[lldb][AIX] get host info for AIX (cont..) #138687

HemangGadhavi · 2025-05-06T13:26:49Z

This PR is in reference to porting LLDB on AIX.

Link to discussions on llvm discourse and github:

https://discourse.llvm.org/t/port-lldb-to-ibm-aix/80640
Extending LLDB to work on AIX #101657
The complete changes for porting are present in this draft PR:
Extending LLDB to work on AIX #102601

Added testcase for GetProgramFileSpec() & FindProcesses()
Added changes to get the host information for AIX (info like FindProcessesImpl() GetProgramFileSpec()),
continue from the PR [lldb][AIX] get host info for AIX #134354
@DavidSpickett @labath @DhruvSrivastavaX

llvmbot · 2025-05-06T13:27:35Z

@llvm/pr-subscribers-lldb

Author: Hemang Gadhavi (HemangGadhavi)

Changes

This PR is in reference to porting LLDB on AIX.

Link to discussions on llvm discourse and github:

https://discourse.llvm.org/t/port-lldb-to-ibm-aix/80640
Extending LLDB to work on AIX #101657
The complete changes for porting are present in this draft PR:
Extending LLDB to work on AIX #102601

Added changes to get the host information for AIX (info like FindProcessesImpl() GetProgramFileSpec()),
continue from the PR [lldb][AIX] get host info for AIX #134354
@DavidSpickett @labath @DhruvSrivastavaX

Full diff: https://github.com/llvm/llvm-project/pull/138687.diff

2 Files Affected:

(modified) lldb/source/Host/aix/Host.cpp (+48-1)
(modified) lldb/source/Host/aix/HostInfoAIX.cpp (+15)

diff --git a/lldb/source/Host/aix/Host.cpp b/lldb/source/Host/aix/Host.cpp
index a812e061ccae2..ead8202cbbdef 100644
--- a/lldb/source/Host/aix/Host.cpp
+++ b/lldb/source/Host/aix/Host.cpp
@@ -13,6 +13,7 @@
 #include "lldb/Utility/ProcessInfo.h"
 #include "lldb/Utility/Status.h"
 #include "llvm/BinaryFormat/XCOFF.h"
+#include <dirent.h>
 #include <sys/proc.h>
 #include <sys/procfs.h>
 
@@ -41,6 +42,14 @@ static ProcessInstanceInfo::timespec convert(pr_timestruc64_t t) {
   return ts;
 }
 
+static bool IsDirNumeric(const char *dname) {
+  for (; *dname; dname++) {
+    if (!isdigit(*dname))
+      return false;
+  }
+  return true;
+}
+
 static bool GetStatusInfo(::pid_t pid, ProcessInstanceInfo &processInfo,
                           ProcessState &State) {
   struct pstatus pstatusData;
@@ -133,7 +142,45 @@ static bool GetProcessAndStatInfo(::pid_t pid,
 
 uint32_t Host::FindProcessesImpl(const ProcessInstanceInfoMatch &match_info,
                                  ProcessInstanceInfoList &process_infos) {
-  return 0;
+  static const char procdir[] = "/proc/";
+
+  DIR *dirproc = opendir(procdir);
+  if (dirproc) {
+    struct dirent *direntry = nullptr;
+    const uid_t our_uid = getuid();
+    const lldb::pid_t our_pid = getpid();
+    bool all_users = match_info.GetMatchAllUsers();
+
+    while ((direntry = readdir(dirproc)) != nullptr) {
+      if (!IsDirNumeric(direntry->d_name))
+        continue;
+
+      lldb::pid_t pid = atoi(direntry->d_name);
+      // Skip this process.
+      if (pid == our_pid)
+        continue;
+
+      ProcessState State;
+      ProcessInstanceInfo process_info;
+      if (!GetProcessAndStatInfo(pid, process_info, State))
+        continue;
+
+      if (State == ProcessState::Zombie ||
+          State == ProcessState::TracedOrStopped)
+        continue;
+
+      // Check for user match if we're not matching all users and not running
+      // as root.
+      if (!all_users && (our_uid != 0) && (process_info.GetUserID() != our_uid))
+        continue;
+
+      if (match_info.Matches(process_info)) {
+        process_infos.push_back(process_info);
+      }
+    }
+    closedir(dirproc);
+  }
+  return process_infos.size();
 }
 
 bool Host::GetProcessInfo(lldb::pid_t pid, ProcessInstanceInfo &process_info) {
diff --git a/lldb/source/Host/aix/HostInfoAIX.cpp b/lldb/source/Host/aix/HostInfoAIX.cpp
index 61b47462dd647..d720f5c52d3b1 100644
--- a/lldb/source/Host/aix/HostInfoAIX.cpp
+++ b/lldb/source/Host/aix/HostInfoAIX.cpp
@@ -7,6 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/aix/HostInfoAIX.h"
+#include "lldb/Host/posix/Support.h"
+#include <sys/procfs.h>
 
 using namespace lldb_private;
 
@@ -18,5 +20,18 @@ void HostInfoAIX::Terminate() { HostInfoBase::Terminate(); }
 
 FileSpec HostInfoAIX::GetProgramFileSpec() {
   static FileSpec g_program_filespec;
+  struct psinfo psinfoData;
+  auto BufferOrError = getProcFile(getpid(), "psinfo");
+  if (BufferOrError) {
+    std::unique_ptr<llvm::MemoryBuffer> PsinfoBuffer =
+        std::move(*BufferOrError);
+    memcpy(&psinfoData, PsinfoBuffer->getBufferStart(), sizeof(psinfoData));
+    llvm::StringRef exe_path(
+        psinfoData.pr_psargs,
+        strnlen(psinfoData.pr_psargs, sizeof(psinfoData.pr_psargs)));
+    if (!exe_path.empty()) {
+      g_program_filespec.SetFile(exe_path, FileSpec::Style::native);
+    }
+  }
   return g_program_filespec;
 }

labath

Could you also make unit tests for these two functions:

call GetProgramFileSpec and make sure the result is reasonable (exists?)
create a Process and make sure FindProcesses finds it (you can use this trick to re-execute yourself)

lldb/source/Host/aix/Host.cpp

lldb/source/Host/aix/HostInfoAIX.cpp

HemangGadhavi · 2025-05-21T09:35:54Z

Could you also make unit tests for these two functions:

call GetProgramFileSpec and make sure the result is reasonable (exists?)

create a Process and make sure FindProcesses finds it (you can use this trick to re-execute yourself)

Hi @labath
Created the testcases for the GetProgramFileSpec & FindProcesses.

But for the FindProcesses() testcase, we are able to launch the process but later point we are seeing dump on the testcase.
Could you please verify are we giving the input correctly or missing something?
from the logs we can see that GetProcessAndStatInfo() (which is invoked from GetProcessInfo() & FindProcesses()) dumping the core specifically while calling GetExePathAndArch() function on linux.
Could you please help to guide on that.?

lldb/unittests/Host/HostInfoTest.cpp

lldb/unittests/Host/HostTest.cpp

labath · 2025-05-21T13:51:39Z

Could you also make unit tests for these two functions:

call GetProgramFileSpec and make sure the result is reasonable (exists?)

create a Process and make sure FindProcesses finds it (you can use this trick to re-execute yourself)

Hi @labath Created the testcases for the GetProgramFileSpec & FindProcesses.

But for the FindProcesses() testcase, we are able to launch the process but later point we are seeing dump on the testcase. Could you please verify are we giving the input correctly or missing something? from the logs we can see that GetProcessAndStatInfo() (which is invoked from GetProcessInfo() & FindProcesses()) dumping the core specifically while calling GetExePathAndArch() function on linux. Could you please help to guide on that.?

I'll take a look. I don't know if this is the source of the problem, but one thing I noticed is that you're missing some sort of synchronization to make sure the child process doesn't exit before you're able to observe it. A slightly lame but probably sufficient method to do that would be to put a long (say, 1 minute, it's there just to ensure the process exits if something goes wrong) sleep into the child, and then have the parent kill it when it is done with it.

labath · 2025-05-21T14:08:05Z

The failure is in lldb_private::HostInfoBase::GetArchitecture. To fix this, you need to Initialize() the HostInfo class.

HemangGadhavi · 2025-05-22T11:50:56Z

The failure is in lldb_private::HostInfoBase::GetArchitecture. To fix this, you need to Initialize() the HostInfo class.

Thank you @labath. Thanks for the guidance, it worked.
Could you please review and give your comments.

labath · 2025-05-23T07:23:00Z

I don't know if this is the source of the problem, but one thing I noticed is that you're missing some sort of synchronization to make sure the child process doesn't exit before you're able to observe it. A slightly lame but probably sufficient method to do that would be to put a long (say, 1 minute, it's there just to ensure the process exits if something goes wrong) sleep into the child, and then have the parent kill it when it is done with it.

The code looks good, but you still need to do something to ensure there's no race in retrieving the process info.

HemangGadhavi · 2025-05-23T12:05:58Z

I don't know if this is the source of the problem, but one thing I noticed is that you're missing some sort of synchronization to make sure the child process doesn't exit before you're able to observe it. A slightly lame but probably sufficient method to do that would be to put a long (say, 1 minute, it's there just to ensure the process exits if something goes wrong) sleep into the child, and then have the parent kill it when it is done with it.

The code looks good, but you still need to do something to ensure there's no race in retrieving the process info.

Hi @labath Added some delay which gives some time before retrieving the process info.
Please review once.

DhruvSrivastavaX · 2025-05-23T13:39:45Z

Side-Note: @HemangGadhavi Please verify that these pass on our AIX setup as well.

[lldb][AIX] get host info for AIX (cont..)

a47e464

HemangGadhavi requested a review from JDevlieghere as a code owner May 6, 2025 13:26

llvmbot added the lldb label May 6, 2025

labath reviewed May 7, 2025

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Merge branch 'main' into aix_getHostInfo2

69a7aad

HemangGadhavi requested a review from labath May 21, 2025 09:36

labath reviewed May 21, 2025

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Added testcase for GetProgramFileSpec & FindProcesses

adf7708

HemangGadhavi force-pushed the aix_getHostInfo2 branch from f5a0778 to adf7708 Compare May 22, 2025 11:45

HemangGadhavi requested a review from labath May 22, 2025 11:52

Merge branch 'main' into aix_getHostInfo2

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