Commit | Line | Data |
---|---|---|
5f572dec | 1 | /* Linux-specific ptrace manipulation routines. |
32d0add0 | 2 | Copyright (C) 2012-2015 Free Software Foundation, Inc. |
5f572dec JK |
3 | |
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 3 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
18 | ||
727605ca | 19 | #include "common-defs.h" |
5f572dec | 20 | #include "linux-ptrace.h" |
87b0bb13 | 21 | #include "linux-procfs.h" |
125f8a3d | 22 | #include "linux-waitpid.h" |
87b0bb13 | 23 | #include "buffer.h" |
8bdce1ff | 24 | #include "gdb_wait.h" |
87b0bb13 | 25 | |
59ee9f94 WN |
26 | #include <stdint.h> |
27 | ||
96d7229d LM |
28 | /* Stores the currently supported ptrace options. A value of |
29 | -1 means we did not check for features yet. A value of 0 means | |
30 | there are no supported features. */ | |
31 | static int current_ptrace_options = -1; | |
32 | ||
8009206a TT |
33 | /* Additional flags to test. */ |
34 | ||
35 | static int additional_flags; | |
36 | ||
7ae1a6a6 PA |
37 | /* Find all possible reasons we could fail to attach PID and append |
38 | these as strings to the already initialized BUFFER. '\0' | |
39 | termination of BUFFER must be done by the caller. */ | |
87b0bb13 JK |
40 | |
41 | void | |
7ae1a6a6 | 42 | linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer) |
87b0bb13 JK |
43 | { |
44 | pid_t tracerpid; | |
45 | ||
8784d563 | 46 | tracerpid = linux_proc_get_tracerpid_nowarn (pid); |
87b0bb13 | 47 | if (tracerpid > 0) |
7ae1a6a6 PA |
48 | buffer_xml_printf (buffer, _("process %d is already traced " |
49 | "by process %d"), | |
87b0bb13 JK |
50 | (int) pid, (int) tracerpid); |
51 | ||
8784d563 | 52 | if (linux_proc_pid_is_zombie_nowarn (pid)) |
7ae1a6a6 PA |
53 | buffer_xml_printf (buffer, _("process %d is a zombie " |
54 | "- the process has already terminated"), | |
87b0bb13 JK |
55 | (int) pid); |
56 | } | |
aa7c7447 | 57 | |
8784d563 PA |
58 | /* See linux-ptrace.h. */ |
59 | ||
60 | char * | |
61 | linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err) | |
62 | { | |
63 | static char *reason_string; | |
64 | struct buffer buffer; | |
65 | char *warnings; | |
66 | long lwpid = ptid_get_lwp (ptid); | |
67 | ||
68 | xfree (reason_string); | |
69 | ||
70 | buffer_init (&buffer); | |
71 | linux_ptrace_attach_fail_reason (lwpid, &buffer); | |
72 | buffer_grow_str0 (&buffer, ""); | |
73 | warnings = buffer_finish (&buffer); | |
74 | if (warnings[0] != '\0') | |
75 | reason_string = xstrprintf ("%s (%d), %s", | |
049bb5de | 76 | safe_strerror (err), err, warnings); |
8784d563 PA |
77 | else |
78 | reason_string = xstrprintf ("%s (%d)", | |
049bb5de | 79 | safe_strerror (err), err); |
8784d563 PA |
80 | xfree (warnings); |
81 | return reason_string; | |
82 | } | |
83 | ||
6e3c039e | 84 | #if defined __i386__ || defined __x86_64__ |
aa7c7447 JK |
85 | |
86 | /* Address of the 'ret' instruction in asm code block below. */ | |
56000a98 | 87 | EXTERN_C void linux_ptrace_test_ret_to_nx_instr (void); |
aa7c7447 JK |
88 | |
89 | #include <sys/reg.h> | |
90 | #include <sys/mman.h> | |
91 | #include <signal.h> | |
aa7c7447 | 92 | |
6e3c039e | 93 | #endif /* defined __i386__ || defined __x86_64__ */ |
aa7c7447 JK |
94 | |
95 | /* Test broken off-trunk Linux kernel patchset for NX support on i386. It was | |
6e3c039e JK |
96 | removed in Fedora kernel 88fa1f0332d188795ed73d7ac2b1564e11a0b4cd. |
97 | ||
98 | Test also x86_64 arch for PaX support. */ | |
aa7c7447 JK |
99 | |
100 | static void | |
101 | linux_ptrace_test_ret_to_nx (void) | |
102 | { | |
6e3c039e | 103 | #if defined __i386__ || defined __x86_64__ |
aa7c7447 JK |
104 | pid_t child, got_pid; |
105 | gdb_byte *return_address, *pc; | |
106 | long l; | |
61a31a67 | 107 | int status, kill_status; |
aa7c7447 JK |
108 | |
109 | return_address = mmap (NULL, 2, PROT_READ | PROT_WRITE, | |
110 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
111 | if (return_address == MAP_FAILED) | |
112 | { | |
113 | warning (_("linux_ptrace_test_ret_to_nx: Cannot mmap: %s"), | |
049bb5de | 114 | safe_strerror (errno)); |
aa7c7447 JK |
115 | return; |
116 | } | |
117 | ||
118 | /* Put there 'int3'. */ | |
119 | *return_address = 0xcc; | |
120 | ||
121 | child = fork (); | |
122 | switch (child) | |
123 | { | |
124 | case -1: | |
125 | warning (_("linux_ptrace_test_ret_to_nx: Cannot fork: %s"), | |
049bb5de | 126 | safe_strerror (errno)); |
aa7c7447 JK |
127 | return; |
128 | ||
129 | case 0: | |
96d7229d LM |
130 | l = ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) NULL, |
131 | (PTRACE_TYPE_ARG4) NULL); | |
aa7c7447 JK |
132 | if (l != 0) |
133 | warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_TRACEME: %s"), | |
049bb5de | 134 | safe_strerror (errno)); |
aa7c7447 JK |
135 | else |
136 | { | |
6e3c039e | 137 | #if defined __i386__ |
aa7c7447 JK |
138 | asm volatile ("pushl %0;" |
139 | ".globl linux_ptrace_test_ret_to_nx_instr;" | |
140 | "linux_ptrace_test_ret_to_nx_instr:" | |
141 | "ret" | |
142 | : : "r" (return_address) : "%esp", "memory"); | |
6e3c039e JK |
143 | #elif defined __x86_64__ |
144 | asm volatile ("pushq %0;" | |
145 | ".globl linux_ptrace_test_ret_to_nx_instr;" | |
146 | "linux_ptrace_test_ret_to_nx_instr:" | |
147 | "ret" | |
bdad4180 MF |
148 | : : "r" ((uint64_t) (uintptr_t) return_address) |
149 | : "%rsp", "memory"); | |
6e3c039e JK |
150 | #else |
151 | # error "!__i386__ && !__x86_64__" | |
152 | #endif | |
aa7c7447 JK |
153 | gdb_assert_not_reached ("asm block did not terminate"); |
154 | } | |
155 | ||
156 | _exit (1); | |
157 | } | |
158 | ||
6e3c039e | 159 | errno = 0; |
aa7c7447 | 160 | got_pid = waitpid (child, &status, 0); |
6e3c039e JK |
161 | if (got_pid != child) |
162 | { | |
163 | warning (_("linux_ptrace_test_ret_to_nx: waitpid returned %ld: %s"), | |
049bb5de | 164 | (long) got_pid, safe_strerror (errno)); |
6e3c039e JK |
165 | return; |
166 | } | |
167 | ||
168 | if (WIFSIGNALED (status)) | |
169 | { | |
170 | if (WTERMSIG (status) != SIGKILL) | |
171 | warning (_("linux_ptrace_test_ret_to_nx: WTERMSIG %d is not SIGKILL!"), | |
172 | (int) WTERMSIG (status)); | |
173 | else | |
174 | warning (_("Cannot call inferior functions, Linux kernel PaX " | |
175 | "protection forbids return to non-executable pages!")); | |
176 | return; | |
177 | } | |
178 | ||
179 | if (!WIFSTOPPED (status)) | |
180 | { | |
181 | warning (_("linux_ptrace_test_ret_to_nx: status %d is not WIFSTOPPED!"), | |
182 | status); | |
183 | return; | |
184 | } | |
aa7c7447 JK |
185 | |
186 | /* We may get SIGSEGV due to missing PROT_EXEC of the return_address. */ | |
6e3c039e JK |
187 | if (WSTOPSIG (status) != SIGTRAP && WSTOPSIG (status) != SIGSEGV) |
188 | { | |
189 | warning (_("linux_ptrace_test_ret_to_nx: " | |
190 | "WSTOPSIG %d is neither SIGTRAP nor SIGSEGV!"), | |
191 | (int) WSTOPSIG (status)); | |
192 | return; | |
193 | } | |
aa7c7447 JK |
194 | |
195 | errno = 0; | |
6e3c039e | 196 | #if defined __i386__ |
96d7229d LM |
197 | l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (EIP * 4), |
198 | (PTRACE_TYPE_ARG4) NULL); | |
6e3c039e | 199 | #elif defined __x86_64__ |
96d7229d LM |
200 | l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (RIP * 8), |
201 | (PTRACE_TYPE_ARG4) NULL); | |
6e3c039e JK |
202 | #else |
203 | # error "!__i386__ && !__x86_64__" | |
204 | #endif | |
205 | if (errno != 0) | |
206 | { | |
207 | warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_PEEKUSER: %s"), | |
049bb5de | 208 | safe_strerror (errno)); |
6e3c039e JK |
209 | return; |
210 | } | |
aa7c7447 JK |
211 | pc = (void *) (uintptr_t) l; |
212 | ||
61a31a67 | 213 | kill (child, SIGKILL); |
96d7229d LM |
214 | ptrace (PTRACE_KILL, child, (PTRACE_TYPE_ARG3) NULL, |
215 | (PTRACE_TYPE_ARG4) NULL); | |
61a31a67 JK |
216 | |
217 | errno = 0; | |
218 | got_pid = waitpid (child, &kill_status, 0); | |
219 | if (got_pid != child) | |
6e3c039e | 220 | { |
61a31a67 JK |
221 | warning (_("linux_ptrace_test_ret_to_nx: " |
222 | "PTRACE_KILL waitpid returned %ld: %s"), | |
049bb5de | 223 | (long) got_pid, safe_strerror (errno)); |
6e3c039e JK |
224 | return; |
225 | } | |
61a31a67 | 226 | if (!WIFSIGNALED (kill_status)) |
aa7c7447 | 227 | { |
61a31a67 JK |
228 | warning (_("linux_ptrace_test_ret_to_nx: " |
229 | "PTRACE_KILL status %d is not WIFSIGNALED!"), | |
230 | status); | |
231 | return; | |
aa7c7447 JK |
232 | } |
233 | ||
234 | /* + 1 is there as x86* stops after the 'int3' instruction. */ | |
235 | if (WSTOPSIG (status) == SIGTRAP && pc == return_address + 1) | |
236 | { | |
237 | /* PASS */ | |
238 | return; | |
239 | } | |
240 | ||
241 | /* We may get SIGSEGV due to missing PROT_EXEC of the RETURN_ADDRESS page. */ | |
242 | if (WSTOPSIG (status) == SIGSEGV && pc == return_address) | |
243 | { | |
244 | /* PASS */ | |
245 | return; | |
246 | } | |
247 | ||
6e3c039e JK |
248 | if ((void (*) (void)) pc != &linux_ptrace_test_ret_to_nx_instr) |
249 | warning (_("linux_ptrace_test_ret_to_nx: PC %p is neither near return " | |
250 | "address %p nor is the return instruction %p!"), | |
251 | pc, return_address, &linux_ptrace_test_ret_to_nx_instr); | |
252 | else | |
025e6dce PA |
253 | warning (_("Cannot call inferior functions on this system - " |
254 | "Linux kernel with broken i386 NX (non-executable pages) " | |
255 | "support detected!")); | |
6e3c039e | 256 | #endif /* defined __i386__ || defined __x86_64__ */ |
aa7c7447 JK |
257 | } |
258 | ||
96d7229d LM |
259 | /* Helper function to fork a process and make the child process call |
260 | the function FUNCTION, passing CHILD_STACK as parameter. | |
261 | ||
262 | For MMU-less targets, clone is used instead of fork, and | |
263 | CHILD_STACK is used as stack space for the cloned child. If NULL, | |
264 | stack space is allocated via malloc (and subsequently passed to | |
265 | FUNCTION). For MMU targets, CHILD_STACK is ignored. */ | |
266 | ||
267 | static int | |
268 | linux_fork_to_function (gdb_byte *child_stack, void (*function) (gdb_byte *)) | |
269 | { | |
270 | int child_pid; | |
271 | ||
272 | /* Sanity check the function pointer. */ | |
273 | gdb_assert (function != NULL); | |
274 | ||
275 | #if defined(__UCLIBC__) && defined(HAS_NOMMU) | |
276 | #define STACK_SIZE 4096 | |
277 | ||
278 | if (child_stack == NULL) | |
279 | child_stack = xmalloc (STACK_SIZE * 4); | |
280 | ||
281 | /* Use CLONE_VM instead of fork, to support uClinux (no MMU). */ | |
101158d9 | 282 | #ifdef __ia64__ |
96d7229d LM |
283 | child_pid = __clone2 (function, child_stack, STACK_SIZE, |
284 | CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2); | |
101158d9 | 285 | #else /* !__ia64__ */ |
96d7229d LM |
286 | child_pid = clone (function, child_stack + STACK_SIZE, |
287 | CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2); | |
101158d9 | 288 | #endif /* !__ia64__ */ |
96d7229d LM |
289 | #else /* !defined(__UCLIBC) && defined(HAS_NOMMU) */ |
290 | child_pid = fork (); | |
291 | ||
292 | if (child_pid == 0) | |
293 | function (NULL); | |
294 | #endif /* defined(__UCLIBC) && defined(HAS_NOMMU) */ | |
295 | ||
296 | if (child_pid == -1) | |
297 | perror_with_name (("fork")); | |
298 | ||
299 | return child_pid; | |
300 | } | |
301 | ||
302 | /* A helper function for linux_check_ptrace_features, called after | |
303 | the child forks a grandchild. */ | |
304 | ||
305 | static void | |
306 | linux_grandchild_function (gdb_byte *child_stack) | |
307 | { | |
308 | /* Free any allocated stack. */ | |
309 | xfree (child_stack); | |
310 | ||
311 | /* This code is only reacheable by the grandchild (child's child) | |
312 | process. */ | |
313 | _exit (0); | |
314 | } | |
315 | ||
316 | /* A helper function for linux_check_ptrace_features, called after | |
317 | the parent process forks a child. The child allows itself to | |
318 | be traced by its parent. */ | |
319 | ||
320 | static void | |
321 | linux_child_function (gdb_byte *child_stack) | |
322 | { | |
323 | ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0); | |
324 | kill (getpid (), SIGSTOP); | |
325 | ||
326 | /* Fork a grandchild. */ | |
327 | linux_fork_to_function (child_stack, linux_grandchild_function); | |
328 | ||
329 | /* This code is only reacheable by the child (grandchild's parent) | |
330 | process. */ | |
331 | _exit (0); | |
332 | } | |
333 | ||
8ae377e8 PA |
334 | static void linux_test_for_tracesysgood (int child_pid); |
335 | static void linux_test_for_tracefork (int child_pid); | |
beed38b8 | 336 | static void linux_test_for_exitkill (int child_pid); |
8ae377e8 | 337 | |
96d7229d LM |
338 | /* Determine ptrace features available on this target. */ |
339 | ||
340 | static void | |
341 | linux_check_ptrace_features (void) | |
342 | { | |
343 | int child_pid, ret, status; | |
96d7229d LM |
344 | |
345 | /* Initialize the options. */ | |
346 | current_ptrace_options = 0; | |
347 | ||
348 | /* Fork a child so we can do some testing. The child will call | |
349 | linux_child_function and will get traced. The child will | |
350 | eventually fork a grandchild so we can test fork event | |
351 | reporting. */ | |
352 | child_pid = linux_fork_to_function (NULL, linux_child_function); | |
353 | ||
354 | ret = my_waitpid (child_pid, &status, 0); | |
355 | if (ret == -1) | |
356 | perror_with_name (("waitpid")); | |
357 | else if (ret != child_pid) | |
358 | error (_("linux_check_ptrace_features: waitpid: unexpected result %d."), | |
359 | ret); | |
360 | if (! WIFSTOPPED (status)) | |
361 | error (_("linux_check_ptrace_features: waitpid: unexpected status %d."), | |
362 | status); | |
363 | ||
8ae377e8 | 364 | linux_test_for_tracesysgood (child_pid); |
96d7229d | 365 | |
8ae377e8 PA |
366 | linux_test_for_tracefork (child_pid); |
367 | ||
beed38b8 JB |
368 | linux_test_for_exitkill (child_pid); |
369 | ||
8ae377e8 PA |
370 | /* Clean things up and kill any pending children. */ |
371 | do | |
96d7229d LM |
372 | { |
373 | ret = ptrace (PTRACE_KILL, child_pid, (PTRACE_TYPE_ARG3) 0, | |
374 | (PTRACE_TYPE_ARG4) 0); | |
375 | if (ret != 0) | |
8ae377e8 PA |
376 | warning (_("linux_check_ptrace_features: failed to kill child")); |
377 | my_waitpid (child_pid, &status, 0); | |
96d7229d | 378 | } |
8ae377e8 PA |
379 | while (WIFSTOPPED (status)); |
380 | } | |
96d7229d | 381 | |
8ae377e8 PA |
382 | /* Determine if PTRACE_O_TRACESYSGOOD can be used to catch |
383 | syscalls. */ | |
384 | ||
385 | static void | |
386 | linux_test_for_tracesysgood (int child_pid) | |
387 | { | |
8ae377e8 PA |
388 | int ret; |
389 | ||
8009206a TT |
390 | if ((additional_flags & PTRACE_O_TRACESYSGOOD) == 0) |
391 | return; | |
392 | ||
96d7229d LM |
393 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, |
394 | (PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD); | |
8009206a | 395 | |
96d7229d LM |
396 | if (ret == 0) |
397 | current_ptrace_options |= PTRACE_O_TRACESYSGOOD; | |
8ae377e8 | 398 | } |
96d7229d | 399 | |
8ae377e8 PA |
400 | /* Determine if PTRACE_O_TRACEFORK can be used to follow fork |
401 | events. */ | |
402 | ||
403 | static void | |
404 | linux_test_for_tracefork (int child_pid) | |
405 | { | |
406 | int ret, status; | |
407 | long second_pid; | |
408 | ||
409 | /* First, set the PTRACE_O_TRACEFORK option. If this fails, we | |
410 | know for sure that it is not supported. */ | |
411 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, | |
412 | (PTRACE_TYPE_ARG4) PTRACE_O_TRACEFORK); | |
413 | ||
414 | if (ret != 0) | |
415 | return; | |
416 | ||
8009206a TT |
417 | if ((additional_flags & PTRACE_O_TRACEVFORKDONE) != 0) |
418 | { | |
419 | /* Check if the target supports PTRACE_O_TRACEVFORKDONE. */ | |
420 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, | |
421 | (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK | |
422 | | PTRACE_O_TRACEVFORKDONE)); | |
423 | if (ret == 0) | |
424 | current_ptrace_options |= PTRACE_O_TRACEVFORKDONE; | |
425 | } | |
96d7229d LM |
426 | |
427 | /* Setting PTRACE_O_TRACEFORK did not cause an error, however we | |
428 | don't know for sure that the feature is available; old | |
429 | versions of PTRACE_SETOPTIONS ignored unknown options. | |
430 | Therefore, we attach to the child process, use PTRACE_SETOPTIONS | |
431 | to enable fork tracing, and let it fork. If the process exits, | |
432 | we assume that we can't use PTRACE_O_TRACEFORK; if we get the | |
433 | fork notification, and we can extract the new child's PID, then | |
434 | we assume that we can. | |
435 | ||
436 | We do not explicitly check for vfork tracing here. It is | |
437 | assumed that vfork tracing is available whenever fork tracing | |
438 | is available. */ | |
439 | ret = ptrace (PTRACE_CONT, child_pid, (PTRACE_TYPE_ARG3) 0, | |
440 | (PTRACE_TYPE_ARG4) 0); | |
441 | if (ret != 0) | |
8ae377e8 | 442 | warning (_("linux_test_for_tracefork: failed to resume child")); |
96d7229d LM |
443 | |
444 | ret = my_waitpid (child_pid, &status, 0); | |
445 | ||
446 | /* Check if we received a fork event notification. */ | |
447 | if (ret == child_pid && WIFSTOPPED (status) | |
89a5711c | 448 | && linux_ptrace_get_extended_event (status) == PTRACE_EVENT_FORK) |
96d7229d LM |
449 | { |
450 | /* We did receive a fork event notification. Make sure its PID | |
451 | is reported. */ | |
452 | second_pid = 0; | |
453 | ret = ptrace (PTRACE_GETEVENTMSG, child_pid, (PTRACE_TYPE_ARG3) 0, | |
454 | (PTRACE_TYPE_ARG4) &second_pid); | |
455 | if (ret == 0 && second_pid != 0) | |
456 | { | |
457 | int second_status; | |
458 | ||
459 | /* We got the PID from the grandchild, which means fork | |
460 | tracing is supported. */ | |
96d7229d | 461 | current_ptrace_options |= PTRACE_O_TRACECLONE; |
8009206a TT |
462 | current_ptrace_options |= (additional_flags & (PTRACE_O_TRACEFORK |
463 | | PTRACE_O_TRACEVFORK | |
464 | | PTRACE_O_TRACEEXEC)); | |
96d7229d LM |
465 | |
466 | /* Do some cleanup and kill the grandchild. */ | |
467 | my_waitpid (second_pid, &second_status, 0); | |
468 | ret = ptrace (PTRACE_KILL, second_pid, (PTRACE_TYPE_ARG3) 0, | |
469 | (PTRACE_TYPE_ARG4) 0); | |
470 | if (ret != 0) | |
8ae377e8 | 471 | warning (_("linux_test_for_tracefork: " |
96d7229d LM |
472 | "failed to kill second child")); |
473 | my_waitpid (second_pid, &status, 0); | |
474 | } | |
475 | } | |
476 | else | |
8ae377e8 | 477 | warning (_("linux_test_for_tracefork: unexpected result from waitpid " |
96d7229d | 478 | "(%d, status 0x%x)"), ret, status); |
96d7229d LM |
479 | } |
480 | ||
beed38b8 JB |
481 | /* Determine if PTRACE_O_EXITKILL can be used. */ |
482 | ||
483 | static void | |
484 | linux_test_for_exitkill (int child_pid) | |
485 | { | |
486 | int ret; | |
487 | ||
488 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, | |
489 | (PTRACE_TYPE_ARG4) PTRACE_O_EXITKILL); | |
490 | ||
491 | if (ret == 0) | |
492 | current_ptrace_options |= PTRACE_O_EXITKILL; | |
493 | } | |
494 | ||
495 | /* Enable reporting of all currently supported ptrace events. | |
496 | ATTACHED should be nonzero if we have attached to the inferior. */ | |
96d7229d LM |
497 | |
498 | void | |
beed38b8 | 499 | linux_enable_event_reporting (pid_t pid, int attached) |
96d7229d | 500 | { |
beed38b8 JB |
501 | int ptrace_options; |
502 | ||
96d7229d LM |
503 | /* Check if we have initialized the ptrace features for this |
504 | target. If not, do it now. */ | |
505 | if (current_ptrace_options == -1) | |
506 | linux_check_ptrace_features (); | |
507 | ||
beed38b8 JB |
508 | ptrace_options = current_ptrace_options; |
509 | if (attached) | |
510 | { | |
511 | /* When attached to our inferior, we do not want the inferior | |
512 | to die with us if we terminate unexpectedly. */ | |
513 | ptrace_options &= ~PTRACE_O_EXITKILL; | |
514 | } | |
515 | ||
96d7229d LM |
516 | /* Set the options. */ |
517 | ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, | |
beed38b8 | 518 | (PTRACE_TYPE_ARG4) (uintptr_t) ptrace_options); |
96d7229d LM |
519 | } |
520 | ||
c077881a HZ |
521 | /* Disable reporting of all currently supported ptrace events. */ |
522 | ||
523 | void | |
524 | linux_disable_event_reporting (pid_t pid) | |
525 | { | |
526 | /* Set the options. */ | |
527 | ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, 0); | |
528 | } | |
529 | ||
96d7229d LM |
530 | /* Returns non-zero if PTRACE_OPTIONS is contained within |
531 | CURRENT_PTRACE_OPTIONS, therefore supported. Returns 0 | |
532 | otherwise. */ | |
533 | ||
534 | static int | |
535 | ptrace_supports_feature (int ptrace_options) | |
536 | { | |
8784d563 PA |
537 | if (current_ptrace_options == -1) |
538 | linux_check_ptrace_features (); | |
96d7229d LM |
539 | |
540 | return ((current_ptrace_options & ptrace_options) == ptrace_options); | |
541 | } | |
542 | ||
543 | /* Returns non-zero if PTRACE_EVENT_FORK is supported by ptrace, | |
544 | 0 otherwise. Note that if PTRACE_EVENT_FORK is supported so is | |
545 | PTRACE_EVENT_CLONE, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, | |
546 | since they were all added to the kernel at the same time. */ | |
547 | ||
548 | int | |
549 | linux_supports_tracefork (void) | |
550 | { | |
551 | return ptrace_supports_feature (PTRACE_O_TRACEFORK); | |
552 | } | |
553 | ||
554 | /* Returns non-zero if PTRACE_EVENT_CLONE is supported by ptrace, | |
555 | 0 otherwise. Note that if PTRACE_EVENT_CLONE is supported so is | |
556 | PTRACE_EVENT_FORK, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, | |
557 | since they were all added to the kernel at the same time. */ | |
558 | ||
559 | int | |
560 | linux_supports_traceclone (void) | |
561 | { | |
562 | return ptrace_supports_feature (PTRACE_O_TRACECLONE); | |
563 | } | |
564 | ||
565 | /* Returns non-zero if PTRACE_O_TRACEVFORKDONE is supported by | |
566 | ptrace, 0 otherwise. */ | |
567 | ||
568 | int | |
569 | linux_supports_tracevforkdone (void) | |
570 | { | |
571 | return ptrace_supports_feature (PTRACE_O_TRACEVFORKDONE); | |
572 | } | |
573 | ||
574 | /* Returns non-zero if PTRACE_O_TRACESYSGOOD is supported by ptrace, | |
575 | 0 otherwise. */ | |
576 | ||
577 | int | |
578 | linux_supports_tracesysgood (void) | |
579 | { | |
580 | return ptrace_supports_feature (PTRACE_O_TRACESYSGOOD); | |
581 | } | |
582 | ||
aa7c7447 JK |
583 | /* Display possible problems on this system. Display them only once per GDB |
584 | execution. */ | |
585 | ||
586 | void | |
587 | linux_ptrace_init_warnings (void) | |
588 | { | |
589 | static int warned = 0; | |
590 | ||
591 | if (warned) | |
592 | return; | |
593 | warned = 1; | |
594 | ||
595 | linux_ptrace_test_ret_to_nx (); | |
596 | } | |
8009206a TT |
597 | |
598 | /* Set additional ptrace flags to use. Some such flags may be checked | |
599 | by the implementation above. This function must be called before | |
600 | any other function in this file; otherwise the flags may not take | |
601 | effect appropriately. */ | |
602 | ||
603 | void | |
604 | linux_ptrace_set_additional_flags (int flags) | |
605 | { | |
606 | additional_flags = flags; | |
607 | } | |
89a5711c DB |
608 | |
609 | /* Extract extended ptrace event from wait status. */ | |
610 | ||
611 | int | |
612 | linux_ptrace_get_extended_event (int wstat) | |
613 | { | |
614 | return (wstat >> 16); | |
615 | } | |
616 | ||
617 | /* Determine whether wait status denotes an extended event. */ | |
618 | ||
619 | int | |
620 | linux_is_extended_waitstatus (int wstat) | |
621 | { | |
622 | return (linux_ptrace_get_extended_event (wstat) != 0); | |
623 | } | |
c9587f88 AT |
624 | |
625 | /* Return true if the event in LP may be caused by breakpoint. */ | |
626 | ||
627 | int | |
628 | linux_wstatus_maybe_breakpoint (int wstat) | |
629 | { | |
630 | return (WIFSTOPPED (wstat) | |
631 | && (WSTOPSIG (wstat) == SIGTRAP | |
632 | /* SIGILL and SIGSEGV are also treated as traps in case a | |
633 | breakpoint is inserted at the current PC. */ | |
634 | || WSTOPSIG (wstat) == SIGILL | |
635 | || WSTOPSIG (wstat) == SIGSEGV)); | |
636 | } |