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Copy pathmultipartdecoder.c
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454 lines (420 loc) · 14.3 KB
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#include "multipartdecoder.h"
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <fsdyn/bytearray.h>
#include <fsdyn/charstr.h>
#include <fsdyn/fsalloc.h>
#include <fstrace.h>
#include "async_version.h"
typedef enum {
MULTIPARTDECODER_READING_DASH_BOUNDARY,
MULTIPARTDECODER_AFTER_DASH_BOUNDARY,
MULTIPARTDECODER_AFTER_FIRST_CR,
MULTIPARTDECODER_READING_PART,
MULTIPARTDECODER_AFTER_DELIMITER,
MULTIPARTDECODER_READING_PADDING,
MULTIPARTDECODER_AFTER_CR,
MULTIPARTDECODER_AFTER_HYPHEN,
MULTIPARTDECODER_SKIPPING,
MULTIPARTDECODER_EOF,
MULTIPARTDECODER_ERRORED,
MULTIPARTDECODER_CLOSED
} multipartdecoder_state_t;
struct multipartdecoder {
async_t *async;
uint64_t uid;
int pending_errno;
bytestream_1 source;
action_1 callback;
multipartdecoder_state_t state;
char *delimiter;
size_t delimiter_cursor;
byte_array_t *output_buffer;
size_t output_cursor;
char buffer[1024];
size_t low, high;
};
FSTRACE_DECL(ASYNC_MULTIPARTDECODER_CREATE,
"UID=%64u PTR=%p ASYNC=%p SOURCE=%p BOUNDARY=%s");
multipartdecoder_t *multipart_decode(async_t *async, bytestream_1 source,
const char *boundary, bool first_part)
{
multipartdecoder_t *decoder = fsalloc(sizeof *decoder);
decoder->async = async;
decoder->uid = fstrace_get_unique_id();
decoder->pending_errno = 0;
FSTRACE(ASYNC_MULTIPARTDECODER_CREATE, decoder->uid, decoder, async,
source.obj, boundary);
decoder->source = source;
decoder->callback = NULL_ACTION_1;
decoder->delimiter = charstr_printf("\r\n--%s", boundary);
if (first_part) {
decoder->state = MULTIPARTDECODER_READING_DASH_BOUNDARY;
/* we match the dash-boundary using the delimiter starting at
* offset 2, since delimiter := CRLF dash-boundary
*/
decoder->delimiter_cursor = 2;
} else {
decoder->state = MULTIPARTDECODER_READING_PART;
decoder->delimiter_cursor = 0;
}
decoder->output_buffer = make_byte_array(strlen(decoder->delimiter));
decoder->output_cursor = 0;
decoder->low = decoder->high = 0;
return decoder;
}
static const char *trace_state(void *pstate)
{
switch (*(multipartdecoder_state_t *) pstate) {
case MULTIPARTDECODER_READING_DASH_BOUNDARY:
return "MULTIPARTDECODER_READING_DASH_BOUNDARY";
case MULTIPARTDECODER_AFTER_DASH_BOUNDARY:
return "MULTIPARTDECODER_AFTER_DASH_BOUNDARY";
case MULTIPARTDECODER_AFTER_FIRST_CR:
return "MULTIPARTDECODER_AFTER_FIRST_CR";
case MULTIPARTDECODER_READING_PART:
return "MULTIPARTDECODER_READING_PART";
case MULTIPARTDECODER_AFTER_DELIMITER:
return "MULTIPARTDECODER_AFTER_DELIMITER";
case MULTIPARTDECODER_READING_PADDING:
return "MULTIPARTDECODER_READING_PADDING";
case MULTIPARTDECODER_AFTER_CR:
return "MULTIPARTDECODER_AFTER_CR";
case MULTIPARTDECODER_AFTER_HYPHEN:
return "MULTIPARTDECODER_AFTER_HYPHEN";
case MULTIPARTDECODER_SKIPPING:
return "MULTIPARTDECODER_SKIPPING";
case MULTIPARTDECODER_EOF:
return "MULTIPARTDECODER_EOF";
case MULTIPARTDECODER_ERRORED:
return "MULTIPARTDECODER_ERRORED";
case MULTIPARTDECODER_CLOSED:
return "MULTIPARTDECODER_CLOSED";
default:
return "?";
}
}
FSTRACE_DECL(ASYNC_MULTIPARTDECODER_SET_STATE, "UID=%64u OLD=%I NEW=%I");
static void set_decoder_state(multipartdecoder_t *decoder,
multipartdecoder_state_t state)
{
FSTRACE(ASYNC_MULTIPARTDECODER_SET_STATE, decoder->uid, trace_state,
&decoder->state, trace_state, &state);
decoder->state = state;
}
static ssize_t skip_data(multipartdecoder_t *decoder)
{
ssize_t count = bytestream_1_read(decoder->source, decoder->buffer,
sizeof decoder->buffer);
if (count < 0)
return -1;
if (!count) {
set_decoder_state(decoder, MULTIPARTDECODER_EOF);
return 0;
}
async_execute(decoder->async, decoder->callback);
errno = EAGAIN;
return -1;
}
/*
* RFC 2046 grammar
*
* bcharsnospace := DIGIT / ALPHA / "'" / "(" / ")" /
* "+" / "_" / "," / "-" / "." /
* "/" / ":" / "=" / "?"
*
* bchars := bcharsnospace / " "
*
* boundary := 0*69<bchars> bcharsnospace
*
* dash-boundary := "--" boundary
*
* delimiter := CRLF dash-boundary
*
* transport-padding := *LWSP-char
*
* encapsulation := delimiter transport-padding
* CRLF body-part
*
* close-delimiter := delimiter "--"
*
* discard-text := *(*text CRLF) *text
*
* preamble := discard-text
*
* epilogue := discard-text
*
* multipart-body := [preamble CRLF]
* dash-boundary transport-padding CRLF
* body-part *encapsulation
* close-delimiter transport-padding
* [CRLF epilogue]
*/
static void read_symbol(multipartdecoder_t *decoder, char c)
{
switch (decoder->state) {
case MULTIPARTDECODER_READING_DASH_BOUNDARY:
if (c == decoder->delimiter[decoder->delimiter_cursor]) {
decoder->delimiter_cursor++;
if (!decoder->delimiter[decoder->delimiter_cursor]) {
decoder->delimiter_cursor = 0;
set_decoder_state(decoder,
MULTIPARTDECODER_AFTER_DASH_BOUNDARY);
}
} else
decoder->delimiter_cursor = 2;
break;
case MULTIPARTDECODER_AFTER_DASH_BOUNDARY:
switch (c) {
case ' ':
case '\t':
break;
case '\r':
set_decoder_state(decoder, MULTIPARTDECODER_AFTER_FIRST_CR);
break;
default:
set_decoder_state(decoder, MULTIPARTDECODER_ERRORED);
break;
}
break;
case MULTIPARTDECODER_AFTER_FIRST_CR:
switch (c) {
case '\n':
set_decoder_state(decoder, MULTIPARTDECODER_READING_PART);
break;
default:
set_decoder_state(decoder, MULTIPARTDECODER_ERRORED);
break;
}
break;
case MULTIPARTDECODER_READING_PART:
if (c == decoder->delimiter[decoder->delimiter_cursor]) {
decoder->delimiter_cursor++;
if (!decoder->delimiter[decoder->delimiter_cursor]) {
decoder->delimiter_cursor = 0;
set_decoder_state(decoder,
MULTIPARTDECODER_AFTER_DELIMITER);
}
} else {
/* We rely on the fact that no delimiter prefix is
* also a suffix of a (longer) delimiter prefix
* (because CR and LF are not legal in the
* boundary), i.e., we can restart matching the
* delimiter from the first position.
*/
decoder->output_cursor = 0;
byte_array_clear(decoder->output_buffer);
byte_array_append(decoder->output_buffer, decoder->delimiter,
decoder->delimiter_cursor);
decoder->delimiter_cursor = 0;
if (c == decoder->delimiter[0])
decoder->delimiter_cursor++;
else
byte_array_append(decoder->output_buffer, &c, 1);
}
break;
case MULTIPARTDECODER_AFTER_DELIMITER:
switch (c) {
case ' ':
case '\t':
set_decoder_state(decoder,
MULTIPARTDECODER_READING_PADDING);
break;
case '\r':
set_decoder_state(decoder, MULTIPARTDECODER_AFTER_CR);
break;
case '-':
set_decoder_state(decoder, MULTIPARTDECODER_AFTER_HYPHEN);
break;
default:
set_decoder_state(decoder, MULTIPARTDECODER_ERRORED);
break;
}
break;
case MULTIPARTDECODER_READING_PADDING:
switch (c) {
case ' ':
case '\t':
break;
case '\r':
set_decoder_state(decoder, MULTIPARTDECODER_AFTER_CR);
break;
default:
set_decoder_state(decoder, MULTIPARTDECODER_ERRORED);
break;
}
break;
case MULTIPARTDECODER_AFTER_CR:
switch (c) {
case '\n':
set_decoder_state(decoder, MULTIPARTDECODER_EOF);
break;
default:
set_decoder_state(decoder, MULTIPARTDECODER_ERRORED);
break;
}
break;
case MULTIPARTDECODER_AFTER_HYPHEN:
switch (c) {
case '-':
set_decoder_state(decoder, MULTIPARTDECODER_SKIPPING);
break;
default:
set_decoder_state(decoder, MULTIPARTDECODER_ERRORED);
break;
}
break;
default:
assert(false);
}
}
FSTRACE_DECL(ASYNC_MULTIPARTDECODER_INPUT_DUMP, "UID=%64u DATA=%A");
static ssize_t do_read(multipartdecoder_t *decoder, void *buf, size_t size)
{
switch (decoder->state) {
case MULTIPARTDECODER_SKIPPING:
return skip_data(decoder);
case MULTIPARTDECODER_EOF:
errno = 0;
return 0;
case MULTIPARTDECODER_ERRORED:
errno = EPROTO;
return -1;
case MULTIPARTDECODER_CLOSED:
errno = EBADF;
return -1;
default:
break;
}
if (decoder->pending_errno) {
errno = decoder->pending_errno;
decoder->pending_errno = 0;
return -1;
}
size_t cursor = 0;
char *ptr = buf;
while (cursor < size) {
if (decoder->low >= decoder->high) {
ssize_t count = bytestream_1_read(decoder->source, decoder->buffer,
sizeof decoder->buffer);
if (count < 0) {
if (!cursor)
return -1;
if (errno != EAGAIN)
decoder->pending_errno = errno;
break;
}
if (!count) {
errno = EPROTO;
return -1;
}
FSTRACE(ASYNC_MULTIPARTDECODER_INPUT_DUMP, decoder->uid,
decoder->buffer, count);
decoder->low = 0;
decoder->high = count;
}
if (decoder->output_cursor < byte_array_size(decoder->output_buffer)) {
const char *data = byte_array_data(decoder->output_buffer);
ptr[cursor++] = data[decoder->output_cursor++];
} else {
char c = decoder->buffer[decoder->low++];
read_symbol(decoder, c);
switch (decoder->state) {
case MULTIPARTDECODER_SKIPPING:
decoder->low = decoder->high = 0;
if (cursor)
return cursor;
return skip_data(decoder);
case MULTIPARTDECODER_EOF:
return cursor;
case MULTIPARTDECODER_ERRORED:
errno = EPROTO;
return -1;
default:
break;
}
}
}
return cursor;
}
FSTRACE_DECL(ASYNC_MULTIPARTDECODER_READ, "UID=%64u WANT=%z GOT=%z ERRNO=%e");
FSTRACE_DECL(ASYNC_MULTIPARTDECODER_READ_DUMP, "UID=%64u DATA=%A");
ssize_t multipartdecoder_read(multipartdecoder_t *decoder, void *buf,
size_t size)
{
ssize_t count = do_read(decoder, buf, size);
FSTRACE(ASYNC_MULTIPARTDECODER_READ, decoder->uid, size, count);
FSTRACE(ASYNC_MULTIPARTDECODER_READ_DUMP, decoder->uid, buf, count);
return count;
}
static ssize_t _read(void *obj, void *buf, size_t count)
{
return multipartdecoder_read(obj, buf, count);
}
void multipartdecoder_close(multipartdecoder_t *decoder)
{
assert(decoder->state != MULTIPARTDECODER_CLOSED);
decoder->callback = NULL_ACTION_1;
destroy_byte_array(decoder->output_buffer);
fsfree(decoder->delimiter);
async_wound(decoder->async, decoder);
set_decoder_state(decoder, MULTIPARTDECODER_CLOSED);
}
static void _close(void *obj)
{
multipartdecoder_close(obj);
}
void multipartdecoder_register_callback(multipartdecoder_t *decoder,
action_1 action)
{
decoder->callback = action;
bytestream_1_register_callback(decoder->source, action);
}
static void _register_callback(void *obj, action_1 action)
{
multipartdecoder_register_callback(obj, action);
}
void multipartdecoder_unregister_callback(multipartdecoder_t *decoder)
{
multipartdecoder_register_callback(decoder, NULL_ACTION_1);
}
static void _unregister_callback(void *obj)
{
multipartdecoder_unregister_callback(obj);
}
static ssize_t _remaining(void *obj)
{
errno = ENOTSUP;
return -1;
}
size_t multipartdecoder_leftover_size(multipartdecoder_t *decoder)
{
return decoder->high - decoder->low;
}
static ssize_t _leftover_size(void *obj)
{
return multipartdecoder_leftover_size(obj);
}
void *multipartdecoder_leftover_bytes(multipartdecoder_t *decoder)
{
return decoder->buffer + decoder->low;
}
static void *_leftover_bytes(void *obj)
{
return multipartdecoder_leftover_bytes(obj);
}
static const struct bytestream_2_vt multipartdecoder_vt = {
.read = _read,
.close = _close,
.register_callback = _register_callback,
.unregister_callback = _unregister_callback,
.remaining = _remaining,
.leftover_size = _leftover_size,
.leftover_bytes = _leftover_bytes,
};
bytestream_2 multipartdecoder_as_bytestream_2(multipartdecoder_t *decoder)
{
return (bytestream_2) { decoder, &multipartdecoder_vt };
}