| /* ==================================================================== |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2000-2001 The Apache Software Foundation. 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. |
| * |
| * 3. The end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Apache" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR |
| * ITS 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. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| * Portions of this software are based upon public domain software |
| * originally written at the National Center for Supercomputing Applications, |
| * University of Illinois, Urbana-Champaign. |
| */ |
| |
| /* |
| * mod_headers.c: Add/append/remove HTTP response headers |
| * Written by Paul Sutton, paul@ukweb.com, 1 Oct 1996 |
| * |
| * The Header directive can be used to add/replace/remove HTTP headers |
| * within the response message. The RequestHeader directive can be used |
| * to add/replace/remove HTTP headers before a request message is processed. |
| * Valid in both per-server and per-dir configurations. |
| * |
| * Syntax is: |
| * |
| * Header action header value |
| * RequestHeader action header value |
| * |
| * Where action is one of: |
| * set - set this header, replacing any old value |
| * add - add this header, possible resulting in two or more |
| * headers with the same name |
| * append - append this text onto any existing header of this same |
| * unset - remove this header |
| * |
| * Where action is unset, the third argument (value) should not be given. |
| * The header name can include the colon, or not. |
| * |
| * The Header and RequestHeader directives can only be used where allowed |
| * by the FileInfo override. |
| * |
| * When the request is processed, the header directives are processed in |
| * this order: firstly, the main server, then the virtual server handling |
| * this request (if any), then any <Directory> sections (working downwards |
| * from the root dir), then an <Location> sections (working down from |
| * shortest URL component), the any <File> sections. This order is |
| * important if any 'set' or 'unset' actions are used. For example, |
| * the following two directives have different effect if applied in |
| * the reverse order: |
| * |
| * Header append Author "John P. Doe" |
| * Header unset Author |
| * |
| * Examples: |
| * |
| * To set the "Author" header, use |
| * Header add Author "John P. Doe" |
| * |
| * To remove a header: |
| * Header unset Author |
| * |
| */ |
| |
| #include "apr.h" |
| #include "apr_lib.h" |
| #include "apr_strings.h" |
| #include "apr_buckets.h" |
| |
| #include "apr_hash.h" |
| #define APR_WANT_STRFUNC |
| #include "apr_want.h" |
| |
| #include "httpd.h" |
| #include "http_config.h" |
| #include "http_request.h" |
| #include "http_log.h" |
| #include "util_filter.h" |
| |
| /* format_tag_hash is initialized during pre-config */ |
| static apr_hash_t *format_tag_hash; |
| |
| typedef enum { |
| hdr_add = 'a', /* add header (could mean multiple hdrs) */ |
| hdr_set = 's', /* set (replace old value) */ |
| hdr_append = 'm', /* append (merge into any old value) */ |
| hdr_unset = 'u', /* unset header */ |
| hdr_echo = 'e' /* echo headers from request to response */ |
| } hdr_actions; |
| |
| typedef enum { |
| hdr_in = 0, /* RequestHeader */ |
| hdr_out = 1 /* Header */ |
| } hdr_inout; |
| |
| /* |
| * There is an array of struct format_tag per Header/RequestHeader |
| * config directive |
| */ |
| typedef struct { |
| const char* (*func)(request_rec *r,char *arg); |
| char *arg; |
| } format_tag; |
| |
| /* |
| * There is one "header_entry" per Header/RequestHeader config directive |
| */ |
| typedef struct { |
| hdr_actions action; |
| char *header; |
| apr_array_header_t *ta; /* Array of format_tag structs */ |
| regex_t *regex; |
| const char *condition_var; |
| } header_entry; |
| |
| /* echo_do is used for Header echo to iterate through the request headers*/ |
| typedef struct { |
| request_rec *r; |
| header_entry *hdr; |
| } echo_do; |
| |
| /* |
| * headers_conf is our per-module configuration. This is used as both |
| * a per-dir and per-server config |
| */ |
| typedef struct { |
| apr_array_header_t *fixup_in; |
| apr_array_header_t *fixup_out; |
| } headers_conf; |
| |
| module AP_MODULE_DECLARE_DATA headers_module; |
| |
| /* |
| * Tag formatting functions |
| */ |
| static const char *constant_item(request_rec *r, char *stuff) |
| { |
| return stuff; |
| } |
| static const char *header_request_duration(request_rec *r, char *a) |
| { |
| return apr_psprintf(r->pool, "D=%qd", (apr_time_now() - r->request_time)); |
| } |
| static const char *header_request_time(request_rec *r, char *a) |
| { |
| return apr_psprintf(r->pool, "t=%qd", r->request_time); |
| } |
| static const char *header_request_env_var(request_rec *r, char *a) |
| { |
| const char *s = apr_table_get(r->subprocess_env,a); |
| |
| if (s) |
| return s; |
| else |
| return "(null)"; |
| } |
| /* |
| * Config routines |
| */ |
| static void *create_headers_config(apr_pool_t *p, server_rec *s) |
| { |
| headers_conf *conf = apr_pcalloc(p, sizeof(*conf)); |
| |
| conf->fixup_in = apr_array_make(p, 2, sizeof(header_entry)); |
| conf->fixup_out = apr_array_make(p, 2, sizeof(header_entry)); |
| |
| return conf; |
| } |
| |
| static void *create_headers_dir_config(apr_pool_t *p, char *d) |
| { |
| return create_headers_config(p, NULL); |
| } |
| |
| static void *merge_headers_config(apr_pool_t *p, void *basev, void *overridesv) |
| { |
| headers_conf *newconf = apr_pcalloc(p, sizeof(*newconf)); |
| headers_conf *base = basev; |
| headers_conf *overrides = overridesv; |
| |
| newconf->fixup_in = apr_array_append(p, base->fixup_in, overrides->fixup_in); |
| newconf->fixup_out = apr_array_append(p, base->fixup_out, overrides->fixup_out); |
| |
| return newconf; |
| } |
| |
| static char *parse_misc_string(apr_pool_t *p, format_tag *tag, const char **sa) |
| { |
| const char *s; |
| char *d; |
| |
| tag->func = constant_item; |
| |
| s = *sa; |
| while (*s && *s != '%') { |
| s++; |
| } |
| /* |
| * This might allocate a few chars extra if there's a backslash |
| * escape in the format string. |
| */ |
| tag->arg = apr_palloc(p, s - *sa + 1); |
| |
| d = tag->arg; |
| s = *sa; |
| while (*s && *s != '%') { |
| if (*s != '\\') { |
| *d++ = *s++; |
| } |
| else { |
| s++; |
| switch (*s) { |
| case '\\': |
| *d++ = '\\'; |
| s++; |
| break; |
| case 'r': |
| *d++ = '\r'; |
| s++; |
| break; |
| case 'n': |
| *d++ = '\n'; |
| s++; |
| break; |
| case 't': |
| *d++ = '\t'; |
| s++; |
| break; |
| default: |
| /* copy verbatim */ |
| *d++ = '\\'; |
| /* |
| * Allow the loop to deal with this *s in the normal |
| * fashion so that it handles end of string etc. |
| * properly. |
| */ |
| break; |
| } |
| } |
| } |
| *d = '\0'; |
| |
| *sa = s; |
| return NULL; |
| } |
| |
| static char *parse_format_tag(apr_pool_t *p, format_tag *tag, const char **sa) |
| { |
| const char *s = *sa; |
| const char * (*tag_handler)(request_rec *,char *); |
| |
| /* Handle string literal/conditionals */ |
| if (*s != '%') { |
| return parse_misc_string(p, tag, sa); |
| } |
| s++; /* skip the % */ |
| tag->arg = '\0'; |
| /* grab the argument if there is one */ |
| if (*s == '{') { |
| ++s; |
| tag->arg = ap_getword(p,&s,'}'); |
| } |
| |
| tag_handler = (const char * (*)(request_rec *,char *))apr_hash_get(format_tag_hash, s++, 1); |
| |
| if (!tag_handler) { |
| char dummy[2]; |
| dummy[0] = s[-1]; |
| dummy[1] = '\0'; |
| return apr_pstrcat(p, "Unrecognized Header or RequestHeader directive %", |
| dummy, NULL); |
| } |
| tag->func = tag_handler; |
| |
| *sa = s; |
| return NULL; |
| } |
| |
| /* |
| * A format string consists of white space, text and optional format |
| * tags in any order. E.g., |
| * |
| * Header add MyHeader "Free form text %D %t more text" |
| * |
| * Decompose the format string into its tags. Each tag (struct format_tag) |
| * contains a pointer to the function used to format the tag. Then save each |
| * tag in the tag array anchored in the header_entry. |
| */ |
| static char *parse_format_string(apr_pool_t *p, header_entry *hdr, const char *s) |
| { |
| char *res; |
| |
| /* No string to parse with unset and copy commands */ |
| if (hdr->action == hdr_unset || |
| hdr->action == hdr_echo) { |
| return NULL; |
| } |
| |
| hdr->ta = apr_array_make(p, 10, sizeof(format_tag)); |
| |
| while (*s) { |
| if ((res = parse_format_tag(p, (format_tag *) apr_array_push(hdr->ta), &s))) { |
| return res; |
| } |
| } |
| return NULL; |
| } |
| |
| /* handle RequestHeader and Header directive */ |
| static const char *header_inout_cmd(hdr_inout inout, cmd_parms *cmd, void *indirconf, |
| const char *action, const char *inhdr, |
| const char *value, const char* envclause) |
| { |
| headers_conf *dirconf = indirconf; |
| const char *condition_var = NULL; |
| char *colon; |
| char *hdr = apr_pstrdup(cmd->pool, inhdr); |
| header_entry *new; |
| server_rec *s = cmd->server; |
| headers_conf *serverconf = ap_get_module_config(s->module_config, |
| &headers_module); |
| |
| if (cmd->path) { |
| new = (header_entry *) apr_array_push((hdr_in == inout) ? dirconf->fixup_in : dirconf->fixup_out); |
| } |
| else { |
| new = (header_entry *) apr_array_push((hdr_in == inout) ? serverconf->fixup_in : serverconf->fixup_out); |
| } |
| |
| if (!strcasecmp(action, "set")) |
| new->action = hdr_set; |
| else if (!strcasecmp(action, "add")) |
| new->action = hdr_add; |
| else if (!strcasecmp(action, "append")) |
| new->action = hdr_append; |
| else if (!strcasecmp(action, "unset")) |
| new->action = hdr_unset; |
| else if (!strcasecmp(action, "echo")) |
| new->action = hdr_echo; |
| else |
| return "first argument must be add, set, append, unset or echo."; |
| |
| if (new->action == hdr_unset) { |
| if (value) |
| return "header unset takes two arguments"; |
| } |
| else if (new->action == hdr_echo) { |
| regex_t *regex; |
| if (value) |
| return "Header echo takes two arguments"; |
| else if (inout != hdr_out) |
| return "Header echo only valid on Header directive"; |
| else { |
| regex = ap_pregcomp(cmd->pool, hdr, REG_EXTENDED | REG_NOSUB); |
| if (regex == NULL) { |
| return "Header echo regex could not be compiled"; |
| } |
| } |
| new->regex = regex; |
| } |
| else if (!value) |
| return "header requires three arguments"; |
| |
| /* Handle the envclause on Header */ |
| if (envclause != NULL) { |
| if (inout != hdr_out) { |
| return "error: envclause (env=...) only valid on Header directive"; |
| } |
| if (strncasecmp(envclause, "env=", 4) != 0) { |
| return "error: envclause should be in the form env=envar"; |
| } |
| if ((envclause[4] == '\0') |
| || ((envclause[4] == '!') && (envclause[5] == '\0'))) { |
| return "error: missing environment variable name. envclause should be in the form env=envar "; |
| } |
| condition_var = apr_pstrdup(cmd->pool, &envclause[4]); |
| } |
| |
| if ((colon = strchr(hdr, ':'))) |
| *colon = '\0'; |
| |
| new->header = hdr; |
| new->condition_var = condition_var; |
| |
| return parse_format_string(cmd->pool, new, value); |
| } |
| |
| /* Handle Header directive */ |
| static const char *header_cmd(cmd_parms *cmd, void *indirconf, |
| const char *args) |
| { |
| const char *s; |
| const char *action; |
| const char *hdr; |
| const char *val; |
| const char *envclause; |
| |
| s = apr_pstrdup(cmd->pool, args); |
| action = ap_getword_conf(cmd->pool, &s); |
| hdr = ap_getword_conf(cmd->pool, &s); |
| val = *s ? ap_getword_conf(cmd->pool, &s) : NULL; |
| envclause = *s ? ap_getword_conf(cmd->pool, &s) : NULL; |
| |
| return header_inout_cmd(hdr_out, cmd, indirconf, action, hdr, val, envclause); |
| } |
| |
| /* handle RequestHeader directive */ |
| static const char *request_header_cmd(cmd_parms *cmd, void *indirconf, |
| const char *action, const char *inhdr, |
| const char *value) |
| { |
| return header_inout_cmd(hdr_in, cmd, indirconf, action, inhdr, value, NULL); |
| } |
| |
| /* |
| * Process the tags in the format string. Tags may be format specifiers |
| * (%D, %t, etc.), whitespace or text strings. For each tag, run the handler |
| * (formatter) specific to the tag. Handlers return text strings. |
| * Concatenate the return from each handler into one string that is |
| * returned from this call. |
| */ |
| static char* process_tags(header_entry *hdr, request_rec *r) |
| { |
| int i; |
| const char *s; |
| char *str = NULL; |
| |
| format_tag *tag = (format_tag*) hdr->ta->elts; |
| |
| for (i = 0; i < hdr->ta->nelts; i++) { |
| s = tag[i].func(r, tag[i].arg); |
| if (str == NULL) |
| str = apr_pstrdup(r->pool, s); |
| else |
| str = apr_pstrcat(r->pool, str, s, NULL); |
| } |
| return str; |
| } |
| |
| static int echo_header(echo_do *v, const char *key, const char *val) |
| { |
| /* If the input header (key) matches the regex, echo it intact to |
| * r->headers_out. |
| */ |
| if (!ap_regexec(v->hdr->regex, key, 0, NULL, 0)) { |
| apr_table_add(v->r->headers_out, key, val); |
| } |
| |
| return 1; |
| } |
| |
| static void do_headers_fixup(request_rec *r, hdr_inout inout, |
| apr_array_header_t *fixup) |
| { |
| int i; |
| apr_table_t *headers = (hdr_in == inout) ? r->headers_in : r->headers_out; |
| |
| for (i = 0; i < fixup->nelts; ++i) { |
| header_entry *hdr = &((header_entry *) (fixup->elts))[i]; |
| |
| /* Have any conditional envar-controlled Header processing to do? */ |
| if (hdr->condition_var) { |
| const char *envar = hdr->condition_var; |
| if (*envar != '!') { |
| if (apr_table_get(r->subprocess_env, envar) == NULL) |
| continue; |
| } |
| else { |
| if (apr_table_get(r->subprocess_env, &envar[1]) != NULL) |
| continue; |
| } |
| } |
| |
| switch (hdr->action) { |
| case hdr_add: |
| apr_table_addn(headers, hdr->header, process_tags(hdr, r)); |
| break; |
| case hdr_append: |
| apr_table_mergen(headers, hdr->header, process_tags(hdr, r)); |
| break; |
| case hdr_set: |
| apr_table_setn(headers, hdr->header, process_tags(hdr, r)); |
| break; |
| case hdr_unset: |
| apr_table_unset(headers, hdr->header); |
| break; |
| case hdr_echo: |
| { |
| echo_do v; |
| v.r = r; |
| v.hdr = hdr; |
| apr_table_do((int (*) (void *, const char *, const char *)) |
| echo_header, (void *) &v, r->headers_in, NULL); |
| break; |
| } |
| } |
| } |
| } |
| |
| static void ap_headers_insert_output_filter(request_rec *r) |
| { |
| headers_conf *serverconf = ap_get_module_config(r->server->module_config, |
| &headers_module); |
| headers_conf *dirconf = ap_get_module_config(r->per_dir_config, |
| &headers_module); |
| |
| if (serverconf->fixup_out->nelts || dirconf->fixup_out->nelts) { |
| ap_add_output_filter("FIXUP_HEADERS_OUT", NULL, r, r->connection); |
| } |
| } |
| |
| static apr_status_t ap_headers_output_filter(ap_filter_t *f, |
| apr_bucket_brigade *in) |
| { |
| headers_conf *serverconf = ap_get_module_config(f->r->server->module_config, |
| &headers_module); |
| headers_conf *dirconf = ap_get_module_config(f->r->per_dir_config, |
| &headers_module); |
| |
| ap_log_error(APLOG_MARK, APLOG_DEBUG|APLOG_NOERRNO, 0, f->r->server, |
| "headers: ap_headers_output_filter()"); |
| |
| /* do the fixup */ |
| do_headers_fixup(f->r, hdr_out, serverconf->fixup_out); |
| do_headers_fixup(f->r, hdr_out, dirconf->fixup_out); |
| |
| /* remove ourselves from the filter chain */ |
| ap_remove_output_filter(f); |
| |
| /* send the data up the stack */ |
| return ap_pass_brigade(f->next,in); |
| } |
| |
| static apr_status_t ap_headers_fixup(request_rec *r) |
| { |
| headers_conf *serverconf = ap_get_module_config(r->server->module_config, |
| &headers_module); |
| headers_conf *dirconf = ap_get_module_config(r->per_dir_config, |
| &headers_module); |
| |
| /* do the fixup */ |
| if (serverconf->fixup_in->nelts || dirconf->fixup_in->nelts) { |
| do_headers_fixup(r, hdr_in, serverconf->fixup_in); |
| do_headers_fixup(r, hdr_in, dirconf->fixup_in); |
| } |
| |
| return DECLINED; |
| } |
| |
| static const command_rec headers_cmds[] = |
| { |
| AP_INIT_RAW_ARGS("Header", header_cmd, NULL, OR_FILEINFO, |
| "an action, header and value followed by optional env clause"), |
| AP_INIT_TAKE23("RequestHeader", request_header_cmd, NULL, OR_FILEINFO, |
| "an action, header and value"), |
| {NULL} |
| }; |
| |
| static void register_format_tag_handler(apr_pool_t *p, char *tag, void *tag_handler, int def) |
| { |
| const void *h = apr_palloc(p, sizeof(h)); |
| h = tag_handler; |
| apr_hash_set(format_tag_hash, tag, 1, h); |
| } |
| static void header_pre_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp) |
| { |
| format_tag_hash = apr_hash_make(p); |
| register_format_tag_handler(p, "D", (void*) header_request_duration, 0); |
| register_format_tag_handler(p, "t", (void*) header_request_time, 0); |
| register_format_tag_handler(p, "e", (void*) header_request_env_var, 0); |
| } |
| |
| static void register_hooks(apr_pool_t *p) |
| { |
| ap_hook_pre_config(header_pre_config,NULL,NULL,APR_HOOK_MIDDLE); |
| ap_hook_insert_filter(ap_headers_insert_output_filter, NULL, NULL, APR_HOOK_LAST); |
| ap_hook_fixups(ap_headers_fixup, NULL, NULL, APR_HOOK_LAST); |
| ap_register_output_filter("FIXUP_HEADERS_OUT", ap_headers_output_filter, AP_FTYPE_HTTP_HEADER); |
| } |
| |
| module AP_MODULE_DECLARE_DATA headers_module = |
| { |
| STANDARD20_MODULE_STUFF, |
| create_headers_dir_config, /* dir config creater */ |
| merge_headers_config, /* dir merger --- default is to override */ |
| create_headers_config, /* server config */ |
| merge_headers_config, /* merge server configs */ |
| headers_cmds, /* command apr_table_t */ |
| register_hooks /* register hooks */ |
| }; |
