sys/src/cmd/os.c

   1 #include <u.h>
   2 #include <libc.h>
   3
   4 enum {
   5         Fstdin,
   6         Fstdout,
   7         Fstderr,
   8         Fwait,
   9         Fctl,
  10         Nfd,
  11 };
  12
  13 enum {
  14         Pcopyin,
  15         Pcopyout,
  16         Pcopyerr,
  17         Preadwait,
  18         Npid,
  19 };
  20
  21 char *mnt = "/mnt/term/cmd";
  22 char *dir = nil;
  23 char buf[8192];
  24 int fd[Nfd] = {-1};
  25 int pid[Npid];
  26 int nice, foreground = 1;
  27
  28 void
  29 killstdin(void)
  30 {
  31         if(pid[Pcopyin] != 0)
  32                 postnote(PNPROC, pid[Pcopyin], "kill");
  33 }
  34
  35 void
  36 killproc(void)
  37 {
  38         if(fd[Fctl] >= 0)
  39                 write(fd[Fctl], "kill", 4);
  40 }
  41
  42 int
  43 catch(void*, char *msg)
  44 {
  45         if(strcmp(msg, "interrupt") == 0
  46         || strcmp(msg, "hangup") == 0
  47         || strcmp(msg, "kill") == 0){
  48                 killproc();
  49                 return 1;
  50         }
  51         return 0;
  52 }
  53
  54 void
  55 fd01(int fd0, int fd1)
  56 {
  57         int i;
  58
  59         if(fd0 >= 0 && fd0 != 0){
  60                 if(dup(fd0, 0) < 0)
  61                         sysfatal("dup: %r");
  62         }
  63         if(fd1 >= 0 && fd1 != 1){
  64                 if(dup(fd1, 1) < 0)
  65                         sysfatal("dup: %r");
  66         }
  67         for(i = 0; i<Nfd; i++){
  68                 if(fd[i] > 2)
  69                         close(fd[i]);
  70                 if(fd[i] == fd0)
  71                         fd[i] = 0;
  72                 else if(fd[i] == fd1)
  73                         fd[i] = 1;
  74                 else
  75                         fd[i] = -1;
  76         }
  77 }
  78
  79 void
  80 copy(void)
  81 {
  82         int n;
  83
  84         while((n = read(0, buf, sizeof(buf))) > 0)
  85                 if(write(1, buf, n) != n)
  86                         break;
  87 }
  88
  89 void
  90 usage(void)
  91 {
  92         fprint(2, "%s: [ -b ] [ -m mountpoint ] [ -d dir ] [ -n ] [ -N level ] cmd [ arg... ]\n", argv0);
  93         exits("usage");
  94 }
  95
  96 void
  97 main(int argc, char **argv)
  98 {
  99         Waitmsg *w;
 100         char *s;
 101         int n;
 102
 103         quotefmtinstall();
 104
 105         ARGBEGIN {
 106         case 'b':
 107                 foreground = 0;
 108                 break;
 109         case 'm':
 110                 mnt = cleanname(EARGF(usage()));
 111                 break;
 112         case 'd':
 113                 dir = EARGF(usage());
 114                 break;
 115         case 'n':
 116                 nice = 1;
 117                 break;
 118         case 'N':
 119                 nice = atoi(EARGF(usage()));
 120                 break;
 121         default:
 122                 usage();
 123         } ARGEND;
 124
 125         if(argc < 1)
 126                 usage();
 127
 128         seprint(buf, &buf[sizeof(buf)], "%s/clone", mnt);
 129         if((fd[Fctl] = open(buf, ORDWR)) < 0)
 130                 sysfatal("open: %r");
 131         s = &buf[strlen(mnt)+1];
 132         if((n = read(fd[Fctl], s, &buf[sizeof(buf)-1]-s)) < 0)
 133                 sysfatal("read clone: %r");
 134         while(n > 0 && buf[n-1] == '\n')
 135                 n--;
 136         s += n;
 137
 138         seprint(s, &buf[sizeof(buf)], "/wait");
 139         if((fd[Fwait] = open(buf, OREAD)) < 0)
 140                 sysfatal("open: %r");
 141
 142         if(foreground){
 143                 seprint(s, &buf[sizeof(buf)], "/data");
 144                 if((fd[Fstdin] = open(buf, OWRITE)) < 0)
 145                         sysfatal("open: %r");
 146
 147                 seprint(s, &buf[sizeof(buf)], "/data");
 148                 if((fd[Fstdout] = open(buf, OREAD)) < 0)
 149                         sysfatal("open: %r");
 150
 151                 seprint(s, &buf[sizeof(buf)], "/stderr");
 152                 if((fd[Fstderr] = open(buf, OREAD)) < 0)
 153                         sysfatal("open: %r");
 154         }
 155
 156         if(dir != nil){
 157                 if(fprint(fd[Fctl], "dir %q", dir) < 0)
 158                         sysfatal("cannot change directory: %r");
 159         } else {
 160                 /*
 161                  * try to automatically change directory if we are in
 162                  * /mnt/term or /mnt/term/root, but unlike -d flag,
 163                  * do not error when the dir ctl command fails.
 164                  */
 165                 if((s = strrchr(mnt, '/')) != nil){
 166                         n = s - mnt;
 167                         dir = getwd(buf, sizeof(buf));
 168                         if(strncmp(dir, mnt, n) == 0 && (dir[n] == 0 || dir[n] == '/')){
 169                                 dir += n;
 170                                 if(strncmp(dir, "/root", 5) == 0 && (dir[5] == 0 || dir[5] == '/'))
 171                                         dir += 5;
 172                                 if(*dir == 0)
 173                                         dir = "/";
 174                                 /* hack for win32: /C:... -> C:/... */
 175                                 if(dir[1] >= 'A' && dir[1] <= 'Z' && dir[2] == ':')
 176                                         dir[0] = dir[1], dir[1] = ':', dir[2] = '/';
 177                                 fprint(fd[Fctl], "dir %q", dir);
 178                         }
 179                 }
 180         }
 181
 182         if(nice != 0)
 183                 fprint(fd[Fctl], "nice %d", nice);
 184
 185         if(foreground)
 186                 fprint(fd[Fctl], "killonclose");
 187
 188         s = seprint(buf, &buf[sizeof(buf)], "exec");
 189         while(*argv != nil){
 190                 s = seprint(s, &buf[sizeof(buf)], " %q", *argv++);
 191                 if(s >= &buf[sizeof(buf)-1])
 192                         sysfatal("too many arguments");
 193         }
 194
 195         if(write(fd[Fctl], buf, s - buf) < 0)
 196                 sysfatal("write: %r");
 197
 198         if((pid[Preadwait] = fork()) == -1)
 199                 sysfatal("fork: %r");
 200         if(pid[Preadwait] == 0){
 201                 fd01(fd[Fwait], 2);
 202                 if((n = read(0, buf, sizeof(buf)-1)) < 0)
 203                         rerrstr(buf, sizeof(buf));
 204                 else {
 205                         char *f[5];
 206
 207                         while(n > 0 && buf[n-1] == '\n')
 208                                 n--;
 209                         buf[n] = 0;
 210                         if(tokenize(buf, f, 5) == 5)
 211                                 exits(f[4]);
 212                 }
 213                 exits(buf);
 214         }
 215
 216         if(foreground){
 217                 if((pid[Pcopyerr] = fork()) == -1)
 218                         sysfatal("fork: %r");
 219                 if(pid[Pcopyerr] == 0){
 220                         fd01(fd[Fstderr], 2);
 221                         copy();
 222                         rerrstr(buf, sizeof(buf));
 223                         exits(buf);
 224                 }
 225                 if((pid[Pcopyout] = fork()) == -1)
 226                         sysfatal("fork: %r");
 227                 if(pid[Pcopyout] == 0){
 228                         fd01(fd[Fstdout], 1);
 229                         copy();
 230                         rerrstr(buf, sizeof(buf));
 231                         exits(buf);
 232                 }
 233                 if((pid[Pcopyin] = fork()) == -1)
 234                         sysfatal("fork: %r");
 235                 if(pid[Pcopyin] == 0){
 236                         fd01(0, fd[Fstdin]);
 237                         copy();
 238                         rerrstr(buf, sizeof(buf));
 239                         exits(buf);
 240                 }
 241         }
 242         fd01(fd[Fctl], 2);
 243         atexit(killstdin);
 244         atnotify(catch, 1);
 245
 246         while((w = wait()) != nil){
 247                 if((s = strstr(w->msg, ": ")) == nil)
 248                         s = w->msg;
 249                 else
 250                         s += 2;
 251                 for(n = 0; n < Npid; n++){
 252                         if(pid[n] == w->pid){
 253                                 pid[n] = 0;
 254                                 break;
 255                         }
 256                 }
 257                 if(n == Preadwait)
 258                         exits(s);
 259                 free(w);
 260         }
 261 }