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view src/http/modules/ngx_http_rewrite_module.c @ 4247:b79dbadb3d5e stable-1.0

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Merging r4147, r4148, r4149, r4150, r4207: Fixes of combination of error_page and return directives: *) Fix for incorrect 201 replies from dav module. Replies with 201 code contain body, and we should clearly indicate it's empty if it's empty. Before 0.8.32 chunked was explicitly disabled for 201 replies and as a result empty body was indicated by connection close (not perfect, but worked). Since 0.8.32 chunked is enabled, and this causes incorrect responses from dav module when HTTP/1.1 is used: with "Transfer-Encoding: chunked" but no chunks at all. Fix is to actually return empty body in special response handler instead of abusing r->header_only flag. See here for initial report: http://mailman.nginx.org/pipermail/nginx-ru/2010-October/037535.html *) Fix for double content when return is used in error_page handler. Test case: location / { error_page 405 /nope; return 405; } location /nope { return 200; } This is expected to return 405 with empty body, but in 0.8.42+ will return builtin 405 error page as well (though not counted in Content-Length, thus breaking protocol). Fix is to use status provided by rewrite script execution in case it's less than NGX_HTTP_BAD_REQUEST even if r->error_status set. This check is in line with one in ngx_http_script_return_code(). Note that this patch also changes behaviour for "return 302 ..." and "rewrite ... redirect" used as error handler. E.g. location / { error_page 405 /redirect; return 405; } location /redirect { rewrite ^ http://example.com/; } will actually return redirect to "http://example.com/" instead of builtin 405 error page with meaningless Location header. This looks like correct change and it's in line with what happens on e.g. directory redirects in error handlers. *) Fix for "return 202" not discarding body. Big POST (not fully preread) to a location / { return 202; } resulted in incorrect behaviour due to "return" code path not calling ngx_http_discard_request_body(). The same applies to all "return" used with 2xx/3xx codes except 201 and 204, and to all "return ... text" uses. Fix is to add ngx_http_discard_request_body() call to ngx_http_send_response() function where it looks appropriate. Discard body call from emtpy gif module removed as it's now redundant. Reported by Pyry Hakulinen, see http://mailman.nginx.org/pipermail/nginx/2011-August/028503.html *) Incorrect special case for "return 204" removed. The special case in question leads to replies without body in configuration like location / { error_page 404 /zero; return 404; } location /zero { return 204; } while replies with empty body are expected per protocol specs. Correct one will look like if (status == NGX_HTTP_NO_CONTENT) { rc = ngx_http_send_header(r); if (rc == NGX_ERROR || r->header_only) { return rc; } return ngx_http_send_special(r, NGX_HTTP_LAST); } though it looks like it's better to drop this special case at all. *) Clear old Location header (if any) while adding a new one. This prevents incorrect behaviour when another redirect is issued within error_page 302 handler.
author Igor Sysoev <igor@sysoev.ru>
date Tue, 01 Nov 2011 13:45:33 +0000
parents 187783310b65
children 470462cfa31b
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


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


typedef struct {
    ngx_array_t  *codes;        /* uintptr_t */

    ngx_uint_t    stack_size;

    ngx_flag_t    log;
    ngx_flag_t    uninitialized_variable_warn;
} ngx_http_rewrite_loc_conf_t;


static void *ngx_http_rewrite_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_rewrite_merge_loc_conf(ngx_conf_t *cf,
    void *parent, void *child);
static ngx_int_t ngx_http_rewrite_init(ngx_conf_t *cf);
static char *ngx_http_rewrite(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static char *ngx_http_rewrite_return(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_rewrite_break(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_rewrite_if(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char * ngx_http_rewrite_if_condition(ngx_conf_t *cf,
    ngx_http_rewrite_loc_conf_t *lcf);
static char *ngx_http_rewrite_variable(ngx_conf_t *cf,
    ngx_http_rewrite_loc_conf_t *lcf, ngx_str_t *value);
static char *ngx_http_rewrite_set(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char * ngx_http_rewrite_value(ngx_conf_t *cf,
    ngx_http_rewrite_loc_conf_t *lcf, ngx_str_t *value);


static ngx_command_t  ngx_http_rewrite_commands[] = {

    { ngx_string("rewrite"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_SIF_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
                       |NGX_CONF_TAKE23,
      ngx_http_rewrite,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("return"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_SIF_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
                       |NGX_CONF_TAKE12,
      ngx_http_rewrite_return,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("break"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_SIF_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
                       |NGX_CONF_NOARGS,
      ngx_http_rewrite_break,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("if"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_BLOCK|NGX_CONF_1MORE,
      ngx_http_rewrite_if,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("set"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_SIF_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
                       |NGX_CONF_TAKE2,
      ngx_http_rewrite_set,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("rewrite_log"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_SIF_CONF|NGX_HTTP_LOC_CONF
                        |NGX_HTTP_LIF_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_rewrite_loc_conf_t, log),
      NULL },

    { ngx_string("uninitialized_variable_warn"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_SIF_CONF|NGX_HTTP_LOC_CONF
                        |NGX_HTTP_LIF_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_rewrite_loc_conf_t, uninitialized_variable_warn),
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_rewrite_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_rewrite_init,                 /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

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

    ngx_http_rewrite_create_loc_conf,      /* create location configration */
    ngx_http_rewrite_merge_loc_conf        /* merge location configration */
};


ngx_module_t  ngx_http_rewrite_module = {
    NGX_MODULE_V1,
    &ngx_http_rewrite_module_ctx,          /* module context */
    ngx_http_rewrite_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
};


static ngx_int_t
ngx_http_rewrite_handler(ngx_http_request_t *r)
{
    ngx_http_script_code_pt       code;
    ngx_http_script_engine_t     *e;
    ngx_http_rewrite_loc_conf_t  *rlcf;

    rlcf = ngx_http_get_module_loc_conf(r, ngx_http_rewrite_module);

    if (rlcf->codes == NULL) {
        return NGX_DECLINED;
    }

    e = ngx_pcalloc(r->pool, sizeof(ngx_http_script_engine_t));
    if (e == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    e->sp = ngx_pcalloc(r->pool,
                        rlcf->stack_size * sizeof(ngx_http_variable_value_t));
    if (e->sp == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    e->ip = rlcf->codes->elts;
    e->request = r;
    e->quote = 1;
    e->log = rlcf->log;
    e->status = NGX_DECLINED;

    while (*(uintptr_t *) e->ip) {
        code = *(ngx_http_script_code_pt *) e->ip;
        code(e);
    }

    if (e->status < NGX_HTTP_BAD_REQUEST) {
        return e->status;
    }

    if (r->err_status == 0) {
        return e->status;
    }

    return r->err_status;
}


static ngx_int_t
ngx_http_rewrite_var(ngx_http_request_t *r, ngx_http_variable_value_t *v,
    uintptr_t data)
{
    ngx_http_variable_t          *var;
    ngx_http_core_main_conf_t    *cmcf;
    ngx_http_rewrite_loc_conf_t  *rlcf;

    rlcf = ngx_http_get_module_loc_conf(r, ngx_http_rewrite_module);

    if (rlcf->uninitialized_variable_warn == 0) {
        *v = ngx_http_variable_null_value;
        return NGX_OK;
    }

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);

    var = cmcf->variables.elts;

    /*
     * the ngx_http_rewrite_module sets variables directly in r->variables,
     * and they should be handled by ngx_http_get_indexed_variable(),
     * so the handler is called only if the variable is not initialized
     */

    ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
                  "using uninitialized \"%V\" variable", &var[data].name);

    *v = ngx_http_variable_null_value;

    return NGX_OK;
}


static void *
ngx_http_rewrite_create_loc_conf(ngx_conf_t *cf)
{
    ngx_http_rewrite_loc_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_rewrite_loc_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    conf->stack_size = NGX_CONF_UNSET_UINT;
    conf->log = NGX_CONF_UNSET;
    conf->uninitialized_variable_warn = NGX_CONF_UNSET;

    return conf;
}


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

    uintptr_t  *code;

    ngx_conf_merge_value(conf->log, prev->log, 0);
    ngx_conf_merge_value(conf->uninitialized_variable_warn,
                         prev->uninitialized_variable_warn, 1);
    ngx_conf_merge_uint_value(conf->stack_size, prev->stack_size, 10);

    if (conf->codes == NULL) {
        return NGX_CONF_OK;
    }

    if (conf->codes == prev->codes) {
        return NGX_CONF_OK;
    }

    code = ngx_array_push_n(conf->codes, sizeof(uintptr_t));
    if (code == NULL) {
        return NGX_CONF_ERROR;
    }

    *code = (uintptr_t) NULL;

    return NGX_CONF_OK;
}


static ngx_int_t
ngx_http_rewrite_init(ngx_conf_t *cf)
{
    ngx_http_handler_pt        *h;
    ngx_http_core_main_conf_t  *cmcf;

    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

    h = ngx_array_push(&cmcf->phases[NGX_HTTP_SERVER_REWRITE_PHASE].handlers);
    if (h == NULL) {
        return NGX_ERROR;
    }

    *h = ngx_http_rewrite_handler;

    h = ngx_array_push(&cmcf->phases[NGX_HTTP_REWRITE_PHASE].handlers);
    if (h == NULL) {
        return NGX_ERROR;
    }

    *h = ngx_http_rewrite_handler;

    return NGX_OK;
}


static char *
ngx_http_rewrite(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_rewrite_loc_conf_t  *lcf = conf;

    ngx_str_t                         *value;
    ngx_uint_t                         last;
    ngx_regex_compile_t                rc;
    ngx_http_script_code_pt           *code;
    ngx_http_script_compile_t          sc;
    ngx_http_script_regex_code_t      *regex;
    ngx_http_script_regex_end_code_t  *regex_end;
    u_char                             errstr[NGX_MAX_CONF_ERRSTR];

    regex = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                       sizeof(ngx_http_script_regex_code_t));
    if (regex == NULL) {
        return NGX_CONF_ERROR;
    }

    ngx_memzero(regex, sizeof(ngx_http_script_regex_code_t));

    value = cf->args->elts;

    ngx_memzero(&rc, sizeof(ngx_regex_compile_t));

    rc.pattern = value[1];
    rc.err.len = NGX_MAX_CONF_ERRSTR;
    rc.err.data = errstr;

    /* TODO: NGX_REGEX_CASELESS */

    regex->regex = ngx_http_regex_compile(cf, &rc);
    if (regex->regex == NULL) {
        return NGX_CONF_ERROR;
    }

    regex->code = ngx_http_script_regex_start_code;
    regex->uri = 1;
    regex->name = value[1];

    if (value[2].data[value[2].len - 1] == '?') {

        /* the last "?" drops the original arguments */
        value[2].len--;

    } else {
        regex->add_args = 1;
    }

    last = 0;

    if (ngx_strncmp(value[2].data, "http://", sizeof("http://") - 1) == 0
        || ngx_strncmp(value[2].data, "https://", sizeof("https://") - 1) == 0
        || ngx_strncmp(value[2].data, "$scheme", sizeof("$scheme") - 1) == 0)
    {
        regex->status = NGX_HTTP_MOVED_TEMPORARILY;
        regex->redirect = 1;
        last = 1;
    }

    if (cf->args->nelts == 4) {
        if (ngx_strcmp(value[3].data, "last") == 0) {
            last = 1;

        } else if (ngx_strcmp(value[3].data, "break") == 0) {
            regex->break_cycle = 1;
            last = 1;

        } else if (ngx_strcmp(value[3].data, "redirect") == 0) {
            regex->status = NGX_HTTP_MOVED_TEMPORARILY;
            regex->redirect = 1;
            last = 1;

        } else if (ngx_strcmp(value[3].data, "permanent") == 0) {
            regex->status = NGX_HTTP_MOVED_PERMANENTLY;
            regex->redirect = 1;
            last = 1;

        } else {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "invalid parameter \"%V\"", &value[3]);
            return NGX_CONF_ERROR;
        }
    }

    ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

    sc.cf = cf;
    sc.source = &value[2];
    sc.lengths = &regex->lengths;
    sc.values = &lcf->codes;
    sc.variables = ngx_http_script_variables_count(&value[2]);
    sc.main = regex;
    sc.complete_lengths = 1;
    sc.compile_args = !regex->redirect;

    if (ngx_http_script_compile(&sc) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    regex = sc.main;

    regex->size = sc.size;
    regex->args = sc.args;

    if (sc.variables == 0 && !sc.dup_capture) {
        regex->lengths = NULL;
    }

    regex_end = ngx_http_script_add_code(lcf->codes,
                                      sizeof(ngx_http_script_regex_end_code_t),
                                      &regex);
    if (regex_end == NULL) {
        return NGX_CONF_ERROR;
    }

    regex_end->code = ngx_http_script_regex_end_code;
    regex_end->uri = regex->uri;
    regex_end->args = regex->args;
    regex_end->add_args = regex->add_args;
    regex_end->redirect = regex->redirect;

    if (last) {
        code = ngx_http_script_add_code(lcf->codes, sizeof(uintptr_t), &regex);
        if (code == NULL) {
            return NGX_CONF_ERROR;
        }

        *code = NULL;
    }

    regex->next = (u_char *) lcf->codes->elts + lcf->codes->nelts
                                              - (u_char *) regex;

    return NGX_CONF_OK;
}


static char *
ngx_http_rewrite_return(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_rewrite_loc_conf_t  *lcf = conf;

    u_char                            *p;
    ngx_str_t                         *value, *v;
    ngx_http_script_return_code_t     *ret;
    ngx_http_compile_complex_value_t   ccv;

    ret = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                     sizeof(ngx_http_script_return_code_t));
    if (ret == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    ngx_memzero(ret, sizeof(ngx_http_script_return_code_t));

    ret->code = ngx_http_script_return_code;

    p = value[1].data;

    ret->status = ngx_atoi(p, value[1].len);

    if (ret->status == (uintptr_t) NGX_ERROR) {

        if (cf->args->nelts == 2
            && (ngx_strncmp(p, "http://", sizeof("http://") - 1) == 0
                || ngx_strncmp(p, "https://", sizeof("https://") - 1) == 0
                || ngx_strncmp(p, "$scheme", sizeof("$scheme") - 1) == 0))
        {
            ret->status = NGX_HTTP_MOVED_TEMPORARILY;
            v = &value[1];

        } else {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "invalid return code \"%V\"", &value[1]);
            return NGX_CONF_ERROR;
        }

    } else {

        if (cf->args->nelts == 2) {
            return NGX_CONF_OK;
        }

        v = &value[2];
    }

    ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));

    ccv.cf = cf;
    ccv.value = v;
    ccv.complex_value = &ret->text;

    if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_rewrite_break(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_rewrite_loc_conf_t *lcf = conf;

    ngx_http_script_code_pt  *code;

    code = ngx_http_script_start_code(cf->pool, &lcf->codes, sizeof(uintptr_t));
    if (code == NULL) {
        return NGX_CONF_ERROR;
    }

    *code = ngx_http_script_break_code;

    return NGX_CONF_OK;
}


static char *
ngx_http_rewrite_if(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_rewrite_loc_conf_t  *lcf = conf;

    void                         *mconf;
    char                         *rv;
    u_char                       *elts;
    ngx_uint_t                    i;
    ngx_conf_t                    save;
    ngx_http_module_t            *module;
    ngx_http_conf_ctx_t          *ctx, *pctx;
    ngx_http_core_loc_conf_t     *clcf, *pclcf;
    ngx_http_script_if_code_t    *if_code;
    ngx_http_rewrite_loc_conf_t  *nlcf;

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

    pctx = cf->ctx;
    ctx->main_conf = pctx->main_conf;
    ctx->srv_conf = pctx->srv_conf;

    ctx->loc_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);
    if (ctx->loc_conf == NULL) {
        return NGX_CONF_ERROR;
    }

    for (i = 0; ngx_modules[i]; i++) {
        if (ngx_modules[i]->type != NGX_HTTP_MODULE) {
            continue;
        }

        module = ngx_modules[i]->ctx;

        if (module->create_loc_conf) {

            mconf = module->create_loc_conf(cf);
            if (mconf == NULL) {
                 return NGX_CONF_ERROR;
            }

            ctx->loc_conf[ngx_modules[i]->ctx_index] = mconf;
        }
    }

    pclcf = pctx->loc_conf[ngx_http_core_module.ctx_index];

    clcf = ctx->loc_conf[ngx_http_core_module.ctx_index];
    clcf->loc_conf = ctx->loc_conf;
    clcf->name = pclcf->name;
    clcf->noname = 1;

    if (ngx_http_add_location(cf, &pclcf->locations, clcf) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    if (ngx_http_rewrite_if_condition(cf, lcf) != NGX_CONF_OK) {
        return NGX_CONF_ERROR;
    }

    if_code = ngx_array_push_n(lcf->codes, sizeof(ngx_http_script_if_code_t));
    if (if_code == NULL) {
        return NGX_CONF_ERROR;
    }

    if_code->code = ngx_http_script_if_code;

    elts = lcf->codes->elts;


    /* the inner directives must be compiled to the same code array */

    nlcf = ctx->loc_conf[ngx_http_rewrite_module.ctx_index];
    nlcf->codes = lcf->codes;


    save = *cf;
    cf->ctx = ctx;

    if (pclcf->name.len == 0) {
        if_code->loc_conf = NULL;
        cf->cmd_type = NGX_HTTP_SIF_CONF;

    } else {
        if_code->loc_conf = ctx->loc_conf;
        cf->cmd_type = NGX_HTTP_LIF_CONF;
    }

    rv = ngx_conf_parse(cf, NULL);

    *cf = save;

    if (rv != NGX_CONF_OK) {
        return rv;
    }


    if (elts != lcf->codes->elts) {
        if_code = (ngx_http_script_if_code_t *)
                   ((u_char *) if_code + ((u_char *) lcf->codes->elts - elts));
    }

    if_code->next = (u_char *) lcf->codes->elts + lcf->codes->nelts
                                                - (u_char *) if_code;

    /* the code array belong to parent block */

    nlcf->codes = NULL;

    return NGX_CONF_OK;
}


static char *
ngx_http_rewrite_if_condition(ngx_conf_t *cf, ngx_http_rewrite_loc_conf_t *lcf)
{
    u_char                        *p;
    size_t                         len;
    ngx_str_t                     *value;
    ngx_uint_t                     cur, last;
    ngx_regex_compile_t            rc;
    ngx_http_script_code_pt       *code;
    ngx_http_script_file_code_t   *fop;
    ngx_http_script_regex_code_t  *regex;
    u_char                         errstr[NGX_MAX_CONF_ERRSTR];

    value = cf->args->elts;
    last = cf->args->nelts - 1;

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

    if (value[1].len == 1) {
        cur = 2;

    } else {
        cur = 1;
        value[1].len--;
        value[1].data++;
    }

    if (value[last].len < 1 || value[last].data[value[last].len - 1] != ')') {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid condition \"%V\"", &value[last]);
        return NGX_CONF_ERROR;
    }

    if (value[last].len == 1) {
        last--;

    } else {
        value[last].len--;
        value[last].data[value[last].len] = '\0';
    }

    len = value[cur].len;
    p = value[cur].data;

    if (len > 1 && p[0] == '$') {

        if (cur != last && cur + 2 != last) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "invalid condition \"%V\"", &value[cur]);
            return NGX_CONF_ERROR;
        }

        if (ngx_http_rewrite_variable(cf, lcf, &value[cur]) != NGX_CONF_OK) {
            return NGX_CONF_ERROR;
        }

        if (cur == last) {
            return NGX_CONF_OK;
        }

        cur++;

        len = value[cur].len;
        p = value[cur].data;

        if (len == 1 && p[0] == '=') {

            if (ngx_http_rewrite_value(cf, lcf, &value[last]) != NGX_CONF_OK) {
                return NGX_CONF_ERROR;
            }

            code = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                              sizeof(uintptr_t));
            if (code == NULL) {
                return NGX_CONF_ERROR;
            }

            *code = ngx_http_script_equal_code;

            return NGX_CONF_OK;
        }

        if (len == 2 && p[0] == '!' && p[1] == '=') {

            if (ngx_http_rewrite_value(cf, lcf, &value[last]) != NGX_CONF_OK) {
                return NGX_CONF_ERROR;
            }

            code = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                              sizeof(uintptr_t));
            if (code == NULL) {
                return NGX_CONF_ERROR;
            }

            *code = ngx_http_script_not_equal_code;
            return NGX_CONF_OK;
        }

        if ((len == 1 && p[0] == '~')
            || (len == 2 && p[0] == '~' && p[1] == '*')
            || (len == 2 && p[0] == '!' && p[1] == '~')
            || (len == 3 && p[0] == '!' && p[1] == '~' && p[2] == '*'))
        {
            regex = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                         sizeof(ngx_http_script_regex_code_t));
            if (regex == NULL) {
                return NGX_CONF_ERROR;
            }

            ngx_memzero(regex, sizeof(ngx_http_script_regex_code_t));

            ngx_memzero(&rc, sizeof(ngx_regex_compile_t));

            rc.pattern = value[last];
            rc.options = (p[len - 1] == '*') ? NGX_REGEX_CASELESS : 0;
            rc.err.len = NGX_MAX_CONF_ERRSTR;
            rc.err.data = errstr;

            regex->regex = ngx_http_regex_compile(cf, &rc);
            if (regex->regex == NULL) {
                return NGX_CONF_ERROR;
            }

            regex->code = ngx_http_script_regex_start_code;
            regex->next = sizeof(ngx_http_script_regex_code_t);
            regex->test = 1;
            if (p[0] == '!') {
                regex->negative_test = 1;
            }
            regex->name = value[last];

            return NGX_CONF_OK;
        }

        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "unexpected \"%V\" in condition", &value[cur]);
        return NGX_CONF_ERROR;

    } else if ((len == 2 && p[0] == '-')
               || (len == 3 && p[0] == '!' && p[1] == '-'))
    {
        if (cur + 1 != last) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "invalid condition \"%V\"", &value[cur]);
            return NGX_CONF_ERROR;
        }

        value[last].data[value[last].len] = '\0';
        value[last].len++;

        if (ngx_http_rewrite_value(cf, lcf, &value[last]) != NGX_CONF_OK) {
            return NGX_CONF_ERROR;
        }

        fop = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                          sizeof(ngx_http_script_file_code_t));
        if (fop == NULL) {
            return NGX_CONF_ERROR;
        }

        fop->code = ngx_http_script_file_code;

        if (p[1] == 'f') {
            fop->op = ngx_http_script_file_plain;
            return NGX_CONF_OK;
        }

        if (p[1] == 'd') {
            fop->op = ngx_http_script_file_dir;
            return NGX_CONF_OK;
        }

        if (p[1] == 'e') {
            fop->op = ngx_http_script_file_exists;
            return NGX_CONF_OK;
        }

        if (p[1] == 'x') {
            fop->op = ngx_http_script_file_exec;
            return NGX_CONF_OK;
        }

        if (p[0] == '!') {
            if (p[2] == 'f') {
                fop->op = ngx_http_script_file_not_plain;
                return NGX_CONF_OK;
            }

            if (p[2] == 'd') {
                fop->op = ngx_http_script_file_not_dir;
                return NGX_CONF_OK;
            }

            if (p[2] == 'e') {
                fop->op = ngx_http_script_file_not_exists;
                return NGX_CONF_OK;
            }

            if (p[2] == 'x') {
                fop->op = ngx_http_script_file_not_exec;
                return NGX_CONF_OK;
            }
        }

        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid condition \"%V\"", &value[cur]);
        return NGX_CONF_ERROR;
    }

    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                       "invalid condition \"%V\"", &value[cur]);

    return NGX_CONF_ERROR;
}


static char *
ngx_http_rewrite_variable(ngx_conf_t *cf, ngx_http_rewrite_loc_conf_t *lcf,
    ngx_str_t *value)
{
    ngx_int_t                    index;
    ngx_http_script_var_code_t  *var_code;

    value->len--;
    value->data++;

    index = ngx_http_get_variable_index(cf, value);

    if (index == NGX_ERROR) {
        return NGX_CONF_ERROR;
    }

    var_code = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                          sizeof(ngx_http_script_var_code_t));
    if (var_code == NULL) {
        return NGX_CONF_ERROR;
    }

    var_code->code = ngx_http_script_var_code;
    var_code->index = index;

    return NGX_CONF_OK;
}


static char *
ngx_http_rewrite_set(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_rewrite_loc_conf_t  *lcf = conf;

    ngx_int_t                            index;
    ngx_str_t                           *value;
    ngx_http_variable_t                 *v;
    ngx_http_script_var_code_t          *vcode;
    ngx_http_script_var_handler_code_t  *vhcode;

    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_CHANGEABLE);
    if (v == NULL) {
        return NGX_CONF_ERROR;
    }

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

    if (v->get_handler == NULL
        && ngx_strncasecmp(value[1].data, (u_char *) "http_", 5) != 0
        && ngx_strncasecmp(value[1].data, (u_char *) "sent_http_", 10) != 0
        && ngx_strncasecmp(value[1].data, (u_char *) "upstream_http_", 14) != 0)
    {
        v->get_handler = ngx_http_rewrite_var;
        v->data = index;
    }

    if (ngx_http_rewrite_value(cf, lcf, &value[2]) != NGX_CONF_OK) {
        return NGX_CONF_ERROR;
    }

    if (v->set_handler) {
        vhcode = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                   sizeof(ngx_http_script_var_handler_code_t));
        if (vhcode == NULL) {
            return NGX_CONF_ERROR;
        }

        vhcode->code = ngx_http_script_var_set_handler_code;
        vhcode->handler = v->set_handler;
        vhcode->data = v->data;

        return NGX_CONF_OK;
    }

    vcode = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                       sizeof(ngx_http_script_var_code_t));
    if (vcode == NULL) {
        return NGX_CONF_ERROR;
    }

    vcode->code = ngx_http_script_set_var_code;
    vcode->index = (uintptr_t) index;

    return NGX_CONF_OK;
}


static char *
ngx_http_rewrite_value(ngx_conf_t *cf, ngx_http_rewrite_loc_conf_t *lcf,
    ngx_str_t *value)
{
    ngx_int_t                              n;
    ngx_http_script_compile_t              sc;
    ngx_http_script_value_code_t          *val;
    ngx_http_script_complex_value_code_t  *complex;

    n = ngx_http_script_variables_count(value);

    if (n == 0) {
        val = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                         sizeof(ngx_http_script_value_code_t));
        if (val == NULL) {
            return NGX_CONF_ERROR;
        }

        n = ngx_atoi(value->data, value->len);

        if (n == NGX_ERROR) {
            n = 0;
        }

        val->code = ngx_http_script_value_code;
        val->value = (uintptr_t) n;
        val->text_len = (uintptr_t) value->len;
        val->text_data = (uintptr_t) value->data;

        return NGX_CONF_OK;
    }

    complex = ngx_http_script_start_code(cf->pool, &lcf->codes,
                                 sizeof(ngx_http_script_complex_value_code_t));
    if (complex == NULL) {
        return NGX_CONF_ERROR;
    }

    complex->code = ngx_http_script_complex_value_code;
    complex->lengths = NULL;

    ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

    sc.cf = cf;
    sc.source = value;
    sc.lengths = &complex->lengths;
    sc.values = &lcf->codes;
    sc.variables = n;
    sc.complete_lengths = 1;

    if (ngx_http_script_compile(&sc) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}