[Qemu-devel] [5959] linux-user: mremap(): handle MREMAP_FIXED and MREMAP_MAYMOVE correctly

[Qemu-devel] [5959] linux-user: mremap(): handle MREMAP_FIXED and MREMAP_MAYMOVE correctly

[Aurelien Jarno]

Revision: 5959
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5959
Author:   aurel32
Date:     2008-12-08 18:12:40 +0000 (Mon, 08 Dec 2008)

Log Message:
-----------
linux-user: mremap(): handle MREMAP_FIXED and MREMAP_MAYMOVE correctly

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

Modified Paths:
--------------
    trunk/linux-user/mmap.c

Modified: trunk/linux-user/mmap.c
===================================================================
--- trunk/linux-user/mmap.c	2008-12-08 18:12:33 UTC (rev 5958)
+++ trunk/linux-user/mmap.c	2008-12-08 18:12:40 UTC (rev 5959)
@@ -537,19 +537,41 @@
     return ret;
 }
 
-/* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
-   blocks which have been allocated starting on a host page */
 abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
                        abi_ulong new_size, unsigned long flags,
                        abi_ulong new_addr)
 {
     int prot;
-    unsigned long host_addr;
+    void *host_addr;
 
     mmap_lock();
-    /* XXX: use 5 args syscall */
-    host_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags);
-    if (host_addr == -1) {
+
+    if (flags & MREMAP_FIXED)
+        host_addr = mremap(g2h(old_addr), old_size, new_size,
+                           flags, new_addr);
+    else if (flags & MREMAP_MAYMOVE) {
+        abi_ulong mmap_start;
+
+        mmap_start = mmap_find_vma(0, new_size);
+
+        if (mmap_start == -1) {
+            errno = ENOMEM;
+            host_addr = MAP_FAILED;
+        } else
+            host_addr = mremap(g2h(old_addr), old_size, new_size,
+                               flags | MREMAP_FIXED, g2h(mmap_start));
+    } else {
+        host_addr = mremap(g2h(old_addr), old_size, new_size, flags);
+        /* Check if address fits target address space */
+        if ((unsigned long)host_addr + new_size > (abi_ulong)-1) {
+            /* Revert mremap() changes */
+            host_addr = mremap(g2h(old_addr), new_size, old_size, flags);
+            errno = ENOMEM;
+            host_addr = MAP_FAILED;
+        }
+    }
+
+    if (host_addr == MAP_FAILED) {
         new_addr = -1;
     } else {
         new_addr = h2g(host_addr);