
/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <ngx_http_perl_module.h>


typedef struct {
    PerlInterpreter  **free_perls;
    ngx_uint_t         interp;
    ngx_uint_t         nalloc;
    ngx_uint_t         interp_max;

    PerlInterpreter   *perl;
    ngx_str_t          modules;
    ngx_array_t        requires;
} ngx_http_perl_main_conf_t;


typedef struct {
    SV                *sub;
    ngx_str_t          handler;
} ngx_http_perl_loc_conf_t;


typedef struct {
    SV                *sub;
    ngx_str_t          handler;
} ngx_http_perl_variable_t;


typedef struct {
    SV                *sv;
    PerlInterpreter   *perl;
} ngx_http_perl_cleanup_t;


#if (NGX_HTTP_SSI)
static ngx_int_t ngx_http_perl_ssi(ngx_http_request_t *r,
    ngx_http_ssi_ctx_t *ssi_ctx, ngx_str_t **params);
#endif

static ngx_int_t
    ngx_http_perl_get_interpreter(ngx_http_perl_main_conf_t *pmcf,
    PerlInterpreter **perl, ngx_log_t *log);
static ngx_inline void
    ngx_http_perl_free_interpreter(ngx_http_perl_main_conf_t *pmcf,
    PerlInterpreter *perl);
static char *ngx_http_perl_init_interpreter(ngx_conf_t *cf,
    ngx_http_perl_main_conf_t *pmcf);
static PerlInterpreter *
    ngx_http_perl_create_interpreter(ngx_http_perl_main_conf_t *pmcf,
    ngx_log_t *log);
static ngx_int_t ngx_http_perl_run_requires(pTHX_ ngx_array_t *requires,
    ngx_log_t *log);
static ngx_int_t ngx_http_perl_call_handler(pTHX_ ngx_http_request_t *r,
    SV *sub, ngx_str_t **args, ngx_str_t *handler, ngx_str_t *rv);
static void ngx_http_perl_eval_anon_sub(pTHX_ ngx_str_t *handler, SV **sv);

static ngx_int_t ngx_http_perl_preconfiguration(ngx_conf_t *cf);
static void *ngx_http_perl_create_main_conf(ngx_conf_t *cf);
static char *ngx_http_perl_init_main_conf(ngx_conf_t *cf, void *conf);
static void *ngx_http_perl_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_perl_merge_loc_conf(ngx_conf_t *cf, void *parent,
    void *child);
static char *ngx_http_perl_require(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_perl(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static char *ngx_http_perl_set(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static char *ngx_http_perl_interp_max_unsupported(ngx_conf_t *cf, void *post,
    void *data);
#if (NGX_HAVE_PERL_CLONE || NGX_HAVE_PERL_MULTIPLICITY)
static void ngx_http_perl_cleanup_perl(void *data);
#endif
static void ngx_http_perl_cleanup_sv(void *data);


static ngx_conf_post_handler_pt  ngx_http_perl_interp_max_p =
    ngx_http_perl_interp_max_unsupported;


static ngx_command_t  ngx_http_perl_commands[] = {

    { ngx_string("perl_modules"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_MAIN_CONF_OFFSET,
      offsetof(ngx_http_perl_main_conf_t, modules),
      NULL },

    { ngx_string("perl_require"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
      ngx_http_perl_require,
      NGX_HTTP_MAIN_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("perl_interp_max"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_MAIN_CONF_OFFSET,
      offsetof(ngx_http_perl_main_conf_t, interp_max),
      &ngx_http_perl_interp_max_p },

    { ngx_string("perl"),
      NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_perl,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("perl_set"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE2,
      ngx_http_perl_set,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_perl_module_ctx = {
    ngx_http_perl_preconfiguration,        /* preconfiguration */
    NULL,                                  /* postconfiguration */

    ngx_http_perl_create_main_conf,        /* create main configuration */
    ngx_http_perl_init_main_conf,          /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    ngx_http_perl_create_loc_conf,         /* create location configuration */
    ngx_http_perl_merge_loc_conf           /* merge location configuration */
};


ngx_module_t  ngx_http_perl_module = {
    NGX_MODULE_V1,
    &ngx_http_perl_module_ctx,             /* module context */
    ngx_http_perl_commands,                /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


#if (NGX_HTTP_SSI)

#define NGX_HTTP_PERL_SSI_SUB  0
#define NGX_HTTP_PERL_SSI_ARG  1


static ngx_http_ssi_param_t  ngx_http_perl_ssi_params[] = {
    { ngx_string("sub"), NGX_HTTP_PERL_SSI_SUB, 1, 0 },
    { ngx_string("arg"), NGX_HTTP_PERL_SSI_ARG, 0, 1 },
    { ngx_null_string, 0, 0, 0 }
};

static ngx_http_ssi_command_t  ngx_http_perl_ssi_command = {
    ngx_string("perl"), ngx_http_perl_ssi, ngx_http_perl_ssi_params, 0, 0, 1
};

#endif


static ngx_str_t  ngx_null_name = ngx_null_string;


static HV  *nginx_stash;

static void
ngx_http_perl_xs_init(pTHX)
{
    newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, __FILE__);

    nginx_stash = gv_stashpv("nginx", TRUE);
}


static ngx_int_t
ngx_http_perl_handler(ngx_http_request_t *r)
{
    /* TODO: Win32 */
    if (r->zero_in_uri) {
        return NGX_HTTP_NOT_FOUND;
    }

    ngx_http_perl_handle_request(r);

    return NGX_DONE;

#if 0
    r->request_body_in_single_buf = 1;
    r->request_body_in_persistent_file = 1;
    r->request_body_delete_incomplete_file = 1;

    if (r->request_body_in_file_only) {
        r->request_body_file_log_level = 0;
    }

    rc = ngx_http_read_client_request_body(r, ngx_http_perl_handle_request);

    if (rc >= NGX_HTTP_SPECIAL_RESPONSE) {
        return rc;
    }

    return NGX_DONE;
#endif
}


void
ngx_http_perl_handle_request(ngx_http_request_t *r)
{
    SV                         *sub;
    ngx_int_t                   rc;
    ngx_str_t                   uri, args, *handler;
    ngx_http_perl_ctx_t        *ctx;
    ngx_http_perl_loc_conf_t   *plcf;
    ngx_http_perl_main_conf_t  *pmcf;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "perl handler");

    ctx = ngx_http_get_module_ctx(r, ngx_http_perl_module);

    if (ctx == NULL) {
        ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_perl_ctx_t));
        if (ctx == NULL) {
            ngx_http_finalize_request(r, NGX_ERROR);
	    return;
        }

        ngx_http_set_ctx(r, ctx, ngx_http_perl_module);
    }

    pmcf = ngx_http_get_module_main_conf(r, ngx_http_perl_module);

    rc = ngx_http_perl_get_interpreter(pmcf, &ctx->perl, r->connection->log);

    if (rc != NGX_OK) {
        ngx_http_finalize_request(r, rc);
        return;
    }

    {

    dTHXa(ctx->perl);

    if (ctx->next == NULL) {
        plcf = ngx_http_get_module_loc_conf(r, ngx_http_perl_module);
        sub = plcf->sub;
        handler = &plcf->handler;

    } else {
        sub = ctx->next;
        handler = &ngx_null_name;
        ctx->next = NULL;
    }

    rc = ngx_http_perl_call_handler(aTHX_ r, sub, NULL, handler, NULL);

    }

    ngx_http_perl_free_interpreter(pmcf, ctx->perl);

    if (rc > 600) {
        rc = NGX_OK;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "perl handler done: %i", rc);

    if (ctx->redirect_uri.len) {
        uri = ctx->redirect_uri;
        args = ctx->redirect_args;

    } else {
        uri.len = 0;
    }

    ctx->filename.data = NULL;
    ctx->redirect_uri.len = 0;

    if (ctx->done || ctx->next) {
        return;
    }

    if (uri.len) {
        ngx_http_internal_redirect(r, &uri, &args);
        return;
    }

    if (rc == NGX_OK || rc == NGX_HTTP_OK) {
        ngx_http_send_special(r, NGX_HTTP_LAST);
        ctx->done = 1;
    }

    ngx_http_finalize_request(r, rc);
}


static ngx_int_t
ngx_http_perl_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    ngx_http_perl_variable_t *pv = (ngx_http_perl_variable_t *) data;

    ngx_int_t                   rc;
    ngx_str_t                   value;
    ngx_http_perl_ctx_t        *ctx;
    ngx_http_perl_main_conf_t  *pmcf;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "perl variable handler");

    ctx = ngx_http_get_module_ctx(r, ngx_http_perl_module);

    if (ctx == NULL) {
        ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_perl_ctx_t));
        if (ctx == NULL) {
            return NGX_ERROR;
        }

        ngx_http_set_ctx(r, ctx, ngx_http_perl_module);
    }

    pmcf = ngx_http_get_module_main_conf(r, ngx_http_perl_module);

    rc = ngx_http_perl_get_interpreter(pmcf, &ctx->perl, r->connection->log);

    if (rc != NGX_OK) {
        return rc;
    }

    value.data = NULL;

    {

    dTHXa(ctx->perl);

    rc = ngx_http_perl_call_handler(aTHX_ r, pv->sub, NULL,
                                    &pv->handler, &value);

    }

    ngx_http_perl_free_interpreter(pmcf, ctx->perl);

    if (value.data) {
        v->len = value.len;
        v->valid = 1;
        v->no_cachable = 0;
        v->not_found = 0;
        v->data = value.data;

    } else {
        v->not_found = 1;
    }

    ctx->filename.data = NULL;
    ctx->redirect_uri.len = 0;

    return rc;
}


#if (NGX_HTTP_SSI)

static ngx_int_t
ngx_http_perl_ssi(ngx_http_request_t *r, ngx_http_ssi_ctx_t *ssi_ctx,
    ngx_str_t **params)
{
    SV                         *sv;
    ngx_int_t                   rc;
    ngx_str_t                  *handler;
    ngx_http_perl_ctx_t        *ctx;
    ngx_http_perl_main_conf_t  *pmcf;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "perl ssi handler");

    pmcf = ngx_http_get_module_main_conf(r, ngx_http_perl_module);

    ctx = ngx_http_get_module_ctx(r, ngx_http_perl_module);

    if (ctx == NULL) {
        ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_perl_ctx_t));
        if (ctx == NULL) {
            return NGX_ERROR;
        }

        ngx_http_set_ctx(r, ctx, ngx_http_perl_module);
    }

    rc = ngx_http_perl_get_interpreter(pmcf, &ctx->perl, r->connection->log);

    if (rc != NGX_OK) {
        return rc;
    }

    ctx->ssi = ssi_ctx;

    handler = params[NGX_HTTP_PERL_SSI_SUB];
    handler->data[handler->len] = '\0';

    {

    dTHXa(ctx->perl);

#if 0

    /* the code is disabled to force the precompiled perl code using only */

    ngx_http_perl_eval_anon_sub(aTHX_ handler, &sv);

    if (sv == &PL_sv_undef) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "eval_pv(\"%V\") failed", handler);
        return NGX_ERROR;
    }

    if (sv == NULL) {
        sv = newSVpvn((char *) handler->data, handler->len);
    }

#endif

    sv = newSVpvn((char *) handler->data, handler->len);

    rc = ngx_http_perl_call_handler(aTHX_ r, sv, &params[NGX_HTTP_PERL_SSI_ARG],
                                    handler, NULL);

    SvREFCNT_dec(sv);

    }

    ngx_http_perl_free_interpreter(pmcf, ctx->perl);

    ctx->filename.data = NULL;
    ctx->redirect_uri.len = 0;
    ctx->ssi = NULL;

    return rc;
}

#endif


static ngx_int_t
ngx_http_perl_get_interpreter(ngx_http_perl_main_conf_t *pmcf,
    PerlInterpreter **perl, ngx_log_t *log)
{
    if (pmcf->interp) {
        pmcf->interp--;

        *perl = pmcf->free_perls[pmcf->interp];

        return NGX_OK;
    }

    if (pmcf->nalloc < pmcf->interp_max) {
        *perl = ngx_http_perl_create_interpreter(pmcf, log);

        if (*perl) {
            return NGX_OK;
        }

        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    ngx_log_error(NGX_LOG_ALERT, log, 0, "no free perl interpreter");

    return NGX_HTTP_SERVICE_UNAVAILABLE;
}


static ngx_inline void
ngx_http_perl_free_interpreter(ngx_http_perl_main_conf_t *pmcf,
    PerlInterpreter *perl)
{
    pmcf->free_perls[pmcf->interp++] = perl;
}


static char *
ngx_http_perl_init_interpreter(ngx_conf_t *cf, ngx_http_perl_main_conf_t *pmcf)
{
#if (NGX_HAVE_PERL_CLONE || NGX_HAVE_PERL_MULTIPLICITY)
    ngx_pool_cleanup_t       *cln;

    cln = ngx_pool_cleanup_add(cf->pool, 0);
    if (cln == NULL) {
        return NGX_CONF_ERROR;
    }

#else
    static PerlInterpreter  *perl;
#endif

#ifdef NGX_PERL_MODULES
    if (pmcf->modules.data == NULL) {
        pmcf->modules.data = NGX_PERL_MODULES;
    }
#endif

    if (pmcf->modules.data) {
        if (ngx_conf_full_name(cf->cycle, &pmcf->modules) != NGX_OK) {
            return NGX_CONF_ERROR;
        }
    }

#if !(NGX_HAVE_PERL_CLONE || NGX_HAVE_PERL_MULTIPLICITY)

    if (perl) {
        if (ngx_http_perl_run_requires(aTHX_ &pmcf->requires, cf->log)
            != NGX_OK)
        {
            return NGX_CONF_ERROR;
        }

        pmcf->perl = perl;

        return NGX_CONF_OK;
    }

#endif

    PERL_SYS_INIT(&ngx_argc, &ngx_argv);

    pmcf->perl = ngx_http_perl_create_interpreter(pmcf, cf->log);

    if (pmcf->perl == NULL) {
        PERL_SYS_TERM();
        return NGX_CONF_ERROR;
    }

#if (NGX_HAVE_PERL_CLONE || NGX_HAVE_PERL_MULTIPLICITY)

    cln->handler = ngx_http_perl_cleanup_perl;
    cln->data = pmcf->perl;

#else

    perl = pmcf->perl;

#endif

    return NGX_CONF_OK;
}


static PerlInterpreter *
ngx_http_perl_create_interpreter(ngx_http_perl_main_conf_t *pmcf,
    ngx_log_t *log)
{
    int                n;
    char              *embedding[6];
    PerlInterpreter   *perl;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, log, 0, "create perl interpreter");

#if (NGX_HAVE_PERL_CLONE)

    if (pmcf->perl) {

        perl = perl_clone(pmcf->perl, CLONEf_KEEP_PTR_TABLE);
        if (perl == NULL) {
            ngx_log_error(NGX_LOG_ALERT, log, 0, "perl_clone() failed");
            return NULL;
        }

        {

        dTHXa(perl);

        ptr_table_free(PL_ptr_table);
        PL_ptr_table = NULL;

        }

        pmcf->nalloc++;

        return perl;
    }

#endif

    perl = perl_alloc();
    if (perl == NULL) {
        ngx_log_error(NGX_LOG_ALERT, log, 0, "perl_alloc() failed");
        return NULL;
    }

    perl_construct(perl);

    {

    dTHXa(perl);

#ifdef PERL_EXIT_DESTRUCT_END
    PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
#endif

    embedding[0] = "";

    if (pmcf->modules.data) {
        embedding[1] = "-I";
        embedding[2] = (char *) pmcf->modules.data;
        n = 3;

    } else {
        n = 1;
    }

    embedding[n++] = "-Mnginx";
    embedding[n++] = "-e";
    embedding[n++] = "0";

    n = perl_parse(perl, ngx_http_perl_xs_init, n, embedding, NULL);

    if (n != 0) {
        ngx_log_error(NGX_LOG_ALERT, log, 0, "perl_parse() failed: %d", n);
        goto fail;
    }

    if (ngx_http_perl_run_requires(aTHX_ &pmcf->requires, log) != NGX_OK) {
        goto fail;
    }

    }

    pmcf->nalloc++;

    return perl;

fail:

    (void) perl_destruct(perl);

    perl_free(perl);

    return NULL;
}


static ngx_int_t
ngx_http_perl_run_requires(pTHX_ ngx_array_t *requires, ngx_log_t *log)
{
    char       **script;
    STRLEN       len;
    ngx_str_t    err;
    ngx_uint_t   i;

    script = requires->elts;
    for (i = 0; i < requires->nelts; i++) {

        require_pv(script[i]);

        if (SvTRUE(ERRSV)) {

            err.data = (u_char *) SvPV(ERRSV, len);
            for (len--; err.data[len] == LF || err.data[len] == CR; len--) {
                /* void */
            }
            err.len = len + 1;

            ngx_log_error(NGX_LOG_EMERG, log, 0,
                          "require_pv(\"%s\") failed: \"%V\"", script[i], &err);

            return NGX_ERROR;
        }
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_perl_call_handler(pTHX_ ngx_http_request_t *r, SV *sub,
    ngx_str_t **args, ngx_str_t *handler, ngx_str_t *rv)
{
    SV          *sv;
    int          n, status;
    char        *line;
    STRLEN       len, n_a;
    ngx_str_t    err;
    ngx_uint_t   i;

    dSP;

    status = 0;

    ENTER;
    SAVETMPS;

    PUSHMARK(sp);

    sv = sv_2mortal(sv_bless(newRV_noinc(newSViv(PTR2IV(r))), nginx_stash));
    XPUSHs(sv);

    if (args) {
        for (i = 0; args[i]; i++) { /* void */ }

        EXTEND(sp, (int) i);

        for (i = 0; args[i]; i++) {
            PUSHs(sv_2mortal(newSVpvn((char *) args[i]->data, args[i]->len)));
        }
    }

    PUTBACK;

    n = call_sv(sub, G_EVAL);

    SPAGAIN;

    if (n) {
        if (rv == NULL) {
            status = POPi;

            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "call_sv: %d", status);

        } else {
            line = SvPVx(POPs, n_a);
            rv->len = n_a;

            rv->data = ngx_palloc(r->pool, n_a);
            if (rv->data == NULL) {
                return NGX_ERROR;
            }

            ngx_memcpy(rv->data, line, n_a);
        }
    }

    PUTBACK;

    FREETMPS;
    LEAVE;

    /* check $@ */

    if (SvTRUE(ERRSV)) {

        err.data = (u_char *) SvPV(ERRSV, len);
        for (len--; err.data[len] == LF || err.data[len] == CR; len--) {
            /* void */
        }
        err.len = len + 1;

        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "call_sv(\"%V\") failed: \"%V\"",
                      handler, &err);

        if (rv) {
            return NGX_ERROR;
        }

        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    if (n != 1) {
        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
                      "call_sv(\"%V\") returned %d results", handler, n);
        status = NGX_OK;
    }

    if (rv) {
        return NGX_OK;
    }

    return (ngx_int_t) status;
}


static void
ngx_http_perl_eval_anon_sub(pTHX_ ngx_str_t *handler, SV **sv)
{
    u_char  *p;

    for (p = handler->data; *p; p++) {
        if (*p != ' ' && *p != '\t' && *p != CR && *p != LF) {
            break;
        }
    }

    if (ngx_strncmp(p, "sub ", 4) == 0 || ngx_strncmp(p, "use ", 4) == 0) {
        *sv = eval_pv((char *) p, FALSE);
        return;
    }

    *sv = NULL;
}


static void *
ngx_http_perl_create_main_conf(ngx_conf_t *cf)
{
    ngx_http_perl_main_conf_t  *pmcf;

    pmcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_perl_main_conf_t));
    if (pmcf == NULL) {
        return NGX_CONF_ERROR;
    }

    pmcf->interp_max = NGX_CONF_UNSET_UINT;

    if (ngx_array_init(&pmcf->requires, cf->pool, 1, sizeof(u_char *))
        != NGX_OK)
    {
        return NULL;
    }

    return pmcf;
}


static char *
ngx_http_perl_init_main_conf(ngx_conf_t *cf, void *conf)
{
    ngx_http_perl_main_conf_t *pmcf = conf;

#if (NGX_HAVE_PERL_CLONE || NGX_HAVE_PERL_MULTIPLICITY)
    ngx_conf_init_uint_value(pmcf->interp_max, 10);
#else
    ngx_conf_init_uint_value(pmcf->interp_max, 1);
#endif

    pmcf->free_perls = ngx_pcalloc(cf->pool,
                                  pmcf->interp_max * sizeof(PerlInterpreter *));
    if (pmcf->free_perls == NULL) {
        return NGX_CONF_ERROR;
    }

    if (pmcf->perl == NULL) {
        if (ngx_http_perl_init_interpreter(cf, pmcf) != NGX_CONF_OK) {
            return NGX_CONF_ERROR;
        }
    }

#if !(NGX_HAVE_PERL_CLONE)
    ngx_http_perl_free_interpreter(pmcf, pmcf->perl);
#endif

    return NGX_CONF_OK;
}


#if (NGX_HAVE_PERL_CLONE || NGX_HAVE_PERL_MULTIPLICITY)

static void
ngx_http_perl_cleanup_perl(void *data)
{
    PerlInterpreter  *perl = data;

    (void) perl_destruct(perl);

    perl_free(perl);

    PERL_SYS_TERM();
}

#endif


static void
ngx_http_perl_cleanup_sv(void *data)
{
    ngx_http_perl_cleanup_t  *cln = data;

    dTHXa(cln->perl);

    SvREFCNT_dec(cln->sv);
}


static ngx_int_t
ngx_http_perl_preconfiguration(ngx_conf_t *cf)
{
#if (NGX_HTTP_SSI)
    ngx_int_t                  rc;
    ngx_http_ssi_main_conf_t  *smcf;

    smcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_ssi_filter_module);

    rc = ngx_hash_add_key(&smcf->commands, &ngx_http_perl_ssi_command.name,
                          &ngx_http_perl_ssi_command, NGX_HASH_READONLY_KEY);

    if (rc != NGX_OK) {
        if (rc == NGX_BUSY) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "conflicting SSI command \"%V\"",
                               &ngx_http_perl_ssi_command.name);
        }

        return NGX_ERROR;
    }
#endif

    return NGX_OK;
}


static void *
ngx_http_perl_create_loc_conf(ngx_conf_t *cf)
{
    ngx_http_perl_loc_conf_t *plcf;

    plcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_perl_loc_conf_t));
    if (plcf == NULL) {
        return NGX_CONF_ERROR;
    }

    /*
     * set by ngx_pcalloc():
     *
     *     plcf->handler = { 0, NULL };
     */

    return plcf;
}


static char *
ngx_http_perl_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_perl_loc_conf_t *prev = parent;
    ngx_http_perl_loc_conf_t *conf = child;

    if (conf->sub == NULL) {
        conf->sub = prev->sub;
        conf->handler = prev->handler;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_perl_require(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_perl_main_conf_t *pmcf = conf;

    u_char     **p;
    ngx_str_t   *value;

    value = cf->args->elts;

    p = ngx_array_push(&pmcf->requires);

    if (p == NULL) {
        return NGX_CONF_ERROR;
    }

    *p = value[1].data;

    return NGX_CONF_OK;
}


static char *
ngx_http_perl(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_perl_loc_conf_t *plcf = conf;

    ngx_str_t                  *value;
    ngx_pool_cleanup_t         *cln;
    ngx_http_perl_cleanup_t    *pcln;
    ngx_http_core_loc_conf_t   *clcf;
    ngx_http_perl_main_conf_t  *pmcf;

    value = cf->args->elts;

    if (plcf->handler.data) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "duplicate perl handler \"%V\"", &value[1]);
        return NGX_CONF_ERROR;
    }

    pmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_perl_module);

    if (pmcf->perl == NULL) {
        if (ngx_http_perl_init_interpreter(cf, pmcf) != NGX_CONF_OK) {
            return NGX_CONF_ERROR;
        }
    }

    cln = ngx_pool_cleanup_add(cf->pool, sizeof(ngx_http_perl_cleanup_t));
    if (cln == NULL) {
        return NGX_CONF_ERROR;
    }

    plcf->handler = value[1];

    {

    dTHXa(pmcf->perl);

    ngx_http_perl_eval_anon_sub(aTHX_ &value[1], &plcf->sub);

    if (plcf->sub == &PL_sv_undef) {
        ngx_conf_log_error(NGX_LOG_ERR, cf, 0,
                           "eval_pv(\"%V\") failed", &value[1]);
        return NGX_CONF_ERROR;
    }

    if (plcf->sub == NULL) {
        plcf->sub = newSVpvn((char *) value[1].data, value[1].len);
    }

    }

    cln->handler = ngx_http_perl_cleanup_sv;
    pcln = cln->data;
    pcln->sv = plcf->sub;
    pcln->perl = pmcf->perl;

    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
    clcf->handler = ngx_http_perl_handler;

    return NGX_CONF_OK;
}


static char *
ngx_http_perl_set(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_int_t                   index;
    ngx_str_t                  *value;
    ngx_pool_cleanup_t         *cln;
    ngx_http_variable_t        *v;
    ngx_http_perl_cleanup_t    *pcln;
    ngx_http_perl_variable_t   *pv;
    ngx_http_perl_main_conf_t  *pmcf;

    value = cf->args->elts;

    if (value[1].data[0] != '$') {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid variable name \"%V\"", &value[1]);
        return NGX_CONF_ERROR;
    }

    value[1].len--;
    value[1].data++;

    v = ngx_http_add_variable(cf, &value[1], NGX_HTTP_VAR_CHANGABLE);
    if (v == NULL) {
        return NGX_CONF_ERROR;
    }

    pv = ngx_palloc(cf->pool, sizeof(ngx_http_perl_variable_t));
    if (pv == NULL) {
        return NGX_CONF_ERROR;
    }

    index = ngx_http_get_variable_index(cf, &value[1]);
    if (index == NGX_ERROR) {
        return NGX_CONF_ERROR;
    }

    pmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_perl_module);

    if (pmcf->perl == NULL) {
        if (ngx_http_perl_init_interpreter(cf, pmcf) != NGX_CONF_OK) {
            return NGX_CONF_ERROR;
        }
    }

    cln = ngx_pool_cleanup_add(cf->pool, sizeof(ngx_http_perl_cleanup_t));
    if (cln == NULL) {
        return NGX_CONF_ERROR;
    }

    pv->handler = value[2];

    {

    dTHXa(pmcf->perl);

    ngx_http_perl_eval_anon_sub(aTHX_ &value[2], &pv->sub);

    if (pv->sub == &PL_sv_undef) {
        ngx_conf_log_error(NGX_LOG_ERR, cf, 0,
                           "eval_pv(\"%V\") failed", &value[2]);
        return NGX_CONF_ERROR;
    }

    if (pv->sub == NULL) {
        pv->sub = newSVpvn((char *) value[2].data, value[2].len);
    }

    }

    cln->handler = ngx_http_perl_cleanup_sv;
    pcln = cln->data;
    pcln->sv = pv->sub;
    pcln->perl = pmcf->perl;

    v->get_handler = ngx_http_perl_variable;
    v->data = (uintptr_t) pv;

    return NGX_CONF_OK;
}


static char *
ngx_http_perl_interp_max_unsupported(ngx_conf_t *cf, void *post, void *data)
{
#if (NGX_HAVE_PERL_CLONE || NGX_HAVE_PERL_MULTIPLICITY)

    return NGX_CONF_OK;

#else

    return "to use perl_interp_max you have to build perl with "
           "-Dusemultiplicity or -Dusethreads options";

#endif
}