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71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/* unlinkdir.c - determine (and maybe change) whether we can unlink directories
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Copyright (C) 2005 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* Written by Paul Eggert and Jim Meyering. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include "unlinkdir.h"
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#if HAVE_PRIV_H
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# include <priv.h>
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#endif
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#include <unistd.h>
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#if ! UNLINK_CANNOT_UNLINK_DIR
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/* Return true if we cannot unlink directories, false if we might be
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able to unlink directories. If possible, tell the kernel we don't
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want to be able to unlink directories, so that we can return true. */
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bool
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cannot_unlink_dir (void)
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{
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static bool initialized;
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static bool cannot;
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if (! initialized)
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{
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# if defined PRIV_EFFECTIVE && defined PRIV_SYS_LINKDIR
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/* We might be able to unlink directories if we cannot
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determine our privileges, or if we have the
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PRIV_SYS_LINKDIR privilege and cannot delete it. */
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priv_set_t *pset = priv_allocset ();
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if (pset)
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{
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cannot =
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(getppriv (PRIV_EFFECTIVE, pset) == 0
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&& (! priv_ismember (pset, PRIV_SYS_LINKDIR)
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|| (priv_delset (pset, PRIV_SYS_LINKDIR) == 0
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&& setppriv (PRIV_SET, PRIV_EFFECTIVE, pset) == 0)));
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priv_freeset (pset);
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}
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# else
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/* In traditional Unix, only root can unlink directories. */
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cannot = (geteuid () != 0);
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# endif
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initialized = true;
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}
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return cannot;
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}
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#endif
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