1 /* truncate -- truncate or extend the length of files.
2 Copyright (C) 2008-2012 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by Pádraig Brady
19 This is backwards compatible with the FreeBSD utility, but is more
20 flexible wrt the size specifications and the use of long options,
21 to better fit the "GNU" environment. */
23 #include <config.h> /* sets _FILE_OFFSET_BITS=64 etc. */
26 #include <sys/types.h>
31 #include "stat-size.h"
34 /* The official name of this program (e.g., no 'g' prefix). */
35 #define PROGRAM_NAME "truncate"
37 #define AUTHORS proper_name_utf8 ("Padraig Brady", "P\303\241draig Brady")
39 /* (-c) If true, don't create if not already there */
40 static bool no_create
;
42 /* (-o) If true, --size refers to blocks not bytes */
43 static bool block_mode
;
45 /* (-r) Reference file to use size from */
46 static char const *ref_file
;
48 static struct option
const longopts
[] =
50 {"no-create", no_argument
, NULL
, 'c'},
51 {"io-blocks", no_argument
, NULL
, 'o'},
52 {"reference", required_argument
, NULL
, 'r'},
53 {"size", required_argument
, NULL
, 's'},
54 {GETOPT_HELP_OPTION_DECL
},
55 {GETOPT_VERSION_OPTION_DECL
},
60 { rm_abs
= 0, rm_rel
, rm_min
, rm_max
, rm_rdn
, rm_rup
} rel_mode_t
;
62 /* Set size to the value of STR, interpreted as a decimal integer,
63 optionally multiplied by various values.
64 Return -1 on error, 0 on success.
66 This supports dd BLOCK size suffixes + lowercase g,t,m for bsd compat
67 Note we don't support dd's b=512, c=1, w=2 or 21x512MiB formats. */
69 parse_len (char const *str
, off_t
*size
)
73 e
= xstrtoimax (str
, NULL
, 10, &tmp_size
, "EgGkKmMPtTYZ0");
75 && !(OFF_T_MIN
<= tmp_size
&& tmp_size
<= OFF_T_MAX
))
85 errno
= (e
== LONGINT_OVERFLOW
? EOVERFLOW
: 0);
92 if (status
!= EXIT_SUCCESS
)
96 printf (_("Usage: %s OPTION... FILE...\n"), program_name
);
98 Shrink or extend the size of each FILE to the specified size\n\
100 A FILE argument that does not exist is created.\n\
102 If a FILE is larger than the specified size, the extra data is lost.\n\
103 If a FILE is shorter, it is extended and the extended part (hole)\n\
104 reads as zero bytes.\n\
108 Mandatory arguments to long options are mandatory for short options too.\n\
111 -c, --no-create do not create any files\n\
114 -o, --io-blocks treat SIZE as number of IO blocks instead of bytes\n\
117 -r, --reference=RFILE base size on RFILE\n\
118 -s, --size=SIZE set or adjust the file size by SIZE\n"), stdout
);
119 fputs (HELP_OPTION_DESCRIPTION
, stdout
);
120 fputs (VERSION_OPTION_DESCRIPTION
, stdout
);
123 SIZE may also be prefixed by one of the following modifying characters:\n\
124 '+' extend by, '-' reduce by, '<' at most, '>' at least,\n\
125 '/' round down to multiple of, '%' round up to multiple of.\n"), stdout
);
126 emit_ancillary_info ();
131 /* return true on success, false on error. */
133 do_ftruncate (int fd
, char const *fname
, off_t ssize
, off_t rsize
,
139 if ((block_mode
|| (rel_mode
&& rsize
< 0)) && fstat (fd
, &sb
) != 0)
141 error (0, errno
, _("cannot fstat %s"), quote (fname
));
146 off_t
const blksize
= ST_BLKSIZE (sb
);
147 if (ssize
< OFF_T_MIN
/ blksize
|| ssize
> OFF_T_MAX
/ blksize
)
150 _("overflow in %" PRIdMAX
151 " * %" PRIdMAX
" byte blocks for file %s"),
152 (intmax_t) ssize
, (intmax_t) blksize
,
160 uintmax_t const fsize
= rsize
< 0 ? sb
.st_size
: rsize
;
162 if (rsize
< 0) /* fstat used above to get size. */
164 if (!S_ISREG (sb
.st_mode
) && !S_TYPEISSHM (&sb
))
166 error (0, 0, _("cannot get the size of %s"), quote (fname
));
171 /* Sanity check. Overflow is the only reason I can think
172 this would ever go negative. */
173 error (0, 0, _("%s has unusable, apparently negative size"),
179 if (rel_mode
== rm_min
)
180 nsize
= MAX (fsize
, (uintmax_t) ssize
);
181 else if (rel_mode
== rm_max
)
182 nsize
= MIN (fsize
, (uintmax_t) ssize
);
183 else if (rel_mode
== rm_rdn
)
184 /* 0..ssize-1 -> 0 */
185 nsize
= (fsize
/ ssize
) * ssize
;
186 else if (rel_mode
== rm_rup
)
187 /* 1..ssize -> ssize */
189 /* Here ssize>=1 && fsize>=0 */
190 uintmax_t const overflow
= ((fsize
+ ssize
- 1) / ssize
) * ssize
;
191 if (overflow
> OFF_T_MAX
)
193 error (0, 0, _("overflow rounding up size of file %s"),
201 if (ssize
> OFF_T_MAX
- (off_t
)fsize
)
203 error (0, 0, _("overflow extending size of file %s"),
207 nsize
= fsize
+ ssize
;
215 if (ftruncate (fd
, nsize
) == -1) /* note updates mtime & ctime */
218 _("failed to truncate %s at %" PRIdMAX
" bytes"), quote (fname
),
227 main (int argc
, char **argv
)
229 bool got_size
= false;
231 off_t size
IF_LINT ( = 0);
233 rel_mode_t rel_mode
= rm_abs
;
235 int c
, fd
= -1, oflags
;
238 initialize_main (&argc
, &argv
);
239 set_program_name (argv
[0]);
240 setlocale (LC_ALL
, "");
241 bindtextdomain (PACKAGE
, LOCALEDIR
);
242 textdomain (PACKAGE
);
244 atexit (close_stdout
);
246 while ((c
= getopt_long (argc
, argv
, "cor:s:", longopts
, NULL
)) != -1)
263 /* skip any whitespace */
264 while (isspace (to_uchar (*optarg
)))
285 /* skip any whitespace */
286 while (isspace (to_uchar (*optarg
)))
288 if (*optarg
== '+' || *optarg
== '-')
292 error (0, 0, _("multiple relative modifiers specified"));
293 /* Note other combinations are flagged as invalid numbers */
294 usage (EXIT_FAILURE
);
298 if (parse_len (optarg
, &size
) == -1)
299 error (EXIT_FAILURE
, errno
, _("invalid number %s"),
301 /* Rounding to multiple of 0 is nonsensical */
302 if ((rel_mode
== rm_rup
|| rel_mode
== rm_rdn
) && size
== 0)
303 error (EXIT_FAILURE
, 0, _("division by zero"));
307 case_GETOPT_HELP_CHAR
;
309 case_GETOPT_VERSION_CHAR (PROGRAM_NAME
, AUTHORS
);
312 usage (EXIT_FAILURE
);
319 /* must specify either size or reference file */
320 if (!ref_file
&& !got_size
)
322 error (0, 0, _("you must specify either %s or %s"),
323 quote_n (0, "--size"), quote_n (1, "--reference"));
324 usage (EXIT_FAILURE
);
326 /* must specify a relative size with a reference file */
327 if (ref_file
&& got_size
&& !rel_mode
)
329 error (0, 0, _("you must specify a relative %s with %s"),
330 quote_n (0, "--size"), quote_n (1, "--reference"));
331 usage (EXIT_FAILURE
);
333 /* block_mode without size is not valid */
334 if (block_mode
&& !got_size
)
336 error (0, 0, _("%s was specified but %s was not"),
337 quote_n (0, "--io-blocks"), quote_n (1, "--size"));
338 usage (EXIT_FAILURE
);
340 /* must specify at least 1 file */
343 error (0, 0, _("missing file operand"));
344 usage (EXIT_FAILURE
);
349 /* FIXME: Maybe support getting size of block devices. */
351 if (stat (ref_file
, &sb
) != 0)
352 error (EXIT_FAILURE
, errno
, _("cannot stat %s"), quote (ref_file
));
353 if (!S_ISREG (sb
.st_mode
) && !S_TYPEISSHM (&sb
))
354 error (EXIT_FAILURE
, 0, _("cannot get the size of %s"),
362 oflags
= O_WRONLY
| (no_create
? 0 : O_CREAT
) | O_NONBLOCK
;
363 omode
= S_IRUSR
| S_IWUSR
| S_IRGRP
| S_IWGRP
| S_IROTH
| S_IWOTH
;
365 while ((fname
= *argv
++) != NULL
)
367 if ((fd
= open (fname
, oflags
, omode
)) == -1)
369 /* 'truncate -s0 -c no-such-file' shouldn't gen error
370 'truncate -s0 no-such-dir/file' should gen ENOENT error
371 'truncate -s0 no-such-dir/' should gen EISDIR error
372 'truncate -s0 .' should gen EISDIR error */
373 if (!(no_create
&& errno
== ENOENT
))
375 error (0, errno
, _("cannot open %s for writing"),
385 errors
|= !do_ftruncate (fd
, fname
, size
, rsize
, rel_mode
);
388 error (0, errno
, _("closing %s"), quote (fname
));
394 return errors
? EXIT_FAILURE
: EXIT_SUCCESS
;