/*      $NetBSD: rumpclient.c,v 1.18 2011/01/24 17:47:51 pooka Exp $	*/

/*
 * Copyright (c) 2010, 2011 Antti Kantee.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Client side routines for rump syscall proxy.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD");

#include <sys/param.h>
#include <sys/event.h>
#include <sys/mman.h>
#include <sys/socket.h>

#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>

#include <assert.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <link.h>
#include <poll.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <rump/rumpclient.h>

#define HOSTOPS
int	(*host_socket)(int, int, int);
int	(*host_close)(int);
int	(*host_connect)(int, const struct sockaddr *, socklen_t);
int	(*host_fcntl)(int, int, ...);
int	(*host_poll)(struct pollfd *, nfds_t, int);
ssize_t	(*host_read)(int, void *, size_t);
ssize_t (*host_sendto)(int, const void *, size_t, int,
		       const struct sockaddr *, socklen_t);
int	(*host_setsockopt)(int, int, int, const void *, socklen_t);

int	(*host_kqueue)(void);
int	(*host_kevent)(int, const struct kevent *, size_t,
		       struct kevent *, size_t, const struct timespec *);

#include "sp_common.c"

static struct spclient clispc = {
	.spc_fd = -1,
};

static int kq = -1;
static sigset_t fullset;

static int doconnect(int);
static int handshake_req(struct spclient *, uint32_t *, int, bool);

int didrecon;

static int
send_with_recon(struct spclient *spc, const void *data, size_t dlen)
{
	int rv;

	do {
		rv = dosend(spc, data, dlen);
		if (__predict_false(rv == ENOTCONN || rv == EBADF)) {
			if ((rv = doconnect(1)) != 0)
				continue;
			if ((rv = handshake_req(&clispc, NULL, 0, true)) != 0)
				continue;
			rv = ENOTCONN;
			break;
		}
	} while (__predict_false(rv != 0));

	return rv;
}

static int
cliwaitresp(struct spclient *spc, struct respwait *rw, sigset_t *mask,
	bool keeplock)
{
	uint64_t mygen;
	bool imalive = true;

	pthread_mutex_lock(&spc->spc_mtx);
	if (!keeplock)
		sendunlockl(spc);
	mygen = spc->spc_generation;

	rw->rw_error = 0;
	while (!rw->rw_done && rw->rw_error == 0) {
		if (__predict_false(spc->spc_generation != mygen || !imalive))
			break;

		/* are we free to receive? */
		if (spc->spc_istatus == SPCSTATUS_FREE) {
			struct kevent kev[8];
			int gotresp, dosig, rv, i;

			spc->spc_istatus = SPCSTATUS_BUSY;
			pthread_mutex_unlock(&spc->spc_mtx);

			dosig = 0;
			for (gotresp = 0; !gotresp; ) {
				switch (readframe(spc)) {
				case 0:
					rv = host_kevent(kq, NULL, 0,
					    kev, __arraycount(kev), NULL);

					/*
					 * XXX: don't know how this can
					 * happen (timeout cannot expire
					 * since there isn't one), but
					 * it does happen
					 */
					if (__predict_false(rv == 0))
						continue;

					for (i = 0; i < rv; i++) {
						if (kev[i].filter
						    == EVFILT_SIGNAL)
							dosig++;
					}
					if (dosig)
						goto cleanup;

					continue;
				case -1:
					imalive = false;
					goto cleanup;
				default:
					break;
				}

				switch (spc->spc_hdr.rsp_class) {
				case RUMPSP_RESP:
				case RUMPSP_ERROR:
					kickwaiter(spc);
					gotresp = spc->spc_hdr.rsp_reqno ==
					    rw->rw_reqno;
					break;
				case RUMPSP_REQ:
					handlereq(spc);
					break;
				default:
					/* panic */
					break;
				}
			}

 cleanup:
			pthread_mutex_lock(&spc->spc_mtx);
			if (spc->spc_istatus == SPCSTATUS_WANTED)
				kickall(spc);
			spc->spc_istatus = SPCSTATUS_FREE;

			/* take one for the team */
			if (dosig) {
				pthread_mutex_unlock(&spc->spc_mtx);
				pthread_sigmask(SIG_SETMASK, mask, NULL);
				pthread_sigmask(SIG_SETMASK, &fullset, NULL);
				pthread_mutex_lock(&spc->spc_mtx);
			}
		} else {
			spc->spc_istatus = SPCSTATUS_WANTED;
			pthread_cond_wait(&rw->rw_cv, &spc->spc_mtx);
		}
	}
	TAILQ_REMOVE(&spc->spc_respwait, rw, rw_entries);
	pthread_mutex_unlock(&spc->spc_mtx);
	pthread_cond_destroy(&rw->rw_cv);

	if (spc->spc_generation != mygen || !imalive) {
		return ENOTCONN;
	}
	return rw->rw_error;
}

static int
syscall_req(struct spclient *spc, int sysnum,
	const void *data, size_t dlen, void **resp)
{
	struct rsp_hdr rhdr;
	struct respwait rw;
	sigset_t omask;
	int rv;

	rhdr.rsp_len = sizeof(rhdr) + dlen;
	rhdr.rsp_class = RUMPSP_REQ;
	rhdr.rsp_type = RUMPSP_SYSCALL;
	rhdr.rsp_sysnum = sysnum;

	pthread_sigmask(SIG_SETMASK, &fullset, &omask);
	do {
		putwait(spc, &rw, &rhdr);
		if ((rv = send_with_recon(spc, &rhdr, sizeof(rhdr))) != 0) {
			unputwait(spc, &rw);
			continue;
		}
		if ((rv = send_with_recon(spc, data, dlen)) != 0) {
			unputwait(spc, &rw);
			continue;
		}

		rv = cliwaitresp(spc, &rw, &omask, false);
	} while (rv == ENOTCONN || rv == EAGAIN);
	pthread_sigmask(SIG_SETMASK, &omask, NULL);

	*resp = rw.rw_data;
	return rv;
}

static int
handshake_req(struct spclient *spc, uint32_t *auth, int cancel, bool haslock)
{
	struct handshake_fork rf;
	struct rsp_hdr rhdr;
	struct respwait rw;
	sigset_t omask;
	int rv;

	/* performs server handshake */
	rhdr.rsp_len = sizeof(rhdr) + (auth ? sizeof(rf) : 0);
	rhdr.rsp_class = RUMPSP_REQ;
	rhdr.rsp_type = RUMPSP_HANDSHAKE;
	if (auth)
		rhdr.rsp_handshake = HANDSHAKE_FORK;
	else
		rhdr.rsp_handshake = HANDSHAKE_GUEST;

	pthread_sigmask(SIG_SETMASK, &fullset, &omask);
	if (haslock)
		putwait_locked(spc, &rw, &rhdr);
	else
		putwait(spc, &rw, &rhdr);
	rv = dosend(spc, &rhdr, sizeof(rhdr));
	if (auth) {
		memcpy(rf.rf_auth, auth, AUTHLEN*sizeof(*auth));
		rf.rf_cancel = cancel;
		rv = send_with_recon(spc, &rf, sizeof(rf));
	}
	if (rv || cancel) {
		if (haslock)
			unputwait_locked(spc, &rw);
		else
			unputwait(spc, &rw);
		if (cancel) {
			pthread_sigmask(SIG_SETMASK, &omask, NULL);
			return rv;
		}
	} else {
		rv = cliwaitresp(spc, &rw, &omask, haslock);
	}
	pthread_sigmask(SIG_SETMASK, &omask, NULL);
	if (rv)
		return rv;

	rv = *(int *)rw.rw_data;
	free(rw.rw_data);

	return rv;
}

static int
prefork_req(struct spclient *spc, void **resp)
{
	struct rsp_hdr rhdr;
	struct respwait rw;
	sigset_t omask;
	int rv;

	rhdr.rsp_len = sizeof(rhdr);
	rhdr.rsp_class = RUMPSP_REQ;
	rhdr.rsp_type = RUMPSP_PREFORK;
	rhdr.rsp_error = 0;

	pthread_sigmask(SIG_SETMASK, &fullset, &omask);
	do {
		putwait(spc, &rw, &rhdr);
		rv = send_with_recon(spc, &rhdr, sizeof(rhdr));
		if (rv != 0) {
			unputwait(spc, &rw);
			continue;
		}

		rv = cliwaitresp(spc, &rw, &omask, false);
	} while (rv == ENOTCONN || rv == EAGAIN);
	pthread_sigmask(SIG_SETMASK, &omask, NULL);

	*resp = rw.rw_data;
	return rv;
}

/*
 * prevent response code from deadlocking with reconnect code
 */
static int
resp_sendlock(struct spclient *spc)
{
	int rv = 0;

	pthread_mutex_lock(&spc->spc_mtx);
	while (spc->spc_ostatus != SPCSTATUS_FREE) {
		if (__predict_false(spc->spc_reconnecting)) {
			rv = EBUSY;
			goto out;
		}
		spc->spc_ostatus = SPCSTATUS_WANTED;
		pthread_cond_wait(&spc->spc_cv, &spc->spc_mtx);
	}
	spc->spc_ostatus = SPCSTATUS_BUSY;

 out:
	pthread_mutex_unlock(&spc->spc_mtx);
	return rv;
}

static void
send_copyin_resp(struct spclient *spc, uint64_t reqno, void *data, size_t dlen,
	int wantstr)
{
	struct rsp_hdr rhdr;

	if (wantstr)
		dlen = MIN(dlen, strlen(data)+1);

	rhdr.rsp_len = sizeof(rhdr) + dlen;
	rhdr.rsp_reqno = reqno;
	rhdr.rsp_class = RUMPSP_RESP;
	rhdr.rsp_type = RUMPSP_COPYIN;
	rhdr.rsp_sysnum = 0;

	if (resp_sendlock(spc) != 0)
		return;
	(void)dosend(spc, &rhdr, sizeof(rhdr));
	(void)dosend(spc, data, dlen);
	sendunlock(spc);
}

static void
send_anonmmap_resp(struct spclient *spc, uint64_t reqno, void *addr)
{
	struct rsp_hdr rhdr;

	rhdr.rsp_len = sizeof(rhdr) + sizeof(addr);
	rhdr.rsp_reqno = reqno;
	rhdr.rsp_class = RUMPSP_RESP;
	rhdr.rsp_type = RUMPSP_ANONMMAP;
	rhdr.rsp_sysnum = 0;

	if (resp_sendlock(spc) != 0)
		return;
	(void)dosend(spc, &rhdr, sizeof(rhdr));
	(void)dosend(spc, &addr, sizeof(addr));
	sendunlock(spc);
}

int
rumpclient_syscall(int sysnum, const void *data, size_t dlen,
	register_t *retval)
{
	struct rsp_sysresp *resp;
	void *rdata;
	int rv;

	DPRINTF(("rumpsp syscall_req: syscall %d with %p/%zu\n",
	    sysnum, data, dlen));

	rv = syscall_req(&clispc, sysnum, data, dlen, &rdata);
	if (rv)
		return rv;

	resp = rdata;
	DPRINTF(("rumpsp syscall_resp: syscall %d error %d, rv: %d/%d\n",
	    sysnum, rv, resp->rsys_retval[0], resp->rsys_retval[1]));

	memcpy(retval, &resp->rsys_retval, sizeof(resp->rsys_retval));
	rv = resp->rsys_error;
	free(rdata);

	return rv;
}

static void
handlereq(struct spclient *spc)
{
	struct rsp_copydata *copydata;
	struct rsp_hdr *rhdr = &spc->spc_hdr;
	void *mapaddr;
	size_t maplen;
	int reqtype = spc->spc_hdr.rsp_type;

	switch (reqtype) {
	case RUMPSP_COPYIN:
	case RUMPSP_COPYINSTR:
		/*LINTED*/
		copydata = (struct rsp_copydata *)spc->spc_buf;
		DPRINTF(("rump_sp handlereq: copyin request: %p/%zu\n",
		    copydata->rcp_addr, copydata->rcp_len));
		send_copyin_resp(spc, spc->spc_hdr.rsp_reqno,
		    copydata->rcp_addr, copydata->rcp_len,
		    reqtype == RUMPSP_COPYINSTR);
		break;
	case RUMPSP_COPYOUT:
	case RUMPSP_COPYOUTSTR:
		/*LINTED*/
		copydata = (struct rsp_copydata *)spc->spc_buf;
		DPRINTF(("rump_sp handlereq: copyout request: %p/%zu\n",
		    copydata->rcp_addr, copydata->rcp_len));
		/*LINTED*/
		memcpy(copydata->rcp_addr, copydata->rcp_data,
		    copydata->rcp_len);
		break;
	case RUMPSP_ANONMMAP:
		/*LINTED*/
		maplen = *(size_t *)spc->spc_buf;
		mapaddr = mmap(NULL, maplen, PROT_READ|PROT_WRITE,
		    MAP_ANON, -1, 0);
		if (mapaddr == MAP_FAILED)
			mapaddr = NULL;
		DPRINTF(("rump_sp handlereq: anonmmap: %p\n", mapaddr));
		send_anonmmap_resp(spc, spc->spc_hdr.rsp_reqno, mapaddr);
		break;
	case RUMPSP_RAISE:
		DPRINTF(("rump_sp handlereq: raise sig %d\n", rhdr->rsp_signo));
		raise((int)rhdr->rsp_signo);
		/*
		 * We most likely have signals blocked, but the signal
		 * will be handled soon enough when we return.
		 */
		break;
	default:
		printf("PANIC: INVALID TYPE %d\n", reqtype);
		abort();
		break;
	}

	spcfreebuf(spc);
}

static unsigned ptab_idx;
static struct sockaddr *serv_sa;

static int
doconnect(int retry)
{
	time_t prevreconmsg;
	unsigned reconretries;
	struct respwait rw;
	struct rsp_hdr rhdr;
	struct kevent kev[NSIG+1];
	char banner[MAXBANNER];
	struct pollfd pfd;
	int s, error, flags, i;
	ssize_t n;

	if (kq != -1)
		host_close(kq);
	kq = -1;

	prevreconmsg = 0;
	reconretries = 0;

 again:
	if (clispc.spc_fd != -1)
		host_close(clispc.spc_fd);
	clispc.spc_fd = -1;

	/*
	 * for reconnect, gate everyone out of the receiver code
	 */
	putwait_locked(&clispc, &rw, &rhdr);

	pthread_mutex_lock(&clispc.spc_mtx);
	clispc.spc_reconnecting = 1;
	pthread_cond_broadcast(&clispc.spc_cv);
	clispc.spc_generation++;
	while (clispc.spc_istatus != SPCSTATUS_FREE) {
		clispc.spc_istatus = SPCSTATUS_WANTED;
		pthread_cond_wait(&rw.rw_cv, &clispc.spc_mtx);
	}
	kickall(&clispc);

	/*
	 * we can release it already since we hold the
	 * send lock during reconnect
	 * XXX: assert it
	 */
	clispc.spc_istatus = SPCSTATUS_FREE;
	pthread_mutex_unlock(&clispc.spc_mtx);
	unputwait_locked(&clispc, &rw);

	free(clispc.spc_buf);
	clispc.spc_off = 0;

	s = host_socket(parsetab[ptab_idx].domain, SOCK_STREAM, 0);
	if (s == -1)
		return -1;

	pfd.fd = s;
	pfd.events = POLLIN;
	while (host_connect(s, serv_sa, (socklen_t)serv_sa->sa_len) == -1) {
		if (errno == EINTR)
			continue;
		if (!retry) {
			error = errno;
			fprintf(stderr, "rump_sp: client connect failed: %s\n",
			    strerror(errno));
			errno = error;
			return -1;
		}

		if (prevreconmsg == 0) {
			fprintf(stderr, "rump_sp: connection to kernel lost, "
			    "trying to reconnect ...\n");
			prevreconmsg = time(NULL);
		}
		if (time(NULL) - prevreconmsg > 120) {
			fprintf(stderr, "rump_sp: still trying to "
			    "reconnect ...\n");
			prevreconmsg = time(NULL);
		}

		/* adhoc backoff timer */
		if (reconretries++ < 10) {
			usleep(100000 * reconretries);
		} else {
			sleep(MIN(10, reconretries-9));
		}
		goto again;
	}

	if ((error = parsetab[ptab_idx].connhook(s)) != 0) {
		error = errno;
		fprintf(stderr, "rump_sp: connect hook failed\n");
		errno = error;
		return -1;
	}

	if ((n = host_read(s, banner, sizeof(banner)-1)) < 0) {
		error = errno;
		fprintf(stderr, "rump_sp: failed to read banner\n");
		errno = error;
		return -1;
	}

	if (banner[n-1] != '\n') {
		fprintf(stderr, "rump_sp: invalid banner\n");
		errno = EINVAL;
		return -1;
	}
	banner[n] = '\0';
	/* parse the banner some day */

	flags = host_fcntl(s, F_GETFL, 0);
	if (host_fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1) {
		fprintf(stderr, "rump_sp: socket fd NONBLOCK: %s\n",
		    strerror(errno));
		errno = EINVAL;
		return -1;
	}
	clispc.spc_fd = s;
	clispc.spc_state = SPCSTATE_RUNNING;
	clispc.spc_reconnecting = 0;

	if (prevreconmsg) {
		fprintf(stderr, "rump_sp: reconnected!\n");
	}

	/* setup kqueue, we want all signals and the fd */
	if ((kq = host_kqueue()) == -1) {
		error = errno;
		fprintf(stderr, "rump_sp: cannot setup kqueue");
		errno = error;
		return -1;
	}

	for (i = 0; i < NSIG; i++) {
		EV_SET(&kev[i], i+1, EVFILT_SIGNAL, EV_ADD|EV_ENABLE, 0, 0, 0);
	}
	EV_SET(&kev[NSIG], clispc.spc_fd,
	    EVFILT_READ, EV_ADD|EV_ENABLE, 0, 0, 0);
	if (host_kevent(kq, kev, NSIG+1, NULL, 0, NULL) == -1) {
		error = errno;
		fprintf(stderr, "rump_sp: kevent() failed");
		errno = error;
		return -1;
	}

	return 0;
}

static int
doinit(void)
{

	TAILQ_INIT(&clispc.spc_respwait);
	pthread_mutex_init(&clispc.spc_mtx, NULL);
	pthread_cond_init(&clispc.spc_cv, NULL);

	return 0;
}

void *(*rumpclient_dlsym)(void *, const char *);

int
rumpclient_init()
{
	char *p;
	int error;

	/* dlsym overrided by rumphijack? */
	if (!rumpclient_dlsym)
		rumpclient_dlsym = dlsym;

	/*
	 * sag mir, wo die symbol sind.  zogen fort, der krieg beginnt.
	 * wann wird man je verstehen?  wann wird man je verstehen?
	 */
#define FINDSYM2(_name_,_syscall_)					\
	if ((host_##_name_ = rumpclient_dlsym(RTLD_NEXT,		\
	    #_syscall_)) == NULL)					\
		/* host_##_name_ = _syscall_ */;
#define FINDSYM(_name_) FINDSYM2(_name_,_name_)
	FINDSYM2(socket,__socket30);
	FINDSYM(close);
	FINDSYM(connect);
	FINDSYM(fcntl);
	FINDSYM(poll);
	FINDSYM(read);
	FINDSYM(sendto);
	FINDSYM(setsockopt);
	FINDSYM(kqueue);
	FINDSYM(kevent);
#undef	FINDSYM
#undef	FINDSY2

	if ((p = getenv("RUMP_SERVER")) == NULL) {
		errno = ENOENT;
		return -1;
	}

	if ((error = parseurl(p, &serv_sa, &ptab_idx, 0)) != 0) {
		errno = error;
		return -1;
	}

	if (doinit() == -1)
		return -1;
	if (doconnect(0) == -1)
		return -1;

	error = handshake_req(&clispc, NULL, 0, false);
	if (error) {
		pthread_mutex_destroy(&clispc.spc_mtx);
		pthread_cond_destroy(&clispc.spc_cv);
		if (clispc.spc_fd != -1)
			host_close(clispc.spc_fd);
		errno = error;
		return -1;
	}

	sigfillset(&fullset);
	return 0;
}

struct rumpclient_fork {
	uint32_t fork_auth[AUTHLEN];
};

struct rumpclient_fork *
rumpclient_prefork(void)
{
	struct rumpclient_fork *rpf;
	void *resp;
	int rv;

	rpf = malloc(sizeof(*rpf));
	if (rpf == NULL)
		return NULL;

	if ((rv = prefork_req(&clispc, &resp)) != 0) {
		free(rpf);
		errno = rv;
		return NULL;
	}

	memcpy(rpf->fork_auth, resp, sizeof(rpf->fork_auth));
	free(resp);

	return rpf;
}

int
rumpclient_fork_init(struct rumpclient_fork *rpf)
{
	int error;

	memset(&clispc, 0, sizeof(clispc));
	clispc.spc_fd = -1;
	kq = -1;

	if (doinit() == -1)
		return -1;
	if (doconnect(1) == -1)
		return -1;

	error = handshake_req(&clispc, rpf->fork_auth, 0, false);
	if (error) {
		pthread_mutex_destroy(&clispc.spc_mtx);
		pthread_cond_destroy(&clispc.spc_cv);
		errno = error;
		return -1;
	}

	return 0;
}