Changeset 3596 in vbox for trunk/src

Timestamp:

Jul 12, 2007 6:42:03 PM (18 years ago)

Author:

vboxsync

Message:

fixed error detection in mmap()

File:

• trunk/src/VBox/HostDrivers/Support/linux/SUPLib-linux.cpp (modified) (2 diffs)

trunk/src/VBox/HostDrivers/Support/linux/SUPLib-linux.cpp

@@ -131 +131 @@
      */
     void *pv = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-    if (!pv)
+    if (pv == MAP_FAILED)
         return VERR_NO_MEMORY;
     g_fSysMadviseWorks = (0 == madvise(pv, PAGE_SIZE, MADV_DONTFORK));
@@ -253 +253 @@
 int     suplibOsPageAlloc(size_t cPages, void **ppvPages)
 {
-#if 0
-    int rc = posix_memalign(ppvPages, PAGE_SIZE, cPages << PAGE_SHIFT)
-    if (!rc)
-    {
-        memset(*ppvPages, 0, cPages << PAGE_SHIFT);
-        return VINF_SUCCESS;
-    }
-    return RTErrConvertFromErrno(rc);
-#else
     size_t cbMmap = (g_fSysMadviseWorks ? cPages : cPages + 2) << PAGE_SHIFT;
     char *pvPages = (char *)mmap(NULL, cbMmap, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-    if (pvPages)
-    {
-        if (g_fSysMadviseWorks)
-        {
-            /*
-             * It is not fatal if we fail here but a forked child (e.g. the ALSA sound server)
-             * could crash. Linux < 2.6.16 does not implement madvise(MADV_DONTFORK) but the
-             * kernel seems to split bigger VMAs and that is all that we want -- later we set the
-             * VM_DONTCOPY attribute in supdrvOSLockMemOne().
-             */
-            if (madvise (pvPages, cbMmap, MADV_DONTFORK))
-                LogRel(("SUPLib: madvise %p-%p failed\n", pvPages, cbMmap));
-            *ppvPages = pvPages;
-        }
-        else
-        {
-            /*
-             * madvise(MADV_DONTFORK) is not available (most probably Linux 2.4). Enclose any
-             * mmapped region by two unmapped pages to guarantee that there is exactly one VM
-             * area struct of the very same size as the mmap area.
-             */
-            mprotect(pvPages,                      PAGE_SIZE, PROT_NONE);
-            mprotect(pvPages + cbMmap - PAGE_SIZE, PAGE_SIZE, PROT_NONE);
-            *ppvPages = pvPages + PAGE_SIZE;
-        }
-        memset(*ppvPages, 0, cPages << PAGE_SHIFT);
-        return VINF_SUCCESS;
-    }
-    return VERR_NO_MEMORY;
-#endif
+    if (pvPages == MAP_FAILED)
+        return VERR_NO_MEMORY;
+
+    if (g_fSysMadviseWorks)
+    {
+        /*
+         * It is not fatal if we fail here but a forked child (e.g. the ALSA sound server)
+         * could crash. Linux < 2.6.16 does not implement madvise(MADV_DONTFORK) but the
+         * kernel seems to split bigger VMAs and that is all that we want -- later we set the
+         * VM_DONTCOPY attribute in supdrvOSLockMemOne().
+         */
+        if (madvise (pvPages, cbMmap, MADV_DONTFORK))
+            LogRel(("SUPLib: madvise %p-%p failed\n", pvPages, cbMmap));
+        *ppvPages = pvPages;
+    }
+    else
+    {
+        /*
+         * madvise(MADV_DONTFORK) is not available (most probably Linux 2.4). Enclose any
+         * mmapped region by two unmapped pages to guarantee that there is exactly one VM
+         * area struct of the very same size as the mmap area.
+         */
+        mprotect(pvPages,                      PAGE_SIZE, PROT_NONE);
+        mprotect(pvPages + cbMmap - PAGE_SIZE, PAGE_SIZE, PROT_NONE);
+        *ppvPages = pvPages + PAGE_SIZE;
+    }
+    memset(*ppvPages, 0, cPages << PAGE_SHIFT);
+    return VINF_SUCCESS;
 }