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9 Cards in this Set
- Front
- Back
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What is the password file? |
UNIX requires numerous data files for normal operation, the password file is one of them. -This file is used everytime a user logs in to a UNIX system and everytime someone does a ls-l command. -The password file is stored in /etc/passwd -This file is an ASCII file that is a passwd structure with a bunch of entries. -Entry with the username root, has a user ID of 0. |
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What is an encrypted password? |
A field in the passwd structure that contains a single character as a placeholder. -It is a copy of the user's password that has been put through a one-way encryption algorithm. |
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What is a shadow password? |
The file where new systems store the encrypted password. This file has to contain the username and the encrypted password. -Should not be readable by the world, only login(1) and passd(1) need access. |
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finger(1) |
-this is a user information lookup program. -Displays information about the system users. |
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chfn() & chsh() |
-used to add or change user database information. chfn(): Change information in password file chsh(): change your login shell |
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What does the group file contain? |
/etc/group group name, encrypted password, numerical group ID, and an array of pointers to individual usernames. |
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Functions for program access |
getpwent(void) -We call this function to return the next entry in the password file. Returns a pointer to a structure that is has filled in. setpwent(void) -Rewinds whatever files it uses endpwent(void); -closes these files. -Must remember to use this when using getpwent. |
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Functions to fetch entries from the password file? |
getpwuid(uid_t uid); -Used by the ls(1) program to map the numerical user ID contained in an i-node into a user's login name. getpwnam(const char *name); Used by the login(1) program when we enter our login name. -Both return a pointer to a passwd structure that the functions fill in. |
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Group versions: |
getgrid, getgrnam, getgrent, setgrent, endgrent |
