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/*
* fallocate - utility to use the fallocate system call
*
* Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
* Written by Eric Sandeen <sandeen@redhat.com>
* Karel Zak <kzak@redhat.com>
*
* cvtnum routine taken from xfsprogs,
* Copyright (c) 2003-2005 Silicon Graphics, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <limits.h>
#include <string.h>
#ifndef HAVE_FALLOCATE
# include <sys/syscall.h>
#endif
#if defined(HAVE_LINUX_FALLOC_H) && \
(!defined(FALLOC_FL_KEEP_SIZE) || !defined(FALLOC_FL_PUNCH_HOLE))
# include <linux/falloc.h> /* non-libc fallback for FALLOC_FL_* flags */
#endif
#ifndef FALLOC_FL_KEEP_SIZE
# define FALLOC_FL_KEEP_SIZE 1
#endif
#ifndef FALLOC_FL_PUNCH_HOLE
# define FALLOC_FL_PUNCH_HOLE 2
#endif
#include "nls.h"
#include "strutils.h"
#include "c.h"
#include "closestream.h"
#include "xalloc.h"
static void __attribute__((__noreturn__)) usage(FILE *out)
{
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] <filename>\n"), program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -n, --keep-size don't modify the length of the file\n"
" -p, --punch-hole punch holes in the file\n"
" -d, --dig-holes detect and dig holes\n"
" -o, --offset <num> offset of the (de)allocation, in bytes\n"
" -l, --length <num> length of the (de)allocation, in bytes\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("fallocate(1)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
static loff_t cvtnum(char *s)
{
uintmax_t x;
if (strtosize(s, &x))
return -1LL;
return x;
}
static void xfallocate(int fd, int mode, off_t offset, off_t length)
{
int error;
#ifdef HAVE_FALLOCATE
error = fallocate(fd, mode, offset, length);
#else
error = syscall(SYS_fallocate, fd, mode, offset, length);
#endif
/*
* EOPNOTSUPP: The FALLOC_FL_KEEP_SIZE is unsupported
* ENOSYS: The filesystem does not support sys_fallocate
*/
if (error < 0) {
if ((mode & FALLOC_FL_KEEP_SIZE) && errno == EOPNOTSUPP)
errx(EXIT_FAILURE, _("keep size mode (-n option) unsupported"));
err(EXIT_FAILURE, _("fallocate failed"));
}
}
/*
* Look for chunks of '\0's with size hole_size and when we find them, dig a
* hole on that offset with that size
*/
static void detect_holes(int fd, size_t hole_size)
{
void *zeros;
ssize_t bufsz = hole_size;
void *buf;
off_t offset, end;
/* Create a buffer of '\0's to compare against */
/* XXX: Use mmap() with MAP_PRIVATE so Linux can avoid this allocation */
zeros = mmap(NULL, hole_size, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (zeros == MAP_FAILED)
err(EXIT_FAILURE, _("mmap failed"));
/* buffer to read the file */
buf = xmalloc(bufsz);
end = lseek(fd, 0, SEEK_END);
if (end < 0)
err(EXIT_FAILURE, _("seek failed"));
for (offset = 0; offset + (ssize_t) hole_size <= end; offset += bufsz) {
/* Try to read hole_size bytes */
bufsz = pread(fd, buf, hole_size, offset);
if (bufsz == -1)
err(EXIT_FAILURE, _("read failed"));
/* Always use bufsz, as we may read less than hole_size bytes */
if (memcmp(buf, zeros, bufsz))
continue;
xfallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,
offset, bufsz);
}
if (munmap(zeros, hole_size))
err(EXIT_FAILURE, _("munmap failed"));
free(buf);
}
int main(int argc, char **argv)
{
char *fname;
int c;
int fd;
int mode = 0;
int dig_holes = 0;
loff_t length = -2LL;
loff_t offset = 0;
static const struct option longopts[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
{ "keep-size", 0, 0, 'n' },
{ "punch-hole", 0, 0, 'p' },
{ "dig-holes", 0, 0, 'd' },
{ "offset", 1, 0, 'o' },
{ "length", 1, 0, 'l' },
{ NULL, 0, 0, 0 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((c = getopt_long(argc, argv, "hVnpdl:o:", longopts, NULL)) != -1) {
switch(c) {
case 'h':
usage(stdout);
break;
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
case 'p':
mode |= FALLOC_FL_PUNCH_HOLE;
/* fall through */
case 'n':
mode |= FALLOC_FL_KEEP_SIZE;
break;
case 'd':
dig_holes = 1;
break;
case 'l':
length = cvtnum(optarg);
break;
case 'o':
offset = cvtnum(optarg);
break;
default:
usage(stderr);
break;
}
}
if (dig_holes && mode != 0)
errx(EXIT_FAILURE, _("Can't use -p or -n with --dig-holes"));
if (dig_holes && offset != 0)
errx(EXIT_FAILURE, _("Can't use -o with --dig-holes"));
if (length == -2LL && dig_holes)
length = 32 * 1024;
if (length == -2LL && !dig_holes)
errx(EXIT_FAILURE, _("no length argument specified"));
if (length <= 0)
errx(EXIT_FAILURE, _("invalid length value specified"));
if (offset < 0)
errx(EXIT_FAILURE, _("invalid offset value specified"));
if (optind == argc)
errx(EXIT_FAILURE, _("no filename specified."));
fname = argv[optind++];
if (optind != argc) {
warnx(_("unexpected number of arguments"));
usage(stderr);
}
fd = open(fname, O_RDWR|O_CREAT, 0644);
if (fd < 0)
err(EXIT_FAILURE, _("cannot open %s"), fname);
if (dig_holes)
detect_holes(fd, length);
else
xfallocate(fd, mode, offset, length);
if (close_fd(fd) != 0)
err(EXIT_FAILURE, _("write failed: %s"), fname);
return EXIT_SUCCESS;
}
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