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1// SPDX-License-Identifier: GPL-2.0
2
3use crate::helpers::*;
4use proc_macro::{token_stream, Delimiter, Literal, TokenStream, TokenTree};
5use std::fmt::Write;
6
7fn expect_string_array(it: &mut token_stream::IntoIter) -> Vec<String> {
8 let group = expect_group(it);
9 assert_eq!(group.delimiter(), Delimiter::Bracket);
10 let mut values = Vec::new();
11 let mut it = group.stream().into_iter();
12
13 while let Some(val) = try_string(&mut it) {
14 assert!(val.is_ascii(), "Expected ASCII string");
15 values.push(val);
16 match it.next() {
17 Some(TokenTree::Punct(punct)) => assert_eq!(punct.as_char(), ','),
18 None => break,
19 _ => panic!("Expected ',' or end of array"),
20 }
21 }
22 values
23}
24
25struct ModInfoBuilder<'a> {
26 module: &'a str,
27 counter: usize,
28 buffer: String,
29}
30
31impl<'a> ModInfoBuilder<'a> {
32 fn new(module: &'a str) -> Self {
33 ModInfoBuilder {
34 module,
35 counter: 0,
36 buffer: String::new(),
37 }
38 }
39
40 fn emit_base(&mut self, field: &str, content: &str, builtin: bool) {
41 let string = if builtin {
42 // Built-in modules prefix their modinfo strings by `module.`.
43 format!(
44 "{module}.{field}={content}\0",
45 module = self.module,
46 field = field,
47 content = content
48 )
49 } else {
50 // Loadable modules' modinfo strings go as-is.
51 format!("{field}={content}\0", field = field, content = content)
52 };
53
54 write!(
55 &mut self.buffer,
56 "
57 {cfg}
58 #[doc(hidden)]
59 #[link_section = \".modinfo\"]
60 #[used]
61 pub static __{module}_{counter}: [u8; {length}] = *{string};
62 ",
63 cfg = if builtin {
64 "#[cfg(not(MODULE))]"
65 } else {
66 "#[cfg(MODULE)]"
67 },
68 module = self.module.to_uppercase(),
69 counter = self.counter,
70 length = string.len(),
71 string = Literal::byte_string(string.as_bytes()),
72 )
73 .unwrap();
74
75 self.counter += 1;
76 }
77
78 fn emit_only_builtin(&mut self, field: &str, content: &str) {
79 self.emit_base(field, content, true)
80 }
81
82 fn emit_only_loadable(&mut self, field: &str, content: &str) {
83 self.emit_base(field, content, false)
84 }
85
86 fn emit(&mut self, field: &str, content: &str) {
87 self.emit_only_builtin(field, content);
88 self.emit_only_loadable(field, content);
89 }
90}
91
92#[derive(Debug, Default)]
93struct ModuleInfo {
94 type_: String,
95 license: String,
96 name: String,
97 author: Option<String>,
98 description: Option<String>,
99 alias: Option<Vec<String>>,
100}
101
102impl ModuleInfo {
103 fn parse(it: &mut token_stream::IntoIter) -> Self {
104 let mut info = ModuleInfo::default();
105
106 const EXPECTED_KEYS: &[&str] =
107 &["type", "name", "author", "description", "license", "alias"];
108 const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
109 let mut seen_keys = Vec::new();
110
111 loop {
112 let key = match it.next() {
113 Some(TokenTree::Ident(ident)) => ident.to_string(),
114 Some(_) => panic!("Expected Ident or end"),
115 None => break,
116 };
117
118 if seen_keys.contains(&key) {
119 panic!(
120 "Duplicated key \"{}\". Keys can only be specified once.",
121 key
122 );
123 }
124
125 assert_eq!(expect_punct(it), ':');
126
127 match key.as_str() {
128 "type" => info.type_ = expect_ident(it),
129 "name" => info.name = expect_string_ascii(it),
130 "author" => info.author = Some(expect_string(it)),
131 "description" => info.description = Some(expect_string(it)),
132 "license" => info.license = expect_string_ascii(it),
133 "alias" => info.alias = Some(expect_string_array(it)),
134 _ => panic!(
135 "Unknown key \"{}\". Valid keys are: {:?}.",
136 key, EXPECTED_KEYS
137 ),
138 }
139
140 assert_eq!(expect_punct(it), ',');
141
142 seen_keys.push(key);
143 }
144
145 expect_end(it);
146
147 for key in REQUIRED_KEYS {
148 if !seen_keys.iter().any(|e| e == key) {
149 panic!("Missing required key \"{}\".", key);
150 }
151 }
152
153 let mut ordered_keys: Vec<&str> = Vec::new();
154 for key in EXPECTED_KEYS {
155 if seen_keys.iter().any(|e| e == key) {
156 ordered_keys.push(key);
157 }
158 }
159
160 if seen_keys != ordered_keys {
161 panic!(
162 "Keys are not ordered as expected. Order them like: {:?}.",
163 ordered_keys
164 );
165 }
166
167 info
168 }
169}
170
171pub(crate) fn module(ts: TokenStream) -> TokenStream {
172 let mut it = ts.into_iter();
173
174 let info = ModuleInfo::parse(&mut it);
175
176 let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
177 if let Some(author) = info.author {
178 modinfo.emit("author", &author);
179 }
180 if let Some(description) = info.description {
181 modinfo.emit("description", &description);
182 }
183 modinfo.emit("license", &info.license);
184 if let Some(aliases) = info.alias {
185 for alias in aliases {
186 modinfo.emit("alias", &alias);
187 }
188 }
189
190 // Built-in modules also export the `file` modinfo string.
191 let file =
192 std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
193 modinfo.emit_only_builtin("file", &file);
194
195 format!(
196 "
197 /// The module name.
198 ///
199 /// Used by the printing macros, e.g. [`info!`].
200 const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
201
202 // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
203 // freed until the module is unloaded.
204 #[cfg(MODULE)]
205 static THIS_MODULE: kernel::ThisModule = unsafe {{
206 kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _)
207 }};
208 #[cfg(not(MODULE))]
209 static THIS_MODULE: kernel::ThisModule = unsafe {{
210 kernel::ThisModule::from_ptr(core::ptr::null_mut())
211 }};
212
213 // Double nested modules, since then nobody can access the public items inside.
214 mod __module_init {{
215 mod __module_init {{
216 use super::super::{type_};
217
218 /// The \"Rust loadable module\" mark.
219 //
220 // This may be best done another way later on, e.g. as a new modinfo
221 // key or a new section. For the moment, keep it simple.
222 #[cfg(MODULE)]
223 #[doc(hidden)]
224 #[used]
225 static __IS_RUST_MODULE: () = ();
226
227 static mut __MOD: Option<{type_}> = None;
228
229 // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
230 /// # Safety
231 ///
232 /// This function must not be called after module initialization, because it may be
233 /// freed after that completes.
234 #[cfg(MODULE)]
235 #[doc(hidden)]
236 #[no_mangle]
237 #[link_section = \".init.text\"]
238 pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{
239 // SAFETY: This function is inaccessible to the outside due to the double
240 // module wrapping it. It is called exactly once by the C side via its
241 // unique name.
242 unsafe {{ __init() }}
243 }}
244
245 #[cfg(MODULE)]
246 #[doc(hidden)]
247 #[no_mangle]
248 pub extern \"C\" fn cleanup_module() {{
249 // SAFETY:
250 // - This function is inaccessible to the outside due to the double
251 // module wrapping it. It is called exactly once by the C side via its
252 // unique name,
253 // - furthermore it is only called after `init_module` has returned `0`
254 // (which delegates to `__init`).
255 unsafe {{ __exit() }}
256 }}
257
258 // Built-in modules are initialized through an initcall pointer
259 // and the identifiers need to be unique.
260 #[cfg(not(MODULE))]
261 #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
262 #[doc(hidden)]
263 #[link_section = \"{initcall_section}\"]
264 #[used]
265 pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
266
267 #[cfg(not(MODULE))]
268 #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
269 core::arch::global_asm!(
270 r#\".section \"{initcall_section}\", \"a\"
271 __{name}_initcall:
272 .long __{name}_init - .
273 .previous
274 \"#
275 );
276
277 #[cfg(not(MODULE))]
278 #[doc(hidden)]
279 #[no_mangle]
280 pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
281 // SAFETY: This function is inaccessible to the outside due to the double
282 // module wrapping it. It is called exactly once by the C side via its
283 // placement above in the initcall section.
284 unsafe {{ __init() }}
285 }}
286
287 #[cfg(not(MODULE))]
288 #[doc(hidden)]
289 #[no_mangle]
290 pub extern \"C\" fn __{name}_exit() {{
291 // SAFETY:
292 // - This function is inaccessible to the outside due to the double
293 // module wrapping it. It is called exactly once by the C side via its
294 // unique name,
295 // - furthermore it is only called after `__{name}_init` has returned `0`
296 // (which delegates to `__init`).
297 unsafe {{ __exit() }}
298 }}
299
300 /// # Safety
301 ///
302 /// This function must only be called once.
303 unsafe fn __init() -> core::ffi::c_int {{
304 match <{type_} as kernel::Module>::init(&super::super::THIS_MODULE) {{
305 Ok(m) => {{
306 // SAFETY: No data race, since `__MOD` can only be accessed by this
307 // module and there only `__init` and `__exit` access it. These
308 // functions are only called once and `__exit` cannot be called
309 // before or during `__init`.
310 unsafe {{
311 __MOD = Some(m);
312 }}
313 return 0;
314 }}
315 Err(e) => {{
316 return e.to_errno();
317 }}
318 }}
319 }}
320
321 /// # Safety
322 ///
323 /// This function must
324 /// - only be called once,
325 /// - be called after `__init` has been called and returned `0`.
326 unsafe fn __exit() {{
327 // SAFETY: No data race, since `__MOD` can only be accessed by this module
328 // and there only `__init` and `__exit` access it. These functions are only
329 // called once and `__init` was already called.
330 unsafe {{
331 // Invokes `drop()` on `__MOD`, which should be used for cleanup.
332 __MOD = None;
333 }}
334 }}
335
336 {modinfo}
337 }}
338 }}
339 ",
340 type_ = info.type_,
341 name = info.name,
342 modinfo = modinfo.buffer,
343 initcall_section = ".initcall6.init"
344 )
345 .parse()
346 .expect("Error parsing formatted string into token stream.")
347}