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@ -300,20 +300,6 @@ linux_fork_to_function (gdb_byte *child_stack, int (*function) (void *)) |
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return child_pid; |
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} |
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/* A helper function for linux_check_ptrace_features, called after
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the child forks a grandchild. */ |
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static int |
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linux_grandchild_function (void *child_stack) |
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{ |
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/* Free any allocated stack. */ |
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xfree (child_stack); |
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/* This code is only reacheable by the grandchild (child's child)
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process. */ |
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_exit (0); |
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} |
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/* A helper function for linux_check_ptrace_features, called after
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the parent process forks a child. The child allows itself to |
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be traced by its parent. */ |
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@ -324,16 +310,11 @@ linux_child_function (void *child_stack) |
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ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0); |
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kill (getpid (), SIGSTOP); |
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/* Fork a grandchild. */ |
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linux_fork_to_function ((gdb_byte *) child_stack, linux_grandchild_function); |
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/* This code is only reacheable by the child (grandchild's parent)
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process. */ |
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_exit (0); |
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} |
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static void linux_test_for_tracesysgood (int child_pid); |
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static void linux_test_for_tracefork (int child_pid); |
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static void linux_test_for_exitkill (int child_pid); |
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/* Determine ptrace features available on this target. */ |
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@ -343,8 +324,15 @@ linux_check_ptrace_features (void) |
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{ |
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int child_pid, ret, status; |
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/* Initialize the options. */ |
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supported_ptrace_options = 0; |
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/* Initialize the options. We consider that these options are always
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supported. */ |
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supported_ptrace_options |
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= (PTRACE_O_TRACESYSGOOD |
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| PTRACE_O_TRACECLONE |
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| PTRACE_O_TRACEFORK |
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| PTRACE_O_TRACEVFORK |
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| PTRACE_O_TRACEVFORKDONE |
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| PTRACE_O_TRACEEXEC); |
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/* Fork a child so we can do some testing. The child will call
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linux_child_function and will get traced. The child will |
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@ -362,104 +350,12 @@ linux_check_ptrace_features (void) |
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error (_("linux_check_ptrace_features: waitpid: unexpected status %d."), |
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status); |
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linux_test_for_tracesysgood (child_pid); |
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linux_test_for_tracefork (child_pid); |
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linux_test_for_exitkill (child_pid); |
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/* Kill child_pid. */ |
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kill_child (child_pid, "linux_check_ptrace_features"); |
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} |
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/* Determine if PTRACE_O_TRACESYSGOOD can be used to catch
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syscalls. */ |
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static void |
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linux_test_for_tracesysgood (int child_pid) |
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{ |
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int ret; |
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ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, |
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(PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD); |
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if (ret == 0) |
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supported_ptrace_options |= PTRACE_O_TRACESYSGOOD; |
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} |
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/* Determine if PTRACE_O_TRACEFORK can be used to follow fork
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events. */ |
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static void |
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linux_test_for_tracefork (int child_pid) |
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{ |
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int ret, status; |
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long second_pid; |
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/* First, set the PTRACE_O_TRACEFORK option. If this fails, we
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know for sure that it is not supported. */ |
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ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, |
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(PTRACE_TYPE_ARG4) PTRACE_O_TRACEFORK); |
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if (ret != 0) |
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return; |
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/* Check if the target supports PTRACE_O_TRACEVFORKDONE. */ |
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ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0, |
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(PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK |
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| PTRACE_O_TRACEVFORKDONE)); |
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if (ret == 0) |
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supported_ptrace_options |= PTRACE_O_TRACEVFORKDONE; |
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/* Setting PTRACE_O_TRACEFORK did not cause an error, however we
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don't know for sure that the feature is available; old |
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versions of PTRACE_SETOPTIONS ignored unknown options. |
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Therefore, we attach to the child process, use PTRACE_SETOPTIONS |
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to enable fork tracing, and let it fork. If the process exits, |
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we assume that we can't use PTRACE_O_TRACEFORK; if we get the |
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fork notification, and we can extract the new child's PID, then |
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we assume that we can. |
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We do not explicitly check for vfork tracing here. It is |
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assumed that vfork tracing is available whenever fork tracing |
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is available. */ |
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ret = ptrace (PTRACE_CONT, child_pid, (PTRACE_TYPE_ARG3) 0, |
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(PTRACE_TYPE_ARG4) 0); |
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if (ret != 0) |
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warning (_("linux_test_for_tracefork: failed to resume child")); |
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ret = my_waitpid (child_pid, &status, 0); |
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/* Check if we received a fork event notification. */ |
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if (ret == child_pid && WIFSTOPPED (status) |
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&& linux_ptrace_get_extended_event (status) == PTRACE_EVENT_FORK) |
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{ |
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/* We did receive a fork event notification. Make sure its PID
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is reported. */ |
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second_pid = 0; |
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ret = ptrace (PTRACE_GETEVENTMSG, child_pid, (PTRACE_TYPE_ARG3) 0, |
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(PTRACE_TYPE_ARG4) &second_pid); |
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if (ret == 0 && second_pid != 0) |
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{ |
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int second_status; |
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/* We got the PID from the grandchild, which means fork
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tracing is supported. */ |
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supported_ptrace_options |= PTRACE_O_TRACECLONE; |
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supported_ptrace_options |= (PTRACE_O_TRACEFORK |
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| PTRACE_O_TRACEVFORK |
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| PTRACE_O_TRACEEXEC); |
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/* Do some cleanup and kill the grandchild. */ |
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my_waitpid (second_pid, &second_status, 0); |
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kill_child (second_pid, "linux_test_for_tracefork"); |
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} |
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} |
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else |
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warning (_("linux_test_for_tracefork: unexpected result from waitpid " |
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"(%d, status 0x%x)"), ret, status); |
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} |
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/* Determine if PTRACE_O_EXITKILL can be used. */ |
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static void |
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@ -507,70 +403,6 @@ linux_disable_event_reporting (pid_t pid) |
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ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0, 0); |
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} |
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/* Returns non-zero if PTRACE_OPTIONS is contained within
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SUPPORTED_PTRACE_OPTIONS, therefore supported. Returns 0 |
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otherwise. */ |
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static int |
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ptrace_supports_feature (int ptrace_options) |
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{ |
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if (supported_ptrace_options == -1) |
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linux_check_ptrace_features (); |
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return ((supported_ptrace_options & ptrace_options) == ptrace_options); |
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} |
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/* Returns non-zero if PTRACE_EVENT_FORK is supported by ptrace,
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0 otherwise. Note that if PTRACE_EVENT_FORK is supported so is |
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PTRACE_EVENT_CLONE, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, |
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since they were all added to the kernel at the same time. */ |
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int |
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linux_supports_tracefork (void) |
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{ |
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return ptrace_supports_feature (PTRACE_O_TRACEFORK); |
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} |
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/* Returns non-zero if PTRACE_EVENT_EXEC is supported by ptrace,
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0 otherwise. Note that if PTRACE_EVENT_FORK is supported so is |
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PTRACE_EVENT_CLONE, PTRACE_EVENT_FORK and PTRACE_EVENT_VFORK, |
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since they were all added to the kernel at the same time. */ |
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int |
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linux_supports_traceexec (void) |
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{ |
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return ptrace_supports_feature (PTRACE_O_TRACEEXEC); |
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} |
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/* Returns non-zero if PTRACE_EVENT_CLONE is supported by ptrace,
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0 otherwise. Note that if PTRACE_EVENT_CLONE is supported so is |
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PTRACE_EVENT_FORK, PTRACE_EVENT_EXEC and PTRACE_EVENT_VFORK, |
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since they were all added to the kernel at the same time. */ |
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int |
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linux_supports_traceclone (void) |
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{ |
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return ptrace_supports_feature (PTRACE_O_TRACECLONE); |
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} |
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/* Returns non-zero if PTRACE_O_TRACEVFORKDONE is supported by
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ptrace, 0 otherwise. */ |
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int |
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linux_supports_tracevforkdone (void) |
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{ |
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return ptrace_supports_feature (PTRACE_O_TRACEVFORKDONE); |
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} |
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/* Returns non-zero if PTRACE_O_TRACESYSGOOD is supported by ptrace,
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0 otherwise. */ |
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int |
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linux_supports_tracesysgood (void) |
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{ |
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return ptrace_supports_feature (PTRACE_O_TRACESYSGOOD); |
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} |
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/* Display possible problems on this system. Display them only once per GDB
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execution. */ |
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Simon Marchi
5 years ago