After commit 91a03bc6ae we no longer try
to discover files for exec-ing by simply trying to exec on them, but we
check for the files existence by using `Core::file::exists()` first.
Contrary to the old solution, this now requires the `rpath` pledge, so
pledge it to keep `strace` from crashing when using non-absolute paths.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
Error::from_string_literal now takes direct char const*s, while
Error::from_string_view does what Error::from_string_literal used to do:
taking StringViews. This change will remove the need to insert `sv`
after error strings when returning string literal errors once
StringView(char const*) is removed.
No functional changes.
This commit moves the length calculations out to be directly on the
StringView users. This is an important step towards the goal of removing
StringView(char const*), as it moves the responsibility of calculating
the size of the string to the user of the StringView (which will prevent
naive uses causing OOB access).
Apologies for the enormous commit, but I don't see a way to split this
up nicely. In the vast majority of cases it's a simple change. A few
extra places can use TRY instead of manual error checking though. :^)
The actual length of the resulting string is encoded in the return
value; treating the entire buffer as a string leads to reading
uninitialized memory.
This feature was introduced in version 4.17 of the Linux kernel, and
while it's not specified by POSIX, I think it will be a nice addition to
our system.
MAP_FIXED_NOREPLACE provides a less error-prone alternative to
MAP_FIXED: while regular fixed mappings would cause any intersecting
ranges to be unmapped, MAP_FIXED_NOREPLACE returns EEXIST instead. This
ensures that we don't corrupt our process's address space if something
is already at the requested address.
Note that the more portable way to do this is to use regular
MAP_ANONYMOUS, and check afterwards whether the returned address matches
what we wanted. This, however, has a large performance impact on
programs like Wine which try to reserve large portions of the address
space at once, as the non-matching addresses have to be unmapped
separately.
In particular, strace can now stomach memory errors while copying
invalid strings.
Example with a valid string:
dbgputstr("95.976 traceme(38:38) Well, Hello Friends!") = 55
Example with an invalid string:
dbgputstr(Error(errno=14){0x00012345, 678b}) = -14 EFAULT
(ANSI escapes removed for readability.)
This necessarily introduces some usages (and benefits!) of the new
ErrorOr<> pattern. To keep commits atomic, I do not yet rewrite the
entire program to use ErrorOr<> correctly.
This isn't a complete conversion to ErrorOr<void>, but a good chunk.
The end goal here is to propagate buffer allocation failures to the
caller, and allow the use of TRY() with formatting functions.
We create a base class called GenericFramebufferDevice, which defines
all the virtual functions that must be implemented by a
FramebufferDevice. Then, we make the VirtIO FramebufferDevice and other
FramebufferDevice implementations inherit from it.
The most important consequence of rearranging the classes is that we now
have one IOCTL method, so all drivers should be committed to not
override the IOCTL method or make their own IOCTLs of FramebufferDevice.
All graphical IOCTLs are known to all FramebufferDevices, and it's up to
the specific implementation whether to support them or discard them (so
we require extensive usage of KResult and KResultOr, together with
virtual characteristic functions).
As a result, the interface is much cleaner and understandable to read.
By default strace outputs all system calls the monitored process
invokes, but it's sometimes useful to either exclude some calls, or to
include only some others.
This commit adds two new command line options to specify two
exclusion/inclusion command-delimited lists of system calls. These are
then used to decide if an intercepted system call should be displayed in
the output or not.
This commit introduces the main infrastructure used for turning register
values into user-facing values that can be printed by strace. This
includes the ability to copy data from a particular memory address in
the traced process. On top of this, (partial) formatting has been added
for the most common I/O operations (open, read, write, lseek, close,
stat, fstat).
Moving the formatting of strace's output into a separate function will
allow us to introduce more complexity into the formatting logic without
touching the main body of the program.
The new function uses a switch statement to select how to format the
arguments and result depending on the syscall. At this point we only
include the default formatting, where the registers are simply dumped,
but later on we can add specializations for each system call we want to
support.
