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1 /*
2  * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
3  * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
4  * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
5  * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
6  * Copyright (c) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
7  *                     Linux for s390 port by D.J. Barrow
8  *                    <barrow_dj@mail.yahoo.com,djbarrow@de.ibm.com>
9  * Copyright (c) 1999-2017 The strace developers.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. The name of the author may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  */
34
35 #include "defs.h"
36 #include "native_defs.h"
37 #include "nsig.h"
38 #include <sys/param.h>
39
40 /* for struct iovec */
41 #include <sys/uio.h>
42
43 /* for __X32_SYSCALL_BIT */
44 #include <asm/unistd.h>
45
46 #include "regs.h"
47 #include "ptrace.h"
48
49 #if defined(SPARC64)
50 # undef PTRACE_GETREGS
51 # define PTRACE_GETREGS PTRACE_GETREGS64
52 # undef PTRACE_SETREGS
53 # define PTRACE_SETREGS PTRACE_SETREGS64
54 #endif
55
56 #if defined SPARC64
57 # include <asm/psrcompat.h>
58 #elif defined SPARC
59 # include <asm/psr.h>
60 #endif
61
62 #ifdef IA64
63 # include <asm/rse.h>
64 #endif
65
66 #ifndef NT_PRSTATUS
67 # define NT_PRSTATUS 1
68 #endif
69
70 #include "syscall.h"
71
72 /* Define these shorthand notations to simplify the syscallent files. */
73 #define TD TRACE_DESC
74 #define TF TRACE_FILE
75 #define TI TRACE_IPC
76 #define TN TRACE_NETWORK
77 #define TP TRACE_PROCESS
78 #define TS TRACE_SIGNAL
79 #define TM TRACE_MEMORY
80 #define TST TRACE_STAT
81 #define TLST TRACE_LSTAT
82 #define TFST TRACE_FSTAT
83 #define TSTA TRACE_STAT_LIKE
84 #define TSF TRACE_STATFS
85 #define TFSF TRACE_FSTATFS
86 #define TSFA TRACE_STATFS_LIKE
87 #define NF SYSCALL_NEVER_FAILS
88 #define MA MAX_ARGS
89 #define SI STACKTRACE_INVALIDATE_CACHE
90 #define SE STACKTRACE_CAPTURE_ON_ENTER
91 #define CST COMPAT_SYSCALL_TYPES
92
93 #define SEN(syscall_name) SEN_ ## syscall_name, SYS_FUNC_NAME(sys_ ## syscall_name)
94
95 const struct_sysent sysent0[] = {
96 #include "syscallent.h"
97 };
98
99 #if SUPPORTED_PERSONALITIES > 1
100 # include PERSONALITY1_INCLUDE_FUNCS
101 static const struct_sysent sysent1[] = {
102 # include "syscallent1.h"
103 };
104 #endif
105
106 #if SUPPORTED_PERSONALITIES > 2
107 # include PERSONALITY2_INCLUDE_FUNCS
108 static const struct_sysent sysent2[] = {
109 # include "syscallent2.h"
110 };
111 #endif
112
113 /* Now undef them since short defines cause wicked namespace pollution. */
114 #undef SEN
115 #undef TD
116 #undef TF
117 #undef TI
118 #undef TN
119 #undef TP
120 #undef TS
121 #undef TM
122 #undef TST
123 #undef TLST
124 #undef TFST
125 #undef TSTA
126 #undef TSF
127 #undef TFSF
128 #undef TSFA
129 #undef NF
130 #undef MA
131 #undef SI
132 #undef SE
133 #undef CST
134
135 /*
136  * `ioctlent[012].h' files are automatically generated by the auxiliary
137  * program `ioctlsort', such that the list is sorted by the `code' field.
138  * This has the side-effect of resolving the _IO.. macros into
139  * plain integers, eliminating the need to include here everything
140  * in "/usr/include".
141  */
142
143 const char *const errnoent0[] = {
144 #include "errnoent.h"
145 };
146 const char *const signalent0[] = {
147 #include "signalent.h"
148 };
149 const struct_ioctlent ioctlent0[] = {
150 #include "ioctlent0.h"
151 };
152
153 #if SUPPORTED_PERSONALITIES > 1
154 static const char *const errnoent1[] = {
155 # include "errnoent1.h"
156 };
157 static const char *const signalent1[] = {
158 # include "signalent1.h"
159 };
160 static const struct_ioctlent ioctlent1[] = {
161 # include "ioctlent1.h"
162 };
163 # include PERSONALITY0_INCLUDE_PRINTERS_DECLS
164 static const struct_printers printers0 = {
165 # include PERSONALITY0_INCLUDE_PRINTERS_DEFS
166 };
167 # include PERSONALITY1_INCLUDE_PRINTERS_DECLS
168 static const struct_printers printers1 = {
169 # include PERSONALITY1_INCLUDE_PRINTERS_DEFS
170 };
171 #endif
172
173 #if SUPPORTED_PERSONALITIES > 2
174 static const char *const errnoent2[] = {
175 # include "errnoent2.h"
176 };
177 static const char *const signalent2[] = {
178 # include "signalent2.h"
179 };
180 static const struct_ioctlent ioctlent2[] = {
181 # include "ioctlent2.h"
182 };
183 # include PERSONALITY2_INCLUDE_PRINTERS_DECLS
184 static const struct_printers printers2 = {
185 # include PERSONALITY2_INCLUDE_PRINTERS_DEFS
186 };
187 #endif
188
189 enum {
190         nsyscalls0 = ARRAY_SIZE(sysent0)
191 #if SUPPORTED_PERSONALITIES > 1
192         , nsyscalls1 = ARRAY_SIZE(sysent1)
193 # if SUPPORTED_PERSONALITIES > 2
194         , nsyscalls2 = ARRAY_SIZE(sysent2)
195 # endif
196 #endif
197 };
198
199 enum {
200         nerrnos0 = ARRAY_SIZE(errnoent0)
201 #if SUPPORTED_PERSONALITIES > 1
202         , nerrnos1 = ARRAY_SIZE(errnoent1)
203 # if SUPPORTED_PERSONALITIES > 2
204         , nerrnos2 = ARRAY_SIZE(errnoent2)
205 # endif
206 #endif
207 };
208
209 enum {
210         nsignals0 = ARRAY_SIZE(signalent0)
211 #if SUPPORTED_PERSONALITIES > 1
212         , nsignals1 = ARRAY_SIZE(signalent1)
213 # if SUPPORTED_PERSONALITIES > 2
214         , nsignals2 = ARRAY_SIZE(signalent2)
215 # endif
216 #endif
217 };
218
219 enum {
220         nioctlents0 = ARRAY_SIZE(ioctlent0)
221 #if SUPPORTED_PERSONALITIES > 1
222         , nioctlents1 = ARRAY_SIZE(ioctlent1)
223 # if SUPPORTED_PERSONALITIES > 2
224         , nioctlents2 = ARRAY_SIZE(ioctlent2)
225 # endif
226 #endif
227 };
228
229 #if SUPPORTED_PERSONALITIES > 1
230 const struct_sysent *sysent = sysent0;
231 const char *const *errnoent = errnoent0;
232 const char *const *signalent = signalent0;
233 const struct_ioctlent *ioctlent = ioctlent0;
234 const struct_printers *printers = &printers0;
235 #endif
236
237 unsigned nsyscalls = nsyscalls0;
238 unsigned nerrnos = nerrnos0;
239 unsigned nsignals = nsignals0;
240 unsigned nioctlents = nioctlents0;
241
242 const unsigned int nsyscall_vec[SUPPORTED_PERSONALITIES] = {
243         nsyscalls0,
244 #if SUPPORTED_PERSONALITIES > 1
245         nsyscalls1,
246 #endif
247 #if SUPPORTED_PERSONALITIES > 2
248         nsyscalls2,
249 #endif
250 };
251 const struct_sysent *const sysent_vec[SUPPORTED_PERSONALITIES] = {
252         sysent0,
253 #if SUPPORTED_PERSONALITIES > 1
254         sysent1,
255 #endif
256 #if SUPPORTED_PERSONALITIES > 2
257         sysent2,
258 #endif
259 };
260
261 #if SUPPORTED_PERSONALITIES > 1
262 unsigned current_personality;
263
264 # ifndef current_wordsize
265 unsigned current_wordsize;
266 static const int personality_wordsize[SUPPORTED_PERSONALITIES] = {
267         PERSONALITY0_WORDSIZE,
268         PERSONALITY1_WORDSIZE,
269 # if SUPPORTED_PERSONALITIES > 2
270         PERSONALITY2_WORDSIZE,
271 # endif
272 };
273 # endif
274
275 # ifndef current_klongsize
276 unsigned current_klongsize;
277 static const int personality_klongsize[SUPPORTED_PERSONALITIES] = {
278         PERSONALITY0_KLONGSIZE,
279         PERSONALITY1_KLONGSIZE,
280 #  if SUPPORTED_PERSONALITIES > 2
281         PERSONALITY2_KLONGSIZE,
282 #  endif
283 };
284 # endif
285
286 void
287 set_personality(int personality)
288 {
289         nsyscalls = nsyscall_vec[personality];
290         sysent = sysent_vec[personality];
291
292         switch (personality) {
293         case 0:
294                 errnoent = errnoent0;
295                 nerrnos = nerrnos0;
296                 ioctlent = ioctlent0;
297                 nioctlents = nioctlents0;
298                 signalent = signalent0;
299                 nsignals = nsignals0;
300                 printers = &printers0;
301                 break;
302
303         case 1:
304                 errnoent = errnoent1;
305                 nerrnos = nerrnos1;
306                 ioctlent = ioctlent1;
307                 nioctlents = nioctlents1;
308                 signalent = signalent1;
309                 nsignals = nsignals1;
310                 printers = &printers1;
311                 break;
312
313 # if SUPPORTED_PERSONALITIES > 2
314         case 2:
315                 errnoent = errnoent2;
316                 nerrnos = nerrnos2;
317                 ioctlent = ioctlent2;
318                 nioctlents = nioctlents2;
319                 signalent = signalent2;
320                 nsignals = nsignals2;
321                 printers = &printers2;
322                 break;
323 # endif
324         }
325
326         current_personality = personality;
327 # ifndef current_wordsize
328         current_wordsize = personality_wordsize[personality];
329 # endif
330 # ifndef current_klongsize
331         current_klongsize = personality_klongsize[personality];
332 # endif
333 }
334
335 static void
336 update_personality(struct tcb *tcp, unsigned int personality)
337 {
338         if (personality == current_personality)
339                 return;
340         set_personality(personality);
341
342         if (personality == tcp->currpers)
343                 return;
344         tcp->currpers = personality;
345
346 # undef PERSONALITY_NAMES
347 # if defined POWERPC64
348 #  define PERSONALITY_NAMES {"64 bit", "32 bit"}
349 # elif defined X86_64
350 #  define PERSONALITY_NAMES {"64 bit", "32 bit", "x32"}
351 # elif defined X32
352 #  define PERSONALITY_NAMES {"x32", "32 bit"}
353 # elif defined AARCH64
354 #  define PERSONALITY_NAMES {"64 bit", "32 bit"}
355 # elif defined TILE
356 #  define PERSONALITY_NAMES {"64-bit", "32-bit"}
357 # endif
358 # ifdef PERSONALITY_NAMES
359         if (!qflag) {
360                 static const char *const names[] = PERSONALITY_NAMES;
361                 error_msg("[ Process PID=%d runs in %s mode. ]",
362                           tcp->pid, names[personality]);
363         }
364 # endif
365 }
366 #endif
367
368 #ifdef SYS_socket_subcall
369 static void
370 decode_socket_subcall(struct tcb *tcp)
371 {
372         const int call = tcp->u_arg[0];
373
374         if (call < 1 || call >= SYS_socket_nsubcalls)
375                 return;
376
377         const kernel_ulong_t scno = SYS_socket_subcall + call;
378         const unsigned int nargs = sysent[scno].nargs;
379         uint64_t buf[nargs];
380
381         if (umoven(tcp, tcp->u_arg[1], nargs * current_wordsize, buf) < 0)
382                 return;
383
384         tcp->scno = scno;
385         tcp->qual_flg = qual_flags(scno);
386         tcp->s_ent = &sysent[scno];
387
388         unsigned int i;
389         for (i = 0; i < nargs; ++i)
390                 tcp->u_arg[i] = (sizeof(uint32_t) == current_wordsize)
391                                 ? ((uint32_t *) (void *) buf)[i] : buf[i];
392 }
393 #endif
394
395 #ifdef SYS_ipc_subcall
396 static void
397 decode_ipc_subcall(struct tcb *tcp)
398 {
399         unsigned int call = tcp->u_arg[0];
400         const unsigned int version = call >> 16;
401
402         if (version) {
403 # if defined S390 || defined S390X
404                 return;
405 # else
406 #  ifdef SPARC64
407                 if (current_wordsize == 8)
408                         return;
409 #  endif
410                 set_tcb_priv_ulong(tcp, version);
411                 call &= 0xffff;
412 # endif
413         }
414
415         switch (call) {
416                 case  1: case  2: case  3: case  4:
417                 case 11: case 12: case 13: case 14:
418                 case 21: case 22: case 23: case 24:
419                         break;
420                 default:
421                         return;
422         }
423
424         tcp->scno = SYS_ipc_subcall + call;
425         tcp->qual_flg = qual_flags(tcp->scno);
426         tcp->s_ent = &sysent[tcp->scno];
427
428         const unsigned int n = tcp->s_ent->nargs;
429         unsigned int i;
430         for (i = 0; i < n; i++)
431                 tcp->u_arg[i] = tcp->u_arg[i + 1];
432 }
433 #endif
434
435 #ifdef LINUX_MIPSO32
436 static void
437 decode_mips_subcall(struct tcb *tcp)
438 {
439         if (!scno_is_valid(tcp->u_arg[0]))
440                 return;
441         tcp->scno = tcp->u_arg[0];
442         tcp->qual_flg = qual_flags(tcp->scno);
443         tcp->s_ent = &sysent[tcp->scno];
444         memmove(&tcp->u_arg[0], &tcp->u_arg[1],
445                 sizeof(tcp->u_arg) - sizeof(tcp->u_arg[0]));
446         /*
447          * Fetching the last arg of 7-arg syscalls (fadvise64_64
448          * and sync_file_range) requires additional code,
449          * see linux/mips/get_syscall_args.c
450          */
451         if (tcp->s_ent->nargs == MAX_ARGS) {
452                 if (umoven(tcp,
453                            mips_REG_SP + MAX_ARGS * sizeof(tcp->u_arg[0]),
454                            sizeof(tcp->u_arg[0]),
455                            &tcp->u_arg[MAX_ARGS - 1]) < 0)
456                 tcp->u_arg[MAX_ARGS - 1] = 0;
457         }
458 }
459 #endif /* LINUX_MIPSO32 */
460
461 static void
462 dumpio(struct tcb *tcp)
463 {
464         if (syserror(tcp))
465                 return;
466
467         int fd = tcp->u_arg[0];
468         if (fd < 0)
469                 return;
470
471         if (is_number_in_set(fd, &read_set)) {
472                 switch (tcp->s_ent->sen) {
473                 case SEN_read:
474                 case SEN_pread:
475                 case SEN_recv:
476                 case SEN_recvfrom:
477                 case SEN_mq_timedreceive:
478                         dumpstr(tcp, tcp->u_arg[1], tcp->u_rval);
479                         return;
480                 case SEN_readv:
481                 case SEN_preadv:
482                 case SEN_preadv2:
483                         dumpiov_upto(tcp, tcp->u_arg[2], tcp->u_arg[1],
484                                      tcp->u_rval);
485                         return;
486                 case SEN_recvmsg:
487                         dumpiov_in_msghdr(tcp, tcp->u_arg[1], tcp->u_rval);
488                         return;
489                 case SEN_recvmmsg:
490                         dumpiov_in_mmsghdr(tcp, tcp->u_arg[1]);
491                         return;
492                 }
493         }
494         if (is_number_in_set(fd, &write_set)) {
495                 switch (tcp->s_ent->sen) {
496                 case SEN_write:
497                 case SEN_pwrite:
498                 case SEN_send:
499                 case SEN_sendto:
500                 case SEN_mq_timedsend:
501                         dumpstr(tcp, tcp->u_arg[1], tcp->u_arg[2]);
502                         break;
503                 case SEN_writev:
504                 case SEN_pwritev:
505                 case SEN_pwritev2:
506                 case SEN_vmsplice:
507                         dumpiov_upto(tcp, tcp->u_arg[2], tcp->u_arg[1], -1);
508                         break;
509                 case SEN_sendmsg:
510                         dumpiov_in_msghdr(tcp, tcp->u_arg[1], -1);
511                         break;
512                 case SEN_sendmmsg:
513                         dumpiov_in_mmsghdr(tcp, tcp->u_arg[1]);
514                         break;
515                 }
516         }
517 }
518
519 /*
520  * Shuffle syscall numbers so that we don't have huge gaps in syscall table.
521  * The shuffling should be an involution: shuffle_scno(shuffle_scno(n)) == n.
522  */
523 static kernel_ulong_t
524 shuffle_scno(kernel_ulong_t scno)
525 {
526 #if defined(ARM) || defined(AARCH64) /* So far only 32-bit ARM needs this */
527         if (scno < ARM_FIRST_SHUFFLED_SYSCALL)
528                 return scno;
529
530         /* __ARM_NR_cmpxchg? Swap with LAST_ORDINARY+1 */
531         if (scno == ARM_FIRST_SHUFFLED_SYSCALL)
532                 return 0x000ffff0;
533         if (scno == 0x000ffff0)
534                 return ARM_FIRST_SHUFFLED_SYSCALL;
535
536 # define ARM_SECOND_SHUFFLED_SYSCALL (ARM_FIRST_SHUFFLED_SYSCALL + 1)
537         /*
538          * Is it ARM specific syscall?
539          * Swap [0x000f0000, 0x000f0000 + LAST_SPECIAL] range
540          * with [SECOND_SHUFFLED, SECOND_SHUFFLED + LAST_SPECIAL] range.
541          */
542         if (scno >= 0x000f0000 &&
543             scno <= 0x000f0000 + ARM_LAST_SPECIAL_SYSCALL) {
544                 return scno - 0x000f0000 + ARM_SECOND_SHUFFLED_SYSCALL;
545         }
546         if (scno <= ARM_SECOND_SHUFFLED_SYSCALL + ARM_LAST_SPECIAL_SYSCALL) {
547                 return scno + 0x000f0000 - ARM_SECOND_SHUFFLED_SYSCALL;
548         }
549 #endif /* ARM || AARCH64 */
550
551         return scno;
552 }
553
554 const char *
555 err_name(unsigned long err)
556 {
557         if ((err < nerrnos) && errnoent[err])
558                 return errnoent[err];
559
560         return NULL;
561 }
562
563 static long get_regs_error;
564
565 void
566 clear_regs(void)
567 {
568         get_regs_error = -1;
569 }
570
571 static void get_regs(pid_t pid);
572 static int get_syscall_args(struct tcb *);
573 static int get_syscall_result(struct tcb *);
574 static int arch_get_scno(struct tcb *tcp);
575 static int arch_set_scno(struct tcb *, kernel_ulong_t);
576 static void get_error(struct tcb *, const bool);
577 static int arch_set_error(struct tcb *);
578 static int arch_set_success(struct tcb *);
579
580 struct inject_opts *inject_vec[SUPPORTED_PERSONALITIES];
581
582 static struct inject_opts *
583 tcb_inject_opts(struct tcb *tcp)
584 {
585         return (scno_in_range(tcp->scno) && tcp->inject_vec[current_personality])
586                ? &tcp->inject_vec[current_personality][tcp->scno] : NULL;
587 }
588
589
590 static long
591 tamper_with_syscall_entering(struct tcb *tcp, unsigned int *signo)
592 {
593         if (!tcp->inject_vec[current_personality]) {
594                 tcp->inject_vec[current_personality] =
595                         xcalloc(nsyscalls, sizeof(**inject_vec));
596                 memcpy(tcp->inject_vec[current_personality],
597                        inject_vec[current_personality],
598                        nsyscalls * sizeof(**inject_vec));
599         }
600
601         struct inject_opts *opts = tcb_inject_opts(tcp);
602
603         if (!opts || opts->first == 0)
604                 return 0;
605
606         --opts->first;
607
608         if (opts->first != 0)
609                 return 0;
610
611         opts->first = opts->step;
612
613         if (opts->signo > 0)
614                 *signo = opts->signo;
615         if (opts->rval != INJECT_OPTS_RVAL_DEFAULT && !arch_set_scno(tcp, -1))
616                 tcp->flags |= TCB_TAMPERED;
617
618         return 0;
619 }
620
621 static long
622 tamper_with_syscall_exiting(struct tcb *tcp)
623 {
624         struct inject_opts *opts = tcb_inject_opts(tcp);
625
626         if (!opts)
627                 return 0;
628
629         if (opts->rval >= 0) {
630                 kernel_long_t u_rval = tcp->u_rval;
631
632                 tcp->u_rval = opts->rval;
633                 if (arch_set_success(tcp)) {
634                         tcp->u_rval = u_rval;
635                 } else {
636                         tcp->u_error = 0;
637                 }
638         } else {
639                 unsigned long new_error = -opts->rval;
640
641                 if (new_error != tcp->u_error && new_error <= MAX_ERRNO_VALUE) {
642                         unsigned long u_error = tcp->u_error;
643
644                         tcp->u_error = new_error;
645                         if (arch_set_error(tcp)) {
646                                 tcp->u_error = u_error;
647                         }
648                 }
649         }
650
651         return 0;
652 }
653
654 /*
655  * Returns:
656  * 0: "ignore this ptrace stop", bail out silently.
657  * 1: ok, decoded; call
658  *    syscall_entering_finish(tcp, syscall_entering_trace(tcp, ...)).
659  * other: error; call syscall_entering_finish(tcp, res), where res is the value
660  *    returned.
661  */
662 int
663 syscall_entering_decode(struct tcb *tcp)
664 {
665         int res = get_scno(tcp);
666         if (res == 0)
667                 return res;
668         int scno_good = res;
669         if (res != 1 || (res = get_syscall_args(tcp)) != 1) {
670                 printleader(tcp);
671                 tprintf("%s(", scno_good == 1 ? tcp->s_ent->sys_name : "????");
672                 /*
673                  * " <unavailable>" will be added later by the code which
674                  * detects ptrace errors.
675                  */
676                 return res;
677         }
678
679 #ifdef LINUX_MIPSO32
680         if (SEN_syscall == tcp->s_ent->sen)
681                 decode_mips_subcall(tcp);
682 #endif
683
684 #if defined(SYS_socket_subcall) || defined(SYS_ipc_subcall)
685         switch (tcp->s_ent->sen) {
686 # ifdef SYS_socket_subcall
687                 case SEN_socketcall:
688                         decode_socket_subcall(tcp);
689                         break;
690 # endif
691 # ifdef SYS_ipc_subcall
692                 case SEN_ipc:
693                         decode_ipc_subcall(tcp);
694                         break;
695 # endif
696         }
697 #endif
698
699         return 1;
700 }
701
702 int
703 syscall_entering_trace(struct tcb *tcp, unsigned int *sig)
704 {
705         /* Restrain from fault injection while the trace executes strace code. */
706         if (hide_log(tcp)) {
707                 tcp->qual_flg &= ~QUAL_INJECT;
708         }
709
710         switch (tcp->s_ent->sen) {
711                 case SEN_execve:
712                 case SEN_execveat:
713 #if defined SPARC || defined SPARC64
714                 case SEN_execv:
715 #endif
716                         tcp->flags &= ~TCB_HIDE_LOG;
717                         break;
718         }
719
720         if (!(tcp->qual_flg & QUAL_TRACE)
721          || (tracing_paths && !pathtrace_match(tcp))
722         ) {
723                 tcp->flags |= TCB_FILTERED;
724                 return 0;
725         }
726
727         tcp->flags &= ~TCB_FILTERED;
728
729         if (hide_log(tcp)) {
730                 return 0;
731         }
732
733         if (tcp->qual_flg & QUAL_INJECT)
734                 tamper_with_syscall_entering(tcp, sig);
735
736         if (cflag == CFLAG_ONLY_STATS) {
737                 return 0;
738         }
739
740 #ifdef USE_LIBUNWIND
741         if (stack_trace_enabled) {
742                 if (tcp->s_ent->sys_flags & STACKTRACE_CAPTURE_ON_ENTER)
743                         unwind_capture_stacktrace(tcp);
744         }
745 #endif
746
747         printleader(tcp);
748         tprintf("%s(", tcp->s_ent->sys_name);
749         int res = (tcp->qual_flg & QUAL_RAW)
750                 ? printargs(tcp) : tcp->s_ent->sys_func(tcp);
751         fflush(tcp->outf);
752         return res;
753 }
754
755 void
756 syscall_entering_finish(struct tcb *tcp, int res)
757 {
758         tcp->flags |= TCB_INSYSCALL;
759         tcp->sys_func_rval = res;
760         /* Measure the entrance time as late as possible to avoid errors. */
761         if ((Tflag || cflag) && !filtered(tcp))
762                 gettimeofday(&tcp->etime, NULL);
763 }
764
765 static bool
766 syscall_tampered(struct tcb *tcp)
767 {
768         return tcp->flags & TCB_TAMPERED;
769 }
770
771 /* Returns:
772  * 0: "bail out".
773  * 1: ok.
774  * -1: error in one of ptrace ops.
775  *
776  * If not 0, call syscall_exiting_trace(tcp, res), where res is the return
777  *    value. Anyway, call syscall_exiting_finish(tcp) then.
778  */
779 int
780 syscall_exiting_decode(struct tcb *tcp, struct timeval *ptv)
781 {
782         /* Measure the exit time as early as possible to avoid errors. */
783         if ((Tflag || cflag) && !(filtered(tcp) || hide_log(tcp)))
784                 gettimeofday(ptv, NULL);
785
786 #ifdef USE_LIBUNWIND
787         if (stack_trace_enabled) {
788                 if (tcp->s_ent->sys_flags & STACKTRACE_INVALIDATE_CACHE)
789                         unwind_cache_invalidate(tcp);
790         }
791 #endif
792
793         if (filtered(tcp) || hide_log(tcp))
794                 return 0;
795
796         get_regs(tcp->pid);
797 #if SUPPORTED_PERSONALITIES > 1
798         update_personality(tcp, tcp->currpers);
799 #endif
800         return get_regs_error ? -1 : get_syscall_result(tcp);
801 }
802
803 int
804 syscall_exiting_trace(struct tcb *tcp, struct timeval tv, int res)
805 {
806         if (syserror(tcp) && syscall_tampered(tcp))
807                 tamper_with_syscall_exiting(tcp);
808
809         if (cflag) {
810                 count_syscall(tcp, &tv);
811                 if (cflag == CFLAG_ONLY_STATS) {
812                         return 0;
813                 }
814         }
815
816         /* If not in -ff mode, and printing_tcp != tcp,
817          * then the log currently does not end with output
818          * of _our syscall entry_, but with something else.
819          * We need to say which syscall's return is this.
820          *
821          * Forced reprinting via TCB_REPRINT is used only by
822          * "strace -ff -oLOG test/threaded_execve" corner case.
823          * It's the only case when -ff mode needs reprinting.
824          */
825         if ((followfork < 2 && printing_tcp != tcp) || (tcp->flags & TCB_REPRINT)) {
826                 tcp->flags &= ~TCB_REPRINT;
827                 printleader(tcp);
828                 tprintf("<... %s resumed> ", tcp->s_ent->sys_name);
829         }
830         printing_tcp = tcp;
831
832         tcp->s_prev_ent = NULL;
833         if (res != 1) {
834                 /* There was error in one of prior ptrace ops */
835                 tprints(") ");
836                 tabto();
837                 tprints("= ? <unavailable>\n");
838                 line_ended();
839                 return res;
840         }
841         tcp->s_prev_ent = tcp->s_ent;
842
843         int sys_res = 0;
844         if (tcp->qual_flg & QUAL_RAW) {
845                 /* sys_res = printargs(tcp); - but it's nop on sysexit */
846         } else {
847         /* FIXME: not_failing_only (IOW, option -z) is broken:
848          * failure of syscall is known only after syscall return.
849          * Thus we end up with something like this on, say, ENOENT:
850          *     open("does_not_exist", O_RDONLY <unfinished ...>
851          *     {next syscall decode}
852          * whereas the intended result is that open(...) line
853          * is not shown at all.
854          */
855                 if (not_failing_only && tcp->u_error)
856                         return 0;       /* ignore failed syscalls */
857                 if (tcp->sys_func_rval & RVAL_DECODED)
858                         sys_res = tcp->sys_func_rval;
859                 else
860                         sys_res = tcp->s_ent->sys_func(tcp);
861         }
862
863         tprints(") ");
864         tabto();
865         unsigned long u_error = tcp->u_error;
866
867         if (tcp->qual_flg & QUAL_RAW) {
868                 if (u_error) {
869                         tprintf("= -1 (errno %lu)", u_error);
870                 } else {
871                         tprintf("= %#" PRI_klx, tcp->u_rval);
872                 }
873                 if (syscall_tampered(tcp))
874                         tprints(" (INJECTED)");
875         } else if (!(sys_res & RVAL_NONE) && u_error) {
876                 const char *u_error_str;
877
878                 switch (u_error) {
879                 /* Blocked signals do not interrupt any syscalls.
880                  * In this case syscalls don't return ERESTARTfoo codes.
881                  *
882                  * Deadly signals set to SIG_DFL interrupt syscalls
883                  * and kill the process regardless of which of the codes below
884                  * is returned by the interrupted syscall.
885                  * In some cases, kernel forces a kernel-generated deadly
886                  * signal to be unblocked and set to SIG_DFL (and thus cause
887                  * death) if it is blocked or SIG_IGNed: for example, SIGSEGV
888                  * or SIGILL. (The alternative is to leave process spinning
889                  * forever on the faulty instruction - not useful).
890                  *
891                  * SIG_IGNed signals and non-deadly signals set to SIG_DFL
892                  * (for example, SIGCHLD, SIGWINCH) interrupt syscalls,
893                  * but kernel will always restart them.
894                  */
895                 case ERESTARTSYS:
896                         /* Most common type of signal-interrupted syscall exit code.
897                          * The system call will be restarted with the same arguments
898                          * if SA_RESTART is set; otherwise, it will fail with EINTR.
899                          */
900                         tprints("= ? ERESTARTSYS (To be restarted if SA_RESTART is set)");
901                         break;
902                 case ERESTARTNOINTR:
903                         /* Rare. For example, fork() returns this if interrupted.
904                          * SA_RESTART is ignored (assumed set): the restart is unconditional.
905                          */
906                         tprints("= ? ERESTARTNOINTR (To be restarted)");
907                         break;
908                 case ERESTARTNOHAND:
909                         /* pause(), rt_sigsuspend() etc use this code.
910                          * SA_RESTART is ignored (assumed not set):
911                          * syscall won't restart (will return EINTR instead)
912                          * even after signal with SA_RESTART set. However,
913                          * after SIG_IGN or SIG_DFL signal it will restart
914                          * (thus the name "restart only if has no handler").
915                          */
916                         tprints("= ? ERESTARTNOHAND (To be restarted if no handler)");
917                         break;
918                 case ERESTART_RESTARTBLOCK:
919                         /* Syscalls like nanosleep(), poll() which can't be
920                          * restarted with their original arguments use this
921                          * code. Kernel will execute restart_syscall() instead,
922                          * which changes arguments before restarting syscall.
923                          * SA_RESTART is ignored (assumed not set) similarly
924                          * to ERESTARTNOHAND. (Kernel can't honor SA_RESTART
925                          * since restart data is saved in "restart block"
926                          * in task struct, and if signal handler uses a syscall
927                          * which in turn saves another such restart block,
928                          * old data is lost and restart becomes impossible)
929                          */
930                         tprints("= ? ERESTART_RESTARTBLOCK (Interrupted by signal)");
931                         break;
932                 default:
933                         u_error_str = err_name(u_error);
934                         if (u_error_str)
935                                 tprintf("= -1 %s (%s)",
936                                         u_error_str, strerror(u_error));
937                         else
938                                 tprintf("= -1 %lu (%s)",
939                                         u_error, strerror(u_error));
940                         break;
941                 }
942                 if (syscall_tampered(tcp))
943                         tprints(" (INJECTED)");
944                 if ((sys_res & RVAL_STR) && tcp->auxstr)
945                         tprintf(" (%s)", tcp->auxstr);
946         } else {
947                 if (sys_res & RVAL_NONE)
948                         tprints("= ?");
949                 else {
950                         switch (sys_res & RVAL_MASK) {
951                         case RVAL_HEX:
952 #if ANY_WORDSIZE_LESS_THAN_KERNEL_LONG
953                                 if (current_wordsize < sizeof(tcp->u_rval)) {
954                                         tprintf("= %#x",
955                                                 (unsigned int) tcp->u_rval);
956                                 } else
957 #endif
958                                 {
959                                         tprintf("= %#" PRI_klx, tcp->u_rval);
960                                 }
961                                 break;
962                         case RVAL_OCTAL:
963                                 tprints("= ");
964                                 print_numeric_long_umask(tcp->u_rval);
965                                 break;
966                         case RVAL_UDECIMAL:
967 #if ANY_WORDSIZE_LESS_THAN_KERNEL_LONG
968                                 if (current_wordsize < sizeof(tcp->u_rval)) {
969                                         tprintf("= %u",
970                                                 (unsigned int) tcp->u_rval);
971                                 } else
972 #endif
973                                 {
974                                         tprintf("= %" PRI_klu, tcp->u_rval);
975                                 }
976                                 break;
977                         case RVAL_DECIMAL:
978                                 tprintf("= %" PRI_kld, tcp->u_rval);
979                                 break;
980                         case RVAL_FD:
981                                 if (show_fd_path) {
982                                         tprints("= ");
983                                         printfd(tcp, tcp->u_rval);
984                                 } else
985                                         tprintf("= %" PRI_kld, tcp->u_rval);
986                                 break;
987                         default:
988                                 error_msg("invalid rval format");
989                                 break;
990                         }
991                 }
992                 if ((sys_res & RVAL_STR) && tcp->auxstr)
993                         tprintf(" (%s)", tcp->auxstr);
994                 if (syscall_tampered(tcp))
995                         tprints(" (INJECTED)");
996         }
997         if (Tflag) {
998                 tv_sub(&tv, &tv, &tcp->etime);
999                 tprintf(" <%ld.%06ld>",
1000                         (long) tv.tv_sec, (long) tv.tv_usec);
1001         }
1002         tprints("\n");
1003         dumpio(tcp);
1004         line_ended();
1005
1006 #ifdef USE_LIBUNWIND
1007         if (stack_trace_enabled)
1008                 unwind_print_stacktrace(tcp);
1009 #endif
1010         return 0;
1011 }
1012
1013 void
1014 syscall_exiting_finish(struct tcb *tcp)
1015 {
1016         tcp->flags &= ~(TCB_INSYSCALL | TCB_TAMPERED);
1017         tcp->sys_func_rval = 0;
1018         free_tcb_priv_data(tcp);
1019 }
1020
1021 bool
1022 is_erestart(struct tcb *tcp)
1023 {
1024         switch (tcp->u_error) {
1025                 case ERESTARTSYS:
1026                 case ERESTARTNOINTR:
1027                 case ERESTARTNOHAND:
1028                 case ERESTART_RESTARTBLOCK:
1029                         return true;
1030                 default:
1031                         return false;
1032         }
1033 }
1034
1035 static unsigned long saved_u_error;
1036
1037 void
1038 temporarily_clear_syserror(struct tcb *tcp)
1039 {
1040         saved_u_error = tcp->u_error;
1041         tcp->u_error = 0;
1042 }
1043
1044 void
1045 restore_cleared_syserror(struct tcb *tcp)
1046 {
1047         tcp->u_error = saved_u_error;
1048 }
1049
1050 #include "arch_regs.c"
1051
1052 #ifdef HAVE_GETRVAL2
1053 # include "arch_getrval2.c"
1054 #endif
1055
1056 void
1057 print_pc(struct tcb *tcp)
1058 {
1059 #if defined ARCH_PC_REG
1060 # define ARCH_GET_PC 0
1061 #elif defined ARCH_PC_PEEK_ADDR
1062         kernel_ulong_t pc;
1063 # define ARCH_PC_REG pc
1064 # define ARCH_GET_PC upeek(tcp->pid, ARCH_PC_PEEK_ADDR, &pc)
1065 #else
1066 # error Neither ARCH_PC_REG nor ARCH_PC_PEEK_ADDR is defined
1067 #endif
1068         get_regs(tcp->pid);
1069         if (get_regs_error || ARCH_GET_PC)
1070                 tprints(current_wordsize == 4 ? "[????????] "
1071                                               : "[????????????????] ");
1072         else
1073                 tprintf(current_wordsize == 4
1074                         ? "[%08" PRI_klx "] " : "[%016" PRI_klx "] ",
1075                         (kernel_ulong_t) ARCH_PC_REG);
1076 }
1077
1078 #include "getregs_old.h"
1079
1080 #undef ptrace_getregset_or_getregs
1081 #undef ptrace_setregset_or_setregs
1082 #ifdef ARCH_REGS_FOR_GETREGSET
1083
1084 # define ptrace_getregset_or_getregs ptrace_getregset
1085 static long
1086 ptrace_getregset(pid_t pid)
1087 {
1088 # ifdef ARCH_IOVEC_FOR_GETREGSET
1089         /* variable iovec */
1090         ARCH_IOVEC_FOR_GETREGSET.iov_len = sizeof(ARCH_REGS_FOR_GETREGSET);
1091         return ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS,
1092                       &ARCH_IOVEC_FOR_GETREGSET);
1093 # else
1094         /* constant iovec */
1095         static struct iovec io = {
1096                 .iov_base = &ARCH_REGS_FOR_GETREGSET,
1097                 .iov_len = sizeof(ARCH_REGS_FOR_GETREGSET)
1098         };
1099         return ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &io);
1100
1101 # endif
1102 }
1103
1104 # ifndef HAVE_GETREGS_OLD
1105 #  define ptrace_setregset_or_setregs ptrace_setregset
1106 static int
1107 ptrace_setregset(pid_t pid)
1108 {
1109 #  ifdef ARCH_IOVEC_FOR_GETREGSET
1110         /* variable iovec */
1111         return ptrace(PTRACE_SETREGSET, pid, NT_PRSTATUS,
1112                       &ARCH_IOVEC_FOR_GETREGSET);
1113 #  else
1114         /* constant iovec */
1115         static struct iovec io = {
1116                 .iov_base = &ARCH_REGS_FOR_GETREGSET,
1117                 .iov_len = sizeof(ARCH_REGS_FOR_GETREGSET)
1118         };
1119         return ptrace(PTRACE_SETREGSET, pid, NT_PRSTATUS, &io);
1120 #  endif
1121 }
1122 # endif /* !HAVE_GETREGS_OLD */
1123
1124 #elif defined ARCH_REGS_FOR_GETREGS
1125
1126 # define ptrace_getregset_or_getregs ptrace_getregs
1127 static long
1128 ptrace_getregs(pid_t pid)
1129 {
1130 # if defined SPARC || defined SPARC64
1131         /* SPARC systems have the meaning of data and addr reversed */
1132         return ptrace(PTRACE_GETREGS, pid, (void *) &ARCH_REGS_FOR_GETREGS, 0);
1133 # else
1134         return ptrace(PTRACE_GETREGS, pid, NULL, &ARCH_REGS_FOR_GETREGS);
1135 # endif
1136 }
1137
1138 # ifndef HAVE_GETREGS_OLD
1139 #  define ptrace_setregset_or_setregs ptrace_setregs
1140 static int
1141 ptrace_setregs(pid_t pid)
1142 {
1143 #  if defined SPARC || defined SPARC64
1144         /* SPARC systems have the meaning of data and addr reversed */
1145         return ptrace(PTRACE_SETREGS, pid, (void *) &ARCH_REGS_FOR_GETREGS, 0);
1146 #  else
1147         return ptrace(PTRACE_SETREGS, pid, NULL, &ARCH_REGS_FOR_GETREGS);
1148 #  endif
1149 }
1150 # endif /* !HAVE_GETREGS_OLD */
1151
1152 #endif /* ARCH_REGS_FOR_GETREGSET || ARCH_REGS_FOR_GETREGS */
1153
1154 static void
1155 get_regs(pid_t pid)
1156 {
1157 #undef USE_GET_SYSCALL_RESULT_REGS
1158 #ifdef ptrace_getregset_or_getregs
1159
1160         if (get_regs_error != -1)
1161                 return;
1162
1163 # ifdef HAVE_GETREGS_OLD
1164         /*
1165          * Try PTRACE_GETREGSET/PTRACE_GETREGS first,
1166          * fallback to getregs_old.
1167          */
1168         static int use_getregs_old;
1169         if (use_getregs_old < 0) {
1170                 get_regs_error = ptrace_getregset_or_getregs(pid);
1171                 return;
1172         } else if (use_getregs_old == 0) {
1173                 get_regs_error = ptrace_getregset_or_getregs(pid);
1174                 if (get_regs_error >= 0) {
1175                         use_getregs_old = -1;
1176                         return;
1177                 }
1178                 if (errno == EPERM || errno == ESRCH)
1179                         return;
1180                 use_getregs_old = 1;
1181         }
1182         get_regs_error = getregs_old(pid);
1183 # else /* !HAVE_GETREGS_OLD */
1184         /* Assume that PTRACE_GETREGSET/PTRACE_GETREGS works. */
1185         get_regs_error = ptrace_getregset_or_getregs(pid);
1186 # endif /* !HAVE_GETREGS_OLD */
1187
1188 #else /* !ptrace_getregset_or_getregs */
1189
1190 # define USE_GET_SYSCALL_RESULT_REGS 1
1191 # warning get_regs is not implemented for this architecture yet
1192         get_regs_error = 0;
1193
1194 #endif /* !ptrace_getregset_or_getregs */
1195 }
1196
1197 #ifdef ptrace_setregset_or_setregs
1198 static int
1199 set_regs(pid_t pid)
1200 {
1201         return ptrace_setregset_or_setregs(pid);
1202 }
1203 #endif /* ptrace_setregset_or_setregs */
1204
1205 struct sysent_buf {
1206         struct tcb *tcp;
1207         struct_sysent ent;
1208         char buf[sizeof("syscall_%lu") + sizeof(kernel_ulong_t) * 3];
1209 };
1210
1211 static void
1212 free_sysent_buf(void *ptr)
1213 {
1214         struct sysent_buf *s = ptr;
1215         s->tcp->s_prev_ent = s->tcp->s_ent = NULL;
1216         free(ptr);
1217 }
1218
1219 /*
1220  * Returns:
1221  * 0: "ignore this ptrace stop", syscall_entering_decode() should return a "bail
1222  *    out silently" code.
1223  * 1: ok, continue in syscall_entering_decode().
1224  * other: error, syscall_entering_decode() should print error indicator
1225  *    ("????" etc) and return an appropriate code.
1226  */
1227 int
1228 get_scno(struct tcb *tcp)
1229 {
1230         get_regs(tcp->pid);
1231
1232         if (get_regs_error)
1233                 return -1;
1234
1235         int rc = arch_get_scno(tcp);
1236         if (rc != 1)
1237                 return rc;
1238
1239         if (scno_is_valid(tcp->scno)) {
1240                 tcp->s_ent = &sysent[tcp->scno];
1241                 tcp->qual_flg = qual_flags(tcp->scno);
1242         } else {
1243                 struct sysent_buf *s = xcalloc(1, sizeof(*s));
1244
1245                 s->tcp = tcp;
1246                 s->ent.nargs = MAX_ARGS;
1247                 s->ent.sen = SEN_printargs;
1248                 s->ent.sys_func = printargs;
1249                 s->ent.sys_name = s->buf;
1250                 sprintf(s->buf, "syscall_%" PRI_klu, shuffle_scno(tcp->scno));
1251
1252                 tcp->s_ent = &s->ent;
1253                 tcp->qual_flg = QUAL_RAW | DEFAULT_QUAL_FLAGS;
1254
1255                 set_tcb_priv_data(tcp, s, free_sysent_buf);
1256
1257                 if (debug_flag)
1258                         error_msg("pid %d invalid syscall %" PRI_kld,
1259                                   tcp->pid, tcp->scno);
1260         }
1261         return 1;
1262 }
1263
1264 #ifdef USE_GET_SYSCALL_RESULT_REGS
1265 static int get_syscall_result_regs(struct tcb *);
1266 #endif
1267
1268 /* Returns:
1269  * 1: ok, continue in syscall_exiting_trace().
1270  * -1: error, syscall_exiting_trace() should print error indicator
1271  *    ("????" etc) and bail out.
1272  */
1273 static int
1274 get_syscall_result(struct tcb *tcp)
1275 {
1276 #ifdef USE_GET_SYSCALL_RESULT_REGS
1277         if (get_syscall_result_regs(tcp))
1278                 return -1;
1279 #endif
1280         tcp->u_error = 0;
1281         get_error(tcp, !(tcp->s_ent->sys_flags & SYSCALL_NEVER_FAILS));
1282
1283         return 1;
1284 }
1285
1286 #include "get_scno.c"
1287 #include "set_scno.c"
1288 #include "get_syscall_args.c"
1289 #ifdef USE_GET_SYSCALL_RESULT_REGS
1290 # include "get_syscall_result.c"
1291 #endif
1292 #include "get_error.c"
1293 #include "set_error.c"
1294 #ifdef HAVE_GETREGS_OLD
1295 # include "getregs_old.c"
1296 #endif
1297
1298 const char *
1299 syscall_name(kernel_ulong_t scno)
1300 {
1301 #if defined X32_PERSONALITY_NUMBER && defined __X32_SYSCALL_BIT
1302         if (current_personality == X32_PERSONALITY_NUMBER)
1303                 scno &= ~__X32_SYSCALL_BIT;
1304 #endif
1305         return scno_is_valid(scno) ? sysent[scno].sys_name : NULL;
1306 }