xref: /aosp_15_r20/bootable/libbootloader/gbl/efi/src/lib.rs (revision 5225e6b173e52d2efc6bcf950c27374fd72adabc)
1 // Copyright 2023, The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 //! This EFI application implements a demo for booting Android/Fuchsia from disk. See
16 //! bootable/libbootloader/gbl/README.md for how to run the demo. See comments of
17 //! `android_boot:android_boot_demo()` and `fuchsia_boot:fuchsia_boot_demo()` for
18 //! supported/unsupported features at the moment.
19 
20 #![cfg_attr(not(test), no_std)]
21 
22 // For the `vec!` macro
23 #[macro_use]
24 extern crate alloc;
25 
26 mod efi_blocks;
27 mod error;
28 mod ops;
29 #[macro_use]
30 mod utils;
31 
32 // Currently un-testable modules.
33 //
34 // The libefi API surface is large and complex; rather than trying to mock it all out at once, we
35 // will selectively enable modules for test as they become mockable.
36 #[cfg(not(test))]
37 mod android_boot;
38 #[cfg(not(test))]
39 mod fastboot;
40 #[cfg(not(test))]
41 mod fuchsia_boot;
42 #[cfg(not(test))]
43 mod net;
44 
45 // In tests, map the `efi_mocks` module as `efi`. This allows other modules to `use crate::efi`
46 // and automatically pick up the correct one.
47 #[cfg(not(test))]
48 pub(crate) use efi;
49 #[cfg(test)]
50 pub(crate) use efi_mocks as efi;
51 
52 #[cfg(not(test))]
53 use {
54     core::fmt::Write,
55     efi::{efi_print, efi_println, EfiEntry},
56     libgbl::Result,
57     utils::loaded_image_path,
58 };
59 
60 #[cfg(not(test))]
61 enum TargetOs {
62     Android,
63     Fuchsia,
64 }
65 
66 #[cfg(not(test))]
get_target_os(entry: &EfiEntry) -> TargetOs67 fn get_target_os(entry: &EfiEntry) -> TargetOs {
68     let mut buf = [0u8; 1];
69     if entry
70         .system_table()
71         .runtime_services()
72         .get_variable(&efi::GBL_EFI_VENDOR_GUID, efi::GBL_EFI_OS_BOOT_TARGET_VARNAME, &mut buf)
73         .is_ok()
74     {
75         efi_println!(
76             entry,
77             "`{}` is set. Proceeding as Fuchsia.",
78             efi::GBL_EFI_OS_BOOT_TARGET_VARNAME
79         );
80         TargetOs::Fuchsia
81     } else if fuchsia_boot::is_fuchsia_gpt(&entry).is_ok() {
82         efi_println!(entry, "Partition layout looks like Fuchsia. Proceeding as Fuchsia");
83         TargetOs::Fuchsia
84     } else {
85         efi_println!(entry, "Proceeding as Android");
86         TargetOs::Android
87     }
88 }
89 
90 /// GBL EFI application logic entry point.
91 #[cfg(not(test))]
app_main(entry: EfiEntry) -> Result<()>92 pub fn app_main(entry: EfiEntry) -> Result<()> {
93     efi_println!(entry, "****Generic Bootloader Application****");
94     if let Ok(v) = loaded_image_path(&entry) {
95         efi_println!(entry, "Image path: {}", v);
96     }
97 
98     match get_target_os(&entry) {
99         TargetOs::Fuchsia => fuchsia_boot::fuchsia_boot_demo(entry)?,
100         TargetOs::Android => android_boot::android_boot_demo(entry)?,
101     }
102 
103     Ok(())
104 }
105