1 files changed, 49 insertions, 0 deletions
diff --git a/test/x32_mmap.c b/test/x32_mmap.c
new file mode 100644
index 0000000..cbef36d
--- /dev/null
+++ b/test/x32_mmap.c
@@ -0,0 +1,49 @@
+// Test program which explores whether mmap's ofs parameter
+// is 64-bit, and whether it needs to be shifted << PAGE_SHIFT.
+// Apparently it is 64-bit and isn't shifted.
+//
+// Build: x86_64-gcc -static -Wall -ox32_mmap x32_mmap.c
+// Typical output:
+// 7f9390696000-7f93906a6000 r--s 12345670000 08:06 2224545 /etc/passwd
+//                                ^^^^^^^^^^^
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+// Ensure we are compiling to 64 bits
+struct bug { int t[sizeof(long) > 4 ? 1 : -1]; };
+int main(int argc, char **argv)
+{
+	long ofs = 0x12345670000; // fails if not page-aligned
+	errno = 0;
+	close(0);
+	if (open("/etc/passwd", O_RDONLY))
+		return 1;
+	long r = syscall(
+		(long) (__NR_mmap | 0x40000000), // make x32 call
+		(long) (0),		// start
+		(long) (0x10000),	// len
+		(long) (PROT_READ),	// prot
+		(long) (MAP_SHARED),	// flags
+		(long) (0),		// fd
+		(long) (ofs)		// ofs
+	);
+	printf("ret:0x%lx errno:%m\n", r);
+
+	char buf[16*1024];
+	sprintf(buf, "/proc/%d/maps", getpid());
+	int fd = open(buf, O_RDONLY);
+	if (fd > 0) {
+		int sz = read(fd, buf, sizeof(buf));
+		if (sz > 0)
+			write(1, buf, sz);
+	}
+
+	return 0;
+}