kernel/system/do_exec.c
/* The kernel call implemented in this file:
 *   m_type:	SYS_EXEC
 *
 * The parameters for this kernel call are:
 *    m1_i1:	PR_ENDPT  		(process that did exec call)
 *    m1_p1:	PR_STACK_PTR		(new stack pointer)
 *    m1_p2:	PR_NAME_PTR		(pointer to program name)
 *    m1_p3:	PR_IP_PTR		(new instruction pointer)
 */
#include "kernel/system.h"
#include <string.h>
#include <minix/endpoint.h>

#if USE_EXEC

/*===========================================================================*
 *				do_exec					     *
 *===========================================================================*/
int do_exec(struct proc * caller, message * m_ptr)
{
/* Handle sys_exec().  A process has done a successful EXEC. Patch it up. */
  register struct proc *rp;
  int proc_nr;
  char name[PROC_NAME_LEN];

  if(!isokendpt(m_ptr->PR_ENDPT, &proc_nr))
	return EINVAL;

  rp = proc_addr(proc_nr);

  if(rp->p_misc_flags & MF_DELIVERMSG) {
	rp->p_misc_flags &= ~MF_DELIVERMSG;
  }

  /* Save command name for debugging, ps(1) output, etc. */
  if(data_copy(caller->p_endpoint, (vir_bytes) m_ptr->PR_NAME_PTR,
	KERNEL, (vir_bytes) name,
	(phys_bytes) sizeof(name) - 1) != OK)
  	strncpy(name, "<unset>", PROC_NAME_LEN);

  name[sizeof(name)-1] = '\0';

  /* Set process state. */
  arch_proc_init(rp, (u32_t) m_ptr->PR_IP_PTR, (u32_t) m_ptr->PR_STACK_PTR, name);

  /* No reply to EXEC call */
  RTS_UNSET(rp, RTS_RECEIVING);

  /* Mark fpu_regs contents as not significant, so fpu
   * will be initialized, when it's used next time. */
  rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
  /* force reloading FPU if the current process is the owner */
  release_fpu(rp);
  return(OK);
}
#endif /* USE_EXEC */

