0,0 → 1,72 |
/* |
* unpacks a http "chunked" transfer into a raw data stream. |
* this file is part of the pkgnet tool from the SvarDOS project. |
* |
* Copyright (C) 2021 Mateusz Viste |
*/ |
|
#include <stdlib.h> /* atol() */ |
#include <string.h> |
|
#include "unchunk.h" |
|
|
/* transforms a http CHUNKED stream into actual data, returns the amount of |
* raw data to read or -1 on error. st MUST be zeroed before first call. */ |
int unchunk(unsigned char *buff, int bufflen, struct unchunk_state *st) { |
int hdrstart, hdrend; |
|
/* if chunk header was being in progress, try to decode it now */ |
if (st->bytesleft == -1) { |
int partial_hdr_len = strlen(st->partial_hdr); |
/* locate header terminator, if available */ |
for (hdrend = 0; (hdrend < bufflen) && (buff[hdrend] != '\n'); hdrend++); |
if (partial_hdr_len + hdrend > 15) return(-1); /* error: chunk header too long */ |
|
/* copy header to buffer */ |
memcpy(st->partial_hdr + partial_hdr_len, buff, hdrend); |
st->partial_hdr[partial_hdr_len + hdrend] = 0; |
|
/* quit if header still no complete */ |
if (hdrend >= bufflen) return(0); |
|
/* good, got whole header */ |
bufflen -= hdrend + 1; |
memmove(buff, buff + hdrend + 1, bufflen); |
st->bytesleft = strtol(st->partial_hdr, NULL, 16); |
} |
|
AGAIN: |
|
if (bufflen <= st->bytesleft) { |
st->bytesleft -= bufflen; |
return(bufflen); |
} |
|
/* else bufflen > bytesleft */ |
|
/* skip trailing \r\n after chunk */ |
for (hdrstart = st->bytesleft; hdrstart < bufflen; hdrstart++) if ((buff[hdrstart] != '\r') && (buff[hdrstart] != '\n')) break; |
/* skip chunk size (look for its \n terminator) */ |
for (hdrend = hdrstart; (hdrend < bufflen) && (buff[hdrend] != '\n'); hdrend++); |
|
if (hdrend < bufflen) { /* full header found */ |
long newchunklen; |
/* read the header length */ |
newchunklen = strtol((char *)buff + hdrstart, NULL, 16); |
/* move data over header to get a contiguous block of data */ |
memmove(buff + st->bytesleft, buff + hdrend + 1, bufflen - (hdrend + 1)); |
bufflen -= (hdrend + 1 - st->bytesleft); |
/* update bytesleft */ |
st->bytesleft += newchunklen; |
/* loop again */ |
goto AGAIN; |
} else { /* partial header */ |
if ((bufflen - st->bytesleft) > 15) return(-1); /* error: chunk header appears to be longer than 15 characters */ |
memset(st->partial_hdr, 0, sizeof(st->partial_hdr)); |
memcpy(st->partial_hdr, buff + st->bytesleft, bufflen - st->bytesleft); |
bufflen -= (bufflen - st->bytesleft); |
st->bytesleft = -1; /* "header in progress" */ |
return(bufflen); |
} |
} |