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/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2019, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file kvline.c
*
* \brief Manipulating lines of key-value pairs.
**/
#include "orconfig.h"
#include "lib/container/smartlist.h"
#include "lib/encoding/confline.h"
#include "lib/encoding/cstring.h"
#include "lib/encoding/kvline.h"
#include "lib/malloc/malloc.h"
#include "lib/string/compat_ctype.h"
#include "lib/string/printf.h"
#include "lib/string/util_string.h"
#include "lib/log/escape.h"
#include "lib/log/util_bug.h"
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
/** Return true iff we need to quote and escape the string <b>s</b> to encode
* it. */
static bool
needs_escape(const char *s, bool as_keyless_val)
{
if (as_keyless_val && *s == 0)
return true;
for (; *s; ++s) {
if (*s >= 127 || TOR_ISSPACE(*s) || ! TOR_ISPRINT(*s) ||
*s == '\'' || *s == '\"') {
return true;
}
}
return false;
}
/**
* Return true iff the key in <b>line</b> is not set.
**/
static bool
line_has_no_key(const config_line_t *line)
{
return line->key == NULL || strlen(line->key) == 0;
}
/**
* Return true iff the all the lines in <b>line</b> can be encoded
* using <b>flags</b>.
**/
static bool
kvline_can_encode_lines(const config_line_t *line, unsigned flags)
{
for ( ; line; line = line->next) {
const bool keyless = line_has_no_key(line);
if (keyless) {
if (! (flags & KV_OMIT_KEYS)) {
/* If KV_OMIT_KEYS is not set, we can't encode a line with no key. */
return false;
}
if (strchr(line->value, '=') && !( flags & KV_QUOTED)) {
/* We can't have a keyless value with = without quoting it. */
return false;
}
}
if (needs_escape(line->value, keyless) && ! (flags & KV_QUOTED)) {
/* If KV_QUOTED is false, we can't encode a value that needs quotes. */
return false;
}
if (line->key && strlen(line->key) &&
(needs_escape(line->key, false) || strchr(line->key, '='))) {
/* We can't handle keys that need quoting. */
return false;
}
}
return true;
}
/**
* Encode a linked list of lines in <b>line</b> as a series of 'Key=Value'
* pairs, using the provided <b>flags</b> to encode it. Return a newly
* allocated string on success, or NULL on failure.
*
* If KV_QUOTED is set in <b>flags</b>, then all values that contain
* spaces or unusual characters are escaped and quoted. Otherwise, such
* values are not allowed.
*
* If KV_OMIT_KEYS is set in <b>flags</b>, then pairs with empty keys are
* allowed, and are encoded as 'Value'. Otherwise, such pairs are not
* allowed.
*/
char *
kvline_encode(const config_line_t *line,
unsigned flags)
{
if (!kvline_can_encode_lines(line, flags))
return NULL;
smartlist_t *elements = smartlist_new();
for (; line; line = line->next) {
const char *k = "";
const char *eq = "=";
const char *v = "";
const bool keyless = line_has_no_key(line);
bool esc = needs_escape(line->value, keyless);
char *tmp = NULL;
if (! keyless) {
k = line->key;
} else {
eq = "";
if (strchr(line->value, '=')) {
esc = true;
}
}
if (esc) {
tmp = esc_for_log(line->value);
v = tmp;
} else {
v = line->value;
}
smartlist_add_asprintf(elements, "%s%s%s", k, eq, v);
tor_free(tmp);
}
char *result = smartlist_join_strings(elements, " ", 0, NULL);
SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp));
smartlist_free(elements);
return result;
}
/**
* Decode a <b>line</b> containing a series of space-separated 'Key=Value'
* pairs, using the provided <b>flags</b> to decode it. Return a newly
* allocated list of pairs on success, or NULL on failure.
*
* If KV_QUOTED is set in <b>flags</b>, then (double-)quoted values are
* allowed. Otherwise, such values are not allowed.
*
* If KV_OMIT_KEYS is set in <b>flags</b>, then values without keys are
* allowed. Otherwise, such values are not allowed.
*/
config_line_t *
kvline_parse(const char *line, unsigned flags)
{
const char *cp = line, *cplast = NULL;
bool omit_keys = (flags & KV_OMIT_KEYS) != 0;
bool quoted = (flags & KV_QUOTED) != 0;
config_line_t *result = NULL;
config_line_t **next_line = &result;
char *key = NULL;
char *val = NULL;
while (*cp) {
key = val = NULL;
{
size_t idx = strspn(cp, " \t\r\v\n");
cp += idx;
}
if (BUG(cp == cplast)) {
/* If we didn't parse anything, this code is broken. */
goto err; // LCOV_EXCL_LINE
}
cplast = cp;
if (! *cp)
break; /* End of string; we're done. */
/* Possible formats are K=V, K="V", V, and "V", depending on flags. */
/* Find the key. */
if (*cp != '\"') {
size_t idx = strcspn(cp, " \t\r\v\n=");
if (cp[idx] == '=') {
key = tor_memdup_nulterm(cp, idx);
cp += idx + 1;
} else {
if (!omit_keys)
goto err;
}
}
if (*cp == '\"') {
/* The type is "V". */
if (!quoted)
goto err;
size_t len=0;
cp = unescape_string(cp, &val, &len);
if (cp == NULL || len != strlen(val)) {
// The string contains a NUL or is badly coded.
goto err;
}
} else {
size_t idx = strcspn(cp, " \t\r\v\n");
val = tor_memdup_nulterm(cp, idx);
cp += idx;
}
if (key && strlen(key) == 0) {
/* We don't allow empty keys. */
goto err;
}
*next_line = tor_malloc_zero(sizeof(config_line_t));
(*next_line)->key = key ? key : tor_strdup("");
(*next_line)->value = val;
next_line = &(*next_line)->next;
key = val = NULL;
}
if (!kvline_can_encode_lines(result, flags)) {
goto err;
}
return result;
err:
tor_free(key);
tor_free(val);
config_free_lines(result);
return NULL;
}
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