Ack. With "our selfs" corrected to "ourselves" in the comment :-)
Linus On Dec 11, 2014 11:59 PM, "Anton Lundin" <gla...@acc.umu.se> wrote: > We rely on samples being NULL if a dc have no samples. Its completely > legal for malloc to return a valid pointer to nowhere for zero sized > malloc, which you can't follow and read what its pointing at. Its only > viable to call free() on. > > In other code, if samples is a valid pointer, we dereference it and look > at the first sample. > > Signed-off-by: Anton Lundin <gla...@acc.umu.se> > --- > dive.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/dive.c b/dive.c > index 8e8330f..4cf532f 100644 > --- a/dive.c > +++ b/dive.c > @@ -602,6 +602,14 @@ void copy_samples(struct divecomputer *s, struct > divecomputer *d) > int nr = s->samples; > d->samples = nr; > d->alloc_samples = nr; > + // We expect to be able to read the memory in the other end of the > pointer > + // if its a valid pointer, so don't expect malloc() to return NULL > for > + // zero-sized malloc, do it our selfs. > + d->sample = NULL; > + > + if(!nr) > + return; > + > d->sample = malloc(nr * sizeof(struct sample)); > if (d->sample) > memcpy(d->sample, s->sample, nr * sizeof(struct sample)); > -- > 2.1.0 > > _______________________________________________ > subsurface mailing list > subsurface@subsurface-divelog.org > http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface >
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