[llvm] 74a5e77 - [llvm-exegesis] Close file descriptors after use (#86584)

[via llvm-commits]

Author: Aiden Grossman
Date: 2024-04-26T02:41:21-07:00
New Revision: 74a5e7784b32aba5670ff427b158d1e6e38012f1

URL: https://github.com/llvm/llvm-project/commit/74a5e7784b32aba5670ff427b158d1e6e38012f1
DIFF: https://github.com/llvm/llvm-project/commit/74a5e7784b32aba5670ff427b158d1e6e38012f1.diff

LOG: [llvm-exegesis] Close file descriptors after use (#86584)

There are several insstances in the subprocess executor in llvm-exegesis
where we fail to close file descriptors after using them. This leaves
them open, which can cause issues later on if a third-party binary is
using the exegesis libraries and executing many blocks before exiting.
Leaving the descriptors open until process exit is also bad practice.
This patch fixes that by explicitly calling close() when we are done
with a specific file descriptor.

This patch fixes #86583.

Added: 
    

Modified: 
    llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
    llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp

Removed: 
    


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diff  --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index 498308e2edbe1f..ed53f8fabb1751 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -18,6 +18,7 @@
 #include "PerfHelper.h"
 #include "SubprocessMemory.h"
 #include "Target.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
@@ -283,6 +284,7 @@ class SubProcessFunctionExecutorImpl
                    SmallVectorImpl<int64_t> &CounterValues,
                    ArrayRef<const char *> ValidationCounters,
                    SmallVectorImpl<int64_t> &ValidationCounterValues) const {
+    auto WriteFDClose = make_scope_exit([WriteFD]() { close(WriteFD); });
     const ExegesisTarget &ET = State.getExegesisTarget();
     auto CounterOrError =
         ET.createCounter(CounterName, State, ValidationCounters, ChildPID);

diff  --git a/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp b/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp
index 1d44e09ad61e1d..cda04405050201 100644
--- a/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp
+++ b/llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp
@@ -8,6 +8,7 @@
 
 #include "SubprocessMemory.h"
 #include "Error.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FormatVariadic.h"
 #include <cerrno>
@@ -56,6 +57,8 @@ Error SubprocessMemory::initializeSubprocessMemory(pid_t ProcessID) {
     return make_error<Failure>(
         "Failed to create shared memory object for auxiliary memory: " +
         Twine(strerror(errno)));
+  auto AuxiliaryMemoryFDClose =
+      make_scope_exit([AuxiliaryMemoryFD]() { close(AuxiliaryMemoryFD); });
   if (ftruncate(AuxiliaryMemoryFD, AuxiliaryMemorySize) != 0) {
     return make_error<Failure>("Truncating the auxiliary memory failed: " +
                                Twine(strerror(errno)));
@@ -78,6 +81,8 @@ Error SubprocessMemory::addMemoryDefinition(
       return make_error<Failure>(
           "Failed to create shared memory object for memory definition: " +
           Twine(strerror(errno)));
+    auto SharedMemoryFDClose =
+        make_scope_exit([SharedMemoryFD]() { close(SharedMemoryFD); });
     if (ftruncate(SharedMemoryFD, MemVal.SizeBytes) != 0) {
       return make_error<Failure>("Truncating a memory definiton failed: " +
                                  Twine(strerror(errno)));