[lldb] [Host/{free,net}bsd] Fix process matching by name

[mgorny]

Summary

Fix process matching by name to make 'process attach -n ...' work.

The process finding code has an optimization that defers getting
the process name and executable format after the numeric (PID, UID...)
parameters are tested. However, the ProcessInstanceInfoMatch.Matches()
method has been matching process name against the incomplete process
information as well, and effectively no process ever matched.

In order to fix this, create a copy of ProcessInstanceInfoMatch, set
it to ignore process name and se this copy for the initial match.
The same fix applies to FreeBSD and NetBSD host code.

[labath]

There's a test that this fixes, right?

[emaste]

There is TestProcessAttach.py that has an @expectedFailureNetBSD but no FreeBSD annotation, as well as TestCompletion.py, but I don't see these in the failing list.

process attach -n foo does fail for me on FreeBSD

[mgorny]

In D90454#2364322, @labath wrote:

There's a test that this fixes, right?

The attaching tests still fail for me, I'm trying to investigate why. However, it does fix process attach -n ... in LLDB session.

[labath]

Ok, so it will be tested once the remaining issue is fixed.

[mgorny]

Actually, this is tested already with the old plugin. It's just the new plugin that's suffering the issue, probably inherited from the original NetBSD code :-(.

lldb/source/Host/freebsd/Host.cpp

uint32_t Host::FindProcessesImpl(const ProcessInstanceInfoMatch &match_info,
   kinfos.resize(estimated_pid_count);
   pid_data_size = kinfos.size() * sizeof(struct kinfo_proc);
 
   if (::sysctl(mib, 3, &kinfos[0], &pid_data_size, NULL, 0) != 0)
     return 0;
 
   const size_t actual_pid_count = (pid_data_size / sizeof(struct kinfo_proc));
 
+  ProcessInstanceInfoMatch match_info_noname{match_info};
+  match_info_noname.SetNameMatchType(NameMatch::Ignore);
+
   for (size_t i = 0; i < actual_pid_count; i++) {
     const struct kinfo_proc &kinfo = kinfos[i];
 
     /* Make sure the user is acceptable */
     if (!all_users && kinfo.ki_ruid != our_uid)
       continue;
 
     if (kinfo.ki_pid == our_pid ||  // Skip this process
for (size_t i = 0; i < actual_pid_count; i++) {
     process_info.SetProcessID(kinfo.ki_pid);
     process_info.SetParentProcessID(kinfo.ki_ppid);
     process_info.SetUserID(kinfo.ki_ruid);
     process_info.SetGroupID(kinfo.ki_rgid);
     process_info.SetEffectiveUserID(kinfo.ki_svuid);
     process_info.SetEffectiveGroupID(kinfo.ki_svgid);
 
     // Make sure our info matches before we go fetch the name and cpu type
-    if (match_info.Matches(process_info) &&
+    if (match_info_noname.Matches(process_info) &&
         GetFreeBSDProcessArgs(&match_info, process_info)) {
       GetFreeBSDProcessCPUType(process_info);
       if (match_info.Matches(process_info))
         process_infos.push_back(process_info);
     }
   }
 
   return process_infos.size();

lldb/source/Host/netbsd/HostNetBSD.cpp

uint32_t Host::FindProcessesImpl(const ProcessInstanceInfoMatch &match_info,
   int nproc;
   if ((proc_kinfo = ::kvm_getproc2(kdp, KERN_PROC_ALL, 0,
                                    sizeof(struct ::kinfo_proc2), &nproc)) ==
       NULL) {
     ::kvm_close(kdp);
     return 0;
   }
 
+  ProcessInstanceInfoMatch match_info_noname{match_info};
+  match_info_noname.SetNameMatchType(NameMatch::Ignore);
+
   for (int i = 0; i < nproc; i++) {
     if (proc_kinfo[i].p_pid < 1)
       continue; /* not valid */
     /* Make sure the user is acceptable */
     if (!all_users && proc_kinfo[i].p_ruid != our_uid)
       continue;
 
     if (proc_kinfo[i].p_pid == our_pid ||  // Skip this process
for (int i = 0; i < nproc; i++) {
     ProcessInstanceInfo process_info;
     process_info.SetProcessID(proc_kinfo[i].p_pid);
     process_info.SetParentProcessID(proc_kinfo[i].p_ppid);
     process_info.SetUserID(proc_kinfo[i].p_ruid);
     process_info.SetGroupID(proc_kinfo[i].p_rgid);
     process_info.SetEffectiveUserID(proc_kinfo[i].p_uid);
     process_info.SetEffectiveGroupID(proc_kinfo[i].p_gid);
     // Make sure our info matches before we go fetch the name and cpu type
-    if (match_info.Matches(process_info) &&
+    if (match_info_noname.Matches(process_info) &&
         GetNetBSDProcessArgs(&match_info, process_info)) {
       GetNetBSDProcessCPUType(process_info);
       if (match_info.Matches(process_info))
         process_infos.push_back(process_info);
     }
   }
 
   kvm_close(kdp); /* XXX: we don't check for error here */