clean up code and make it easy to extend

test/mmap/mmap.c

@@ -5,23 +5,69 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include <errno.h>
 #include <unistd.h>
 #include <sys/mman.h>
 
+#define SIZEOF_ARRAY(type) (sizeof(type)/sizeof(*type))
+
+struct mmap_test {
+	void *ret;
+	int err;
+	struct {
+		void *start;
+		size_t length;
+		int prot;
+		int flags;
+		int fd;
+		off_t offset;
+	} args;
+};
+
+struct mmap_test tests[] = {
+	[0] {
+		.err = 0,
+		.args.start = NULL,
+		.args.length = 4096,
+		.args.prot = PROT_READ|PROT_WRITE,
+		.args.flags = MAP_PRIVATE|MAP_ANONYMOUS,
+		.args.fd = 0,
+		.args.offset = 0
+	},
+};
+
+#define err(fmt, args...) \
+	do { \
+		fprintf(stderr, fmt "\n" , ## args); \
+		exit(1); \
+	} while (0)
+#define errp(fmt, args...) err(fmt ": %s" , ## args , strerror(errno))
 
 int main(int argc, char **argv)
 {
-	void *ptr;
+	int i;
+	struct mmap_test *t;
 
+	for (i=0; i<SIZEOF_ARRAY(tests); ++i) {
+		t = tests + i;
 
-	ptr = mmap(NULL, 4096, PROT_READ|PROT_WRITE,
-		MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+		errno = 0;
+		t->ret = mmap(t->args.start, t->args.length, t->args.prot,
+		              t->args.flags, t->args.fd, t->args.offset);
 
-	if(ptr==MAP_FAILED){
-		perror("mmap");
-		exit(1);
+		if (t->err) {
+			if (t->ret != MAP_FAILED)
+				err("mmap test %i should have failed, but gave us %p", i, t->ret);
+			else if (t->err != errno)
+				errp("mmap test %i failed, but gave us wrong errno (got %i instead of %i)", i, errno, t->err);
+		} else {
+			if (t->ret == MAP_FAILED)
+				errp("mmap test %i failed", i);
+			else if (munmap(t->ret, t->args.length) != 0)
+				errp("munmap test %i failed", i);
+		}
 	}
-	printf("mmap returned %p\n",ptr);
+
 	exit(0);
 }
-