Preliminary BSD user emulator support

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5544 c046a42c-6fe2-441c-8c8c-71466251a162

bsd-user/uaccess.c

@@ -0,0 +1,76 @@
+/* User memory access */
+#include <stdio.h>
+#include <string.h>
+
+#include "qemu.h"
+
+/* copy_from_user() and copy_to_user() are usually used to copy data
+ * buffers between the target and host.  These internally perform
+ * locking/unlocking of the memory.
+ */
+abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len)
+{
+    abi_long ret = 0;
+    void *ghptr;
+
+    if ((ghptr = lock_user(VERIFY_READ, gaddr, len, 1))) {
+        memcpy(hptr, ghptr, len);
+        unlock_user(ghptr, gaddr, 0);
+    } else
+        ret = -TARGET_EFAULT;
+
+    return ret;
+}
+
+
+abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
+{
+    abi_long ret = 0;
+    void *ghptr;
+
+    if ((ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0))) {
+        memcpy(ghptr, hptr, len);
+        unlock_user(ghptr, gaddr, len);
+    } else
+        ret = -TARGET_EFAULT;
+
+    return ret;
+}
+
+/* XXX: use host strnlen if available ? */
+static int qemu_strnlen(const char *s, int max_len)
+{
+    int i;
+    for(i = 0; i < max_len; i++) {
+        if (s[i] == '\0')
+            break;
+    }
+    return i;
+}
+
+/* Return the length of a string in target memory or -TARGET_EFAULT if
+   access error  */
+abi_long target_strlen(abi_ulong guest_addr1)
+{
+    uint8_t *ptr;
+    abi_ulong guest_addr;
+    int max_len, len;
+
+    guest_addr = guest_addr1;
+    for(;;) {
+        max_len = TARGET_PAGE_SIZE - (guest_addr & ~TARGET_PAGE_MASK);
+        ptr = lock_user(VERIFY_READ, guest_addr, max_len, 1);
+        if (!ptr)
+            return -TARGET_EFAULT;
+        len = qemu_strnlen(ptr, max_len);
+        unlock_user(ptr, guest_addr, 0);
+        guest_addr += len;
+        /* we don't allow wrapping or integer overflow */
+        if (guest_addr == 0 ||
+            (guest_addr - guest_addr1) > 0x7fffffff)
+            return -TARGET_EFAULT;
+        if (len != max_len)
+            break;
+    }
+    return guest_addr - guest_addr1;
+}