minix/kernel/system/do_exec.c

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/* The kernel call implemented in this file:
* m_type: SYS_EXEC
*
* The parameters for this kernel call are:
* m1_i1: PR_PROC_NR (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 "../system.h"
#include <string.h>
#include <signal.h>
#if USE_EXEC
/*===========================================================================*
* do_exec *
*===========================================================================*/
PUBLIC int do_exec(m_ptr)
register message *m_ptr; /* pointer to request message */
{
/* Handle sys_exec(). A process has done a successful EXEC. Patch it up. */
register struct proc *rp;
reg_t sp; /* new sp */
phys_bytes phys_name;
char *np;
rp = proc_addr(m_ptr->PR_PROC_NR);
sp = (reg_t) m_ptr->PR_STACK_PTR;
rp->p_reg.sp = sp; /* set the stack pointer */
#if (CHIP == M68000)
rp->p_splow = sp; /* set the stack pointer low water */
#ifdef FPP
/* Initialize fpp for this process */
fpp_new_state(rp);
#endif
#endif
#if (CHIP == INTEL) /* wipe extra LDT entries */
phys_memset(vir2phys(&rp->p_ldt[EXTRA_LDT_INDEX]), 0,
(LDT_SIZE - EXTRA_LDT_INDEX) * sizeof(rp->p_ldt[0]));
#endif
rp->p_reg.pc = (reg_t) m_ptr->PR_IP_PTR; /* set pc */
rp->p_rts_flags &= ~RECEIVING; /* PM does not reply to EXEC call */
if (rp->p_rts_flags == 0) lock_enqueue(rp);
/* Save command name for debugging, ps(1) output, etc. */
phys_name = numap_local(m_ptr->m_source, (vir_bytes) m_ptr->PR_NAME_PTR,
(vir_bytes) P_NAME_LEN - 1);
if (phys_name != 0) {
phys_copy(phys_name, vir2phys(rp->p_name), (phys_bytes) P_NAME_LEN - 1);
for (np = rp->p_name; (*np & BYTE) >= ' '; np++) {}
*np = 0; /* mark end */
} else {
strncpy(rp->p_name, "<unset>", P_NAME_LEN);
}
return(OK);
}
#endif /* USE_EXEC */