It looks like they're considered a bad idea, so let's not add
them before we need them. I figured it's good to have them in
git history if we ever do need them though, hence the add/remove
dance.
Add seteuid()/setegid() under _POSIX_SAVED_IDS semantics,
which also requires adding suid and sgid to Process, and
changing setuid()/setgid() to honor these semantics.
The exact semantics aren't specified by POSIX and differ
between different Unix implementations. This patch makes
serenity follow FreeBSD. The 2002 USENIX paper
"Setuid Demystified" explains the differences well.
In addition to seteuid() and setegid() this also adds
setreuid()/setregid() and setresuid()/setresgid(), and
the accessors getresuid()/getresgid().
Also reorder uid/euid functions so that they are the
same order everywhere (namely, the order that
geteuid()/getuid() already have).
Previously 4 bytes at once were read and compared to the string
"DATA". This worked when the DATA marker was aligned on a 32-bit
boundary relative to the start of the file. However, this is not
guranteed to always be the case, and for some files the loader
would just keep searching for the marker.
The stacking context tree doesn't affect layout at all, so let's move
it into the Painting/ directory. I'm not sure yet if it's worth going
for a fullly separate painting tree. So far I'm thinking a stacking
context tree with pointers into the layout tree might be enough.
"Paint" matches what we call this in the rest of the system. Let's not
confuse things by mixing paint/render/draw all the time. I'm guilty of
this in more places..
Also rename RenderingContext => PaintContext.
The shrink-to-fit width algorithm actually works a little bit different
in the absolute positioning context, so it can't share all of its code
with non-absolute positioning.
Also, inline-block elements were always inserting unnecessary line
breaks when splitting, which caused the preferred width to be smaller
than it should be. This patch fixes that as well, by just not breaking
after inline-block elements in LayoutMode::OnlyRequiredLineBreaks.
CSS defines a very specific paint order. This patch starts steering us
towards respecting that by introducing the PaintPhase enum with values:
- Background
- Border
- Foreground
- Overlay (internal overlays used by inspector)
Basically, to get the right visual result, we have to render the page
multiple times, going one phase at a time.
All the file actions stuff is still missing for now,
as is POSIX_SPAWN_SETSCHEDULER (not sure what that's
supposed to do) and POSIX_SPAWN_RESETIDS.
Implemented in userspace for now. Once there are users,
it'll likely make sense to make this a syscall for
performance reasons.
A simple test program of the form
extern char **environ;
int main(int argc, char* argv[])
{
pid_t pid;
char* args[] = { "ls", NULL };
posix_spawnp(&pid, "ls", nullptr, nullptr, args, environ);
}
works fine.
We were getting a little overly memey in some places, so let's scale
things back to business-casual.
Informal language is fine in comments, commits and debug logs,
but let's keep the runtime nice and presentable. :^)
This is a convenient wrapper around readlink() that hides away the details
of buffers and buffer sizes, and simply returns a String. The best part is it
doesn't rely on PATH_MAX :D
It comes in two versions, for Serenity, where we can pass non-null-terminated
strings to syscalls, and where sys$readlink() returns the total link size, and
for other systems, where we have to copy out the string, and always have to do
two syscalls.
That's not how readlink() is supposed to work: it should copy as many bytes
as fit into the buffer, and return the number of bytes copied. So do that,
but add a twist: make sys$readlink() actually return the whole size, not
the number of bytes copied. We fix up this return value in userspace, to make
LibC's readlink() behave as expected, but this will also allow other code
to allocate a buffer of just the right size.
Also, avoid an extra copy of the link target.
The more generic virtual variant is renamed to node_name() and now only
Element has tag_name(). This removes a huge amount of String ctor/dtor
churn in selector matching.
Hey, why not. We did all the hard work for display:inline-block already
and now we can just allow this.
This makes <a><h1>Hello friends!</h1></a> work :^)
To support z-ordering when painting, the layout tree now has a parallel
sparse tree of stacking contexts. The rules for which layout boxes
establish a stacking context are a bit complex, but the intent is to
encapsulate the decision making into establishes_stacking_context().
When we paint, we start from the ICB (LayoutDocument) who always has a
StackingContext and then paint the tree of StackingContexts where each
node has its children sorted by z-index.
This is pretty crude, but gets the basic job done. Note that this does
not yet support hit testing; hit testing is still done using a naive
treewalk from the root.
The only layout nodes that don't have their own style are LayoutText
(they inherit the style from their parent element since text cannot
be styled by CSS.)
However, it never makes sense for text nodes to have absolute position
so don't claim it.
