remove holdfp()

Replace uses of holdfp() with fget*() or fgetvp*() calls as appropriate

introduce fget(), fget_read(), fget_write() - these functions will take
a thread and file descriptor and return a file pointer with its ref
count bumped.

introduce fgetvp(), fgetvp_read(), fgetvp_write() - these functions will
take a thread and file descriptor and return a vref()'d vnode.

*_read() requires that the file pointer be FREAD, *_write that it be
FWRITE.

This continues the cleanup of struct filedesc and struct file access
routines which, when are all through with it, will allow us to then
make the API calls MP safe and be able to move Giant down into the fo_*
functions.

1 files changed, 32 insertions, 56 deletions

diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 17cee14..352e325 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -83,22 +83,6 @@ static int	dofileread __P((struct thread *, struct file *, int, void *,
 static int	dofilewrite __P((struct thread *, struct file *, int,
 		    const void *, size_t, off_t, int));
 
-struct file*
-holdfp(fdp, fd, flag)
-	struct filedesc* fdp;
-	int fd, flag;
-{
-	struct file* fp;
-
-	if (((u_int)fd) >= fdp->fd_nfiles ||
-	    (fp = fdp->fd_ofiles[fd]) == NULL ||
-	    (fp->f_flag & flag) == 0) {
-		return (NULL);
-	}
-	fhold(fp);
-	return (fp);
-}
-
 /*
  * Read system call.
  */
@@ -115,18 +99,16 @@ struct read_args {
 int
 read(td, uap)
 	struct thread *td;
-	register struct read_args *uap;
+	struct read_args *uap;
 {
-	register struct file *fp;
+	struct file *fp;
 	int error;
 
 	mtx_lock(&Giant);
-	if ((fp = holdfp(td->td_proc->p_fd, uap->fd, FREAD)) != NULL) {
+	if ((error = fget_read(td, uap->fd, &fp)) == 0) {
 		error = dofileread(td, fp, uap->fd, uap->buf,
 			    uap->nbyte, (off_t)-1, 0);
 		fdrop(fp, td);
-	} else {
-		error = EBADF;
 	}
 	mtx_unlock(&Giant);
 	return(error);
@@ -150,20 +132,19 @@ struct pread_args {
 int
 pread(td, uap)
 	struct thread *td;
-	register struct pread_args *uap;
+	struct pread_args *uap;
 {
-	register struct file *fp;
+	struct file *fp;
 	int error;
 
 	mtx_lock(&Giant);
-	if ((fp = holdfp(td->td_proc->p_fd, uap->fd, FREAD)) == NULL) {
-		error = EBADF;
-	} else if (fp->f_type != DTYPE_VNODE) {
-		error = ESPIPE;
-		fdrop(fp, td);
-	} else {
-		error = dofileread(td, fp, uap->fd, uap->buf, uap->nbyte, 
-			    uap->offset, FOF_OFFSET);
+	if ((error = fget_read(td, uap->fd, &fp)) == 0) {
+		if (fp->f_type == DTYPE_VNODE) {
+			error = dofileread(td, fp, uap->fd, uap->buf, 
+				    uap->nbyte, uap->offset, FOF_OFFSET);
+		} else {
+			error = ESPIPE;
+		}
 		fdrop(fp, td);
 	}
 	mtx_unlock(&Giant);
@@ -247,12 +228,11 @@ struct readv_args {
 int
 readv(td, uap)
 	struct thread *td;
-	register struct readv_args *uap;
+	struct readv_args *uap;
 {
-	register struct file *fp;
-	register struct filedesc *fdp;
+	struct file *fp;
 	struct uio auio;
-	register struct iovec *iov;
+	struct iovec *iov;
 	struct iovec *needfree;
 	struct iovec aiov[UIO_SMALLIOV];
 	long i, cnt, error = 0;
@@ -262,12 +242,9 @@ readv(td, uap)
 	struct uio ktruio;
 #endif
 	mtx_lock(&Giant);
-	fdp = td->td_proc->p_fd;
 
-	if ((fp = holdfp(fdp, uap->fd, FREAD)) == NULL) {
-		error = EBADF;
+	if ((error = fget_read(td, uap->fd, &fp)) != 0)
 		goto done2;
-	}
 	/* note: can't use iovlen until iovcnt is validated */
 	iovlen = uap->iovcnt * sizeof (struct iovec);
 	if (uap->iovcnt > UIO_SMALLIOV) {
@@ -352,18 +329,18 @@ struct write_args {
 int
 write(td, uap)
 	struct thread *td;
-	register struct write_args *uap;
+	struct write_args *uap;
 {
-	register struct file *fp;
+	struct file *fp;
 	int error;
 
 	mtx_lock(&Giant);
-	if ((fp = holdfp(td->td_proc->p_fd, uap->fd, FWRITE)) != NULL) {
+	if ((error = fget_write(td, uap->fd, &fp)) == 0) {
 		error = dofilewrite(td, fp, uap->fd, uap->buf, uap->nbyte,
 			    (off_t)-1, 0);
 		fdrop(fp, td);
 	} else {
-		error = EBADF;
+		error = EBADF;	/* XXX this can't be right */
 	}
 	mtx_unlock(&Giant);
 	return(error);
@@ -387,21 +364,22 @@ struct pwrite_args {
 int
 pwrite(td, uap)
 	struct thread *td;
-	register struct pwrite_args *uap;
+	struct pwrite_args *uap;
 {
-	register struct file *fp;
+	struct file *fp;
 	int error;
 
 	mtx_lock(&Giant);
-	if ((fp = holdfp(td->td_proc->p_fd, uap->fd, FWRITE)) == NULL) {
-		error = EBADF;
-	} else if (fp->f_type != DTYPE_VNODE) {
-		error = ESPIPE;
+	if ((error = fget_write(td, uap->fd, &fp)) == 0) {
+		if (fp->f_type == DTYPE_VNODE) {
+			error = dofilewrite(td, fp, uap->fd, uap->buf,
+				    uap->nbyte, uap->offset, FOF_OFFSET);
+		} else {
+			error = ESPIPE;
+		}
 		fdrop(fp, td);
 	} else {
-		error = dofilewrite(td, fp, uap->fd, uap->buf, uap->nbyte,
-			    uap->offset, FOF_OFFSET);
-		fdrop(fp, td);
+		error = EBADF;	/* this can't be right */
 	}
 	mtx_unlock(&Giant);
 	return(error);
@@ -489,8 +467,7 @@ writev(td, uap)
 	struct thread *td;
 	register struct writev_args *uap;
 {
-	register struct file *fp;
-	register struct filedesc *fdp;
+	struct file *fp;
 	struct uio auio;
 	register struct iovec *iov;
 	struct iovec *needfree;
@@ -503,8 +480,7 @@ writev(td, uap)
 #endif
 
 	mtx_lock(&Giant);
-	fdp = td->td_proc->p_fd;
-	if ((fp = holdfp(fdp, uap->fd, FWRITE)) == NULL) {
+	if ((error = fget_write(td, uap->fd, &fp)) != 0) {
 		error = EBADF;
 		goto done2;
 	}