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    Length: 3091 (0xc13)
    Types: TextFile
    Notes: UNIX file
    Names: »fd.c«

└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
    └─⟦2d53db1df⟧ UNIX V7 Filesystem
        └─ ⟦this⟧ »sys/coh/fd.c« 

TextFile

/* (-lgl
 * 	The information contained herein is a trade secret of Mark Williams
 * 	Company, and  is confidential information.  It is provided  under a
 * 	license agreement,  and may be  copied or disclosed  only under the
 * 	terms of  that agreement.  Any  reproduction or disclosure  of this
 * 	material without the express written authorization of Mark Williams
 * 	Company or persuant to the license agreement is unlawful.
 * 
 * 	COHERENT Version 0.7.3
 * 	Copyright (c) 1982, 1983, 1984.
 * 	An unpublished work by Mark Williams Company, Chicago.
 * 	All rights reserved.
 -lgl) */
/*
 * Coherent.
 * File descriptor routines.
 */
#include <coherent.h>
#include <errno.h>
#include <fd.h>
#include <inode.h>
#include <uproc.h>

/*
 * Given a file number, return the file descriptor.
 */
FD *
fdget(fd)
register unsigned fd;
{
	register FD *fdp;

	if (fd>=NUFILE || (fdp=u.u_filep[fd])==NULL) {
		u.u_error = EBADF;
		return (NULL);
	}
	return (fdp);
}

/*
 * Duplicate a file descriptor number.  This has the same calling
 * sequence as the dup2 system call and even uses the silly DUP2 bit.
 */
fddup(ofd, nfd)
register unsigned ofd;
register unsigned nfd;
{
	register FD *fdp;

	if ((fdp=fdget(ofd&~DUP2)) == NULL)
		return (-1);
	if ((ofd&DUP2) != 0) {
		if (nfd >= NUFILE) {
			u.u_error = EBADF;
			return (-1);
		}
		ofd &= ~DUP2;
		if (ofd == nfd)
			return (nfd);
		if (u.u_filep[nfd] != NULL) {
			fdclose(nfd);
			if (u.u_error)
				return (-1);
		}
	} else {
		for (nfd=0; nfd<NUFILE; nfd++)
			if (u.u_filep[nfd] == NULL)
				break;
		if (nfd == NUFILE) {
			u.u_error = EMFILE;
			return (-1);
		}
	}
	u.u_filep[nfd] = fdp;
	fdp->f_refc++;
	return (nfd);
}

/*
 * Given an inode, and a mode containing permission flags, open the
 * inode with the appropriate permissions and return a file descriptor
 * containing it.
 */
fdopen(ip, mode)
register INODE *ip;
{
	register FD **fdpp;
	register FD *fdp;

	for (fdpp=u.u_filep; fdpp<&u.u_filep[NUFILE]; fdpp++) {
		if (*fdpp != NULL)
			continue;
		if ((fdp=kalloc(sizeof(FD))) == NULL)
			return (-1);
		iopen(ip, mode);
		if (u.u_error) {
			kfree(fdp);
			return (-1);
		}
		fdp->f_flag = mode;
		fdp->f_refc = 1;
		fdp->f_seek = 0;
		fdp->f_ip = ip;
		*fdpp = fdp;
		return (fdpp-u.u_filep);
	}
	u.u_error = EMFILE;
	return (-1);
}

/*
 * Close the given file number.
 */
fdclose(fd)
register unsigned fd;
{
	register FD *fdp;

	if (fd>=NUFILE || (fdp=u.u_filep[fd])==NULL) {
		u.u_error = EBADF;
		return;
	}
	u.u_filep[fd] = NULL;
	if (fdp->f_refc == 0)
		panic("fdclose()");
	if (--fdp->f_refc == 0) {
		iclose(fdp->f_ip);
		kfree(fdp);
	}
}

/*
 * Assuming we have made a copy of the user area, increment the reference
 * of all open files.  (used in fork).
 */
fdadupl()
{
	register FD **fdpp;
	register FD *fdp;

	for (fdpp=u.u_filep; fdpp<&u.u_filep[NUFILE]; fdpp++) {
		if ((fdp=*fdpp) == NULL)
			continue;
		fdp->f_refc++;
	}
}

/*
 * Close all open files in the current process.
 */
fdaclose()
{
	register int fd;

	for (fd=0; fd<NUFILE; fd++) {
		if (u.u_filep[fd] == NULL)
			continue;
		fdclose(fd);
	}
}