1 //===-- Procfs.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 "Procfs.h"
10 
11 #include "lldb/Host/linux/Support.h"
12 #include "llvm/Support/MemoryBuffer.h"
13 
14 using namespace lldb;
15 using namespace lldb_private;
16 using namespace process_linux;
17 using namespace llvm;
18 
19 Expected<ArrayRef<uint8_t>> lldb_private::process_linux::GetProcfsCpuInfo() {
20   static Optional<std::vector<uint8_t>> cpu_info;
21   if (!cpu_info) {
22     auto buffer_or_error = errorOrToExpected(getProcFile("cpuinfo"));
23     if (!buffer_or_error)
24       return buffer_or_error.takeError();
25     MemoryBuffer &buffer = **buffer_or_error;
26     cpu_info = std::vector<uint8_t>(
27         reinterpret_cast<const uint8_t *>(buffer.getBufferStart()),
28         reinterpret_cast<const uint8_t *>(buffer.getBufferEnd()));
29   }
30   return *cpu_info;
31 }
32 
33 Expected<std::vector<core_id_t>>
34 lldb_private::process_linux::GetAvailableLogicalCoreIDs(StringRef cpuinfo) {
35   SmallVector<StringRef, 8> lines;
36   cpuinfo.split(lines, "\n", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
37   std::vector<core_id_t> logical_cores;
38 
39   for (StringRef line : lines) {
40     std::pair<StringRef, StringRef> key_value = line.split(':');
41     auto key = key_value.first.trim();
42     auto val = key_value.second.trim();
43     if (key == "processor") {
44       core_id_t processor;
45       if (val.getAsInteger(10, processor))
46         return createStringError(
47             inconvertibleErrorCode(),
48             "Failed parsing the /proc/cpuinfo line entry: %s", line.data());
49       logical_cores.push_back(processor);
50     }
51   }
52   return logical_cores;
53 }
54 
55 llvm::Expected<llvm::ArrayRef<core_id_t>>
56 lldb_private::process_linux::GetAvailableLogicalCoreIDs() {
57   static Optional<std::vector<core_id_t>> logical_cores_ids;
58   if (!logical_cores_ids) {
59     // We find the actual list of core ids by parsing /proc/cpuinfo
60     Expected<ArrayRef<uint8_t>> cpuinfo = GetProcfsCpuInfo();
61     if (!cpuinfo)
62       return cpuinfo.takeError();
63 
64     Expected<std::vector<core_id_t>> core_ids = GetAvailableLogicalCoreIDs(
65         StringRef(reinterpret_cast<const char *>(cpuinfo->data())));
66     if (!core_ids)
67       return core_ids.takeError();
68 
69     logical_cores_ids.emplace(std::move(*core_ids));
70   }
71   return *logical_cores_ids;
72 }
73