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tme-0.6
/* $Id: posix-tape.c,v 1.1.1.2 2018/04/24 16:42:24 root Exp $ */
/* host/posix/posix-tape.c - implementation of tapes on a POSIX system: */
/*
* Copyright (c) 2003 Matt Fredette
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Matt Fredette.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <tme/common.h>
_TME_RCSID("$Id: posix-tape.c,v 1.1.1.2 2018/04/24 16:42:24 root Exp $");
/* includes: */
#include <tme/generic/tape.h>
#include <tme/threads.h>
#include <fcntl.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/stat.h>
#include <sys/uio.h>
#ifdef HAVE_STDARG_H
#include <stdarg.h>
#else /* HAVE_STDARG_H */
#include <varargs.h>
#endif /* HAVE_STDARG_H */
/* macros: */
/* tape flags: */
#define TME_POSIX_TAPE_FLAG_RO TME_BIT(0)
#define TME_POSIX_TAPE_FLAG_DIRTY TME_BIT(1)
/* the size of the control callout ring: */
#define TME_POSIX_TAPE_CONTROL_RING_SIZE (16)
/* the callout flags: */
#define TME_POSIX_TAPE_CALLOUT_CHECK (0)
#define TME_POSIX_TAPE_CALLOUT_RUNNING TME_BIT(0)
#define TME_POSIX_TAPE_CALLOUTS_MASK (-2)
#define TME_POSIX_TAPE_CALLOUT_CONTROL TME_BIT(1)
/* types: */
/* a posix tape control: */
struct tme_posix_tape_control {
/* the control: */
unsigned int tme_posix_tape_control_which;
};
/* a posix tape segment: */
struct tme_posix_tape_segment {
/* tape segments are kept on a doubly linked list: */
struct tme_posix_tape_segment *tme_posix_tape_segment_next;
struct tme_posix_tape_segment *tme_posix_tape_segment_prev;
/* the filename of this tape segment: */
char *tme_posix_tape_segment_filename;
/* the file descriptor of this tape segment: */
int tme_posix_tape_segment_fd;
/* this is nonzero iff this tape segment is a real tape: */
int tme_posix_tape_segment_real_tape;
};
/* a posix tape: */
struct tme_posix_tape {
/* backpointer to our element: */
struct tme_element *tme_posix_tape_element;
/* our mutex: */
tme_mutex_t tme_posix_tape_mutex;
/* our flags: */
int tme_posix_tape_flags;
/* the tape segments: */
struct tme_posix_tape_segment *tme_posix_tape_segments;
/* the connection: */
struct tme_tape_connection *tme_posix_tape_connection;
/* the callout flags: */
int tme_posix_tape_callout_flags;
/* the control ring buffer: */
struct tme_posix_tape_control tme_posix_tape_controls[TME_POSIX_TAPE_CONTROL_RING_SIZE];
unsigned int tme_posix_tape_control_head;
unsigned int tme_posix_tape_control_tail;
/* the current tape segment: */
struct tme_posix_tape_segment *tme_posix_tape_segment_current;
/* the block sizes: */
unsigned long tme_posix_tape_block_size_min;
unsigned long tme_posix_tape_block_size_max;
unsigned long tme_posix_tape_block_size_fixed;
/* the tape buffer: */
unsigned long tme_posix_tape_buffer_size;
tme_uint8_t *tme_posix_tape_buffer_data;
unsigned long tme_posix_tape_buffer_flags;
unsigned long tme_posix_tape_buffer_count_xfer;
};
/* this allocates the next control in the ring buffer: */
struct tme_posix_tape_control *
_tme_posix_tape_control_new(struct tme_posix_tape *posix_tape)
{
int old_head;
struct tme_posix_tape_control *control;
/* abort if the ring buffer overflows: */
old_head = posix_tape->tme_posix_tape_control_head;
posix_tape->tme_posix_tape_control_head
= ((old_head
+ 1)
& (TME_POSIX_TAPE_CONTROL_RING_SIZE
- 1));
if ((posix_tape->tme_posix_tape_control_head
== posix_tape->tme_posix_tape_control_tail)
&& (posix_tape->tme_posix_tape_connection
!= NULL)) {
abort();
}
/* return the control: */
control = &posix_tape->tme_posix_tape_controls[old_head];
return (control);
}
/* the posix tape callout function. it must be called with the mutex locked: */
static void
_tme_posix_tape_callout(struct tme_posix_tape *posix_tape,
int new_callouts)
{
struct tme_tape_connection *conn_tape;
unsigned int old_tail;
struct tme_posix_tape_control *control;
int callouts, later_callouts;
int rc;
/* add in any new callouts: */
posix_tape->tme_posix_tape_callout_flags |= new_callouts;
/* if this function is already running in another thread, simply
return now. the other thread will do our work: */
if (posix_tape->tme_posix_tape_callout_flags
& TME_POSIX_TAPE_CALLOUT_RUNNING) {
return;
}
/* callouts are now running: */
posix_tape->tme_posix_tape_callout_flags
|= TME_POSIX_TAPE_CALLOUT_RUNNING;
/* assume that we won't need any later callouts: */
later_callouts = 0;
/* loop while callouts are needed: */
for (; ((callouts
= posix_tape->tme_posix_tape_callout_flags)
& TME_POSIX_TAPE_CALLOUTS_MASK); ) {
/* clear the needed callouts: */
posix_tape->tme_posix_tape_callout_flags
= (callouts
& ~TME_POSIX_TAPE_CALLOUTS_MASK);
callouts
&= TME_POSIX_TAPE_CALLOUTS_MASK;
/* get the tape connection: */
conn_tape = posix_tape->tme_posix_tape_connection;
/* if we need to call out a control: */
if (callouts & TME_POSIX_TAPE_CALLOUT_CONTROL) {
/* there must be a control to call out: */
old_tail = posix_tape->tme_posix_tape_control_tail;
assert (old_tail
!= posix_tape->tme_posix_tape_control_head);
control
= &posix_tape->tme_posix_tape_controls[old_tail];
/* unlock the mutex: */
tme_mutex_unlock(&posix_tape->tme_posix_tape_mutex);
/* do the callout: */
rc = TME_OK;
if (conn_tape != NULL) {
switch (control->tme_posix_tape_control_which) {
case TME_TAPE_CONTROL_LOAD:
case TME_TAPE_CONTROL_UNLOAD:
rc = ((*conn_tape->tme_tape_connection_control)
(conn_tape,
control->tme_posix_tape_control_which));
break;
default:
rc = TME_OK;
assert(FALSE);
}
}
/* lock the mutex: */
tme_mutex_lock(&posix_tape->tme_posix_tape_mutex);
/* if the callout was unsuccessful, remember that at some later
time this callout should be attempted again: */
if (rc != TME_OK) {
later_callouts |= TME_POSIX_TAPE_CALLOUT_CONTROL;
}
/* otherwise, this callout was successful: */
else {
/* advance the tail pointer: */
posix_tape->tme_posix_tape_control_tail
= ((old_tail
+ 1)
& (TME_POSIX_TAPE_CONTROL_RING_SIZE
- 1));
/* if there are more controls to callout, call them out now: */
if (posix_tape->tme_posix_tape_control_tail
!= posix_tape->tme_posix_tape_control_head) {
posix_tape->tme_posix_tape_callout_flags
|= TME_POSIX_TAPE_CALLOUT_CONTROL;
}
}
}
}
/* put in any later callouts, and clear that callouts are running: */
posix_tape->tme_posix_tape_callout_flags = later_callouts;
}
/* this closes and frees all tape segments: */
static void
_tme_posix_tape_segments_close(struct tme_posix_tape *posix_tape)
{
struct tme_posix_tape_segment *segment;
/* while we have segments: */
for (; posix_tape->tme_posix_tape_segments != NULL; ) {
/* get the next segment and remove it from the list: */
segment = posix_tape->tme_posix_tape_segments;
posix_tape->tme_posix_tape_segments = segment->tme_posix_tape_segment_next;
/* if the segment file descriptor is open, close it: */
if (segment->tme_posix_tape_segment_fd >= 0) {
close(segment->tme_posix_tape_segment_fd);
}
/* free the segment filename: */
tme_free(segment->tme_posix_tape_segment_filename);
/* free the segment itself: */
tme_free(segment);
}
/* there is no current segment: */
posix_tape->tme_posix_tape_segment_current = NULL;
}
/* this unloads a tape: */
static int
_tme_posix_tape_unload(struct tme_posix_tape *posix_tape)
{
/* close and free all tape segments: */
_tme_posix_tape_segments_close(posix_tape);
return (TME_OK);
}
/* this opens a tape segment and makes it the current segment: */
static int
_tme_posix_tape_segment_open(struct tme_posix_tape *posix_tape,
struct tme_posix_tape_segment *segment)
{
/* there is no current segment: */
posix_tape->tme_posix_tape_segment_current = NULL;
/* open the segment: */
segment->tme_posix_tape_segment_fd
= open(segment->tme_posix_tape_segment_filename,
((posix_tape->tme_posix_tape_flags & TME_POSIX_TAPE_FLAG_RO)
? O_RDONLY
: O_RDWR));
/* if the open failed: */
if (segment->tme_posix_tape_segment_fd < 0) {
return (errno);
}
/* set the current segment: */
posix_tape->tme_posix_tape_segment_current = segment;
return (TME_OK);
}
/* this rewinds a tape: */
static int
_tme_posix_tape_rewind(struct tme_posix_tape *posix_tape)
{
struct tme_posix_tape_segment *segment;
int rc;
/* assume this will succeed: */
rc = TME_OK;
/* if there is a current segment and it's not the first
segment: */
segment = posix_tape->tme_posix_tape_segment_current;
if (segment != NULL
&& segment != posix_tape->tme_posix_tape_segments) {
/* this must be a normal file: */
assert (!segment->tme_posix_tape_segment_real_tape);
/* if the segment is open, close it: */
if (segment->tme_posix_tape_segment_fd >= 0) {
close(segment->tme_posix_tape_segment_fd);
segment->tme_posix_tape_segment_fd = -1;
}
}
/* get the first segment: */
segment = posix_tape->tme_posix_tape_segments;
/* if this is a real tape: */
if (segment->tme_posix_tape_segment_real_tape) {
/* the tape must be open: */
assert (segment->tme_posix_tape_segment_fd >= 0);
/* XXX TBD */
abort();
}
/* otherwise, this is a normal file: */
else {
/* if the file isn't open, open it, else
seek it to the beginning: */
if (segment->tme_posix_tape_segment_fd < 0) {
rc = _tme_posix_tape_segment_open(posix_tape,
segment);
}
else {
if (lseek(segment->tme_posix_tape_segment_fd,
0, SEEK_SET) != 0) {
rc = errno;
}
}
}
return (rc);
}
/* this skips file marks: */
static int
_tme_posix_tape_mark_skip(struct tme_posix_tape *posix_tape,
unsigned int count,
int forward)
{
struct tme_posix_tape_segment *segment;
int rc;
segment = posix_tape->tme_posix_tape_segment_current;
/* if we are at end-of-media, or if we're skipping no marks, do
nothing: */
if (segment == NULL
|| count == 0) {
return (TME_OK);
}
/* this segment must be a normal file: */
assert (!segment->tme_posix_tape_segment_real_tape);
/* if this segment is open, close it: */
if (segment->tme_posix_tape_segment_fd >= 0) {
close(segment->tme_posix_tape_segment_fd);
segment->tme_posix_tape_segment_fd = -1;
}
/* skip the marks: */
for (; segment != NULL && count-- > 0; ) {
segment
= (forward
? segment->tme_posix_tape_segment_next
: segment->tme_posix_tape_segment_prev);
}
/* for now, if we are skipping in reverse we must have a segment -
what do we do otherwise? */
assert (forward || segment != NULL);
/* clear the active segment pointer: */
posix_tape->tme_posix_tape_segment_current = NULL;
/* if we have a segment, open it: */
if (segment != NULL) {
rc = _tme_posix_tape_segment_open(posix_tape,
segment);
assert (rc == TME_OK);
}
/* if we are skipping in reverse, we must leave the tape on the
beginning of media side of the file mark: */
if (!forward) {
rc = (lseek(segment->tme_posix_tape_segment_fd,
0,
SEEK_END) < 0);
assert (rc == 0);
}
return (TME_OK);
}
/* this finishes a transfer. it must be called with the mutex locked: */
static int
_tme_posix_tape_xfer1(struct tme_posix_tape *posix_tape,
int *_flags,
unsigned long *_count_xfer,
unsigned long *_count_bytes,
int xfer_read)
{
struct tme_posix_tape_segment *segment;
unsigned long count_xfer, count_bytes_user, count_bytes_tape;
unsigned long xfer_factor, block_size;
long rc;
/* assume that we will return no flags: */
*_flags = 0;
/* get the transfer count: */
count_xfer = posix_tape->tme_posix_tape_buffer_count_xfer;
/* get any forced block size: */
block_size = posix_tape->tme_posix_tape_block_size_min;
if (block_size != posix_tape->tme_posix_tape_block_size_min) {
block_size = 0;
}
/* if the request is for one or more blocks at a fixed block size: */
if (posix_tape->tme_posix_tape_buffer_flags
& TME_TAPE_FLAG_FIXED) {
/* the device must be in fixed block size mode: */
xfer_factor = posix_tape->tme_posix_tape_block_size_fixed;
if (xfer_factor == 0) {
assert (block_size != 0);
xfer_factor = block_size;
}
else {
assert (block_size == 0
|| block_size == xfer_factor);
block_size = xfer_factor;
}
}
/* otherwise, the request is for one block at a variable block size: */
else {
/* the device might be forcing a block size: */
xfer_factor = 1;
if (block_size == 0) {
block_size = count_xfer;
}
}
/* calculate the byte count for the user: */
count_bytes_user = count_xfer * xfer_factor;
/* calculate the byte count for the tape. this is
the byte count for the user rounded up to the
block size: */
count_bytes_tape = count_bytes_user % block_size;
count_bytes_tape
= (count_bytes_user
+ (count_bytes_tape
? (block_size
- count_bytes_tape)
: 0));
/* get the current segment: */
segment = posix_tape->tme_posix_tape_segment_current;
/* if this is a read: */
if (xfer_read) {
/* if we are out of segments: */
if (segment == NULL) {
/* act like we read zero bytes: */
rc = 0;
}
/* otherwise, do the read: */
else {
/* do the read: */
rc = read(segment->tme_posix_tape_segment_fd,
posix_tape->tme_posix_tape_buffer_data,
count_bytes_user);
/* if this segment is not a real tape, and we're expected to
transfer more bytes than the user requested, seek over the
extra bytes, leaving the medium "positioned after the block": */
if (!segment->tme_posix_tape_segment_real_tape
&& count_bytes_tape > count_bytes_user) {
lseek(segment->tme_posix_tape_segment_fd,
(count_bytes_tape - count_bytes_user),
SEEK_CUR);
}
}
}
/* otherwise, this is a write: */
else {
/* we must have a segment and it must be a real tape: */
assert (segment != NULL
&& segment->tme_posix_tape_segment_real_tape);
/* do the write: */
rc = write(segment->tme_posix_tape_segment_fd,
posix_tape->tme_posix_tape_buffer_data,
count_bytes_user);
}
/* if the transfer got an error: */
if (rc < 0) {
/* return the error: */
/* XXX is this sufficient? */
*_count_bytes = 0;
*_count_xfer = 0;
return (errno);
}
/* otherwise, we transferred some or none of the data: */
else {
/* return the final byte count: */
*_count_bytes = rc;
/* if the request was for one or more blocks at a fixed block size: */
if (posix_tape->tme_posix_tape_buffer_flags
& TME_TAPE_FLAG_FIXED) {
/* return the number of blocks successfully transferred: */
*_count_xfer = (rc / xfer_factor);
}
/* otherwise, the request is for one block at a variable block size: */
else {
/* return the actual size of the block transferred: */
/* if the user asked for what we thought was a whole block, but
we transferred less, how much we did transfer is the actual
block size: */
if (count_bytes_user == block_size
&& (unsigned long) rc < block_size) {
*_count_xfer = rc;
}
/* otherwise, if this segment is a real tape, we don't know how
long the block really was. for now, we just return what we
are using as the block size: */
/* XXX it may be possible to do an ioctl to get the true
residual: */
else if (segment->tme_posix_tape_segment_real_tape) {
*_count_xfer = block_size;
}
/* otherwise, this segment isn't a real tape, so we can return
what we are using as the block size: */
else {
*_count_xfer = block_size;
}
}
/* if we didn't read as much from the tape as we were supposed to: */
if ((unsigned long) rc < count_bytes_tape) {
/* if we read an exact multiple of the block size (including
zero blocks), the read was short because of a file mark.
return the mark (EOF) condition: */
if ((rc % block_size) == 0) {
/* return the mark condition: */
*_flags |= TME_TAPE_FLAG_MARK;
/* if this segment was not a real tape device, skip the file
mark - i.e., move to the next segment: */
if (segment != NULL
&& !segment->tme_posix_tape_segment_real_tape) {
rc = _tme_posix_tape_mark_skip(posix_tape,
1, TRUE);
assert (rc == TME_OK);
}
}
/* otherwise, the read was short because we read a partial
block. return the incorrect length indication (ILI)
condition: */
else {
*_flags |= TME_TAPE_FLAG_ILI;
}
}
}
return (TME_OK);
}
/* this starts a transfer. it must be called with the mutex locked: */
static int
_tme_posix_tape_xfer0(struct tme_posix_tape *posix_tape,
int flags,
unsigned long count_xfer,
unsigned long *_count_bytes)
{
unsigned long xfer_factor, count_bytes;
int old_flags;
unsigned long old_count_xfer, old_count_bytes;
int rc;
/* if the buffer is dirty: */
if (posix_tape->tme_posix_tape_flags
& TME_POSIX_TAPE_FLAG_DIRTY) {
/* write out the buffer: */
rc = _tme_posix_tape_xfer1(posix_tape,
&old_flags,
&old_count_xfer,
&old_count_bytes,
FALSE);
assert (rc == TME_OK);
/* this buffer is no longer dirty: */
posix_tape->tme_posix_tape_flags
&= ~TME_POSIX_TAPE_FLAG_DIRTY;
}
/* set the parameters of this transfer: */
posix_tape->tme_posix_tape_buffer_flags = flags;
posix_tape->tme_posix_tape_buffer_count_xfer = count_xfer;
/* if the request is for one or more blocks at a fixed block size: */
if (posix_tape->tme_posix_tape_buffer_flags
& TME_TAPE_FLAG_FIXED) {
/* it is an error if the device isn't in fixed block size mode: */
xfer_factor = posix_tape->tme_posix_tape_block_size_fixed;
if (xfer_factor == 0) {
xfer_factor = posix_tape->tme_posix_tape_block_size_min;
if (xfer_factor != posix_tape->tme_posix_tape_block_size_max) {
return (EINVAL);
}
}
}
/* otherwise, the request is for one block at a variable block size: */
else {
xfer_factor = 1;
}
/* calculate the byte count: */
count_bytes = count_xfer * xfer_factor;
/* if the buffer isn't big enough: */
if (posix_tape->tme_posix_tape_buffer_size
< count_bytes) {
/* resize the buffer: */
posix_tape->tme_posix_tape_buffer_size
= count_bytes;
posix_tape->tme_posix_tape_buffer_data
= tme_renew(tme_uint8_t,
posix_tape->tme_posix_tape_buffer_data,
posix_tape->tme_posix_tape_buffer_size);
}
/* done: */
*_count_bytes = count_bytes;
return (TME_OK);
}
/* this releases the current buffer: */
static int
_tme_posix_tape_release(struct tme_tape_connection *conn_tape,
int *_flags,
unsigned long *_count_xfer)
{
struct tme_posix_tape *posix_tape;
unsigned long count_bytes;
int rc;
/* recover our data structure: */
posix_tape = (struct tme_posix_tape *) conn_tape->tme_tape_connection.tme_connection_element->tme_element_private;
/* assume that this call will succeed: */
rc = TME_OK;
/* lock the mutex: */
tme_mutex_lock(&posix_tape->tme_posix_tape_mutex);
/* if the buffer is dirty: */
rc = TME_OK;
if (posix_tape->tme_posix_tape_flags
& TME_POSIX_TAPE_FLAG_DIRTY) {
/* write out the buffer: */
rc = _tme_posix_tape_xfer1(posix_tape,
_flags,
_count_xfer,
&count_bytes,
FALSE);
/* this buffer is no longer dirty: */
posix_tape->tme_posix_tape_flags
&= ~TME_POSIX_TAPE_FLAG_DIRTY;
}
/* unlock the mutex: */
tme_mutex_unlock(&posix_tape->tme_posix_tape_mutex);
return (rc);
}
/* this returns a read buffer: */
static int
_tme_posix_tape_read(struct tme_tape_connection *conn_tape,
int *_flags,
unsigned long *_count_xfer,
unsigned long *_count_bytes,
const tme_uint8_t **_buffer)
{
struct tme_posix_tape *posix_tape;
int rc;
/* recover our data structure: */
posix_tape = (struct tme_posix_tape *) conn_tape->tme_tape_connection.tme_connection_element->tme_element_private;
/* lock the mutex: */
tme_mutex_lock(&posix_tape->tme_posix_tape_mutex);
/* start the transfer: */
rc = _tme_posix_tape_xfer0(posix_tape,
*_flags,
*_count_xfer,
_count_bytes);
*_buffer = posix_tape->tme_posix_tape_buffer_data;
/* if the start succeeded, finish the transfer: */
if (rc == TME_OK) {
rc = _tme_posix_tape_xfer1(posix_tape,
_flags,
_count_xfer,
_count_bytes,
TRUE);
}
/* unlock the mutex: */
tme_mutex_unlock(&posix_tape->tme_posix_tape_mutex);
return (rc);
}
/* this returns a write buffer: */
static int
_tme_posix_tape_write(struct tme_tape_connection *conn_tape,
int flags,
unsigned long count_xfer,
unsigned long *_count_bytes,
tme_uint8_t **_buffer)
{
struct tme_posix_tape *posix_tape;
int rc;
/* recover our data structure: */
posix_tape = (struct tme_posix_tape *) conn_tape->tme_tape_connection.tme_connection_element->tme_element_private;
/* lock the mutex: */
tme_mutex_lock(&posix_tape->tme_posix_tape_mutex);
/* start the transfer: */
rc = _tme_posix_tape_xfer0(posix_tape,
flags,
count_xfer,
_count_bytes);
*_buffer = posix_tape->tme_posix_tape_buffer_data;
/* unlock the mutex: */
tme_mutex_unlock(&posix_tape->tme_posix_tape_mutex);
return (rc);
}
/* the tape control handler: */
#ifdef HAVE_STDARG_H
static int _tme_posix_tape_control(struct tme_tape_connection *conn_tape,
unsigned int control,
...)
#else /* HAVE_STDARG_H */
static int _tme_posix_tape_control(conn_tape, control, va_alist)
struct tme_tape_connection *conn_tape;
unsigned int control;
va_dcl
#endif /* HAVE_STDARG_H */
{
struct tme_posix_tape *posix_tape;
unsigned long *sizes;
const unsigned long *csizes;
unsigned int count;
va_list control_args;
int *_flags;
int rc;
/* recover our data structure: */
posix_tape = (struct tme_posix_tape *) conn_tape->tme_tape_connection.tme_connection_element->tme_element_private;
/* lock the mutex: */
tme_mutex_lock(&posix_tape->tme_posix_tape_mutex);
/* start the variable arguments: */
#ifdef HAVE_STDARG_H
va_start(control_args, control);
#else /* HAVE_STDARG_H */
va_start(control_args);
#endif /* HAVE_STDARG_H */
/* dispatch on the sequence type: */
switch (control) {
case TME_TAPE_CONTROL_LOAD:
_flags = va_arg(control_args, int *);
*_flags = (posix_tape->tme_posix_tape_segments != NULL);
rc = TME_OK;
break;
case TME_TAPE_CONTROL_UNLOAD:
rc = _tme_posix_tape_unload(posix_tape);
break;
case TME_TAPE_CONTROL_MARK_WRITE:
abort();
case TME_TAPE_CONTROL_DENSITY_GET:
abort();
case TME_TAPE_CONTROL_DENSITY_SET:
abort();
case TME_TAPE_CONTROL_BLOCK_SIZE_GET:
sizes = va_arg(control_args, unsigned long *);
sizes[0] = posix_tape->tme_posix_tape_block_size_min;
sizes[1] = posix_tape->tme_posix_tape_block_size_max;
sizes[2] = posix_tape->tme_posix_tape_block_size_fixed;
rc = TME_OK;
break;
case TME_TAPE_CONTROL_BLOCK_SIZE_SET:
csizes = va_arg(control_args, const unsigned long *);
/* the minimum block size must be less than or equal to
the maximum block size: */
if (csizes[0] > csizes[1]) {
return (EINVAL);
}
/* if we aren't given a fixed block size: */
if (csizes[2] == 0) {
/* if the minimum and maximum block sizes are the same,
we are in fixed block size mode: */
if (csizes[0] == csizes[1]) {
posix_tape->tme_posix_tape_block_size_fixed = csizes[0];
}
/* otherwise, we are not in fixed block size mode: */
else {
posix_tape->tme_posix_tape_block_size_fixed = 0;
}
}
/* otherwise, we are given a fixed block size. it must
be within the minimum and maximum block sizes: */
else {
if (csizes[2] < csizes[0]
|| csizes[2] > csizes[1]) {
return (EINVAL);
}
posix_tape->tme_posix_tape_block_size_fixed = csizes[2];
}
/* set the minimum and maximum block sizes: */
posix_tape->tme_posix_tape_block_size_min = csizes[0];
posix_tape->tme_posix_tape_block_size_max = csizes[1];
rc = TME_OK;
break;
case TME_TAPE_CONTROL_MARK_SKIPF:
case TME_TAPE_CONTROL_MARK_SKIPR:
count = va_arg(control_args, unsigned int);
rc = _tme_posix_tape_mark_skip(posix_tape,
count,
(control
== TME_TAPE_CONTROL_MARK_SKIPF));
break;
case TME_TAPE_CONTROL_REWIND:
rc = _tme_posix_tape_rewind(posix_tape);
break;
default:
abort();
}
/* end the variable arguments: */
va_end(control_args);
/* unlock the mutex: */
tme_mutex_unlock(&posix_tape->tme_posix_tape_mutex);
return (rc);
}
/* our internal command function: */
static int
__tme_posix_tape_command(struct tme_posix_tape *posix_tape,
const char * const * args,
char **_output)
{
struct tme_posix_tape_segment *segment, **_prev;
struct tme_posix_tape_control *control;
struct stat statbuf;
int flags;
int arg_i;
int usage;
int rc;
int new_callouts;
/* assume we won't need any new callouts: */
new_callouts = 0;
/* check the command: */
usage = FALSE;
arg_i = 1;
/* the "load" command: */
if (TME_ARG_IS(args[arg_i], "load")) {
arg_i++;
/* if a tape is currently loaded, it must be unloaded first: */
if (posix_tape->tme_posix_tape_segments != NULL) {
tme_output_append_error(_output,
_("%s: tape already loaded; must unload first"),
args[0]);
return (EBUSY);
}
/* check for flags, which must all come before the tape segment
filenames: */
flags = 0;
for (;;) {
/* the "read-only" flag: */
if (TME_ARG_IS(args[arg_i], "read-only")) {
flags |= TME_POSIX_TAPE_FLAG_RO;
arg_i++;
}
else {
break;
}
}
/* all of the remaining arguments must be tape segment filenames.
assume that all segments open successfully: */
rc = TME_OK;
/* open the tape segments: */
segment = NULL;
posix_tape->tme_posix_tape_segments = NULL;
for (_prev = &posix_tape->tme_posix_tape_segments;
;
_prev = &segment->tme_posix_tape_segment_next) {
/* stop if we're out of filenames: */
if (args[arg_i] == NULL) {
break;
}
/* allocate a new tape segment and link it in: */
segment = tme_new0(struct tme_posix_tape_segment, 1);
segment->tme_posix_tape_segment_filename
= tme_strdup(args[arg_i]);
segment->tme_posix_tape_segment_next = NULL;
segment->tme_posix_tape_segment_prev = *_prev;
*_prev = segment;
/* open the segment file: */
segment->tme_posix_tape_segment_fd
= open(segment->tme_posix_tape_segment_filename,
O_RDONLY);
if (segment->tme_posix_tape_segment_fd < 0) {
rc = errno;
break;
}
/* stat the segment file: */
if (fstat(segment->tme_posix_tape_segment_fd,
&statbuf) < 0) {
rc = errno;
break;
}
/* if this is a block device: */
if (S_ISBLK(statbuf.st_mode)) {
tme_output_append_error(_output,
_("cannot use a block device: %s"),
args[arg_i]);
rc = EINVAL;
break;
}
/* if this is a character device: */
else if (S_ISCHR(statbuf.st_mode)) {
/* if this is not the only segment: */
if (posix_tape->tme_posix_tape_segments != segment
|| args[arg_i + 1] != NULL) {
tme_output_append_error(_output,
_("a real device must be the only tape segment: "));
rc = EINVAL;
break;
}
/* this is a real tape: */
segment->tme_posix_tape_segment_real_tape = TRUE;
}
/* otherwise, this is a regular file: */
else {
/* this tape must be read-only: */
flags |= TME_POSIX_TAPE_FLAG_RO;
}
/* if this is not the first segment, close the file: */
if (posix_tape->tme_posix_tape_segments != segment) {
close(segment->tme_posix_tape_segment_fd);
segment->tme_posix_tape_segment_fd = -1;
}
/* advance to the next segment filename: */
arg_i++;
}
/* if we got an error: */
if (rc != TME_OK) {
/* append any segment filename to the error: */
if (segment != NULL) {
tme_output_append_error(_output,
"%s",
segment->tme_posix_tape_segment_filename);
}
/* close and free the segments: */
_tme_posix_tape_segments_close(posix_tape);
}
/* otherwise, if we opened no segments: */
else if (posix_tape->tme_posix_tape_segments == NULL) {
tme_output_append_error(_output,
"%s %s load [read-only] { %s | %s [ .. %s ] }",
_("usage:"),
args[0],
_("DEVICE"),
_("FILENAME"),
_("FILENAME"));
rc = EINVAL;
}
/* otherwise, a tape has now been loaded: */
else {
/* a tape has now been loaded: */
posix_tape->tme_posix_tape_flags
= flags;
/* the first segment is still open. make it the current segment: */
posix_tape->tme_posix_tape_segment_current
= posix_tape->tme_posix_tape_segments;
/* call out a LOAD control: */
control = _tme_posix_tape_control_new(posix_tape);
control->tme_posix_tape_control_which = TME_TAPE_CONTROL_LOAD;
new_callouts |= TME_POSIX_TAPE_CALLOUT_CONTROL;
}
}
/* the "unload" command: */
else if (TME_ARG_IS(args[arg_i], "unload")) {
/* if no tape is currently loaded: */
if (posix_tape->tme_posix_tape_segments == NULL) {
tme_output_append_error(_output,
_("%s: no tape loaded"),
args[0]);
return (ENXIO);
}
/* we must have no arguments: */
if (args[arg_i + 1] != NULL) {
tme_output_append_error(_output,
"%s %s unload",
_("usage:"),
args[0]);
return (EINVAL);
}
/* unload the tape: */
_tme_posix_tape_unload(posix_tape);
/* call out an UNLOAD control: */
control = _tme_posix_tape_control_new(posix_tape);
control->tme_posix_tape_control_which = TME_TAPE_CONTROL_UNLOAD;
new_callouts |= TME_POSIX_TAPE_CALLOUT_CONTROL;
rc = TME_OK;
}
/* any other command: */
else {
if (args[arg_i] != NULL) {
tme_output_append_error(_output,
"%s '%s', ",
_("unknown command"),
args[1]);
}
tme_output_append_error(_output,
_("available %s commands: %s"),
args[0],
"load unload");
return (EINVAL);
}
/* make any new callouts: */
_tme_posix_tape_callout(posix_tape, new_callouts);
return (rc);
}
/* our command function: */
static int
_tme_posix_tape_command(struct tme_element *element,
const char * const * args,
char **_output)
{
struct tme_posix_tape *posix_tape;
int rc;
/* recover our data structure: */
posix_tape = (struct tme_posix_tape *) element->tme_element_private;
/* lock the mutex: */
tme_mutex_lock(&posix_tape->tme_posix_tape_mutex);
/* call the internal command function: */
rc = __tme_posix_tape_command(posix_tape,
args,
_output);
/* unlock the mutex: */
tme_mutex_unlock(&posix_tape->tme_posix_tape_mutex);
return (rc);
}
/* this breaks a posix tape connection: */
static int
_tme_posix_tape_connection_break(struct tme_connection *conn,
unsigned int state)
{
abort();
}
/* this makes a posix tape connection: */
static int
_tme_posix_tape_connection_make(struct tme_connection *conn,
unsigned int state)
{
struct tme_posix_tape *posix_tape;
struct tme_tape_connection *conn_tape;
/* recover our data structure: */
posix_tape = (struct tme_posix_tape *) conn->tme_connection_element->tme_element_private;
/* both sides must be tape connections: */
assert(conn->tme_connection_type == TME_CONNECTION_TAPE);
assert(conn->tme_connection_other->tme_connection_type == TME_CONNECTION_TAPE);
/* we're always set up to answer calls across the connection,
so we only have to do work when the connection has gone full,
namely taking the other side of the connection: */
if (state == TME_CONNECTION_FULL) {
/* lock the mutex: */
tme_mutex_lock(&posix_tape->tme_posix_tape_mutex);
/* save this connection to our list of connections: */
conn_tape = (struct tme_tape_connection *) conn->tme_connection_other;
posix_tape->tme_posix_tape_connection = conn_tape;
/* unlock the mutex: */
tme_mutex_unlock(&posix_tape->tme_posix_tape_mutex);
}
return (TME_OK);
}
/* this makes a new connection side for a posix tape: */
static int
_tme_posix_tape_connections_new(struct tme_element *element,
const char * const *args,
struct tme_connection **_conns,
char **_output)
{
struct tme_posix_tape *posix_tape;
struct tme_tape_connection *conn_tape;
struct tme_connection *conn;
/* recover our data structure: */
posix_tape = (struct tme_posix_tape *) element->tme_element_private;
/* if we already have a connection, there's nothing to do: */
if (posix_tape->tme_posix_tape_connection != NULL) {
return (TME_OK);
}
/* create our side of a tape connection: */
conn_tape = tme_new0(struct tme_tape_connection, 1);
conn = &conn_tape->tme_tape_connection;
/* fill in the generic connection: */
conn->tme_connection_next = *_conns;
conn->tme_connection_type = TME_CONNECTION_TAPE;
conn->tme_connection_score = tme_tape_connection_score;
conn->tme_connection_make = _tme_posix_tape_connection_make;
conn->tme_connection_break = _tme_posix_tape_connection_break;
/* fill in the tape connection: */
conn_tape->tme_tape_connection_read
= _tme_posix_tape_read;
conn_tape->tme_tape_connection_write
= _tme_posix_tape_write;
conn_tape->tme_tape_connection_release
= _tme_posix_tape_release;
conn_tape->tme_tape_connection_control
= _tme_posix_tape_control;
/* return the connection side possibility: */
*_conns = conn;
return (TME_OK);
}
/* the new posix tape function: */
TME_ELEMENT_SUB_NEW_DECL(tme_host_posix,tape) {
struct tme_posix_tape *posix_tape;
int flags;
int arg_i;
int usage;
/* check our arguments: */
flags = 0;
arg_i = 1;
usage = FALSE;
/* loop reading our arguments: */
for (;;) {
if (0) {
}
/* if we've run out of arguments: */
else if (args[arg_i + 0] == NULL) {
break;
}
/* this is a bad argument: */
else {
tme_output_append_error(_output,
"%s %s",
args[arg_i],
_("unexpected"));
usage = TRUE;
break;
}
}
if (usage) {
tme_output_append_error(_output,
"%s %s",
_("usage:"),
args[0]);
return (EINVAL);
}
/* start the tape structure: */
posix_tape = tme_new0(struct tme_posix_tape, 1);
posix_tape->tme_posix_tape_element = element;
tme_mutex_init(&posix_tape->tme_posix_tape_mutex);
posix_tape->tme_posix_tape_flags = flags;
posix_tape->tme_posix_tape_segments = NULL;
posix_tape->tme_posix_tape_segment_current = NULL;
/* XXX these are fake values for now: */
posix_tape->tme_posix_tape_block_size_min = 512;
posix_tape->tme_posix_tape_block_size_max = 32768;
posix_tape->tme_posix_tape_block_size_fixed = 0;
/* start the tape buffer. the 16384 isn't magic, it's just a
starting point: */
posix_tape->tme_posix_tape_buffer_size = 16384;
posix_tape->tme_posix_tape_buffer_data
= tme_new(tme_uint8_t,
posix_tape->tme_posix_tape_buffer_size);
/* fill the element: */
element->tme_element_private = posix_tape;
element->tme_element_connections_new = _tme_posix_tape_connections_new;
element->tme_element_command = _tme_posix_tape_command;
return (TME_OK);
}
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.