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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.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 "strv.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(const char **p, const char *separators, unsigned 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) {
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);
for (i = 0; i < n; i++) {
char **v;
v = va_arg(ap, char **);
assert(v);
*v = l[i];
}
va_end(ap);
return c;
}
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