Utilize Python to control GDB

There's a good article details how to control GDB via Python instead of GDB script, please refer: http://www.linuxjournal.com/article/11027.

However due to time evolves, the Python scripts seems to stop working. The following is a modified one to compatible with the example giving in the article.

#!/usr/local/bin/python
from collections import defaultdict
# A dictionary of mutex:owner
mutexOwners = {}
# A dictionary of blocking mutex:(threads..)
threadBlockers = defaultdict(list)
# Print the threads
#print "Process threads : "
#gdb.execute("info threads")
print "Analysing mutexes..."
# Step through processes running under gdb
def get_frame(hint):
    
    frame = gdb.selected_frame()

    if hint == None:
        return frame
    elif type(hint) == int:
        i = 0
        while i < hint and frame != None:
            pre_frame = frame.older()
            if frame == pre_frame and frame < hint - 1:
                frame = None
                break
            else:
                frame = new_frame
            i += 1
    elif type(hint) == str:
        while frame != None:
            pre_frame = frame.older()
            if frame.name() == hint or pre_frame == frame:
                break
            else:
                frame = pre_frame
    return frame

for process in gdb.inferiors():

    # Step through each thread in the process
    for thread in process.threads():

        # Examine the thread -- is it blocking on a mutex?
        thread.switch()
        frame = get_frame("pthread_mutex_lock")
        
        if frame != None:
            frame.select()

            # Make a note of which thread blocks on which mutex
            mutex = int(gdb.parse_and_eval("$r8"))
            threadBlockers[mutex].append(thread.ptid[0])

            # Make a note of which thread owns this mutex
            if not mutex in mutexOwners:
                v = gdb.parse_and_eval("*$r8").cast(gdb.lookup_type("pthread_mutex_t"))
                mutexOwners[mutex] = v['__data']['__owner']

    # Print the results of the analysis
    for mutex in mutexOwners:
        print "  Mutex 0x%x :" % mutex
        print "     -> held by thread : %d" % mutexOwners[mutex]
        s = ["%d" % t for t in threadBlockers[mutex]]
        print "     -> blocks threads : %s" % ' '.join(s)