xref: /illumos-gate/usr/src/lib/libc/i386/sys/ptrace.c (revision bbf21555)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * ptrace(2) interface built on top of proc(5).
29  */
30 
31 #pragma weak _ptrace = ptrace
32 
33 #include "lint.h"
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <unistd.h>
37 #include <memory.h>
38 #include <string.h>
39 #include <fcntl.h>
40 #include <errno.h>
41 #include <sys/types.h>
42 #include <sys/uio.h>
43 #include <signal.h>
44 #include <sys/siginfo.h>
45 #include <sys/fault.h>
46 #include <sys/syscall.h>
47 #include <procfs.h>
48 #include <sys/psw.h>
49 #include <sys/user.h>
50 /*
51  * mtlib.h must precede thread.h
52  */
53 #include <mtlib.h>
54 #include <thread.h>
55 #include <synch.h>
56 
57 static mutex_t pt_lock = DEFAULTMUTEX;
58 
59 #define	TRUE	1
60 #define	FALSE	0
61 
62 /*
63  * All my children...
64  */
65 typedef struct cstatus {
66 	struct cstatus	*next;		/* linked list			*/
67 	pid_t		pid;		/* process-id			*/
68 	int		asfd;		/* /proc/<pid>/as		*/
69 	int		ctlfd;		/* /proc/<pid>/ctl		*/
70 	int		statusfd;	/* /proc/<pid>/status		*/
71 	int		flags;		/* see below			*/
72 	pstatus_t	pstatus;	/* from /proc/<pid>/status	*/
73 	user_t		user;		/* manufactured u-block		*/
74 } cstatus_t;
75 
76 /* flags */
77 #define	CS_SETREGS	0x01		/* set registers on run		*/
78 #define	CS_PSARGS	0x02		/* u_psargs[] has been fetched	*/
79 #define	CS_SIGNAL	0x04		/* u_signal[] has been fetched	*/
80 
81 #define	NULLCP	((cstatus_t *)0)
82 
83 static cstatus_t *childp = NULLCP;
84 
85 /* fake u-block offsets */
86 #define	UP		((user_t *)NULL)
87 #define	U_REG		((int)(&UP->u_reg[0]))
88 #define	U_AR0		((int)(&UP->u_ar0))
89 #define	U_PSARGS	((int)(&UP->u_psargs[0]))
90 #define	U_SIGNAL	((int)(&UP->u_signal[0]))
91 #define	U_CODE		((int)(&UP->u_code))
92 #define	U_ADDR		((int)(&UP->u_addr))
93 #define	U_END		((int)sizeof (user_t))
94 #define	REGADDR		0xffff0000	/* arbitrary kernel address for u_ar0 */
95 
96 /* external routines defined in this module */
97 extern	int	ptrace(int, pid_t, int, int);
98 /* static routines defined in this module */
99 static	cstatus_t *FindProc(pid_t);
100 static	void	CheckAllProcs(void);
101 static	int	Dupfd(int, int);
102 static	void	MakeProcName(char *, pid_t);
103 static	int	OpenProc(cstatus_t *);
104 static	void	CloseProc(cstatus_t *);
105 static	cstatus_t *GrabProc(pid_t);
106 static	void	ReleaseProc(cstatus_t *);
107 static	int	ProcUpdate(cstatus_t *);
108 static	void	MakeUser(cstatus_t *);
109 static	void	GetPsargs(cstatus_t *);
110 static	void	GetSignal(cstatus_t *);
111 
112 #if PTRACE_DEBUG
113 /* for debugging */
114 static char *
map(int request)115 map(int request)
116 {
117 	static char name[20];
118 
119 	switch (request) {
120 	case 0:	return ("PTRACE_TRACEME");
121 	case 1:	return ("PTRACE_PEEKTEXT");
122 	case 2:	return ("PTRACE_PEEKDATA");
123 	case 3:	return ("PTRACE_PEEKUSER");
124 	case 4:	return ("PTRACE_POKETEXT");
125 	case 5:	return ("PTRACE_POKEDATA");
126 	case 6:	return ("PTRACE_POKEUSER");
127 	case 7:	return ("PTRACE_CONT");
128 	case 8:	return ("PTRACE_KILL");
129 	case 9:	return ("PTRACE_SINGLESTEP");
130 	}
131 	(void) sprintf(name, "%d", request);
132 	return (name);
133 }
134 #endif
135 
136 int
ptrace(int request,pid_t pid,int addr,int data)137 ptrace(int request, pid_t pid, int addr, int data)
138 {
139 	pstatus_t *ps;
140 	cstatus_t *cp;
141 	unsigned xaddr;
142 	struct {
143 		long cmd;
144 		union {
145 			long flags;
146 			sigset_t signals;
147 			fltset_t faults;
148 			sysset_t syscalls;
149 			siginfo_t siginfo;
150 		} arg;
151 	} ctl;
152 
153 #if PTRACE_DEBUG
154 	fprintf(stderr, " ptrace(%s, 0x%X, 0x%X, 0x%X)\n",
155 	    map(request), pid, addr, data);
156 #endif
157 
158 	(void) mutex_lock(&pt_lock);
159 
160 	if (request == 0) {	/* PTRACE_TRACEME, executed by traced process */
161 		/*
162 		 * Set stop-on-all-signals and nothing else.
163 		 * Turn off inherit-on-fork flag (grandchildren run away).
164 		 * Set ptrace-compatible flag.
165 		 */
166 		char procname[64];	/* /proc/<pid>/ctl */
167 		int fd;
168 
169 		MakeProcName(procname, getpid());
170 		(void) strcat(procname, "/ctl");
171 		if ((fd = open(procname, O_WRONLY, 0)) < 0)
172 			exit(255);
173 		ctl.cmd = PCSTRACE;
174 		prfillset(&ctl.arg.signals);
175 		if (write(fd, (char *)&ctl, sizeof (long)+sizeof (sigset_t))
176 		    != sizeof (long)+sizeof (sigset_t))
177 			exit(255);
178 		ctl.cmd = PCSFAULT;
179 		premptyset(&ctl.arg.faults);
180 		if (write(fd, (char *)&ctl, sizeof (long)+sizeof (fltset_t))
181 		    != sizeof (long)+sizeof (fltset_t))
182 			exit(255);
183 		ctl.cmd = PCSENTRY;
184 		premptyset(&ctl.arg.syscalls);
185 		if (write(fd, (char *)&ctl, sizeof (long)+sizeof (sysset_t))
186 		    != sizeof (long)+sizeof (sysset_t))
187 			exit(255);
188 		ctl.cmd = PCSEXIT;
189 		premptyset(&ctl.arg.syscalls);
190 		if (write(fd, (char *)&ctl, sizeof (long)+sizeof (sysset_t))
191 		    != sizeof (long)+sizeof (sysset_t))
192 			exit(255);
193 		ctl.cmd = PCUNSET;
194 		ctl.arg.flags = PR_FORK;
195 		if (write(fd, (char *)&ctl, sizeof (long)+sizeof (long))
196 		    != sizeof (long)+sizeof (long))
197 			exit(255);
198 		ctl.cmd = PCSET;
199 		ctl.arg.flags = PR_PTRACE;
200 		if (write(fd, (char *)&ctl, sizeof (long)+sizeof (long))
201 		    != sizeof (long)+sizeof (long))
202 			exit(255);
203 		if (close(fd) != 0)
204 			exit(255);
205 
206 		(void) mutex_unlock(&pt_lock);
207 		return (0);
208 	}
209 
210 again:
211 	errno = 0;
212 
213 	/* find the cstatus structure corresponding to pid */
214 	if ((cp = GrabProc(pid)) == NULLCP)
215 		goto esrch;
216 
217 	ps = &cp->pstatus;
218 	if (!(ps->pr_flags & PR_ISTOP)) {
219 		if (ProcUpdate(cp) != 0) {
220 			ReleaseProc(cp);
221 			goto esrch;
222 		}
223 		if (!(ps->pr_flags & PR_ISTOP))
224 			goto esrch;
225 	}
226 
227 	/*
228 	 * Process the request.
229 	 */
230 	errno = 0;
231 	switch (request) {
232 	case 1:		/* PTRACE_PEEKTEXT */
233 	case 2:		/* PTRACE_PEEKDATA */
234 		if (addr & 03)
235 			goto eio;
236 		if (pread(cp->asfd, (char *)&data, sizeof (data), (off_t)addr)
237 		    == sizeof (data)) {
238 			(void) mutex_unlock(&pt_lock);
239 			return (data);
240 		}
241 		goto eio;
242 
243 	case 3:		/* PTRACE_PEEKUSER */
244 		if (addr & 03)
245 			goto eio;
246 		xaddr = addr;
247 		if (xaddr >= REGADDR && xaddr < REGADDR+sizeof (gregset_t))
248 			xaddr -= REGADDR-U_REG;
249 		if (xaddr >= U_PSARGS && xaddr < U_PSARGS+sizeof (UP->u_psargs))
250 			GetPsargs(cp);
251 		if (xaddr >= U_SIGNAL && xaddr < U_SIGNAL+sizeof (UP->u_signal))
252 			GetSignal(cp);
253 		if ((int)xaddr >= 0 && xaddr < U_END) {
254 			/* LINTED pointer alignment */
255 			data = *((int *)((caddr_t)(&cp->user) + xaddr));
256 			(void) mutex_unlock(&pt_lock);
257 			return (data);
258 		}
259 		goto eio;
260 
261 	case 4:		/* PTRACE_POKETEXT */
262 	case 5:		/* PTRACE_POKEDATA */
263 		if (addr & 03)
264 			goto eio;
265 		if (pwrite(cp->asfd, (char *)&data, sizeof (data), (off_t)addr)
266 		    == sizeof (data)) {
267 			(void) mutex_unlock(&pt_lock);
268 			return (data);
269 		}
270 		goto eio;
271 
272 	case 6:		/* PTRACE_POKEUSER */
273 		if (addr & 03)
274 			goto eio;
275 		xaddr = addr;
276 		if (xaddr >= REGADDR && xaddr < REGADDR+sizeof (gregset_t))
277 			xaddr -= REGADDR-U_REG;
278 		if ((int)xaddr >= U_REG && xaddr < U_REG+sizeof (gregset_t)) {
279 			int rx = (xaddr-U_REG)/sizeof (greg_t);
280 			if (rx == EFL)
281 				data = (cp->user.u_reg[EFL] & ~PSL_USERMASK) |
282 				    (data & PSL_USERMASK);
283 			cp->user.u_reg[rx] = data;
284 			cp->flags |= CS_SETREGS;
285 			(void) mutex_unlock(&pt_lock);
286 			return (data);
287 		}
288 		goto eio;
289 
290 	case 7:		/* PTRACE_CONT */
291 	case 9:		/* PTRACE_SINGLESTEP */
292 	{
293 		long runctl[3];
294 
295 		if (cp->flags & CS_SETREGS) {
296 			long cmd;
297 			iovec_t iov[2];
298 
299 			ps->pr_lwp.pr_reg[GS] = cp->user.u_reg[GS];
300 			ps->pr_lwp.pr_reg[FS] = cp->user.u_reg[FS];
301 			ps->pr_lwp.pr_reg[ES] = cp->user.u_reg[ES];
302 			ps->pr_lwp.pr_reg[DS] = cp->user.u_reg[DS];
303 			ps->pr_lwp.pr_reg[EDI] = cp->user.u_reg[EDI];
304 			ps->pr_lwp.pr_reg[ESI] = cp->user.u_reg[ESI];
305 			ps->pr_lwp.pr_reg[EBP] = cp->user.u_reg[EBP];
306 			ps->pr_lwp.pr_reg[ESP] = cp->user.u_reg[ESP];
307 			ps->pr_lwp.pr_reg[EBX] = cp->user.u_reg[EBX];
308 			ps->pr_lwp.pr_reg[EDX] = cp->user.u_reg[EDX];
309 			ps->pr_lwp.pr_reg[ECX] = cp->user.u_reg[ECX];
310 			ps->pr_lwp.pr_reg[EAX] = cp->user.u_reg[EAX];
311 			ps->pr_lwp.pr_reg[TRAPNO] = cp->user.u_reg[TRAPNO];
312 			ps->pr_lwp.pr_reg[ERR] = cp->user.u_reg[ERR];
313 			ps->pr_lwp.pr_reg[EIP] = cp->user.u_reg[EIP];
314 			ps->pr_lwp.pr_reg[CS] = cp->user.u_reg[CS];
315 			ps->pr_lwp.pr_reg[EFL] = cp->user.u_reg[EFL];
316 			ps->pr_lwp.pr_reg[UESP] = cp->user.u_reg[UESP];
317 			ps->pr_lwp.pr_reg[SS] = cp->user.u_reg[SS];
318 			cmd = PCSREG;
319 			iov[0].iov_base = (caddr_t)&cmd;
320 			iov[0].iov_len = sizeof (long);
321 			iov[1].iov_base = (caddr_t)&ps->pr_lwp.pr_reg[0];
322 			iov[1].iov_len = sizeof (ps->pr_lwp.pr_reg);
323 			if (writev(cp->ctlfd, iov, 2) < 0)
324 				goto tryagain;
325 		}
326 		if (addr != 1 &&	/* new virtual address */
327 		    addr != cp->user.u_reg[EIP]) {
328 			runctl[0] = PCSVADDR;
329 			runctl[1] = addr;
330 			if (write(cp->ctlfd, (char *)runctl, 2*sizeof (long))
331 			    != 2*sizeof (long))
332 				goto tryagain;
333 		}
334 		/* make data the current signal */
335 		if (data != 0 && data != ps->pr_lwp.pr_cursig) {
336 			(void) memset((char *)&ctl.arg.siginfo, 0,
337 			    sizeof (siginfo_t));
338 			ctl.arg.siginfo.si_signo = data;
339 			ctl.cmd = PCSSIG;
340 			if (write(cp->ctlfd, (char *)&ctl,
341 			    sizeof (long)+sizeof (siginfo_t))
342 			    != sizeof (long)+sizeof (siginfo_t))
343 				goto tryagain;
344 		}
345 		if (data == 0)
346 			runctl[0] = PCCSIG;
347 		else
348 			runctl[0] = PCNULL;
349 		runctl[1] = PCRUN;
350 		runctl[2] = (request == 9)? PRSTEP : 0;
351 		if (write(cp->ctlfd, (char *)runctl, 3*sizeof (long))
352 		    != 3*sizeof (long)) {
353 			if (errno == ENOENT) {
354 				/* current signal must have killed it */
355 				ReleaseProc(cp);
356 				(void) mutex_unlock(&pt_lock);
357 				return (data);
358 			}
359 			goto tryagain;
360 		}
361 		(void) memset((char *)ps, 0, sizeof (pstatus_t));
362 		cp->flags = 0;
363 		(void) mutex_unlock(&pt_lock);
364 		return (data);
365 	}
366 
367 	case 8:		/* PTRACE_KILL */
368 		/* overkill? */
369 		(void) memset((char *)&ctl.arg.siginfo, 0, sizeof (siginfo_t));
370 		ctl.arg.siginfo.si_signo = SIGKILL;
371 		ctl.cmd = PCSSIG;
372 		(void) write(cp->ctlfd, (char *)&ctl,
373 		    sizeof (long)+sizeof (siginfo_t));
374 		(void) kill(pid, SIGKILL);
375 		ReleaseProc(cp);
376 		(void) mutex_unlock(&pt_lock);
377 		return (0);
378 
379 	default:
380 		goto eio;
381 	}
382 
383 tryagain:
384 	if (errno == EAGAIN) {
385 		if (OpenProc(cp) == 0)
386 			goto again;
387 		ReleaseProc(cp);
388 	}
389 eio:
390 	errno = EIO;
391 	(void) mutex_unlock(&pt_lock);
392 	return (-1);
393 esrch:
394 	errno = ESRCH;
395 	(void) mutex_unlock(&pt_lock);
396 	return (-1);
397 }
398 
399 /*
400  * Find the cstatus structure corresponding to pid.
401  */
402 static cstatus_t *
FindProc(pid_t pid)403 FindProc(pid_t pid)
404 {
405 	cstatus_t *cp;
406 
407 	for (cp = childp; cp != NULLCP; cp = cp->next)
408 		if (cp->pid == pid)
409 			break;
410 
411 	return (cp);
412 }
413 
414 /*
415  * Check every proc for existence, release those that are gone.
416  * Be careful about the linked list; ReleaseProc() changes it.
417  */
418 static void
CheckAllProcs()419 CheckAllProcs()
420 {
421 	cstatus_t *cp = childp;
422 
423 	while (cp != NULLCP) {
424 		cstatus_t *next = cp->next;
425 
426 		if (ProcUpdate(cp) != 0)
427 			ReleaseProc(cp);
428 		cp = next;
429 	}
430 }
431 
432 /*
433  * Utility for OpenProc().
434  */
435 static int
Dupfd(int fd,int dfd)436 Dupfd(int fd, int dfd)
437 {
438 	/*
439 	 * Make sure fd not one of 0, 1, or 2 to avoid stdio interference.
440 	 * Also, if dfd is greater than 2, dup fd to be exactly dfd.
441 	 */
442 	if (dfd > 2 || (0 <= fd && fd <= 2)) {
443 		if (dfd > 2 && fd != dfd)
444 			(void) close(dfd);
445 		else
446 			dfd = 3;
447 		if (fd != dfd) {
448 			dfd = fcntl(fd, F_DUPFD, (intptr_t)dfd);
449 			(void) close(fd);
450 			fd = dfd;
451 		}
452 	}
453 	/*
454 	 * Mark filedescriptor close-on-exec.
455 	 * Should also be close-on-return-from-fork-in-child.
456 	 */
457 	(void) fcntl(fd, F_SETFD, (intptr_t)1);
458 	return (fd);
459 }
460 
461 /*
462  * Construct the /proc directory name:  "/proc/<pid>"
463  * The name buffer passed by the caller must be large enough.
464  */
465 static void
MakeProcName(char * procname,pid_t pid)466 MakeProcName(char *procname, pid_t pid)
467 {
468 	(void) sprintf(procname, "/proc/%ld", pid);
469 }
470 
471 /*
472  * Open/reopen the /proc/<pid> files.
473  */
474 static int
OpenProc(cstatus_t * cp)475 OpenProc(cstatus_t *cp)
476 {
477 	char procname[64];		/* /proc/nnnnn/fname */
478 	char *fname;
479 	int fd;
480 	int omode;
481 
482 	MakeProcName(procname, cp->pid);
483 	fname = procname + strlen(procname);
484 
485 	/*
486 	 * Use exclusive-open only if this is the first open.
487 	 */
488 	omode = (cp->asfd > 0)? O_RDWR : (O_RDWR|O_EXCL);
489 	(void) strcpy(fname, "/as");
490 	if ((fd = open(procname, omode, 0)) < 0 ||
491 	    (cp->asfd = Dupfd(fd, cp->asfd)) < 0)
492 		goto err;
493 
494 	(void) strcpy(fname, "/ctl");
495 	if ((fd = open(procname, O_WRONLY, 0)) < 0 ||
496 	    (cp->ctlfd = Dupfd(fd, cp->ctlfd)) < 0)
497 		goto err;
498 
499 	(void) strcpy(fname, "/status");
500 	if ((fd = open(procname, O_RDONLY, 0)) < 0 ||
501 	    (cp->statusfd = Dupfd(fd, cp->statusfd)) < 0)
502 		goto err;
503 
504 	return (0);
505 
506 err:
507 	CloseProc(cp);
508 	return (-1);
509 }
510 
511 /*
512  * Close the /proc/<pid> files.
513  */
514 static void
CloseProc(cstatus_t * cp)515 CloseProc(cstatus_t *cp)
516 {
517 	if (cp->asfd > 0)
518 		(void) close(cp->asfd);
519 	if (cp->ctlfd > 0)
520 		(void) close(cp->ctlfd);
521 	if (cp->statusfd > 0)
522 		(void) close(cp->statusfd);
523 	cp->asfd = 0;
524 	cp->ctlfd = 0;
525 	cp->statusfd = 0;
526 }
527 
528 /*
529  * Take control of a child process.
530  */
531 static cstatus_t *
GrabProc(pid_t pid)532 GrabProc(pid_t pid)
533 {
534 	cstatus_t *cp;
535 	long ctl[2];
536 	pid_t ppid;
537 
538 	if (pid <= 0)
539 		return (NULLCP);
540 
541 	if ((cp = FindProc(pid)) != NULLCP)	/* already grabbed */
542 		return (cp);
543 
544 	CheckAllProcs();	/* clean up before grabbing new process */
545 
546 	cp = (cstatus_t *)malloc(sizeof (cstatus_t));
547 	if (cp == NULLCP)
548 		return (NULLCP);
549 	(void) memset((char *)cp, 0, sizeof (cstatus_t));
550 	cp->pid = pid;
551 
552 	ppid = getpid();
553 	while (OpenProc(cp) == 0) {
554 		ctl[0] = PCSET;
555 		ctl[1] = PR_RLC;
556 		errno = 0;
557 
558 		if (pread(cp->statusfd, (char *)&cp->pstatus,
559 		    sizeof (cp->pstatus), (off_t)0) == sizeof (cp->pstatus) &&
560 		    cp->pstatus.pr_ppid == ppid &&
561 		    (cp->pstatus.pr_flags & PR_PTRACE) &&
562 		    write(cp->ctlfd, (char *)ctl, 2*sizeof (long))
563 		    == 2*sizeof (long)) {
564 			cp->next = childp;
565 			childp = cp;
566 			MakeUser(cp);
567 			return (cp);
568 		}
569 
570 		if (errno != EAGAIN)
571 			break;
572 	}
573 
574 	free((char *)cp);
575 	return (NULLCP);
576 }
577 
578 /*
579  * Close the /proc/<pid> file, if open.
580  * Deallocate the memory used by the cstatus_t structure.
581  */
582 static void
ReleaseProc(cstatus_t * cp)583 ReleaseProc(cstatus_t *cp)
584 {
585 	CloseProc(cp);
586 
587 	if (childp == cp)
588 		childp = cp->next;
589 	else {
590 		cstatus_t *pcp;
591 
592 		for (pcp = childp; pcp != NULLCP; pcp = pcp->next) {
593 			if (pcp->next == cp) {
594 				pcp->next = cp->next;
595 				break;
596 			}
597 		}
598 	}
599 
600 	free((char *)cp);
601 }
602 
603 /*
604  * Update process information from /proc.
605  * Return 0 on success, -1 on failure.
606  */
607 static int
ProcUpdate(cstatus_t * cp)608 ProcUpdate(cstatus_t *cp)
609 {
610 	pstatus_t *ps = &cp->pstatus;
611 
612 	if (cp->flags & CS_SETREGS) {
613 		long cmd;
614 		iovec_t iov[2];
615 
616 		ps->pr_lwp.pr_reg[GS]   = cp->user.u_reg[GS];
617 		ps->pr_lwp.pr_reg[FS]   = cp->user.u_reg[FS];
618 		ps->pr_lwp.pr_reg[ES]   = cp->user.u_reg[ES];
619 		ps->pr_lwp.pr_reg[DS]   = cp->user.u_reg[DS];
620 		ps->pr_lwp.pr_reg[EDI]  = cp->user.u_reg[EDI];
621 		ps->pr_lwp.pr_reg[ESI]  = cp->user.u_reg[ESI];
622 		ps->pr_lwp.pr_reg[EBP]  = cp->user.u_reg[EBP];
623 		ps->pr_lwp.pr_reg[ESP]  = cp->user.u_reg[ESP];
624 		ps->pr_lwp.pr_reg[EBX]  = cp->user.u_reg[EBX];
625 		ps->pr_lwp.pr_reg[EDX]  = cp->user.u_reg[EDX];
626 		ps->pr_lwp.pr_reg[ECX]  = cp->user.u_reg[ECX];
627 		ps->pr_lwp.pr_reg[EAX]  = cp->user.u_reg[EAX];
628 		ps->pr_lwp.pr_reg[TRAPNO] = cp->user.u_reg[TRAPNO];
629 		ps->pr_lwp.pr_reg[ERR]  = cp->user.u_reg[ERR];
630 		ps->pr_lwp.pr_reg[EIP]  = cp->user.u_reg[EIP];
631 		ps->pr_lwp.pr_reg[CS]   = cp->user.u_reg[CS];
632 		ps->pr_lwp.pr_reg[EFL]  = cp->user.u_reg[EFL];
633 		ps->pr_lwp.pr_reg[UESP] = cp->user.u_reg[UESP];
634 		ps->pr_lwp.pr_reg[SS]   = cp->user.u_reg[SS];
635 		cmd = PCSREG;
636 		iov[0].iov_base = (caddr_t)&cmd;
637 		iov[0].iov_len = sizeof (long);
638 		iov[1].iov_base = (caddr_t)&ps->pr_lwp.pr_reg[0];
639 		iov[1].iov_len = sizeof (ps->pr_lwp.pr_reg);
640 		(void) writev(cp->ctlfd, iov, 2);
641 		cp->flags &= ~CS_SETREGS;
642 	}
643 
644 	while (pread(cp->statusfd, (char *)ps, sizeof (*ps), (off_t)0) < 0) {
645 		/* attempt to regain control */
646 		if (errno != EINTR &&
647 		    !(errno == EAGAIN && OpenProc(cp) == 0))
648 			return (-1);
649 	}
650 
651 	if (ps->pr_flags & PR_ISTOP)
652 		MakeUser(cp);
653 	else
654 		(void) memset((char *)ps, 0, sizeof (pstatus_t));
655 
656 	return (0);
657 }
658 
659 /*
660  * Manufacture the contents of the fake u-block.
661  */
662 static void
MakeUser(cstatus_t * cp)663 MakeUser(cstatus_t *cp)
664 {
665 	pstatus_t *ps = &cp->pstatus;
666 
667 	cp->user.u_reg[GS]   = ps->pr_lwp.pr_reg[GS];
668 	cp->user.u_reg[FS]   = ps->pr_lwp.pr_reg[FS];
669 	cp->user.u_reg[ES]   = ps->pr_lwp.pr_reg[ES];
670 	cp->user.u_reg[DS]   = ps->pr_lwp.pr_reg[DS];
671 	cp->user.u_reg[EDI]  = ps->pr_lwp.pr_reg[EDI];
672 	cp->user.u_reg[ESI]  = ps->pr_lwp.pr_reg[ESI];
673 	cp->user.u_reg[EBP]  = ps->pr_lwp.pr_reg[EBP];
674 	cp->user.u_reg[ESP]  = ps->pr_lwp.pr_reg[ESP];
675 	cp->user.u_reg[EBX]  = ps->pr_lwp.pr_reg[EBX];
676 	cp->user.u_reg[EDX]  = ps->pr_lwp.pr_reg[EDX];
677 	cp->user.u_reg[ECX]  = ps->pr_lwp.pr_reg[ECX];
678 	cp->user.u_reg[EAX]  = ps->pr_lwp.pr_reg[EAX];
679 	cp->user.u_reg[TRAPNO] = ps->pr_lwp.pr_reg[TRAPNO];
680 	cp->user.u_reg[ERR]  = ps->pr_lwp.pr_reg[ERR];
681 	cp->user.u_reg[EIP]  = ps->pr_lwp.pr_reg[EIP];
682 	cp->user.u_reg[CS]   = ps->pr_lwp.pr_reg[CS];
683 	cp->user.u_reg[EFL]  = ps->pr_lwp.pr_reg[EFL];
684 	cp->user.u_reg[UESP] = ps->pr_lwp.pr_reg[UESP];
685 	cp->user.u_reg[SS]   = ps->pr_lwp.pr_reg[SS];
686 	cp->user.u_ar0 = (greg_t *)REGADDR;
687 	cp->user.u_code = ps->pr_lwp.pr_info.si_code;
688 	cp->user.u_addr = ps->pr_lwp.pr_info.si_addr;
689 	cp->flags &= ~(CS_PSARGS|CS_SIGNAL);
690 }
691 
692 /*
693  * Fetch the contents of u_psargs[].
694  */
695 static void
GetPsargs(cstatus_t * cp)696 GetPsargs(cstatus_t *cp)
697 {
698 	char procname[64];	/* /proc/<pid>/psinfo */
699 	int fd;
700 
701 	MakeProcName(procname, cp->pid);
702 	(void) strcat(procname, "/psinfo");
703 	if ((fd = open(procname, O_RDONLY, 0)) < 0) {
704 		(void) memset(cp->user.u_psargs, 0, PSARGSZ);
705 		return;
706 	}
707 	(void) pread(fd, cp->user.u_psargs, PSARGSZ,
708 	    (off_t)((psinfo_t *)0)->pr_psargs);
709 	(void) close(fd);
710 
711 	cp->flags |= CS_PSARGS;
712 }
713 
714 /*
715  * Fetch the contents of u_signal[].
716  */
717 static void
GetSignal(cstatus_t * cp)718 GetSignal(cstatus_t *cp)
719 {
720 	char procname[64];	/* /proc/<pid>/sigact */
721 	int fd;
722 	struct sigaction action[MAXSIG];
723 	int i;
724 
725 	MakeProcName(procname, cp->pid);
726 	(void) strcat(procname, "/sigact");
727 	(void) memset((char *)action, 0, sizeof (action));
728 	if ((fd = open(procname, O_RDONLY, 0)) >= 0) {
729 		(void) read(fd, (char *)action, sizeof (action));
730 		(void) close(fd);
731 	}
732 	for (i = 0; i < MAXSIG; i++)
733 		cp->user.u_signal[i] = action[i].sa_handler;
734 	cp->flags |= CS_SIGNAL;
735 }
736