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/* $OpenBSD: dt_prov_syscall.c,v 1.4 2020/07/04 10:19:09 mpi Exp $ */
/*
* Copyright (c) 2019 Martin Pieuchot <mpi@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/atomic.h>
#include <sys/syscall.h>
#include <dev/dt/dtvar.h>
extern struct sysent sysent[];
/* Arrays of probes per syscall. */
struct dt_probe **dtps_entry;
struct dt_probe **dtps_return;
unsigned int dtps_nsysent = SYS_MAXSYSCALL;
/* Flags that make sense for this provider */
#define DTEVT_PROV_SYSCALL (DTEVT_COMMON|DTEVT_FUNCARGS)
int dt_prov_syscall_alloc(struct dt_probe *, struct dt_softc *,
struct dt_pcb_list *, struct dtioc_req *);
void dt_prov_syscall_entry(struct dt_provider *, ...);
void dt_prov_syscall_return(struct dt_provider *, ...);
struct dt_provider dt_prov_syscall = {
.dtpv_name = "syscall",
.dtpv_alloc = dt_prov_syscall_alloc,
.dtpv_enter = dt_prov_syscall_entry,
.dtpv_leave = dt_prov_syscall_return,
};
int
dt_prov_syscall_init(void)
{
struct dt_probe *dtp;
int i, len, nprobes = 0;
char *sysnb;
dtps_entry = mallocarray(dtps_nsysent, sizeof(dtp), M_DT,
M_NOWAIT|M_ZERO);
if (dtps_entry == NULL)
return 0;
dtps_return = mallocarray(dtps_nsysent, sizeof(dtp), M_DT,
M_NOWAIT|M_ZERO);
if (dtps_return == NULL) {
free(dtps_entry, M_DT, dtps_nsysent * sizeof(dtp));
return 0;
}
for (i = 0; i < dtps_nsysent; i++) {
if (sysent[i].sy_call == sys_nosys)
continue;
len = snprintf(NULL, 0, "sys%%%u", i);
sysnb = malloc(len + 1, M_DT, M_NOWAIT);
if (sysnb == NULL)
break;
snprintf(sysnb, len + 1, "sys%%%u", i);
dtp = dt_dev_alloc_probe(sysnb, "entry", &dt_prov_syscall);
if (dtp == NULL) {
free(sysnb, M_DT, len);
break;
}
dtp->dtp_nargs = sysent[i].sy_narg;
dtp->dtp_sysnum = i;
dtps_entry[i] = dtp;
dt_dev_register_probe(dtp);
nprobes++;
dtp = dt_dev_alloc_probe(sysnb, "return", &dt_prov_syscall);
if (dtp == NULL)
break;
dtp->dtp_sysnum = i;
dtps_return[i] = dtp;
dt_dev_register_probe(dtp);
nprobes++;
}
return nprobes;
}
int
dt_prov_syscall_alloc(struct dt_probe *dtp, struct dt_softc *sc,
struct dt_pcb_list *plist, struct dtioc_req *dtrq)
{
struct dt_pcb *dp;
KASSERT(dtioc_req_isvalid(dtrq));
KASSERT(TAILQ_EMPTY(plist));
KASSERT(dtp->dtp_prov == &dt_prov_syscall);
KASSERT((dtp->dtp_sysnum >= 0) && (dtp->dtp_sysnum < dtps_nsysent));
dp = dt_pcb_alloc(dtp, sc);
if (dp == NULL)
return ENOMEM;
dp->dp_filter = dtrq->dtrq_filter;
dp->dp_evtflags = dtrq->dtrq_evtflags & DTEVT_PROV_SYSCALL;
TAILQ_INSERT_HEAD(plist, dp, dp_snext);
return 0;
}
void
dt_prov_syscall_entry(struct dt_provider *dtpv, ...)
{
struct dt_probe *dtp;
struct dt_pcb *dp;
register_t sysnum;
size_t argsize;
register_t *args;
va_list ap;
KASSERT(dtpv == &dt_prov_syscall);
va_start(ap, dtpv);
sysnum = va_arg(ap, register_t);
argsize = va_arg(ap, size_t);
args = va_arg(ap, register_t*);
va_end(ap);
KASSERT((argsize / sizeof(register_t)) <= DTMAXSYSARGS);
if (sysnum < 0 || sysnum >= dtps_nsysent)
return;
dtp = dtps_entry[sysnum];
if (!dtp->dtp_recording)
return;
smr_read_enter();
SMR_SLIST_FOREACH(dp, &dtp->dtp_pcbs, dp_pnext) {
struct dt_evt *dtev;
dtev = dt_pcb_ring_get(dp, 0);
if (dtev == NULL)
continue;
if (ISSET(dp->dp_evtflags, DTEVT_FUNCARGS))
memcpy(dtev->dtev_sysargs, args, argsize);
dt_pcb_ring_consume(dp, dtev);
}
smr_read_leave();
}
void
dt_prov_syscall_return(struct dt_provider *dtpv, ...)
{
struct dt_probe *dtp;
struct dt_pcb *dp;
register_t sysnum;
int error;
register_t retval[2];
va_list ap;
KASSERT(dtpv == &dt_prov_syscall);
va_start(ap, dtpv);
sysnum = va_arg(ap, register_t);
error = va_arg(ap, int);
retval[0] = va_arg(ap, register_t);
retval[1] = va_arg(ap, register_t);
va_end(ap);
if (sysnum < 0 || sysnum >= dtps_nsysent)
return;
dtp = dtps_return[sysnum];
if (!dtp->dtp_recording)
return;
smr_read_enter();
SMR_SLIST_FOREACH(dp, &dtp->dtp_pcbs, dp_pnext) {
struct dt_evt *dtev;
dtev = dt_pcb_ring_get(dp, 0);
if (dtev == NULL)
continue;
if (error) {
dtev->dtev_sysretval[0] = -1;
dtev->dtev_sysretval[1] = 0;
dtev->dtev_syserror = error;
} else {
dtev->dtev_sysretval[0] = retval[0];
dtev->dtev_sysretval[1] = retval[1];
dtev->dtev_syserror = 0;
}
dt_pcb_ring_consume(dp, dtev);
}
smr_read_leave();
}
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