Preliminary simplifications in mmap functions

* mem.c: Move "define sys_mmap64 sys_mmap" from the top
to the only place it affects.
(print_mmap): Make offset argument unsigned, for safer implicit conversions.
(sys_old_mmap): [IA64] use unsigned narrow_arg[].
Cast u_arg[5] (offset param) to unsigned long, to prevent erroneous signed
expansion.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/mem.c b/mem.c
index deefff3d79f8760387a36fea5a4a245fc871552e..a0cfc523a72d8157609b8c9c8e213c1c919c8fc5 100644 (file)
--- a/mem.c
+++ b/mem.c
@@ -43,13 +43,6 @@
 # include <asm/page.h>     /* for PAGE_SHIFT */
 #endif
 
-#ifdef HAVE_LONG_LONG_OFF_T
-/*
- * Ugly hacks for systems that have a long long off_t
- */
-# define sys_mmap64    sys_mmap
-#endif
-
 int
 sys_brk(struct tcb *tcp)
 {
@@ -211,7 +204,7 @@ addtileflags(long flags)
 
 #if !HAVE_LONG_LONG_OFF_T
 static int
-print_mmap(struct tcb *tcp, long *u_arg, long long offset)
+print_mmap(struct tcb *tcp, long *u_arg, unsigned long long offset)
 {
        if (entering(tcp)) {
                /* addr */
@@ -227,16 +220,16 @@ print_mmap(struct tcb *tcp, long *u_arg, long long offset)
                /* flags */
 #ifdef MAP_TYPE
                printxval(mmap_flags, u_arg[3] & MAP_TYPE, "MAP_???");
-#ifdef TILE
+# ifdef TILE
                addflags(mmap_flags, addtileflags(u_arg[3] & ~MAP_TYPE));
-#else
+# else
                addflags(mmap_flags, u_arg[3] & ~MAP_TYPE);
-#endif
+# endif
 #else
                printflags(mmap_flags, u_arg[3], "MAP_???");
 #endif
-               /* fd */
                tprints(", ");
+               /* fd */
                printfd(tcp, u_arg[4]);
                /* offset */
                tprintf(", %#llx", offset);
@@ -252,14 +245,10 @@ int sys_old_mmap(struct tcb *tcp)
         * new `sys_mmap' interface.
         * For IA32 processes, this code converts the integer arguments
         * that they pushed onto the stack, into longs.
-        *
-        * Note that addresses with bit 31 set will be sign extended.
-        * Fortunately, those addresses are not currently being generated
-        * for IA32 processes so it's not a problem.
         */
        int i;
        long u_arg[6];
-       int narrow_arg[6];
+       unsigned narrow_arg[6];
        if (umoven(tcp, tcp->u_arg[0], sizeof(narrow_arg), (char *) narrow_arg) == -1)
                return 0;
        for (i = 0; i < 6; i++)
@@ -267,9 +256,8 @@ int sys_old_mmap(struct tcb *tcp)
 #elif defined(SH) || defined(SH64)
        /* SH has always passed the args in registers */
        long *u_arg = tcp->u_arg;
-#else
+#elif defined(X86_64)
        long u_arg[6];
-# if defined(X86_64)
        if (current_personality == 1) {
                int i;
                unsigned narrow_arg[6];
@@ -277,14 +265,16 @@ int sys_old_mmap(struct tcb *tcp)
                        return 0;
                for (i = 0; i < 6; ++i)
                        u_arg[i] = narrow_arg[i];
+       } else {
+               if (umoven(tcp, tcp->u_arg[0], sizeof(u_arg), (char *) u_arg) == -1)
+                       return 0;
        }
-       else
-# endif
+#else
+       long u_arg[6];
        if (umoven(tcp, tcp->u_arg[0], sizeof(u_arg), (char *) u_arg) == -1)
                return 0;
-#endif /* other architectures */
-
-       return print_mmap(tcp, u_arg, u_arg[5]);
+#endif
+       return print_mmap(tcp, u_arg, (unsigned long)u_arg[5]);
 }
 
 int
@@ -353,6 +343,12 @@ int sys_old_mmap(struct tcb *tcp)
  * From code it seems that it might use 7 or 8 registers,
  * which is strange - Linux syscalls can pass maximum of 6 parameters!
  */
+# ifdef HAVE_LONG_LONG_OFF_T
+/* For systems that have a long long off_t,
+ * sys_mmap in syscall tables is handled by sys_mmap64:
+ */
+#  define sys_mmap64 sys_mmap
+# endif
 int
 sys_mmap64(struct tcb *tcp)
 {