getpwnam(3) - NetBSD Manual Pages

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GETPWENT(3)               NetBSD Programmer's Manual               GETPWENT(3)


NAME

     getpwent, getpwnam, getpwuid, setpassent, setpwent, endpwent - password
     database operations


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <sys/types.h>
     #include <pwd.h>

     struct passwd *
     getpwent(void);

     struct passwd *
     getpwnam(const char *login);

     struct passwd *
     getpwuid(uid_t uid);

     int
     setpassent(int stayopen);

     void
     setpwent(void);

     void
     endpwent(void);


DESCRIPTION

     These functions operate on the password database file which is described
     in passwd(5).  Each entry in the database is defined by the structure
     passwd found in the include file <pwd.h>:

           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 getpwnam() and getpwuid() search the password database for
     the given login name or user uid, respectively, always returning the
     first one encountered.

     The getpwent() function sequentially reads the password database and is
     intended for programs that wish to process the complete list of users.

     The setpassent() function accomplishes two purposes.  First, it causes
     getpwent() to ``rewind'' to the beginning of the database.  Additionally,
     if stayopen is non-zero, file descriptors are left open, significantly
     speeding up subsequent accesses for all of the functions.  (This latter
     functionality is unnecessary for getpwent() 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     open as the database will become out of date if it is updated while the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 setpwent() function is equivalent to setpassent() with an argument of
     zero.

     The endpwent() function closes any open files.

     These functions 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 `*'.


RETURN VALUES

     The functions getpwent(), getpwnam(), and getpwuid(), 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 setpassent() function returns 0
     on failure and 1 on success.  The endpwent() and setpwent() functions
     have no return value.


FILES

     /etc/pwd.db         The insecure password database file
     /etc/spwd.db        The secure password database file
     /etc/master.passwd  The current password file
     /etc/passwd         A Version 7 format password file


SEE ALSO

     getlogin(2), getgrent(3), nsswitch.conf(5), passwd(5), pwd_mkdb(8),
     vipw(8)


STANDARDS

     The getpwnam() and getpwuid() functions conform to IEEE Std1003.1-1990
     (``POSIX'').


HISTORY

     The getpwent, getpwnam, getpwuid, setpwent, and endpwent functions ap-
     peared in Version 7 AT&T UNIX.  The setpassent function appeared in
     4.3BSD-Reno.


BUGS

     The functions getpwent(), getpwnam(), and getpwuid(), leave their results
     in an internal static object and return a pointer to that object. Subse-
     quent calls to any of these functions will modify the same object.

     The functions getpwent(), endpwent(), setpassent(), and setpwent() are
     fairly useless in a networked environment and should be avoided, if pos-
     sible.  getpwent() makes no attempt to suppress duplicate information if
     multiple sources are specified in nsswitch.conf(5)


COMPATIBILITY

     The historic function setpwfile() which allowed the specification of al-
     ternative password databases, has been deprecated and is no longer avail-
     able.

NetBSD 1.4                      April 25, 1999                               2