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Allow seeks on raw devices. A `f_offset' field is added to the file structure 

which is maintained in lseek(), read() and write(), and passed along to
the device's strategy routine.
This commit is contained in:
pk 1996-06-21 20:09:03 +00:00
parent 3a375fb249
commit b461ef1d17
4 changed files with 27 additions and 9 deletions
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21
sys/lib/libsa/lseek.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: lseek.c,v 1.2 1994/10/26 05:44:51 cgd Exp $ */
/* $NetBSD: lseek.c,v 1.3 1996/06/21 20:09:03 pk Exp $ */
/*-
* Copyright (c) 1993
@ -79,10 +79,23 @@ lseek(fd, offset, where)
return (-1);
}
/* seek is not supported on raw devices */
if (f->f_flags & F_RAW) {
errno = EOFFSET;
return ((off_t)-1);
/*
* On RAW devices, update internal offset.
*/
switch (where) {
case SEEK_SET:
f->f_offset = offset;
break;
case SEEK_CUR:
f->f_offset += offset;
break;
case SEEK_END:
default:
errno = EOFFSET;
return (-1);
}
return (f->f_offset);
}
return (f->f_ops->seek)(f, offset, where);

6
sys/lib/libsa/read.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: read.c,v 1.5 1995/09/14 23:45:35 pk Exp $ */
/* $NetBSD: read.c,v 1.6 1996/06/21 20:09:04 pk Exp $ */
/*-
* Copyright (c) 1993
@ -64,6 +64,7 @@
* rights to redistribute these changes.
*/
#include <sys/param.h>
#include "stand.h"
ssize_t
@ -82,9 +83,10 @@ read(fd, dest, bcount)
if (f->f_flags & F_RAW) {
twiddle();
errno = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
(daddr_t)0, bcount, dest, &resid);
btodb(f->f_offset), bcount, dest, &resid);
if (errno)
return (-1);
f->f_offset += (bcount - resid);
return (resid);
}
resid = bcount;

3
sys/lib/libsa/stand.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: stand.h,v 1.13 1996/01/13 22:25:42 leo Exp $ */
/* $NetBSD: stand.h,v 1.14 1996/06/21 20:09:06 pk Exp $ */
/*-
* Copyright (c) 1993
@ -90,6 +90,7 @@ struct open_file {
void *f_devdata; /* device specific data */
struct fs_ops *f_ops; /* pointer to file system operations */
void *f_fsdata; /* file system specific data */
off_t f_offset; /* current file offset (F_RAW) */
};
#define SOPEN_MAX 4

6
sys/lib/libsa/write.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: write.c,v 1.5 1995/09/14 23:45:41 pk Exp $ */
/* $NetBSD: write.c,v 1.6 1996/06/21 20:09:07 pk Exp $ */
/*-
* Copyright (c) 1993
@ -64,6 +64,7 @@
* rights to redistribute these changes.
*/
#include <sys/param.h>
#include "stand.h"
ssize_t
@ -82,9 +83,10 @@ write(fd, dest, bcount)
if (f->f_flags & F_RAW) {
twiddle();
errno = (f->f_dev->dv_strategy)(f->f_devdata, F_WRITE,
(daddr_t)0, bcount, dest, &resid);
btodb(f->f_offset), bcount, dest, &resid);
if (errno)
return (-1);
f->f_offset += (bcount - resid);
return (resid);
}
resid = bcount;