Commit | Line | Data |
---|---|---|
247b365d WAF |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | //! Printing facilities. | |
4 | //! | |
5 | //! C header: [`include/linux/printk.h`](../../../../include/linux/printk.h) | |
6 | //! | |
7 | //! Reference: <https://www.kernel.org/doc/html/latest/core-api/printk-basics.html> | |
8 | ||
9 | use core::{ | |
10 | ffi::{c_char, c_void}, | |
11 | fmt, | |
12 | }; | |
13 | ||
14 | use crate::str::RawFormatter; | |
15 | ||
16 | #[cfg(CONFIG_PRINTK)] | |
17 | use crate::bindings; | |
18 | ||
19 | // Called from `vsprintf` with format specifier `%pA`. | |
20 | #[no_mangle] | |
21 | unsafe fn rust_fmt_argument(buf: *mut c_char, end: *mut c_char, ptr: *const c_void) -> *mut c_char { | |
22 | use fmt::Write; | |
23 | // SAFETY: The C contract guarantees that `buf` is valid if it's less than `end`. | |
24 | let mut w = unsafe { RawFormatter::from_ptrs(buf.cast(), end.cast()) }; | |
25 | let _ = w.write_fmt(unsafe { *(ptr as *const fmt::Arguments<'_>) }); | |
26 | w.pos().cast() | |
27 | } | |
28 | ||
29 | /// Format strings. | |
30 | /// | |
31 | /// Public but hidden since it should only be used from public macros. | |
32 | #[doc(hidden)] | |
33 | pub mod format_strings { | |
34 | use crate::bindings; | |
35 | ||
36 | /// The length we copy from the `KERN_*` kernel prefixes. | |
37 | const LENGTH_PREFIX: usize = 2; | |
38 | ||
39 | /// The length of the fixed format strings. | |
40 | pub const LENGTH: usize = 10; | |
41 | ||
42 | /// Generates a fixed format string for the kernel's [`_printk`]. | |
43 | /// | |
44 | /// The format string is always the same for a given level, i.e. for a | |
45 | /// given `prefix`, which are the kernel's `KERN_*` constants. | |
46 | /// | |
47 | /// [`_printk`]: ../../../../include/linux/printk.h | |
48 | const fn generate(is_cont: bool, prefix: &[u8; 3]) -> [u8; LENGTH] { | |
49 | // Ensure the `KERN_*` macros are what we expect. | |
50 | assert!(prefix[0] == b'\x01'); | |
51 | if is_cont { | |
52 | assert!(prefix[1] == b'c'); | |
53 | } else { | |
54 | assert!(prefix[1] >= b'0' && prefix[1] <= b'7'); | |
55 | } | |
56 | assert!(prefix[2] == b'\x00'); | |
57 | ||
58 | let suffix: &[u8; LENGTH - LENGTH_PREFIX] = if is_cont { | |
59 | b"%pA\0\0\0\0\0" | |
60 | } else { | |
61 | b"%s: %pA\0" | |
62 | }; | |
63 | ||
64 | [ | |
65 | prefix[0], prefix[1], suffix[0], suffix[1], suffix[2], suffix[3], suffix[4], suffix[5], | |
66 | suffix[6], suffix[7], | |
67 | ] | |
68 | } | |
69 | ||
70 | // Generate the format strings at compile-time. | |
71 | // | |
72 | // This avoids the compiler generating the contents on the fly in the stack. | |
73 | // | |
74 | // Furthermore, `static` instead of `const` is used to share the strings | |
75 | // for all the kernel. | |
76 | pub static EMERG: [u8; LENGTH] = generate(false, bindings::KERN_EMERG); | |
4c7f9499 MO |
77 | pub static ALERT: [u8; LENGTH] = generate(false, bindings::KERN_ALERT); |
78 | pub static CRIT: [u8; LENGTH] = generate(false, bindings::KERN_CRIT); | |
79 | pub static ERR: [u8; LENGTH] = generate(false, bindings::KERN_ERR); | |
80 | pub static WARNING: [u8; LENGTH] = generate(false, bindings::KERN_WARNING); | |
81 | pub static NOTICE: [u8; LENGTH] = generate(false, bindings::KERN_NOTICE); | |
247b365d | 82 | pub static INFO: [u8; LENGTH] = generate(false, bindings::KERN_INFO); |
4c7f9499 | 83 | pub static DEBUG: [u8; LENGTH] = generate(false, bindings::KERN_DEBUG); |
fc6c7cac | 84 | pub static CONT: [u8; LENGTH] = generate(true, bindings::KERN_CONT); |
247b365d WAF |
85 | } |
86 | ||
87 | /// Prints a message via the kernel's [`_printk`]. | |
88 | /// | |
89 | /// Public but hidden since it should only be used from public macros. | |
90 | /// | |
91 | /// # Safety | |
92 | /// | |
93 | /// The format string must be one of the ones in [`format_strings`], and | |
94 | /// the module name must be null-terminated. | |
95 | /// | |
96 | /// [`_printk`]: ../../../../include/linux/_printk.h | |
97 | #[doc(hidden)] | |
98 | #[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))] | |
99 | pub unsafe fn call_printk( | |
100 | format_string: &[u8; format_strings::LENGTH], | |
101 | module_name: &[u8], | |
102 | args: fmt::Arguments<'_>, | |
103 | ) { | |
104 | // `_printk` does not seem to fail in any path. | |
105 | #[cfg(CONFIG_PRINTK)] | |
106 | unsafe { | |
107 | bindings::_printk( | |
108 | format_string.as_ptr() as _, | |
109 | module_name.as_ptr(), | |
110 | &args as *const _ as *const c_void, | |
111 | ); | |
112 | } | |
113 | } | |
114 | ||
fc6c7cac MO |
115 | /// Prints a message via the kernel's [`_printk`] for the `CONT` level. |
116 | /// | |
117 | /// Public but hidden since it should only be used from public macros. | |
118 | /// | |
119 | /// [`_printk`]: ../../../../include/linux/printk.h | |
120 | #[doc(hidden)] | |
121 | #[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))] | |
122 | pub fn call_printk_cont(args: fmt::Arguments<'_>) { | |
123 | // `_printk` does not seem to fail in any path. | |
124 | // | |
125 | // SAFETY: The format string is fixed. | |
126 | #[cfg(CONFIG_PRINTK)] | |
127 | unsafe { | |
128 | bindings::_printk( | |
129 | format_strings::CONT.as_ptr() as _, | |
130 | &args as *const _ as *const c_void, | |
131 | ); | |
132 | } | |
133 | } | |
134 | ||
247b365d WAF |
135 | /// Performs formatting and forwards the string to [`call_printk`]. |
136 | /// | |
137 | /// Public but hidden since it should only be used from public macros. | |
138 | #[doc(hidden)] | |
139 | #[cfg(not(testlib))] | |
140 | #[macro_export] | |
141 | #[allow(clippy::crate_in_macro_def)] | |
142 | macro_rules! print_macro ( | |
143 | // The non-continuation cases (most of them, e.g. `INFO`). | |
fc6c7cac | 144 | ($format_string:path, false, $($arg:tt)+) => ( |
6618d69a MO |
145 | // To remain sound, `arg`s must be expanded outside the `unsafe` block. |
146 | // Typically one would use a `let` binding for that; however, `format_args!` | |
147 | // takes borrows on the arguments, but does not extend the scope of temporaries. | |
148 | // Therefore, a `match` expression is used to keep them around, since | |
149 | // the scrutinee is kept until the end of the `match`. | |
150 | match format_args!($($arg)+) { | |
151 | // SAFETY: This hidden macro should only be called by the documented | |
152 | // printing macros which ensure the format string is one of the fixed | |
153 | // ones. All `__LOG_PREFIX`s are null-terminated as they are generated | |
154 | // by the `module!` proc macro or fixed values defined in a kernel | |
155 | // crate. | |
156 | args => unsafe { | |
157 | $crate::print::call_printk( | |
158 | &$format_string, | |
159 | crate::__LOG_PREFIX, | |
160 | args, | |
161 | ); | |
162 | } | |
247b365d WAF |
163 | } |
164 | ); | |
fc6c7cac MO |
165 | |
166 | // The `CONT` case. | |
167 | ($format_string:path, true, $($arg:tt)+) => ( | |
168 | $crate::print::call_printk_cont( | |
169 | format_args!($($arg)+), | |
170 | ); | |
171 | ); | |
247b365d WAF |
172 | ); |
173 | ||
174 | /// Stub for doctests | |
175 | #[cfg(testlib)] | |
176 | #[macro_export] | |
177 | macro_rules! print_macro ( | |
178 | ($format_string:path, $e:expr, $($arg:tt)+) => ( | |
179 | () | |
180 | ); | |
181 | ); | |
182 | ||
183 | // We could use a macro to generate these macros. However, doing so ends | |
184 | // up being a bit ugly: it requires the dollar token trick to escape `$` as | |
185 | // well as playing with the `doc` attribute. Furthermore, they cannot be easily | |
186 | // imported in the prelude due to [1]. So, for the moment, we just write them | |
187 | // manually, like in the C side; while keeping most of the logic in another | |
188 | // macro, i.e. [`print_macro`]. | |
189 | // | |
190 | // [1]: https://github.com/rust-lang/rust/issues/52234 | |
191 | ||
192 | /// Prints an emergency-level message (level 0). | |
193 | /// | |
194 | /// Use this level if the system is unusable. | |
195 | /// | |
196 | /// Equivalent to the kernel's [`pr_emerg`] macro. | |
197 | /// | |
198 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
199 | /// `alloc::format!` for information about the formatting syntax. | |
200 | /// | |
201 | /// [`pr_emerg`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_emerg | |
202 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
203 | /// | |
204 | /// # Examples | |
205 | /// | |
206 | /// ``` | |
207 | /// pr_emerg!("hello {}\n", "there"); | |
208 | /// ``` | |
209 | #[macro_export] | |
210 | macro_rules! pr_emerg ( | |
211 | ($($arg:tt)*) => ( | |
fc6c7cac | 212 | $crate::print_macro!($crate::print::format_strings::EMERG, false, $($arg)*) |
247b365d WAF |
213 | ) |
214 | ); | |
215 | ||
4c7f9499 MO |
216 | /// Prints an alert-level message (level 1). |
217 | /// | |
218 | /// Use this level if action must be taken immediately. | |
219 | /// | |
220 | /// Equivalent to the kernel's [`pr_alert`] macro. | |
221 | /// | |
222 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
223 | /// `alloc::format!` for information about the formatting syntax. | |
224 | /// | |
225 | /// [`pr_alert`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_alert | |
226 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
227 | /// | |
228 | /// # Examples | |
229 | /// | |
230 | /// ``` | |
231 | /// pr_alert!("hello {}\n", "there"); | |
232 | /// ``` | |
233 | #[macro_export] | |
234 | macro_rules! pr_alert ( | |
235 | ($($arg:tt)*) => ( | |
fc6c7cac | 236 | $crate::print_macro!($crate::print::format_strings::ALERT, false, $($arg)*) |
4c7f9499 MO |
237 | ) |
238 | ); | |
239 | ||
240 | /// Prints a critical-level message (level 2). | |
241 | /// | |
242 | /// Use this level for critical conditions. | |
243 | /// | |
244 | /// Equivalent to the kernel's [`pr_crit`] macro. | |
245 | /// | |
246 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
247 | /// `alloc::format!` for information about the formatting syntax. | |
248 | /// | |
249 | /// [`pr_crit`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_crit | |
250 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
251 | /// | |
252 | /// # Examples | |
253 | /// | |
254 | /// ``` | |
255 | /// pr_crit!("hello {}\n", "there"); | |
256 | /// ``` | |
257 | #[macro_export] | |
258 | macro_rules! pr_crit ( | |
259 | ($($arg:tt)*) => ( | |
fc6c7cac | 260 | $crate::print_macro!($crate::print::format_strings::CRIT, false, $($arg)*) |
4c7f9499 MO |
261 | ) |
262 | ); | |
263 | ||
264 | /// Prints an error-level message (level 3). | |
265 | /// | |
266 | /// Use this level for error conditions. | |
267 | /// | |
268 | /// Equivalent to the kernel's [`pr_err`] macro. | |
269 | /// | |
270 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
271 | /// `alloc::format!` for information about the formatting syntax. | |
272 | /// | |
273 | /// [`pr_err`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_err | |
274 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
275 | /// | |
276 | /// # Examples | |
277 | /// | |
278 | /// ``` | |
279 | /// pr_err!("hello {}\n", "there"); | |
280 | /// ``` | |
281 | #[macro_export] | |
282 | macro_rules! pr_err ( | |
283 | ($($arg:tt)*) => ( | |
fc6c7cac | 284 | $crate::print_macro!($crate::print::format_strings::ERR, false, $($arg)*) |
4c7f9499 MO |
285 | ) |
286 | ); | |
287 | ||
288 | /// Prints a warning-level message (level 4). | |
289 | /// | |
290 | /// Use this level for warning conditions. | |
291 | /// | |
292 | /// Equivalent to the kernel's [`pr_warn`] macro. | |
293 | /// | |
294 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
295 | /// `alloc::format!` for information about the formatting syntax. | |
296 | /// | |
297 | /// [`pr_warn`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_warn | |
298 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
299 | /// | |
300 | /// # Examples | |
301 | /// | |
302 | /// ``` | |
303 | /// pr_warn!("hello {}\n", "there"); | |
304 | /// ``` | |
305 | #[macro_export] | |
306 | macro_rules! pr_warn ( | |
307 | ($($arg:tt)*) => ( | |
fc6c7cac | 308 | $crate::print_macro!($crate::print::format_strings::WARNING, false, $($arg)*) |
4c7f9499 MO |
309 | ) |
310 | ); | |
311 | ||
312 | /// Prints a notice-level message (level 5). | |
313 | /// | |
314 | /// Use this level for normal but significant conditions. | |
315 | /// | |
316 | /// Equivalent to the kernel's [`pr_notice`] macro. | |
317 | /// | |
318 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
319 | /// `alloc::format!` for information about the formatting syntax. | |
320 | /// | |
321 | /// [`pr_notice`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_notice | |
322 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
323 | /// | |
324 | /// # Examples | |
325 | /// | |
326 | /// ``` | |
327 | /// pr_notice!("hello {}\n", "there"); | |
328 | /// ``` | |
329 | #[macro_export] | |
330 | macro_rules! pr_notice ( | |
331 | ($($arg:tt)*) => ( | |
fc6c7cac | 332 | $crate::print_macro!($crate::print::format_strings::NOTICE, false, $($arg)*) |
4c7f9499 MO |
333 | ) |
334 | ); | |
335 | ||
247b365d WAF |
336 | /// Prints an info-level message (level 6). |
337 | /// | |
338 | /// Use this level for informational messages. | |
339 | /// | |
340 | /// Equivalent to the kernel's [`pr_info`] macro. | |
341 | /// | |
342 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
343 | /// `alloc::format!` for information about the formatting syntax. | |
344 | /// | |
345 | /// [`pr_info`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_info | |
346 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
347 | /// | |
348 | /// # Examples | |
349 | /// | |
350 | /// ``` | |
351 | /// pr_info!("hello {}\n", "there"); | |
352 | /// ``` | |
353 | #[macro_export] | |
354 | #[doc(alias = "print")] | |
355 | macro_rules! pr_info ( | |
356 | ($($arg:tt)*) => ( | |
fc6c7cac | 357 | $crate::print_macro!($crate::print::format_strings::INFO, false, $($arg)*) |
247b365d WAF |
358 | ) |
359 | ); | |
4c7f9499 MO |
360 | |
361 | /// Prints a debug-level message (level 7). | |
362 | /// | |
363 | /// Use this level for debug messages. | |
364 | /// | |
365 | /// Equivalent to the kernel's [`pr_debug`] macro, except that it doesn't support dynamic debug | |
366 | /// yet. | |
367 | /// | |
368 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
369 | /// `alloc::format!` for information about the formatting syntax. | |
370 | /// | |
371 | /// [`pr_debug`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_debug | |
372 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
373 | /// | |
374 | /// # Examples | |
375 | /// | |
376 | /// ``` | |
377 | /// pr_debug!("hello {}\n", "there"); | |
378 | /// ``` | |
379 | #[macro_export] | |
380 | #[doc(alias = "print")] | |
381 | macro_rules! pr_debug ( | |
382 | ($($arg:tt)*) => ( | |
383 | if cfg!(debug_assertions) { | |
fc6c7cac | 384 | $crate::print_macro!($crate::print::format_strings::DEBUG, false, $($arg)*) |
4c7f9499 MO |
385 | } |
386 | ) | |
387 | ); | |
fc6c7cac MO |
388 | |
389 | /// Continues a previous log message in the same line. | |
390 | /// | |
391 | /// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]). | |
392 | /// | |
393 | /// Equivalent to the kernel's [`pr_cont`] macro. | |
394 | /// | |
395 | /// Mimics the interface of [`std::print!`]. See [`core::fmt`] and | |
396 | /// `alloc::format!` for information about the formatting syntax. | |
397 | /// | |
398 | /// [`pr_cont`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_cont | |
399 | /// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html | |
400 | /// | |
401 | /// # Examples | |
402 | /// | |
403 | /// ``` | |
404 | /// # use kernel::pr_cont; | |
405 | /// pr_info!("hello"); | |
406 | /// pr_cont!(" {}\n", "there"); | |
407 | /// ``` | |
408 | #[macro_export] | |
409 | macro_rules! pr_cont ( | |
410 | ($($arg:tt)*) => ( | |
411 | $crate::print_macro!($crate::print::format_strings::CONT, true, $($arg)*) | |
412 | ) | |
413 | ); |