| 1 | //! Virtual Terminal management |
| 2 | //! |
| 3 | //! Allocates and switches VTs for X server and sessions. |
| 4 | |
| 5 | use anyhow::{Context, Result}; |
| 6 | use std::fs::OpenOptions; |
| 7 | use std::os::unix::io::AsRawFd; |
| 8 | |
| 9 | // VT ioctl constants |
| 10 | const VT_OPENQRY: libc::c_ulong = 0x5600; |
| 11 | const VT_ACTIVATE: libc::c_ulong = 0x5606; |
| 12 | const VT_WAITACTIVE: libc::c_ulong = 0x5607; |
| 13 | |
| 14 | /// Find an unused VT |
| 15 | pub fn find_unused_vt() -> Result<u32> { |
| 16 | let console = OpenOptions::new() |
| 17 | .read(true) |
| 18 | .write(true) |
| 19 | .open("/dev/tty0") |
| 20 | .context("Failed to open /dev/tty0")?; |
| 21 | |
| 22 | let mut vt: libc::c_int = 0; |
| 23 | let result = unsafe { libc::ioctl(console.as_raw_fd(), VT_OPENQRY, &mut vt) }; |
| 24 | |
| 25 | if result < 0 { |
| 26 | anyhow::bail!( |
| 27 | "VT_OPENQRY ioctl failed: {}", |
| 28 | std::io::Error::last_os_error() |
| 29 | ); |
| 30 | } |
| 31 | |
| 32 | if vt <= 0 { |
| 33 | anyhow::bail!("No unused VT available"); |
| 34 | } |
| 35 | |
| 36 | tracing::debug!("Found unused VT: {}", vt); |
| 37 | Ok(vt as u32) |
| 38 | } |
| 39 | |
| 40 | /// Switch to a specific VT |
| 41 | pub fn switch_to_vt(vt: u32) -> Result<()> { |
| 42 | let console = OpenOptions::new() |
| 43 | .read(true) |
| 44 | .write(true) |
| 45 | .open("/dev/tty0") |
| 46 | .context("Failed to open /dev/tty0")?; |
| 47 | |
| 48 | let fd = console.as_raw_fd(); |
| 49 | |
| 50 | // Activate the VT |
| 51 | let result = unsafe { libc::ioctl(fd, VT_ACTIVATE, vt as libc::c_int) }; |
| 52 | if result < 0 { |
| 53 | anyhow::bail!( |
| 54 | "VT_ACTIVATE failed for VT {}: {}", |
| 55 | vt, |
| 56 | std::io::Error::last_os_error() |
| 57 | ); |
| 58 | } |
| 59 | |
| 60 | // Wait for it to become active |
| 61 | let result = unsafe { libc::ioctl(fd, VT_WAITACTIVE, vt as libc::c_int) }; |
| 62 | if result < 0 { |
| 63 | anyhow::bail!( |
| 64 | "VT_WAITACTIVE failed for VT {}: {}", |
| 65 | vt, |
| 66 | std::io::Error::last_os_error() |
| 67 | ); |
| 68 | } |
| 69 | |
| 70 | tracing::info!("Switched to VT {}", vt); |
| 71 | Ok(()) |
| 72 | } |
| 73 | |
| 74 | /// Get the currently active VT |
| 75 | pub fn get_active_vt() -> Result<u32> { |
| 76 | #[repr(C)] |
| 77 | struct VtStat { |
| 78 | v_active: u16, |
| 79 | v_signal: u16, |
| 80 | v_state: u16, |
| 81 | } |
| 82 | |
| 83 | const VT_GETSTATE: libc::c_ulong = 0x5603; |
| 84 | |
| 85 | let console = OpenOptions::new() |
| 86 | .read(true) |
| 87 | .open("/dev/tty0") |
| 88 | .context("Failed to open /dev/tty0")?; |
| 89 | |
| 90 | let mut stat = VtStat { |
| 91 | v_active: 0, |
| 92 | v_signal: 0, |
| 93 | v_state: 0, |
| 94 | }; |
| 95 | |
| 96 | let result = unsafe { libc::ioctl(console.as_raw_fd(), VT_GETSTATE, &mut stat) }; |
| 97 | |
| 98 | if result < 0 { |
| 99 | anyhow::bail!( |
| 100 | "VT_GETSTATE failed: {}", |
| 101 | std::io::Error::last_os_error() |
| 102 | ); |
| 103 | } |
| 104 | |
| 105 | Ok(stat.v_active as u32) |
| 106 | } |
| 107 |