1 // Copyright 2018 The Chromium OS Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #![cfg(feature = "minigbm")]
6
7 use std::ffi::CString;
8 use std::fs::{File, OpenOptions};
9
10 #[cfg(target_pointer_width = "64")]
11 use std::os::raw::c_ulong;
12 use std::os::raw::{c_char, c_int, c_uint};
13 use std::path::Path;
14 use std::ptr::null_mut;
15
16 use base::{ioctl_iowr_nr, ioctl_with_mut_ref};
17
18 use crate::rutabaga_utils::{RutabagaError, RutabagaResult};
19
20 // Consistent with __kernel_size_t in include/uapi/asm-generic/posix_types.h.
21 #[cfg(not(target_pointer_width = "64"))]
22 #[allow(non_camel_case_types)]
23 type __kernel_size_t = c_uint;
24 #[cfg(target_pointer_width = "64")]
25 #[allow(non_camel_case_types)]
26 type __kernel_size_t = c_ulong;
27
28 const DRM_IOCTL_BASE: c_uint = 0x64;
29
30 #[repr(C)]
31 #[derive(Copy, Clone)]
32 struct drm_version {
33 version_major: c_int,
34 version_minor: c_int,
35 version_patchlevel: c_int,
36 name_len: __kernel_size_t,
37 name: *mut c_char,
38 date_len: __kernel_size_t,
39 date: *mut c_char,
40 desc_len: __kernel_size_t,
41 desc: *mut c_char,
42 }
43
44 ioctl_iowr_nr!(DRM_IOCTL_VERSION, DRM_IOCTL_BASE, 0x0, drm_version);
45
get_drm_device_name(fd: &File) -> Result<String, ()>46 fn get_drm_device_name(fd: &File) -> Result<String, ()> {
47 let mut version = drm_version {
48 version_major: 0,
49 version_minor: 0,
50 version_patchlevel: 0,
51 name_len: 0,
52 name: null_mut(),
53 date_len: 0,
54 date: null_mut(),
55 desc_len: 0,
56 desc: null_mut(),
57 };
58
59 // Get the length of the device name.
60 if unsafe { ioctl_with_mut_ref(fd, DRM_IOCTL_VERSION(), &mut version) } < 0 {
61 return Err(());
62 }
63
64 // Enough bytes to hold the device name and terminating null character.
65 let mut name_bytes: Vec<u8> = vec![0; (version.name_len + 1) as usize];
66 let mut version = drm_version {
67 version_major: 0,
68 version_minor: 0,
69 version_patchlevel: 0,
70 name_len: name_bytes.len() as __kernel_size_t,
71 name: name_bytes.as_mut_ptr() as *mut c_char,
72 date_len: 0,
73 date: null_mut(),
74 desc_len: 0,
75 desc: null_mut(),
76 };
77
78 // Safe as no more than name_len + 1 bytes will be written to name.
79 if unsafe { ioctl_with_mut_ref(fd, DRM_IOCTL_VERSION(), &mut version) } < 0 {
80 return Err(());
81 }
82
83 Ok(CString::new(&name_bytes[..(version.name_len as usize)])
84 .map_err(|_| ())?
85 .into_string()
86 .map_err(|_| ())?)
87 }
88
89 /// Returns a `fd` for an opened rendernode device, while filtering out specified
90 /// undesired drivers.
open_device(undesired: &[&str]) -> RutabagaResult<File>91 pub fn open_device(undesired: &[&str]) -> RutabagaResult<File> {
92 const DRM_DIR_NAME: &str = "/dev/dri";
93 const DRM_MAX_MINOR: u32 = 15;
94 const RENDER_NODE_START: u32 = 128;
95
96 for n in RENDER_NODE_START..=RENDER_NODE_START + DRM_MAX_MINOR {
97 let path = Path::new(DRM_DIR_NAME).join(format!("renderD{}", n));
98
99 if let Ok(fd) = OpenOptions::new().read(true).write(true).open(path) {
100 if let Ok(name) = get_drm_device_name(&fd) {
101 if !undesired.iter().any(|item| *item == name) {
102 return Ok(fd);
103 }
104 }
105 }
106 }
107
108 Err(RutabagaError::Unsupported)
109 }
110