/*===========================================================================*
* subread *
*===========================================================================*/
static int
subread(struct logdevice *log, size_t size, endpoint_t endpt,
cp_grant_id_t grant)
{
size_t offset, count;
char *buf;
int r;
for (offset = 0; log->log_size > 0 && offset < size; offset += count) {
count = size - offset;
if (count > log->log_size)
count = log->log_size;
if (log->log_read + count > LOG_SIZE)
count = LOG_SIZE - log->log_read;
buf = log->log_buffer + log->log_read;
if((r=sys_safecopyto(endpt, grant, offset, (vir_bytes)buf,
count)) != OK)
return r;
LOGINC(log->log_read, count);
log->log_size -= count;
}
return offset;
}
/*===========================================================================*
* subread *
*===========================================================================*/
PRIVATE int
subread(struct logdevice *log, int count, endpoint_t endpt,
cp_grant_id_t grant, size_t offset)
{
char *buf;
int r;
if (count > log->log_size)
count = log->log_size;
if (log->log_read + count > LOG_SIZE)
count = LOG_SIZE - log->log_read;
buf = log->log_buffer + log->log_read;
if((r=sys_safecopyto(endpt, grant, offset,
(vir_bytes)buf, count, D)) != OK)
return r;
LOGINC(log->log_read, count);
log->log_size -= count;
return count;
}
/*===========================================================================*
* subwrite *
*===========================================================================*/
PRIVATE int
subwrite(struct logdevice *log, int count, endpoint_t endpt,
cp_grant_id_t grant, size_t offset, char *localbuf)
{
int d, r;
char *buf;
message m;
if (log->log_write + count > LOG_SIZE)
count = LOG_SIZE - log->log_write;
buf = log->log_buffer + log->log_write;
if(localbuf != NULL) {
memcpy(buf, localbuf, count);
}
else {
if((r=sys_safecopyfrom(endpt, grant, offset,
(vir_bytes)buf, count, D)) != OK)
return r;
}
LOGINC(log->log_write, count);
log->log_size += count;
if(log->log_size > LOG_SIZE) {
int overflow;
overflow = log->log_size - LOG_SIZE;
log->log_size -= overflow;
LOGINC(log->log_read, overflow);
}
if(log->log_size > 0 && log->log_source != NONE &&
!log->log_revive_alerted) {
/* Someone who was suspended on read can now
* be revived.
*/
log->log_status = subread(log, log->log_iosize,
log->log_source, log->log_user_grant,
log->log_user_offset);
m.m_type = DEV_REVIVE;
m.REP_ENDPT = log->log_proc_nr;
m.REP_STATUS = log->log_status;
m.REP_IO_GRANT = log->log_user_grant;
r= send(log->log_source, &m);
if (r != OK)
{
printf("log`subwrite: send to %d failed: %d\n",
log->log_source, r);
}
log->log_source = NONE;
}
if(log->log_size > 0)
log->log_select_ready_ops |= SEL_RD;
if(log->log_size > 0 && log->log_selected &&
!(log->log_select_alerted)) {
/* Someone(s) who was/were select()ing can now
* be awoken. If there was a blocking read (above),
* this can only happen if the blocking read didn't
* swallow all the data (log_size > 0).
*/
if(log->log_selected & SEL_RD) {
d= log-logdevices;
m.m_type = DEV_SEL_REPL2;
m.DEV_SEL_OPS = log->log_select_ready_ops;
m.DEV_MINOR = d;
#if LOG_DEBUG
printf("select sending DEV_SEL_REPL2\n");
#endif
r= send(log->log_select_proc, &m);
if (r != OK)
{
printf(
"log`subwrite: send to %d failed: %d\n",
log->log_select_proc, r);
}
log->log_selected &= ~log->log_select_ready_ops;
}
}
return count;
}
/*===========================================================================*
* subwrite *
*===========================================================================*/
static int
subwrite(struct logdevice *log, size_t size, endpoint_t endpt,
cp_grant_id_t grant, char *localbuf)
{
size_t count, offset;
int overflow, r, result;
devminor_t minor;
char *buf;
message m;
/* With a sufficiently large input size, we might wrap around the ring buffer
* multiple times.
*/
result = 0;
for (offset = 0; offset < size; offset += count) {
count = size - offset;
if (log->log_write + count > LOG_SIZE)
count = LOG_SIZE - log->log_write;
buf = log->log_buffer + log->log_write;
if(localbuf != NULL) {
memcpy(buf, localbuf, count);
localbuf += count;
}
else {
if((r=sys_safecopyfrom(endpt, grant, offset,
(vir_bytes)buf, count)) != OK) {
/* return any partial success upon error */
result = (offset > 0) ? (int)offset : r;
break;
}
}
LOGINC(log->log_write, count);
log->log_size += count;
if(log->log_size > LOG_SIZE) {
overflow = log->log_size - LOG_SIZE;
log->log_size -= overflow;
LOGINC(log->log_read, overflow);
}
result += (int)count;
}
if (log->log_size > 0 && log->log_source != NONE) {
/* Someone who was suspended on read can now be revived. */
r = subread(log, log->log_iosize, log->log_source, log->log_grant);
chardriver_reply_task(log->log_source, log->log_id, r);
log->log_source = NONE;
}
if (log->log_size > 0 && (log->log_selected & CDEV_OP_RD)) {
/* Someone(s) who was/were select()ing can now be awoken. If there was
* a blocking read (above), this can only happen if the blocking read
* didn't swallow all the data (log_size > 0).
*/
minor = log-logdevices;
#if LOG_DEBUG
printf("select sending CDEV_SEL2_REPLY\n");
#endif
chardriver_reply_select(log->log_select_proc, minor, CDEV_OP_RD);
log->log_selected &= ~CDEV_OP_RD;
}
return result;
}