lookup.subproj/getpwent.3

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  52 .Dd October 26, 2011
  53 .Dt GETPWENT 3
  54 .Os
  55 .Sh NAME
  56 .Nm getpwent ,
  57 .\".Nm getpwent_r ,
  58 .Nm getpwnam ,
  59 .Nm getpwnam_r ,
  60 .Nm getpwuid ,
  61 .Nm getpwuid_r ,
  62 .Nm getpwuuid ,
  63 .Nm getpwuuid_r ,
  64 .Nm setpassent ,
  65 .Nm setpwent ,
  66 .Nm endpwent
  67 .Nd password database operations
  68 .Sh LIBRARY
  69 .Lb libc
  70 .Sh SYNOPSIS
  71 .In sys/types.h
  72 .In pwd.h
  73 .In uuid/uuid.h
  74 .Ft struct passwd *
  75 .Fn getpwent void
  76 .\".Ft int
  77 .\".Fn getpwent_r "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result"
  78 .Ft struct passwd *
  79 .Fn getpwnam "const char *login"
  80 .Ft int
  81 .Fn getpwnam_r "const char *name" "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result"
  82 .Ft struct passwd *
  83 .Fn getpwuid "uid_t uid"
  84 .Ft int
  85 .Fn getpwuid_r "uid_t uid" "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result"
  86 .Ft struct passwd *
  87 .Fn getpwuuid "uuid_t uuid"
  88 .Ft int
  89 .Fn getpwuuid_r "uuid_t uuid" "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result"
  90 .Ft int
  91 .Fn setpassent "int stayopen"
  92 .Ft void
  93 .Fn setpwent void
  94 .Ft void
  95 .Fn endpwent void
  96 .Sh DESCRIPTION
  97 These functions
  98 .\"operate on the password database file
  99 obtain information from
 100 .Xr opendirectoryd 8 ,
 101 including records in
 102 .Pa /etc/master.passwd
 103 which is described
 104 in
 105 .Xr master.passwd 5 .
 106 Each entry in the database is defined by the structure
 107 .Vt passwd
 108 found in the include
 109 file
 110 .In pwd.h :
 111 .Bd -literal -offset indent
 112 struct passwd {
 113         char    *pw_name;       /* user name */
 114         char    *pw_passwd;     /* encrypted password */
 115         uid_t   pw_uid;         /* user uid */
 116         gid_t   pw_gid;         /* user gid */
 117         time_t  pw_change;      /* password change time */
 118         char    *pw_class;      /* user access class */
 119         char    *pw_gecos;      /* Honeywell login info */
 120         char    *pw_dir;        /* home directory */
 121         char    *pw_shell;      /* default shell */
 122         time_t  pw_expire;      /* account expiration */
 123         int     pw_fields;      /* internal: fields filled in */
 124 };
 125 .Ed
 126 .Pp
 127 The functions
 128 .Fn getpwnam ,
 129 .Fn getpwuid ,
 130 and
 131 .Fn getpwuuid
 132 search the password database for the given login name, user uid, or user uuid
 133 respectively, always returning the first one encountered.
 134 .Pp
 135 Note that the password file
 136 .Pa /etc/master.passwd
 137 does not contain user UUIDs.
 138 The UUID for a user may be found using
 139 .Fn mbr_uid_to_uuid .
 140 .Pp
 141 On OS X, these routines are thread-safe and return a pointer to a
 142 thread-specific data structure.  The contents of this data
 143 structure are automatically released by subsequent calls to
 144 any of these routines on the same thread, or when the thread exits.
 145 These routines are therefore unsuitable for use in libraries or frameworks,
 146 from where they may overwrite the per-thread data that the calling
 147 application expects to find as a result of its own calls to these
 148 routines. Library and framework code should use the alternative reentrant
 149 variants detailed below.
 150 .Pp
 151 The
 152 .Fn getpwent
 153 function
 154 searches all available directory services on it's first invocation.
 155 It caches the returned entries in a list
 156 and returns user account entries one at a time.
 157 .Pp
 158 .Em NOTE
 159 that
 160 .Fn getpwent
 161 may cause a very lengthy search for user account records by
 162 .Nm opendirectoryd
 163 and may result in a large number of user account records being cached
 164 by the calling process.
 165 Use of this function is not advised.
 166 .Pp
 167 The functions
 168 .Fn getpwnam_r ,
 169 .Fn getpwuid_r ,
 170 and
 171 .Fn getpwuuid_r
 172 are alternative versions of
 173 .Fn getpwnam ,
 174 .Fn getpwuid ,
 175 and
 176 .Fn getpwuuid
 177 respectively.
 178 They store the results of their search in the caller-provided
 179 .Fa pwd
 180 structure, which additionally contains pointers to strings that are
 181 stored in the caller-provided
 182 .Fa buffer
 183 of size
 184 .Fa bufsize .
 185 (The maximum required
 186 .Fa bufsize
 187 can be obtained by passing the _SC_GETPW_R_SIZE_MAX constant to the
 188 .Xr sysconf 3
 189 call. See example code below.) When these functions are successful, the
 190 .Fa pwd
 191 argument will be filled in, and a pointer to that argument will be
 192 stored in the caller-provided
 193 .Fa result .
 194 If an entry is not found or an error occurs,
 195 .Fa result
 196 will be set to
 197 .Dv NULL .
 198 .Pp
 199 The
 200 .Fn setpassent
 201 function causes
 202 .Fn getpwent
 203 to ``rewind'' to the beginning of the list of entries cached by a previous
 204 .Fn getpwent
 205 call.
 206 The cache is not cleared.
 207 The
 208 .Fa stayopen
 209 parameter value is unused on OS X.
 210 .Pp
 211 The
 212 .Fn setpwent
 213 and
 214 .Fn endpwent
 215 functions clear the cached results from a previous
 216 .Fn getpwent
 217 call.
 218 .Pp
 219 .\"These routines have been written to ``shadow'' the password file, e.g.\&
 220 .\"allow only certain programs to have access to the encrypted password.
 221 .\"If the process which calls them has an effective uid of 0, the encrypted
 222 .\"password will be returned, otherwise, the password field of the returned
 223 .\"structure will point to the string
 224 These routines have been written to
 225 .Ql shadow
 226 the password of user records created on Mac OS X 10.3 or later,
 227 by returning a structure whose password field points to the string
 228 .Ql ******** .
 229 Legacy crypt passwords are still returned for user records created on
 230 earlier versions of Mac OS X whose
 231 .Xr opendirectoryd 8
 232 .Dt AuthenticationAuthority
 233 attribute contains the value
 234 .Ql ;basic; .
 235 .Pp
 236 Note that
 237 .Xr opendirectoryd 8
 238 allows user records from some sources which may not include all the component
 239 fields present in a passwd structure.
 240 Only the name, uid, and gid of a user record are required.
 241 Default values will be supplied as follows:
 242 .Bd -literal -offset indent
 243 pw_passwd = "*"
 244 pw_change = 0
 245 pw_class = ""
 246 pw_gecos = ""
 247 pw_dir = "/var/empty"
 248 pw_shell = "/usr/bin/false"
 249 pw_expire = 0
 250 .Ed
 251 .Sh RETURN VALUES
 252 The functions
 253 .Fn getpwent ,
 254 .Fn getpwnam ,
 255 .Fn getpwuid ,
 256 and
 257 .Fn getpwuuid
 258 return a valid pointer to a passwd structure on success
 259 or
 260 .Dv NULL
 261 if the entry is not found or if an error occurs.
 262 If an error does occur,
 263 .Va errno
 264 will be set.
 265 Note that programs must explicitly set
 266 .Va errno
 267 to zero before calling any of these functions if they need to
 268 distinguish between a non-existent entry and an error.
 269 The functions
 270 .Fn getpwnam_r ,
 271 .Fn getpwuid_r ,
 272 and
 273 .Fn getpwuuid_r
 274 return 0 if no error occurred, or an error number to indicate failure.
 275 It is not an error if a matching entry is not found.
 276 (Thus, if
 277 .Fa result
 278 is
 279 .Dv NULL
 280 and the return value is 0, no matching entry exists.)
 281 .Pp
 282 The
 283 .Fn setpassent
 284 function returns 0 on failure and 1 on success.
 285 The
 286 .Fn endpwent
 287 and
 288 .Fn setpwent
 289 functions
 290 have no return value.
 291 .Sh EXAMPLES
 292 To print the current user's home directory without depending on per-thread storage:
 293 .Bd -literal -offset indent
 294 #include <sys/types.h>
 295 #include <unistd.h>
 296 #include <stdlib.h>
 297 #include <stdio.h>
 298 #include <pwd.h>
 299
 300 int bufsize;
 301
 302 if ((bufsize = sysconf(_SC_GETPW_R_SIZE_MAX)) == -1)
 303     abort();
 304
 305 char buffer[bufsize];
 306 struct passwd pwd, *result = NULL;
 307 if (getpwuid_r(getuid(), &pwd, buffer, bufsize, &result) != 0 || !result)
 308     abort();
 309
 310 printf("%s\\n", pwd.pw_dir);
 311 .Ed
 312 .Sh FILES
 313 .Bl -tag -width /etc/master.passwd -compact
 314 .\".It Pa /etc/pwd.db
 315 .\"The insecure password database file
 316 .\".It Pa /etc/spwd.db
 317 The secure password database file
 318 .It Pa /etc/master.passwd
 319 The current password file
 320 .It Pa /etc/passwd
 321 A Version 7 format password file
 322 .El
 323 .\".Sh COMPATIBILITY
 324 .\"The historic function
 325 .\".Xr setpwfile 3 ,
 326 .\"which allowed the specification of alternate password databases,
 327 .\"has been deprecated and is no longer available.
 328 .Sh ERRORS
 329 These routines may fail for any of the errors specified in
 330 .Xr open 2 ,
 331 .Xr dbopen 3 ,
 332 .Xr socket 2 ,
 333 and
 334 .Xr connect 2 ,
 335 in addition to the following:
 336 .Bl -tag -width Er
 337 .It Bq Er ERANGE
 338 The buffer specified by the
 339 .Fa buffer
 340 and
 341 .Fa bufsize
 342 arguments was insufficiently sized to store the result.
 343 The caller should retry with a larger buffer.
 344 .El
 345 .Sh SEE ALSO
 346 .Xr getlogin 2 ,
 347 .Xr getgrent 3 ,
 348 .\".Xr nsswitch.conf 5 ,
 349 .Xr passwd 5 ,
 350 .\".Xr pwd_mkdb 8 ,
 351 .\".Xr vipw 8 ,
 352 .Xr mbr_uid_to_uuid 3,
 353 .Xr opendirectoryd 8 ,
 354 .Xr yp 8
 355 .Sh STANDARDS
 356 The
 357 .Fn getpwent ,
 358 .Fn getpwnam ,
 359 .Fn getpwnam_r ,
 360 .Fn getpwuid ,
 361 .Fn getpwuid_r ,
 362 .Fn setpwent ,
 363 and
 364 .Fn endpwent
 365 functions conform to
 366 .St -p1003.1-96 .
 367 .Sh HISTORY
 368 The
 369 .Fn getpwent ,
 370 .Fn getpwnam ,
 371 .Fn getpwuid ,
 372 .Fn setpwent ,
 373 and
 374 .Fn endpwent
 375 functions appeared in
 376 .At v7 .
 377 The
 378 .Fn setpassent
 379 function appeared in
 380 .Bx 4.3 Reno .
 381 The
 382 .\".Fn getpwent_r ,
 383 .\".Fn getpwnam_r ,
 384 .Fn getpwnam_r
 385 and
 386 .Fn getpwuid_r
 387 functions appeared in
 388 .Fx 5.1 .
 389 The functions
 390 .Fn getpwuuid
 391 and
 392 .Fn getpwuuid_r
 393 appeared in Mac OS X 10.8.
 394 .Sh BUGS
 395 The functions
 396 .Fn getpwent ,
 397 .Fn getpwnam ,
 398 .Fn getpwuid ,
 399 and
 400 .Fn getpwuuid ,
 401 .\"leave their results in an internal static object and return
 402 leave their results in an internal thread-specific memory and return
 403 a pointer to that object.
 404 Subsequent calls to
 405 the same function
 406 will modify the same object.
 407 .\".Pp
 408 .\"The functions
 409 .\".Fn getpwent ,
 410 .\".Fn getpwent_r ,
 411 .\".Fn endpwent ,
 412 .\".Fn setpassent ,
 413 .\"and
 414 .\".Fn setpwent
 415 .\"are fairly useless in a networked environment and should be
 416 .\"avoided, if possible.
 417 .\"The
 418 .\".Fn getpwent
 419 .\"and
 420 .\".Fn getpwent_r
 421 .\"functions
 422 .\"make no attempt to suppress duplicate information if multiple
 423 .\"sources are specified in
 424 .\".Xr nsswitch.conf 5 .