496 lines
8.6 KiB
C
496 lines
8.6 KiB
C
#include <u.h>
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#include <libc.h>
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#include <auth.h>
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enum{
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Maxpath = 1024,
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Maxserv = 64,
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};
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typedef struct Announce Announce;
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struct Announce
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{
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Announce *next;
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int announced;
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char whined;
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char mark;
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char a[];
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};
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int readstr(char*, char*, char*, int);
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void dolisten(char*, int, char*, char*, long*);
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void newcall(int, char*, char*, char*);
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void error(char*);
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void scandir(char*);
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void becomenone(void);
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void listendir(char*, int);
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char listenlog[] = "listen";
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long procs;
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long maxprocs;
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int quiet;
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int immutable;
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char *proto;
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char *protodir;
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char *addr;
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Announce *announcements;
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char *namespace;
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void
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usage(void)
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{
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error("usage: aux/listen [-iq] [-d srvdir] [-t trustsrvdir] [-n namespace] [-p maxprocs]"
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" [-a addr] [proto]");
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}
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void
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main(int argc, char *argv[])
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{
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char *trustdir;
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char *servdir;
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addr = "*";
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servdir = 0;
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trustdir = 0;
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proto = "tcp";
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quiet = 0;
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immutable = 0;
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argv0 = argv[0];
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maxprocs = 0;
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ARGBEGIN{
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case 'a':
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addr = EARGF(usage());
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break;
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case 'd':
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servdir = EARGF(usage());
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break;
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case 'q':
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quiet = 1;
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break;
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case 't':
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trustdir = EARGF(usage());
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break;
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case 'n':
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namespace = EARGF(usage());
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break;
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case 'p':
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maxprocs = atoi(EARGF(usage()));
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break;
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case 'i':
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/*
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* fixed configuration, no periodic
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* rescan of the service directory.
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*/
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immutable = 1;
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break;
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default:
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usage();
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}ARGEND;
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if(!servdir && !trustdir)
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servdir = "/bin/service";
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if(servdir && strlen(servdir) + Maxserv >= Maxpath)
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error("service directory too long");
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if(trustdir && strlen(trustdir) + Maxserv >= Maxpath)
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error("trusted service directory too long");
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switch(argc){
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case 1:
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proto = argv[0];
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break;
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case 0:
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break;
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default:
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usage();
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}
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syslog(0, listenlog, "started on %s", proto);
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protodir = proto;
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proto = strrchr(proto, '/');
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if(proto == 0)
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proto = protodir;
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else
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proto++;
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listendir(servdir, 0);
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listendir(trustdir, 1);
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/* command returns */
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exits(0);
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}
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static void
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dingdong(void*, char *msg)
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{
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if(strstr(msg, "alarm") != nil)
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noted(NCONT);
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noted(NDFLT);
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}
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void
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listendir(char *srvdir, int trusted)
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{
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int ctl, pid, start;
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char dir[40], err[128], ds[128];
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char prog[Maxpath], serv[Maxserv], ns[Maxpath];
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long childs;
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Announce *a;
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Waitmsg *wm;
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int whined;
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if (srvdir == 0)
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return;
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/*
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* insulate ourselves from later
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* changing of console environment variables
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* erase privileged crypt state
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*/
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switch(rfork(RFNOTEG|RFPROC|RFFDG|RFNOWAIT|RFENVG|RFNAMEG)) {
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case -1:
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error("fork");
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case 0:
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break;
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default:
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return;
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}
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procsetname("%s %s %s %s", protodir, addr, srvdir, namespace);
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if (!trusted)
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becomenone();
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notify(dingdong);
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pid = getpid();
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scandir(srvdir);
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for(;;){
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/*
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* loop through announcements and process trusted services in
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* invoker's ns and untrusted in none's.
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*/
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for(a = announcements; a; a = a->next){
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if(a->announced > 0)
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continue;
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sleep((pid*10)%200);
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snprint(ds, sizeof ds, "%s!%s!%s", protodir, addr, a->a);
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snprint(serv, sizeof serv, "%s%s", proto, a->a);
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snprint(prog, sizeof prog, "%s/%s", srvdir, serv);
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snprint(ns, sizeof ns, "%s.namespace", prog);
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whined = a->whined;
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/* a process per service */
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switch(pid = rfork(RFFDG|RFPROC|RFMEM)){
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case -1:
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syslog(1, listenlog, "couldn't fork for %s", ds);
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break;
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case 0:
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childs = 0;
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for(;;){
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ctl = announce(ds, dir);
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if(ctl < 0) {
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errstr(err, sizeof err);
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if (!whined)
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syslog(1, listenlog,
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"giving up on %s: %r",
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ds);
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if(strstr(err, "address in use")
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!= nil)
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exits("addr-in-use");
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else
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exits("ctl");
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}
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procsetname("%s %s", dir, ds);
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if(!trusted)
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if(newns("none", ns) < 0)
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syslog(0, listenlog, "can't build namespace %s: %r\n", ns);
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dolisten(dir, ctl, serv, prog, &childs);
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close(ctl);
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}
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default:
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a->announced = pid;
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break;
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}
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}
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/*
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* if not running a fixed configuration,
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* pick up any children that gave up and
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* sleep for at least 60 seconds.
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* If a service process dies in a fixed
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* configuration what should be done -
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* nothing? restart? restart after a delay?
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* - currently just wait for something to
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* die and delay at least 60 seconds
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* between restarts.
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*/
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start = time(0);
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if(!immutable)
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alarm(60*1000);
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while((wm = wait()) != nil) {
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for(a = announcements; a; a = a->next)
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if(a->announced == wm->pid) {
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a->announced = 0;
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if (strstr(wm->msg, "addr-in-use") !=
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nil)
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/* don't fill log file */
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a->whined = 1;
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}
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free(wm);
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if(immutable)
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break;
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}
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if(!immutable){
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alarm(0);
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scandir(srvdir);
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}
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start = 60 - (time(0)-start);
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if(start > 0)
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sleep(start*1000);
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}
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/* not reached */
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}
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/*
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* make a list of all services to announce for
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*/
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void
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addannounce(char *str)
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{
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Announce *a, **l;
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/* look for duplicate */
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l = &announcements;
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for(a = announcements; a; a = a->next){
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if(strcmp(str, a->a) == 0){
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a->mark = 0;
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return;
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}
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l = &a->next;
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}
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/* accept it */
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a = mallocz(sizeof(*a) + strlen(str) + 1, 1);
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if(a == nil)
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return;
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strcpy(a->a, str);
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*l = a;
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}
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void
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scandir(char *dname)
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{
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Announce *a, **l;
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int fd, i, n, nlen;
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char *nm;
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Dir *db;
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for(a = announcements; a != nil; a = a->next)
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a->mark = 1;
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fd = open(dname, OREAD);
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if(fd < 0)
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return;
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nlen = strlen(proto);
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while((n=dirread(fd, &db)) > 0){
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for(i=0; i<n; i++){
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nm = db[i].name;
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if(db[i].qid.type&QTDIR)
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continue;
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if(db[i].length <= 0)
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continue;
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if(strncmp(nm, proto, nlen) != 0)
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continue;
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if(strstr(nm + nlen, ".namespace") != nil)
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continue;
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addannounce(nm + nlen);
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}
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free(db);
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}
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close(fd);
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l = &announcements;
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while((a = *l) != nil){
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if(a->mark){
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*l = a->next;
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if (a->announced > 0)
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postnote(PNPROC, a->announced, "die");
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free(a);
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continue;
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}
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l = &a->next;
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}
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}
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void
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becomenone(void)
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{
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if(procsetuser("none") < 0)
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error("can't become none");
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if(newns("none", namespace) < 0)
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error("can't build namespace");
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}
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void
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dolisten(char *dir, int ctl, char *serv, char *prog, long *pchilds)
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{
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char ndir[40], wbuf[64];
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int nctl, data, wfd, nowait;
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wfd = -1;
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nowait = RFNOWAIT;
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if(pchilds && maxprocs > 0){
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snprint(wbuf, sizeof(wbuf), "/proc/%d/wait", getpid());
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if((wfd = open(wbuf, OREAD)) >= 0)
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nowait = 0;
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}
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for(;;){
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if(!nowait){
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static int hit = 0;
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Dir *d;
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/*
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* check for exited subprocesses
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*/
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if(procs >= maxprocs || (*pchilds % 8) == 0)
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while(*pchilds > 0){
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d = dirfstat(wfd);
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if(d == nil || d->length == 0){
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free(d);
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break;
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}
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free(d);
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if(read(wfd, wbuf, sizeof(wbuf)) > 0){
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adec(&procs);
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pchilds[0]--;
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}
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}
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if(procs >= maxprocs){
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if(!quiet && !hit)
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syslog(1, listenlog, "%s: process limit of %ld reached",
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proto, maxprocs);
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if(hit < 8)
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hit++;
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sleep(10<<hit);
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continue;
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}
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if(hit > 0)
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hit--;
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}
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/*
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* wait for a call (or an error)
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*/
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nctl = listen(dir, ndir);
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if(nctl < 0){
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if(!quiet)
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syslog(1, listenlog, "listen: %r");
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if(wfd >= 0)
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close(wfd);
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return;
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}
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/*
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* start a subprocess for the connection
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*/
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switch(rfork(RFFDG|RFPROC|RFMEM|RFENVG|RFNAMEG|RFNOTEG|RFREND|nowait)){
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case -1:
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reject(nctl, ndir, "host overloaded");
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close(nctl);
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continue;
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case 0:
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data = accept(nctl, ndir);
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if(data < 0){
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syslog(1, listenlog, "can't open %s/data: %r", ndir);
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exits(0);
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}
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fprint(nctl, "keepalive");
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close(ctl);
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close(nctl);
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if(wfd >= 0)
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close(wfd);
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newcall(data, ndir, prog, serv);
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exits(0);
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default:
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close(nctl);
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if(nowait)
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break;
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ainc(&procs);
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pchilds[0]++;
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break;
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}
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}
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}
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void
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newcall(int fd, char *dir, char *prog, char *serv)
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{
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char data[Maxpath];
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char remote[128];
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char *p;
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if(!quiet){
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readstr(dir, "remote", remote, sizeof remote);
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if(p = utfrune(remote, '!'))
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*p = '\0';
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syslog(0, listenlog, "%s call for %s on chan %s (%s)", proto, serv, dir, remote);
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}
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snprint(data, sizeof data, "%s/data", dir);
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bind(data, "/dev/cons", MREPL);
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dup(fd, 0);
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dup(fd, 1);
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/* dup(fd, 2); keep stderr */
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close(fd);
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/*
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* close all the fds
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*/
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for(fd=3; fd<20; fd++)
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close(fd);
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execl(prog, prog, serv, proto, dir, nil);
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error(prog);
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}
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void
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error(char *s)
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{
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syslog(1, listenlog, "%s: %s: %r", proto, s);
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exits(0);
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}
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/*
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* read a string from a device
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*/
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int
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readstr(char *dir, char *info, char *s, int len)
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{
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int n, fd;
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char buf[Maxpath];
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snprint(buf, sizeof buf, "%s/%s", dir, info);
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fd = open(buf, OREAD);
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if(fd<0)
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return 0;
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n = read(fd, s, len-1);
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if(n<=0){
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close(fd);
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return -1;
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}
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s[n] = 0;
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close(fd);
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return n+1;
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}
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