Not only did Prop. 64 make pot legal in California, it also has a pathway to re-sentence past convictions : YouShouldKnow

So I was watching Vice News Tonight, and they had a little segment on this. Might help some people get their lives back on track. Under the measure, individuals serving sentences for activities that are made legal or are subject to lesser penalties under the measure would be eligible for resentencing. An offender serving a jail or prison term for growing or selling marijuana could have their sentence reduced. Qualifying individuals would be resentenced to whatever punishment they would have received under the measure. Resentenced individuals currently in jail or prison would be subject to community supervision for up to one year following their release, unless a court removes that requirement. Individuals who have completed sentences for crimes that are reduced by the measure could apply to the courts to have their criminal records changed.