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/*
* copy_sparse.c -- copy a very large sparse files efficiently
* (requires root privileges)
*
* Copyright 2003, 2004 by Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#ifndef __linux__
#include <stdio.h>
#include <stdlib.h>
int main(void) {
fputs("This program is only supported on Linux!\n", stderr);
exit(EXIT_FAILURE);
}
#else
#define _LARGEFILE64_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>
#include <errno.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else
extern char *optarg;
extern int optind;
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/vfs.h>
#include <sys/ioctl.h>
#include <linux/fd.h>
int verbose = 0;
#define FIBMAP _IO(0x00,1) /* bmap access */
#define FIGETBSZ _IO(0x00,2) /* get the block size used for bmap */
static unsigned long get_bmap(int fd, unsigned long block)
{
int ret;
unsigned long b;
b = block;
ret = ioctl(fd, FIBMAP, &b);
if (ret < 0) {
if (errno == EPERM) {
fprintf(stderr, "No permission to use FIBMAP ioctl; must have root privileges\n");
exit(1);
}
perror("FIBMAP");
}
return b;
}
static int full_read(int fd, char *buf, size_t count)
{
int got, total = 0;
int pass = 0;
while (count > 0) {
got = read(fd, buf, count);
if (got == -1) {
if ((errno == EINTR) || (errno == EAGAIN))
continue;
return total ? total : -1;
}
if (got == 0) {
if (pass++ >= 3)
return total;
continue;
}
pass = 0;
buf += got;
total += got;
count -= got;
}
return total;
}
static void copy_sparse_file(const char *src, const char *dest)
{
struct stat64 fileinfo;
long lb, i, fd, ofd, bs, block, numblocks;
ssize_t got, got2;
off64_t offset = 0, should_be;
char *buf;
if (verbose)
printf("Copying sparse file from %s to %s\n", src, dest);
if (strcmp(src, "-")) {
if (stat64(src, &fileinfo) < 0) {
perror("stat");
exit(1);
}
if (!S_ISREG(fileinfo.st_mode)) {
printf("%s: Not a regular file\n", src);
exit(1);
}
fd = open(src, O_RDONLY | O_LARGEFILE);
if (fd < 0) {
perror("open");
exit(1);
}
if (ioctl(fd, FIGETBSZ, &bs) < 0) {
perror("FIGETBSZ");
close(fd);
exit(1);
}
if (bs < 0) {
printf("%s: Invalid block size: %ld\n", src, bs);
exit(1);
}
if (verbose)
printf("Blocksize of file %s is %ld\n", src, bs);
numblocks = (fileinfo.st_size + (bs-1)) / bs;
if (verbose)
printf("File size of %s is %lld (%ld blocks)\n", src,
(long long) fileinfo.st_size, numblocks);
} else {
fd = 0;
bs = 1024;
}
ofd = open(dest, O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0777);
if (ofd < 0) {
perror(dest);
exit(1);
}
buf = malloc(bs);
if (!buf) {
fprintf(stderr, "Couldn't allocate buffer");
exit(1);
}
for (lb = 0; !fd || lb < numblocks; lb++) {
if (fd) {
block = get_bmap(fd, lb);
if (!block)
continue;
should_be = ((off64_t) lb) * bs;
if (offset != should_be) {
if (verbose)
printf("Seeking to %lld\n", should_be);
if (lseek64(fd, should_be, SEEK_SET) == (off_t) -1) {
perror("lseek src");
exit(1);
}
if (lseek64(ofd, should_be, SEEK_SET) == (off_t) -1) {
perror("lseek dest");
exit(1);
}
offset = should_be;
}
}
got = full_read(fd, buf, bs);
if (fd == 0 && got == 0)
break;
if (got == bs) {
for (i=0; i < bs; i++)
if (buf[i])
break;
if (i == bs) {
lseek(ofd, bs, SEEK_CUR);
offset += bs;
continue;
}
}
got2 = write(ofd, buf, got);
if (got != got2) {
printf("short write\n");
exit(1);
}
offset += got;
}
offset = fileinfo.st_size;
if (fstat64(ofd, &fileinfo) < 0) {
perror("fstat");
exit(1);
}
if (fileinfo.st_size != offset) {
lseek64(ofd, offset-1, SEEK_CUR);
buf[0] = 0;
write(ofd, buf, 1);
}
close(fd);
close(ofd);
}
static void usage(const char *progname)
{
fprintf(stderr, "Usage: %s [-v] source_file destination_file\n", progname);
exit(1);
}
int main(int argc, char**argv)
{
int c;
while ((c = getopt(argc, argv, "v")) != EOF)
switch (c) {
case 'v':
verbose++;
break;
default:
usage(argv[0]);
break;
}
if (optind+2 != argc)
usage(argv[0]);
copy_sparse_file(argv[optind], argv[optind+1]);
return 0;
}
#endif
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