gen/getpwent.3

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  32 .\"     From: @(#)getpwent.3    8.2 (Berkeley) 12/11/93
  33 .\" $FreeBSD: src/lib/libc/gen/getpwent.3,v 1.18 2001/10/01 16:08:51 ru Exp $
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  35 .Dd September 20, 1994
  36 .Dt GETPWENT 3
  37 .Os
  38 .Sh NAME
  39 .Nm getpwent ,
  40 .Nm getpwnam ,
  41 .Nm getpwuid ,
  42 .Nm setpassent ,
  43 .Nm setpwent ,
  44 .Nm endpwent
  45 .Nd password database operations
  46 .Sh LIBRARY
  47 .Lb libc
  48 .Sh SYNOPSIS
  49 .In sys/types.h
  50 .In pwd.h
  51 .Ft struct passwd *
  52 .Fn getpwent void
  53 .Ft struct passwd *
  54 .Fn getpwnam "const char *login"
  55 .Ft struct passwd *
  56 .Fn getpwuid "uid_t uid"
  57 .Ft int
  58 .Fn setpassent "int  stayopen"
  59 .Ft int
  60 .Fn setpwent void
  61 .Ft void
  62 .Fn endpwent void
  63 .Sh DESCRIPTION
  64 These functions
  65 operate on the password database file
  66 which is described
  67 in
  68 .Xr passwd 5 .
  69 Each entry in the database is defined by the structure
  70 .Ar passwd
  71 found in the include
  72 file
  73 .Aq Pa pwd.h :
  74 .Bd -literal -offset indent
  75 struct passwd {
  76         char    *pw_name;       /* user name */
  77         char    *pw_passwd;     /* encrypted password */
  78         uid_t   pw_uid;         /* user uid */
  79         gid_t   pw_gid;         /* user gid */
  80         time_t  pw_change;      /* password change time */
  81         char    *pw_class;      /* user access class */
  82         char    *pw_gecos;      /* Honeywell login info */
  83         char    *pw_dir;        /* home directory */
  84         char    *pw_shell;      /* default shell */
  85         time_t  pw_expire;      /* account expiration */
  86         int     pw_fields;      /* internal: fields filled in */
  87 };
  88 .Ed
  89 .Pp
  90 The functions
  91 .Fn getpwnam
  92 and
  93 .Fn getpwuid
  94 search the password database for the given login name or user uid,
  95 respectively, always returning the first one encountered.
  96 .Pp
  97 The
  98 .Fn getpwent
  99 function
 100 sequentially reads the password database and is intended for programs
 101 that wish to process the complete list of users.
 102 .Pp
 103 The
 104 .Fn setpassent
 105 function
 106 accomplishes two purposes.
 107 First, it causes
 108 .Fn getpwent
 109 to ``rewind'' to the beginning of the database.
 110 Additionally, if
 111 .Fa stayopen
 112 is non-zero, file descriptors are left open, significantly speeding
 113 up subsequent accesses for all of the routines.
 114 (This latter functionality is unnecessary for
 115 .Fn getpwent
 116 as it doesn't close its file descriptors by default.)
 117 .Pp
 118 It is dangerous for long-running programs to keep the file descriptors
 119 open as the database will become out of date if it is updated while the
 120 program is running.
 121 .Pp
 122 The
 123 .Fn setpwent
 124 function
 125 is identical to
 126 .Fn setpassent
 127 with an argument of zero.
 128 .Pp
 129 The
 130 .Fn endpwent
 131 function
 132 closes any open files.
 133 .Pp
 134 As of Mac OS X 10.3, there are now different per-user behaviours of
 135 this function, based on the AuthenticationAuthority value
 136 stored for the queried user in DirectoryServices.
 137 .Pp
 138 If the queried user is still a legacy crypt password user or now
 139 has an AuthenticationAuthority value containing ``;basic;'',
 140 these routines will behave in their standard BSD fashion.
 141 These functions will ``shadow'' the password file, e.g.\&
 142 allow only certain programs to have access to the encrypted password.
 143 If the process which calls them has an effective uid of 0, the encrypted
 144 password will be returned, otherwise, the password field of the returned
 145 structure will point to the string
 146 .Ql * .
 147 .Pp
 148 By default in Mac OS X 10.3 and later all users will have an
 149 AuthenticationAuthority with the value ``;ShadowHash;''.
 150 These users will have a visible password value of ``********''.
 151 These functions
 152 will have no access to the encrypted password whatsoever.
 153 Setting or changing
 154 an user password must be done entirely through the DirectoryService APIs
 155 for this default user.
 156 .Pp
 157 There also exists an ``Apple Password Server'' user whose password
 158 value is also ``********'' and with an AuthenticationAuthority that
 159 contains the value ";ApplePasswordServer;" among other data.
 160 There is no getpwnam access to the password for this user either
 161 and again set/change password can be done through the DirectoryService API.
 162 .Pp
 163 Finally in support of local user caching there is a local cached user
 164 whose password is also ``********'' and has an AuthenticationAuthority
 165 value containing ``;LocalCachedUser;'' among other data.
 166 These functions also provide no access to the password for this user
 167 and set/change password functionality is through the DirectoryService API.
 168 .Pp
 169 .Sh RETURN VALUES
 170 The functions
 171 .Fn getpwent ,
 172 .Fn getpwnam ,
 173 and
 174 .Fn getpwuid ,
 175 return a valid pointer to a passwd structure on success
 176 and a null pointer if end-of-file is reached or an error occurs.
 177 The
 178 .Fn setpassent
 179 and
 180 .Fn setpwent
 181 functions return 0 on failure and 1 on success.
 182 The
 183 .Fn endpwent
 184 function
 185 has no return value.
 186 .Sh FILES
 187 .Bl -tag -width /etc/master.passwd -compact
 188 .It Pa /etc/pwd.db
 189 The insecure password database file
 190 .It Pa /etc/spwd.db
 191 The secure password database file
 192 .It Pa /etc/master.passwd
 193 The current password file
 194 .It Pa /etc/passwd
 195 A Version 7 format password file
 196 .El
 197 .Sh SEE ALSO
 198 .Xr getlogin 2 ,
 199 .Xr getgrent 3 ,
 200 .Xr yp 4 ,
 201 .Xr passwd 5 ,
 202 .Xr pwd_mkdb 8 ,
 203 .Xr vipw 8
 204 .Sh HISTORY
 205 The
 206 .Fn getpwent ,
 207 .Fn getpwnam ,
 208 .Fn getpwuid ,
 209 .Fn setpwent ,
 210 and
 211 .Fn endpwent
 212 functions appeared in
 213 .At v7 .
 214 The
 215 .Fn setpassent
 216 function appeared in
 217 .Bx 4.3 Reno .
 218 .Sh COMPATIBILITY
 219 The historic function
 220 .Xr setpwfile 3 ,
 221 which allowed the specification of alternate password databases,
 222 has been deprecated and is no longer available.
 223 .Sh BUGS
 224 The functions
 225 .Fn getpwent ,
 226 .Fn getpwnam ,
 227 and
 228 .Fn getpwuid ,
 229 leave their results in an internal static object and return
 230 a pointer to that object.
 231 Subsequent calls to
 232 the same function
 233 will modify the same object.
 234 .Pp
 235 The functions
 236 .Fn getpwent ,
 237 .Fn endpwent ,
 238 .Fn setpassent ,
 239 and
 240 .Fn setpwent
 241 are fairly useless in a networked environment and should be
 242 avoided, if possible.