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These functions operate on the password database file which
is described in Each entry in the database is defined by the structure
found in the include file struct passwd { char *pw_name; /* user name
*/
char *pw_passwd; /* encrypted password */
uid_t pw_uid; /* user uid */
gid_t pw_gid; /* user gid */
time_t pw_change; /* password change time */
char *pw_class; /* user access class */
char *pw_gecos; /* Honeywell login info */
char *pw_dir; /* home directory */
char *pw_shell; /* default shell */
time_t pw_expire; /* account expiration */
}; The functions and search the password database for the given login
name or user uid, respectively, always returning the first one encountered.
The function sequentially reads the password database and is intended
for programs that wish to process the complete list of users. The function
accomplishes two purposes. First, it causes to ‘‘rewind’’ to the beginning
of the database. Additionally, if is non-zero, file descriptors are left
open, significantly speeding up subsequent accesses for all of the routines.
(This latter functionality is unnecessary for as it doesn’t close its file
descriptors by default.) It is dangerous for long-running programs to keep
the file descriptors open as the database will become out of date if it
is updated while the program is running. The function is equivalent to
with an argument of zero. The function closes any open files. These routines
have been written to ‘‘shadow’’ the password file, e.g. allow only certain programs
to have access to the encrypted password. If the process which calls them
has an effective uid of 0, the encrypted password will be returned, otherwise,
the password field of the returned structure will point to the string
The functions and return a valid pointer to a passwd structure
on success and a null pointer if end-of-file is reached or an error occurs.
The function returns 0 on failure and 1 on success. The and functions
have no return value.
The insecure password database file The secure
password database file The current password file A Version 7 format password
file
The and functions appeared in The function
appeared in
The functions and leave their results in an internal
static object and return a pointer to that object. Subsequent calls to the
same function will modify the same object. The routines and are fairly
useless in a networked environment and should be avoided, if possible.
The
historic function which allowed the specification of alternate password
databases, has been deprecated and is no longer available.
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