thttpd/cgi-src/redirect.c

/* redirect - simple redirection CGI program
**
** Copyright © 1995 by Jef Poskanzer <jef@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.
*/

#include <sys/types.h>

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

#include "config.h"


static char* argv0;


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 );
    }
        

int
main( int argc, char** argv )
    {
    char* script_name;
    char* path_info;
    char* cp;
    FILE* fp;
    char *star;
    char buf[5000], file[5000], url[5000];

    argv0 = argv[0];

    /* Get the name that we were run as, which is the filename being
    ** redirected.
    */
    script_name = getenv( "SCRIPT_NAME" );
    if ( script_name == (char*) 0 )
        {
        internal_error( "Couldn't get SCRIPT_NAME environment variable." );
        exit( 1 );
        }

    /* Append the PATH_INFO, if any.  This allows redirection of whole
    ** directories.
    */
    path_info = getenv( "PATH_INFO" );
    if ( path_info != (char*) 0 )
        {
        cp = (char*) malloc( strlen( script_name ) + strlen( path_info ) + 1 );
        if ( cp == (char*) 0 )
            {
            internal_error( "Out of memory." );
            exit( 1 );
            }
        (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." );
        exit( 1 );
        }

    /* Search the file for a matching entry. */
    while ( fgets( buf, sizeof(buf), fp ) != (char*) 0 )
        {
        /* Remove comments. */
        cp = strchr( buf, '#' );
        if ( cp != (char*) 0 )
            *cp = '\0';
        /* Skip leading whitespace. */
        cp = buf;
        cp += strspn( cp, " \t" );
        /* Check for blank line. */
        if ( *cp != '\0' )
            {
            /* Parse line. */
            if ( sscanf( cp, "%[^ \t\n] %[^ \t\n]", file, url ) == 2 )
                {
                /* Check for wildcard match. */
                star = strchr( file, '*' );
                if ( star != (char*) 0 )
                    {
                    /* Check for leading match. */
                    if ( strncmp( file, script_name, star - file ) == 0 )
                        {
                        /* Got it; put together the full name. */
                        strcat( url, script_name + ( star - file ) );
                        /* XXX Whack the script_name, too? */
                        moved( script_name, url );
                        exit( 0 );
                        }
                    }
                /* Check for exact match. */
                if ( strcmp( file, script_name ) == 0 )
                    {
                    /* Got it. */
                    moved( script_name, url );
                    exit( 0 );
                    }
                }
            }
        }

    /* No match found. */
    not_found( script_name );
    exit( 1 );
    }
Revision:	1.1
Committed:	Mon Jun 18 21:11:58 2001 UTC (25 years, 3 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	mp_j, dp_j, cp_j, HEAD
Branch point for:	connpatch, dirpatch, mmapppatch
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/* redirect - simple redirection CGI program
2			**
3			** Copyright © 1995 by Jef Poskanzer <jef@acme.com>.
4			** All rights reserved.
5			**
6			** Redistribution and use in source and binary forms, with or without
7			** modification, are permitted provided that the following conditions
8			** are met:
9			** 1. Redistributions of source code must retain the above copyright
10			** notice, this list of conditions and the following disclaimer.
11			** 2. Redistributions in binary form must reproduce the above copyright
12			** notice, this list of conditions and the following disclaimer in the
13			** documentation and/or other materials provided with the distribution.
14			**
15			** THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16			** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17			** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18			** ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19			** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20			** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21			** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22			** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23			** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24			** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25			** SUCH DAMAGE.
26			*/
27
28			/* Three steps to set up a redirection:
29			** 1. Make sure your web server is set up to allow CGI programs.
30			** 2. Make a symbolic link from the file you want to redirect,
31			** pointing at this program in the CGI bin directory.
32			** 3. Add an entry to the file ".redirects" in the directory where your
33			** http server runs CGI programs. For most servers, this is the
34			** directory where the given CGI program lives. The format of the
35			** file is a bunch of lines with a filename, whitespace, and the new
36			** URL. For example:
37
38			/test/oldfile.html http://www.acme.com/test/newfile.html
39
40			** The easiest way to figure out precisely what filename to put into
41			** .redirects is to set up the symlink and then click on it. You'll get
42			** back a "404 Not Found" page which includes the filename as received by
43			** the redirect program, and that's what you want to use.
44			**
45			** Note: this is designed for thttpd (http://www.acme.com/software/thttpd/)
46			** and using it with other web servers may require some hacking. A possible
47			** gotcha is with the symbolic link from the old file pointing at this
48			** script - servers other than thttpd may not allow that link to be run
49			** as a CGI program, because they don't check the link to see that it
50			** points into the allowed CGI directory.
51			**
52			** Note two: It would be really cool to have this program look for
53			** the .redirects file in the same directory as the file being redirected,
54			** instead of in the binaries directory. Unfortunately, this appears
55			** to be impossible with the information CGI gives, plus the non-standardized
56			** but widespread practice of running CGI programs in the directory where
57			** the binary lives. Perhaps CGI 1.2 will address this.
58			*/
59
60			#include <sys/types.h>
61
62			#include <stdio.h>
63			#include <stdlib.h>
64			#include <string.h>
65
66			#include "config.h"
67
68
69			static char* argv0;
70
71
72			static void
73			internal_error( char* reason )
74			{
75			char* title = "500 Internal Error";
76
77			(void) printf( "\
78			Status: %s\n\
79			Content-type: text/html\n\
80			\n\
81			<HTML><HEAD><TITLE>%s</TITLE></HEAD>\n\
82			<BODY><H2>%s</H2>\n\
83			Something unusual went wrong during a redirection request:\n\
84			<BLOCKQUOTE>\n\
85			%s\n\
86			</BLOCKQUOTE>\n\
87			</BODY></HTML>\n", title, title, title, reason );
88			}
89
90
91			static void
92			not_found( char* script_name )
93			{
94			char* title = "404 Not Found";
95
96			(void) printf( "\
97			Status: %s\n\
98			Content-type: text/html\n\
99			\n\
100			<HTML><HEAD><TITLE>%s</TITLE></HEAD>\n\
101			<BODY><H2>%s</H2>\n\
102			The requested filename, %s, is set up to be redirected to another URL;\n\
103			however, the new URL has not yet been specified.\n\
104			</BODY></HTML>\n", title, title, title, script_name );
105			}
106
107
108			static void
109			moved( char* script_name, char* url )
110			{
111			char* title = "Moved";
112
113			(void) printf( "\
114			Location: %s\n\
115			Content-type: text/html\n\
116			\n\
117			<HTML><HEAD><TITLE>%s</TITLE></HEAD>\n\
118			<BODY><H2>%s</H2>\n\
119			The requested filename, %s, has moved to a new URL:\n\
120			<A HREF=\"%s\">%s</A>.\n\
121			</BODY></HTML>\n", url, title, title, script_name, url, url );
122			}
123
124
125			int
126			main( int argc, char** argv )
127			{
128			char* script_name;
129			char* path_info;
130			char* cp;
131			FILE* fp;
132			char *star;
133			char buf[5000], file[5000], url[5000];
134
135			argv0 = argv[0];
136
137			/* Get the name that we were run as, which is the filename being
138			** redirected.
139			*/
140			script_name = getenv( "SCRIPT_NAME" );
141			if ( script_name == (char*) 0 )
142			{
143			internal_error( "Couldn't get SCRIPT_NAME environment variable." );
144			exit( 1 );
145			}
146
147			/* Append the PATH_INFO, if any. This allows redirection of whole
148			** directories.
149			*/
150			path_info = getenv( "PATH_INFO" );
151			if ( path_info != (char*) 0 )
152			{
153			cp = (char*) malloc( strlen( script_name ) + strlen( path_info ) + 1 );
154			if ( cp == (char*) 0 )
155			{
156			internal_error( "Out of memory." );
157			exit( 1 );
158			}
159			(void) sprintf( cp, "%s%s", script_name, path_info );
160			script_name = cp;
161			}
162
163			/* Open the redirects file. */
164			fp = fopen( ".redirects", "r" );
165			if ( fp == (FILE*) 0 )
166			{
167			internal_error( "Couldn't open .redirects file." );
168			exit( 1 );
169			}
170
171			/* Search the file for a matching entry. */
172			while ( fgets( buf, sizeof(buf), fp ) != (char*) 0 )
173			{
174			/* Remove comments. */
175			cp = strchr( buf, '#' );
176			if ( cp != (char*) 0 )
177			*cp = '\0';
178			/* Skip leading whitespace. */
179			cp = buf;
180			cp += strspn( cp, " \t" );
181			/* Check for blank line. */
182			if ( *cp != '\0' )
183			{
184			/* Parse line. */
185			if ( sscanf( cp, "%[^ \t\n] %[^ \t\n]", file, url ) == 2 )
186			{
187			/* Check for wildcard match. */
188			star = strchr( file, '*' );
189			if ( star != (char*) 0 )
190			{
191			/* Check for leading match. */
192			if ( strncmp( file, script_name, star - file ) == 0 )
193			{
194			/* Got it; put together the full name. */
195			strcat( url, script_name + ( star - file ) );
196			/* XXX Whack the script_name, too? */
197			moved( script_name, url );
198			exit( 0 );
199			}
200			}
201			/* Check for exact match. */
202			if ( strcmp( file, script_name ) == 0 )
203			{
204			/* Got it. */
205			moved( script_name, url );
206			exit( 0 );
207			}
208			}
209			}
210			}
211
212			/* No match found. */
213			not_found( script_name );
214			exit( 1 );
215			}