summaryrefslogtreecommitdiff
path: root/src/libbasic/extract-word.c
blob: ee35d2a0ec9e177ce611fc0b05d7e32f60309033 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd 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.

  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>

#include "alloc-util.h"
#include "escape.h"
#include "extract-word.h"
#include "log.h"
#include "macro.h"
#include "string-util.h"
#include "utf8.h"

int extract_first_word(const char **p, char **ret, const char *separators, ExtractFlags flags) {
        _cleanup_free_ char *s = NULL;
        size_t allocated = 0, sz = 0;
        char c;
        int r;

        char quote = 0;                 /* 0 or ' or " */
        bool backslash = false;         /* whether we've just seen a backslash */

        assert(p);
        assert(ret);

        /* Bail early if called after last value or with no input */
        if (!*p)
                goto finish_force_terminate;
        c = **p;

        if (!separators)
                separators = WHITESPACE;

        /* Parses the first word of a string, and returns it in
         * *ret. Removes all quotes in the process. When parsing fails
         * (because of an uneven number of quotes or similar), leaves
         * the pointer *p at the first invalid character. */

        if (flags & EXTRACT_DONT_COALESCE_SEPARATORS)
                if (!GREEDY_REALLOC(s, allocated, sz+1))
                        return -ENOMEM;

        for (;; (*p) ++, c = **p) {
                if (c == 0)
                        goto finish_force_terminate;
                else if (strchr(separators, c)) {
                        if (flags & EXTRACT_DONT_COALESCE_SEPARATORS) {
                                (*p) ++;
                                goto finish_force_next;
                        }
                } else {
                        /* We found a non-blank character, so we will always
                         * want to return a string (even if it is empty),
                         * allocate it here. */
                        if (!GREEDY_REALLOC(s, allocated, sz+1))
                                return -ENOMEM;
                        break;
                }
        }

        for (;; (*p) ++, c = **p) {
                if (backslash) {
                        if (!GREEDY_REALLOC(s, allocated, sz+7))
                                return -ENOMEM;

                        if (c == 0) {
                                if ((flags & EXTRACT_CUNESCAPE_RELAX) &&
                                    (!quote || flags & EXTRACT_RELAX)) {
                                        /* If we find an unquoted trailing backslash and we're in
                                         * EXTRACT_CUNESCAPE_RELAX mode, keep it verbatim in the
                                         * output.
                                         *
                                         * Unbalanced quotes will only be allowed in EXTRACT_RELAX
                                         * mode, EXTRACT_CUNESCAPE_RELAX mode does not allow them.
                                         */
                                        s[sz++] = '\\';
                                        goto finish_force_terminate;
                                }
                                if (flags & EXTRACT_RELAX)
                                        goto finish_force_terminate;
                                return -EINVAL;
                        }

                        if (flags & EXTRACT_CUNESCAPE) {
                                bool eight_bit = false;
                                char32_t u;

                                r = cunescape_one(*p, (size_t) -1, &u, &eight_bit);
                                if (r < 0) {
                                        if (flags & EXTRACT_CUNESCAPE_RELAX) {
                                                s[sz++] = '\\';
                                                s[sz++] = c;
                                        } else
                                                return -EINVAL;
                                } else {
                                        (*p) += r - 1;

                                        if (eight_bit)
                                                s[sz++] = u;
                                        else
                                                sz += utf8_encode_unichar(s + sz, u);
                                }
                        } else
                                s[sz++] = c;

                        backslash = false;

                } else if (quote) {     /* inside either single or double quotes */
                        for (;; (*p) ++, c = **p) {
                                if (c == 0) {
                                        if (flags & EXTRACT_RELAX)
                                                goto finish_force_terminate;
                                        return -EINVAL;
                                } else if (c == quote) {        /* found the end quote */
                                        quote = 0;
                                        break;
                                } else if (c == '\\' && !(flags & EXTRACT_RETAIN_ESCAPE)) {
                                        backslash = true;
                                        break;
                                } else {
                                        if (!GREEDY_REALLOC(s, allocated, sz+2))
                                                return -ENOMEM;

                                        s[sz++] = c;
                                }
                        }

                } else {
                        for (;; (*p) ++, c = **p) {
                                if (c == 0)
                                        goto finish_force_terminate;
                                else if ((c == '\'' || c == '"') && (flags & EXTRACT_QUOTES)) {
                                        quote = c;
                                        break;
                                } else if (c == '\\' && !(flags & EXTRACT_RETAIN_ESCAPE)) {
                                        backslash = true;
                                        break;
                                } else if (strchr(separators, c)) {
                                        if (flags & EXTRACT_DONT_COALESCE_SEPARATORS) {
                                                (*p) ++;
                                                goto finish_force_next;
                                        }
                                        /* Skip additional coalesced separators. */
                                        for (;; (*p) ++, c = **p) {
                                                if (c == 0)
                                                        goto finish_force_terminate;
                                                if (!strchr(separators, c))
                                                        break;
                                        }
                                        goto finish;

                                } else {
                                        if (!GREEDY_REALLOC(s, allocated, sz+2))
                                                return -ENOMEM;

                                        s[sz++] = c;
                                }
                        }
                }
        }

finish_force_terminate:
        *p = NULL;
finish:
        if (!s) {
                *p = NULL;
                *ret = NULL;
                return 0;
        }

finish_force_next:
        s[sz] = 0;
        *ret = s;
        s = NULL;

        return 1;
}

int extract_first_word_and_warn(
                const char **p,
                char **ret,
                const char *separators,
                ExtractFlags flags,
                const char *unit,
                const char *filename,
                unsigned line,
                const char *rvalue) {

        /* Try to unquote it, if it fails, warn about it and try again
         * but this time using EXTRACT_CUNESCAPE_RELAX to keep the
         * backslashes verbatim in invalid escape sequences. */

        const char *save;
        int r;

        save = *p;
        r = extract_first_word(p, ret, separators, flags);
        if (r >= 0)
                return r;

        if (r == -EINVAL && !(flags & EXTRACT_CUNESCAPE_RELAX)) {

                /* Retry it with EXTRACT_CUNESCAPE_RELAX. */
                *p = save;
                r = extract_first_word(p, ret, separators, flags|EXTRACT_CUNESCAPE_RELAX);
                if (r >= 0) {
                        /* It worked this time, hence it must have been an invalid escape sequence we could correct. */
                        log_syntax(unit, LOG_WARNING, filename, line, EINVAL, "Invalid escape sequences in line, correcting: \"%s\"", rvalue);
                        return r;
                }

                /* If it's still EINVAL; then it must be unbalanced quoting, report this. */
                if (r == -EINVAL)
                        return log_syntax(unit, LOG_ERR, filename, line, r, "Unbalanced quoting, ignoring: \"%s\"", rvalue);
        }

        /* Can be any error, report it */
        return log_syntax(unit, LOG_ERR, filename, line, r, "Unable to decode word \"%s\", ignoring: %m", rvalue);
}

int extract_many_words(const char **p, const char *separators, ExtractFlags flags, ...) {
        va_list ap;
        char **l;
        int n = 0, i, c, r;

        /* Parses a number of words from a string, stripping any
         * quotes if necessary. */

        assert(p);

        /* Count how many words are expected */
        va_start(ap, flags);
        for (;;) {
                if (!va_arg(ap, char **))
                        break;
                n++;
        }
        va_end(ap);

        if (n <= 0)
                return 0;

        /* Read all words into a temporary array */
        l = newa0(char*, n);
        for (c = 0; c < n; c++) {

                r = extract_first_word(p, &l[c], separators, flags);
                if (r < 0) {
                        int j;

                        for (j = 0; j < c; j++)
                                free(l[j]);

                        return r;
                }

                if (r == 0)
                        break;
        }

        /* If we managed to parse all words, return them in the passed
         * in parameters */
        va_start(ap, flags);
        for (i = 0; i < n; i++) {
                char **v;

                v = va_arg(ap, char **);
                assert(v);

                *v = l[i];
        }
        va_end(ap);

        return c;
}