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diff --git a/c_src/fasthtml_worker.c b/c_src/fasthtml_worker.c
index 0030b2b..ad2baa2 100644
--- a/c_src/fasthtml_worker.c
+++ b/c_src/fasthtml_worker.c
@@ -1,537 +1,537 @@
// SPDX-FileCopyrightText: 2019-2022 Pleroma Authors <https://pleroma.social>
// SPDX-License-Identifier: LGPL-2.1-only
#include <stdlib.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <ctype.h>
#ifndef _REENTRANT
#define _REENTRANT /* For some reason __erl_errno is undefined unless _REENTRANT is defined */
#endif
#include "ei.h"
#ifndef OTP_22_OR_NEWER
# include "erl_interface.h"
#endif
#define HEADER_SIZE 4
#include <lexbor/html/html.h>
#include "tstack.h"
#ifdef __GNUC__
# define AFP(x, y) __attribute__((format (printf, x, y)))
#else
# define AFP(x, y)
#endif
#ifdef __GNUC__
# define NORETURN __attribute__((noreturn))
#else
# define NORETURN
#endif
typedef struct _state_t {
ei_x_buff buffer;
} state_t;
typedef enum parse_flags_e {
FLAG_HTML_ATOMS = 1 << 0,
FLAG_NIL_SELF_CLOSING = 1 << 1,
FLAG_COMMENT_TUPLE3 = 1 << 2
} parse_flags_t;
char* read_packet(int *len);
static void handle_send(state_t * state);
static void err_term(ei_x_buff * response, const char * error_atom);
static parse_flags_t decode_parse_flags(state_t * state, int arity);
static void decode(state_t * state, ei_x_buff * response, lxb_html_document_t *document, bool fragment, lxb_dom_element_t *context_element, lxb_char_t * bin_data, size_t bin_size, parse_flags_t parse_flags);
static void build_tree(ei_x_buff * response, lxb_dom_node_t* tree, parse_flags_t parse_flags);
static void prepare_node_attrs(ei_x_buff * response, lxb_dom_node_t* node);
static inline char * lowercase(char * c);
static void panic(const char *fmt, ...) AFP(1, 2);
static void panic(const char *fmt, ...) {
char buf[4096];
va_list va;
va_start (va, fmt);
vsnprintf (buf, sizeof buf, fmt, va);
va_end (va);
fprintf (stderr, "fast_html worker: error: %s\n", buf);
exit (EXIT_FAILURE);
}
int main(int argc, const char *argv[]) {
state_t* state = calloc (1, sizeof(state_t));
#ifdef OTP_22_OR_NEWER
// initialize erlang client library
ei_init ();
#else
erl_init (NULL, -1);
#endif
ei_x_new (&state->buffer);
fflush (stdout);
while (true) {
int len;
char* buf = read_packet(&len);
ei_x_free(&state->buffer);
state->buffer.index = 0;
state->buffer.buff = buf;
state->buffer.buffsz = len;
handle_send (state);
}
// shutdown: free all state
ei_x_free (&state->buffer);
free (state);
return EXIT_SUCCESS;
}
/*
* Reads a packet from Erlang. The packet must be a standard {packet, 2}
* packet. This function aborts if any error is detected (including EOF).
*
* Returns: The number of bytes in the packet.
*/
char *read_packet(int *len)
{
char* io_buf = NULL; /* Buffer for file i/o. */
unsigned char header[HEADER_SIZE];
uint32_t packet_length; /* Length of current packet. */
uint32_t bytes_read;
uint32_t total_bytes_read;
/*
* Read the packet header.
*/
total_bytes_read = read(STDIN_FILENO, header, HEADER_SIZE);
if (total_bytes_read == 0) {
exit(0);
}
if (total_bytes_read != HEADER_SIZE) {
panic("Failed to read packet header, read: %d\n", total_bytes_read);
}
/*
* Get the length of this packet.
*/
packet_length = 0;
for (int i = 0; i < HEADER_SIZE; i++)
packet_length = (packet_length << 8) | header[i];
*len=packet_length;
if ((io_buf = (char *) malloc(packet_length)) == NULL) {
panic("insufficient memory for i/o buffer of size %d\n", packet_length);
}
/*
* Read the packet itself.
*/
total_bytes_read = 0;
while((bytes_read = read(STDIN_FILENO, (io_buf + total_bytes_read), (packet_length - total_bytes_read))))
total_bytes_read += bytes_read;
if (total_bytes_read != packet_length) {
free(io_buf);
panic("couldn't read packet of length %d, read: %d\r\n",
packet_length, total_bytes_read);
}
return io_buf;
}
// handle ERL_SEND message type.
// we expect a tuple with arity of 3 or 4 in state->buffer.
// we expect the first argument to be an atom (`decode` or `decode_fragment`),
// the second argument to be the HTML payload, and the
// third argument to be the argument list.
// In case of `decode_fragment`, the fourth argument should be
// the context tag name.
// any other message: respond with an {error, unknown_call} tuple.
static void handle_send (state_t * state)
{
// response holds our response, prepare it
ei_x_buff response;
ei_x_new (&response);
// check the protocol version, if it's unsupported, panic
int version;
if (ei_decode_version (state->buffer.buff, &state->buffer.index, &version) < 0)
panic ("malformed message - bad version (%d).", version);
// decode the tuple header
int arity;
if (ei_decode_tuple_header (state->buffer.buff, &state->buffer.index, &arity) < 0)
{
err_term (&response, "badmatch");
goto out;
}
char atom[MAXATOMLEN];
if (ei_decode_atom (state->buffer.buff, &state->buffer.index, atom) < 0)
{
err_term (&response, "badmatch");
goto out;
}
bool fragment = false;
if (strcmp (atom, "decode"))
{
if (strcmp (atom, "decode_fragment")) {
err_term (&response, "unknown_call");
goto out;
} else if (arity != 4) {
err_term (&response, "badmatch");
goto out;
} else {
fragment = true;
}
} else if (arity != 3) {
err_term (&response, "badmatch");
goto out;
}
// the next argument should be a binary, allocate it dynamically.
int bin_type, bin_size;
if (ei_get_type (state->buffer.buff, &state->buffer.index, &bin_type, &bin_size) < 0)
panic ("failed to decode binary size in message");
// verify the type
if (bin_type != ERL_BINARY_EXT)
{
err_term (&response, "badmatch");
goto out;
}
// decode the binary
char * bin_data = calloc (1, bin_size + 1);
if (ei_decode_binary (state->buffer.buff, &state->buffer.index, bin_data, NULL) < 0)
panic ("failed to decode binary in message");
// next should be the options list
if (ei_decode_list_header (state->buffer.buff, &state->buffer.index, &arity) < 0)
panic ("failed to decode options list header in message");
parse_flags_t parse_flags = decode_parse_flags (state, arity);
// Lists with items always have an empty list as their tail
if (arity != 0)
if (ei_decode_list_header (state->buffer.buff, &state->buffer.index, &arity) < 0)
panic ("failed to decode empty list header after option list in message");
lxb_html_document_t *document = lxb_html_document_create();
lxb_dom_element_t *context_element = NULL;
// if we are parsing a fragment, context tag name should come next
if (fragment) {
int context_bin_type, context_bin_size;
if (ei_get_type (state->buffer.buff, &state->buffer.index, &context_bin_type, &context_bin_size) < 0)
panic ("failed to decode binary size in message");
// verify the type
if (context_bin_type != ERL_BINARY_EXT)
{
err_term (&response, "badmatch");
goto out;
}
// decode the binary
char* context_bin_data = calloc (1, context_bin_size + 1);
if (ei_decode_binary (state->buffer.buff, &state->buffer.index, context_bin_data, NULL) < 0)
panic ("failed to decode context binary in message");
context_element = lxb_dom_document_create_element(&document->dom_document, (lxb_char_t*) context_bin_data, context_bin_size, NULL);
free (context_bin_data);
}
if (context_element && lxb_dom_element_tag_id(context_element) >= LXB_TAG__LAST_ENTRY) {
err_term (&response, "unknown_context_tag");
} else {
decode (state, &response, document, fragment, context_element, (lxb_char_t *) bin_data, bin_size, parse_flags);
}
lxb_html_document_destroy(document);
free (bin_data);
out: ;
// send response
unsigned char header[HEADER_SIZE];
uint32_t size = (uint32_t) response.index;
for (int i = HEADER_SIZE-1; i != -1; i--) {
header[i] = (unsigned char) size & 0xFF;
size = size >> 8;
}
- write(STDOUT_FILENO, header, sizeof(header));
- write(STDOUT_FILENO, response.buff, response.index);
+ if(write(STDOUT_FILENO, header, sizeof(header)) <0) panic ("Failed to write header to stdout");
+ if(write(STDOUT_FILENO, response.buff, response.index) <0) panic ("Failed to write response to stdout");
// free response
ei_x_free (&response);
return;
}
static void err_term (ei_x_buff * response, const char * error_atom)
{
response->index = 0;
ei_x_encode_version (response);
ei_x_encode_tuple_header (response, 2);
ei_x_encode_atom (response, "error");
ei_x_encode_atom (response, error_atom);
}
static parse_flags_t decode_parse_flags (state_t * state, int arity)
{
parse_flags_t parse_flags = 0;
for (int i = 0; i < arity; i++)
{
char atom[MAXATOMLEN];
if (ei_decode_atom (state->buffer.buff, &state->buffer.index, atom) < 0)
continue;
if (! strcmp ("html_atoms", atom))
parse_flags |= FLAG_HTML_ATOMS;
else if (! strcmp ("nil_self_closing", atom))
parse_flags |= FLAG_NIL_SELF_CLOSING;
else if (! strcmp ("comment_tuple3", atom))
parse_flags |= FLAG_COMMENT_TUPLE3;
}
return parse_flags;
}
static void decode(state_t * state, ei_x_buff * response, lxb_html_document_t *document, bool fragment, lxb_dom_element_t *context_element, lxb_char_t * bin_data, size_t bin_size, parse_flags_t parse_flags)
{
// parse tree
lxb_status_t status;
lxb_dom_node_t *node;
if (fragment) {
node = lxb_html_document_parse_fragment(document, context_element, bin_data, bin_size);
status = (node == NULL)? LXB_STATUS_ERROR : LXB_STATUS_OK;
} else {
status = lxb_html_document_parse(document, bin_data, bin_size);
node = lxb_dom_interface_node(document);
}
if (status != LXB_STATUS_OK)
{
err_term (response, "parse_failed");
return;
}
// build tree
build_tree (response, node, parse_flags);
}
// a tag is sent as a tuple:
// - a string or atom for the tag name
// - an attribute list
// - a children list
// in this function, we prepare the atom and complete attribute list
static void prepare_tag_header (ei_x_buff * response, const char * tag_string, lxb_dom_node_t* node, parse_flags_t parse_flags)
{
lxb_tag_id_t tag_id = lxb_dom_node_tag_id(node);
ei_x_encode_tuple_header (response, 3);
if (! (parse_flags & FLAG_HTML_ATOMS) || (tag_id == LXB_TAG__UNDEF || tag_id >= LXB_TAG__LAST_ENTRY))
ei_x_encode_binary (response, tag_string, strlen (tag_string));
else
ei_x_encode_atom (response, tag_string);
prepare_node_attrs (response, node);
}
// prepare an attribute node
static void prepare_node_attrs(ei_x_buff * response, lxb_dom_node_t* node)
{
lxb_dom_attr_t *attr;
for (attr = lxb_dom_element_first_attribute(lxb_dom_interface_element(node)); attr != NULL; attr = lxb_dom_element_next_attribute(attr))
{
size_t attr_name_len;
char *attr_name = (char*) lxb_dom_attr_qualified_name(attr, &attr_name_len);
size_t attr_value_len;
const char *attr_value = (char*) lxb_dom_attr_value(attr, &attr_value_len);
/* guard against poisoned attribute nodes */
if (! attr_name_len)
continue;
ei_x_encode_list_header (response, 1);
ei_x_encode_tuple_header (response, 2);
ei_x_encode_binary (response, attr_name, attr_name_len);
ei_x_encode_binary (response, attr_value, attr_value_len);
}
ei_x_encode_empty_list (response);
}
// dump a comment node
static void prepare_comment (ei_x_buff * response, const char * node_comment, size_t comment_len, parse_flags_t parse_flags)
{
ei_x_encode_tuple_header (response, parse_flags & FLAG_COMMENT_TUPLE3 ? 3 : 2);
ei_x_encode_atom (response, "comment");
if (parse_flags & FLAG_COMMENT_TUPLE3)
ei_x_encode_list_header (response, 0);
ei_x_encode_binary (response, node_comment, comment_len);
}
#ifdef DEBUG_LIST_MANIP
#define EMIT_LIST_HDR \
printf ("list hdr for node %p\n", current_node); \
fflush (stdout); \
ei_x_encode_list_header (response, 1)
#define EMIT_EMPTY_LIST_HDR \
printf ("list empty for node %p\n", current_node); \
fflush (stdout); \
ei_x_encode_list_header (response, 0)
#define EMIT_LIST_TAIL \
printf ("list tail for node %p\n", current_node); \
fflush (stdout); \
ei_x_encode_empty_list (response)
#else
#define EMIT_LIST_HDR ei_x_encode_list_header (response, 1)
#define EMIT_EMPTY_LIST_HDR ei_x_encode_list_header (response, 0)
#define EMIT_LIST_TAIL ei_x_encode_empty_list (response)
#endif
static void build_tree (ei_x_buff * response, lxb_dom_node_t* node, parse_flags_t parse_flags)
{
tstack stack;
tstack_init (&stack, 30);
tstack_push (&stack, node);
lxb_dom_node_t* current_node = node->first_child;
// ok we're going to send an actual response so start encoding it
response->index = 0;
ei_x_encode_version (response);
ei_x_encode_tuple_header(response, 2);
ei_x_encode_atom(response, "ok");
if (current_node == NULL) {
EMIT_EMPTY_LIST_HDR;
EMIT_LIST_TAIL;
}
while (current_node != NULL)
{
if (current_node->type == LXB_DOM_NODE_TYPE_TEXT)
{
size_t text_len;
const char * node_text = (char*) lxb_dom_node_text_content(current_node, &text_len);
EMIT_LIST_HDR;
ei_x_encode_binary (response, node_text, text_len);
}
else if (current_node->type == LXB_DOM_NODE_TYPE_COMMENT)
{
size_t comment_len;
const char* node_comment = (char*) lxb_dom_node_text_content(current_node, &comment_len);
EMIT_LIST_HDR;
prepare_comment(response, node_comment, comment_len, parse_flags);
}
else if(current_node->type == LXB_DOM_NODE_TYPE_ELEMENT)
{
// get name of tag
size_t tag_name_len;
const char *tag_name = (char*) lxb_dom_element_qualified_name(lxb_dom_interface_element(current_node), &tag_name_len);
EMIT_LIST_HDR;
prepare_tag_header (response, tag_name, current_node, parse_flags);
if (current_node->first_child)
{
tstack_push (&stack, current_node);
current_node = current_node->first_child;
continue;
}
else
{
if (parse_flags & FLAG_NIL_SELF_CLOSING && lxb_html_tag_is_void(lxb_dom_node_tag_id(current_node))) {
#ifdef DEBUG_LIST_MANIP
printf ("self-closing tag %s emit nil?\n", tag_string); fflush (stdout);
#endif
ei_x_encode_atom (response, "nil");
}
else
{
EMIT_EMPTY_LIST_HDR;
}
}
}
if (current_node->next)
current_node = current_node->next;
else
{
while (! current_node->next && stack.used != 0)
{
EMIT_LIST_TAIL;
current_node = tstack_pop (&stack);
}
if (current_node->next)
current_node = current_node->next;
}
// are we at root?
if (current_node == node)
break;
}
tstack_free (&stack);
}
static inline char * lowercase(char* c)
{
char * p = c;
while (*p)
{
*p = tolower ((unsigned char) *p);
p++;
}
return c;
}

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