1 //===-- TildeExpressionResolver.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/Utility/TildeExpressionResolver.h"
10 
11 #include <cassert>
12 #include <system_error>
13 
14 #include "llvm/ADT/STLExtras.h"
15 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/Support/FileSystem.h"
17 #include "llvm/Support/Path.h"
18 #include "llvm/Support/raw_ostream.h"
19 
20 #if !defined(_WIN32)
21 #include <pwd.h>
22 #endif
23 
24 using namespace lldb_private;
25 using namespace llvm;
26 
27 namespace fs = llvm::sys::fs;
28 namespace path = llvm::sys::path;
29 
30 TildeExpressionResolver::~TildeExpressionResolver() = default;
31 
32 bool StandardTildeExpressionResolver::ResolveExact(
33     StringRef Expr, SmallVectorImpl<char> &Output) {
34   // We expect the tilde expression to be ONLY the expression itself, and
35   // contain no separators.
36   assert(!llvm::any_of(Expr, [](char c) { return path::is_separator(c); }));
37   assert(Expr.empty() || Expr[0] == '~');
38 
39   return !fs::real_path(Expr, Output, true);
40 }
41 
42 bool StandardTildeExpressionResolver::ResolvePartial(StringRef Expr,
43                                                      StringSet<> &Output) {
44   // We expect the tilde expression to be ONLY the expression itself, and
45   // contain no separators.
46   assert(!llvm::any_of(Expr, [](char c) { return path::is_separator(c); }));
47   assert(Expr.empty() || Expr[0] == '~');
48 
49   Output.clear();
50 #if defined(_WIN32) || defined(__ANDROID__)
51   return false;
52 #else
53   if (Expr.empty())
54     return false;
55 
56   SmallString<32> Buffer("~");
57   setpwent();
58   struct passwd *user_entry;
59   Expr = Expr.drop_front();
60 
61   while ((user_entry = getpwent()) != nullptr) {
62     StringRef ThisName(user_entry->pw_name);
63     if (!ThisName.starts_with(Expr))
64       continue;
65 
66     Buffer.resize(1);
67     Buffer.append(ThisName);
68     Buffer.append(path::get_separator());
69     Output.insert(Buffer);
70   }
71 
72   return true;
73 #endif
74 }
75 
76 bool TildeExpressionResolver::ResolveFullPath(
77     StringRef Expr, llvm::SmallVectorImpl<char> &Output) {
78   if (!Expr.starts_with("~")) {
79     Output.assign(Expr.begin(), Expr.end());
80     return false;
81   }
82 
83   namespace path = llvm::sys::path;
84   StringRef Left =
85       Expr.take_until([](char c) { return path::is_separator(c); });
86 
87   if (!ResolveExact(Left, Output)) {
88     Output.assign(Expr.begin(), Expr.end());
89     return false;
90   }
91 
92   Output.append(Expr.begin() + Left.size(), Expr.end());
93   return true;
94 }
95