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