fix(tests): make integ tests pass clippy

Fix multiple clippy warnings on the rust integ tests so that we can run
clippy without errors on them.
cast_* and undocumented_unsafe_blocks are allowed in test and bench code
for convenience.

Signed-off-by: Riccardo Mancini <[email protected]>

Author: Manciukic

src/clippy-tracing/tests/integration_tests.rs

@@ -1,6 +1,9 @@
 // Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+// Allow test functions outside of test modules
+#![allow(clippy::tests_outside_test_module)]
+
 use std::fs::{OpenOptions, remove_file};
 use std::io::{Read, Write};
 use std::process::Command;
@@ -14,6 +17,7 @@ fn setup(text: &str) -> String {
     let path = format!("/tmp/{id}.rs");
     let mut file = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .read(false)
         .write(true)
         .open(&path)
@@ -203,6 +207,7 @@ fn exclude() {
 
     let mut file_one = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .read(false)
         .write(true)
         .open(&file_path_one)
@@ -211,6 +216,7 @@ fn exclude() {
 
     let mut file_two = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .read(false)
         .write(true)
         .open(&file_path_two)

src/firecracker/examples/seccomp/harmless.rs

@@ -1,6 +1,8 @@
 // Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 fn main() {
+    // SAFETY: This is just an example to demonstrate syscall filtering.
+    // The syscall is safe because we're only writing a static string to a file descriptor.
     unsafe {
         // Harmless print to standard output.
         libc::syscall(libc::SYS_write, libc::STDOUT_FILENO, "Hello, world!\n", 14);

src/firecracker/examples/seccomp/malicious.rs

@@ -1,6 +1,8 @@
 // Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 fn main() {
+    // SAFETY: This is just an example to demonstrate syscall filtering.
+    // The syscall is safe because we're only writing a static string to a file descriptor.
     unsafe {
         // In this example, the malicious component is outputting to standard input.
         libc::syscall(libc::SYS_write, libc::STDIN_FILENO, "Hello, world!\n", 14);

src/firecracker/examples/uffd/uffd_utils.rs

@@ -1,8 +1,13 @@
 // Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-// Not everything is used by both binaries
-#![allow(dead_code)]
+#![allow(
+    clippy::cast_possible_truncation,
+    clippy::cast_sign_loss,
+    clippy::undocumented_unsafe_blocks,
+    // Not everything is used by both binaries
+    dead_code
+)]
 
 use std::collections::{HashMap, HashSet};
 use std::ffi::c_void;
@@ -290,12 +295,9 @@ impl Runtime {
             revents: 0,
         });
 
-        // We can skip polling on stream fd if
-        // the connection is closed.
-        let mut skip_stream: usize = 0;
         loop {
-            let pollfd_ptr = pollfds[skip_stream..].as_mut_ptr();
-            let pollfd_size = pollfds[skip_stream..].len() as u64;
+            let pollfd_ptr = pollfds.as_mut_ptr();
+            let pollfd_size = pollfds.len() as u64;
 
             // # Safety:
             // Pollfds vector is valid
@@ -305,7 +307,7 @@ impl Runtime {
                 panic!("Could not poll for events!")
             }
 
-            for i in skip_stream..pollfds.len() {
+            for i in 0..pollfds.len() {
                 if nready == 0 {
                     break;
                 }
@@ -324,17 +326,14 @@ impl Runtime {
                             revents: 0,
                         });
                         self.uffds.insert(handler.uffd.as_raw_fd(), handler);
-
-                        // If connection is closed, we can skip the socket from being polled.
-                        if pollfds[i].revents & (libc::POLLRDHUP | libc::POLLHUP) != 0 {
-                            skip_stream = 1;
-                        }
                     } else {
                         // Handle one of uffd page faults
                         pf_event_dispatch(self.uffds.get_mut(&pollfds[i].fd).unwrap());
                     }
                 }
             }
+            // If connection is closed, we can skip the socket from being polled.
+            pollfds.retain(|pollfd| pollfd.revents & (libc::POLLRDHUP | libc::POLLHUP) == 0);
         }
     }
 }

src/firecracker/tests/verify_dependencies.rs

@@ -1,6 +1,8 @@
 // Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+#![allow(clippy::tests_outside_test_module)]
+
 use std::collections::HashMap;
 use std::fmt::Debug;
 use std::path::Path;

src/vmm/benches/memory_access.rs

@@ -1,6 +1,8 @@
 // Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+#![allow(clippy::undocumented_unsafe_blocks)]
+
 use criterion::{BatchSize, Criterion, criterion_group, criterion_main};
 use vmm::resources::VmResources;
 use vmm::vmm_config::machine_config::{HugePageConfig, MachineConfig};

src/vmm/benches/queue.rs

@@ -6,6 +6,8 @@
 //   * `Queue.add_used`
 //   * `DescriptorChain.next_descriptor`
 
+#![allow(clippy::cast_possible_truncation)]
+
 use std::num::Wrapping;
 
 use criterion::{Criterion, criterion_group, criterion_main};

src/vmm/tests/devices.rs

@@ -1,7 +1,11 @@
 // Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-#![allow(clippy::undocumented_unsafe_blocks)]
+#![allow(
+    clippy::cast_possible_truncation,
+    clippy::tests_outside_test_module,
+    clippy::undocumented_unsafe_blocks
+)]
 use std::os::raw::{c_int, c_void};
 use std::os::unix::io::{AsRawFd, RawFd};
 use std::sync::{Arc, Mutex};

src/vmm/tests/integration_tests.rs

@@ -1,6 +1,8 @@
 // Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+#![allow(clippy::cast_possible_truncation, clippy::tests_outside_test_module)]
+
 use std::io::{Seek, SeekFrom};
 use std::thread;
 use std::time::Duration;

src/vmm/tests/io_uring.rs

@@ -1,6 +1,8 @@
 // Copyright 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+#![allow(clippy::cast_possible_truncation, clippy::tests_outside_test_module)]
+
 use std::os::unix::fs::FileExt;
 use std::os::unix::io::AsRawFd;
 use std::thread;