implement POSIX IPC based QLock, QWSLock and QWSSharedMemory backends

Merge-request: 1259
Reviewed-by: Harald Fernengel <harald.fernengel@nokia.com>

8 files changed, 287 insertions, 30 deletions

diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index c927556e41..c7b0b505bf 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -2746,13 +2746,6 @@ QT_LICENSED_MODULE(DBus)
 #  define QT_NO_CONCURRENT_FILTER
 #endif
 
-#ifdef Q_OS_QNX
-// QNX doesn't have SYSV style shared memory. Multiprocess QWS apps
-// and shared fonts are not available
-#  define QT_NO_QWS_MULTIPROCESS
-#  define QT_NO_QWS_SHARE_FONTS
-#endif
-
 #if defined (__ELF__)
 #  if defined (Q_OS_LINUX) || defined (Q_OS_SOLARIS) || defined (Q_OS_FREEBSD) || defined (Q_OS_OPENBSD) || defined (Q_OS_IRIX)
 #    define Q_OF_ELF
diff --git a/src/gui/embedded/qlock.cpp b/src/gui/embedded/qlock.cpp
index ac154313cf..eaad15c40c 100644
--- a/src/gui/embedded/qlock.cpp
+++ b/src/gui/embedded/qlock.cpp
@@ -41,7 +41,6 @@
 
 #include "qlock_p.h"
 
-
 #ifdef QT_NO_QWS_MULTIPROCESS
 
 QT_BEGIN_NAMESPACE
@@ -83,7 +82,7 @@ QT_END_NAMESPACE
 #else // QT_NO_QWS_MULTIPROCESS
 
 #if defined(Q_OS_DARWIN)
-#  define Q_NO_SEMAPHORE
+#  define QT_NO_SEMAPHORE
 #endif
 
 #include "qwssignalhandler_p.h"
@@ -91,11 +90,13 @@ QT_END_NAMESPACE
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/ipc.h>
-#if defined(Q_NO_SEMAPHORE)
+#if defined(QT_NO_SEMAPHORE)
 #  include <sys/stat.h>
 #  include <sys/file.h>
-#else
+#elif !defined(QT_POSIX_IPC)
 #  include <sys/sem.h>
+#else
+#  include <semaphore.h>
 #endif
 #include <string.h>
 #include <errno.h>
@@ -109,17 +110,24 @@ QT_BEGIN_NAMESPACE
 class QLockData
 {
 public:
-#ifdef Q_NO_SEMAPHORE
+#if defined(QT_NO_SEMAPHORE) || defined(QT_POSIX_IPC)
     QByteArray file;
-#endif // Q_NO_SEMAPHORE
+#endif
+#if !defined(QT_POSIX_IPC)
     int id;
+#else
+    sem_t *id;    // Read mode resource counter
+    sem_t *rsem;  // Read mode lock
+    sem_t *wsem;  // Write mode lock
+#endif
     int count;
     bool owned;
 };
 
+
 /*!
     \class QLock
-    \brief The QLock class is a wrapper for a System V shared semaphore.
+    \brief The QLock class is a wrapper for a system shared semaphore.
 
     \ingroup qws
 
@@ -148,7 +156,7 @@ QLock::QLock(const QString &filename, char id, bool create)
 {
     data = new QLockData;
     data->count = 0;
-#ifdef Q_NO_SEMAPHORE
+#if defined(QT_NO_SEMAPHORE)
     data->file = filename.toLocal8Bit() + id;
     for (int x = 0; x < 2; ++x) {
         data->id = QT_OPEN(data->file.constData(), O_RDWR | (x ? O_CREAT : 0), S_IRWXU);
@@ -157,7 +165,7 @@ QLock::QLock(const QString &filename, char id, bool create)
             break;
         }
     }
-#else
+#elif !defined(QT_POSIX_IPC)
     key_t semkey = ftok(filename.toLocal8Bit().constData(), id);
     data->id = semget(semkey, 0, 0);
     data->owned = create;
@@ -170,6 +178,28 @@ QLock::QLock(const QString &filename, char id, bool create)
         arg.val = MAX_LOCKS;
         semctl(data->id, 0, SETVAL, arg);
     }
+#else
+    data->file = filename.toLocal8Bit() + id;
+    data->owned = create;
+
+    char ids[3] = { 'c', 'r', 'w' };
+    sem_t **sems[3] = { &data->id, &data->rsem, &data->wsem };
+    unsigned short initialValues[3] = { MAX_LOCKS, 1, 1 };
+    for (int i = 0; i < 3; ++i) {
+        QByteArray file = data->file + ids[i];
+        do {
+            *sems[i] = sem_open(file.constData(), 0, 0666, 0);
+        } while (*sems[i] == SEM_FAILED && errno == EINTR);
+        if (create) {
+            if (*sems[i] != SEM_FAILED) {
+                sem_close(*sems[i]);
+                sem_unlink(file.constData());
+            }
+            do {
+                *sems[i] = sem_open(file.constData(), O_CREAT, 0666, initialValues[i]);
+            } while (*sems[i] == SEM_FAILED && errno == EINTR);
+        }
+    }
 #endif
     if (!isValid()) {
         qWarning("QLock::QLock: Cannot %s semaphore %s '%c' (%d, %s)",
@@ -193,17 +223,32 @@ QLock::~QLock()
 
     while (locked())
         unlock();
-#ifdef Q_NO_SEMAPHORE
+
+#if defined(QT_NO_SEMAPHORE)
     if (isValid())
         QT_CLOSE(data->id);
+#elif defined(QT_POSIX_IPC)
+    if (data->id != SEM_FAILED)
+        sem_close(data->id);
+    if (data->rsem != SEM_FAILED)
+        sem_close(data->rsem);
+    if (data->wsem != SEM_FAILED)
+        sem_close(data->wsem);
 #endif
+
     if (data->owned) {
-#ifdef Q_NO_SEMAPHORE
+#if defined(QT_NO_SEMAPHORE)
         unlink(data->file.constData());
-#else
+#elif !defined(QT_POSIX_IPC)
         qt_semun semval;
         semval.val = 0;
         semctl(data->id, 0, IPC_RMID, semval);
+#else
+        char ids[3] = { 'c', 'r', 'w' };
+        for (int i = 0; i < 3; ++i) {
+            QByteArray file = data->file + ids[i];
+            sem_unlink(file.constData());
+        }
 #endif
     }
     delete data;
@@ -216,7 +261,11 @@ QLock::~QLock()
 */
 bool QLock::isValid() const
 {
+#if !defined(QT_POSIX_IPC)
     return data && data->id != -1;
+#else
+    return data && data->id != SEM_FAILED && data->rsem != SEM_FAILED && data->wsem != SEM_FAILED;
+#endif
 }
 
 /*!
@@ -232,21 +281,48 @@ bool QLock::isValid() const
 */
 void QLock::lock(Type t)
 {
+    if (!isValid())
+        return;
+
     if (!data->count) {
         type = t;
 
         int rv;
-#ifdef Q_NO_SEMAPHORE
+#if defined(QT_NO_SEMAPHORE)
         int op = type == Write ? LOCK_EX : LOCK_SH;
 
         EINTR_LOOP(rv, flock(data->id, op));
-#else
+#elif !defined(QT_POSIX_IPC)
         sembuf sops;
         sops.sem_num = 0;
         sops.sem_op = type == Write ? -MAX_LOCKS : -1;
         sops.sem_flg = SEM_UNDO;
 
         EINTR_LOOP(rv, semop(data->id, &sops, 1));
+#else
+        if (type == Write) {
+            EINTR_LOOP(rv, sem_wait(data->rsem));
+            if (rv != -1) {
+                EINTR_LOOP(rv, sem_wait(data->wsem));
+                if (rv == -1)
+                    sem_post(data->rsem);
+            }
+        } else {
+            EINTR_LOOP(rv, sem_wait(data->wsem));
+            if (rv != -1) {
+                EINTR_LOOP(rv, sem_trywait(data->rsem));
+                if (rv != -1 || errno == EAGAIN) {
+                    EINTR_LOOP(rv, sem_wait(data->id));
+                    if (rv == -1) {
+                        int semval;
+                        sem_getvalue(data->id, &semval);
+                        if (semval == MAX_LOCKS)
+                            sem_post(data->rsem);
+                    }
+                }
+                rv = sem_post(data->wsem);
+            }
+        }
 #endif
         if (rv == -1) {
             qDebug("QLock::lock(): %s", strerror(errno));
@@ -265,19 +341,37 @@ void QLock::lock(Type t)
 */
 void QLock::unlock()
 {
-    if (data->count) {
+    if (!isValid())
+        return;
+
+    if (data->count > 0) {
         data->count--;
         if (!data->count) {
             int rv;
-#ifdef Q_NO_SEMAPHORE
+#if defined(QT_NO_SEMAPHORE)
             EINTR_LOOP(rv, flock(data->id, LOCK_UN));
-#else
+#elif !defined(QT_POSIX_IPC)
             sembuf sops;
             sops.sem_num = 0;
             sops.sem_op = type == Write ? MAX_LOCKS : 1;
             sops.sem_flg = SEM_UNDO;
 
             EINTR_LOOP(rv, semop(data->id, &sops, 1));
+#else
+            if (type == Write) {
+                sem_post(data->wsem);
+                rv = sem_post(data->rsem);
+            } else {
+                EINTR_LOOP(rv, sem_wait(data->wsem));
+                if (rv != -1) {
+                    sem_post(data->id);
+                    int semval;
+                    sem_getvalue(data->id, &semval);
+                    if (semval == MAX_LOCKS)
+                        sem_post(data->rsem);
+                    rv = sem_post(data->wsem);
+                }
+            }
 #endif
             if (rv == -1)
                 qDebug("QLock::unlock(): %s", strerror(errno));
diff --git a/src/gui/embedded/qwslock.cpp b/src/gui/embedded/qwslock.cpp
index c14f50b1ae..f9ea0002f4 100644
--- a/src/gui/embedded/qwslock.cpp
+++ b/src/gui/embedded/qwslock.cpp
@@ -45,12 +45,15 @@
 
 #include "qwssignalhandler_p.h"
 
+#include <stdint.h>
 #include <stdio.h>
 #include <errno.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/ipc.h>
+#ifndef QT_POSIX_IPC
 #include <sys/sem.h>
+#endif
 #include <sys/time.h>
 #include <time.h>
 #ifdef Q_OS_LINUX
@@ -66,6 +69,12 @@ QT_BEGIN_NAMESPACE
 #error QWSLock currently requires semaphores
 #endif
 
+#ifdef QT_POSIX_IPC
+#include <QtCore/QAtomicInt>
+
+static QBasicAtomicInt localUniqueId = Q_BASIC_ATOMIC_INITIALIZER(1);
+#endif
+
 QWSLock::QWSLock(int id) : semId(id)
 {
     static unsigned short initialValues[3] = { 1, 1, 0 };
@@ -74,6 +83,7 @@ QWSLock::QWSLock(int id) : semId(id)
     QWSSignalHandler::instance()->addWSLock(this);
 #endif
 
+#ifndef QT_POSIX_IPC
     if (semId == -1) {
         semId = semget(IPC_PRIVATE, 3, IPC_CREAT | 0666);
         if (semId == -1) {
@@ -88,6 +98,30 @@ QWSLock::QWSLock(int id) : semId(id)
             qFatal("Unable to initialize semaphores");
         }
     }
+#else
+    sems[0] = sems[1] = sems[2] = SEM_FAILED;
+    owned = false;
+
+    if (semId == -1) {
+        // ### generate really unique IDs
+        semId = (getpid() << 16) + (localUniqueId.fetchAndAddRelaxed(1) % ushort(-1));
+        owned = true;
+    }
+
+    QByteArray pfx = "/qwslock_" + QByteArray::number(semId, 16) + '_';
+    QByteArray keys[3] = { pfx + "BackingStore", pfx + "Communication", pfx + "RegionEvent" };
+    for (int i = 0; i < 3; ++i) {
+        if (owned)
+            sem_unlink(keys[i].constData());
+        do {
+            sems[i] = sem_open(keys[i].constData(), (owned ? O_CREAT : 0), 0666, initialValues[i]);
+        } while (sems[i] == SEM_FAILED && errno == EINTR);
+        if (sems[i] == SEM_FAILED) {
+            perror("QWSLock::QWSLock");
+            qFatal("Unable to %s semaphore", (owned ? "create" : "open"));
+        }
+    }
+#endif
 
     lockCount[0] = lockCount[1] = 0;
 }
@@ -99,10 +133,27 @@ QWSLock::~QWSLock()
 #endif
 
     if (semId != -1) {
+#ifndef QT_POSIX_IPC
         qt_semun semval;
         semval.val = 0;
         semctl(semId, 0, IPC_RMID, semval);
         semId = -1;
+#else
+        // emulate the SEM_UNDO behavior for the BackingStore lock
+        while (hasLock(BackingStore))
+            unlock(BackingStore);
+
+        QByteArray pfx = "/qwslock_" + QByteArray::number(semId, 16) + '_';
+        QByteArray keys[3] = { pfx + "BackingStore", pfx + "Communication", pfx + "RegionEvent" };
+        for (int i = 0; i < 3; ++i) {
+            if (sems[i] != SEM_FAILED) {
+                sem_close(sems[i]);
+                sems[i] = SEM_FAILED;
+            }
+            if (owned)
+                sem_unlink(keys[i].constData());
+        }
+#endif
     }
 }
 
@@ -110,6 +161,7 @@ bool QWSLock::up(unsigned short semNum)
 {
     int ret;
 
+#ifndef QT_POSIX_IPC
     sembuf sops = { semNum, 1, 0 };
     // As the BackingStore lock is a mutex, and only one process may own
     // the lock, it's safe to use SEM_UNDO. On the other hand, the
@@ -119,6 +171,9 @@ bool QWSLock::up(unsigned short semNum)
         sops.sem_flg |= SEM_UNDO;
 
     EINTR_LOOP(ret, semop(semId, &sops, 1));
+#else
+    ret = sem_post(sems[semNum]);
+#endif
     if (ret == -1) {
         qDebug("QWSLock::up(): %s", strerror(errno));
         return false;
@@ -131,6 +186,7 @@ bool QWSLock::down(unsigned short semNum, int)
 {
     int ret;
 
+#ifndef QT_POSIX_IPC
     sembuf sops = { semNum, -1, 0 };
     // As the BackingStore lock is a mutex, and only one process may own
     // the lock, it's safe to use SEM_UNDO. On the other hand, the
@@ -140,6 +196,9 @@ bool QWSLock::down(unsigned short semNum, int)
         sops.sem_flg |= SEM_UNDO;
 
     EINTR_LOOP(ret, semop(semId, &sops, 1));
+#else
+    EINTR_LOOP(ret, sem_wait(sems[semNum]));
+#endif
     if (ret == -1) {
         qDebug("QWSLock::down(): %s", strerror(errno));
         return false;
@@ -150,7 +209,13 @@ bool QWSLock::down(unsigned short semNum, int)
 
 int QWSLock::getValue(unsigned short semNum) const
 {
-    int ret = semctl(semId, semNum, GETVAL, 0);
+    int ret;
+#ifndef QT_POSIX_IPC
+    ret = semctl(semId, semNum, GETVAL, 0);
+#else
+    if (sem_getvalue(sems[semNum], &ret) == -1)
+        ret = -1;
+#endif
     if (ret == -1)
         qDebug("QWSLock::getValue(): %s", strerror(errno));
     return ret;
diff --git a/src/gui/embedded/qwslock_p.h b/src/gui/embedded/qwslock_p.h
index d020b22cb4..71a4cca9c4 100644
--- a/src/gui/embedded/qwslock_p.h
+++ b/src/gui/embedded/qwslock_p.h
@@ -57,6 +57,10 @@
 
 #ifndef QT_NO_QWS_MULTIPROCESS
 
+#ifdef QT_POSIX_IPC
+#  include <semaphore.h>
+#endif
+
 QT_BEGIN_NAMESPACE
 
 class QWSLock
@@ -80,6 +84,10 @@ private:
 
     int semId;
     int lockCount[2];
+#ifdef QT_POSIX_IPC
+    sem_t *sems[3];
+    bool owned;
+#endif
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/embedded/qwssharedmemory.cpp b/src/gui/embedded/qwssharedmemory.cpp
index a677626678..853de615dc 100644
--- a/src/gui/embedded/qwssharedmemory.cpp
+++ b/src/gui/embedded/qwssharedmemory.cpp
@@ -45,14 +45,37 @@
 
 #include <sys/types.h>
 #include <sys/ipc.h>
+#ifndef QT_POSIX_IPC
 #include <sys/shm.h>
+#else
+#include <sys/mman.h>
+#include <sys/stat.h>
+#endif
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <private/qcore_unix_p.h>
 
 //#define QT_SHM_DEBUG
 
 QT_BEGIN_NAMESPACE
 
+#ifdef QT_POSIX_IPC
+#include <QtCore/QAtomicInt>
+
+static QBasicAtomicInt localUniqueId = Q_BASIC_ATOMIC_INITIALIZER(1);
+
+static inline QByteArray makeKey(int id)
+{
+    return "/qwsshm_" + QByteArray::number(id, 16);
+}
+#endif
+
 QWSSharedMemory::QWSSharedMemory()
     : shmId(-1), shmBase(0), shmSize(0)
+#ifdef QT_POSIX_IPC
+    , hand(-1)
+#endif
 {
 }
 
@@ -66,19 +89,47 @@ bool QWSSharedMemory::create(int size)
     if (shmId != -1)
         detach();
 
+#ifndef QT_POSIX_IPC
     shmId = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600);
+#else
+    // ### generate really unique IDs
+    shmId = (getpid() << 16) + (localUniqueId.fetchAndAddRelaxed(1) % ushort(-1));
+    QByteArray shmName = makeKey(shmId);
+    EINTR_LOOP(hand, shm_open(shmName.constData(), O_RDWR | O_CREAT, 0660));
+    if (hand != -1) {
+        // the size may only be set once; ignore errors
+        int ret;
+        EINTR_LOOP(ret, ftruncate(hand, size));
+        if (ret == -1)
+            shmId = -1;
+    } else {
+        shmId = -1;
+    }
+#endif
     if (shmId == -1) {
 #ifdef QT_SHM_DEBUG
         perror("QWSSharedMemory::create():");
         qWarning("Error allocating shared memory of size %d", size);
 #endif
+        detach();
         return false;
     }
+
+#ifndef QT_POSIX_IPC
     shmBase = shmat(shmId, 0, 0);
     // On Linux, it is possible to attach a shared memory segment even if it
     // is already marked to be deleted. However, POSIX.1-2001 does not specify
     // this behaviour and many other implementations do not support it.
     shmctl(shmId, IPC_RMID, 0);
+#else
+    // grab the size
+    QT_STATBUF st;
+    if (QT_FSTAT(hand, &st) != -1) {
+        shmSize = st.st_size;
+        // grab the memory
+        shmBase = mmap(0, shmSize, PROT_READ | PROT_WRITE, MAP_SHARED, hand, 0);
+    }
+#endif
     if (shmBase == (void*)-1 || !shmBase) {
 #ifdef QT_SHM_DEBUG
         perror("QWSSharedMemory::create():");
@@ -102,7 +153,21 @@ bool QWSSharedMemory::attach(int id)
         return false;
 
     shmId = id;
+#ifndef QT_POSIX_IPC
     shmBase = shmat(shmId, 0, 0);
+#else
+    QByteArray shmName = makeKey(shmId);
+    EINTR_LOOP(hand, shm_open(shmName.constData(), O_RDWR, 0660));
+    if (hand != -1) {
+        // grab the size
+        QT_STATBUF st;
+        if (QT_FSTAT(hand, &st) != -1) {
+            shmSize = st.st_size;
+            // grab the memory
+            shmBase = mmap(0, shmSize, PROT_READ | PROT_WRITE, MAP_SHARED, hand, 0);
+        }
+    }
+#endif
     if (shmBase == (void*)-1 || !shmBase) {
 #ifdef QT_SHM_DEBUG
         perror("QWSSharedMemory::attach():");
@@ -117,8 +182,28 @@ bool QWSSharedMemory::attach(int id)
 
 void QWSSharedMemory::detach()
 {
+#ifndef QT_POSIX_IPC
     if (shmBase && shmBase != (void*)-1)
         shmdt(shmBase);
+#else
+    if (shmBase && shmBase != (void*)-1)
+        munmap(shmBase, shmSize);
+    if (hand > 0) {
+        // get the number of current attachments
+        int shm_nattch = 0;
+        QT_STATBUF st;
+        if (QT_FSTAT(hand, &st) == 0) {
+            // subtract 2 from linkcount: one for our own open and one for the dir entry
+            shm_nattch = st.st_nlink - 2;
+        }
+        qt_safe_close(hand);
+        // if there are no attachments then unlink the shared memory
+        if (shm_nattch == 0) {
+            QByteArray shmName = makeKey(shmId);
+            shm_unlink(shmName.constData());
+        }
+    }
+#endif
     shmBase = 0;
     shmSize = 0;
     shmId = -1;
@@ -129,11 +214,13 @@ int QWSSharedMemory::size() const
     if (shmId == -1)
         return 0;
 
+#ifndef QT_POSIX_IPC
     if (!shmSize) {
         struct shmid_ds shm;
         shmctl(shmId, IPC_STAT, &shm);
-        const_cast<QWSSharedMemory *>(this)->shmSize = shm.shm_segsz;
+        shmSize = shm.shm_segsz;
     }
+#endif
 
     return shmSize;
 }
diff --git a/src/gui/embedded/qwssharedmemory_p.h b/src/gui/embedded/qwssharedmemory_p.h
index f3ce24101b..42ef6c8cef 100644
--- a/src/gui/embedded/qwssharedmemory_p.h
+++ b/src/gui/embedded/qwssharedmemory_p.h
@@ -77,7 +77,10 @@ public:
 private:
     int shmId;
     void *shmBase;
-    int shmSize;
+    mutable int shmSize;
+#ifdef QT_POSIX_IPC
+    int hand;
+#endif
 };
 
 #endif // QT_NO_QWS_MULTIPROCESS
diff --git a/src/gui/painting/qwindowsurface_qws.cpp b/src/gui/painting/qwindowsurface_qws.cpp
index 7e8cf9bbb1..3789a33110 100644
--- a/src/gui/painting/qwindowsurface_qws.cpp
+++ b/src/gui/painting/qwindowsurface_qws.cpp
@@ -1065,10 +1065,12 @@ bool QWSSharedMemSurface::setMemory(int memId)
         return true;
 
     mem.detach();
-    if (!mem.attach(memId)) {
+
+    if (memId != -1 && !mem.attach(memId)) {
+#ifndef QT_NO_DEBUG
         perror("QWSSharedMemSurface: attaching to shared memory");
-        qCritical("QWSSharedMemSurface: Error attaching to"
-                  " shared memory 0x%x", memId);
+        qCritical("QWSSharedMemSurface: Error attaching to shared memory 0x%x", memId);
+#endif
         return false;
     }
 
diff --git a/src/gui/text/qfontdatabase_qws.cpp b/src/gui/text/qfontdatabase_qws.cpp
index c5a04f1700..87862e7183 100644
--- a/src/gui/text/qfontdatabase_qws.cpp
+++ b/src/gui/text/qfontdatabase_qws.cpp
@@ -75,6 +75,11 @@
 #include <qresource.h>
 #endif
 
+#ifdef Q_OS_QNX
+// ### using QFontEngineQPF leads to artifacts on QNX
+#  define QT_NO_QWS_SHARE_FONTS
+#endif
+
 QT_BEGIN_NAMESPACE
 
 #ifndef QT_NO_LIBRARY