[LLDB] Add IsCoreDumping to ProcessInstanceInfo

[Jlalond]

This is the first useful patch in the series related to enabling PTRACE_SEIZE for processes Coredumping. In order to make the decision if we want to seize or attach, we need to expose that in processinfo. Which we acquire by reading it from /proc/pid/status

Note that in status it is CoreDumping not Coredumping, so I kept with that, even if I prefer Coredumping

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Jacob Lalonde (Jlalond)

Changes

This is the first useful patch in the series related to enabling PTRACE_SEIZE for processes Coredumping. In order to make the decision if we want to seize or attach, we need to expose that in processinfo.

We currently select a few entries from /proc/pid/status, and I now also extract CoreDumping.

Note that in status it is CoreDumping not Coredumping, so I kept with that, even if I prefer Coredumping

---

Full diff: https://github.com/llvm/llvm-project/pull/138580.diff

3 Files Affected:

• (modified) lldb/include/lldb/Utility/ProcessInfo.h (+6)
• (modified) lldb/source/Host/linux/Host.cpp (+5)
• (modified) lldb/unittests/Host/posix/HostTest.cpp (+3)

diff --git a/lldb/include/lldb/Utility/ProcessInfo.h b/lldb/include/lldb/Utility/ProcessInfo.h
index 78ade4bbb1ee6..24041faad80bf 100644
--- a/lldb/include/lldb/Utility/ProcessInfo.h
+++ b/lldb/include/lldb/Utility/ProcessInfo.h
@@ -247,6 +247,11 @@ class ProcessInstanceInfo : public ProcessInfo {
 
   std::optional<bool> IsZombie() const { return m_zombie; }
 
+  // proc/../status specifies CoreDumping as the field
+  // so we match the case here.
+  void SetIsCoreDumping(bool is_coredumping) { m_coredumping = is_coredumping; }
+  std::optional<bool> IsCoreDumping() const { return m_coredumping; }
+
   void Dump(Stream &s, UserIDResolver &resolver) const;
 
   static void DumpTableHeader(Stream &s, bool show_args, bool verbose);
@@ -266,6 +271,7 @@ class ProcessInstanceInfo : public ProcessInfo {
   struct timespec m_cumulative_system_time;
   std::optional<int8_t> m_priority_value = std::nullopt;
   std::optional<bool> m_zombie = std::nullopt;
+  std::optional<bool> m_coredumping = std::nullopt;
 };
 
 typedef std::vector<ProcessInstanceInfo> ProcessInstanceInfoList;
diff --git a/lldb/source/Host/linux/Host.cpp b/lldb/source/Host/linux/Host.cpp
index 8b475a7ab5003..2e2d4fdd84097 100644
--- a/lldb/source/Host/linux/Host.cpp
+++ b/lldb/source/Host/linux/Host.cpp
@@ -213,6 +213,11 @@ static bool GetStatusInfo(::pid_t Pid, ProcessInstanceInfo &ProcessInfo,
     } else if (Line.consume_front("Tgid:")) {
       Line = Line.ltrim();
       Line.consumeInteger(10, Tgid);
+    } else if (Line.consume_front("CoreDumping:")) {
+      uint32_t coredumping;
+      Line = Line.ltrim();
+      Line.consumeInteger(1, coredumping);
+      ProcessInfo.SetIsCoreDumping(coredumping);
     }
   }
   return true;
diff --git a/lldb/unittests/Host/posix/HostTest.cpp b/lldb/unittests/Host/posix/HostTest.cpp
index 5d50de3524d1e..082edccf4e774 100644
--- a/lldb/unittests/Host/posix/HostTest.cpp
+++ b/lldb/unittests/Host/posix/HostTest.cpp
@@ -115,5 +115,8 @@ TEST_F(HostTest, GetProcessInfoSetsPriority) {
   }
   ASSERT_TRUE(Info.IsZombie().has_value());
   ASSERT_FALSE(Info.IsZombie().value());
+
+  ASSERT_TRUE(Info.IsCoreDumping().has_value());
+  ASSERT_FALSE(Info.IsCoreDumping().value());
 }
 #endif

[DavidSpickett]

This is calling:

    template <typename T> bool consumeInteger(unsigned Radix, T &Result) {

• Radix of 1 means binary?
• Parsing can fail, though now I look above and nothing else checks the return value, sigh...

This is new though, so can you make it check the return value and not set if it's false? The type is optional, so anyone making use of this is handling the "I don't know" state already.

[Jlalond]

Good suggestion, I'll validate the return.

[DavidSpickett]

Once you've checked the return value, this LGTM.