#include <u.h>#include <libc.h> void	split(char *, char **, char **);int	samefile(char *, char *);int	mv(char *from, char *todir, char *toelem);int	copy1(int fdf, int fdt, char *from, char *to);void	hardremove(char *); voidmain(int argc, char *argv[]){	int i;	Dir dirto, dirfrom;	char *todir, *toelem; 	if(argc<3){		fprint(2, "usage: mv fromfile tofile\n");		fprint(2, "	  mv fromfile ... todir\n");		exits("bad usage");	}	if(dirstat(argv[argc-1], &dirto) >= 0 && (dirto.mode&CHDIR)){		if(argc == 3 && dirstat(argv[1], &dirfrom) >= 0 &&				(dirfrom.mode&CHDIR)){			split(argv[argc-1], &todir, &toelem);		}else{			todir = argv[argc-1];			toelem = 0;	/* toelem will be fromelem */		}	}else		split(argv[argc-1], &todir, &toelem);	if(argc>3 && toelem != 0){		fprint(2, "mv: %s not a directory\n", argv[argc-1]);		exits("bad usage");	}	for(i=1; i < argc-1; i++)		if (mv(argv[i], todir, toelem) < 0)			exits("failure");	exits(0);} intmv(char *from, char *todir, char *toelem){	Dir dirb, dirt;	char toname[1024], fromname[1024];	int fdf, fdt, i, j;	int stat;	char *fromdir, *fromelem; 	if(dirstat(from, &dirb)!=0){		fprint(2, "mv: can't stat %s: ", from);		perror("");		return -1;	}	strncpy(fromname, from, sizeof fromname);	split(from, &fromdir, &fromelem);	if(toelem == 0)		toelem = fromelem;	i = strlen(toelem);	if(i==0){		fprint(2, "mv: null last name element moving %s\n", fromname);		return -1;	}	if(i >= NAMELEN){		fprint(2, "mv: name too big: %s\n", toelem);		return -1;	}	j = strlen(todir);	if(i + j + 2 > sizeof toname){		fprint(2, "mv: path too big: %s/%s\n", todir, toelem);		return -1;	}	memmove(toname, todir, j);	toname[j] = '/';	memmove(toname+j+1, toelem, i);	toname[i+j+1] = 0;	if(samefile(fromdir, todir)){		if(samefile(fromname, toname)){			fprint(2, "mv: %s and %s are the same\n", fromname, toname);			return -1;		}		if(dirstat(toname, &dirt) == 0)			hardremove(toname);		strcpy(dirb.name, toelem);		if(dirwstat(fromname, &dirb) >= 0)			return 0;		if(dirb.mode&CHDIR){			fprint(2, "mv: can't rename directory %s: ", fromname);			perror("");			return -1;		}	}	/*	 * Renaming won't work --- have to copy	 */	if(dirb.mode&CHDIR){		fprint(2, "mv: %s is a directory, not copied to %s\n", fromname, toname);		return -1;	}	fdf = open(fromname, OREAD);	if(fdf<0){		fprint(2, "mv: can't open %s:", fromname);		perror("");		return -1;	}	if(dirstat(toname, &dirt)==0 && (dirt.mode&CHAPPEND))		hardremove(toname);	/* because create() won't truncate file */	fdt = create(toname, OWRITE, dirb.mode);	if(fdt < 0){		fprint(2, "mv: can't create %s:", toname);		perror("");		close(fdf);		return -1;	}	if ((stat = copy1(fdf, fdt, fromname, toname)) != -1)		if (remove(fromname) < 0) {			fprint(2, "mv: can't remove %s", fromname);			perror("");			return -1;		}	close(fdf);	close(fdt);	return stat;} intcopy1(int fdf, int fdt, char *from, char *to){	char buf[8192];	long n, n1; 	for(;;) {		n = read(fdf, buf, sizeof buf);		if(n >= 0) {			if(n == 0)				break;			n1 = write(fdt, buf, n);			if(n1 != n) {				fprint(2, "mv: error writing %s:", to);				perror("");				return -1;			}		}	}	if(n < 0) {		fprint(2, "mv: error reading %s:", from);		perror("");		return -1;	}	return 0;} voidsplit(char *name, char **pdir, char **pelem){	char *s; 	s = utfrrune(name, '/');	if(s){		*s = 0;		*pelem = s+1;		*pdir = name;	}else if(strcmp(name, "..") == 0){		*pdir = "..";		*pelem = ".";	}else{		*pdir = ".";		*pelem = name;	}} intsamefile(char *a, char *b){	Dir da, db; 	if(strcmp(a, b) == 0)		return 1;	if(dirstat(a, &da) < 0 || dirstat(b, &db) < 0)		return 0;	return (da.qid.path==db.qid.path && da.qid.vers==db.qid.vers &&		da.dev==db.dev && da.type==db.type);} voidhardremove(char *a){	if(remove(a) == -1){		fprint(2, "mv: can't remove %s\n", a);		exits("mv");	}	do; while(remove(a) != -1);}