#include <u.h>#include <libc.h> char*getenv(char *name){	enum { HUNK = 100, };	char *s, *p;	int f, r, n; 	if(name[0]=='\0' || strcmp(name, ".")==0 || strcmp(name, "..")==0 || strchr(name, '/')!=nil	|| strlen(name) >= HUNK-5){		werrstr("bad env name: %s", name);		return nil;	}	if((s = malloc(HUNK)) == nil)		return nil;	snprint(s, HUNK, "/env/%s", name);	n = 0;	r = -1;	f = open(s, OREAD|OCEXEC);	if(f >= 0){		while((r = read(f, s+n, HUNK)) > 0){			n += r;			r = -1;			if((p = realloc(s, n+HUNK)) == nil)				break;			s = p;		}		close(f);	}	if(r < 0 || (p = realloc(s, n+1)) == nil){		free(s);		return nil;	}	s = p;	setmalloctag(s, getcallerpc(&name));	while(n > 0 && s[n-1] == '\0')		n--;	s[n] = '\0';	while(--n >= 0){		if(s[n] == '\0')			s[n] = ' ';	}	return s;}