diff options
authorJoerg Bornemann <>2014-03-06 14:21:53 +0100
committerThe Qt Project <>2014-03-07 23:53:13 +0100
commitf15d9e6ccd006a2b47b50ae755fbe9534748a2eb (patch)
parentbf0336a02502b3ed4d399c1cf5b4a56b1e858d42 (diff)
do not use fileno calls in forked childold/5.2
This fixes an issue that causes QProcess::start to silently fail on OS X 10.9. Apparently, fileno(stdout) locks the handle on OS X 10.9. It may happen that the parent process fflush()s stdout while the child has just been forked. The stdout lock of the parent is never released in the child and fileno(stdout) therefore locks forever. According to the fork documentation on one may only call async-signal-safe functions between fork and exec in the child. The fileno() function does not appear in the list of async-signal-safe functions. Also, fileno(stdout) and friends can be easily replaced by the standard constants STDOUT_FILENO etc. Done-with: Fawzi Mohamed <> Task-number: QTBUG-37306 Change-Id: I2b1f5f47cc48a1ad020fb0493a955d2bc27aeb47 Reviewed-by: Thiago Macieira <> (cherry picked from b2216bbe06b8be2bef6d8bc2ffff1337f6d23358)
1 files changed, 4 insertions, 4 deletions
diff --git a/src/corelib/io/qprocess_unix.cpp b/src/corelib/io/qprocess_unix.cpp
index 3c6d294916..8add9c56a7 100644
--- a/src/corelib/io/qprocess_unix.cpp
+++ b/src/corelib/io/qprocess_unix.cpp
@@ -880,18 +880,18 @@ void QProcessPrivate::execChild(const char *workingDir, char **path, char **argv
// copy the stdin socket if asked to (without closing on exec)
if (inputChannelMode != QProcess::ForwardedInputChannel)
- qt_safe_dup2(stdinChannel.pipe[0], fileno(stdin), 0);
+ qt_safe_dup2(stdinChannel.pipe[0], STDIN_FILENO, 0);
// copy the stdout and stderr if asked to
if (processChannelMode != QProcess::ForwardedChannels) {
if (processChannelMode != QProcess::ForwardedOutputChannel)
- qt_safe_dup2(stdoutChannel.pipe[1], fileno(stdout), 0);
+ qt_safe_dup2(stdoutChannel.pipe[1], STDOUT_FILENO, 0);
// merge stdout and stderr if asked to
if (processChannelMode == QProcess::MergedChannels) {
- qt_safe_dup2(fileno(stdout), fileno(stderr), 0);
+ qt_safe_dup2(STDOUT_FILENO, STDERR_FILENO, 0);
} else if (processChannelMode != QProcess::ForwardedErrorChannel) {
- qt_safe_dup2(stderrChannel.pipe[1], fileno(stderr), 0);
+ qt_safe_dup2(stderrChannel.pipe[1], STDERR_FILENO, 0);