SRI-NOSC/ncpd/1main.c
#
/* 1main.c */
#include "param.h" /*so we can use errs in user.h*/
#define NO_U X
#include "user.h" /*to get stnd error names*/
#include "files.h"
#include "globvar.h"
#include "probuf.h"
#include "kread.h"
/* SCCS PROGRAM IDENTIFICATION STRING */
char id_1main[] "~|^`1main.c\tV3.9E1\t09Mar78\n";
/* name:
main
function:
initialization and main loop of ARPANet ncp daemon.
algorithm:
expects daemon communication to be in file descriptor zero
catch quit signals and direct them to emer_dwn
catch interrupt signals and direct them to clean_dwn
catch toggle signals and direct them to toggle_debug
initialize the log via log_init
initializes host status file via hs_init
writes kernel reset(0) which resets kernel for all hosts
via kw_reset.
enters main system loop:
read from kernel.
initialize flags.
decode kernel instruction.
if protocol is to be sent, send it via send_pro.
check for any server files timing out
if we fall out of loop, log error and die
parameters:
none.
returns:
nothing.
globals:
k_file=
kr_bytes=
pro2send=
calls:
kw_reset
kr_dcode
log_bin
log_asc
send_pro
read (sys)
hs_init
log_init
kw_timeo
called by:
started by "smalldaemon" after ncpkernel file has be opened
history:
initial coding 12/09/74 by G. R. Grossman.
modification for new rst initialization 1/17/75 by G. R. Grossman.
initializing host status file added 5/28/75 by G. R. Grossman
modification to expect ncpkernel communication in file descriptor
zero 10/20/75 by S. F. Holmgren
modified to call fi_timeo 6/15/76 by S. F. Holmgren
modified to call kw_timo instead of fi_timeo by greep
modified to send quit signals to emer_dwn and catch interrupts
and send them to clean_dwn 1/28/77 by S. M. Abraham
modified to call log_init 3/2/77, S.M. Abraham
moved rst logic to when IMP interface logic is recieved
8/31/77 by Greg Noel
modified to toggle debugging switches when a signal is recieved
10/5/77 by Greg Noel
cosmetic mods to log messages 01Feb78 J.S.Goldberg
*/
main(argc, argv)
int argc;
char **argv;
{
extern errno; /* interface to system error codes */
/*# define EINTR 4 /* error code for interrupted system call */
/*the line above is made unnecessary by including error names from user.h*/
extern emer_dwn();
extern clean_dwn();
extern toggle_debug();
/* set up to call emer_dwn on quit signals */
signal (1,1);
signal (2,1);
signal (3,1);
signal (10, &emer_dwn ); /* changed from 4 - flt emt */
/* set up to call clean_dwn on interrupt signals */
signal (5, &clean_dwn);
/* set up to call toggle_debug on signal 11 (segmentation err) */
signal (11, &toggle_debug);
/* if debugging requested, turn it on */
if(argc > 1) toggle_debug();
close (2);
dup (1); /*so perror comes out on re-directed output*/
log_init() ; /* init the log */
k_file = 0; /* make sure k_file looks in zero */
hs_init(); /* init host status file */
kw_reset(0); /* reset all hosts in kernel */
init_skts(); /* initialize socket structs */
/* main loop of the ncp daemon */
/* read until eof or error */
for(;;) if( (kr_bytes =read(k_file,&kr_buf,1024)) > 0 )
{
pro2send = 0; /* reset protocol transmission flag */
kr_dcode(); /* go decode and execute
instruction from kernel */
if (pro2send) /* host-host protocol commands
queued up to send? */
send_pro(); /* send them if so */
if( ( stimeo || ftimeo ) && (timeo == 0) )
kw_timo (); /* set timer */
} else /* potential eof or error */
/* exit loop if not interrupted system call -- i.e.,
continue if read was interrupted by an external
kill that elected not to quit */
if(kr_bytes != -1 || errno != EINTR) break;
/* end of main loop */
/* the kernel file has closed unexpectedly, so dump */
die("main: Kernel file closed unexpectedly");
}
/* name:
die
function:
fault termination of the ncp daemon. logs a message and
terminates with a bus error to force dump.
algorithm:
log message via log_asc.
force bus error by storing into location 1.
parameters:
s pointer to ascii string to be logged as cause of
termination.
returns:
never.
globals:
none.
calls:
hs_update
log_asc
called by:
many routines.
history:
initial coding 1/7/75 by G. R. Grossman
*/
die(s)
char *s;
{
register int *odd; /* will contain odd address to force
bus error */
hs_update(0,host_dead) ; /* mark us dead */
log_asc(s); /* log the cause of termination */
odd = 1; /* point at odd address */
*odd = 0; /* force bus error */
}
/* name:
emer_dwn
function:
take the network down in an emergency and produce a core image
algorithm:
call daemon_dwn to to cleanly take down the network,
and call "die" to log the occurence and produce a core dump
parameters:
none
returns:
since it terminates the ncpdaemon, it doesn't return
globals:
none
calls:
daemon_dwn to take the network down
die to log the occurence and produce a core dump
called by:
quit signal sent to the largedaemon
history:
initial coding 1/28/77 by S. M. Abraham
*/
emer_dwn()
{
daemon_dwn(); /* take the network down */
die("emer_dwn: Received a quit signal");
}
/* name:
clean_dwn
function:
cleanly takes down the network upon interception of interrupt signal
algorithm:
take the network down by calling daemon_dwn
log reason why net was taken down
exit (thereby terminating the largedaemon)
parameters:
none
returns:
0 as status to the exit system call
globals:
none
calls:
daemon_dwn to take the network down
log_asc to log reason
exit (sys) to terminate the largedaemon process
called by:
interrupt signal sent to the largedaemon
history:
initial coding 1/28/77 by S. M. Abraham
*/
clean_dwn()
{
daemon_dwn(); /* take down the network */
log_asc("Received an interrupt signal") ; /* log reason */
exit(0); /* terminate the largedaemon */
}
/* name:
daemon_dwn
function:
tell the imp we are going down and sleep for awhile
and
clean up any kernel connections
algorithm:
mark us dead externally (in the host status file)
send a host going down message to the imp and sleep for awhile
send a reset (host=0) to the kernel to clean things up
for all files not in the null state
tell the kernel to inform any waiting users that the file has
been closed, and then tell kernel to release the file
close the kernel file
parameters:
none
returns:
nothing
globals:
k_file
calls:
hs_update
hw_dwn
sleep (sys)
kw_reset
kw_frlse
log_asc
close (sys)
called by:
emer_dwn (quit signal to the largedaemon)
clean_dwn (interrupt signal to the largedaemon)
history:
initial coding 6/23/76 by S. F. Holmgren.
modified by Abraham (JSK) to correct order of release/ready
modified not to log reason for occurence, and to close the
kernel file 1/28/77, S. M. Abraham
modified to call hs_update, 3/1/77, S.M. Abraham
modified to do kw_rdy before kw_frlse, 3/31/77, S.M. Abraham
*/
daemon_dwn()
{
register struct file *f_p;
/* mark us dead in the host_status file */
hs_update(0,host_dead) ;
/* send a host going down message to the imp */
hw_dwn();
sleep( 5 ); /* let simmer 5 mins med. heat */
/* send a reset all hosts command to the kernel */
kw_reset( 0 );
/* tell anyone waiting on any files to go away */
for( f_p = &files[0]; f_p < &files[nfiles]; f_p++ )
if( f_p->f_state != fs_null )
{
fp = f_p;
kw_rdy( f_p->f_id,EDDWN );
kw_frlse();
}
close(k_file) ; /* close the kernel file */
}
/* name:
toggle_debug
function:
To set and reset the debugging toggles.
algorithm:
Complement the two toggles.
Reset the interrrupt
parameters:
none
returns:
nothing
globals:
k_rdebug
k_wdebug
calls:
signal (sys)
called by:
main
system in response to interrupt
history:
Initial coding by Greg Noel on 10/5/77
*/
toggle_debug()
{
k_rdebug = 1 - k_rdebug;
k_wdebug = 1 - k_wdebug;
signal(11, &toggle_debug);
}