mod_proxy_scgi.c revision 36ef8f77bffe75d1aa327882be1b5bdbe2ff567a
/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* mod_proxy_scgi.c
* Proxy backend module for the SCGI protocol
* (http://python.ca/scgi/protocol.txt)
*
* Andr� Malo (nd/perlig.de), August 2007
*/
#define APR_WANT_MEMFUNC
#define APR_WANT_STRFUNC
#include "apr_strings.h"
#include "apr_hooks.h"
#include "apr_optional_hooks.h"
#include "apr_buckets.h"
#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "http_protocol.h"
#include "http_request.h"
#include "util_script.h"
#include "mod_proxy.h"
#define SCHEME "scgi"
#define PROXY_FUNCTION "SCGI"
#define SCGI_MAGIC "SCGI"
#define SCGI_PROTOCOL_VERSION "1"
#define SCGI_DEFAULT_PORT (4000)
/* just protect from typos */
#define CONTENT_LENGTH "CONTENT_LENGTH"
#define GATEWAY_INTERFACE "GATEWAY_INTERFACE"
module AP_MODULE_DECLARE_DATA proxy_scgi_module;
typedef enum {
scgi_internal_redirect,
scgi_sendfile
} scgi_request_type;
typedef struct {
const char *location; /* target URL */
scgi_request_type type; /* type of request */
} scgi_request_config;
const char *scgi_sendfile_off = "off";
const char *scgi_sendfile_on = "X-Sendfile";
typedef struct {
const char *sendfile;
int internal_redirect;
} scgi_config;
/*
* We create our own bucket type, which is actually derived (c&p) from the
* socket bucket.
* Maybe some time this should be made more abstract (like passing an
* interception function to read or something) and go into the ap_ or
* even apr_ namespace.
*/
typedef struct {
apr_socket_t *sock;
apr_off_t *counter;
} socket_ex_data;
static apr_bucket *bucket_socket_ex_create(socket_ex_data *data,
apr_bucket_alloc_t *list);
static apr_status_t bucket_socket_ex_read(apr_bucket *a, const char **str,
apr_size_t *len,
apr_read_type_e block)
{
socket_ex_data *data = a->data;
apr_socket_t *p = data->sock;
char *buf;
apr_status_t rv;
apr_interval_time_t timeout;
if (block == APR_NONBLOCK_READ) {
apr_socket_timeout_get(p, &timeout);
apr_socket_timeout_set(p, 0);
}
*str = NULL;
*len = APR_BUCKET_BUFF_SIZE;
buf = apr_bucket_alloc(*len, a->list);
rv = apr_socket_recv(p, buf, len);
if (block == APR_NONBLOCK_READ) {
apr_socket_timeout_set(p, timeout);
}
if (rv != APR_SUCCESS && rv != APR_EOF) {
apr_bucket_free(buf);
return rv;
}
if (*len > 0) {
apr_bucket_heap *h;
/* count for stats */
*data->counter += *len;
/* Change the current bucket to refer to what we read */
a = apr_bucket_heap_make(a, buf, *len, apr_bucket_free);
h = a->data;
h->alloc_len = APR_BUCKET_BUFF_SIZE; /* note the real buffer size */
*str = buf;
APR_BUCKET_INSERT_AFTER(a, bucket_socket_ex_create(data, a->list));
}
else {
apr_bucket_free(buf);
a = apr_bucket_immortal_make(a, "", 0);
*str = a->data;
}
return APR_SUCCESS;
}
static const apr_bucket_type_t bucket_type_socket_ex = {
"SOCKET_EX", 5, APR_BUCKET_DATA,
apr_bucket_destroy_noop,
bucket_socket_ex_read,
apr_bucket_setaside_notimpl,
apr_bucket_split_notimpl,
apr_bucket_copy_notimpl
};
static apr_bucket *bucket_socket_ex_make(apr_bucket *b, socket_ex_data *data)
{
b->type = &bucket_type_socket_ex;
b->length = (apr_size_t)(-1);
b->start = -1;
b->data = data;
return b;
}
static apr_bucket *bucket_socket_ex_create(socket_ex_data *data,
apr_bucket_alloc_t *list)
{
apr_bucket *b = apr_bucket_alloc(sizeof(*b), list);
APR_BUCKET_INIT(b);
b->free = apr_bucket_free;
b->list = list;
return bucket_socket_ex_make(b, data);
}
/*
* Canonicalize scgi-like URLs.
*/
static int scgi_canon(request_rec *r, char *url)
{
char *host, sport[sizeof(":65535")];
const char *err, *path;
apr_port_t port = SCGI_DEFAULT_PORT;
if (strncasecmp(url, SCHEME "://", sizeof(SCHEME) + 2)) {
return DECLINED;
}
url += sizeof(SCHEME); /* Keep slashes */
err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
if (err) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
"error parsing URL %s: %s", url, err);
return HTTP_BAD_REQUEST;
}
apr_snprintf(sport, sizeof(sport), ":%u", port);
if (ap_strchr(host, ':')) { /* if literal IPv6 address */
host = apr_pstrcat(r->pool, "[", host, "]", NULL);
}
path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0,
r->proxyreq);
if (!path) {
return HTTP_BAD_REQUEST;
}
r->filename = apr_pstrcat(r->pool, "proxy:" SCHEME "://", host, sport, "/",
path, NULL);
r->path_info = apr_pstrcat(r->pool, "/", path, NULL);
return OK;
}
/*
* Send a block of data, ensure, everything is sent
*/
static int sendall(proxy_conn_rec *conn, const char *buf, apr_size_t length,
request_rec *r)
{
apr_status_t rv;
apr_size_t written;
while (length > 0) {
written = length;
if ((rv = apr_socket_send(conn->sock, buf, &written)) != APR_SUCCESS) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r,
"proxy: " PROXY_FUNCTION ": sending data to "
"%s:%u failed", conn->hostname, conn->port);
return HTTP_SERVICE_UNAVAILABLE;
}
/* count for stats */
conn->worker->s->transferred += written;
buf += written;
length -= written;
}
return OK;
}
/*
* Send SCGI header block
*/
static int send_headers(request_rec *r, proxy_conn_rec *conn)
{
char *buf, *cp, *bodylen;
const char *ns_len;
const apr_array_header_t *env_table;
const apr_table_entry_t *env;
int j;
apr_size_t len, bodylen_size;
apr_size_t headerlen = sizeof(CONTENT_LENGTH)
+ sizeof(SCGI_MAGIC)
+ sizeof(SCGI_PROTOCOL_VERSION);
ap_add_common_vars(r);
ap_add_cgi_vars(r);
/*
* The header blob basically takes the environment and concatenates
* keys and values using 0 bytes. There are special treatments here:
* - GATEWAY_INTERFACE and SCGI_MAGIC are dropped
* - CONTENT_LENGTH is always set and must be sent as the very first
* variable
*
* Additionally it's wrapped into a so-called netstring (see SCGI spec)
*/
env_table = apr_table_elts(r->subprocess_env);
env = (apr_table_entry_t *)env_table->elts;
for (j = 0; j < env_table->nelts; ++j) {
if ( (!strcmp(env[j].key, GATEWAY_INTERFACE))
|| (!strcmp(env[j].key, CONTENT_LENGTH))
|| (!strcmp(env[j].key, SCGI_MAGIC))) {
continue;
}
headerlen += strlen(env[j].key) + strlen(env[j].val) + 2;
}
bodylen = apr_psprintf(r->pool, "%" APR_OFF_T_FMT, r->remaining);
bodylen_size = strlen(bodylen) + 1;
headerlen += bodylen_size;
ns_len = apr_psprintf(r->pool, "%" APR_SIZE_T_FMT ":", headerlen);
len = strlen(ns_len);
headerlen += len + 1; /* 1 == , */
cp = buf = apr_palloc(r->pool, headerlen);
memcpy(cp, ns_len, len);
cp += len;
memcpy(cp, CONTENT_LENGTH, sizeof(CONTENT_LENGTH));
cp += sizeof(CONTENT_LENGTH);
memcpy(cp, bodylen, bodylen_size);
cp += bodylen_size;
memcpy(cp, SCGI_MAGIC, sizeof(SCGI_MAGIC));
cp += sizeof(SCGI_MAGIC);
memcpy(cp, SCGI_PROTOCOL_VERSION, sizeof(SCGI_PROTOCOL_VERSION));
cp += sizeof(SCGI_PROTOCOL_VERSION);
for (j = 0; j < env_table->nelts; ++j) {
if ( (!strcmp(env[j].key, GATEWAY_INTERFACE))
|| (!strcmp(env[j].key, CONTENT_LENGTH))
|| (!strcmp(env[j].key, SCGI_MAGIC))) {
continue;
}
len = strlen(env[j].key) + 1;
memcpy(cp, env[j].key, len);
cp += len;
len = strlen(env[j].val) + 1;
memcpy(cp, env[j].val, len);
cp += len;
}
*cp++ = ',';
return sendall(conn, buf, headerlen, r);
}
/*
* Send request body (if any)
*/
static int send_request_body(request_rec *r, proxy_conn_rec *conn)
{
if (ap_should_client_block(r)) {
char *buf = apr_palloc(r->pool, AP_IOBUFSIZE);
int status;
apr_size_t readlen;
readlen = ap_get_client_block(r, buf, AP_IOBUFSIZE);
while (readlen > 0) {
status = sendall(conn, buf, readlen, r);
if (status != OK) {
return HTTP_SERVICE_UNAVAILABLE;
}
readlen = ap_get_client_block(r, buf, AP_IOBUFSIZE);
}
if (readlen == -1) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
"proxy: " PROXY_FUNCTION ": receiving request body "
"failed");
return HTTP_INTERNAL_SERVER_ERROR;
}
}
return OK;
}
/*
* Fetch response from backend and pass back to the front
*/
static int pass_response(request_rec *r, proxy_conn_rec *conn)
{
apr_bucket_brigade *bb;
apr_bucket *b;
const char *location;
scgi_config *conf;
socket_ex_data *sock_data;
int status;
sock_data = apr_palloc(r->pool, sizeof(*sock_data));
sock_data->sock = conn->sock;
sock_data->counter = &conn->worker->s->read;
bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
b = bucket_socket_ex_create(sock_data, r->connection->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(bb, b);
b = apr_bucket_eos_create(r->connection->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(bb, b);
status = ap_scan_script_header_err_brigade(r, bb, NULL);
if (status != OK) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
"proxy: " PROXY_FUNCTION ": error reading response "
"headers from %s:%u", conn->hostname, conn->port);
r->status_line = NULL;
apr_brigade_destroy(bb);
return status;
}
conf = ap_get_module_config(r->per_dir_config, &proxy_scgi_module);
if (conf->sendfile && conf->sendfile != scgi_sendfile_off) {
short err = 1;
location = apr_table_get(r->err_headers_out, conf->sendfile);
if (!location) {
err = 0;
location = apr_table_get(r->headers_out, conf->sendfile);
}
if (location) {
scgi_request_config *req_conf = apr_palloc(r->pool,
sizeof(*req_conf));
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
"proxy: " PROXY_FUNCTION ": Found %s: %s - "
"preparing subrequest.",
conf->sendfile, location);
if (err) {
apr_table_unset(r->err_headers_out, conf->sendfile);
}
else {
apr_table_unset(r->headers_out, conf->sendfile);
}
req_conf->location = location;
req_conf->type = scgi_sendfile;
ap_set_module_config(r->request_config, &proxy_scgi_module,
req_conf);
apr_brigade_destroy(bb);
return OK;
}
}
if (conf->internal_redirect && r->status == HTTP_OK) {
location = apr_table_get(r->headers_out, "Location");
if (location && *location == '/') {
scgi_request_config *req_conf = apr_palloc(r->pool,
sizeof(*req_conf));
req_conf->location = location;
req_conf->type = scgi_internal_redirect;
ap_set_module_config(r->request_config, &proxy_scgi_module,
req_conf);
apr_brigade_destroy(bb);
return OK;
}
}
/* XXX: What could we do with that return code? */
(void)ap_pass_brigade(r->output_filters, bb);
return OK;
}
/*
* Internal redirect / subrequest handler, working on request_status hook
*/
static int scgi_request_status(int *status, request_rec *r)
{
scgi_request_config *req_conf;
if ( (*status == OK)
&& (req_conf = ap_get_module_config(r->request_config,
&proxy_scgi_module))) {
switch (req_conf->type) {
case scgi_internal_redirect:
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
"proxy: " PROXY_FUNCTION ": Internal redirect to %s",
req_conf->location);
r->status_line = NULL;
if (r->method_number != M_GET) {
/* keep HEAD, which is passed around as M_GET, too */
r->method = "GET";
r->method_number = M_GET;
}
apr_table_unset(r->headers_in, "Content-Length");
ap_internal_redirect_handler(req_conf->location, r);
return OK;
/* break; */
case scgi_sendfile:
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
"proxy: " PROXY_FUNCTION ": File subrequest to %s",
req_conf->location);
do {
request_rec *rr;
rr = ap_sub_req_lookup_file(req_conf->location, r,
r->output_filters);
if (rr->status == HTTP_OK && rr->finfo.filetype != 0) {
/*
* We don't touch Content-Length here. It might be
* borked (there's plenty of room for a race condition).
* Either the backend sets it or it's gonna be chunked.
*/
ap_run_sub_req(rr);
}
else {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
"Subrequest to file '%s' not possible. "
"(rr->status=%d, rr->finfo.filetype=%d)",
req_conf->location, rr->status,
rr->finfo.filetype);
*status = HTTP_INTERNAL_SERVER_ERROR;
return *status;
}
} while(0);
return OK;
/* break; */
}
}
return DECLINED;
}
/*
* This handles scgi:(dest) URLs
*/
static int scgi_handler(request_rec *r, proxy_worker *worker,
proxy_server_conf *conf, char *url,
const char *proxyname, apr_port_t proxyport)
{
int status;
proxy_conn_rec *backend = NULL;
apr_pool_t *p = r->pool;
apr_uri_t *uri = apr_palloc(r->pool, sizeof(*uri));
char dummy;
if (strncasecmp(url, SCHEME "://", sizeof(SCHEME) + 2)) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
"proxy: " PROXY_FUNCTION ": declining URL %s", url);
return DECLINED;
}
/* Create space for state information */
status = ap_proxy_acquire_connection(PROXY_FUNCTION, &backend, worker,
r->server);
if (status != OK) {
goto cleanup;
}
backend->is_ssl = 0;
/* Step One: Determine Who To Connect To */
status = ap_proxy_determine_connection(p, r, conf, worker, backend,
uri, &url, proxyname, proxyport,
&dummy, 1);
if (status != OK) {
goto cleanup;
}
/* Step Two: Make the Connection */
if (ap_proxy_connect_backend(PROXY_FUNCTION, backend, worker, r->server)) {
ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
"proxy: " PROXY_FUNCTION ": failed to make connection "
"to backend: %s:%u", backend->hostname, backend->port);
status = HTTP_SERVICE_UNAVAILABLE;
goto cleanup;
}
/* Step Three: Process the Request */
if ( ((status = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR)) != OK)
|| ((status = send_headers(r, backend)) != OK)
|| ((status = send_request_body(r, backend)) != OK)
|| ((status = pass_response(r, backend)) != OK)) {
goto cleanup;
}
cleanup:
if (backend) {
backend->close = 1; /* always close the socket */
ap_proxy_release_connection(PROXY_FUNCTION, backend, r->server);
}
return status;
}
static void *create_scgi_config(apr_pool_t *p, char *dummy)
{
scgi_config *conf=apr_palloc(p, sizeof(*conf));
conf->sendfile = NULL;
conf->internal_redirect = -1;
return conf;
}
static void *merge_scgi_config(apr_pool_t *p, void *base_, void *add_)
{
scgi_config *base=base_, *add=add_, *conf=apr_palloc(p, sizeof(*conf));
conf->sendfile = add->sendfile ? add->sendfile: base->sendfile;
conf->internal_redirect = (add->internal_redirect != -1)
? add->internal_redirect
: base->internal_redirect;
return conf;
}
static const char *scgi_set_send_file(cmd_parms *cmd, void *mconfig,
const char *arg)
{
scgi_config *conf=mconfig;
if (!strcasecmp(arg, "Off")) {
conf->sendfile = scgi_sendfile_off;
}
else if (!strcasecmp(arg, "On")) {
conf->sendfile = scgi_sendfile_on;
}
else {
conf->sendfile = arg;
}
return NULL;
}
static const command_rec scgi_cmds[] =
{
AP_INIT_TAKE1("ProxySCGISendfile", scgi_set_send_file, NULL,
RSRC_CONF|ACCESS_CONF,
"The name of the X-Sendfile peudo response header or "
"On or Off"),
AP_INIT_FLAG("ProxySCGIInternalRedirect", ap_set_flag_slot,
(void*)APR_OFFSETOF(scgi_config, internal_redirect),
RSRC_CONF|ACCESS_CONF,
"Off if internal redirect responses should not be accepted"),
{NULL}
};
static void register_hooks(apr_pool_t *p)
{
proxy_hook_scheme_handler(scgi_handler, NULL, NULL, APR_HOOK_FIRST);
proxy_hook_canon_handler(scgi_canon, NULL, NULL, APR_HOOK_FIRST);
APR_OPTIONAL_HOOK(proxy, request_status, scgi_request_status, NULL, NULL,
APR_HOOK_MIDDLE);
}
AP_DECLARE_MODULE(proxy_scgi) = {
STANDARD20_MODULE_STUFF,
create_scgi_config, /* create per-directory config structure */
merge_scgi_config, /* merge per-directory config structures */
NULL, /* create per-server config structure */
NULL, /* merge per-server config structures */
scgi_cmds, /* command table */
register_hooks /* register hooks */
};