Avoid closing stdin/stdout/stderr standard streams

include/asm/main.hpp

@@ -9,6 +9,7 @@
 #include <string>
 
 #include "helpers.hpp" // assume
+#include "util.hpp"    // xfclose
 
 enum MissingInclude {
 	INC_ERROR,    // A missing included file is an error that halts assembly
@@ -32,7 +33,7 @@ struct Options {
 
 	~Options() {
 		if (dependFile) {
-			fclose(dependFile);
+			xfclose(dependFile);
 		}
 	}
 

include/util.hpp

@@ -8,6 +8,7 @@
 #include <optional>
 #include <stddef.h>
 #include <stdint.h>
+#include <stdio.h>
 #include <string_view>
 #include <unordered_map>
 
@@ -21,6 +22,10 @@ enum NumberBase {
 	BASE_16 = 16,
 };
 
+// File-closing functions that will not close standard streams
+int xfclose(FILE *file);
+int xclose(int fd);
+
 // Locale-independent character class functions
 bool isNewline(int c);
 bool isBlankSpace(int c);

src/asm/actions.cpp

@@ -18,6 +18,7 @@
 #include "extern/utf8decoder.hpp"
 #include "helpers.hpp"
 #include "linkdefs.hpp"
+#include "util.hpp" // xfclose
 
 #include "asm/charmap.hpp"
 #include "asm/format.hpp"
@@ -147,7 +148,7 @@ std::optional<std::string> act_ReadFile(std::string const &name, uint32_t maxLen
 		}
 		return "";
 	}
-	Defer closeFile{[&] { fclose(file); }};
+	Defer closeFile{[&] { xfclose(file); }};
 
 	size_t readSize = maxLen;
 	if (fseek(file, 0, SEEK_END) == 0) {

src/asm/lexer.cpp

@@ -405,11 +405,7 @@ void LexerState::setFileAsNextState(std::string const &filePath, bool updateStat
 
 	if (fd >= 0) {
 		// If the file is stdin, or if measuring its size failed, read it in pieces
-		Defer closeFile{[&] {
-			if (fd != STDIN_FILENO) {
-				close(fd);
-			}
-		}};
+		Defer closeFile{[&] { xclose(fd); }};
 
 		// Reasonably large buffer size for `read` performance
 		char buf[8192];

src/asm/output.cpp

@@ -17,6 +17,7 @@
 #include "helpers.hpp" // assume, Defer
 #include "linkdefs.hpp"
 #include "platform.hpp"
+#include "util.hpp" // xfclose
 
 #include "asm/charmap.hpp"
 #include "asm/fstack.hpp"
@@ -210,7 +211,7 @@ void out_WriteObject() {
 		fatal("Failed to open object file \"%s\": %s", objectFileName, strerror(errno));
 		// LCOV_EXCL_STOP
 	}
-	Defer closeFile{[&] { fclose(file); }};
+	Defer closeFile{[&] { xfclose(file); }};
 
 	// Also write symbols that weren't written above
 	sym_ForEach(out_RegisterSymbol);
@@ -389,7 +390,7 @@ void out_WriteState(std::string name, std::vector<StateFeature> const &features)
 		fatal("Failed to open state file \"%s\": %s", name.c_str(), strerror(errno));
 		// LCOV_EXCL_STOP
 	}
-	Defer closeFile{[&] { fclose(file); }};
+	Defer closeFile{[&] { xfclose(file); }};
 
 	static char const *dumpHeadings[NB_STATE_FEATURES] = {
 	    "Numeric constants",

src/asm/section.cpp

@@ -21,6 +21,7 @@
 #include "helpers.hpp"
 #include "itertools.hpp" // InsertionOrderedMap
 #include "linkdefs.hpp"
+#include "util.hpp" // xfclose
 
 #include "asm/fstack.hpp"
 #include "asm/lexer.hpp"
@@ -974,7 +975,7 @@ bool sect_BinaryFile(std::string const &name, uint32_t startPos) {
 	if (!file) {
 		return fstk_FileError(name, "`INCBIN`");
 	}
-	Defer closeFile{[&] { fclose(file); }};
+	Defer closeFile{[&] { xfclose(file); }};
 
 	if (fseek(file, 0, SEEK_END) == 0) {
 		if (unsigned long fsize = ftell(file);
@@ -1035,7 +1036,7 @@ bool sect_BinaryFileSlice(std::string const &name, uint32_t startPos, uint32_t l
 	if (!file) {
 		return fstk_FileError(name, "`INCBIN`");
 	}
-	Defer closeFile{[&] { fclose(file); }};
+	Defer closeFile{[&] { xfclose(file); }};
 
 	if (fseek(file, 0, SEEK_END) == 0) {
 		if (unsigned long fsize = ftell(file);

src/fix/fix.cpp

@@ -15,6 +15,7 @@
 #include "diagnostics.hpp"
 #include "helpers.hpp"
 #include "platform.hpp"
+#include "util.hpp" // xclose, xfclose
 
 #include "fix/main.hpp"
 #include "fix/mbc.hpp"
@@ -463,7 +464,6 @@ bool fix_ProcessFile(char const *name, char const *outputName) {
 	}
 
 	int output = -1;
-	bool openedOutput = false;
 	if (outputName) {
 		if (!strcmp(outputName, "-")) {
 			output = STDOUT_FILENO;
@@ -476,12 +476,11 @@ bool fix_ProcessFile(char const *name, char const *outputName) {
 				return true;
 				// LCOV_EXCL_STOP
 			}
-			openedOutput = true;
 		}
 	}
 	Defer closeOutput{[&] {
-		if (openedOutput) {
-			close(output);
+		if (outputName) {
+			xclose(output);
 		}
 	}};
 
@@ -497,7 +496,7 @@ bool fix_ProcessFile(char const *name, char const *outputName) {
 		// operations may fail, all of which we handle.
 		error("Failed to open \"%s\" for reading+writing: %s", name, strerror(errno));
 	} else {
-		Defer closeInput{[&] { close(input); }};
+		Defer closeInput{[&] { xclose(input); }};
 		struct stat stat;
 		if (fstat(input, &stat) == -1) {
 			error("Failed to stat \"%s\": %s", name, strerror(errno)); // LCOV_EXCL_LINE

src/fix/main.cpp

@@ -308,7 +308,7 @@ static void initLogo() {
 			fatal("Failed to open \"%s\" for reading: %s", logoFilename, strerror(errno));
 			// LCOV_EXCL_STOP
 		}
-		Defer closeLogo{[&] { fclose(logoFile); }};
+		Defer closeLogo{[&] { xfclose(logoFile); }};
 
 		uint8_t logoBpp[sizeof(options.logo)];
 		if (size_t nbRead = fread(logoBpp, 1, sizeof(logoBpp), logoFile);

src/link/object.cpp

@@ -19,6 +19,7 @@
 #include "helpers.hpp"
 #include "linkdefs.hpp"
 #include "platform.hpp"
+#include "util.hpp" // xfclose
 #include "verbosity.hpp"
 #include "version.hpp"
 
@@ -446,7 +447,7 @@ void obj_ReadFile(std::string const &filePath, size_t fileID) {
 	if (!file) {
 		fatal("Failed to open file \"%s\": %s", fileName, strerror(errno));
 	}
-	Defer closeFile{[&] { fclose(file); }};
+	Defer closeFile{[&] { xfclose(file); }};
 
 	// First, check if the object is a RGBDS object, a SDCC one, or neither.
 	// A single `ungetc` is guaranteed to work.

src/link/output.cpp

@@ -218,7 +218,7 @@ static void writeROM() {
 	}
 	Defer closeOutputFile{[&] {
 		if (outputFile) {
-			fclose(outputFile);
+			xfclose(outputFile);
 		}
 	}};
 
@@ -237,7 +237,7 @@ static void writeROM() {
 	}
 	Defer closeOverlayFile{[&] {
 		if (overlayFile) {
-			fclose(overlayFile);
+			xfclose(overlayFile);
 		}
 	}};
 
@@ -556,7 +556,7 @@ static void writeSym() {
 	if (!symFile) {
 		fatal("Failed to open sym file \"%s\": %s", symFileName, strerror(errno));
 	}
-	Defer closeSymFile{[&] { fclose(symFile); }};
+	Defer closeSymFile{[&] { xfclose(symFile); }};
 
 	fputs("; File generated by rgblink\n", symFile);
 
@@ -607,7 +607,7 @@ static void writeMap() {
 	if (!mapFile) {
 		fatal("Failed to open map file \"%s\": %s", mapFileName, strerror(errno));
 	}
-	Defer closeMapFile{[&] { fclose(mapFile); }};
+	Defer closeMapFile{[&] { xfclose(mapFile); }};
 
 	writeMapSummary();
 

src/util.cpp

@@ -9,6 +9,21 @@
 #include <string.h> // strspn
 
 #include "helpers.hpp" // assume
+#include "platform.hpp"
+
+int xfclose(FILE *file) {
+	if (file == stdin || file == stdout || file == stderr) {
+		return 0;
+	}
+	return fclose(file);
+}
+
+int xclose(int fd) {
+	if (fd == STDIN_FILENO || fd == STDOUT_FILENO || fd == STDERR_FILENO) {
+		return 0;
+	}
+	return close(fd);
+}
 
 bool isNewline(int c) {
 	return c == '\r' || c == '\n';