fix: represent kernel cmdline as String

alioth-cli/src/boot/boot.rs

@@ -15,7 +15,6 @@
 mod config;
 
 use std::collections::HashMap;
-use std::ffi::CString;
 use std::mem;
 use std::path::{Path, PathBuf};
 
@@ -94,7 +93,7 @@ pub struct BootArgs {
 
     /// Command line to pass to the kernel, e.g. `console=ttyS0`.
     #[arg(short, long, alias = "cmd-line", value_name = "ARGS")]
-    cmdline: Option<CString>,
+    cmdline: Option<Box<str>>,
 
     /// Path to an initramfs image.
     #[arg(short, long, value_name = "PATH")]

alioth-cli/src/boot/boot_test.rs

@@ -50,7 +50,7 @@ fn test_parse_args() {
     let args = BootArgs {
         firmware: Some(Path::new("stage0.bin").into()),
         kernel: Some(Path::new("vmlinuz").into()),
-        cmdline: Some(c"console=ttyS0".into()),
+        cmdline: Some("console=ttyS0".into()),
         initramfs: Some(Path::new("initramfs.cpio").into()),
         cpu: Some("count=16,topology=id_topo".into()),
         memory: Some("size=128G,backend=anon,shared=true".into()),
@@ -119,7 +119,7 @@ fn test_parse_args() {
         payload: Payload {
             executable: Some(Executable::Linux(Path::new("vmlinuz").into())),
             initramfs: Some(Path::new("initramfs.cpio").into()),
-            cmdline: Some(c"console=ttyS0".to_owned()),
+            cmdline: Some("console=ttyS0".into()),
             firmware: Some(Path::new("stage0.bin").into()),
         },
         net: vec![
@@ -299,29 +299,29 @@ fn test_parse_mem_arg(
 #[case(
     BootArgs {
         kernel: Some(Path::new("vmlinuz").into()),
-        cmdline: Some(c"console=ttyS0".into()),
+        cmdline: Some("console=ttyS0".into()),
         initramfs: Some(Path::new("initramfs.cpio").into()),
         ..Default::default()
     },
     Payload {
         firmware: None,
         initramfs: Some(Path::new("initramfs.cpio").into()),
         executable: Some(Executable::Linux(Path::new("vmlinuz").into())),
-        cmdline: Some(c"console=ttyS0".into()),
+        cmdline: Some("console=ttyS0".into()),
     }
 )]
 #[cfg_attr(target_arch = "x86_64", case(
     BootArgs {
         pvh: Some(Path::new("vmlinux.bin").into()),
-        cmdline: Some(c"console=ttyS0".into()),
+        cmdline: Some("console=ttyS0".into()),
         initramfs: Some(Path::new("initramfs.cpio").into()),
         ..Default::default()
     },
     Payload {
         firmware: None,
         initramfs: Some(Path::new("initramfs.cpio").into()),
         executable: Some(Executable::Pvh(Path::new("vmlinux.bin").into())),
-        cmdline: Some(c"console=ttyS0".into()),
+        cmdline: Some("console=ttyS0".into()),
     }
 ))]
 fn test_parse_payload_arg(#[case] mut args: BootArgs, #[case] want: Payload) {

alioth/src/board/board_aarch64.rs

@@ -157,8 +157,8 @@ where
         }
         let mut node = Node::default();
         if let Some(cmdline) = &payload.cmdline {
-            let bytes = cmdline.as_bytes_with_nul().to_owned();
-            node.props.insert("bootargs", PropVal::Bytes(bytes));
+            let cmdline = cmdline.to_string();
+            node.props.insert("bootargs", PropVal::String(cmdline));
         }
         if let Some(initramfs_range) = &init_state.initramfs {
             node.props.insert(

alioth/src/board/board_x86_64/board_x86_64.rs

@@ -182,7 +182,7 @@ where
             dev.add_kernel_data(image).context(error::FwCfg)?;
         };
         if let Some(cmdline) = &payload.cmdline {
-            dev.add_kernel_cmdline(cmdline.to_owned());
+            dev.add_kernel_cmdline(cmdline).context(error::FwCfg)?;
         };
         if let Some(initramfs) = &payload.initramfs {
             dev.add_initramfs_data(initramfs).context(error::FwCfg)?;

alioth/src/device/fw_cfg/fw_cfg.rs

@@ -339,11 +339,15 @@ impl FwCfg {
         Ok(())
     }
 
-    pub fn add_kernel_cmdline(&mut self, s: CString) {
-        let bytes = s.into_bytes_with_nul();
+    pub fn add_kernel_cmdline(&mut self, s: &str) -> Result<()> {
+        let Ok(c_str) = CString::new(s) else {
+            return Err(ErrorKind::InvalidInput.into());
+        };
+        let bytes = c_str.into_bytes_with_nul();
         self.known_items[FW_CFG_CMDLINE_SIZE as usize] =
             FwCfgContent::Lu32((bytes.len() as u32).into());
         self.known_items[FW_CFG_CMDLINE_DATA as usize] = FwCfgContent::Bytes(bytes);
+        Ok(())
     }
 
     pub fn add_item(&mut self, item: FwCfgItem) -> Result<()> {

alioth/src/loader/linux/linux_aarch64.rs

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::ffi::CStr;
 use std::fs::File;
 use std::io::{BufReader, Read, Seek, SeekFrom};
 use std::path::Path;
@@ -47,7 +46,7 @@ pub fn load<P: AsRef<Path>>(
     memory: &RamBus,
     mem_regions: &[(u64, MemRegionEntry)],
     kernel: P,
-    _cmdline: Option<&CStr>,
+    _cmdline: Option<&str>,
     initramfs: Option<P>,
 ) -> Result<InitState> {
     let access_kernel = error::AccessFile {

alioth/src/loader/linux/linux_x86_64.rs

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::ffi::CStr;
 use std::fs::File;
 use std::io::{BufReader, Read, Seek, SeekFrom};
 use std::mem::{size_of, size_of_val};
@@ -46,7 +45,7 @@ pub fn load<P: AsRef<Path>>(
     memory: &RamBus,
     mem_regions: &[(u64, MemRegionEntry)],
     kernel: P,
-    cmdline: Option<&CStr>,
+    cmdline: Option<&str>,
     initramfs: Option<P>,
 ) -> Result<InitState, Error> {
     let mut boot_params = BootParams::new_zeroed();
@@ -104,17 +103,20 @@ pub fn load<P: AsRef<Path>>(
 
     // load cmd line
     if let Some(cmdline) = cmdline {
-        let cmdline = cmdline.to_bytes_with_nul();
-        let cmdline_limit =
-            std::cmp::min(boot_params.hdr.cmdline_size as u64, KERNEL_CMDLINE_LIMIT);
-        if cmdline.len() as u64 > cmdline_limit {
+        let bytes = cmdline.as_bytes();
+        let cmdline_limit = std::cmp::min(
+            boot_params.hdr.cmdline_size as u64 + 1,
+            KERNEL_CMDLINE_LIMIT,
+        );
+        if bytes.len() as u64 >= cmdline_limit {
             return error::CmdLineTooLong {
-                len: cmdline.len(),
-                limit: cmdline_limit,
+                len: bytes.len(),
+                limit: cmdline_limit - 1,
             }
             .fail();
         }
-        memory.write_range(KERNEL_CMDLINE_START, cmdline.len() as u64, cmdline)?;
+        memory.write_range(KERNEL_CMDLINE_START, bytes.len() as u64, bytes)?;
+        memory.write_t(KERNEL_CMDLINE_START + bytes.len() as u64, &0u8)?;
         boot_params.hdr.cmdline_ptr = KERNEL_CMDLINE_START as u32;
         boot_params.ext_cmdline_ptr = (KERNEL_CMDLINE_START >> 32) as u32;
     }

alioth/src/loader/loader.rs

@@ -21,7 +21,6 @@ pub mod linux;
 #[path = "xen/xen.rs"]
 pub mod xen;
 
-use std::ffi::CString;
 use std::ops::Range;
 use std::path::Path;
 
@@ -41,7 +40,7 @@ pub struct Payload {
     pub firmware: Option<Box<Path>>,
     pub executable: Option<Executable>,
     pub initramfs: Option<Box<Path>>,
-    pub cmdline: Option<CString>,
+    pub cmdline: Option<Box<str>>,
 }
 
 #[derive(Debug, PartialEq, Eq, Deserialize)]

alioth/src/loader/xen/xen.rs

@@ -14,7 +14,6 @@
 
 pub mod start_info;
 
-use std::ffi::CStr;
 use std::fs::File;
 use std::io::{BufReader, Read, Seek, SeekFrom};
 use std::mem::{offset_of, size_of, size_of_val};
@@ -104,7 +103,7 @@ pub fn load<P: AsRef<Path>>(
     memory: &RamBus,
     mem_regions: &[(u64, MemRegionEntry)],
     kernel: P,
-    cmdline: Option<&CStr>,
+    cmdline: Option<&str>,
     initramfs: Option<P>,
 ) -> Result<InitState> {
     let access_kernel = error::AccessFile {
@@ -203,15 +202,16 @@ pub fn load<P: AsRef<Path>>(
 
     // load cmd line
     if let Some(cmdline) = cmdline {
-        let cmdline = cmdline.to_bytes_with_nul();
-        if cmdline.len() as u64 > KERNEL_CMDLINE_LIMIT {
+        let bytes = cmdline.as_bytes();
+        if bytes.len() as u64 >= KERNEL_CMDLINE_LIMIT {
             return error::CmdLineTooLong {
-                len: cmdline.len(),
-                limit: KERNEL_CMDLINE_LIMIT,
+                len: bytes.len(),
+                limit: KERNEL_CMDLINE_LIMIT - 1,
             }
             .fail();
         }
-        memory.write_range(KERNEL_CMDLINE_START, cmdline.len() as u64, cmdline)?;
+        memory.write_range(KERNEL_CMDLINE_START, bytes.len() as u64, bytes)?;
+        memory.write_t(KERNEL_CMDLINE_START + bytes.len() as u64, &0u8)?;
         start_info_page.start_info.cmdline_paddr = KERNEL_CMDLINE_START;
     }