minix/lib/libsys/ds.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

269 lines
5.5 KiB
C

#include <minix/ds.h>
#include <string.h>
#include "syslib.h"
static message m;
PRIVATE int do_invoke_ds(int type, const char *ds_name)
{
cp_grant_id_t g_key;
size_t len_key;
int access, r;
if(type == DS_CHECK || type == DS_RETRIEVE_LABEL) {
len_key = DS_MAX_KEYLEN;
access = CPF_WRITE;
} else {
len_key = strlen(ds_name)+1;
access = CPF_READ;
}
/* Grant for key. */
g_key = cpf_grant_direct(DS_PROC_NR, (vir_bytes) ds_name,
len_key, access);
if(!GRANT_VALID(g_key))
return errno;
m.DS_KEY_GRANT = g_key;
m.DS_KEY_LEN = len_key;
r = _taskcall(DS_PROC_NR, type, &m);
cpf_revoke(g_key);
return r;
}
int ds_publish_label(const char *ds_name, u32_t value, int flags)
{
m.DS_VAL = value;
m.DS_FLAGS = DSF_TYPE_LABEL | flags;
return do_invoke_ds(DS_PUBLISH, ds_name);
}
int ds_publish_u32(const char *ds_name, u32_t value, int flags)
{
m.DS_VAL = value;
m.DS_FLAGS = DSF_TYPE_U32 | flags;
return do_invoke_ds(DS_PUBLISH, ds_name);
}
static int ds_publish_raw(const char *ds_name, void *vaddr, size_t length,
int flags)
{
cp_grant_id_t gid;
int r;
/* Grant for memory range. */
gid = cpf_grant_direct(DS_PROC_NR, (vir_bytes)vaddr, length, CPF_READ);
if(!GRANT_VALID(gid))
return errno;
m.DS_VAL = gid;
m.DS_VAL_LEN = length;
m.DS_FLAGS = flags;
r = do_invoke_ds(DS_PUBLISH, ds_name);
cpf_revoke(gid);
return r;
}
int ds_publish_str(const char *ds_name, char *value, int flags)
{
size_t length;
length = strlen(value) + 1;
value[length - 1] = '\0';
return ds_publish_raw(ds_name, value, length, flags | DSF_TYPE_STR);
}
int ds_publish_mem(const char *ds_name, void *vaddr, size_t length, int flags)
{
return ds_publish_raw(ds_name, vaddr, length, flags | DSF_TYPE_MEM);
}
int ds_publish_map(const char *ds_name, void *vaddr, size_t length, int flags)
{
cp_grant_id_t gid;
int r;
if(((vir_bytes)vaddr % CLICK_SIZE != 0) || (length % CLICK_SIZE != 0))
return EINVAL;
/* Grant for mapped memory range. */
gid = cpf_grant_direct(DS_PROC_NR, (vir_bytes)vaddr, length,
CPF_READ | CPF_MAP);
if(!GRANT_VALID(gid))
return errno;
m.DS_VAL = gid;
m.DS_VAL_LEN = length;
m.DS_FLAGS = DSF_TYPE_MAP | flags;
r = do_invoke_ds(DS_PUBLISH, ds_name);
return r;
}
int ds_snapshot_map(const char *ds_name, int *nr_snapshot)
{
int r;
r = do_invoke_ds(DS_SNAPSHOT, ds_name);
*nr_snapshot = m.DS_NR_SNAPSHOT;
return r;
}
int ds_retrieve_label_name(char *ds_name, u32_t num)
{
int r;
m.DS_VAL = num;
r = do_invoke_ds(DS_RETRIEVE_LABEL, ds_name);
return r;
}
int ds_retrieve_label_num(const char *ds_name, u32_t *value)
{
int r;
m.DS_FLAGS = DSF_TYPE_LABEL;
r = do_invoke_ds(DS_RETRIEVE, ds_name);
*value = m.DS_VAL;
return r;
}
int ds_retrieve_u32(const char *ds_name, u32_t *value)
{
int r;
m.DS_FLAGS = DSF_TYPE_U32;
r = do_invoke_ds(DS_RETRIEVE, ds_name);
*value = m.DS_VAL;
return r;
}
static int ds_retrieve_raw(const char *ds_name, char *vaddr, size_t *length,
int flags)
{
cp_grant_id_t gid;
int r;
/* Grant for memory range. */
gid = cpf_grant_direct(DS_PROC_NR, (vir_bytes)vaddr, *length, CPF_WRITE);
if(!GRANT_VALID(gid))
return errno;
m.DS_VAL = gid;
m.DS_VAL_LEN = *length;
m.DS_FLAGS = flags;
r = do_invoke_ds(DS_RETRIEVE, ds_name);
*length = m.DS_VAL_LEN;
cpf_revoke(gid);
return r;
}
int ds_retrieve_str(const char *ds_name, char *value, size_t len_str)
{
int r;
size_t length = len_str + 1;
r = ds_retrieve_raw(ds_name, value, &length, DSF_TYPE_STR);
value[length - 1] = '\0';
return r;
}
int ds_retrieve_mem(const char *ds_name, char *vaddr, size_t *length)
{
return ds_retrieve_raw(ds_name, vaddr, length, DSF_TYPE_MEM);
}
int ds_retrieve_map(const char *ds_name, char *vaddr, size_t *length,
int nr_snapshot, int flags)
{
cp_grant_id_t gid;
int r;
/* Map a mapped memory range. */
if(flags & DSMF_MAP_MAPPED) {
/* Request DS to grant. */
m.DS_FLAGS = DSF_TYPE_MAP | DSMF_MAP_MAPPED;
r = do_invoke_ds(DS_RETRIEVE, ds_name);
if(r != OK)
return r;
/* Do the safemap. */
if(*length > (size_t) m.DS_VAL_LEN)
*length = (size_t) m.DS_VAL_LEN;
*length = (size_t) CLICK_FLOOR(*length);
r = sys_safemap(DS_PROC_NR, m.DS_VAL, 0,
(vir_bytes)vaddr, *length, D, 0);
/* Copy mapped memory range or a snapshot. */
} else if(flags & (DSMF_COPY_MAPPED|DSMF_COPY_SNAPSHOT)) {
/* Grant for memory range first. */
gid = cpf_grant_direct(DS_PROC_NR, (vir_bytes)vaddr,
*length, CPF_WRITE);
if(!GRANT_VALID(gid))
return errno;
m.DS_VAL = gid;
m.DS_VAL_LEN = *length;
if(flags & DSMF_COPY_MAPPED) {
m.DS_FLAGS = DSF_TYPE_MAP | DSMF_COPY_MAPPED;
}
else {
m.DS_NR_SNAPSHOT = nr_snapshot;
m.DS_FLAGS = DSF_TYPE_MAP | DSMF_COPY_SNAPSHOT;
}
r = do_invoke_ds(DS_RETRIEVE, ds_name);
*length = m.DS_VAL_LEN;
cpf_revoke(gid);
}
else {
return EINVAL;
}
return r;
}
int ds_delete_u32(const char *ds_name)
{
m.DS_FLAGS = DSF_TYPE_U32;
return do_invoke_ds(DS_DELETE, ds_name);
}
int ds_delete_str(const char *ds_name)
{
m.DS_FLAGS = DSF_TYPE_STR;
return do_invoke_ds(DS_DELETE, ds_name);
}
int ds_delete_mem(const char *ds_name)
{
m.DS_FLAGS = DSF_TYPE_MEM;
return do_invoke_ds(DS_DELETE, ds_name);
}
int ds_delete_map(const char *ds_name)
{
m.DS_FLAGS = DSF_TYPE_MAP;
return do_invoke_ds(DS_DELETE, ds_name);
}
int ds_delete_label(const char *ds_name)
{
m.DS_FLAGS = DSF_TYPE_LABEL;
return do_invoke_ds(DS_DELETE, ds_name);
}
int ds_subscribe(const char *regexp, int flags)
{
m.DS_FLAGS = flags;
return do_invoke_ds(DS_SUBSCRIBE, regexp);
}
int ds_check(char *ds_key, int *type)
{
int r;
r = do_invoke_ds(DS_CHECK, ds_key);
*type = m.DS_FLAGS;
return r;
}