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/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright (c) 2018 by Delphix. All rights reserved.
*/
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
static int bsize = 0;
static int count = 0;
static char *ifile = NULL;
static char *ofile = NULL;
static int stride = 0;
static int seek = 0;
static char *execname = "stride_dd";
static void usage(void);
static void parse_options(int argc, char *argv[]);
static void
usage(void)
{
(void) fprintf(stderr,
"usage: %s -i inputfile -o outputfile -b blocksize -c count \n"
" -s stride [ -k seekblocks]\n"
"\n"
"Simplified version of dd that supports the stride option.\n"
"A stride of n means that for each block written, n - 1 blocks\n"
"are skipped in both the input and output file. A stride of 1\n"
"means that blocks are read and written consecutively.\n"
"All numeric parameters must be integers.\n"
"\n"
" inputfile: File to read from\n"
" outputfile: File to write to\n"
" blocksize: Size of each block to read/write\n"
" count: Number of blocks to read/write\n"
" stride: Read/write a block then skip (stride - 1) blocks\n"
" seekblocks: Number of blocks to skip at start of output\n",
execname);
(void) exit(1);
}
static void
parse_options(int argc, char *argv[])
{
int c;
int errflag = 0;
execname = argv[0];
extern char *optarg;
extern int optind, optopt;
while ((c = getopt(argc, argv, ":b:c:i:o:s:k:")) != -1) {
switch (c) {
case 'b':
bsize = atoi(optarg);
break;
case 'c':
count = atoi(optarg);
break;
case 'i':
ifile = optarg;
break;
case 'o':
ofile = optarg;
break;
case 's':
stride = atoi(optarg);
break;
case 'k':
seek = atoi(optarg);
break;
case ':':
(void) fprintf(stderr,
"Option -%c requires an operand\n", optopt);
errflag++;
break;
case '?':
default:
(void) fprintf(stderr,
"Unrecognized option: -%c\n", optopt);
errflag++;
break;
}
if (errflag) {
(void) usage();
}
}
if (bsize <= 0 || count <= 0 || stride <= 0 || ifile == NULL ||
ofile == NULL || seek < 0) {
(void) fprintf(stderr,
"Required parameter(s) missing or invalid.\n");
(void) usage();
}
}
int
main(int argc, char *argv[])
{
int i;
int ifd;
int ofd;
void *buf;
int c;
parse_options(argc, argv);
ifd = open(ifile, O_RDONLY);
if (ifd == -1) {
(void) fprintf(stderr, "%s: %s: ", execname, ifile);
perror("open");
exit(2);
}
ofd = open(ofile, O_WRONLY | O_CREAT, 0666);
if (ofd == -1) {
(void) fprintf(stderr, "%s: %s: ", execname, ofile);
perror("open");
exit(2);
}
/*
* We use valloc because some character block devices expect a
* page-aligned buffer.
*/
int err = posix_memalign(&buf, 4096, bsize);
if (err != 0) {
(void) fprintf(stderr,
"%s: %s\n", execname, strerror(err));
exit(2);
}
if (seek > 0) {
if (lseek(ofd, seek * bsize, SEEK_CUR) == -1) {
perror("output lseek");
exit(2);
}
}
for (i = 0; i < count; i++) {
c = read(ifd, buf, bsize);
if (c != bsize) {
perror("read");
exit(2);
}
if (c != bsize) {
if (c < 0) {
perror("read");
} else {
(void) fprintf(stderr,
"%s: unexpected short read, read %d "
"bytes, expected %d\n", execname,
c, bsize);
}
exit(2);
}
c = write(ofd, buf, bsize);
if (c != bsize) {
if (c < 0) {
perror("write");
} else {
(void) fprintf(stderr,
"%s: unexpected short write, wrote %d "
"bytes, expected %d\n", execname,
c, bsize);
}
exit(2);
}
if (stride > 1) {
if (lseek(ifd, (stride - 1) * bsize, SEEK_CUR) == -1) {
perror("input lseek");
exit(2);
}
if (lseek(ofd, (stride - 1) * bsize, SEEK_CUR) == -1) {
perror("output lseek");
exit(2);
}
}
}
free(buf);
(void) close(ofd);
(void) close(ifd);
return (0);
}
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