1 files changed, 88 insertions, 1 deletions

diff --git a/src/gui/embedded/qwssharedmemory.cpp b/src/gui/embedded/qwssharedmemory.cpp
index a677626..853de61 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;
 }