posix: Handle files that are less than the size of an elf header in exec

Dennisbonke · Jul 22, 2024 · 9f9fb3f · 9f9fb3f
1 parent b732734
commit 9f9fb3f
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Showing 4 changed files with 19 additions and 6 deletions.
diff --git a/posix/subsystem/src/file.cpp b/posix/subsystem/src/file.cpp
@@ -304,7 +304,7 @@ async::result<frg::expected<Error>> File::readExactly(Process *process,
 		auto result = FRG_CO_TRY(co_await readSome(process,
 				(char *)data + offset, length - offset));
 		if(!result)
-			co_return Error::wouldBlock;
+			co_return Error::eof;
 		offset += result;
 	}
 

diff --git a/posix/subsystem/src/file.hpp b/posix/subsystem/src/file.hpp
@@ -66,7 +66,10 @@ enum class Error {
 
 	noMemory,
 
-	directoryNotEmpty
+	directoryNotEmpty,
+
+	// Failure of the underlying device, corresponds to EIO
+	ioError
 };
 
 std::ostream& operator<<(std::ostream& os, const Error& err);

diff --git a/posix/subsystem/src/observations.cpp b/posix/subsystem/src/observations.cpp
@@ -256,20 +256,29 @@ async::result<void> observeThread(std::shared_ptr<Process> self,
 
 			auto error = co_await Process::exec(self,
 					path, std::move(args), std::move(env));
-			if(error == Error::noSuchFile) {
+			if(error == Error::success) {
+				// Continue
+			}else if(error == Error::noSuchFile) {
 				gprs[kHelRegError] = kHelErrNone;
 				gprs[kHelRegOut0] = ENOENT;
 				HEL_CHECK(helStoreRegisters(thread.getHandle(), kHelRegsGeneral, &gprs));
 
 				HEL_CHECK(helResume(thread.getHandle()));
-			}else if(error == Error::badExecutable) {
+			}else if(error == Error::badExecutable || error == Error::eof) {
 				gprs[kHelRegError] = kHelErrNone;
 				gprs[kHelRegOut0] = ENOEXEC;
 				HEL_CHECK(helStoreRegisters(thread.getHandle(), kHelRegsGeneral, &gprs));
 
 				HEL_CHECK(helResume(thread.getHandle()));
-			}else
-				assert(error == Error::success);
+			}else {
+				// Unhandled error, log and bubble up EIO
+				std::cout << "posix: exec: unhandled error from Process::exec, we got: " << (int)error << std::endl;
+				gprs[kHelRegError] = kHelErrNone;
+				gprs[kHelRegOut0] = EIO;
+				HEL_CHECK(helStoreRegisters(thread.getHandle(), kHelRegsGeneral, &gprs));
+
+				HEL_CHECK(helResume(thread.getHandle()));
+			}
 		}else if(observe.observation() == kHelObserveSuperCall + posix::superExit) {
 			if(logRequests)
 				std::cout << "posix: EXIT supercall" << std::endl;

diff --git a/posix/subsystem/src/util.cpp b/posix/subsystem/src/util.cpp
@@ -25,6 +25,7 @@ std::ostream& operator<<(std::ostream& os, const Error& err) {
 		case Error::isDirectory: err_string = "isDirectory"; break;
 		case Error::noMemory: err_string = "noMemory"; break;
 		case Error::directoryNotEmpty: err_string = "directoryNotEmpty"; break;
+		case Error::ioError: err_string = "ioError"; break;
 	}
 
 	return os << err_string;