According to the Single UNIX Specification, Version 2 that's where
those macros should be defined. This fixes the libiconv port.
This also fixes some (but not all) build errors for the diffutils and nano ports.
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
This achieves two things:
- Programs can now intentionally perform arbitrary syscalls by calling
syscall(). This allows us to work on things like syscall fuzzing.
- It restricts the ability of userspace to make syscalls to a single
4KB page of code. In order to call the kernel directly, an attacker
must now locate this page and call through it.
Just ignore all these environment flags if the AT_SECURE flag is set in
the program's auxiliary vector.
This prevents a user from tricking set-uid programs into dumping debug
information via environment flags.
This allows us to implement mkstemp() with open() directly, instead of
first lstat()'ing, and then open()'ing the filename.
Also implement tmpfile() in terms of mkstemp() instead of mktemp().
The realpath syscall can attempt to return arbitrarily long paths, in particular
paths that are longer than PATH_MAX. The only way to detect this case is
checking whether 'rc', the true length of the returned path including NUL byte,
exceeds our buffer length. In such a case, the buffer contains invalid data.
All Serenity code calls LibC's realpath() with a nullptr buffer, meaning that
realpath is supposed to allocate memory on its own. All Serenity code can handle
arbitrarily long paths returned by LibC's realpath, so it is safe to "do the
dance" and repeat the syscall with a new buffer.
Ports are likely to be graceful in this regard, too. If a Port calls realpath()
with a pre-allocated buffer, however, there is nothing better we can do than
return a truncated buffer.
