On 13 September 2017 at 17:22, Jeff King <peff@xxxxxxxx> wrote: > On Wed, Sep 13, 2017 at 05:18:56PM +0200, demerphq wrote: > >> > Hmph. That is very disturbing. But with that information I should be >> > able to track down the culprit. Thanks for digging. >> >> FWIW, I see that git_config_set_multivar_in_file_gently() uses >> write_in_full() which in turn uses xwrite(), but the latter has the >> following comment on it: >> >> /* >> * xwrite() is the same a write(), but it automatically restarts write() >> * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT >> * GUARANTEE that "len" bytes is written even if the operation is successful. >> */ >> >> I suspect that at this point I am not adding much value here, so I >> will leave it at this. > > No, the problem is in this line: > > if (write_in_full(fd, contents + copy_begin, > copy_end - copy_begin) < > copy_end - copy_begin) > goto write_err_out; > > write_in_full() returns -1 on error (_not_ how many bytes were actually > written). So its return is a signed ssize_t. But the result of the > pointer subtraction "copy_end - copy_begin" is an unsigned ptrdiff_t. > The compiler promotes the signed to an unsigned, so the condition can > never be true (the "-1" becomes the highest possible value). Bah. Good eye. I missed that entirely. > I have the fix, but I'm searching the code base for other instances of > the same error. Yeah, I think there are few just in that file. Thanks for fixing this! cheers, Yves -- perl -Mre=debug -e "/just|another|perl|hacker/"
