others
/* $Id$ */
/* Copyright (c) 2015 Pierre Pronchery <khorben@defora.org> */
/* This file is part of DeforaOS Unix others */
/* 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, version 3 of the License.
*
* This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>. */
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
/* constants */
#define PROGNAME "mksparse"
/* mksparse */
/* private */
/* prototypes */
static int _mksparse(int force, off_t size, int filec, char * const argv[]);
static int _error(char const * message, int ret);
static int _usage(void);
/* functions */
/* mksparse */
static int _mksparse(int force, off_t size, int filec, char * const argv[])
{
int ret = 0;
int flags = force ? O_WRONLY | O_CREAT | O_TRUNC
: O_WRONLY | O_CREAT | O_TRUNC | O_EXCL;
int i;
int fd;
char zero = '\0';
for(i = 0; i < filec; i++)
{
if((fd = open(argv[i], flags, 0666)) < 0)
{
ret = _error(argv[i], 2);
continue;
}
if(size > 0 && (lseek(fd, size - 1, SEEK_SET) != size - 1
|| write(fd, &zero, 1) != 1))
{
ret = _error(argv[i], 2);
unlink(argv[i]);
}
if(close(fd) != 0)
ret = _error(argv[i], 2);
}
return ret;
}
/* error */
static int _error(char const * message, int ret)
{
fputs(PROGNAME ": ", stderr);
perror(message);
return ret;
}
/* usage */
static int _usage(void)
{
fputs("Usage: " PROGNAME " [-f][-s size] file...\n", stderr);
return 1;
}
/* public */
/* functions */
/* main */
int main(int argc, char * argv[])
{
int force = 0;
int o;
off_t size = 0;
char * p;
while((o = getopt(argc, argv, "fs:")) != -1)
switch(o)
{
case 'f':
force = 1;
break;
case 's':
size = strtol(optarg, &p, 0);
if(*optarg == '\0' || *p != '\0')
return _usage();
break;
default:
return _usage();
}
if(optind == argc || size < 0)
return _usage();
return (_mksparse(force, size, argc - optind, &argv[optind]) == 0)
? 0 : 2;
}