asprintf() is a GNU extension that some BSDs have picked up: it does a printf
into a newly allocated chunk of RAM.
Our tor_asprintf() differs from standard asprintf() in that:
- Like our other malloc functions, it asserts on OOM.
- It works on windows.
- It always sets its return-field.
I believe that since we were allocating *cp while holding a mutex,
coverity deduced that *cp must be protected by that mutex, and later
flipped out when we didn't use it that way. If this is so, we can
solve our problems by moving the *cp = tor_strdup(buf) part outside of
the mutex-protected code.
We do this in too many places throughout the code; it's time to start
clamping down.
Also, refactor Karsten's patch to use strchr-then-strndup, rather than
malloc-then-strlcpy-then-strchr-then-clear.
