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 *
#	Content
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	}