man3/getpw.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .\" References consulted:
   6 .\"     Linux libc source code
   7 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
   8 .\"     386BSD man pages
   9 .\" Modified Sat Jul 24 19:23:25 1993 by Rik Faith (faith@cs.unc.edu)
  10 .\" Modified Mon May 27 21:37:47 1996 by Martin Schulze (joey@linux.de)
  11 .\"
  12 .TH getpw 3 (date) "Linux man-pages (unreleased)"
  13 .SH NAME
  14 getpw \- reconstruct password line entry
  15 .SH LIBRARY
  16 Standard C library
  17 .RI ( libc ", " \-lc )
  18 .SH SYNOPSIS
  19 .nf
  20 .BR "#define _GNU_SOURCE" "             /* See feature_test_macros(7) */"
  21 .B #include <sys/types.h>
  22 .B #include <pwd.h>
  23 .PP
  24 .BI "[[deprecated]] int getpw(uid_t " uid ", char *" buf );
  25 .fi
  26 .SH DESCRIPTION
  27 The
  28 .BR getpw ()
  29 function reconstructs the password line entry for
  30 the given user ID \fIuid\fP in the buffer \fIbuf\fP.
  31 The returned buffer contains a line of format
  32 .PP
  33 .in +4n
  34 .EX
  35 .B name:passwd:uid:gid:gecos:dir:shell
  36 .EE
  37 .in
  38 .PP
  39 The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:
  40 .PP
  41 .in +4n
  42 .EX
  43 struct passwd {
  44     char   *pw_name;       /* username */
  45     char   *pw_passwd;     /* user password */
  46     uid_t   pw_uid;        /* user ID */
  47     gid_t   pw_gid;        /* group ID */
  48     char   *pw_gecos;      /* user information */
  49     char   *pw_dir;        /* home directory */
  50     char   *pw_shell;      /* shell program */
  51 };
  52 .EE
  53 .in
  54 .PP
  55 For more information about the fields of this structure, see
  56 .BR passwd (5).
  57 .SH RETURN VALUE
  58 The
  59 .BR getpw ()
  60 function returns 0 on success; on error, it returns \-1, and
  61 .I errno
  62 is set to indicate the error.
  63 .PP
  64 If
  65 .I uid
  66 is not found in the password database,
  67 .BR getpw ()
  68 returns \-1, sets
  69 .I errno
  70 to 0, and leaves
  71 .I buf
  72 unchanged.
  73 .SH ERRORS
  74 .TP
  75 .BR 0 " or " ENOENT
  76 No user corresponding to
  77 .IR uid .
  78 .TP
  79 .B EINVAL
  80 .I buf
  81 is NULL.
  82 .TP
  83 .B ENOMEM
  84 Insufficient memory to allocate
  85 .I passwd
  86 structure.
  87 .SH FILES
  88 .TP
  89 .I /etc/passwd
  90 password database file
  91 .SH ATTRIBUTES
  92 For an explanation of the terms used in this section, see
  93 .BR attributes (7).
  94 .ad l
  95 .nh
  96 .TS
  97 allbox;
  98 lbx lb lb
  99 l l l.
 100 Interface       Attribute       Value
 101 T{
 102 .BR getpw ()
 103 T}      Thread safety   MT-Safe locale
 104 .TE
 105 .hy
 106 .ad
 107 .sp 1
 108 .SH STANDARDS
 109 SVr2.
 110 .SH BUGS
 111 The
 112 .BR getpw ()
 113 function is dangerous as it may overflow the provided buffer
 114 .IR buf .
 115 It is obsoleted by
 116 .BR getpwuid (3).
 117 .SH SEE ALSO
 118 .BR endpwent (3),
 119 .BR fgetpwent (3),
 120 .BR getpwent (3),
 121 .BR getpwnam (3),
 122 .BR getpwuid (3),
 123 .BR putpwent (3),
 124 .BR setpwent (3),
 125 .BR passwd (5)