1 //===-- HostInfoPosix.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/Host/posix/HostInfoPosix.h"
10 #include "lldb/Utility/Log.h"
11 #include "lldb/Utility/UserIDResolver.h"
12 
13 #include "llvm/ADT/SmallString.h"
14 #include "llvm/ADT/Twine.h"
15 #include "llvm/Support/Path.h"
16 #include "llvm/Support/raw_ostream.h"
17 
18 #include <climits>
19 #include <cstdlib>
20 #include <grp.h>
21 #include <mutex>
22 #include <pwd.h>
23 #include <sys/types.h>
24 #include <sys/utsname.h>
25 #include <unistd.h>
26 
27 using namespace lldb_private;
28 
29 size_t HostInfoPosix::GetPageSize() { return ::getpagesize(); }
30 
31 bool HostInfoPosix::GetHostname(std::string &s) {
32   char hostname[PATH_MAX];
33   hostname[sizeof(hostname) - 1] = '\0';
34   if (::gethostname(hostname, sizeof(hostname) - 1) == 0) {
35     s.assign(hostname);
36     return true;
37   }
38   return false;
39 }
40 
41 llvm::Optional<std::string> HostInfoPosix::GetOSKernelDescription() {
42   struct utsname un;
43   if (uname(&un) < 0)
44     return llvm::None;
45 
46   return std::string(un.version);
47 }
48 
49 #ifdef __ANDROID__
50 #include <android/api-level.h>
51 #endif
52 #if defined(__ANDROID_API__) && __ANDROID_API__ < 21
53 #define USE_GETPWUID
54 #endif
55 
56 namespace {
57 class PosixUserIDResolver : public UserIDResolver {
58 protected:
59   llvm::Optional<std::string> DoGetUserName(id_t uid) override;
60   llvm::Optional<std::string> DoGetGroupName(id_t gid) override;
61 };
62 } // namespace
63 
64 struct PasswdEntry {
65   std::string username;
66   std::string shell;
67 };
68 
69 static llvm::Optional<PasswdEntry> GetPassword(id_t uid) {
70 #ifdef USE_GETPWUID
71   // getpwuid_r is missing from android-9
72   // The caller should provide some thread safety by making sure no one calls
73   // this function concurrently, because using getpwuid is ultimately not
74   // thread-safe as we don't know who else might be calling it.
75   if (auto *user_info_ptr = ::getpwuid(uid))
76     return PasswdEntry{user_info_ptr->pw_name, user_info_ptr->pw_shell};
77 #else
78   struct passwd user_info;
79   struct passwd *user_info_ptr = &user_info;
80   char user_buffer[PATH_MAX];
81   size_t user_buffer_size = sizeof(user_buffer);
82   if (::getpwuid_r(uid, &user_info, user_buffer, user_buffer_size,
83                    &user_info_ptr) == 0 &&
84       user_info_ptr) {
85     return PasswdEntry{user_info_ptr->pw_name, user_info_ptr->pw_shell};
86   }
87 #endif
88   return llvm::None;
89 }
90 
91 llvm::Optional<std::string> PosixUserIDResolver::DoGetUserName(id_t uid) {
92   if (llvm::Optional<PasswdEntry> password = GetPassword(uid))
93     return password->username;
94   return llvm::None;
95 }
96 
97 llvm::Optional<std::string> PosixUserIDResolver::DoGetGroupName(id_t gid) {
98 #ifndef __ANDROID__
99   char group_buffer[PATH_MAX];
100   size_t group_buffer_size = sizeof(group_buffer);
101   struct group group_info;
102   struct group *group_info_ptr = &group_info;
103   // Try the threadsafe version first
104   if (::getgrgid_r(gid, &group_info, group_buffer, group_buffer_size,
105                    &group_info_ptr) == 0) {
106     if (group_info_ptr)
107       return std::string(group_info_ptr->gr_name);
108   } else {
109     // The threadsafe version isn't currently working for me on darwin, but the
110     // non-threadsafe version is, so I am calling it below.
111     group_info_ptr = ::getgrgid(gid);
112     if (group_info_ptr)
113       return std::string(group_info_ptr->gr_name);
114   }
115 #endif
116   return llvm::None;
117 }
118 
119 static llvm::ManagedStatic<PosixUserIDResolver> g_user_id_resolver;
120 
121 UserIDResolver &HostInfoPosix::GetUserIDResolver() {
122   return *g_user_id_resolver;
123 }
124 
125 uint32_t HostInfoPosix::GetUserID() { return getuid(); }
126 
127 uint32_t HostInfoPosix::GetGroupID() { return getgid(); }
128 
129 uint32_t HostInfoPosix::GetEffectiveUserID() { return geteuid(); }
130 
131 uint32_t HostInfoPosix::GetEffectiveGroupID() { return getegid(); }
132 
133 FileSpec HostInfoPosix::GetDefaultShell() {
134   if (const char *v = ::getenv("SHELL"))
135     return FileSpec(v);
136   if (llvm::Optional<PasswdEntry> password = GetPassword(::geteuid()))
137     return FileSpec(password->shell);
138   return FileSpec("/bin/sh");
139 }
140 
141 bool HostInfoPosix::ComputeSupportExeDirectory(FileSpec &file_spec) {
142   return ComputePathRelativeToLibrary(file_spec, "/bin");
143 }
144 
145 bool HostInfoPosix::ComputeHeaderDirectory(FileSpec &file_spec) {
146   FileSpec temp_file("/opt/local/include/lldb");
147   file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
148   return true;
149 }
150 
151 bool HostInfoPosix::GetEnvironmentVar(const std::string &var_name,
152                                       std::string &var) {
153   if (const char *pvar = ::getenv(var_name.c_str())) {
154     var = std::string(pvar);
155     return true;
156   }
157   return false;
158 }
159