130 lines
4.1 KiB
C
130 lines
4.1 KiB
C
/* The kernel call implemented in this file:
|
|
* m_type: SYS_FORK
|
|
*
|
|
* The parameters for this kernel call are:
|
|
* m1_i1: PR_ENDPT (parent, process that forked)
|
|
* m1_i2: PR_SLOT (child's process table slot)
|
|
* m1_p1: PR_MEM_PTR (new memory map for the child)
|
|
* m1_i3: PR_FORK_FLAGS (fork flags)
|
|
*/
|
|
|
|
#include "kernel/system.h"
|
|
#include "kernel/vm.h"
|
|
#include <signal.h>
|
|
#include <string.h>
|
|
#include <assert.h>
|
|
|
|
#include <minix/endpoint.h>
|
|
#include <minix/u64.h>
|
|
|
|
#if USE_FORK
|
|
|
|
/*===========================================================================*
|
|
* do_fork *
|
|
*===========================================================================*/
|
|
PUBLIC int do_fork(struct proc * caller, message * m_ptr)
|
|
{
|
|
/* Handle sys_fork(). PR_ENDPT has forked. The child is PR_SLOT. */
|
|
#if (_MINIX_CHIP == _CHIP_INTEL)
|
|
reg_t old_ldt_sel;
|
|
void *old_fpu_save_area_p;
|
|
#endif
|
|
register struct proc *rpc; /* child process pointer */
|
|
struct proc *rpp; /* parent process pointer */
|
|
struct mem_map *map_ptr; /* virtual address of map inside caller (PM) */
|
|
int gen, r;
|
|
int p_proc;
|
|
|
|
if(!isokendpt(m_ptr->PR_ENDPT, &p_proc))
|
|
return EINVAL;
|
|
|
|
rpp = proc_addr(p_proc);
|
|
rpc = proc_addr(m_ptr->PR_SLOT);
|
|
if (isemptyp(rpp) || ! isemptyp(rpc)) return(EINVAL);
|
|
|
|
assert(!(rpp->p_misc_flags & MF_DELIVERMSG));
|
|
|
|
/* needs to be receiving so we know where the message buffer is */
|
|
if(!RTS_ISSET(rpp, RTS_RECEIVING)) {
|
|
printf("kernel: fork not done synchronously?\n");
|
|
return EINVAL;
|
|
}
|
|
|
|
map_ptr= (struct mem_map *) m_ptr->PR_MEM_PTR;
|
|
|
|
/* make sure that the FPU context is saved in parent before copy */
|
|
if (fpu_owner == rpp) {
|
|
disable_fpu_exception();
|
|
save_fpu(rpp);
|
|
}
|
|
/* Copy parent 'proc' struct to child. And reinitialize some fields. */
|
|
gen = _ENDPOINT_G(rpc->p_endpoint);
|
|
#if (_MINIX_CHIP == _CHIP_INTEL)
|
|
old_ldt_sel = rpc->p_seg.p_ldt_sel; /* backup local descriptors */
|
|
old_fpu_save_area_p = rpc->p_fpu_state.fpu_save_area_p;
|
|
#endif
|
|
*rpc = *rpp; /* copy 'proc' struct */
|
|
#if (_MINIX_CHIP == _CHIP_INTEL)
|
|
rpc->p_seg.p_ldt_sel = old_ldt_sel; /* restore descriptors */
|
|
rpc->p_fpu_state.fpu_save_area_p = old_fpu_save_area_p;
|
|
if(proc_used_fpu(rpp))
|
|
memcpy(rpc->p_fpu_state.fpu_save_area_p,
|
|
rpp->p_fpu_state.fpu_save_area_p,
|
|
FPU_XFP_SIZE);
|
|
#endif
|
|
if(++gen >= _ENDPOINT_MAX_GENERATION) /* increase generation */
|
|
gen = 1; /* generation number wraparound */
|
|
rpc->p_nr = m_ptr->PR_SLOT; /* this was obliterated by copy */
|
|
rpc->p_endpoint = _ENDPOINT(gen, rpc->p_nr); /* new endpoint of slot */
|
|
|
|
rpc->p_reg.retreg = 0; /* child sees pid = 0 to know it is child */
|
|
rpc->p_user_time = 0; /* set all the accounting times to 0 */
|
|
rpc->p_sys_time = 0;
|
|
|
|
rpc->p_reg.psw &= ~TRACEBIT; /* clear trace bit */
|
|
rpc->p_misc_flags &= ~(MF_VIRT_TIMER | MF_PROF_TIMER | MF_SC_TRACE);
|
|
rpc->p_virt_left = 0; /* disable, clear the process-virtual timers */
|
|
rpc->p_prof_left = 0;
|
|
|
|
/* the child process is not runnable until it's scheduled. */
|
|
RTS_SET(rpc, RTS_NO_QUANTUM);
|
|
|
|
make_zero64(rpc->p_cpu_time_left);
|
|
make_zero64(rpc->p_cycles);
|
|
|
|
/* If the parent is a privileged process, take away the privileges from the
|
|
* child process and inhibit it from running by setting the NO_PRIV flag.
|
|
* The caller should explicitely set the new privileges before executing.
|
|
*/
|
|
if (priv(rpp)->s_flags & SYS_PROC) {
|
|
rpc->p_priv = priv_addr(USER_PRIV_ID);
|
|
rpc->p_rts_flags |= RTS_NO_PRIV;
|
|
}
|
|
|
|
/* Calculate endpoint identifier, so caller knows what it is. */
|
|
m_ptr->PR_ENDPT = rpc->p_endpoint;
|
|
m_ptr->PR_FORK_MSGADDR = (char *) rpp->p_delivermsg_vir;
|
|
|
|
/* Install new map */
|
|
r = newmap(caller, rpc, map_ptr);
|
|
|
|
/* Don't schedule process in VM mode until it has a new pagetable. */
|
|
if(m_ptr->PR_FORK_FLAGS & PFF_VMINHIBIT) {
|
|
RTS_SET(rpc, RTS_VMINHIBIT);
|
|
}
|
|
|
|
/*
|
|
* Only one in group should have RTS_SIGNALED, child doesn't inherit tracing.
|
|
*/
|
|
RTS_UNSET(rpc, (RTS_SIGNALED | RTS_SIG_PENDING | RTS_P_STOP));
|
|
(void) sigemptyset(&rpc->p_pending);
|
|
|
|
rpc->p_seg.p_cr3 = 0;
|
|
rpc->p_seg.p_cr3_v = NULL;
|
|
|
|
return r;
|
|
}
|
|
|
|
#endif /* USE_FORK */
|
|
|