aboutsummaryrefslogtreecommitdiffstats
path: root/linux-user/uaccess.c
diff options
context:
space:
mode:
Diffstat (limited to 'linux-user/uaccess.c')
-rw-r--r--linux-user/uaccess.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/linux-user/uaccess.c b/linux-user/uaccess.c
new file mode 100644
index 00000000..a4d108c2
--- /dev/null
+++ b/linux-user/uaccess.c
@@ -0,0 +1,65 @@
+/* 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;
+}
+
+/* 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((const char *)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;
+}