20885173282

Committed 10 Jan 2026 10:13PM UTC coverage: 97.615% (+0.002%) from 97.613%

Build # 20885173282

Build Type

Pull #94

github

Committed by

web-flow

Commit Message

Merge 77312f8f8 into 3ba850701

Pull Request Pull Request #94: README: add updated readme

Coverage Stats

11 of 11 new or added lines in 2 files covered. (100.0%)

4 existing lines in 2 files now uncovered.

1228 of 1258 relevant lines covered (97.62%)

9.27 hits per line

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98.46

/src/kmsg.rs

// SPDX-License-Identifier: Apache-2.0
// Copyright (c) NVIDIA CORPORATION

use anyhow::{Context, Result};
use std::fs::{self, File, OpenOptions};
use std::sync::Once;

static KERNLOG_INIT: Once = Once::new();

/// Socket buffer size (16MB = 16 * 1024 * 1024 = 16777216 bytes).
/// Large buffers prevent message loss during high-throughput GPU operations
/// where NVIDIA drivers may emit bursts of diagnostic data.
const SOCKET_BUFFER_SIZE: &str = "16777216";

/// Initialize kernel logging and tune socket buffer sizes.
/// Large buffers (16MB) prevent message loss during high-throughput GPU operations
/// where drivers may emit bursts of diagnostic data.
pub fn kernlog_setup() -> Result<()> {
    KERNLOG_INIT.call_once(|| {
        let _ = kernlog::init();
    });
    log::set_max_level(log::LevelFilter::Off);
    for path in [
        "/proc/sys/net/core/rmem_default",
        "/proc/sys/net/core/wmem_default",
        "/proc/sys/net/core/rmem_max",
        "/proc/sys/net/core/wmem_max",
    ] {
        fs::write(path, SOCKET_BUFFER_SIZE.as_bytes()).with_context(|| format!("write {}", path))?;
    }
    Ok(())
}

/// Get a file handle for kernel message output.
/// Routes to /dev/kmsg when debug logging is enabled for visibility in dmesg,
/// otherwise /dev/null to suppress noise in production.
pub fn kmsg() -> Result<File> {
    kmsg_at(if log_enabled!(log::Level::Debug) {
        "/dev/kmsg"
    } else {
        "/dev/null"
    })
}

/// Internal: open the given path for writing. Extracted for testability.
fn kmsg_at(path: &str) -> Result<File> {
    OpenOptions::new()
        .write(true)
        .open(path)
        .with_context(|| format!("open {}", path))
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::test_utils::require_root;
    use serial_test::serial;
    use std::io::Write;
    use tempfile::NamedTempFile;

    #[test]
    fn test_kmsg_at_dev_null() {
        // /dev/null is always writable, no root needed
        let file = kmsg_at("/dev/null");
        assert!(file.is_ok());
    }

    #[test]
    fn test_kmsg_at_nonexistent() {
        let err = kmsg_at("/nonexistent/path").unwrap_err();
        // Should contain the path in the error context
        assert!(
            err.to_string().contains("/nonexistent/path"),
            "error should mention the path: {}",
            err
        );
    }

    #[test]
    fn test_kmsg_at_temp_file() {
        // Create a temp file to verify we can write to it
        let temp = NamedTempFile::new().unwrap();
        let path = temp.path().to_str().unwrap();
        let mut file = kmsg_at(path).unwrap();
        assert!(file.write_all(b"test").is_ok());
    }

    #[test]
    #[serial]
    fn test_kmsg_routes_to_dev_null_when_log_off() {
        // Default log level is Off, so kmsg() should open /dev/null
        log::set_max_level(log::LevelFilter::Off);
        let file = kmsg();
        assert!(file.is_ok());
    }

    #[test]
    #[serial]
    fn test_kmsg_routes_to_kmsg_when_debug() {
        require_root();
        // When debug is enabled, kmsg() should open /dev/kmsg
        log::set_max_level(log::LevelFilter::Debug);
        let file = kmsg();
        assert!(file.is_ok());
        log::set_max_level(log::LevelFilter::Off);
    }

    #[test]
    #[serial]
    fn test_kernlog_setup() {
        require_root();

        const PATHS: [&str; 4] = [
            "/proc/sys/net/core/rmem_default",
            "/proc/sys/net/core/wmem_default",
            "/proc/sys/net/core/rmem_max",
            "/proc/sys/net/core/wmem_max",
        ];

        // RAII guard to restore original values after test
        struct Restore(Vec<(&'static str, String)>);
        impl Drop for Restore {
            fn drop(&mut self) {
                for (path, value) in &self.0 {
                    let _ = fs::write(path, value.as_bytes());
                }
            }
        }

        let saved: Vec<_> = PATHS
            .iter()
            .filter_map(|&p| fs::read_to_string(p).ok().map(|v| (p, v)))
            .collect();
        let _restore = Restore(saved);

        assert!(kernlog_setup().is_ok());

        for &path in &PATHS {
            let v = fs::read_to_string(path).expect("should read sysctl");
            assert_eq!(v.trim(), SOCKET_BUFFER_SIZE, "sysctl {} should be {}", path, SOCKET_BUFFER_SIZE);
        }
    }
}

1	// SPDX-License-Identifier: Apache-2.0
2	// Copyright (c) NVIDIA CORPORATION
3
4	use anyhow::{Context, Result};
5	use std::fs::{self, File, OpenOptions};
6	use std::sync::Once;
7
8	static KERNLOG_INIT: Once = Once::new();
9
10	/// Socket buffer size (16MB = 16 * 1024 * 1024 = 16777216 bytes).
11	/// Large buffers prevent message loss during high-throughput GPU operations
12	/// where NVIDIA drivers may emit bursts of diagnostic data.
13	const SOCKET_BUFFER_SIZE: &str = "16777216";
14
15	/// Initialize kernel logging and tune socket buffer sizes.
16	/// Large buffers (16MB) prevent message loss during high-throughput GPU operations
17	/// where drivers may emit bursts of diagnostic data.
18	pub fn kernlog_setup() -> Result<()> {	2✔
19	KERNLOG_INIT.call_once(\|\| {	2✔
20	let _ = kernlog::init();	2✔
21	});	2✔
22	log::set_max_level(log::LevelFilter::Off);	2✔
23	for path in [	8✔
24	"/proc/sys/net/core/rmem_default",
25	"/proc/sys/net/core/wmem_default",	2✔
26	"/proc/sys/net/core/rmem_max",	2✔
27	"/proc/sys/net/core/wmem_max",	2✔
28	] {
29	fs::write(path, SOCKET_BUFFER_SIZE.as_bytes()).with_context(\|\| format!("write {}", path))?;	8✔
30	}
31	Ok(())	2✔
32	}	2✔
33
34	/// Get a file handle for kernel message output.
35	/// Routes to /dev/kmsg when debug logging is enabled for visibility in dmesg,
36	/// otherwise /dev/null to suppress noise in production.
37	pub fn kmsg() -> Result<File> {	127✔
38	kmsg_at(if log_enabled!(log::Level::Debug) {	127✔
39	"/dev/kmsg"	2✔
40	} else {
41	"/dev/null"	125✔
42	})
43	}	127✔
44
45	/// Internal: open the given path for writing. Extracted for testability.
46	fn kmsg_at(path: &str) -> Result<File> {	133✔
47	OpenOptions::new()	133✔
48	.write(true)	133✔
49	.open(path)	133✔
50	.with_context(\|\| format!("open {}", path))	133✔
51	}	133✔
52
53	#[cfg(test)]
54	mod tests {
55	use super::*;
56	use crate::test_utils::require_root;
57	use serial_test::serial;
58	use std::io::Write;
59	use tempfile::NamedTempFile;
60
61	#[test]
62	fn test_kmsg_at_dev_null() {	2✔
63	// /dev/null is always writable, no root needed
64	let file = kmsg_at("/dev/null");	2✔
65	assert!(file.is_ok());	2✔
66	}	2✔
67
68	#[test]
69	fn test_kmsg_at_nonexistent() {	2✔
70	let err = kmsg_at("/nonexistent/path").unwrap_err();	2✔
71	// Should contain the path in the error context
72	assert!(	2✔
73	err.to_string().contains("/nonexistent/path"),	2✔
UNCOV 74	"error should mention the path: {}",	×
75	err
76	);
77	}	2✔
78
79	#[test]
80	fn test_kmsg_at_temp_file() {	2✔
81	// Create a temp file to verify we can write to it
82	let temp = NamedTempFile::new().unwrap();	2✔
83	let path = temp.path().to_str().unwrap();	2✔
84	let mut file = kmsg_at(path).unwrap();	2✔
85	assert!(file.write_all(b"test").is_ok());	2✔
86	}	2✔
87
88	#[test]
89	#[serial]
90	fn test_kmsg_routes_to_dev_null_when_log_off() {	2✔
91	// Default log level is Off, so kmsg() should open /dev/null
92	log::set_max_level(log::LevelFilter::Off);	2✔
93	let file = kmsg();	2✔
94	assert!(file.is_ok());	2✔
95	}
96
97	#[test]
98	#[serial]
99	fn test_kmsg_routes_to_kmsg_when_debug() {	2✔
100	require_root();	2✔
101	// When debug is enabled, kmsg() should open /dev/kmsg
102	log::set_max_level(log::LevelFilter::Debug);	2✔
103	let file = kmsg();	2✔
104	assert!(file.is_ok());	2✔
105	log::set_max_level(log::LevelFilter::Off);	2✔
106	}
107
108	#[test]
109	#[serial]
110	fn test_kernlog_setup() {	2✔
111	require_root();	2✔
112
113	const PATHS: [&str; 4] = [
114	"/proc/sys/net/core/rmem_default",
115	"/proc/sys/net/core/wmem_default",
116	"/proc/sys/net/core/rmem_max",
117	"/proc/sys/net/core/wmem_max",
118	];
119
120	// RAII guard to restore original values after test
121	struct Restore(Vec<(&'static str, String)>);
122	impl Drop for Restore {
123	fn drop(&mut self) {	2✔
124	for (path, value) in &self.0 {	10✔
125	let _ = fs::write(path, value.as_bytes());	8✔
126	}	8✔
127	}	2✔
128	}
129
130	let saved: Vec<_> = PATHS	2✔
131	.iter()	2✔
132	.filter_map(\|&p\| fs::read_to_string(p).ok().map(\|v\| (p, v)))	8✔
133	.collect();	2✔
134	let _restore = Restore(saved);	2✔
135
136	assert!(kernlog_setup().is_ok());	2✔
137
138	for &path in &PATHS {	10✔
139	let v = fs::read_to_string(path).expect("should read sysctl");	8✔
140	assert_eq!(v.trim(), SOCKET_BUFFER_SIZE, "sysctl {} should be {}", path, SOCKET_BUFFER_SIZE);	8✔
141	}
142	}
143	}

NVIDIA / nvrc / 20885173282

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