Start invoking core2md to implement full system crash reporting

user_collector.cc

Index: user_collector.cc
diff --git a/user_collector.cc b/user_collector.cc
index 918f6910acb9f1af174a2c490913e41982a3e6bd..7af35ce33c10a11859d83bea38eca5ab29c14fb9 100644
--- a/user_collector.cc
+++ b/user_collector.cc
@@ -2,6 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <grp.h>  // For struct group.
+#include <pwd.h>  // For struct passwd.
+#include <sys/types.h>  // For getpwuid_r and getgrnam_r.
+
 #include <string>
 
 #include "base/file_util.h"
@@ -14,9 +18,27 @@
 // instead pipe the core file into a user space process.  See
 // core(5) man page.
 static const char kCorePatternFile[] = "/proc/sys/kernel/core_pattern";
+static const char kCoreToMinidumpConverterPath[] = "/usr/bin/core2md";
+static const char kDefaultUserName[] = "chronos";
+static const char kLeaveCoreFile[] = "/etc/leave_core";
+static const char kSystemCrashPath[] = "/var/spool/crash";
+static const char kUserCrashPath[] = "/home/chronos/user/crash";
+
+// Directory mode of the user crash spool directory.
+static const mode_t kUserCrashPathMode = 0755;
+
+// Directory mode of the system crash spool directory.
+static const mode_t kSystemCrashPathMode = 01755;
+
+static const uid_t kRootOwner = 0;
+static const uid_t kRootGroup = 0;
+
+const char *UserCollector::kUserId = "Uid:\t";
+const char *UserCollector::kGroupId = "Gid:\t";
 
 UserCollector::UserCollector()
-    : core_pattern_file_(kCorePatternFile),
+    : generate_diagnostics_(false),
+      core_pattern_file_(kCorePatternFile),
       count_crash_function_(NULL),
       initialized_(false),
       is_feedback_allowed_function_(NULL),
@@ -27,7 +49,8 @@ void UserCollector::Initialize(
     UserCollector::CountCrashFunction count_crash_function,
     const std::string &our_path,
     UserCollector::IsFeedbackAllowedFunction is_feedback_allowed_function,
-    SystemLogging *logger) {
+    SystemLogging *logger,
+    bool generate_diagnostics) {
   CHECK(count_crash_function != NULL);
   CHECK(is_feedback_allowed_function != NULL);
   CHECK(logger != NULL);
@@ -37,6 +60,7 @@ void UserCollector::Initialize(
   is_feedback_allowed_function_ = is_feedback_allowed_function;
   logger_ = logger;
   initialized_ = true;
+  generate_diagnostics_ = generate_diagnostics;
 }
 
 UserCollector::~UserCollector() {
@@ -44,8 +68,7 @@ UserCollector::~UserCollector() {
 
 std::string UserCollector::GetPattern(bool enabled) const {
   if (enabled) {
-    return StringPrintf("|%s --signal=%%s --pid=%%p --exec=%%e",
-                        our_path_.c_str());
+    return StringPrintf("|%s --signal=%%s --pid=%%p", our_path_.c_str());
   } else {
     return "core";
   }
@@ -65,12 +88,336 @@ bool UserCollector::SetUpInternal(bool enabled) {
   return true;
 }
 
-void UserCollector::HandleCrash(int signal, int pid, const std::string &exec) {
+FilePath UserCollector::GetProcessPath(pid_t pid) {
+  return FilePath(StringPrintf("/proc/%d", pid));
+}
+
+bool UserCollector::GetSymlinkTarget(const FilePath &symlink,
+                                     FilePath *target) {
+  int max_size = 32;
+  scoped_array<char> buffer;
+  while (true) {
+    buffer.reset(new char[max_size + 1]);
+    ssize_t size = readlink(symlink.value().c_str(), buffer.get(), max_size);
+    if (size < 0) {
+      return false;
+    }
+    buffer[size] = 0;
+    if (size == max_size) {
+      // Avoid overflow when doubling.
+      if (max_size * 2 > max_size) {
+        max_size *= 2;
+        continue;
+      } else {
+        return false;
+      }
+    }
+    break;
+  }
+
+  *target = FilePath(buffer.get());
+  return true;
+}
+
+bool UserCollector::GetExecutableBaseNameFromPid(uid_t pid,
+                                                 std::string *base_name) {
+  FilePath target;
+  if (!GetSymlinkTarget(GetProcessPath(pid).Append("exe"), &target))
+    return false;
+  *base_name = target.BaseName().value();
+  return true;
+}
+
+bool UserCollector::GetIdFromStatus(const char *prefix,
+                                    IdKind kind,
+                                    const std::string &status_contents,
+                                    int *id) {
+  // From fs/proc/array.c:task_state(), this file contains:
+  // \nUid:\t<uid>\t<euid>\t<suid>\t<fsuid>\n
+  std::vector<std::string> status_lines;
+  SplitString(status_contents, '\n', &status_lines);
+  std::vector<std::string>::iterator line_iterator;
+  for (line_iterator = status_lines.begin();
+       line_iterator != status_lines.end();
+       ++line_iterator) {
+    if (line_iterator->find(prefix) == 0)
+      break;
+  }
+  if (line_iterator == status_lines.end()) {
+    return false;
+  }
+  std::string id_substring = line_iterator->substr(strlen(prefix),
+                                                   std::string::npos);
+  std::vector<std::string> ids;
+  SplitString(id_substring, '\t', &ids);
+  if (ids.size() != kIdMax || kind < 0 || kind >= kIdMax) {
+    return false;
+  }
+  const char *number = ids[kind].c_str();
+  char *end_number = NULL;
+  *id = strtol(number, &end_number, 10);
+  if (*end_number != '\0')
+    return false;
+  return true;
+}
+
+bool UserCollector::GetUserInfoFromName(const std::string &name,
+                                        uid_t *uid,
+                                        gid_t *gid) {
+  char storage[256];
+  struct passwd passwd_storage;
+  struct passwd *passwd_result = NULL;
+
+  if (getpwnam_r(name.c_str(), &passwd_storage, storage, sizeof(storage),
+                 &passwd_result) != 0 || passwd_result == NULL) {
+    logger_->LogError("Cannot find user named %s", name.c_str());
+    return false;
+  }
+
+  *uid = passwd_result->pw_uid;
+  *gid = passwd_result->pw_gid;
+  return true;
+}
+
+bool UserCollector::CopyOffProcFiles(pid_t pid,
+                                     const FilePath &container_dir) {
+  if (!file_util::CreateDirectory(container_dir)) {
+    logger_->LogInfo("Could not create %s", container_dir.value().c_str());
+    return false;
+  }
+  FilePath process_path = GetProcessPath(pid);
+  if (!file_util::PathExists(process_path)) {
+    logger_->LogWarning("Path %s does not exist",
+                        process_path.value().c_str());
+    return false;
+  }
+  static const char *proc_files[] = {
+    "auxv",
+    "cmdline",
+    "environ",
+    "maps",
+    "status"
+  };
+  for (unsigned i = 0; i < arraysize(proc_files); ++i) {
+    if (!file_util::CopyFile(process_path.Append(proc_files[i]),
+                             container_dir.Append(proc_files[i]))) {
+      logger_->LogWarning("Could not copy %s file", proc_files[i]);
+      return false;
+    }
+  }
+  return true;
+}
+
+FilePath UserCollector::GetCrashDirectoryInfo(
+    uid_t process_euid,
+    uid_t default_user_id,
+    gid_t default_user_group,
+    mode_t *mode,
+    uid_t *directory_owner,
+    gid_t *directory_group) {
+  if (process_euid == default_user_id) {
+    *mode = kUserCrashPathMode;
+    *directory_owner = default_user_id;
+    *directory_group = default_user_group;
+    return FilePath(kUserCrashPath);
+  } else {
+    *mode = kSystemCrashPathMode;
+    *directory_owner = kRootOwner;
+    *directory_group = kRootGroup;
+    return FilePath(kSystemCrashPath);
+  }
+}
+
+bool UserCollector::GetCreatedCrashDirectory(pid_t pid,
+                                             FilePath *crash_file_path) {
+  FilePath process_path = GetProcessPath(pid);
+  std::string status;
+  if (!file_util::ReadFileToString(process_path.Append("status"),
+                                   &status)) {
+    logger_->LogError("Could not read status file");
+    return false;
+  }
+  int process_euid;
+  if (!GetIdFromStatus(kUserId, kIdEffective, status, &process_euid)) {
+    logger_->LogError("Could not find euid in status file");
+    return false;
+  }
+  uid_t default_user_id;
+  gid_t default_user_group;
+  if (!GetUserInfoFromName(kDefaultUserName,
+                           &default_user_id,
+                           &default_user_group)) {
+    logger_->LogError("Could not find default user info");
+    return false;
+  }
+  mode_t directory_mode;
+  uid_t directory_owner;
+  gid_t directory_group;
+  *crash_file_path =
+      GetCrashDirectoryInfo(process_euid,
+                            default_user_id,
+                            default_user_group,
+                            &directory_mode,
+                            &directory_owner,
+                            &directory_group);
+
+
+  if (!file_util::PathExists(*crash_file_path)) {
+    // Create the spool directory with the appropriate mode (regardless of
+    // umask) and ownership.
+    mode_t old_mask = umask(0);
+    if (mkdir(crash_file_path->value().c_str(), directory_mode) < 0 ||
+        chown(crash_file_path->value().c_str(),
+              directory_owner,
+              directory_group) < 0) {
+      logger_->LogError("Unable to create appropriate crash directory");
+      return false;
+    }
+    umask(old_mask);
+  }
+
+  if (!file_util::PathExists(*crash_file_path)) {
+    logger_->LogError("Unable to create crash directory %s",
+                      crash_file_path->value().c_str());
+    return false;
+  }
+
+
+  return true;
+}
+
+std::string UserCollector::FormatDumpBasename(const std::string &exec_name,
+                                              time_t timestamp,
+                                              pid_t pid) {
+  struct tm tm;
+  localtime_r(&timestamp, &tm);
+  return StringPrintf("%s.%04d%02d%02d.%02d%02d%02d.%d",
+                      exec_name.c_str(),
+                      tm.tm_year + 1900,
+                      tm.tm_mon + 1,
+                      tm.tm_mday,
+                      tm.tm_hour,
+                      tm.tm_min,
+                      tm.tm_sec,
+                      pid);
+}
+
+bool UserCollector::CopyStdinToCoreFile(const FilePath &core_path) {
+  // Copy off all stdin to a core file.
+  FilePath stdin_path("/dev/fd/0");
+  if (file_util::CopyFile(stdin_path, core_path)) {
+    return true;
+  }
+
+  logger_->LogError("Could not write core file");
+  // If the file system was full, make sure we remove any remnants.
+  file_util::Delete(core_path, false);
+  return false;
+}
+
+bool UserCollector::ConvertCoreToMinidump(const FilePath &core_path,
+                                          const FilePath &procfs_directory,
+                                          const FilePath &minidump_path,
+                                          const FilePath &temp_directory) {
+  // TODO(kmixter): Rewrite to use process_util once it's included in
+  // libchrome.
+  FilePath output_path = temp_directory.Append("output");
+  std::string core2md_command =
+      StringPrintf("\"%s\" \"%s\" \"%s\" \"%s\" > \"%s\" 2>&1",
+                   kCoreToMinidumpConverterPath,
+                   core_path.value().c_str(),
+                   procfs_directory.value().c_str(),
+                   minidump_path.value().c_str(),
+                   output_path.value().c_str());
+  int errorlevel = system(core2md_command.c_str());
+
+  std::string output;
+  file_util::ReadFileToString(output_path, &output);
+  if (errorlevel != 0) {
+    logger_->LogInfo("Problem during %s [result=%d]: %s",
+                     core2md_command.c_str(),
+                     errorlevel,
+                     output.c_str());
+    return false;
+  }
+
+  if (!file_util::PathExists(minidump_path)) {
+    logger_->LogError("Minidump file %s was not created",
+                      minidump_path.value().c_str());
+    return false;
+  }
+  return true;
+}
+
+bool UserCollector::GenerateDiagnostics(pid_t pid,
+                                        const std::string &exec_name) {
+  FilePath container_dir("/tmp");
+  container_dir = container_dir.Append(
+      StringPrintf("crash_reporter.%d", pid));
+
+  if (!CopyOffProcFiles(pid, container_dir)) {
+    file_util::Delete(container_dir, true);
+    return false;
+  }
+
+  FilePath spool_path;
+  if (!GetCreatedCrashDirectory(pid, &spool_path)) {
+    file_util::Delete(container_dir, true);
+    return false;
+  }
+  std::string dump_basename = FormatDumpBasename(exec_name, time(NULL), pid);
+  FilePath core_path = spool_path.Append(
+      StringPrintf("%s.core", dump_basename.c_str()));
+
+  if (!CopyStdinToCoreFile(core_path)) {
+    file_util::Delete(container_dir, true);
+    return false;
+  }
+
+  FilePath minidump_path = spool_path.Append(
+      StringPrintf("%s.dmp", dump_basename.c_str()));
+
+  bool conversion_result = true;
+  if (!ConvertCoreToMinidump(core_path,
+                             container_dir,  // procfs directory
+                             minidump_path,
+                             container_dir)) {  // temporary directory
+    // Note we leave the container directory for inspection.
+    conversion_result = false;
+  }
+
+  if (conversion_result) {
+    logger_->LogInfo("Stored minidump to %s", minidump_path.value().c_str());
+  }
+
+  if (!file_util::PathExists(FilePath(kLeaveCoreFile))) {
+    file_util::Delete(core_path, false);
+  } else {
+    logger_->LogInfo("Leaving core file at %s", core_path.value().c_str());
+  }
+
+  return conversion_result;
+}
+
+bool UserCollector::HandleCrash(int signal, int pid, const char *force_exec) {
   CHECK(initialized_);
+  std::string exec;
+  if (force_exec) {
+    exec.assign(force_exec);
+  } else if (!GetExecutableBaseNameFromPid(pid, &exec)) {
+    // If for some reason we don't have the base name, avoid completely
+    // failing by indicating an unknown name.
+    exec = "unknown";
+  }
   logger_->LogWarning("Received crash notification for %s[%d] sig %d",
                       exec.c_str(), pid, signal);
 
   if (is_feedback_allowed_function_()) {
     count_crash_function_();
   }
+
+  if (generate_diagnostics_) {
+    return GenerateDiagnostics(pid, exec);
+  }
+  return true;
 }