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/*
* svcfs - the control filesystem init serves.
*
* This runs in a proc of its own, sharing memory with the supervisor,
* so everything it touches is under statelock. It never starts or
* stops anything itself: a service has to be a child of the supervisor
* for the supervisor to wait for it, so a write here is validated now
* and queued for the supervisor to carry out on its next tick.
*/
#include <u.h>
#include <libc.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>
#include "dat.h"
enum
{
Qctl,
Qstatus,
Qargs,
Qpid,
Qlog,
};
typedef struct Fref Fref;
struct Fref
{
int type;
Svc *svc; /* nil for the root ctl and status */
};
static char *rootctltext =
"start <name> start a service\n"
"stop <name> stop a service\n"
"restart <name> stop it, then start it\n"
"reset stop every service, then start them again\n";
static char *svcctltext =
"start\n"
"stop\n"
"restart\n";
static Fref*
fref(int type, Svc *s)
{
Fref *f;
f = mallocz(sizeof *f, 1);
if(f == nil)
sysfatal("out of memory");
f->type = type;
f->svc = s;
return f;
}
static void
fsread(Req *r)
{
Fref *f;
char *s;
char buf[64];
int fd, n;
char path[512];
f = r->fid->file->aux;
if(f == nil){
respond(r, "not a readable file");
return;
}
switch(f->type){
case Qctl:
readstr(r, f->svc == nil ? rootctltext : svcctltext);
break;
case Qstatus:
qlock(&statelock);
s = f->svc == nil ? allstatus() : statusline(f->svc);
qunlock(&statelock);
if(s == nil){
respond(r, "out of memory");
return;
}
readstr(r, s);
free(s);
break;
case Qargs:
qlock(&statelock);
s = smprint("%s", f->svc->exec);
qunlock(&statelock);
if(s == nil){
respond(r, "out of memory");
return;
}
readstr(r, s);
free(s);
break;
case Qpid:
qlock(&statelock);
if(f->svc->pid == 0)
buf[0] = '\0';
else
snprint(buf, sizeof buf, "%d\n", f->svc->pid);
qunlock(&statelock);
readstr(r, buf);
break;
case Qlog:
snprint(path, sizeof path, "%s/%s", logdir, f->svc->name);
fd = open(path, OREAD);
if(fd < 0){
/* no output yet is not an error */
r->ofcall.count = 0;
break;
}
seek(fd, r->ifcall.offset, 0);
n = read(fd, r->ofcall.data, r->ifcall.count);
close(fd);
if(n < 0){
responderror(r);
return;
}
r->ofcall.count = n;
break;
default:
respond(r, "not a readable file");
return;
}
respond(r, nil);
}
static void
fswrite(Req *r)
{
Fref *f;
char *buf, *err;
char *fld[3];
int nf;
f = r->fid->file->aux;
if(f == nil || f->type != Qctl){
respond(r, "not a writable file");
return;
}
buf = mallocz(r->ifcall.count+1, 1);
if(buf == nil){
respond(r, "out of memory");
return;
}
memmove(buf, r->ifcall.data, r->ifcall.count);
buf[r->ifcall.count] = '\0';
nf = tokenize(buf, fld, nelem(fld));
if(nf == 0){
free(buf);
respond(r, "no command");
return;
}
if(f->svc != nil){
/*
* A per-service ctl takes no name: which file you wrote to
* already said which service you meant.
*/
if(nf != 1){
free(buf);
respond(r, "this ctl takes no arguments; "
"try start, stop or restart");
return;
}
err = queuecmd(fld[0], f->svc->name);
}else if(strcmp(fld[0], "reset") == 0)
err = queuecmd("reset", nil);
else if(nf != 2){
free(buf);
respond(r, "usage: start, stop or restart <service>, or reset");
return;
}else
err = queuecmd(fld[0], fld[1]);
free(buf);
if(err != nil){
respond(r, err);
return;
}
r->ofcall.count = r->ifcall.count;
respond(r, nil);
}
static Srv fs =
{
.read= fsread,
.write= fswrite,
};
void
startfs(char *srvname, char *mtpt)
{
Svc *s;
File *d;
Tree *t;
char *me;
/*
* Files belong to whoever is running us, so that the host owner
* can write the ctl files. They are world readable: reading a
* ctl file is how you find out what it accepts, which is no use
* if only one user may do it. Writing is what wants restricting.
*/
me = getuser();
if(me == nil)
me = "none";
t = alloctree(me, me, DMDIR|0555, nil);
if(t == nil)
sysfatal("alloctree: %r");
fs.tree = t;
createfile(t->root, "ctl", me, 0644, fref(Qctl, nil));
createfile(t->root, "status", me, 0444, fref(Qstatus, nil));
for(s = svcs; s != nil; s = s->next){
d = createfile(t->root, s->name, me, DMDIR|0555, nil);
if(d == nil){
fprint(2, "init: svcfs: create %s: %r\n", s->name);
continue;
}
createfile(d, "ctl", me, 0644, fref(Qctl, s));
createfile(d, "status", me, 0444, fref(Qstatus, s));
createfile(d, "args", me, 0444, fref(Qargs, s));
createfile(d, "pid", me, 0444, fref(Qpid, s));
createfile(d, "log", me, 0444, fref(Qlog, s));
}
postmountsrv(&fs, srvname, mtpt, MREPL);
}
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