/*
	Copy the directory structure, but not the files
*/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <string>

using namespace std;

static void usage()
{
	fprintf (stderr
		,"copytree source-directory target-directory\n"
		 "\n"
		 "All sub-directory in source-directory are created\n"
		 "with the same permission/ownership in target-directory.\n");
}

static int copytree (const char *src, const char *dst)
{
	int ret = -1;
	DIR *d = opendir (src);
	if (d == NULL){
		fprintf (stderr,"Can't open directory %s (%s)\n",src,strerror(errno));
	}else{
		struct dirent *ent;
		ret = 0;
		while ((ent=readdir(d))!=NULL){
			struct stat64 st;
			string srctmp = string(src) + '/' + ent->d_name;
			string dsttmp = string(dst) + '/' + ent->d_name;
			const char *dtmp = dsttmp.c_str();
			if (stat64 (srctmp.c_str(),&st)==-1){
				// If this is symlink pointing nowhere, we copy the link
				if (lstat64(srctmp.c_str(),&st)==-1){
					// Very strange. The entry exist in the directory but
					// even lstat fails. The system is broken, better bug off.
					fprintf (stderr,"Can't stat file %s (%s)\n",srctmp.c_str()
						,strerror(errno));
					ret = -1;
					break;
				}else if (S_ISLNK(st.st_mode)){
					char lpath[PATH_MAX];
					int len = readlink (srctmp.c_str(),lpath,sizeof(lpath)-1);
					if (len > 0){
						lpath[len] = '\0';
						unlink (dtmp);
						if (symlink(lpath,dtmp)==-1){
							fprintf (stderr,"Can't symlink %s -> %s (%s)\n"
								,dtmp,lpath,strerror(errno));
							ret = -1;
							break;
						}
					}else{
						fprintf (stderr,"Can't readlink %s (%s)\n",srctmp.c_str()
							,strerror(errno));
						ret = -1;
						break;
					}
				}else{
					// Really strange. stat failed, but not lstat
					fprintf (stderr,"Can't stat file %s, but can lstat, but not symlink\n"
						,srctmp.c_str());
					ret = -1;
					break;
				}
			}else if (S_ISDIR(st.st_mode)
				&& strcmp(ent->d_name,".")!=0
				&& strcmp(ent->d_name,"..")!=0){
				// Is is a directory or a symlink
				char lpath[PATH_MAX];
				int len = readlink (srctmp.c_str(),lpath,sizeof(lpath));
				struct stat64 dst;
				if (len > 0){
					lpath[len] = '\0';
					unlink (dtmp);
					if (symlink(lpath,dtmp)==-1){
						fprintf (stderr,"Can't create symlink %s -> %s (%s)\n"
							,lpath,dtmp,strerror(errno));
						ret = -1;
					}
				}else if (lstat64(dtmp,&dst)!=-1){
					if (S_ISDIR(dst.st_mode)){
						// Already there
						if (chown (dtmp,st.st_uid,st.st_gid)==-1){
							fprintf (stderr,"Can't chown directory %s (%s)\n"
								,dtmp,strerror(errno));
							ret = -1;
						}else if (chmod (dtmp,st.st_mode)==-1){
							fprintf (stderr,"Can't chmod sub-directory %s (%s)\n"
								,dtmp,strerror(errno));
							ret = -1;
						}else{
							ret = copytree (srctmp.c_str(),dtmp);
						}
					}else if(S_ISLNK(dst.st_mode)){
					}else{
						fprintf (stderr,"%s already exist but is not a directory nor a symlink\n"
							,dtmp);
						ret = -1;
					}
				}else{
					if (mkdir (dtmp,st.st_mode)==-1){
						fprintf (stderr,"Can't create sub-directory %s (%s)\n"
							,dtmp,strerror(errno));
						ret = -1;
					}else if (chown (dtmp,st.st_uid,st.st_gid)==-1){
						fprintf (stderr,"Can't chown directory %s (%s)\n"
							,dtmp,strerror(errno));
						ret = -1;
					}else{
						ret = copytree (srctmp.c_str(),dtmp);
					}
				}
			}
		}
		closedir (d);
	}
	return ret;
}


int main (int argc, char *argv[])
{
	int ret = -1;
	if (argc != 3){
		usage();
	}else{
		umask(0);
		ret = copytree (argv[1],argv[2]);
	}
	return ret;
}