/** Append data to the currently open log entry.
*
* This function requires that the log_lock is acquired by the caller.
*/
static void log_append(const uint8_t *data, size_t len)
{
/* Cap the length so that the entry entirely fits into the buffer */
if (len > LOG_LENGTH - log_current_len) {
len = LOG_LENGTH - log_current_len;
}
if (len == 0)
return;
size_t log_free = LOG_LENGTH - log_used - log_current_len;
/* Discard older entries to make space, if necessary */
while (len > log_free) {
size_t entry_len;
log_copy_from((uint8_t *) &entry_len, log_start, sizeof(size_t));
log_start = (log_start + entry_len) % LOG_LENGTH;
log_used -= entry_len;
log_free += entry_len;
next_for_uspace -= entry_len;
}
size_t pos = (log_current_start + log_current_len) % LOG_LENGTH;
log_copy_to(data, pos, len);
log_current_len += len;
}
/** Control of the log from uspace
*
*/
sysarg_t sys_klog(sysarg_t operation, void *buf, size_t size,
sysarg_t level)
{
char *data;
int rc;
if (size > PAGE_SIZE)
return (sysarg_t) ELIMIT;
switch (operation) {
case KLOG_WRITE:
data = (char *) malloc(size + 1, 0);
if (!data)
return (sysarg_t) ENOMEM;
rc = copy_from_uspace(data, buf, size);
if (rc) {
free(data);
return (sysarg_t) rc;
}
data[size] = 0;
if (level >= LVL_LIMIT)
level = LVL_NOTE;
log(LF_USPACE, level, "%s", data);
free(data);
return EOK;
case KLOG_READ:
data = (char *) malloc(size, 0);
if (!data)
return (sysarg_t) ENOMEM;
size_t entry_len = 0;
size_t copied = 0;
rc = EOK;
spinlock_lock(&log_lock);
while (next_for_uspace < log_used) {
size_t pos = (log_start + next_for_uspace) % LOG_LENGTH;
log_copy_from((uint8_t *) &entry_len, pos, sizeof(size_t));
if (entry_len > PAGE_SIZE) {
/*
* Since we limit data transfer
* to uspace to a maximum of PAGE_SIZE
* bytes, skip any entries larger
* than this limit to prevent
* userspace being stuck trying to
* read them.
*/
next_for_uspace += entry_len;
continue;
}
if (size < copied + entry_len) {
if (copied == 0)
rc = EOVERFLOW;
break;
}
log_copy_from((uint8_t *) (data + copied), pos, entry_len);
copied += entry_len;
next_for_uspace += entry_len;
}
spinlock_unlock(&log_lock);
if (rc != EOK) {
free(data);
return (sysarg_t) rc;
}
rc = copy_to_uspace(buf, data, size);
free(data);
if (rc != EOK)
return (sysarg_t) rc;
return copied;
default:
return (sysarg_t) ENOTSUP;
}
}
