1//===-- ProcessFreeBSDKernel.cpp ------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Core/Module.h"
10#include "lldb/Core/PluginManager.h"
11#include "lldb/Target/DynamicLoader.h"
12
13#include "Plugins/DynamicLoader/FreeBSD-Kernel/DynamicLoaderFreeBSDKernel.h"
14#include "ProcessFreeBSDKernel.h"
15#include "ThreadFreeBSDKernel.h"
16
17#if LLDB_ENABLE_FBSDVMCORE
18#include <fvc.h>
19#endif
20#if defined(__FreeBSD__)
21#include <kvm.h>
22#endif
23
24using namespace lldb;
25using namespace lldb_private;
26
27LLDB_PLUGIN_DEFINE(ProcessFreeBSDKernel)
28
29namespace {
30
31#if LLDB_ENABLE_FBSDVMCORE
32class ProcessFreeBSDKernelFVC : public ProcessFreeBSDKernel {
33public:
34 ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp, lldb::ListenerSP listener,
35 fvc_t *fvc, const FileSpec &core_file);
36
37 ~ProcessFreeBSDKernelFVC();
38
39 size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
40 lldb_private::Status &error) override;
41
42private:
43 fvc_t *m_fvc;
44
45 const char *GetError();
46};
47#endif // LLDB_ENABLE_FBSDVMCORE
48
49#if defined(__FreeBSD__)
50class ProcessFreeBSDKernelKVM : public ProcessFreeBSDKernel {
51public:
52 ProcessFreeBSDKernelKVM(lldb::TargetSP target_sp, lldb::ListenerSP listener,
53 kvm_t *fvc, const FileSpec &core_file);
54
55 ~ProcessFreeBSDKernelKVM();
56
57 size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
58 lldb_private::Status &error) override;
59
60private:
61 kvm_t *m_kvm;
62
63 const char *GetError();
64};
65#endif // defined(__FreeBSD__)
66
67} // namespace
68
69ProcessFreeBSDKernel::ProcessFreeBSDKernel(lldb::TargetSP target_sp,
70 ListenerSP listener_sp,
71 const FileSpec &core_file)
72 : PostMortemProcess(target_sp, listener_sp, core_file) {}
73
74lldb::ProcessSP ProcessFreeBSDKernel::CreateInstance(lldb::TargetSP target_sp,
75 ListenerSP listener_sp,
76 const FileSpec *crash_file,
77 bool can_connect) {
78 ModuleSP executable = target_sp->GetExecutableModule();
79 if (crash_file && !can_connect && executable) {
80#if LLDB_ENABLE_FBSDVMCORE
81 fvc_t *fvc =
82 fvc_open(executable->GetFileSpec().GetPath().c_str(),
83 crash_file->GetPath().c_str(), nullptr, nullptr, nullptr);
84 if (fvc)
85 return std::make_shared<ProcessFreeBSDKernelFVC>(target_sp, listener_sp,
86 fvc, *crash_file);
87#endif
88
89#if defined(__FreeBSD__)
90 kvm_t *kvm =
91 kvm_open2(executable->GetFileSpec().GetPath().c_str(),
92 crash_file->GetPath().c_str(), O_RDONLY, nullptr, nullptr);
93 if (kvm)
94 return std::make_shared<ProcessFreeBSDKernelKVM>(target_sp, listener_sp,
95 kvm, *crash_file);
96#endif
97 }
98 return nullptr;
99}
100
101void ProcessFreeBSDKernel::Initialize() {
102 static llvm::once_flag g_once_flag;
103
104 llvm::call_once(flag&: g_once_flag, F: []() {
105 PluginManager::RegisterPlugin(name: GetPluginNameStatic(),
106 description: GetPluginDescriptionStatic(), create_callback: CreateInstance);
107 });
108}
109
110void ProcessFreeBSDKernel::Terminate() {
111 PluginManager::UnregisterPlugin(create_callback: ProcessFreeBSDKernel::CreateInstance);
112}
113
114Status ProcessFreeBSDKernel::DoDestroy() { return Status(); }
115
116bool ProcessFreeBSDKernel::CanDebug(lldb::TargetSP target_sp,
117 bool plugin_specified_by_name) {
118 return true;
119}
120
121void ProcessFreeBSDKernel::RefreshStateAfterStop() {}
122
123bool ProcessFreeBSDKernel::DoUpdateThreadList(ThreadList &old_thread_list,
124 ThreadList &new_thread_list) {
125 if (old_thread_list.GetSize(can_update: false) == 0) {
126 // Make up the thread the first time this is called so we can set our one
127 // and only core thread state up.
128
129 // We cannot construct a thread without a register context as that crashes
130 // LLDB but we can construct a process without threads to provide minimal
131 // memory reading support.
132 switch (GetTarget().GetArchitecture().GetMachine()) {
133 case llvm::Triple::aarch64:
134 case llvm::Triple::x86:
135 case llvm::Triple::x86_64:
136 break;
137 default:
138 return false;
139 }
140
141 Status error;
142
143 // struct field offsets are written as symbols so that we don't have
144 // to figure them out ourselves
145 int32_t offset_p_list = ReadSignedIntegerFromMemory(
146 load_addr: FindSymbol(name: "proc_off_p_list"), byte_size: 4, fail_value: -1, error);
147 int32_t offset_p_pid =
148 ReadSignedIntegerFromMemory(load_addr: FindSymbol(name: "proc_off_p_pid"), byte_size: 4, fail_value: -1, error);
149 int32_t offset_p_threads = ReadSignedIntegerFromMemory(
150 load_addr: FindSymbol(name: "proc_off_p_threads"), byte_size: 4, fail_value: -1, error);
151 int32_t offset_p_comm = ReadSignedIntegerFromMemory(
152 load_addr: FindSymbol(name: "proc_off_p_comm"), byte_size: 4, fail_value: -1, error);
153
154 int32_t offset_td_tid = ReadSignedIntegerFromMemory(
155 load_addr: FindSymbol(name: "thread_off_td_tid"), byte_size: 4, fail_value: -1, error);
156 int32_t offset_td_plist = ReadSignedIntegerFromMemory(
157 load_addr: FindSymbol(name: "thread_off_td_plist"), byte_size: 4, fail_value: -1, error);
158 int32_t offset_td_pcb = ReadSignedIntegerFromMemory(
159 load_addr: FindSymbol(name: "thread_off_td_pcb"), byte_size: 4, fail_value: -1, error);
160 int32_t offset_td_oncpu = ReadSignedIntegerFromMemory(
161 load_addr: FindSymbol(name: "thread_off_td_oncpu"), byte_size: 4, fail_value: -1, error);
162 int32_t offset_td_name = ReadSignedIntegerFromMemory(
163 load_addr: FindSymbol(name: "thread_off_td_name"), byte_size: 4, fail_value: -1, error);
164
165 // fail if we were not able to read any of the offsets
166 if (offset_p_list == -1 || offset_p_pid == -1 || offset_p_threads == -1 ||
167 offset_p_comm == -1 || offset_td_tid == -1 || offset_td_plist == -1 ||
168 offset_td_pcb == -1 || offset_td_oncpu == -1 || offset_td_name == -1)
169 return false;
170
171 // dumptid contains the thread-id of the crashing thread
172 // dumppcb contains its PCB
173 int32_t dumptid =
174 ReadSignedIntegerFromMemory(load_addr: FindSymbol(name: "dumptid"), byte_size: 4, fail_value: -1, error);
175 lldb::addr_t dumppcb = FindSymbol(name: "dumppcb");
176
177 // stoppcbs is an array of PCBs on all CPUs
178 // each element is of size pcb_size
179 int32_t pcbsize =
180 ReadSignedIntegerFromMemory(load_addr: FindSymbol(name: "pcb_size"), byte_size: 4, fail_value: -1, error);
181 lldb::addr_t stoppcbs = FindSymbol(name: "stoppcbs");
182
183 // from FreeBSD sys/param.h
184 constexpr size_t fbsd_maxcomlen = 19;
185
186 // iterate through a linked list of all processes
187 // allproc is a pointer to the first list element, p_list field
188 // (found at offset_p_list) specifies the next element
189 for (lldb::addr_t proc =
190 ReadPointerFromMemory(vm_addr: FindSymbol(name: "allproc"), error);
191 proc != 0 && proc != LLDB_INVALID_ADDRESS;
192 proc = ReadPointerFromMemory(vm_addr: proc + offset_p_list, error)) {
193 int32_t pid =
194 ReadSignedIntegerFromMemory(load_addr: proc + offset_p_pid, byte_size: 4, fail_value: -1, error);
195 // process' command-line string
196 char comm[fbsd_maxcomlen + 1];
197 ReadCStringFromMemory(vm_addr: proc + offset_p_comm, cstr: comm, cstr_max_len: sizeof(comm), error);
198
199 // iterate through a linked list of all process' threads
200 // the initial thread is found in process' p_threads, subsequent
201 // elements are linked via td_plist field
202 for (lldb::addr_t td =
203 ReadPointerFromMemory(vm_addr: proc + offset_p_threads, error);
204 td != 0; td = ReadPointerFromMemory(vm_addr: td + offset_td_plist, error)) {
205 int32_t tid =
206 ReadSignedIntegerFromMemory(load_addr: td + offset_td_tid, byte_size: 4, fail_value: -1, error);
207 lldb::addr_t pcb_addr =
208 ReadPointerFromMemory(vm_addr: td + offset_td_pcb, error);
209 // whether process was on CPU (-1 if not, otherwise CPU number)
210 int32_t oncpu =
211 ReadSignedIntegerFromMemory(load_addr: td + offset_td_oncpu, byte_size: 4, fail_value: -2, error);
212 // thread name
213 char thread_name[fbsd_maxcomlen + 1];
214 ReadCStringFromMemory(vm_addr: td + offset_td_name, cstr: thread_name,
215 cstr_max_len: sizeof(thread_name), error);
216
217 // if we failed to read TID, ignore this thread
218 if (tid == -1)
219 continue;
220
221 std::string thread_desc = llvm::formatv(Fmt: "(pid {0}) {1}", Vals&: pid, Vals&: comm);
222 if (*thread_name && strcmp(s1: thread_name, s2: comm)) {
223 thread_desc += '/';
224 thread_desc += thread_name;
225 }
226
227 // roughly:
228 // 1. if the thread crashed, its PCB is going to be at "dumppcb"
229 // 2. if the thread was on CPU, its PCB is going to be on the CPU
230 // 3. otherwise, its PCB is in the thread struct
231 if (tid == dumptid) {
232 // NB: dumppcb can be LLDB_INVALID_ADDRESS if reading it failed
233 pcb_addr = dumppcb;
234 thread_desc += " (crashed)";
235 } else if (oncpu != -1) {
236 // if we managed to read stoppcbs and pcb_size, use them to find
237 // the correct PCB
238 if (stoppcbs != LLDB_INVALID_ADDRESS && pcbsize > 0)
239 pcb_addr = stoppcbs + oncpu * pcbsize;
240 else
241 pcb_addr = LLDB_INVALID_ADDRESS;
242 thread_desc += llvm::formatv(Fmt: " (on CPU {0})", Vals&: oncpu);
243 }
244
245 ThreadSP thread_sp{
246 new ThreadFreeBSDKernel(*this, tid, pcb_addr, thread_desc)};
247 new_thread_list.AddThread(thread_sp);
248 }
249 }
250 } else {
251 const uint32_t num_threads = old_thread_list.GetSize(can_update: false);
252 for (uint32_t i = 0; i < num_threads; ++i)
253 new_thread_list.AddThread(thread_sp: old_thread_list.GetThreadAtIndex(idx: i, can_update: false));
254 }
255 return new_thread_list.GetSize(can_update: false) > 0;
256}
257
258Status ProcessFreeBSDKernel::DoLoadCore() {
259 // The core is already loaded by CreateInstance().
260 return Status();
261}
262
263DynamicLoader *ProcessFreeBSDKernel::GetDynamicLoader() {
264 if (m_dyld_up.get() == nullptr)
265 m_dyld_up.reset(p: DynamicLoader::FindPlugin(
266 process: this, plugin_name: DynamicLoaderFreeBSDKernel::GetPluginNameStatic()));
267 return m_dyld_up.get();
268}
269
270lldb::addr_t ProcessFreeBSDKernel::FindSymbol(const char *name) {
271 ModuleSP mod_sp = GetTarget().GetExecutableModule();
272 const Symbol *sym = mod_sp->FindFirstSymbolWithNameAndType(name: ConstString(name));
273 return sym ? sym->GetLoadAddress(target: &GetTarget()) : LLDB_INVALID_ADDRESS;
274}
275
276#if LLDB_ENABLE_FBSDVMCORE
277
278ProcessFreeBSDKernelFVC::ProcessFreeBSDKernelFVC(lldb::TargetSP target_sp,
279 ListenerSP listener_sp,
280 fvc_t *fvc,
281 const FileSpec &core_file)
282 : ProcessFreeBSDKernel(target_sp, listener_sp, crash_file), m_fvc(fvc) {}
283
284ProcessFreeBSDKernelFVC::~ProcessFreeBSDKernelFVC() {
285 if (m_fvc)
286 fvc_close(m_fvc);
287}
288
289size_t ProcessFreeBSDKernelFVC::DoReadMemory(lldb::addr_t addr, void *buf,
290 size_t size, Status &error) {
291 ssize_t rd = 0;
292 rd = fvc_read(m_fvc, addr, buf, size);
293 if (rd < 0 || static_cast<size_t>(rd) != size) {
294 error = Status::FromErrorStringWithFormat("Reading memory failed: %s",
295 GetError());
296 return rd > 0 ? rd : 0;
297 }
298 return rd;
299}
300
301const char *ProcessFreeBSDKernelFVC::GetError() { return fvc_geterr(m_fvc); }
302
303#endif // LLDB_ENABLE_FBSDVMCORE
304
305#if defined(__FreeBSD__)
306
307ProcessFreeBSDKernelKVM::ProcessFreeBSDKernelKVM(lldb::TargetSP target_sp,
308 ListenerSP listener_sp,
309 kvm_t *fvc,
310 const FileSpec &core_file)
311 : ProcessFreeBSDKernel(target_sp, listener_sp, core_file), m_kvm(fvc) {}
312
313ProcessFreeBSDKernelKVM::~ProcessFreeBSDKernelKVM() {
314 if (m_kvm)
315 kvm_close(m_kvm);
316}
317
318size_t ProcessFreeBSDKernelKVM::DoReadMemory(lldb::addr_t addr, void *buf,
319 size_t size, Status &error) {
320 ssize_t rd = 0;
321 rd = kvm_read2(m_kvm, addr, buf, size);
322 if (rd < 0 || static_cast<size_t>(rd) != size) {
323 error = Status::FromErrorStringWithFormat("Reading memory failed: %s",
324 GetError());
325 return rd > 0 ? rd : 0;
326 }
327 return rd;
328}
329
330const char *ProcessFreeBSDKernelKVM::GetError() { return kvm_geterr(m_kvm); }
331
332#endif // defined(__FreeBSD__)
333

source code of lldb/source/Plugins/Process/FreeBSDKernel/ProcessFreeBSDKernel.cpp