This changes the signatures for FILE::seek and FILE::tell, to use
`off_t` as they use lseek internally. `fpos_t` is also redefined to use
`off_t`.
Dr. POSIX says that fpos_t is:
> A non-array type containing all information needed to specify uniquely
> every position within a file.
In practice, most *NIX typedef it to `off_t`, or a struct containing an
`off_t` and some internal state.
This was a goofy kernel API where you could assign an icon_id (int) to
a process which referred to a global shbuf with a 16x16 icon bitmap
inside it.
Instead of this, programs that want to display a process icon now
retrieve it from the process executable instead.
Problem:
- C functions with no arguments require a single `void` in the argument list.
Solution:
- Put the `void` in the argument list of functions in C header files.
This new flag controls two things:
- Whether the kernel will generate core dumps for the process
- Whether the EUID:EGID should own the process's files in /proc
Processes are automatically made non-dumpable when their EUID or EGID is
changed, either via syscalls that specifically modify those ID's, or via
sys$execve(), when a set-uid or set-gid program is executed.
A process can change its own dumpable flag at any time by calling the
new sys$prctl(PR_SET_DUMPABLE) syscall.
Fixes#4504.
POSIX says we can set errno EINVAL and return -1 if the action is not
supported. This is better than crashing, and fixes bash crashing
whenever you press ^C.
We now configure the gcc spec files to use a different crt files for
static & PIE binaries.
This relieves us from the need to explicitly specify the desired crt0
file in cmake scripts.
LibC stdlib `arc4random()` uses the `getrandom` system call which
uses `KernelRng::get_good_random_bytes`.
This ensures that filenames generated using functions such as
`mkstemp()` are suitably randomised and are no longer predictable.
This implements a number of changes related to time:
* If a HPET is present, it is now used only as a system timer, unless
the Local APIC timer is used (in which case the HPET timer will not
trigger any interrupts at all).
* If a HPET is present, the current time can now be as accurate as the
chip can be, independently from the system timer. We now query the
HPET main counter for the current time in CPU #0's system timer
interrupt, and use that as a base line. If a high precision time is
queried, that base line is used in combination with quering the HPET
timer directly, which should give a much more accurate time stamp at
the expense of more overhead. For faster time stamps, the more coarse
value based on the last interrupt will be returned. This also means
that any missed interrupts should not cause the time to drift.
* The default system interrupt rate is reduced to about 250 per second.
* Fix calculation of Thread CPU usage by using the amount of ticks they
used rather than the number of times a context switch happened.
* Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it
for most cases where precise timestamps are not needed.
Problem:
- `(void)` simply casts the expression to void. This is understood to
indicate that it is ignored, but this is really a compiler trick to
get the compiler to not generate a warning.
Solution:
- Use the `[[maybe_unused]]` attribute to indicate the value is unused.
Note:
- Functions taking a `(void)` argument list have also been changed to
`()` because this is not needed and shows up in the same grep
command.
The dynamic loader exists as /usr/lib/Loader.so and is loaded by the
kernel when ET_DYN programs are executed.
The dynamic loader is responsible for loading the dependencies of the
main program, allocating TLS storage, preparing all loaded objects for
execution and finally jumping to the entry of the main program.
This adds an allocate_tls syscall through which a userspace process
can request the allocation of a TLS region with a given size.
This will be used by the dynamic loader to allocate TLS for the main
executable & its libraries.
This makes the Scheduler a lot leaner by not having to evaluate
block conditions every time it is invoked. Instead evaluate them as
the states change, and unblock threads at that point.
This also implements some more waitid/waitpid/wait features and
behavior. For example, WUNTRACED and WNOWAIT are now supported. And
wait will now not return EINTR when SIGCHLD is delivered at the
same time.
This makes RegExpObject compile and store a Regex<ECMA262>, adds
all flag-related properties, and implements `RegExpPrototype.test()`
(complete with 'lastIndex' support) :^)
It should be noted that this only implements `test()' using the builtin
`exec()'.
This commit is a mix of several commits, squashed into one because the
commits before 'Move regex to own Library and fix all the broken stuff'
were not fixable in any elegant way.
The commits are listed below for "historical" purposes:
- AK: Add options/flags and Errors for regular expressions
Flags can be provided for any possible flavour by adding a new scoped enum.
Handling of flags is done by templated Options class and the overloaded
'|' and '&' operators.
- AK: Add Lexer for regular expressions
The lexer parses the input and extracts tokens needed to parse a regular
expression.
- AK: Add regex Parser and PosixExtendedParser
This patchset adds a abstract parser class that can be derived to implement
different parsers. A parser produces bytecode to be executed within the
regex matcher.
- AK: Add regex matcher
This patchset adds an regex matcher based on the principles of the T-REX VM.
The bytecode pruduced by the respective Parser is put into the matcher and
the VM will recursively execute the bytecode according to the available OpCodes.
Possible improvement: the recursion could be replaced by multi threading capabilities.
To match a Regular expression, e.g. for the Posix standard regular expression matcher
use the following API:
```
Pattern<PosixExtendedParser> pattern("^.*$");
auto result = pattern.match("Well, hello friends!\nHello World!"); // Match whole needle
EXPECT(result.count == 1);
EXPECT(result.matches.at(0).view.starts_with("Well"));
EXPECT(result.matches.at(0).view.end() == "!");
result = pattern.match("Well, hello friends!\nHello World!", PosixFlags::Multiline); // Match line by line
EXPECT(result.count == 2);
EXPECT(result.matches.at(0).view == "Well, hello friends!");
EXPECT(result.matches.at(1).view == "Hello World!");
EXPECT(pattern.has_match("Well,....")); // Just check if match without a result, which saves some resources.
```
- AK: Rework regex to work with opcodes objects
This patchsets reworks the matcher to work on a more structured base.
For that an abstract OpCode class and derived classes for the specific
OpCodes have been added. The respective opcode logic is contained in
each respective execute() method.
- AK: Add benchmark for regex
- AK: Some optimization in regex for runtime and memory
- LibRegex: Move regex to own Library and fix all the broken stuff
Now regex works again and grep utility is also in place for testing.
This commit also fixes the use of regex.h in C by making `regex_t`
an opaque (-ish) type, which makes its behaviour consistent between
C and C++ compilers.
Previously, <regex.h> would've blown C compilers up, and even if it
didn't, would've caused a leak in C code, and not in C++ code (due to
the existence of `OwnPtr` inside the struct).
To make this whole ordeal easier to deal with (for now), this pulls the
definitions of `reg*()` into LibRegex.
pros:
- The circular dependency between LibC and LibRegex is broken
- Eaiser to test (without accidentally pulling in the host's libc!)
cons:
- Using any of the regex.h functions will require the user to link -lregex
- The symbols will be missing from libc, which will be a big surprise
down the line (especially with shared libs).
Co-Authored-By: Ali Mohammad Pur <ali.mpfard@gmail.com>
The implementation uses atomics and futexes (yay!) and is heavily based on the
implementation I did for my learning project named "Let's write synchronization
primitives" [0].
That project, in fact, started when I tried to implement pthread_once() for
Serenity (because it was needed for another project of mine, stay tuned ;) ) and
was not very sure I got every case right. So now, after learning some more about
code patterns around atomics and futexes, I am reasonably sure, and it's time to
contribute the implementation of pthread_once() to Serenity :^)
[0] To be published at https://github.com/bugaevc/lets-write-sync-primitives
When we hit the last token, make the saved pointer point to the null
terminator instead of to the next token. This ensures that the next
call to strtok_r() returns null as expected.
Found by running GCC in UE. :^)
The pointers returned by malloc should always be 8-byte aligned on x86.
We were not consistent about this, as some ChunkedBlock size classes
were not divisible by 8.
This fixes some OOB reads found by running GCC in UE.
Most systems (Linux, OpenBSD) adjust 0.5 ms per second, or 0.5 us per
1 ms tick. That is, the clock is sped up or slowed down by at most
0.05%. This means adjusting the clock by 1 s takes 2000 s, and the
clock an be adjusted by at most 1.8 s per hour.
FreeBSD adjusts 5 ms per second if the remaining time adjustment is
>= 1 s (0.5%) , else it adjusts by 0.5 ms as well. This allows adjusting
by (almost) 18 s per hour.
Since Serenity OS can lose more than 22 s per hour (#3429), this
picks an adjustment rate up to 1% for now. This allows us to
adjust up to 36s per hour, which should be sufficient to adjust
the clock fast enough to keep up with how much time the clock
currently loses. Once we have a fancier NTP implementation that can
adjust tick rate in addition to offset, we can think about reducing
this.
adjtime is a bit old-school and most current POSIX-y OSs instead
implement adjtimex/ntp_adjtime, but a) we have to start somewhere
b) ntp_adjtime() is a fairly gnarly API. OpenBSD's adjfreq looks
like it might provide similar functionality with a nicer API. But
before worrying about all this, it's probably a good idea to get
to a place where the kernel APIs are (barely) good enough so that
we can write an ntp service, and once we have that we should write
a way to automatically evaluate how well it keeps the time adjusted,
and only then should we add improvements ot the adjustment mechanism.
When a mallocation is shrunk/grown without moving, UE needs to update
its precise metadata about the mallocation, since it tracks *exactly*
how many bytes were allocated, not just the malloc chunk size.
If you try to do this (e.g "mv directory directory"), sys$rename() will
now fail with EDIRINTOSELF.
Dr. POSIX says we should return EINVAL for this, but a custom error
code allows us to print a much more helpful error message when this
problem occurs. :^)
