flashplugin-lahf-fix/flashplugin-lahf-fix.c

   1 /* Simple work-around for running the 64-bit Adobe Flash plug-in version 10
   2    on Athlon64 processors without support for the lahf instruction.
   3
   4 Compile with:
   5 cc -fPIC -shared -nostdlib -lc -oflashplugin-lahf-fix.so flashplugin-lahf-fix.c
   6 Then place the .so file in the plug-in directory (e.g. $HOME/.mozilla/plugins)
   7 or use LD_PRELOAD to force Firefox to load the library.
   8
   9    - Maks Verver <maksverver@geocities.com> July 2009 */
  10
  11 #define _GNU_SOURCE
  12 #include <stdlib.h>
  13 #include <signal.h>
  14 #include <ucontext.h>
  15
  16 static void sig_handler(int signal, siginfo_t *info, void *context) {
  17         if (signal != SIGILL) return;
  18         if (*(char*)info->si_addr != (char)0x9f) abort();
  19         greg_t *regs = ((ucontext_t*)context)->uc_mcontext.gregs;
  20         ((char*)&regs[REG_RAX])[1] = ((char*)&regs[REG_EFL])[0];
  21         regs[REG_RIP]++;
  22 }
  23
  24 static struct sigaction old_sa, new_sa = {
  25         .sa_flags     = SA_SIGINFO,
  26         .sa_sigaction = &sig_handler };
  27
  28 int _init() { sigaction(SIGILL, &new_sa, &old_sa); return 0; }
  29 int _fini() { sigaction(SIGILL, &old_sa, &new_sa); return 0; }