1/* Common code for file-based database parsers in nss_files module.
2 Copyright (C) 1996-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <ctype.h>
20#include <errno.h>
21#include <string.h>
22#include <stdlib.h>
23#include <stdint.h>
24
25/* These symbols are defined by the including source file:
26
27 ENTNAME -- database name of the structure and functions (hostent, pwent).
28 STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
29 DATABASE -- string of the database file's name ("hosts", "passwd").
30
31 ENTDATA -- if defined, `struct ENTDATA' is used by the parser to store
32 things pointed to by the resultant `struct STRUCTURE'.
33
34 NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
35
36 EXTRA_ARGS -- defined iff extra parameters must be passed to the parser
37 EXTRA_ARGS_DECL -- declaration for these extra parameters
38 EXTRA_ARGS_VALUE -- values to be passed for these parameters
39
40 Also see files-XXX.c. */
41
42#ifndef EXTRA_ARGS
43# define EXTRA_ARGS
44# define EXTRA_ARGS_DECL
45# define EXTRA_ARGS_VALUE
46#endif
47
48#define CONCAT(a,b) CONCAT1(a,b)
49#define CONCAT1(a,b) a##b
50
51#ifndef STRUCTURE
52# define STRUCTURE ENTNAME
53#endif
54
55
56struct parser_data
57 {
58#ifdef ENTDATA
59 struct ENTDATA entdata;
60# define ENTDATA_DECL(data) struct ENTDATA *const entdata = &data->entdata;
61#else
62# define ENTDATA_DECL(data)
63#endif
64 char linebuffer[0];
65 };
66
67#ifdef ENTDATA
68/* The function can't be exported, because the entdata structure
69 is defined only in files-foo.c. */
70# define parser_stclass static
71# define nss_files_parse_hidden_def(name)
72#else
73/* Export the line parser function so it can be used in nss_db. */
74# define parser_stclass /* Global */
75# define parse_line CONCAT(_nss_files_parse_,ENTNAME)
76# if IS_IN (libc)
77/* We are defining one of the functions that actually lives in libc
78 because it is used to implement fget*ent and suchlike. */
79# define nss_files_parse_hidden_def(name) libc_hidden_def (name)
80# else
81# define nss_files_parse_hidden_def(name) libnss_files_hidden_def (name)
82# endif
83#endif
84
85
86#ifdef EXTERN_PARSER
87
88/* The parser is defined in a different module. */
89extern int parse_line (char *line, struct STRUCTURE *result,
90 struct parser_data *data, size_t datalen, int *errnop
91 EXTRA_ARGS_DECL);
92
93# define LINE_PARSER(EOLSET, BODY) /* Do nothing */
94
95#else
96
97/* Define a line parsing function. */
98
99# define LINE_PARSER(EOLSET, BODY) \
100parser_stclass int \
101parse_line (char *line, struct STRUCTURE *result, \
102 struct parser_data *data, size_t datalen, int *errnop \
103 EXTRA_ARGS_DECL) \
104{ \
105 ENTDATA_DECL (data) \
106 BUFFER_PREPARE \
107 char *p = strpbrk (line, EOLSET "\n"); \
108 if (p != NULL) \
109 *p = '\0'; \
110 BODY; \
111 TRAILING_LIST_PARSER; \
112 return 1; \
113} \
114nss_files_parse_hidden_def (parse_line)
115
116
117# define STRING_FIELD(variable, terminator_p, swallow) \
118 { \
119 variable = line; \
120 while (*line != '\0' && !terminator_p (*line)) \
121 ++line; \
122 if (*line != '\0') \
123 { \
124 *line = '\0'; \
125 do \
126 ++line; \
127 while (swallow && terminator_p (*line)); \
128 } \
129 }
130
131# define STRING_LIST(variable, terminator_c) \
132 { \
133 char **list = parse_list (&line, buf_start, buf_end, terminator_c, \
134 errnop); \
135 if (list) \
136 variable = list; \
137 else \
138 return -1; /* -1 indicates we ran out of space. */ \
139 \
140 /* Determine the new end of the buffer. */ \
141 while (*list != NULL) \
142 ++list; \
143 buf_start = (char *) (list + 1); \
144 }
145
146/* Helper function. */
147static inline uint32_t
148__attribute__ ((always_inline))
149strtou32 (const char *nptr, char **endptr, int base)
150{
151 unsigned long int val = strtoul (nptr, endptr, base);
152
153 /* Match the 32-bit behavior on 64-bit platforms. */
154 if (sizeof (long int) > 4 && val > 0xffffffff)
155 val = 0xffffffff;
156
157 return val;
158}
159
160# define INT_FIELD(variable, terminator_p, swallow, base, convert) \
161 { \
162 char *endp; \
163 variable = convert (strtou32 (line, &endp, base)); \
164 if (endp == line) \
165 return 0; \
166 else if (terminator_p (*endp)) \
167 do \
168 ++endp; \
169 while (swallow && terminator_p (*endp)); \
170 else if (*endp != '\0') \
171 return 0; \
172 line = endp; \
173 }
174
175# define INT_FIELD_MAYBE_NULL(variable, terminator_p, swallow, base, convert, default) \
176 { \
177 char *endp; \
178 if (*line == '\0') \
179 /* We expect some more input, so don't allow the string to end here. */ \
180 return 0; \
181 variable = convert (strtou32 (line, &endp, base)); \
182 if (endp == line) \
183 variable = default; \
184 if (terminator_p (*endp)) \
185 do \
186 ++endp; \
187 while (swallow && terminator_p (*endp)); \
188 else if (*endp != '\0') \
189 return 0; \
190 line = endp; \
191 }
192
193# define ISCOLON(c) ((c) == ':')
194
195
196# ifndef TRAILING_LIST_MEMBER
197# define BUFFER_PREPARE /* Nothing to do. */
198# define TRAILING_LIST_PARSER /* Nothing to do. */
199# else
200
201# define BUFFER_PREPARE \
202 char *buf_start = NULL; \
203 char *buf_end = (char *) data + datalen; \
204 if (line >= data->linebuffer && line < buf_end) \
205 /* Find the end of the line buffer, we will use the space in \
206 DATA after it for storing the vector of pointers. */ \
207 buf_start = strchr (line, '\0') + 1; \
208 else \
209 /* LINE does not point within DATA->linebuffer, so that space is \
210 not being used for scratch space right now. We can use all of \
211 it for the pointer vector storage. */ \
212 buf_start = data->linebuffer; \
213
214# define TRAILING_LIST_PARSER \
215{ \
216 if (buf_start == NULL) \
217 { \
218 if (line >= data->linebuffer && line < buf_end) \
219 /* Find the end of the line buffer, we will use the space in \
220 DATA after it for storing the vector of pointers. */ \
221 buf_start = strchr (line, '\0') + 1; \
222 else \
223 /* LINE does not point within DATA->linebuffer, so that space is \
224 not being used for scratch space right now. We can use all of \
225 it for the pointer vector storage. */ \
226 buf_start = data->linebuffer; \
227 } \
228 \
229 char **list = parse_list (&line, buf_start, buf_end, '\0', errnop); \
230 if (list) \
231 result->TRAILING_LIST_MEMBER = list; \
232 else \
233 return -1; /* -1 indicates we ran out of space. */ \
234}
235
236static inline char **
237__attribute ((always_inline))
238parse_list (char **linep, char *eol, char *buf_end, int terminator_c,
239 int *errnop)
240{
241 char *line = *linep;
242 char **list, **p;
243
244 /* Adjust the pointer so it is aligned for storing pointers. */
245 eol += __alignof__ (char *) - 1;
246 eol -= (eol - (char *) 0) % __alignof__ (char *);
247 /* We will start the storage here for the vector of pointers. */
248 list = (char **) eol;
249
250 p = list;
251 while (1)
252 {
253 if ((char *) (p + 2) > buf_end)
254 {
255 /* We cannot fit another pointer in the buffer. */
256 *errnop = ERANGE;
257 return NULL;
258 }
259
260 if (*line == '\0')
261 break;
262 if (*line == terminator_c)
263 {
264 ++line;
265 break;
266 }
267
268 /* Skip leading white space. This might not be portable but useful. */
269 while (isspace (*line))
270 ++line;
271
272 char *elt = line;
273 while (1)
274 {
275 if (*line == '\0' || *line == terminator_c
276 || TRAILING_LIST_SEPARATOR_P (*line))
277 {
278 /* End of the next entry. */
279 if (line > elt)
280 /* We really found some data. */
281 *p++ = elt;
282
283 /* Terminate string if necessary. */
284 if (*line != '\0')
285 {
286 char endc = *line;
287 *line++ = '\0';
288 if (endc == terminator_c)
289 goto out;
290 }
291 break;
292 }
293 ++line;
294 }
295 }
296 out:
297 *p = NULL;
298 *linep = line;
299
300 return list;
301}
302
303# endif /* TRAILING_LIST_MEMBER */
304#endif /* EXTERN_PARSER */
305
306
307#define LOOKUP_NAME(nameelt, aliaselt) \
308{ \
309 char **ap; \
310 if (! strcmp (name, result->nameelt)) \
311 break; \
312 for (ap = result->aliaselt; *ap; ++ap) \
313 if (! strcmp (name, *ap)) \
314 break; \
315 if (*ap) \
316 break; \
317}
318
319#define LOOKUP_NAME_CASE(nameelt, aliaselt) \
320{ \
321 char **ap; \
322 if (! __strcasecmp (name, result->nameelt)) \
323 break; \
324 for (ap = result->aliaselt; *ap; ++ap) \
325 if (! __strcasecmp (name, *ap)) \
326 break; \
327 if (*ap) \
328 break; \
329}
330
331
332/* This is defined by db-*.c to include "../nss_db/db-XXX.c" instead. */
333#ifndef GENERIC
334# define GENERIC "files-XXX.c"
335#endif
336