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5f572dec | 1 | /* Linux-specific ptrace manipulation routines. |
ecd75fc8 | 2 | Copyright (C) 2012-2014 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 | ||
19 | #ifdef GDBSERVER | |
20 | #include "server.h" | |
21 | #else | |
22 | #include "defs.h" | |
0e9f083f | 23 | #include <string.h> |
5f572dec JK |
24 | #endif |
25 | ||
26 | #include "linux-ptrace.h" | |
87b0bb13 | 27 | #include "linux-procfs.h" |
125f8a3d | 28 | #include "linux-waitpid.h" |
87b0bb13 | 29 | #include "buffer.h" |
aa7c7447 | 30 | #include "gdb_assert.h" |
8bdce1ff | 31 | #include "gdb_wait.h" |
87b0bb13 | 32 | |
59ee9f94 WN |
33 | #include <stdint.h> |
34 | ||
96d7229d LM |
35 | /* Stores the currently supported ptrace options. A value of |
36 | -1 means we did not check for features yet. A value of 0 means | |
37 | there are no supported features. */ | |
38 | static int current_ptrace_options = -1; | |
39 | ||
7ae1a6a6 PA |
40 | /* Find all possible reasons we could fail to attach PID and append |
41 | these as strings to the already initialized BUFFER. '\0' | |
42 | termination of BUFFER must be done by the caller. */ | |
87b0bb13 JK |
43 | |
44 | void | |
7ae1a6a6 | 45 | linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer) |
87b0bb13 JK |
46 | { |
47 | pid_t tracerpid; | |
48 | ||
49 | tracerpid = linux_proc_get_tracerpid (pid); | |
50 | if (tracerpid > 0) | |
7ae1a6a6 PA |
51 | buffer_xml_printf (buffer, _("process %d is already traced " |
52 | "by process %d"), | |
87b0bb13 JK |
53 | (int) pid, (int) tracerpid); |
54 | ||
55 | if (linux_proc_pid_is_zombie (pid)) | |
7ae1a6a6 PA |
56 | buffer_xml_printf (buffer, _("process %d is a zombie " |
57 | "- the process has already terminated"), | |
87b0bb13 JK |
58 | (int) pid); |
59 | } | |
aa7c7447 | 60 | |
6e3c039e | 61 | #if defined __i386__ || defined __x86_64__ |
aa7c7447 JK |
62 | |
63 | /* Address of the 'ret' instruction in asm code block below. */ | |
64 | extern void (linux_ptrace_test_ret_to_nx_instr) (void); | |
65 | ||
66 | #include <sys/reg.h> | |
67 | #include <sys/mman.h> | |
68 | #include <signal.h> | |
aa7c7447 | 69 | |
6e3c039e | 70 | #endif /* defined __i386__ || defined __x86_64__ */ |
aa7c7447 JK |
71 | |
72 | /* Test broken off-trunk Linux kernel patchset for NX support on i386. It was | |
6e3c039e JK |
73 | removed in Fedora kernel 88fa1f0332d188795ed73d7ac2b1564e11a0b4cd. |
74 | ||
75 | Test also x86_64 arch for PaX support. */ | |
aa7c7447 JK |
76 | |
77 | static void | |
78 | linux_ptrace_test_ret_to_nx (void) | |
79 | { | |
6e3c039e | 80 | #if defined __i386__ || defined __x86_64__ |
aa7c7447 JK |
81 | pid_t child, got_pid; |
82 | gdb_byte *return_address, *pc; | |
83 | long l; | |
61a31a67 | 84 | int status, kill_status; |
aa7c7447 JK |
85 | |
86 | return_address = mmap (NULL, 2, PROT_READ | PROT_WRITE, | |
87 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
88 | if (return_address == MAP_FAILED) | |
89 | { | |
90 | warning (_("linux_ptrace_test_ret_to_nx: Cannot mmap: %s"), | |
91 | strerror (errno)); | |
92 | return; | |
93 | } | |
94 | ||
95 | /* Put there 'int3'. */ | |
96 | *return_address = 0xcc; | |
97 | ||
98 | child = fork (); | |
99 | switch (child) | |
100 | { | |
101 | case -1: | |
102 | warning (_("linux_ptrace_test_ret_to_nx: Cannot fork: %s"), | |
103 | strerror (errno)); | |
104 | return; | |
105 | ||
106 | case 0: | |
96d7229d LM |
107 | l = ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) NULL, |
108 | (PTRACE_TYPE_ARG4) NULL); | |
aa7c7447 JK |
109 | if (l != 0) |
110 | warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_TRACEME: %s"), | |
111 | strerror (errno)); | |
112 | else | |
113 | { | |
6e3c039e | 114 | #if defined __i386__ |
aa7c7447 JK |
115 | asm volatile ("pushl %0;" |
116 | ".globl linux_ptrace_test_ret_to_nx_instr;" | |
117 | "linux_ptrace_test_ret_to_nx_instr:" | |
118 | "ret" | |
119 | : : "r" (return_address) : "%esp", "memory"); | |
6e3c039e JK |
120 | #elif defined __x86_64__ |
121 | asm volatile ("pushq %0;" | |
122 | ".globl linux_ptrace_test_ret_to_nx_instr;" | |
123 | "linux_ptrace_test_ret_to_nx_instr:" | |
124 | "ret" | |
bdad4180 MF |
125 | : : "r" ((uint64_t) (uintptr_t) return_address) |
126 | : "%rsp", "memory"); | |
6e3c039e JK |
127 | #else |
128 | # error "!__i386__ && !__x86_64__" | |
129 | #endif | |
aa7c7447 JK |
130 | gdb_assert_not_reached ("asm block did not terminate"); |
131 | } | |
132 | ||
133 | _exit (1); | |
134 | } | |
135 | ||
6e3c039e | 136 | errno = 0; |
aa7c7447 | 137 | got_pid = waitpid (child, &status, 0); |
6e3c039e JK |
138 | if (got_pid != child) |
139 | { | |
140 | warning (_("linux_ptrace_test_ret_to_nx: waitpid returned %ld: %s"), | |
141 | (long) got_pid, strerror (errno)); | |
142 | return; | |
143 | } | |
144 | ||
145 | if (WIFSIGNALED (status)) | |
146 | { | |
147 | if (WTERMSIG (status) != SIGKILL) | |
148 | warning (_("linux_ptrace_test_ret_to_nx: WTERMSIG %d is not SIGKILL!"), | |
149 | (int) WTERMSIG (status)); | |
150 | else | |
151 | warning (_("Cannot call inferior functions, Linux kernel PaX " | |
152 | "protection forbids return to non-executable pages!")); | |
153 | return; | |
154 | } | |
155 | ||
156 | if (!WIFSTOPPED (status)) | |
157 | { | |
158 | warning (_("linux_ptrace_test_ret_to_nx: status %d is not WIFSTOPPED!"), | |
159 | status); | |
160 | return; | |
161 | } | |
aa7c7447 JK |
162 | |
163 | /* We may get SIGSEGV due to missing PROT_EXEC of the return_address. */ | |
6e3c039e JK |
164 | if (WSTOPSIG (status) != SIGTRAP && WSTOPSIG (status) != SIGSEGV) |
165 | { | |
166 | warning (_("linux_ptrace_test_ret_to_nx: " | |
167 | "WSTOPSIG %d is neither SIGTRAP nor SIGSEGV!"), | |
168 | (int) WSTOPSIG (status)); | |
169 | return; | |
170 | } | |
aa7c7447 JK |
171 | |
172 | errno = 0; | |
6e3c039e | 173 | #if defined __i386__ |
96d7229d LM |
174 | l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (EIP * 4), |
175 | (PTRACE_TYPE_ARG4) NULL); | |
6e3c039e | 176 | #elif defined __x86_64__ |
96d7229d LM |
177 | l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (RIP * 8), |
178 | (PTRACE_TYPE_ARG4) NULL); | |
6e3c039e JK |
179 | #else |
180 | # error "!__i386__ && !__x86_64__" | |
181 | #endif | |
182 | if (errno != 0) | |
183 | { | |
184 | warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_PEEKUSER: %s"), | |
185 | strerror (errno)); | |
186 | return; | |
187 | } | |
aa7c7447 JK |
188 | pc = (void *) (uintptr_t) l; |
189 | ||
61a31a67 | 190 | kill (child, SIGKILL); |
96d7229d LM |
191 | ptrace (PTRACE_KILL, child, (PTRACE_TYPE_ARG3) NULL, |
192 | (PTRACE_TYPE_ARG4) NULL); | |
61a31a67 JK |
193 | |
194 | errno = 0; | |
195 | got_pid = waitpid (child, &kill_status, 0); | |
196 | if (got_pid != child) | |
6e3c039e | 197 | { |
61a31a67 JK |
198 | warning (_("linux_ptrace_test_ret_to_nx: " |
199 | "PTRACE_KILL waitpid returned %ld: %s"), | |
200 | (long) got_pid, strerror (errno)); | |
6e3c039e JK |
201 | return; |
202 | } | |
61a31a67 | 203 | if (!WIFSIGNALED (kill_status)) |
aa7c7447 | 204 | { |
61a31a67 JK |
205 | warning (_("linux_ptrace_test_ret_to_nx: " |
206 | "PTRACE_KILL status %d is not WIFSIGNALED!"), | |
207 | status); | |
208 | return; | |
aa7c7447 JK |
209 | } |
210 | ||
211 | /* + 1 is there as x86* stops after the 'int3' instruction. */ | |
212 | if (WSTOPSIG (status) == SIGTRAP && pc == return_address + 1) | |
213 | { | |
214 | /* PASS */ | |
215 | return; | |
216 | } | |
217 | ||
218 | /* We may get SIGSEGV due to missing PROT_EXEC of the RETURN_ADDRESS page. */ | |
219 | if (WSTOPSIG (status) == SIGSEGV && pc == return_address) | |
220 | { | |
221 | /* PASS */ | |
222 | return; | |
223 | } | |
224 | ||
6e3c039e JK |
225 | if ((void (*) (void)) pc != &linux_ptrace_test_ret_to_nx_instr) |
226 | warning (_("linux_ptrace_test_ret_to_nx: PC %p is neither near return " | |
227 | "address %p nor is the return instruction %p!"), | |
228 | pc, return_address, &linux_ptrace_test_ret_to_nx_instr); | |
229 | else | |
025e6dce PA |
230 | warning (_("Cannot call inferior functions on this system - " |
231 | "Linux kernel with broken i386 NX (non-executable pages) " | |
232 | "support detected!")); | |
6e3c039e | 233 | #endif /* defined __i386__ || defined __x86_64__ */ |
aa7c7447 JK |
234 | } |
235 | ||
96d7229d LM |
236 | /* Helper function to fork a process and make the child process call |
237 | the function FUNCTION, passing CHILD_STACK as parameter. | |
238 | ||
239 | For MMU-less targets, clone is used instead of fork, and | |
240 | CHILD_STACK is used as stack space for the cloned child. If NULL, | |
241 | stack space is allocated via malloc (and subsequently passed to | |
242 | FUNCTION). For MMU targets, CHILD_STACK is ignored. */ | |
243 | ||
244 | static int | |
245 | linux_fork_to_function (gdb_byte *child_stack, void (*function) (gdb_byte *)) | |
246 | { | |
247 | int child_pid; | |
248 | ||
249 | /* Sanity check the function pointer. */ | |
250 | gdb_assert (function != NULL); | |
251 | ||
252 | #if defined(__UCLIBC__) && defined(HAS_NOMMU) | |
253 | #define STACK_SIZE 4096 | |
254 | ||
255 | if (child_stack == NULL) | |
256 | child_stack = xmalloc (STACK_SIZE * 4); | |
257 | ||
258 | /* Use CLONE_VM instead of fork, to support uClinux (no MMU). */ | |
101158d9 | 259 | #ifdef __ia64__ |
96d7229d LM |
260 | child_pid = __clone2 (function, child_stack, STACK_SIZE, |
261 | CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2); | |
101158d9 | 262 | #else /* !__ia64__ */ |
96d7229d LM |
263 | child_pid = clone (function, child_stack + STACK_SIZE, |
264 | CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2); | |
101158d9 | 265 | #endif /* !__ia64__ */ |
96d7229d LM |
266 | #else /* !defined(__UCLIBC) && defined(HAS_NOMMU) */ |
267 | child_pid = fork (); | |
268 | ||
269 | if (child_pid == 0) | |
270 | function (NULL); | |
271 | #endif /* defined(__UCLIBC) && defined(HAS_NOMMU) */ | |
272 | ||
273 | if (child_pid == -1) | |
274 | perror_with_name (("fork")); | |
275 | ||
276 | return child_pid; | |
277 | } | |
278 | ||
279 | /* A helper function for linux_check_ptrace_features, called after | |
280 | the child forks a grandchild. */ | |
281 | ||
282 | static void | |
283 | linux_grandchild_function (gdb_byte *child_stack) | |
284 | { | |
285 | /* Free any allocated stack. */ | |
286 | xfree (child_stack); | |
287 | ||
288 | /* This code is only reacheable by the grandchild (child's child) | |
289 | process. */ | |
290 | _exit (0); | |
291 | } | |
292 | ||
293 | /* A helper function for linux_check_ptrace_features, called after | |
294 | the parent process forks a child. The child allows itself to | |
295 | be traced by its parent. */ | |
296 | ||
297 | static void | |
298 | linux_child_function (gdb_byte *child_stack) | |
299 | { | |
300 | ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0); | |
301 | kill (getpid (), SIGSTOP); | |
302 | ||
303 | /* Fork a grandchild. */ | |
304 | linux_fork_to_function (child_stack, linux_grandchild_function); | |
305 | ||
306 | /* This code is only reacheable by the child (grandchild's parent) | |
307 | process. */ | |
308 | _exit (0); | |
309 | } | |
310 | ||
8ae377e8 PA |
311 | static void linux_test_for_tracesysgood (int child_pid); |
312 | static void linux_test_for_tracefork (int child_pid); | |
313 | ||
96d7229d LM |
314 | /* Determine ptrace features available on this target. */ |
315 | ||
316 | static void | |
317 | linux_check_ptrace_features (void) | |
318 | { | |
319 | int child_pid, ret, status; | |
96d7229d LM |
320 | |
321 | /* Initialize the options. */ | |
322 | current_ptrace_options = 0; | |
323 | ||
324 | /* Fork a child so we can do some testing. The child will call | |
325 | linux_child_function and will get traced. The child will | |
326 | eventually fork a grandchild so we can test fork event | |
327 | reporting. */ | |
328 | child_pid = linux_fork_to_function (NULL, linux_child_function); | |
329 | ||
330 | ret = my_waitpid (child_pid, &status, 0); | |
331 | if (ret == -1) | |
332 | perror_with_name (("waitpid")); | |
333 | else if (ret != child_pid) | |
334 | error (_("linux_check_ptrace_features: waitpid: unexpected result %d."), | |
335 | ret); | |
336 | if (! WIFSTOPPED (status)) | |
337 | error (_("linux_check_ptrace_features: waitpid: unexpected status %d."), | |
338 | status); | |
339 | ||
8ae377e8 | 340 | linux_test_for_tracesysgood (child_pid); |
96d7229d | 341 | |
8ae377e8 PA |
342 | linux_test_for_tracefork (child_pid); |
343 | ||
344 | /* Clean things up and kill any pending children. */ | |
345 | do | |
96d7229d LM |
346 | { |
347 | ret = ptrace (PTRACE_KILL, child_pid, (PTRACE_TYPE_ARG3) 0, | |
348 | (PTRACE_TYPE_ARG4) 0); | |
349 | if (ret != 0) | |
8ae377e8 PA |
350 | warning (_("linux_check_ptrace_features: failed to kill child")); |
351 | my_waitpid (child_pid, &status, 0); | |
96d7229d | 352 | } |
8ae377e8 PA |
353 | while (WIFSTOPPED (status)); |
354 | } | |
96d7229d | 355 | |
8ae377e8 PA |
356 | /* Determine if PTRACE_O_TRACESYSGOOD can be used to catch |
357 | syscalls. */ | |
358 | ||
359 | static void | |
360 | linux_test_for_tracesysgood (int child_pid) | |
361 | { | |
96d7229d | 362 | #ifdef GDBSERVER |
8ae377e8 | 363 | /* gdbserver does not support PTRACE_O_TRACESYSGOOD. */ |
96d7229d | 364 | #else |
8ae377e8 PA |
365 | int ret; |
366 | ||
96d7229d LM |
367 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, |
368 | (PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD); | |
369 | if (ret == 0) | |
370 | current_ptrace_options |= PTRACE_O_TRACESYSGOOD; | |
8ae377e8 PA |
371 | #endif |
372 | } | |
96d7229d | 373 | |
8ae377e8 PA |
374 | /* Determine if PTRACE_O_TRACEFORK can be used to follow fork |
375 | events. */ | |
376 | ||
377 | static void | |
378 | linux_test_for_tracefork (int child_pid) | |
379 | { | |
380 | int ret, status; | |
381 | long second_pid; | |
382 | ||
383 | /* First, set the PTRACE_O_TRACEFORK option. If this fails, we | |
384 | know for sure that it is not supported. */ | |
385 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, | |
386 | (PTRACE_TYPE_ARG4) PTRACE_O_TRACEFORK); | |
387 | ||
388 | if (ret != 0) | |
389 | return; | |
390 | ||
391 | #ifdef GDBSERVER | |
392 | /* gdbserver does not support PTRACE_O_TRACEVFORKDONE yet. */ | |
393 | #else | |
96d7229d LM |
394 | /* Check if the target supports PTRACE_O_TRACEVFORKDONE. */ |
395 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, | |
396 | (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK | |
397 | | PTRACE_O_TRACEVFORKDONE)); | |
398 | if (ret == 0) | |
399 | current_ptrace_options |= PTRACE_O_TRACEVFORKDONE; | |
400 | #endif | |
401 | ||
402 | /* Setting PTRACE_O_TRACEFORK did not cause an error, however we | |
403 | don't know for sure that the feature is available; old | |
404 | versions of PTRACE_SETOPTIONS ignored unknown options. | |
405 | Therefore, we attach to the child process, use PTRACE_SETOPTIONS | |
406 | to enable fork tracing, and let it fork. If the process exits, | |
407 | we assume that we can't use PTRACE_O_TRACEFORK; if we get the | |
408 | fork notification, and we can extract the new child's PID, then | |
409 | we assume that we can. | |
410 | ||
411 | We do not explicitly check for vfork tracing here. It is | |
412 | assumed that vfork tracing is available whenever fork tracing | |
413 | is available. */ | |
414 | ret = ptrace (PTRACE_CONT, child_pid, (PTRACE_TYPE_ARG3) 0, | |
415 | (PTRACE_TYPE_ARG4) 0); | |
416 | if (ret != 0) | |
8ae377e8 | 417 | warning (_("linux_test_for_tracefork: failed to resume child")); |
96d7229d LM |
418 | |
419 | ret = my_waitpid (child_pid, &status, 0); | |
420 | ||
421 | /* Check if we received a fork event notification. */ | |
422 | if (ret == child_pid && WIFSTOPPED (status) | |
423 | && status >> 16 == PTRACE_EVENT_FORK) | |
424 | { | |
425 | /* We did receive a fork event notification. Make sure its PID | |
426 | is reported. */ | |
427 | second_pid = 0; | |
428 | ret = ptrace (PTRACE_GETEVENTMSG, child_pid, (PTRACE_TYPE_ARG3) 0, | |
429 | (PTRACE_TYPE_ARG4) &second_pid); | |
430 | if (ret == 0 && second_pid != 0) | |
431 | { | |
432 | int second_status; | |
433 | ||
434 | /* We got the PID from the grandchild, which means fork | |
435 | tracing is supported. */ | |
436 | #ifdef GDBSERVER | |
437 | /* Do not enable all the options for now since gdbserver does not | |
438 | properly support them. This restriction will be lifted when | |
439 | gdbserver is augmented to support them. */ | |
440 | current_ptrace_options |= PTRACE_O_TRACECLONE; | |
441 | #else | |
442 | current_ptrace_options |= PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK | |
443 | | PTRACE_O_TRACECLONE | PTRACE_O_TRACEEXEC; | |
444 | ||
445 | /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to | |
446 | support read-only process state. */ | |
447 | #endif | |
448 | ||
449 | /* Do some cleanup and kill the grandchild. */ | |
450 | my_waitpid (second_pid, &second_status, 0); | |
451 | ret = ptrace (PTRACE_KILL, second_pid, (PTRACE_TYPE_ARG3) 0, | |
452 | (PTRACE_TYPE_ARG4) 0); | |
453 | if (ret != 0) | |
8ae377e8 | 454 | warning (_("linux_test_for_tracefork: " |
96d7229d LM |
455 | "failed to kill second child")); |
456 | my_waitpid (second_pid, &status, 0); | |
457 | } | |
458 | } | |
459 | else | |
8ae377e8 | 460 | warning (_("linux_test_for_tracefork: unexpected result from waitpid " |
96d7229d | 461 | "(%d, status 0x%x)"), ret, status); |
96d7229d LM |
462 | } |
463 | ||
464 | /* Enable reporting of all currently supported ptrace events. */ | |
465 | ||
466 | void | |
467 | linux_enable_event_reporting (pid_t pid) | |
468 | { | |
469 | /* Check if we have initialized the ptrace features for this | |
470 | target. If not, do it now. */ | |
471 | if (current_ptrace_options == -1) | |
472 | linux_check_ptrace_features (); | |
473 | ||
474 | /* Set the options. */ | |
475 | ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, | |
476 | (PTRACE_TYPE_ARG4) (uintptr_t) current_ptrace_options); | |
477 | } | |
478 | ||
c077881a HZ |
479 | /* Disable reporting of all currently supported ptrace events. */ |
480 | ||
481 | void | |
482 | linux_disable_event_reporting (pid_t pid) | |
483 | { | |
484 | /* Set the options. */ | |
485 | ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, 0); | |
486 | } | |
487 | ||
96d7229d LM |
488 | /* Returns non-zero if PTRACE_OPTIONS is contained within |
489 | CURRENT_PTRACE_OPTIONS, therefore supported. Returns 0 | |
490 | otherwise. */ | |
491 | ||
492 | static int | |
493 | ptrace_supports_feature (int ptrace_options) | |
494 | { | |
495 | gdb_assert (current_ptrace_options >= 0); | |
496 | ||
497 | return ((current_ptrace_options & ptrace_options) == ptrace_options); | |
498 | } | |
499 | ||
500 | /* Returns non-zero if PTRACE_EVENT_FORK is supported by ptrace, | |
501 | 0 otherwise. Note that if PTRACE_EVENT_FORK is supported so is | |
502 | PTRACE_EVENT_CLONE, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, | |
503 | since they were all added to the kernel at the same time. */ | |
504 | ||
505 | int | |
506 | linux_supports_tracefork (void) | |
507 | { | |
508 | return ptrace_supports_feature (PTRACE_O_TRACEFORK); | |
509 | } | |
510 | ||
511 | /* Returns non-zero if PTRACE_EVENT_CLONE is supported by ptrace, | |
512 | 0 otherwise. Note that if PTRACE_EVENT_CLONE is supported so is | |
513 | PTRACE_EVENT_FORK, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, | |
514 | since they were all added to the kernel at the same time. */ | |
515 | ||
516 | int | |
517 | linux_supports_traceclone (void) | |
518 | { | |
519 | return ptrace_supports_feature (PTRACE_O_TRACECLONE); | |
520 | } | |
521 | ||
522 | /* Returns non-zero if PTRACE_O_TRACEVFORKDONE is supported by | |
523 | ptrace, 0 otherwise. */ | |
524 | ||
525 | int | |
526 | linux_supports_tracevforkdone (void) | |
527 | { | |
528 | return ptrace_supports_feature (PTRACE_O_TRACEVFORKDONE); | |
529 | } | |
530 | ||
531 | /* Returns non-zero if PTRACE_O_TRACESYSGOOD is supported by ptrace, | |
532 | 0 otherwise. */ | |
533 | ||
534 | int | |
535 | linux_supports_tracesysgood (void) | |
536 | { | |
537 | return ptrace_supports_feature (PTRACE_O_TRACESYSGOOD); | |
538 | } | |
539 | ||
aa7c7447 JK |
540 | /* Display possible problems on this system. Display them only once per GDB |
541 | execution. */ | |
542 | ||
543 | void | |
544 | linux_ptrace_init_warnings (void) | |
545 | { | |
546 | static int warned = 0; | |
547 | ||
548 | if (warned) | |
549 | return; | |
550 | warned = 1; | |
551 | ||
552 | linux_ptrace_test_ret_to_nx (); | |
553 | } |