What was your plea to? This is important, as it controls whether you are eligible for "Good Time - Work Time" credit. Most folks sentenced to 120 days are eligible for this, meaning they will serve a maximum of 60 days if they stay out of fights ("good behavior") and make themselves available for work at the jail. In terms of how much less time than 60 days the person will serve, that depends upon the prisoner count (how full the jail is), the gender of the prisoner, the age, and the person's medical condition. The prisoner could serve very few days or closer to 60 depending upon these factors. No one on this board can probably give you a more definite answer unless they work in the jail on a daily basis.
The amount of time you're actually likely to do depends on a lot of the factors already described by my colleague. However, it may also be that your county has some early releases going on-- LA County certainly does, but that's not a way to predict whether or not Tehama will. The only people who might have a sense of that are the people who are working in that county regularly, Your best resource for an answer to that question is the lawyer who helped you with your plea.
In general, having to register as a narcotics offender is not a particularly big deal, even in a smaller county. It should not 'last forever.'
Whether or not you can have a passport is really an immigration question. But if you are a US citizen, the answer is yes, you can have a passport. BUT, there may be restrictions placed on your ability to travel as a condition of your probation-- you need to be sure you understand all of the terms and conditions of your probation. If you have any question as to what they are, check with the attorney who helped you with your plea deal.
Any answer provided on Avvo, including this one, is a general answer about a legal question, not specific legal advice. Different lawyers may analyze this or any other matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am licensed in the state of California and the Central District of the Ninth Circuit.
It depends on a lot of factors, as my colleagues have pointed out, but you can count on something close to half of that time. Drug registration is required due to a conviction for specified offenses, but should not be permanent. It generally lasts for five years after you discharge from prison, release from jail or termination of probation. (Health and Safety Code section 11594)