/****************************************************************************
* netutils/thttpd/cgi-src/redirect.c
* Simple redirection CGI program
*
* Copyright (C) 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Derived from the file of the same name in the original THTTPD package:
*
* Copyright � 1995 by Jef Poskanzer <jef@mail.acme.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
****************************************************************************/
/* Three steps to set up a redirection:
*
* 1. Make sure your web server is set up to allow CGI programs.
* 2. Make a symbolic link from the file you want to redirect,
* pointing at this program in the CGI bin directory.
* 3. Add an entry to the file ".redirects" in the directory where your
* http server runs CGI programs. For most servers, this is the
* directory where the given CGI program lives. The format of the
* file is a bunch of lines with a filename, whitespace, and the new
* URL. For example:
*
* /test/oldfile.html http://www.acme.com/test/newfile.html
*
* The easiest way to figure out precisely what filename to put into
* .redirects is to set up the symlink and then click on it. You'll get
* back a "404 Not Found" page which includes the filename as received by
* the redirect program, and that's what you want to use.
*
* Note: this is designed for thttpd (http://www.acme.com/software/thttpd/)
* and using it with other web servers may require some hacking. A possible
* gotcha is with the symbolic link from the old file pointing at this
* script - servers other than thttpd may not allow that link to be run
* as a CGI program, because they don't check the link to see that it
* points into the allowed CGI directory.
*
* Note two: It would be really cool to have this program look for
* the .redirects file in the same directory as the file being redirected,
* instead of in the binaries directory. Unfortunately, this appears
* to be impossible with the information CGI gives, plus the non-standardized
* but widespread practice of running CGI programs in the directory where
* the binary lives. Perhaps CGI 1.2 will address this.
*/
/****************************************************************************
* Public Functions
****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "config.h"
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
#define LINE_SIZE 80
/****************************************************************************
* Private Data
****************************************************************************/
static char g_iobuffer[LINE_SIZE];
static char g_file[LINE_SIZE];
static char g_url[LINE_SIZE];
/****************************************************************************
* Private Functions
****************************************************************************/
static void internal_error(char *reason)
{
char *title = "500 Internal Error";
(void)printf("\
Status: %s\n\
Content-type: text/html\n\
\n\
<HTML><HEAD><TITLE>%s</TITLE></HEAD>\n\
<BODY><H2>%s</H2>\n\
Something unusual went wrong during a redirection request:\n\
<BLOCKQUOTE>\n\
%s\n\
</BLOCKQUOTE>\n\
</BODY></HTML>\n", title, title, title, reason);
}
static void not_found(char *script_name)
{
char *title = "404 Not Found";
(void)printf("\
Status: %s\n\
Content-type: text/html\n\
\n\
<HTML><HEAD><TITLE>%s</TITLE></HEAD>\n\
<BODY><H2>%s</H2>\n\
The requested filename, %s, is set up to be redirected to another URL;\n\
however, the new URL has not yet been specified.\n\
</BODY></HTML>\n", title, title, title, script_name);
}
static void moved(char *script_name, char *url)
{
char *title = "Moved";
(void)printf("\
Location: %s\n\
Content-type: text/html\n\
\n\
<HTML><HEAD><TITLE>%s</TITLE></HEAD>\n\
<BODY><H2>%s</H2>\n\
The requested filename, %s, has moved to a new URL:\n\
<A HREF=\"%s\">%s</A>.\n\
</BODY></HTML>\n", url, title, title, script_name, url, url);
}
/****************************************************************************
* Public Functions
****************************************************************************/
int main(int argc, char **argv)
{
char *script_name;
char *path_info;
char *cp = 0;
FILE *fp;
char *star;
int err = 0;
/* Get the name that we were run as, which is the filename being **
* redirected.
*/
script_name = getenv("SCRIPT_NAME");
if (!script_name)
{
internal_error("Couldn't get SCRIPT_NAME environment variable.");
return 1;
}
/* Append the PATH_INFO, if any. This allows redirection of whole **
* directories.
*/
path_info = getenv("PATH_INFO");
if (path_info)
{
cp = (char *)malloc(strlen(script_name) + strlen(path_info) + 1);
if (!cp)
{
internal_error("Out of memory.");
return 2;
}
(void)sprintf(cp, "%s%s", script_name, path_info);
script_name = cp;
}
/* Open the redirects file. */
fp = fopen(".redirects", "r");
if (fp == (FILE *) 0)
{
internal_error("Couldn't open .redirects file.");
err = 3;
goto errout_with_cp;
}
/* Search the file for a matching entry. */
while (fgets(g_iobuffer, LINE_SIZE, fp) != NULL)
{
/* Remove comments. */
cp = strchr(g_iobuffer, '#');
if (cp)
{
*cp = '\0';
}
/* Skip leading whitespace. */
cp = g_iobuffer;
cp += strspn(cp, " \t");
/* Check for blank line. */
if (*cp != '\0')
{
/* Parse line. */
if (sscanf(cp, "%[^ \t\n] %[^ \t\n]", g_file, g_url) == 2)
{
/* Check for wildcard match. */
star = strchr(g_file, '*');
if (star != (char *)0)
{
/* Check for leading match. */
if (strncmp(g_file, script_name, star - g_file) == 0)
{
/* Got it; put together the full name. */
strcat(g_url, script_name + (star - g_file));
/* XXX Whack the script_name, too? */
moved(script_name, g_url);
goto success_out;
}
}
/* Check for exact match. */
if (strcmp(g_file, script_name) == 0)
{
/* Got it. */
moved(script_name, g_url);
goto success_out;
}
}
}
}
/* No match found. */
not_found(script_name);
err = 4;
success_out:
fclose(fp);
errout_with_cp:
if (cp)
{
free(cp);
}
return err;
}
