Add unconditional logging to debugserver for launch/attach processes

Debugging app launch/attach failures can be difficult because of
all of the messages logged to the console on a darwin system;
emitting specific messages around critical API calls can make it
easier to narrow the search for the console messages related to
the failure.

<rdar://problem/67220442>

Differential revision: https://reviews.llvm.org/D94357

1 files changed, 32 insertions, 14 deletions

diff --git a/lldb/tools/debugserver/source/debugserver.cpp b/lldb/tools/debugserver/source/debugserver.cpp
index fed24fe..d76f4f0 100644
--- a/lldb/tools/debugserver/source/debugserver.cpp
+++ b/lldb/tools/debugserver/source/debugserver.cpp
@@ -583,29 +583,34 @@ RNBRunLoopMode RNBRunLoopInferiorExecuting(RNBRemote *remote) {
       }
 
       if (set_events & RNBContext::event_proc_thread_exiting) {
+        DNBLog("debugserver's process monitoring thread has exited.");
         mode = eRNBRunLoopModeExit;
       }
 
       if (set_events & RNBContext::event_read_thread_exiting) {
         // Out remote packet receiving thread exited, exit for now.
+        DNBLog(
+            "debugserver's packet communication to lldb has been shut down.");
         if (ctx.HasValidProcessID()) {
+          nub_process_t pid = ctx.ProcessID();
           // TODO: We should add code that will leave the current process
           // in its current state and listen for another connection...
           if (ctx.ProcessStateRunning()) {
             if (ctx.GetDetachOnError()) {
-              DNBLog("debugserver's event read thread is exiting, detaching "
-                     "from the inferior process.");
-              DNBProcessDetach(ctx.ProcessID());
+              DNBLog("debugserver has a valid PID %d, it is still running. "
+                     "detaching from the inferior process.",
+                     pid);
+              DNBProcessDetach(pid);
             } else {
-              DNBLog("debugserver's event read thread is exiting, killing the "
-                     "inferior process.");
-              DNBProcessKill(ctx.ProcessID());
+              DNBLog("debugserver killing the inferior process, pid %d.", pid);
+              DNBProcessKill(pid);
             }
           } else {
             if (ctx.GetDetachOnError()) {
-              DNBLog("debugserver's event read thread is exiting, detaching "
-                     "from the inferior process.");
-              DNBProcessDetach(ctx.ProcessID());
+              DNBLog("debugserver has a valid PID %d but it may no longer "
+                     "be running, detaching from the inferior process.",
+                     pid);
+              DNBProcessDetach(pid);
             }
           }
         }
@@ -1104,21 +1109,30 @@ int main(int argc, char *argv[]) {
       if (optarg && optarg[0]) {
         if (strcasecmp(optarg, "auto") == 0)
           g_launch_flavor = eLaunchFlavorDefault;
-        else if (strcasestr(optarg, "posix") == optarg)
+        else if (strcasestr(optarg, "posix") == optarg) {
+          DNBLog(
+              "[LaunchAttach] launch flavor is posix_spawn via cmdline option");
           g_launch_flavor = eLaunchFlavorPosixSpawn;
-        else if (strcasestr(optarg, "fork") == optarg)
+        } else if (strcasestr(optarg, "fork") == optarg)
           g_launch_flavor = eLaunchFlavorForkExec;
 #ifdef WITH_SPRINGBOARD
-        else if (strcasestr(optarg, "spring") == optarg)
+        else if (strcasestr(optarg, "spring") == optarg) {
+          DNBLog(
+              "[LaunchAttach] launch flavor is SpringBoard via cmdline option");
           g_launch_flavor = eLaunchFlavorSpringBoard;
+        }
 #endif
 #ifdef WITH_BKS
-        else if (strcasestr(optarg, "backboard") == optarg)
+        else if (strcasestr(optarg, "backboard") == optarg) {
+          DNBLog("[LaunchAttach] launch flavor is BKS via cmdline option");
           g_launch_flavor = eLaunchFlavorBKS;
+        }
 #endif
 #ifdef WITH_FBS
-        else if (strcasestr(optarg, "frontboard") == optarg)
+        else if (strcasestr(optarg, "frontboard") == optarg) {
+          DNBLog("[LaunchAttach] launch flavor is FBS via cmdline option");
           g_launch_flavor = eLaunchFlavorFBS;
+        }
 #endif
 
         else {
@@ -1398,6 +1412,7 @@ int main(int argc, char *argv[]) {
         dup2(null, STDOUT_FILENO);
         dup2(null, STDERR_FILENO);
       } else if (g_applist_opt != 0) {
+        DNBLog("debugserver running in --applist mode");
         // List all applications we are able to see
         std::string applist_plist;
         int err = ListApplications(applist_plist, false, false);
@@ -1455,6 +1470,7 @@ int main(int argc, char *argv[]) {
             mode = eRNBRunLoopModeExit;
           } else if (g_applist_opt != 0) {
             // List all applications we are able to see
+            DNBLog("debugserver running in applist mode under lockdown");
             std::string applist_plist;
             if (ListApplications(applist_plist, false, false) == 0) {
               DNBLogDebug("Task list: %s", applist_plist.c_str());
@@ -1631,6 +1647,8 @@ int main(int argc, char *argv[]) {
           const char *proc_name = "<unknown>";
           if (ctx.ArgumentCount() > 0)
             proc_name = ctx.ArgumentAtIndex(0);
+          DNBLog("[LaunchAttach] Successfully launched %s (pid = %d).\n",
+                 proc_name, ctx.ProcessID());
           RNBLogSTDOUT("Got a connection, launched process %s (pid = %d).\n",
                        proc_name, ctx.ProcessID());
         }