/* $Id: htmlerror.c,v 1.2 2003-03-14 22:45:59 rjkaes Exp $ * * This file contains source code for the handling and display of * HTML error pages with variable substitution. * * 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, 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. */ #include "tinyproxy.h" #include "common.h" #include "buffer.h" #include "conns.h" #include "heap.h" #include "htmlerror.h" #include "network.h" #include "utils.h" /* * Add an error number -> filename mapping to the errorpages list. */ int add_new_errorpage(char *filepath, unsigned int errornum) { static int errorpage_count = 1; /* First, add space for another pointer to the errorpages array. */ config.errorpages = saferealloc(config.errorpages, sizeof(struct error_pages_s *) * (errorpage_count + 1)); if(!config.errorpages) return(-1); /* Allocate space for an actual structure */ config.errorpages[errorpage_count - 1] = safemalloc(sizeof(struct error_pages_s)); if(!config.errorpages[errorpage_count - 1]) return(-1); /* Set values for errorpage structure. */ config.errorpages[errorpage_count - 1]->errorpage_path = safestrdup(filepath); if(!config.errorpages[errorpage_count - 1]->errorpage_path) return(-1); config.errorpages[errorpage_count - 1]->errorpage_errnum = errornum; /* Set NULL to denote end of array */ config.errorpages[errorpage_count] = NULL; errorpage_count++; return(0); } /* * Get the file appropriate for a given error. */ char* get_html_file(int errornum) { int i; if(!config.errorpages) return(config.errorpage_undef); for(i = 0; config.errorpages[i]; i++) { if(config.errorpages[i]->errorpage_errnum == errornum) return(config.errorpages[i]->errorpage_path); } return(config.errorpage_undef); } /* * Look up the value for a variable. */ char* lookup_variable(struct conn_s *connptr, char *varname) { int i; for(i = 0; ierror_variable_count; i++) { if(!strcasecmp(connptr->error_variables[i]->error_key, varname)) return(connptr->error_variables[i]->error_val); } return(NULL); } #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. */ int add_error_variable(struct conn_s *connptr, char *key, char *val) { connptr->error_variable_count++; /* Add space for a new pointer to the error_variables structure. */ connptr->error_variables = saferealloc(connptr->error_variables, sizeof(struct error_variable_s *) * connptr->error_variable_count); if(!connptr->error_variables) return(-1); /* Allocate a new variable mapping structure. */ connptr->error_variables[connptr->error_variable_count - 1] = safemalloc(sizeof(struct error_variable_s)); if(!connptr->error_variables[connptr->error_variable_count - 1]) return(-1); /* Set values for variable mapping. */ connptr->error_variables[connptr->error_variable_count - 1]->error_key = safestrdup(key); connptr->error_variables[connptr->error_variable_count - 1]->error_val = safestrdup(val); if((!connptr->error_variables[connptr->error_variable_count - 1]->error_key) || (!connptr->error_variables[connptr->error_variable_count - 1]->error_val)) return(-1); return(0); } #define ADD_VAR_RET(x, y) if(y) { if(add_error_variable(connptr, x, y) == -1) return(-1); } /* * Set some standard variables used by all HTML pages */ int add_standard_vars(struct conn_s *connptr) { char timebuf[30]; time_t global_time = time(NULL); strftime(timebuf, sizeof(timebuf), "%a, %d %b %Y %H:%M:%S GMT", gmtime(&global_time)); ADD_VAR_RET("request", connptr->request_line); ADD_VAR_RET("cause", connptr->error_string); 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("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) return(-1); } connptr->error_number = number; connptr->error_string = safestrdup(message); return(add_standard_vars(connptr)); }