lib/libc/posix/_ptrace.c

   1 #include <lib.h>
   2 #define ptrace  _ptrace
   3 #include <unistd.h>
   4
   5 PUBLIC long ptrace(req, pid, addr, data)
   6 int req;
   7 pid_t pid;
   8 long addr;
   9 long data;
  10 {
  11   message m;
  12
  13   m.m2_i1 = pid;
  14   m.m2_i2 = req;
  15   m.PMTRACE_ADDR = addr;
  16   m.m2_l2 = data;
  17   if (_syscall(MM, PTRACE, &m) < 0) return(-1);
  18
  19   /* There was no error, but -1 is a legal return value.  Clear errno if
  20    * necessary to distinguish this case.  _syscall has set errno to nonzero
  21    * for the error case.
  22    */
  23   if (m.m2_l2 == -1) errno = 0;
  24   return(m.m2_l2);
  25 }