/usr.bin/truss/powerpc-fbsd.c

  1/*
  2 * Copyright 2006 Peter Grehan <grehan@freebsd.org>
  3 * Copyright 2005 Orlando Bassotto <orlando@break.net>
  4 * Copyright 1998 Sean Eric Fagan
  5 *
  6 * Redistribution and use in source and binary forms, with or without
  7 * modification, are permitted provided that the following conditions
  8 * are met:
  9 * 1. Redistributions of source code must retain the above copyright
 10 *    notice, this list of conditions and the following disclaimer.
 11 * 2. Redistributions in binary form must reproduce the above copyright
 12 *    notice, this list of conditions and the following disclaimer in the
 13 *    documentation and/or other materials provided with the distribution.
 14 *
 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 25 * SUCH DAMAGE.
 26 */
 27
 28#ifndef lint
 29static const char rcsid[] =
 30  "$FreeBSD$";
 31#endif /* not lint */
 32
 33/*
 34 * FreeBSD/powerpc-specific system call handling.  This is probably the most
 35 * complex part of the entire truss program, although I've got lots of
 36 * it handled relatively cleanly now.  The system call names are generated
 37 * automatically, thanks to /usr/src/sys/kern/syscalls.master.  The
 38 * names used for the various structures are confusing, I sadly admit.
 39 *
 40 * This file is almost nothing more than a slightly-edited i386-fbsd.c.
 41 */
 42
 43#include <sys/types.h>
 44#include <sys/ptrace.h>
 45#include <sys/syscall.h>
 46
 47#include <machine/reg.h>
 48#include <machine/frame.h>
 49
 50#include <err.h>
 51#include <errno.h>
 52#include <fcntl.h>
 53#include <signal.h>
 54#include <stdio.h>
 55#include <stdlib.h>
 56#include <string.h>
 57#include <time.h>
 58#include <unistd.h>
 59
 60#include "truss.h"
 61#include "syscall.h"
 62#include "extern.h"
 63
 64#ifdef __powerpc64__	/* 32-bit compatibility */
 65#include "freebsd32_syscalls.h"
 66#define	syscallnames	freebsd32_syscallnames
 67#else			/* native 32-bit */
 68#include "syscalls.h"
 69#endif
 70
 71static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
 72
 73/*
 74 * This is what this particular file uses to keep track of a system call.
 75 * It is probably not quite sufficient -- I can probably use the same
 76 * structure for the various syscall personalities, and I also probably
 77 * need to nest system calls (for signal handlers).
 78 *
 79 * 'struct syscall' describes the system call; it may be NULL, however,
 80 * if we don't know about this particular system call yet.
 81 */
 82struct freebsd_syscall {
 83	struct syscall *sc;
 84	const char *name;
 85	int number;
 86	unsigned long *args;
 87	int nargs;	/* number of arguments -- *not* number of words! */
 88	char **s_args;	/* the printable arguments */
 89};
 90
 91static struct freebsd_syscall *
 92alloc_fsc(void)
 93{
 94
 95	return (malloc(sizeof(struct freebsd_syscall)));
 96}
 97
 98/* Clear up and free parts of the fsc structure. */
 99static void
100free_fsc(struct freebsd_syscall *fsc)
101{
102	int i;
103
104	free(fsc->args);
105	if (fsc->s_args) {
106		for (i = 0; i < fsc->nargs; i++)
107			free(fsc->s_args[i]);
108		free(fsc->s_args);
109	}
110	free(fsc);
111}
112
113/*
114 * Called when a process has entered a system call.  nargs is the
115 * number of words, not number of arguments (a necessary distinction
116 * in some cases).  Note that if the STOPEVENT() code in powerpc/powerpc/trap.c
117 * is ever changed these functions need to keep up.
118 */
119
120void
121powerpc_syscall_entry(struct trussinfo *trussinfo, int nargs)
122{
123	struct ptrace_io_desc iorequest;
124	struct reg regs;
125	struct freebsd_syscall *fsc;
126	struct syscall *sc;
127	void *args;
128	lwpid_t tid;
129	int i, regargs, syscall_num;
130
131	/* Account for a 64-bit argument with corresponding alignment. */
132	nargs += 2;
133
134	tid = trussinfo->curthread->tid;
135
136	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
137		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
138		return;
139	}
140
141	/*
142	 * FreeBSD has two special kinds of system call redirctions --
143	 * SYS_syscall, and SYS___syscall.  The former is the old syscall()
144	 * routine, basically; the latter is for quad-aligned arguments.
145	 */
146	regargs = NARGREG;
147	syscall_num = regs.fixreg[0];
148	args = &regs.fixreg[3];
149	if (syscall_num == SYS_syscall) {
150		args = &regs.fixreg[4];
151		regargs -= 1;
152		syscall_num = regs.fixreg[3];
153	} else if (syscall_num == SYS___syscall) {
154		args = &regs.fixreg[5];
155		regargs -= 2;
156		syscall_num = regs.fixreg[4];
157	}
158
159	fsc = alloc_fsc();
160	if (fsc == NULL)
161		return;
162	fsc->number = syscall_num;
163	fsc->name = (syscall_num < 0 || syscall_num >= nsyscalls) ?
164	    NULL : syscallnames[syscall_num];
165	if (!fsc->name) {
166		fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n",
167		    syscall_num);
168	}
169
170	if (fsc->name && (trussinfo->flags & FOLLOWFORKS) &&
171	    (strcmp(fsc->name, "fork") == 0 ||
172	    strcmp(fsc->name, "rfork") == 0 ||
173	    strcmp(fsc->name, "vfork") == 0))
174		trussinfo->curthread->in_fork = 1;
175
176	if (nargs == 0)
177		return;
178
179	fsc->args = malloc((1 + nargs) * sizeof(unsigned long));
180
181	if (nargs > regargs) {
182		memmove(&fsc->args[0], args, regargs * sizeof(fsc->args[0]));
183
184		iorequest.piod_op = PIOD_READ_D;
185		iorequest.piod_offs = (void *)(regs.fixreg[1] + 8);
186		iorequest.piod_addr = &fsc->args[regargs];
187		iorequest.piod_len = (nargs - regargs) * sizeof(fsc->args[0]);
188		ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
189		if (iorequest.piod_len == 0)
190			return;
191	} else
192		memmove(&fsc->args[0], args, nargs * sizeof(fsc->args[0]));
193
194	sc = get_syscall(fsc->name);
195	if (sc)
196		fsc->nargs = sc->nargs;
197	else {
198#if DEBUG
199		fprintf(trussinfo->outfile, "unknown syscall %s -- setting "
200		    "args to %d\n", fsc->name, nargs);
201#endif
202		fsc->nargs = nargs;
203	}
204
205	fsc->s_args = calloc(1, (1 + fsc->nargs) * sizeof(char *));
206	fsc->sc = sc;
207
208	/*
209	 * At this point, we set up the system call arguments.
210	 * We ignore any OUT ones, however -- those are arguments that
211	 * are set by the system call, and so are probably meaningless
212	 * now.	This doesn't currently support arguments that are
213	 * passed in *and* out, however.
214	 */
215
216	if (fsc->name) {
217#if DEBUG
218		fprintf(stderr, "syscall %s(", fsc->name);
219#endif
220		for (i = 0; i < fsc->nargs; i++) {
221#if DEBUG
222			fprintf(stderr, "0x%x%s", sc ?
223			    fsc->args[sc->args[i].offset] : fsc->args[i],
224			    i < (fsc->nargs - 1) ? "," : "");
225#endif
226			if (sc && !(sc->args[i].type & OUT)) {
227				fsc->s_args[i] = print_arg(&sc->args[i],
228				    fsc->args, 0, trussinfo);
229			}
230		}
231#if DEBUG
232		fprintf(stderr, ")\n");
233#endif
234	}
235
236#if DEBUG
237	fprintf(trussinfo->outfile, "\n");
238#endif
239
240	if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 ||
241	    strcmp(fsc->name, "exit") == 0)) {
242		/*
243		 * XXX
244		 * This could be done in a more general
245		 * manner but it still wouldn't be very pretty.
246		 */
247		if (strcmp(fsc->name, "execve") == 0) {
248			if ((trussinfo->flags & EXECVEARGS) == 0) {
249				if (fsc->s_args[1]) {
250					free(fsc->s_args[1]);
251					fsc->s_args[1] = NULL;
252				}
253			}
254			if ((trussinfo->flags & EXECVEENVS) == 0) {
255				if (fsc->s_args[2]) {
256					free(fsc->s_args[2]);
257					fsc->s_args[2] = NULL;
258				}
259			}
260		}
261	}
262	trussinfo->curthread->fsc = fsc;
263}
264
265/*
266 * And when the system call is done, we handle it here.
267 * Currently, no attempt is made to ensure that the system calls
268 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
269 * the system call number instead of, say, an error status).
270 */
271
272long
273powerpc_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
274{
275	struct reg regs;
276	struct freebsd_syscall *fsc;
277	struct syscall *sc;
278	lwpid_t tid;
279	long retval;
280	int errorp, i;
281
282	if (trussinfo->curthread->fsc == NULL)
283		return (-1);
284
285	tid = trussinfo->curthread->tid;
286
287	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
288		fprintf(trussinfo->outfile, "\n");
289		return (-1);
290	}
291
292	retval = regs.fixreg[3];
293	errorp = !!(regs.cr & 0x10000000);
294
295	/*
296	 * This code, while simpler than the initial versions I used, could
297	 * stand some significant cleaning.
298	 */
299
300	fsc = trussinfo->curthread->fsc;
301	sc = fsc->sc;
302	if (!sc) {
303		for (i = 0; i < fsc->nargs; i++)
304			asprintf(&fsc->s_args[i], "0x%lx", fsc->args[i]);
305	} else {
306		/*
307		 * On 32-bit big-endian, the low word of a 64-bit return is
308		 * in the greater address. Switch to this. XXX note that
309		 * print_syscall_ret can't handle 64-bit return values (llseek)
310		 */
311		if (sc->ret_type == 2)
312			retval = regs.fixreg[4];
313
314		/*
315		 * Here, we only look for arguments that have OUT masked in --
316		 * otherwise, they were handled in the syscall_entry function.
317		 */
318		for (i = 0; i < sc->nargs; i++) {
319			char *temp;
320			if (sc->args[i].type & OUT) {
321				/*
322				 * If an error occurred, then don't bother
323				 * getting the data; it may not be valid.
324				 */
325				if (errorp) {
326					asprintf(&temp, "0x%lx",
327					    fsc->args[sc->args[i].offset]);
328				} else {
329					temp = print_arg(&sc->args[i],
330					    fsc->args, retval, trussinfo);
331				}
332				fsc->s_args[i] = temp;
333			}
334		}
335	}
336
337	if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 ||
338	    strcmp(fsc->name, "exit") == 0))
339		trussinfo->curthread->in_syscall = 1;
340
341	/*
342	 * It would probably be a good idea to merge the error handling,
343	 * but that complicates things considerably.
344	 */
345
346	print_syscall_ret(trussinfo, fsc->name, fsc->nargs, fsc->s_args, errorp,
347	    retval, fsc->sc);
348	free_fsc(fsc);
349
350	return (retval);
351}