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GETPWENT(3)	       FreeBSD Library Functions 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 */ int pw_fields; /* internal: fields filled in */ }; 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 It is dangerous for long-running programs to keep the file descriptors open as the database will become out of date if it is updated while the program is running.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 encrypted password will be returned, otherwise, the password field of the returned structure will point to the string `*'. YP/NIS INTERACTION When the yp(8) 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 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), passwd(5), pwd_mkdb(8), vipw(8), yp(8)

HISTORY

The getpwent(), getpwnam(), getpwuid(), setpwent(), and endpwent() func- tions appeared in Version 7 AT&T UNIX. The setpassent() function appeared in 4.3BSD-Reno.

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. FreeBSD 4.9 September 20, 1994 FreeBSD 4.9


Федотов А.М. Введение в Internet