Plan 9 from Bell Labs’s /usr/web/sources/contrib/mycroftiv/root/sys/src/cmd/iosrv/control.c

Copyright © 2021 Plan 9 Foundation.
Distributed under the MIT License.
Download the Plan 9 distribution.


#include <u.h>
#include <libc.h>
#include <ctype.h>
#include "dat.h"
#include "fns.h"

/* listens on ctlfd for messages - hub commands are sent to parser */
void
ctlsrv(int ctlfd)
{
	char ctlbuf[SMBUF];
	char msgbuild[SMBUF];
	int cn;
	memset(msgbuild, 0, SMBUF);
	while(masterswitch != STOP){
		memset(ctlbuf, 0, SMBUF);
		cn = read(ctlfd, ctlbuf, SMBUF);
		if(cn == 0){
			print("\nzero length read on ctlfd\n");
		}
		if(cn < 0){
			print("\n\nctlfd read error!");
			sysfatal("ctl problems!");
		}
		if(strncmp(ctlbuf, "h", 1) == 0){
			if(rfork(RFPROC|RFMEM|RFNOWAIT) == 0){
				if(verbosity==UP){
					print("-hub command detected forking command parser-");
				}
				parsecmd(ctlbuf);
				if(verbosity==UP){
					print("-command handled successfully\n");
				}
				exits(nil);
			}
			continue;
		}
		if(strncmp(ctlbuf, "debug", 5) == 0){
			print("\ndebugging output on\n");
			verbosity = UP;
			continue;
		}
		if(strncmp(ctlbuf, "shut", 4) == 0){
			print("\ndebugging output off\n");
			verbosity = DOWN;
			continue;
		}
		if(strncmp(ctlbuf, "fear", 4) == 0){
			print("\nPARANOIA ACTIVATED READER SPEED LOCKED to WRITERS\n");
			paranoia = UP;
			continue;
		}
		if(strncmp(ctlbuf, "calm" ,4) == 0){
			print("\nreaders may proceed at will and the writers will follow\n");
			paranoia = DOWN;
			continue;
		}
		if(strncmp(ctlbuf, "quit", 4) == 0){
			print("\nQUITTING\n");
			for(int i=0; i < HUBNUM; i++){
				sprint(msgbuild, "h%dx", i);
				if(rfork(RFPROC|RFMEM|RFNOWAIT) == 0){
					print("\nsending command %s", msgbuild);
					parsecmd(msgbuild);
					exits(nil);
				}
				sleep(100);
			}
			masterswitch = STOP;
			continue;
		}
		print("\nunsupported control message\n");
	}
	print("\nexiting control server\n");
	return;
}

/* zeroes out a hub to prepare it for use */
void
zerohub(Hub *h)
{
	if(verbosity == UP){
		print("-zerohub target Hub is at %p-", h);
	}
	memset(h->name, 0, SMBUF);
	h->hubstate = STOP;
	h->sleeptime = sleepdefault;
	h->infdcount = 0;
	h->outfdcount = 0;
	h->inqcount = 0;
	memset(h->bucket, 0, BUCKSIZE);
	memset(h->inqsize, 0, (MAXQ * sizeof(int)));
	h->inbuckp = &h->bucket[0];
	for(int i=0; i < MAXFDS; i++){
		h->msgptr[i] = 0;
		h->outq[i] = 0;
		h->infds[i] = -1;
		h->outfds[i] = -1;
		h->infdpids[i] = 0;
		h->outfdpids[i] = 0;
		h->infdstat[i] = GO;
		h->outfdstat[i] = GO;
		if(h->wroblck[i].locked != 0){
			print("-%s wroblock[%d] not 0\n", h->name, i);
		}
	}
	if((h->iblck.locked != 0) || (h->entwrlck.locked !=0)){
		 print("-%s locks are not zero!\n", h->name);
	}
	if(verbosity == UP){
		print("-zeroed hub-");
	} 
	return;
}

/* sets up a hub with given name and input and forks initial hubsrv */
Hub*
starthub(int hnum, char *name, char *firstin)
{
	if((hnum < 0) || (hnum > HUBNUM - 1)){
		print("bad hub number!\n");
		return nil;
	}
	Hubs[hnum] = (Hub*)malloc(sizeof(Hub));
	if(verbosity == UP){
		print("\nmalloced Hub %d at %p\n", hnum, Hubs[hnum]);
	}
	zerohub(Hubs[hnum]);
	strcat(Hubs[hnum]->name, name);
	newin(Hubs[hnum], firstin);
	Hubs[hnum]->hubstate = GO;
	hubmon[hnum] = GO;
	if(rfork(RFPROC|RFMEM|RFNOWAIT|RFNOTEG) == 0){
		hubsrv(Hubs[hnum]);
		exits(nil);
	}
	return Hubs[hnum];
}

/* parsecmd is what controls almost everything after the initial startup */
/* the most important actions are starting new hubs and attaching new outputs and inputs to existing ones */
/*command format h(hub#)[ceiostfkxvyz](parameter #) */

void
parsecmd(char *ctlbuf)
{
	int h;
	int procid;
	int tmpsleep;
	int tmpnum;
	int offset;
	int cmd;
	int para;
	offset = 0;
	char cmdtmp[SMBUF];
	char hubname[SMBUF];
	memset(hubname, 0, SMBUF);
	memset(cmdtmp, 0, SMBUF);
	if(isdigit(*(ctlbuf+1))){
		h=atoi(ctlbuf+1);
	} else {
		print("hub specification needs to be numeric!\n");
		return;
	}
	if(h>9){
		offset++;
	}
	cmd = 2 + offset;
	para = 3 + offset;
	if(strncmp(ctlbuf+cmd, "t", 1) == 0){
		if(hubmon[h] != GO){
			print("-hub inactive, skipping-");
			return;
		}
		if(isdigit(*(ctlbuf+para))){
			tmpsleep = atoi(ctlbuf+para);
		} else {
			print("command error: sleeptime parameter should be a number.\n");			
			return;
		}
		print("\nsetting sleeptime on hub %d to %d\n", h, tmpsleep);
		Hubs[h]->sleeptime = tmpsleep;
		return;
	}
	if(strncmp(ctlbuf+cmd, "c", 1) ==0){
		if(hubmon[h] != GO){
			print("-hub inactive, skipping-");
			return;
		}
		print("\nclearing Hub %d message queue and log\n", h);
		qlock(&Hubs[h]->iblck);
		sleep(500);
		print("-locking entwrlck-");
		canqlock(&Hubs[h]->entwrlck);
		Hubs[h]->inqcount = 0;
		for(int i=0; i < MAXFDS; i++){
			Hubs[h]->outq[i] = 0;
			Hubs[h]->msgptr[i] = 0;
		}
		Hubs[h]->inbuckp = &Hubs[h]->bucket[0];
		qunlock(&Hubs[h]->entwrlck);
		qunlock(&Hubs[h]->iblck);
		return;
	}
	if(strncmp(ctlbuf+cmd, "s", 1) == 0){
		if(isdigit(*(ctlbuf+para))){
			tmpnum = atoi(ctlbuf+para);
		} else {
			print("command error: start hub parameter should be a number.\n");			
			return;
		}
		sprint(cmdtmp, "%s/H%din%d", dirname, h, tmpnum);
		sprint(hubname, "H%d", h);
		print("\nmaking Hub %d %s first input %s\n", h, hubname, cmdtmp);
		starthub(h, hubname, cmdtmp);
		return;
	}
	if(strncmp(ctlbuf+cmd, "o", 1) == 0){
		if(hubmon[h] != GO){
			print("-hub inactive, skipping-");
			return;
		}
		if(isdigit(*(ctlbuf+para))){
			tmpnum = atoi(ctlbuf+para);
		} else {
			print("command error: parameter should be a number.\n");			
			return;
		}
		print("\nadding new output to hub %d\n", h);
		sprint(cmdtmp, "%s/H%dout%d", dirname, h, tmpnum);
		newout(Hubs[h], cmdtmp);
		if((procid=rfork(RFPROC|RFMEM|RFNOWAIT|RFNOTEG)) == 0){
			print("-%s forked wrproc-", Hubs[h]->name);
			wrproc(Hubs[h], (Hubs[h]->outfdcount - 1), Hubs[h]->outfds[(Hubs[h]->outfdcount -1)]);
		}
		Hubs[h]->outfdpids[(Hubs[h]->outfdcount -1)] = procid;
		return;
	}
	if(strncmp(ctlbuf+cmd, "e", 1) == 0){
		if(hubmon[h] != GO){
			print("-hub inactive, skipping-");
			return;
		}
		if(isdigit(*(ctlbuf+para))){
			tmpnum = atoi(ctlbuf+para);
		} else {
			print("command error: parameter should be a number.\n");			
			return;
		}
		print("\nadding new err output to hub %d\n", h);
		sprint(cmdtmp, "%s/H%derr%d", dirname, h, tmpnum);
		newout(Hubs[h], cmdtmp);
		if((procid=rfork(RFPROC|RFMEM|RFNOWAIT|RFNOTEG)) == 0){
			print("-%s forked wrproc-", Hubs[h]->name);
			wrproc(Hubs[h], (Hubs[h]->outfdcount - 1), Hubs[h]->outfds[(Hubs[h]->outfdcount -1)]);
		}
		Hubs[h]->outfdpids[(Hubs[h]->outfdcount -1)] = procid;
		return;
	}
	if(strncmp(ctlbuf+cmd, "i", 1) == 0){
		if(hubmon[h] != GO){
			print("-hub inactive, skipping-");
			return;
		}
		if(isdigit(*(ctlbuf+para))){
			tmpnum = atoi(ctlbuf+para);
		} else {
			print("command error: add input parameter should be a number.\n");			
			return;
		}
		print("\nadding new input to hub %d\n", h);
		sprint(cmdtmp, "%s/H%din%d", dirname, h, tmpnum);
		newin(Hubs[h], cmdtmp);
		if((procid=rfork(RFPROC|RFMEM|RFNOWAIT|RFNOTEG)) == 0){
			print("-%s forked rdproc-",Hubs[h]->name);
			rdproc(Hubs[h], (Hubs[h]->infdcount - 1), Hubs[h]->infds[(Hubs[h]->infdcount - 1)]);
		}
		Hubs[h]->infdpids[(Hubs[h]->infdcount - 1)] = procid;
		return;
	}
	if(strncmp(ctlbuf+cmd, "f", 1) == 0){
		if(isdigit(*(ctlbuf+para))){
			tmpnum=atoi(ctlbuf+para);
		} else {
			print("command error: extra fd release parameter should be a number\n");
			return;
		}
		close(extrafds[tmpnum]);
		print("extrafd[%d] closed \n", tmpnum);
		return;
	}
	if(strncmp(ctlbuf+cmd, "k", 1) == 0){
		if(isdigit(*(ctlbuf+para))){
			tmpnum=atoi(ctlbuf+para);
		} else {
			print("command error: fd kill parameter should be a number\n");
			return;
		}
		Hubs[h]->outfdstat[tmpnum] = STOP;
		close(Hubs[h]->outfds[tmpnum]);
		if(Hubs[h]->wroblck[tmpnum].locked ==1){
			qunlock(&Hubs[h]->wroblck[tmpnum]);
		}
		print("H%d outfd[%d] closed\n", h, tmpnum);
		return;
	}
	if(strncmp(ctlbuf+cmd, "x", 1) == 0){
		if(hubmon[h] != GO){
			print("-hub inactive, skipping-");
			return;
		}
		print("\n\nresetting hub %d %d infds %d outfds\n", h, Hubs[h]->infdcount, Hubs[h]->outfdcount);
		for(int i=0; i < Hubs[h]->infdcount; i++){
			if(rfork(RFPROC|RFMEM|RFNOWAIT) == 0){
				Hubs[h]->infdstat[i] = STOP;
				close(Hubs[h]->infds[i]);
				sleep(100);
				sprint(cmdtmp, "h%dy%d", h, i);
				parsecmd(cmdtmp);
				sleep(100);
				exits(nil);
			}
		}
		for(int i=0; i < Hubs[h]->outfdcount; i++){
			if(rfork(RFPROC|RFMEM|RFNOWAIT) == 0){
				Hubs[h]->outfdstat[i] = STOP;
				close(Hubs[h]->outfds[i]);
				if(Hubs[h]->wroblck[i].locked == 1){
					qunlock(&Hubs[h]->wroblck[i]);
				}
				sleep(100);
				sprint(cmdtmp, "h%dz%d", h, i);
				parsecmd(cmdtmp);
				sleep(100);
				exits(nil);
			}
		}
		Hubs[h]->hubstate = STOP;
		hubmon[h] = STOP;
		if(Hubs[h]->entwrlck.locked == 1){
			qunlock(&Hubs[h]->entwrlck);
		}
		return;
	}
	if(strncmp(ctlbuf+cmd, "v", 1) == 0){
		print("\nH%d status:\n", h);
		print("sleeptime %d infdcount %d outfdcount %d inbuckp %d inqcount %d\n", Hubs[h]->sleeptime, Hubs[h]->infdcount, Hubs[h]->outfdcount, (int)Hubs[h]->inbuckp, Hubs[h]->inqcount);
		return;
	}
	if(strncmp(ctlbuf+cmd, "y", 1) == 0){
		if(isdigit(*(ctlbuf+para))){
			tmpnum=atoi(ctlbuf+para);
		} else {
			print("command error: fd kill parameter should be a number\n");
			return;
		}
		sprint(cmdtmp, "/proc/%d/note", Hubs[h]->infdpids[tmpnum]);
		tmpnum=open(cmdtmp, OWRITE);
		if(tmpnum < 0){
			print("cant open proc\n");
			return;
		}
		fprint(tmpnum, "kill\n");
		close(tmpnum);
		print("sent kill to rdproc %s\n", cmdtmp);
		return;
	}
	if(strncmp(ctlbuf+cmd, "z", 1) == 0){
		if(isdigit(*(ctlbuf+para))){
			tmpnum=atoi(ctlbuf+para);
		} else {
			print("command error: fd kill parameter should be a number\n");
			return;
		}
		sprint(cmdtmp, "/proc/%d/note", Hubs[h]->outfdpids[tmpnum]);
		tmpnum=open(cmdtmp, OWRITE);
		if(tmpnum < 0){
			print("cant open proc\n");
			return;
		}
		fprint(tmpnum, "kill\n");
		close(tmpnum);
		print("sent kill to wrproc %s\n", cmdtmp);
		return;
	}
	print("\nno command match found\n");
	return;
}

/* Hub command mnemonics:
 * t - time
 * c - clear
 * s - start
 * o - output
 * e - err
 * i - input
 * f - free held fd
 * k - kill fd
 * x - xit
 * v - view
 * y - kill rdproc
 * z - kill wrproc
 * all commands except c, x, v take a 4th numeric character of input
 * SAMPLE COMMAND: h3o3 "on Hub[3] create output file descriptor pipe labeled H3out3"
 */

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