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  "$FreeBSD$";
35#endif /* not lint */
36
37/*
38 * FreeBSD/amd64-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 "syscalls.h"
66
67static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
68
69/*
70 * This is what this particular file uses to keep track of a system call.
71 * It is probably not quite sufficient -- I can probably use the same
72 * structure for the various syscall personalities, and I also probably
73 * need to nest system calls (for signal handlers).
74 *
75 * 'struct syscall' describes the system call; it may be NULL, however,
76 * if we don't know about this particular system call yet.
77 */
78struct freebsd_syscall {
79	struct syscall *sc;
80	const char *name;
81	int number;
82	unsigned long *args;
83	int nargs;	/* number of arguments -- *not* number of words! */
84	char **s_args;	/* the printable arguments */
85};
86
87static struct freebsd_syscall *
88alloc_fsc(void)
89{
90
91	return (malloc(sizeof(struct freebsd_syscall)));
92}
93
94/* Clear up and free parts of the fsc structure. */
95static void
96free_fsc(struct freebsd_syscall *fsc)
97{
98	int i;
99
100	free(fsc->args);
101	if (fsc->s_args) {
102		for (i = 0; i < fsc->nargs; i++)
103			free(fsc->s_args[i]);
104		free(fsc->s_args);
105	}
106	free(fsc);
107}
108
109/*
110 * Called when a process has entered a system call.  nargs is the
111 * number of words, not number of arguments (a necessary distinction
112 * in some cases).  Note that if the STOPEVENT() code in amd64/amd64/trap.c
113 * is ever changed these functions need to keep up.
114 */
115
116void
117amd64_syscall_entry(struct trussinfo *trussinfo, int nargs)
118{
119	struct ptrace_io_desc iorequest;
120	struct reg regs;
121	struct freebsd_syscall *fsc;
122	struct syscall *sc;
123	lwpid_t tid;
124	int i, reg, syscall_num;
125
126	tid = trussinfo->curthread->tid;
127
128	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
129		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
130		return;
131	}
132
133	/*
134	 * FreeBSD has two special kinds of system call redirctions --
135	 * SYS_syscall, and SYS___syscall.  The former is the old syscall()
136	 * routine, basically; the latter is for quad-aligned arguments.
137	 */
138	reg = 0;
139	syscall_num = regs.r_rax;
140	switch (syscall_num) {
141	case SYS_syscall:
142	case SYS___syscall:
143		syscall_num = regs.r_rdi;
144		reg++;
145		break;
146	}
147
148	fsc = alloc_fsc();
149	if (fsc == NULL)
150		return;
151	fsc->number = syscall_num;
152	fsc->name = (syscall_num < 0 || syscall_num >= nsyscalls) ?
153	    NULL : syscallnames[syscall_num];
154	if (!fsc->name) {
155		fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n",
156		    syscall_num);
157	}
158
159	if (fsc->name && (trussinfo->flags & FOLLOWFORKS) &&
160	    (strcmp(fsc->name, "fork") == 0 ||
161	    strcmp(fsc->name, "rfork") == 0 ||
162	    strcmp(fsc->name, "vfork") == 0))
163		trussinfo->curthread->in_fork = 1;
164
165	if (nargs == 0)
166		return;
167
168	fsc->args = malloc((1 + nargs) * sizeof(unsigned long));
169	for (i = 0; i < nargs && reg < 6; i++, reg++) {
170		switch (reg) {
171		case 0: fsc->args[i] = regs.r_rdi; break;
172		case 1: fsc->args[i] = regs.r_rsi; break;
173		case 2: fsc->args[i] = regs.r_rdx; break;
174		case 3: fsc->args[i] = regs.r_rcx; break;
175		case 4: fsc->args[i] = regs.r_r8; break;
176		case 5: fsc->args[i] = regs.r_r9; break;
177		}
178	}
179	if (nargs > i) {
180		iorequest.piod_op = PIOD_READ_D;
181		iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t));
182		iorequest.piod_addr = &fsc->args[i];
183		iorequest.piod_len = (nargs - i) * sizeof(register_t);
184		ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
185		if (iorequest.piod_len == 0)
186			return;
187	}
188
189	sc = get_syscall(fsc->name);
190	if (sc)
191		fsc->nargs = sc->nargs;
192	else {
193#if DEBUG
194		fprintf(trussinfo->outfile, "unknown syscall %s -- setting "
195		    "args to %d\n", fsc->name, nargs);
196#endif
197		fsc->nargs = nargs;
198	}
199
200	fsc->s_args = calloc(1, (1 + fsc->nargs) * sizeof(char *));
201	fsc->sc = sc;
202
203	/*
204	 * At this point, we set up the system call arguments.
205	 * We ignore any OUT ones, however -- those are arguments that
206	 * are set by the system call, and so are probably meaningless
207	 * now.	This doesn't currently support arguments that are
208	 * passed in *and* out, however.
209	 */
210
211	if (fsc->name) {
212#if DEBUG
213		fprintf(stderr, "syscall %s(", fsc->name);
214#endif
215		for (i = 0; i < fsc->nargs; i++) {
216#if DEBUG
217			fprintf(stderr, "0x%lx%s", sc ?
218			    fsc->args[sc->args[i].offset] : fsc->args[i],
219			    i < (fsc->nargs - 1) ? "," : "");
220#endif
221			if (sc && !(sc->args[i].type & OUT)) {
222				fsc->s_args[i] = print_arg(&sc->args[i],
223				    fsc->args, 0, trussinfo);
224			}
225		}
226#if DEBUG
227		fprintf(stderr, ")\n");
228#endif
229	}
230
231#if DEBUG
232	fprintf(trussinfo->outfile, "\n");
233#endif
234
235	if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 ||
236	    strcmp(fsc->name, "exit") == 0)) {
237		/*
238		 * XXX
239		 * This could be done in a more general
240		 * manner but it still wouldn't be very pretty.
241		 */
242		if (strcmp(fsc->name, "execve") == 0) {
243			if ((trussinfo->flags & EXECVEARGS) == 0) {
244				if (fsc->s_args[1]) {
245					free(fsc->s_args[1]);
246					fsc->s_args[1] = NULL;
247				}
248			}
249			if ((trussinfo->flags & EXECVEENVS) == 0) {
250				if (fsc->s_args[2]) {
251					free(fsc->s_args[2]);
252					fsc->s_args[2] = NULL;
253				}
254			}
255		}
256	}
257	trussinfo->curthread->fsc = fsc;
258}
259
260/*
261 * And when the system call is done, we handle it here.
262 * Currently, no attempt is made to ensure that the system calls
263 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
264 * the system call number instead of, say, an error status).
265 */
266
267long
268amd64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
269{
270	struct reg regs;
271	struct freebsd_syscall *fsc;
272	struct syscall *sc;
273	lwpid_t tid;
274	long retval;
275	int errorp, i;
276
277	if (trussinfo->curthread->fsc == NULL)
278		return (-1);
279
280	tid = trussinfo->curthread->tid;
281
282	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
283		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
284		return (-1);
285	}
286
287	retval = regs.r_rax;
288	errorp = !!(regs.r_rflags & PSL_C);
289
290	/*
291	 * This code, while simpler than the initial versions I used, could
292	 * stand some significant cleaning.
293	 */
294
295	fsc = trussinfo->curthread->fsc;
296	sc = fsc->sc;
297	if (!sc) {
298		for (i = 0; i < fsc->nargs; i++)
299			asprintf(&fsc->s_args[i], "0x%lx", fsc->args[i]);
300	} else {
301		/*
302		 * Here, we only look for arguments that have OUT masked in --
303		 * otherwise, they were handled in the syscall_entry function.
304		 */
305		for (i = 0; i < sc->nargs; i++) {
306			char *temp;
307			if (sc->args[i].type & OUT) {
308				/*
309				 * If an error occurred, then don't bother
310				 * getting the data; it may not be valid.
311				 */
312				if (errorp) {
313					asprintf(&temp, "0x%lx",
314					    fsc->args[sc->args[i].offset]);
315				} else {
316					temp = print_arg(&sc->args[i],
317					    fsc->args, retval, trussinfo);
318				}
319				fsc->s_args[i] = temp;
320			}
321		}
322	}
323
324	if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 ||
325	    strcmp(fsc->name, "exit") == 0))
326		trussinfo->curthread->in_syscall = 1;
327
328	/*
329	 * It would probably be a good idea to merge the error handling,
330	 * but that complicates things considerably.
331	 */
332
333	print_syscall_ret(trussinfo, fsc->name, fsc->nargs, fsc->s_args, errorp,
334	    retval, fsc->sc);
335	free_fsc(fsc);
336
337	return (retval);
338}
339