Reduce the number of #ifdef blocks and use quint8 for the enums that
don't need more than 8 bits anyway (none of them do). Plus move the
std::function callback to an indirect block, as most users of QProcess
won't set them and this type is 4 pointers with libstdc++ and libc++.
After this, QProcessPrivate on 64-bit Unix is 688 bytes, of which:
- 392 bytes from QIODevicePrivate
- 295 bytes of own data
- 3x56 bytes per Channel (which have 5 bytes of tail padding each)
- 1 byte of tail padding and no middle padding
Pick-to: 6.5
Change-Id: Icfe44ecf285a480fafe4fffd174d188a0821d060
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
It was only used to later set exitStatus = CrashExit, so simply do it
early.
Drive-by removal of a magic numeric literal in the middle of the source
code. It's still magic, but at least we avoid accidentally making typos.
Pick-to: 6.5
Change-Id: Icfe44ecf285a480fafe4fffd174d4176a5d87641
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
ioctl call for FIONREAD takes an int arg, it won't work correctly
otherwise. Cast the return of the read() call to int, because it won't
read more than buffSize (which is an int).
Change-Id: I130202a732684257bbb0e79c9358b60a61010c46
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
I got tired of being told off by the inanity 'bot for faithfully
reflecting existing #if-ery in new #if-ery. Retain only the
documentation and definition of the deprecated define.
Change-Id: I47f47b76bd239a360f27ae5afe593dfad8746538
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
If the child failed to start, execChild() would (unnecessarily) store -1
in childStartedPipe[1] after writing the failure message to it and
closing that pipe. This had worked for the previous 20 years of QProcess
existence, because that was run in the child process. However, with 6.5
commit e1a787a76ed462e4ed49db78a40c6d7e272182d7 (cherry-picked to 6.4)
we implemented vfork-like behavior, meaning the child would share memory
with the parent and ran before the parent, so startProcess() failed to
close it:
// parent
// close the ends we don't use and make all pipes non-blocking
qt_safe_close(childStartedPipe[1]);
Also updated the docs to account for the fact that this is a vfork()
environment and, moreover, not using the vfork() function from glibc on
Linux.
[ChangeLog][QtCore][QProcess] Fixed a file descriptor leak in QProcess
when running on Linux 5.4 or later, if the executable being run failed
to start (for example, the file for the executable didn't exist).
Pick-to: 6.4.3 6.4 6.5
Task-number: QTBUG-111243
Change-Id: I7f354474adce419ca6c2fffd17481002e4853cc3
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
fork() works by implementing Copy-On-Write for all pages that either the
parent or the child process write to. So if the parent process continues
running while the child is between fork(2) and execve(2), then it will
keep causing page faults and requiring the OS to duplicate those pages,
which may be expensive (page table updates, TLB flushes, etc.). This
problem is aggravated if the parent process is multithreaded, as the
simple act of running in the parent will cause those threads' stacks to
cause page faults.
The BSD solution for that was vfork(), which has two differences in
behavior: (1) it blocks the parent from running and (2) it shares memory
with it. But it's always been tricky, so POSIX.1-2001 deprecated it and
2008 removed its definition completely. Still, it is available somewhat
widely, and on Linux that can be achieved with clone(2) and the
CLONE_VFORK and CLONE_VM flags, for those two behaviors respectively.
Because of (2), we can't return from the forkfd() function in the child
(as that would trash the stack in the parent process), so to implement
this functionality vforkfd() adds a callback of the same signature as
glibc's clone(2) wrapper (something that hadn't occurred to me when we
attempted to use CLONE_VFORK last time).
On Linux, (1) is no problem, as clone(2) has native forkfd support. But
on other OSes, forkfd() requires the parent to run before the child
execve()s, in order to save the child PID in the list of children we're
going to handle SIGCHLD for in a non-racy way. Investigating if it is
possible to use vfork() anyway is left as an exercise for the reader.
Matching OpenDCDiag pull request:
https://github.com/opendcdiag/opendcdiag/pull/94
Pick-to: 6.4
Fixes: QTBUG-104493
Change-Id: Id0fb9ab0089845ee8843fffd16fa63c7c6f7dd1c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
The forkfd_pidfd is a Linux feature, but we ended up disabling the
equivalent functionality on FreeBSD.
Pick-to: 6.3 6.4
Change-Id: I6d3880c7d99d4fc494c8fffd16fabfbc38865f94
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Replace the current license disclaimer in files by
a SPDX-License-Identifier.
Files that have to be modified by hand are modified.
License files are organized under LICENSES directory.
Task-number: QTBUG-67283
Change-Id: Id880c92784c40f3bbde861c0d93f58151c18b9f1
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
It expands to the first available of
- constinit (C++20)
- [[clang::require_constant_initialization]] (Clang)
- __constinit (GCC >= 10)
Use it around the code (on and near static QBasicAtomic; this patch
makes no attempt to find all statics in qtbase).
[ChangeLog][QtCore][QtGlobal] Added macro Q_CONSTINIT.
Fixes: QTBUG-100484
Change-Id: I11e0363a7acb3464476859d12ec7f94319d82be7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
As a drive-by, did also minor refactorings/improvements.
Task-number: QTBUG-98434
Change-Id: I81964176ae2f07ea63674c96f47f9c6aa046854f
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>
Unless "." (or the empty string) is in $PATH, we're not supposed to find
executables in the current directory. This is how the Unix shells behave
and we match their behavior. It's also the behavior Qt had prior to 5.9
(commit 28666d167aa8e602c0bea25ebc4d51b55005db13). On Windows, searching
the current directory is the norm, so we keep that behavior.
This commit does not add an explicit check for an empty return from
QStandardPaths::findExecutable(). Instead, we allow that empty string to
go all the way to execve(2), which will fail with ENOENT. We could catch
it early, before fork(2), but why add code for the error case?
See https://kde.org/info/security/advisory-20220131-1.txt
[ChangeLog][Important Behavior Changes] When passed a simple program
name with no slashes, QProcess on Unix systems will now only search the
current directory if "." is one of the entries in the PATH environment
variable. This bug fix restores the behavior QProcess had before Qt 5.9.
If launching an executable in the directory set by setWorkingDirectory()
or inherited from the parent is intended, pass a program name starting
with "./". For more information and best practices about finding an
executable, see QProcess' documentation.
Pick-to: 5.15 6.2 6.3
Change-Id: I54f205f6b7314351b078fffd16cf7013c97ee9fb
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
PIPE_BUF is optional in POSIX, e.g. "where the corresponding value is
equal to or greater than the stated minimum, but where the value can
vary depending on the file to which it is applied." [1]
GNU/Hurd does not provide PIPE_BUF, so fallback to its minimum
acceptable value, that is _POSIX_PIPE_BUF.
[1] https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html
Also, explicitly include <limits.h> in this file, to make sure PIPE_BUF
or _POSIX_PIPE_BUF are available without relying on other headers to
pull <limits.h>.
Change-Id: Ifae964db81841e1d31fc09e73b45594af9a326d1
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Several QIODevice subclasses use the qt_prettyDebug() function to get
a printable representation of the buffer data for debug output.
Rather than having this feature statically implemented in each
respective file, this patch introduces a generic function in the
QtDebugUtils namespace. Accordingly, some inaccuracies in the
use-cases have been corrected.
Change-Id: I1a8465cab08c8acf5fdcdba5085182511b1cbb7b
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
qprocess_unix.cpp:633:55: error: ‘i’ was not declared in this scope
Change-Id: I152fbd9df6e9d3f31e2c2c8b23a3c1ab87aa237a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Instead of having so much manual pointer manipulation and duplicated
code.
Change-Id: Ic90d8429a0eb4837971dfffd1664f8f63753440a
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
This harmonizes the execution between start() and startDetached(). Both
did QStandardDirs::findExecutable(), but duplicated code. However, only
start() supported launching .app bundles on Mac.
[ChangeLog][QtCore][QProcess] startDetached() now supports launching
.app executable bundles on macOS / iOS systems, like start() already
did.
Change-Id: Ic90d8429a0eb4837971dfffd1664f776b2c0edfd
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
We haven't used the spawn functionality on QNX since Qt 5.7 (commit
005a8bfbf0022f03dafafcf2b5c438ccf0675a49) because that's when we dropped
support for QNX 6.5.0.
Change-Id: Ic90d8429a0eb4837971dfffd1664f9712bdce2d8
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Use a structure that will automatically close them for us. This doesn't
apply to startProcess() because the pipes there are long-lived (though
each of them in QProcessPrivate could be an AutoPipe...).
The destructor only runs in the parent process, so the child processes
don't need to worry about setting file descriptors to -1.
Pick-to: 6.1
Change-Id: Ic90d8429a0eb4837971dfffd1664ed98f3d74d1c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
This is unnecessary because we can only get SIGPIPE if the reading end
of the pipe is closed. And that can only happen if the parent process
has exited, meaning there's no one to read our message anyway.
Change-Id: Ic90d8429a0eb4837971dfffd1664ec6821993ada
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
This should have been SIG_DFL, as we're about to execute a child
process. It's the child's responsibility to ignore SIGPIPE if it wants
to, or get killed by it when it writes to an pipe with no readers.
Qt itself does this for its own purposes (see qt_ignore_sigpipe() [until
I can get some time to teach Linux about O_NOSIGPIPE]). Therefore, we
ought to reset what we've done.
Change-Id: Ic90d8429a0eb4837971dfffd166585a686790dde
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
And set *pid to -1.
[ChangeLog][QtCore][QProcess] If a startDetached() fails to start the
target application, the QProcess object should now have a proper error
string in errorString().
Pick-to: 6.1
Change-Id: Ic90d8429a0eb4837971dfffd1664e825ffcb923e
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
That qWarning cannot be in the child process (we don't know if a user
logger is fork-no-exec-safe) and the failure to chdir() should be
reported as a failure in QProcess::startDetached() instead.
Change-Id: Ic90d8429a0eb4837971dfffd1664e7577c81610b
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: David Llewellyn-Jones <david.llewellyn-jones@jolla.com>
That only created an opportunity for qWarning(), which should never be
in the child process in the first place.
Change-Id: Ic90d8429a0eb4837971dfffd1664e57a2291ea78
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: David Llewellyn-Jones <david.llewellyn-jones@jolla.com>
To minimize code duplication, move the socket notifier deletion to the
closeChannel() function, where the pipe descriptor will be closed.
Change-Id: If75ba1c955c706ae6e2b3d9f53f7a25e4aa32fa7
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Otherwise, the user may receive the readyRead() signal just before
started().
Change-Id: I8d6fd18fdfcef0580a3e609100198b03b18b1175
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
The completion of the child process can take place asynchronously or in
one of the waitFor...() functions. In both cases, we used the same
handler (_q_processDied()), which caused several problems:
a. technically, waitForReadyRead() should have taken into account the
result of the calls to _q_canRead...() slots inside the
_q_processDied() function:
- the user calls waitForReadyRead();
- forkfd descriptor becomes signaled, while a grandchild
process is still alive;
- as readyRead() signal has not been emitted, _q_processDied()
is called;
- the grandchild process writes to stdout pipe;
- now data arrives, and _q_processDied() will collect it, but
won't report it.
b. we had a bug with recursions on Unix:
- death notification comes asynchronously;
- waitForDeadChild() closes forkfd;
- _q_canRead...() emits readyRead();
- a slot connected to readyRead() calls waitForFinished();
- waitForFinished() hangs (forkfd == -1).
c. for blocking functions, drainOutputPipes() was called twice on
Windows.
By introducing a new processFinished() function, we leave the read
operations in the _q_processDied() slot, while the process completion
code is guaranteed to run only once.
Change-Id: I5f9d09bc68a058169de4d9e490b48fc0b35e94cd
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
There is no reason to have the startup notifier and the death notifier
be active at the same time, as the former will detect death as well.
Previously, these notifiers were racing, but _q_processDied() ordered
signals by calling _q_startupNotification() manually. Thus, the
started()/finished() sequence was always emitted if the child process
was killed anywhere. Now this ordering is simply not necessary anymore.
This makes it possible to reuse the startup notifier for death
notification.
Change-Id: I5ebed9b5f28b19fe56c80498977a3b21be9288fd
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
[ChangeLog][QtCore][QProcess] Added support for QProcess::MergedChannels
mode with startDetached().
Change-Id: I953ad2063322015332269522a297f8e2842e438c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
We have the same channel forwarding, redirecting, and merging rules for
all platforms. This makes it possible to introduce the openChannels()
function, which consolidates the logic and performs high-level general
processing of the channels configuration properties.
Change-Id: Id3574fc42a56829328369b6a1a6ec9c95fce8eca
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
By using new QSocketNotifier API, we can avoid unnecessarily enabling
the notifier right before turning it off again.
Change-Id: Ie0dea00251e9885653677c495dfc5abaaa4db1c7
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
The child process inherits a standard handle of the main process in
such cases:
stdin - inputChannelMode == QProcess::ForwardedInputChannel,
stdout - processChannelMode == QProcess::ForwardedChannels ||
processChannelMode == QProcess::ForwardedOutputChannel,
stderr - processChannelMode == QProcess::ForwardedChannels ||
processChannelMode == QProcess::ForwardedErrorChannel ||
processChannelMode == QProcess::MergedChannels
For these combinations we should not create pipes and notifiers as
they would not be used.
Change-Id: I8e3836e4d840a40b338c85c54645539ebcaab3f6
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
It makes no sense to poll the I/O pipes if we didn't get a start-up
notification yet. And in fact, all waitFor...() functions except
waitForReadyRead() did already explicitly wait for process startup
completion. So fix that one up, and remove the handling of 'Starting'
state from the I/O loops.
Change-Id: Ibb7eb7c768bef3f9b6c54009c73b91775570102c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Replacing QElapsedTimer with QDeadlineTimer simplifies the code in
waiting functions, which also improves readability.
Change-Id: I56aedd356b547b6735ed0985dc81be706e292437
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Both on Unix and Windows, _q_processDied() unconditionally releases all
resources associated with the terminated child process, resets QProcess
to the initial state, and emits finished() signal. Thus, we can omit
reporting success, which also eliminates the related checks from
callers.
Change-Id: I40e32d1a9ccc8d488be6badba934355d734a8abd
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
QProcessPrivate::tryReadFromChannel() returns 'true' only if we emitted
readyRead() signal on the current read channel. Thus, these additional
checks are unnecessary.
Change-Id: Id98620cd08ee8808f60539c009986b869e517ef0
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
this implements a suggestion made by a comment that got lost in
028ddf363: as explained in 97645478's commit message, we were forcing
use of fork() because we couldn't be sure that the code in a custom
setupChildProcess() did not rely on pthread_atfork() callbacks being
called.
however, that in turn was inconsistent with the default behavior, and
made customizing QProcess mutually exclusive with benefitting from
forkfd().
use the opportunity presented by changing the method of modifying child
process behavior to also change this.
this also amends 4e2f4670, as most of the now deleted comment in fact
related to the use of vfork semantics, which we don't do anymore.
[ChangeLog][Important Behavior Changes][QtCore][QProcess][Unix]
pthread_atfork() callbacks are consistently not invoked on reasonably
recent Linux and FreeBSD systems any more. This was already the case in
later Qt 5 releases, unless setupChildProcess() was overridden.
Change-Id: Icb239e4d2c705bf4665589469022a521267f7db5
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
It can happen under unspecified conditions, see relevant ticket.
Task-number: QTBUG-86285
Pick-to: 5.15
Change-Id: I1f77bf0061a0faaa60283bb93fc3d82031247d54
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
It is not used in public API any more since
0f8848b7e25e4d8fb9265ff6e0aa31946addd741.
Replace by an internal Windows-specific Q_PROCESS_INFORMATION typedef.
Change-Id: Ia6dcc83ca667c40ac5d678c00d143c09d650e42a
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Our CI cross-compiling arm qemu builds have issues in tests that use
QProcess, due to user-space qemu seemingly not supporting pidfds
properly.
Add a 'forkfd_pidfd' configure.json feature, which can be manually
disabled when configuring Qt, causing QProcess to do a regular fork
instead of using the new pidfd kernel feature.
This will help us avoid the regression of multiple tests failing on
the new Ubuntu 20.04 CI host images when they are run via qemu.
Task-number: QTBUG-86285
Task-number: QTBUG-86187
Task-number: QTBUG-86198
Change-Id: Ib2209d7e95126e0fb738bf59e39070d5a62c482f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
[ChangeLog][Source-Incompatible Changes] QProcess::setupChildProcess()
was removed. To execute code in a child process, use
QProcess::setChildProcessModifier()
[ChangeLog][QtCore][QProcess] Added setChildProcessModifier() function
with which one can provide code to be run in the Unix child process
between fork() and execve(). With this function, it is no longer
necessary to derive from QProcess in order to execute actions in the
child process.
Another reason is that we can tell whether the std::function carries a
valid target much more easily than we can tell whether QProcess was
overridden.
The setupChildProcess() virtual function does not need to be marked
final, since no overrider could ever return an inaccessible private
class. This also makes sure the error presented to the user is about the
return type, not about attempting to override a final.
Clang:
error: virtual function 'f' has a different return type ('void') than the function it overrides (which has return type 'QProcess::Use_setChildProcessModifier_Instead')
GCC:
error: conflicting return type specified for 'virtual void MyProcess::setupChildProcess()'
note: overridden function is 'virtual QProcess::Use_setChildProcessModifier_Instead QProcess::setupChildProcess()'
ICC:
error: return type is neither identical to nor covariant with return type "QProcess::Use_setChildProcessModifier_Instead" of overridden virtual function "QProcess::setupChildProcess"
MSVC is not relevant since it doesn't compile to Unix.
Change-Id: Ia8b65350cd5d49debca9fffd15f801161363aea7
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
This will never work, not unless libc implements it
themselves, since the child process is not allowed to return
from the function that does the vfork(), as subsequent use
of the stack would trash the frozen parent's return address,
and in our case that's syscall(). Instead, we may add a
vforkfd() function that takes a callback function that will
be called in that context, like the glibc clone(3) wrapper
does.
Pick-to: 5.15
Change-Id: I1dba29bc0f454df09ca1fffd161800b453c00593
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
The pre-existing overload passes an int, but this can mean the
descriptor gets truncated in compilations where the descriptor
is 64-bit.
The old overload with int is visible when querying the metaobject system
so string-based connects still work as before, and connecting to it will
produce a deprecation warning in the output.
At the same time the PMF-based connect will, on recompile, pick the
QSocketDescriptor overload. As an added improvement it also comes with
the notification type, removing the need for separate slots where the
code would be mostly shared anyway.
The QSocketDescriptor type can be implicitly converted to and from
qintptr to ensure existing code still compiles. It can also be
constructed from Qt::HANDLE on Windows.
In this same patch I also update the existing string-based connects in
this module, which then includes updating the parameters for some slots
as well.
[ChangeLog][QtCore][QSocketNotifier] Added
QSocketNotifier::activated(QSocketDescriptor, QSocketNotifier::Type).
This replaces the activated(int) signal which in 64-bit environments
could truncate the socket descriptor. If you use "activated" with the
string-based connect() then you need to update the parameter type of the
signal and slot if it had one. If you use it with the pointer to member
function based connect() then all you need to do is update your slot's
parameter type if it has one. If you need to compile your source code
with multiple versions of Qt then connect() to this function using
pointer to member function and update the slot's parameter type if
needed.
Task-number: QTBUG-70441
Change-Id: Ic43d6bc4c5bcb4040867b2ffad8d36fb01eed8af
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
... when we are not using the FFD_USE_FORK flag. We use the FFD_USE_FORK
flag when we have user code to run in setupChildProcess(). This code is
enabled for all Unix, but forkfd() honors this flag only on Linux >=
5.4.
See the commit adding the flag for more information on what the flag
does and see the comment in this commit on why it's safe to use it.
Fixes: QTBUG-17331
Change-Id: I1bee3bc466a04f19bd6efffd15f448cb23ce1e91
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
If the user derived from QProcess, it's likely to override the
setupChildProcess() virtual. Unlike fork(), the system calls for
enhenced functionality (FreeBSD pdfork() and Linux's clone()) won't call
pthread_atfork() callbacks and the environment in the child process
could be inconsistent. Qt's own code is safe, but we can't make the same
statement about users' code.
So we err on the safe side for correctness and run the old, less safe
implementation (thread-unsafe, subject to hijacking of the signal
handler, etc.).
Change-Id: Ia2aa807ffa8a4c798425fffd15d9703bd03f6f09
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
