cosmopolitan/net/http/encodehttpheadervalue.c
Justine Tunney a1677d605a Transcode ISO-8859-1 in HTTP headers
If we keep making changes like this, redbean might not be a toy anymore.
Additional steps are also being taken now to prevent ANSI control codes
sent by the client from slipping into logs.
2021-03-28 00:10:17 -07:00

85 lines
3.4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2021 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/errno.h"
#include "libc/mem/mem.h"
#include "libc/str/str.h"
#include "libc/str/thompike.h"
#include "net/http/http.h"
/**
* Encodes HTTP header value.
*
* This operation involves the following:
*
* 1. Trim whitespace.
* 2. Turn UTF-8 into ISO-8859-1.
* 3. Make sure no C0 or C1 control codes are present (except tab).
*
* If the input value isn't thompson-pike encoded then this
* implementation will fall back to latin1 in most cases.
*
* @param data is input value
* @param size if -1 implies strlen
* @param out_size if non-NULL receives output length on success
* @return allocated NUL-terminated string, or NULL w/ errno
*/
char *EncodeHttpHeaderValue(const char *data, size_t size, size_t *out_size) {
bool t;
wint_t x;
char *r, *q;
const char *p, *e;
if (size == -1) size = strlen(data);
if ((r = malloc(size + 1))) {
t = 0;
q = r;
p = data;
e = p + size;
while (p < e) {
x = *p++ & 0xff;
if (x >= 0300) {
if (p < e && ThomPikeCont(*p)) {
if (ThomPikeLen(x) == 2) {
x = ThomPikeMerge(ThomPikeByte(x), *p++);
} else {
x = 0;
}
}
}
if (!t) {
if (x == ' ' || x == '\t') {
continue;
} else {
t = true;
}
}
if ((0x20 <= x && x <= 0x7E) || (0xA0 <= x && x <= 0xFF) || x == '\t') {
*q++ = x;
} else {
free(r);
errno = EILSEQ;
return NULL;
}
}
while (q > r && (q[-1] == ' ' || q[-1] == '\t')) --q;
if (out_size) *out_size = q - r;
*q++ = '\0';
if ((q = realloc(r, q - r))) r = q;
}
return r;
}