On Mon, Jun 13, 2022 at 1:52 PM Richard Henderson < richard.hender...@linaro.org> wrote:
> On 6/12/22 13:48, Warner Losh wrote: > > Implemenet rmdir and __getcwd. Declare __getcwd as extern because > > there's no installed FreeBSD header that has it. It's used internally by > > libc, which doesn't provide an external declaration, but does export the > > symbol. > > Typo in subject: s/-/_/. > Indeed. > > @@ -55,6 +55,7 @@ extern struct iovec *lock_iovec(int type, abi_ulong > target_addr, int count, > > int copy); > > extern void unlock_iovec(struct iovec *vec, abi_ulong target_addr, int > count, > > int copy); > > +extern int __getcwd(char *path, size_t len); > > Do you really want to rely on this export? > Unless it does something special, I'd just declare a local version of the > syscall as you > do with safe_*. > Indeed not. I was just copying what we've been running, but I see now that was unwise. I'll do a safe_syscall directly here since we don't need to call it anywhere else. I'll do a sanity check on our upstream and make sure I can still run my favorite shells, which I believe use this call. > > +/* undocumented __getcwd(char *buf, size_t len) system call */ > > Surely the syscall itself is documented? > One would think it was documented, but there's no man page for it and the getcwd() call has some extensions that it implements, plus there's some weird special cases that __getcwd() can sometimes return that getcwd() knows how to unwind (the oddest being that sometimes paths are returned backwards). All these quirks are not, alas, documented in any place except the code. Hence the characterization that this is undocumented :)... I was rather surprised by this when I went looking. Warner
