Re: [Qemu-devel] [PATCH] Fix building with glibc < 2.4

[Robert Reif]

Kirill A. Shutemov wrote:
> Prior to version 2.4, glibc did not expose the definition of
> MREMAP_FIXED, and the prototype for mremap() did not allow
> for the new_address argument.
>
> Tested only with glibc 2.9.
>
> Signed-off-by: Kirill A. Shutemov <address@hidden>
> ---
>  linux-user/mmap.c |   10 +++++++---
>  1 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> index 89254ae..b6dd184 100644
> --- a/linux-user/mmap.c
> +++ b/linux-user/mmap.c
> @@ -24,6 +24,8 @@
>  #include <unistd.h>
>  #include <errno.h>
>  #include <sys/mman.h>
> +#include <linux/mman.h>
> +#include <linux/unistd.h>
>  
>  #include "qemu.h"
>  #include "qemu-common.h"
> @@ -564,9 +566,11 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong 
> old_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 = (void *) syscall(__NR_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 */
>   
This version compiles for me.

Index: linux-user/mmap.c
===================================================================
--- linux-user/mmap.c   (revision 5961)
+++ linux-user/mmap.c   (working copy)
@@ -24,6 +24,8 @@
 #include <unistd.h>
 #include <errno.h>
 #include <sys/mman.h>
+#include <linux/mman.h>
+#include <linux/unistd.h>
 
 #include "qemu.h"
 #include "qemu-common.h"
@@ -547,8 +549,8 @@
     mmap_lock();
 
     if (flags & MREMAP_FIXED)
-        host_addr = mremap(g2h(old_addr), old_size, new_size,
-                           flags, new_addr);
+        host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
+                           old_size, new_size, flags, new_addr);
     else if (flags & MREMAP_MAYMOVE) {
         abi_ulong mmap_start;
 
@@ -557,9 +559,11 @@
         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 = (void *) syscall(__NR_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 */