debuggerd: store commandline instead of process name.

Bug: http://b/180605583
Test: debuggerd_test
Change-Id: I018d399a5460f357766dc1b429f645f78fe88565

debuggerd/client/debuggerd_client.cpp

@@ -96,7 +96,7 @@ static std::string get_wchan_data(pid_t pid) {
 
   if (std::string str = data.str(); !str.empty()) {
     buffer << "\n----- Waiting Channels: pid " << pid << " at " << get_timestamp() << " -----\n"
-           << "Cmd line: " << get_process_name(pid) << "\n";
+           << "Cmd line: " << android::base::Join(get_command_line(pid), " ") << "\n";
     buffer << "\n" << str << "\n";
     buffer << "----- end " << std::to_string(pid) << " -----\n";
     buffer << "\n";

debuggerd/crash_dump.cpp

@@ -450,9 +450,6 @@ int main(int argc, char** argv) {
   //       unwind, do not make this too small. b/62828735
   alarm(30 * android::base::HwTimeoutMultiplier());
 
-  // Get the process name (aka cmdline).
-  std::string process_name = get_process_name(g_target_thread);
-
   // Collect the list of open files.
   OpenFilesList open_files;
   {
@@ -489,7 +486,6 @@ int main(int argc, char** argv) {
       info.pid = target_process;
       info.tid = thread;
       info.uid = getuid();
-      info.process_name = process_name;
       info.thread_name = get_thread_name(thread);
 
       unique_fd attr_fd(openat(target_proc_fd, "attr/current", O_RDONLY | O_CLOEXEC));
@@ -517,6 +513,8 @@ int main(int argc, char** argv) {
         ReadCrashInfo(input_pipe, &siginfo, &info.registers, &process_info);
         info.siginfo = &siginfo;
         info.signo = info.siginfo->si_signo;
+
+        info.command_line = get_command_line(g_target_thread);
       } else {
         info.registers.reset(unwindstack::Regs::RemoteGet(thread));
         if (!info.registers) {

debuggerd/libdebuggerd/backtrace.cpp

@@ -34,6 +34,7 @@
 #include <memory>
 #include <string>
 
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <log/log.h>
 #include <unwindstack/Unwinder.h>
@@ -42,11 +43,12 @@
 #include "libdebuggerd/utility.h"
 #include "util.h"
 
-static void dump_process_header(log_t* log, pid_t pid, const char* process_name) {
+static void dump_process_header(log_t* log, pid_t pid,
+                                const std::vector<std::string>& command_line) {
   _LOG(log, logtype::BACKTRACE, "\n\n----- pid %d at %s -----\n", pid, get_timestamp().c_str());
 
-  if (process_name) {
-    _LOG(log, logtype::BACKTRACE, "Cmd line: %s\n", process_name);
+  if (!command_line.empty()) {
+    _LOG(log, logtype::BACKTRACE, "Cmd line: %s\n", android::base::Join(command_line, " ").c_str());
   }
   _LOG(log, logtype::BACKTRACE, "ABI: '%s'\n", ABI_STRING);
 }
@@ -89,7 +91,7 @@ void dump_backtrace(android::base::unique_fd output_fd, unwindstack::Unwinder* u
     return;
   }
 
-  dump_process_header(&log, target->second.pid, target->second.process_name.c_str());
+  dump_process_header(&log, target->second.pid, target->second.command_line);
 
   dump_backtrace_thread(output_fd.get(), unwinder, target->second);
   for (const auto& [tid, info] : thread_info) {
@@ -107,7 +109,7 @@ void dump_backtrace_header(int output_fd) {
   log.amfd_data = nullptr;
 
   pid_t pid = getpid();
-  dump_process_header(&log, pid, get_process_name(pid).c_str());
+  dump_process_header(&log, pid, get_command_line(pid));
 }
 
 void dump_backtrace_footer(int output_fd) {

debuggerd/libdebuggerd/include/libdebuggerd/types.h

@@ -18,6 +18,7 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include <unwindstack/Regs.h>
 
@@ -32,13 +33,14 @@ struct ThreadInfo {
 
   pid_t pid;
 
-  std::string process_name;
+  std::vector<std::string> command_line;
   std::string selinux_label;
 
   int signo = 0;
   siginfo_t* siginfo = nullptr;
 };
 
+// This struct is written into a pipe from inside the crashing process.
 struct ProcessInfo {
   uintptr_t abort_msg_address = 0;
   uintptr_t fdsan_table_address = 0;

debuggerd/libdebuggerd/test/tombstone_test.cpp

@@ -350,11 +350,11 @@ TEST_F(TombstoneTest, dump_header_info) {
 }
 
 TEST_F(TombstoneTest, dump_thread_info_uid) {
-  dump_thread_info(&log_, ThreadInfo{.uid = 1,
-                                     .tid = 3,
-                                     .thread_name = "some_thread",
-                                     .pid = 2,
-                                     .process_name = "some_process"});
+  std::vector<std::string> cmdline = {"some_process"};
+  dump_thread_info(
+      &log_,
+      ThreadInfo{
+          .uid = 1, .tid = 3, .thread_name = "some_thread", .pid = 2, .command_line = cmdline});
   std::string expected = "pid: 2, tid: 3, name: some_thread  >>> some_process <<<\nuid: 1\n";
   ASSERT_STREQ(expected.c_str(), amfd_data_.c_str());
 }

debuggerd/libdebuggerd/tombstone.cpp

@@ -182,8 +182,13 @@ static void dump_thread_info(log_t* log, const ThreadInfo& thread_info) {
   // Don't try to collect logs from the threads that implement the logging system itself.
   if (thread_info.uid == AID_LOGD) log->should_retrieve_logcat = false;
 
+  const char* process_name = "<unknown>";
+  if (!thread_info.command_line.empty()) {
+    process_name = thread_info.command_line[0].c_str();
+  }
+
   _LOG(log, logtype::HEADER, "pid: %d, tid: %d, name: %s  >>> %s <<<\n", thread_info.pid,
-       thread_info.tid, thread_info.thread_name.c_str(), thread_info.process_name.c_str());
+       thread_info.tid, thread_info.thread_name.c_str(), process_name);
   _LOG(log, logtype::HEADER, "uid: %d\n", thread_info.uid);
   if (thread_info.tagged_addr_ctrl != -1) {
     _LOG(log, logtype::HEADER, "tagged_addr_ctrl: %016lx\n", thread_info.tagged_addr_ctrl);
@@ -567,7 +572,7 @@ void engrave_tombstone_ucontext(int tombstone_fd, int proto_fd, uint64_t abort_m
   log.amfd_data = nullptr;
 
   std::string thread_name = get_thread_name(tid);
-  std::string process_name = get_process_name(pid);
+  std::vector<std::string> command_line = get_command_line(pid);
 
   std::unique_ptr<unwindstack::Regs> regs(
       unwindstack::Regs::CreateFromUcontext(unwindstack::Regs::CurrentArch(), ucontext));
@@ -582,7 +587,7 @@ void engrave_tombstone_ucontext(int tombstone_fd, int proto_fd, uint64_t abort_m
       .tid = tid,
       .thread_name = std::move(thread_name),
       .pid = pid,
-      .process_name = std::move(process_name),
+      .command_line = std::move(command_line),
       .selinux_label = std::move(selinux_label),
       .siginfo = siginfo,
   };

debuggerd/libdebuggerd/tombstone_proto.cpp

@@ -562,7 +562,11 @@ void engrave_tombstone_proto(Tombstone* tombstone, unwindstack::Unwinder* unwind
   result.set_uid(main_thread.uid);
   result.set_selinux_label(main_thread.selinux_label);
 
-  result.set_process_name(main_thread.process_name);
+  auto cmd_line = result.mutable_command_line();
+  for (const auto& arg : main_thread.command_line) {
+    *cmd_line->Add() = arg;
+  }
+
   if (!main_thread.siginfo) {
     async_safe_fatal("siginfo missing");
   }

debuggerd/libdebuggerd/tombstone_proto_to_text.cpp

@@ -26,6 +26,7 @@
 #include <vector>
 
 #include <android-base/stringprintf.h>
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <async_safe/log.h>
 
@@ -71,8 +72,13 @@ static int pointer_width(const Tombstone& tombstone) {
 
 static void print_thread_header(CallbackType callback, const Tombstone& tombstone,
                                 const Thread& thread, bool should_log) {
+  const char* process_name = "<unknown>";
+  if (!tombstone.command_line().empty()) {
+    process_name = tombstone.command_line()[0].c_str();
+    CB(should_log, "Cmdline: %s", android::base::Join(tombstone.command_line(), " ").c_str());
+  }
   CB(should_log, "pid: %d, tid: %d, name: %s  >>> %s <<<", tombstone.pid(), thread.id(),
-     thread.name().c_str(), tombstone.process_name().c_str());
+     thread.name().c_str(), process_name);
   CB(should_log, "uid: %d", tombstone.uid());
   if (thread.tagged_addr_ctrl() != -1) {
     CB(should_log, "tagged_addr_ctrl: %016" PRIx64, thread.tagged_addr_ctrl());

debuggerd/proto/tombstone.proto

@@ -17,7 +17,7 @@ message Tombstone {
   uint32 uid = 7;
   string selinux_label = 8;
 
-  string process_name = 9;
+  repeated string command_line = 9;
 
   // Process uptime in seconds.
   uint32 process_uptime = 20;

debuggerd/util.cpp

@@ -26,10 +26,31 @@
 #include <android-base/strings.h>
 #include "protocol.h"
 
+std::vector<std::string> get_command_line(pid_t pid) {
+  std::vector<std::string> result;
+
+  std::string cmdline;
+  android::base::ReadFileToString(android::base::StringPrintf("/proc/%d/cmdline", pid), &cmdline);
+
+  auto it = cmdline.cbegin();
+  while (it != cmdline.cend()) {
+    // string::iterator is a wrapped type, not a raw char*.
+    auto terminator = std::find(it, cmdline.cend(), '\0');
+    result.emplace_back(it, terminator);
+    it = std::find_if(terminator, cmdline.cend(), [](char c) { return c != '\0'; });
+  }
+  if (result.empty()) {
+    result.emplace_back("<unknown>");
+  }
+
+  return result;
+}
+
 std::string get_process_name(pid_t pid) {
   std::string result = "<unknown>";
   android::base::ReadFileToString(android::base::StringPrintf("/proc/%d/cmdline", pid), &result);
-  return result;
+  // We only want the name, not the whole command line, so truncate at the first NUL.
+  return result.c_str();
 }
 
 std::string get_thread_name(pid_t tid) {

debuggerd/util.h

@@ -17,10 +17,12 @@
 #pragma once
 
 #include <string>
+#include <vector>
 
 #include <sys/cdefs.h>
 #include <sys/types.h>
 
+std::vector<std::string> get_command_line(pid_t pid);
 std::string get_process_name(pid_t pid);
 std::string get_thread_name(pid_t tid);