minix/kernel/system/tracing.c

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2005-04-21 16:53:53 +02:00
/* The system call implemented in this file:
* m_type: SYS_TRACE
*
* The parameters for this system call are:
* m2_i1: CTL_PROC_NR process that is traced
* m2_i2: CTL_REQUEST trace request
* m2_l1: CTL_ADDRESS address at traced process' space
* m2_l2: CTL_DATA data to be written or returned here
*/
#include "../kernel.h"
#include "../system.h"
#include <sys/ptrace.h>
#if ENABLE_K_TRACING /* only include code if tracing is enabled */
/*==========================================================================*
* do_trace *
*==========================================================================*/
#define TR_VLSIZE ((vir_bytes) sizeof(long))
PUBLIC int do_trace(m_ptr)
register message *m_ptr;
{
/* Handle the debugging commands supported by the ptrace system call
* The commands are:
* T_STOP stop the process
* T_OK enable tracing by parent for this process
* T_GETINS return value from instruction space
* T_GETDATA return value from data space
* T_GETUSER return value from user process table
* T_SETINS set value from instruction space
* T_SETDATA set value from data space
* T_SETUSER set value in user process table
* T_RESUME resume execution
* T_EXIT exit
* T_STEP set trace bit
*
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* The T_OK and T_EXIT commands are handled completely by the process manager,
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* all others come here.
*/
register struct proc *rp;
phys_bytes src, dst;
vir_bytes tr_addr = (vir_bytes) m_ptr->CTL_ADDRESS;
long tr_data = m_ptr->CTL_DATA;
int tr_request = m_ptr->CTL_REQUEST;
int tr_proc_nr = m_ptr->CTL_PROC_NR;
int i;
rp = proc_addr(tr_proc_nr);
if (isemptyp(rp)) return(EIO);
switch (tr_request) {
case T_STOP: /* stop process */
if (rp->p_flags == 0) lock_unready(rp);
rp->p_flags |= P_STOP;
rp->p_reg.psw &= ~TRACEBIT; /* clear trace bit */
return(OK);
case T_GETINS: /* return value from instruction space */
if (rp->p_memmap[T].mem_len != 0) {
if ((src = umap_local(rp, T, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(src, vir2phys(&tr_data), (phys_bytes) sizeof(long));
break;
}
/* Text space is actually data space - fall through. */
case T_GETDATA: /* return value from data space */
if ((src = umap_local(rp, D, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(src, vir2phys(&tr_data), (phys_bytes) sizeof(long));
break;
case T_GETUSER: /* return value from process table */
if ((tr_addr & (sizeof(long) - 1)) != 0 ||
tr_addr > sizeof(struct proc) - sizeof(long))
return(EIO);
tr_data = *(long *) ((char *) rp + (int) tr_addr);
break;
case T_SETINS: /* set value in instruction space */
if (rp->p_memmap[T].mem_len != 0) {
if ((dst = umap_local(rp, T, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(vir2phys(&tr_data), dst, (phys_bytes) sizeof(long));
tr_data = 0;
break;
}
/* Text space is actually data space - fall through. */
case T_SETDATA: /* set value in data space */
if ((dst = umap_local(rp, D, tr_addr, TR_VLSIZE)) == 0) return(EIO);
phys_copy(vir2phys(&tr_data), dst, (phys_bytes) sizeof(long));
tr_data = 0;
break;
case T_SETUSER: /* set value in process table */
if ((tr_addr & (sizeof(reg_t) - 1)) != 0 ||
tr_addr > sizeof(struct stackframe_s) - sizeof(reg_t))
return(EIO);
i = (int) tr_addr;
#if (CHIP == INTEL)
/* Altering segment registers might crash the kernel when it
* tries to load them prior to restarting a process, so do
* not allow it.
*/
if (i == (int) &((struct proc *) 0)->p_reg.cs ||
i == (int) &((struct proc *) 0)->p_reg.ds ||
i == (int) &((struct proc *) 0)->p_reg.es ||
#if _WORD_SIZE == 4
i == (int) &((struct proc *) 0)->p_reg.gs ||
i == (int) &((struct proc *) 0)->p_reg.fs ||
#endif
i == (int) &((struct proc *) 0)->p_reg.ss)
return(EIO);
#endif
if (i == (int) &((struct proc *) 0)->p_reg.psw)
/* only selected bits are changeable */
SETPSW(rp, tr_data);
else
*(reg_t *) ((char *) &rp->p_reg + i) = (reg_t) tr_data;
tr_data = 0;
break;
case T_RESUME: /* resume execution */
rp->p_flags &= ~P_STOP;
if (rp->p_flags == 0) lock_ready(rp);
tr_data = 0;
break;
case T_STEP: /* set trace bit */
rp->p_reg.psw |= TRACEBIT;
rp->p_flags &= ~P_STOP;
if (rp->p_flags == 0) lock_ready(rp);
tr_data = 0;
break;
default:
return(EIO);
}
return(OK);
}
#endif /* ENABLE_K_TRACING */