From 08bbdb8b8b07791c8fcea5dce32f9895a6a64065 Mon Sep 17 00:00:00 2001
From: Ken Thompson <ken@research.uucp>
Date: Mon, 7 May 1979 01:25:41 -0500
Subject: [PATCH] Research V7 development Work on file usr/sys/sys/fio.c

Synthesized-from: v7
---
 usr/sys/sys/fio.c | 260 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 260 insertions(+)
 create mode 100644 usr/sys/sys/fio.c

diff --git a/usr/sys/sys/fio.c b/usr/sys/sys/fio.c
new file mode 100644
index 0000000000..57286f339b
--- /dev/null
+++ b/usr/sys/sys/fio.c
@@ -0,0 +1,260 @@
+#include "../h/param.h"
+#include "../h/systm.h"
+#include "../h/dir.h"
+#include "../h/user.h"
+#include "../h/filsys.h"
+#include "../h/file.h"
+#include "../h/conf.h"
+#include "../h/inode.h"
+#include "../h/reg.h"
+#include "../h/acct.h"
+
+/*
+ * Convert a user supplied
+ * file descriptor into a pointer
+ * to a file structure.
+ * Only task is to check range
+ * of the descriptor.
+ */
+struct file *
+getf(f)
+register int f;
+{
+	register struct file *fp;
+
+	if(0 <= f && f < NOFILE) {
+		fp = u.u_ofile[f];
+		if(fp != NULL)
+			return(fp);
+	}
+	u.u_error = EBADF;
+	return(NULL);
+}
+
+/*
+ * Internal form of close.
+ * Decrement reference count on
+ * file structure.
+ * Also make sure the pipe protocol
+ * does not constipate.
+ *
+ * Decrement reference count on the inode following
+ * removal to the referencing file structure.
+ * Call device handler on last close.
+ */
+closef(fp)
+register struct file *fp;
+{
+	register struct inode *ip;
+	int flag, mode;
+	dev_t dev;
+	register int (*cfunc)();
+	struct chan *cp;
+
+	if(fp == NULL)
+		return;
+	if (fp->f_count > 1) {
+		fp->f_count--;
+		return;
+	}
+	ip = fp->f_inode;
+	flag = fp->f_flag;
+	cp = fp->f_un.f_chan;
+	dev = (dev_t)ip->i_un.i_rdev;
+	mode = ip->i_mode;
+
+	plock(ip);
+	fp->f_count = 0;
+	if(flag & FPIPE) {
+		ip->i_mode &= ~(IREAD|IWRITE);
+		wakeup((caddr_t)ip+1);
+		wakeup((caddr_t)ip+2);
+	}
+	iput(ip);
+
+	switch(mode&IFMT) {
+
+	case IFCHR:
+	case IFMPC:
+		cfunc = cdevsw[major(dev)].d_close;
+		break;
+
+	case IFBLK:
+	case IFMPB:
+		cfunc = bdevsw[major(dev)].d_close;
+		break;
+	default:
+		return;
+	}
+
+	if ((flag & FMP) == 0)
+		for(fp=file; fp < &file[NFILE]; fp++)
+			if (fp->f_count && fp->f_inode==ip)
+				return;
+	(*cfunc)(dev, flag, cp);
+}
+
+/*
+ * openi called to allow handler
+ * of special files to initialize and
+ * validate before actual IO.
+ */
+openi(ip, rw)
+register struct inode *ip;
+{
+	dev_t dev;
+	register unsigned int maj;
+
+	dev = (dev_t)ip->i_un.i_rdev;
+	maj = major(dev);
+	switch(ip->i_mode&IFMT) {
+
+	case IFCHR:
+	case IFMPC:
+		if(maj >= nchrdev)
+			goto bad;
+		(*cdevsw[maj].d_open)(dev, rw);
+		break;
+
+	case IFBLK:
+	case IFMPB:
+		if(maj >= nblkdev)
+			goto bad;
+		(*bdevsw[maj].d_open)(dev, rw);
+	}
+	return;
+
+bad:
+	u.u_error = ENXIO;
+}
+
+/*
+ * Check mode permission on inode pointer.
+ * Mode is READ, WRITE or EXEC.
+ * In the case of WRITE, the
+ * read-only status of the file
+ * system is checked.
+ * Also in WRITE, prototype text
+ * segments cannot be written.
+ * The mode is shifted to select
+ * the owner/group/other fields.
+ * The super user is granted all
+ * permissions.
+ */
+access(ip, mode)
+register struct inode *ip;
+{
+	register m;
+
+	m = mode;
+	if(m == IWRITE) {
+		if(getfs(ip->i_dev)->s_ronly != 0) {
+			u.u_error = EROFS;
+			return(1);
+		}
+		if (ip->i_flag&ITEXT)		/* try to free text */
+			xrele(ip);
+		if(ip->i_flag & ITEXT) {
+			u.u_error = ETXTBSY;
+			return(1);
+		}
+	}
+	if(u.u_uid == 0)
+		return(0);
+	if(u.u_uid != ip->i_uid) {
+		m >>= 3;
+		if(u.u_gid != ip->i_gid)
+			m >>= 3;
+	}
+	if((ip->i_mode&m) != 0)
+		return(0);
+
+	u.u_error = EACCES;
+	return(1);
+}
+
+/*
+ * Look up a pathname and test if
+ * the resultant inode is owned by the
+ * current user.
+ * If not, try for super-user.
+ * If permission is granted,
+ * return inode pointer.
+ */
+struct inode *
+owner()
+{
+	register struct inode *ip;
+
+	ip = namei(uchar, 0);
+	if(ip == NULL)
+		return(NULL);
+	if(u.u_uid == ip->i_uid)
+		return(ip);
+	if(suser())
+		return(ip);
+	iput(ip);
+	return(NULL);
+}
+
+/*
+ * Test if the current user is the
+ * super user.
+ */
+suser()
+{
+
+	if(u.u_uid == 0) {
+		u.u_acflag |= ASU;
+		return(1);
+	}
+	u.u_error = EPERM;
+	return(0);
+}
+
+/*
+ * Allocate a user file descriptor.
+ */
+ufalloc()
+{
+	register i;
+
+	for(i=0; i<NOFILE; i++)
+		if(u.u_ofile[i] == NULL) {
+			u.u_r.r_val1 = i;
+			u.u_pofile[i] = 0;
+			return(i);
+		}
+	u.u_error = EMFILE;
+	return(-1);
+}
+
+/*
+ * Allocate a user file descriptor
+ * and a file structure.
+ * Initialize the descriptor
+ * to point at the file structure.
+ *
+ * no file -- if there are no available
+ * 	file structures.
+ */
+struct file *
+falloc()
+{
+	register struct file *fp;
+	register i;
+
+	i = ufalloc();
+	if(i < 0)
+		return(NULL);
+	for(fp = &file[0]; fp < &file[NFILE]; fp++)
+		if(fp->f_count == 0) {
+			u.u_ofile[i] = fp;
+			fp->f_count++;
+			fp->f_un.f_offset = 0;
+			return(fp);
+		}
+	printf("no file\n");
+	u.u_error = ENFILE;
+	return(NULL);
+}
-- 
2.20.1