- if (!buf) buf = tmp, size = PATH_MAX;
- if (syscall(SYS_getcwd, buf, size) < 0) return 0;
+ if (!buf) {
+ buf = tmp;
+ size = PATH_MAX;
+ } else if (!size) {
+ errno = EINVAL;
+ return 0;
+ }
+ long ret = syscall(SYS_getcwd, buf, size);
+ if (ret < 0)
+ return 0;
+ if (ret == 0 || buf[0] != '/') {
+ errno = ENOENT;
+ return 0;
+ }