PW_UTIL(3)             FreeBSD Library Functions Manual             PW_UTIL(3)

NAME
     pw_copy, pw_dup, pw_edit, pw_equal, pw_fini, pw_init, pw_make,
     pw_make_v7, pw_mkdb, pw_lock, pw_scan, pw_tempname, pw_tmp - functions
     for passwd file handling

LIBRARY
     System Utilities Library (libutil, -lutil)

SYNOPSIS
     #include <pwd.h>
     #include <libutil.h>

     int
     pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *oldpw);

     struct passwd *
     pw_dup(const struct passwd *pw);

     int
     pw_edit(int nosetuid);

     int
     pw_equal(const struct passwd *pw1, const struct passwd *pw2);

     void
     pw_fini(void);

     int
     pw_init(const char *dir, const char *master);

     void
     pw_initpwd(struct passwd *pw);

     char *
     pw_make(const struct passwd *pw);

     char *
     pw_make_v7(const struct passwd *pw);

     int
     pw_mkdb(const char *user);

     int
     pw_lock(void);

     struct passwd *
     pw_scan(const char *line, int flags);

     const char *
     pw_tempname(void);

     int
     pw_tmp(int mfd);

DESCRIPTION
     The pw_copy() function reads a password file from ffd and writes it back
     out to tfd possibly with modifications:

     -   If pw is NULL and oldpw is not NULL, then the record represented by
         oldpw will not be copied (corresponding to user deletion).

     -   If pw and oldpw are not NULL then the record corresponding to pw will
         be replaced by the record corresponding to oldpw.

     -   If pw is set and oldpw is NULL then the record corresponding to pw
         will be appended (corresponding to user addition).

     The pw_copy() function returns -1 in case of failure otherwise 0.

     The pw_dup() function duplicates the struct passwd pointed to by pw and
     returns a pointer to the copy, or NULL in case of failure.  The new
     struct passwd is allocated with malloc(3), and it is the caller's
     responsibility to free it with free(3).

     The pw_edit() function invokes the command specified by the EDITOR
     environment variable (or /usr/bin/vi if EDITOR is not defined) on a
     temporary copy of the master password file created by pw_tmp().  If the
     file was modified, pw_edit() installs it and regenerates the password
     database.  The pw_edit() function returns -1 in case of failure, 0 if the
     file was not modified, and a non-zero positive number if the file was
     modified and successfully installed.

     The pw_equal() function compares two struct passwd and returns 0 if they
     are equal.

     The pw_fini() function destroy the temporary file created by pw_tmp() if
     any, kills any running instance of EDITOR executed by pw_edit() if any,
     and closes the lock created by pw_lock() if any.

     The pw_init() initializes the static variable representing the path to a
     password file.  dir is the directory where the password file is located.
     If set to NULL, it will default to /etc.  master is the name of the
     password file.  If set to NULL? it will default to master.passwd

     The pw_initpwd() function initializes the passwd struct to canonical
     values.  The entire structure is zeroed, then pw_uid and pw_gid are set
     to -1, and all string pointers are set to point at an internally-defined
     zero-length string.

     The pw_make() function creates a properly formatted BSD passwd(5) line
     from a struct passwd, and returns a pointer to the resulting string.  The
     string is allocated with malloc(3), and it is the caller's responsibility
     to free it with free(3).

     The pw_make_v7() function creates a properly formatted UNIX V7 passwd(5)
     line from a struct passwd, and returns a pointer to the resulting string.
     The string is allocated with malloc(3), and it is the caller's
     responsibility to free it with free(3).

     The pw_mkdb() function regenerates the password database by running
     pwd_mkdb(8).  If user only the record corresponding to that user will be
     updated.  The pw_mkdb() function returns 0 in case of success and -1 in
     case of failure.

     The pw_lock() function locks the master password file.  It returns a file
     descriptor to the master password file on success and -1 on failure.

     The pw_scan() function is a wrapper around the internal libc function
     __pw_scan().  It scans the master password file for a line corresponding
     to the line provided and return a struct passwd if it matched an existing
     record.  In case of failure, it returns NULL.  Otherwise, it returns a
     pointer to a struct passwd containing the matching record.  The struct
     passwd is allocated with malloc(3), and it is the caller's responsibility
     to free it with free(3).

     The pw_tempname() function returns the temporary name of the masterfile
     created via pw_tmp().

     The pw_tmp() creates and opens a presumably safe temporary password file.
     If mfd is a file descriptor to an open password file, it will be read and
     written back to the temporary password file.  Otherwise if should be set
     -1.  The pw_tmp() returns an open file descriptor to the temporary
     password file or -1 in case of failure.

HISTORY
     The functions for passwd file handling first appeared in 4.4BSD.

AUTHORS
     Portions of this software were developed for the FreeBSD Project by
     ThinkSec AS and Network Associates Laboratories, the Security Research
     Division of Network Associates, Inc. under DARPA/SPAWAR contract
     N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research program.

     This manual page was written by Baptiste Daroussin <bapt@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6          May 10, 2020          FreeBSD 13.1-RELEASE-p6