minix/drivers/log/log.c

489 lines
14 KiB
C

/* This file contains a driver for:
* /dev/klog - system log device
*
* Changes:
* 21 July 2005 - Support for diagnostic messages (Jorrit N. Herder)
* 7 July 2005 - Created (Ben Gras)
*/
#include "log.h"
#include <sys/time.h>
#include <sys/select.h>
#include "../../kernel/const.h"
#include "../../kernel/type.h"
#define LOG_DEBUG 0 /* enable/ disable debugging */
#define NR_DEVS 1 /* number of minor devices */
#define MINOR_KLOG 0 /* /dev/klog */
#define LOGINC(n, i) do { (n) = (((n) + (i)) % LOG_SIZE); } while(0)
PUBLIC struct logdevice logdevices[NR_DEVS];
PRIVATE struct device log_geom[NR_DEVS]; /* base and size of devices */
PRIVATE int log_device = -1; /* current device */
FORWARD _PROTOTYPE( char *log_name, (void) );
FORWARD _PROTOTYPE( struct device *log_prepare, (int device) );
FORWARD _PROTOTYPE( int log_transfer, (int proc_nr, int opcode, off_t position,
iovec_t *iov, unsigned nr_req) );
FORWARD _PROTOTYPE( int log_do_open, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( int log_cancel, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( int log_select, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( int log_other, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( void log_geometry, (struct partition *entry) );
FORWARD _PROTOTYPE( void log_reply, (int code, int replyee, int proc, int status) );
FORWARD _PROTOTYPE( int subread, (struct logdevice *log, int count, int proc_nr, vir_bytes user_vir) );
/* Entry points to this driver. */
PRIVATE struct driver log_dtab = {
log_name, /* current device's name */
log_do_open, /* open or mount */
do_nop, /* nothing on a close */
do_nop, /* ioctl nop */
log_prepare, /* prepare for I/O on a given minor device */
log_transfer, /* do the I/O */
nop_cleanup, /* no need to clean up */
log_geometry, /* geometry */
nop_signal, /* no need to clean up on shutdown */
nop_alarm, /* no alarm */
log_cancel, /* CANCEL request */
log_select, /* DEV_SELECT request */
log_other /* Unrecognized messages */
};
extern int device_caller;
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC void main(void)
{
int i;
for(i = 0; i < NR_DEVS; i++) {
log_geom[i].dv_size = cvul64(LOG_SIZE);
log_geom[i].dv_base = cvul64((long)logdevices[i].log_buffer);
logdevices[i].log_size = logdevices[i].log_read =
logdevices[i].log_write =
logdevices[i].log_select_alerted =
logdevices[i].log_selected =
logdevices[i].log_select_ready_ops = 0;
logdevices[i].log_proc_nr = 0;
logdevices[i].log_revive_alerted = 0;
}
driver_task(&log_dtab);
}
/*===========================================================================*
* log_name *
*===========================================================================*/
PRIVATE char *log_name()
{
/* Return a name for the current device. */
static char name[] = "log";
return name;
}
/*===========================================================================*
* log_prepare *
*===========================================================================*/
PRIVATE struct device *log_prepare(device)
int device;
{
/* Prepare for I/O on a device: check if the minor device number is ok. */
if (device < 0 || device >= NR_DEVS) return(NIL_DEV);
log_device = device;
return(&log_geom[device]);
}
/*===========================================================================*
* subwrite *
*===========================================================================*/
PRIVATE int
subwrite(struct logdevice *log, int count, int proc_nr, vir_bytes user_vir)
{
char *buf;
int r;
if (log->log_write + count > LOG_SIZE)
count = LOG_SIZE - log->log_write;
buf = log->log_buffer + log->log_write;
if(proc_nr == SELF) {
memcpy(buf, (char *) user_vir, count);
}
else {
if((r=sys_vircopy(proc_nr,D,user_vir, SELF,D,(int)buf, count)) != 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_proc_nr && !log->log_revive_alerted) {
/* Someone who was suspended on read can now
* be revived.
*/
log->log_status = subread(log, log->log_iosize,
log->log_proc_nr, log->log_user_vir);
printf("alert for revive %d..\n", log->log_source);
notify(log->log_source);
printf("alert for revive done..\n");
log->log_revive_alerted = 1;
}
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) {
notify(log->log_select_proc);
log->log_select_alerted = 1;
#if LOG_DEBUG
printf("log notified %d\n", log->log_select_proc);
#endif
}
}
return count;
}
/*===========================================================================*
* log_append *
*===========================================================================*/
PUBLIC void
log_append(char *buf, int count)
{
int w = 0, skip = 0;
if(count < 1) return;
if(count > LOG_SIZE) skip = count - LOG_SIZE;
count -= skip;
buf += skip;
w = subwrite(&logdevices[0], count, SELF, (vir_bytes) buf);
if(w > 0 && w < count)
subwrite(&logdevices[0], count-w, SELF, (vir_bytes) buf+w);
return;
}
/*===========================================================================*
* subread *
*===========================================================================*/
PRIVATE int
subread(struct logdevice *log, int count, int proc_nr, vir_bytes user_vir)
{
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_vircopy(SELF,D,(int)buf,proc_nr,D,user_vir, count)) != OK)
return r;
LOGINC(log->log_read, count);
log->log_size -= count;
return count;
}
/*===========================================================================*
* log_transfer *
*===========================================================================*/
PRIVATE int log_transfer(proc_nr, opcode, position, iov, nr_req)
int proc_nr; /* process doing the request */
int opcode; /* DEV_GATHER or DEV_SCATTER */
off_t position; /* offset on device to read or write */
iovec_t *iov; /* pointer to read or write request vector */
unsigned nr_req; /* length of request vector */
{
/* Read or write one the driver's minor devices. */
unsigned count;
vir_bytes user_vir;
struct device *dv;
unsigned long dv_size;
int s, accumulated_read = 0;
struct logdevice *log;
if(log_device < 0 || log_device >= NR_DEVS)
return EIO;
/* Get minor device number and check for /dev/null. */
dv = &log_geom[log_device];
dv_size = cv64ul(dv->dv_size);
log = &logdevices[log_device];
while (nr_req > 0) {
char *buf;
/* How much to transfer and where to / from. */
count = iov->iov_size;
user_vir = iov->iov_addr;
switch (log_device) {
case MINOR_KLOG:
if (opcode == DEV_GATHER) {
if (log->log_proc_nr || count < 1) {
/* There's already someone hanging to read, or
* no real I/O requested.
*/
return(OK);
}
if (!log->log_size) {
if(accumulated_read)
return OK;
/* No data available; let caller block. */
log->log_proc_nr = proc_nr;
log->log_iosize = count;
log->log_user_vir = user_vir;
log->log_revive_alerted = 0;
/* Device_caller is a global in drivers library. */
log->log_source = device_caller;
#if LOG_DEBUG
printf("blocked %d (%d)\n",
log->log_source, log->log_proc_nr);
#endif
return(SUSPEND);
}
count = subread(log, count, proc_nr, user_vir);
if(count < 0) {
return count;
}
accumulated_read += count;
} else {
count = subwrite(log, count, proc_nr, user_vir);
if(count < 0)
return count;
}
break;
/* Unknown (illegal) minor device. */
default:
return(EINVAL);
}
/* Book the number of bytes transferred. */
iov->iov_addr += count;
if ((iov->iov_size -= count) == 0) { iov++; nr_req--; }
}
return(OK);
}
/*===========================================================================*
* log_reply *
*===========================================================================*/
PRIVATE void log_reply(code, replyee, process, status)
int code; /* TASK_REPLY or REVIVE */
int replyee; /* destination for message (normally FS) */
int process; /* which user requested the printing */
int status; /* number of chars printed or error code */
{
message mess;
mess.m_type = code;
mess.REP_STATUS = status;
mess.REP_PROC_NR = process;
send(replyee, &mess);
}
/*============================================================================*
* log_do_open *
*============================================================================*/
PRIVATE int log_do_open(dp, m_ptr)
struct driver *dp;
message *m_ptr;
{
if (log_prepare(m_ptr->DEVICE) == NIL_DEV) return(ENXIO);
return(OK);
}
/*============================================================================*
* log_geometry *
*============================================================================*/
PRIVATE void log_geometry(entry)
struct partition *entry;
{
/* take a page from the fake memory device geometry */
entry->heads = 64;
entry->sectors = 32;
entry->cylinders = div64u(log_geom[log_device].dv_size, SECTOR_SIZE) /
(entry->heads * entry->sectors);
}
/*============================================================================*
* log_cancel *
*============================================================================*/
PRIVATE int log_cancel(dp, m_ptr)
struct driver *dp;
message *m_ptr;
{
int d;
d = m_ptr->TTY_LINE;
if(d < 0 || d >= NR_DEVS)
return EINVAL;
logdevices[d].log_proc_nr = 0;
logdevices[d].log_revive_alerted = 0;
return(OK);
}
/*============================================================================*
* do_status *
*============================================================================*/
PRIVATE void do_status(message *m_ptr)
{
int d, nr = 0;
message m;
/* Caller has requested pending status information, which currently
* can be pending available select()s, or REVIVE events. One message
* is returned for every event, or DEV_NO_STATUS if no (more) events
* are to be returned.
*/
for(d = 0; d < NR_DEVS; d++) {
/* Check for revive callback. */
if(logdevices[d].log_proc_nr && logdevices[d].log_revive_alerted
&& logdevices[d].log_source == m_ptr->m_source) {
m.m_type = DEV_REVIVE;
m.REP_PROC_NR = logdevices[d].log_proc_nr;
m.REP_STATUS = logdevices[d].log_status;
send(m_ptr->m_source, &m);
logdevices[d].log_proc_nr = 0;
logdevices[d].log_revive_alerted = 0;
#if LOG_DEBUG
printf("revived %d with %d bytes\n",
m.REP_PROC_NR, m.REP_STATUS);
#endif
return;
}
/* Check for select callback. */
if(logdevices[d].log_selected && logdevices[d].log_select_proc == m_ptr->m_source
&& logdevices[d].log_select_alerted) {
m.m_type = DEV_IO_READY;
m.DEV_SEL_OPS = logdevices[d].log_select_ready_ops;
m.DEV_MINOR = d;
#if LOG_DEBUG
printf("select sending sent\n");
#endif
send(m_ptr->m_source, &m);
logdevices[d].log_selected &= ~logdevices[d].log_select_ready_ops;
logdevices[d].log_select_alerted = 0;
#if LOG_DEBUG
printf("select send sent\n");
#endif
return;
}
}
/* No event found. */
m.m_type = DEV_NO_STATUS;
send(m_ptr->m_source, &m);
return;
}
/*============================================================================*
* log_other *
*============================================================================*/
PRIVATE int log_other(dp, m_ptr)
struct driver *dp;
message *m_ptr;
{
int r;
/* This function gets messages that the generic driver doesn't
* understand.
*/
switch(m_ptr->m_type) {
case DIAGNOSTICS: {
r = do_diagnostics(m_ptr);
break;
}
case SYS_EVENT: {
sigset_t sigset = m_ptr->NOTIFY_ARG;
if (sigismember(&sigset, SIGKMESS)) {
do_new_kmess(m_ptr);
}
r = EDONTREPLY;
break;
}
case DEV_STATUS: {
do_status(m_ptr);
r = EDONTREPLY;
break;
}
default:
r = EINVAL;
break;
}
return r;
}
/*============================================================================*
* log_select *
*============================================================================*/
PRIVATE int log_select(dp, m_ptr)
struct driver *dp;
message *m_ptr;
{
int d, ready_ops = 0, ops = 0;
d = m_ptr->TTY_LINE;
if(d < 0 || d >= NR_DEVS) {
#if LOG_DEBUG
printf("line %d? EINVAL\n", d);
#endif
return EINVAL;
}
ops = m_ptr->PROC_NR & (SEL_RD|SEL_WR|SEL_ERR);
/* Read blocks when there is no log. */
if((m_ptr->PROC_NR & SEL_RD) && logdevices[d].log_size > 0) {
#if LOG_DEBUG
printf("log can read; size %d\n", logdevices[d].log_size);
#endif
ready_ops |= SEL_RD; /* writes never block */
}
/* Write never blocks. */
if(m_ptr->PROC_NR & SEL_WR) ready_ops |= SEL_WR;
/* Enable select calback if no operations were
* ready to go, but operations were requested,
* and notify was enabled.
*/
if((m_ptr->PROC_NR & SEL_NOTIFY) && ops && !ready_ops) {
logdevices[d].log_selected |= ops;
logdevices[d].log_select_proc = m_ptr->m_source;
#if LOG_DEBUG
printf("log setting selector.\n");
#endif
}
#if LOG_DEBUG
printf("log returning ops %d\n", ready_ops);
#endif
return(ready_ops);
}