1/*
2 * Copryight 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: head/usr.bin/truss/amd64-fbsd.c 192025 2009-05-12 20:42:12Z dds $";
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
65static int cpid = -1;
66
67#include "syscalls.h"
68
69static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
70
71/*
72 * This is what this particular file uses to keep track of a system call.
73 * It is probably not quite sufficient -- I can probably use the same
74 * structure for the various syscall personalities, and I also probably
75 * need to nest system calls (for signal handlers).
76 *
77 * 'struct syscall' describes the system call; it may be NULL, however,
78 * if we don't know about this particular system call yet.
79 */
80static struct freebsd_syscall {
81 struct syscall *sc;
82 const char *name;
83 int number;
84 unsigned long *args;
85 int nargs; /* number of arguments -- *not* number of words! */
86 char **s_args; /* the printable arguments */
87} fsc;
88
89/* Clear up and free parts of the fsc structure. */
90static __inline void
91clear_fsc(void) {
92 if (fsc.args) {
93 free(fsc.args);
94 }
95 if (fsc.s_args) {
96 int i;
97 for (i = 0; i < fsc.nargs; i++)
98 if (fsc.s_args[i])
99 free(fsc.s_args[i]);
100 free(fsc.s_args);
101 }
102 memset(&fsc, 0, sizeof(fsc));
103}
104
105/*
106 * Called when a process has entered a system call. nargs is the
107 * number of words, not number of arguments (a necessary distinction
108 * in some cases). Note that if the STOPEVENT() code in amd64/amd64/trap.c
109 * is ever changed these functions need to keep up.
110 */
111
112void
113amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) {
114 struct reg regs;
115 int syscall_num;
116 int i, reg;
117 struct syscall *sc;
118
119 cpid = trussinfo->curthread->tid;
120
121 clear_fsc();
122 if (ptrace(PT_GETREGS, cpid, (caddr_t)&regs, 0) < 0)
123 {
124 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
125 return;
126 }
127
128 /*
129 * FreeBSD has two special kinds of system call redirctions --
130 * SYS_syscall, and SYS___syscall. The former is the old syscall()
131 * routine, basicly; the latter is for quad-aligned arguments.
132 */
133 reg = 0;
134 syscall_num = regs.r_rax;
135 switch (syscall_num) {
136 case SYS_syscall:
137 case SYS___syscall:
138 syscall_num = regs.r_rdi;
139 reg++;
140 break;
141 }
142
143 fsc.number = syscall_num;
144 fsc.name =
145 (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num];
146 if (!fsc.name) {
147 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num);
148 }
149
150 if (fsc.name && (trussinfo->flags & FOLLOWFORKS)
151 && ((!strcmp(fsc.name, "fork")
152 || !strcmp(fsc.name, "rfork")
153 || !strcmp(fsc.name, "vfork"))))
154 {
155 trussinfo->curthread->in_fork = 1;
156 }
157
158 if (nargs == 0)
159 return;
160
161 fsc.args = malloc((1+nargs) * sizeof(unsigned long));
162 for (i = 0; i < nargs && reg < 6; i++, reg++) {
163 switch (reg) {
164 case 0: fsc.args[i] = regs.r_rdi; break;
165 case 1: fsc.args[i] = regs.r_rsi; break;
166 case 2: fsc.args[i] = regs.r_rdx; break;
167 case 3: fsc.args[i] = regs.r_rcx; break;
168 case 4: fsc.args[i] = regs.r_r8; break;
169 case 5: fsc.args[i] = regs.r_r9; break;
170 }
171 }
172 if (nargs > i) {
173 struct ptrace_io_desc iorequest;
174 iorequest.piod_op = PIOD_READ_D;
175 iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t));
176 iorequest.piod_addr = &fsc.args[i];
177 iorequest.piod_len = (nargs - i) * sizeof(register_t);
178 ptrace(PT_IO, cpid, (caddr_t)&iorequest, 0);
179 if (iorequest.piod_len == 0)
180 return;
181 }
182
183 sc = get_syscall(fsc.name);
184 if (sc) {
185 fsc.nargs = sc->nargs;
186 } else {
187#if DEBUG
188 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n",
189 fsc.name, nargs);
190#endif
191 fsc.nargs = nargs;
192 }
193
194 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
195 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
196 fsc.sc = sc;
197
198 /*
199 * At this point, we set up the system call arguments.
200 * We ignore any OUT ones, however -- those are arguments that
201 * are set by the system call, and so are probably meaningless
202 * now. This doesn't currently support arguments that are
203 * passed in *and* out, however.
204 */
205
206 if (fsc.name) {
207
208#if DEBUG
209 fprintf(stderr, "syscall %s(", fsc.name);
210#endif
211 for (i = 0; i < fsc.nargs; i++) {
212#if DEBUG
213 fprintf(stderr, "0x%lx%s",
214 sc
215 ? fsc.args[sc->args[i].offset]
216 : fsc.args[i],
217 i < (fsc.nargs - 1) ? "," : "");
218#endif
219 if (sc && !(sc->args[i].type & OUT)) {
220 fsc.s_args[i] = print_arg(&sc->args[i], fsc.args, 0, trussinfo);
221 }
222 }
223#if DEBUG
224 fprintf(stderr, ")\n");
225#endif
226 }
227
228#if DEBUG
229 fprintf(trussinfo->outfile, "\n");
230#endif
231
232 if (fsc.name != NULL &&
233 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) {
234
235 /* XXX
236 * This could be done in a more general
237 * manner but it still wouldn't be very pretty.
238 */
239 if (!strcmp(fsc.name, "execve")) {
240 if ((trussinfo->flags & EXECVEARGS) == 0)
241 if (fsc.s_args[1]) {
242 free(fsc.s_args[1]);
243 fsc.s_args[1] = NULL;
244 }
245 if ((trussinfo->flags & EXECVEENVS) == 0)
246 if (fsc.s_args[2]) {
247 free(fsc.s_args[2]);
248 fsc.s_args[2] = NULL;
249 }
250 }
251
252 }
253
254 return;
255}
256
257/*
258 * And when the system call is done, we handle it here.
259 * Currently, no attempt is made to ensure that the system calls
260 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
261 * the sytem call number instead of, say, an error status).
262 */
263
264long
265amd64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
266{
267 struct reg regs;
268 long retval;
269 int i;
270 int errorp;
271 struct syscall *sc;
272
273 if (fsc.name == NULL)
274 return (-1);
275
276 cpid = trussinfo->curthread->tid;
277
278 if (ptrace(PT_GETREGS, cpid, (caddr_t)&regs, 0) < 0)
279 {
280 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
281 return (-1);
282 }
283 retval = regs.r_rax;
284 errorp = !!(regs.r_rflags & PSL_C);
285
286 /*
287 * This code, while simpler than the initial versions I used, could
288 * stand some significant cleaning.
289 */
290
291 sc = fsc.sc;
292 if (!sc) {
293 for (i = 0; i < fsc.nargs; i++)
294 asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]);
295 } else {
296 /*
297 * Here, we only look for arguments that have OUT masked in --
298 * otherwise, they were handled in the syscall_entry function.
299 */
300 for (i = 0; i < sc->nargs; i++) {
301 char *temp;
302 if (sc->args[i].type & OUT) {
303 /*
304 * If an error occurred, than don't bothe getting the data;
305 * it may not be valid.
306 */
307 if (errorp)
308 asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]);
309 else
310 temp = print_arg(&sc->args[i], fsc.args, retval, trussinfo);
311 fsc.s_args[i] = temp;
312 }
313 }
314 }
315
316 if (fsc.name != NULL &&
317 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) {
318 trussinfo->curthread->in_syscall = 1;
319 }
320
321 /*
322 * It would probably be a good idea to merge the error handling,
323 * but that complicates things considerably.
324 */
325
326 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp,
327 retval, fsc.sc);
328 clear_fsc();
329
330 return (retval);
331}