diff --git a/lib/std/os/linux.zig b/lib/std/os/linux.zig index eb2f71cf99..9550518842 100644 --- a/lib/std/os/linux.zig +++ b/lib/std/os/linux.zig @@ -193,9 +193,29 @@ pub fn umount2(special: [*]const u8, flags: u32) usize { pub fn mmap(address: ?[*]u8, length: usize, prot: usize, flags: u32, fd: i32, offset: u64) usize { if (@hasDecl(@This(), "SYS_mmap2")) { - return syscall6(SYS_mmap2, @ptrToInt(address), length, prot, flags, @bitCast(usize, isize(fd)), @truncate(usize, offset / MMAP2_UNIT)); + // Make sure the offset is also specified in multiples of page size + if ((offset & (MMAP2_UNIT - 1)) != 0) + return @bitCast(usize, isize(-EINVAL)); + + return syscall6( + SYS_mmap2, + @ptrToInt(address), + length, + prot, + flags, + @bitCast(usize, isize(fd)), + @truncate(usize, offset / MMAP2_UNIT), + ); } else { - return syscall6(SYS_mmap, @ptrToInt(address), length, prot, flags, @bitCast(usize, isize(fd)), offset); + return syscall6( + SYS_mmap, + @ptrToInt(address), + length, + prot, + flags, + @bitCast(usize, isize(fd)), + offset, + ); } }