static void
readFromChannel(TConn * const connectionP,
bool * const eofP,
const char ** const errorP) {
/*----------------------------------------------------------------------------
Read some data from the channel of Connection *connectionP.
Iff there is none available to read, return *eofP == true.
-----------------------------------------------------------------------------*/
uint32_t bytesRead;
bool readError;
ChannelRead(connectionP->channelP,
connectionP->buffer.b + connectionP->buffersize,
bufferSpace(connectionP) - 1,
&bytesRead, &readError);
if (readError)
xmlrpc_asprintf(errorP, "Error reading from channel");
else {
*errorP = NULL;
if (bytesRead > 0) {
*eofP = FALSE;
traceChannelRead(connectionP, bytesRead);
connectionP->inbytes += bytesRead;
connectionP->buffersize += bytesRead;
connectionP->buffer.t[connectionP->buffersize] = '\0';
} else
*eofP = TRUE;
}
}
/*
* read specified amount of bytes from given desc/offset to buffer
* return amount of read bytes or negative error code if call failed
*/
static int32_t ZVMReadHandle(struct NaClApp *nap,
int ch, char *buffer, int32_t size, int64_t offset)
{
struct ChannelDesc *channel;
int64_t tail;
char *sys_buffer;
assert(nap != NULL);
assert(nap->manifest != NULL);
assert(nap->manifest->channels != NULL);
/* check the channel number */
if(ch < 0 || ch >= nap->manifest->channels->len)
{
ZLOGS(LOG_DEBUG, "channel_id=%d, buffer=%p, size=%d, offset=%ld",
ch, buffer, size, offset);
return -EINVAL;
}
channel = CH_CH(nap->manifest, ch);
ZLOGS(LOG_INSANE, "channel %s, buffer=%p, size=%d, offset=%ld",
channel->alias, buffer, size, offset);
/* check buffer and convert address */
if(CheckRAMAccess(nap, (uintptr_t)buffer, size, PROT_WRITE) == -1) return -EINVAL;
sys_buffer = (char*)NaClUserToSys(nap, (uintptr_t)buffer);
/* ignore user offset for sequential access read */
if(CH_SEQ_READABLE(channel))
offset = channel->getpos;
else
/* prevent reading beyond the end of the random access channels */
size = MIN(channel->size - offset, size);
/* check arguments sanity */
if(size == 0) return 0; /* success. user has read 0 bytes */
if(size < 0) return -EFAULT;
if(offset < 0) return -EINVAL;
/* check for eof */
if(channel->eof) return 0;
/* check limits */
if(channel->counters[GetsLimit] >= channel->limits[GetsLimit])
return -EDQUOT;
if(CH_RND_READABLE(channel))
if(offset >= channel->limits[PutSizeLimit] - channel->counters[PutSizeLimit]
+ channel->size) return -EINVAL;
/* calculate i/o leftovers */
tail = channel->limits[GetSizeLimit] - channel->counters[GetSizeLimit];
if(size > tail) size = tail;
if(size < 1) return -EDQUOT;
/* read data */
return ChannelRead(channel, sys_buffer, (size_t)size, (off_t)offset);
}
