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/* Parse a service line from nsswitch.conf.
Copyright (c) 1996-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <nsswitch.h>
#include <ctype.h>
#include <string.h>
#include <stdbool.h>
/* Staging area during parsing. */
#define DYNARRAY_STRUCT action_list
#define DYNARRAY_ELEMENT struct nss_action
#define DYNARRAY_PREFIX action_list_
#include <malloc/dynarray-skeleton.c>
/* Skip whitespace in line[]. */
#define SKIP_WS() \
while (line[0] != '\0' && isspace (line[0])) \
++line;
/* Read the source names:
`( <source> ( "[" "!"? (<status> "=" <action> )+ "]" )? )*'
*/
static bool
nss_action_parse (const char *line, struct action_list *result)
{
while (1)
{
SKIP_WS ();
if (line[0] == '\0')
/* No more sources specified. */
return true;
/* Read <source> identifier. */
const char *name = line;
while (line[0] != '\0' && !isspace (line[0]) && line[0] != '[')
++line;
if (name == line)
return true;
struct nss_action new_service
= { .module = __nss_module_allocate (name, line - name), };
if (new_service.module == NULL)
{
/* Memory allocation error. */
action_list_mark_failed (result);
return false;
}
nss_action_set_all (&new_service, NSS_ACTION_CONTINUE);
nss_action_set (&new_service, NSS_STATUS_SUCCESS, NSS_ACTION_RETURN);
nss_action_set (&new_service, NSS_STATUS_RETURN, NSS_ACTION_RETURN);
SKIP_WS ();
if (line[0] == '[')
{
/* Read criterions. */
/* Skip the '['. */
++line;
SKIP_WS ();
do
{
int not;
enum nss_status status;
lookup_actions action;
/* Grok ! before name to mean all statuses but that one. */
not = line[0] == '!';
if (not)
++line;
/* Read status name. */
name = line;
while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
&& line[0] != ']')
++line;
/* Compare with known statuses. */
if (line - name == 7)
{
if (__strncasecmp (name, "SUCCESS", 7) == 0)
status = NSS_STATUS_SUCCESS;
else if (__strncasecmp (name, "UNAVAIL", 7) == 0)
status = NSS_STATUS_UNAVAIL;
else
return false;
}
else if (line - name == 8)
{
if (__strncasecmp (name, "NOTFOUND", 8) == 0)
status = NSS_STATUS_NOTFOUND;
else if (__strncasecmp (name, "TRYAGAIN", 8) == 0)
status = NSS_STATUS_TRYAGAIN;
else
return false;
}
else
return false;
SKIP_WS ();
if (line[0] != '=')
return false;
/* Skip the '='. */
++line;
SKIP_WS ();
name = line;
while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
&& line[0] != ']')
++line;
if (line - name == 6 && __strncasecmp (name, "RETURN", 6) == 0)
action = NSS_ACTION_RETURN;
else if (line - name == 8
&& __strncasecmp (name, "CONTINUE", 8) == 0)
action = NSS_ACTION_CONTINUE;
else if (line - name == 5
&& __strncasecmp (name, "MERGE", 5) == 0)
action = NSS_ACTION_MERGE;
else
return false;
if (not)
{
/* Save the current action setting for this status,
set them all to the given action, and reset this one. */
const lookup_actions save
= nss_action_get (&new_service, status);
nss_action_set_all (&new_service, action);
nss_action_set (&new_service, status, save);
}
else
nss_action_set (&new_service, status, action);
SKIP_WS ();
}
while (line[0] != ']');
/* Skip the ']'. */
++line;
}
action_list_add (result, new_service);
}
}
nss_action_list
__nss_action_parse (const char *line)
{
struct action_list list;
action_list_init (&list);
if (nss_action_parse (line, &list))
{
size_t size;
struct nss_action null_service
= { .module = NULL, };
action_list_add (&list, null_service);
size = action_list_size (&list);
return __nss_action_allocate (action_list_begin (&list), size);
}
else if (action_list_has_failed (&list))
{
/* Memory allocation error. */
__set_errno (ENOMEM);
return NULL;
}
else
{
/* Parse error. */
__set_errno (EINVAL);
return NULL;
}
}
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