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

	if (P->core->core_priv != NULL) {
		size = MIN(P->core->core_priv_size, size);
		(void) memcpy(pprv, P->core->core_priv, size);
		return (size);
	}
	errno = ENODATA;
	return (-1);
}

int
Psetpriv(struct ps_prochandle *P, prpriv_t *pprv)
{
	int rc;
	long *ctl;
	size_t sz;

	if (P->state == PS_DEAD) {
		errno = EBADF;
		return (-1);
	}

	sz = PRIV_PRPRIV_SIZE(pprv) + sizeof (long);

	sz = ((sz - 1) / sizeof (long) + 1) * sizeof (long);

	ctl = malloc(sz);
	if (ctl == NULL)
		return (-1);

	ctl[0] = PCSPRIV;

	(void) memcpy(&ctl[1], pprv, PRIV_PRPRIV_SIZE(pprv));

	if (write(P->ctlfd, ctl, sz) != sz)
		rc = -1;
	else
		rc = 0;

	free(ctl);

	return (rc);
}

void *
Pprivinfo(struct ps_prochandle *P)
{
	/* Use default from libc */
	if (P->state != PS_DEAD)
		return (NULL);

	return (P->core->core_privinfo);
}

/*
 * Ensure that all cached state is written to the process.
 * The cached state is the LWP's signal mask and registers
 * and the process's tracing flags.
 */
void
Psync(struct ps_prochandle *P)
{
	int ctlfd = (P->agentctlfd >= 0)? P->agentctlfd : P->ctlfd;
	long cmd[6];
	iovec_t iov[12];
	int n = 0;

	if (P->flags & SETHOLD) {
		cmd[0] = PCSHOLD;
		iov[n].iov_base = (caddr_t)&cmd[0];
		iov[n++].iov_len = sizeof (long);
		iov[n].iov_base = (caddr_t)&P->status.pr_lwp.pr_lwphold;
		iov[n++].iov_len = sizeof (P->status.pr_lwp.pr_lwphold);
	}
	if (P->flags & SETREGS) {
		cmd[1] = PCSREG;
#ifdef __i386
		/* XX64 we should probably restore REG_GS after this */
		if (ctlfd == P->agentctlfd)
			P->status.pr_lwp.pr_reg[GS] = 0;
#elif defined(__amd64)
		/* XX64 */
#endif
		iov[n].iov_base = (caddr_t)&cmd[1];
		iov[n++].iov_len = sizeof (long);
		iov[n].iov_base = (caddr_t)&P->status.pr_lwp.pr_reg[0];
		iov[n++].iov_len = sizeof (P->status.pr_lwp.pr_reg);
	}
	if (P->flags & SETSIG) {
		cmd[2] = PCSTRACE;
		iov[n].iov_base = (caddr_t)&cmd[2];
		iov[n++].iov_len = sizeof (long);
		iov[n].iov_base = (caddr_t)&P->status.pr_sigtrace;
		iov[n++].iov_len = sizeof (P->status.pr_sigtrace);
	}
	if (P->flags & SETFAULT) {
		cmd[3] = PCSFAULT;
		iov[n].iov_base = (caddr_t)&cmd[3];
		iov[n++].iov_len = sizeof (long);
		iov[n].iov_base = (caddr_t)&P->status.pr_flttrace;
		iov[n++].iov_len = sizeof (P->status.pr_flttrace);
	}
	if (P->flags & SETENTRY) {
		cmd[4] = PCSENTRY;
		iov[n].iov_base = (caddr_t)&cmd[4];
		iov[n++].iov_len = sizeof (long);
		iov[n].iov_base = (caddr_t)&P->status.pr_sysentry;
		iov[n++].iov_len = sizeof (P->status.pr_sysentry);
	}
	if (P->flags & SETEXIT) {
		cmd[5] = PCSEXIT;
		iov[n].iov_base = (caddr_t)&cmd[5];
		iov[n++].iov_len = sizeof (long);
		iov[n].iov_base = (caddr_t)&P->status.pr_sysexit;
		iov[n++].iov_len = sizeof (P->status.pr_sysexit);
	}

	if (n == 0 || writev(ctlfd, iov, n) < 0)
		return;		/* nothing to do or write failed */

	P->flags &= ~(SETSIG|SETFAULT|SETENTRY|SETEXIT|SETHOLD|SETREGS);
}

/*
 * Reopen the /proc file (after PS_LOST).
 */
int
Preopen(struct ps_prochandle *P)
{
	int fd;
	char procname[100];
	char *fname;

	if (P->state == PS_DEAD || P->state == PS_IDLE)
		return (0);

	if (P->agentcnt > 0) {
		P->agentcnt = 1;
		Pdestroy_agent(P);
	}

	(void) sprintf(procname, "/proc/%d/", (int)P->pid);
	fname = procname + strlen(procname);

	(void) strcpy(fname, "as");
	if ((fd = open(procname, O_RDWR)) < 0 ||
	    close(P->asfd) < 0 ||
	    (fd = dupfd(fd, P->asfd)) != P->asfd) {
		dprintf("Preopen: failed to open %s: %s\n",
		    procname, strerror(errno));
		if (fd >= 0)
			(void) close(fd);
		return (-1);
	}
	P->asfd = fd;

	(void) strcpy(fname, "status");
	if ((fd = open(procname, O_RDONLY)) < 0 ||
	    close(P->statfd) < 0 ||
	    (fd = dupfd(fd, P->statfd)) != P->statfd) {
		dprintf("Preopen: failed to open %s: %s\n",
		    procname, strerror(errno));
		if (fd >= 0)
			(void) close(fd);
		return (-1);
	}
	P->statfd = fd;

	(void) strcpy(fname, "ctl");
	if ((fd = open(procname, O_WRONLY)) < 0 ||
	    close(P->ctlfd) < 0 ||
	    (fd = dupfd(fd, P->ctlfd)) != P->ctlfd) {
		dprintf("Preopen: failed to open %s: %s\n",
		    procname, strerror(errno));
		if (fd >= 0)
			(void) close(fd);
		return (-1);
	}
	P->ctlfd = fd;

	/*
	 * Set the state to PS_RUN and wait for the process to stop so that
	 * we re-read the status from the new P->statfd.  If this fails, Pwait
	 * will reset the state to PS_LOST and we fail the reopen.  Before
	 * returning, we also forge a bit of P->status to allow the debugger to
	 * see that we are PS_LOST following a successful exec.
	 */
	P->state = PS_RUN;
	if (Pwait(P, 0) == -1) {
#ifdef _ILP32
		if (errno == EOVERFLOW)
			P->status.pr_dmodel = PR_MODEL_LP64;
#endif
		P->status.pr_lwp.pr_why = PR_SYSEXIT;
		P->status.pr_lwp.pr_what = SYS_execve;
		P->status.pr_lwp.pr_errno = 0;
		return (-1);
	}

	/*
	 * The process should be stopped on exec (REQUESTED)
	 * or else should be stopped on exit from exec() (SYSEXIT)
	 */
	if (P->state == PS_STOP &&
	    (P->status.pr_lwp.pr_why == PR_REQUESTED ||
	    (P->status.pr_lwp.pr_why == PR_SYSEXIT &&
	    (P->status.pr_lwp.pr_what == SYS_exec ||
	    P->status.pr_lwp.pr_what == SYS_execve)))) {
		/* fake up stop-on-exit-from-execve */
		if (P->status.pr_lwp.pr_why == PR_REQUESTED) {
			P->status.pr_lwp.pr_why = PR_SYSEXIT;
			P->status.pr_lwp.pr_what = SYS_execve;
			P->status.pr_lwp.pr_errno = 0;
		}
	} else {
		dprintf("Preopen: expected REQUESTED or "
		    "SYSEXIT(SYS_execve) stop\n");
	}

	return (0);
}

/*
 * Define all settable flags other than the microstate accounting flags.
 */
#define	ALL_SETTABLE_FLAGS (PR_FORK|PR_RLC|PR_KLC|PR_ASYNC|PR_BPTADJ|PR_PTRACE)

/*
 * Restore /proc tracing flags to their original values
 * in preparation for releasing the process.
 * Also called by Pcreate() to clear all tracing flags.
 */
static void
restore_tracing_flags(struct ps_prochandle *P)
{
	long flags;
	long cmd[4];
	iovec_t iov[8];

	if (P->flags & CREATED) {
		/* we created this process; clear all tracing flags */
		premptyset(&P->status.pr_sigtrace);
		premptyset(&P->status.pr_flttrace);
		premptyset(&P->status.pr_sysentry);
		premptyset(&P->status.pr_sysexit);
		if ((P->status.pr_flags & ALL_SETTABLE_FLAGS) != 0)
			(void) Punsetflags(P, ALL_SETTABLE_FLAGS);
	} else {
		/* we grabbed the process; restore its tracing flags */
		P->status.pr_sigtrace = P->orig_status.pr_sigtrace;
		P->status.pr_flttrace = P->orig_status.pr_flttrace;
		P->status.pr_sysentry = P->orig_status.pr_sysentry;
		P->status.pr_sysexit  = P->orig_status.pr_sysexit;
		if ((P->status.pr_flags & ALL_SETTABLE_FLAGS) !=
		    (flags = (P->orig_status.pr_flags & ALL_SETTABLE_FLAGS))) {
			(void) Punsetflags(P, ALL_SETTABLE_FLAGS);
			if (flags)
				(void) Psetflags(P, flags);
		}
	}

	cmd[0] = PCSTRACE;
	iov[0].iov_base = (caddr_t)&cmd[0];
	iov[0].iov_len = sizeof (long);
	iov[1].iov_base = (caddr_t)&P->status.pr_sigtrace;
	iov[1].iov_len = sizeof (P->status.pr_sigtrace);

	cmd[1] = PCSFAULT;
	iov[2].iov_base = (caddr_t)&cmd[1];
	iov[2].iov_len = sizeof (long);
	iov[3].iov_base = (caddr_t)&P->status.pr_flttrace;
	iov[3].iov_len = sizeof (P->status.pr_flttrace);

	cmd[2] = PCSENTRY;
	iov[4].iov_base = (caddr_t)&cmd[2];
	iov[4].iov_len = sizeof (long);
	iov[5].iov_base = (caddr_t)&P->status.pr_sysentry;
	iov[5].iov_len = sizeof (P->status.pr_sysentry);

	cmd[3] = PCSEXIT;
	iov[6].iov_base = (caddr_t)&cmd[3];
	iov[6].iov_len = sizeof (long);
	iov[7].iov_base = (caddr_t)&P->status.pr_sysexit;
	iov[7].iov_len = sizeof (P->status.pr_sysexit);

	(void) writev(P->ctlfd, iov, 8);

	P->flags &= ~(SETSIG|SETFAULT|SETENTRY|SETEXIT);
}

/*
 * Release the process.  Frees the process control structure.
 * flags:
 *	PRELEASE_CLEAR	Clear all tracing flags.
 *	PRELEASE_RETAIN	Retain current tracing flags.
 *	PRELEASE_HANG	Leave the process stopped and abandoned.
 *	PRELEASE_KILL	Terminate the process with SIGKILL.
 */
void
Prelease(struct ps_prochandle *P, int flags)
{
	if (P->state == PS_DEAD) {
		dprintf("Prelease: releasing handle %p PS_DEAD of pid %d\n",
		    (void *)P, (int)P->pid);
		Pfree(P);
		return;
	}

	if (P->state == PS_IDLE) {
		file_info_t *fptr = list_next(&P->file_head);
		dprintf("Prelease: releasing handle %p PS_IDLE of file %s\n",
		    (void *)P, fptr->file_pname);
		Pfree(P);
		return;
	}

	dprintf("Prelease: releasing handle %p pid %d\n",
	    (void *)P, (int)P->pid);

	if (P->ctlfd == -1) {
		Pfree(P);
		return;
	}

	if (P->agentcnt > 0) {
		P->agentcnt = 1;
		Pdestroy_agent(P);
	}

	/*
	 * Attempt to stop the process.
	 */
	P->state = PS_RUN;
	(void) Pstop(P, 1000);

	if (flags & PRELEASE_KILL) {
		if (P->state == PS_STOP)
			(void) Psetrun(P, SIGKILL, 0);
		(void) kill(P->pid, SIGKILL);
		Pfree(P);
		return;
	}

	/*
	 * If we lost control, all we can do now is close the files.
	 * In this case, the last close sets the process running.
	 */
	if (P->state != PS_STOP &&
	    (P->status.pr_lwp.pr_flags & (PR_ISTOP|PR_DSTOP)) == 0) {
		Pfree(P);
		return;
	}

	/*
	 * We didn't lose control; we do more.
	 */
	Psync(P);

	if (flags & PRELEASE_CLEAR)
		P->flags |= CREATED;

	if (!(flags & PRELEASE_RETAIN))
		restore_tracing_flags(P);

	if (flags & PRELEASE_HANG) {
		/* Leave the process stopped and abandoned */
		(void) Punsetflags(P, PR_RLC|PR_KLC);
		Pfree(P);
		return;
	}

	/*
	 * Set the process running if we created it or if it was
	 * not originally stopped or directed to stop via /proc
	 * or if we were given the PRELEASE_CLEAR flag.
	 */
	if ((P->flags & CREATED) ||
	    (P->orig_status.pr_lwp.pr_flags & (PR_ISTOP|PR_DSTOP)) == 0) {
		(void) Psetflags(P, PR_RLC);
		/*
		 * We do this repeatedly because the process may have
		 * more than one LWP stopped on an event of interest.
		 * This makes sure all of them are set running.
		 */
		do {
			if (Psetrun(P, 0, 0) == -1 && errno == EBUSY)
				break; /* Agent LWP may be stuck */
		} while (Pstopstatus(P, PCNULL, 0) == 0 &&
		    P->status.pr_lwp.pr_flags & (PR_ISTOP|PR_DSTOP));

		if (P->status.pr_lwp.pr_flags & (PR_ISTOP|PR_DSTOP))
			dprintf("Prelease: failed to set process running\n");
	}

	Pfree(P);
}

/* debugging */
void
prldump(const char *caller, lwpstatus_t *lsp)
{
	char name[32];
	uint32_t bits;

	switch (lsp->pr_why) {
	case PR_REQUESTED:
		dprintf("%s: REQUESTED\n", caller);
		break;
	case PR_SIGNALLED:
		dprintf("%s: SIGNALLED %s\n", caller,
			proc_signame(lsp->pr_what, name, sizeof (name)));
		break;
	case PR_FAULTED:
		dprintf("%s: FAULTED %s\n", caller,
			proc_fltname(lsp->pr_what, name, sizeof (name)));
		break;
	case PR_SYSENTRY:
		dprintf("%s: SYSENTRY %s\n", caller,
			proc_sysname(lsp->pr_what, name, sizeof (name)));
		break;
	case PR_SYSEXIT:
		dprintf("%s: SYSEXIT %s\n", caller,
			proc_sysname(lsp->pr_what, name, sizeof (name)));
		break;
	case PR_JOBCONTROL:
		dprintf("%s: JOBCONTROL %s\n", caller,
			proc_signame(lsp->pr_what, name, sizeof (name)));
		break;
	case PR_SUSPENDED:
		dprintf("%s: SUSPENDED\n", caller);
		break;
	default:
		dprintf("%s: Unknown\n", caller);
		break;
	}

	if (lsp->pr_cursig)
		dprintf("%s: p_cursig  = %d\n", caller, lsp->pr_cursig);

	bits = *((uint32_t *)&lsp->pr_lwppend);
	if (bits)
		dprintf("%s: pr_lwppend = 0x%.8X\n", caller, bits);
}

/* debugging */
static void
prdump(struct ps_prochandle *P)
{
	uint32_t bits;

	prldump("Pstopstatus", &P->status.pr_lwp);

	bits = *((uint32_t *)&P->status.pr_sigpend);
	if (bits)
		dprintf("Pstopstatus: pr_sigpend = 0x%.8X\n", bits);
}

/*
 * Wait for the specified process to stop or terminate.
 * Or, just get the current status (PCNULL).
 * Or, direct it to stop and get the current status (PCDSTOP).
 * If the agent LWP exists, do these things to the agent,
 * else do these things to the process as a whole.
 */
int
Pstopstatus(struct ps_prochandle *P,
	long request,		/* PCNULL, PCDSTOP, PCSTOP, PCWSTOP */
	uint_t msec)		/* if non-zero, timeout in milliseconds */
{
	int ctlfd = (P->agentctlfd >= 0)? P->agentctlfd : P->ctlfd;
	long ctl[3];
	ssize_t rc;
	int err;
	int old_state = P->state;

	switch (P->state) {
	case PS_RUN:
		break;
	case PS_STOP:
		if (request != PCNULL && request != PCDSTOP)
			return (0);
		break;
	case PS_LOST:
		if (request != PCNULL) {
			errno = EAGAIN;
			return (-1);
		}
		break;
	case PS_UNDEAD:
	case PS_DEAD:
	case PS_IDLE:
		if (request != PCNULL) {
			errno = ENOENT;
			return (-1);
		}
		break;
	default:	/* corrupted state */
		dprintf("Pstopstatus: corrupted state: %d\n", P->state);
		errno = EINVAL;
		return (-1);
	}

	ctl[0] = PCDSTOP;
	ctl[1] = PCTWSTOP;
	ctl[2] = (long)msec;
	rc = 0;
	switch (request) {
	case PCSTOP:
		rc = write(ctlfd, &ctl[0], 3*sizeof (long));
		break;
	case PCWSTOP:
		rc = write(ctlfd, &ctl[1], 2*sizeof (long));
		break;
	case PCDSTOP:
		rc = write(ctlfd, &ctl[0], 1*sizeof (long));
		break;
	case PCNULL:
		if (P->state == PS_DEAD || P->state == PS_IDLE)
			return (0);
		break;
	default:	/* programming error */
		errno = EINVAL;
		return (-1);
	}
	err = (rc < 0)? errno : 0;
	Psync(P);

	if (P->agentstatfd < 0) {
		if (pread(P->statfd, &P->status,
		    sizeof (P->status), (off_t)0) < 0)
			err = errno;
	} else {
		if (pread(P->agentstatfd, &P->status.pr_lwp,
		    sizeof (P->status.pr_lwp), (off_t)0) < 0)
			err = errno;
		P->status.pr_flags = P->status.pr_lwp.pr_flags;
	}

	if (err) {
		switch (err) {
		case EINTR:		/* user typed ctl-C */
		case ERESTART:
			dprintf("Pstopstatus: EINTR\n");
			break;
		case EAGAIN:		/* we lost control of the the process */
		case EOVERFLOW:
			dprintf("Pstopstatus: PS_LOST, errno=%d\n", err);
			P->state = PS_LOST;
			break;
		default:		/* check for dead process */
			if (_libproc_debug) {
				const char *errstr;

				switch (request) {
				case PCNULL:
					errstr = "Pstopstatus PCNULL"; break;
				case PCSTOP:
					errstr = "Pstopstatus PCSTOP"; break;
				case PCDSTOP: