Commit 4732d2b6 authored by Eric Covener's avatar Eric Covener
Browse files

add RewriteOptions LongURLOptimization 

Variable expansion in RewriteCond causes strings to be duplicated
out of r->pool.  If the variables are long and many conditions
are evaluated, r->pool can get seriously bloated.

Clear the memory used for variable expansion for each set of conditons
once the set of conditions fails to match.




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1798938 13f79535-47bb-0310-9956-ffa450edef68
parent f46424be

CHANGES

+4 −0
Original line number Diff line number Diff line 
                                                         -*- coding: utf-8 -*-

Changes with Apache 2.5.0



  *) mod_rewrite: Add 'RewriteOptions LongURLOptimization' to free memory

     from each set of unmatched rewrite conditions.

     [Eric Covener]



  *) Allow the argument to <IfFile>, <IfDefine>, <IfSection>, <IfDirective>, 

     and <IfModule> to be quoted.  This is primarily for the benefit of

     <IfFile>. [Eric Covener]

docs/manual/mod/mod_rewrite.xml

+7 −0
Original line number Diff line number Diff line
@@ -291,6 +291,13 @@ LogLevel alert rewrite:trace3 
         URL.  Available in 2.4.26 and later.</p>

      </dd>



      <dt><code>LongURLOptimization</code></dt>

      <dd>

      <p>This option reduces memory usage of long, unoptimized rule sets 

         that repeatedly expand long values in RewriteCond and RewriteRule

         variables. Available in 2.5 and later.</p>

      </dd>



      </dl>

</usage>

modules/mappers/mod_rewrite.c

+28 −12
Original line number Diff line number Diff line
@@ -203,6 +203,7 @@ static const char* really_last_key = "rewrite_really_last"; 
#define OPTION_IGNORE_INHERIT       (1<<8)

#define OPTION_IGNORE_CONTEXT_INFO  (1<<9)

#define OPTION_LEGACY_PREFIX_DOCROOT (1<<10)

#define OPTION_LONGOPT              (1<<11)



#ifndef RAND_MAX

#define RAND_MAX 32767
@@ -397,6 +398,7 @@ typedef struct { 
    char        *perdir;

    backrefinfo briRR;

    backrefinfo briRC;

    apr_pool_t *temp_pool;

} rewrite_ctx;



/*
@@ -2286,14 +2288,13 @@ static APR_INLINE char *find_char_in_curlies(char *s, int c) 
 * are interpreted by a later expansion, producing results that

 * were not intended by the administrator.

 */

static char *do_expand(char *input, rewrite_ctx *ctx, rewriterule_entry *entry)

static char *do_expand(char *input, rewrite_ctx *ctx, rewriterule_entry *entry, apr_pool_t *pool)

{

    result_list *result, *current;

    result_list sresult[SMALL_EXPANSION];

    unsigned spc = 0;

    apr_size_t span, inputlen, outlen;

    char *p, *c;

    apr_pool_t *pool = ctx->r->pool;



    span = strcspn(input, "\\$%");

    inputlen = strlen(input);
@@ -2398,10 +2399,10 @@ static char *do_expand(char *input, rewrite_ctx *ctx, rewriterule_entry *entry) 
                    }



                    /* reuse of key variable as result */

                    key = lookup_map(ctx->r, map, do_expand(key, ctx, entry));

                    key = lookup_map(ctx->r, map, do_expand(key, ctx, entry, pool));



                    if (!key && dflt && *dflt) {

                        key = do_expand(dflt, ctx, entry);

                        key = do_expand(dflt, ctx, entry, pool);

                    }



                    if (key) {
@@ -2499,7 +2500,7 @@ static void do_expand_env(data_item *env, rewrite_ctx *ctx) 
    char *name, *val;



    while (env) {

        name = do_expand(env->data, ctx, NULL);

        name = do_expand(env->data, ctx, NULL, ctx->r->pool);

        if (*name == '!') {

            name++;

            apr_table_unset(ctx->r->subprocess_env, name);
@@ -2626,7 +2627,7 @@ static void add_cookie(request_rec *r, char *s) 
static void do_expand_cookie(data_item *cookie, rewrite_ctx *ctx)

{

    while (cookie) {

        add_cookie(ctx->r, do_expand(cookie->data, ctx, NULL));

        add_cookie(ctx->r, do_expand(cookie->data, ctx, NULL, ctx->r->pool));

        cookie = cookie->next;

    }
@@ -3037,6 +3038,9 @@ static const char *cmd_rewriteoptions(cmd_parms *cmd, 
        else if (!strcasecmp(w, "legacyprefixdocroot")) {

            options |= OPTION_LEGACY_PREFIX_DOCROOT;

        }

        else if (!strcasecmp(w, "LongURLOptimization")) {

            options |= OPTION_LONGOPT;

        }

        else {

            return apr_pstrcat(cmd->pool, "RewriteOptions: unknown option '",

                               w, "'", NULL);
@@ -3867,7 +3871,7 @@ static APR_INLINE int compare_lexicography(char *a, char *b) 
/*

 * Apply a single rewriteCond

 */

static int apply_rewrite_cond(rewritecond_entry *p, rewrite_ctx *ctx)

static int apply_rewrite_cond(rewritecond_entry *p, rewrite_ctx *ctx, apr_pool_t *pool)

{

    char *input = NULL;

    apr_finfo_t sb;
@@ -3877,7 +3881,7 @@ static int apply_rewrite_cond(rewritecond_entry *p, rewrite_ctx *ctx) 
    int basis;



    if (p->ptype != CONDPAT_AP_EXPR)

        input = do_expand(p->input, ctx, NULL);

        input = do_expand(p->input, ctx, NULL, pool);



    switch (p->ptype) {

    case CONDPAT_FILE_EXISTS:
@@ -4041,7 +4045,7 @@ static APR_INLINE void force_type_handler(rewriterule_entry *p, 
    char *expanded;



    if (p->forced_mimetype) {

        expanded = do_expand(p->forced_mimetype, ctx, p);

        expanded = do_expand(p->forced_mimetype, ctx, p, ctx->r->pool);



        if (*expanded) {

            ap_str_tolower(expanded);
@@ -4055,7 +4059,7 @@ static APR_INLINE void force_type_handler(rewriterule_entry *p, 
    }



    if (p->forced_handler) {

        expanded = do_expand(p->forced_handler, ctx, p);

        expanded = do_expand(p->forced_handler, ctx, p, ctx->r->pool);



        if (*expanded) {

            ap_str_tolower(expanded);
@@ -4152,7 +4156,7 @@ static int apply_rewrite_rule(rewriterule_entry *p, rewrite_ctx *ctx) 
    for (i = 0; i < rewriteconds->nelts; ++i) {

        rewritecond_entry *c = &conds[i];



        rc = apply_rewrite_cond(c, ctx);

        rc = apply_rewrite_cond(c, ctx,  ctx->temp_pool ? ctx->temp_pool : r->pool);

        /*

         * Reset vary_this if the novary flag is set for this condition.

         */
@@ -4174,6 +4178,9 @@ static int apply_rewrite_rule(rewriterule_entry *p, rewrite_ctx *ctx) 
            }

        }

        else if (!rc) {

            if (ctx->temp_pool) { 

                apr_pool_clear(ctx->temp_pool);

            }

            return 0;

        }
@@ -4191,7 +4198,7 @@ static int apply_rewrite_rule(rewriterule_entry *p, rewrite_ctx *ctx) 


    /* expand the result */

    if (!(p->flags & RULEFLAG_NOSUB)) {

        newuri = do_expand(p->output, ctx, p);

        newuri = do_expand(p->output, ctx, p, ctx->r->pool);

        rewritelog((r, 2, ctx->perdir, "rewrite '%s' -> '%s'", ctx->uri,

                    newuri));

    }
@@ -4329,11 +4336,20 @@ static int apply_rewrite_list(request_rec *r, apr_array_header_t *rewriterules, 
    int s;

    rewrite_ctx *ctx;

    int round = 1;

    rewrite_server_conf *sconf = ap_get_module_config(

                                 r->server->module_config, &rewrite_module);



    ctx = apr_palloc(r->pool, sizeof(*ctx));

    ctx->perdir = perdir;

    ctx->r = r;



    if (sconf->options & OPTION_LONGOPT) { 

        apr_pool_create(&(ctx->temp_pool), r->pool);

    }

    else { 

        ctx->temp_pool = NULL;

    }



    /*

     *  Iterate over all existing rules

     */