191 lines
4.9 KiB
HTML
191 lines
4.9 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of EUIDACCESS</TITLE>
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</HEAD><BODY>
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<H1>EUIDACCESS</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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euidaccess, eaccess - check effective user's permissions for a file
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<PRE>
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<B>#define _GNU_SOURCE</B> /* See <A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A>(7) */
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<B>#include <<A HREF="file:///usr/include/unistd.h">unistd.h</A>></B>
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<B>int euidaccess(const char *</B><I>pathname</I><B>, int </B><I>mode</I><B>);</B>
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<B>int eaccess(const char *</B><I>pathname</I><B>, int </B><I>mode</I><B>);</B>
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</PRE>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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Like
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<B><A HREF="/cgi-bin/man/man2html?2+access">access</A></B>(2),
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<B>euidaccess</B>()
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checks permissions and existence of the file identified by its argument
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<I>pathname</I>.
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However, whereas
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<B><A HREF="/cgi-bin/man/man2html?2+access">access</A></B>(2)
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performs checks using the real user and group identifiers of the process,
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<B>euidaccess</B>()
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uses the effective identifiers.
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<P>
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<I>mode</I>
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is a mask consisting of one or more of
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<B>R_OK</B>, <B>W_OK</B>, <B>X_OK</B>, and <B>F_OK</B>,
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with the same meanings as for
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<B><A HREF="/cgi-bin/man/man2html?2+access">access</A></B>(2).
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<P>
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<B>eaccess</B>()
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is a synonym for
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<B>euidaccess</B>(),
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provided for compatibility with some other systems.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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On success (all requested permissions granted), zero is returned.
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On error (at least one bit in
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<I>mode</I>
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asked for a permission that is denied, or some other error occurred),
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-1 is returned, and
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<I>errno</I>
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is set appropriately.
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<A NAME="lbAF"> </A>
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<H2>ERRORS</H2>
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As for
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<B><A HREF="/cgi-bin/man/man2html?2+access">access</A></B>(2).
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<A NAME="lbAG"> </A>
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<H2>VERSIONS</H2>
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The
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<B>eaccess</B>()
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function was added to glibc in version 2.4.
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<A NAME="lbAH"> </A>
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<H2>ATTRIBUTES</H2>
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For an explanation of the terms used in this section, see
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<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
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<TABLE BORDER>
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<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>euidaccess</B>(),
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<B>eaccess</B>()
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</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
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</TABLE>
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<A NAME="lbAI"> </A>
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<H2>CONFORMING TO</H2>
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These functions are nonstandard.
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Some other systems have an
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<B>eaccess</B>()
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function.
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<A NAME="lbAJ"> </A>
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<H2>NOTES</H2>
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<I>Warning</I>:
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Using this function to check a process's permissions on a file before
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performing some operation based on that information leads to race conditions:
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the file permissions may change between the two steps.
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Generally, it is safer just to attempt the desired operation and handle
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any permission error that occurs.
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<P>
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This function always dereferences symbolic links.
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If you need to check the permissions on a symbolic link, use
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<B><A HREF="/cgi-bin/man/man2html?2+faccessat">faccessat</A></B>(2)
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with the flags
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<B>AT_EACCESS</B>
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and
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<B>AT_SYMLINK_NOFOLLOW</B>.
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<A NAME="lbAK"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?2+access">access</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+chmod">chmod</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+chown">chown</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+faccessat">faccessat</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+open">open</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+setgid">setgid</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+setuid">setuid</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+stat">stat</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?7+credentials">credentials</A></B>(7),
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<B><A HREF="/cgi-bin/man/man2html?7+path_resolution">path_resolution</A></B>(7)
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<A NAME="lbAL"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="1"><A HREF="#lbAB">NAME</A><DD>
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<DT id="2"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="3"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="4"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="5"><A HREF="#lbAF">ERRORS</A><DD>
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<DT id="6"><A HREF="#lbAG">VERSIONS</A><DD>
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<DT id="7"><A HREF="#lbAH">ATTRIBUTES</A><DD>
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<DT id="8"><A HREF="#lbAI">CONFORMING TO</A><DD>
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<DT id="9"><A HREF="#lbAJ">NOTES</A><DD>
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<DT id="10"><A HREF="#lbAK">SEE ALSO</A><DD>
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<DT id="11"><A HREF="#lbAL">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:39 GMT, March 31, 2021
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</BODY>
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</HTML>
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