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Change vndcompress to use a default window size of 512.

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For vnduncompress on nonseekable input, the window size is as large
as it needs to be by default, as before.  Not clear that this is the
right choice -- by default vnduncompress on nonseekable input will
just use unbounded memory unsolicited.
This commit is contained in:
riastradh 2014-01-22 06:18:00 +00:00
parent 120dc04ff6
commit f13ecd80a5
4 changed files with 33 additions and 10 deletions
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2
usr.bin/vndcompress/Makefile
View File

@ -161,7 +161,7 @@ check-pipewindow: smallwindow.cl2
# @echo '# expecting failure...'
# if head -c $$((64 * 1024 * 1024)) < /dev/zero \
# | (ulimit -v $$((139 * 1024)) && \
# ./vndcompress -l 64m -b 512 /dev/stdin /dev/null); then \
# ./vndcompress -w 0 -l 64m -b 512 /dev/stdin /dev/null); then \
# echo 'unexpected pass!' && exit 1; \
# fi
#

11
usr.bin/vndcompress/common.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: common.h,v 1.5 2014/01/22 06:17:25 riastradh Exp $ */
/* $NetBSD: common.h,v 1.6 2014/01/22 06:18:00 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@ -109,7 +109,16 @@
#define MAX_N_BLOCKS \
(MIN(UINT32_MAX, (SIZE_MAX / sizeof(uint64_t))) - 1)
#define MAX_N_OFFSETS (MAX_N_BLOCKS + 1)
/*
* The window size is at most the number of offsets, so it has the same
* maximum bound. The default window size is chosen so that windows
* fit in one 4096-byte page of memory. We could use 64k bytes, or
* st_blksize, to maximize I/O transfer size, but the transfers won't
* be aligned without a lot of extra work.
*/
#define MAX_WINDOW_SIZE MAX_N_OFFSETS
#define DEF_WINDOW_SIZE 512
struct cloop2_header {
char cl2h_magic[128];

10
usr.bin/vndcompress/vndcompress.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vndcompress.c,v 1.21 2014/01/22 06:17:25 riastradh Exp $ */
/* $NetBSD: vndcompress.c,v 1.22 2014/01/22 06:18:00 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: vndcompress.c,v 1.21 2014/01/22 06:17:25 riastradh Exp $");
__RCSID("$NetBSD: vndcompress.c,v 1.22 2014/01/22 06:18:00 riastradh Exp $");
#include <sys/endian.h>
@ -473,12 +473,16 @@ compress_init(int argc, char **argv, const struct options *O,
S->blocksize, S->size);
assert(S->n_blocks <= MAX_N_BLOCKS);
/* Choose a window size. */
const uint32_t window_size = (ISSET(O->flags, FLAG_w)? O->window_size :
DEF_WINDOW_SIZE);
/* Create an offset table for the blocks; one extra for the end. */
__CTASSERT(MAX_N_BLOCKS <= (UINT32_MAX - 1));
S->n_offsets = (S->n_blocks + 1);
__CTASSERT(MAX_N_OFFSETS == (MAX_N_BLOCKS + 1));
__CTASSERT(MAX_N_OFFSETS <= (SIZE_MAX / sizeof(uint64_t)));
offtab_init(&S->offtab, S->n_offsets, O->window_size, S->cloop2_fd,
offtab_init(&S->offtab, S->n_offsets, window_size, S->cloop2_fd,
CLOOP2_OFFSET_TABLE_OFFSET);
/* Attempt to restart a partial transfer if requested. */

20
usr.bin/vndcompress/vnduncompress.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vnduncompress.c,v 1.9 2014/01/22 06:17:34 riastradh Exp $ */
/* $NetBSD: vnduncompress.c,v 1.10 2014/01/22 06:18:00 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: vnduncompress.c,v 1.9 2014/01/22 06:17:34 riastradh Exp $");
__RCSID("$NetBSD: vnduncompress.c,v 1.10 2014/01/22 06:18:00 riastradh Exp $");
#include <sys/endian.h>
@ -114,18 +114,28 @@ vnduncompress(int argc, char **argv, const struct options *O __unused)
__CTASSERT((MAX_N_BLOCKS + 1) == MAX_N_OFFSETS);
const uint32_t n_offsets = (n_blocks + 1);
/* Make sure we can handle it with the requested window size. */
if ((O->window_size != 0) && (O->window_size < n_offsets)) {
/* Choose a working window size. */
uint32_t window_size;
if (ISSET(O->flags, FLAG_w) && (O->window_size < n_offsets)) {
if (lseek(cloop2_fd, 0, SEEK_CUR) == -1) {
if (errno == ESPIPE)
errx(1, "window too small, nonseekable input");
else
err(1, "window too small and lseek failed");
}
window_size = O->window_size;
} else {
if (lseek(cloop2_fd, 0, SEEK_CUR) == -1) {
if (errno != ESPIPE)
warn("lseek");
window_size = 0;
} else {
window_size = DEF_WINDOW_SIZE;
}
}
/* Initialize the offset table and start reading it in. */
offtab_init(&offtab, n_offsets, O->window_size, cloop2_fd,
offtab_init(&offtab, n_offsets, window_size, cloop2_fd,
CLOOP2_OFFSET_TABLE_OFFSET);
offtab_reset_read(&offtab, &err1, &errx1);