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::connection::~connection ()
  31 {
  32 }
  33
  34 void
  35 cc1_plugin::connection::print (const char *)
  36 {
  37 }
  38
  39 cc1_plugin::status
  40 cc1_plugin::connection::send (char c)
  41 {
  42   if (write (m_fd, &c, 1) != 1)
  43     return FAIL;
  44   return OK;
  45 }
  46
  47 cc1_plugin::status
  48 cc1_plugin::connection::send (const void *buf, int len)
  49 {
  50   if (write (m_fd, buf, len) != len)
  51     return FAIL;
  52   return OK;
  53 }
  54
  55 cc1_plugin::status
  56 cc1_plugin::connection::require (char c)
  57 {
  58   char result;
  59
  60   if (read (m_fd, &result, 1) != 1
  61       || result != c)
  62     return FAIL;
  63
  64   return OK;
  65 }
  66
  67 cc1_plugin::status
  68 cc1_plugin::connection::get (void *buf, int len)
  69 {
  70   if (read (m_fd, buf, len) != len)
  71     return FAIL;
  72   return OK;
  73 }
  74
  75 cc1_plugin::status
  76 cc1_plugin::connection::do_wait (bool want_result)
  77 {
  78   while (true)
  79     {
  80       char result;
  81       fd_set read_set;
  82
  83       FD_ZERO (&read_set);
  84       FD_SET (m_fd, &read_set);
  85       if (m_aux_fd != -1)
  86         FD_SET (m_aux_fd, &read_set);
  87
  88       int nfds = select (FD_SETSIZE, &read_set, NULL, NULL, NULL);
  89       if (nfds == -1)
  90         {
  91           if (errno == EINTR)
  92             continue;
  93           return FAIL;
  94         }
  95
  96       // We have to check the stderr fd first, to avoid a possible
  97       // blocking scenario when do_wait is called reentrantly.  In
  98       // such a call, if we handle the primary fd first, then we may
  99       // re-enter this function, read from gcc's stderr, causing the
 100       // outer invocation of this function to block when trying to
 101       // read.
 102       if (m_aux_fd != -1 && FD_ISSET (m_aux_fd, &read_set))
 103         {
 104           char buf[1024];
 105           int n = read (m_aux_fd, buf, sizeof (buf) - 1);
 106           if (n < 0)
 107             return FAIL;
 108           if (n > 0)
 109             {
 110               buf[n] = '\0';
 111               print (buf);
 112             }
 113         }
 114
 115       if (FD_ISSET (m_fd, &read_set))
 116         {
 117           int n = read (m_fd, &result, 1);
 118           if (n == 0)
 119             return want_result ? FAIL : OK;
 120           if (n != 1)
 121             return FAIL;
 122
 123           switch (result)
 124             {
 125             case 'R':
 126               // The reply is ready; the caller will unmarshall it.
 127               return want_result ? OK : FAIL;
 128
 129             case 'Q':
 130               // While waiting for a reply, the other side made a method
 131               // call.
 132               {
 133                 // Use an argument_wrapper here to simplify management
 134                 // of the string's lifetime.
 135                 argument_wrapper<char *> method_name;
 136
 137                 if (!method_name.unmarshall (this))
 138                   return FAIL;
 139
 140                 callback_ftype *callback
 141                   = m_callbacks.find_callback (method_name);
 142                 // The call to CALLBACK is where we may end up in a
 143                 // reentrant call.
 144                 if (callback == NULL || !callback (this))
 145                   return FAIL;
 146               }
 147               break;
 148
 149             default:
 150               return FAIL;
 151             }
 152         }
 153     }
 154 }