view src/http/modules/perl/nginx.xs @ 7525:575480d3fd01

Perl: propagate errors. When an error happens, the ctx->error bit is now set, and croak() is called to terminate further processing. The ctx->error bit is checked in ngx_http_perl_call_handler() to cancel further processing, and is also checked in various output functions - to make sure these won't be called if croak() was handled by an eval{} in perl code. In particular, this ensures that output chain won't be called after errors, as filters might not expect this to happen. This fixes some segmentation faults under low memory conditions. Also this stops request processing after filter finalization or request body reading errors. For cases where an HTTP error status can be additionally returned (for example, 416 (Requested Range Not Satisfiable) from the range filter), the ctx->status field is also added.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 12 Jul 2019 13:56:21 +0300
parents deebe988cbd7
children 8125552a10ca
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#define PERL_NO_GET_CONTEXT

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

#include "XSUB.h"


#define ngx_http_perl_set_request(r, ctx)                                     \
                                                                              \
    ctx = INT2PTR(ngx_http_perl_ctx_t *, SvIV((SV *) SvRV(ST(0))));           \
    r = ctx->request


#define ngx_http_perl_set_targ(p, len)                                        \
                                                                              \
    SvUPGRADE(TARG, SVt_PV);                                                  \
    SvPOK_on(TARG);                                                           \
    sv_setpvn(TARG, (char *) p, len)


static ngx_int_t
ngx_http_perl_sv2str(pTHX_ ngx_http_request_t *r, ngx_str_t *s, SV *sv)
{
    u_char  *p;
    STRLEN   len;

    if (SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PV) {
        sv = SvRV(sv);
    }

    p = (u_char *) SvPV(sv, len);

    s->len = len;

    if (SvREADONLY(sv) && SvPOK(sv)) {
        s->data = p;

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "perl sv2str: %08XD \"%V\"", sv->sv_flags, s);

        return NGX_OK;
    }

    s->data = ngx_pnalloc(r->pool, len);
    if (s->data == NULL) {
        return NGX_ERROR;
    }

    ngx_memcpy(s->data, p, len);

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "perl sv2str: %08XD \"%V\"", sv->sv_flags, s);

    return NGX_OK;
}


static ngx_int_t
ngx_http_perl_output(ngx_http_request_t *r, ngx_http_perl_ctx_t *ctx,
    ngx_buf_t *b)
{
    ngx_chain_t   out;
#if (NGX_HTTP_SSI)
    ngx_chain_t  *cl;

    if (ctx->ssi) {
        cl = ngx_alloc_chain_link(r->pool);
        if (cl == NULL) {
            return NGX_ERROR;
        }

        cl->buf = b;
        cl->next = NULL;
        *ctx->ssi->last_out = cl;
        ctx->ssi->last_out = &cl->next;

        return NGX_OK;
    }
#endif

    out.buf = b;
    out.next = NULL;

    return ngx_http_output_filter(r, &out);
}


MODULE = nginx    PACKAGE = nginx


PROTOTYPES: DISABLE


void
status(r, code)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);

    r->headers_out.status = SvIV(ST(1));

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

    XSRETURN_UNDEF;


void
send_http_header(r, ...)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    SV                   *sv;
    ngx_int_t             rc;

    ngx_http_perl_set_request(r, ctx);

    if (ctx->error) {
        croak("send_http_header(): called after error");
    }

    if (r->headers_out.status == 0) {
        r->headers_out.status = NGX_HTTP_OK;
    }

    if (items != 1) {
        sv = ST(1);

        if (ngx_http_perl_sv2str(aTHX_ r, &r->headers_out.content_type, sv)
            != NGX_OK)
        {
            XSRETURN_EMPTY;
        }

        r->headers_out.content_type_len = r->headers_out.content_type.len;

    } else {
        if (ngx_http_set_content_type(r) != NGX_OK) {
            XSRETURN_EMPTY;
        }
    }

    r->disable_not_modified = 1;

    rc = ngx_http_send_header(r);

    if (rc == NGX_ERROR || rc > NGX_OK) {
        ctx->error = 1;
        ctx->status = rc;
        croak("ngx_http_send_header() failed");
    }


void
header_only(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);

    sv_upgrade(TARG, SVt_IV);
    sv_setiv(TARG, r->header_only);

    ST(0) = TARG;


void
uri(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);
    ngx_http_perl_set_targ(r->uri.data, r->uri.len);

    ST(0) = TARG;


void
args(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);
    ngx_http_perl_set_targ(r->args.data, r->args.len);

    ST(0) = TARG;


void
request_method(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);
    ngx_http_perl_set_targ(r->method_name.data, r->method_name.len);

    ST(0) = TARG;


void
remote_addr(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);
    ngx_http_perl_set_targ(r->connection->addr_text.data,
                           r->connection->addr_text.len);

    ST(0) = TARG;


void
header_in(r, key)
    CODE:

    dXSTARG;
    ngx_http_request_t         *r;
    ngx_http_perl_ctx_t        *ctx;
    SV                         *key;
    u_char                     *p, *lowcase_key, *value, sep;
    STRLEN                      len;
    ssize_t                     size;
    ngx_uint_t                  i, n, hash;
    ngx_array_t                *a;
    ngx_list_part_t            *part;
    ngx_table_elt_t            *h, **ph;
    ngx_http_header_t          *hh;
    ngx_http_core_main_conf_t  *cmcf;

    ngx_http_perl_set_request(r, ctx);

    key = ST(1);

    if (SvROK(key) && SvTYPE(SvRV(key)) == SVt_PV) {
        key = SvRV(key);
    }

    p = (u_char *) SvPV(key, len);

    /* look up hashed headers */

    lowcase_key = ngx_pnalloc(r->pool, len);
    if (lowcase_key == NULL) {
        XSRETURN_UNDEF;
    }

    hash = ngx_hash_strlow(lowcase_key, p, len);

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);

    hh = ngx_hash_find(&cmcf->headers_in_hash, hash, lowcase_key, len);

    if (hh) {

        if (hh->offset == offsetof(ngx_http_headers_in_t, cookies)) {
            sep = ';';
            goto multi;
        }
#if (NGX_HTTP_X_FORWARDED_FOR)
        if (hh->offset == offsetof(ngx_http_headers_in_t, x_forwarded_for)) {
            sep = ',';
            goto multi;
        }
#endif

        ph = (ngx_table_elt_t **) ((char *) &r->headers_in + hh->offset);

        if (*ph) {
            ngx_http_perl_set_targ((*ph)->value.data, (*ph)->value.len);

            goto done;
        }

        XSRETURN_UNDEF;

    multi:

        /* Cookie, X-Forwarded-For */

        a = (ngx_array_t *) ((char *) &r->headers_in + hh->offset);

        n = a->nelts;

        if (n == 0) {
            XSRETURN_UNDEF;
        }

        ph = a->elts;

        if (n == 1) {
            ngx_http_perl_set_targ((*ph)->value.data, (*ph)->value.len);

            goto done;
        }

        size = - (ssize_t) (sizeof("; ") - 1);

        for (i = 0; i < n; i++) {
            size += ph[i]->value.len + sizeof("; ") - 1;
        }

        value = ngx_pnalloc(r->pool, size);
        if (value == NULL) {
            XSRETURN_UNDEF;
        }

        p = value;

        for (i = 0; /* void */ ; i++) {
            p = ngx_copy(p, ph[i]->value.data, ph[i]->value.len);

            if (i == n - 1) {
                break;
            }

            *p++ = sep; *p++ = ' ';
        }

        ngx_http_perl_set_targ(value, size);

        goto done;
    }

    /* iterate over all headers */

    part = &r->headers_in.headers.part;
    h = part->elts;

    for (i = 0; /* void */ ; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }

            part = part->next;
            h = part->elts;
            i = 0;
        }

        if (len != h[i].key.len
            || ngx_strcasecmp(p, h[i].key.data) != 0)
        {
            continue;
        }

        ngx_http_perl_set_targ(h[i].value.data, h[i].value.len);

        goto done;
    }

    XSRETURN_UNDEF;

    done:

    ST(0) = TARG;


void
has_request_body(r, next)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    ngx_int_t             rc;

    ngx_http_perl_set_request(r, ctx);

    if (r->headers_in.content_length_n <= 0 && !r->headers_in.chunked) {
        XSRETURN_UNDEF;
    }

    ctx->next = SvRV(ST(1));

    r->request_body_in_single_buf = 1;
    r->request_body_in_persistent_file = 1;
    r->request_body_in_clean_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) {
        ctx->error = 1;
        ctx->status = rc;
        ctx->next = NULL;
        croak("ngx_http_read_client_request_body() failed");
    }

    sv_upgrade(TARG, SVt_IV);
    sv_setiv(TARG, 1);

    ST(0) = TARG;


void
request_body(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    u_char               *p, *data;
    size_t                len;
    ngx_buf_t            *buf;
    ngx_chain_t          *cl;

    ngx_http_perl_set_request(r, ctx);

    if (r->request_body == NULL
        || r->request_body->temp_file
        || r->request_body->bufs == NULL)
    {
        XSRETURN_UNDEF;
    }

    cl = r->request_body->bufs;
    buf = cl->buf;

    if (cl->next == NULL) {
        len = buf->last - buf->pos;
        data = buf->pos;
        goto done;
    }

    len = buf->last - buf->pos;
    cl = cl->next;

    for ( /* void */ ; cl; cl = cl->next) {
        buf = cl->buf;
        len += buf->last - buf->pos;
    }

    p = ngx_pnalloc(r->pool, len);
    if (p == NULL) {
        XSRETURN_UNDEF;
    }

    data = p;
    cl = r->request_body->bufs;

    for ( /* void */ ; cl; cl = cl->next) {
        buf = cl->buf;
        p = ngx_cpymem(p, buf->pos, buf->last - buf->pos);
    }

    done:

    if (len == 0) {
        XSRETURN_UNDEF;
    }

    ngx_http_perl_set_targ(data, len);

    ST(0) = TARG;


void
request_body_file(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);

    if (r->request_body == NULL || r->request_body->temp_file == NULL) {
        XSRETURN_UNDEF;
    }

    ngx_http_perl_set_targ(r->request_body->temp_file->file.name.data,
                           r->request_body->temp_file->file.name.len);

    ST(0) = TARG;


void
discard_request_body(r)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    ngx_int_t             rc;

    ngx_http_perl_set_request(r, ctx);

    rc = ngx_http_discard_request_body(r);

    if (rc != NGX_OK) {
        ctx->error = 1;
        ctx->status = rc;
        croak("ngx_http_discard_request_body() failed");
    }


void
header_out(r, key, value)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    SV                   *key;
    SV                   *value;
    ngx_table_elt_t      *header;

    ngx_http_perl_set_request(r, ctx);

    if (ctx->error) {
        croak("header_out(): called after error");
    }

    key = ST(1);
    value = ST(2);

    header = ngx_list_push(&r->headers_out.headers);
    if (header == NULL) {
        XSRETURN_EMPTY;
    }

    header->hash = 1;

    if (ngx_http_perl_sv2str(aTHX_ r, &header->key, key) != NGX_OK) {
        header->hash = 0;
        XSRETURN_EMPTY;
    }

    if (ngx_http_perl_sv2str(aTHX_ r, &header->value, value) != NGX_OK) {
        header->hash = 0;
        XSRETURN_EMPTY;
    }

    if (header->key.len == sizeof("Content-Length") - 1
        && ngx_strncasecmp(header->key.data, (u_char *) "Content-Length",
                           sizeof("Content-Length") - 1) == 0)
    {
        r->headers_out.content_length_n = (off_t) SvIV(value);
        r->headers_out.content_length = header;
    }

    if (header->key.len == sizeof("Content-Encoding") - 1
        && ngx_strncasecmp(header->key.data, (u_char *) "Content-Encoding",
                           sizeof("Content-Encoding") - 1) == 0)
    {
        r->headers_out.content_encoding = header;
    }


void
filename(r)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    size_t                root;

    ngx_http_perl_set_request(r, ctx);

    if (ctx->filename.data) {
        goto done;
    }

    if (ngx_http_map_uri_to_path(r, &ctx->filename, &root, 0) == NULL) {
        XSRETURN_UNDEF;
    }

    ctx->filename.len--;
    sv_setpv(PL_statname, (char *) ctx->filename.data);

    done:

    ngx_http_perl_set_targ(ctx->filename.data, ctx->filename.len);

    ST(0) = TARG;


void
print(r, ...)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    SV                   *sv;
    int                   i;
    u_char               *p;
    size_t                size;
    STRLEN                len;
    ngx_int_t             rc;
    ngx_buf_t            *b;

    ngx_http_perl_set_request(r, ctx);

    if (ctx->error) {
        croak("print(): called after error");
    }

    if (items == 2) {

        /*
         * do zero copy for prolate single read-only SV:
         *     $r->print("some text\n");
         */

        sv = ST(1);

        if (SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PV) {
            sv = SvRV(sv);
        }

        if (SvREADONLY(sv) && SvPOK(sv)) {

            p = (u_char *) SvPV(sv, len);

            if (len == 0) {
                XSRETURN_EMPTY;
            }

            b = ngx_calloc_buf(r->pool);
            if (b == NULL) {
                XSRETURN_EMPTY;
            }

            b->memory = 1;
            b->pos = p;
            b->last = p + len;
            b->start = p;
            b->end = b->last;

            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "$r->print: read-only SV: %z", len);

            goto out;
        }
    }

    size = 0;

    for (i = 1; i < items; i++) {

        sv = ST(i);

        if (SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PV) {
            sv = SvRV(sv);
        }

        (void) SvPV(sv, len);

        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "$r->print: copy SV: %z", len);

        size += len;
    }

    if (size == 0) {
        XSRETURN_EMPTY;
    }

    b = ngx_create_temp_buf(r->pool, size);
    if (b == NULL) {
        XSRETURN_EMPTY;
    }

    for (i = 1; i < items; i++) {
        sv = ST(i);

        if (SvROK(sv) && SvTYPE(SvRV(sv)) == SVt_PV) {
            sv = SvRV(sv);
        }

        p = (u_char *) SvPV(sv, len);
        b->last = ngx_cpymem(b->last, p, len);
    }

    out:

    rc = ngx_http_perl_output(r, ctx, b);

    if (rc == NGX_ERROR) {
        ctx->error = 1;
        croak("ngx_http_perl_output() failed");
    }


void
sendfile(r, filename, offset = -1, bytes = 0)
    CODE:

    ngx_http_request_t        *r;
    ngx_http_perl_ctx_t       *ctx;
    char                      *filename;
    off_t                      offset;
    size_t                     bytes;
    ngx_int_t                  rc;
    ngx_str_t                  path;
    ngx_buf_t                 *b;
    ngx_open_file_info_t       of;
    ngx_http_core_loc_conf_t  *clcf;

    ngx_http_perl_set_request(r, ctx);

    if (ctx->error) {
        croak("sendfile(): called after error");
    }

    filename = SvPV_nolen(ST(1));

    if (filename == NULL) {
        croak("sendfile(): NULL filename");
    }

    offset = items < 3 ? -1 : SvIV(ST(2));
    bytes = items < 4 ? 0 : SvIV(ST(3));

    b = ngx_calloc_buf(r->pool);
    if (b == NULL) {
        XSRETURN_EMPTY;
    }

    b->file = ngx_pcalloc(r->pool, sizeof(ngx_file_t));
    if (b->file == NULL) {
        XSRETURN_EMPTY;
    }

    path.len = ngx_strlen(filename);

    path.data = ngx_pnalloc(r->pool, path.len + 1);
    if (path.data == NULL) {
        XSRETURN_EMPTY;
    }

    (void) ngx_cpystrn(path.data, (u_char *) filename, path.len + 1);

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

    ngx_memzero(&of, sizeof(ngx_open_file_info_t));

    of.read_ahead = clcf->read_ahead;
    of.directio = clcf->directio;
    of.valid = clcf->open_file_cache_valid;
    of.min_uses = clcf->open_file_cache_min_uses;
    of.errors = clcf->open_file_cache_errors;
    of.events = clcf->open_file_cache_events;

    if (ngx_http_set_disable_symlinks(r, clcf, &path, &of) != NGX_OK) {
        XSRETURN_EMPTY;
    }

    if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool)
        != NGX_OK)
    {
        if (of.err == 0) {
            XSRETURN_EMPTY;
        }

        ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno,
                      "%s \"%s\" failed", of.failed, filename);
        XSRETURN_EMPTY;
    }

    if (offset == -1) {
        offset = 0;
    }

    if (bytes == 0) {
        bytes = of.size - offset;
    }

    b->in_file = 1;

    b->file_pos = offset;
    b->file_last = offset + bytes;

    b->file->fd = of.fd;
    b->file->log = r->connection->log;
    b->file->directio = of.is_directio;

    rc = ngx_http_perl_output(r, ctx, b);

    if (rc == NGX_ERROR) {
        ctx->error = 1;
        croak("ngx_http_perl_output() failed");
    }


void
flush(r)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    ngx_int_t             rc;
    ngx_buf_t            *b;

    ngx_http_perl_set_request(r, ctx);

    if (ctx->error) {
        croak("flush(): called after error");
    }

    b = ngx_calloc_buf(r->pool);
    if (b == NULL) {
        XSRETURN_EMPTY;
    }

    b->flush = 1;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "$r->flush");

    rc = ngx_http_perl_output(r, ctx, b);

    if (rc == NGX_ERROR) {
        ctx->error = 1;
        croak("ngx_http_perl_output() failed");
    }

    XSRETURN_EMPTY;


void
internal_redirect(r, uri)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    SV                   *uri;
    ngx_uint_t            i;

    ngx_http_perl_set_request(r, ctx);

    uri = ST(1);

    if (ngx_http_perl_sv2str(aTHX_ r, &ctx->redirect_uri, uri) != NGX_OK) {
        XSRETURN_EMPTY;
    }

    for (i = 0; i < ctx->redirect_uri.len; i++) {
        if (ctx->redirect_uri.data[i] == '?') {

            ctx->redirect_args.len = ctx->redirect_uri.len - (i + 1);
            ctx->redirect_args.data = &ctx->redirect_uri.data[i + 1];
            ctx->redirect_uri.len = i;

            XSRETURN_EMPTY;
        }
    }


void
allow_ranges(r)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;

    ngx_http_perl_set_request(r, ctx);

    r->allow_ranges = 1;


void
unescape(r, text, type = 0)
    CODE:

    dXSTARG;
    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    SV                   *text;
    int                   type;
    u_char               *p, *dst, *src;
    STRLEN                len;

    ngx_http_perl_set_request(r, ctx);

    text = ST(1);

    src = (u_char *) SvPV(text, len);

    p = ngx_pnalloc(r->pool, len + 1);
    if (p == NULL) {
        XSRETURN_UNDEF;
    }

    dst = p;

    type = items < 3 ? 0 : SvIV(ST(2));

    ngx_unescape_uri(&dst, &src, len, (ngx_uint_t) type);
    *dst = '\0';

    ngx_http_perl_set_targ(p, dst - p);

    ST(0) = TARG;


void
variable(r, name, value = NULL)
    CODE:

    dXSTARG;
    ngx_http_request_t         *r;
    ngx_http_perl_ctx_t        *ctx;
    SV                         *name, *value;
    u_char                     *p, *lowcase;
    STRLEN                      len;
    ngx_str_t                   var, val;
    ngx_uint_t                  i, hash;
    ngx_http_perl_var_t        *v;
    ngx_http_variable_value_t  *vv;

    ngx_http_perl_set_request(r, ctx);

    name = ST(1);

    if (SvROK(name) && SvTYPE(SvRV(name)) == SVt_PV) {
        name = SvRV(name);
    }

    if (items == 2) {
        value = NULL;

    } else {
        value = ST(2);

        if (SvROK(value) && SvTYPE(SvRV(value)) == SVt_PV) {
            value = SvRV(value);
        }

        if (ngx_http_perl_sv2str(aTHX_ r, &val, value) != NGX_OK) {
            XSRETURN_UNDEF;
        }
    }

    p = (u_char *) SvPV(name, len);

    lowcase = ngx_pnalloc(r->pool, len);
    if (lowcase == NULL) {
        XSRETURN_UNDEF;
    }

    hash = ngx_hash_strlow(lowcase, p, len);

    var.len = len;
    var.data = lowcase;
#if (NGX_DEBUG)

    if (value) {
        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "perl variable: \"%V\"=\"%V\"", &var, &val);
    } else {
        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "perl variable: \"%V\"", &var);
    }
#endif

    vv = ngx_http_get_variable(r, &var, hash);
    if (vv == NULL) {
        XSRETURN_UNDEF;
    }

    if (vv->not_found) {

        if (ctx->variables) {

            v = ctx->variables->elts;
            for (i = 0; i < ctx->variables->nelts; i++) {

                if (hash != v[i].hash
                    || len != v[i].name.len
                    || ngx_strncmp(lowcase, v[i].name.data, len) != 0)
                {
                    continue;
                }

                if (value) {
                    v[i].value = val;
                    XSRETURN_UNDEF;
                }

                ngx_http_perl_set_targ(v[i].value.data, v[i].value.len);

                goto done;
            }
        }

        if (value) {
            if (ctx->variables == NULL) {
                ctx->variables = ngx_array_create(r->pool, 1,
                                                  sizeof(ngx_http_perl_var_t));
                if (ctx->variables == NULL) {
                    XSRETURN_UNDEF;
                }
            }

            v = ngx_array_push(ctx->variables);
            if (v == NULL) {
                XSRETURN_UNDEF;
            }

            v->hash = hash;
            v->name.len = len;
            v->name.data = lowcase;
            v->value = val;

            XSRETURN_UNDEF;
        }

        XSRETURN_UNDEF;
    }

    if (value) {
        vv->len = val.len;
        vv->valid = 1;
        vv->no_cacheable = 0;
        vv->not_found = 0;
        vv->data = val.data;

        XSRETURN_UNDEF;
    }

    ngx_http_perl_set_targ(vv->data, vv->len);

    done:

    ST(0) = TARG;


void
sleep(r, sleep, next)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    ngx_msec_t            sleep;

    ngx_http_perl_set_request(r, ctx);

    sleep = (ngx_msec_t) SvIV(ST(1));

    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "perl sleep: %M", sleep);

    ctx->next = SvRV(ST(2));

    r->connection->write->delayed = 1;
    ngx_add_timer(r->connection->write, sleep);

    r->write_event_handler = ngx_http_perl_sleep_handler;
    r->main->count++;


void
log_error(r, err, msg)
    CODE:

    ngx_http_request_t   *r;
    ngx_http_perl_ctx_t  *ctx;
    SV                   *err, *msg;
    u_char               *p;
    STRLEN                len;
    ngx_err_t             e;

    ngx_http_perl_set_request(r, ctx);

    err = ST(1);

    if (SvROK(err) && SvTYPE(SvRV(err)) == SVt_PV) {
        err = SvRV(err);
    }

    e = SvIV(err);

    msg = ST(2);

    if (SvROK(msg) && SvTYPE(SvRV(msg)) == SVt_PV) {
        msg = SvRV(msg);
    }

    p = (u_char *) SvPV(msg, len);

    ngx_log_error(NGX_LOG_ERR, r->connection->log, e, "perl: %s", p);