/src/systemd/src/basic/extract-word.c

Source
/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include "alloc-util.h"
#include "escape.h"
#include "extract-word.h"
#include "log.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 sz = 0;
        char quote = 0;                 /* 0 or ' or " */
        bool backslash = false;         /* whether we've just seen a backslash */
        char c;
        int r;

        assert(p);
        assert(ret);
        assert(!FLAGS_SET(flags, EXTRACT_KEEP_QUOTE | EXTRACT_UNQUOTE));

        /* Bail early if called after last value or with no input */
        if (!*p)
                goto finish;
        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, 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) {
                                if (!(flags & EXTRACT_RETAIN_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, sz+1))
                                return -ENOMEM;
                        break;
                }
        }

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

                        if (c == 0) {
                                if ((flags & EXTRACT_UNESCAPE_RELAX) &&
                                    (quote == 0 || flags & EXTRACT_RELAX)) {
                                        /* If we find an unquoted trailing backslash and we're in
                                         * EXTRACT_UNESCAPE_RELAX mode, keep it verbatim in the
                                         * output.
                                         *
                                         * Unbalanced quotes will only be allowed in EXTRACT_RELAX
                                         * mode, EXTRACT_UNESCAPE_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|EXTRACT_UNESCAPE_SEPARATORS|EXTRACT_UNESCAPE_RELAX)) {
                                bool eight_bit = false;
                                char32_t u;

                                if ((flags & EXTRACT_CUNESCAPE) &&
                                    (r = cunescape_one(*p, SIZE_MAX, &u, &eight_bit, false)) >= 0) {
                                        /* A valid escaped sequence */
                                        assert(r >= 1);

                                        (*p) += r - 1;

                                        if (eight_bit)
                                                s[sz++] = u;
                                        else
                                                sz += utf8_encode_unichar(s + sz, u);
                                } else if ((flags & EXTRACT_UNESCAPE_SEPARATORS) &&
                                           (strchr(separators, **p) || **p == '\\'))
                                        /* An escaped separator char or the escape char itself */
                                        s[sz++] = c;
                                else if (flags & EXTRACT_UNESCAPE_RELAX) {
                                        s[sz++] = '\\';
                                        s[sz++] = c;
                                } else
                                        return -EINVAL;
                        } else
                                s[sz++] = c;

                        backslash = false;

                } else if (quote != 0) {     /* 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;
                                        if (flags & EXTRACT_UNQUOTE)
                                                break;
                                } else if (c == '\\' && !(flags & EXTRACT_RETAIN_ESCAPE)) {
                                        backslash = true;
                                        break;
                                }

                                if (!GREEDY_REALLOC(s, sz+2))
                                        return -ENOMEM;

                                s[sz++] = c;

                                if (quote == 0)
                                        break;
                        }

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

                                }

                                if (!GREEDY_REALLOC(s, sz+2))
                                        return -ENOMEM;

                                s[sz++] = c;

                                if (quote != 0)
                                        break;
                        }
                }
        }

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

finish_force_next:
        s[sz] = 0;
        *ret = TAKE_PTR(s);

        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_UNESCAPE_RELAX to keep the
         * backslashes verbatim in invalid escape sequences. */

        const char *save;
        int r;

        assert(p);
        assert(ret);

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

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

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

/* We pass ExtractFlags as unsigned int (to avoid undefined behaviour when passing
 * an object that undergoes default argument promotion as an argument to va_start).
 * Let's make sure that ExtractFlags fits into an unsigned int. */
assert_cc(sizeof(enum ExtractFlags) <= sizeof(unsigned));

int extract_many_words_internal(const char **p, const char *separators, unsigned flags, ...) {
        va_list ap;
        unsigned n = 0;
        int 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);
        while (va_arg(ap, char**))
                n++;
        va_end(ap);

        if (n == 0)
                return 0;

        /* Read all words into a temporary array */
        char **l = newa0(char*, n);
        unsigned c;

        for (c = 0; c < n; c++) {
                r = extract_first_word(p, &l[c], separators, flags);
                if (r < 0) {
                        free_many_charp(l, c);
                        return r;
                }
                if (r == 0)
                        break;
        }

        /* If we managed to parse all words, return them in the passed in parameters */
        va_start(ap, flags);
        FOREACH_ARRAY(i, l, n) {
                char **v = ASSERT_PTR(va_arg(ap, char**));
                *v = *i;
        }
        va_end(ap);

        return c;
}

Coverage Report

Created: 2026-09-14 06:51

Line	Count	Source
1		/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3		#include "alloc-util.h"
4		#include "escape.h"
5		#include "extract-word.h"
6		#include "log.h"
7		#include "string-util.h"
8		#include "utf8.h"
9
10	12.9M	int extract_first_word(const char p, char ret, const char *separators, ExtractFlags flags) {
11	12.9M	_cleanup_free_ char *s = NULL;
12	12.9M	size_t sz = 0;
13	12.9M	char quote = 0; /* 0 or ' or " */
14	12.9M	bool backslash = false; /* whether we've just seen a backslash */
15	12.9M	char c;
16	12.9M	int r;
17
18	12.9M	assert(p);
19	12.9M	assert(ret);
20	12.9M	assert(!FLAGS_SET(flags, EXTRACT_KEEP_QUOTE \| EXTRACT_UNQUOTE));
21
22		/* Bail early if called after last value or with no input */
23	12.9M	if (!*p)
24	4.08M	goto finish;
25	8.83M	c = **p;
26
27	8.83M	if (!separators)
28	4.67M	separators = WHITESPACE;
29
30		/* Parses the first word of a string, and returns it in
31		* *ret. Removes all quotes in the process. When parsing fails
32		* (because of an uneven number of quotes or similar), leaves
33		* the pointer p at the first invalid character. /
34
35	8.83M	if (flags & EXTRACT_DONT_COALESCE_SEPARATORS)
36	717k	if (!GREEDY_REALLOC(s, sz+1))
37	0	return -ENOMEM;
38
39	8.84M	for (;; (p)++, c = *p) {
40	8.84M	if (c == 0)
41	399k	goto finish_force_terminate;
42	8.44M	else if (strchr(separators, c)) {
43	343k	if (flags & EXTRACT_DONT_COALESCE_SEPARATORS) {
44	335k	if (!(flags & EXTRACT_RETAIN_SEPARATORS))
45	334k	(*p)++;
46	335k	goto finish_force_next;
47	335k	}
48	8.10M	} else {
49		/* We found a non-blank character, so we will always
50		* want to return a string (even if it is empty),
51		* allocate it here. */
52	8.10M	if (!GREEDY_REALLOC(s, sz+1))
53	0	return -ENOMEM;
54	8.10M	break;
55	8.10M	}
56	8.84M	}
57
58	8.46M	for (;; (p)++, c = *p) {
59	8.46M	if (backslash) {
60	182k	if (!GREEDY_REALLOC(s, sz+7))
61	0	return -ENOMEM;
62
63	182k	if (c == 0) {
64	20.7k	if ((flags & EXTRACT_UNESCAPE_RELAX) &&
65	111	(quote == 0 \|\| flags & EXTRACT_RELAX)) {
66		/* If we find an unquoted trailing backslash and we're in
67		* EXTRACT_UNESCAPE_RELAX mode, keep it verbatim in the
68		* output.
69		*
70		* Unbalanced quotes will only be allowed in EXTRACT_RELAX
71		* mode, EXTRACT_UNESCAPE_RELAX mode does not allow them.
72		*/
73	75	s[sz++] = '\\';
74	75	goto finish_force_terminate;
75	75	}
76	20.7k	if (flags & EXTRACT_RELAX)
77	1.73k	goto finish_force_terminate;
78	18.9k	return -EINVAL;
79	20.7k	}
80
81	161k	if (flags & (EXTRACT_CUNESCAPE\|EXTRACT_UNESCAPE_SEPARATORS\|EXTRACT_UNESCAPE_RELAX)) {
82	89.5k	bool eight_bit = false;
83	89.5k	char32_t u;
84
85	89.5k	if ((flags & EXTRACT_CUNESCAPE) &&
86	89.5k	(r = cunescape_one(*p, SIZE_MAX, &u, &eight_bit, false)) >= 0) {
87		/* A valid escaped sequence */
88	58.8k	assert(r >= 1);
89
90	58.8k	(*p) += r - 1;
91
92	58.8k	if (eight_bit)
93	35.8k	s[sz++] = u;
94	22.9k	else
95	22.9k	sz += utf8_encode_unichar(s + sz, u);
96	58.8k	} else if ((flags & EXTRACT_UNESCAPE_SEPARATORS) &&
97	5.07k	(strchr(separators, p) \|\| p == '\\'))
98		/* An escaped separator char or the escape char itself */
99	3.43k	s[sz++] = c;
100	27.2k	else if (flags & EXTRACT_UNESCAPE_RELAX) {
101	8.73k	s[sz++] = '\\';
102	8.73k	s[sz++] = c;
103	8.73k	} else
104	18.4k	return -EINVAL;
105	89.5k	} else
106	71.9k	s[sz++] = c;
107
108	142k	backslash = false;
109
110	8.27M	} else if (quote != 0) { /* inside either single or double quotes */
111	1.48M	for (;; (p)++, c = *p) {
112	1.48M	if (c == 0) {
113	12.7k	if (flags & EXTRACT_RELAX)
114	1.49k	goto finish_force_terminate;
115	11.2k	return -EINVAL;
116	1.46M	} else if (c == quote) { /* found the end quote */
117	11.2k	quote = 0;
118	11.2k	if (flags & EXTRACT_UNQUOTE)
119	11.2k	break;
120	1.45M	} else if (c == '\\' && !(flags & EXTRACT_RETAIN_ESCAPE)) {
121	22.4k	backslash = true;
122	22.4k	break;
123	22.4k	}
124
125	1.43M	if (!GREEDY_REALLOC(s, sz+2))
126	0	return -ENOMEM;
127
128	1.43M	s[sz++] = c;
129
130	1.43M	if (quote == 0)
131	0	break;
132	1.43M	}
133
134	8.23M	} else {
135	211M	for (;; (p)++, c = *p) {
136	211M	if (c == 0)
137	4.27M	goto finish_force_terminate;
138	207M	else if (IN_SET(c, '\'', '"') && (flags & (EXTRACT_KEEP_QUOTE \| EXTRACT_UNQUOTE))) {
139	24.1k	quote = c;
140	24.1k	if (flags & EXTRACT_UNQUOTE)
141	24.1k	break;
142	207M	} else if (c == '\\' && !(flags & EXTRACT_RETAIN_ESCAPE)) {
143	159k	backslash = true;
144	159k	break;
145	207M	} else if (strchr(separators, c)) {
146	3.77M	if (flags & EXTRACT_DONT_COALESCE_SEPARATORS) {
147	102k	if (!(flags & EXTRACT_RETAIN_SEPARATORS))
148	102k	(*p)++;
149	102k	goto finish_force_next;
150	102k	}
151	3.67M	if (!(flags & EXTRACT_RETAIN_SEPARATORS))
152		/* Skip additional coalesced separators. */
153	7.44M	for (;; (p)++, c = *p) {
154	7.44M	if (c == 0)
155	3.24k	goto finish_force_terminate;
156	7.44M	if (!strchr(separators, c))
157	3.66M	break;
158	7.44M	}
159	3.66M	goto finish;
160
161	3.67M	}
162
163	203M	if (!GREEDY_REALLOC(s, sz+2))
164	0	return -ENOMEM;
165
166	203M	s[sz++] = c;
167
168	203M	if (quote != 0)
169	0	break;
170	203M	}
171	8.23M	}
172	8.46M	}
173
174	4.68M	finish_force_terminate:
175	4.68M	*p = NULL;
176	12.4M	finish:
177	12.4M	if (!s) {
178	4.47M	*p = NULL;
179	4.47M	*ret = NULL;
180	4.47M	return 0;
181	4.47M	}
182
183	8.40M	finish_force_next:
184	8.40M	s[sz] = 0;
185	8.40M	*ret = TAKE_PTR(s);
186
187	8.40M	return 1;
188	12.4M	}
189
190		int extract_first_word_and_warn(
191		const char **p,
192		char **ret,
193		const char *separators,
194		ExtractFlags flags,
195		const char *unit,
196		const char *filename,
197		unsigned line,
198	14.4k	const char *rvalue) {
199
200		/* Try to unquote it, if it fails, warn about it and try again
201		* but this time using EXTRACT_UNESCAPE_RELAX to keep the
202		* backslashes verbatim in invalid escape sequences. */
203
204	14.4k	const char *save;
205	14.4k	int r;
206
207	14.4k	assert(p);
208	14.4k	assert(ret);
209
210	14.4k	save = *p;
211	14.4k	r = extract_first_word(p, ret, separators, flags);
212	14.4k	if (r >= 0)
213	9.91k	return r;
214
215	4.53k	if (r == -EINVAL && !(flags & EXTRACT_UNESCAPE_RELAX)) {
216
217		/* Retry it with EXTRACT_UNESCAPE_RELAX. */
218	4.53k	*p = save;
219	4.53k	r = extract_first_word(p, ret, separators, flags\|EXTRACT_UNESCAPE_RELAX);
220	4.53k	if (r >= 0) {
221		/* It worked this time, hence it must have been an invalid escape sequence. */
222	4.18k	log_syntax(unit, LOG_WARNING, filename, line, EINVAL, "Ignoring unknown escape sequences: \"%s\"", *ret);
223	4.18k	return r;
224	4.18k	}
225
226		/* If it's still EINVAL; then it must be unbalanced quoting, report this. */
227	349	if (r == -EINVAL)
228	349	return log_syntax(unit, LOG_ERR, filename, line, r, "Unbalanced quoting, ignoring: \"%s\"", rvalue);
229	349	}
230
231		/* Can be any error, report it */
232	0	return log_syntax(unit, LOG_ERR, filename, line, r, "Unable to decode word \"%s\", ignoring: %m", rvalue);
233	4.53k	}
234
235		/* We pass ExtractFlags as unsigned int (to avoid undefined behaviour when passing
236		* an object that undergoes default argument promotion as an argument to va_start).
237		* Let's make sure that ExtractFlags fits into an unsigned int. */
238		assert_cc(sizeof(enum ExtractFlags) <= sizeof(unsigned));
239
240	195k	int extract_many_words_internal(const char *p, const char separators, unsigned flags, ...) {
241	195k	va_list ap;
242	195k	unsigned n = 0;
243	195k	int r;
244
245		/* Parses a number of words from a string, stripping any quotes if necessary. */
246
247	195k	assert(p);
248
249		/* Count how many words are expected */
250	195k	va_start(ap, flags);
251	195k	while (va_arg(ap, char**))
252	525k	n++;
253	195k	va_end(ap);
254
255	195k	if (n == 0)
256	0	return 0;
257
258		/* Read all words into a temporary array */
259	195k	char *l = newa0(char, n);
260	195k	unsigned c;
261
262	489k	for (c = 0; c < n; c++) {
263	432k	r = extract_first_word(p, &l[c], separators, flags);
264	432k	if (r < 0) {
265	6.57k	free_many_charp(l, c);
266	6.57k	return r;
267	6.57k	}
268	425k	if (r == 0)
269	132k	break;
270	425k	}
271
272		/* If we managed to parse all words, return them in the passed in parameters */
273	195k	va_start(ap, flags);
274	507k	FOREACH_ARRAY(i, l, n) {
275	507k	char v = ASSERT_PTR(va_arg(ap, char));
276	507k	v = i;
277	507k	}
278	189k	va_end(ap);
279
280	189k	return c;
281	195k	}