sysproc.c

#include "types.h"
#include "x86.h"
#include "defs.h"
#include "param.h"
#include "memlayout.h"
#include "mmu.h"
#include "proc.h"

int
sys_fork(void)
{
  return fork();
}

int
sys_exit(void)
{
  exit();
  return 0;  // not reached
}

int
sys_wait(void)
{
  return wait();
}

int
sys_kill(void)
{
  int pid;

  if(argint(0, &pid) < 0)
    return -1;
  return kill(pid);
}

int
sys_getpid(void)
{
  return proc->pid;
}

int
sys_sbrk(void)
{
  int addr;
  int n;

  if(argint(0, &n) < 0)
    return -1;
  addr = proc->sz;
// Eliminate allocation from sbrk()
  proc->sz += n;
/*
  if(growproc(n) < 0)
    return -1;
*/
  return addr;
}

int
sys_sleep(void)
{
  int n;
  uint ticks0;
  
  if(argint(0, &n) < 0)
    return -1;
  acquire(&tickslock);
  ticks0 = ticks;
  while(ticks - ticks0 < n){
    if(proc->killed){
      release(&tickslock);
      return -1;
    }
    sleep(&ticks, &tickslock);
  }
  release(&tickslock);
  return 0;
}

// return how many clock tick interrupts have occurred
// since start.
int
sys_uptime(void)
{
  uint xticks;
  
  acquire(&tickslock);
  xticks = ticks;
  release(&tickslock);
  return xticks;
}

// halt system call, telling QEMU to exit.
int 
sys_halt(void)
{
  cprintf("calling sys_halt\n");
  char *p = "Shutdown";
  for( ; *p; p++)
    outb(0x8900, *p);
  return 0;
}

// xv6 CPU alarm
int
sys_alarm(void)
{
  int ticks;
  void (*handler)(void);
  
  if(argint(0, &ticks) < 0)
    return -1;
  if(argptr(1, (char**)&handler, 1) < 0)
    return -1;
  proc->alarmticks = ticks;
  proc->alarmhandler = handler;
  proc->alarmsignal = ASIG_NACTIVATED;
//  cprintf("handler %p\n", handler);
//  handler();
  return 0;
}