util_expr_eval.c revision c1ea0100af157a0d4e4a3de323f32dbfac4e5b6e
356N/A/* Licensed to the Apache Software Foundation (ASF) under one or more
356N/A * contributor license agreements. See the NOTICE file distributed with
356N/A * this work for additional information regarding copyright ownership.
356N/A * The ASF licenses this file to You under the Apache License, Version 2.0
356N/A * (the "License"); you may not use this file except in compliance with
356N/A * the License. You may obtain a copy of the License at
356N/A *
356N/A * http://www.apache.org/licenses/LICENSE-2.0
356N/A *
356N/A * Unless required by applicable law or agreed to in writing, software
356N/A * distributed under the License is distributed on an "AS IS" BASIS,
356N/A * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
356N/A * See the License for the specific language governing permissions and
356N/A * limitations under the License.
356N/A */
356N/A
356N/A/* _ _
356N/A * ap_expr_eval.c, based on ssl_expr_eval.c from mod_ssl
356N/A */
356N/A
2516N/A#include "httpd.h"
356N/A#include "http_log.h"
2516N/A#include "http_core.h"
356N/A#include "http_protocol.h"
356N/A#include "http_request.h"
356N/A#include "ap_provider.h"
2516N/A#include "util_expr_private.h"
2516N/A
2516N/A#include "apr_lib.h"
356N/A#include "apr_fnmatch.h"
356N/A
2516N/AAPLOG_USE_MODULE(core);
844N/A
2516N/AAPR_HOOK_STRUCT(
2516N/A APR_HOOK_LINK(expr_lookup)
2516N/A)
2516N/A
3661N/AAP_IMPLEMENT_HOOK_RUN_FIRST(int, expr_lookup, (ap_expr_lookup_parms *parms),
3661N/A (parms), DECLINED)
356N/A
2516N/A#define LOG_MARK(info) __FILE__, __LINE__, (info)->module_index
2516N/A
2516N/Astatic const char *ap_expr_eval_string_func(ap_expr_eval_ctx_t *ctx,
356N/A const ap_expr_t *info,
356N/A const ap_expr_t *args);
356N/Astatic const char *ap_expr_eval_re_backref(ap_expr_eval_ctx_t *ctx, int n);
356N/Astatic const char *ap_expr_eval_var(ap_expr_eval_ctx_t *ctx,
356N/A const ap_expr_var_func_t *func,
792N/A const void *data);
792N/A
2516N/A/* define AP_EXPR_DEBUG to log the parse tree when parsing an expression */
2516N/A#ifdef AP_EXPR_DEBUG
2516N/Astatic void expr_dump_tree(const ap_expr_t *e, const server_rec *s,
2516N/A int loglevel, int indent);
2516N/A#endif
356N/A
356N/Astatic const char *ap_expr_eval_word(ap_expr_eval_ctx_t *ctx,
356N/A const ap_expr_t *node)
356N/A{
356N/A const char *result = "";
356N/A switch (node->node_op) {
356N/A case op_Digit:
356N/A case op_String:
356N/A result = node->node_arg1;
356N/A break;
case op_Var:
result = ap_expr_eval_var(ctx, node->node_arg1, node->node_arg2);
break;
case op_Concat: {
const char *s1 = ap_expr_eval_word(ctx, node->node_arg1);
const char *s2 = ap_expr_eval_word(ctx, node->node_arg2);
if (!*s1)
result = s2;
else if (!*s2)
result = s1;
else
result = apr_pstrcat(ctx->p, s1, s2, NULL);
break;
}
case op_StringFuncCall: {
const ap_expr_t *info = node->node_arg1;
const ap_expr_t *args = node->node_arg2;
result = ap_expr_eval_string_func(ctx, info, args);
break;
}
case op_RegexBackref: {
const int *np = node->node_arg1;
result = ap_expr_eval_re_backref(ctx, *np);
break;
}
default:
*ctx->err = "Internal evaluation error: Unknown word expression node";
break;
}
if (!result)
result = "";
return result;
}
static const char *ap_expr_eval_var(ap_expr_eval_ctx_t *ctx,
const ap_expr_var_func_t *func,
const void *data)
{
AP_DEBUG_ASSERT(func != NULL);
AP_DEBUG_ASSERT(data != NULL);
return (*func)(ctx, data);
}
static const char *ap_expr_eval_re_backref(ap_expr_eval_ctx_t *ctx, int n)
{
int len;
if (!ctx->re_pmatch || !ctx->re_source || *ctx->re_source == '\0' ||
ctx->re_nmatch < n + 1)
return "";
len = ctx->re_pmatch[n].rm_eo - ctx->re_pmatch[n].rm_so;
if (len == 0)
return "";
return apr_pstrndup(ctx->p, *ctx->re_source + ctx->re_pmatch[n].rm_so, len);
}
static const char *ap_expr_eval_string_func(ap_expr_eval_ctx_t *ctx,
const ap_expr_t *info,
const ap_expr_t *arg)
{
ap_expr_string_func_t *func = (ap_expr_string_func_t *)info->node_arg1;
const void *data = info->node_arg2;
AP_DEBUG_ASSERT(info->node_op == op_StringFuncInfo);
AP_DEBUG_ASSERT(func != NULL);
AP_DEBUG_ASSERT(data != NULL);
return (*func)(ctx, data, ap_expr_eval_word(ctx, arg));
}
static int intstrcmp(const char *s1, const char *s2)
{
apr_int64_t i1 = apr_atoi64(s1);
apr_int64_t i2 = apr_atoi64(s2);
if (i1 < i2)
return -1;
else if (i1 == i2)
return 0;
else
return 1;
}
static int ap_expr_eval_comp(ap_expr_eval_ctx_t *ctx, const ap_expr_t *node)
{
const ap_expr_t *e1 = node->node_arg1;
const ap_expr_t *e2 = node->node_arg2;
switch (node->node_op) {
case op_EQ:
return (intstrcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) == 0);
case op_NE:
return (intstrcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) != 0);
case op_LT:
return (intstrcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) < 0);
case op_LE:
return (intstrcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) <= 0);
case op_GT:
return (intstrcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) > 0);
case op_GE:
return (intstrcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) >= 0);
case op_STR_EQ:
return (strcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) == 0);
case op_STR_NE:
return (strcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) != 0);
case op_STR_LT:
return (strcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) < 0);
case op_STR_LE:
return (strcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) <= 0);
case op_STR_GT:
return (strcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) > 0);
case op_STR_GE:
return (strcmp(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) >= 0);
case op_IN: {
const char *needle = ap_expr_eval_word(ctx, e1);
if (e2->node_op == op_ListElement) {
do {
const ap_expr_t *val = e2->node_arg1;
AP_DEBUG_ASSERT(e2->node_op == op_ListElement);
if (strcmp(needle, ap_expr_eval_word(ctx, val)) == 0) {
return 1;
break;
}
e2 = e2->node_arg2;
} while (e2 != NULL);
}
else if (e2->node_op == op_ListFuncCall) {
const ap_expr_t *info = e2->node_arg1;
const ap_expr_t *arg = e2->node_arg2;
ap_expr_list_func_t *func = (ap_expr_list_func_t *)info->node_arg1;
apr_array_header_t *haystack;
int i = 0;
AP_DEBUG_ASSERT(func != NULL);
AP_DEBUG_ASSERT(info->node_op == op_ListFuncInfo);
haystack = (*func)(ctx, info->node_arg2, ap_expr_eval_word(ctx, arg));
if (haystack == NULL)
return 0;
for (; i < haystack->nelts; i++) {
if (strcmp(needle, APR_ARRAY_IDX(haystack,i,char *)) == 0)
return 1;
}
}
return 0;
}
case op_REG:
case op_NRE: {
const char *word = ap_expr_eval_word(ctx, e1);
const ap_regex_t *regex = e2->node_arg1;
int result;
/*
* $0 ... $9 may contain stuff the user wants to keep. Therefore
* we only set them if there are capturing parens in the regex.
*/
if (regex->re_nsub > 0) {
result = (0 == ap_regexec(regex, word, ctx->re_nmatch,
ctx->re_pmatch, 0));
*ctx->re_source = result ? word : NULL;
}
else {
result = (0 == ap_regexec(regex, word, 0, NULL, 0));
}
if (node->node_op == op_REG)
return result;
else
return !result;
}
default:
*ctx->err = "Internal evaluation error: Unknown comp expression node";
return -1;
}
}
/* combined string/int comparison for compatibility with ssl_expr */
static int strcmplex(const char *str1, const char *str2)
{
int i, n1, n2;
if (str1 == NULL)
return -1;
if (str2 == NULL)
return +1;
n1 = strlen(str1);
n2 = strlen(str2);
if (n1 > n2)
return 1;
if (n1 < n2)
return -1;
for (i = 0; i < n1; i++) {
if (str1[i] > str2[i])
return 1;
if (str1[i] < str2[i])
return -1;
}
return 0;
}
static int ssl_expr_eval_comp(ap_expr_eval_ctx_t *ctx, const ap_expr_t *node)
{
const ap_expr_t *e1 = node->node_arg1;
const ap_expr_t *e2 = node->node_arg2;
switch (node->node_op) {
case op_EQ:
case op_STR_EQ:
return (strcmplex(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) == 0);
case op_NE:
case op_STR_NE:
return (strcmplex(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) != 0);
case op_LT:
case op_STR_LT:
return (strcmplex(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) < 0);
case op_LE:
case op_STR_LE:
return (strcmplex(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) <= 0);
case op_GT:
case op_STR_GT:
return (strcmplex(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) > 0);
case op_GE:
case op_STR_GE:
return (strcmplex(ap_expr_eval_word(ctx, e1), ap_expr_eval_word(ctx, e2)) >= 0);
default:
return ap_expr_eval_comp(ctx, node);
}
}
AP_DECLARE_NONSTD(int) ap_expr_lookup_default(ap_expr_lookup_parms *parms)
{
return ap_run_expr_lookup(parms);
}
AP_DECLARE(const char *) ap_expr_parse(apr_pool_t *pool, apr_pool_t *ptemp,
ap_expr_info_t *info, const char *expr,
ap_expr_lookup_fn_t *lookup_fn)
{
ap_expr_parse_ctx_t ctx;
int rc;
ctx.pool = pool;
ctx.ptemp = ptemp;
ctx.inputbuf = expr;
ctx.inputlen = strlen(expr);
ctx.inputptr = ctx.inputbuf;
ctx.expr = NULL;
ctx.error = NULL; /* generic bison error message (XXX: usually not very useful, should be axed) */
ctx.error2 = NULL; /* additional error message */
ctx.flags = info->flags;
ctx.scan_del = '\0';
ctx.scan_buf[0] = '\0';
ctx.scan_ptr = ctx.scan_buf;
ctx.lookup_fn = lookup_fn ? lookup_fn : ap_expr_lookup_default;
/*
* Be sure to avoid overflows in the scanner. In practice the input length
* will be limited by the config file parser, anyway.
* XXX: The scanner really should do proper buffer overflow checks
*/
if (ctx.inputlen >= MAX_STRING_LEN)
return "Expression too long";
ap_expr_yylex_init(&ctx.scanner);
ap_expr_yyset_extra(&ctx, ctx.scanner);
rc = ap_expr_yyparse(&ctx);
ap_expr_yylex_destroy(ctx.scanner);
if (ctx.error) {
if (ctx.error2)
return apr_psprintf(pool, "%s: %s", ctx.error, ctx.error2);
else
return ctx.error;
}
else if (ctx.error2) {
return ctx.error2;
}
if (rc) /* XXX can this happen? */
return "syntax error";
#ifdef AP_EXPR_DEBUG
if (ctx.expr)
expr_dump_tree(ctx.expr, NULL, APLOG_NOTICE, 2);
#endif
info->root_node = ctx.expr;
return NULL;
}
AP_DECLARE(ap_expr_info_t*) ap_expr_parse_cmd(const cmd_parms *cmd,
const char *expr,
const char **err,
ap_expr_lookup_fn_t *lookup_fn)
{
ap_expr_info_t *info = apr_pcalloc(cmd->pool, sizeof(ap_expr_info_t));
info->filename = cmd->directive->filename;
info->line_number = cmd->directive->line_num;
*err = ap_expr_parse(cmd->pool, cmd->temp_pool, info, expr, lookup_fn);
if (*err)
return NULL;
return info;
}
ap_expr_t *ap_expr_make(ap_expr_node_op_e op, const void *a1, const void *a2,
ap_expr_parse_ctx_t *ctx)
{
ap_expr_t *node = apr_palloc(ctx->pool, sizeof(ap_expr_t));
node->node_op = op;
node->node_arg1 = a1;
node->node_arg2 = a2;
return node;
}
static ap_expr_t *ap_expr_info_make(int type, const char *name,
ap_expr_parse_ctx_t *ctx,
const ap_expr_t *arg)
{
ap_expr_t *info = apr_palloc(ctx->pool, sizeof(ap_expr_t));
ap_expr_lookup_parms parms;
parms.type = type;
parms.flags = ctx->flags;
parms.pool = ctx->pool;
parms.ptemp = ctx->ptemp;
parms.name = name;
parms.func = &info->node_arg1;
parms.data = &info->node_arg2;
parms.err = &ctx->error2;
parms.arg = (arg && arg->node_op == op_String) ? arg->node_arg1 : NULL;
if (ctx->lookup_fn(&parms) != OK)
return NULL;
return info;
}
ap_expr_t *ap_expr_str_func_make(const char *name, const ap_expr_t *arg,
ap_expr_parse_ctx_t *ctx)
{
ap_expr_t *info = ap_expr_info_make(AP_EXPR_FUNC_STRING, name, ctx, arg);
if (!info)
return NULL;
info->node_op = op_StringFuncInfo;
return ap_expr_make(op_StringFuncCall, info, arg, ctx);
}
ap_expr_t *ap_expr_list_func_make(const char *name, const ap_expr_t *arg,
ap_expr_parse_ctx_t *ctx)
{
ap_expr_t *info = ap_expr_info_make(AP_EXPR_FUNC_LIST, name, ctx, arg);
if (!info)
return NULL;
info->node_op = op_ListFuncInfo;
return ap_expr_make(op_ListFuncCall, info, arg, ctx);
}
ap_expr_t *ap_expr_unary_op_make(const char *name, const ap_expr_t *arg,
ap_expr_parse_ctx_t *ctx)
{
ap_expr_t *info = ap_expr_info_make(AP_EXPR_FUNC_OP_UNARY, name, ctx, arg);
if (!info)
return NULL;
info->node_op = op_UnaryOpInfo;
return ap_expr_make(op_UnaryOpCall, info, arg, ctx);
}
ap_expr_t *ap_expr_binary_op_make(const char *name, const ap_expr_t *arg1,
const ap_expr_t *arg2, ap_expr_parse_ctx_t *ctx)
{
ap_expr_t *args;
ap_expr_t *info = ap_expr_info_make(AP_EXPR_FUNC_OP_BINARY, name, ctx,
arg2);
if (!info)
return NULL;
info->node_op = op_BinaryOpInfo;
args = ap_expr_make(op_BinaryOpArgs, arg1, arg2, ctx);
return ap_expr_make(op_BinaryOpCall, info, args, ctx);
}
ap_expr_t *ap_expr_var_make(const char *name, ap_expr_parse_ctx_t *ctx)
{
ap_expr_t *node = ap_expr_info_make(AP_EXPR_FUNC_VAR, name, ctx, NULL);
if (!node)
return NULL;
node->node_op = op_Var;
return node;
}
#ifdef AP_EXPR_DEBUG
#define MARK APLOG_MARK,loglevel,0,s
#define DUMP_E_E(op, e1, e2) \
do { ap_log_error(MARK,"%*s%s: %pp %pp", indent, " ", op, e1, e2); \
if (e1) expr_dump_tree(e1, s, loglevel, indent + 2); \
if (e2) expr_dump_tree(e2, s, loglevel, indent + 2); \
} while (0)
#define DUMP_S_E(op, s1, e1) \
do { ap_log_error(MARK,"%*s%s: '%s' %pp", indent, " ", op, (char *)s1, e1); \
if (e1) expr_dump_tree(e1, s, loglevel, indent + 2); \
} while (0)
#define DUMP_S_P(op, s1, p1) \
ap_log_error(MARK,"%*s%s: '%s' %pp", indent, " ", op, (char *)s1, p1);
#define DUMP_P_P(op, p1, p2) \
ap_log_error(MARK,"%*s%s: %pp %pp", indent, " ", op, p1, p2);
#define DUMP_S_S(op, s1, s2) \
ap_log_error(MARK,"%*s%s: '%s' '%s'", indent, " ", op, (char *)s1, (char *)s2)
#define DUMP_P(op, p1) \
ap_log_error(MARK,"%*s%s: %pp", indent, " ", op, p1);
#define DUMP_IP(op, p1) \
ap_log_error(MARK,"%*s%s: %d", indent, " ", op, *(int *)p1);
#define DUMP_S(op, s1) \
ap_log_error(MARK,"%*s%s: '%s'", indent, " ", op, (char *)s1)
#define CASE_OP(op) case op: name = #op ; break;
static void expr_dump_tree(const ap_expr_t *e, const server_rec *s,
int loglevel, int indent)
{
switch (e->node_op) {
/* no arg */
case op_NOP:
case op_True:
case op_False:
{
char *name;
switch (e->node_op) {
CASE_OP(op_NOP);
CASE_OP(op_True);
CASE_OP(op_False);
default:
ap_assert(0);
}
ap_log_error(MARK, "%*s%s", indent, " ", name);
}
break;
/* arg1: string, arg2: expr */
case op_UnaryOpCall:
case op_BinaryOpCall:
case op_BinaryOpArgs:
{
char *name;
switch (e->node_op) {
CASE_OP(op_BinaryOpCall);
CASE_OP(op_UnaryOpCall);
CASE_OP(op_BinaryOpArgs);
default:
ap_assert(0);
}
DUMP_S_E(name, e->node_arg1, e->node_arg2);
}
break;
/* arg1: expr, arg2: expr */
case op_Comp:
case op_Not:
case op_Or:
case op_And:
case op_EQ:
case op_NE:
case op_LT:
case op_LE:
case op_GT:
case op_GE:
case op_STR_EQ:
case op_STR_NE:
case op_STR_LT:
case op_STR_LE:
case op_STR_GT:
case op_STR_GE:
case op_IN:
case op_REG:
case op_NRE:
case op_Concat:
case op_StringFuncCall:
case op_ListFuncCall:
case op_ListElement:
{
char *name;
switch (e->node_op) {
CASE_OP(op_Comp);
CASE_OP(op_Not);
CASE_OP(op_Or);
CASE_OP(op_And);
CASE_OP(op_EQ);
CASE_OP(op_NE);
CASE_OP(op_LT);
CASE_OP(op_LE);
CASE_OP(op_GT);
CASE_OP(op_GE);
CASE_OP(op_STR_EQ);
CASE_OP(op_STR_NE);
CASE_OP(op_STR_LT);
CASE_OP(op_STR_LE);
CASE_OP(op_STR_GT);
CASE_OP(op_STR_GE);
CASE_OP(op_IN);
CASE_OP(op_REG);
CASE_OP(op_NRE);
CASE_OP(op_Concat);
CASE_OP(op_StringFuncCall);
CASE_OP(op_ListFuncCall);
CASE_OP(op_ListElement);
default:
ap_assert(0);
}
DUMP_E_E(name, e->node_arg1, e->node_arg2);
}
break;
/* arg1: string */
case op_Digit:
case op_String:
{
char *name;
switch (e->node_op) {
CASE_OP(op_Digit);
CASE_OP(op_String);
default:
ap_assert(0);
}
DUMP_S(name, e->node_arg1);
}
break;
/* arg1: pointer, arg2: pointer */
case op_Var:
case op_StringFuncInfo:
case op_UnaryOpInfo:
case op_BinaryOpInfo:
case op_ListFuncInfo:
{
char *name;
switch (e->node_op) {
CASE_OP(op_Var);
CASE_OP(op_StringFuncInfo);
CASE_OP(op_UnaryOpInfo);
CASE_OP(op_BinaryOpInfo);
CASE_OP(op_ListFuncInfo);
default:
ap_assert(0);
}
DUMP_P_P(name, e->node_arg1, e->node_arg2);
}
break;
/* arg1: pointer */
case op_Regex:
DUMP_P("op_Regex", e->node_arg1);
break;
/* arg1: pointer to int */
case op_RegexBackref:
DUMP_IP("op_RegexBackref", e->node_arg1);
break;
default:
ap_log_error(MARK, "%*sERROR: INVALID OP %d", indent, " ", e->node_op);
break;
}
}
#endif /* AP_EXPR_DEBUG */
static int ap_expr_eval_unary_op(ap_expr_eval_ctx_t *ctx, const ap_expr_t *info,
const ap_expr_t *arg)
{
const ap_expr_op_unary_t *op_func = info->node_arg1;
const void *data = info->node_arg2;
AP_DEBUG_ASSERT(info->node_op == op_UnaryOpInfo);
AP_DEBUG_ASSERT(op_func != NULL);
AP_DEBUG_ASSERT(data != NULL);
return (*op_func)(ctx, data, ap_expr_eval_word(ctx, arg));
}
static int ap_expr_eval_binary_op(ap_expr_eval_ctx_t *ctx,
const ap_expr_t *info,
const ap_expr_t *args)
{
const ap_expr_op_binary_t *op_func = info->node_arg1;
const void *data = info->node_arg2;
const ap_expr_t *a1 = args->node_arg1;
const ap_expr_t *a2 = args->node_arg2;
AP_DEBUG_ASSERT(info->node_op == op_BinaryOpInfo);
AP_DEBUG_ASSERT(args->node_op == op_BinaryOpArgs);
AP_DEBUG_ASSERT(op_func != NULL);
AP_DEBUG_ASSERT(data != NULL);
return (*op_func)(ctx, data, ap_expr_eval_word(ctx, a1),
ap_expr_eval_word(ctx, a2));
}
static int ap_expr_eval(ap_expr_eval_ctx_t *ctx, const ap_expr_t *node)
{
const ap_expr_t *e1 = node->node_arg1;
const ap_expr_t *e2 = node->node_arg2;
switch (node->node_op) {
case op_True:
return 1;
case op_False:
return 0;
case op_Not:
return (!ap_expr_eval(ctx, e1));
case op_Or:
return (ap_expr_eval(ctx, e1) || ap_expr_eval(ctx, e2));
case op_And:
return (ap_expr_eval(ctx, e1) && ap_expr_eval(ctx, e2));
case op_UnaryOpCall:
return ap_expr_eval_unary_op(ctx, e1, e2);
case op_BinaryOpCall:
return ap_expr_eval_binary_op(ctx, e1, e2);
case op_Comp:
if (ctx->info->flags & AP_EXPR_FLAGS_SSL_EXPR_COMPAT)
return ssl_expr_eval_comp(ctx, e1);
else
return ap_expr_eval_comp(ctx, e1);
default:
*ctx->err = "Internal evaluation error: Unknown expression node";
return FALSE;
}
}
AP_DECLARE(int) ap_expr_exec(request_rec *r, const ap_expr_info_t *info,
const char **err)
{
return ap_expr_exec_re(r, info, 0, NULL, NULL, err);
}
AP_DECLARE(int) ap_expr_exec_ctx(ap_expr_eval_ctx_t *ctx)
{
int rc;
AP_DEBUG_ASSERT(ctx->p != NULL);
/* XXX: allow r, c == NULL */
AP_DEBUG_ASSERT(ctx->r != NULL);
AP_DEBUG_ASSERT(ctx->c != NULL);
AP_DEBUG_ASSERT(ctx->s != NULL);
AP_DEBUG_ASSERT(ctx->err != NULL);
AP_DEBUG_ASSERT(ctx->info != NULL);
if (ctx->re_pmatch) {
AP_DEBUG_ASSERT(ctx->re_source != NULL);
AP_DEBUG_ASSERT(ctx->re_nmatch > 0);
}
*ctx->err = NULL;
rc = ap_expr_eval(ctx, ctx->info->root_node);
if (*ctx->err != NULL) {
ap_log_rerror(LOG_MARK(ctx->info), APLOG_ERR, 0, ctx->r,
"Evaluation of expression from %s:%d failed: %s",
ctx->info->filename, ctx->info->line_number, *ctx->err);
return -1;
} else {
rc = rc ? 1 : 0;
ap_log_rerror(LOG_MARK(ctx->info), APLOG_TRACE4, 0, ctx->r,
"Evaluation of expression from %s:%d gave: %d",
ctx->info->filename, ctx->info->line_number, rc);
if (ctx->vary_this)
apr_table_merge(ctx->r->headers_out, "Vary", *ctx->vary_this);
return rc;
}
}
AP_DECLARE(int) ap_expr_exec_re(request_rec *r, const ap_expr_info_t *info,
apr_size_t nmatch, ap_regmatch_t *pmatch,
const char **source, const char **err)
{
ap_expr_eval_ctx_t ctx;
int dont_vary = (info->flags & AP_EXPR_FLAGS_DONT_VARY);
const char *tmp_source = NULL, *vary_this = NULL;
ap_regmatch_t tmp_pmatch[10];
ctx.r = r;
ctx.c = r->connection;
ctx.s = r->server;
ctx.p = r->pool;
ctx.err = err;
ctx.info = info;
ctx.re_nmatch = nmatch;
ctx.re_pmatch = pmatch;
ctx.re_source = source;
ctx.vary_this = dont_vary ? NULL : &vary_this;
ctx.data = NULL;
if (!pmatch) {
ctx.re_nmatch = 10;
ctx.re_pmatch = tmp_pmatch;
ctx.re_source = &tmp_source;
}
return ap_expr_exec_ctx(&ctx);
}
static void add_vary(ap_expr_eval_ctx_t *ctx, const char *name)
{
if (!ctx->vary_this)
return;
if (*ctx->vary_this) {
*ctx->vary_this = apr_pstrcat(ctx->p, *ctx->vary_this, ", ", name,
NULL);
}
else {
*ctx->vary_this = name;
}
}
static const char *req_table_func(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg)
{
const char *name = (const char *)data;
apr_table_t *t;
if (!ctx->r)
return "";
if (name[2] == 's') { /* resp */
/* Try r->headers_out first, fall back on err_headers_out. */
const char *v = apr_table_get(ctx->r->headers_out, arg);
if (v) {
return v;
}
t = ctx->r->err_headers_out;
}
else if (name[0] == 'n') /* notes */
t = ctx->r->notes;
else if (name[3] == 'e') /* reqenv */
t = ctx->r->subprocess_env;
else { /* req, http */
t = ctx->r->headers_in;
add_vary(ctx, arg);
}
return apr_table_get(t, arg);
}
static const char *env_func(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg)
{
const char *res;
/* this order is for ssl_expr compatibility */
if (ctx->r) {
if ((res = apr_table_get(ctx->r->notes, arg)) != NULL)
return res;
else if ((res = apr_table_get(ctx->r->subprocess_env, arg)) != NULL)
return res;
}
return getenv(arg);
}
static const char *osenv_func(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg)
{
return getenv(arg);
}
static const char *tolower_func(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg)
{
char *result = apr_pstrdup(ctx->p, arg);
ap_str_tolower(result);
return result;
}
static const char *toupper_func(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg)
{
char *p;
char *result = apr_pstrdup(ctx->p, arg);
for (p = result; *p; ++p) {
*p = apr_toupper(*p);
}
return result;
}
static const char *escape_func(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg)
{
return ap_escape_uri(ctx->p, arg);
}
#define MAX_FILE_SIZE 10*1024*1024
static const char *file_func(ap_expr_eval_ctx_t *ctx, const void *data,
char *arg)
{
apr_file_t *fp;
char *buf;
apr_off_t offset;
apr_size_t len;
apr_finfo_t finfo;
if (apr_file_open(&fp, arg, APR_READ|APR_BUFFERED,
APR_OS_DEFAULT, ctx->p) != APR_SUCCESS) {
*ctx->err = apr_psprintf(ctx->p, "Cannot open file %s", arg);
return "";
}
apr_file_info_get(&finfo, APR_FINFO_SIZE, fp);
if (finfo.size > MAX_FILE_SIZE) {
*ctx->err = apr_psprintf(ctx->p, "File %s too large", arg);
apr_file_close(fp);
return "";
}
len = (apr_size_t)finfo.size;
if (len == 0) {
apr_file_close(fp);
return "";
}
else {
if ((buf = (char *)apr_palloc(ctx->p, sizeof(char)*(len+1))) == NULL) {
*ctx->err = "Cannot allocate memory";
apr_file_close(fp);
return "";
}
offset = 0;
apr_file_seek(fp, APR_SET, &offset);
if (apr_file_read(fp, buf, &len) != APR_SUCCESS) {
*ctx->err = apr_psprintf(ctx->p, "Cannot read from file %s", arg);
apr_file_close(fp);
return "";
}
buf[len] = '\0';
}
apr_file_close(fp);
return buf;
}
static const char *filesize_func(ap_expr_eval_ctx_t *ctx, const void *data,
char *arg)
{
apr_finfo_t sb;
if (apr_stat(&sb, arg, APR_FINFO_MIN, ctx->p) == APR_SUCCESS
&& sb.filetype == APR_REG && sb.size > 0)
return apr_psprintf(ctx->p, "%" APR_OFF_T_FMT, sb.size);
else
return "0";
}
static const char *unescape_func(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg)
{
char *result = apr_pstrdup(ctx->p, arg);
if (ap_unescape_url(result))
return "";
else
return result;
}
static int op_nz(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg)
{
const char *name = (const char *)data;
if (name[0] == 'z')
return (arg[0] == '\0');
else
return (arg[0] != '\0');
}
static int op_file_min(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg)
{
apr_finfo_t sb;
const char *name = (const char *)data;
if (apr_stat(&sb, arg, APR_FINFO_MIN, ctx->p) != APR_SUCCESS)
return FALSE;
switch (name[0]) {
case 'd':
return (sb.filetype == APR_DIR);
case 'e':
return TRUE;
case 'f':
return (sb.filetype == APR_REG);
case 's':
return (sb.filetype == APR_REG && sb.size > 0);
default:
ap_assert(0);
}
return FALSE;
}
static int op_file_link(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg)
{
apr_finfo_t sb;
#if !defined(OS2)
if (apr_stat(&sb, arg, APR_FINFO_MIN | APR_FINFO_LINK, ctx->p) == APR_SUCCESS
&& sb.filetype == APR_LNK) {
return TRUE;
}
#endif
return FALSE;
}
static int op_file_xbit(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg)
{
apr_finfo_t sb;
if (apr_stat(&sb, arg, APR_FINFO_PROT| APR_FINFO_LINK, ctx->p) == APR_SUCCESS
&& (sb.protection & (APR_UEXECUTE | APR_GEXECUTE | APR_WEXECUTE))) {
return TRUE;
}
return FALSE;
}
static int op_url_subr(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg)
{
int rc = FALSE;
request_rec *rsub, *r = ctx->r;
if (!r)
return FALSE;
/* avoid some infinite recursions */
if (r->main && r->main->uri && r->uri && strcmp(r->main->uri, r->uri) == 0)
return FALSE;
rsub = ap_sub_req_lookup_uri(arg, r, NULL);
if (rsub->status < 400) {
rc = TRUE;
}
ap_log_rerror(LOG_MARK(ctx->info), APLOG_TRACE5, 0, r,
"Subrequest for -U %s at %s:%d gave status: %d",
arg, ctx->info->filename, ctx->info->line_number,
rsub->status);
ap_destroy_sub_req(rsub);
return rc;
}
static int op_file_subr(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg)
{
int rc = FALSE;
apr_finfo_t sb;
request_rec *rsub, *r = ctx->r;
if (!r)
return FALSE;
rsub = ap_sub_req_lookup_file(arg, r, NULL);
if (rsub->status < 300 &&
/* double-check that file exists since default result is 200 */
apr_stat(&sb, rsub->filename, APR_FINFO_MIN, ctx->p) == APR_SUCCESS) {
rc = TRUE;
}
ap_log_rerror(LOG_MARK(ctx->info), APLOG_TRACE5, 0, r,
"Subrequest for -F %s at %s:%d gave status: %d",
arg, ctx->info->filename, ctx->info->line_number,
rsub->status);
ap_destroy_sub_req(rsub);
return rc;
}
APR_DECLARE_OPTIONAL_FN(int, ssl_is_https, (conn_rec *));
static APR_OPTIONAL_FN_TYPE(ssl_is_https) *is_https = NULL;
static const char *conn_var_names[] = {
"REMOTE_ADDR", /* 0 */
"HTTPS", /* 1 */
"IPV6", /* 2 */
"CONN_LOG_ID", /* 3 */
NULL
};
static const char *conn_var_fn(ap_expr_eval_ctx_t *ctx, const void *data)
{
int index = ((const char **)data - conn_var_names);
conn_rec *c = ctx->c;
if (!c)
return "";
switch (index) {
case 0:
return c->remote_ip;
case 1:
if (is_https && is_https(c))
return "on";
else
return "off";
case 2:
#if APR_HAVE_IPV6
{
apr_sockaddr_t *addr = c->remote_addr;
if (addr->family == AF_INET6
&& !IN6_IS_ADDR_V4MAPPED((struct in6_addr *)addr->ipaddr_ptr))
return "on";
else
return "off";
}
#else
return "off";
#endif
case 3:
return c->log_id;
default:
ap_assert(0);
return NULL;
}
}
static const char *request_var_names[] = {
"REQUEST_METHOD", /* 0 */
"REQUEST_SCHEME", /* 1 */
"REQUEST_URI", /* 2 */
"REQUEST_FILENAME", /* 3 */
"REMOTE_HOST", /* 4 */
"REMOTE_IDENT", /* 5 */
"REMOTE_USER", /* 6 */
"SERVER_ADMIN", /* 7 */
"SERVER_NAME", /* 8 */
"SERVER_PORT", /* 9 */
"SERVER_PROTOCOL", /* 10 */
"SCRIPT_FILENAME", /* 11 */
"PATH_INFO", /* 12 */
"QUERY_STRING", /* 13 */
"IS_SUBREQ", /* 14 */
"DOCUMENT_ROOT", /* 15 */
"AUTH_TYPE", /* 16 */
"THE_REQUEST", /* 17 */
"CONTENT_TYPE", /* 18 */
"HANDLER", /* 19 */
"REQUEST_LOG_ID", /* 20 */
"SCRIPT_USER", /* 21 */
"SCRIPT_GROUP", /* 22 */
"DOCUMENT_URI", /* 23 */
"LAST_MODIFIED", /* 24 */
NULL
};
static const char *request_var_fn(ap_expr_eval_ctx_t *ctx, const void *data)
{
int index = ((const char **)data - request_var_names);
request_rec *r = ctx->r;
if (!r)
return "";
switch (index) {
case 0:
return r->method;
case 1:
return ap_http_scheme(r);
case 2:
return r->uri;
case 3:
return r->filename;
case 4:
return ap_get_remote_host(r->connection, r->per_dir_config,
REMOTE_NAME, NULL);
case 5:
return ap_get_remote_logname(r);
case 6:
return r->user;
case 7:
return r->server->server_admin;
case 8:
return ap_get_server_name(r);
case 9:
return apr_psprintf(ctx->p, "%u", ap_get_server_port(r));
case 10:
return r->protocol;
case 11:
return r->filename;
case 12:
return r->path_info;
case 13:
return r->args;
case 14:
return (r->main != NULL ? "true" : "false");
case 15:
return ap_document_root(r);
case 16:
return r->ap_auth_type;
case 17:
return r->the_request;
case 18:
return r->content_type;
case 19:
return r->handler;
case 20:
return r->log_id;
case 21:
{
char *result = "";
if (r->finfo.valid & APR_FINFO_USER)
apr_uid_name_get(&result, r->finfo.user, ctx->p);
return result;
}
case 22:
{
char *result = "";
if (r->finfo.valid & APR_FINFO_USER)
apr_gid_name_get(&result, r->finfo.group, ctx->p);
return result;
}
case 23:
return r->uri;
case 24:
{
apr_time_exp_t tm;
apr_time_exp_lt(&tm, r->mtime);
return apr_psprintf(ctx->p, "%02d%02d%02d%02d%02d%02d%02d",
(tm.tm_year / 100) + 19, (tm.tm_year % 100),
tm.tm_mon+1, tm.tm_mday, tm.tm_hour, tm.tm_min,
tm.tm_sec);
}
default:
ap_assert(0);
return NULL;
}
}
static const char *req_header_var_names[] = {
"HTTP_USER_AGENT",
"HTTP_PROXY_CONNECTION",
"HTTP_REFERER",
"HTTP_COOKIE",
"HTTP_FORWARDED",
"HTTP_HOST",
"HTTP_ACCEPT",
NULL
};
static const char *req_header_header_names[] = {
"User-Agent",
"Proxy-Connection",
"Referer",
"Cookie",
"Forwarded",
"Host",
"Accept"
};
static const char *req_header_var_fn(ap_expr_eval_ctx_t *ctx, const void *data)
{
const char **varname = (const char **)data;
int index = (varname - req_header_var_names);
const char *name;
AP_DEBUG_ASSERT(index < 6);
if (!ctx->r)
return "";
name = req_header_header_names[index];
add_vary(ctx, name);
return apr_table_get(ctx->r->headers_in, name);
}
static const char *misc_var_names[] = {
"TIME_YEAR", /* 0 */
"TIME_MON", /* 1 */
"TIME_DAY", /* 2 */
"TIME_HOUR", /* 3 */
"TIME_MIN", /* 4 */
"TIME_SEC", /* 5 */
"TIME_WDAY", /* 6 */
"TIME", /* 7 */
"SERVER_SOFTWARE", /* 8 */
"API_VERSION", /* 9 */
NULL
};
static const char *misc_var_fn(ap_expr_eval_ctx_t *ctx, const void *data)
{
apr_time_exp_t tm;
int index = ((const char **)data - misc_var_names);
apr_time_exp_lt(&tm, apr_time_now());
switch (index) {
case 0:
return apr_psprintf(ctx->p, "%02d%02d", (tm.tm_year / 100) + 19,
tm.tm_year % 100);
case 1:
return apr_psprintf(ctx->p, "%02d", tm.tm_mon+1);
case 2:
return apr_psprintf(ctx->p, "%02d", tm.tm_mday);
case 3:
return apr_psprintf(ctx->p, "%02d", tm.tm_hour);
case 4:
return apr_psprintf(ctx->p, "%02d", tm.tm_min);
case 5:
return apr_psprintf(ctx->p, "%02d", tm.tm_sec);
case 6:
return apr_psprintf(ctx->p, "%d", tm.tm_wday);
case 7:
return apr_psprintf(ctx->p, "%02d%02d%02d%02d%02d%02d%02d",
(tm.tm_year / 100) + 19, (tm.tm_year % 100),
tm.tm_mon+1, tm.tm_mday, tm.tm_hour, tm.tm_min,
tm.tm_sec);
case 8:
return ap_get_server_banner();
case 9:
return apr_itoa(ctx->p, MODULE_MAGIC_NUMBER);
default:
ap_assert(0);
}
return NULL;
}
static int subnet_parse_arg(ap_expr_lookup_parms *parms)
{
apr_ipsubnet_t *subnet;
const char *addr = parms->arg;
const char *mask;
apr_status_t ret;
if (!parms->arg) {
*parms->err = apr_psprintf(parms->ptemp,
"-%s requires subnet/netmask as constant argument",
parms->name);
return !OK;
}
mask = ap_strchr_c(addr, '/');
if (mask) {
addr = apr_pstrmemdup(parms->ptemp, addr, mask - addr);
mask++;
}
ret = apr_ipsubnet_create(&subnet, addr, mask, parms->pool);
if (ret != APR_SUCCESS) {
*parms->err = "parsing of subnet/netmask failed";
return !OK;
}
*parms->data = subnet;
return OK;
}
static int op_ipmatch(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg1,
const char *arg2)
{
apr_ipsubnet_t *subnet = (apr_ipsubnet_t *)data;
apr_sockaddr_t *saddr;
AP_DEBUG_ASSERT(subnet != NULL);
/* maybe log an error if this goes wrong? */
if (apr_sockaddr_info_get(&saddr, arg1, APR_UNSPEC, 0, 0, ctx->p) != APR_SUCCESS)
return FALSE;
return apr_ipsubnet_test(subnet, saddr);
}
static int op_R(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg1)
{
apr_ipsubnet_t *subnet = (apr_ipsubnet_t *)data;
AP_DEBUG_ASSERT(subnet != NULL);
if (!ctx->c)
return FALSE;
return apr_ipsubnet_test(subnet, ctx->c->remote_addr);
}
static int op_T(ap_expr_eval_ctx_t *ctx, const void *data, const char *arg)
{
switch (arg[0]) {
case '\0':
return FALSE;
case 'o':
case 'O':
return strcasecmp(arg, "off") == 0 ? FALSE : TRUE;
case 'n':
case 'N':
return strcasecmp(arg, "no") == 0 ? FALSE : TRUE;
case 'f':
case 'F':
return strcasecmp(arg, "false") == 0 ? FALSE : TRUE;
case '0':
return arg[1] == '\0' ? FALSE : TRUE;
default:
return TRUE;
}
}
static int op_fnmatch(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg1, const char *arg2)
{
return (APR_SUCCESS == apr_fnmatch(arg2, arg1, APR_FNM_PATHNAME));
}
static int op_strmatch(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg1, const char *arg2)
{
return (APR_SUCCESS == apr_fnmatch(arg2, arg1, 0));
}
static int op_strcmatch(ap_expr_eval_ctx_t *ctx, const void *data,
const char *arg1, const char *arg2)
{
return (APR_SUCCESS == apr_fnmatch(arg2, arg1, APR_FNM_CASE_BLIND));
}
struct expr_provider_single {
const void *func;
const char *name;
ap_expr_lookup_fn_t *arg_parsing_func;
int restricted;
};
struct expr_provider_multi {
const void *func;
const char **names;
};
static const struct expr_provider_multi var_providers[] = {
{ misc_var_fn, misc_var_names },
{ req_header_var_fn, req_header_var_names },
{ request_var_fn, request_var_names },
{ conn_var_fn, conn_var_names },
{ NULL, NULL }
};
static const struct expr_provider_single string_func_providers[] = {
{ osenv_func, "osenv", NULL, 0 },
{ env_func, "env", NULL, 0 },
{ req_table_func, "resp", NULL, 0 },
{ req_table_func, "req", NULL, 0 },
/* 'http' as alias for 'req' for compatibility with ssl_expr */
{ req_table_func, "http", NULL, 0 },
{ req_table_func, "note", NULL, 0 },
{ req_table_func, "reqenv", NULL, 0 },
{ tolower_func, "tolower", NULL, 0 },
{ toupper_func, "toupper", NULL, 0 },
{ escape_func, "escape", NULL, 0 },
{ unescape_func, "unescape", NULL, 0 },
{ file_func, "file", NULL, 1 },
{ filesize_func, "filesize", NULL, 1 },
{ NULL, NULL, NULL}
};
/* XXX: base64 encode/decode ? */
static const struct expr_provider_single unary_op_providers[] = {
{ op_nz, "n", NULL, 0 },
{ op_nz, "z", NULL, 0 },
{ op_R, "R", subnet_parse_arg, 0 },
{ op_T, "T", NULL, 0 },
{ op_file_min, "d", NULL, 1 },
{ op_file_min, "e", NULL, 1 },
{ op_file_min, "f", NULL, 1 },
{ op_file_min, "s", NULL, 1 },
{ op_file_link, "L", NULL, 1 },
{ op_file_link, "h", NULL, 1 },
{ op_file_xbit, "x", NULL, 1 },
{ op_file_subr, "F", NULL, 0 },
{ op_url_subr, "U", NULL, 0 },
{ op_url_subr, "A", NULL, 0 },
{ NULL, NULL, NULL }
};
static const struct expr_provider_single binary_op_providers[] = {
{ op_ipmatch, "ipmatch", subnet_parse_arg, 0 },
{ op_fnmatch, "fnmatch", NULL, 0 },
{ op_strmatch, "strmatch", NULL, 0 },
{ op_strcmatch, "strcmatch", NULL, 0 },
{ NULL, NULL, NULL }
};
static int core_expr_lookup(ap_expr_lookup_parms *parms)
{
switch (parms->type) {
case AP_EXPR_FUNC_VAR: {
const struct expr_provider_multi *prov = var_providers;
while (prov->func) {
const char **name = prov->names;
while (*name) {
if (strcasecmp(*name, parms->name) == 0) {
*parms->func = prov->func;
*parms->data = name;
return OK;
}
name++;
}
prov++;
}
}
break;
case AP_EXPR_FUNC_STRING:
case AP_EXPR_FUNC_OP_UNARY:
case AP_EXPR_FUNC_OP_BINARY: {
const struct expr_provider_single *prov;
switch (parms->type) {
case AP_EXPR_FUNC_STRING:
prov = string_func_providers;
break;
case AP_EXPR_FUNC_OP_UNARY:
prov = unary_op_providers;
break;
case AP_EXPR_FUNC_OP_BINARY:
prov = binary_op_providers;
break;
default:
ap_assert(0);
}
while (prov->func) {
if (strcasecmp(prov->name, parms->name) == 0) {
if ((parms->flags & AP_EXPR_FLAGS_RESTRICTED)
&& prov->restricted) {
*parms->err =
apr_psprintf(parms->ptemp,
"%s%s not available in restricted context",
(parms->type == AP_EXPR_FUNC_STRING) ? "" : "-",
prov->name);
return !OK;
}
*parms->func = prov->func;
if (prov->arg_parsing_func) {
return prov->arg_parsing_func(parms);
}
else {
*parms->data = prov->name;
return OK;
}
}
prov++;
}
}
break;
default:
break;
}
return DECLINED;
}
static int expr_lookup_not_found(ap_expr_lookup_parms *parms)
{
const char *type;
switch (parms->type) {
case AP_EXPR_FUNC_VAR:
type = "Variable";
break;
case AP_EXPR_FUNC_STRING:
type = "Function";
break;
case AP_EXPR_FUNC_LIST:
type = "List-returning function";
break;
case AP_EXPR_FUNC_OP_UNARY:
type = "Unary operator";
break;
case AP_EXPR_FUNC_OP_BINARY:
type = "Binary operator";
break;
default:
*parms->err = "Inavalid expression type in expr_lookup";
return !OK;
}
*parms->err = apr_psprintf(parms->ptemp, "%s '%s' does not exist", type,
parms->name);
return !OK;
}
static int ap_expr_post_config(apr_pool_t *pconf, apr_pool_t *plog,
apr_pool_t *ptemp, server_rec *s)
{
is_https = APR_RETRIEVE_OPTIONAL_FN(ssl_is_https);
apr_pool_cleanup_register(pconf, &is_https, ap_pool_cleanup_set_null,
apr_pool_cleanup_null);
return OK;
}
void ap_expr_init(apr_pool_t *p)
{
ap_hook_expr_lookup(core_expr_lookup, NULL, NULL, APR_HOOK_MIDDLE);
ap_hook_expr_lookup(expr_lookup_not_found, NULL, NULL, APR_HOOK_REALLY_LAST);
ap_hook_post_config(ap_expr_post_config, NULL, NULL, APR_HOOK_MIDDLE);
}