#include #include #include #define NAMELEN 64 /* reasonable upper limit for name elements */ typedef struct Service Service; struct Service { char serv[NAMELEN]; /* name of the service */ char remote[3*NAMELEN]; /* address of remote system */ char prog[5*NAMELEN+1]; /* program to execute */ }; typedef struct Announce Announce; struct Announce { Announce *next; char *a; int announced; }; int readstr(char*, char*, char*, int); void dolisten(char*, char*, int, char*, char*); void newcall(int, char*, char*, Service*); int findserv(char*, char*, Service*, char*); int getserv(char*, char*, Service*); void error(char*); void scandir(char*, char*, char*); void becomenone(void); void listendir(char*, char*, int); char listenlog[] = "listen"; int quiet; char *cpu; char *proto; Announce *announcements; #define SEC 1000 char *namespace; void usage(void) { error("usage: aux/listen [-q] [-d srvdir] [-t trustsrvdir] [-n namespace] [net]"); } /* * based on libthread's threadsetname, but drags in less library code. * actually just sets the arguments displayed. */ static void procsetname(char *fmt, ...) { int fd; char *cmdname; char buf[128]; va_list arg; va_start(arg, fmt); cmdname = vsmprint(fmt, arg); va_end(arg); if (cmdname == nil) return; snprint(buf, sizeof buf, "#p/%d/args", getpid()); if((fd = open(buf, OWRITE)) >= 0){ write(fd, cmdname, strlen(cmdname)+1); close(fd); } free(cmdname); } void main(int argc, char *argv[]) { Service *s; char *protodir; char *trustdir; char *servdir; servdir = 0; trustdir = 0; proto = "tcp"; quiet = 0; argv0 = argv[0]; cpu = getenv("cputype"); if(cpu == 0) error("can't get cputype"); ARGBEGIN{ case 'd': servdir = EARGF(usage()); break; case 'q': quiet = 1; break; case 't': trustdir = EARGF(usage()); break; case 'n': namespace = EARGF(usage()); break; default: usage(); }ARGEND; if(!servdir && !trustdir) servdir = "/bin/service"; if(servdir && strlen(servdir) + NAMELEN >= sizeof(s->prog)) error("service directory too long"); if(trustdir && strlen(trustdir) + NAMELEN >= sizeof(s->prog)) error("trusted service directory too long"); switch(argc){ case 1: proto = argv[0]; break; case 0: break; default: usage(); } syslog(0, listenlog, "started on %s", proto); protodir = proto; proto = strrchr(proto, '/'); if(proto == 0) proto = protodir; else proto++; listendir(protodir, servdir, 0); listendir(protodir, trustdir, 1); /* command returns */ exits(0); } static void dingdong(void*, char *msg) { if(strstr(msg, "alarm") != nil) noted(NCONT); noted(NDFLT); } void listendir(char *protodir, char *srvdir, int trusted) { int ctl, pid, start; Announce *a; char dir[40]; if (srvdir == 0) return; /* * insulate ourselves from later * changing of console environment variables * erase privileged crypt state */ switch(rfork(RFNOTEG|RFPROC|RFFDG|RFNOWAIT|RFENVG|RFNAMEG)) { case -1: error("fork"); case 0: break; default: return; } procsetname("%s %s %s", protodir, srvdir, namespace); if (!trusted) becomenone(); notify(dingdong); pid = getpid(); for(;;){ /* * loop through announcements and process trusted services in * invoker's ns and untrusted in none's. */ scandir(proto, protodir, srvdir); for(a = announcements; a; a = a->next){ if(a->announced > 0) continue; sleep((pid*10)%200); /* a process per service */ switch(pid = rfork(RFFDG|RFPROC)){ case -1: syslog(1, listenlog, "couldn't fork for %s", a->a); break; case 0: for(;;){ ctl = announce(a->a, dir); if(ctl < 0) { syslog(1, listenlog, "giving up on %s: %r", a->a); exits("ctl"); } dolisten(proto, dir, ctl, srvdir, a->a); close(ctl); } default: a->announced = pid; break; } } /* pick up any children that gave up and sleep for at least 60 seconds */ start = time(0); alarm(60*1000); while((pid = waitpid()) > 0) for(a = announcements; a; a = a->next) if(a->announced == pid) a->announced = 0; alarm(0); start = 60 - (time(0)-start); if(start > 0) sleep(start*1000); } /* not reached */ } /* * make a list of all services to announce for */ void addannounce(char *fmt, ...) { Announce *a, **l; char str[128]; va_list arg; va_start(arg, fmt); vseprint(str, str+sizeof(str), fmt, arg); va_end(arg); /* look for duplicate */ l = &announcements; for(a = announcements; a; a = a->next){ if(strcmp(str, a->a) == 0) return; l = &a->next; } /* accept it */ a = mallocz(sizeof(*a) + strlen(str) + 1, 1); if(a == 0) return; a->a = ((char*)a)+sizeof(*a); strcpy(a->a, str); a->announced = 0; *l = a; } static int ignore(char *srvdir, char *name) { int rv; char *file = smprint("%s/%s", srvdir, name); Dir *d = dirstat(file); rv = !d || d->length <= 0; /* ignore unless it's non-empty */ free(d); free(file); return rv; } void scandir(char *proto, char *protodir, char *dname) { int fd, i, n, nlen; char *nm; Dir *db; fd = open(dname, OREAD); if(fd < 0) return; nlen = strlen(proto); while((n=dirread(fd, &db)) > 0){ for(i=0; iprog, sizeof s->prog, "%s/%s", srvdir, s->serv); d = dirstat(s->prog); rv = d && d->length > 0; /* ignore unless it's non-empty */ free(d); return rv; } /* * get the service name out of the local address */ int getserv(char *proto, char *dir, Service *s) { char addr[128], *serv, *p; long n; readstr(dir, "remote", s->remote, sizeof(s->remote)-1); if(p = utfrune(s->remote, L'\n')) *p = '\0'; n = readstr(dir, "local", addr, sizeof(addr)-1); if(n <= 0) return 0; if(p = utfrune(addr, L'\n')) *p = '\0'; serv = utfrune(addr, L'!'); if(!serv) serv = "login"; else serv++; /* * disallow service names like * ../../usr/user/bin/rc/su */ if(strlen(serv) +strlen(proto) >= NAMELEN || utfrune(serv, L'/') || *serv == '.') return 0; snprint(s->serv, sizeof s->serv, "%s%s", proto, serv); return 1; } char * remoteaddr(char *dir) { char buf[128], *p; int n, fd; snprint(buf, sizeof buf, "%s/remote", dir); fd = open(buf, OREAD); if(fd < 0) return strdup(""); n = read(fd, buf, sizeof(buf)); close(fd); if(n > 0){ buf[n] = 0; p = strchr(buf, '!'); if(p) *p = 0; return strdup(buf); } return strdup(""); } void newcall(int fd, char *proto, char *dir, Service *s) { char data[4*NAMELEN]; char *p; if(!quiet){ if(dir != nil){ p = remoteaddr(dir); syslog(0, listenlog, "%s call for %s on chan %s (%s)", proto, s->serv, dir, p); free(p); } else syslog(0, listenlog, "%s call for %s on chan %s", proto, s->serv, dir); } snprint(data, sizeof data, "%s/data", dir); bind(data, "/dev/cons", MREPL); dup(fd, 0); dup(fd, 1); dup(fd, 2); close(fd); /* * close all the fds */ for(fd=3; fd<20; fd++) close(fd); execl(s->prog, s->prog, s->serv, proto, dir, nil); error(s->prog); } void error(char *s) { syslog(1, listenlog, "%s: %s: %r", proto, s); exits(0); } /* * read a string from a device */ int readstr(char *dir, char *info, char *s, int len) { int n, fd; char buf[3*NAMELEN+4]; snprint(buf, sizeof buf, "%s/%s", dir, info); fd = open(buf, OREAD); if(fd<0) return 0; n = read(fd, s, len-1); if(n<=0){ close(fd); return -1; } s[n] = 0; close(fd); return n+1; }