amd64-fbsd32.c revision 286789
1/*
2 * Copyright 1997 Sean Eric Fagan
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 * 3. All advertising materials mentioning features or use of this software
13 *    must display the following acknowledgement:
14 *	This product includes software developed by Sean Eric Fagan
15 * 4. Neither the name of the author may be used to endorse or promote
16 *    products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#ifndef lint
33static const char rcsid[] =
34  "$FreeBSD: stable/10/usr.bin/truss/amd64-fbsd32.c 286789 2015-08-14 21:44:42Z emaste $";
35#endif /* not lint */
36
37/*
38 * FreeBSD/i386-specific system call handling.  This is probably the most
39 * complex part of the entire truss program, although I've got lots of
40 * it handled relatively cleanly now.  The system call names are generated
41 * automatically, thanks to /usr/src/sys/kern/syscalls.master.  The
42 * names used for the various structures are confusing, I sadly admit.
43 */
44
45#include <sys/types.h>
46#include <sys/ptrace.h>
47#include <sys/syscall.h>
48
49#include <machine/reg.h>
50#include <machine/psl.h>
51
52#include <errno.h>
53#include <fcntl.h>
54#include <signal.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58#include <time.h>
59#include <unistd.h>
60
61#include "truss.h"
62#include "syscall.h"
63#include "extern.h"
64
65#include "freebsd32_syscalls.h"
66
67static int nsyscalls = sizeof(freebsd32_syscallnames) /
68    sizeof(freebsd32_syscallnames[0]);
69
70/*
71 * This is what this particular file uses to keep track of a system call.
72 * It is probably not quite sufficient -- I can probably use the same
73 * structure for the various syscall personalities, and I also probably
74 * need to nest system calls (for signal handlers).
75 *
76 * 'struct syscall' describes the system call; it may be NULL, however,
77 * if we don't know about this particular system call yet.
78 */
79struct freebsd32_syscall {
80	struct syscall *sc;
81	const char *name;
82	int number;
83	unsigned long *args;
84	unsigned int *args32;
85	int nargs;	/* number of arguments -- *not* number of words! */
86	char **s_args;	/* the printable arguments */
87};
88
89static struct freebsd32_syscall *
90alloc_fsc(void)
91{
92
93	return (malloc(sizeof(struct freebsd32_syscall)));
94}
95
96/* Clear up and free parts of the fsc structure. */
97static void
98free_fsc(struct freebsd32_syscall *fsc)
99{
100	int i;
101
102	free(fsc->args);
103	free(fsc->args32);
104	if (fsc->s_args) {
105		for (i = 0; i < fsc->nargs; i++)
106			free(fsc->s_args[i]);
107		free(fsc->s_args);
108	}
109	free(fsc);
110}
111
112/*
113 * Called when a process has entered a system call.  nargs is the
114 * number of words, not number of arguments (a necessary distinction
115 * in some cases).  Note that if the STOPEVENT() code in i386/i386/trap.c
116 * is ever changed these functions need to keep up.
117 */
118
119void
120amd64_fbsd32_syscall_entry(struct trussinfo *trussinfo, int nargs)
121{
122	struct ptrace_io_desc iorequest;
123	struct reg regs;
124	struct freebsd32_syscall *fsc;
125	struct syscall *sc;
126	lwpid_t tid;
127	unsigned long parm_offset;
128	int i, syscall_num;
129
130	tid = trussinfo->curthread->tid;
131
132	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
133		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
134		return;
135	}
136	parm_offset = regs.r_rsp + sizeof(int);
137
138	/*
139	 * FreeBSD has two special kinds of system call redirctions --
140	 * SYS_syscall, and SYS___syscall.  The former is the old syscall()
141	 * routine, basically; the latter is for quad-aligned arguments.
142	 */
143	syscall_num = regs.r_rax;
144	switch (syscall_num) {
145	case SYS_syscall:
146		syscall_num = ptrace(PT_READ_D, tid, (caddr_t)parm_offset, 0);
147		parm_offset += sizeof(int);
148		break;
149	case SYS___syscall:
150		syscall_num = ptrace(PT_READ_D, tid, (caddr_t)parm_offset, 0);
151		parm_offset += sizeof(quad_t);
152		break;
153	}
154
155	fsc = alloc_fsc();
156	if (fsc == NULL)
157		return;
158	fsc->number = syscall_num;
159	fsc->name = (syscall_num < 0 || syscall_num >= nsyscalls) ?
160	    NULL : freebsd32_syscallnames[syscall_num];
161	if (!fsc->name) {
162		fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n",
163		    syscall_num);
164	}
165
166	if (fsc->name && (trussinfo->flags & FOLLOWFORKS) &&
167	    (strcmp(fsc->name, "fork") == 0 ||
168	    strcmp(fsc->name, "pdfork") == 0 ||
169	    strcmp(fsc->name, "rfork") == 0 ||
170	    strcmp(fsc->name, "vfork") == 0))
171		trussinfo->curthread->in_fork = 1;
172
173	if (nargs == 0)
174		return;
175
176	fsc->args32 = malloc((1 + nargs) * sizeof(unsigned int));
177	iorequest.piod_op = PIOD_READ_D;
178	iorequest.piod_offs = (void *)parm_offset;
179	iorequest.piod_addr = fsc->args32;
180	iorequest.piod_len = (1 + nargs) * sizeof(unsigned int);
181	ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
182	if (iorequest.piod_len == 0)
183		return;
184
185	fsc->args = malloc((1 + nargs) * sizeof(unsigned long));
186	for (i = 0; i < nargs + 1; i++)
187		 fsc->args[i] = fsc->args32[i];
188
189	sc = NULL;
190	if (fsc->name)
191		sc = get_syscall(fsc->name);
192	if (sc)
193		fsc->nargs = sc->nargs;
194	else {
195#if DEBUG
196		fprintf(trussinfo->outfile, "unknown syscall %s -- setting "
197		    "args to %d\n", fsc->name, nargs);
198#endif
199		fsc->nargs = nargs;
200	}
201
202	fsc->s_args = calloc(1, (1 + fsc->nargs) * sizeof(char *));
203	fsc->sc = sc;
204
205	/*
206	 * At this point, we set up the system call arguments.
207	 * We ignore any OUT ones, however -- those are arguments that
208	 * are set by the system call, and so are probably meaningless
209	 * now.	This doesn't currently support arguments that are
210	 * passed in *and* out, however.
211	 */
212
213	if (fsc->name) {
214#if DEBUG
215		fprintf(stderr, "syscall %s(", fsc->name);
216#endif
217		for (i = 0; i < fsc->nargs; i++) {
218#if DEBUG
219			fprintf(stderr, "0x%x%s", sc ?
220			    fsc->args[sc->args[i].offset] : fsc->args[i],
221			    i < (fsc->nargs - 1) ? "," : "");
222#endif
223			if (sc && !(sc->args[i].type & OUT)) {
224				fsc->s_args[i] = print_arg(&sc->args[i],
225				    fsc->args, 0, trussinfo);
226			}
227		}
228#if DEBUG
229		fprintf(stderr, ")\n");
230#endif
231	}
232
233#if DEBUG
234	fprintf(trussinfo->outfile, "\n");
235#endif
236
237	if (fsc->name != NULL && (strcmp(fsc->name, "freebsd32_execve") == 0 ||
238	    strcmp(fsc->name, "exit") == 0)) {
239		/*
240		 * XXX
241		 * This could be done in a more general
242		 * manner but it still wouldn't be very pretty.
243		 */
244		if (strcmp(fsc->name, "freebsd32_execve") == 0) {
245			if ((trussinfo->flags & EXECVEARGS) == 0) {
246				if (fsc->s_args[1]) {
247					free(fsc->s_args[1]);
248					fsc->s_args[1] = NULL;
249				}
250			}
251			if ((trussinfo->flags & EXECVEENVS) == 0) {
252				if (fsc->s_args[2]) {
253					free(fsc->s_args[2]);
254					fsc->s_args[2] = NULL;
255				}
256			}
257		}
258	}
259	trussinfo->curthread->fsc = fsc;
260}
261
262/*
263 * And when the system call is done, we handle it here.
264 * Currently, no attempt is made to ensure that the system calls
265 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
266 * the system call number instead of, say, an error status).
267 */
268
269long
270amd64_fbsd32_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
271{
272	struct reg regs;
273	struct freebsd32_syscall *fsc;
274	struct syscall *sc;
275	lwpid_t tid;
276	long retval;
277	int errorp, i;
278
279	if (trussinfo->curthread->fsc == NULL)
280		return (-1);
281
282	tid = trussinfo->curthread->tid;
283
284	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
285		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
286		return (-1);
287	}
288
289	retval = regs.r_rax;
290	errorp = !!(regs.r_rflags & PSL_C);
291
292	/*
293	 * This code, while simpler than the initial versions I used, could
294	 * stand some significant cleaning.
295	 */
296
297	fsc = trussinfo->curthread->fsc;
298	sc = fsc->sc;
299	if (!sc) {
300		for (i = 0; i < fsc->nargs; i++)
301			asprintf(&fsc->s_args[i], "0x%lx", fsc->args[i]);
302	} else {
303		/*
304		 * Here, we only look for arguments that have OUT masked in --
305		 * otherwise, they were handled in the syscall_entry function.
306		 */
307		for (i = 0; i < sc->nargs; i++) {
308			char *temp;
309			if (sc->args[i].type & OUT) {
310				/*
311				 * If an error occurred, then don't bother
312				 * getting the data; it may not be valid.
313				 */
314				if (errorp) {
315					asprintf(&temp, "0x%lx",
316					    fsc->args[sc->args[i].offset]);
317				} else {
318					temp = print_arg(&sc->args[i],
319					    fsc->args, retval, trussinfo);
320				}
321				fsc->s_args[i] = temp;
322			}
323		}
324	}
325
326	if (fsc->name != NULL && (strcmp(fsc->name, "freebsd32_execve") == 0 ||
327	    strcmp(fsc->name, "exit") == 0))
328		trussinfo->curthread->in_syscall = 1;
329
330	/*
331	 * It would probably be a good idea to merge the error handling,
332	 * but that complicates things considerably.
333	 */
334
335	print_syscall_ret(trussinfo, fsc->name, fsc->nargs, fsc->s_args, errorp,
336	    retval, fsc->sc);
337	free_fsc(fsc);
338
339	return (retval);
340}
341