required parameter use reference not pointer, ensure command is null-terminated

Author: yiwu0b11

flang/include/flang/Runtime/command.h

@@ -57,7 +57,7 @@ std::int32_t RTNAME(GetEnvVariable)(const Descriptor &name,
     const char *sourceFile = nullptr, int line = 0);
 
 // Calls std::system()
-void RTNAME(System)(const Descriptor *command = nullptr,
+void RTNAME(System)(const Descriptor &command,
     const Descriptor *exitstat = nullptr, const char *sourceFile = nullptr,
     int line = 0);
 }

flang/runtime/command.cpp

@@ -282,22 +282,39 @@ std::int32_t RTNAME(GetEnvVariable)(const Descriptor &name,
   return StatOk;
 }
 
-void RTNAME(System)(const Descriptor *command, const Descriptor *exitstat,
+const char *ensureNullTerminated(
+    const char *str, size_t length, Terminator &terminator) {
+  if (length < strlen(str)) {
+    char *newCmd{(char *)malloc(length + 1)};
+    if (newCmd == NULL) {
+      terminator.Crash("Command not null-terminated, memory allocation failed "
+                       "for null-terminated newCmd.");
+    }
+
+    strncpy(newCmd, str, length);
+    newCmd[length] = '\0';
+    return newCmd;
+  } else {
+    return str;
+  }
+}
+
+void RTNAME(System)(const Descriptor &command, const Descriptor *exitstat,
     const char *sourceFile, int line) {
   Terminator terminator{sourceFile, line};
 
-  if (command) {
-    RUNTIME_CHECK(terminator, IsValidCharDescriptor(command));
-    int status{std::system(command->OffsetElement())};
-    if (exitstat) {
-      RUNTIME_CHECK(terminator, IsValidIntDescriptor(exitstat));
+  const char *newCmd{ensureNullTerminated(
+      command.OffsetElement(), command.ElementBytes(), terminator)};
+  int status{std::system(newCmd)};
+
+  if (exitstat) {
+    RUNTIME_CHECK(terminator, IsValidIntDescriptor(exitstat));
 #ifdef _WIN32
-      StoreLengthToDescriptor(exitstat, status, terminator);
+    StoreLengthToDescriptor(exitstat, status, terminator);
 #else
-      int exitstatVal{WEXITSTATUS(status)};
-      StoreLengthToDescriptor(exitstat, exitstatVal, terminator);
+    int exitstatVal{WEXITSTATUS(status)};
+    StoreLengthToDescriptor(exitstat, exitstatVal, terminator);
 #endif
-    }
   }
 }
 

flang/unittests/Runtime/CommandTest.cpp

@@ -242,15 +242,15 @@ TEST_F(ZeroArguments, SystemValidCommandExitStat) {
   OwningPtr<Descriptor> command{CharDescriptor("echo hi")};
   OwningPtr<Descriptor> exitStat{EmptyIntDescriptor()};
 
-  RTNAME(System)(command.get(), exitStat.get());
+  RTNAME(System)(*command.get(), exitStat.get());
   CheckDescriptorEqInt(exitStat.get(), 0);
 }
 
 TEST_F(ZeroArguments, SystemInvalidCommandExitStat) {
   OwningPtr<Descriptor> command{CharDescriptor("InvalidCommand")};
   OwningPtr<Descriptor> exitStat{EmptyIntDescriptor()};
 
-  RTNAME(System)(command.get(), exitStat.get());
+  RTNAME(System)(*command.get(), exitStat.get());
 #ifdef _WIN32
   CheckDescriptorEqInt(exitStat.get(), 1);
 #else
@@ -260,12 +260,12 @@ TEST_F(ZeroArguments, SystemInvalidCommandExitStat) {
 
 TEST_F(ZeroArguments, SystemValidCommandOptionalExitStat) {
   OwningPtr<Descriptor> command{CharDescriptor("echo hi")};
-  EXPECT_NO_FATAL_FAILURE(RTNAME(System)(command.get(), nullptr));
+  EXPECT_NO_FATAL_FAILURE(RTNAME(System)(*command.get(), nullptr));
 }
 
 TEST_F(ZeroArguments, SystemInvalidCommandOptionalExitStat) {
   OwningPtr<Descriptor> command{CharDescriptor("InvalidCommand")};
-  EXPECT_NO_FATAL_FAILURE(RTNAME(System)(command.get(), nullptr));
+  EXPECT_NO_FATAL_FAILURE(RTNAME(System)(*command.get(), nullptr));
 }
 
 static const char *oneArgArgv[]{"aProgram", "anArgumentOfLength20"};