/* tinyproxy - A fast light-weight HTTP proxy * Copyright (C) 2003 Steven Young * * 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 2 of the License, 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., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ /* This file contains source code for the handling and display of * HTML error pages with variable substitution. */ #include "tinyproxy.h" #include "common.h" #include "buffer.h" #include "conns.h" #include "heap.h" #include "html-error.h" #include "network.h" #include "utils.h" /* * Add an error number -> filename mapping to the errorpages list. */ #define ERRORNUM_BUFSIZE 8 /* this is more than required */ #define ERRPAGES_BUCKETCOUNT 16 int add_new_errorpage(char *filepath, unsigned int errornum) { char errornbuf[ERRORNUM_BUFSIZE]; config.errorpages = hashmap_create(ERRPAGES_BUCKETCOUNT); if (!config.errorpages) return (-1); snprintf(errornbuf, ERRORNUM_BUFSIZE, "%u", errornum); if (hashmap_insert(config.errorpages, errornbuf, filepath, strlen(filepath) + 1) < 0) return (-1); return (0); } /* * Get the file appropriate for a given error. */ static char * get_html_file(unsigned int errornum) { hashmap_iter result_iter; char errornbuf[ERRORNUM_BUFSIZE]; char *key; static char *val; assert(errornum >= 100 && errornum < 1000); if (!config.errorpages) return (config.errorpage_undef); snprintf(errornbuf, ERRORNUM_BUFSIZE, "%u", errornum); result_iter = hashmap_find(config.errorpages, errornbuf); if (hashmap_is_end(config.errorpages, result_iter)) return (config.errorpage_undef); if (hashmap_return_entry(config.errorpages, result_iter, &key, (void **)&val) < 0) return (config.errorpage_undef); return (val); } /* * Look up the value for a variable. */ static char * lookup_variable(struct conn_s *connptr, char *varname) { hashmap_iter result_iter; char *key; static char *data; result_iter = hashmap_find(connptr->error_variables, varname); if (hashmap_is_end(connptr->error_variables, result_iter)) return (NULL); if (hashmap_return_entry(connptr->error_variables, result_iter, &key, (void **)&data) < 0) return (NULL); return (data); } #define HTML_BUFSIZE 4096 /* * Send an already-opened file to the client with variable substitution. */ int send_html_file(FILE * infile, struct conn_s *connptr) { char inbuf[HTML_BUFSIZE], *varstart = NULL, *p; char *varval; int in_variable = 0, writeret; while (fgets(inbuf, HTML_BUFSIZE, infile) != NULL) { for (p = inbuf; *p; p++) { switch (*p) { case '}': if (in_variable) { *p = '\0'; if (! (varval = lookup_variable(connptr, varstart))) varval = "(unknown)"; writeret = write_message(connptr->client_fd, "%s", varval); if (writeret) return (writeret); in_variable = 0; } else { writeret = write_message(connptr->client_fd, "%c", *p); if (writeret) return (writeret); } break; case '{': /* a {{ will print a single {. If we are NOT * already in a { variable, then proceed with * setup. If we ARE already in a { variable, * this code will fallthrough to the code that * just dumps a character to the client fd. */ if (!in_variable) { varstart = p + 1; in_variable++; } else in_variable = 0; default: if (!in_variable) { writeret = write_message(connptr->client_fd, "%c", *p); if (writeret) return (writeret); } } } in_variable = 0; } return (0); } int send_http_headers(struct conn_s *connptr, int code, char *message) { char *headers = "HTTP/1.0 %d %s\r\n" "Server: %s/%s\r\n" "Content-Type: text/html\r\n" "Connection: close\r\n" "\r\n"; return (write_message(connptr->client_fd, headers, code, message, PACKAGE, VERSION)); } /* * Display an error to the client. */ int send_http_error_message(struct conn_s *connptr) { char *error_file; FILE *infile; int ret; char *fallback_error = "%s" "
%s %s
" "The page you requested was unavailable. The error code is listed " "below. In addition, the HTML file which has been configured as the " "page to be displayed when an error of this type was unavailable, " "with the error code %d (%s). Please contact your administrator." "
%s
" "" "\r\n"; send_http_headers(connptr, connptr->error_number, connptr->error_string); error_file = get_html_file(connptr->error_number); if (!(infile = fopen(error_file, "r"))) return (write_message(connptr->client_fd, fallback_error, connptr->error_string, PACKAGE, VERSION, errno, strerror(errno), connptr->error_string)); ret = send_html_file(infile, connptr); fclose(infile); return (ret); } /* * Add a key -> value mapping for HTML file substitution. */ #define ERRVAR_BUCKETCOUNT 16 int add_error_variable(struct conn_s *connptr, char *key, char *val) { if (!connptr->error_variables) if (! (connptr->error_variables = hashmap_create(ERRVAR_BUCKETCOUNT))) return (-1); return hashmap_insert(connptr->error_variables, key, val, strlen(val) + 1); } #define ADD_VAR_RET(x, y) \ do { \ if (add_error_variable(connptr, x, y) < 0) \ return -1; \ } while (0) /* * Set some standard variables used by all HTML pages */ int add_standard_vars(struct conn_s *connptr) { char errnobuf[16]; char timebuf[30]; time_t global_time; snprintf(errnobuf, sizeof errnobuf, "%d", connptr->error_number); ADD_VAR_RET("errno", errnobuf); ADD_VAR_RET("cause", connptr->error_string); ADD_VAR_RET("request", connptr->request_line); ADD_VAR_RET("clientip", connptr->client_ip_addr); ADD_VAR_RET("clienthost", connptr->client_string_addr); ADD_VAR_RET("version", VERSION); ADD_VAR_RET("package", PACKAGE); ADD_VAR_RET("website", "http://tinyproxy.banu.com/"); global_time = time(NULL); strftime(timebuf, sizeof(timebuf), "%a, %d %b %Y %H:%M:%S GMT", gmtime(&global_time)); ADD_VAR_RET("date", timebuf); return (0); } /* * Add the error information to the conn structure. */ int indicate_http_error(struct conn_s *connptr, int number, char *message, ...) { va_list ap; char *key, *val; va_start(ap, message); while ((key = va_arg(ap, char *))) { val = va_arg(ap, char *); if (add_error_variable(connptr, key, val) == -1) { va_end(ap); return (-1); } } connptr->error_number = number; connptr->error_string = safestrdup(message); va_end(ap); return (add_standard_vars(connptr)); }