[Qemu-devel] Re: [kvm-devel] [PATCH] Making SLIRP code more 64-bit clean

[Scott Pakin]

Zhang, Xiantao wrote:
> Scott Pakin wrote:
> > The attached patch corrects a bug in qemu/slirp/tcp_var.h that defines
> > the seg_next field in struct tcpcb to be 32 bits wide regardless of
> > 32/64-bitness.  seg_next is assigned a pointer value in
> > qemu/slirp/tcp_subr.c, then cast back to a pointer in
> > qemu/slirp/tcp_input.c and dereferenced.  That produces a SIGSEGV on
> > my system. 
>
>
> I still hit it on IA64 platform with your patch, once configured with
> slirp.  

Okay, here's a more thorough patch that fixes *all* of the "cast from/to
pointer to/from integer of a different size" mistakes that gcc warns
about.  Does it also solve the SIGSEGV problem on IA64?

-- Scott

================== BEGIN tcp_int32_pointer_cast.patch ==================
diff -Naur kvm-60-ORIG/qemu/exec-all.h kvm-60/qemu/exec-all.h
--- kvm-60-ORIG/qemu/exec-all.h 2008-01-20 05:35:04.000000000 -0700
+++ kvm-60/qemu/exec-all.h      2008-01-29 19:19:45.000000000 -0700
@@ -169,7 +169,7 @@
 #ifdef USE_DIRECT_JUMP
     uint16_t tb_jmp_offset[4]; /* offset of jump instruction */
 #else
-    uint32_t tb_next[2]; /* address of jump generated code */
+    uintptr_t tb_next[2]; /* address of jump generated code */
 #endif
     /* list of TBs jumping to this one. This is a circular list using
        the two least significant bits of the pointers to tell what is
diff -Naur kvm-60-ORIG/qemu/slirp/ip.h kvm-60/qemu/slirp/ip.h
--- kvm-60-ORIG/qemu/slirp/ip.h 2008-01-20 05:35:04.000000000 -0700
+++ kvm-60/qemu/slirp/ip.h      2008-01-29 19:13:09.000000000 -0700
@@ -183,23 +183,9 @@

 #define        IP_MSS          576             /* default maximum segment size 
*/

-#ifdef HAVE_SYS_TYPES32_H  /* Overcome some Solaris 2.x junk */
-#include <sys/types32.h>
-#else
-#if SIZEOF_CHAR_P == 4
 typedef caddr_t caddr32_t;
-#else
-typedef u_int32_t caddr32_t;
-#endif
-#endif
-
-#if SIZEOF_CHAR_P == 4
 typedef struct ipq *ipqp_32;
 typedef struct ipasfrag *ipasfragp_32;
-#else
-typedef caddr32_t ipqp_32;
-typedef caddr32_t ipasfragp_32;
-#endif

 /*
  * Overlay for ip header used by other protocols (tcp, udp).
diff -Naur kvm-60-ORIG/qemu/slirp/misc.c kvm-60/qemu/slirp/misc.c
--- kvm-60-ORIG/qemu/slirp/misc.c       2008-01-20 05:35:04.000000000 -0700
+++ kvm-60/qemu/slirp/misc.c    2008-01-29 11:36:15.000000000 -0700
@@ -97,39 +97,6 @@
             our_addr.s_addr = loopback_addr.s_addr;
 }

-#if SIZEOF_CHAR_P == 8
-
-struct quehead_32 {
-       u_int32_t qh_link;
-       u_int32_t qh_rlink;
-};
-
-inline void
-insque_32(a, b)
-       void *a;
-       void *b;
-{
-       register struct quehead_32 *element = (struct quehead_32 *) a;
-       register struct quehead_32 *head = (struct quehead_32 *) b;
-       element->qh_link = head->qh_link;
-       head->qh_link = (u_int32_t)element;
-       element->qh_rlink = (u_int32_t)head;
-       ((struct quehead_32 *)(element->qh_link))->qh_rlink
-       = (u_int32_t)element;
-}
-
-inline void
-remque_32(a)
-       void *a;
-{
-       register struct quehead_32 *element = (struct quehead_32 *) a;
-       ((struct quehead_32 *)(element->qh_link))->qh_rlink = element->qh_rlink;
-       ((struct quehead_32 *)(element->qh_rlink))->qh_link = element->qh_link;
-       element->qh_rlink = 0;
-}
-
-#endif /* SIZEOF_CHAR_P == 8 */
-
 struct quehead {
        struct quehead *qh_link;
        struct quehead *qh_rlink;
diff -Naur kvm-60-ORIG/qemu/slirp/slirp.h kvm-60/qemu/slirp/slirp.h
--- kvm-60-ORIG/qemu/slirp/slirp.h      2008-01-20 05:35:04.000000000 -0700
+++ kvm-60/qemu/slirp/slirp.h   2008-01-29 11:37:19.000000000 -0700
@@ -265,13 +265,8 @@

 void lprint _P((const char *, ...));

-#if SIZEOF_CHAR_P == 4
-# define insque_32 insque
-# define remque_32 remque
-#else
- inline void insque_32 _P((void *, void *));
- inline void remque_32 _P((void *));
-#endif
+#define insque_32 insque
+#define remque_32 remque

 #ifndef _WIN32
 #include <netdb.h>
diff -Naur kvm-60-ORIG/qemu/slirp/tcp_var.h kvm-60/qemu/slirp/tcp_var.h
--- kvm-60-ORIG/qemu/slirp/tcp_var.h    2008-01-20 05:35:04.000000000 -0700
+++ kvm-60/qemu/slirp/tcp_var.h 2008-01-28 21:12:22.000000000 -0700
@@ -40,11 +40,7 @@
 #include "tcpip.h"
 #include "tcp_timer.h"

-#if SIZEOF_CHAR_P == 4
- typedef struct tcpiphdr *tcpiphdrp_32;
-#else
- typedef u_int32_t tcpiphdrp_32;
-#endif
+typedef struct tcpiphdr *tcpiphdrp_32;

 /*
  * Tcp control block, one per tcp; fields:
@@ -178,11 +174,7 @@
  * port numbers (which are no longer needed once we've located the
  * tcpcb) are overlayed with an mbuf pointer.
  */
-#if SIZEOF_CHAR_P == 4
 typedef struct mbuf *mbufp_32;
-#else
-typedef u_int32_t mbufp_32;
-#endif
 #define REASS_MBUF(ti) (*(mbufp_32 *)&((ti)->ti_t))

 #ifdef LOG_ENABLED
=================== END tcp_int32_pointer_cast.patch ===================