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mime: implement encoders.

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curl_mime_encoder() is operational and documented.
curl tool -F option is extended with ";encoder=".
curl tool --libcurl option generates calls to curl_mime_encoder().
New encoder tests 648 & 649.
Test 1404 extended with an encoder specification.
This commit is contained in:
Patrick Monnerat 2017-09-05 17:11:59 +01:00
parent 3bbe894fd2
commit 63ef436ea1
12 changed files with 809 additions and 45 deletions
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467
lib/mime.c
View file

@ -55,6 +55,73 @@
#define READ_ERROR ((size_t) -1)
/* Encoders. */
static size_t encoder_nop_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part);
static curl_off_t encoder_nop_size(struct Curl_mimepart *part);
static size_t encoder_7bit_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part);
static size_t encoder_base64_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part);
static curl_off_t encoder_base64_size(struct Curl_mimepart *part);
static size_t encoder_qp_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part);
static curl_off_t encoder_qp_size(struct Curl_mimepart *part);
static const mime_encoder encoders[] = {
{"binary", encoder_nop_read, encoder_nop_size},
{"8bit", encoder_nop_read, encoder_nop_size},
{"7bit", encoder_7bit_read, encoder_nop_size},
{"base64", encoder_base64_read, encoder_base64_size},
{"quoted-printable", encoder_qp_read, encoder_qp_size},
{ZERO_NULL, ZERO_NULL, ZERO_NULL}
};
/* Base64 encoding table */
static const char base64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/* Quoted-printable character class table.
*
* We cannot rely on ctype functions since quoted-printable input data
* is assumed to be ascii-compatible, even on non-ascii platforms. */
#define QP_OK 1 /* Can be represented by itself. */
#define QP_SP 2 /* Space or tab. */
#define QP_CR 3 /* Carriage return. */
#define QP_LF 4 /* Line-feed. */
static const unsigned char qp_class[] = {
0, 0, 0, 0, 0, 0, 0, 0, /* 00 - 07 */
0, QP_SP, QP_LF, 0, 0, QP_CR, 0, 0, /* 08 - 0F */
0, 0, 0, 0, 0, 0, 0, 0, /* 10 - 17 */
0, 0, 0, 0, 0, 0, 0, 0, /* 18 - 1F */
QP_SP, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 20 - 27 */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 28 - 2F */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 30 - 37 */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, 0 , QP_OK, QP_OK, /* 38 - 3F */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 40 - 47 */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 48 - 4F */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 50 - 57 */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 58 - 5F */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 60 - 67 */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 68 - 6F */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, /* 70 - 77 */
QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, QP_OK, 0, /* 78 - 7F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 80 - 8F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 90 - 9F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A0 - AF */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* B0 - BF */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* C0 - CF */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* D0 - DF */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* E0 - EF */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 /* F0 - FF */
};
/* Binary --> hexadecimal ASCII table. */
static const char aschex[] =
"\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x41\x42\x43\x44\x45\x46";
#ifndef __VMS
#define filesize(name, stat_data) (stat_data.st_size)
@ -277,6 +344,279 @@ static char *strippath(const char *fullfile)
return base; /* returns an allocated string or NULL ! */
}
/* Initialize data encoder state. */
static void cleanup_encoder_state(mime_encoder_state *p)
{
p->pos = 0;
p->bufbeg = 0;
p->bufend = 0;
}
/* Dummy encoder. This is used for 8bit and binary content encodings. */
static size_t encoder_nop_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part)
{
mime_encoder_state *st = &part->encstate;
size_t insize = st->bufend - st->bufbeg;
(void) ateof;
if(size > insize)
size = insize;
if(size)
memcpy(buffer, st->buf, size);
st->bufbeg += size;
return size;
}
static curl_off_t encoder_nop_size(struct Curl_mimepart *part)
{
return part->datasize;
}
/* 7bit encoder: the encoder is just a data validity check. */
static size_t encoder_7bit_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part)
{
size_t i;
mime_encoder_state *st = &part->encstate;
size_t cursize = st->bufend - st->bufbeg;
(void) ateof;
if(size > cursize)
size = cursize;
for(cursize = 0; cursize < size; cursize++) {
*buffer = st->buf[st->bufbeg];
if(*buffer++ & 0x80)
return cursize? cursize: READ_ERROR;
st->bufbeg++;
}
return cursize;
}
/* Base64 content encoder. */
static size_t encoder_base64_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part)
{
mime_encoder_state *st = &part->encstate;
size_t cursize = 0;
int i;
char *ptr = buffer;
while(st->bufbeg < st->bufend) {
/* Line full ? */
if(st->pos >= MAX_ENCODED_LINE_LENGTH - 4) {
/* Yes, we need 2 characters for CRLF. */
if(size < 2)
break;
*ptr++ = '\r';
*ptr++ = '\n';
st->pos = 0;
cursize += 2;
size -= 2;
}
/* Be sure there is enough space and input data for a base64 group. */
if(size < 4 || st->bufend - st->bufbeg < 3)
break;
/* Encode three bytes a four characters. */
i = st->buf[st->bufbeg++] & 0xFF;
i = (i << 8) | (st->buf[st->bufbeg++] & 0xFF);
i = (i << 8) | (st->buf[st->bufbeg++] & 0xFF);
*ptr++ = base64[(i >> 18) & 0x3F];
*ptr++ = base64[(i >> 12) & 0x3F];
*ptr++ = base64[(i >> 6) & 0x3F];
*ptr++ = base64[i & 0x3F];
cursize += 4;
st->pos += 4;
size -= 4;
}
/* If at eof, we have to flush the buffered data. */
if(ateof && size >= 4) {
/* Buffered data size can only be 0, 1 or 2. */
ptr[2] = ptr[3] = '=';
i = 0;
switch(st->bufend - st->bufbeg) {
case 2:
i = (st->buf[st->bufbeg + 1] & 0xFF) << 8;
/* FALLTHROUGH */
case 1:
i |= (st->buf[st->bufbeg] & 0xFF) << 16;
ptr[0] = base64[(i >> 18) & 0x3F];
ptr[1] = base64[(i >> 12) & 0x3F];
if(++st->bufbeg != st->bufend) {
ptr[2] = base64[(i >> 6) & 0x3F];
st->bufbeg++;
}
cursize += 4;
st->pos += 4;
break;
}
}
#ifdef CURL_DOES_CONVERSIONS
/* This is now textual data, Convert character codes. */
if(part->easy && cursize) {
CURLcode result = Curl_convert_to_network(part->easy, buffer, cursize);
if(result)
return READ_ERROR;
}
#endif
return cursize;
}
static curl_off_t encoder_base64_size(struct Curl_mimepart *part)
{
curl_off_t size = part->datasize;
if(size <= 0)
return size; /* Unknown size or no data. */
/* Compute base64 character count. */
size = 4 * (1 + (size - 1) / 3);
/* Effective character count must include CRLFs. */
return size + 2 * ((size - 1) / MAX_ENCODED_LINE_LENGTH);
}
/* Quoted-printable lookahead.
*
* Check if a CRLF or end of data is in input buffer at current position + n.
* Return -1 if more data needed, 1 if CRLF or end of data, else 0.
*/
static int qp_lookahead_eol(mime_encoder_state *st, int ateof, size_t n)
{
n += st->bufbeg;
if(n >= st->bufend && ateof)
return 1;
if(n + 2 > st->bufend)
return ateof? 0: -1;
if(qp_class[st->buf[n] & 0xFF] == QP_CR &&
qp_class[st->buf[n + 1] & 0xFF] == QP_LF)
return 1;
return 0;
}
/* Quoted-printable encoder. */
static size_t encoder_qp_read(char *buffer, size_t size, bool ateof,
struct Curl_mimepart *part)
{
mime_encoder_state *st = &part->encstate;
char *ptr = buffer;
size_t cursize = 0;
int i;
size_t len;
size_t consumed;
int softlinebreak;
char buf[4];
/* On all platforms, input is supposed to be ASCII compatible: for this
reason, we use hexadecimal ASCII codes in this function rather than
character constants that can be interpreted as non-ascii on some
platforms. Preserve ASCII encoding on output too. */
while(st->bufbeg < st->bufend) {
len = 1;
consumed = 1;
i = st->buf[st->bufbeg];
buf[0] = (char) i;
buf[1] = aschex[(i >> 4) & 0xF];
buf[2] = aschex[i & 0xF];
switch(qp_class[st->buf[st->bufbeg] & 0xFF]) {
case QP_OK: /* Not a special character. */
break;
case QP_SP: /* Space or tab. */
/* Spacing must be escaped if followed by CRLF. */
switch(qp_lookahead_eol(st, ateof, 1)) {
case -1: /* More input data needed. */
return cursize;
case 0: /* No encoding needed. */
break;
default: /* CRLF after space or tab. */
buf[0] = '\x3D'; /* '=' */
len = 3;
break;
}
break;
case QP_CR: /* Carriage return. */
/* If followed by a line-feed, output the CRLF pair.
Else escape it. */
switch(qp_lookahead_eol(st, ateof, 0)) {
case -1: /* Need more data. */
return cursize;
case 1: /* CRLF found. */
buf[len++] = '\x0A'; /* Append '\n'. */
consumed = 2;
break;
default: /* Not followed by LF: escape. */
buf[0] = '\x3D'; /* '=' */
len = 3;
break;
}
break;
default: /* Character must be escaped. */
buf[0] = '\x3D'; /* '=' */
len = 3;
break;
}
/* Be sure the encoded character fits within maximum line length. */
if(buf[len - 1] != '\x0A') { /* '\n' */
softlinebreak = st->pos + len > MAX_ENCODED_LINE_LENGTH;
if(!softlinebreak && st->pos + len == MAX_ENCODED_LINE_LENGTH) {
/* We may use the current line only if end of data or followed by
a CRLF. */
switch(qp_lookahead_eol(st, ateof, consumed)) {
case -1: /* Need more data. */
return cursize;
break;
case 0: /* Not followed by a CRLF. */
softlinebreak = 1;
break;
}
}
if(softlinebreak) {
strcpy(buf, "\x3D\x0D\x0A"); /* "=\r\n" */
len = 3;
consumed = 0;
}
}
/* If the output buffer would overflow, do not store. */
if(len > size)
break;
/* Append to output buffer. */
memcpy(ptr, buf, len);
cursize += len;
ptr += len;
size -= len;
st->pos += len;
if(buf[len - 1] == '\x0A') /* '\n' */
st->pos = 0;
st->bufbeg += consumed;
}
return cursize;
}
static curl_off_t encoder_qp_size(struct Curl_mimepart *part)
{
/* Determining the size can only be done by reading the data: unless the
data size is 0, we return it as unknown (-1). */
return part->datasize? -1: 0;
}
/* In-memory data callbacks. */
/* Argument is a pointer to the mime part. */
@ -435,6 +775,77 @@ static size_t readback_bytes(struct mime_state *state,
return sz;
}
/* Read a non-encoded part content. */
static size_t read_part_content(struct Curl_mimepart *part,
char *buffer, size_t bufsize)
{
size_t sz = 0;
if(part->readfunc)
sz = part->readfunc(buffer, 1, bufsize, part->arg);
return sz;
}
/* Read and encode part content. */
static size_t read_encoded_part_content(struct Curl_mimepart *part,
char *buffer, size_t bufsize)
{
mime_encoder_state *st = &part->encstate;
size_t cursize = 0;
size_t sz;
bool ateof = FALSE;
while(bufsize) {
if(st->bufbeg < st->bufend || ateof) {
/* Encode buffered data. */
sz = part->encoder->encodefunc(buffer, bufsize, ateof, part);
switch(sz) {
case 0:
if(ateof)
return cursize;
break;
case CURL_READFUNC_ABORT:
case CURL_READFUNC_PAUSE:
case READ_ERROR:
return cursize? cursize: sz;
default:
cursize += sz;
buffer += sz;
bufsize -= sz;
continue;
}
}
/* We need more data in input buffer. */
if(st->bufbeg) {
size_t len = st->bufend - st->bufbeg;
if(len)
memmove(st->buf, st->buf + st->bufbeg, len);
st->bufbeg = 0;
st->bufend = len;
}
if(st->bufend >= sizeof st->buf)
return cursize? cursize: READ_ERROR; /* Buffer full. */
sz = read_part_content(part, st->buf + st->bufend,
sizeof st->buf - st->bufend);
switch(sz) {
case 0:
ateof = TRUE;
break;
case CURL_READFUNC_ABORT:
case CURL_READFUNC_PAUSE:
case READ_ERROR:
return cursize? cursize: sz;
default:
st->bufend += sz;
break;
}
}
return cursize;
}
/* Readback a mime part. */
static size_t readback_part(curl_mimepart *part,
char *buffer, size_t bufsize)
@ -491,11 +902,14 @@ static size_t readback_part(curl_mimepart *part,
convbuf = buffer;
}
#endif
cleanup_encoder_state(&part->encstate);
mimesetstate(&part->state, MIMESTATE_CONTENT, NULL);
break;
case MIMESTATE_CONTENT:
if(part->readfunc)
sz = part->readfunc(buffer, 1, bufsize, part->arg);
if(part->encoder)
sz = read_encoded_part_content(part, buffer, bufsize);
else
sz = read_part_content(part, buffer, bufsize);
switch(sz) {
case 0:
mimesetstate(&part->state, MIMESTATE_END, NULL);
@ -634,6 +1048,7 @@ static int mime_part_rewind(curl_mimepart *part)
if(part->flags & MIME_BODY_ONLY)
targetstate = MIMESTATE_BODY;
cleanup_encoder_state(&part->encstate);
if(part->state.state > targetstate) {
res = CURL_SEEKFUNC_CANTSEEK;
if(part->seekfunc) {
@ -643,6 +1058,9 @@ static int mime_part_rewind(curl_mimepart *part)
case CURL_SEEKFUNC_FAIL:
case CURL_SEEKFUNC_CANTSEEK:
break;
case -1: /* For fseek() error. */
res = CURL_SEEKFUNC_CANTSEEK;
break;
default:
res = CURL_SEEKFUNC_FAIL;
break;
@ -702,6 +1120,8 @@ static void cleanup_part_content(curl_mimepart *part)
part->namedfp = NULL;
part->origin = 0;
part->datasize = (curl_off_t) 0; /* No size yet. */
part->encoder = NULL;
cleanup_encoder_state(&part->encstate);
part->kind = MIMEKIND_NONE;
}
@ -976,15 +1396,22 @@ CURLcode curl_mime_type(curl_mimepart *part, const char *mimetype)
/* Set mime data transfer encoder. */
CURLcode curl_mime_encoder(curl_mimepart *part, const char *encoding)
{
CURLcode result = CURLE_OK;
/* Encoding feature not yet implemented. */
CURLcode result = CURLE_BAD_FUNCTION_ARGUMENT;
const mime_encoder *mep;
if(!part)
return CURLE_BAD_FUNCTION_ARGUMENT;
return result;
if(encoding)
return CURLE_BAD_FUNCTION_ARGUMENT;
part->encoder = NULL;
if(!encoding)
return CURLE_OK; /* Removing current encoder. */
for(mep = encoders; mep->name; mep++)
if(strcasecompare(encoding, mep->name)) {
part->encoder = mep;
result = CURLE_OK;
}
return result;
}
@ -1130,6 +1557,10 @@ curl_off_t Curl_mime_size(curl_mimepart *part)
part->datasize = multipart_size(part->arg);
size = part->datasize;
if(part->encoder)
size = part->encoder->sizefunc(part);
if(size >= 0 && !(part->flags & MIME_BODY_ONLY)) {
/* Compute total part size. */
size += slist_size(part->curlheaders, 2, NULL);
@ -1219,6 +1650,7 @@ CURLcode Curl_mime_prepare_headers(curl_mimepart *part,
curl_mime *mime = NULL;
const char *boundary = NULL;
char *s;
const char *cte = NULL;
CURLcode ret = CURLE_OK;
/* Get rid of previously prepared headers. */
@ -1315,13 +1747,18 @@ CURLcode Curl_mime_prepare_headers(curl_mimepart *part,
}
/* Content-Transfer-Encoding header. */
if(contenttype && strategy == MIMESTRATEGY_MAIL &&
part->kind != MIMEKIND_MULTIPART &&
!search_header(part->userheaders, "Content-Transfer-Encoding")) {
ret = Curl_mime_add_header(&part->curlheaders,
"Content-Transfer-Encoding: 8bit");
if(ret)
return ret;
if(!search_header(part->userheaders, "Content-Transfer-Encoding")) {
if(part->encoder)
cte = part->encoder->name;
else if(contenttype && strategy == MIMESTRATEGY_MAIL &&
part->kind != MIMEKIND_MULTIPART)
cte = "8bit";
if(cte) {
ret = Curl_mime_add_header(&part->curlheaders,
"Content-Transfer-Encoding: %s", cte);
if(ret)
return ret;
}
}
/* If we were reading curl-generated headers, restart with new ones (this

22
lib/mime.h
View file

@ -23,6 +23,8 @@
***************************************************************************/
#define MIME_RAND_BOUNDARY_CHARS 16 /* Nb. of random boundary chars. */
#define MAX_ENCODED_LINE_LENGTH 76 /* Maximum encoded line length. */
#define ENCODING_BUFFER_SIZE 256 /* Encoding temp buffers size. */
/* Part flags. */
#define MIME_USERHEADERS_OWNER (1 << 0)
@ -60,6 +62,22 @@ enum mimestrategy {
MIMESTRATEGY_LAST
};
/* Content transfer encoder. */
typedef struct {
const char * name; /* Encoding name. */
size_t (*encodefunc)(char *buffer, size_t size, bool ateof,
curl_mimepart *part); /* Encoded read. */
curl_off_t (*sizefunc)(curl_mimepart *part); /* Encoded size. */
} mime_encoder;
/* Content transfer encoder state. */
typedef struct {
size_t pos; /* Position on output line. */
size_t bufbeg; /* Next data index in input buffer. */
size_t bufend; /* First unused byte index in input buffer. */
char buf[ENCODING_BUFFER_SIZE]; /* Input buffer. */
} mime_encoder_state;
/* Mime readback state. */
struct mime_state {
enum mimestate state; /* Current state token. */
@ -67,7 +85,7 @@ struct mime_state {
size_t offset; /* State-dependent offset. */
};
/* A mime context. */
/* A mime multipart. */
struct curl_mime_s {
struct Curl_easy *easy; /* The associated easy handle. */
curl_mimepart *parent; /* Parent part. */
@ -99,6 +117,8 @@ struct curl_mimepart_s {
curl_off_t datasize; /* Expected data size. */
unsigned int flags; /* Flags. */
struct mime_state state; /* Current readback state. */
const mime_encoder *encoder; /* Content data encoder. */
mime_encoder_state encstate; /* Data encoder state. */
};