/*
* Check to see if the control thread was requested to stop when the victim
* process reached a particular event (why) rather than continuing the victim.
* If 'why' is set in the stop mask, we wait on dpr_cv for dt_proc_continue().
* If 'why' is not set, this function returns immediately and does nothing.
*/
static void
dt_proc_stop(dt_proc_t *dpr, uint8_t why)
{
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
assert(why != DT_PROC_STOP_IDLE);
if (dpr->dpr_stop & why) {
dpr->dpr_stop |= DT_PROC_STOP_IDLE;
dpr->dpr_stop &= ~why;
(void) pthread_cond_broadcast(&dpr->dpr_cv);
/*
* We disable breakpoints while stopped to preserve the
* integrity of the program text for both our own disassembly
* and that of the kernel.
*/
dt_proc_bpdisable(dpr);
while (dpr->dpr_stop & DT_PROC_STOP_IDLE)
(void) pthread_cond_wait(&dpr->dpr_cv, &dpr->dpr_lock);
dt_proc_bpenable(dpr);
}
}
static void
dt_proc_bpmatch(dtrace_hdl_t *dtp, dt_proc_t *dpr)
{
const lwpstatus_t *psp = &Pstatus(dpr->dpr_proc)->pr_lwp;
dt_bkpt_t *dbp;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
for (dbp = dt_list_next(&dpr->dpr_bps);
dbp != NULL; dbp = dt_list_next(dbp)) {
if (psp->pr_reg[R_PC] == dbp->dbp_addr)
break;
}
if (dbp == NULL) {
dt_dprintf("pid %d: spurious breakpoint wakeup for %lx\n",
(int)dpr->dpr_pid, (ulong_t)psp->pr_reg[R_PC]);
return;
}
dt_dprintf("pid %d: hit breakpoint at %lx (%lu)\n",
(int)dpr->dpr_pid, (ulong_t)dbp->dbp_addr, ++dbp->dbp_hits);
dbp->dbp_func(dtp, dpr, dbp->dbp_data);
(void) Pxecbkpt(dpr->dpr_proc, dbp->dbp_instr);
}
static void
dt_proc_bpdestroy(dt_proc_t *dpr, int delbkpts)
{
#if defined(sun)
int state = Pstate(dpr->dpr_proc);
#else
int state = proc_state(dpr->dpr_proc);
#endif
dt_bkpt_t *dbp, *nbp;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
for (dbp = dt_list_next(&dpr->dpr_bps); dbp != NULL; dbp = nbp) {
printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
#ifdef DOODAD
if (delbkpts && dbp->dbp_active &&
state != PS_LOST && state != PS_UNDEAD) {
(void) Pdelbkpt(dpr->dpr_proc,
dbp->dbp_addr, dbp->dbp_instr);
}
#endif
nbp = dt_list_next(dbp);
dt_list_delete(&dpr->dpr_bps, dbp);
dt_free(dpr->dpr_hdl, dbp);
}
}
/*
* Wait for a stopped process to be set running again by some other debugger.
* This is typically not required by /proc-based debuggers, since the usual
* model is that one debugger controls one victim. But DTrace, as usual, has
* its own needs: the stop() action assumes that prun(1) or some other tool
* will be applied to resume the victim process. This could be solved by
* adding a PCWRUN directive to /proc, but that seems like overkill unless
* other debuggers end up needing this functionality, so we implement a cheap
* equivalent to PCWRUN using the set of existing kernel mechanisms.
*
* Our intent is really not just to wait for the victim to run, but rather to
* wait for it to run and then stop again for a reason other than the current
* PR_REQUESTED stop. Since PCWSTOP/Pstopstatus() can be applied repeatedly
* to a stopped process and will return the same result without affecting the
* victim, we can just perform these operations repeatedly until Pstate()
* changes, the representative LWP ID changes, or the stop timestamp advances.
* dt_gproc_control() will then rediscover the new state and continue as usual.
* When the process is still stopped in the same exact state, we sleep for a
* brief interval before waiting again so as not to spin consuming CPU cycles.
*/
static void
dt_proc_waitrun(dt_proc_t *dpr)
{
struct ps_prochandle *P = dpr->dpr_proc;
const lwpstatus_t *psp = &Pstatus(P)->pr_lwp;
int krflag = psp->pr_flags & (PR_KLC | PR_RLC);
timestruc_t tstamp = psp->pr_tstamp;
lwpid_t lwpid = psp->pr_lwpid;
const long wstop = PCWSTOP;
int pfd = Pctlfd(P);
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
assert(psp->pr_flags & PR_STOPPED);
assert(Pstate(P) == PS_STOP);
/*
* While we are waiting for the victim to run, clear PR_KLC and PR_RLC
* so that if the libdtrace client is killed, the victim stays stopped.
* dt_proc_destroy() will also observe this and perform PRELEASE_HANG.
*/
(void) Punsetflags(P, krflag);
Psync(P);
(void) pthread_mutex_unlock(&dpr->dpr_lock);
while (!dpr->dpr_quit) {
if (write(pfd, &wstop, sizeof (wstop)) == -1 && errno == EINTR)
continue; /* check dpr_quit and continue waiting */
(void) pthread_mutex_lock(&dpr->dpr_lock);
(void) Pstopstatus(P, PCNULL, 0);
psp = &Pstatus(P)->pr_lwp;
/*
* If we've reached a new state, found a new representative, or
* the stop timestamp has changed, restore PR_KLC/PR_RLC to its
* original setting and then return with dpr_lock held.
*/
if (Pstate(P) != PS_STOP || psp->pr_lwpid != lwpid ||
bcmp(&psp->pr_tstamp, &tstamp, sizeof (tstamp)) != 0) {
(void) Psetflags(P, krflag);
Psync(P);
return;
}
(void) pthread_mutex_unlock(&dpr->dpr_lock);
(void) poll(NULL, 0, MILLISEC / 2);
}
(void) pthread_mutex_lock(&dpr->dpr_lock);
}
static void
dt_proc_bpdisable(dt_proc_t *dpr)
{
dt_bkpt_t *dbp;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
for (dbp = dt_list_next(&dpr->dpr_bps);
dbp != NULL; dbp = dt_list_next(dbp)) {
if (dbp->dbp_active && Pdelbkpt(dpr->dpr_proc,
dbp->dbp_addr, dbp->dbp_instr) == 0)
dbp->dbp_active = B_FALSE;
}
dt_dprintf("breakpoints disabled\n");
}
static void
dt_proc_bpdestroy(dt_proc_t *dpr, int delbkpts)
{
int state = Pstate(dpr->dpr_proc);
dt_bkpt_t *dbp, *nbp;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
for (dbp = dt_list_next(&dpr->dpr_bps); dbp != NULL; dbp = nbp) {
if (delbkpts && dbp->dbp_active &&
state != PS_LOST && state != PS_UNDEAD) {
(void) Pdelbkpt(dpr->dpr_proc,
dbp->dbp_addr, dbp->dbp_instr);
}
nbp = dt_list_next(dbp);
dt_list_delete(&dpr->dpr_bps, dbp);
dt_free(dpr->dpr_hdl, dbp);
}
}
static void
dt_proc_bpdisable(dt_proc_t *dpr)
{
dt_bkpt_t *dbp;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
for (dbp = dt_list_next(&dpr->dpr_bps);
dbp != NULL; dbp = dt_list_next(dbp)) {
printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
#ifdef DOODAD
if (dbp->dbp_active && Pdelbkpt(dpr->dpr_proc,
dbp->dbp_addr, dbp->dbp_instr) == 0)
dbp->dbp_active = B_FALSE;
#endif
}
dt_dprintf("breakpoints disabled\n");
}
static int
dt_pid_create_usdt_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
dt_pcb_t *pcb, dt_proc_t *dpr)
{
struct ps_prochandle *P = dpr->dpr_proc;
int ret = 0;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
#if defined(sun)
(void) Pupdate_maps(P);
if (Pobject_iter(P, dt_pid_usdt_mapping, P) != 0) {
ret = -1;
(void) dt_pid_error(dtp, pcb, dpr, NULL, D_PROC_USDT,
"failed to instantiate probes for pid %d: %s",
#if defined(sun)
(int)Pstatus(P)->pr_pid, strerror(errno));
#else
(int)proc_getpid(P), strerror(errno));
#endif
}
static dt_bkpt_t *
dt_proc_bpcreate(dt_proc_t *dpr, uintptr_t addr, dt_bkpt_f *func, void *data)
{
struct ps_prochandle *P = dpr->dpr_proc;
dt_bkpt_t *dbp;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
if ((dbp = dt_zalloc(dpr->dpr_hdl, sizeof (dt_bkpt_t))) != NULL) {
dbp->dbp_func = func;
dbp->dbp_data = data;
dbp->dbp_addr = addr;
if (Psetbkpt(P, dbp->dbp_addr, &dbp->dbp_instr) == 0)
dbp->dbp_active = B_TRUE;
dt_list_append(&dpr->dpr_bps, dbp);
}
return (dbp);
}
/*
* Common code for enabling events associated with the run-time linker after
* attaching to a process or after a victim process completes an exec(2).
*/
static void
dt_proc_attach(dt_proc_t *dpr, int exec)
{
const pstatus_t *psp = Pstatus(dpr->dpr_proc);
rd_err_e err;
GElf_Sym sym;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
if (exec) {
if (psp->pr_lwp.pr_errno != 0)
return; /* exec failed: nothing needs to be done */
dt_proc_bpdestroy(dpr, B_FALSE);
Preset_maps(dpr->dpr_proc);
}
if ((dpr->dpr_rtld = Prd_agent(dpr->dpr_proc)) != NULL &&
(err = rd_event_enable(dpr->dpr_rtld, B_TRUE)) == RD_OK) {
dt_proc_rdwatch(dpr, RD_PREINIT, "RD_PREINIT");
dt_proc_rdwatch(dpr, RD_POSTINIT, "RD_POSTINIT");
dt_proc_rdwatch(dpr, RD_DLACTIVITY, "RD_DLACTIVITY");
} else {
dt_dprintf("pid %d: failed to enable rtld events: %s\n",
(int)dpr->dpr_pid, dpr->dpr_rtld ? rd_errstr(err) :
"rtld_db agent initialization failed");
}
Pupdate_maps(dpr->dpr_proc);
if (Pxlookup_by_name(dpr->dpr_proc, LM_ID_BASE,
"a.out", "main", &sym, NULL) == 0) {
(void) dt_proc_bpcreate(dpr, (uintptr_t)sym.st_value,
(dt_bkpt_f *)dt_proc_bpmain, "a.out`main");
} else {
dt_dprintf("pid %d: failed to find a.out`main: %s\n",
(int)dpr->dpr_pid, strerror(errno));
}
}
static void
dt_proc_bpmatch(dtrace_hdl_t *dtp, dt_proc_t *dpr)
{
#ifdef illumos
const lwpstatus_t *psp = &Pstatus(dpr->dpr_proc)->pr_lwp;
#else
unsigned long pc;
#endif
dt_bkpt_t *dbp;
assert(DT_MUTEX_HELD(&dpr->dpr_lock));
#ifndef illumos
proc_regget(dpr->dpr_proc, REG_PC, &pc);
proc_bkptregadj(&pc);
#endif
for (dbp = dt_list_next(&dpr->dpr_bps);
dbp != NULL; dbp = dt_list_next(dbp)) {
#ifdef illumos
if (psp->pr_reg[R_PC] == dbp->dbp_addr)
break;
#else
if (pc == dbp->dbp_addr)
break;
#endif
}
if (dbp == NULL) {
dt_dprintf("pid %d: spurious breakpoint wakeup for %lx\n",
#ifdef illumos
(int)dpr->dpr_pid, (ulong_t)psp->pr_reg[R_PC]);
#else
(int)dpr->dpr_pid, pc);
#endif
return;
}
