Add a PTY multiplexer (/dev/ptmx) device.

When you open /dev/ptmx, you get a file descriptor pointing to one of the
available MasterPTY's. If none are available, you get an EBUSY.

This makes it possible to open multiple (up to 4) Terminals. :^)

To support this, I also added a CharacterDevice::open() that gets control
when VFS is opening a CharacterDevice. This is useful when we want to return
a custom FileDescriptor like we do here.
This commit is contained in:
Andreas Kling 2019-01-16 13:36:10 +01:00
commit 9dd29f9aa9
Notes: sideshowbarker 2024-07-19 16:01:34 +09:00
13 changed files with 75 additions and 37 deletions

View file

@ -59,23 +59,13 @@ static int max(int a, int b)
return a > b ? a : b;
}
static int open_ptm()
{
char buf[32];
for (unsigned i = 0; i < 4; ++i) {
sprintf(buf, "/dev/ptm%u", i);
int fd = open(buf, O_RDWR);
if (fd)
return fd;
}
dbgprintf("No master PTY available :(\n");
exit(1);
return -1;
}
int main(int, char**)
{
int ptm_fd = open_ptm();
int ptm_fd = open("/dev/ptmx", O_RDWR);
if (ptm_fd < 0) {
perror("open(ptmx)");
return 1;
}
make_shell(ptm_fd);