commands/mdb/syscalls.c

   1 /*
   2  * syscall.c for mdb
   3  */
   4 #include "mdb.h"
   5 #ifdef SYSCALLS_SUPPORT
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <sys/ptrace.h>
   9 #include "proto.h"
  10
  11 #define SYSCALL_NAME    "__sendrec"
  12 #ifdef __i386
  13 #define SYSCALL_OFFSET  0xF
  14 #define SYSCALL_OLD     0x21CD
  15 #else
  16 #define SYSCALL_OFFSET  0xE
  17 #define SYSCALL_OLD     0x20CD
  18 #endif
  19
  20 static long intaddr;
  21
  22 void start_syscall(addr)
  23 long addr;
  24 {
  25 long old;
  26
  27   syscalls = FALSE;
  28
  29   if ( addr == 0 ) {
  30         intaddr = symbolvalue( SYSCALL_NAME, TRUE );
  31         if ( intaddr == 0 )
  32                 return;
  33         intaddr += SYSCALL_OFFSET;
  34   }
  35   else {
  36         intaddr = addr;
  37         Printf("Using %lx as syscall address\n",addr);
  38   }
  39
  40   old = breakpt(intaddr,"\n");
  41
  42   /* Check instruction */
  43   if ( (old & 0xFFFF) == SYSCALL_OLD)
  44         syscalls = TRUE;
  45
  46 }
  47
  48 void do_syscall(addr)
  49 long addr;
  50 {
  51   unsigned reg_ax,reg_bx;
  52
  53   if ( addr != intaddr ) return;
  54
  55   Printf("syscall to ");
  56
  57   reg_ax = get_reg(curpid,reg_addr("AX"));
  58
  59   switch (reg_ax) {
  60   case 0:       Printf(" PM ");
  61                 break;
  62   case 1:       Printf(" VFS ");
  63                 break;
  64   case 2:       Printf(" INET ");
  65                 break;
  66   default:      Printf("Invalid dest = %d", reg_ax);
  67                 exit(0);
  68   }
  69
  70
  71   reg_bx = get_reg(curpid,reg_addr("BX"));
  72   decode_message(reg_bx);
  73
  74   /* Single step */
  75   tstart(T_STEP, 0, 0, 1);
  76
  77   /* Check return code */
  78   reg_ax = get_reg(curpid,reg_addr("AX"));
  79   if ( reg_ax != 0 )
  80         Printf("syscall failed AX=%d\n",reg_ax);
  81   else
  82         decode_result();
  83 }
  84
  85 #endif /* SYSCALLS_SUPPORT */