Block copy tool for dm-era
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3.6 KiB

/**
* Applies `era_copy` output to a file or block device
*
* Author: Vitaliy Filippov <vitalif@yourcmc.ru>, 2019
* License: GNU GPLv3.0 or later
*/
#define _LARGEFILE64_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#define XML_BUFSIZE 1024
#define COPY_BUFSIZE 0x400000
#define SIGNATURE "ERARANGE"
static void* copy_buffer = NULL;
void apply_blocks(int src, int dst, off64_t start, off64_t length, long long *total, long long *prev_total)
{
off64_t copied = 0;
ssize_t fact = 0, written = 0, fact_write = 0;
if (!copy_buffer)
{
copy_buffer = malloc(COPY_BUFSIZE);
if (!copy_buffer)
{
fprintf(stderr, "Failed to allocate %d bytes\n", COPY_BUFSIZE);
exit(1);
}
}
if (lseek64(dst, start, 0) < 0)
{
fprintf(stderr, "Failed to lseek in output file: %s\n", strerror(errno));
exit(1);
}
while (length > copied)
{
fact = read(src, copy_buffer, length-copied > COPY_BUFSIZE ? COPY_BUFSIZE : length-copied);
if (fact <= 0)
{
fprintf(stderr, "Read error: %s\n", strerror(errno));
exit(1);
}
written = 0;
while (written < fact)
{
fact_write = write(dst, copy_buffer+written, fact-written);
if (fact_write <= 0)
{
fprintf(stderr, "Write error: %s\n", strerror(errno));
exit(1);
}
written += fact_write;
}
copied += fact;
if (total != NULL)
{
*total += fact;
if (*total > *prev_total + 1048576)
{
fprintf(stderr, "\r%lld MB...", *total/1048576);
*prev_total = *total;
}
}
}
}
void read_era_copy_and_apply(int src, int dst, int print_progress)
{
long long sign = 0, start = 0, length = 0;
long long total = 0, prev_total = 0; // for printing progress
long long *ptr_total = NULL, *ptr_prev_total = NULL;
int r;
if (print_progress)
{
setvbuf(stderr, NULL, _IONBF, 0);
ptr_total = &total;
ptr_prev_total = &prev_total;
}
while (1)
{
r = read(src, &sign, 8);
if (r == 0)
{
break;
}
if (r < 8 ||
read(src, &start, 8) < 8 ||
read(src, &length, 8) < 8)
{
if (errno)
fprintf(stderr, "read error: %s\n", strerror(errno));
else
fprintf(stderr, "premature end of file\n");
exit(1);
}
if (sign != *((long long*)SIGNATURE))
{
fprintf(stderr, "era_copy signature does not match\n");
exit(1);
}
apply_blocks(src, dst, start, length, ptr_total, ptr_prev_total);
}
if (print_progress)
{
fprintf(stderr, "\n");
}
}
void era_apply(char *dst_path, int print_progress)
{
struct stat sb;
int dst, flags = O_WRONLY | O_LARGEFILE;
if (stat(dst_path, &sb) == 0)
{
// prevent writing to mounted devices
flags = flags | ((sb.st_mode & S_IFBLK) ? O_EXCL : 0);
}
else
{
if (errno == ENOENT)
{
flags = flags | O_CREAT;
}
else
{
fprintf(stderr, "Failed to stat %s: %s\n", dst_path, strerror(errno));
exit(1);
}
}
dst = open(dst_path, flags, 0644);
if (dst < 0)
{
fprintf(stderr, "Failed to open %s for writing: %s\n", dst_path, strerror(errno));
exit(1);
}
read_era_copy_and_apply(0, dst, print_progress);
// fsync and close
fsync(dst);
close(dst);
}
int main(int narg, char *args[])
{
int print_progress = 0;
if (narg < 2 || ((print_progress = !strcmp(args[1], "--progress")) && narg < 3))
{
fprintf(stderr,
"era_apply - applies era_copy output to a file or block device\n"
"(c) Vitaliy Filippov, 2019+, distributed under the terms of GNU GPLv3.0 or later license\n"
"\n"
"USAGE:\nera_apply [--progress] DESTINATION < era_copy_output.bin\n"
);
exit(1);
}
era_apply(args[print_progress ? 2 : 1], print_progress);
return 0;
}