#include "sm/generic.h"
SM_RCSID("@(#)$Id: recvfd.c,v 1.5 2005/06/16 20:39:02 ca Exp $")
#include "sm/assert.h"
#include "sm/error.h"
#include "sm/io.h"
#include "sm/varargs.h"
#include "sm/limits.h"
#include "sm/types.h"

/* Receive a file descriptor from another process (a server).
 * In addition, any data received from the server is passed
 * to (*userfunc)(STDERR_FILENO, buf, nbytes).  We have a
 * 2-byte protocol for receiving the fd from send_fd().
 */

#define MAXLINE	16

#if LIB44_FD
#include <sys/types.h>
#include <sys/socket.h>		/* struct msghdr */
#include <sys/uio.h>		/* struct iovec */
#include <stddef.h>

static struct cmsghdr	*cmptr = NULL;		/* malloc'ed first time */
#define CONTROLLEN	(sizeof(struct cmsghdr) + sizeof(int))
		 /* size of control buffer to send/recv one file descriptor */

sm_ret_T
recv_fd(int servfd)
{
	int		newfd, nread, status;
	char		*ptr, buf[MAXLINE];
	struct iovec	iov[1];
	struct msghdr	msg;

	status = -1;
	for ( ; ; )
	{
		iov[0].iov_base = buf;
		iov[0].iov_len  = sizeof(buf);
		msg.msg_iov     = iov;
		msg.msg_iovlen  = 1;
		msg.msg_name    = NULL;
		msg.msg_namelen = 0;
		if (cmptr == NULL && (cmptr = malloc(CONTROLLEN)) == NULL)
			return sm_error_temp(SM_EM_IO, ENOMEM);
		msg.msg_control    = (caddr_t) cmptr;
		msg.msg_controllen = CONTROLLEN;

		if ((nread = recvmsg(servfd, &msg, 0)) < 0)
			return sm_error_perm(SM_EM_IO, errno);
		else if (nread == 0)
		{
			return SM_IO_EOF;
		}
		/*
		   See if this is the final data with null & status.
		   Null must be next to last byte of buffer, status
		   byte is last byte.  Zero status means there must
		   be a file descriptor to receive.
		*/
		for (ptr = buf; ptr < &buf[nread]; )
		{
			if (*ptr++ == 0)
			{
				if (ptr != &buf[nread-1])
					return sm_error_perm(SM_EM_IO, EINVAL);
				status = *ptr & 255;
				if (status == 0)
				{
					if (msg.msg_controllen != CONTROLLEN)
						return sm_error_perm(SM_EM_IO, EINVAL);
					/*
					err_dump("status = 0 but no fd");
					*/

					newfd = *(int *)CMSG_DATA(cmptr); /* new descriptor */
				}
				else
					newfd = -status;
				nread -= 2;
			}
		}
#if 0
		if (nread > 0)
			if ((*userfunc)(STDERR_FILENO, buf, nread) != nread)
				return(-1);
#endif /* 0 */
		if (status >= 0)	/* final data has arrived */
			return(newfd);	/* descriptor, or -status */
	}
}
#endif /* LIB44_FD */

#if LIBSUN_FD
#include <sys/types.h>
#include <sys/socket.h>		/* struct msghdr */
#include <sys/uio.h>			/* struct iovec */
#include <stddef.h>

/* Receive a file descriptor from another process (a server).
 * In addition, any data received from the server is passed
 * to (*userfunc)(STDERR_FILENO, buf, nbytes).  We have a
 * 2-byte protocol for receiving the fd from send_fd().
 */

sm_ret_T
recv_fd(int servfd)
{
	int		newfd, nread, status;
	char		*ptr, buf[MAXLINE];
	struct iovec	iov[1];
	struct msghdr	msg;
	status = -1;
	for ( ; ; )
	{
		iov[0].iov_base = buf;
		iov[0].iov_len  = sizeof(buf);
		msg.msg_iov     = iov;
		msg.msg_iovlen  = 1;
		msg.msg_name    = NULL;
		msg.msg_namelen = 0;
		msg.msg_accrights = (caddr_t) &newfd;/* addr of descriptor */
		msg.msg_accrightslen = sizeof(int);	 /* receive 1 descriptor */

		if ( (nread = recvmsg(servfd, &msg, 0)) < 0)
			return sm_error_perm(SM_EM_IO, errno);
		else if (nread == 0)
		{
			return SM_IO_EOF;
		}

		/*
		   See if this is the final data with null & status.
		   Null must be next to last byte of buffer, status
		   byte is last byte.  Zero status means there must
		   be a file descriptor to receive.
		*/
		for (ptr = buf; ptr < &buf[nread]; )
		{
			if (*ptr++ == 0)
			{
				if (ptr != &buf[nread-1])
					return sm_error_perm(SM_EM_IO, EINVAL);
				status = *ptr & 255;
				if (status == 0)
				{
					if (msg.msg_accrightslen != sizeof(int))
						return sm_error_perm(SM_EM_IO, EINVAL);
					/* newfd = the new descriptor */
				}
				else
					newfd = -status;
				nread -= 2;
			}
		}
/*
		if (nread > 0)
			if ((*userfunc)(STDERR_FILENO, buf, nread) != nread)
				return(-1);
*/

		if (status >= 0)	/* final data has arrived */
			return(newfd);	/* descriptor, or -status */
	}
}
#endif /* LIBSUN_FD */

#if LIBSYSV_FD
#include <sys/types.h>
#include <stropts.h>

sm_ret_T
recv_fd(int servfd, ssize_t (*userfunc)(int, const void *, size_t))
{
	int			newfd, nread, flag, status;
	char			*ptr, buf[MAXLINE];
	struct strbuf		dat;
	struct strrecvfd	recvfd;

	status = -1;
	for ( ; ; )
	{
		dat.buf = buf;
		dat.maxlen = MAXLINE;
		flag = 0;
		if (getmsg(servfd, NULL, &dat, &flag) < 0)
			return sm_error_temp(SM_EM_IO, ENOMEM);
		nread = dat.len;
		if (nread == 0)
		{
			return SM_IO_EOF;
		}
		/*
		   See if this is the final data with null & status.
		   Null must be next to last byte of buffer, status
		   byte is last byte.  Zero status means there must
		   be a file descriptor to receive.
		*/
		for (ptr = buf; ptr < &buf[nread]; )
		{
			if (*ptr++ == 0)
			{
				if (ptr != &buf[nread-1])
					return sm_error_perm(SM_EM_IO, errno);
				status = *ptr & 255;
				if (status == 0)
				{
					if (ioctl(servfd, I_RECVFD, &recvfd) < 0)
						return SM_IO_EOF;
					newfd = recvfd.fd;	/* new descriptor */
				} else
					newfd = -status;
				nread -= 2;
			}
		}
/*
		if (nread > 0)
			if ((*userfunc)(STDERR_FILENO, buf, nread) != nread)
				return(-1);
*/

		if (status >= 0)	/* final data has arrived */
			return(newfd);	/* descriptor, or -status */
	}
}
#endif /* LIBSYSV_FD */