--- /dev/null
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * 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"
+#include "http_protocol.h" /* ap_hook_insert_error_filter */
+
+/* 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;
+
+/*
+ * magic cmd->info values
+ */
+static char hdr_in = '0'; /* RequestHeader */
+static char hdr_out = '1'; /* Header onsuccess */
+static char hdr_err = '2'; /* Header always */
+
+/*
+ * 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;
+ apr_array_header_t *fixup_err;
+} 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=%" APR_TIME_T_FMT,
+ (apr_time_now() - r->request_time));
+}
+static const char *header_request_time(request_rec *r, char *a)
+{
+ return apr_psprintf(r->pool, "t=%" APR_TIME_T_FMT, 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, char *dummy)
+{
+ headers_conf *conf = apr_palloc(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));
+ conf->fixup_err = apr_array_make(p, 2, sizeof(header_entry));
+
+ return conf;
+}
+
+static void *merge_headers_config(apr_pool_t *p, void *basev, void *overridesv)
+{
+ headers_conf *newconf = apr_palloc(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);
+ newconf->fixup_err = apr_array_append(p, base->fixup_err, overrides->fixup_err);
+
+ 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(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;
+ apr_array_header_t *fixup = (cmd->info == &hdr_in)
+ ? dirconf->fixup_in : (cmd->info == &hdr_err)
+ ? dirconf->fixup_err
+ : dirconf->fixup_out;
+
+ new = (header_entry *) apr_array_push(fixup);
+
+ 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 (cmd->info == &hdr_in)
+ 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 (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 all (xxx)Header directives */
+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);
+ if (cmd->info == &hdr_out) {
+ if (!strcasecmp(action, "always")) {
+ cmd->info = &hdr_err;
+ action = ap_getword_conf(cmd->pool, &s);
+ }
+ else if (!strcasecmp(action, "onsuccess")) {
+ 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;
+
+ if (*s) {
+ return apr_pstrcat(cmd->pool, cmd->cmd->name,
+ " has too many arguments", NULL);
+ }
+
+ return header_inout_cmd(cmd, indirconf, action, hdr, val, envclause);
+}
+
+/*
+ * 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 ? 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, apr_table_t *headers,
+ apr_array_header_t *fixup)
+{
+ int i;
+
+ 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 *dirconf = ap_get_module_config(r->per_dir_config,
+ &headers_module);
+
+ if (dirconf->fixup_out->nelts || dirconf->fixup_err->nelts) {
+ ap_add_output_filter("FIXUP_HEADERS_OUT", NULL, r, r->connection);
+ }
+}
+
+static void ap_headers_insert_error_filter(request_rec *r)
+{
+ headers_conf *dirconf = ap_get_module_config(r->per_dir_config,
+ &headers_module);
+
+ if (dirconf->fixup_err->nelts) {
+ ap_add_output_filter("FIXUP_HEADERS_ERR", NULL, r, r->connection);
+ }
+}
+
+static apr_status_t ap_headers_output_filter(ap_filter_t *f,
+ apr_bucket_brigade *in)
+{
+ headers_conf *dirconf = ap_get_module_config(f->r->per_dir_config,
+ &headers_module);
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, f->r->server,
+ "headers: ap_headers_output_filter()");
+
+ /* do the fixup */
+ do_headers_fixup(f->r, f->r->err_headers_out, dirconf->fixup_err);
+ do_headers_fixup(f->r, f->r->headers_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_error_filter(ap_filter_t *f,
+ apr_bucket_brigade *in)
+{
+ headers_conf *dirconf = ap_get_module_config(f->r->per_dir_config,
+ &headers_module);
+
+ ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, f->r->server,
+ "headers: ap_headers_error_filter()");
+
+ /* do the fixup */
+ do_headers_fixup(f->r, f->r->err_headers_out, dirconf->fixup_err);
+
+ /* 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 *dirconf = ap_get_module_config(r->per_dir_config,
+ &headers_module);
+
+ /* do the fixup */
+ if (dirconf->fixup_in->nelts) {
+ do_headers_fixup(r, r->headers_in, dirconf->fixup_in);
+ }
+
+ return DECLINED;
+}
+
+static const command_rec headers_cmds[] =
+{
+ AP_INIT_RAW_ARGS("Header", header_cmd, &hdr_out, OR_FILEINFO,
+ "an optional condition, an action, header and value "
+ "followed by optional env clause"),
+ AP_INIT_RAW_ARGS("RequestHeader", header_cmd, &hdr_in, 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 int 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);
+
+ return OK;
+}
+
+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_insert_error_filter(ap_headers_insert_error_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,
+ NULL, AP_FTYPE_CONTENT_SET);
+ ap_register_output_filter("FIXUP_HEADERS_ERR", ap_headers_error_filter,
+ NULL, AP_FTYPE_CONTENT_SET);
+}
+
+module AP_MODULE_DECLARE_DATA headers_module =
+{
+ STANDARD20_MODULE_STUFF,
+ create_headers_config, /* dir config creater */
+ merge_headers_config, /* dir merger --- default is to override */
+ NULL, /* server config */
+ NULL, /* merge server configs */
+ headers_cmds, /* command apr_table_t */
+ register_hooks /* register hooks */
+};
Code Review / bottlenecks.git / blobdiff