xref: /freebsd/usr.bin/truss/syscalls.c (revision d37ea99837e6ad50837fd9fe1771ddf1c3ba6002)
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
33 static const char rcsid[] =
34   "$FreeBSD$";
35 #endif /* not lint */
36 
37 /*
38  * This file has routines used to print out system calls and their
39  * arguments.
40  */
41 
42 #include <sys/mman.h>
43 #include <sys/types.h>
44 #include <sys/socket.h>
45 #include <sys/time.h>
46 #include <sys/un.h>
47 #include <netinet/in.h>
48 #include <arpa/inet.h>
49 
50 #include <ctype.h>
51 #include <err.h>
52 #include <fcntl.h>
53 #include <poll.h>
54 #include <signal.h>
55 #include <stdint.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <time.h>
60 #include <unistd.h>
61 
62 #include "truss.h"
63 #include "extern.h"
64 #include "syscall.h"
65 
66 /*
67  * This should probably be in its own file.
68  */
69 
70 struct syscall syscalls[] = {
71 	{ "fcntl", 1, 3,
72 	  { { Int, 0 } , { Fcntl, 1 }, { Hex, 2 }}},
73 	{ "readlink", 1, 3,
74 	  { { String, 0 } , { String | OUT, 1 }, { Int, 2 }}},
75 	{ "lseek", 2, 3,
76 	  { { Int, 0 }, {Quad, 2 }, { Int, 4 }}},
77 	{ "mmap", 2, 6,
78 	  { { Ptr, 0 }, {Int, 1}, {Mprot, 2}, {Mmapflags, 3}, {Int, 4}, {Quad, 6}}},
79 	{ "mprotect", 1, 3,
80 	  { { Ptr, 0 }, {Int, 1}, {Mprot, 2}}},
81 	{ "open", 1, 3,
82 	  { { String | IN, 0} , { Hex, 1}, {Octal, 2}}},
83 	{ "linux_open", 1, 3,
84 	  { { String, 0 }, { Hex, 1}, { Octal, 2 }}},
85 	{ "close", 1, 1,
86 	  { { Int, 0 } } },
87 	{ "link", 0, 2,
88 	  { { String, 0 }, { String, 1 }}},
89 	{ "unlink", 0, 1,
90 	  { { String, 0 }}},
91 	{ "chdir", 0, 1,
92 	  { { String, 0 }}},
93 	{ "mknod", 0, 3,
94 	  { { String, 0 }, { Octal, 1 }, { Int, 3 }}},
95 	{ "chmod", 0, 2,
96 	  { { String, 0 }, { Octal, 1 }}},
97 	{ "chown", 0, 3,
98 	  { { String, 0 }, { Int, 1 }, { Int, 2 }}},
99 	{ "mount", 0, 4,
100 	  { { String, 0 }, { String, 1 }, { Int, 2 }, { Ptr, 3 }}},
101 	{ "umount", 0, 2,
102 	  { { String, 0 }, { Int, 2 }}},
103 	{ "fstat", 1, 2,
104 	  { { Int, 0},  {Ptr | OUT , 1 }}},
105 	{ "stat", 1, 2,
106 	  { { String | IN, 0 }, { Ptr | OUT, 1 }}},
107 	{ "lstat", 1, 2,
108 	  { { String | IN, 0 }, { Ptr | OUT, 1 }}},
109 	{ "linux_newstat", 1, 2,
110 	  { { String | IN, 0 }, { Ptr | OUT, 1 }}},
111 	{ "linux_newfstat", 1, 2,
112 	  { { Int, 0 }, { Ptr | OUT, 1 }}},
113 	{ "write", 1, 3,
114 	  { { Int, 0 }, { Ptr | IN, 1 }, { Int, 2 }}},
115 	{ "ioctl", 1, 3,
116 	  { { Int, 0 }, { Ioctl, 1 }, { Hex, 2 }}},
117 	{ "break", 1, 1, { { Hex, 0 }}},
118 	{ "exit", 0, 1, { { Hex, 0 }}},
119 	{ "access", 1, 2, { { String | IN, 0 }, { Int, 1 }}},
120 	{ "sigaction", 1, 3,
121 	  { { Signal, 0 }, { Sigaction | IN, 1 }, { Sigaction | OUT, 2 }}},
122 	{ "accept", 1, 3,
123 	  { { Hex, 0 }, { Sockaddr | OUT, 1 }, { Ptr | OUT, 2 } } },
124 	{ "bind", 1, 3,
125 	  { { Hex, 0 }, { Sockaddr | IN, 1 }, { Int, 2 } } },
126 	{ "connect", 1, 3,
127 	  { { Hex, 0 }, { Sockaddr | IN, 1 }, { Int, 2 } } },
128 	{ "getpeername", 1, 3,
129 	  { { Hex, 0 }, { Sockaddr | OUT, 1 }, { Ptr | OUT, 2 } } },
130 	{ "getsockname", 1, 3,
131 	  { { Hex, 0 }, { Sockaddr | OUT, 1 }, { Ptr | OUT, 2 } } },
132 	{ "recvfrom", 1, 6,
133 	  { { Hex, 0 }, { Ptr | IN, 1 }, { Int, 3 }, { Hex, 3 }, { Sockaddr | OUT, 4 }, { Ptr | OUT, 5 } } },
134 	{ "sendto", 1, 6,
135 	  { { Hex, 0 }, { Ptr | IN, 1 }, { Int, 3 }, { Hex, 3 }, { Sockaddr | IN, 4 }, { Ptr | IN, 5 } } },
136 	{ "execve", 1, 3,
137 	  { { String | IN, 0 }, { StringArray | IN, 1 }, { StringArray | IN, 2 } } },
138 	{ "linux_execve", 1, 3,
139 	  { { String | IN, 0 }, { StringArray | IN, 1 }, { StringArray | IN, 2 } } },
140 	{ "kldload", 0, 1, { { String | IN, 0 }}},
141 	{ "kldunload", 0, 1, { { Int, 0 }}},
142 	{ "kldfind", 0, 1, { { String | IN, 0 }}},
143 	{ "kldnext", 0, 1, { { Int, 0 }}},
144 	{ "kldstat", 0, 2, { { Int, 0 }, { Ptr, 1 }}},
145 	{ "kldfirstmod", 0, 1, { { Int, 0 }}},
146 	{ "nanosleep", 0, 1, { { Timespec, 0 }}},
147 	{ "select", 1, 5, { { Int, 0 }, { Fd_set, 1 }, { Fd_set, 2 }, { Fd_set, 3 }, { Timeval, 4 }}},
148 	{ "poll", 1, 3, { { Pollfd, 0 }, { Int, 1 }, { Int, 2 }}},
149 	{ "gettimeofday", 1, 2, { { Timeval | OUT, 0 }, { Ptr, 1 }}},
150 	{ "clock_gettime", 1, 2, { { Int, 0 }, { Timeval | OUT, 1 }}},
151 	{ "recvfrom", 1, 6, { { Int, 0 }, { Ptr | OUT, 1 }, { Int, 2 }, { Int, 3 }, { Sockaddr | OUT, 4}, {Ptr | OUT, 5}}},
152 	{ "getitimer", 1, 2, { { Int, 0 }, { Itimerval | OUT, 2 }}},
153 	{ "setitimer", 1, 3, { { Int, 0 }, { Itimerval, 1} , { Itimerval | OUT, 2 }}},
154 	{ 0, 0, 0, { { 0, 0 }}},
155 };
156 
157 /*
158  * If/when the list gets big, it might be desirable to do it
159  * as a hash table or binary search.
160  */
161 
162 struct syscall *
163 get_syscall(const char *name) {
164 	struct syscall *sc = syscalls;
165 
166 	while (sc->name) {
167 		if (!strcmp(name, sc->name))
168 			return sc;
169 		sc++;
170 	}
171 	return NULL;
172 }
173 
174 /*
175  * get_struct
176  *
177  * Copy a fixed amount of bytes from the process.
178  */
179 
180 static int
181 get_struct(int procfd, void *offset, void *buf, int len) {
182 
183 	if (pread(procfd, buf, len, (uintptr_t)offset) != len)
184 		return -1;
185 	return 0;
186 }
187 
188 /*
189  * get_string
190  * Copy a string from the process.  Note that it is
191  * expected to be a C string, but if max is set, it will
192  * only get that much.
193  */
194 
195 char *
196 get_string(int procfd, void *offset, int max) {
197 	char *buf;
198 	int size, len, c, fd;
199 	FILE *p;
200 
201 	if ((fd = dup(procfd)) == -1)
202 		err(1, "dup");
203 	if ((p = fdopen(fd, "r")) == NULL)
204 		err(1, "fdopen");
205 	buf = malloc( size = (max ? max : 64 ) );
206 	len = 0;
207 	buf[0] = 0;
208 	if (fseeko(p, (uintptr_t)offset, SEEK_SET) == 0) {
209 		while ((c = fgetc(p)) != EOF) {
210 			buf[len++] = c;
211 			if (c == 0 || len == max) {
212 				buf[len] = 0;
213 				break;
214 			}
215 			if (len == size) {
216 				char *tmp;
217 				tmp = realloc(buf, size+64);
218 				if (tmp == NULL) {
219 					buf[len] = 0;
220 					break;
221 				}
222 				size += 64;
223 				buf = tmp;
224 			}
225 		}
226 	}
227 	fclose(p);
228 	return (buf);
229 }
230 
231 
232 /*
233  * Gag.  This is really unportable.  Multiplication is more portable.
234  * But slower, from the code I saw.
235  */
236 
237 static long long
238 make_quad(unsigned long p1, unsigned long p2) {
239   union {
240     long long ll;
241     unsigned long l[2];
242   } t;
243   t.l[0] = p1;
244   t.l[1] = p2;
245   return t.ll;
246 }
247 
248 /*
249  * Remove a trailing '|' in a string, useful for fixup after decoding
250  * a "flags" argument.
251  */
252 
253 void
254 remove_trailing_or(char *str)
255 {
256 
257 	if (str != NULL && (str = rindex(str, '|')) != NULL && str[1] == '\0')
258 		*str = '\0';
259 }
260 
261 /*
262  * print_arg
263  * Converts a syscall argument into a string.  Said string is
264  * allocated via malloc(), so needs to be free()'d.  The file
265  * descriptor is for the process' memory (via /proc), and is used
266  * to get any data (where the argument is a pointer).  sc is
267  * a pointer to the syscall description (see above); args is
268  * an array of all of the system call arguments.
269  */
270 
271 char *
272 print_arg(int fd, struct syscall_args *sc, unsigned long *args) {
273   char *tmp = NULL;
274   switch (sc->type & ARG_MASK) {
275   case Hex:
276     asprintf(&tmp, "0x%lx", args[sc->offset]);
277     break;
278   case Octal:
279     asprintf(&tmp, "0%lo", args[sc->offset]);
280     break;
281   case Int:
282     asprintf(&tmp, "%ld", args[sc->offset]);
283     break;
284   case String:
285     {
286       char *tmp2;
287       tmp2 = get_string(fd, (void*)args[sc->offset], 0);
288       asprintf(&tmp, "\"%s\"", tmp2);
289       free(tmp2);
290     }
291   break;
292   case StringArray:
293     {
294       int num, size, i;
295       char *tmp2;
296       char *string;
297       char *strarray[100];	/* XXX This is ugly. */
298 
299       if (get_struct(fd, (void *)args[sc->offset], (void *)&strarray,
300                      sizeof(strarray)) == -1) {
301 	err(1, "get_struct %p", (void *)args[sc->offset]);
302       }
303       num = 0;
304       size = 0;
305 
306       /* Find out how large of a buffer we'll need. */
307       while (strarray[num] != NULL) {
308 	string = get_string(fd, (void*)strarray[num], 0);
309         size += strlen(string);
310 	free(string);
311 	num++;
312       }
313       size += 4 + (num * 4);
314       tmp = (char *)malloc(size);
315       tmp2 = tmp;
316 
317       tmp2 += sprintf(tmp2, " [");
318       for (i = 0; i < num; i++) {
319 	string = get_string(fd, (void*)strarray[i], 0);
320         tmp2 += sprintf(tmp2, " \"%s\"%c", string, (i+1 == num) ? ' ' : ',');
321 	free(string);
322       }
323       tmp2 += sprintf(tmp2, "]");
324     }
325   break;
326   case Quad:
327     {
328       unsigned long long t;
329       unsigned long l1, l2;
330       l1 = args[sc->offset];
331       l2 = args[sc->offset+1];
332       t = make_quad(l1, l2);
333       asprintf(&tmp, "0x%qx", t);
334       break;
335     }
336   case Ptr:
337     asprintf(&tmp, "0x%lx", args[sc->offset]);
338     break;
339   case Ioctl:
340     {
341       const char *temp = ioctlname(args[sc->offset]);
342       if (temp)
343 	tmp = strdup(temp);
344       else
345 	asprintf(&tmp, "0x%lx", args[sc->offset]);
346     }
347     break;
348   case Timespec:
349     {
350       struct timespec ts;
351       if (get_struct(fd, (void *)args[sc->offset], &ts, sizeof(ts)) != -1)
352 	asprintf(&tmp, "{%jd %jd}", (intmax_t)ts.tv_sec, (intmax_t)ts.tv_nsec);
353       else
354 	asprintf(&tmp, "0x%lx", args[sc->offset]);
355     }
356     break;
357   case Timeval:
358     {
359       struct timeval tv;
360       if (get_struct(fd, (void *)args[sc->offset], &tv, sizeof(tv)) != -1)
361 	asprintf(&tmp, "{%jd %jd}", (intmax_t)tv.tv_sec, (intmax_t)tv.tv_usec);
362       else
363 	asprintf(&tmp, "0x%lx", args[sc->offset]);
364     }
365     break;
366   case Itimerval:
367     {
368       struct itimerval itv;
369       if (get_struct(fd, (void *)args[sc->offset], &itv, sizeof(itv)) != -1)
370 	asprintf(&tmp, "{%jd %jd, %jd %jd}",
371 	    (intmax_t)itv.it_interval.tv_sec,
372 	    (intmax_t)itv.it_interval.tv_usec,
373 	    (intmax_t)itv.it_value.tv_sec,
374 	    (intmax_t)itv.it_value.tv_usec);
375       else
376 	asprintf(&tmp, "0x%lx", args[sc->offset]);
377     }
378     break;
379   case Pollfd:
380     {
381       /*
382        * XXX: A Pollfd argument expects the /next/ syscall argument to be
383        * the number of fds in the array. This matches the poll syscall.
384        */
385       struct pollfd *pfd;
386       int numfds = args[sc->offset+1];
387       int bytes = sizeof(struct pollfd) * numfds;
388       int i, tmpsize, u, used;
389       const int per_fd = 100;
390 
391       if ((pfd = malloc(bytes)) == NULL)
392 	err(1, "Cannot malloc %d bytes for pollfd array", bytes);
393       if (get_struct(fd, (void *)args[sc->offset], pfd, bytes) != -1) {
394 
395 	used = 0;
396 	tmpsize = 1 + per_fd * numfds + 2;
397 	if ((tmp = malloc(tmpsize)) == NULL)
398 	  err(1, "Cannot alloc %d bytes for poll output", tmpsize);
399 
400 	tmp[used++] = '{';
401 	for (i = 0; i < numfds; i++) {
402 #define POLLKNOWN_EVENTS \
403 	(POLLIN | POLLPRI | POLLOUT | POLLERR | POLLHUP | POLLNVAL | \
404 	 POLLRDNORM |POLLRDBAND | POLLWRBAND | POLLINIGNEOF)
405 
406 	  u += snprintf(tmp + used, per_fd,
407 	    "%s%d 0x%hx%s%s%s%s%s%s%s%s%s ",
408 	    i > 0 ? " " : "",
409 	    pfd[i].fd,
410 	    pfd[i].events & ~POLLKNOWN_EVENTS,
411 	    pfd[i].events & POLLIN ? "" : "|IN",
412 	    pfd[i].events & POLLPRI ? "" : "|PRI",
413 	    pfd[i].events & POLLOUT ? "" : "|OUT",
414 	    pfd[i].events & POLLERR ? "" : "|ERR",
415 	    pfd[i].events & POLLHUP ? "" : "|HUP",
416 	    pfd[i].events & POLLNVAL ? "" : "|NVAL",
417 	    pfd[i].events & POLLRDNORM ? "" : "|RDNORM",
418 	    pfd[i].events & POLLRDBAND ? "" : "|RDBAND",
419 	    pfd[i].events & POLLWRBAND ? "" : "|WRBAND");
420 	  if (u > 0)
421 	    used += u < per_fd ? u : per_fd;
422 	}
423 	tmp[used++] = '}';
424 	tmp[used++] = '\0';
425       } else
426 	asprintf(&tmp, "0x%lx", args[sc->offset]);
427       free(pfd);
428     }
429     break;
430   case Fd_set:
431     {
432       /*
433        * XXX: A Fd_set argument expects the /first/ syscall argument to be
434        * the number of fds in the array.  This matches the select syscall.
435        */
436       fd_set *fds;
437       int numfds = args[0];
438       int bytes = _howmany(numfds, _NFDBITS) * _NFDBITS;
439       int i, tmpsize, u, used;
440       const int per_fd = 20;
441 
442       if ((fds = malloc(bytes)) == NULL)
443 	err(1, "Cannot malloc %d bytes for fd_set array", bytes);
444       if (get_struct(fd, (void *)args[sc->offset], fds, bytes) != -1) {
445 	used = 0;
446 	tmpsize = 1 + numfds * per_fd + 2;
447 	if ((tmp = malloc(tmpsize)) == NULL)
448 	  err(1, "Cannot alloc %d bytes for fd_set output", tmpsize);
449 
450 	tmp[used++] = '{';
451 	for (i = 0; i < numfds; i++) {
452 	  if (FD_ISSET(i, fds)) {
453 	    u = snprintf(tmp + used, per_fd, "%d ", i);
454 	    if (u > 0)
455 	      used += u < per_fd ? u : per_fd;
456 	  }
457 	}
458 	if (tmp[used-1] == ' ')
459 		used--;
460 	tmp[used++] = '}';
461 	tmp[used++] = '\0';
462       } else
463 	asprintf(&tmp, "0x%lx", args[sc->offset]);
464       free(fds);
465     }
466     break;
467   case Signal:
468     {
469       long sig;
470 
471       sig = args[sc->offset];
472       if (sig > 0 && sig < NSIG) {
473 	int i;
474 	asprintf(&tmp, "sig%s", sys_signame[sig]);
475 	for (i = 0; tmp[i] != '\0'; ++i)
476 	  tmp[i] = toupper(tmp[i]);
477       } else
478         asprintf(&tmp, "%ld", sig);
479     }
480     break;
481   case Fcntl:
482     {
483 	switch (args[sc->offset]) {
484 #define S(a)	case a: tmp = strdup(#a); break;
485 	S(F_DUPFD);
486 	S(F_GETFD);
487 	S(F_SETFD);
488 	S(F_GETFL);
489 	S(F_SETFL);
490 	S(F_GETOWN);
491 	S(F_SETOWN);
492 	S(F_GETLK);
493 	S(F_SETLK);
494 	S(F_SETLKW);
495 #undef S
496 	}
497 	if (tmp == NULL)
498     		asprintf(&tmp, "0x%lx", args[sc->offset]);
499     }
500     break;
501 
502   case Mprot:
503     {
504 
505 #define S(a)	((args[sc->offset] & a) ? #a "|" : "")
506 	    asprintf(&tmp, "(0x%lx)%s%s%s%s", args[sc->offset],
507 		S(PROT_NONE), S(PROT_READ), S(PROT_WRITE), S(PROT_EXEC));
508 #undef S
509 	    remove_trailing_or(tmp);
510 
511     }
512     break;
513 
514   case Mmapflags:
515     {
516 #define S(a)	((args[sc->offset] & a) ? #a "|" : "")
517 	    asprintf(&tmp, "(0x%lx)%s%s%s%s%s%s%s%s", args[sc->offset],
518 		S(MAP_ANON), S(MAP_FIXED), S(MAP_HASSEMAPHORE),
519 		S(MAP_NOCORE), S(MAP_NOSYNC), S(MAP_PRIVATE),
520 		S(MAP_SHARED), S(MAP_STACK));
521 #undef S
522 
523 	    remove_trailing_or(tmp);
524     }
525     break;
526 
527   case Sockaddr:
528     {
529       struct sockaddr_storage ss;
530       char addr[64];
531       struct sockaddr_in *lsin;
532       struct sockaddr_in6 *lsin6;
533       struct sockaddr_un *sun;
534       struct sockaddr *sa;
535       char *p;
536       u_char *q;
537       int i;
538 
539       if (args[sc->offset] == 0) {
540 	      asprintf(&tmp, "NULL");
541 	      break;
542       }
543 
544       /* yuck: get ss_len */
545       if (get_struct(fd, (void *)args[sc->offset], (void *)&ss,
546 	sizeof(ss.ss_len) + sizeof(ss.ss_family)) == -1)
547 	err(1, "get_struct %p", (void *)args[sc->offset]);
548       /* sockaddr_un never have the length filled in! */
549       if (ss.ss_family == AF_UNIX) {
550 	if (get_struct(fd, (void *)args[sc->offset], (void *)&ss,
551 	  sizeof(*sun))
552 	  == -1)
553 	  err(2, "get_struct %p", (void *)args[sc->offset]);
554       } else {
555 	if (get_struct(fd, (void *)args[sc->offset], (void *)&ss, ss.ss_len)
556 	  == -1)
557 	  err(2, "get_struct %p", (void *)args[sc->offset]);
558       }
559 
560       switch (ss.ss_family) {
561       case AF_INET:
562 	lsin = (struct sockaddr_in *)&ss;
563 	inet_ntop(AF_INET, &lsin->sin_addr, addr, sizeof addr);
564 	asprintf(&tmp, "{ AF_INET %s:%d }", addr, htons(lsin->sin_port));
565 	break;
566       case AF_INET6:
567 	lsin6 = (struct sockaddr_in6 *)&ss;
568 	inet_ntop(AF_INET6, &lsin6->sin6_addr, addr, sizeof addr);
569 	asprintf(&tmp, "{ AF_INET6 [%s]:%d }", addr, htons(lsin6->sin6_port));
570 	break;
571       case AF_UNIX:
572         sun = (struct sockaddr_un *)&ss;
573         asprintf(&tmp, "{ AF_UNIX \"%s\" }", sun->sun_path);
574 	break;
575       default:
576 	sa = (struct sockaddr *)&ss;
577         asprintf(&tmp, "{ sa_len = %d, sa_family = %d, sa_data = {%n%*s } }",
578 	  (int)sa->sa_len, (int)sa->sa_family, &i,
579 	  6 * (int)(sa->sa_len - ((char *)&sa->sa_data - (char *)sa)), "");
580 	if (tmp != NULL) {
581 	  p = tmp + i;
582           for (q = (u_char *)&sa->sa_data; q < (u_char *)sa + sa->sa_len; q++)
583             p += sprintf(p, " %#02x,", *q);
584 	}
585       }
586     }
587     break;
588   case Sigaction:
589     {
590       struct sigaction sa;
591       char *hand;
592       const char *h;
593 #define SA_KNOWN_FLAGS \
594 	(SA_ONSTACK | SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | \
595 	 SA_NOCLDWAIT | SA_SIGINFO)
596 
597 
598       if (get_struct(fd, (void *)args[sc->offset], &sa, sizeof(sa)) != -1) {
599 
600 	asprintf(&hand, "%p", sa.sa_handler);
601 	if (sa.sa_handler == SIG_DFL)
602 	  h = "SIG_DFL";
603 	else if (sa.sa_handler == SIG_IGN)
604 	  h = "SIG_IGN";
605 	else
606 	  h = hand;
607 	asprintf(&tmp, "{ %s 0x%x%s%s%s%s%s%s%s ss_t }",
608 	    h,
609 	    sa.sa_flags & ~SA_KNOWN_FLAGS,
610 	    sa.sa_flags & SA_ONSTACK ? "" : "|ONSTACK",
611 	    sa.sa_flags & SA_RESTART ? "" : "|RESTART",
612 	    sa.sa_flags & SA_RESETHAND ? "" : "|RESETHAND",
613 	    sa.sa_flags & SA_NOCLDSTOP ? "" : "|NOCLDSTOP",
614 	    sa.sa_flags & SA_NODEFER ? "" : "|NODEFER",
615 	    sa.sa_flags & SA_NOCLDWAIT ? "" : "|NOCLDWAIT",
616 	    sa.sa_flags & SA_SIGINFO ? "" : "|SIGINFO");
617 	free(hand);
618       } else
619 	asprintf(&tmp, "0x%lx", args[sc->offset]);
620 
621     }
622     break;
623   }
624   return tmp;
625 }
626 
627 #define timespecsubt(tvp, uvp, vvp)					\
628 	do {								\
629 		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
630 		(vvp)->tv_nsec = (tvp)->tv_nsec - (uvp)->tv_nsec;	\
631 		if ((vvp)->tv_nsec < 0) {				\
632 			(vvp)->tv_sec--;				\
633 			(vvp)->tv_nsec += 1000000000;			\
634 		}							\
635 	} while (0)
636 
637 /*
638  * print_syscall
639  * Print (to outfile) the system call and its arguments.  Note that
640  * nargs is the number of arguments (not the number of words; this is
641  * potentially confusing, I know).
642  */
643 
644 void
645 print_syscall(struct trussinfo *trussinfo, const char *name, int nargs, char **s_args) {
646   int i;
647   int len = 0;
648   struct timespec timediff;
649 
650   if (trussinfo->flags & FOLLOWFORKS)
651     len += fprintf(trussinfo->outfile, "%5d: ", trussinfo->pid);
652 
653   if (name != NULL && (!strcmp(name, "execve") || !strcmp(name, "exit"))) {
654     clock_gettime(CLOCK_REALTIME, &trussinfo->after);
655   }
656 
657   if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
658     timespecsubt(&trussinfo->after, &trussinfo->start_time, &timediff);
659     len += fprintf(trussinfo->outfile, "%ld.%09ld ",
660 		   (long)timediff.tv_sec, timediff.tv_nsec);
661   }
662 
663   if (trussinfo->flags & RELATIVETIMESTAMPS) {
664     timespecsubt(&trussinfo->after, &trussinfo->before, &timediff);
665     len += fprintf(trussinfo->outfile, "%ld.%09ld ",
666 		   (long)timediff.tv_sec, timediff.tv_nsec);
667   }
668 
669   len += fprintf(trussinfo->outfile, "%s(", name);
670 
671   for (i = 0; i < nargs; i++) {
672     if (s_args[i])
673       len += fprintf(trussinfo->outfile, "%s", s_args[i]);
674     else
675       len += fprintf(trussinfo->outfile, "<missing argument>");
676     len += fprintf(trussinfo->outfile, "%s", i < (nargs - 1) ? "," : "");
677   }
678   len += fprintf(trussinfo->outfile, ")");
679   for (i = 0; i < 6 - (len / 8); i++)
680 	fprintf(trussinfo->outfile, "\t");
681 }
682 
683 void
684 print_syscall_ret(struct trussinfo *trussinfo, const char *name, int nargs,
685     char **s_args, int errorp, long retval)
686 {
687   print_syscall(trussinfo, name, nargs, s_args);
688   if (errorp) {
689     fprintf(trussinfo->outfile, " ERR#%ld '%s'\n", retval, strerror(retval));
690   } else {
691     fprintf(trussinfo->outfile, " = %ld (0x%lx)\n", retval, retval);
692   }
693 }
694