cpp.c

distcc编译器的源代码.好像是readhat公司开发的.

/* -*- c-file-style: "java"; indent-tabs-mode: nil; fill-column: 78 -*-
 * 
 * distcc -- A simple distributed compiler system
 *
 * Copyright (C) 2002, 2003 by Martin Pool <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */

/**
 * @file
 *
 * Run the preprocessor.  Client-side only.
 **/

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include "distcc.h"
#include "trace.h"
#include "exitcode.h"
#include "util.h"
#include "implicit.h"
#include "exec.h"


/**
 * If the input filename is a plain source file rather than a
 * preprocessed source file, then preprocess it to a temporary file
 * and return the name in @p cpp_fname.
 *
 * The preprocessor may still be running when we return; you have to
 * wait for @p cpp_fid to exit before the output is complete.  This
 * allows us to overlap opening the TCP socket, which probably doesn't
 * use many cycles, with running the preprocessor.
 **/
int dcc_cpp_maybe(char **argv, char *input_fname, char **cpp_fname,
		  pid_t *cpp_pid)
{
    char **cpp_argv;
    int ret;
    char *input_exten;
    const char *output_exten;

    *cpp_pid = 0;
    
    if (dcc_is_preprocessed(input_fname)) {
        /* TODO: Perhaps also consider the option that says not to use cpp.
         * Would anyone do that? */
        rs_trace("input is already preprocessed");
        
        /* already preprocessed, great. */
        if (!(*cpp_fname = strdup(input_fname))) {
            rs_log_error("couldn't duplicate string");
            return EXIT_OUT_OF_MEMORY;
        }
        return 0;
    }

    input_exten = dcc_find_extension(input_fname);
    output_exten = dcc_preproc_exten(input_exten);
    if ((ret = dcc_make_tmpnam("distcc", output_exten, cpp_fname)))
        return ret;

    /* We strip the -o option and allow cpp to write to stdout, which is
     * caught in a file.  Sun cc doesn't understand -E -o, and gcc screws up
     * -MD -E -o.
     *
     * There is still a problem here with -MD -E -o, gcc writes dependencies
     * to a file determined by the source filename.  We could fix it by
     * generating a -MF option, but that would break compilation with older
     * versions of gcc.  This is only a problem for people who have the source
     * and objects in different directories, and who don't specify -MF.  They
     * can fix it by specifying -MF.  */
    
    if ((ret = dcc_strip_dasho(argv, &cpp_argv))
        || (ret = dcc_set_action_opt(cpp_argv, "-E")))
        return ret;

    /* FIXME: cpp_argv is leaked */

    return dcc_spawn_child(cpp_argv, cpp_pid,
                           "/dev/null", *cpp_fname, NULL);
}