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multipart_parser.c
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/* Based on node-formidable by Felix Geisendörfer
* Igor Afonov - [email protected] - 2012
* MIT License - http://www.opensource.org/licenses/mit-license.php
*/
#include "multipart_parser.h"
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#ifdef DEBUG_MULTIPART
#include <ctype.h>
#define multipart_log(format, ...) \
do { \
fprintf(stderr, "[MULTIPART_PARSER] line %d: " format "\n", __LINE__, __VA_ARGS__); \
} while (0)
#define multipart_log_c(format) \
do { \
if (isprint(c)) { \
multipart_log("parsing '%c' " format, c); \
} else { \
multipart_log("parsing '\\x%0.2x' " format, c); \
} \
} while (0)
#else
#define multipart_log(format, ...)
#define multipart_log_c(format, ...)
#endif
#define NOTIFY_CB(FOR, r) \
do { \
if (p->settings->on_##FOR) { \
if ((ret = p->settings->on_##FOR(p)) == MPPE_PAUSED) { \
return r; \
} else if (ret != MPPE_OK) { \
return MPPE_ERROR; \
} \
} \
} while (0)
#define EMIT_DATA_CB(FOR, r, ptr, len) \
do { \
if (p->settings->on_##FOR) { \
if ((ret = p->settings->on_##FOR(p, ptr, len)) == MPPE_PAUSED) { \
return r; \
} else if (ret != MPPE_OK) { \
return MPPE_ERROR; \
} \
} \
} while (0)
#define ERROR_OUT(reason) \
do { \
p->error_unexpected = c; \
p->error_i = i; \
p->error_reason = reason; \
return MPPE_ERROR; \
} while (0)
#define ERROR_EXPECT(reason, ch) \
do { \
p->error_expected = ch; \
if (ch == LF) { \
multipart_log("expecting LF at %zu, but it's \\x%.2x", i, c); \
} else if (ch == CR) { \
multipart_log("expecting CR at %zu, but it's \\x%.2x", i, c); \
} else { \
multipart_log("expecting '%c' at %zu, but it's \\x%.2x", ch, i, c); \
} \
ERROR_OUT(reason); \
} while (0)
#define LF 10
#define CR 13
enum state {
s_uninitialized = 0,
s_start,
s_start_boundary,
s_header_field_start,
s_header_field,
s_headers_almost_done,
s_header_value_start,
s_header_value,
s_header_value_almost_done,
s_part_data_start,
s_part_data,
s_part_data_almost_boundary,
s_part_data_boundary,
s_part_data_almost_end,
s_part_data_end,
s_part_data_final_hyphen,
s_end
};
multipart_parser *multipart_parser_init(const char *boundary,
size_t boundary_length,
const multipart_parser_settings *settings) {
multipart_parser *p = calloc(sizeof(multipart_parser) + boundary_length + boundary_length + 9 + 4, sizeof(char));
memcpy(p->boundary, "--", 2);
memcpy(p->boundary + 2, boundary, boundary_length);
p->boundary[2 + boundary_length] = 0;
p->boundary_length = boundary_length + 2;
p->index = 0;
p->state = s_start;
p->error_i = 0;
p->error_unexpected = 0;
p->error_expected = 0;
p->error_reason = MPPE_OK;
p->state = s_start;
p->settings = settings;
return p;
}
void multipart_parser_free(multipart_parser *p) {
free(p);
}
int multipart_parser_error_msg(multipart_parser *p, char *buf, size_t len) {
int ret;
switch (p->error_reason) {
case MPPE_OK:
return 0;
case MPPE_PAUSED:
return snprintf(buf, len, "parser paused");
case MPPE_UNKNOWN:
return snprintf(buf, len, "parser unknown");
default:
return snprintf(buf, len, "parser abort");
case MPPE_BOUNDARY_END_NO_CRLF:
ret = snprintf(buf, len, "no CRLF at first boundary end: ");
break;
case MPPE_BAD_START_BOUNDARY:
ret = snprintf(buf, len, "first boundary mismatching: ");
break;
case MPPE_INVALID_HEADER_FIELD_CHAR:
ret = snprintf(buf, len, "invalid char in header field: ");
break;
case MPPE_INVALID_HEADER_VALUE_CHAR:
ret = snprintf(buf, len, "invalid char in header value: ");
break;
case MPPE_BAD_PART_END:
ret = snprintf(buf, len, "no next part or final hyphen: expecting CR or '-' ");
break;
case MPPE_END_BOUNDARY_NO_DASH:
ret = snprintf(buf, len, "bad final hyphen: ");
break;
}
if (ret < 0) {
return 0;
}
if ((size_t) ret >= len) {
return ret;
}
switch (p->error_expected) {
case '\0':
break;
case CR:
ret += snprintf(buf + ret, len - ret, "expecting CR ");
break;
case LF:
ret += snprintf(buf + ret, len - ret, "expecting LF ");
break;
default:
ret += snprintf(buf + ret, len - ret, "expecting '%c' ", p->error_expected);
break;
}
if (ret < 0) {
return 0;
}
if ((size_t) ret >= len) {
return ret;
}
if (isprint(p->error_unexpected)) {
ret += snprintf(buf + ret, len - ret, "at %zu, but it is '%c'", p->error_i, p->error_unexpected);
} else {
ret += snprintf(buf + ret, len - ret, "at %zu, but it is '\\x%.2x'", p->error_i, p->error_unexpected);
}
return ret;
}
ssize_t multipart_parser_execute(multipart_parser *p, const char *buf, size_t len) {
size_t i = 0;
size_t mark = 0;
size_t mark_end = 0;
char c, cl;
int is_last = 0;
int ret;
while (i < len) {
c = buf[i];
is_last = (i == (len - 1));
switch (p->state) {
case s_start:
multipart_log_c("s_start");
p->index = 0;
p->state = s_start_boundary;
/* fallthrough */
/* no break */
case s_start_boundary:
multipart_log_c("s_start_boundary");
if (p->index == p->boundary_length) {
// https://github.com/swoole/swoole-src/issues/5168
if (c == '-') {
p->state = s_part_data_final_hyphen;
} else if (c != CR) {
ERROR_EXPECT(MPPE_BOUNDARY_END_NO_CRLF, CR);
}
p->index++;
break;
} else if (p->index == (size_t)(p->boundary_length + 1)) {
if (c != LF) {
ERROR_EXPECT(MPPE_BOUNDARY_END_NO_CRLF, LF);
}
p->index = 0;
p->state = s_header_field_start;
NOTIFY_CB(part_data_begin, i + 1);
break;
}
if (c != p->boundary[p->index]) {
ERROR_EXPECT(MPPE_BAD_START_BOUNDARY, p->boundary[p->index]);
}
p->index++;
break;
case s_header_field_start:
multipart_log_c("s_header_field_start");
mark = i;
p->state = s_header_field;
/* fallthrough */
/* no break */
case s_header_field:
multipart_log_c("s_header_field");
if (c == CR) {
p->state = s_headers_almost_done;
break;
}
if (c == '-') {
if (is_last) {
EMIT_DATA_CB(header_field, i + 1, buf + mark, i - mark + 1);
}
break;
}
if (c == ':') {
p->state = s_header_value_start;
EMIT_DATA_CB(header_field, i + 1, buf + mark, i - mark);
break;
}
cl = c | 0x20;
if (cl < 'a' || cl > 'z') {
multipart_log_c("invalid character in header field");
p->error_unexpected = c;
ERROR_OUT(MPPE_INVALID_HEADER_FIELD_CHAR);
}
if (is_last) {
EMIT_DATA_CB(header_field, i + 1, buf + mark, i - mark + 1);
}
break;
case s_headers_almost_done:
multipart_log_c("s_headers_almost_done");
if (c != LF) {
ERROR_EXPECT(MPPE_INVALID_HEADER_VALUE_CHAR, LF);
}
p->state = s_part_data_start;
break;
case s_header_value_start:
multipart_log_c("s_header_value_start");
if (c == ' ') {
break;
}
mark = i;
p->state = s_header_value;
/* fallthrough */
/* no break */
case s_header_value:
multipart_log_c("s_header_value");
if (c == CR) {
p->state = s_header_value_almost_done;
EMIT_DATA_CB(header_value, i + 1, buf + mark, i - mark);
} else if (is_last) {
ERROR_EXPECT(MPPE_HEADER_VALUE_INCOMPLETE, CR);
}
break;
case s_header_value_almost_done:
multipart_log_c("s_header_value_almost_done");
if (c != LF) {
ERROR_EXPECT(MPPE_INVALID_HEADER_VALUE_CHAR, LF);
}
p->state = s_header_field_start;
break;
case s_part_data_start:
multipart_log_c("s_part_data_start");
mark = i;
p->state = s_part_data;
NOTIFY_CB(headers_complete, i);
/* fallthrough */
/* no break */
case s_part_data:
data_rollback:
multipart_log_c("s_part_data");
mark_end = i + 1;
if (c == CR) {
if (mark_end - mark - 1 > 0) {
EMIT_DATA_CB(part_data, i + 1, buf + mark, mark_end - mark - 1);
}
mark = i;
p->state = s_part_data_almost_boundary;
break;
}
if (is_last) {
EMIT_DATA_CB(part_data, i + 1, buf + mark, mark_end - mark);
}
break;
case s_part_data_almost_boundary:
multipart_log_c("s_part_data_almost_boundary");
if (c != LF) {
EMIT_DATA_CB(part_data, i + 1, "\r", 1);
p->state = s_part_data;
mark = i;
goto data_rollback;
} else {
p->state = s_part_data_boundary;
p->index = 0;
break;
}
case s_part_data_boundary:
multipart_log_c("s_part_data_boundary");
if (p->boundary[p->index] != c) {
EMIT_DATA_CB(part_data, i + 1, "\r\n", 2);
if (p->index > 0) {
EMIT_DATA_CB(part_data, i + 1, p->boundary, p->index);
}
mark = i;
p->state = s_part_data;
goto data_rollback;
} else {
p->index++;
if (p->index == p->boundary_length) {
p->state = s_part_data_almost_end;
}
break;
}
case s_part_data_almost_end:
multipart_log_c("s_part_data_almost_end");
if (c == '-') {
p->state = s_part_data_final_hyphen;
NOTIFY_CB(part_data_end, i + 1);
break;
}
if (c == CR) {
p->state = s_part_data_end;
NOTIFY_CB(part_data_end, i + 1);
break;
}
// should be end or another part
multipart_log("expecting '-' or CR at %zu but it's \\x%0.2x", i, c);
ERROR_OUT(MPPE_BAD_PART_END);
case s_part_data_final_hyphen:
multipart_log_c("s_part_data_final_hyphen");
if (c == '-') {
p->state = s_end;
NOTIFY_CB(body_end, i);
break;
}
// should be -
ERROR_EXPECT(MPPE_END_BOUNDARY_NO_DASH, '-');
case s_part_data_end:
multipart_log_c("s_part_data_end");
if (c == LF) {
p->state = s_header_field_start;
NOTIFY_CB(part_data_begin, i + 1);
break;
}
// should be -
ERROR_EXPECT(MPPE_END_BOUNDARY_NO_DASH, '-');
case s_end:
multipart_log_c("s_end");
break;
default:
multipart_log_c("Multipart parser unrecoverable error");
ERROR_OUT(MPPE_UNKNOWN);
}
++i;
}
return i;
}