Hi Paul. Paul Eggert <egg...@cs.ucla.edu> wrote:
> On 12/08/2017 01:16 AM in > <https://sourceware.org/ml/libc-alpha/2017-12/msg00242.html> Arnold > Robbins wrote: > > + /* some malloc()-checkers don't like zero allocations */ > > Which checkers are these? Lord only knows. That change has been in gawk's regex for years and years and I don't remember. So: > Can they be told that 'malloc (0)' is OK? Practically speaking, no. > > + * ADR: valgrind says size can be 0, which then doesn't > > + * free the block of size 0. Harumph. This seems > > + * to work ok, though. > > + */ > > + if (size == 0) > > + { > > + memset(set, 0, sizeof(*set)); > > + return REG_NOERROR; > > + } > > set->alloc = size; > > set->nelem = 0; > > set->elems = re_malloc (int, size); > > For this, how about if we use the corresponding Gnulib fix instead? An > advantage of the Gnulib fix is that it doesn't introduce runtime > overhead when glibc is used. Here is a URL: I think that the runtime overhead is so small that it cannot be measured. I don't want to pull in more gnulib m4 goop for this. The GLIBC guys can do as they wish, of course. :-) > > diff --git a/posix/regexec.c b/posix/regexec.c > > index 2d2bc46..8573765 100644 > > --- a/posix/regexec.c > > +++ b/posix/regexec.c > > @@ -605,7 +605,7 @@ re_search_internal (const regex_t *preg, const char > > *string, int length, > > nmatch -= extra_nmatch; > > > > /* Check if the DFA haven't been compiled. */ > > - if (BE (preg->used == 0 || dfa->init_state == NULL > > + if (BE (preg->used == 0 || dfa == NULL || dfa->init_state == NULL > > || dfa->init_state_word == NULL || dfa->init_state_nl == NULL > > || dfa->init_state_begbuf == NULL, 0)) > > return REG_NOMATCH; > > Why is this change needed? I couldn't see a code path that would trigger > it. I managed once while doing some changes to cause dfa to be NULL. So I added the check. I don't remember what I did. Thanks, Arnold
