overhaul forkpty function using new login_tty

[oweals/musl.git] / src / misc / forkpty.c

diff --git a/src/misc/forkpty.c b/src/misc/forkpty.c
index 07f8d01eed66741e31ec3c83a07ab5d4306d2fd0..caf13adbf3f9a22aeee9d5cff4d5fe97432fb282 100644 (file)
--- a/src/misc/forkpty.c
+++ b/src/misc/forkpty.c
@@ -1,38 +1,57 @@
 #include <pty.h>
+#include <utmp.h>
 #include <unistd.h>
-#include <sys/ioctl.h>
+#include <errno.h>
 #include <fcntl.h>
+#include <sys/wait.h>
+#include <pthread.h>
 
-int forkpty(int *m, char *name, const struct termios *tio, const struct winsize *ws)
+int forkpty(int *pm, char *name, const struct termios *tio, const struct winsize *ws)
 {
-       int s, t, i, istmp[3]={0};
-       pid_t pid;
-
-       if (openpty(m, &s, name, tio, ws) < 0) return -1;
-
-       /* Ensure before forking that we don't exceed fd limit */
-       for (i=0; i<3; i++) {
-               if (fcntl(i, F_GETFL) < 0) {
-                       t = fcntl(s, F_DUPFD, i);
-                       if (t<0) break;
-                       else if (t!=i) close(t);
-                       else istmp[i] = 1;
-               }
+       int m, s, ec=0, p[2], cs;
+       pid_t pid=-1;
+       sigset_t set, oldset;
+
+       if (openpty(&m, &s, name, tio, ws) < 0) return -1;
+
+       sigfillset(&set);
+       pthread_sigmask(SIG_BLOCK, &set, &oldset);
+       pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+
+       if (pipe2(p, O_CLOEXEC)) {
+               close(s);
+               goto out;
        }
-       pid = i==3 ? fork() : -1;
+
+       pid = fork();
        if (!pid) {
-               close(*m);
-               setsid();
-               ioctl(s, TIOCSCTTY, (char *)0);
-               dup2(s, 0);
-               dup2(s, 1);
-               dup2(s, 2);
-               if (s>2) close(s);
+               close(m);
+               close(p[0]);
+               if (login_tty(s)) {
+                       write(p[1], &errno, sizeof errno);
+                       _exit(127);
+               }
+               close(p[1]);
+               pthread_setcancelstate(cs, 0);
+               pthread_sigmask(SIG_SETMASK, &oldset, 0);
                return 0;
        }
-       for (i=0; i<3; i++)
-               if (istmp[i]) close(i);
        close(s);
-       if (pid < 0) close(*m);
+       close(p[1]);
+       if (read(p[0], &ec, sizeof ec) > 0) {
+               int status;
+               waitpid(pid, &status, 0);
+               pid = -1;
+               errno = ec;
+       }
+       close(p[0]);
+
+out:
+       if (pid > 0) *pm = m;
+       else close(m);
+
+       pthread_setcancelstate(cs, 0);
+       pthread_sigmask(SIG_SETMASK, &oldset, 0);
+
        return pid;
 }