From c5f83fbd89d6bb950fb012c285879f6c88b5bdf3 Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Wed, 22 Apr 2009 16:47:12 +0200 Subject: Add qcore_unix_p.h containing mostly safe versions of Unix functions. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Most of these functions are from unistd.h and need to have a loop around the actual call because the calls can be interrupted by a signal delivery. Some special calls (open, dup2, pipe) require an extra flag to support thread-safe execution: the file descriptor must be created from the operating system with the FD_CLOEXEC flag already set. The O_CLOEXEC flag is specified in POSIX.1-2008, but the rest is Linux-specific. Reviewed-By: João Abecasis --- src/corelib/kernel/kernel.pri | 1 + src/corelib/kernel/qcore_unix_p.h | 246 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 247 insertions(+) create mode 100644 src/corelib/kernel/qcore_unix_p.h diff --git a/src/corelib/kernel/kernel.pri b/src/corelib/kernel/kernel.pri index ecef555..6f28029 100644 --- a/src/corelib/kernel/kernel.pri +++ b/src/corelib/kernel/kernel.pri @@ -92,6 +92,7 @@ unix { kernel/qsharedmemory_unix.cpp \ kernel/qsystemsemaphore_unix.cpp HEADERS += \ + kernel/qcore_unix_p.h \ kernel/qcrashhandler_p.h contains(QT_CONFIG, glib) { diff --git a/src/corelib/kernel/qcore_unix_p.h b/src/corelib/kernel/qcore_unix_p.h new file mode 100644 index 0000000..4e3158a --- /dev/null +++ b/src/corelib/kernel/qcore_unix_p.h @@ -0,0 +1,246 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#ifndef QCORE_UNIX_P_H +#define QCORE_UNIX_P_H + +// +// W A R N I N G +// ------------- +// +// This file is not part of the Qt API. It exists for the convenience +// of Qt code on Unix. This header file may change from version to +// version without notice, or even be removed. +// +// We mean it. +// + +#include "qplatformdefs.h" + +#ifndef Q_OS_UNIX +# error "qcore_unix_p.h included on a non-Unix system" +#endif + +#include +#include +#include + +#include +#include +#include + +QT_BEGIN_NAMESPACE + +#if defined(Q_OS_LINUX) && defined(__GLIBC__) && (__GLIBC__ * 0x100 + __GLIBC_MINOR__) >= 0x0209 +# define QT_UNIX_SUPPORTS_THREADSAFE_CLOEXEC 1 +#else +# define QT_UNIX_SUPPORTS_THREADSAFE_CLOEXEC 0 +#endif + +#define EINTR_LOOP(var, cmd) \ + do { \ + var = cmd; \ + } while (var == -1 && errno == EINTR) + + +// don't call QT_OPEN or ::open +// call qt_safe_open +static inline int qt_safe_open(const char *pathname, int flags, mode_t mode = 0777) +{ +#ifdef O_CLOEXEC + flags |= O_CLOEXEC; +#endif + register int fd; + EINTR_LOOP(fd, QT_OPEN(pathname, flags, mode)); + + // unknown flags are ignored, so we have no way of verifying if + // O_CLOEXEC was accepted + if (fd != -1) + ::fcntl(fd, F_SETFD, FD_CLOEXEC); + return fd; +} +#undef QT_OPEN +#define QT_OPEN qt_safe_open + +// don't call ::pipe +// call qt_safe_pipe +static inline int qt_safe_pipe(int pipefd[2], int flags = 0) +{ +#ifdef O_CLOEXEC + Q_ASSERT((flags & ~(O_CLOEXEC | O_NONBLOCK)) == 0); +#else + Q_ASSERT((flags & ~O_NONBLOCK) == 0); +#endif + + register int ret; +#if QT_UNIX_SUPPORTS_THREADSAFE_CLOEXEC + // use pipe2 + flags |= O_CLOEXEC; + ret = ::pipe2(pipefd, flags); // pipe2 is Linux-specific and is documented not to return EINTR + if (ret == 0 || errno != ENOSYS) + return ret; +#endif + + ret = ::pipe(pipefd); + if (ret == -1) + return -1; + + ::fcntl(pipefd[0], F_SETFD, FD_CLOEXEC); + ::fcntl(pipefd[1], F_SETFD, FD_CLOEXEC); + + // set non-block too? + if (flags & O_NONBLOCK) { + ::fcntl(pipefd[0], F_SETFL, ::fcntl(pipefd[0], F_GETFL) | O_NONBLOCK); + ::fcntl(pipefd[1], F_SETFL, ::fcntl(pipefd[1], F_GETFL) | O_NONBLOCK); + } + + return 0; +} + +// don't call dup or fcntl(F_DUPFD) +static inline int qt_safe_dup(int oldfd, int atleast = 0, int flags = FD_CLOEXEC) +{ + Q_ASSERT(flags == FD_CLOEXEC || flags == 0); + + register int ret; +#ifdef F_DUPFD_CLOEXEC + // use this fcntl + if (flags & FD_CLOEXEC) { + ret = ::fcntl(oldfd, F_DUPFD_CLOEXEC, atleast); + if (ret != -1 || errno != EINVAL) + return ret; + } +#endif + + // use F_DUPFD + ret = ::fcntl(oldfd, F_DUPFD, atleast); + + if (flags && ret != -1) + ::fcntl(ret, F_SETFD, flags); + return ret; +} + +// don't call dup2 +// call qt_safe_dup2 +static inline int qt_safe_dup2(int oldfd, int newfd, int flags = FD_CLOEXEC) +{ + Q_ASSERT(flags == FD_CLOEXEC || flags == 0); + + register int ret; +#if QT_UNIX_SUPPORTS_THREADSAFE_CLOEXEC + // use dup3 + if (flags & FD_CLOEXEC) { + EINTR_LOOP(ret, ::dup3(oldfd, newfd, O_CLOEXEC)); + if (ret == 0 || errno != ENOSYS) + return ret; + } +#endif + EINTR_LOOP(ret, ::dup2(oldfd, newfd)); + if (ret == -1) + return -1; + + if (flags) + ::fcntl(newfd, F_SETFD, flags); + return 0; +} + +static inline qint64 qt_safe_read(int fd, char *data, qint64 maxlen) +{ + qint64 ret = 0; + EINTR_LOOP(ret, QT_READ(fd, data, maxlen)); + return ret; +} +#undef QT_READ +#define QT_READ qt_safe_read + +static inline qint64 qt_safe_write(int fd, const char *data, qint64 len) +{ + qint64 ret = 0; + EINTR_LOOP(ret, QT_WRITE(fd, data, len)); + return ret; +} +#undef QT_WRITE +#define QT_WRITE qt_safe_write + +static inline int qt_safe_close(int fd) +{ + register int ret; + EINTR_LOOP(ret, QT_CLOSE(fd)); + return ret; +} +#undef QT_CLOSE +#define QT_CLOSE qt_safe_close + +static inline int qt_safe_execve(const char *filename, char *const argv[], + char *const envp[]) +{ + register int ret; + EINTR_LOOP(ret, ::execve(filename, argv, envp)); + return ret; +} + +static inline int qt_safe_execv(const char *path, char *const argv[]) +{ + register int ret; + EINTR_LOOP(ret, ::execv(path, argv)); + return ret; +} + +static inline int qt_safe_execvp(const char *file, char *const argv[]) +{ + register int ret; + EINTR_LOOP(ret, ::execvp(file, argv)); + return ret; +} + +static inline pid_t qt_safe_waitpid(pid_t pid, int *status, int options) +{ + register int ret; + EINTR_LOOP(ret, ::waitpid(pid, status, options)); + return ret; +} + +Q_CORE_EXPORT int qt_safe_select(int nfds, fd_set *fdread, fd_set *fdwrite, fd_set *fdexcept, + const struct timeval *tv); + +QT_END_NAMESPACE + +#endif -- cgit v0.12