Previously, we assumed that the `.text` segment was loaded at vaddr 0 in
shared object, which is not the case with `-z separate-code` enabled.
Because we didn't do the right calculations to translate an address from
a performance event into its value within the ELF file, Profiler would
try to disassemble out-of-bounds memory locations, leading to a crash.
This commit also changes `LibraryMetadata` to apply to a loaded library
as a whole, not just to one of its segments (like .text or .data). This
lets us simplify the interface, as we no longer have to worry about
`text_base`.
Fixes#10628
Since our executables are position-independent, the address values
extraced from processes don't correspond to their values within the ELF
file. We have to offset the absolute addresses by the load base address
to get the relative symbol that we need for disassembly.
Now that the kernel is compiled as a PIE, all addresses are relative to
the loaded base address, so Symbolication::kernel_base has to be
subtracted off from the absolute addresses if we want to symbolicate
them.
Also add a test to prevent this from happening again. There were two
bugs:
* The number of bytes just after processing the last value was written,
instead of the number of bytes after skipping remaining whitespace.
Confirmed by testing against GNU's `scanf()` since the man page
leaves something to be desired.
* The number of bytes was written to the wrong variable argument; i.e.
the first argument was overwritten.
Used these commands to test it:
printf 'HTTP/1.0 200 OK\r\n%s\r\n\r\n%s' 'Content-Length: 4' \
'well hello friends!' | nc -lN 0.0.0.0 8000
pro http://0.0.0.0:8000
(Actually, this also needs a Content-Encoding header, as response
streaming is disabled then. It didn't fit in the title.)
We were creating too small buffer -- instead of assigning the total
received buffer size, we were using the Content-Length value.
As you can see, the m_buffered_size might now exceed the Content-Length
value, but that will be handled in next commits, regardless if
the response can be streamed or not. :^)
Here's a minimal code that caused crash before:
printf 'HTTP/1.0 200 OK\r\n%s\r\n%s\r\n\r\n%s' \
'Content-Encoding: anything' 'Content-Length: 3' \
':^)AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA' | nc -lN 0.0.0.0 8000
pro http://0.0.0.0:8000
Previously we assumed there were less kernel samples than user samples,
by implicitly using the kernel histogram size for indicies to the user
histogram. Such a profile can be reproduced by profiling a very short
lived program like true: `profile -c true`
Beforehand we were dividing the frame width by the profile length in ms
and then dividing the frame width by the result once more, which is
equivalent to (but slower) just using the length in ms directly, aside
from the case in which the profile is less than 1 ms long, in which
case this would trigger undefined behaviour due to the division by zero
This function implements CSS color syntax, which is case-insensitive in
HTML contexts. Making it insensitive here means not having to remember
to do it in every user, (many of the HTML elements do not do this,) and
means they don't have to produce a lowercase copy of the input string
before passing it.
If a mouse button was clicked, `EventLoop::drain_mouse()` would always
send the last MousePacket state to the screen input - even if that
state is equivalent to the last state sent as part of the button logic.
By remembering if the state was already sent, we prevent sending that
state a second time saving some resources in the process.
Bit 3 is set here:
c5b2f55981/hw/input/ps2.c (L736)
Spurious mouse packets can be received without this bit set, for
example when double-clicking and keeping the mouse button depressed
instead of releasing it the second time (i.e. mousedown > mouseup >
mousedown). We should not process such packets.
This makes interaction with our buttons much smoother!
Fixes#5881.
Instead of detecting which flag was set in the status register, we can
use the instrument type passed to us. This works because the mouse and
keyboard use different IRQs.
This issue was also present in the kernel, the description of which is
provided in an identically titled commit.
Note that this couldn't have affected any programs running in
UserspaceEmulator as we don't support SSE instructions, and don't seem
to raise faults under any conditions.
The System V ABI requires that the stack is 16-byte aligned on function
call. Confusingly, however, they mean that the stack must be aligned
this way **before** the `CALL` instruction is executed. That instruction
pushes the return value onto the stack, so the callee will actually see
the stack pointer as a value `sizeof(FlatPtr)` smaller.
The signal trampoline was written with this in mind, but `setup_stack`
aligned the entire stack, *including the return address* to a 16-byte
boundary. Because of this, the trampoline subtracted too much from the
stack pointer, thus misaligning it.
This was not a problem on i686 because we didn't execute any
instructions from signal handlers that would require memory operands to
be aligned to more than 4 bytes. This is not the case, however, on
x86_64, where SSE instructions are enabled by default and they require
16-byte aligned operands. Running such instructions raised a GP fault,
immediately killing the offending program with a SIGSEGV signal.
This issue caused TestKernelAlarm to fail in LibC when ran locally, and
at one point, the zsh port was affected too.
Fixes#9291
If the Value is a non-negative Int32, create a numeric PropertyKey
instead of making a string key.
This makes "ai-astar" test from the Kraken benchmark run in 30 seconds,
down from 42 seconds. :^)
Instead of returning JS::StringOrSymbol, which is a space-optimized type
used in Shape property tables, this now returns JS::PropertyKey which is
*not* space-optimized, but has other niceties like optimized storage of
numeric ("indexed") properties.
This is a specialized string table for storing identifiers only.
Identifiers are always FlyStrings, which makes many common operations
faster by allowing O(1) comparison.
They were previously taking up 9% of samples in a profile of PixelPaint
while selecting a mask, and as a result of moving them to the header
they were inlined, which effectively eliminated them from the profile.
Commit cf0dbc906 recently added the ability for setuid binaries to be
located in /usr/Tests. This should really now be read only to mitigate
the potential misuse of any of the setuid binaries.
By replacing this VERIFY with a thrown Error we no longer crash when
calling a generator function in the AST interpreter. This allows us to
more gracefully handle situation which have not been implemented yet.
In particular this helps the libjs-test262-runner since it can now
continue on to the next tests instead of having the entire process end.
We always use UTF-8, meaning that a single `wchar_t` might be converted
into up to 4 `char`s. This would cause a buffer overflow if something
actually relied on this being the right value.
The C standard states that these symbols should be declared as macros,
not as emum variants as we were doing previously. This is used in some
ports (e.g. bash) to conditionally compile locale-dependent
functionality.
We now use the same trick here as with the errno constants. We keep the
enum, but also create macros that defer to the enum variants.
The main event loop pushes itself onto the event loop stack, and so it
should also pop itself when destroyed.
This will surface attempts to use the event loop stack after the main
event loop has been destroyed.
