src/misc/forkpty.c

   1 #include <pty.h>
   2 #include <utmp.h>
   3 #include <unistd.h>
   4 #include <errno.h>
   5 #include <fcntl.h>
   6 #include <sys/wait.h>
   7 #include <pthread.h>
   8
   9 int forkpty(int *pm, char *name, const struct termios *tio, const struct winsize *ws)
  10 {
  11         int m, s, ec=0, p[2], cs;
  12         pid_t pid=-1;
  13         sigset_t set, oldset;
  14
  15         if (openpty(&m, &s, name, tio, ws) < 0) return -1;
  16
  17         sigfillset(&set);
  18         pthread_sigmask(SIG_BLOCK, &set, &oldset);
  19         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  20
  21         if (pipe2(p, O_CLOEXEC)) {
  22                 close(s);
  23                 goto out;
  24         }
  25
  26         pid = fork();
  27         if (!pid) {
  28                 close(m);
  29                 close(p[0]);
  30                 if (login_tty(s)) {
  31                         write(p[1], &errno, sizeof errno);
  32                         _exit(127);
  33                 }
  34                 close(p[1]);
  35                 pthread_setcancelstate(cs, 0);
  36                 pthread_sigmask(SIG_SETMASK, &oldset, 0);
  37                 return 0;
  38         }
  39         close(s);
  40         close(p[1]);
  41         if (read(p[0], &ec, sizeof ec) > 0) {
  42                 int status;
  43                 waitpid(pid, &status, 0);
  44                 pid = -1;
  45                 errno = ec;
  46         }
  47         close(p[0]);
  48
  49 out:
  50         if (pid > 0) *pm = m;
  51         else close(m);
  52
  53         pthread_setcancelstate(cs, 0);
  54         pthread_sigmask(SIG_SETMASK, &oldset, 0);
  55
  56         return pid;
  57 }