[Lldb-commits] [lldb] [lldb][windows] allow longer paths than MAX_PATH in GetFileNameByLoadAddress (PR #200225)
Charles Zablit via lldb-commits
lldb-commits at lists.llvm.org
Fri May 29 04:32:44 PDT 2026
https://github.com/charles-zablit updated https://github.com/llvm/llvm-project/pull/200225
>From f0bce07aec8f1681548745a7dee4963a7d146899 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 28 May 2026 18:06:45 +0100
Subject: [PATCH 1/6] [lldb][windows] allow longer paths than MAX_PATH in
GetFileNameByLoadAddress
---
.../Plugins/Process/Windows/Common/DebuggerThread.cpp | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
index c4bfa11e9635d..660bd7bd75498 100644
--- a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
@@ -555,11 +555,14 @@ static std::optional<std::string> GetFileNameByLoadAddress(HANDLE hProcess,
}
// Fallback: ask the kernel for the file backing the mapping at this address.
- std::array<wchar_t, MAX_PATH + 1> mapped_filename;
- if (!::GetMappedFileNameW(hProcess, base_addr, mapped_filename.data(),
- mapped_filename.size()))
+ std::vector<wchar_t> mapped_filename(PATHCCH_MAX_CCH);
+ DWORD mapped_len = ::GetMappedFileNameW(
+ hProcess, base_addr, mapped_filename.data(), mapped_filename.size());
+ if (!mapped_len)
return std::nullopt;
- return ConvertNtDevicePathToDosPath(mapped_filename);
+ std::optional<std::string> dos_path = ConvertNtDevicePathToDosPath(
+ llvm::ArrayRef<wchar_t>(mapped_filename.data(), mapped_len + 1));
+ return dos_path;
}
// Resolve the LOAD_DLL_DEBUG_INFO::lpImageName field.
>From 2cd8c0fcc9b4a417b557539b15cdb9612f6f511c Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Thu, 28 May 2026 18:18:34 +0100
Subject: [PATCH 2/6] fixup! [lldb][windows] allow longer paths than MAX_PATH
in GetFileNameByLoadAddress
---
lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp | 1 +
1 file changed, 1 insertion(+)
diff --git a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
index 660bd7bd75498..11e18a09b9d39 100644
--- a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
@@ -32,6 +32,7 @@
#include "llvm/Support/raw_ostream.h"
#include <optional>
+#include <pathcch.h>
#include <psapi.h>
#ifndef STATUS_WX86_BREAKPOINT
>From 8b3a9b3ad6416fff5345979cf6e51439758a1c88 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Fri, 29 May 2026 11:31:16 +0100
Subject: [PATCH 3/6] grow path buffer
---
.../Process/Windows/Common/DebuggerThread.cpp | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
index 11e18a09b9d39..af080ceb1055f 100644
--- a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
@@ -556,11 +556,18 @@ static std::optional<std::string> GetFileNameByLoadAddress(HANDLE hProcess,
}
// Fallback: ask the kernel for the file backing the mapping at this address.
- std::vector<wchar_t> mapped_filename(PATHCCH_MAX_CCH);
- DWORD mapped_len = ::GetMappedFileNameW(
- hProcess, base_addr, mapped_filename.data(), mapped_filename.size());
- if (!mapped_len)
- return std::nullopt;
+ std::vector<wchar_t> mapped_filename(MAX_PATH + 1);
+ DWORD mapped_len = 0;
+ while (true) {
+ mapped_len = ::GetMappedFileNameW(
+ hProcess, base_addr, mapped_filename.data(), mapped_filename.size());
+ if (SUCCESS(mapped_len))
+ break;
+ if (::GetLastError() != ERROR_MORE_DATA ||
+ mapped_filename.size() >= PATHCCH_MAX_CCH)
+ return std::nullopt;
+ mapped_filename.resize(mapped_filename.size() * 2);
+ }
std::optional<std::string> dos_path = ConvertNtDevicePathToDosPath(
llvm::ArrayRef<wchar_t>(mapped_filename.data(), mapped_len + 1));
return dos_path;
>From ead406c0cfd77c02de67a5a62bdadc1a114a0577 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Fri, 29 May 2026 11:39:25 +0100
Subject: [PATCH 4/6] fixup! grow path buffer
---
lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
index af080ceb1055f..a0b2f54cb6995 100644
--- a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
@@ -563,7 +563,7 @@ static std::optional<std::string> GetFileNameByLoadAddress(HANDLE hProcess,
hProcess, base_addr, mapped_filename.data(), mapped_filename.size());
if (SUCCESS(mapped_len))
break;
- if (::GetLastError() != ERROR_MORE_DATA ||
+ if (::GetLastError() != ERROR_INSUFFICIENT_BUFFER ||
mapped_filename.size() >= PATHCCH_MAX_CCH)
return std::nullopt;
mapped_filename.resize(mapped_filename.size() * 2);
>From f10478777a019f73def44142964439a52a8155c6 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Fri, 29 May 2026 11:57:32 +0100
Subject: [PATCH 5/6] fix incorrect check
---
lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
index a0b2f54cb6995..b130acb09b804 100644
--- a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
@@ -561,7 +561,7 @@ static std::optional<std::string> GetFileNameByLoadAddress(HANDLE hProcess,
while (true) {
mapped_len = ::GetMappedFileNameW(
hProcess, base_addr, mapped_filename.data(), mapped_filename.size());
- if (SUCCESS(mapped_len))
+ if (mapped_len > 0)
break;
if (::GetLastError() != ERROR_INSUFFICIENT_BUFFER ||
mapped_filename.size() >= PATHCCH_MAX_CCH)
>From 54a27c5b5ba70f75bd555c9221ddad63848b9f99 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Fri, 29 May 2026 12:32:29 +0100
Subject: [PATCH 6/6] reverse the condition
---
.../Plugins/Process/Windows/Common/DebuggerThread.cpp | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
index b130acb09b804..140a70d5017c4 100644
--- a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp
@@ -558,13 +558,12 @@ static std::optional<std::string> GetFileNameByLoadAddress(HANDLE hProcess,
// Fallback: ask the kernel for the file backing the mapping at this address.
std::vector<wchar_t> mapped_filename(MAX_PATH + 1);
DWORD mapped_len = 0;
- while (true) {
+ while (mapped_filename.size() <= PATHCCH_MAX_CCH) {
mapped_len = ::GetMappedFileNameW(
hProcess, base_addr, mapped_filename.data(), mapped_filename.size());
- if (mapped_len > 0)
+ if (mapped_len < mapped_filename.size())
break;
- if (::GetLastError() != ERROR_INSUFFICIENT_BUFFER ||
- mapped_filename.size() >= PATHCCH_MAX_CCH)
+ if (::GetLastError() != ERROR_INSUFFICIENT_BUFFER)
return std::nullopt;
mapped_filename.resize(mapped_filename.size() * 2);
}
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