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 <optional>
23 #include <pwd.h>
24 #include <sys/types.h>
25 #include <sys/utsname.h>
26 #include <unistd.h>
27 
28 using namespace lldb_private;
29 
30 size_t HostInfoPosix::GetPageSize() { return ::getpagesize(); }
31 
32 bool HostInfoPosix::GetHostname(std::string &s) {
33   char hostname[PATH_MAX];
34   hostname[sizeof(hostname) - 1] = '\0';
35   if (::gethostname(hostname, sizeof(hostname) - 1) == 0) {
36     s.assign(hostname);
37     return true;
38   }
39   return false;
40 }
41 
42 std::optional<std::string> HostInfoPosix::GetOSKernelDescription() {
43   struct utsname un;
44   if (uname(&un) < 0)
45     return std::nullopt;
46 
47   return std::string(un.version);
48 }
49 
50 #ifdef __ANDROID__
51 #include <android/api-level.h>
52 #endif
53 #if defined(__ANDROID_API__) && __ANDROID_API__ < 21
54 #define USE_GETPWUID
55 #endif
56 
57 namespace {
58 class PosixUserIDResolver : public UserIDResolver {
59 protected:
60   std::optional<std::string> DoGetUserName(id_t uid) override;
61   std::optional<std::string> DoGetGroupName(id_t gid) override;
62 };
63 } // namespace
64 
65 struct PasswdEntry {
66   std::string username;
67   std::string shell;
68 };
69 
70 static std::optional<PasswdEntry> GetPassword(id_t uid) {
71 #ifdef USE_GETPWUID
72   // getpwuid_r is missing from android-9
73   // The caller should provide some thread safety by making sure no one calls
74   // this function concurrently, because using getpwuid is ultimately not
75   // thread-safe as we don't know who else might be calling it.
76   if (auto *user_info_ptr = ::getpwuid(uid))
77     return PasswdEntry{user_info_ptr->pw_name, user_info_ptr->pw_shell};
78 #else
79   struct passwd user_info;
80   struct passwd *user_info_ptr = &user_info;
81   char user_buffer[PATH_MAX];
82   size_t user_buffer_size = sizeof(user_buffer);
83   if (::getpwuid_r(uid, &user_info, user_buffer, user_buffer_size,
84                    &user_info_ptr) == 0 &&
85       user_info_ptr) {
86     return PasswdEntry{user_info_ptr->pw_name, user_info_ptr->pw_shell};
87   }
88 #endif
89   return std::nullopt;
90 }
91 
92 std::optional<std::string> PosixUserIDResolver::DoGetUserName(id_t uid) {
93   if (std::optional<PasswdEntry> password = GetPassword(uid))
94     return password->username;
95   return std::nullopt;
96 }
97 
98 std::optional<std::string> PosixUserIDResolver::DoGetGroupName(id_t gid) {
99 #ifndef __ANDROID__
100   char group_buffer[PATH_MAX];
101   size_t group_buffer_size = sizeof(group_buffer);
102   struct group group_info;
103   struct group *group_info_ptr = &group_info;
104   // Try the threadsafe version first
105   if (::getgrgid_r(gid, &group_info, group_buffer, group_buffer_size,
106                    &group_info_ptr) == 0) {
107     if (group_info_ptr)
108       return std::string(group_info_ptr->gr_name);
109   } else {
110     // The threadsafe version isn't currently working for me on darwin, but the
111     // non-threadsafe version is, so I am calling it below.
112     group_info_ptr = ::getgrgid(gid);
113     if (group_info_ptr)
114       return std::string(group_info_ptr->gr_name);
115   }
116 #endif
117   return std::nullopt;
118 }
119 
120 static llvm::ManagedStatic<PosixUserIDResolver> g_user_id_resolver;
121 
122 UserIDResolver &HostInfoPosix::GetUserIDResolver() {
123   return *g_user_id_resolver;
124 }
125 
126 uint32_t HostInfoPosix::GetUserID() { return getuid(); }
127 
128 uint32_t HostInfoPosix::GetGroupID() { return getgid(); }
129 
130 uint32_t HostInfoPosix::GetEffectiveUserID() { return geteuid(); }
131 
132 uint32_t HostInfoPosix::GetEffectiveGroupID() { return getegid(); }
133 
134 FileSpec HostInfoPosix::GetDefaultShell() {
135   if (const char *v = ::getenv("SHELL"))
136     return FileSpec(v);
137   if (std::optional<PasswdEntry> password = GetPassword(::geteuid()))
138     return FileSpec(password->shell);
139   return FileSpec("/bin/sh");
140 }
141 
142 bool HostInfoPosix::ComputeSupportExeDirectory(FileSpec &file_spec) {
143   return ComputePathRelativeToLibrary(file_spec, "/bin");
144 }
145 
146 bool HostInfoPosix::ComputeHeaderDirectory(FileSpec &file_spec) {
147   FileSpec temp_file("/opt/local/include/lldb");
148   file_spec.SetDirectory(temp_file.GetPath());
149   return true;
150 }
151 
152 bool HostInfoPosix::GetEnvironmentVar(const std::string &var_name,
153                                       std::string &var) {
154   if (const char *pvar = ::getenv(var_name.c_str())) {
155     var = std::string(pvar);
156     return true;
157   }
158   return false;
159 }
160