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authorThiago Macieira <thiago.macieira@intel.com>2017-06-30 12:30:45 -0700
committerThiago Macieira <thiago.macieira@intel.com>2017-07-08 02:18:14 +0000
commit3c689c4b3fd24ead8726444723536452d0e89d85 (patch)
treec1d5718cdb4f109f34f7d1e9e78eb482b84369c8
parent49ab284d3445c61a0ea819bbe2dd2ed54241d2e9 (diff)
QLockFile: Move the check for Linux /proc to a central place
I'll need it soon in QTemporaryFile. This also reduces the overhead, since QFile::exists -> QFileInfo::exists needs to check if there's a file engine that handles "/proc/version" (there isn't), convert the UTF-16 filename to UTF-8 and QFileSystemEngine::fillMetaData will issue a more expensive stat(2) syscall. access(2) is cheaper. This commit also introduces QT_LINUX_ALWAYS_HAVE_PROCFS that isn't defined anywhere, but could be passed during configure with -D if a build wants it. Change-Id: I1eba2b016de74620bfc8fffd14ccfd1593d59ade Reviewed-by: Lars Knoll <lars.knoll@qt.io>
-rw-r--r--src/corelib/io/qlockfile_unix.cpp4
-rw-r--r--src/corelib/kernel/qcore_unix_p.h15
2 files changed, 17 insertions, 2 deletions
diff --git a/src/corelib/io/qlockfile_unix.cpp b/src/corelib/io/qlockfile_unix.cpp
index ccc607afd5..f21aced87c 100644
--- a/src/corelib/io/qlockfile_unix.cpp
+++ b/src/corelib/io/qlockfile_unix.cpp
@@ -199,7 +199,7 @@ QLockFile::LockError QLockFilePrivate::tryLock_sys()
}
if (qt_write_loop(fd, fileData.constData(), fileData.size()) < fileData.size()) {
- close(fd);
+ qt_safe_close(fd);
if (!QFile::remove(fileName))
qWarning("QLockFile: Could not remove our own lock file %s.", qPrintable(fileName));
return QLockFile::UnknownError; // partition full
@@ -258,7 +258,7 @@ QString QLockFilePrivate::processNameByPid(qint64 pid)
proc_name(pid, name, sizeof(name) / sizeof(char));
return QFile::decodeName(name);
#elif defined(Q_OS_LINUX)
- if (!QFile::exists(QStringLiteral("/proc/version")))
+ if (!qt_haveLinuxProcfs())
return QString();
char exePath[64];
char buf[PATH_MAX + 1];
diff --git a/src/corelib/kernel/qcore_unix_p.h b/src/corelib/kernel/qcore_unix_p.h
index eca575ba01..ea5d98cbf3 100644
--- a/src/corelib/kernel/qcore_unix_p.h
+++ b/src/corelib/kernel/qcore_unix_p.h
@@ -340,6 +340,21 @@ static inline pid_t qt_safe_waitpid(pid_t pid, int *status, int options)
timespec qt_gettime() Q_DECL_NOTHROW;
void qt_nanosleep(timespec amount);
+/* non-static */
+inline bool qt_haveLinuxProcfs()
+{
+#ifdef Q_OS_LINUX
+# ifdef QT_LINUX_ALWAYS_HAVE_PROCFS
+ return true;
+# else
+ static const bool present = (access("/proc/version", F_OK) == 0);
+ return present;
+# endif
+#else
+ return false;
+#endif
+}
+
Q_CORE_EXPORT int qt_safe_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout_ts);
static inline int qt_poll_msecs(struct pollfd *fds, nfds_t nfds, int timeout)