Systemd/src/basic/extract-word.c
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

291 lines
11 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
***/
#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;
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 (IN_SET(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 = 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_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. */
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) {
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;
}