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minix/servers/rs/main.c
Thomas Veerman 0bd011affd PM: extend srv_fork to set a specific UID 
Currently, all servers and drivers run as root as they are forks of
RS. srv_fork now tells PM with which credentials to run the resulting
fork. Subsequently, PM lets VFS now as well.

This patch also fixes the following bugs:
 - RS doesn't initialize the setugid variable during exec, causing the
   servers and drivers to run setuid rendering the srv_fork extension
   useless.
 - PM erroneously tells VFS to run processes setuid. This doesn't
   actually lead to setuid processes as VFS sets {r,e}uid and {r,e}gid
   properly before checking PM's approval.
2012-01-30 15:16:19 +00:00

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/* Reincarnation Server. This servers starts new system services and detects
* they are exiting. In case of errors, system services can be restarted.
* The RS server periodically checks the status of all registered services
* services to see whether they are still alive. The system services are
* expected to periodically send a heartbeat message.
*
* Changes:
* Nov 22, 2009: rewrite of boot process (Cristiano Giuffrida)
* Jul 22, 2005: Created (Jorrit N. Herder)
*/
#include "inc.h"
#include <fcntl.h>
#include <a.out.h>
#include <minix/crtso.h>
#include "kernel/const.h"
#include "kernel/type.h"
#include "kernel/proc.h"
/* Declare some local functions. */
FORWARD _PROTOTYPE(void boot_image_info_lookup, ( endpoint_t endpoint,
struct boot_image *image,
struct boot_image **ip, struct boot_image_priv **pp,
struct boot_image_sys **sp, struct boot_image_dev **dp) );
FORWARD _PROTOTYPE(void catch_boot_init_ready, (endpoint_t endpoint) );
FORWARD _PROTOTYPE(void get_work, (message *m_ptr, int *status_ptr) );
/* Flag set when memory unmapping can be done. */
EXTERN int unmap_ok;
/* 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) );
FORWARD _PROTOTYPE( int sef_cb_signal_manager, (endpoint_t target, int signo) );
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC int main(void)
{
/* This is the main routine of this service. The main loop consists of
* three major activities: getting new work, processing the work, and
* sending the reply. The loop never terminates, unless a panic occurs.
*/
message m; /* request message */
int ipc_status; /* status code */
int call_nr, who_e,who_p; /* call number and caller */
int result; /* result to return */
int s;
/* SEF local startup. */
sef_local_startup();
if (OK != (s=sys_getmachine(&machine)))
panic("couldn't get machine info: %d", s);
/* Main loop - get work and do it, forever. */
while (TRUE) {
/* Wait for request message. */
get_work(&m, &ipc_status);
who_e = m.m_source;
if(rs_isokendpt(who_e, &who_p) != OK) {
panic("message from bogus source: %d", who_e);
}
call_nr = m.m_type;
/* Now determine what to do. Four types of requests are expected:
* - Heartbeat messages (notifications from registered system services)
* - System notifications (synchronous alarm)
* - User requests (control messages to manage system services)
* - Ready messages (reply messages from registered services)
*/
/* Notification messages are control messages and do not need a reply.
* These include heartbeat messages and system notifications.
*/
if (is_ipc_notify(ipc_status)) {
switch (who_p) {
case CLOCK:
do_period(&m); /* check services status */
continue;
default: /* heartbeat notification */
if (rproc_ptr[who_p] != NULL) { /* mark heartbeat time */
rproc_ptr[who_p]->r_alive_tm = m.NOTIFY_TIMESTAMP;
} else {
printf("RS: warning: got unexpected notify message from %d\n",
m.m_source);
}
}
}
/* If we get this far, this is a normal request.
* Handle the request and send a reply to the caller.
*/
else {
if (call_nr != COMMON_GETSYSINFO &&
(call_nr < RS_RQ_BASE || call_nr >= RS_RQ_BASE+0x100))
{
/* Ignore invalid requests. Do not try to reply. */
printf("RS: warning: got invalid request %d from endpoint %d\n",
call_nr, m.m_source);
continue;
}
/* Handler functions are responsible for permission checking. */
switch(call_nr) {
/* User requests. */
case RS_UP: result = do_up(&m); break;
case RS_DOWN: result = do_down(&m); break;
case RS_REFRESH: result = do_refresh(&m); break;
case RS_RESTART: result = do_restart(&m); break;
case RS_SHUTDOWN: result = do_shutdown(&m); break;
case RS_UPDATE: result = do_update(&m); break;
case RS_CLONE: result = do_clone(&m); break;
case RS_EDIT: result = do_edit(&m); break;
case COMMON_GETSYSINFO:
result = do_getsysinfo(&m); break;
case RS_LOOKUP: result = do_lookup(&m); break;
/* Ready messages. */
case RS_INIT: result = do_init_ready(&m); break;
case RS_LU_PREPARE: result = do_upd_ready(&m); break;
default:
printf("RS: warning: got unexpected request %d from %d\n",
m.m_type, m.m_source);
result = EINVAL;
}
/* Finally send reply message, unless disabled. */
if (result != EDONTREPLY) {
m.m_type = result;
reply(who_e, NULL, &m);
}
}
}
}
/*===========================================================================*
* sef_local_startup *
*===========================================================================*/
PRIVATE void sef_local_startup()
{
/* Register init callbacks. */
sef_setcb_init_response(do_init_ready);
sef_setcb_init_fresh(sef_cb_init_fresh);
sef_setcb_init_restart(sef_cb_init_fail);
/* Register live update callbacks. */
sef_setcb_lu_response(do_upd_ready);
/* Register signal callbacks. */
sef_setcb_signal_handler(sef_cb_signal_handler);
sef_setcb_signal_manager(sef_cb_signal_manager);
/* Let SEF perform startup. */
sef_startup();
}
/*===========================================================================*
* sef_cb_init_fresh *
*===========================================================================*/
PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
{
/* Initialize the reincarnation server. */
struct boot_image *ip;
int s,i;
int nr_image_srvs, nr_image_priv_srvs, nr_uncaught_init_srvs;
struct rproc *rp;
struct rprocpub *rpub;
struct boot_image image[NR_BOOT_PROCS];
struct boot_image_priv *boot_image_priv;
struct boot_image_sys *boot_image_sys;
struct boot_image_dev *boot_image_dev;
int ipc_to;
int *calls;
int all_c[] = { ALL_C, NULL_C };
int no_c[] = { NULL_C };
/* See if we run in verbose mode. */
env_parse("rs_verbose", "d", 0, &rs_verbose, 0, 1);
if ((s = sys_getinfo(GET_HZ, &system_hz, sizeof(system_hz), 0, 0)) != OK)
panic("Cannot get system timer frequency\n");
/* Initialize the global init descriptor. */
rinit.rproctab_gid = cpf_grant_direct(ANY, (vir_bytes) rprocpub,
sizeof(rprocpub), CPF_READ);
if(!GRANT_VALID(rinit.rproctab_gid)) {
panic("unable to create rprocpub table grant: %d", rinit.rproctab_gid);
}
/* Initialize some global variables. */
rupdate.flags = 0;
shutting_down = FALSE;
/* Get a copy of the boot image table. */
if ((s = sys_getimage(image)) != OK) {
panic("unable to get copy of boot image table: %d", s);
}
/* Determine the number of system services in the boot image table. */
nr_image_srvs = 0;
for(i=0;i<NR_BOOT_PROCS;i++) {
ip = &image[i];
/* System services only. */
if(iskerneln(_ENDPOINT_P(ip->endpoint))) {
continue;
}
nr_image_srvs++;
}
/* Determine the number of entries in the boot image priv table and make sure
* it matches the number of system services in the boot image table.
*/
nr_image_priv_srvs = 0;
for (i=0; boot_image_priv_table[i].endpoint != NULL_BOOT_NR; i++) {
boot_image_priv = &boot_image_priv_table[i];
/* System services only. */
if(iskerneln(_ENDPOINT_P(boot_image_priv->endpoint))) {
continue;
}
nr_image_priv_srvs++;
}
if(nr_image_srvs != nr_image_priv_srvs) {
panic("boot image table and boot image priv table mismatch");
}
/* Reset the system process table. */
for (rp=BEG_RPROC_ADDR; rp<END_RPROC_ADDR; rp++) {
rp->r_flags = 0;
rp->r_pub = &rprocpub[rp - rproc];
rp->r_pub->in_use = FALSE;
}
/* Initialize the system process table in 4 steps, each of them following
* the appearance of system services in the boot image priv table.
* - Step 1: set priviliges, sys properties, and dev properties (if any)
* for every system service.
*/
for (i=0; boot_image_priv_table[i].endpoint != NULL_BOOT_NR; i++) {
boot_image_priv = &boot_image_priv_table[i];
/* System services only. */
if(iskerneln(_ENDPOINT_P(boot_image_priv->endpoint))) {
continue;
}
/* Lookup the corresponding entries in other tables. */
boot_image_info_lookup(boot_image_priv->endpoint, image,
&ip, NULL, &boot_image_sys, &boot_image_dev);
rp = &rproc[boot_image_priv - boot_image_priv_table];
rpub = rp->r_pub;
/*
* Set privileges.
*/
/* Get label. */
strcpy(rpub->label, boot_image_priv->label);
/* Force a static priv id for system services in the boot image. */
rp->r_priv.s_id = static_priv_id(
_ENDPOINT_P(boot_image_priv->endpoint));
/* Initialize privilege bitmaps and signal manager. */
rp->r_priv.s_flags = boot_image_priv->flags; /* priv flags */
rp->r_priv.s_trap_mask= SRV_OR_USR(rp, SRV_T, USR_T); /* traps */
ipc_to = SRV_OR_USR(rp, SRV_M, USR_M); /* targets */
fill_send_mask(&rp->r_priv.s_ipc_to, ipc_to == ALL_M);
rp->r_priv.s_sig_mgr= SRV_OR_USR(rp, SRV_SM, USR_SM); /* sig mgr */
rp->r_priv.s_bak_sig_mgr = NONE; /* backup sig mgr */
/* Initialize kernel call mask bitmap. */
calls = SRV_OR_USR(rp, SRV_KC, USR_KC) == ALL_C ? all_c : no_c;
fill_call_mask(calls, NR_SYS_CALLS,
rp->r_priv.s_k_call_mask, KERNEL_CALL, TRUE);
/* Set the privilege structure. */
if(boot_image_priv->endpoint != RS_PROC_NR) {
if ((s = sys_privctl(ip->endpoint, SYS_PRIV_SET_SYS, &(rp->r_priv)))
!= OK) {
panic("unable to set privilege structure: %d", s);
}
}
/* Synch the privilege structure with the kernel. */
if ((s = sys_getpriv(&(rp->r_priv), ip->endpoint)) != OK) {
panic("unable to synch privilege structure: %d", s);
}
/*
* Set sys properties.
*/
rpub->sys_flags = boot_image_sys->flags; /* sys flags */
/*
* Set dev properties.
*/
rpub->dev_flags = boot_image_dev->flags; /* device flags */
rpub->dev_nr = boot_image_dev->dev_nr; /* major device number */
rpub->dev_style = boot_image_dev->dev_style; /* device style */
rpub->dev_style2 = boot_image_dev->dev_style2; /* device style 2 */
/* Get process name. */
strcpy(rpub->proc_name, ip->proc_name);
/* Build command settings. */
rp->r_cmd[0]= '\0';
rp->r_script[0]= '\0';
build_cmd_dep(rp);
/* Initialize vm call mask bitmap. */
calls = SRV_OR_USR(rp, SRV_VC, USR_VC) == ALL_C ? all_c : no_c;
fill_call_mask(calls, NR_VM_CALLS, rpub->vm_call_mask, VM_RQ_BASE, TRUE);
/* Scheduling parameters. */
rp->r_scheduler = SRV_OR_USR(rp, SRV_SCH, USR_SCH);
rp->r_priority = SRV_OR_USR(rp, SRV_Q, USR_Q);
rp->r_quantum = SRV_OR_USR(rp, SRV_QT, USR_QT);
/* Get some settings from the boot image table. */
rpub->endpoint = ip->endpoint;
/* Set some defaults. */
rp->r_old_rp = NULL; /* no old version yet */
rp->r_new_rp = NULL; /* no new version yet */
rp->r_prev_rp = NULL; /* no prev replica yet */
rp->r_next_rp = NULL; /* no next replica yet */
rp->r_uid = 0; /* root */
rp->r_check_tm = 0; /* not checked yet */
getuptime(&rp->r_alive_tm); /* currently alive */
rp->r_stop_tm = 0; /* not exiting yet */
rp->r_restarts = 0; /* no restarts so far */
rp->r_period = 0; /* no period yet */
rp->r_exec = NULL; /* no in-memory copy yet */
rp->r_exec_len = 0;
/* Mark as in use and active. */
rp->r_flags = RS_IN_USE | RS_ACTIVE;
rproc_ptr[_ENDPOINT_P(rpub->endpoint)]= rp;
rpub->in_use = TRUE;
}
/* - Step 2: allow every system service in the boot image to run. */
nr_uncaught_init_srvs = 0;
for (i=0; boot_image_priv_table[i].endpoint != NULL_BOOT_NR; i++) {
boot_image_priv = &boot_image_priv_table[i];
/* System services only. */
if(iskerneln(_ENDPOINT_P(boot_image_priv->endpoint))) {
continue;
}
/* Lookup the corresponding slot in the system process table. */
rp = &rproc[boot_image_priv - boot_image_priv_table];
rpub = rp->r_pub;
/* RS is already running as we speak. */
if(boot_image_priv->endpoint == RS_PROC_NR) {
if ((s = init_service(rp, SEF_INIT_FRESH)) != OK) {
panic("unable to initialize RS: %d", s);
}
continue;
}
/* Allow the service to run. */
if ((s = sched_init_proc(rp)) != OK) {
panic("unable to initialize scheduling: %d", s);
}
if ((s = sys_privctl(rpub->endpoint, SYS_PRIV_ALLOW, NULL)) != OK) {
panic("unable to initialize privileges: %d", s);
}
/* Initialize service. We assume every service will always get
* back to us here at boot time.
*/
if(boot_image_priv->flags & SYS_PROC) {
if ((s = init_service(rp, SEF_INIT_FRESH)) != OK) {
panic("unable to initialize service: %d", s);
}
if(rpub->sys_flags & SF_SYNCH_BOOT) {
/* Catch init ready message now to synchronize. */
catch_boot_init_ready(rpub->endpoint);
}
else {
/* Catch init ready message later. */
nr_uncaught_init_srvs++;
}
}
}
/* - Step 3: let every system service complete initialization by
* catching all the init ready messages left.
*/
while(nr_uncaught_init_srvs) {
catch_boot_init_ready(ANY);
nr_uncaught_init_srvs--;
}
/* - Step 4: all the system services in the boot image are now running.
* Complete the initialization of the system process table in collaboration
* with other system services.
*/
for (i=0; boot_image_priv_table[i].endpoint != NULL_BOOT_NR; i++) {
boot_image_priv = &boot_image_priv_table[i];
/* System services only. */
if(iskerneln(_ENDPOINT_P(boot_image_priv->endpoint))) {
continue;
}
/* Lookup the corresponding slot in the system process table. */
rp = &rproc[boot_image_priv - boot_image_priv_table];
rpub = rp->r_pub;
/* Get pid from PM. */
rp->r_pid = getnpid(rpub->endpoint);
if(rp->r_pid == -1) {
panic("unable to get pid");
}
}
/* Set alarm to periodically check service status. */
if (OK != (s=sys_setalarm(RS_DELTA_T, 0)))
panic("couldn't set alarm: %d", s);
#if USE_LIVEUPDATE
/* Now create a new RS instance with a private page table and let the current
* instance live update into the replica. Clone RS' own slot first.
*/
rp = rproc_ptr[_ENDPOINT_P(RS_PROC_NR)];
if((s = clone_slot(rp, &replica_rp)) != OK) {
panic("unable to clone current RS instance: %d", s);
}
/* Fork a new RS instance with root:operator. */
pid = srv_fork(0, 0);
if(pid == -1) {
panic("unable to fork a new RS instance");
}
replica_pid = pid ? pid : getpid();
replica_endpoint = getnprocnr(replica_pid);
replica_rp->r_pid = replica_pid;
replica_rp->r_pub->endpoint = replica_endpoint;
if(pid == 0) {
/* New RS instance running. */
/* Live update the old instance into the new one. */
s = update_service(&rp, &replica_rp, RS_SWAP);
if(s != OK) {
panic("unable to live update RS: %d", s);
}
cpf_reload();
/* Clean up the old RS instance, the new instance will take over. */
cleanup_service(rp);
/* Map out our own text and data. */
unmap_ok = 1;
#if !defined(__ELF__)
_minix_unmapzero();
#endif
/* Ask VM to pin memory for the new RS instance. */
if((s = vm_memctl(RS_PROC_NR, VM_RS_MEM_PIN)) != OK) {
panic("unable to pin memory for the new RS instance: %d", s);
}
}
else {
/* Old RS instance running. */
/* Set up privileges for the new instance and let it run. */
s = sys_privctl(replica_endpoint, SYS_PRIV_SET_SYS, &(replica_rp->r_priv));
if(s != OK) {
panic("unable to set privileges for the new RS instance: %d", s);
}
if ((s = sched_init_proc(replica_rp)) != OK) {
panic("unable to initialize RS replica scheduling: %d", s);
}
s = sys_privctl(replica_endpoint, SYS_PRIV_YIELD, NULL);
if(s != OK) {
panic("unable to yield control to the new RS instance: %d", s);
}
NOT_REACHABLE;
}
#endif /* USE_LIVEUPDATE */
return(OK);
}
/*===========================================================================*
* sef_cb_signal_handler *
*===========================================================================*/
PRIVATE void sef_cb_signal_handler(int signo)
{
/* Check for known signals, ignore anything else. */
switch(signo) {
case SIGCHLD:
do_sigchld();
break;
case SIGTERM:
do_shutdown(NULL);
break;
}
}
/*===========================================================================*
* sef_cb_signal_manager *
*===========================================================================*/
PRIVATE int sef_cb_signal_manager(endpoint_t target, int signo)
{
/* Process system signal on behalf of the kernel. */
int target_p;
struct rproc *rp;
struct rprocpub *rpub;
message m;
/* Lookup slot. */
if(rs_isokendpt(target, &target_p) != OK || rproc_ptr[target_p] == NULL) {
if(rs_verbose)
printf("RS: ignoring spurious signal %d for process %d\n",
signo, target);
return OK; /* clear the signal */
}
rp = rproc_ptr[target_p];
rpub = rp->r_pub;
/* Don't bother if a termination signal has already been processed. */
if((rp->r_flags & RS_TERMINATED) && !(rp->r_flags & RS_EXITING)) {
return EDEADEPT; /* process is gone */
}
/* Ignore external signals for inactive service instances. */
if( !(rp->r_flags & RS_ACTIVE) && !(rp->r_flags & RS_EXITING)) {
if(rs_verbose)
printf("RS: ignoring signal %d for inactive %s\n",
signo, srv_to_string(rp));
return OK; /* clear the signal */
}
if(rs_verbose)
printf("RS: %s got %s signal %d\n", srv_to_string(rp),
SIGS_IS_TERMINATION(signo) ? "termination" : "non-termination",signo);
/* Print stacktrace if necessary. */
if(SIGS_IS_STACKTRACE(signo)) {
sys_sysctl_stacktrace(target);
}
/* In case of termination signal handle the event. */
if(SIGS_IS_TERMINATION(signo)) {
rp->r_flags |= RS_TERMINATED;
terminate_service(rp);
return EDEADEPT; /* process is now gone */
}
/* Translate every non-termination signal into a message. */
m.m_type = SIGS_SIGNAL_RECEIVED;
m.SIGS_SIG_NUM = signo;
asynsend3(rpub->endpoint, &m, AMF_NOREPLY);
return OK; /* signal has been delivered */
}
/*===========================================================================*
* boot_image_info_lookup *
*===========================================================================*/
PRIVATE void boot_image_info_lookup(endpoint, image, ip, pp, sp, dp)
endpoint_t endpoint;
struct boot_image *image;
struct boot_image **ip;
struct boot_image_priv **pp;
struct boot_image_sys **sp;
struct boot_image_dev **dp;
{
/* Lookup entries in boot image tables. */
int i;
/* When requested, locate the corresponding entry in the boot image table
* or panic if not found.
*/
if(ip) {
for (i=0; i < NR_BOOT_PROCS; i++) {
if(image[i].endpoint == endpoint) {
*ip = &image[i];
break;
}
}
if(i == NR_BOOT_PROCS) {
panic("boot image table lookup failed");
}
}
/* When requested, locate the corresponding entry in the boot image priv table
* or panic if not found.
*/
if(pp) {
for (i=0; boot_image_priv_table[i].endpoint != NULL_BOOT_NR; i++) {
if(boot_image_priv_table[i].endpoint == endpoint) {
*pp = &boot_image_priv_table[i];
break;
}
}
if(i == NULL_BOOT_NR) {
panic("boot image priv table lookup failed");
}
}
/* When requested, locate the corresponding entry in the boot image sys table
* or resort to the default entry if not found.
*/
if(sp) {
for (i=0; boot_image_sys_table[i].endpoint != DEFAULT_BOOT_NR; i++) {
if(boot_image_sys_table[i].endpoint == endpoint) {
*sp = &boot_image_sys_table[i];
break;
}
}
if(boot_image_sys_table[i].endpoint == DEFAULT_BOOT_NR) {
*sp = &boot_image_sys_table[i]; /* accept the default entry */
}
}
/* When requested, locate the corresponding entry in the boot image dev table
* or resort to the default entry if not found.
*/
if(dp) {
for (i=0; boot_image_dev_table[i].endpoint != DEFAULT_BOOT_NR; i++) {
if(boot_image_dev_table[i].endpoint == endpoint) {
*dp = &boot_image_dev_table[i];
break;
}
}
if(boot_image_dev_table[i].endpoint == DEFAULT_BOOT_NR) {
*dp = &boot_image_dev_table[i]; /* accept the default entry */
}
}
}
/*===========================================================================*
* catch_boot_init_ready *
*===========================================================================*/
PRIVATE void catch_boot_init_ready(endpoint)
endpoint_t endpoint;
{
/* Block and catch an init ready message from the given source. */
int r;
int ipc_status;
message m;
struct rproc *rp;
int result;
/* Receive init ready message. */
if ((r = sef_receive_status(endpoint, &m, &ipc_status)) != OK) {
panic("unable to receive init reply: %d", r);
}
if(m.m_type != RS_INIT) {
panic("unexpected reply from service: %d", m.m_source);
}
result = m.RS_INIT_RESULT;
rp = rproc_ptr[_ENDPOINT_P(m.m_source)];
/* Check result. */
if(result != OK) {
panic("unable to complete init for service: %d", m.m_source);
}
/* Send a reply to unblock the service. */
m.m_type = OK;
reply(m.m_source, rp, &m);
/* Mark the slot as no longer initializing. */
rp->r_flags &= ~RS_INITIALIZING;
rp->r_check_tm = 0;
getuptime(&rp->r_alive_tm);
}
/*===========================================================================*
* get_work *
*===========================================================================*/
PRIVATE void get_work(m_ptr, status_ptr)
message *m_ptr; /* pointer to message */
int *status_ptr; /* pointer to status */
{
int r;
if (OK != (r=sef_receive_status(ANY, m_ptr, status_ptr)))
panic("sef_receive_status failed: %d", r);
}
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