1_plugin::status
  31 cc1_plugin::connection::send (char c)
  32 {
  33   if (write (m_fd, &c, 1) != 1)
  34     return FAIL;
  35   return OK;
  36 }
  37
  38 cc1_plugin::status
  39 cc1_plugin::connection::send (const void *buf, int len)
  40 {
  41   if (write (m_fd, buf, len) != len)
  42     return FAIL;
  43   return OK;
  44 }
  45
  46 cc1_plugin::status
  47 cc1_plugin::connection::require (char c)
  48 {
  49   char result;
  50
  51   if (read (m_fd, &result, 1) != 1
  52       || result != c)
  53     return FAIL;
  54
  55   return OK;
  56 }
  57
  58 cc1_plugin::status
  59 cc1_plugin::connection::get (void *buf, int len)
  60 {
  61   if (read (m_fd, buf, len) != len)
  62     return FAIL;
  63   return OK;
  64 }
  65
  66 cc1_plugin::status
  67 cc1_plugin::connection::do_wait (bool want_result)
  68 {
  69   while (true)
  70     {
  71       char result;
  72       fd_set read_set;
  73
  74       FD_ZERO (&read_set);
  75       FD_SET (m_fd, &read_set);
  76       if (m_aux_fd != -1)
  77         FD_SET (m_aux_fd, &read_set);
  78
  79       int nfds = select (FD_SETSIZE, &read_set, NULL, NULL, NULL);
  80       if (nfds == -1)
  81         {
  82           if (errno == EINTR)
  83             continue;
  84           return FAIL;
  85         }
  86
  87       // We have to check the stderr fd first, to avoid a possible
  88       // blocking scenario when do_wait is called reentrantly.  In
  89       // such a call, if we handle the primary fd first, then we may
  90       // re-enter this function, read from gcc's stderr, causing the
  91       // outer invocation of this function to block when trying to
  92       // read.
  93       if (m_aux_fd != -1 && FD_ISSET (m_aux_fd, &read_set))
  94         {
  95           char buf[1024];
  96           int n = read (m_aux_fd, buf, sizeof (buf) - 1);
  97           if (n < 0)
  98             return FAIL;
  99           if (n > 0)
 100             {
 101               buf[n] = '\0';
 102               print (buf);
 103             }
 104         }
 105
 106       if (FD_ISSET (m_fd, &read_set))
 107         {
 108           int n = read (m_fd, &result, 1);
 109           if (n == 0)
 110             return want_result ? FAIL : OK;
 111           if (n != 1)
 112             return FAIL;
 113
 114           switch (result)
 115             {
 116             case 'R':
 117               // The reply is ready; the caller will unmarshall it.
 118               return want_result ? OK : FAIL;
 119
 120             case 'Q':
 121               // While waiting for a reply, the other side made a method
 122               // call.
 123               {
 124                 // Use an argument_wrapper here to simplify management
 125                 // of the string's lifetime.
 126                 argument_wrapper<char *> method_name;
 127
 128                 if (!method_name.unmarshall (this))
 129                   return FAIL;
 130
 131                 callback_ftype *callback
 132                   = m_callbacks.find_callback (method_name.get ());
 133                 // The call to CALLBACK is where we may end up in a
 134                 // reentrant call.
 135                 if (callback == NULL || !callback (this))
 136                   return FAIL;
 137               }
 138               break;
 139
 140             default:
 141               return FAIL;
 142             }
 143         }
 144     }
 145 }