event_notifier: prevent accidental use after close

[mirror_qemu.git] / util / mmap-alloc.c

diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index d713a72ddcf503e7e5cbda14d9bf5b585a11ad52..3ec029a9eaebccf70da0047693a179e6f9be905d 100644 (file)
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -40,6 +40,31 @@ size_t qemu_fd_getpagesize(int fd)
     return getpagesize();
 }
 
+size_t qemu_mempath_getpagesize(const char *mem_path)
+{
+#ifdef CONFIG_LINUX
+    struct statfs fs;
+    int ret;
+
+    do {
+        ret = statfs(mem_path, &fs);
+    } while (ret != 0 && errno == EINTR);
+
+    if (ret != 0) {
+        fprintf(stderr, "Couldn't statfs() memory path: %s\n",
+                strerror(errno));
+        exit(1);
+    }
+
+    if (fs.f_type == HUGETLBFS_MAGIC) {
+        /* It's hugepage, return the huge page size */
+        return fs.f_bsize;
+    }
+#endif
+
+    return getpagesize();
+}
+
 void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared)
 {
     /*
@@ -84,22 +109,20 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared)
         return MAP_FAILED;
     }
 
-    ptr += offset;
-    total -= offset;
-
     if (offset > 0) {
-        munmap(ptr - offset, offset);
+        munmap(ptr, offset);
     }
 
     /*
      * Leave a single PROT_NONE page allocated after the RAM block, to serve as
      * a guard page guarding against potential buffer overflows.
      */
+    total -= offset;
     if (total > size + getpagesize()) {
-        munmap(ptr + size + getpagesize(), total - size - getpagesize());
+        munmap(ptr1 + size + getpagesize(), total - size - getpagesize());
     }
 
-    return ptr;
+    return ptr1;
 }
 
 void qemu_ram_munmap(void *ptr, size_t size)