syscalls.c

来自「kaffe Java 解释器语言,源码,Java的子集系统,开放源代码」· C语言 代码 · 共 926 行 · 第 1/2 页

 * Threaded socket accept.
 */
int
jthreadedAccept(int fd, struct sockaddr* addr, int* len, 
		int timeout, int* out)
{
	/* absolute time at which time out is reached */
#if defined(SO_RCVTIMEO)
	int ret;
	struct timeval old_tv;
	struct timeval new_tv;
	int old_tv_sz = sizeof (old_tv);
	getsockopt (fd, SOL_SOCKET, SO_RCVTIMEO, &old_tv, &old_tv_sz);
	new_tv.tv_sec = 0;
	/* Guessed according to the former behaviour of jthreadedAccept
	 * Even if it is wrong
	 */
	if (timeout == NOTIMEOUT)
		new_tv.tv_usec = 0;
	else
		new_tv.tv_usec = timeout*1000;
	ret = setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &new_tv, sizeof(new_tv));
        if (!ret) {
		ret = accept (fd, addr, len);
		setsockopt (fd, SOL_SOCKET, SO_RCVTIMEO, &old_tv, sizeof (old_tv));
		if( ret < 0 )
		{
		    switch( errno )
		    {
		    case EAGAIN:
			errno = ETIMEDOUT;
			break;
		    }
		}
	}
	SET_RETURN_OUT(ret, out, ret)
	return ret;
#else
	int r=-1, ret;	
	ret = waitForTimeout(fd,timeout);
	if (ret > 0) {
		r = accept(fd,addr,len);
		SET_RETURN_OUT(r, out, r)
		return (r);
	}
	else {
		errno = ETIMEDOUT;
		r = -1;
	}
	
	SET_RETURN_OUT(r, out, r)
	return (r);
#endif
}

/*
 * Threaded read with timeout
 */
int
jthreadedTimedRead(int fd, void* buf, size_t len, int timeout, ssize_t *out)
{
	ssize_t r = -1;
	/* absolute time at which timeout is reached */
	int ret;
	
	ret = waitForTimeout(fd,timeout);
	if (ret > 0) {
		r = read(fd, buf, len);
	}
	
	SET_RETURN_OUT(r, out, r)
	return (r);
}

/*
 * Threaded write with timeout
 */
int
jthreadedTimedWrite(int fd, const void* buf, size_t len, int timeout, ssize_t *out)
{
	ssize_t r = -1;
	/* absolute time at which timeout is reached */
	int ret;
	
	ret = waitForWritable(fd,timeout);
	if (ret > 0) {
		r = write(fd, buf, len);
	}
	
	SET_RETURN_OUT(r, out, r)
	return (r);
}

/*
 * Threaded read with no time out
 */
int
jthreadedRead(int fd, void* buf, size_t len, ssize_t *out)
{
	ssize_t r = -1;

	r = read(fd, buf, len);
	SET_RETURN_OUT(r, out, r);
	return (r);
}

/*
 * Threaded write
 */
int
jthreadedWrite(int fd, const void* buf, size_t len, ssize_t *out)
{
	ssize_t r = 1;
	const void* ptr;

	ptr = buf;

	while (len > 0 && r > 0) {
		r = (ssize_t)write(fd, ptr, len);
		if (r >= 0) {
			ptr += r;
			len -= r;
			r = ptr - buf;
			continue;
		}
		if (errno == EINTR) {
			/* ignore */
			r = 1;
			continue;
		}
		if (!(errno == EWOULDBLOCK || errno == EAGAIN)) {
			/* real error */
			break;
		}
		r = 1;
	}
	SET_RETURN_OUT(r, out, r)
	return (r); 
}

/*
 * Threaded recvfrom 
 */
int 
jthreadedRecvfrom(int fd, void* buf, size_t len, int flags, 
	struct sockaddr* from, int* fromlen, int timeout, ssize_t *out)
{
	int r;
	jlong deadline = 0;
 
	SET_DEADLINE(deadline, timeout)
	for (;;) {
		r = recvfrom(fd, buf, len, flags, from, fromlen);
		if (r >= 0 || !(errno == EWOULDBLOCK || errno == EINTR 
					|| errno == EAGAIN)) {
			break;
		}
		IGNORE_EINTR(r)
		BREAK_IF_LATE(deadline, timeout)
	}
	SET_RETURN_OUT(r, out, r)
	return (r);
}

/* helper function for forkexec, close fd[0..n-1] */
static void
close_fds(int fd[], int n)
{
        int i = 0;
        while (i < n) {
                close(fd[i++]);
	}
}

int 
jthreadedForkExec(char **argv, char **arge,
	int ioes[4], int *outpid, const char *dir)
{
/* these defines are indices in ioes */
#define IN_IN		0
#define IN_OUT		1
#define OUT_IN		2
#define OUT_OUT		3
#define ERR_IN		4
#define ERR_OUT		5
#define SYNC_IN		6
#define SYNC_OUT	7

	int fds[8];
	int nfd;		/* number of fds in `fds' that are valid */
	sigset_t nsig;
	char b[1];
	int pid, i, err;

	/* 
	 * we need execve() and fork() for this to work.  Don't bother if
	 * we don't have them.
	 */
#if !defined(HAVE_EXECVE) && !defined(HAVE_EXECVP)
	unimp("neither execve() nor execvp() provided");
#endif
#if !defined(HAVE_FORK)
	unimp("fork() not provided");
#endif

	/* Create the pipes to communicate with the child */
	/* Make sure fds get closed if we can't create all pipes */
	for (nfd = 0; nfd < 8; nfd += 2) {
		int e;
		err = pipe(fds + nfd);
		e = errno;
		if (err == -1) {
			close_fds(fds, nfd);
			return (e);
		}
	}

	/* 
	 * We must avoid that the child dies because of SIGVTALRM or
	 * other signals.  We disable interrupts before forking and then
	 * reenable signals in the child after we cleaned up.
	 */
	sigfillset(&nsig);
	sigprocmask(SIG_BLOCK, &nsig, 0);

	pid = fork();

	switch (pid) {
	case 0:
		/* Child */
		/* set all signals back to their default state */
		for (i = 0; i < NSIG; i++) {
			clearSignal(i);
		}

		/* now reenable interrupts */
		sigprocmask(SIG_UNBLOCK, &nsig, 0);

		/* set stdin, stdout, and stderr up from the pipes */
		dup2(fds[IN_IN], 0);
		dup2(fds[OUT_OUT], 1);
		dup2(fds[ERR_OUT], 2);

		/* What is sync about anyhow?  Well my current guess is that
		 * the parent writes a single byte to it when it's ready to
		 * proceed.  So here I wait until I get it before doing
		 * anything.
		 */
		/* note that this is a blocking read */
		read(fds[SYNC_IN], b, sizeof(b));

		/* now close all pipe fds */
		close_fds(fds, 8);

		/* change working directory */
#if defined(HAVE_CHDIR)
		(void)chdir(dir);
#endif

		/*
		 * If no environment was given and we have execvp, we use it.
		 * If an environment was given, we use execve.
		 * This is roughly was the linux jdk seems to do.
		 */

		/* execute program */
#if defined(HAVE_EXECVP)
		if (arge == NULL)
			execvp(argv[0], argv);
		else
#endif
			execve(argv[0], argv, arge);
		break;

	case -1:
		/* Error */
		err = errno;
		/* Close all pipe fds */
		close_fds(fds, 8);
		sigprocmask(SIG_UNBLOCK, &nsig, 0);
		return (err);

	default:
		/* Parent */
		/* close the fds we won't need */
		close(fds[IN_IN]);
		close(fds[OUT_OUT]);
		close(fds[ERR_OUT]);
		close(fds[SYNC_IN]);

		/* copy and fix up the fds we do need */
		ioes[0] = fds[IN_OUT];
		ioes[1] = fds[OUT_IN];
		ioes[2] = fds[ERR_IN];
		ioes[3] = fds[SYNC_OUT];

		sigprocmask(SIG_UNBLOCK, &nsig, 0);
		*outpid = pid;
		return (0);
	}

	exit(-1);
	/* NEVER REACHED */	
}

/* 
 * Wait for a child process.
 */
int
jthreadedWaitpid(int wpid, int* status, int options, int *outpid)
{
#if defined(HAVE_WAITPID)
	int npid;

	npid = waitpid(wpid, status, options);
	if (npid > 0) {
		*outpid = npid;
		return (0);
	}
	else {
		return (-1);
	}
#else
	return (-1);
#endif
}

int
jthreadedMmap(void **memory, size_t *size, int mode, int fd, off_t *offset)
{
#if defined(HAVE_MMAP)
	size_t pages_sz;
	off_t pages_offset;
	int sysmode, sysflags;
	int rc = 0;

	pages_sz = (*size)/getpagesize();
	*size = (pages_sz+1)*getpagesize();
  
	pages_offset = (*offset)/getpagesize();
	*offset = pages_offset*getpagesize();

	switch (mode) {
		case KAFFE_MMAP_READ:
			sysflags = MAP_SHARED;
			sysmode = PROT_READ;
			break;
		case KAFFE_MMAP_WRITE:
			sysflags = MAP_SHARED;
			sysmode = PROT_WRITE | PROT_READ;
			break;
		case KAFFE_MMAP_PRIVATE:
			sysflags = MAP_PRIVATE;
			sysmode = PROT_WRITE | PROT_READ;
			break;
		default:
			return -EINVAL;
	}

	*memory = mmap(*memory, *size, sysmode, sysflags, fd, *offset);

	return (rc);
#else
	return (ENOTSUP);
#endif
}


static int
jthreadedMunmap(void *memory, size_t size)
{
#if defined(HAVE_MMAP)
	int rc = 0;
	
	if (munmap(memory, size) < 0) {
		rc = errno;
	}
	return (rc);
#else
	return (ENOTSUP);
#endif
}

static int
jthreadedMsync(void *memory, size_t size)
{
#if defined(HAVE_MMAP)
        int rc = 0;

        memory = (void *)(((size_t)memory/getpagesize()) * getpagesize());
        size += getpagesize();
        /* TODO: Try not to freeze the entire VM. */
        if (msync(memory, size, MS_SYNC | MS_INVALIDATE) < 0) {
            rc = errno;
        }

        return rc;
#else
        return (ENOTSUP);
#endif
}

int jthreadedPipeCreate(int *read_fd, int *write_fd)
{
	int pairs[2];

	assert(read_fd != NULL);
	assert(write_fd != NULL);

	if (pipe(pairs) < 0)
		return errno;

	*read_fd = pairs[0];
	*write_fd = pairs[1];

	return 0;
}

/*
 * The syscall interface as provided by the internal jthread system.
 */
SystemCallInterface Kaffe_SystemCallInterface = {
        jthreadedOpen,
        jthreadedRead,	
        jthreadedWrite, 
        jthreadedLSeek,
        jthreadedClose,
        jthreadedFStat,
        jthreadedStat,
        jthreadedFTruncate,
        jthreadedFSync,
        jthreadedMkdir,
        jthreadedRmdir,
        jthreadedRename,
        jthreadedRemove,
        jthreadedSocket,
        jthreadedConnect,
        jthreadedBind,
        jthreadedListen,
        jthreadedAccept, 
        jthreadedTimedRead,	
        jthreadedRecvfrom,
        jthreadedWrite, 
        jthreadedSendto,	
        jthreadedSetSockOpt,	
        jthreadedGetSockOpt,
        jthreadedGetSockName, 
        jthreadedGetPeerName, 
        jthreadedClose,
        jthreadedGetHostByName,
        jthreadedGetHostByAddr,
        jthreadedSelect,	
        jthreadedForkExec,
        jthreadedWaitpid,
        jthreadedKill,
        jthreadedMmap,
        jthreadedMunmap,
	jthreadedMsync,
	jthreadedPipeCreate,
	jthreadedTimedRead,
	jthreadedTimedWrite
};