[thirdparty/systemd.git] / src / basic / extract-word.c

/* 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)) {
                                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;

        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;
}
Commit	Line	Data
	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	int extract_first_word(const char p, char ret, const char *separators, ExtractFlags flags) {
	11	_cleanup_free_ char *s = NULL;
	12	size_t sz = 0;
	13	char quote = 0; /* 0 or ' or " */
	14	bool backslash = false; /* whether we've just seen a backslash */
	15	char c;
	16	int r;
	17
	18	assert(p);
	19	assert(ret);
	20	assert(!FLAGS_SET(flags, EXTRACT_KEEP_QUOTE \| EXTRACT_UNQUOTE));
	21
	22	/* Bail early if called after last value or with no input */
	23	if (!*p)
	24	goto finish;
	25	c = **p;
	26
	27	if (!separators)
	28	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	if (flags & EXTRACT_DONT_COALESCE_SEPARATORS)
	36	if (!GREEDY_REALLOC(s, sz+1))
	37	return -ENOMEM;
	38
	39	for (;; (p)++, c = *p) {
	40	if (c == 0)
	41	goto finish_force_terminate;
	42	else if (strchr(separators, c)) {
	43	if (flags & EXTRACT_DONT_COALESCE_SEPARATORS) {
	44	if (!(flags & EXTRACT_RETAIN_SEPARATORS))
	45	(*p)++;
	46	goto finish_force_next;
	47	}
	48	} 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	if (!GREEDY_REALLOC(s, sz+1))
	53	return -ENOMEM;
	54	break;
	55	}
	56	}
	57
	58	for (;; (p)++, c = *p) {
	59	if (backslash) {
	60	if (!GREEDY_REALLOC(s, sz+7))
	61	return -ENOMEM;
	62
	63	if (c == 0) {
	64	if ((flags & EXTRACT_UNESCAPE_RELAX) &&
	65	(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	s[sz++] = '\\';
	74	goto finish_force_terminate;
	75	}
	76	if (flags & EXTRACT_RELAX)
	77	goto finish_force_terminate;
	78	return -EINVAL;
	79	}
	80
	81	if (flags & (EXTRACT_CUNESCAPE\|EXTRACT_UNESCAPE_SEPARATORS)) {
	82	bool eight_bit = false;
	83	char32_t u;
	84
	85	if ((flags & EXTRACT_CUNESCAPE) &&
	86	(r = cunescape_one(*p, SIZE_MAX, &u, &eight_bit, false)) >= 0) {
	87	/* A valid escaped sequence */
	88	assert(r >= 1);
	89
	90	(*p) += r - 1;
	91
	92	if (eight_bit)
	93	s[sz++] = u;
	94	else
	95	sz += utf8_encode_unichar(s + sz, u);
	96	} else if ((flags & EXTRACT_UNESCAPE_SEPARATORS) &&
	97	(strchr(separators, p) \|\| p == '\\'))
	98	/* An escaped separator char or the escape char itself */
	99	s[sz++] = c;
	100	else if (flags & EXTRACT_UNESCAPE_RELAX) {
	101	s[sz++] = '\\';
	102	s[sz++] = c;
	103	} else
	104	return -EINVAL;
	105	} else
	106	s[sz++] = c;
	107
	108	backslash = false;
	109
	110	} else if (quote != 0) { /* inside either single or double quotes */
	111	for (;; (p)++, c = *p) {
	112	if (c == 0) {
	113	if (flags & EXTRACT_RELAX)
	114	goto finish_force_terminate;
	115	return -EINVAL;
	116	} else if (c == quote) { /* found the end quote */
	117	quote = 0;
	118	if (flags & EXTRACT_UNQUOTE)
	119	break;
	120	} else if (c == '\\' && !(flags & EXTRACT_RETAIN_ESCAPE)) {
	121	backslash = true;
	122	break;
	123	}
	124
	125	if (!GREEDY_REALLOC(s, sz+2))
	126	return -ENOMEM;
	127
	128	s[sz++] = c;
	129
	130	if (quote == 0)
	131	break;
	132	}
	133
	134	} else {
	135	for (;; (p)++, c = *p) {
	136	if (c == 0)
	137	goto finish_force_terminate;
	138	else if (IN_SET(c, '\'', '"') && (flags & (EXTRACT_KEEP_QUOTE \| EXTRACT_UNQUOTE))) {
	139	quote = c;
	140	if (flags & EXTRACT_UNQUOTE)
	141	break;
	142	} else if (c == '\\' && !(flags & EXTRACT_RETAIN_ESCAPE)) {
	143	backslash = true;
	144	break;
	145	} else if (strchr(separators, c)) {
	146	if (flags & EXTRACT_DONT_COALESCE_SEPARATORS) {
	147	if (!(flags & EXTRACT_RETAIN_SEPARATORS))
	148	(*p)++;
	149	goto finish_force_next;
	150	}
	151	if (!(flags & EXTRACT_RETAIN_SEPARATORS))
	152	/* Skip additional coalesced separators. */
	153	for (;; (p)++, c = *p) {
	154	if (c == 0)
	155	goto finish_force_terminate;
	156	if (!strchr(separators, c))
	157	break;
	158	}
	159	goto finish;
	160
	161	}
	162
	163	if (!GREEDY_REALLOC(s, sz+2))
	164	return -ENOMEM;
	165
	166	s[sz++] = c;
	167
	168	if (quote != 0)
	169	break;
	170	}
	171	}
	172	}
	173
	174	finish_force_terminate:
	175	*p = NULL;
	176	finish:
	177	if (!s) {
	178	*p = NULL;
	179	*ret = NULL;
	180	return 0;
	181	}
	182
	183	finish_force_next:
	184	s[sz] = 0;
	185	*ret = TAKE_PTR(s);
	186
	187	return 1;
	188	}
	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	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	const char *save;
	205	int r;
	206
	207	save = *p;
	208	r = extract_first_word(p, ret, separators, flags);
	209	if (r >= 0)
	210	return r;
	211
	212	if (r == -EINVAL && !(flags & EXTRACT_UNESCAPE_RELAX)) {
	213
	214	/* Retry it with EXTRACT_UNESCAPE_RELAX. */
	215	*p = save;
	216	r = extract_first_word(p, ret, separators, flags\|EXTRACT_UNESCAPE_RELAX);
	217	if (r >= 0) {
	218	/* It worked this time, hence it must have been an invalid escape sequence. */
	219	log_syntax(unit, LOG_WARNING, filename, line, EINVAL, "Ignoring unknown escape sequences: \"%s\"", *ret);
	220	return r;
	221	}
	222
	223	/* If it's still EINVAL; then it must be unbalanced quoting, report this. */
	224	if (r == -EINVAL)
	225	return log_syntax(unit, LOG_ERR, filename, line, r, "Unbalanced quoting, ignoring: \"%s\"", rvalue);
	226	}
	227
	228	/* Can be any error, report it */
	229	return log_syntax(unit, LOG_ERR, filename, line, r, "Unable to decode word \"%s\", ignoring: %m", rvalue);
	230	}
	231
	232	/* We pass ExtractFlags as unsigned int (to avoid undefined behaviour when passing
	233	* an object that undergoes default argument promotion as an argument to va_start).
	234	* Let's make sure that ExtractFlags fits into an unsigned int. */
	235	assert_cc(sizeof(enum ExtractFlags) <= sizeof(unsigned));
	236
	237	int extract_many_words_internal(const char *p, const char separators, unsigned flags, ...) {
	238	va_list ap;
	239	unsigned n = 0;
	240	int r;
	241
	242	/* Parses a number of words from a string, stripping any quotes if necessary. */
	243
	244	assert(p);
	245
	246	/* Count how many words are expected */
	247	va_start(ap, flags);
	248	while (va_arg(ap, char**))
	249	n++;
	250	va_end(ap);
	251
	252	if (n == 0)
	253	return 0;
	254
	255	/* Read all words into a temporary array */
	256	char *l = newa0(char, n);
	257	unsigned c;
	258
	259	for (c = 0; c < n; c++) {
	260	r = extract_first_word(p, &l[c], separators, flags);
	261	if (r < 0) {
	262	free_many_charp(l, c);
	263	return r;
	264	}
	265	if (r == 0)
	266	break;
	267	}
	268
	269	/* If we managed to parse all words, return them in the passed in parameters */
	270	va_start(ap, flags);
	271	FOREACH_ARRAY(i, l, n) {
	272	char v = ASSERT_PTR(va_arg(ap, char));
	273	v = i;
	274	}
	275	va_end(ap);
	276
	277	return c;
	278	}