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
29 static 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
71 static 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 */
82 struct 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
91 static struct freebsd_syscall *
alloc_fsc(void)92 alloc_fsc(void)
93 {
94
95 return (malloc(sizeof(struct freebsd_syscall)));
96 }
97
98 /* Clear up and free parts of the fsc structure. */
99 static void
free_fsc(struct freebsd_syscall * fsc)100 free_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
120 void
powerpc_syscall_entry(struct trussinfo * trussinfo,int nargs)121 powerpc_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)®s, 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 = ®s.fixreg[3];
149 if (syscall_num == SYS_syscall) {
150 args = ®s.fixreg[4];
151 regargs -= 1;
152 syscall_num = regs.fixreg[3];
153 } else if (syscall_num == SYS___syscall) {
154 args = ®s.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
272 long
powerpc_syscall_exit(struct trussinfo * trussinfo,int syscall_num __unused)273 powerpc_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)®s, 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 }
352