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getpwent(3)

NAME

     getpwent, getpwent_r, getpwnam, getpwnam_r, getpwuid, getpwuid_r,
     setpassent, setpwent, endpwent -- password database operations

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

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

     struct passwd *
     getpwent(void);

     int
     getpwent_r(struct passwd *pwd, char *buffer, size_t bufsize,
	 struct passwd **result);

     struct passwd *
     getpwnam(const char *login);

     int
     getpwnam_r(const char *name, struct passwd *pwd, char *buffer,
	 size_t bufsize, struct passwd **result);

     struct passwd *
     getpwuid(uid_t uid);

     int
     getpwuid_r(uid_t uid, struct passwd *pwd, char *buffer, size_t bufsize,
	 struct passwd **result);

     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 */
     intended for programs that wish to process the complete list of users.

     The functions getpwent_r(), getpwnam_r(), and getpwuid_r() are thread-
     safe versions of getpwent(), getpwnam(), and getpwuid(), respectively.
     The caller must provide storage for the results of the search in the pwd,
     buffer, bufsize, and result arguments.  When these functions are success-
     ful, the pwd argument will be filled-in, and a pointer to that argument
     will be stored in result.	If an entry is not found or an error occurs,
     result will be set to NULL.

     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 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 or NULL if the entry is not
     found or if an error occurs.  If an error does occur, errno will be set.
     Note that programs must explicitly set errno to zero before calling any
     of these functions if they need to distinguish between a non-existent
     entry and an error.  The functions getpwent_r(), getpwnam_r(), and
     getpwuid_r() return 0 if no error occurred, or an error number to indi-
     cate failure.  It is not an error if a matching entry is not found.
     (Thus, if result is NULL and the return value is 0, no matching entry
     exists.)

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

ERRORS

     These routines may fail for any of the errors specified in open(2),
     dbopen(3), socket(2), and connect(2), in addition to the following:

     [ERANGE]		The buffer specified by the buffer and bufsize argu-
			ments was insufficiently sized to store the result.
			The caller should retry with a larger buffer.

FILES

     /etc/pwd.db	 The insecure password database file
     /etc/spwd.db	 The secure password database file
     The getpwent(), getpwnam(), getpwuid(), setpwent(), and endpwent() func-
     tions appeared in Version 7 AT&T UNIX.  The setpassent() function
     appeared in 4.3BSD-Reno.  The getpwent_r(), getpwnam_r(), and
     getpwuid_r() functions appeared in FreeBSD 5.1.

STANDARDS

     The getpwent(), getpwnam(), getpwnam_r(), getpwuid(), getpwuid_r(),
     setpwent(), and endpwent() functions conform to ISO/IEC 9945-1:1996
     (``POSIX.1'').

COMPATIBILITY

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

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.

     The functions getpwent(), getpwent_r(), endpwent(), setpassent(), and
     setpwent() are fairly useless in a networked environment and should be
     avoided, if possible.  The getpwent() and getpwent_r() functions make no
     attempt to suppress duplicate information if multiple sources are speci-
     fied in nsswitch.conf(5).

FreeBSD 5.4			April 16, 2003			   FreeBSD 5.4

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