getcwd.c

#include <stdio.h>
#include <errno.h>
#include <string.h>

#if 1
char *strerror_r(int, char *, size_t);
#endif

char *getcwd(char *buf, size_t size) {
	if(size == 0) {
		if(buf) {
			errno = EINVAL;
			return NULL;
		}
		//char *path = malloc(2 * sizeof(char));
		//path[0] = '/';
		//path[1] = '\0';
		//return path;
		buf = malloc(2 * sizeof(char));
	} else if(size < 2) {
		errno = ERANGE;
		return NULL;
	}
	buf[0] = '/';
	buf[1] = 0;
	return buf;
}

char *getwd(char *buf) {
#ifndef PATH_MAX
#define PATH_MAX 256
#endif
	char tmpbuf[PATH_MAX];

	if(!buf){
		errno = EINVAL;
		return NULL;
	}
	if(!getcwd(tmpbuf, PATH_MAX)) {
		strerror_r(errno, buf, 1024);
		return NULL;
	}

	/* This is completely unsafe.  Nobody can say how big the user
		provided buffer is.  Perhaps the application and the libc
		disagree about the value of PATH_MAX.  */
	return strcpy(buf, tmpbuf);
}