109 lines
3.6 KiB
C
109 lines
3.6 KiB
C
/* NSS actions, elements in a nsswitch.conf configuration line.
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Copyright (c) 2020-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _NSS_ACTION_H
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#define _NSS_ACTION_H
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#include <stddef.h>
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/* See nss_database.h for a summary of how this relates. */
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#include "nsswitch.h" /* For lookup_actions. */
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struct nss_module;
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/* A NSS action pairs a service module with the action for each result
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state. */
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struct nss_action
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{
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/* The service module that provides the functionality (potentially
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not yet loaded). */
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struct nss_module *module;
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/* Action according to result. Two bits for each lookup_actions
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value (from nsswitch.h), indexed by enum nss_status (from nss.h). */
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unsigned int action_bits;
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};
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/* Value to add to first nss_status value to get zero. */
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#define NSS_STATUS_BIAS 2
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/* Number of bits per lookup action. */
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#define NSS_BPL 2
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#define NSS_BPL_MASK ((1 << NSS_BPL) - 1)
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/* Index in actions of an NSS status. Note that in nss/nss.h the
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status starts at -2, and we shift that up to zero by adding 2.
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Thus for example NSS_STATUS_TRYAGAIN, which is -2, would index into
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the 0th bit place as expected. */
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static inline int
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nss_actions_bits_index (enum nss_status status)
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{
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return NSS_BPL * (NSS_STATUS_BIAS + status);
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}
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/* Returns the lookup_action value for STATUS in ACTION. */
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static inline lookup_actions
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nss_action_get (const struct nss_action *action, enum nss_status status)
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{
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return ((action->action_bits >> nss_actions_bits_index (status))
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& NSS_BPL_MASK);
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}
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/* Sets the lookup_action value for STATUS in ACTION. */
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static inline void
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nss_action_set (struct nss_action *action,
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enum nss_status status, lookup_actions actions)
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{
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int offset = nss_actions_bits_index (status);
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unsigned int mask = NSS_BPL_MASK << offset;
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action->action_bits = ((action->action_bits & ~mask)
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| ((unsigned int) actions << offset));
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}
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static inline void
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nss_action_set_all (struct nss_action *action, lookup_actions actions)
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{
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unsigned int bits = actions & NSS_BPL_MASK;
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action->action_bits = ( bits
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| (bits << (NSS_BPL * 1))
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| (bits << (NSS_BPL * 2))
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| (bits << (NSS_BPL * 3))
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| (bits << (NSS_BPL * 4))
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);
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}
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/* A list of struct nss_action objects in array terminated by an
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action with a NULL module. */
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typedef struct nss_action *nss_action_list;
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/* Returns a pointer to an allocated NSS action list that has COUNT
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actions that matches the array at ACTIONS. */
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nss_action_list __nss_action_allocate (struct nss_action *actions,
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size_t count) attribute_hidden;
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/* Returns a pointer to a list allocated by __nss_action_allocate, or
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NULL on error. ENOMEM means a (temporary) memory allocation error,
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EINVAL means that LINE is syntactically invalid. */
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nss_action_list __nss_action_parse (const char *line);
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/* Called from __libc_freeres. */
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void __nss_action_freeres (void) attribute_hidden;
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#endif /* _NSS_ACTION_H */
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