minix/lib/libc/sys/ptrace.c

   1 #include <sys/cdefs.h>
   2 #include "namespace.h"
   3 #include <lib.h>
   4
   5 #include <string.h>
   6 #include <sys/ptrace.h>
   7
   8 int ptrace(int req, pid_t pid, void *addr, int data)
   9 {
  10   message m;
  11
  12   memset(&m, 0, sizeof(m));
  13   m.m_lc_pm_ptrace.pid = pid;
  14   m.m_lc_pm_ptrace.req = req;
  15   m.m_lc_pm_ptrace.addr = (vir_bytes)addr;
  16   m.m_lc_pm_ptrace.data = data;
  17   if (_syscall(PM_PROC_NR, PM_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.m_pm_lc_ptrace.data == -1) errno = 0;
  24   return(m.m_pm_lc_ptrace.data);
  25 }