[Qemu-devel] [PATCH 13/20] oslib: add a wrapper for mmap/munmap

[Paolo Bonzini <pbonzini@redhat.com>]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 osdep.h       | 10 ++++++++++
 oslib-posix.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 oslib-win32.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+)

diff --git a/osdep.h b/osdep.h
index 87d3b9c..fb7f72c 100644
--- a/osdep.h
+++ b/osdep.h
@@ -134,6 +134,16 @@ void qemu_vfree(void *ptr);
 
 #endif
 
+typedef struct QEMUMmapArea {
+    int fd;
+    void *mem;
+    size_t size;
+} QEMUMmapArea;
+
+int qemu_mmap_alloc(QEMUMmapArea *mm, const char *path, size_t size);
+int qemu_mmap_flush(QEMUMmapArea *mm);
+void qemu_mmap_free(QEMUMmapArea *mm);
+
 int qemu_madvise(void *addr, size_t len, int advice);
 
 int qemu_open(const char *name, int flags, ...);
diff --git a/oslib-posix.c b/oslib-posix.c
index 9db9c3d..f230f61 100644
--- a/oslib-posix.c
+++ b/oslib-posix.c
@@ -61,6 +61,7 @@ static int running_on_valgrind = -1;
 #ifdef CONFIG_LINUX
 #include <sys/syscall.h>
 #endif
+#include <sys/mman.h>
 
 int qemu_get_thread_id(void)
 {
@@ -226,3 +227,49 @@ int qemu_utimens(const char *path, const struct timespec *times)
 
     return utimes(path, &tv[0]);
 }
+
+int qemu_mmap_alloc(QEMUMmapArea *mm, const char *path, size_t size)
+{
+    int fd = -1;
+    char *mem = NULL;
+    int save_errno;
+
+    fd = qemu_open(path, O_RDWR | O_CREAT, 0666);
+    if (fd < 0) {
+        goto fail;
+    }
+
+    if (ftruncate(fd, size) < 0) {
+        goto fail;
+    }
+
+    mem = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+    if (!mem) {
+        goto fail;
+    }
+
+    mm->fd = fd;
+    mm->mem = mem;
+    mm->size = size;
+    return 0;
+
+fail:
+    save_errno = errno;
+    if (fd >= 0) {
+        close(fd);
+        unlink(path);
+    }
+    return -save_errno;
+}
+
+int qemu_mmap_flush(QEMUMmapArea *mm)
+{
+    int rc = msync(mm->mem, mm->size, MS_SYNC);
+    return rc < 0 ? -errno : 0;
+}
+
+void qemu_mmap_free(QEMUMmapArea *mm)
+{
+    munmap(mm->mem, mm->size);
+    close(mm->fd);
+}
diff --git a/oslib-win32.c b/oslib-win32.c
index 51b33e8..3885a31 100644
--- a/oslib-win32.c
+++ b/oslib-win32.c
@@ -150,3 +150,62 @@ int qemu_get_thread_id(void)
 {
     return GetCurrentThreadId();
 }
+
+int qemu_mmap_alloc(QEMUMmapArea *mm, const char *path, size_t size)
+{
+    int fd = -1;
+    char *mem = NULL;
+
+    HANDLE hFile, hMapping;
+    int save_errno;
+
+    fd = qemu_open(path, O_RDWR | O_CREAT, 0666);
+    if (fd < 0) {
+        goto fail;
+    }
+
+    hFile = (HANDLE)_get_osfhandle(fd);
+    if (ftruncate(fd, size) < 0) {
+        goto fail;
+    }
+
+    hMapping = CreateFileMapping(hFile, NULL, PAGE_EXECUTE_READWRITE,
+                                 0, 0, NULL);
+    if (!hMapping) {
+        goto fail;
+    }
+
+    mem = MapViewOfFileEx(hMapping, FILE_MAP_WRITE, 0, 0, size, NULL);
+    CloseHandle(hMapping);
+    if (mem) {
+        goto fail;
+    }
+
+    mm->fd = fd;
+    mm->mem = mem;
+    mm->size = size;
+    return 0;
+
+fail:
+    save_errno = errno;
+    if (fd >= 0) {
+        close(fd);
+        unlink(path);
+    }
+    return -save_errno;
+}
+
+int qemu_mmap_flush(QEMUMmapArea *mm)
+{
+    int rc;
+
+    FlushViewOfFile(mm->mem, mm->size);
+    rc = qemu_fdatasync(mm->fd);
+    return rc < 0 ? -errno : 0;
+}
+
+void qemu_mmap_free(QEMUMmapArea *mm)
+{
+    UnmapViewOfFile(mm->mem);
+    close(mm->fd);
+}
-- 
1.8.0.1