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1// SPDX-License-Identifier: GPL-2.0
2
3use crate::helpers::*;
4use proc_macro::{token_stream, Literal, TokenStream, TokenTree};
5use std::fmt::Write;
6
7struct ModInfoBuilder<'a> {
8 module: &'a str,
9 counter: usize,
10 buffer: String,
11}
12
13impl<'a> ModInfoBuilder<'a> {
14 fn new(module: &'a str) -> Self {
15 ModInfoBuilder {
16 module,
17 counter: 0,
18 buffer: String::new(),
19 }
20 }
21
22 fn emit_base(&mut self, field: &str, content: &str, builtin: bool) {
23 let string = if builtin {
24 // Built-in modules prefix their modinfo strings by `module.`.
25 format!(
26 "{module}.{field}={content}\0",
27 module = self.module,
28 field = field,
29 content = content
30 )
31 } else {
32 // Loadable modules' modinfo strings go as-is.
33 format!("{field}={content}\0", field = field, content = content)
34 };
35
36 write!(
37 &mut self.buffer,
38 "
39 {cfg}
40 #[doc(hidden)]
41 #[link_section = \".modinfo\"]
42 #[used]
43 pub static __{module}_{counter}: [u8; {length}] = *{string};
44 ",
45 cfg = if builtin {
46 "#[cfg(not(MODULE))]"
47 } else {
48 "#[cfg(MODULE)]"
49 },
50 module = self.module.to_uppercase(),
51 counter = self.counter,
52 length = string.len(),
53 string = Literal::byte_string(string.as_bytes()),
54 )
55 .unwrap();
56
57 self.counter += 1;
58 }
59
60 fn emit_only_builtin(&mut self, field: &str, content: &str) {
61 self.emit_base(field, content, true)
62 }
63
64 fn emit_only_loadable(&mut self, field: &str, content: &str) {
65 self.emit_base(field, content, false)
66 }
67
68 fn emit(&mut self, field: &str, content: &str) {
69 self.emit_only_builtin(field, content);
70 self.emit_only_loadable(field, content);
71 }
72}
73
74#[derive(Debug, Default)]
75struct ModuleInfo {
76 type_: String,
77 license: String,
78 name: String,
79 author: Option<String>,
80 description: Option<String>,
81 alias: Option<String>,
82}
83
84impl ModuleInfo {
85 fn parse(it: &mut token_stream::IntoIter) -> Self {
86 let mut info = ModuleInfo::default();
87
88 const EXPECTED_KEYS: &[&str] =
89 &["type", "name", "author", "description", "license", "alias"];
90 const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
91 let mut seen_keys = Vec::new();
92
93 loop {
94 let key = match it.next() {
95 Some(TokenTree::Ident(ident)) => ident.to_string(),
96 Some(_) => panic!("Expected Ident or end"),
97 None => break,
98 };
99
100 if seen_keys.contains(&key) {
101 panic!(
102 "Duplicated key \"{}\". Keys can only be specified once.",
103 key
104 );
105 }
106
107 assert_eq!(expect_punct(it), ':');
108
109 match key.as_str() {
110 "type" => info.type_ = expect_ident(it),
111 "name" => info.name = expect_string_ascii(it),
112 "author" => info.author = Some(expect_string(it)),
113 "description" => info.description = Some(expect_string(it)),
114 "license" => info.license = expect_string_ascii(it),
115 "alias" => info.alias = Some(expect_string_ascii(it)),
116 _ => panic!(
117 "Unknown key \"{}\". Valid keys are: {:?}.",
118 key, EXPECTED_KEYS
119 ),
120 }
121
122 assert_eq!(expect_punct(it), ',');
123
124 seen_keys.push(key);
125 }
126
127 expect_end(it);
128
129 for key in REQUIRED_KEYS {
130 if !seen_keys.iter().any(|e| e == key) {
131 panic!("Missing required key \"{}\".", key);
132 }
133 }
134
135 let mut ordered_keys: Vec<&str> = Vec::new();
136 for key in EXPECTED_KEYS {
137 if seen_keys.iter().any(|e| e == key) {
138 ordered_keys.push(key);
139 }
140 }
141
142 if seen_keys != ordered_keys {
143 panic!(
144 "Keys are not ordered as expected. Order them like: {:?}.",
145 ordered_keys
146 );
147 }
148
149 info
150 }
151}
152
153pub(crate) fn module(ts: TokenStream) -> TokenStream {
154 let mut it = ts.into_iter();
155
156 let info = ModuleInfo::parse(&mut it);
157
158 let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
159 if let Some(author) = info.author {
160 modinfo.emit("author", &author);
161 }
162 if let Some(description) = info.description {
163 modinfo.emit("description", &description);
164 }
165 modinfo.emit("license", &info.license);
166 if let Some(alias) = info.alias {
167 modinfo.emit("alias", &alias);
168 }
169
170 // Built-in modules also export the `file` modinfo string.
171 let file =
172 std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
173 modinfo.emit_only_builtin("file", &file);
174
175 format!(
176 "
177 /// The module name.
178 ///
179 /// Used by the printing macros, e.g. [`info!`].
180 const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
181
182 /// The \"Rust loadable module\" mark, for `scripts/is_rust_module.sh`.
183 //
184 // This may be best done another way later on, e.g. as a new modinfo
185 // key or a new section. For the moment, keep it simple.
186 #[cfg(MODULE)]
187 #[doc(hidden)]
188 #[used]
189 static __IS_RUST_MODULE: () = ();
190
191 static mut __MOD: Option<{type_}> = None;
192
193 // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
194 // freed until the module is unloaded.
195 #[cfg(MODULE)]
196 static THIS_MODULE: kernel::ThisModule = unsafe {{
197 kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _)
198 }};
199 #[cfg(not(MODULE))]
200 static THIS_MODULE: kernel::ThisModule = unsafe {{
201 kernel::ThisModule::from_ptr(core::ptr::null_mut())
202 }};
203
204 // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
205 #[cfg(MODULE)]
206 #[doc(hidden)]
207 #[no_mangle]
208 pub extern \"C\" fn init_module() -> core::ffi::c_int {{
209 __init()
210 }}
211
212 #[cfg(MODULE)]
213 #[doc(hidden)]
214 #[no_mangle]
215 pub extern \"C\" fn cleanup_module() {{
216 __exit()
217 }}
218
219 // Built-in modules are initialized through an initcall pointer
220 // and the identifiers need to be unique.
221 #[cfg(not(MODULE))]
222 #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
223 #[doc(hidden)]
224 #[link_section = \"{initcall_section}\"]
225 #[used]
226 pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
227
228 #[cfg(not(MODULE))]
229 #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
230 core::arch::global_asm!(
231 r#\".section \"{initcall_section}\", \"a\"
232 __{name}_initcall:
233 .long __{name}_init - .
234 .previous
235 \"#
236 );
237
238 #[cfg(not(MODULE))]
239 #[doc(hidden)]
240 #[no_mangle]
241 pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
242 __init()
243 }}
244
245 #[cfg(not(MODULE))]
246 #[doc(hidden)]
247 #[no_mangle]
248 pub extern \"C\" fn __{name}_exit() {{
249 __exit()
250 }}
251
252 fn __init() -> core::ffi::c_int {{
253 match <{type_} as kernel::Module>::init(&THIS_MODULE) {{
254 Ok(m) => {{
255 unsafe {{
256 __MOD = Some(m);
257 }}
258 return 0;
259 }}
260 Err(e) => {{
261 return e.to_kernel_errno();
262 }}
263 }}
264 }}
265
266 fn __exit() {{
267 unsafe {{
268 // Invokes `drop()` on `__MOD`, which should be used for cleanup.
269 __MOD = None;
270 }}
271 }}
272
273 {modinfo}
274 ",
275 type_ = info.type_,
276 name = info.name,
277 modinfo = modinfo.buffer,
278 initcall_section = ".initcall6.init"
279 )
280 .parse()
281 .expect("Error parsing formatted string into token stream.")
282}