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From: @(#)getpwent.3 8.2 (Berkeley) 12/11/93
$FreeBSD: releng/10.2/lib/libc/gen/getpwent.3 165903 2007-01-09 00:28:16Z imp $
.Dd April 16, 2003 .Dt GETPWENT 3 .Os .Sh NAME .Nm getpwent , .Nm getpwent_r , .Nm getpwnam , .Nm getpwnam_r , .Nm getpwuid , .Nm getpwuid_r , .Nm setpassent , .Nm setpwent , .Nm endpwent .Nd password database operations .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/types.h n pwd.h .Ft struct passwd * .Fn getpwent void .Ft int .Fn getpwent_r "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result" .Ft struct passwd * .Fn getpwnam "const char *login" .Ft int .Fn getpwnam_r "const char *name" "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result" .Ft struct passwd * .Fn getpwuid "uid_t uid" .Ft int .Fn getpwuid_r "uid_t uid" "struct passwd *pwd" "char *buffer" "size_t bufsize" "struct passwd **result" .Ft int .Fn setpassent "int stayopen" .Ft void .Fn setpwent void .Ft void .Fn endpwent void .Sh DESCRIPTION These functions operate on the password database file which is described in .Xr passwd 5 . Each entry in the database is defined by the structure .Vt passwd found in the include file n pwd.h : d -literal -offset indent 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 */ }; .Ed
p The functions .Fn getpwnam and .Fn getpwuid search the password database for the given login name or user uid, respectively, always returning the first one encountered.
p The .Fn getpwent function sequentially reads the password database and is intended for programs that wish to process the complete list of users.
p The functions .Fn getpwent_r , .Fn getpwnam_r , and .Fn getpwuid_r are thread-safe versions of .Fn getpwent , .Fn getpwnam , and .Fn getpwuid , respectively. The caller must provide storage for the results of the search in the .Fa pwd , .Fa buffer , .Fa bufsize , and .Fa result arguments. When these functions are successful, the .Fa pwd argument will be filled-in, and a pointer to that argument will be stored in .Fa result . If an entry is not found or an error occurs, .Fa result will be set to .Dv NULL .
p The .Fn setpassent function accomplishes two purposes. First, it causes .Fn getpwent to ``rewind'' to the beginning of the database. Additionally, if .Fa 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 .Fn getpwent as it does not close its file descriptors by default.)
p 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.
p The .Fn setpwent function is identical to .Fn setpassent with an argument of zero.
p The .Fn endpwent function closes any open files.
p 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 .Ql * . .Sh RETURN VALUES The functions .Fn getpwent , .Fn getpwnam , and .Fn getpwuid return a valid pointer to a passwd structure on success or .Dv NULL if the entry is not found or if an error occurs. If an error does occur, .Va errno will be set. Note that programs must explicitly set .Va errno to zero before calling any of these functions if they need to distinguish between a non-existent entry and an error. The functions .Fn getpwent_r , .Fn getpwnam_r , and .Fn getpwuid_r return 0 if no error occurred, or an error number to indicate failure. It is not an error if a matching entry is not found. (Thus, if .Fa result is .Dv NULL and the return value is 0, no matching entry exists.)
p The .Fn setpassent function returns 0 on failure and 1 on success. The .Fn endpwent and .Fn setpwent functions have no return value. .Sh FILES l -tag -width /etc/master.passwd -compact t Pa /etc/pwd.db The insecure password database file t Pa /etc/spwd.db The secure password database file t Pa /etc/master.passwd The current password file t Pa /etc/passwd A Version 7 format password file .El .Sh COMPATIBILITY The historic function .Xr setpwfile 3 , which allowed the specification of alternate password databases, has been deprecated and is no longer available. .Sh ERRORS These routines may fail for any of the errors specified in .Xr open 2 , .Xr dbopen 3 , .Xr socket 2 , and .Xr connect 2 , in addition to the following: l -tag -width Er t Bq Er ERANGE The buffer specified by the .Fa buffer and .Fa bufsize arguments was insufficiently sized to store the result. The caller should retry with a larger buffer. .El .Sh SEE ALSO .Xr getlogin 2 , .Xr getgrent 3 , .Xr nsswitch.conf 5 , .Xr passwd 5 , .Xr pwd_mkdb 8 , .Xr vipw 8 , .Xr yp 8 .Sh STANDARDS The .Fn getpwent , .Fn getpwnam , .Fn getpwnam_r , .Fn getpwuid , .Fn getpwuid_r , .Fn setpwent , and .Fn endpwent functions conform to .St -p1003.1-96 . .Sh HISTORY The .Fn getpwent , .Fn getpwnam , .Fn getpwuid , .Fn setpwent , and .Fn endpwent functions appeared in .At v7 . The .Fn setpassent function appeared in x 4.3 Reno . The .Fn getpwent_r , .Fn getpwnam_r , and .Fn getpwuid_r functions appeared in .Fx 5.1 . .Sh BUGS The functions .Fn getpwent , .Fn getpwnam , and .Fn getpwuid , leave their results in an internal static object and return a pointer to that object. Subsequent calls to the same function will modify the same object.
p The functions .Fn getpwent , .Fn getpwent_r , .Fn endpwent , .Fn setpassent , and .Fn setpwent are fairly useless in a networked environment and should be avoided, if possible. The .Fn getpwent and .Fn getpwent_r functions make no attempt to suppress duplicate information if multiple sources are specified in .Xr nsswitch.conf 5 .