1 //===-- PlatformLinux.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 "PlatformLinux.h"
10 #include "lldb/Host/Config.h"
11 
12 #include <stdio.h>
13 #if LLDB_ENABLE_POSIX
14 #include <sys/utsname.h>
15 #endif
16 
17 #include "lldb/Core/Debugger.h"
18 #include "lldb/Core/PluginManager.h"
19 #include "lldb/Host/HostInfo.h"
20 #include "lldb/Target/Process.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Utility/FileSpec.h"
23 #include "lldb/Utility/Log.h"
24 #include "lldb/Utility/State.h"
25 #include "lldb/Utility/Status.h"
26 #include "lldb/Utility/StreamString.h"
27 
28 // Define these constants from Linux mman.h for use when targeting remote linux
29 // systems even when host has different values.
30 #define MAP_PRIVATE 2
31 #define MAP_ANON 0x20
32 
33 using namespace lldb;
34 using namespace lldb_private;
35 using namespace lldb_private::platform_linux;
36 
37 LLDB_PLUGIN_DEFINE(PlatformLinux)
38 
39 static uint32_t g_initialize_count = 0;
40 
41 
42 PlatformSP PlatformLinux::CreateInstance(bool force, const ArchSpec *arch) {
43   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
44   LLDB_LOG(log, "force = {0}, arch=({1}, {2})", force,
45            arch ? arch->GetArchitectureName() : "<null>",
46            arch ? arch->GetTriple().getTriple() : "<null>");
47 
48   bool create = force;
49   if (!create && arch && arch->IsValid()) {
50     const llvm::Triple &triple = arch->GetTriple();
51     switch (triple.getOS()) {
52     case llvm::Triple::Linux:
53       create = true;
54       break;
55 
56 #if defined(__linux__)
57     // Only accept "unknown" for the OS if the host is linux and it "unknown"
58     // wasn't specified (it was just returned because it was NOT specified)
59     case llvm::Triple::OSType::UnknownOS:
60       create = !arch->TripleOSWasSpecified();
61       break;
62 #endif
63     default:
64       break;
65     }
66   }
67 
68   LLDB_LOG(log, "create = {0}", create);
69   if (create) {
70     return PlatformSP(new PlatformLinux(false));
71   }
72   return PlatformSP();
73 }
74 
75 ConstString PlatformLinux::GetPluginNameStatic(bool is_host) {
76   if (is_host) {
77     static ConstString g_host_name(Platform::GetHostPlatformName());
78     return g_host_name;
79   } else {
80     static ConstString g_remote_name("remote-linux");
81     return g_remote_name;
82   }
83 }
84 
85 const char *PlatformLinux::GetPluginDescriptionStatic(bool is_host) {
86   if (is_host)
87     return "Local Linux user platform plug-in.";
88   else
89     return "Remote Linux user platform plug-in.";
90 }
91 
92 ConstString PlatformLinux::GetPluginName() {
93   return GetPluginNameStatic(IsHost());
94 }
95 
96 void PlatformLinux::Initialize() {
97   PlatformPOSIX::Initialize();
98 
99   if (g_initialize_count++ == 0) {
100 #if defined(__linux__) && !defined(__ANDROID__)
101     PlatformSP default_platform_sp(new PlatformLinux(true));
102     default_platform_sp->SetSystemArchitecture(HostInfo::GetArchitecture());
103     Platform::SetHostPlatform(default_platform_sp);
104 #endif
105     PluginManager::RegisterPlugin(
106         PlatformLinux::GetPluginNameStatic(false),
107         PlatformLinux::GetPluginDescriptionStatic(false),
108         PlatformLinux::CreateInstance, nullptr);
109   }
110 }
111 
112 void PlatformLinux::Terminate() {
113   if (g_initialize_count > 0) {
114     if (--g_initialize_count == 0) {
115       PluginManager::UnregisterPlugin(PlatformLinux::CreateInstance);
116     }
117   }
118 
119   PlatformPOSIX::Terminate();
120 }
121 
122 /// Default Constructor
123 PlatformLinux::PlatformLinux(bool is_host)
124     : PlatformPOSIX(is_host) // This is the local host platform
125 {}
126 
127 PlatformLinux::~PlatformLinux() = default;
128 
129 bool PlatformLinux::GetSupportedArchitectureAtIndex(uint32_t idx,
130                                                     ArchSpec &arch) {
131   if (IsHost()) {
132     ArchSpec hostArch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
133     if (hostArch.GetTriple().isOSLinux()) {
134       if (idx == 0) {
135         arch = hostArch;
136         return arch.IsValid();
137       } else if (idx == 1) {
138         // If the default host architecture is 64-bit, look for a 32-bit
139         // variant
140         if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit()) {
141           arch = HostInfo::GetArchitecture(HostInfo::eArchKind32);
142           return arch.IsValid();
143         }
144       }
145     }
146   } else {
147     if (m_remote_platform_sp)
148       return m_remote_platform_sp->GetSupportedArchitectureAtIndex(idx, arch);
149 
150     llvm::Triple triple;
151     // Set the OS to linux
152     triple.setOS(llvm::Triple::Linux);
153     // Set the architecture
154     switch (idx) {
155     case 0:
156       triple.setArchName("x86_64");
157       break;
158     case 1:
159       triple.setArchName("i386");
160       break;
161     case 2:
162       triple.setArchName("arm");
163       break;
164     case 3:
165       triple.setArchName("aarch64");
166       break;
167     case 4:
168       triple.setArchName("mips64");
169       break;
170     case 5:
171       triple.setArchName("hexagon");
172       break;
173     case 6:
174       triple.setArchName("mips");
175       break;
176     case 7:
177       triple.setArchName("mips64el");
178       break;
179     case 8:
180       triple.setArchName("mipsel");
181       break;
182     case 9:
183       triple.setArchName("s390x");
184       break;
185     default:
186       return false;
187     }
188     // Leave the vendor as "llvm::Triple:UnknownVendor" and don't specify the
189     // vendor by calling triple.SetVendorName("unknown") so that it is a
190     // "unspecified unknown". This means when someone calls
191     // triple.GetVendorName() it will return an empty string which indicates
192     // that the vendor can be set when two architectures are merged
193 
194     // Now set the triple into "arch" and return true
195     arch.SetTriple(triple);
196     return true;
197   }
198   return false;
199 }
200 
201 void PlatformLinux::GetStatus(Stream &strm) {
202   Platform::GetStatus(strm);
203 
204 #if LLDB_ENABLE_POSIX
205   // Display local kernel information only when we are running in host mode.
206   // Otherwise, we would end up printing non-Linux information (when running on
207   // Mac OS for example).
208   if (IsHost()) {
209     struct utsname un;
210 
211     if (uname(&un))
212       return;
213 
214     strm.Printf("    Kernel: %s\n", un.sysname);
215     strm.Printf("   Release: %s\n", un.release);
216     strm.Printf("   Version: %s\n", un.version);
217   }
218 #endif
219 }
220 
221 int32_t
222 PlatformLinux::GetResumeCountForLaunchInfo(ProcessLaunchInfo &launch_info) {
223   int32_t resume_count = 0;
224 
225   // Always resume past the initial stop when we use eLaunchFlagDebug
226   if (launch_info.GetFlags().Test(eLaunchFlagDebug)) {
227     // Resume past the stop for the final exec into the true inferior.
228     ++resume_count;
229   }
230 
231   // If we're not launching a shell, we're done.
232   const FileSpec &shell = launch_info.GetShell();
233   if (!shell)
234     return resume_count;
235 
236   std::string shell_string = shell.GetPath();
237   // We're in a shell, so for sure we have to resume past the shell exec.
238   ++resume_count;
239 
240   // Figure out what shell we're planning on using.
241   const char *shell_name = strrchr(shell_string.c_str(), '/');
242   if (shell_name == nullptr)
243     shell_name = shell_string.c_str();
244   else
245     shell_name++;
246 
247   if (strcmp(shell_name, "csh") == 0 || strcmp(shell_name, "tcsh") == 0 ||
248       strcmp(shell_name, "zsh") == 0 || strcmp(shell_name, "sh") == 0) {
249     // These shells seem to re-exec themselves.  Add another resume.
250     ++resume_count;
251   }
252 
253   return resume_count;
254 }
255 
256 bool PlatformLinux::CanDebugProcess() {
257   if (IsHost()) {
258     return true;
259   } else {
260     // If we're connected, we can debug.
261     return IsConnected();
262   }
263 }
264 
265 void PlatformLinux::CalculateTrapHandlerSymbolNames() {
266   m_trap_handlers.push_back(ConstString("_sigtramp"));
267   m_trap_handlers.push_back(ConstString("__kernel_rt_sigreturn"));
268   m_trap_handlers.push_back(ConstString("__restore_rt"));
269 }
270 
271 MmapArgList PlatformLinux::GetMmapArgumentList(const ArchSpec &arch,
272                                                addr_t addr, addr_t length,
273                                                unsigned prot, unsigned flags,
274                                                addr_t fd, addr_t offset) {
275   uint64_t flags_platform = 0;
276   uint64_t map_anon = arch.IsMIPS() ? 0x800 : MAP_ANON;
277 
278   if (flags & eMmapFlagsPrivate)
279     flags_platform |= MAP_PRIVATE;
280   if (flags & eMmapFlagsAnon)
281     flags_platform |= map_anon;
282 
283   MmapArgList args({addr, length, prot, flags_platform, fd, offset});
284   return args;
285 }
286 
287