shithub: rgbds

Info  •  Files  •  Log  •  Branches

Prevent RGBASM from outputting corrupted files

Properly fixes #451

--- a/src/asm/output.c

+++ b/src/asm/output.c

@@ -408,13 +408,12 @@

  */

 void out_WriteObject(void)

 {

-	FILE *f;

 	struct Section *pSect;

 	struct Assertion *assert = assertions;

+	FILE *f = tmpfile(); /* Avoids producing a corrupted file on error */

-	f = fopen(tzObjectname, "wb");

 	if (!f)

-		err(1, "Couldn't write file '%s'", tzObjectname);

+		err(1, "Couldn't create temporary file");

 	/* Also write exported symbols that weren't written above */

 	sym_ForEach(registerExportedSymbol, NULL);

@@ -441,6 +440,31 @@

 		assert = assert->next;

 	}

+	/* We're finished writing the file; now, copy it to the final one */

+	FILE *objFile = fopen(tzObjectname, "wb");

+	long size = ftell(f);

+	char buf[1024];

+

+	rewind(f);

+	while (size) {

+		long blockSize = size < sizeof(buf) ? size : sizeof(buf);

+

+		if (fread(buf, blockSize, 1, f) < 1

+		 || fwrite(buf, blockSize, 1, objFile) < 1) {

+			char const *errmsg =

+				ferror(f) || ferror(objFile) ? strerror(errno)

+							     : "end of file";

+

+			fclose(objFile);

+			fclose(f);

+			remove(tzObjectname);

+			errx(1, "Failed to write file \"%s\": %s", tzObjectname,

+			     errmsg);

+		}

+		size -= blockSize;

+	}

+

+	fclose(objFile);

 	fclose(f);

 }