/**************************************************************************** * apps/netutils/thttpd/cgi-src/redirect.c * Simple redirection CGI program * * Copyright (C) 2009, 2015 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Derived from the file of the same name in the original THTTPD package: * * Copyright © 1995 by Jef Poskanzer . * 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. */ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #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"; printf("Status: %s\n" "Content-type: text/html\n" "\n" "%s\n" "

%s

\n" "Something unusual went wrong during a redirection request:\n" "
\n" "%s\n" "
\n" "\n", title, title, title, reason); } static void not_found(char *script_name) { char *title = "404 Not Found"; printf("Status: %s\n" "Content-type: text/html\n" "\n" "%s\n" "

%s

\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" "\n", title, title, title, script_name); } static void moved(char *script_name, char *url) { char *title = "Moved"; printf("Location: %s\n" "Content-type: text/html\n" "\n" "%s\n" "

%s

\n" "The requested filename, %s, has moved to a new URL:\n" "%s.\n" "\n", url, title, title, script_name, url, url); } /**************************************************************************** * Public Functions ****************************************************************************/ #ifdef CONFIG_THTTPD_BINFS int redirect_main(int argc, char *argv[]) #else int main(int argc, char *argv[]) #endif { char *script_name; char *path_info; char *cp = 0; FILE *fp; char *star; int errcode = 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; } 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."); errcode = 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); errcode = 4; success_out: fclose(fp); errout_with_cp: if (cp) { free(cp); } return errcode; }