pack.c

系统迁移的源代码： http://www.diku.dk/hjemmesider/ansatte/jacobg/

#include <stdio.h>
#include <stdlib.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/sendfile.h>

#include <string.h>



struct file {
	char* name;
	size_t size;
	int fd;
	int optional;
};


void stat_files(struct file* files,int num_files)
{
	int i;
	for(i=0; i<num_files;i++)
	{
		struct file* f = &files[i];
		f->fd = open(f->name, O_RDONLY);

		if(f->name && *(f->name) && f->fd>=0)
		{
			struct stat stat;
			fstat(f->fd, &stat);
			f->size = stat.st_size;
			printf("%s size %d\n", f->name, f->size);
		}
		else if(!f->optional)
		{
			printf("no file: '%s'\n",f->name);
			exit(-1);
		}
	}
}

void write_file(FILE* out, struct file* f)
{
	char* d= malloc(f->size);
	if(f->fd>=0)
	{
		printf("sending file %s\n", f->name);
		if(read(f->fd,d,f->size)!=f->size)
		{
			printf("read err\n");
			exit(-1);

		}

		fwrite(d, f->size,1,out);
		free(d);
		close(f->fd);
	}
}

int main(int argc, char** argv)
{
	int args_size;
	int i;
	char cmdline[256];
	int num_pfns = 0x1000;
	struct file files[] = {
		{ "/root/bin/linux_loader", 0,0,0},
		{ "/root/vmlinux", 0,0,0},
		{ "/root/domUinitrd", 0,0,1}
	};

	const int num_files = sizeof(files)/sizeof(struct file);

	FILE* out = fopen("/tmp/out.img","w");

	memset(cmdline,0,sizeof(cmdline));
	strcpy(cmdline,"mem=16M init=/linuxrc root=/dev/ram xencons=ttyS0");

	printf("%d files\n", num_files);
	stat_files(files,num_files);

	fwrite(&files[0].size, sizeof(size_t),1,out);
	write_file( out, &files[0] );

	args_size = sizeof(cmdline) + 3*sizeof(size_t);
	fwrite(&args_size, sizeof(args_size),1,out);

	fwrite(&num_pfns, sizeof(num_pfns),1,out);
	fwrite(cmdline, sizeof(cmdline),1,out);
	fwrite(&files[1].size, sizeof(size_t),1,out);
	fwrite(&files[2].size, sizeof(size_t),1,out);

	for(i=1; i<num_files; i++) write_file( out, &files[i] );

	fclose(out);

	return 0;
}