Fixes in "new" mmap

* mem.c (sys_mmap): Ensure unsigned expansion of tcp->u_arg[5].
Add page shift of offset for I386.
Use tcp->ext_arg[5] as offset for X32.
(sys_old_mmap): [X32] Remove this function, X32 doesn't use is.

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

diff --git a/mem.c b/mem.c
index a0cfc523a72d8157609b8c9c8e213c1c919c8fc5..389e098c52fd207304b677a40e81ce9f40595113 100644 (file)
--- a/mem.c
+++ b/mem.c
@@ -280,13 +280,8 @@ int sys_old_mmap(struct tcb *tcp)
 int
 sys_mmap(struct tcb *tcp)
 {
-       long long offset = tcp->u_arg[5];
+       unsigned long long offset = (unsigned long) tcp->u_arg[5];
 
-       /* FIXME: why only SH64? i386 mmap2 syscall ends up
-        * in this function, but does not convert offset
-        * from pages to bytes. See test/mmap_offset_decode.c
-        * Why SH64 and i386 are handled differently?
-        */
 #if defined(SH64)
        /*
         * Old mmap differs from new mmap in specifying the
@@ -295,8 +290,12 @@ sys_mmap(struct tcb *tcp)
         * sees bytes in the printout.
         */
        offset <<= PAGE_SHIFT;
-#endif
-#if defined(LINUX_MIPSN32)
+#elif defined(I386)
+       /* Try test/mmap_offset_decode.c */
+       offset <<= 12; /* 4096 byte pages */
+#elif defined(LINUX_MIPSN32) || defined(X32)
+       /* Try test/x32_mmap.c */
+       /* At least for X32 it definitely should not be page-shifted! */
        offset = tcp->ext_arg[5];
 #endif
        return print_mmap(tcp, tcp->u_arg, offset);
@@ -304,40 +303,6 @@ sys_mmap(struct tcb *tcp)
 #endif /* !HAVE_LONG_LONG_OFF_T */
 
 #if _LFS64_LARGEFILE || HAVE_LONG_LONG_OFF_T
-# if defined(X32)
-int sys_old_mmap(struct tcb *tcp)
-{
-       long u_arg[6];
-       if (umoven(tcp, tcp->u_arg[0], sizeof(u_arg), (char *) u_arg) == -1)
-               return 0;
-       if (entering(tcp)) {
-               /* addr */
-               if (!u_arg[0])
-                       tprints("NULL, ");
-               else
-                       tprintf("%#lx, ", u_arg[0]);
-               /* len */
-               tprintf("%lu, ", u_arg[1]);
-               /* prot */
-               printflags(mmap_prot, u_arg[2], "PROT_???");
-               tprints(", ");
-               /* flags */
-#  ifdef MAP_TYPE
-               printxval(mmap_flags, u_arg[3] & MAP_TYPE, "MAP_???");
-               addflags(mmap_flags, u_arg[3] & ~MAP_TYPE);
-#  else
-               printflags(mmap_flags, u_arg[3], "MAP_???");
-#  endif
-               /* fd */
-               tprints(", ");
-               printfd(tcp, u_arg[4]);
-               /* offset */
-               tprintf(", %#lx", u_arg[5]);
-       }
-       return RVAL_HEX;
-}
-# endif
-
 /* TODO: comment which arches use this routine.
  * For one, does ALPHA on Linux use this??
  * From code it seems that it might use 7 or 8 registers,

diff --git a/test/x32_mmap.c b/test/x32_mmap.c
new file mode 100644 (file)
index 0000000..cbef36d
--- /dev/null
+++ b/test/x32_mmap.c
@@ -0,0 +1,49 @@
+// Test program which explores whether mmap's ofs parameter
+// is 64-bit, and whether it needs to be shifted << PAGE_SHIFT.
+// Apparently it is 64-bit and isn't shifted.
+//
+// Build: x86_64-gcc -static -Wall -ox32_mmap x32_mmap.c
+// Typical output:
+// 7f9390696000-7f93906a6000 r--s 12345670000 08:06 2224545 /etc/passwd
+//                                ^^^^^^^^^^^
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+// Ensure we are compiling to 64 bits
+struct bug { int t[sizeof(long) > 4 ? 1 : -1]; };
+int main(int argc, char **argv)
+{
+       long ofs = 0x12345670000; // fails if not page-aligned
+       errno = 0;
+       close(0);
+       if (open("/etc/passwd", O_RDONLY))
+               return 1;
+       long r = syscall(
+               (long) (__NR_mmap | 0x40000000), // make x32 call
+               (long) (0),             // start
+               (long) (0x10000),       // len
+               (long) (PROT_READ),     // prot
+               (long) (MAP_SHARED),    // flags
+               (long) (0),             // fd
+               (long) (ofs)            // ofs
+       );
+       printf("ret:0x%lx errno:%m\n", r);
+
+       char buf[16*1024];
+       sprintf(buf, "/proc/%d/maps", getpid());
+       int fd = open(buf, O_RDONLY);
+       if (fd > 0) {
+               int sz = read(fd, buf, sizeof(buf));
+               if (sz > 0)
+                       write(1, buf, sz);
+       }
+
+       return 0;
+}