man-pages/man3/getpw.3.html
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<H1>GETPW</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
getpw - reconstruct password line entry
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#define _GNU_SOURCE</B> /* See <A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A>(7) */
<B>#include &lt;<A HREF="file:///usr/include/sys/types.h">sys/types.h</A>&gt;</B>
<B>#include &lt;<A HREF="file:///usr/include/pwd.h">pwd.h</A>&gt;</B>
<B>int getpw(uid_t </B><I>uid</I><B>, char *</B><I>buf</I><B>);</B>
</PRE>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
The
<B>getpw</B>()
function reconstructs the password line entry for
the given user ID <I>uid</I> in the buffer <I>buf</I>.
The returned buffer contains a line of format
<P>
<B>name:passwd:uid:gid:gecos:dir:shell</B>
<P>
The <I>passwd</I> structure is defined in <I>&lt;<A HREF="file:///usr/include/pwd.h">pwd.h</A>&gt;</I> as follows:
<P>
struct passwd {
<BR>&nbsp;&nbsp;&nbsp;&nbsp;char&nbsp;&nbsp;&nbsp;*pw_name;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;username&nbsp;*/
<BR>&nbsp;&nbsp;&nbsp;&nbsp;char&nbsp;&nbsp;&nbsp;*pw_passwd;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;user&nbsp;password&nbsp;*/
<BR>&nbsp;&nbsp;&nbsp;&nbsp;uid_t&nbsp;&nbsp;&nbsp;pw_uid;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;user&nbsp;ID&nbsp;*/
<BR>&nbsp;&nbsp;&nbsp;&nbsp;gid_t&nbsp;&nbsp;&nbsp;pw_gid;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;group&nbsp;ID&nbsp;*/
<BR>&nbsp;&nbsp;&nbsp;&nbsp;char&nbsp;&nbsp;&nbsp;*pw_gecos;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;user&nbsp;information&nbsp;*/
<BR>&nbsp;&nbsp;&nbsp;&nbsp;char&nbsp;&nbsp;&nbsp;*pw_dir;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;home&nbsp;directory&nbsp;*/
<BR>&nbsp;&nbsp;&nbsp;&nbsp;char&nbsp;&nbsp;&nbsp;*pw_shell;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;shell&nbsp;program&nbsp;*/
};
<P>
For more information about the fields of this structure, see
<B><A HREF="/cgi-bin/man/man2html?5+passwd">passwd</A></B>(5).
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
The
<B>getpw</B>()
function returns 0 on success; on error, it returns -1, and
<I>errno</I>
is set to indicate the error.
<P>
If
<I>uid</I>
is not found in the password database,
<B>getpw</B>()
returns -1, sets
<I>errno</I>
to 0, and leaves
<I>buf</I>
unchanged.
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
<DL COMPACT>
<DT id="1"><B>0</B> or <B>ENOENT</B>
<DD>
No user corresponding to
<I>uid</I>.
<DT id="2"><B>EINVAL</B>
<DD>
<I>buf</I>
is NULL.
<DT id="3"><B>ENOMEM</B>
<DD>
Insufficient memory to allocate
<I>passwd</I>
structure.
</DL>
<A NAME="lbAG">&nbsp;</A>
<H2>FILES</H2>
<DL COMPACT>
<DT id="4"><I>/etc/passwd</I>
<DD>
password database file
</DL>
<A NAME="lbAH">&nbsp;</A>
<H2>ATTRIBUTES</H2>
For an explanation of the terms used in this section, see
<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
<TABLE BORDER>
<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
<TR VALIGN=top><TD>
<B>getpw</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe locale<BR></TD></TR>
</TABLE>
<P>
<A NAME="lbAI">&nbsp;</A>
<H2>CONFORMING TO</H2>
SVr2.
<A NAME="lbAJ">&nbsp;</A>
<H2>BUGS</H2>
The
<B>getpw</B>()
function is dangerous as it may overflow the provided buffer
<I>buf</I>.
It is obsoleted by
<B><A HREF="/cgi-bin/man/man2html?3+getpwuid">getpwuid</A></B>(3).
<A NAME="lbAK">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?3+endpwent">endpwent</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+fgetpwent">fgetpwent</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+getpwent">getpwent</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+getpwnam">getpwnam</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+getpwuid">getpwuid</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+putpwent">putpwent</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+setpwent">setpwent</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?5+passwd">passwd</A></B>(5)
<A NAME="lbAL">&nbsp;</A>
<H2>COLOPHON</H2>
This page is part of release 5.05 of the Linux
<I>man-pages</I>
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="5"><A HREF="#lbAB">NAME</A><DD>
<DT id="6"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="7"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="8"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="9"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="10"><A HREF="#lbAG">FILES</A><DD>
<DT id="11"><A HREF="#lbAH">ATTRIBUTES</A><DD>
<DT id="12"><A HREF="#lbAI">CONFORMING TO</A><DD>
<DT id="13"><A HREF="#lbAJ">BUGS</A><DD>
<DT id="14"><A HREF="#lbAK">SEE ALSO</A><DD>
<DT id="15"><A HREF="#lbAL">COLOPHON</A><DD>
</DL>
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Time: 00:05:44 GMT, March 31, 2021
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