minix/servers/rs/utility.c

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Rewrite of boot process KERNEL CHANGES: - The kernel only knows about privileges of kernel tasks and the root system process (now RS). - Kernel tasks and the root system process are the only processes that are made schedulable by the kernel at startup. All the other processes in the boot image don't get their privileges set at startup and are inhibited from running by the RTS_NO_PRIV flag. - Removed the assumption on the ordering of processes in the boot image table. System processes can now appear in any order in the boot image table. - Privilege ids can now be assigned both statically or dynamically. The kernel assigns static privilege ids to kernel tasks and the root system process. Each id is directly derived from the process number. - User processes now all share the static privilege id of the root user process (now INIT). - sys_privctl split: we have more calls now to let RS set privileges for system processes. SYS_PRIV_ALLOW / SYS_PRIV_DISALLOW are only used to flip the RTS_NO_PRIV flag and allow / disallow a process from running. SYS_PRIV_SET_SYS / SYS_PRIV_SET_USER are used to set privileges for a system / user process. - boot image table flags split: PROC_FULLVM is the only flag that has been moved out of the privilege flags and is still maintained in the boot image table. All the other privilege flags are out of the kernel now. RS CHANGES: - RS is the only user-space process who gets to run right after in-kernel startup. - RS uses the boot image table from the kernel and three additional boot image info table (priv table, sys table, dev table) to complete the initialization of the system. - RS checks that the entries in the priv table match the entries in the boot image table to make sure that every process in the boot image gets schedulable. - RS only uses static privilege ids to set privileges for system services in the boot image. - RS includes basic memory management support to allocate the boot image buffer dynamically during initialization. The buffer shall contain the executable image of all the system services we would like to restart after a crash. - First step towards decoupling between resource provisioning and resource requirements in RS: RS must know what resources it needs to restart a process and what resources it has currently available. This is useful to tradeoff reliability and resource consumption. When required resources are missing, the process cannot be restarted. In that case, in the future, a system flag will tell RS what to do. For example, if CORE_PROC is set, RS should trigger a system-wide panic because the system can no longer function correctly without a core system process. PM CHANGES: - The process tree built at initialization time is changed to have INIT as root with pid 0, RS child of INIT and all the system services children of RS. This is required to make RS in control of all the system services. - PM no longer registers labels for system services in the boot image. This is now part of RS's initialization process.
2009-12-11 01:08:19 +01:00
/* This file contains some utility routines for RS.
*
* Changes:
* Nov 22, 2009: Created (Cristiano Giuffrida)
*/
#include "inc.h"
Initialization protocol for system services. SYSLIB CHANGES: - SEF framework now supports a new SEF Init request type from RS. 3 different callbacks are available (init_fresh, init_lu, init_restart) to specify initialization code when a service starts fresh, starts after a live update, or restarts. SYSTEM SERVICE CHANGES: - Initialization code for system services is now enclosed in a callback SEF will automatically call at init time. The return code of the callback will tell RS whether the initialization completed successfully. - Each init callback can access information passed by RS to initialize. As of now, each system service has access to the public entries of RS's system process table to gather all the information required to initialize. This design eliminates many existing or potential races at boot time and provides a uniform initialization interface to system services. The same interface will be reused for the upcoming publish/subscribe model to handle dynamic registration / deregistration of system services. VM CHANGES: - Uniform privilege management for all system services. Every service uses the same call mask format. For boot services, VM copies the call mask from init data. For dynamic services, VM still receives the call mask via rs_set_priv call that will be soon replaced by the upcoming publish/subscribe model. RS CHANGES: - The system process table has been reorganized and split into private entries and public entries. Only the latter ones are exposed to system services. - VM call masks are now entirely configured in rs/table.c - RS has now its own slot in the system process table. Only kernel tasks and user processes not included in the boot image are now left out from the system process table. - RS implements the initialization protocol for system services. - For services in the boot image, RS blocks till initialization is complete and panics when failure is reported back. Services are initialized in their order of appearance in the boot image priv table and RS blocks to implements synchronous initialization for every system service having the flag SF_SYNCH_BOOT set. - For services started dynamically, the initialization protocol is implemented as though it were the first ping for the service. In this case, if the system service fails to report back (or reports failure), RS brings the service down rather than trying to restart it.
2010-01-08 02:20:42 +01:00
/*===========================================================================*
* init_service *
*===========================================================================*/
PUBLIC int init_service(rp, type)
struct rproc *rp; /* pointer to process slot */
int type; /* type of initialization */
{
int r;
message m;
struct rprocpub *rpub;
rpub = rp->r_pub;
rp->r_flags |= RS_INITIALIZING; /* now initializing */
rp->r_check_tm = rp->r_alive_tm + 1; /* expect reply within period */
m.m_type = RS_INIT;
m.RS_INIT_TYPE = type;
m.RS_INIT_RPROCTAB_GID = rinit.rproctab_gid;
r = asynsend(rpub->endpoint, &m);
return r;
}
/*===========================================================================*
* fill_call_mask *
*===========================================================================*/
PUBLIC void fill_call_mask(calls, tot_nr_calls, call_mask, call_base, is_init)
int *calls; /* the unordered set of calls */
int tot_nr_calls; /* the total number of calls */
bitchunk_t *call_mask; /* the call mask to fill in */
int call_base; /* the base offset for the calls */
int is_init; /* set when initializing a call mask */
{
/* Fill a call mask from an unordered set of calls. */
int i;
int call_mask_size, nr_calls;
call_mask_size = BITMAP_CHUNKS(tot_nr_calls);
/* Count the number of calls to fill in. */
nr_calls = 0;
for(i=0; calls[i] != SYS_NULL_C; i++) {
nr_calls++;
}
/* See if all calls are allowed and call mask must be completely filled. */
if(nr_calls == 1 && calls[0] == SYS_ALL_C) {
for(i=0; i < call_mask_size; i++) {
call_mask[i] = (~0);
}
}
else {
/* When initializing, reset the mask first. */
if(is_init) {
for(i=0; i < call_mask_size; i++) {
call_mask[i] = 0;
}
}
/* Enter calls bit by bit. */
for(i=0; i < nr_calls; i++) {
SET_BIT(call_mask, calls[i] - call_base);
}
}
}
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 02:15:29 +01:00
/*===========================================================================*
* srv_to_string *
*===========================================================================*/
PUBLIC char* srv_to_string(rp)
struct rproc *rp; /* pointer to process slot */
{
struct rprocpub *rpub;
int slot_nr;
char *srv_string;
static char srv_string_pool[3][RS_MAX_LABEL_LEN + (DEBUG ? 256 : 64)];
static int srv_string_pool_index = 0;
rpub = rp->r_pub;
slot_nr = rp - rproc;
srv_string = srv_string_pool[srv_string_pool_index];
srv_string_pool_index = (srv_string_pool_index + 1) % 3;
#define srv_str(cmd) ((cmd) == NULL || (cmd)[0] == '\0' ? "_" : (cmd))
#define srv_ep_str(rp) (itoa((rp)->r_pub->endpoint))
#define srv_active_str(rp) ((rp)->r_flags & RS_ACTIVE ? "*" : " ")
#define srv_version_str(rp) ((rp)->r_new_rp || (rp)->r_next_rp ? "-" : \
((rp)->r_old_rp || (rp)->r_prev_rp ? "+" : " "))
#if DEBUG
sprintf(srv_string, "service '%s'%s%s(slot %d, ep %d, pid %d, cmd %s, script %s, proc %s, major %d, style %d, flags 0x%03x, sys_flags 0x%02x)",
rpub->label, srv_active_str(rp), srv_version_str(rp),
slot_nr, rpub->endpoint, rp->r_pid, srv_str(rp->r_cmd),
srv_str(rp->r_script), srv_str(rpub->proc_name), rpub->dev_nr,
rpub->dev_style, rp->r_flags, rpub->sys_flags);
#else
sprintf(srv_string, "service '%s'%s%s(slot %d, ep %d, pid %d)",
rpub->label, srv_active_str(rp), srv_version_str(rp),
slot_nr, rpub->endpoint, rp->r_pid);
#endif
return srv_string;
}
/*===========================================================================*
* reply *
*===========================================================================*/
PUBLIC void reply(who, m_ptr)
endpoint_t who; /* replyee */
message *m_ptr; /* reply message */
{
int r; /* send status */
r = sendnb(who, m_ptr); /* send the message */
if (r != OK)
printf("RS: unable to send reply to %d: %d\n", who, r);
}
/*===========================================================================*
* late_reply *
*===========================================================================*/
PUBLIC void late_reply(rp, code)
struct rproc *rp; /* pointer to process slot */
int code; /* status code */
{
/* If a caller is waiting for a reply, unblock it. */
struct rprocpub *rpub;
rpub = rp->r_pub;
if(rp->r_flags & RS_LATEREPLY) {
message m;
m.m_type = code;
if(rs_verbose)
printf("RS: %s late reply %d to %d for request %d\n",
srv_to_string(rp), code, rp->r_caller, rp->r_caller_request);
reply(rp->r_caller, &m);
rp->r_flags &= ~RS_LATEREPLY;
}
}
/*===========================================================================*
* rs_isokendpt *
*===========================================================================*/
PUBLIC int rs_isokendpt(int endpoint, int *proc)
{
*proc = _ENDPOINT_P(endpoint);
if(*proc < -NR_TASKS || *proc >= NR_PROCS)
return EINVAL;
return OK;
}