sys/src/cmd/aux/listen1.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <auth.h>
   4
   5 int maxprocs;
   6 int verbose;
   7 int trusted;
   8
   9 void
  10 usage(void)
  11 {
  12         fprint(2, "usage: listen1 [-tv] [-p maxprocs] address cmd args...\n");
  13         exits("usage");
  14 }
  15
  16 void
  17 becomenone(void)
  18 {
  19         int fd;
  20
  21         fd = open("#c/user", OWRITE);
  22         if(fd < 0 || write(fd, "none", strlen("none")) < 0)
  23                 sysfatal("can't become none: %r");
  24         close(fd);
  25         if(newns("none", nil) < 0)
  26                 sysfatal("can't build namespace: %r");
  27 }
  28
  29 char*
  30 remoteaddr(char *dir)
  31 {
  32         static char buf[128];
  33         char *p;
  34         int n, fd;
  35
  36         snprint(buf, sizeof buf, "%s/remote", dir);
  37         fd = open(buf, OREAD);
  38         if(fd < 0)
  39                 return "";
  40         n = read(fd, buf, sizeof(buf));
  41         close(fd);
  42         if(n > 0){
  43                 buf[n] = 0;
  44                 p = strchr(buf, '!');
  45                 if(p)
  46                         *p = 0;
  47                 return buf;
  48         }
  49         return "";
  50 }
  51
  52 void
  53 main(int argc, char **argv)
  54 {
  55         char data[60], dir[40], ndir[40], wbuf[64];
  56         int ctl, nctl, fd;
  57         int wfd, nowait, procs;
  58         Dir *d;
  59
  60         ARGBEGIN{
  61         default:
  62                 usage();
  63         case 't':
  64                 trusted = 1;
  65                 break;
  66         case 'v':
  67                 verbose = 1;
  68                 break;
  69         case 'p':
  70                 maxprocs = atoi(EARGF(usage()));
  71                 break;
  72         }ARGEND
  73
  74         if(argc < 2)
  75                 usage();
  76
  77         if(!verbose){
  78                 close(1);
  79                 fd = open("/dev/null", OWRITE);
  80                 if(fd != 1){
  81                         dup(fd, 1);
  82                         close(fd);
  83                 }
  84         }
  85
  86         if(!trusted)
  87                 becomenone();
  88
  89         print("listen started\n");
  90         ctl = announce(argv[0], dir);
  91         if(ctl < 0)
  92                 sysfatal("announce %s: %r", argv[0]);
  93
  94         wfd = -1;
  95         nowait = RFNOWAIT;
  96         if(maxprocs > 0){
  97                 snprint(wbuf, sizeof(wbuf), "/proc/%d/wait", getpid());
  98                 if((wfd = open(wbuf, OREAD)) >= 0)
  99                         nowait = 0;
 100         }
 101         procs = 0;
 102         for(;;){
 103                 if(nowait == 0 && (procs >= maxprocs || (procs % 8) == 0))
 104                         while(procs > 0){
 105                                 if(procs < maxprocs){
 106                                         d = dirfstat(wfd);
 107                                         if(d == nil || d->length == 0){
 108                                                 free(d);
 109                                                 break;
 110                                         }
 111                                         free(d);
 112                                 }
 113                                 if(read(wfd, wbuf, sizeof(wbuf)) > 0)
 114                                         procs--;
 115                         }
 116
 117                 nctl = listen(dir, ndir);
 118                 if(nctl < 0)
 119                         sysfatal("listen %s: %r", argv[0]);
 120
 121                 switch(rfork(RFFDG|RFPROC|RFMEM|RFENVG|RFNAMEG|RFNOTEG|RFREND|nowait)){
 122                 case -1:
 123                         reject(nctl, ndir, "host overloaded");
 124                         close(nctl);
 125                         continue;
 126                 case 0:
 127                         fd = accept(nctl, ndir);
 128                         if(fd < 0){
 129                                 fprint(2, "accept %s: can't open  %s/data: %r\n",
 130                                         argv[0], ndir);
 131                                 _exits(0);
 132                         }
 133                         print("incoming call for %s from %s in %s\n", argv[0],
 134                                 remoteaddr(ndir), ndir);
 135                         fprint(nctl, "keepalive");
 136                         close(ctl);
 137                         close(nctl);
 138                         if(wfd >= 0)
 139                                 close(wfd);
 140                         putenv("net", ndir);
 141                         snprint(data, sizeof data, "%s/data", ndir);
 142                         bind(data, "/dev/cons", MREPL);
 143                         dup(fd, 0);
 144                         dup(fd, 1);
 145                         /* dup(fd, 2); keep stderr */
 146                         close(fd);
 147                         exec(argv[1], argv+1);
 148                         if(argv[1][0] != '/')
 149                                 exec(smprint("/bin/%s", argv[1]), argv+1);
 150                         fprint(2, "%s: exec: %r\n", argv0);
 151                         exits(nil);
 152                 default:
 153                         close(nctl);
 154                         procs++;
 155                         break;
 156                 }
 157         }
 158 }