libcc1/connection.cc

   1 /* Connect implementation
   2    Copyright (C) 2014 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 <errno.h>
  25 #include "marshall.hh"
  26 #include "connection.hh"
  27 #include "rpc.hh"
  28
  29 cc1_plugin::connection::~connection ()
  30 {
  31 }
  32
  33 void
  34 cc1_plugin::connection::print (const char *)
  35 {
  36 }
  37
  38 cc1_plugin::status
  39 cc1_plugin::connection::send (char c)
  40 {
  41   if (write (m_fd, &c, 1) != 1)
  42     return FAIL;
  43   return OK;
  44 }
  45
  46 cc1_plugin::status
  47 cc1_plugin::connection::send (const void *buf, int len)
  48 {
  49   if (write (m_fd, buf, len) != len)
  50     return FAIL;
  51   return OK;
  52 }
  53
  54 cc1_plugin::status
  55 cc1_plugin::connection::require (char c)
  56 {
  57   char result;
  58
  59   if (read (m_fd, &result, 1) != 1
  60       || result != c)
  61     return FAIL;
  62
  63   return OK;
  64 }
  65
  66 cc1_plugin::status
  67 cc1_plugin::connection::get (void *buf, int len)
  68 {
  69   if (read (m_fd, buf, len) != len)
  70     return FAIL;
  71   return OK;
  72 }
  73
  74 cc1_plugin::status
  75 cc1_plugin::connection::do_wait (bool want_result)
  76 {
  77   while (true)
  78     {
  79       char result;
  80       fd_set read_set;
  81
  82       FD_ZERO (&read_set);
  83       FD_SET (m_fd, &read_set);
  84       if (m_aux_fd != -1)
  85         FD_SET (m_aux_fd, &read_set);
  86
  87       int nfds = select (FD_SETSIZE, &read_set, NULL, NULL, NULL);
  88       if (nfds == -1)
  89         {
  90           if (errno == EINTR)
  91             continue;
  92           return FAIL;
  93         }
  94
  95       // We have to check the stderr fd first, to avoid a possible
  96       // blocking scenario when do_wait is called reentrantly.  In
  97       // such a call, if we handle the primary fd first, then we may
  98       // re-enter this function, read from gcc's stderr, causing the
  99       // outer invocation of this function to block when trying to
 100       // read.
 101       if (m_aux_fd != -1 && FD_ISSET (m_aux_fd, &read_set))
 102         {
 103           char buf[1024];
 104           int n = read (m_aux_fd, buf, sizeof (buf) - 1);
 105           if (n < 0)
 106             return FAIL;
 107           if (n > 0)
 108             {
 109               buf[n] = '\0';
 110               print (buf);
 111             }
 112         }
 113
 114       if (FD_ISSET (m_fd, &read_set))
 115         {
 116           int n = read (m_fd, &result, 1);
 117           if (n == 0)
 118             return want_result ? FAIL : OK;
 119           if (n != 1)
 120             return FAIL;
 121
 122           switch (result)
 123             {
 124             case 'R':
 125               // The reply is ready; the caller will unmarshall it.
 126               return want_result ? OK : FAIL;
 127
 128             case 'Q':
 129               // While waiting for a reply, the other side made a method
 130               // call.
 131               {
 132                 // Use an argument_wrapper here to simplify management
 133                 // of the string's lifetime.
 134                 argument_wrapper<char *> method_name;
 135
 136                 if (!method_name.unmarshall (this))
 137                   return FAIL;
 138
 139                 callback_ftype *callback
 140                   = m_callbacks.find_callback (method_name);
 141                 // The call to CALLBACK is where we may end up in a
 142                 // reentrant call.
 143                 if (callback == NULL || !callback (this))
 144                   return FAIL;
 145               }
 146               break;
 147
 148             default:
 149               return FAIL;
 150             }
 151         }
 152     }
 153 }