/*=========================================================================*\
* MIME support functions
* LuaSocket toolkit
\*=========================================================================*/
#include <string.h>
#include "lua.h"
#include "lauxlib.h"
#if !defined(LUA_VERSION_NUM) || (LUA_VERSION_NUM < 501)
#include "compat-5.1.h"
#endif
#include "mime.h"
/*=========================================================================*\
* Don't want to trust escape character constants
\*=========================================================================*/
typedef unsigned char UC;
static const char CRLF[] = "\r\n";
static const char EQCRLF[] = "=\r\n";
/*=========================================================================*\
* Internal function prototypes.
\*=========================================================================*/
static int mime_global_wrp(lua_State *L);
static int mime_global_b64(lua_State *L);
static int mime_global_unb64(lua_State *L);
static int mime_global_qp(lua_State *L);
static int mime_global_unqp(lua_State *L);
static int mime_global_qpwrp(lua_State *L);
static int mime_global_eol(lua_State *L);
static int mime_global_dot(lua_State *L);
static size_t dot(int c, size_t state, luaL_Buffer *buffer);
static void b64setup(UC *base);
static size_t b64encode(UC c, UC *input, size_t size, luaL_Buffer *buffer);
static size_t b64pad(const UC *input, size_t size, luaL_Buffer *buffer);
static size_t b64decode(UC c, UC *input, size_t size, luaL_Buffer *buffer);
static void qpsetup(UC *class, UC *unbase);
static void qpquote(UC c, luaL_Buffer *buffer);
static size_t qpdecode(UC c, UC *input, size_t size, luaL_Buffer *buffer);
static size_t qpencode(UC c, UC *input, size_t size,
const char *marker, luaL_Buffer *buffer);
static size_t qppad(UC *input, size_t size, luaL_Buffer *buffer);
/* code support functions */
static luaL_Reg func[] = {
{ "dot", mime_global_dot },
{ "b64", mime_global_b64 },
{ "eol", mime_global_eol },
{ "qp", mime_global_qp },
{ "qpwrp", mime_global_qpwrp },
{ "unb64", mime_global_unb64 },
{ "unqp", mime_global_unqp },
{ "wrp", mime_global_wrp },
{ NULL, NULL }
};
/*-------------------------------------------------------------------------*\
* Quoted-printable globals
\*-------------------------------------------------------------------------*/
static UC qpclass[256];
static UC qpbase[] = "0123456789ABCDEF";
static UC qpunbase[256];
enum {QP_PLAIN, QP_QUOTED, QP_CR, QP_IF_LAST};
/*-------------------------------------------------------------------------*\
* Base64 globals
\*-------------------------------------------------------------------------*/
static const UC b64base[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static UC b64unbase[256];
/*=========================================================================*\
* Exported functions
\*=========================================================================*/
/*-------------------------------------------------------------------------*\
* Initializes module
\*-------------------------------------------------------------------------*/
MIME_API int luaopen_mime_core(lua_State *L)
{
#if LUA_VERSION_NUM > 501 && !defined(LUA_COMPAT_MODULE)
lua_newtable(L);
luaL_setfuncs(L, func, 0);
#else
luaL_openlib(L, "mime", func, 0);
#endif
/* make version string available to scripts */
lua_pushstring(L, "_VERSION");
lua_pushstring(L, MIME_VERSION);
lua_rawset(L, -3);
/* initialize lookup tables */
qpsetup(qpclass, qpunbase);
b64setup(b64unbase);
return 1;
}
/*=========================================================================*\
* Global Lua functions
\*=========================================================================*/
/*-------------------------------------------------------------------------*\
* Incrementaly breaks a string into lines. The string can have CRLF breaks.
* A, n = wrp(l, B, length)
* A is a copy of B, broken into lines of at most 'length' bytes.
* 'l' is how many bytes are left for the first line of B.
* 'n' is the number of bytes left in the last line of A.
\*-------------------------------------------------------------------------*/
static int mime_global_wrp(lua_State *L)
{
size_t size = 0;
int left = (int) luaL_checknumber(L, 1);
const UC *input = (UC *) luaL_optlstring(L, 2, NULL, &size);
const UC *last = input + size;
int length = (int) luaL_optnumber(L, 3, 76);
luaL_Buffer buffer;
/* end of input black-hole */
if (!input) {
/* if last line has not been terminated, add a line break */
if (left < length) lua_pushstring(L, CRLF);
/* otherwise, we are done */
else lua_pushnil(L);
lua_pushnumber(L, length);
return 2;
}
luaL_buffinit(L, &buffer);
while (input < last) {
switch (*input) {
case '\r':
break;
case '\n':
luaL_addstring(&buffer, CRLF);
left = length;
break;
default:
if (left <= 0) {
left = length;
luaL_addstring(&buffer, CRLF);
}
luaL_addchar(&buffer, *input);
left--;
break;
}
input++;
}
luaL_pushresult(&buffer);
lua_pushnumber(L, left);
return 2;
}
/*-------------------------------------------------------------------------*\
* Fill base64 decode map.
\*-------------------------------------------------------------------------*/
static void b64setup(UC *unbase)
{
int i;
for (i = 0; i <= 255; i++) unbase[i] = (UC) 255;
for (i = 0; i < 64; i++) unbase[b64base[i]] = (UC) i;
unbase['='] = 0;
}
/*-------------------------------------------------------------------------*\
* Acumulates bytes in input buffer until 3 bytes are available.
* Translate the 3 bytes into Base64 form and append to buffer.
* Returns new number of bytes in buffer.
\*-------------------------------------------------------------------------*/
static size_t b64encode(UC c, UC *input, size_t size,
luaL_Buffer *buffer)
{
input[size++] = c;
if (size == 3) {
UC code[4];
unsigned long value = 0;
value += input[0]; value <<= 8;
value += input[1]; value <<= 8;
value += input[2];
code[3] = b64base[value & 0x3f]; value >>= 6;
code[2] = b64base[value & 0x3f]; value >>= 6;
code[1] = b64base[value & 0x3f]; value >>= 6;
code[0] = b64base[value];
luaL_addlstring(buffer, (char *) code, 4);
size = 0;
}
return size;
}
/*-------------------------------------------------------------------------*\
* Encodes the Base64 last 1 or 2 bytes and adds padding '='
* Result, if any, is appended to buffer.
* Returns 0.
\*-------------------------------------------------------------------------*/
static size_t b64pad(const UC *input, size_t size,
luaL_Buffer *buffer)
{
unsigned long value = 0;
UC code[4] = {'=', '=', '=', '='};
switch (size) {
case 1:
value = input[0] << 4;
code[1] = b64base[value & 0x3f]; value >>= 6;
code[0] = b64base[value];
luaL_addlstring(buffer, (char *) code, 4);
break;
case 2:
value = input[0]; value <<= 8;
value |= input[1]; value <<= 2;
code[2] = b64base[value & 0x3f]; value >>= 6;
code[1] = b64base[value & 0x3f]; value >>= 6;
code[0] = b64base[value];
luaL_addlstring(buffer, (char *) code, 4);
break;
default:
break;
}
return 0;
}
/*-------------------------------------------------------------------------*\
* Acumulates bytes in input buffer until 4 bytes are available.
* Translate the 4 bytes from Base64 form and append to buffer.
* Returns new number of bytes in buffer.
\*-------------------------------------------------------------------------*/
static size_t b64decode(UC c, UC *input, size_t size,
luaL_Buffer *buffer)
{
/* ignore invalid characters */
if (b64unbase[c] > 64) return size;
input[size++] = c;
/* decode atom */
if (size == 4) {
UC decoded[3];
int valid, value = 0;
value = b64unbase[input[0]]; value <<= 6;
value |= b64unbase[input[1]]; value <<= 6;
value |= b64unbase[input[2]]; value <<= 6;
value |= b64unbase[input[3]];
decoded[2] = (UC) (value & 0xff); value >>= 8;
decoded[1] = (UC) (value & 0xff); value >>= 8;
decoded[0] = (UC) value;
/* take care of paddding */
valid = (input[2] == '=') ? 1 : (input[3] == '=') ? 2 : 3;
luaL_addlstring(buffer, (char *) decoded, valid);
return 0;
/* need more data */
} else return size;
}
/*-------------------------------------------------------------------------*\
* Incrementally applies the Base64 transfer content encoding to a string
* A, B = b64(C, D)
* A is the encoded version of the largest prefix of C .. D that is
* divisible by 3. B has the remaining bytes of C .. D, *without* encoding.
* The easiest thing would be to concatenate the two strings and
* encode the result, but we can't afford that or Lua would dupplicate
* every chunk we received.
\*-------------------------------------------------------------------------*/
static int mime_global_b64(lua_State *L)
{
UC atom[3];
size_t isize = 0, asize = 0;
const UC *input = (UC *) luaL_optlstring(L, 1, NULL, &isize);
const UC *last = input + isize;
luaL_Buffer buffer;
/* end-of-input blackhole */
if (!input) {
lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* make sure we don't confuse buffer stuff with arguments */
lua_settop(L, 2);
/* process first part of the input */
luaL_buffinit(L, &buffer);
while (input < last)
asize = b64encode(*input++, atom, asize, &buffer);
input = (UC *) luaL_optlstring(L, 2, NULL, &isize);
/* if second part is nil, we are done */
if (!input) {
size_t osize = 0;
asize = b64pad(atom, asize, &buffer);
luaL_pushresult(&buffer);
/* if the output is empty and the input is nil, return nil */
lua_tolstring(L, -1, &osize);
if (osize == 0) lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* otherwise process the second part */
last = input + isize;
while (input < last)
asize = b64encode(*input++, atom, asize, &buffer);
luaL_pushresult(&buffer);
lua_pushlstring(L, (char *) atom, asize);
return 2;
}
/*-------------------------------------------------------------------------*\
* Incrementally removes the Base64 transfer content encoding from a string
* A, B = b64(C, D)
* A is the encoded version of the largest prefix of C .. D that is
* divisible by 4. B has the remaining bytes of C .. D, *without* encoding.
\*-------------------------------------------------------------------------*/
static int mime_global_unb64(lua_State *L)
{
UC atom[4];
size_t isize = 0, asize = 0;
const UC *input = (UC *) luaL_optlstring(L, 1, NULL, &isize);
const UC *last = input + isize;
luaL_Buffer buffer;
/* end-of-input blackhole */
if (!input) {
lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* make sure we don't confuse buffer stuff with arguments */
lua_settop(L, 2);
/* process first part of the input */
luaL_buffinit(L, &buffer);
while (input < last)
asize = b64decode(*input++, atom, asize, &buffer);
input = (UC *) luaL_optlstring(L, 2, NULL, &isize);
/* if second is nil, we are done */
if (!input) {
size_t osize = 0;
luaL_pushresult(&buffer);
/* if the output is empty and the input is nil, return nil */
lua_tolstring(L, -1, &osize);
if (osize == 0) lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* otherwise, process the rest of the input */
last = input + isize;
while (input < last)
asize = b64decode(*input++, atom, asize, &buffer);
luaL_pushresult(&buffer);
lua_pushlstring(L, (char *) atom, asize);
return 2;
}
/*-------------------------------------------------------------------------*\
* Quoted-printable encoding scheme
* all (except CRLF in text) can be =XX
* CLRL in not text must be =XX=XX
* 33 through 60 inclusive can be plain
* 62 through 126 inclusive can be plain
* 9 and 32 can be plain, unless in the end of a line, where must be =XX
* encoded lines must be no longer than 76 not counting CRLF
* soft line-break are =CRLF
* To encode one byte, we need to see the next two.
* Worst case is when we see a space, and wonder if a CRLF is comming
\*-------------------------------------------------------------------------*/
/*-------------------------------------------------------------------------*\
* Split quoted-printable characters into classes
* Precompute reverse map for encoding
\*-------------------------------------------------------------------------*/
static void qpsetup(UC *cl, UC *unbase)
{
int i;
for (i = 0; i < 256; i++) cl[i] = QP_QUOTED;
for (i = 33; i <= 60; i++) cl[i] = QP_PLAIN;
for (i = 62; i <= 126; i++) cl[i] = QP_PLAIN;
cl['\t'] = QP_IF_LAST;
cl[' '] = QP_IF_LAST;
cl['\r'] = QP_CR;
for (i = 0; i < 256; i++) unbase[i] = 255;
unbase['0'] = 0; unbase['1'] = 1; unbase['2'] = 2;
unbase['3'] = 3; unbase['4'] = 4; unbase['5'] = 5;
unbase['6'] = 6; unbase['7'] = 7; unbase['8'] = 8;
unbase['9'] = 9; unbase['A'] = 10; unbase['a'] = 10;
unbase['B'] = 11; unbase['b'] = 11; unbase['C'] = 12;
unbase['c'] = 12; unbase['D'] = 13; unbase['d'] = 13;
unbase['E'] = 14; unbase['e'] = 14; unbase['F'] = 15;
unbase['f'] = 15;
}
/*-------------------------------------------------------------------------*\
* Output one character in form =XX
\*-------------------------------------------------------------------------*/
static void qpquote(UC c, luaL_Buffer *buffer)
{
luaL_addchar(buffer, '=');
luaL_addchar(buffer, qpbase[c >> 4]);
luaL_addchar(buffer, qpbase[c & 0x0F]);
}
/*-------------------------------------------------------------------------*\
* Accumulate characters until we are sure about how to deal with them.
* Once we are sure, output to the buffer, in the correct form.
\*-------------------------------------------------------------------------*/
static size_t qpencode(UC c, UC *input, size_t size,
const char *marker, luaL_Buffer *buffer)
{
input[size++] = c;
/* deal with all characters we can have */
while (size > 0) {
switch (qpclass[input[0]]) {
/* might be the CR of a CRLF sequence */
case QP_CR:
if (size < 2) return size;
if (input[1] == '\n') {
luaL_addstring(buffer, marker);
return 0;
} else qpquote(input[0], buffer);
break;
/* might be a space and that has to be quoted if last in line */
case QP_IF_LAST:
if (size < 3) return size;
/* if it is the last, quote it and we are done */
if (input[1] == '\r' && input[2] == '\n') {
qpquote(input[0], buffer);
luaL_addstring(buffer, marker);
return 0;
} else luaL_addchar(buffer, input[0]);
break;
/* might have to be quoted always */
case QP_QUOTED:
qpquote(input[0], buffer);
break;
/* might never have to be quoted */
default:
luaL_addchar(buffer, input[0]);
break;
}
input[0] = input[1]; input[1] = input[2];
size--;
}
return 0;
}
/*-------------------------------------------------------------------------*\
* Deal with the final characters
\*-------------------------------------------------------------------------*/
static size_t qppad(UC *input, size_t size, luaL_Buffer *buffer)
{
size_t i;
for (i = 0; i < size; i++) {
if (qpclass[input[i]] == QP_PLAIN) luaL_addchar(buffer, input[i]);
else qpquote(input[i], buffer);
}
if (size > 0) luaL_addstring(buffer, EQCRLF);
return 0;
}
/*-------------------------------------------------------------------------*\
* Incrementally converts a string to quoted-printable
* A, B = qp(C, D, marker)
* Marker is the text to be used to replace CRLF sequences found in A.
* A is the encoded version of the largest prefix of C .. D that
* can be encoded without doubts.
* B has the remaining bytes of C .. D, *without* encoding.
\*-------------------------------------------------------------------------*/
static int mime_global_qp(lua_State *L)
{
size_t asize = 0, isize = 0;
UC atom[3];
const UC *input = (UC *) luaL_optlstring(L, 1, NULL, &isize);
const UC *last = input + isize;
const char *marker = luaL_optstring(L, 3, CRLF);
luaL_Buffer buffer;
/* end-of-input blackhole */
if (!input) {
lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* make sure we don't confuse buffer stuff with arguments */
lua_settop(L, 3);
/* process first part of input */
luaL_buffinit(L, &buffer);
while (input < last)
asize = qpencode(*input++, atom, asize, marker, &buffer);
input = (UC *) luaL_optlstring(L, 2, NULL, &isize);
/* if second part is nil, we are done */
if (!input) {
asize = qppad(atom, asize, &buffer);
luaL_pushresult(&buffer);
if (!(*lua_tostring(L, -1))) lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* otherwise process rest of input */
last = input + isize;
while (input < last)
asize = qpencode(*input++, atom, asize, marker, &buffer);
luaL_pushresult(&buffer);
lua_pushlstring(L, (char *) atom, asize);
return 2;
}
/*-------------------------------------------------------------------------*\
* Accumulate characters until we are sure about how to deal with them.
* Once we are sure, output the to the buffer, in the correct form.
\*-------------------------------------------------------------------------*/
static size_t qpdecode(UC c, UC *input, size_t size, luaL_Buffer *buffer) {
int d;
input[size++] = c;
/* deal with all characters we can deal */
switch (input[0]) {
/* if we have an escape character */
case '=':
if (size < 3) return size;
/* eliminate soft line break */
if (input[1] == '\r' && input[2] == '\n') return 0;
/* decode quoted representation */
c = qpunbase[input[1]]; d = qpunbase[input[2]];
/* if it is an invalid, do not decode */
if (c > 15 || d > 15) luaL_addlstring(buffer, (char *)input, 3);
else luaL_addchar(buffer, (char) ((c << 4) + d));
return 0;
case '\r':
if (size < 2) return size;
if (input[1] == '\n') luaL_addlstring(buffer, (char *)input, 2);
return 0;
default:
if (input[0] == '\t' || (input[0] > 31 && input[0] < 127))
luaL_addchar(buffer, input[0]);
return 0;
}
}
/*-------------------------------------------------------------------------*\
* Incrementally decodes a string in quoted-printable
* A, B = qp(C, D)
* A is the decoded version of the largest prefix of C .. D that
* can be decoded without doubts.
* B has the remaining bytes of C .. D, *without* decoding.
\*-------------------------------------------------------------------------*/
static int mime_global_unqp(lua_State *L)
{
size_t asize = 0, isize = 0;
UC atom[3];
const UC *input = (UC *) luaL_optlstring(L, 1, NULL, &isize);
const UC *last = input + isize;
luaL_Buffer buffer;
/* end-of-input blackhole */
if (!input) {
lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* make sure we don't confuse buffer stuff with arguments */
lua_settop(L, 2);
/* process first part of input */
luaL_buffinit(L, &buffer);
while (input < last)
asize = qpdecode(*input++, atom, asize, &buffer);
input = (UC *) luaL_optlstring(L, 2, NULL, &isize);
/* if second part is nil, we are done */
if (!input) {
luaL_pushresult(&buffer);
if (!(*lua_tostring(L, -1))) lua_pushnil(L);
lua_pushnil(L);
return 2;
}
/* otherwise process rest of input */
last = input + isize;
while (input < last)
asize = qpdecode(*input++, atom, asize, &buffer);
luaL_pushresult(&buffer);
lua_pushlstring(L, (char *) atom, asize);
return 2;
}
/*-------------------------------------------------------------------------*\
* Incrementally breaks a quoted-printed string into lines
* A, n = qpwrp(l, B, length)
* A is a copy of B, broken into lines of at most 'length' bytes.
* 'l' is how many bytes are left for the first line of B.
* 'n' is the number of bytes left in the last line of A.
* There are two complications: lines can't be broken in the middle
* of an encoded =XX, and there might be line breaks already
\*-------------------------------------------------------------------------*/
static int mime_global_qpwrp(lua_State *L)
{
size_t size = 0;
int left = (int) luaL_checknumber(L, 1);
const UC *input = (UC *) luaL_optlstring(L, 2, NULL, &size);
const UC *last = input + size;
int length = (int) luaL_optnumber(L, 3, 76);
luaL_Buffer buffer;
/* end-of-input blackhole */
if (!input) {
if (left < length) lua_pushstring(L, EQCRLF);
else lua_pushnil(L);
lua_pushnumber(L, length);
return 2;
}
/* process all input */
luaL_buffinit(L, &buffer);
while (input < last) {
switch (*input) {
case '\r':
break;
case '\n':
left = length;
luaL_addstring(&buffer, CRLF);
break;
case '=':
if (left <= 3) {
left = length;
luaL_addstring(&buffer, EQCRLF);
}
luaL_addchar(&buffer, *input);
left--;
break;
default:
if (left <= 1) {
left = length;
luaL_addstring(&buffer, EQCRLF);
}
luaL_addchar(&buffer, *input);
left--;
break;
}
input++;
}
luaL_pushresult(&buffer);
lua_pushnumber(L, left);
return 2;
}
/*-------------------------------------------------------------------------*\
* Here is what we do: \n, and \r are considered candidates for line
* break. We issue *one* new line marker if any of them is seen alone, or
* followed by a different one. That is, \n\n and \r\r will issue two
* end of line markers each, but \r\n, \n\r etc will only issue *one*
* marker. This covers Mac OS, Mac OS X, VMS, Unix and DOS, as well as
* probably other more obscure conventions.
*
* c is the current character being processed
* last is the previous character
\*-------------------------------------------------------------------------*/
#define eolcandidate(c) (c == '\r' || c == '\n')
static int eolprocess(int c, int last, const char *marker,
luaL_Buffer *buffer)
{
if (eolcandidate(c)) {
if (eolcandidate(last)) {
if (c == last) luaL_addstring(buffer, marker);
return 0;
} else {
luaL_addstring(buffer, marker);
return c;
}
} else {
luaL_addchar(buffer, (char) c);
return 0;
}
}
/*-------------------------------------------------------------------------*\
* Converts a string to uniform EOL convention.
* A, n = eol(o, B, marker)
* A is the converted version of the largest prefix of B that can be
* converted unambiguously. 'o' is the context returned by the previous
* call. 'n' is the new context.
\*-------------------------------------------------------------------------*/
static int mime_global_eol(lua_State *L)
{
int ctx = luaL_checkint(L, 1);
size_t isize = 0;
const char *input = luaL_optlstring(L, 2, NULL, &isize);
const char *last = input + isize;
const char *marker = luaL_optstring(L, 3, CRLF);
luaL_Buffer buffer;
luaL_buffinit(L, &buffer);
/* end of input blackhole */
if (!input) {
lua_pushnil(L);
lua_pushnumber(L, 0);
return 2;
}
/* process all input */
while (input < last)
ctx = eolprocess(*input++, ctx, marker, &buffer);
luaL_pushresult(&buffer);
lua_pushnumber(L, ctx);
return 2;
}
/*-------------------------------------------------------------------------*\
* Takes one byte and stuff it if needed.
\*-------------------------------------------------------------------------*/
static size_t dot(int c, size_t state, luaL_Buffer *buffer)
{
luaL_addchar(buffer, (char) c);
switch (c) {
case '\r':
return 1;
case '\n':
return (state == 1)? 2: 0;
case '.':
if (state == 2)
luaL_addchar(buffer, '.');
default:
return 0;
}
}
/*-------------------------------------------------------------------------*\
* Incrementally applies smtp stuffing to a string
* A, n = dot(l, D)
\*-------------------------------------------------------------------------*/
static int mime_global_dot(lua_State *L)
{
size_t isize = 0, state = (size_t) luaL_checknumber(L, 1);
const char *input = luaL_optlstring(L, 2, NULL, &isize);
const char *last = input + isize;
luaL_Buffer buffer;
/* end-of-input blackhole */
if (!input) {
lua_pushnil(L);
lua_pushnumber(L, 2);
return 2;
}
/* process all input */
luaL_buffinit(L, &buffer);
while (input < last)
state = dot(*input++, state, &buffer);
luaL_pushresult(&buffer);
lua_pushnumber(L, (lua_Number) state);
return 2;
}