labath updated this revision to Diff 62842.
labath added a comment.
run clang-format over the patch
http://reviews.llvm.org/D22039
Files:
source/Plugins/Process/Linux/NativeProcessLinux.cpp
source/Plugins/Process/Linux/NativeProcessLinux.h
Index: source/Plugins/Process/Linux/NativeProcessLinux.h
===================================================================
--- source/Plugins/Process/Linux/NativeProcessLinux.h
+++ source/Plugins/Process/Linux/NativeProcessLinux.h
@@ -202,6 +202,9 @@
::pid_t
Attach(lldb::pid_t pid, Error &error);
+ static void
+ ChildFunc(const LaunchArgs &args) LLVM_ATTRIBUTE_NORETURN;
+
static Error
SetDefaultPtraceOpts(const lldb::pid_t);
Index: source/Plugins/Process/Linux/NativeProcessLinux.cpp
===================================================================
--- source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -130,6 +130,37 @@
return Error("failed to retrieve a valid architecture from the exe module");
}
+// Used to notify the parent about which part of the launch sequence failed.
+enum LaunchCallSpecifier
+{
+ ePtraceFailed,
+ eDupStdinFailed,
+ eDupStdoutFailed,
+ eDupStderrFailed,
+ eChdirFailed,
+ eExecFailed,
+ eSetGidFailed,
+ eSetSigMaskFailed,
+ eLaunchCallMax = eSetSigMaskFailed
+};
+
+static uint8_t LLVM_ATTRIBUTE_NORETURN
+ExitChildAbnormally(LaunchCallSpecifier spec)
+{
+ static_assert(eLaunchCallMax < 0x8, "Have more launch calls than we are able to represent");
+ // This may truncate the topmost bits of the errno because the exit code is only 8 bits wide.
+ // However, it should still give us a pretty good indication of what went wrong. (And the
+ // most common errors have small numbers anyway).
+ _exit(unsigned(spec) | (errno << 3));
+}
+
+// The second member is the errno (or its 5 lowermost bits anyway).
+inline std::pair<LaunchCallSpecifier, uint8_t>
+DecodeChildExitCode(int exit_code)
+{
+ return std::make_pair(LaunchCallSpecifier(exit_code & 0x7), exit_code >> 3);
+}
+
void
DisplayBytes (StreamString &s, void *bytes, uint32_t count)
{
@@ -453,136 +484,119 @@
Attach(pid, error);
}
+void
+NativeProcessLinux::ChildFunc(const LaunchArgs &args)
+{
+ // Start tracing this child that is about to exec.
+ if (ptrace(PTRACE_TRACEME, 0, nullptr, nullptr) == -1)
+ ExitChildAbnormally(ePtraceFailed);
+
+ // Do not inherit setgid powers.
+ if (setgid(getgid()) != 0)
+ ExitChildAbnormally(eSetGidFailed);
+
+ // Attempt to have our own process group.
+ if (setpgid(0, 0) != 0)
+ {
+ // FIXME log that this failed. This is common.
+ // Don't allow this to prevent an inferior exec.
+ }
+
+ // Dup file descriptors if needed.
+ if (args.m_stdin_file_spec)
+ if (!DupDescriptor(args.m_stdin_file_spec, STDIN_FILENO, O_RDONLY))
+ ExitChildAbnormally(eDupStdinFailed);
+
+ if (args.m_stdout_file_spec)
+ if (!DupDescriptor(args.m_stdout_file_spec, STDOUT_FILENO, O_WRONLY | O_CREAT | O_TRUNC))
+ ExitChildAbnormally(eDupStdoutFailed);
+
+ if (args.m_stderr_file_spec)
+ if (!DupDescriptor(args.m_stderr_file_spec, STDERR_FILENO, O_WRONLY | O_CREAT | O_TRUNC))
+ ExitChildAbnormally(eDupStderrFailed);
+
+ // Close everything besides stdin, stdout, and stderr that has no file
+ // action to avoid leaking
+ for (int fd = 3; fd < sysconf(_SC_OPEN_MAX); ++fd)
+ if (!args.m_launch_info.GetFileActionForFD(fd))
+ close(fd);
+
+ // Change working directory
+ if (args.m_working_dir && 0 != ::chdir(args.m_working_dir.GetCString()))
+ ExitChildAbnormally(eChdirFailed);
+
+ // Disable ASLR if requested.
+ if (args.m_launch_info.GetFlags().Test(lldb::eLaunchFlagDisableASLR))
+ {
+ const int old_personality = personality(LLDB_PERSONALITY_GET_CURRENT_SETTINGS);
+ if (old_personality == -1)
+ {
+ // Can't retrieve Linux personality. Cannot disable ASLR.
+ }
+ else
+ {
+ const int new_personality = personality(ADDR_NO_RANDOMIZE | old_personality);
+ if (new_personality == -1)
+ {
+ // Disabling ASLR failed.
+ }
+ else
+ {
+ // Disabling ASLR succeeded.
+ }
+ }
+ }
+
+ // Clear the signal mask to prevent the child from being affected by
+ // any masking done by the parent.
+ sigset_t set;
+ if (sigemptyset(&set) != 0 || pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0)
+ ExitChildAbnormally(eSetSigMaskFailed);
+
+ // Propagate the environment if one is not supplied.
+ const char **envp = args.m_envp;
+ if (envp == NULL || envp[0] == NULL)
+ envp = const_cast<const char **>(environ);
+
+ // Execute. We should never return...
+ execve(args.m_argv[0], const_cast<char *const *>(args.m_argv), const_cast<char *const *>(envp));
+
+ // ...unless exec fails. In which case we definitely need to end the child here.
+ ExitChildAbnormally(eExecFailed);
+}
+
::pid_t
NativeProcessLinux::Launch(LaunchArgs *args, Error &error)
{
assert (args && "null args");
- const char **argv = args->m_argv;
- const char **envp = args->m_envp;
- const FileSpec working_dir = args->m_working_dir;
-
lldb_utility::PseudoTerminal terminal;
const size_t err_len = 1024;
char err_str[err_len];
lldb::pid_t pid;
- // Propagate the environment if one is not supplied.
- if (envp == NULL || envp[0] == NULL)
- envp = const_cast<const char **>(environ);
-
if ((pid = terminal.Fork(err_str, err_len)) == static_cast<lldb::pid_t> (-1))
{
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("Process fork failed: %s", err_str);
return -1;
}
- // Recognized child exit status codes.
- enum {
- ePtraceFailed = 1,
- eDupStdinFailed,
- eDupStdoutFailed,
- eDupStderrFailed,
- eChdirFailed,
- eExecFailed,
- eSetGidFailed,
- eSetSigMaskFailed
- };
-
// Child process.
if (pid == 0)
{
// First, make sure we disable all logging. If we are logging to stdout, our logs can be
// mistaken for inferior output.
Log::DisableAllLogChannels(nullptr);
- // FIXME consider opening a pipe between parent/child and have this forked child
- // send log info to parent re: launch status.
-
- // Start tracing this child that is about to exec.
- error = PtraceWrapper(PTRACE_TRACEME, 0);
- if (error.Fail())
- exit(ePtraceFailed);
// terminal has already dupped the tty descriptors to stdin/out/err.
// This closes original fd from which they were copied (and avoids
// leaking descriptors to the debugged process.
terminal.CloseSlaveFileDescriptor();
- // Do not inherit setgid powers.
- if (setgid(getgid()) != 0)
- exit(eSetGidFailed);
-
- // Attempt to have our own process group.
- if (setpgid(0, 0) != 0)
- {
- // FIXME log that this failed. This is common.
- // Don't allow this to prevent an inferior exec.
- }
-
- // Dup file descriptors if needed.
- if (args->m_stdin_file_spec)
- if (!DupDescriptor(args->m_stdin_file_spec, STDIN_FILENO, O_RDONLY))
- exit(eDupStdinFailed);
-
- if (args->m_stdout_file_spec)
- if (!DupDescriptor(args->m_stdout_file_spec, STDOUT_FILENO, O_WRONLY | O_CREAT | O_TRUNC))
- exit(eDupStdoutFailed);
-
- if (args->m_stderr_file_spec)
- if (!DupDescriptor(args->m_stderr_file_spec, STDERR_FILENO, O_WRONLY | O_CREAT | O_TRUNC))
- exit(eDupStderrFailed);
-
- // Close everything besides stdin, stdout, and stderr that has no file
- // action to avoid leaking
- for (int fd = 3; fd < sysconf(_SC_OPEN_MAX); ++fd)
- if (!args->m_launch_info.GetFileActionForFD(fd))
- close(fd);
-
- // Change working directory
- if (working_dir && 0 != ::chdir(working_dir.GetCString()))
- exit(eChdirFailed);
-
- // Disable ASLR if requested.
- if (args->m_launch_info.GetFlags ().Test (lldb::eLaunchFlagDisableASLR))
- {
- const int old_personality = personality (LLDB_PERSONALITY_GET_CURRENT_SETTINGS);
- if (old_personality == -1)
- {
- // Can't retrieve Linux personality. Cannot disable ASLR.
- }
- else
- {
- const int new_personality = personality (ADDR_NO_RANDOMIZE | old_personality);
- if (new_personality == -1)
- {
- // Disabling ASLR failed.
- }
- else
- {
- // Disabling ASLR succeeded.
- }
- }
- }
-
- // Clear the signal mask to prevent the child from being affected by
- // any masking done by the parent.
- sigset_t set;
- if (sigemptyset(&set) != 0 || pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0)
- exit(eSetSigMaskFailed);
-
- // Execute. We should never return...
- execve(argv[0],
- const_cast<char *const *>(argv),
- const_cast<char *const *>(envp));
-
- // ...unless exec fails. In which case we definitely need to end the child here.
- exit(eExecFailed);
+ ChildFunc(*args);
}
- //
- // This is the parent code here.
- //
Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_PROCESS));
// Wait for the child process to trap on its call to execve.
@@ -603,38 +617,37 @@
}
else if (WIFEXITED(status))
{
- // open, dup or execve likely failed for some reason.
- error.SetErrorToGenericError();
- switch (WEXITSTATUS(status))
+ auto p = DecodeChildExitCode(WEXITSTATUS(status));
+ Error child_error(p.second, eErrorTypePOSIX);
+ const char *failure_reason;
+ switch (p.first)
{
case ePtraceFailed:
- error.SetErrorString("Child ptrace failed.");
+ failure_reason = "Child ptrace failed";
break;
case eDupStdinFailed:
- error.SetErrorString("Child open stdin failed.");
+ failure_reason = "Child open stdin failed";
break;
case eDupStdoutFailed:
- error.SetErrorString("Child open stdout failed.");
+ failure_reason = "Child open stdout failed";
break;
case eDupStderrFailed:
- error.SetErrorString("Child open stderr failed.");
+ failure_reason = "Child open stderr failed";
break;
case eChdirFailed:
- error.SetErrorString("Child failed to set working directory.");
+ failure_reason = "Child failed to set working directory";
break;
case eExecFailed:
- error.SetErrorString("Child exec failed.");
+ failure_reason = "Child exec failed";
break;
case eSetGidFailed:
- error.SetErrorString("Child setgid failed.");
+ failure_reason = "Child setgid failed";
break;
case eSetSigMaskFailed:
- error.SetErrorString("Child failed to set signal mask.");
- break;
- default:
- error.SetErrorString("Child returned unknown exit status.");
+ failure_reason = "Child failed to set signal mask";
break;
}
+ error.SetErrorStringWithFormat("%s: %s", failure_reason, child_error.AsCString());
if (log)
{
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