pcontrol.c

Sun Solaris 10 中的 DTrace 组件的源代码。请参看: http://www.sun.com/software/solaris/observability.jsp

	cwp->pr_vaddr = wp->pr_vaddr;
	cwp->pr_size = wp->pr_size;
	cwp->pr_wflags = wp->pr_wflags;

	if (write(P->ctlfd, ctl, sizeof (ctl)) != sizeof (ctl))
		return (-1);

	return (0);
}

/*
 * Remove the watchpoint described by wp.
 */
int
Pdelwapt(struct ps_prochandle *P, const prwatch_t *wp)
{
	long ctl[1 + sizeof (prwatch_t) / sizeof (long)];
	prwatch_t *cwp = (prwatch_t *)&ctl[1];

	if (P->state == PS_DEAD || P->state == PS_UNDEAD ||
	    P->state == PS_IDLE) {
		errno = ENOENT;
		return (-1);
	}

	ctl[0] = PCWATCH;
	cwp->pr_vaddr = wp->pr_vaddr;
	cwp->pr_size = wp->pr_size;
	cwp->pr_wflags = 0;

	if (write(P->ctlfd, ctl, sizeof (ctl)) != sizeof (ctl))
		return (-1);

	return (0);
}

/*
 * Common code for Pxecwapt() and Lxecwapt().  Develop the array of requests
 * that will do the job, then write them to the specified control file
 * descriptor.  Return the non-zero errno if the write fails.
 */
static int
execute_wapt(
	int ctlfd,		/* process or LWP control file descriptor */
	const fltset_t *faultset,	/* current set of traced faults */
	const sigset_t *sigmask,	/* current signal mask */
	const prwatch_t *wp)		/* watchpoint descriptor */
{
	long ctl[
	    1 + sizeof (sigset_t) / sizeof (long) +		/* PCSHOLD */
	    1 + sizeof (fltset_t) / sizeof (long) +		/* PCSFAULT */
	    1 + sizeof (prwatch_t) / sizeof (long) +		/* PCWATCH */
	    2 +							/* PCRUN */
	    1 +							/* PCWSTOP */
	    1 +							/* PCCFAULT */
	    1 + sizeof (prwatch_t) / sizeof (long) +		/* PCWATCH */
	    1 + sizeof (fltset_t) / sizeof (long) +		/* PCSFAULT */
	    1 + sizeof (sigset_t) / sizeof (long)];		/* PCSHOLD */

	long *ctlp = ctl;
	int error = 0;

	sigset_t unblock;
	sigset_t *holdp;
	fltset_t *faultp;
	prwatch_t *prw;
	ssize_t ssize;
	size_t size;

	(void) sigprocmask(SIG_BLOCK, &blockable_sigs, &unblock);

	/*
	 * Hold all posted signals in the victim process prior to stepping.
	 */
	*ctlp++ = PCSHOLD;
	holdp = (sigset_t *)ctlp;
	prfillset(holdp);
	prdelset(holdp, SIGKILL);
	prdelset(holdp, SIGSTOP);
	ctlp += sizeof (sigset_t) / sizeof (long);

	/*
	 * Force tracing of FLTTRACE since we need to single step.
	 */
	if (!(prismember(faultset, FLTTRACE))) {
		*ctlp++ = PCSFAULT;
		faultp = (fltset_t *)ctlp;
		*faultp = *faultset;
		praddset(faultp, FLTTRACE);
		ctlp += sizeof (fltset_t) / sizeof (long);
	}

	/*
	 * Clear only the current watchpoint by setting pr_wflags to zero.
	 */
	*ctlp++ = PCWATCH;
	prw = (prwatch_t *)ctlp;
	prw->pr_vaddr = wp->pr_vaddr;
	prw->pr_size = wp->pr_size;
	prw->pr_wflags = 0;
	ctlp += sizeof (prwatch_t) / sizeof (long);

	/*
	 * Clear the current signal and fault; set running with single-step.
	 * Then wait for the victim to stop and cancel the FLTTRACE.
	 */
	*ctlp++ = PCRUN;
	*ctlp++ = PRCSIG | PRCFAULT | PRSTEP;
	*ctlp++ = PCWSTOP;
	*ctlp++ = PCCFAULT;

	/*
	 * Restore the current watchpoint.
	 */
	*ctlp++ = PCWATCH;
	(void) memcpy(ctlp, wp, sizeof (prwatch_t));
	ctlp += sizeof (prwatch_t) / sizeof (long);

	/*
	 * Restore fault tracing set if we modified it.
	 */
	if (!(prismember(faultset, FLTTRACE))) {
		*ctlp++ = PCSFAULT;
		*(fltset_t *)ctlp = *faultset;
		ctlp += sizeof (fltset_t) / sizeof (long);
	}

	/*
	 * Restore the hold mask to the current hold mask (i.e. the one
	 * before we executed any of the previous operations).
	 */
	*ctlp++ = PCSHOLD;
	*(sigset_t *)ctlp = *sigmask;
	ctlp += sizeof (sigset_t) / sizeof (long);

	size = (char *)ctlp - (char *)ctl;
	if ((ssize = write(ctlfd, ctl, size)) != size)
		error = (ssize == -1)? errno : EINTR;
	(void) sigprocmask(SIG_SETMASK, &unblock, NULL);
	return (error);
}

/*
 * Step over a watchpoint, i.e., execute the instruction that was stopped by
 * the watchpoint, and then leave the LWP stopped at the next instruction.
 */
int
Pxecwapt(struct ps_prochandle *P, const prwatch_t *wp)
{
	int ctlfd = (P->agentctlfd >= 0)? P->agentctlfd : P->ctlfd;
	int rv, error;

	if (P->state != PS_STOP) {
		errno = EBUSY;
		return (-1);
	}

	Psync(P);
	error = execute_wapt(ctlfd,
		&P->status.pr_flttrace, &P->status.pr_lwp.pr_lwphold, wp);
	rv = Pstopstatus(P, PCNULL, 0);

	if (error != 0) {
		if (P->status.pr_lwp.pr_why == PR_JOBCONTROL &&
		    error == EBUSY) {	/* jobcontrol stop -- back off */
			P->state = PS_RUN;
			return (0);
		}
		if (error == ENOENT)
			return (0);
		errno = error;
		return (-1);
	}

	return (rv);
}

int
Psetflags(struct ps_prochandle *P, long flags)
{
	int rc;
	long ctl[2];

	ctl[0] = PCSET;
	ctl[1] = flags;

	if (write(P->ctlfd, ctl, 2*sizeof (long)) != 2*sizeof (long)) {
		rc = -1;
	} else {
		P->status.pr_flags |= flags;
		P->status.pr_lwp.pr_flags |= flags;
		rc = 0;
	}

	return (rc);
}

int
Punsetflags(struct ps_prochandle *P, long flags)
{
	int rc;
	long ctl[2];

	ctl[0] = PCUNSET;
	ctl[1] = flags;

	if (write(P->ctlfd, ctl, 2*sizeof (long)) != 2*sizeof (long)) {
		rc = -1;
	} else {
		P->status.pr_flags &= ~flags;
		P->status.pr_lwp.pr_flags &= ~flags;
		rc = 0;
	}

	return (rc);
}

/*
 * Common function to allow clients to manipulate the action to be taken
 * on receipt of a signal, receipt of machine fault, entry to a system call,
 * or exit from a system call.  We make use of our private prset_* functions
 * in order to make this code be common.  The 'which' parameter identifies
 * the code for the event of interest (0 means change the entire set), and
 * the 'stop' parameter is a boolean indicating whether the process should
 * stop when the event of interest occurs.  The previous value is returned
 * to the caller; -1 is returned if an error occurred.
 */
static int
Psetaction(struct ps_prochandle *P, void *sp, size_t size,
    uint_t flag, int max, int which, int stop)
{
	int oldval;

	if (which < 0 || which > max) {
		errno = EINVAL;
		return (-1);
	}

	if (P->state == PS_DEAD || P->state == PS_UNDEAD ||
	    P->state == PS_IDLE) {
		errno = ENOENT;
		return (-1);
	}

	oldval = prset_ismember(sp, size, which) ? TRUE : FALSE;

	if (stop) {
		if (which == 0) {
			prset_fill(sp, size);
			P->flags |= flag;
		} else if (!oldval) {
			prset_add(sp, size, which);
			P->flags |= flag;
		}
	} else {
		if (which == 0) {
			prset_empty(sp, size);
			P->flags |= flag;
		} else if (oldval) {
			prset_del(sp, size, which);
			P->flags |= flag;
		}
	}

	if (P->state == PS_RUN)
		Psync(P);

	return (oldval);
}

/*
 * Set action on specified signal.
 */
int
Psignal(struct ps_prochandle *P, int which, int stop)
{
	int oldval;

	if (which == SIGKILL && stop != 0) {
		errno = EINVAL;
		return (-1);
	}

	oldval = Psetaction(P, &P->status.pr_sigtrace, sizeof (sigset_t),
	    SETSIG, PRMAXSIG, which, stop);

	if (oldval != -1 && which == 0 && stop != 0)
		prdelset(&P->status.pr_sigtrace, SIGKILL);

	return (oldval);
}

/*
 * Set all signal tracing flags.
 */
void
Psetsignal(struct ps_prochandle *P, const sigset_t *set)
{
	if (P->state == PS_DEAD || P->state == PS_UNDEAD ||
	    P->state == PS_IDLE)
		return;

	P->status.pr_sigtrace = *set;
	P->flags |= SETSIG;

	if (P->state == PS_RUN)
		Psync(P);
}

/*
 * Set action on specified fault.
 */
int
Pfault(struct ps_prochandle *P, int which, int stop)
{
	return (Psetaction(P, &P->status.pr_flttrace, sizeof (fltset_t),
	    SETFAULT, PRMAXFAULT, which, stop));
}

/*
 * Set all machine fault tracing flags.
 */
void
Psetfault(struct ps_prochandle *P, const fltset_t *set)
{
	if (P->state == PS_DEAD || P->state == PS_UNDEAD ||
	    P->state == PS_IDLE)
		return;

	P->status.pr_flttrace = *set;
	P->flags |= SETFAULT;

	if (P->state == PS_RUN)
		Psync(P);
}

/*
 * Set action on specified system call entry.
 */
int
Psysentry(struct ps_prochandle *P, int which, int stop)
{
	return (Psetaction(P, &P->status.pr_sysentry, sizeof (sysset_t),
	    SETENTRY, PRMAXSYS, which, stop));
}

/*
 * Set all system call entry tracing flags.
 */
void
Psetsysentry(struct ps_prochandle *P, const sysset_t *set)
{
	if (P->state == PS_DEAD || P->state == PS_UNDEAD ||
	    P->state == PS_IDLE)
		return;

	P->status.pr_sysentry = *set;
	P->flags |= SETENTRY;

	if (P->state == PS_RUN)
		Psync(P);
}

/*
 * Set action on specified system call exit.
 */
int
Psysexit(struct ps_prochandle *P, int which, int stop)
{
	return (Psetaction(P, &P->status.pr_sysexit, sizeof (sysset_t),
	    SETEXIT, PRMAXSYS, which, stop));
}

/*
 * Set all system call exit tracing flags.
 */
void
Psetsysexit(struct ps_prochandle *P, const sysset_t *set)
{
	if (P->state == PS_DEAD || P->state == PS_UNDEAD ||
	    P->state == PS_IDLE)
		return;

	P->status.pr_sysexit = *set;
	P->flags |= SETEXIT;

	if (P->state == PS_RUN)
		Psync(P);
}

/*
 * Utility function to read the contents of a file that contains a
 * prheader_t at the start (/proc/pid/lstatus or /proc/pid/lpsinfo).
 * Returns a malloc()d buffer or NULL on failure.
 */
static prheader_t *
read_lfile(struct ps_prochandle *P, const char *lname)
{
	prheader_t *Lhp;
	char lpath[64];
	struct stat64 statb;
	int fd;
	size_t size;
	ssize_t rval;

	(void) snprintf(lpath, sizeof (lpath), "/proc/%d/%s",
	    (int)P->status.pr_pid, lname);
	if ((fd = open(lpath, O_RDONLY)) < 0 || fstat64(fd, &statb) != 0) {
		if (fd >= 0)
			(void) close(fd);
		return (NULL);
	}

	/*
	 * 'size' is just the initial guess at the buffer size.
	 * It will have to grow if the number of lwps increases
	 * while we are looking at the process.
	 * 'size' must be larger than the actual file size.
	 */
	size = statb.st_size + 32;

	for (;;) {
		if ((Lhp = malloc(size)) == NULL)
			break;
		if ((rval = pread(fd, Lhp, size, 0)) < 0 ||
		    rval <= sizeof (prheader_t)) {
			free(Lhp);
			Lhp = NULL;
			break;
		}
		if (rval < size)
			break;
		/* need a bigger buffer */
		free(Lhp);
		size *= 2;
	}

	(void) close(fd);
	return (Lhp);
}

/*
 * LWP iteration interface.
 */
int
Plwp_iter(struct ps_prochandle *P, proc_lwp_f *func, void *cd)
{
	prheader_t *Lhp;
	lwpstatus_t *Lsp;
	long nlwp;
	int rv;

	switch (P->state) {
	case PS_RUN:
		(void) Pstopstatus(P, PCNULL, 0);
		break;

	case PS_STOP:
		Psync(P);
		break;

	case PS_IDLE:
		errno = ENODATA;
		return (-1);
	}

	/*
	 * For either live processes or cores, the single LWP case is easy:
	 * the pstatus_t contains the lwpstatus_t for the only LWP.
	 */
	if (P->status.pr_nlwp <= 1)
		return (func(cd, &P->status.pr_lwp));

	/*
	 * For the core file multi-LWP case, we just iterate through the
	 * list of LWP structs we read in from the core file.
	 */
	if (P->state == PS_DEAD) {
		lwp_info_t *lwp = list_prev(&P->core->core_lwp_head);
		uint_t i;

		for (i = 0; i < P->core->core_nlwp; i++, lwp = list_prev(lwp)) {
			if (lwp->lwp_psinfo.pr_sname != 'Z' &&
			    (rv = func(cd, &lwp->lwp_status)) != 0)
				break;
		}

		return (rv);
	}

	/*
	 * For the live process multi-LWP case, we have to work a little
	 * harder: the /proc/pid/lstatus file has the array of LWP structs.
	 */
	if ((Lhp = read_lfile(P, "lstatus")) == NULL)
		return (-1);

	for (nlwp = Lhp->pr_nent, Lsp = (lwpstatus_t *)(uintptr_t)(Lhp + 1);
	    nlwp > 0;
	    nlwp--, Lsp = (lwpstatus_t *)((uintptr_t)Lsp + Lhp->pr_entsize)) {
		if ((rv = func(cd, Lsp)) != 0)
			break;
	}

	free(Lhp);
	return (rv);
}

/*
 * Extended LWP iteration interface.
 * Iterate over all LWPs, active and zombie.
 */
int
Plwp_iter_all(struct ps_prochandle *P, proc_lwp_all_f *func, void *cd)
{
	prheader_t *Lhp = NULL;
	lwpstatus_t *Lsp;
	lwpstatus_t *sp;
	prheader_t *Lphp = NULL;
	lwpsinfo_t *Lpsp;
	long nstat;
	long ninfo;
	int rv;

retry:
	if (Lhp != NULL)
		free(Lhp);
	if (Lphp != NULL)
		free(Lphp);
	if (P->state == PS_RUN)
		(void) Pstopstatus(P, PCNULL, 0);
	(void) Ppsinfo(P);

	if (P->state == PS_STOP)
		Psync(P);

	/*
	 * For either live processes or cores, the single LWP case is easy:
	 * the pstatus_t contains the lwpstatus_t for the only LWP and
	 * the psinfo_t contains the lwpsinfo_t for the only LWP.
	 */
	if (P->status.pr_nlwp + P->status.pr_nzomb <= 1)
		return (func(cd, &P->status.pr_lwp, &P->psinfo.pr_lwp));

	/*
	 * For the core file multi-LWP case, we just iterate through the
	 * list of LWP structs we read in from the core file.
	 */
	if (P->state == PS_DEAD) {
		lwp_info_t *lwp = list_prev(&P->core->core_lwp_head);
		uint_t i;

		for (i = 0; i < P->core->core_nlwp; i++, lwp = list_prev(lwp)) {
			sp = (lwp->lwp_psinfo.pr_sname == 'Z')? NULL :
				&lwp->lwp_status;
			if ((rv = func(cd, sp, &lwp->lwp_psinfo)) != 0