ostool 0.31.1

A tool for operating system development
Documentation 
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//! Host boot payload shared by QEMU, U-Boot, and board runners.

use std::path::PathBuf;

use anyhow::Result;
use httpboot_protocol::valid_host_cmdline;
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};

use crate::project::variables::{self, VariableScope};

/// Optional host initramfs and kernel command line.
#[derive(Clone, Debug, Default, Deserialize, Serialize, JsonSchema, PartialEq, Eq)]
pub struct BootPayloadConfig {
    /// Path to a host initramfs archive; guest initrds are configured separately.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub initramfs: Option<String>,
    /// Boot arguments passed to the host kernel.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub cmdline: Option<String>,
}

impl BootPayloadConfig {
    pub(crate) fn replace_strings(&mut self, scope: &VariableScope) -> Result<()> {
        self.initramfs = self
            .initramfs
            .as_deref()
            .map(|path| variables::expand_variables(path, scope))
            .transpose()?;
        self.cmdline = self
            .cmdline
            .as_deref()
            .map(|value| variables::expand_variables(value, scope))
            .transpose()?;
        Ok(())
    }

    pub(crate) fn initramfs_path(&self) -> Option<PathBuf> {
        self.initramfs.as_ref().map(PathBuf::from)
    }

    pub(crate) fn validate(&self) -> Result<()> {
        anyhow::ensure!(
            self.initramfs
                .as_ref()
                .is_none_or(|path| !path.trim().is_empty()),
            "initramfs path cannot be empty"
        );
        anyhow::ensure!(
            self.cmdline
                .as_ref()
                .is_none_or(|cmdline| valid_host_cmdline(cmdline)),
            "kernel command line must be at most 4095 printable ASCII bytes"
        );
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::BootPayloadConfig;

    #[test]
    fn serializes_all_optional_payload_combinations_without_null_fields() {
        for (config, expected) in [
            (BootPayloadConfig::default(), serde_json::json!({})),
            (
                BootPayloadConfig {
                    cmdline: Some("console=ttyS0".into()),
                    initramfs: None,
                },
                serde_json::json!({"cmdline": "console=ttyS0"}),
            ),
            (
                BootPayloadConfig {
                    cmdline: None,
                    initramfs: Some("host.cpio".into()),
                },
                serde_json::json!({"initramfs": "host.cpio"}),
            ),
            (
                BootPayloadConfig {
                    cmdline: Some("console=ttyS0".into()),
                    initramfs: Some("host.cpio".into()),
                },
                serde_json::json!({
                    "cmdline": "console=ttyS0",
                    "initramfs": "host.cpio",
                }),
            ),
        ] {
            let encoded = serde_json::to_value(&config).unwrap();
            assert_eq!(encoded, expected);
            assert_eq!(
                serde_json::from_value::<BootPayloadConfig>(encoded).unwrap(),
                config
            );
        }
    }

    #[test]
    fn rejects_control_bytes_and_oversize() {
        for value in [
            "console=ttyS0\nreset".to_string(),
            "console=ttyS0\x1b".to_string(),
            "x".repeat(4096),
        ] {
            assert!(
                BootPayloadConfig {
                    cmdline: Some(value),
                    ..Default::default()
                }
                .validate()
                .is_err()
            );
        }
        assert!(
            BootPayloadConfig {
                cmdline: Some("rdinit=\"/sbin/my init\" -- arg".into()),
                ..Default::default()
            }
            .validate()
            .is_ok()
        );
        assert!(
            BootPayloadConfig {
                cmdline: Some("value='literal'".into()),
                ..Default::default()
            }
            .validate()
            .is_ok()
        );
        assert!(
            BootPayloadConfig {
                cmdline: Some(String::new()),
                ..Default::default()
            }
            .validate()
            .is_ok()
        );
    }
}