Summary and Info:
When writing different logfiles, using alpm_logaction, setting a new logfile, alpm crashes.

Steps to Reproduce:
Compiled the attaced test program with
gcc test.c -o test -lalpm
using lalpm 3.1.3

Errors:
produces the error (attached test.log)
According backtrace using (see attached file gdb.log)

Symptom:
-> The first log message is written normally
-> The 2nd isn't written at all (strange)
-> On the 3rd call it crashes when calling alpm_option_set_logfile

Addition:
I don't exactly know how gcc handles this, but as i know free() must not automatically set the pointer to NULL. This would make the check for handle->logfile quite unnecessary, unless it's set to NULL in this function, because except re-initializing alpm there is no possibility to do so.

Just in between: I don't know how GCC handles this, but I know that it's not common that free() sets a pointer to NULL, which would mean the alpm_option_set_logfile needs a handle->logfile = NULL after the free(handle->logfile).