xref: /freebsd/usr.bin/truss/syscalls.c (revision 2357939bc239bd5334a169b62313806178dd8f30)
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 #define COMPAT_SUNOS
55 #include <signal.h>
56 #include <stdint.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <time.h>
61 #include <unistd.h>
62 
63 #include "truss.h"
64 #include "extern.h"
65 #include "syscall.h"
66 
67 /*
68  * This should probably be in its own file.
69  */
70 
71 struct syscall syscalls[] = {
72 	{ "fcntl", 1, 3,
73 	  { { Int, 0 } , { Fcntl, 1 }, { Hex, 2 }}},
74 	{ "readlink", 1, 3,
75 	  { { String, 0 } , { String | OUT, 1 }, { Int, 2 }}},
76 	{ "lseek", 2, 3,
77 	  { { Int, 0 }, {Quad, 2 }, { Int, 4 }}},
78 	{ "mmap", 2, 6,
79 	  { { Ptr, 0 }, {Int, 1}, {Mprot, 2}, {Mmapflags, 3}, {Int, 4}, {Quad, 6}}},
80 	{ "mprotect", 1, 3,
81 	  { { Ptr, 0 }, {Int, 1}, {Mprot, 2}}},
82 	{ "open", 1, 3,
83 	  { { String | IN, 0} , { Hex, 1}, {Octal, 2}}},
84 	{ "linux_open", 1, 3,
85 	  { { String, 0 }, { Hex, 1}, { Octal, 2 }}},
86 	{ "close", 1, 1,
87 	  { { Int, 0 } } },
88 	{ "link", 0, 2,
89 	  { { String, 0 }, { String, 1 }}},
90 	{ "unlink", 0, 1,
91 	  { { String, 0 }}},
92 	{ "chdir", 0, 1,
93 	  { { String, 0 }}},
94 	{ "mknod", 0, 3,
95 	  { { String, 0 }, { Octal, 1 }, { Int, 3 }}},
96 	{ "chmod", 0, 2,
97 	  { { String, 0 }, { Octal, 1 }}},
98 	{ "chown", 0, 3,
99 	  { { String, 0 }, { Int, 1 }, { Int, 2 }}},
100 	{ "mount", 0, 4,
101 	  { { String, 0 }, { String, 1 }, { Int, 2 }, { Ptr, 3 }}},
102 	{ "umount", 0, 2,
103 	  { { String, 0 }, { Int, 2 }}},
104 	{ "fstat", 1, 2,
105 	  { { Int, 0},  {Ptr | OUT , 1 }}},
106 	{ "stat", 1, 2,
107 	  { { String | IN, 0 }, { Ptr | OUT, 1 }}},
108 	{ "lstat", 1, 2,
109 	  { { String | IN, 0 }, { Ptr | OUT, 1 }}},
110 	{ "linux_newstat", 1, 2,
111 	  { { String | IN, 0 }, { Ptr | OUT, 1 }}},
112 	{ "linux_newfstat", 1, 2,
113 	  { { Int, 0 }, { Ptr | OUT, 1 }}},
114 	{ "write", 1, 3,
115 	  { { Int, 0 }, { Ptr | IN, 1 }, { Int, 2 }}},
116 	{ "ioctl", 1, 3,
117 	  { { Int, 0 }, { Ioctl, 1 }, { Hex, 2 }}},
118 	{ "break", 1, 1, { { Hex, 0 }}},
119 	{ "exit", 0, 1, { { Hex, 0 }}},
120 	{ "access", 1, 2, { { String | IN, 0 }, { Int, 1 }}},
121 	{ "sigaction", 1, 3,
122 	  { { Signal, 0 }, { Sigaction | IN, 1 }, { Sigaction | OUT, 2 }}},
123 	{ "accept", 1, 3,
124 	  { { Hex, 0 }, { Sockaddr | OUT, 1 }, { Ptr | OUT, 2 } } },
125 	{ "bind", 1, 3,
126 	  { { Hex, 0 }, { Sockaddr | IN, 1 }, { Int, 2 } } },
127 	{ "connect", 1, 3,
128 	  { { Hex, 0 }, { Sockaddr | IN, 1 }, { Int, 2 } } },
129 	{ "getpeername", 1, 3,
130 	  { { Hex, 0 }, { Sockaddr | OUT, 1 }, { Ptr | OUT, 2 } } },
131 	{ "getsockname", 1, 3,
132 	  { { Hex, 0 }, { Sockaddr | OUT, 1 }, { Ptr | OUT, 2 } } },
133 	{ "recvfrom", 1, 6,
134 	  { { Hex, 0 }, { Ptr | IN, 1 }, { Int, 3 }, { Hex, 3 }, { Sockaddr | OUT, 4 }, { Ptr | OUT, 5 } } },
135 	{ "sendto", 1, 6,
136 	  { { Hex, 0 }, { Ptr | IN, 1 }, { Int, 3 }, { Hex, 3 }, { Sockaddr | IN, 4 }, { Ptr | IN, 5 } } },
137 	{ "execve", 1, 3,
138 	  { { String | IN, 0 }, { StringArray | IN, 1 }, { StringArray | IN, 2 } } },
139 	{ "linux_execve", 1, 3,
140 	  { { String | IN, 0 }, { StringArray | IN, 1 }, { StringArray | IN, 2 } } },
141 	{ "kldload", 0, 1, { { String | IN, 0 }}},
142 	{ "kldunload", 0, 1, { { Int, 0 }}},
143 	{ "kldfind", 0, 1, { { String | IN, 0 }}},
144 	{ "kldnext", 0, 1, { { Int, 0 }}},
145 	{ "kldstat", 0, 2, { { Int, 0 }, { Ptr, 1 }}},
146 	{ "kldfirstmod", 0, 1, { { Int, 0 }}},
147 	{ "nanosleep", 0, 1, { { Timespec, 0 }}},
148 	{ "select", 1, 5, { { Int, 0 }, { Fd_set, 1 }, { Fd_set, 2 }, { Fd_set, 3 }, { Timeval, 4 }}},
149 	{ "poll", 1, 3, { { Pollfd, 0 }, { Int, 1 }, { Int, 2 }}},
150 	{ "gettimeofday", 1, 2, { { Timeval | OUT, 0 }, { Ptr, 1 }}},
151 	{ "clock_gettime", 1, 2, { { Int, 0 }, { Timeval | OUT, 1 }}},
152 	{ "recvfrom", 1, 6, { { Int, 0 }, { Ptr | OUT, 1 }, { Int, 2 }, { Int, 3 }, { Sockaddr | OUT, 4}, {Ptr | OUT, 5}}},
153 	{ "getitimer", 1, 2, { { Int, 0 }, { Itimerval | OUT, 2 }}},
154 	{ "setitimer", 1, 3, { { Int, 0 }, { Itimerval, 1} , { Itimerval | OUT, 2 }}},
155 	{ 0, 0, 0, { { 0, 0 }}},
156 };
157 
158 /*
159  * If/when the list gets big, it might be desirable to do it
160  * as a hash table or binary search.
161  */
162 
163 struct syscall *
164 get_syscall(const char *name) {
165 	struct syscall *sc = syscalls;
166 
167 	while (sc->name) {
168 		if (!strcmp(name, sc->name))
169 			return sc;
170 		sc++;
171 	}
172 	return NULL;
173 }
174 
175 /*
176  * get_struct
177  *
178  * Copy a fixed amount of bytes from the process.
179  */
180 
181 static int
182 get_struct(int procfd, void *offset, void *buf, int len) {
183 
184 	if (pread(procfd, buf, len, (uintptr_t)offset) != len)
185 		return -1;
186 	return 0;
187 }
188 
189 /*
190  * get_string
191  * Copy a string from the process.  Note that it is
192  * expected to be a C string, but if max is set, it will
193  * only get that much.
194  */
195 
196 char *
197 get_string(int procfd, void *offset, int max) {
198 	char *buf;
199 	int size, len, c, fd;
200 	FILE *p;
201 
202 	if ((fd = dup(procfd)) == -1)
203 		err(1, "dup");
204 	if ((p = fdopen(fd, "r")) == NULL)
205 		err(1, "fdopen");
206 	buf = malloc( size = (max ? max : 64 ) );
207 	len = 0;
208 	buf[0] = 0;
209 	if (fseeko(p, (uintptr_t)offset, SEEK_SET) == 0) {
210 		while ((c = fgetc(p)) != EOF) {
211 			buf[len++] = c;
212 			if (c == 0 || len == max) {
213 				buf[len] = 0;
214 				break;
215 			}
216 			if (len == size) {
217 				char *tmp;
218 				tmp = realloc(buf, size+64);
219 				if (tmp == NULL) {
220 					buf[len] = 0;
221 					break;
222 				}
223 				size += 64;
224 				buf = tmp;
225 			}
226 		}
227 	}
228 	fclose(p);
229 	return (buf);
230 }
231 
232 
233 /*
234  * Gag.  This is really unportable.  Multiplication is more portable.
235  * But slower, from the code I saw.
236  */
237 
238 static long long
239 make_quad(unsigned long p1, unsigned long p2) {
240   union {
241     long long ll;
242     unsigned long l[2];
243   } t;
244   t.l[0] = p1;
245   t.l[1] = p2;
246   return t.ll;
247 }
248 
249 /*
250  * Remove a trailing '|' in a string, useful for fixup after decoding
251  * a "flags" argument.
252  */
253 
254 void
255 remove_trailing_or(char *str)
256 {
257 
258 	if (str != NULL && (str = rindex(str, '|')) != NULL && str[1] == '\0')
259 		*str = '\0';
260 }
261 
262 /*
263  * print_arg
264  * Converts a syscall argument into a string.  Said string is
265  * allocated via malloc(), so needs to be free()'d.  The file
266  * descriptor is for the process' memory (via /proc), and is used
267  * to get any data (where the argument is a pointer).  sc is
268  * a pointer to the syscall description (see above); args is
269  * an array of all of the system call arguments.
270  */
271 
272 char *
273 print_arg(int fd, struct syscall_args *sc, unsigned long *args) {
274   char *tmp = NULL;
275   switch (sc->type & ARG_MASK) {
276   case Hex:
277     asprintf(&tmp, "0x%lx", args[sc->offset]);
278     break;
279   case Octal:
280     asprintf(&tmp, "0%lo", args[sc->offset]);
281     break;
282   case Int:
283     asprintf(&tmp, "%ld", args[sc->offset]);
284     break;
285   case String:
286     {
287       char *tmp2;
288       tmp2 = get_string(fd, (void*)args[sc->offset], 0);
289       asprintf(&tmp, "\"%s\"", tmp2);
290       free(tmp2);
291     }
292   break;
293   case StringArray:
294     {
295       int num, size, i;
296       char *tmp2;
297       char *string;
298       char *strarray[100];	/* XXX This is ugly. */
299 
300       if (get_struct(fd, (void *)args[sc->offset], (void *)&strarray,
301                      sizeof(strarray)) == -1) {
302 	err(1, "get_struct %p", (void *)args[sc->offset]);
303       }
304       num = 0;
305       size = 0;
306 
307       /* Find out how large of a buffer we'll need. */
308       while (strarray[num] != NULL) {
309 	string = get_string(fd, (void*)strarray[num], 0);
310         size += strlen(string);
311 	free(string);
312 	num++;
313       }
314       size += 4 + (num * 4);
315       tmp = (char *)malloc(size);
316       tmp2 = tmp;
317 
318       tmp2 += sprintf(tmp2, " [");
319       for (i = 0; i < num; i++) {
320 	string = get_string(fd, (void*)strarray[i], 0);
321         tmp2 += sprintf(tmp2, " \"%s\"%c", string, (i+1 == num) ? ' ' : ',');
322 	free(string);
323       }
324       tmp2 += sprintf(tmp2, "]");
325     }
326   break;
327   case Quad:
328     {
329       unsigned long long t;
330       unsigned long l1, l2;
331       l1 = args[sc->offset];
332       l2 = args[sc->offset+1];
333       t = make_quad(l1, l2);
334       asprintf(&tmp, "0x%qx", t);
335       break;
336     }
337   case Ptr:
338     asprintf(&tmp, "0x%lx", args[sc->offset]);
339     break;
340   case Ioctl:
341     {
342       const char *temp = ioctlname(args[sc->offset]);
343       if (temp)
344 	tmp = strdup(temp);
345       else
346 	asprintf(&tmp, "0x%lx", args[sc->offset]);
347     }
348     break;
349   case Timespec:
350     {
351       struct timespec ts;
352       if (get_struct(fd, (void *)args[sc->offset], &ts, sizeof(ts)) != -1)
353 	asprintf(&tmp, "{%jd %jd}", (intmax_t)ts.tv_sec, (intmax_t)ts.tv_nsec);
354       else
355 	asprintf(&tmp, "0x%lx", args[sc->offset]);
356     }
357     break;
358   case Timeval:
359     {
360       struct timeval tv;
361       if (get_struct(fd, (void *)args[sc->offset], &tv, sizeof(tv)) != -1)
362 	asprintf(&tmp, "{%jd %jd}", (intmax_t)tv.tv_sec, (intmax_t)tv.tv_usec);
363       else
364 	asprintf(&tmp, "0x%lx", args[sc->offset]);
365     }
366     break;
367   case Itimerval:
368     {
369       struct itimerval itv;
370       if (get_struct(fd, (void *)args[sc->offset], &itv, sizeof(itv)) != -1)
371 	asprintf(&tmp, "{%jd %jd, %jd %jd}",
372 	    (intmax_t)itv.it_interval.tv_sec,
373 	    (intmax_t)itv.it_interval.tv_usec,
374 	    (intmax_t)itv.it_value.tv_sec,
375 	    (intmax_t)itv.it_value.tv_usec);
376       else
377 	asprintf(&tmp, "0x%lx", args[sc->offset]);
378     }
379     break;
380   case Pollfd:
381     {
382       /*
383        * XXX: A Pollfd argument expects the /next/ syscall argument to be
384        * the number of fds in the array. This matches the poll syscall.
385        */
386       struct pollfd *pfd;
387       int numfds = args[sc->offset+1];
388       int bytes = sizeof(struct pollfd) * numfds;
389       int i, tmpsize, u, used;
390       const int per_fd = 100;
391 
392       if ((pfd = malloc(bytes)) == NULL)
393 	err(1, "Cannot malloc %d bytes for pollfd array", bytes);
394       if (get_struct(fd, (void *)args[sc->offset], pfd, bytes) != -1) {
395 
396 	used = 0;
397 	tmpsize = 1 + per_fd * numfds + 2;
398 	if ((tmp = malloc(tmpsize)) == NULL)
399 	  err(1, "Cannot alloc %d bytes for poll output", tmpsize);
400 
401 	tmp[used++] = '{';
402 	for (i = 0; i < numfds; i++) {
403 #define POLLKNOWN_EVENTS \
404 	(POLLIN | POLLPRI | POLLOUT | POLLERR | POLLHUP | POLLNVAL | \
405 	 POLLRDNORM |POLLRDBAND | POLLWRBAND | POLLINIGNEOF)
406 
407 	  u += snprintf(tmp + used, per_fd,
408 	    "%s%d 0x%hx%s%s%s%s%s%s%s%s%s ",
409 	    i > 0 ? " " : "",
410 	    pfd[i].fd,
411 	    pfd[i].events & ~POLLKNOWN_EVENTS,
412 	    pfd[i].events & POLLIN ? "" : "|IN",
413 	    pfd[i].events & POLLPRI ? "" : "|PRI",
414 	    pfd[i].events & POLLOUT ? "" : "|OUT",
415 	    pfd[i].events & POLLERR ? "" : "|ERR",
416 	    pfd[i].events & POLLHUP ? "" : "|HUP",
417 	    pfd[i].events & POLLNVAL ? "" : "|NVAL",
418 	    pfd[i].events & POLLRDNORM ? "" : "|RDNORM",
419 	    pfd[i].events & POLLRDBAND ? "" : "|RDBAND",
420 	    pfd[i].events & POLLWRBAND ? "" : "|WRBAND");
421 	  if (u > 0)
422 	    used += u < per_fd ? u : per_fd;
423 	}
424 	tmp[used++] = '}';
425 	tmp[used++] = '\0';
426       } else
427 	asprintf(&tmp, "0x%lx", args[sc->offset]);
428       free(pfd);
429     }
430     break;
431   case Fd_set:
432     {
433       /*
434        * XXX: A Fd_set argument expects the /first/ syscall argument to be
435        * the number of fds in the array.  This matches the select syscall.
436        */
437       fd_set *fds;
438       int numfds = args[0];
439       int bytes = _howmany(numfds, _NFDBITS) * _NFDBITS;
440       int i, tmpsize, u, used;
441       const int per_fd = 20;
442 
443       if ((fds = malloc(bytes)) == NULL)
444 	err(1, "Cannot malloc %d bytes for fd_set array", bytes);
445       if (get_struct(fd, (void *)args[sc->offset], fds, bytes) != -1) {
446 	used = 0;
447 	tmpsize = 1 + numfds * per_fd + 2;
448 	if ((tmp = malloc(tmpsize)) == NULL)
449 	  err(1, "Cannot alloc %d bytes for fd_set output", tmpsize);
450 
451 	tmp[used++] = '{';
452 	for (i = 0; i < numfds; i++) {
453 	  if (FD_ISSET(i, fds)) {
454 	    u = snprintf(tmp + used, per_fd, "%d ", i);
455 	    if (u > 0)
456 	      used += u < per_fd ? u : per_fd;
457 	  }
458 	}
459 	if (tmp[used-1] == ' ')
460 		used--;
461 	tmp[used++] = '}';
462 	tmp[used++] = '\0';
463       } else
464 	asprintf(&tmp, "0x%lx", args[sc->offset]);
465       free(fds);
466     }
467     break;
468   case Signal:
469     {
470       long sig;
471 
472       sig = args[sc->offset];
473       if (sig > 0 && sig < NSIG) {
474 	int i;
475 	asprintf(&tmp, "sig%s", sys_signame[sig]);
476 	for (i = 0; tmp[i] != '\0'; ++i)
477 	  tmp[i] = toupper(tmp[i]);
478       } else
479         asprintf(&tmp, "%ld", sig);
480     }
481     break;
482   case Fcntl:
483     {
484 	switch (args[sc->offset]) {
485 #define S(a)	case a: tmp = strdup(#a); break;
486 	S(F_DUPFD);
487 	S(F_GETFD);
488 	S(F_SETFD);
489 	S(F_GETFL);
490 	S(F_SETFL);
491 	S(F_GETOWN);
492 	S(F_SETOWN);
493 	S(F_GETLK);
494 	S(F_SETLK);
495 	S(F_SETLKW);
496 #undef S
497 	}
498 	if (tmp == NULL)
499     		asprintf(&tmp, "0x%lx", args[sc->offset]);
500     }
501     break;
502 
503   case Mprot:
504     {
505 
506 #define S(a)	((args[sc->offset] & a) ? #a "|" : "")
507 	    asprintf(&tmp, "(0x%lx)%s%s%s%s", args[sc->offset],
508 		S(PROT_NONE), S(PROT_READ), S(PROT_WRITE), S(PROT_EXEC));
509 #undef S
510 	    remove_trailing_or(tmp);
511 
512     }
513     break;
514 
515   case Mmapflags:
516     {
517 #define S(a)	((args[sc->offset] & a) ? #a "|" : "")
518 	    asprintf(&tmp, "(0x%lx)%s%s%s%s%s%s%s%s", args[sc->offset],
519 		S(MAP_ANON), S(MAP_FIXED), S(MAP_HASSEMAPHORE),
520 		S(MAP_NOCORE), S(MAP_NOSYNC), S(MAP_PRIVATE),
521 		S(MAP_SHARED), S(MAP_STACK));
522 #undef S
523 
524 	    remove_trailing_or(tmp);
525     }
526     break;
527 
528   case Sockaddr:
529     {
530       struct sockaddr_storage ss;
531       char addr[64];
532       struct sockaddr_in *lsin;
533       struct sockaddr_in6 *lsin6;
534       struct sockaddr_un *sun;
535       struct sockaddr *sa;
536       char *p;
537       u_char *q;
538       int i;
539 
540       if (args[sc->offset] == 0) {
541 	      asprintf(&tmp, "NULL");
542 	      break;
543       }
544 
545       /* yuck: get ss_len */
546       if (get_struct(fd, (void *)args[sc->offset], (void *)&ss,
547 	sizeof(ss.ss_len) + sizeof(ss.ss_family)) == -1)
548 	err(1, "get_struct %p", (void *)args[sc->offset]);
549       /* sockaddr_un never have the length filled in! */
550       if (ss.ss_family == AF_UNIX) {
551 	if (get_struct(fd, (void *)args[sc->offset], (void *)&ss,
552 	  sizeof(*sun))
553 	  == -1)
554 	  err(2, "get_struct %p", (void *)args[sc->offset]);
555       } else {
556 	if (get_struct(fd, (void *)args[sc->offset], (void *)&ss, ss.ss_len)
557 	  == -1)
558 	  err(2, "get_struct %p", (void *)args[sc->offset]);
559       }
560 
561       switch (ss.ss_family) {
562       case AF_INET:
563 	lsin = (struct sockaddr_in *)&ss;
564 	inet_ntop(AF_INET, &lsin->sin_addr, addr, sizeof addr);
565 	asprintf(&tmp, "{ AF_INET %s:%d }", addr, htons(lsin->sin_port));
566 	break;
567       case AF_INET6:
568 	lsin6 = (struct sockaddr_in6 *)&ss;
569 	inet_ntop(AF_INET6, &lsin6->sin6_addr, addr, sizeof addr);
570 	asprintf(&tmp, "{ AF_INET6 [%s]:%d }", addr, htons(lsin6->sin6_port));
571 	break;
572       case AF_UNIX:
573         sun = (struct sockaddr_un *)&ss;
574         asprintf(&tmp, "{ AF_UNIX \"%s\" }", sun->sun_path);
575 	break;
576       default:
577 	sa = (struct sockaddr *)&ss;
578         asprintf(&tmp, "{ sa_len = %d, sa_family = %d, sa_data = {%n%*s } }",
579 	  (int)sa->sa_len, (int)sa->sa_family, &i,
580 	  6 * (int)(sa->sa_len - ((char *)&sa->sa_data - (char *)sa)), "");
581 	if (tmp != NULL) {
582 	  p = tmp + i;
583           for (q = (u_char *)&sa->sa_data; q < (u_char *)sa + sa->sa_len; q++)
584             p += sprintf(p, " %#02x,", *q);
585 	}
586       }
587     }
588     break;
589   case Sigaction:
590     {
591       struct sigaction sa;
592       char *hand;
593       const char *h;
594 #define SA_KNOWN_FLAGS \
595 	(SA_ONSTACK | SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | \
596 	 SA_NOCLDWAIT | SA_SIGINFO | SA_USERTRAMP)
597 
598 
599       if (get_struct(fd, (void *)args[sc->offset], &sa, sizeof(sa)) != -1) {
600 
601 	asprintf(&hand, "%p", sa.sa_handler);
602 	if (sa.sa_handler == SIG_DFL)
603 	  h = "SIG_DFL";
604 	else if (sa.sa_handler == SIG_IGN)
605 	  h = "SIG_IGN";
606 	else
607 	  h = hand;
608 	asprintf(&tmp, "{ %s 0x%x%s%s%s%s%s%s%s%s ss_t }",
609 	    h,
610 	    sa.sa_flags & ~SA_KNOWN_FLAGS,
611 	    sa.sa_flags & SA_ONSTACK ? "" : "|ONSTACK",
612 	    sa.sa_flags & SA_RESTART ? "" : "|RESTART",
613 	    sa.sa_flags & SA_RESETHAND ? "" : "|RESETHAND",
614 	    sa.sa_flags & SA_NOCLDSTOP ? "" : "|NOCLDSTOP",
615 	    sa.sa_flags & SA_NODEFER ? "" : "|NODEFER",
616 	    sa.sa_flags & SA_NOCLDWAIT ? "" : "|NOCLDWAIT",
617 	    sa.sa_flags & SA_SIGINFO ? "" : "|SIGINFO",
618 	    sa.sa_flags & SA_USERTRAMP ? "" : "|USERTRAMP");
619 	free(hand);
620       } else
621 	asprintf(&tmp, "0x%lx", args[sc->offset]);
622 
623     }
624     break;
625   }
626   return tmp;
627 }
628 
629 #define timespecsubt(tvp, uvp, vvp)					\
630 	do {								\
631 		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
632 		(vvp)->tv_nsec = (tvp)->tv_nsec - (uvp)->tv_nsec;	\
633 		if ((vvp)->tv_nsec < 0) {				\
634 			(vvp)->tv_sec--;				\
635 			(vvp)->tv_nsec += 1000000000;			\
636 		}							\
637 	} while (0)
638 
639 /*
640  * print_syscall
641  * Print (to outfile) the system call and its arguments.  Note that
642  * nargs is the number of arguments (not the number of words; this is
643  * potentially confusing, I know).
644  */
645 
646 void
647 print_syscall(struct trussinfo *trussinfo, const char *name, int nargs, char **s_args) {
648   int i;
649   int len = 0;
650   struct timespec timediff;
651 
652   if (trussinfo->flags & FOLLOWFORKS)
653     len += fprintf(trussinfo->outfile, "%5d: ", trussinfo->pid);
654 
655   if (name != NULL && (!strcmp(name, "execve") || !strcmp(name, "exit"))) {
656     clock_gettime(CLOCK_REALTIME, &trussinfo->after);
657   }
658 
659   if (trussinfo->flags & ABSOLUTETIMESTAMPS) {
660     timespecsubt(&trussinfo->after, &trussinfo->start_time, &timediff);
661     len += fprintf(trussinfo->outfile, "%ld.%09ld ",
662 		   (long)timediff.tv_sec, timediff.tv_nsec);
663   }
664 
665   if (trussinfo->flags & RELATIVETIMESTAMPS) {
666     timespecsubt(&trussinfo->after, &trussinfo->before, &timediff);
667     len += fprintf(trussinfo->outfile, "%ld.%09ld ",
668 		   (long)timediff.tv_sec, timediff.tv_nsec);
669   }
670 
671   len += fprintf(trussinfo->outfile, "%s(", name);
672 
673   for (i = 0; i < nargs; i++) {
674     if (s_args[i])
675       len += fprintf(trussinfo->outfile, "%s", s_args[i]);
676     else
677       len += fprintf(trussinfo->outfile, "<missing argument>");
678     len += fprintf(trussinfo->outfile, "%s", i < (nargs - 1) ? "," : "");
679   }
680   len += fprintf(trussinfo->outfile, ")");
681   for (i = 0; i < 6 - (len / 8); i++)
682 	fprintf(trussinfo->outfile, "\t");
683 }
684 
685 void
686 print_syscall_ret(struct trussinfo *trussinfo, const char *name, int nargs,
687     char **s_args, int errorp, long retval)
688 {
689   print_syscall(trussinfo, name, nargs, s_args);
690   if (errorp) {
691     fprintf(trussinfo->outfile, " ERR#%ld '%s'\n", retval, strerror(retval));
692   } else {
693     fprintf(trussinfo->outfile, " = %ld (0x%lx)\n", retval, retval);
694   }
695 }
696