Add support for the MINIDUMP_HANDLE_DATA_STREAM to Linux

This fixes issue #92

src/bin/test.rs

@@ -247,6 +247,25 @@ mod linux {
         }
     }
 
+    fn create_files_wait(num: usize) -> Result<()> {
+        let mut file_array = Vec::<tempfile::NamedTempFile>::with_capacity(num);
+        for id in 0..num {
+            let file = tempfile::Builder::new()
+                .prefix("test_file")
+                .suffix::<str>(id.to_string().as_ref())
+                .tempfile()
+                .unwrap();
+            file_array.push(file);
+        }
+        println!("1");
+        loop {
+            std::thread::park();
+            // This shouldn't be executed, but we put it here to ensure that
+            // all the files within the array are kept open.
+            println!("{}", file_array.len());
+        }
+    }
+
     pub(super) fn real_main(args: Vec<String>) -> Result<()> {
         match args.len() {
             1 => match args[0].as_ref() {
@@ -268,6 +287,10 @@ mod linux {
                     let num_of_threads: usize = args[1].parse().unwrap();
                     spawn_name_wait(num_of_threads)
                 }
+                "create_files_wait" => {
+                    let num_of_files: usize = args[1].parse().unwrap();
+                    create_files_wait(num_of_files)
+                }
                 _ => Err(format!("Len 2: Unknown test option: {}", args[0]).into()),
             },
             3 => {

src/linux/errors.rs

@@ -142,6 +142,16 @@ pub enum SectionExceptionStreamError {
     MemoryWriterError(#[from] MemoryWriterError),
 }
 
+#[derive(Debug, Error)]
+pub enum SectionHandleDataStreamError {
+    #[error("Failed to access file")]
+    IOError(#[from] std::io::Error),
+    #[error("Failed to write to memory")]
+    MemoryWriterError(#[from] MemoryWriterError),
+    #[error("Failed integer conversion")]
+    TryFromIntError(#[from] std::num::TryFromIntError),
+}
+
 #[derive(Debug, Error)]
 pub enum SectionMappingsError {
     #[error("Failed to write to memory")]
@@ -218,6 +228,8 @@ pub enum WriterError {
     SectionAppMemoryError(#[from] SectionAppMemoryError),
     #[error("Failed when writing section ExceptionStream")]
     SectionExceptionStreamError(#[from] SectionExceptionStreamError),
+    #[error("Failed when writing section HandleDataStream")]
+    SectionHandleDataStreamError(#[from] SectionHandleDataStreamError),
     #[error("Failed when writing section MappingsError")]
     SectionMappingsError(#[from] SectionMappingsError),
     #[error("Failed when writing section MemList")]

src/linux/minidump_writer.rs

@@ -189,7 +189,7 @@ impl MinidumpWriter {
     ) -> Result<()> {
         // A minidump file contains a number of tagged streams. This is the number
         // of streams which we write.
-        let num_writers = 15u32;
+        let num_writers = 16u32;
 
         let mut header_section = MemoryWriter::<MDRawHeader>::alloc(buffer)?;
 
@@ -327,6 +327,9 @@ impl MinidumpWriter {
         // Write section to file
         dir_section.write_to_file(buffer, Some(dirent))?;
 
+        let dirent = handle_data_stream::write(self, buffer)?;
+        dir_section.write_to_file(buffer, Some(dirent))?;
+
         // If you add more directory entries, don't forget to update num_writers, above.
         Ok(())
     }

src/linux/sections.rs

@@ -1,5 +1,6 @@
 pub mod app_memory;
 pub mod exception_stream;
+pub mod handle_data_stream;
 pub mod mappings;
 pub mod memory_info_list_stream;
 pub mod memory_list_stream;

src/linux/sections/handle_data_stream.rs

@@ -0,0 +1,85 @@
+use std::{
+    ffi::{CString, OsString},
+    fs::{self, DirEntry},
+    mem::{self},
+    os::unix::prelude::OsStrExt,
+    path::{Path, PathBuf},
+};
+
+use crate::mem_writer::MemoryWriter;
+
+use super::*;
+
+fn file_stat(path: &Path) -> Option<libc::stat> {
+    let c_path = CString::new(path.as_os_str().as_bytes()).ok()?;
+    let mut stat = unsafe { std::mem::zeroed::<libc::stat>() };
+    let result = unsafe { libc::stat(c_path.as_ptr(), &mut stat) };
+
+    if result == 0 {
+        Some(stat)
+    } else {
+        None
+    }
+}
+
+fn direntry_to_descriptor(buffer: &mut DumpBuf, entry: &DirEntry) -> Option<MDRawHandleDescriptor> {
+    let handle = filename_to_fd(&entry.file_name())?;
+    let realpath = fs::read_link(entry.path()).ok()?;
+    let path_rva = write_string_to_location(buffer, realpath.to_string_lossy().as_ref()).ok()?;
+    let stat = file_stat(&entry.path())?;
+
+    // TODO: We store the contents of `st_mode` into the `attributes` field, but
+    // we could also store a human-readable string of the file type inside
+    // `type_name_rva`. We store `st_uid` inside `granted_access` but we don't
+    // store `st_gid` anywhere. We might move this missing information (and
+    // more) inside a custom `MINIDUMP_HANDLE_OBJECT_INFORMATION_TYPE` blob.
+    // That would make this conversion loss-less.
+    Some(MDRawHandleDescriptor {
+        handle,
+        type_name_rva: 0,
+        object_name_rva: path_rva.rva,
+        attributes: stat.st_mode,
+        granted_access: stat.st_uid,
+        handle_count: 0,
+        pointer_count: 0,
+    })
+}
+
+fn filename_to_fd(filename: &OsString) -> Option<u64> {
+    let filename = filename.to_string_lossy();
+    filename.parse::<u64>().ok()
+}
+
+pub fn write(
+    config: &mut MinidumpWriter,
+    buffer: &mut DumpBuf,
+) -> Result<MDRawDirectory, errors::SectionHandleDataStreamError> {
+    let proc_fd_path = PathBuf::from(format!("/proc/{}/fd", config.process_id));
+    let proc_fd_iter = fs::read_dir(proc_fd_path)?;
+    let descriptors: Vec<_> = proc_fd_iter
+        .filter_map(|entry| entry.ok())
+        .filter_map(|entry| direntry_to_descriptor(buffer, &entry))
+        .collect();
+    let number_of_descriptors = descriptors.len() as u32;
+
+    let stream_header = MemoryWriter::<MDRawHandleDataStream>::alloc_with_val(
+        buffer,
+        MDRawHandleDataStream {
+            size_of_header: mem::size_of::<MDRawHandleDataStream>() as u32,
+            size_of_descriptor: mem::size_of::<MDRawHandleDescriptor>() as u32,
+            number_of_descriptors,
+            reserved: 0,
+        },
+    )?;
+
+    let mut dirent = MDRawDirectory {
+        stream_type: MDStreamType::HandleDataStream as u32,
+        location: stream_header.location(),
+    };
+
+    let descriptor_list =
+        MemoryArrayWriter::<MDRawHandleDescriptor>::alloc_from_iter(buffer, descriptors)?;
+
+    dirent.location.data_size += descriptor_list.location().data_size;
+    Ok(dirent)
+}

src/minidump_format.rs

@@ -2,7 +2,9 @@ pub use minidump_common::format::{
     self, ArmElfHwCaps as MDCPUInformationARMElfHwCaps, PlatformId,
     ProcessorArchitecture as MDCPUArchitecture, GUID, MINIDUMP_DIRECTORY as MDRawDirectory,
     MINIDUMP_EXCEPTION as MDException, MINIDUMP_EXCEPTION_STREAM as MDRawExceptionStream,
-    MINIDUMP_HEADER as MDRawHeader, MINIDUMP_LOCATION_DESCRIPTOR as MDLocationDescriptor,
+    MINIDUMP_HANDLE_DATA_STREAM as MDRawHandleDataStream,
+    MINIDUMP_HANDLE_DESCRIPTOR as MDRawHandleDescriptor, MINIDUMP_HEADER as MDRawHeader,
+    MINIDUMP_LOCATION_DESCRIPTOR as MDLocationDescriptor,
     MINIDUMP_MEMORY_DESCRIPTOR as MDMemoryDescriptor, MINIDUMP_MEMORY_INFO as MDMemoryInfo,
     MINIDUMP_MEMORY_INFO_LIST as MDMemoryInfoList, MINIDUMP_MODULE as MDRawModule,
     MINIDUMP_SIGNATURE as MD_HEADER_SIGNATURE, MINIDUMP_STREAM_TYPE as MDStreamType,

tests/linux_minidump_writer.rs

@@ -473,6 +473,32 @@ contextual_tests! {
             expected.insert(format!("thread_{}", id));
         }
         assert_eq!(expected, names);
+
+    }
+
+    fn test_file_descriptors(context: Context) {
+        let num_of_files = 5;
+        let mut child = start_child_and_return(&["create_files_wait", num_of_files.to_string().as_ref()]);
+        let pid = child.id() as i32;
+
+        let mut tmpfile = tempfile::Builder::new()
+            .prefix("testfiles")
+            .tempfile()
+            .unwrap();
+
+        let mut tmp = context.minidump_writer(pid);
+        let _ = tmp.dump(&mut tmpfile).expect("Could not write minidump");
+        child.kill().expect("Failed to kill process");
+
+        // Reap child
+        let waitres = child.wait().expect("Failed to wait for child");
+        let status = waitres.signal().expect("Child did not die due to signal");
+        assert_eq!(waitres.code(), None);
+        assert_eq!(status, Signal::SIGKILL as i32);
+
+        // Read dump file and check its contents. There should be a truncated minidump available
+        let dump = Minidump::read_path(tmpfile.path()).expect("Failed to read minidump");
+        let fds: MinidumpHandleDataStream = dump.get_stream().expect("Couldn't find MinidumpHandleDataStream");
     }
 }