minix/drivers/filter/main.c
Cristiano Giuffrida cb176df60f New RS and new signal handling for system processes.
UPDATING INFO:
20100317:
        /usr/src/etc/system.conf updated to ignore default kernel calls: copy
        it (or merge it) to /etc/system.conf.
        The hello driver (/dev/hello) added to the distribution:
        # cd /usr/src/commands/scripts && make clean install
        # cd /dev && MAKEDEV hello

KERNEL CHANGES:
- Generic signal handling support. The kernel no longer assumes PM as a signal
manager for every process. The signal manager of a given process can now be
specified in its privilege slot. When a signal has to be delivered, the kernel
performs the lookup and forwards the signal to the appropriate signal manager.
PM is the default signal manager for user processes, RS is the default signal
manager for system processes. To enable ptrace()ing for system processes, it
is sufficient to change the default signal manager to PM. This will temporarily
disable crash recovery, though.
- sys_exit() is now split into sys_exit() (i.e. exit() for system processes,
which generates a self-termination signal), and sys_clear() (i.e. used by PM
to ask the kernel to clear a process slot when a process exits).
- Added a new kernel call (i.e. sys_update()) to swap two process slots and
implement live update.

PM CHANGES:
- Posix signal handling is no longer allowed for system processes. System
signals are split into two fixed categories: termination and non-termination
signals. When a non-termination signaled is processed, PM transforms the signal
into an IPC message and delivers the message to the system process. When a
termination signal is processed, PM terminates the process.
- PM no longer assumes itself as the signal manager for system processes. It now
makes sure that every system signal goes through the kernel before being
actually processes. The kernel will then dispatch the signal to the appropriate
signal manager which may or may not be PM.

SYSLIB CHANGES:
- Simplified SEF init and LU callbacks.
- Added additional predefined SEF callbacks to debug crash recovery and
live update.
- Fixed a temporary ack in the SEF init protocol. SEF init reply is now
completely synchronous.
- Added SEF signal event type to provide a uniform interface for system
processes to deal with signals. A sef_cb_signal_handler() callback is
available for system processes to handle every received signal. A
sef_cb_signal_manager() callback is used by signal managers to process
system signals on behalf of the kernel.
- Fixed a few bugs with memory mapping and DS.

VM CHANGES:
- Page faults and memory requests coming from the kernel are now implemented
using signals.
- Added a new VM call to swap two process slots and implement live update.
- The call is used by RS at update time and in turn invokes the kernel call
sys_update().

RS CHANGES:
- RS has been reworked with a better functional decomposition.
- Better kernel call masks. com.h now defines the set of very basic kernel calls
every system service is allowed to use. This makes system.conf simpler and
easier to maintain. In addition, this guarantees a higher level of isolation
for system libraries that use one or more kernel calls internally (e.g. printf).
- RS is the default signal manager for system processes. By default, RS
intercepts every signal delivered to every system process. This makes crash
recovery possible before bringing PM and friends in the loop.
- RS now supports fast rollback when something goes wrong while initializing
the new version during a live update.
- Live update is now implemented by keeping the two versions side-by-side and
swapping the process slots when the old version is ready to update.
- Crash recovery is now implemented by keeping the two versions side-by-side
and cleaning up the old version only when the recovery process is complete.

DS CHANGES:
- Fixed a bug when the process doing ds_publish() or ds_delete() is not known
by DS.
- Fixed the completely broken support for strings. String publishing is now
implemented in the system library and simply wraps publishing of memory ranges.
Ideally, we should adopt a similar approach for other data types as well.
- Test suite fixed.

DRIVER CHANGES:
- The hello driver has been added to the Minix distribution to demonstrate basic
live update and crash recovery functionalities.
- Other drivers have been adapted to conform the new SEF interface.
2010-03-17 01:15:29 +00:00

488 lines
13 KiB
C

/* Filter driver - top layer - block interface */
/* This is a filter driver, which lays above disk driver, and forwards
* messages between disk driver and its callers. The filter can detect
* corrupted data (toggled by USE_CHECKSUM) and recover it (toggled
* by USE_MIRROR). These two functions are independent from each other.
* The mirroring function requires two disks, on separate disk drivers.
*/
#include "inc.h"
#include "optset.h"
#define _POSIX_SOURCE 1
#include <signal.h>
/* Global settings. */
int USE_CHECKSUM = 0; /* enable checksumming */
int USE_MIRROR = 0; /* enable mirroring */
int BAD_SUM_ERROR = 1; /* bad checksums are considered a driver error */
int USE_SUM_LAYOUT = 0; /* use checksumming layout on disk */
int NR_SUM_SEC = 8; /* number of checksums per checksum sector */
int SUM_TYPE = ST_CRC; /* use NIL, XOR, CRC, or MD5 */
int SUM_SIZE = 0; /* size of the stored checksum */
int NR_RETRIES = 3; /* number of times the request will be retried (N) */
int NR_RESTARTS = 3; /* number of times a driver will be restarted (M) */
int DRIVER_TIMEOUT = 5; /* timeout in seconds to declare a driver dead (T) */
int CHUNK_SIZE = 0; /* driver requests will be vectorized at this size */
char MAIN_LABEL[LABEL_SIZE] = ""; /* main disk driver label */
char BACKUP_LABEL[LABEL_SIZE] = ""; /* backup disk driver label */
int MAIN_MINOR = -1; /* main partition minor nr */
int BACKUP_MINOR = -1; /* backup partition minor nr */
PRIVATE struct optset optset_table[] = {
{ "label0", OPT_STRING, MAIN_LABEL, LABEL_SIZE },
{ "label1", OPT_STRING, BACKUP_LABEL, LABEL_SIZE },
{ "minor0", OPT_INT, &MAIN_MINOR, 10 },
{ "minor1", OPT_INT, &BACKUP_MINOR, 10 },
{ "sum_sec", OPT_INT, &NR_SUM_SEC, 10 },
{ "layout", OPT_BOOL, &USE_SUM_LAYOUT, 1 },
{ "nolayout", OPT_BOOL, &USE_SUM_LAYOUT, 0 },
{ "sum", OPT_BOOL, &USE_CHECKSUM, 1 },
{ "nosum", OPT_BOOL, &USE_CHECKSUM, 0 },
{ "mirror", OPT_BOOL, &USE_MIRROR, 1 },
{ "nomirror", OPT_BOOL, &USE_MIRROR, 0 },
{ "nil", OPT_BOOL, &SUM_TYPE, ST_NIL },
{ "xor", OPT_BOOL, &SUM_TYPE, ST_XOR },
{ "crc", OPT_BOOL, &SUM_TYPE, ST_CRC },
{ "md5", OPT_BOOL, &SUM_TYPE, ST_MD5 },
{ "sumerr", OPT_BOOL, &BAD_SUM_ERROR, 1 },
{ "nosumerr", OPT_BOOL, &BAD_SUM_ERROR, 0 },
{ "retries", OPT_INT, &NR_RETRIES, 10 },
{ "N", OPT_INT, &NR_RETRIES, 10 },
{ "restarts", OPT_INT, &NR_RESTARTS, 10 },
{ "M", OPT_INT, &NR_RESTARTS, 10 },
{ "timeout", OPT_INT, &DRIVER_TIMEOUT, 10 },
{ "T", OPT_INT, &DRIVER_TIMEOUT, 10 },
{ "chunk", OPT_INT, &CHUNK_SIZE, 10 },
{ NULL }
};
/* Request message. */
static message m_in;
static endpoint_t who_e; /* m_source */
static endpoint_t proc_e; /* IO_ENDPT */
static cp_grant_id_t grant_id; /* IO_GRANT */
/* Data buffers. */
static char *buf_array, *buffer; /* contiguous buffer */
/* SEF functions and variables. */
FORWARD _PROTOTYPE( void sef_local_startup, (void) );
FORWARD _PROTOTYPE( int sef_cb_init_fresh, (int type, sef_init_info_t *info) );
FORWARD _PROTOTYPE( void sef_cb_signal_handler, (int signo) );
EXTERN int env_argc;
EXTERN char **env_argv;
/*===========================================================================*
* carry *
*===========================================================================*/
static int carry(size_t size, int flag_rw)
{
/* Carry data between caller proc and filter.
*/
if (flag_rw == FLT_WRITE)
return sys_safecopyfrom(proc_e, grant_id, 0,
(vir_bytes) buffer, size, D);
else
return sys_safecopyto(proc_e, grant_id, 0,
(vir_bytes) buffer, size, D);
}
/*===========================================================================*
* vcarry *
*===========================================================================*/
static int vcarry(int grants, iovec_t *iov, int flag_rw, size_t size)
{
/* Carry data between caller proc and filter, through grant-vector.
*/
char *bufp;
int i, r;
size_t bytes;
bufp = buffer;
for(i = 0; i < grants && size > 0; i++) {
bytes = MIN(size, iov[i].iov_size);
if (flag_rw == FLT_WRITE)
r = sys_safecopyfrom(proc_e,
(vir_bytes) iov[i].iov_addr, 0,
(vir_bytes) bufp, bytes, D);
else
r = sys_safecopyto(proc_e,
(vir_bytes) iov[i].iov_addr, 0,
(vir_bytes) bufp, bytes, D);
if(r != OK)
return r;
bufp += bytes;
size -= bytes;
}
return OK;
}
/*===========================================================================*
* do_rdwt *
*===========================================================================*/
static int do_rdwt(int flag_rw)
{
size_t size, size_ret;
u64_t pos;
int r;
pos = make64(m_in.POSITION, m_in.HIGHPOS);
size = m_in.COUNT;
if (rem64u(pos, SECTOR_SIZE) != 0 || size % SECTOR_SIZE != 0) {
printf("Filter: unaligned request from caller!\n");
return EINVAL;
}
buffer = flt_malloc(size, buf_array, BUF_SIZE);
if(flag_rw == FLT_WRITE)
carry(size, flag_rw);
reset_kills();
for (;;) {
size_ret = size;
r = transfer(pos, buffer, &size_ret, flag_rw);
if(r != RET_REDO)
break;
#if DEBUG
printf("Filter: transfer yielded RET_REDO, checking drivers\n");
#endif
if((r = check_driver(DRIVER_MAIN)) != OK) break;
if((r = check_driver(DRIVER_BACKUP)) != OK) break;
}
if(r == OK && flag_rw == FLT_READ)
carry(size_ret, flag_rw);
flt_free(buffer, size, buf_array);
return r != OK ? r : size_ret;
}
/*===========================================================================*
* do_vrdwt *
*===========================================================================*/
static int do_vrdwt(int flag_rw)
{
size_t size, size_ret, bytes;
int grants;
int r, i;
u64_t pos;
iovec_t iov_proc[NR_IOREQS];
/* Extract informations. */
grants = m_in.COUNT;
if((r = sys_safecopyfrom(who_e, grant_id, 0, (vir_bytes) iov_proc,
grants * sizeof(iovec_t), D)) != OK) {
panic("copying in grant vector failed: %d", r);
}
pos = make64(m_in.POSITION, m_in.HIGHPOS);
for(size = 0, i = 0; i < grants; i++)
size += iov_proc[i].iov_size;
if (rem64u(pos, SECTOR_SIZE) != 0 || size % SECTOR_SIZE != 0) {
printf("Filter: unaligned request from caller!\n");
return EINVAL;
}
buffer = flt_malloc(size, buf_array, BUF_SIZE);
if(flag_rw == FLT_WRITE)
vcarry(grants, iov_proc, flag_rw, size);
reset_kills();
for (;;) {
size_ret = size;
r = transfer(pos, buffer, &size_ret, flag_rw);
if(r != RET_REDO)
break;
#if DEBUG
printf("Filter: transfer yielded RET_REDO, checking drivers\n");
#endif
if((r = check_driver(DRIVER_MAIN)) != OK) break;
if((r = check_driver(DRIVER_BACKUP)) != OK) break;
}
if(r != OK) {
flt_free(buffer, size, buf_array);
return r;
}
if(flag_rw == FLT_READ)
vcarry(grants, iov_proc, flag_rw, size_ret);
/* Set the result-iovec. */
for(i = 0; i < grants && size_ret > 0; i++) {
bytes = MIN(size_ret, iov_proc[i].iov_size);
iov_proc[i].iov_size -= bytes;
size_ret -= bytes;
}
/* Copy the caller's grant-table back. */
if((r = sys_safecopyto(who_e, grant_id, 0, (vir_bytes) iov_proc,
grants * sizeof(iovec_t), D)) != OK) {
panic("copying out grant vector failed: %d", r);
}
flt_free(buffer, size, buf_array);
return OK;
}
/*===========================================================================*
* do_ioctl *
*===========================================================================*/
static int do_ioctl(message *m)
{
struct partition sizepart;
switch(m->REQUEST) {
case DIOCSETP:
case DIOCTIMEOUT:
case DIOCOPENCT:
/* These do not make sense for us. */
return EINVAL;
case DIOCGETP:
memset(&sizepart, 0, sizeof(sizepart));
/* The presented disk size is the raw partition size,
* corrected for space needed for checksums.
*/
sizepart.size = convert(get_raw_size());
if(sys_safecopyto(proc_e, (vir_bytes) grant_id, 0,
(vir_bytes) &sizepart,
sizeof(struct partition), D) != OK) {
printf("Filter: DIOCGETP safecopyto failed\n");
return EIO;
}
break;
default:
printf("Filter: unknown ioctl request: %d!\n", m->REQUEST);
return EINVAL;
}
return OK;
}
/*===========================================================================*
* parse_arguments *
*===========================================================================*/
static int parse_arguments(int argc, char *argv[])
{
if(argc != 2)
return EINVAL;
optset_parse(optset_table, argv[1]);
if (MAIN_LABEL[0] == 0 || MAIN_MINOR < 0 || MAIN_MINOR > 255)
return EINVAL;
if (USE_MIRROR && (BACKUP_LABEL[0] == 0 ||
BACKUP_MINOR < 0 || BACKUP_MINOR > 255))
return EINVAL;
/* Checksumming implies a checksum layout. */
if (USE_CHECKSUM)
USE_SUM_LAYOUT = 1;
/* Determine the checksum size for the chosen checksum type. */
switch (SUM_TYPE) {
case ST_NIL:
SUM_SIZE = 4; /* for the sector number */
break;
case ST_XOR:
SUM_SIZE = 16; /* compatibility */
break;
case ST_CRC:
SUM_SIZE = 4;
break;
case ST_MD5:
SUM_SIZE = 16;
break;
default:
return EINVAL;
}
if (NR_SUM_SEC <= 0 || SUM_SIZE * NR_SUM_SEC > SECTOR_SIZE)
return EINVAL;
#if DEBUG
printf("Filter starting. Configuration:\n");
printf(" USE_CHECKSUM : %3s ", USE_CHECKSUM ? "yes" : "no");
printf(" USE_MIRROR : %3s\n", USE_MIRROR ? "yes" : "no");
if (USE_CHECKSUM) {
printf(" BAD_SUM_ERROR : %3s ",
BAD_SUM_ERROR ? "yes" : "no");
printf(" NR_SUM_SEC : %3d\n", NR_SUM_SEC);
printf(" SUM_TYPE : ");
switch (SUM_TYPE) {
case ST_NIL: printf("nil"); break;
case ST_XOR: printf("xor"); break;
case ST_CRC: printf("crc"); break;
case ST_MD5: printf("md5"); break;
}
printf(" SUM_SIZE : %3d\n", SUM_SIZE);
}
else printf(" USE_SUM_LAYOUT : %3s\n", USE_SUM_LAYOUT ? "yes" : "no");
printf(" N : %3dx M : %3dx T : %3ds\n",
NR_RETRIES, NR_RESTARTS, DRIVER_TIMEOUT);
printf(" MAIN_LABEL / MAIN_MINOR : %19s / %d\n",
MAIN_LABEL, MAIN_MINOR);
if (USE_MIRROR) {
printf(" BACKUP_LABEL / BACKUP_MINOR : %15s / %d\n",
BACKUP_LABEL, BACKUP_MINOR);
}
#endif
/* Convert timeout seconds to ticks. */
DRIVER_TIMEOUT *= sys_hz();
return OK;
}
/*===========================================================================*
* main *
*===========================================================================*/
int main(int argc, char *argv[])
{
message m_out;
int r;
/* SEF local startup. */
env_setargs(argc, argv);
sef_local_startup();
for (;;) {
/* Wait for request. */
if(sef_receive(ANY, &m_in) != OK) {
panic("sef_receive failed");
}
#if DEBUG2
printf("Filter: got request %d from %d\n",
m_in.m_type, m_in.m_source);
#endif
who_e = m_in.m_source;
proc_e = m_in.IO_ENDPT;
grant_id = (cp_grant_id_t) m_in.IO_GRANT;
/* Forword the request message to the drivers. */
switch(m_in.m_type) {
case DEV_OPEN: /* open/close is a noop for filter. */
case DEV_CLOSE: r = OK; break;
case DEV_READ_S: r = do_rdwt(FLT_READ); break;
case DEV_WRITE_S: r = do_rdwt(FLT_WRITE); break;
case DEV_GATHER_S: r = do_vrdwt(FLT_READ); break;
case DEV_SCATTER_S: r = do_vrdwt(FLT_WRITE); break;
case DEV_IOCTL_S: r = do_ioctl(&m_in); break;
default:
printf("Filter: ignoring unknown request %d from %d\n",
m_in.m_type, m_in.m_source);
continue;
}
#if DEBUG2
printf("Filter: replying with code %d\n", r);
#endif
/* Send back reply message. */
m_out.m_type = TASK_REPLY;
m_out.REP_ENDPT = proc_e;
m_out.REP_STATUS = r;
send(who_e, &m_out);
}
return 0;
}
/*===========================================================================*
* sef_local_startup *
*===========================================================================*/
PRIVATE void sef_local_startup(void)
{
/* Register init callbacks. */
sef_setcb_init_fresh(sef_cb_init_fresh);
sef_setcb_init_restart(sef_cb_init_fresh);
/* No live update support for now. */
/* Register signal callbacks. */
sef_setcb_signal_handler(sef_cb_signal_handler);
/* Let SEF perform startup. */
sef_startup();
}
/*===========================================================================*
* sef_cb_init_fresh *
*===========================================================================*/
PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *info)
{
/* Initialize the filter driver. */
int r;
r = parse_arguments(env_argc, env_argv);
if(r != OK) {
printf("Filter: wrong argument!\n");
return 1;
}
if ((buf_array = flt_malloc(BUF_SIZE, NULL, 0)) == NULL)
panic("no memory available");
sum_init();
driver_init();
return(OK);
}
/*===========================================================================*
* sef_cb_signal_handler *
*===========================================================================*/
PRIVATE void sef_cb_signal_handler(int signo)
{
/* Only check for termination signal, ignore anything else. */
if (signo != SIGTERM) return;
/* If so, shut down this driver. */
#if DEBUG
printf("Filter: shutdown...\n");
#endif
driver_shutdown();
exit(0);
}