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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 | ||
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 | ||
46 | tracerpid = linux_proc_get_tracerpid (pid); | |
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 | ||
52 | if (linux_proc_pid_is_zombie (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 | |
6e3c039e | 58 | #if defined __i386__ || defined __x86_64__ |
aa7c7447 JK |
59 | |
60 | /* Address of the 'ret' instruction in asm code block below. */ | |
61 | extern void (linux_ptrace_test_ret_to_nx_instr) (void); | |
62 | ||
63 | #include <sys/reg.h> | |
64 | #include <sys/mman.h> | |
65 | #include <signal.h> | |
aa7c7447 | 66 | |
6e3c039e | 67 | #endif /* defined __i386__ || defined __x86_64__ */ |
aa7c7447 JK |
68 | |
69 | /* Test broken off-trunk Linux kernel patchset for NX support on i386. It was | |
6e3c039e JK |
70 | removed in Fedora kernel 88fa1f0332d188795ed73d7ac2b1564e11a0b4cd. |
71 | ||
72 | Test also x86_64 arch for PaX support. */ | |
aa7c7447 JK |
73 | |
74 | static void | |
75 | linux_ptrace_test_ret_to_nx (void) | |
76 | { | |
6e3c039e | 77 | #if defined __i386__ || defined __x86_64__ |
aa7c7447 JK |
78 | pid_t child, got_pid; |
79 | gdb_byte *return_address, *pc; | |
80 | long l; | |
61a31a67 | 81 | int status, kill_status; |
aa7c7447 JK |
82 | |
83 | return_address = mmap (NULL, 2, PROT_READ | PROT_WRITE, | |
84 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
85 | if (return_address == MAP_FAILED) | |
86 | { | |
87 | warning (_("linux_ptrace_test_ret_to_nx: Cannot mmap: %s"), | |
88 | strerror (errno)); | |
89 | return; | |
90 | } | |
91 | ||
92 | /* Put there 'int3'. */ | |
93 | *return_address = 0xcc; | |
94 | ||
95 | child = fork (); | |
96 | switch (child) | |
97 | { | |
98 | case -1: | |
99 | warning (_("linux_ptrace_test_ret_to_nx: Cannot fork: %s"), | |
100 | strerror (errno)); | |
101 | return; | |
102 | ||
103 | case 0: | |
96d7229d LM |
104 | l = ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) NULL, |
105 | (PTRACE_TYPE_ARG4) NULL); | |
aa7c7447 JK |
106 | if (l != 0) |
107 | warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_TRACEME: %s"), | |
108 | strerror (errno)); | |
109 | else | |
110 | { | |
6e3c039e | 111 | #if defined __i386__ |
aa7c7447 JK |
112 | asm volatile ("pushl %0;" |
113 | ".globl linux_ptrace_test_ret_to_nx_instr;" | |
114 | "linux_ptrace_test_ret_to_nx_instr:" | |
115 | "ret" | |
116 | : : "r" (return_address) : "%esp", "memory"); | |
6e3c039e JK |
117 | #elif defined __x86_64__ |
118 | asm volatile ("pushq %0;" | |
119 | ".globl linux_ptrace_test_ret_to_nx_instr;" | |
120 | "linux_ptrace_test_ret_to_nx_instr:" | |
121 | "ret" | |
bdad4180 MF |
122 | : : "r" ((uint64_t) (uintptr_t) return_address) |
123 | : "%rsp", "memory"); | |
6e3c039e JK |
124 | #else |
125 | # error "!__i386__ && !__x86_64__" | |
126 | #endif | |
aa7c7447 JK |
127 | gdb_assert_not_reached ("asm block did not terminate"); |
128 | } | |
129 | ||
130 | _exit (1); | |
131 | } | |
132 | ||
6e3c039e | 133 | errno = 0; |
aa7c7447 | 134 | got_pid = waitpid (child, &status, 0); |
6e3c039e JK |
135 | if (got_pid != child) |
136 | { | |
137 | warning (_("linux_ptrace_test_ret_to_nx: waitpid returned %ld: %s"), | |
138 | (long) got_pid, strerror (errno)); | |
139 | return; | |
140 | } | |
141 | ||
142 | if (WIFSIGNALED (status)) | |
143 | { | |
144 | if (WTERMSIG (status) != SIGKILL) | |
145 | warning (_("linux_ptrace_test_ret_to_nx: WTERMSIG %d is not SIGKILL!"), | |
146 | (int) WTERMSIG (status)); | |
147 | else | |
148 | warning (_("Cannot call inferior functions, Linux kernel PaX " | |
149 | "protection forbids return to non-executable pages!")); | |
150 | return; | |
151 | } | |
152 | ||
153 | if (!WIFSTOPPED (status)) | |
154 | { | |
155 | warning (_("linux_ptrace_test_ret_to_nx: status %d is not WIFSTOPPED!"), | |
156 | status); | |
157 | return; | |
158 | } | |
aa7c7447 JK |
159 | |
160 | /* We may get SIGSEGV due to missing PROT_EXEC of the return_address. */ | |
6e3c039e JK |
161 | if (WSTOPSIG (status) != SIGTRAP && WSTOPSIG (status) != SIGSEGV) |
162 | { | |
163 | warning (_("linux_ptrace_test_ret_to_nx: " | |
164 | "WSTOPSIG %d is neither SIGTRAP nor SIGSEGV!"), | |
165 | (int) WSTOPSIG (status)); | |
166 | return; | |
167 | } | |
aa7c7447 JK |
168 | |
169 | errno = 0; | |
6e3c039e | 170 | #if defined __i386__ |
96d7229d LM |
171 | l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (EIP * 4), |
172 | (PTRACE_TYPE_ARG4) NULL); | |
6e3c039e | 173 | #elif defined __x86_64__ |
96d7229d LM |
174 | l = ptrace (PTRACE_PEEKUSER, child, (PTRACE_TYPE_ARG3) (uintptr_t) (RIP * 8), |
175 | (PTRACE_TYPE_ARG4) NULL); | |
6e3c039e JK |
176 | #else |
177 | # error "!__i386__ && !__x86_64__" | |
178 | #endif | |
179 | if (errno != 0) | |
180 | { | |
181 | warning (_("linux_ptrace_test_ret_to_nx: Cannot PTRACE_PEEKUSER: %s"), | |
182 | strerror (errno)); | |
183 | return; | |
184 | } | |
aa7c7447 JK |
185 | pc = (void *) (uintptr_t) l; |
186 | ||
61a31a67 | 187 | kill (child, SIGKILL); |
96d7229d LM |
188 | ptrace (PTRACE_KILL, child, (PTRACE_TYPE_ARG3) NULL, |
189 | (PTRACE_TYPE_ARG4) NULL); | |
61a31a67 JK |
190 | |
191 | errno = 0; | |
192 | got_pid = waitpid (child, &kill_status, 0); | |
193 | if (got_pid != child) | |
6e3c039e | 194 | { |
61a31a67 JK |
195 | warning (_("linux_ptrace_test_ret_to_nx: " |
196 | "PTRACE_KILL waitpid returned %ld: %s"), | |
197 | (long) got_pid, strerror (errno)); | |
6e3c039e JK |
198 | return; |
199 | } | |
61a31a67 | 200 | if (!WIFSIGNALED (kill_status)) |
aa7c7447 | 201 | { |
61a31a67 JK |
202 | warning (_("linux_ptrace_test_ret_to_nx: " |
203 | "PTRACE_KILL status %d is not WIFSIGNALED!"), | |
204 | status); | |
205 | return; | |
aa7c7447 JK |
206 | } |
207 | ||
208 | /* + 1 is there as x86* stops after the 'int3' instruction. */ | |
209 | if (WSTOPSIG (status) == SIGTRAP && pc == return_address + 1) | |
210 | { | |
211 | /* PASS */ | |
212 | return; | |
213 | } | |
214 | ||
215 | /* We may get SIGSEGV due to missing PROT_EXEC of the RETURN_ADDRESS page. */ | |
216 | if (WSTOPSIG (status) == SIGSEGV && pc == return_address) | |
217 | { | |
218 | /* PASS */ | |
219 | return; | |
220 | } | |
221 | ||
6e3c039e JK |
222 | if ((void (*) (void)) pc != &linux_ptrace_test_ret_to_nx_instr) |
223 | warning (_("linux_ptrace_test_ret_to_nx: PC %p is neither near return " | |
224 | "address %p nor is the return instruction %p!"), | |
225 | pc, return_address, &linux_ptrace_test_ret_to_nx_instr); | |
226 | else | |
025e6dce PA |
227 | warning (_("Cannot call inferior functions on this system - " |
228 | "Linux kernel with broken i386 NX (non-executable pages) " | |
229 | "support detected!")); | |
6e3c039e | 230 | #endif /* defined __i386__ || defined __x86_64__ */ |
aa7c7447 JK |
231 | } |
232 | ||
96d7229d LM |
233 | /* Helper function to fork a process and make the child process call |
234 | the function FUNCTION, passing CHILD_STACK as parameter. | |
235 | ||
236 | For MMU-less targets, clone is used instead of fork, and | |
237 | CHILD_STACK is used as stack space for the cloned child. If NULL, | |
238 | stack space is allocated via malloc (and subsequently passed to | |
239 | FUNCTION). For MMU targets, CHILD_STACK is ignored. */ | |
240 | ||
241 | static int | |
242 | linux_fork_to_function (gdb_byte *child_stack, void (*function) (gdb_byte *)) | |
243 | { | |
244 | int child_pid; | |
245 | ||
246 | /* Sanity check the function pointer. */ | |
247 | gdb_assert (function != NULL); | |
248 | ||
249 | #if defined(__UCLIBC__) && defined(HAS_NOMMU) | |
250 | #define STACK_SIZE 4096 | |
251 | ||
252 | if (child_stack == NULL) | |
253 | child_stack = xmalloc (STACK_SIZE * 4); | |
254 | ||
255 | /* Use CLONE_VM instead of fork, to support uClinux (no MMU). */ | |
101158d9 | 256 | #ifdef __ia64__ |
96d7229d LM |
257 | child_pid = __clone2 (function, child_stack, STACK_SIZE, |
258 | CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2); | |
101158d9 | 259 | #else /* !__ia64__ */ |
96d7229d LM |
260 | child_pid = clone (function, child_stack + STACK_SIZE, |
261 | CLONE_VM | SIGCHLD, child_stack + STACK_SIZE * 2); | |
101158d9 | 262 | #endif /* !__ia64__ */ |
96d7229d LM |
263 | #else /* !defined(__UCLIBC) && defined(HAS_NOMMU) */ |
264 | child_pid = fork (); | |
265 | ||
266 | if (child_pid == 0) | |
267 | function (NULL); | |
268 | #endif /* defined(__UCLIBC) && defined(HAS_NOMMU) */ | |
269 | ||
270 | if (child_pid == -1) | |
271 | perror_with_name (("fork")); | |
272 | ||
273 | return child_pid; | |
274 | } | |
275 | ||
276 | /* A helper function for linux_check_ptrace_features, called after | |
277 | the child forks a grandchild. */ | |
278 | ||
279 | static void | |
280 | linux_grandchild_function (gdb_byte *child_stack) | |
281 | { | |
282 | /* Free any allocated stack. */ | |
283 | xfree (child_stack); | |
284 | ||
285 | /* This code is only reacheable by the grandchild (child's child) | |
286 | process. */ | |
287 | _exit (0); | |
288 | } | |
289 | ||
290 | /* A helper function for linux_check_ptrace_features, called after | |
291 | the parent process forks a child. The child allows itself to | |
292 | be traced by its parent. */ | |
293 | ||
294 | static void | |
295 | linux_child_function (gdb_byte *child_stack) | |
296 | { | |
297 | ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0); | |
298 | kill (getpid (), SIGSTOP); | |
299 | ||
300 | /* Fork a grandchild. */ | |
301 | linux_fork_to_function (child_stack, linux_grandchild_function); | |
302 | ||
303 | /* This code is only reacheable by the child (grandchild's parent) | |
304 | process. */ | |
305 | _exit (0); | |
306 | } | |
307 | ||
8ae377e8 PA |
308 | static void linux_test_for_tracesysgood (int child_pid); |
309 | static void linux_test_for_tracefork (int child_pid); | |
310 | ||
96d7229d LM |
311 | /* Determine ptrace features available on this target. */ |
312 | ||
313 | static void | |
314 | linux_check_ptrace_features (void) | |
315 | { | |
316 | int child_pid, ret, status; | |
96d7229d LM |
317 | |
318 | /* Initialize the options. */ | |
319 | current_ptrace_options = 0; | |
320 | ||
321 | /* Fork a child so we can do some testing. The child will call | |
322 | linux_child_function and will get traced. The child will | |
323 | eventually fork a grandchild so we can test fork event | |
324 | reporting. */ | |
325 | child_pid = linux_fork_to_function (NULL, linux_child_function); | |
326 | ||
327 | ret = my_waitpid (child_pid, &status, 0); | |
328 | if (ret == -1) | |
329 | perror_with_name (("waitpid")); | |
330 | else if (ret != child_pid) | |
331 | error (_("linux_check_ptrace_features: waitpid: unexpected result %d."), | |
332 | ret); | |
333 | if (! WIFSTOPPED (status)) | |
334 | error (_("linux_check_ptrace_features: waitpid: unexpected status %d."), | |
335 | status); | |
336 | ||
8ae377e8 | 337 | linux_test_for_tracesysgood (child_pid); |
96d7229d | 338 | |
8ae377e8 PA |
339 | linux_test_for_tracefork (child_pid); |
340 | ||
341 | /* Clean things up and kill any pending children. */ | |
342 | do | |
96d7229d LM |
343 | { |
344 | ret = ptrace (PTRACE_KILL, child_pid, (PTRACE_TYPE_ARG3) 0, | |
345 | (PTRACE_TYPE_ARG4) 0); | |
346 | if (ret != 0) | |
8ae377e8 PA |
347 | warning (_("linux_check_ptrace_features: failed to kill child")); |
348 | my_waitpid (child_pid, &status, 0); | |
96d7229d | 349 | } |
8ae377e8 PA |
350 | while (WIFSTOPPED (status)); |
351 | } | |
96d7229d | 352 | |
8ae377e8 PA |
353 | /* Determine if PTRACE_O_TRACESYSGOOD can be used to catch |
354 | syscalls. */ | |
355 | ||
356 | static void | |
357 | linux_test_for_tracesysgood (int child_pid) | |
358 | { | |
8ae377e8 PA |
359 | int ret; |
360 | ||
8009206a TT |
361 | if ((additional_flags & PTRACE_O_TRACESYSGOOD) == 0) |
362 | return; | |
363 | ||
96d7229d LM |
364 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, |
365 | (PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD); | |
8009206a | 366 | |
96d7229d LM |
367 | if (ret == 0) |
368 | current_ptrace_options |= PTRACE_O_TRACESYSGOOD; | |
8ae377e8 | 369 | } |
96d7229d | 370 | |
8ae377e8 PA |
371 | /* Determine if PTRACE_O_TRACEFORK can be used to follow fork |
372 | events. */ | |
373 | ||
374 | static void | |
375 | linux_test_for_tracefork (int child_pid) | |
376 | { | |
377 | int ret, status; | |
378 | long second_pid; | |
379 | ||
380 | /* First, set the PTRACE_O_TRACEFORK option. If this fails, we | |
381 | know for sure that it is not supported. */ | |
382 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, | |
383 | (PTRACE_TYPE_ARG4) PTRACE_O_TRACEFORK); | |
384 | ||
385 | if (ret != 0) | |
386 | return; | |
387 | ||
8009206a TT |
388 | if ((additional_flags & PTRACE_O_TRACEVFORKDONE) != 0) |
389 | { | |
390 | /* Check if the target supports PTRACE_O_TRACEVFORKDONE. */ | |
391 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, | |
392 | (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK | |
393 | | PTRACE_O_TRACEVFORKDONE)); | |
394 | if (ret == 0) | |
395 | current_ptrace_options |= PTRACE_O_TRACEVFORKDONE; | |
396 | } | |
96d7229d LM |
397 | |
398 | /* Setting PTRACE_O_TRACEFORK did not cause an error, however we | |
399 | don't know for sure that the feature is available; old | |
400 | versions of PTRACE_SETOPTIONS ignored unknown options. | |
401 | Therefore, we attach to the child process, use PTRACE_SETOPTIONS | |
402 | to enable fork tracing, and let it fork. If the process exits, | |
403 | we assume that we can't use PTRACE_O_TRACEFORK; if we get the | |
404 | fork notification, and we can extract the new child's PID, then | |
405 | we assume that we can. | |
406 | ||
407 | We do not explicitly check for vfork tracing here. It is | |
408 | assumed that vfork tracing is available whenever fork tracing | |
409 | is available. */ | |
410 | ret = ptrace (PTRACE_CONT, child_pid, (PTRACE_TYPE_ARG3) 0, | |
411 | (PTRACE_TYPE_ARG4) 0); | |
412 | if (ret != 0) | |
8ae377e8 | 413 | warning (_("linux_test_for_tracefork: failed to resume child")); |
96d7229d LM |
414 | |
415 | ret = my_waitpid (child_pid, &status, 0); | |
416 | ||
417 | /* Check if we received a fork event notification. */ | |
418 | if (ret == child_pid && WIFSTOPPED (status) | |
419 | && status >> 16 == PTRACE_EVENT_FORK) | |
420 | { | |
421 | /* We did receive a fork event notification. Make sure its PID | |
422 | is reported. */ | |
423 | second_pid = 0; | |
424 | ret = ptrace (PTRACE_GETEVENTMSG, child_pid, (PTRACE_TYPE_ARG3) 0, | |
425 | (PTRACE_TYPE_ARG4) &second_pid); | |
426 | if (ret == 0 && second_pid != 0) | |
427 | { | |
428 | int second_status; | |
429 | ||
430 | /* We got the PID from the grandchild, which means fork | |
431 | tracing is supported. */ | |
96d7229d | 432 | current_ptrace_options |= PTRACE_O_TRACECLONE; |
8009206a TT |
433 | current_ptrace_options |= (additional_flags & (PTRACE_O_TRACEFORK |
434 | | PTRACE_O_TRACEVFORK | |
435 | | PTRACE_O_TRACEEXEC)); | |
96d7229d LM |
436 | |
437 | /* Do some cleanup and kill the grandchild. */ | |
438 | my_waitpid (second_pid, &second_status, 0); | |
439 | ret = ptrace (PTRACE_KILL, second_pid, (PTRACE_TYPE_ARG3) 0, | |
440 | (PTRACE_TYPE_ARG4) 0); | |
441 | if (ret != 0) | |
8ae377e8 | 442 | warning (_("linux_test_for_tracefork: " |
96d7229d LM |
443 | "failed to kill second child")); |
444 | my_waitpid (second_pid, &status, 0); | |
445 | } | |
446 | } | |
447 | else | |
8ae377e8 | 448 | warning (_("linux_test_for_tracefork: unexpected result from waitpid " |
96d7229d | 449 | "(%d, status 0x%x)"), ret, status); |
96d7229d LM |
450 | } |
451 | ||
452 | /* Enable reporting of all currently supported ptrace events. */ | |
453 | ||
454 | void | |
455 | linux_enable_event_reporting (pid_t pid) | |
456 | { | |
457 | /* Check if we have initialized the ptrace features for this | |
458 | target. If not, do it now. */ | |
459 | if (current_ptrace_options == -1) | |
460 | linux_check_ptrace_features (); | |
461 | ||
462 | /* Set the options. */ | |
463 | ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, | |
464 | (PTRACE_TYPE_ARG4) (uintptr_t) current_ptrace_options); | |
465 | } | |
466 | ||
c077881a HZ |
467 | /* Disable reporting of all currently supported ptrace events. */ |
468 | ||
469 | void | |
470 | linux_disable_event_reporting (pid_t pid) | |
471 | { | |
472 | /* Set the options. */ | |
473 | ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, 0); | |
474 | } | |
475 | ||
96d7229d LM |
476 | /* Returns non-zero if PTRACE_OPTIONS is contained within |
477 | CURRENT_PTRACE_OPTIONS, therefore supported. Returns 0 | |
478 | otherwise. */ | |
479 | ||
480 | static int | |
481 | ptrace_supports_feature (int ptrace_options) | |
482 | { | |
483 | gdb_assert (current_ptrace_options >= 0); | |
484 | ||
485 | return ((current_ptrace_options & ptrace_options) == ptrace_options); | |
486 | } | |
487 | ||
488 | /* Returns non-zero if PTRACE_EVENT_FORK is supported by ptrace, | |
489 | 0 otherwise. Note that if PTRACE_EVENT_FORK is supported so is | |
490 | PTRACE_EVENT_CLONE, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, | |
491 | since they were all added to the kernel at the same time. */ | |
492 | ||
493 | int | |
494 | linux_supports_tracefork (void) | |
495 | { | |
496 | return ptrace_supports_feature (PTRACE_O_TRACEFORK); | |
497 | } | |
498 | ||
499 | /* Returns non-zero if PTRACE_EVENT_CLONE is supported by ptrace, | |
500 | 0 otherwise. Note that if PTRACE_EVENT_CLONE is supported so is | |
501 | PTRACE_EVENT_FORK, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, | |
502 | since they were all added to the kernel at the same time. */ | |
503 | ||
504 | int | |
505 | linux_supports_traceclone (void) | |
506 | { | |
507 | return ptrace_supports_feature (PTRACE_O_TRACECLONE); | |
508 | } | |
509 | ||
510 | /* Returns non-zero if PTRACE_O_TRACEVFORKDONE is supported by | |
511 | ptrace, 0 otherwise. */ | |
512 | ||
513 | int | |
514 | linux_supports_tracevforkdone (void) | |
515 | { | |
516 | return ptrace_supports_feature (PTRACE_O_TRACEVFORKDONE); | |
517 | } | |
518 | ||
519 | /* Returns non-zero if PTRACE_O_TRACESYSGOOD is supported by ptrace, | |
520 | 0 otherwise. */ | |
521 | ||
522 | int | |
523 | linux_supports_tracesysgood (void) | |
524 | { | |
525 | return ptrace_supports_feature (PTRACE_O_TRACESYSGOOD); | |
526 | } | |
527 | ||
aa7c7447 JK |
528 | /* Display possible problems on this system. Display them only once per GDB |
529 | execution. */ | |
530 | ||
531 | void | |
532 | linux_ptrace_init_warnings (void) | |
533 | { | |
534 | static int warned = 0; | |
535 | ||
536 | if (warned) | |
537 | return; | |
538 | warned = 1; | |
539 | ||
540 | linux_ptrace_test_ret_to_nx (); | |
541 | } | |
8009206a TT |
542 | |
543 | /* Set additional ptrace flags to use. Some such flags may be checked | |
544 | by the implementation above. This function must be called before | |
545 | any other function in this file; otherwise the flags may not take | |
546 | effect appropriately. */ | |
547 | ||
548 | void | |
549 | linux_ptrace_set_additional_flags (int flags) | |
550 | { | |
551 | additional_flags = flags; | |
552 | } |