fallocate.c revision dc18a3b3052c0bd1a6204a06cd9e79c76f6946fa 
1/*
2 * fallocate - utility to use the fallocate system call
3 *
4 * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
5 * Written by Eric Sandeen <sandeen@redhat.com>
6 *
7 * cvtnum routine taken from xfsprogs,
8 * Copyright (c) 2003-2005 Silicon Graphics, Inc.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it would be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software Foundation,
21 * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
22 */
23
24#define _LARGEFILE_SOURCE
25#define _LARGEFILE64_SOURCE
26
27#include <sys/stat.h>
28#include <sys/syscall.h>
29#include <sys/types.h>
30#include <fcntl.h>
31#include <stdio.h>
32#include <stdlib.h>
33#include <unistd.h>
34#include <ctype.h>
35
36// #include <linux/falloc.h>
37#define FALLOC_FL_KEEP_SIZE	0x01
38#define FALLOC_FL_PUNCH_HOLE	0x02 /* de-allocates range */
39
40void usage(void)
41{
42	printf("Usage: fallocate [-npt] [-o offset] -l length filename\n");
43	exit(EXIT_FAILURE);
44}
45
46#define EXABYTES(x)     ((long long)(x) << 60)
47#define PETABYTES(x)    ((long long)(x) << 50)
48#define TERABYTES(x)    ((long long)(x) << 40)
49#define GIGABYTES(x)    ((long long)(x) << 30)
50#define MEGABYTES(x)    ((long long)(x) << 20)
51#define KILOBYTES(x)    ((long long)(x) << 10)
52
53long long
54cvtnum(char *s)
55{
56	long long	i;
57	char		*sp;
58	int		c;
59
60	i = strtoll(s, &sp, 0);
61	if (i == 0 && sp == s)
62		return -1LL;
63	if (*sp == '\0')
64		return i;
65	if (sp[1] != '\0')
66		return -1LL;
67
68	c = tolower(*sp);
69	switch (c) {
70	case 'k':
71		return KILOBYTES(i);
72	case 'm':
73		return MEGABYTES(i);
74	case 'g':
75		return GIGABYTES(i);
76	case 't':
77		return TERABYTES(i);
78	case 'p':
79		return PETABYTES(i);
80	case 'e':
81		return  EXABYTES(i);
82	}
83
84	return -1LL;
85}
86
87int main(int argc, char **argv)
88{
89	int	fd;
90	char	*fname;
91	int	opt;
92	loff_t	length = -2LL;
93	loff_t	offset = 0;
94	int	falloc_mode = 0;
95	int	error;
96	int	tflag = 0;
97
98	while ((opt = getopt(argc, argv, "npl:o:t")) != -1) {
99		switch(opt) {
100		case 'n':
101			/* do not change filesize */
102			falloc_mode = FALLOC_FL_KEEP_SIZE;
103			break;
104		case 'p':
105			/* punch mode */
106			falloc_mode = (FALLOC_FL_PUNCH_HOLE |
107				       FALLOC_FL_KEEP_SIZE);
108			break;
109		case 'l':
110			length = cvtnum(optarg);
111			break;
112		case 'o':
113			offset = cvtnum(optarg);
114			break;
115		case 't':
116			tflag++;
117			break;
118		default:
119			usage();
120		}
121	}
122
123	if (length == -2LL) {
124		printf("Error: no length argument specified\n");
125		usage();
126	}
127
128	if (length <= 0) {
129		printf("Error: invalid length value specified\n");
130		usage();
131	}
132
133	if (offset < 0) {
134		printf("Error: invalid offset value specified\n");
135		usage();
136	}
137
138	if (tflag && (falloc_mode & FALLOC_FL_KEEP_SIZE)) {
139		printf("-n and -t options incompatible\n");
140		usage();
141	}
142
143	if (tflag && offset) {
144		printf("-n and -o options incompatible\n");
145		usage();
146	}
147
148	if (optind == argc) {
149		printf("Error: no filename specified\n");
150		usage();
151	}
152
153	fname = argv[optind++];
154
155	/* Should we create the file if it doesn't already exist? */
156	fd = open(fname, O_WRONLY|O_LARGEFILE);
157	if (fd < 0) {
158		perror("Error opening file");
159		exit(EXIT_FAILURE);
160	}
161
162	if (tflag)
163		error = ftruncate(fd, length);
164	else
165		error = syscall(SYS_fallocate, fd, falloc_mode, offset, length);
166
167	if (error < 0) {
168		perror("fallocate failed");
169		exit(EXIT_FAILURE);
170	}
171
172	close(fd);
173	return 0;
174}
175