/*	$OpenBSD: server_fcgi.c,v 1.34 2014/08/21 19:23:10 chrisz Exp $	*/

/*
 * Copyright (c) 2014 Florian Obser <florian@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/tree.h>
#include <sys/hash.h>

#include <net/if.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>

#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <err.h>
#include <event.h>

#include "httpd.h"
#include "http.h"

#define FCGI_PADDING_SIZE	 255
#define FCGI_RECORD_SIZE	 \
    (sizeof(struct fcgi_record_header) + FCGI_CONTENT_SIZE + FCGI_PADDING_SIZE)

#define FCGI_BEGIN_REQUEST	 1
#define FCGI_ABORT_REQUEST	 2
#define FCGI_END_REQUEST	 3
#define FCGI_PARAMS		 4
#define FCGI_STDIN		 5
#define FCGI_STDOUT		 6
#define FCGI_STDERR		 7
#define FCGI_DATA		 8
#define FCGI_GET_VALUES		 9
#define FCGI_GET_VALUES_RESULT	10
#define FCGI_UNKNOWN_TYPE	11
#define FCGI_MAXTYPE		(FCGI_UNKNOWN_TYPE)

#define FCGI_RESPONDER		 1

struct fcgi_record_header {
	uint8_t		version;
	uint8_t		type;
	uint16_t	id;
	uint16_t	content_len;
	uint8_t		padding_len;
	uint8_t		reserved;
} __packed;

struct fcgi_begin_request_body {
	uint16_t	role;
	uint8_t		flags;
	uint8_t		reserved[5];
} __packed;

struct server_fcgi_param {
	int		total_len;
	uint8_t		buf[FCGI_RECORD_SIZE];
};

int	server_fcgi_header(struct client *, u_int);
void	server_fcgi_read(struct bufferevent *, void *);
int	server_fcgi_writeheader(struct client *, struct kv *, void *);
int	fcgi_add_param(struct server_fcgi_param *, const char *, const char *,
	    struct client *);
int	get_status(struct evbuffer *);

int
server_fcgi(struct httpd *env, struct client *clt)
{
	struct server_fcgi_param	 param;
	struct server_config		*srv_conf = clt->clt_srv_conf;
	struct http_descriptor		*desc = clt->clt_desc;
	struct fcgi_record_header	*h;
	struct fcgi_begin_request_body	*begin;
	char				 hbuf[MAXHOSTNAMELEN];
	size_t				 scriptlen;
	int				 pathlen;
	int				 fd = -1, ret;
	const char			*errstr = NULL;
	char				*str, *p, *script = NULL;

	if (srv_conf->socket[0] == ':') {
		struct sockaddr_storage	 ss;
		in_port_t		 port;

		p = srv_conf->socket + 1;

		port = strtonum(p, 0, 0xffff, &errstr);
		if (errstr != NULL) {
			log_warn("%s: strtonum %s, %s", __func__, p, errstr);
			goto fail;
		}
		memset(&ss, 0, sizeof(ss));
		ss.ss_family = AF_INET;
		((struct sockaddr_in *)
		    &ss)->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
		port = htons(port);

		if ((fd = server_socket_connect(&ss, port, srv_conf)) == -1)
			goto fail;
	} else {
		struct sockaddr_un	 sun;
		size_t			 len;
	
		if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
			goto fail;

		memset(&sun, 0, sizeof(sun));
		sun.sun_family = AF_UNIX;
		len = strlcpy(sun.sun_path,
		    srv_conf->socket, sizeof(sun.sun_path));
		if (len >= sizeof(sun.sun_path)) {
			errstr = "socket path to long";
			goto fail;
		}
		sun.sun_len = len;

		if (connect(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1)
			goto fail;
	}

	socket_set_blockmode(fd, BM_NONBLOCK);

	memset(hbuf, 0, sizeof(hbuf));
	clt->clt_fcgi_state = FCGI_READ_HEADER;
	clt->clt_fcgi_toread = sizeof(struct fcgi_record_header);

	if (clt->clt_srvevb != NULL)
		evbuffer_free(clt->clt_srvevb);

	clt->clt_srvevb = evbuffer_new();
	if (clt->clt_srvevb == NULL) {
		errstr = "failed to allocate evbuffer";
		goto fail;
	}

	clt->clt_fd = fd;
	if (clt->clt_srvbev != NULL)
		bufferevent_free(clt->clt_srvbev);

	clt->clt_srvbev = bufferevent_new(fd, server_fcgi_read,
	    NULL, server_file_error, clt);
	if (clt->clt_srvbev == NULL) {
		errstr = "failed to allocate fcgi buffer event";
		goto fail;
	}

	memset(&param, 0, sizeof(param));

	h = (struct fcgi_record_header *)&param.buf;
	h->version = 1;
	h->type = FCGI_BEGIN_REQUEST;
	h->id = htons(1);
	h->content_len = htons(sizeof(struct fcgi_begin_request_body));
	h->padding_len = 0;

	begin = (struct fcgi_begin_request_body *)&param.buf[sizeof(struct
	    fcgi_record_header)];
	begin->role = htons(FCGI_RESPONDER);

	bufferevent_write(clt->clt_srvbev, &param.buf,
	    sizeof(struct fcgi_record_header) +
	    sizeof(struct fcgi_begin_request_body));

	h->type = FCGI_PARAMS;
	h->content_len = param.total_len = 0;

	if ((pathlen = asprintf(&script, "%s%s", srv_conf->root,
	    desc->http_path_alias != NULL ?
	    desc->http_path_alias : desc->http_path)) == -1) {
		errstr = "failed to get script name";
		goto fail;
	}

	scriptlen = path_info(script);
	/*
	 * no part of root should show up in PATH_INFO.
	 * therefore scriptlen should be >= strlen(root)
	 */
	if (scriptlen < strlen(srv_conf->root))
		scriptlen = strlen(srv_conf->root);
	if ((int)scriptlen < pathlen) {
		if (fcgi_add_param(&param, "PATH_INFO",
		    script + scriptlen, clt) == -1) {
			errstr = "failed to encode param";
			goto fail;
		}
		script[scriptlen] = '\0';
	}

	if (fcgi_add_param(&param, "SCRIPT_NAME",
	    script + strlen(srv_conf->root), clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}
	if (fcgi_add_param(&param, "SCRIPT_FILENAME", script, clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (desc->http_query)
		if (fcgi_add_param(&param, "QUERY_STRING", desc->http_query,
		    clt) == -1) {
			errstr = "failed to encode param";
			goto fail;
		}

	if (fcgi_add_param(&param, "DOCUMENT_ROOT", srv_conf->root,
	    clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}
	if (fcgi_add_param(&param, "DOCUMENT_URI", desc->http_path,
	    clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}
	if (fcgi_add_param(&param, "GATEWAY_INTERFACE", "CGI/1.1",
	    clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	/* Add HTTP_* headers */
	if (server_headers(clt, server_fcgi_writeheader, &param) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (srv_conf->flags & SRVFLAG_SSL)
		if (fcgi_add_param(&param, "HTTPS", "on", clt) == -1) {
			errstr = "failed to encode param";
			goto fail;
		}

	(void)print_host(&clt->clt_ss, hbuf, sizeof(hbuf));
	if (fcgi_add_param(&param, "REMOTE_ADDR", hbuf, clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	(void)snprintf(hbuf, sizeof(hbuf), "%d", ntohs(clt->clt_port));
	if (fcgi_add_param(&param, "REMOTE_PORT", hbuf, clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (fcgi_add_param(&param, "REQUEST_METHOD",
	    server_httpmethod_byid(desc->http_method), clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (!desc->http_query) {
		if (fcgi_add_param(&param, "REQUEST_URI", desc->http_path,
		    clt) == -1) {
			errstr = "failed to encode param";
			goto fail;
		}
	} else if (asprintf(&str, "%s?%s", desc->http_path,
	    desc->http_query) != -1) {
		ret = fcgi_add_param(&param, "REQUEST_URI", str, clt);
		free(str);
		if (ret == -1) {
			errstr = "failed to encode param";
			goto fail;
		}
	}

	(void)print_host(&clt->clt_srv_ss, hbuf, sizeof(hbuf));
	if (fcgi_add_param(&param, "SERVER_ADDR", hbuf, clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	(void)snprintf(hbuf, sizeof(hbuf), "%d",
	    ntohs(server_socket_getport(&clt->clt_srv_ss)));
	if (fcgi_add_param(&param, "SERVER_PORT", hbuf, clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (fcgi_add_param(&param, "SERVER_NAME", srv_conf->name,
	    clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (fcgi_add_param(&param, "SERVER_PROTOCOL", desc->http_version,
	    clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (fcgi_add_param(&param, "SERVER_SOFTWARE", HTTPD_SERVERNAME,
	    clt) == -1) {
		errstr = "failed to encode param";
		goto fail;
	}

	if (param.total_len != 0) {	/* send last params record */
		bufferevent_write(clt->clt_srvbev, &param.buf,
		    sizeof(struct fcgi_record_header) +
		    ntohs(h->content_len));
	}

	/* send "no more params" message */
	h->content_len = 0;
	bufferevent_write(clt->clt_srvbev, &param.buf,
	    sizeof(struct fcgi_record_header));

	bufferevent_settimeout(clt->clt_srvbev,
	    srv_conf->timeout.tv_sec, srv_conf->timeout.tv_sec);
	bufferevent_enable(clt->clt_srvbev, EV_READ|EV_WRITE);
	if (clt->clt_toread != 0) {
		server_read_httpcontent(clt->clt_bev, clt);
		bufferevent_enable(clt->clt_bev, EV_READ);
	} else {
		bufferevent_disable(clt->clt_bev, EV_READ);
		fcgi_add_stdin(clt, NULL);
	}

	/*
	 * persist is not supported yet because we don't get the
	 * Content-Length from slowcgi and don't support chunked encoding.
	 */
	clt->clt_persist = 0;
	clt->clt_done = 0;

	free(script);
	return (0);
 fail:
	free(script);
	if (errstr == NULL)
		errstr = strerror(errno);
	server_abort_http(clt, 500, errstr);
	return (-1);
}

int
fcgi_add_stdin(struct client *clt, struct evbuffer *evbuf)
{
	struct fcgi_record_header	h;

	memset(&h, 0, sizeof(h));
	h.version = 1;
	h.type = FCGI_STDIN;
	h.id = htons(1);
	h.padding_len = 0;

	if (evbuf == NULL) {
		h.content_len = 0;
		return bufferevent_write(clt->clt_srvbev, &h,
		    sizeof(struct fcgi_record_header));
	} else {
		h.content_len = htons(EVBUFFER_LENGTH(evbuf));
		if (bufferevent_write(clt->clt_srvbev, &h,
		    sizeof(struct fcgi_record_header)) == -1)
			return -1;
		return bufferevent_write_buffer(clt->clt_srvbev, evbuf);
	}
	return (0);
}

int
fcgi_add_param(struct server_fcgi_param *p, const char *key,
    const char *val, struct client *clt)
{
	struct fcgi_record_header	*h;
	int				 len = 0;
	int				 key_len = strlen(key);
	int				 val_len = strlen(val);
	uint8_t				*param;

	len += key_len + val_len;
	len += key_len > 127 ? 4 : 1;
	len += val_len > 127 ? 4 : 1;

	DPRINTF("%s: %s[%d] => %s[%d], total_len: %d", __func__, key, key_len,
	    val, val_len, p->total_len);

	if (len > FCGI_CONTENT_SIZE)
		return (-1);

	if (p->total_len + len > FCGI_CONTENT_SIZE) {
		bufferevent_write(clt->clt_srvbev, p->buf,
		    sizeof(struct fcgi_record_header) + p->total_len);
		p->total_len = 0;
	}

	h = (struct fcgi_record_header *)p->buf;
	param = p->buf + sizeof(*h) + p->total_len;

	if (key_len > 127) {
		*param++ = ((key_len >> 24) & 0xff) | 0x80;
		*param++ = ((key_len >> 16) & 0xff);
		*param++ = ((key_len >> 8) & 0xff);
		*param++ = (key_len & 0xff);
	} else
		*param++ = key_len;

	if (val_len > 127) {
		*param++ = ((val_len >> 24) & 0xff) | 0x80;
		*param++ = ((val_len >> 16) & 0xff);
		*param++ = ((val_len >> 8) & 0xff);
		*param++ = (val_len & 0xff);
	} else
		*param++ = val_len;

	memcpy(param, key, key_len);
	param += key_len;
	memcpy(param, val, val_len);

	p->total_len += len;

	h->content_len = htons(p->total_len);
	return (0);
}

void
server_fcgi_read(struct bufferevent *bev, void *arg)
{
	uint8_t				 buf[FCGI_RECORD_SIZE];
	struct client			*clt = (struct client *) arg;
	struct fcgi_record_header	*h;
	size_t				 len;
	char				*ptr;

	do {
		len = bufferevent_read(bev, &buf, clt->clt_fcgi_toread);
		/* XXX error handling */
		evbuffer_add(clt->clt_srvevb, &buf, len);
		clt->clt_fcgi_toread -= len;
		DPRINTF("%s: len: %lu toread: %d state: %d", __func__, len,
		    clt->clt_fcgi_toread, clt->clt_fcgi_state);

		if (clt->clt_fcgi_toread != 0)
			return;

		switch (clt->clt_fcgi_state) {
		case FCGI_READ_HEADER:
			clt->clt_fcgi_state = FCGI_READ_CONTENT;
			h = (struct fcgi_record_header *)
			    EVBUFFER_DATA(clt->clt_srvevb);
			DPRINTF("%s: record header: version %d type %d id %d "
			    "content len %d padding %d", __func__,
			     h->version, h->type, ntohs(h->id),
			     ntohs(h->content_len), h->padding_len);
			clt->clt_fcgi_type = h->type;
			clt->clt_fcgi_toread = ntohs(h->content_len);
			clt->clt_fcgi_padding_len = h->padding_len;
			evbuffer_drain(clt->clt_srvevb,
			    EVBUFFER_LENGTH(clt->clt_srvevb));
			if (clt->clt_fcgi_toread != 0)
				break;
			else if (clt->clt_fcgi_type == FCGI_STDOUT &&
			    !clt->clt_chunk) {
				server_abort_http(clt, 500, "empty stdout");
				return;
			}

			/* fallthrough if content_len == 0 */
		case FCGI_READ_CONTENT:
			if (clt->clt_fcgi_type == FCGI_STDERR &&
			    EVBUFFER_LENGTH(clt->clt_srvevb) > 0) {
				if ((ptr = get_string(
				    EVBUFFER_DATA(clt->clt_srvevb),
				    EVBUFFER_LENGTH(clt->clt_srvevb)))
				    != NULL) {
					server_sendlog(clt->clt_srv_conf,
					    IMSG_LOG_ERROR, "%s", ptr);
					free(ptr);
				}
			}
			if (clt->clt_fcgi_type == FCGI_STDOUT &&
			    EVBUFFER_LENGTH(clt->clt_srvevb) > 0) {
				if (++clt->clt_chunk == 1)
					server_fcgi_header(clt,
					    get_status(clt->clt_srvevb));
				server_bufferevent_write_buffer(clt,
				    clt->clt_srvevb);
			}
			evbuffer_drain(clt->clt_srvevb,
			    EVBUFFER_LENGTH(clt->clt_srvevb));
			if (!clt->clt_fcgi_padding_len) {
				clt->clt_fcgi_state = FCGI_READ_HEADER;
				clt->clt_fcgi_toread =
				    sizeof(struct fcgi_record_header);
			} else {
				clt->clt_fcgi_state = FCGI_READ_PADDING;
				clt->clt_fcgi_toread =
				    clt->clt_fcgi_padding_len;
			}
			break;
		case FCGI_READ_PADDING:
			evbuffer_drain(clt->clt_srvevb,
			    EVBUFFER_LENGTH(clt->clt_srvevb));
			clt->clt_fcgi_state = FCGI_READ_HEADER;
			clt->clt_fcgi_toread =
			    sizeof(struct fcgi_record_header);
			break;
		}
	} while (len > 0);
}

int
server_fcgi_header(struct client *clt, u_int code)
{
	struct http_descriptor	*desc = clt->clt_desc;
	const char		*error;
	char			 tmbuf[32];

	if (desc == NULL || (error = server_httperror_byid(code)) == NULL)
		return (-1);

	if (server_log_http(clt, code, 0) == -1)
		return (-1);

	kv_purge(&desc->http_headers);

	/* Add error codes */
	if (kv_setkey(&desc->http_pathquery, "%lu", code) == -1 ||
	    kv_set(&desc->http_pathquery, "%s", error) == -1)
		return (-1);

	/* Add headers */
	if (kv_add(&desc->http_headers, "Server", HTTPD_SERVERNAME) == NULL)
		return (-1);

	/* Is it a persistent connection? */
	if (clt->clt_persist) {
		if (kv_add(&desc->http_headers,
		    "Connection", "keep-alive") == NULL)
			return (-1);
	} else if (kv_add(&desc->http_headers, "Connection", "close") == NULL)
		return (-1);

	/* Date header is mandatory and should be added as late as possible */
	if (server_http_time(time(NULL), tmbuf, sizeof(tmbuf)) <= 0 ||
	    kv_add(&desc->http_headers, "Date", tmbuf) == NULL)
		return (-1);

	/* Write initial header (fcgi might append more) */
	if (server_writeresponse_http(clt) == -1 ||
	    server_bufferevent_print(clt, "\r\n") == -1 ||
	    server_headers(clt, server_writeheader_http, NULL) == -1)
		return (-1);

	return (0);
}

int
server_fcgi_writeheader(struct client *clt, struct kv *hdr, void *arg)
{
	struct server_fcgi_param	*param = arg;
	char				*val, *name, *p;
	const char			*key;
	int				 ret;

	if (hdr->kv_flags & KV_FLAG_INVALID)
		return (0);

	/* The key might have been updated in the parent */
	if (hdr->kv_parent != NULL && hdr->kv_parent->kv_key != NULL)
		key = hdr->kv_parent->kv_key;
	else
		key = hdr->kv_key;

	val = hdr->kv_value;

	if (strcasecmp(key, "Content-Length") == 0 ||
	    strcasecmp(key, "Content-Type") == 0) {
		if ((name = strdup(key)) == NULL)
			return (-1);
	} else {
		if (asprintf(&name, "HTTP_%s", key) == -1)
			return (-1);
	}

	for (p = name; *p != '\0'; p++) {
		if (isalpha((unsigned char)*p))
			*p = toupper((unsigned char)*p);
		else
			*p = '_';
	}

	ret = fcgi_add_param(param, name, val, clt);
	free(name);

	return (ret);
}

int
get_status(struct evbuffer *bev)
{
	int code;
	char *statusline, *tok;
	const char *errstr;

	/* XXX This is a hack. We need to parse the response header. */
	code = 200;
	if (strncmp(EVBUFFER_DATA(bev), "Status: ", strlen("Status: ")) == 0) {
		statusline = get_string(EVBUFFER_DATA(bev),
		    EVBUFFER_LENGTH(bev));
		if (strtok(statusline, " ") != NULL) {
			if ((tok = strtok(NULL, " ")) != NULL) {
				code = (int) strtonum(tok, 100, 600, &errstr);
				if (errstr != NULL || server_httperror_byid(
				   code) == NULL)
					code = 200;
			}
		}
		free(statusline);
	}
	return code;
}