lookup.subproj/getpwent.3

   1 .\" Copyright (c) 1988, 1991, 1993
   2 .\"     The Regents of the University of California.  All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 4. Neither the name of the University nor the names of its contributors
  13 .\"    may be used to endorse or promote products derived from this software
  14 .\"    without specific prior written permission.
  15 .\"
  16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26 .\" SUCH DAMAGE.
  27 .\"
  28 .\"     From: @(#)getpwent.3    8.2 (Berkeley) 12/11/93
  29 .\" $FreeBSD: src/lib/libc/gen/getpwent.3,v 1.30 2007/01/09 00:27:54 imp Exp $
  30 .\"
  31 .Dd April 16, 2003
  32 .Dt GETPWENT 3
  33 .Os
  34 .Sh NAME
  35 .Nm getpwent ,
  36 .\".Nm getpwent_r ,
  37 .Nm getpwnam ,
  38 .Nm getpwnam_r ,
  39 .Nm getpwuid ,
  40 .Nm getpwuid_r ,
  41 .Nm setpassent ,
  42 .Nm setpwent ,
  43 .Nm endpwent
  44 .Nd password database operations
  45 .Sh LIBRARY
  46 .Lb libc
  47 .Sh SYNOPSIS
  48 .In sys/types.h
  49 .In pwd.h
  50 .Ft struct passwd *
  51 .Fn getpwent void
  52 .\".Ft int
  53 .\".Fn getpwent_r "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result"
  54 .Ft struct passwd *
  55 .Fn getpwnam "const char *login"
  56 .Ft int
  57 .Fn getpwnam_r "const char *name" "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result"
  58 .Ft struct passwd *
  59 .Fn getpwuid "uid_t uid"
  60 .Ft int
  61 .Fn getpwuid_r "uid_t uid" "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result"
  62 .Ft int
  63 .Fn setpassent "int stayopen"
  64 .Ft void
  65 .Fn setpwent void
  66 .Ft void
  67 .Fn endpwent void
  68 .Sh DESCRIPTION
  69 These functions
  70 .\"operate on the password database file
  71 obtain information from
  72 .Xr DirectoryService 8 ,
  73 including records in
  74 .Pa /etc/passwd
  75 which is described
  76 in
  77 .Xr passwd 5 .
  78 Each entry in the database is defined by the structure
  79 .Vt passwd
  80 found in the include
  81 file
  82 .In pwd.h :
  83 .Bd -literal -offset indent
  84 struct passwd {
  85         char    *pw_name;       /* user name */
  86         char    *pw_passwd;     /* encrypted password */
  87         uid_t   pw_uid;         /* user uid */
  88         gid_t   pw_gid;         /* user gid */
  89         time_t  pw_change;      /* password change time */
  90         char    *pw_class;      /* user access class */
  91         char    *pw_gecos;      /* Honeywell login info */
  92         char    *pw_dir;        /* home directory */
  93         char    *pw_shell;      /* default shell */
  94         time_t  pw_expire;      /* account expiration */
  95         int     pw_fields;      /* internal: fields filled in */
  96 };
  97 .Ed
  98 .Pp
  99 The functions
 100 .Fn getpwnam
 101 and
 102 .Fn getpwuid
 103 search the password database for the given login name or user uid,
 104 respectively, always returning the first one encountered.
 105 .Pp
 106 On Mac OS X, these routines are thread-safe and return a pointer to a
 107 thread-specific data structure.  The contents of this data
 108 structure are automatically released by subsequent calls to
 109 any of these routines on the same thread, or when the thread exits.
 110 .Pp
 111 The
 112 .Fn getpwent
 113 function
 114 sequentially reads the password database and is intended for programs
 115 that wish to process the complete list of users.
 116 .Pp
 117 The functions
 118 .\".Fn getpwent_r ,
 119 .\".Fn getpwnam_r ,
 120 .Fn getpwnam_r
 121 and
 122 .Fn getpwuid_r
 123 are thread-safe versions of
 124 .\".Fn getpwent ,
 125 .\".Fn getpwnam ,
 126 .Fn getpwnam
 127 and
 128 .Fn getpwuid ,
 129 respectively.
 130 The caller must provide storage for the results of the search in
 131 the
 132 .Fa pwd ,
 133 .Fa buffer ,
 134 .Fa bufsize ,
 135 and
 136 .Fa result
 137 arguments.
 138 When these functions are successful, the
 139 .Fa pwd
 140 argument will be filled-in, and a pointer to that argument will be
 141 stored in
 142 .Fa result .
 143 If an entry is not found or an error occurs,
 144 .Fa result
 145 will be set to
 146 .Dv NULL .
 147 .Pp
 148 The
 149 .Fn setpassent
 150 function
 151 accomplishes two purposes.
 152 First, it causes
 153 .Fn getpwent
 154 to ``rewind'' to the beginning of the database.
 155 Additionally, if
 156 .Fa stayopen
 157 is non-zero, file descriptors are left open, significantly speeding
 158 up subsequent accesses for all of the routines.
 159 (This latter functionality is unnecessary for
 160 .Fn getpwent
 161 as it does not close its file descriptors by default.)
 162 .Pp
 163 It is dangerous for long-running programs to keep the file descriptors
 164 open as the database will become out of date if it is updated while the
 165 program is running.
 166 .Pp
 167 The
 168 .Fn setpwent
 169 function
 170 is identical to
 171 .Fn setpassent
 172 with an argument of zero.
 173 .Pp
 174 The
 175 .Fn endpwent
 176 function
 177 closes any open files.
 178 .Pp
 179 .\"These routines have been written to ``shadow'' the password file, e.g.\&
 180 .\"allow only certain programs to have access to the encrypted password.
 181 .\"If the process which calls them has an effective uid of 0, the encrypted
 182 .\"password will be returned, otherwise, the password field of the returned
 183 .\"structure will point to the string
 184 These routines have been written to
 185 .Ql shadow
 186 the password of user records created on Mac OS X 10.3 or later,
 187 by returning a structure whose password field points to the string
 188 .Ql ******** .
 189 Legacy crypt passwords are still returned for user records created on
 190 earlier versions of Mac OS X whose
 191 .Xr DirectoryService 8
 192 .Dt AuthenticationAuthority
 193 attribute contains the value
 194 .Ql ;basic; .
 195 .Sh RETURN VALUES
 196 The functions
 197 .Fn getpwent ,
 198 .Fn getpwnam ,
 199 and
 200 .Fn getpwuid
 201 return a valid pointer to a passwd structure on success
 202 or
 203 .Dv NULL
 204 if the entry is not found or if an error occurs.
 205 If an error does occur,
 206 .Va errno
 207 will be set.
 208 Note that programs must explicitly set
 209 .Va errno
 210 to zero before calling any of these functions if they need to
 211 distinguish between a non-existent entry and an error.
 212 The functions
 213 .\".Fn getpwent_r ,
 214 .\".Fn getpwnam_r ,
 215 .Fn getpwnam_r
 216 and
 217 .Fn getpwuid_r
 218 return 0 if no error occurred, or an error number to indicate failure.
 219 It is not an error if a matching entry is not found.
 220 (Thus, if
 221 .Fa result
 222 is
 223 .Dv NULL
 224 and the return value is 0, no matching entry exists.)
 225 .Pp
 226 The
 227 .Fn setpassent
 228 function returns 0 on failure and 1 on success.
 229 The
 230 .Fn endpwent
 231 and
 232 .Fn setpwent
 233 functions
 234 have no return value.
 235 .Sh FILES
 236 .Bl -tag -width /etc/master.passwd -compact
 237 .\".It Pa /etc/pwd.db
 238 .\"The insecure password database file
 239 .\".It Pa /etc/spwd.db
 240 The secure password database file
 241 .It Pa /etc/master.passwd
 242 The current password file
 243 .It Pa /etc/passwd
 244 A Version 7 format password file
 245 .El
 246 .\".Sh COMPATIBILITY
 247 .\"The historic function
 248 .\".Xr setpwfile 3 ,
 249 .\"which allowed the specification of alternate password databases,
 250 .\"has been deprecated and is no longer available.
 251 .Sh ERRORS
 252 These routines may fail for any of the errors specified in
 253 .Xr open 2 ,
 254 .Xr dbopen 3 ,
 255 .Xr socket 2 ,
 256 and
 257 .Xr connect 2 ,
 258 in addition to the following:
 259 .Bl -tag -width Er
 260 .It Bq Er ERANGE
 261 The buffer specified by the
 262 .Fa buffer
 263 and
 264 .Fa bufsize
 265 arguments was insufficiently sized to store the result.
 266 The caller should retry with a larger buffer.
 267 .El
 268 .Sh SEE ALSO
 269 .Xr getlogin 2 ,
 270 .Xr getgrent 3 ,
 271 .\".Xr nsswitch.conf 5 ,
 272 .Xr passwd 5 ,
 273 .\".Xr pwd_mkdb 8 ,
 274 .\".Xr vipw 8 ,
 275 .Xr DirectoryService 8 ,
 276 .Xr yp 8
 277 .Sh STANDARDS
 278 The
 279 .Fn getpwent ,
 280 .Fn getpwnam ,
 281 .Fn getpwnam_r ,
 282 .Fn getpwuid ,
 283 .Fn getpwuid_r ,
 284 .Fn setpwent ,
 285 and
 286 .Fn endpwent
 287 functions conform to
 288 .St -p1003.1-96 .
 289 .Sh HISTORY
 290 The
 291 .Fn getpwent ,
 292 .Fn getpwnam ,
 293 .Fn getpwuid ,
 294 .Fn setpwent ,
 295 and
 296 .Fn endpwent
 297 functions appeared in
 298 .At v7 .
 299 The
 300 .Fn setpassent
 301 function appeared in
 302 .Bx 4.3 Reno .
 303 The
 304 .\".Fn getpwent_r ,
 305 .\".Fn getpwnam_r ,
 306 .Fn getpwnam_r
 307 and
 308 .Fn getpwuid_r
 309 functions appeared in
 310 .Fx 5.1 .
 311 .Sh BUGS
 312 The functions
 313 .Fn getpwent ,
 314 .Fn getpwnam ,
 315 and
 316 .Fn getpwuid ,
 317 .\"leave their results in an internal static object and return
 318 leave their results in an internal thread-specific memory and return
 319 a pointer to that object.
 320 Subsequent calls to
 321 the same function
 322 will modify the same object.
 323 .\".Pp
 324 .\"The functions
 325 .\".Fn getpwent ,
 326 .\".Fn getpwent_r ,
 327 .\".Fn endpwent ,
 328 .\".Fn setpassent ,
 329 .\"and
 330 .\".Fn setpwent
 331 .\"are fairly useless in a networked environment and should be
 332 .\"avoided, if possible.
 333 .\"The
 334 .\".Fn getpwent
 335 .\"and
 336 .\".Fn getpwent_r
 337 .\"functions
 338 .\"make no attempt to suppress duplicate information if multiple
 339 .\"sources are specified in
 340 .\".Xr nsswitch.conf 5 .