Add original unix v6

sys/ken/fio.c

@@ -0,0 +1,258 @@
+#
+/*
+ */
+
+#include "../param.h"
+#include "../user.h"
+#include "../filsys.h"
+#include "../file.h"
+#include "../conf.h"
+#include "../inode.h"
+#include "../reg.h"
+
+/*
+ * Convert a user supplied
+ * file descriptor into a pointer
+ * to a file structure.
+ * Only task is to check range
+ * of the descriptor.
+ */
+getf(f)
+{
+	register *fp, rf;
+
+	rf = f;
+	if(rf<0 || rf>=NOFILE)
+		goto bad;
+	fp = u.u_ofile[rf];
+	if(fp != NULL)
+		return(fp);
+bad:
+	u.u_error = EBADF;
+	return(NULL);
+}
+
+/*
+ * Internal form of close.
+ * Decrement reference count on
+ * file structure and call closei
+ * on last closef.
+ * Also make sure the pipe protocol
+ * does not constipate.
+ */
+closef(fp)
+int *fp;
+{
+	register *rfp, *ip;
+
+	rfp = fp;
+	if(rfp->f_flag&FPIPE) {
+		ip = rfp->f_inode;
+		ip->i_mode =& ~(IREAD|IWRITE);
+		wakeup(ip+1);
+		wakeup(ip+2);
+	}
+	if(rfp->f_count <= 1)
+		closei(rfp->f_inode, rfp->f_flag&FWRITE);
+	rfp->f_count--;
+}
+
+/*
+ * Decrement reference count on an
+ * inode due to the removal of a
+ * referencing file structure.
+ * On the last closei, switchout
+ * to the close entry point of special
+ * device handler.
+ * Note that the handler gets called
+ * on every open and only on the last
+ * close.
+ */
+closei(ip, rw)
+int *ip;
+{
+	register *rip;
+	register dev, maj;
+
+	rip = ip;
+	dev = rip->i_addr[0];
+	maj = rip->i_addr[0].d_major;
+	if(rip->i_count <= 1)
+	switch(rip->i_mode&IFMT) {
+
+	case IFCHR:
+		(*cdevsw[maj].d_close)(dev, rw);
+		break;
+
+	case IFBLK:
+		(*bdevsw[maj].d_close)(dev, rw);
+	}
+	iput(rip);
+}
+
+/*
+ * openi called to allow handler
+ * of special files to initialize and
+ * validate before actual IO.
+ * Called on all sorts of opens
+ * and also on mount.
+ */
+openi(ip, rw)
+int *ip;
+{
+	register *rip;
+	register dev, maj;
+
+	rip = ip;
+	dev = rip->i_addr[0];
+	maj = rip->i_addr[0].d_major;
+	switch(rip->i_mode&IFMT) {
+
+	case IFCHR:
+		if(maj >= nchrdev)
+			goto bad;
+		(*cdevsw[maj].d_open)(dev, rw);
+		break;
+
+	case IFBLK:
+		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 except for EXEC where
+ * at least one of the EXEC bits must
+ * be on.
+ */
+access(aip, mode)
+int *aip;
+{
+	register *ip, m;
+
+	ip = aip;
+	m = mode;
+	if(m == IWRITE) {
+		if(getfs(ip->i_dev)->s_ronly != 0) {
+			u.u_error = EROFS;
+			return(1);
+		}
+		if(ip->i_flag & ITEXT) {
+			u.u_error = ETXTBSY;
+			return(1);
+		}
+	}
+	if(u.u_uid == 0) {
+		if(m == IEXEC && (ip->i_mode & 
+			(IEXEC | (IEXEC>>3) | (IEXEC>>6))) == 0)
+				goto bad;
+		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);
+
+bad:
+	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.
+ */
+owner()
+{
+	register struct inode *ip;
+	extern uchar();
+
+	if ((ip = namei(uchar, 0)) == 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)
+		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_ar0[R0] = i;
+			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.
+ */
+falloc()
+{
+	register struct file *fp;
+	register i;
+
+	if ((i = ufalloc()) < 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_offset[0] = 0;
+			fp->f_offset[1] = 0;
+			return(fp);
+		}
+	printf("no file\n");
+	u.u_error = ENFILE;
+	return(NULL);
+}