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
9int 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
49out:
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}