GETPWENT(3)                    Library Routines                    GETPWENT(3)

NAME

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

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);
       int setpwent (void);
       void endpwent (void);

DESCRIPTION

       These functions operate on the password  database  file  which  is  de‐
       scribed  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;     /* real name */
            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 routines.  (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       open as the database will become out of date if it is updated while the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 identical to setpassent with  an  argument  of
       zero.

       The endpwent 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 en‐
       crypted password will be returned, otherwise, the password field of the
       returned structure will point to the string *.

YP/NIS INTERACTION

       When  the yp(4) password database is enabled, the getpwnam and getpwuid
       functions use the YP maps passwd.byname and passwd.byuid, respectively,
       if  the  requested  password  entry is not found in the local database.
       The getpwent function will step through the YP map passwd.byname if the
       entire map is enabled as described in passwd(5).

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 functions setpassent and setpwent re‐
       turn 0 on failure and 1 on success.  The endpwent function has  no  re‐
       turn 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), yp(4), passwd(5), pwd_mkdb(8), vipw(8)

HISTORY

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

COMPATIBILITY

       The  historic function setpwfile(3), which allowed the specification of
       alternate password databases, has been  deprecated  and  is  no  longer
       available.

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 the same function will modify the same object.



GNO                           September 20, 1994                   GETPWENT(3)