pipe.c

ｂｏａ：著名嵌入式系统网页服务器源代码。

/*
 *  Boa, an http server
 *  Based on code Copyright (C) 1995 Paul Phillips <[e-mail]>
 *  Some changes Copyright (C) 1997-99 Jon Nelson <[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 1, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

/* $Id: pipe.c,v 1.39 2002/01/21 02:19:16 jnelson Exp $*/

#include "boa.h"

/*
 * Name: read_from_pipe
 * Description: Reads data from a pipe
 *
 * Return values:
 *  -1: request blocked, move to blocked queue
 *   0: EOF or error, close it down
 *   1: successful read, recycle in ready queue
 */

int read_from_pipe(request * req)
{
    int bytes_read, bytes_to_read =
        BUFFER_SIZE - (req->header_end - req->buffer);

    if (bytes_to_read == 0) {   /* buffer full */
        if (req->cgi_status == CGI_PARSE) { /* got+parsed header */
            req->cgi_status = CGI_BUFFER;
            *req->header_end = '\0'; /* points to end of read data */
            /* Could the above statement overwrite data???
               No, because req->header_end points to where new data
               should begin, not where old data is.
             */
            return process_cgi_header(req); /* cgi_status will change */
        }
        req->status = PIPE_WRITE;
        return 1;
    }

    bytes_read = read(req->data_fd, req->header_end, bytes_to_read);
#ifdef FASCIST_LOGGING
    if (bytes_read > 0) {
        *(req->header_end + bytes_read) = '\0';
        fprintf(stderr, "pipe.c - read %d bytes: \"%s\"\n",
                bytes_read, req->header_end);
    } else
        fprintf(stderr, "pipe.c - read %d bytes\n", bytes_read);
    fprintf(stderr, "status, cgi_status: %d, %d\n", req->status,
            req->cgi_status);
#endif

    if (bytes_read == -1) {
        if (errno == EINTR)
            return 1;
        else if (errno == EWOULDBLOCK || errno == EAGAIN)
            return -1;          /* request blocked at the pipe level, but keep going */
        else {
	    req->status = DEAD;
            log_error_doc(req);
            perror("pipe read");
            return 0;
        }
    } else if (bytes_read == 0) { /* eof, write rest of buffer */
        req->status = PIPE_WRITE;
        if (req->cgi_status == CGI_PARSE) { /* hasn't processed header yet */
            req->cgi_status = CGI_DONE;
            *req->header_end = '\0'; /* points to end of read data */
            return process_cgi_header(req); /* cgi_status will change */
        }
        req->cgi_status = CGI_DONE;
        return 1;
    }
    req->header_end += bytes_read;
    return 1;
}

/*
 * Name: write_from_pipe
 * Description: Writes data previously read from a pipe
 *
 * Return values:
 *  -1: request blocked, move to blocked queue
 *   0: EOF or error, close it down
 *   1: successful write, recycle in ready queue
 */

int write_from_pipe(request * req)
{
    int bytes_written, bytes_to_write = req->header_end - req->header_line;

    if (bytes_to_write == 0) {
        if (req->cgi_status == CGI_DONE)
            return 0;

        req->status = PIPE_READ;
        req->header_end = req->header_line = req->buffer;
        return 1;
    }

    bytes_written = write(req->fd, req->header_line, bytes_to_write);

    if (bytes_written == -1) {
        if (errno == EWOULDBLOCK || errno == EAGAIN)
            return -1;          /* request blocked at the pipe level, but keep going */
        else if (errno == EINTR)
            return 1;
        else {
            req->status = DEAD;
            send_r_error(req);  /* maybe superfluous */
            log_error_doc(req);
            perror("pipe write");
            return 0;
        }
    }

    req->header_line += bytes_written;
    req->filepos += bytes_written;

    return 1;
}