mod_cgi.c

linux网络服务器工具

        for (bucket = APR_BRIGADE_FIRST(bb);
             bucket != APR_BRIGADE_SENTINEL(bb);
             bucket = APR_BUCKET_NEXT(bucket))
        {
            const char *data;
            apr_size_t len;

            if (APR_BUCKET_IS_EOS(bucket)) {
                seen_eos = 1;
                break;
            }

            /* We can't do much with this. */
            if (APR_BUCKET_IS_FLUSH(bucket)) {
                continue;
            }

            /* If the child stopped, we still must read to EOS. */
            if (child_stopped_reading) {
                continue;
            }

            /* read */
            apr_bucket_read(bucket, &data, &len, APR_BLOCK_READ);

            if (conf->logname && dbpos < conf->bufbytes) {
                int cursize;

                if ((dbpos + len) > conf->bufbytes) {
                    cursize = conf->bufbytes - dbpos;
                }
                else {
                    cursize = len;
                }
                memcpy(dbuf + dbpos, data, cursize);
                dbpos += cursize;
            }

            /* Keep writing data to the child until done or too much time
             * elapses with no progress or an error occurs.
             */
            rv = apr_file_write_full(script_out, data, len, NULL);

            if (rv != APR_SUCCESS) {
                /* silly script stopped reading, soak up remaining message */
                child_stopped_reading = 1;
            }
        }
        apr_brigade_cleanup(bb);
    }
    while (!seen_eos);

    if (conf->logname) {
        dbuf[dbpos] = '\0';
    }
    /* Is this flush really needed? */
    apr_file_flush(script_out);
    apr_file_close(script_out);

    AP_DEBUG_ASSERT(script_in != NULL);

    apr_brigade_cleanup(bb);

#if APR_FILES_AS_SOCKETS
    apr_file_pipe_timeout_set(script_in, 0);
    apr_file_pipe_timeout_set(script_err, 0);

    b = cgi_bucket_create(r, script_in, script_err, c->bucket_alloc);
#else
    b = apr_bucket_pipe_create(script_in, c->bucket_alloc);
#endif
    APR_BRIGADE_INSERT_TAIL(bb, b);
    b = apr_bucket_eos_create(c->bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(bb, b);

    /* Handle script return... */
    if (!nph) {
        const char *location;
        char sbuf[MAX_STRING_LEN];
        int ret;

        if ((ret = ap_scan_script_header_err_brigade(r, bb, sbuf))) {
            ret = log_script(r, conf, ret, dbuf, sbuf, bb, script_err);

            /*
             * ret could be HTTP_NOT_MODIFIED in the case that the CGI script
             * does not set an explicit status and ap_meets_conditions, which
             * is called by ap_scan_script_header_err_brigade, detects that
             * the conditions of the requests are met and the response is
             * not modified.
             * In this case set r->status and return OK in order to prevent
             * running through the error processing stack as this would
             * break with mod_cache, if the conditions had been set by
             * mod_cache itself to validate a stale entity.
             * BTW: We circumvent the error processing stack anyway if the
             * CGI script set an explicit status code (whatever it is) and
             * the only possible values for ret here are:
             *
             * HTTP_NOT_MODIFIED          (set by ap_meets_conditions)
             * HTTP_PRECONDITION_FAILED   (set by ap_meets_conditions)
             * HTTP_INTERNAL_SERVER_ERROR (if something went wrong during the
             * processing of the response of the CGI script, e.g broken headers
             * or a crashed CGI process).
             */
            if (ret == HTTP_NOT_MODIFIED) {
                r->status = ret;
                return OK;
            }

            return ret;
        }

        location = apr_table_get(r->headers_out, "Location");

        if (location && r->status == 200) {
            /* For a redirect whether internal or not, discard any
             * remaining stdout from the script, and log any remaining
             * stderr output, as normal. */
            discard_script_output(bb);
            apr_brigade_destroy(bb);
            apr_file_pipe_timeout_set(script_err, r->server->timeout);
            log_script_err(r, script_err);
        }

        if (location && location[0] == '/' && r->status == 200) {
            /* This redirect needs to be a GET no matter what the original
             * method was.
             */
            r->method = apr_pstrdup(r->pool, "GET");
            r->method_number = M_GET;

            /* We already read the message body (if any), so don't allow
             * the redirected request to think it has one.  We can ignore
             * Transfer-Encoding, since we used REQUEST_CHUNKED_ERROR.
             */
            apr_table_unset(r->headers_in, "Content-Length");

            ap_internal_redirect_handler(location, r);
            return OK;
        }
        else if (location && r->status == 200) {
            /* XX Note that if a script wants to produce its own Redirect
             * body, it now has to explicitly *say* "Status: 302"
             */
            return HTTP_MOVED_TEMPORARILY;
        }

        rv = ap_pass_brigade(r->output_filters, bb);
    }
    else /* nph */ {
        struct ap_filter_t *cur;

        /* get rid of all filters up through protocol...  since we
         * haven't parsed off the headers, there is no way they can
         * work
         */

        cur = r->proto_output_filters;
        while (cur && cur->frec->ftype < AP_FTYPE_CONNECTION) {
            cur = cur->next;
        }
        r->output_filters = r->proto_output_filters = cur;

        rv = ap_pass_brigade(r->output_filters, bb);
    }

    /* don't soak up script output if errors occurred writing it
     * out...  otherwise, we prolong the life of the script when the
     * connection drops or we stopped sending output for some other
     * reason */
    if (rv == APR_SUCCESS && !r->connection->aborted) {
        apr_file_pipe_timeout_set(script_err, r->server->timeout);
        log_script_err(r, script_err);
    }

    apr_file_close(script_err);

    return OK;                      /* NOT r->status, even if it has changed. */
}

/*============================================================================
 *============================================================================
 * This is the beginning of the cgi filter code moved from mod_include. This
 *   is the code required to handle the "exec" SSI directive.
 *============================================================================
 *============================================================================*/
static apr_status_t include_cgi(include_ctx_t *ctx, ap_filter_t *f,
                                apr_bucket_brigade *bb, char *s)
{
    request_rec *r = f->r;
    request_rec *rr = ap_sub_req_lookup_uri(s, r, f->next);
    int rr_status;

    if (rr->status != HTTP_OK) {
        ap_destroy_sub_req(rr);
        return APR_EGENERAL;
    }

    /* No hardwired path info or query allowed */
    if ((rr->path_info && rr->path_info[0]) || rr->args) {
        ap_destroy_sub_req(rr);
        return APR_EGENERAL;
    }
    if (rr->finfo.filetype != APR_REG) {
        ap_destroy_sub_req(rr);
        return APR_EGENERAL;
    }

    /* Script gets parameters of the *document*, for back compatibility */
    rr->path_info = r->path_info;       /* hard to get right; see mod_cgi.c */
    rr->args = r->args;

    /* Force sub_req to be treated as a CGI request, even if ordinary
     * typing rules would have called it something else.
     */
    ap_set_content_type(rr, CGI_MAGIC_TYPE);

    /* Run it. */
    rr_status = ap_run_sub_req(rr);
    if (ap_is_HTTP_REDIRECT(rr_status)) {
        const char *location = apr_table_get(rr->headers_out, "Location");

        if (location) {
            char *buffer;

            location = ap_escape_html(rr->pool, location);
            buffer = apr_pstrcat(ctx->pool, "<a href=\"", location, "\">",
                                 location, "</a>", NULL);

            APR_BRIGADE_INSERT_TAIL(bb, apr_bucket_pool_create(buffer,
                                    strlen(buffer), ctx->pool,
                                    f->c->bucket_alloc));
        }
    }

    ap_destroy_sub_req(rr);

    return APR_SUCCESS;
}

static apr_status_t include_cmd(include_ctx_t *ctx, ap_filter_t *f,
                                apr_bucket_brigade *bb, const char *command)
{
    cgi_exec_info_t  e_info;
    const char **argv;
    apr_file_t *script_out = NULL, *script_in = NULL, *script_err = NULL;
    apr_status_t rv;
    request_rec *r = f->r;

    add_ssi_vars(r);

    e_info.process_cgi = 0;
    e_info.cmd_type    = APR_SHELLCMD;
    e_info.detached    = 0;
    e_info.in_pipe     = APR_NO_PIPE;
    e_info.out_pipe    = APR_FULL_BLOCK;
    e_info.err_pipe    = APR_NO_PIPE;
    e_info.prog_type   = RUN_AS_SSI;
    e_info.bb          = &bb;
    e_info.ctx         = ctx;
    e_info.next        = f->next;
    e_info.addrspace   = 0;

    if ((rv = cgi_build_command(&command, &argv, r, r->pool,
                                &e_info)) != APR_SUCCESS) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
                      "don't know how to spawn cmd child process: %s",
                      r->filename);
        return rv;
    }

    /* run the script in its own process */
    if ((rv = run_cgi_child(&script_out, &script_in, &script_err,
                            command, argv, r, r->pool,
                            &e_info)) != APR_SUCCESS) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
                      "couldn't spawn child process: %s", r->filename);
        return rv;
    }

    APR_BRIGADE_INSERT_TAIL(bb, apr_bucket_pipe_create(script_in,
                            f->c->bucket_alloc));
    ctx->flush_now = 1;

    /* We can't close the pipe here, because we may return before the
     * full CGI has been sent to the network.  That's okay though,
     * because we can rely on the pool to close the pipe for us.
     */
    return APR_SUCCESS;
}

static apr_status_t handle_exec(include_ctx_t *ctx, ap_filter_t *f,
                                apr_bucket_brigade *bb)
{
    char *tag = NULL;
    char *tag_val = NULL;
    request_rec *r = f->r;
    char *file = r->filename;
    char parsed_string[MAX_STRING_LEN];

    if (!ctx->argc) {
        ap_log_rerror(APLOG_MARK,
                      (ctx->flags & SSI_FLAG_PRINTING)
                          ? APLOG_ERR : APLOG_WARNING,
                      0, r, "missing argument for exec element in %s",
                      r->filename);
    }

    if (!(ctx->flags & SSI_FLAG_PRINTING)) {
        return APR_SUCCESS;
    }

    if (!ctx->argc) {
        SSI_CREATE_ERROR_BUCKET(ctx, f, bb);
        return APR_SUCCESS;
    }

    if (ctx->flags & SSI_FLAG_NO_EXEC) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "exec used but not allowed "
                      "in %s", r->filename);
        SSI_CREATE_ERROR_BUCKET(ctx, f, bb);
        return APR_SUCCESS;
    }

    while (1) {
        cgi_pfn_gtv(ctx, &tag, &tag_val, SSI_VALUE_DECODED);
        if (!tag || !tag_val) {
            break;
        }

        if (!strcmp(tag, "cmd")) {
            apr_status_t rv;

            cgi_pfn_ps(ctx, tag_val, parsed_string, sizeof(parsed_string),
                       SSI_EXPAND_LEAVE_NAME);

            rv = include_cmd(ctx, f, bb, parsed_string);
            if (rv != APR_SUCCESS) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "execution failure "
                              "for parameter \"%s\" to tag exec in file %s",
                              tag, r->filename);
                SSI_CREATE_ERROR_BUCKET(ctx, f, bb);
                break;
            }
        }
        else if (!strcmp(tag, "cgi")) {
            apr_status_t rv;

            cgi_pfn_ps(ctx, tag_val, parsed_string, sizeof(parsed_string),
                       SSI_EXPAND_DROP_NAME);

            rv = include_cgi(ctx, f, bb, parsed_string);
            if (rv != APR_SUCCESS) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "invalid CGI ref "
                              "\"%s\" in %s", tag_val, file);
                SSI_CREATE_ERROR_BUCKET(ctx, f, bb);
                break;
            }
        }
        else {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "unknown parameter "
                          "\"%s\" to tag exec in %s", tag, file);
            SSI_CREATE_ERROR_BUCKET(ctx, f, bb);
            break;
        }
    }

    return APR_SUCCESS;
}


/*============================================================================
 *============================================================================
 * This is the end of the cgi filter code moved from mod_include.
 *============================================================================
 *============================================================================*/


static int cgi_post_config(apr_pool_t *p, apr_pool_t *plog,
                                apr_pool_t *ptemp, server_rec *s)
{
    cgi_pfn_reg_with_ssi = APR_RETRIEVE_OPTIONAL_FN(ap_register_include_handler);
    cgi_pfn_gtv          = APR_RETRIEVE_OPTIONAL_FN(ap_ssi_get_tag_and_value);
    cgi_pfn_ps           = APR_RETRIEVE_OPTIONAL_FN(ap_ssi_parse_string);

    if ((cgi_pfn_reg_with_ssi) && (cgi_pfn_gtv) && (cgi_pfn_ps)) {
        /* Required by mod_include filter. This is how mod_cgi registers
         *   with mod_include to provide processing of the exec directive.
         */
        cgi_pfn_reg_with_ssi("exec", handle_exec);
    }

    /* This is the means by which unusual (non-unix) os's may find alternate
     * means to run a given command (e.g. shebang/registry parsing on Win32)
     */
    cgi_build_command    = APR_RETRIEVE_OPTIONAL_FN(ap_cgi_build_command);
    if (!cgi_build_command) {
        cgi_build_command = default_build_command;
    }
    return OK;
}

static void register_hooks(apr_pool_t *p)
{
    static const char * const aszPre[] = { "mod_include.c", NULL };
    ap_hook_handler(cgi_handler, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_post_config(cgi_post_config, aszPre, NULL, APR_HOOK_REALLY_FIRST);
}

module AP_MODULE_DECLARE_DATA cgi_module =
{
    STANDARD20_MODULE_STUFF,
    NULL,                        /* dir config creater */
    NULL,                        /* dir merger --- default is to override */
    create_cgi_config,           /* server config */
    merge_cgi_config,            /* merge server config */
    cgi_cmds,                    /* command apr_table_t */
    register_hooks               /* register hooks */
};