Files
clang-p2996/lldb/tools/darwin-debug/darwin-debug.cpp
Greg Clayton 6162f9774a Fixed all known race conditions with starting a process in a new terminal.
We now spawn a thread to accept a unix socket connection from the inferior
when it spawns in the terminal, then we launch the process, then we get
the pid back through the unix socket, and then wait for it to SIGSTOP.

darwin-debug now clears the terminal screen and prints out the program and
arguments that are about to be launched.

llvm-svn: 116841
2010-10-19 18:15:50 +00:00

273 lines
8.2 KiB
C++

//===-- Launcher.cpp --------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//----------------------------------------------------------------------
// Darwin launch helper
//
// This program was written to allow programs to be launched in a new
// Terminal.app window and have the application be stopped for debugging
// at the program entry point.
//
// Although it uses posix_spawn(), it uses Darwin specific posix spawn
// attribute flags to accomplish its task. It uses an "exec only" flag
// which avoids forking this process, and it uses a "stop at entry"
// flag to stop the program at the entry point.
//
// Since it uses darwin specific flags this code should not be compiled
// on other systems.
//----------------------------------------------------------------------
#if defined (__APPLE__)
#include <getopt.h>
#include <mach/machine.h>
#include <spawn.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <string>
#ifndef _POSIX_SPAWN_DISABLE_ASLR
#define _POSIX_SPAWN_DISABLE_ASLR 0x0100
#endif
#define streq(a,b) strcmp(a,b) == 0
static struct option g_long_options[] =
{
{ "arch", required_argument, NULL, 'a' },
{ "disable-aslr", no_argument, NULL, 'd' },
{ "no-env", no_argument, NULL, 'e' },
{ "help", no_argument, NULL, 'h' },
{ "setsid", no_argument, NULL, 's' },
{ "unix-socket", required_argument, NULL, 'u' },
{ NULL, 0, NULL, 0 }
};
static void
usage()
{
puts (
"NAME\n"
" darwin-debug -- posix spawn a process that is stopped at the entry point\n"
" for debugging.\n"
"\n"
"SYNOPSIS\n"
" darwin-debug --unix-socket=<SOCKET> [--arch=<ARCH>] [--disable-aslr] [--no-env] [--setsid] [--help] -- <PROGRAM> [<PROGRAM-ARG> <PROGRAM-ARG> ....]\n"
"\n"
"DESCRIPTION\n"
" darwin-debug will exec itself into a child process <PROGRAM> that is\n"
" halted for debugging. It does this by using posix_spawn() along with\n"
" darwin specific posix_spawn flags that allows exec only (no fork), and\n"
" stop at the program entry point. Any program arguments <PROGRAM-ARG> are\n"
" passed on to the exec as the arguments for the new process. The current\n"
" environment will be passed to the new process unless the \"--no-env\"\n"
" option is used. A unix socket must be supplied using the\n"
" --unix-socket=<SOCKET> option so the calling program can handshake with\n"
" this process and get its process id.\n"
"\n"
"EXAMPLE\n"
" darwin-debug --arch=i386 -- /bin/ls -al /tmp\n"
);
exit (1);
}
static void
exit_with_errno (int err, const char *prefix)
{
if (err)
{
fprintf (stderr,
"%s%s",
prefix ? prefix : "",
strerror(err));
exit (err);
}
}
pid_t
posix_spawn_for_debug (char *const *argv, char *const *envp, cpu_type_t cpu_type, int disable_aslr)
{
pid_t pid = 0;
const char *path = argv[0];
posix_spawnattr_t attr;
exit_with_errno (::posix_spawnattr_init (&attr), "::posix_spawnattr_init (&attr) error: ");
// Here we are using a darwin specific feature that allows us to exec only
// since we want this program to turn into the program we want to debug,
// and also have the new program start suspended (right at __dyld_start)
// so we can debug it
short flags = POSIX_SPAWN_START_SUSPENDED | POSIX_SPAWN_SETEXEC;
// Disable ASLR if we were asked to
if (disable_aslr)
flags |= _POSIX_SPAWN_DISABLE_ASLR;
// Set the flags we just made into our posix spawn attributes
exit_with_errno (::posix_spawnattr_setflags (&attr, flags), "::posix_spawnattr_setflags (&attr, flags) error: ");
// Another darwin specific thing here where we can select the architecture
// of the binary we want to re-exec as.
if (cpu_type != 0)
{
size_t ocount = 0;
exit_with_errno (::posix_spawnattr_setbinpref_np (&attr, 1, &cpu_type, &ocount), "posix_spawnattr_setbinpref_np () error: ");
}
exit_with_errno (::posix_spawnp (&pid, path, NULL, &attr, (char * const*)argv, (char * const*)envp), "posix_spawn() error: ");
// This code will only be reached if the posix_spawn exec failed...
::posix_spawnattr_destroy (&attr);
return pid;
}
int main (int argc, char *const *argv, char *const *envp, const char **apple)
{
const char *program_name = strrchr(apple[0], '/');
if (program_name)
program_name++; // Skip the last slash..
else
program_name = apple[0];
#if defined (DEBUG_LLDB_LAUNCHER)
printf("%s called with:\n", program_name);
for (int i=0; i<argc; ++i)
printf("argv[%u] = '%s'\n", i, argv[i]);
#endif
cpu_type_t cpu_type = 0;
bool show_usage = false;
char ch;
int disable_aslr = 0; // By default we disable ASLR
int pass_env = 1;
std::string unix_socket_name;
while ((ch = getopt_long(argc, argv, "a:dehsu:?", g_long_options, NULL)) != -1)
{
switch (ch)
{
case 0:
break;
case 'a': // "-a i386" or "--arch=i386"
if (optarg)
{
if (streq (optarg, "i386"))
cpu_type = CPU_TYPE_I386;
else if (streq (optarg, "x86_64"))
cpu_type = CPU_TYPE_X86_64;
else if (strstr (optarg, "arm") == optarg)
cpu_type = CPU_TYPE_ARM;
else
{
::fprintf (stderr, "error: unsupported cpu type '%s'\n", optarg);
::exit (1);
}
}
break;
case 'd':
disable_aslr = 1;
break;
case 'e':
pass_env = 0;
break;
case 's':
// Create a new session to avoid having control-C presses kill our current
// terminal session when this program is launched from a .command file
::setsid();
break;
case 'u':
unix_socket_name.assign (optarg);
break;
case 'h':
case '?':
default:
show_usage = true;
break;
}
}
argc -= optind;
argv += optind;
if (show_usage || argc <= 0 || unix_socket_name.empty())
usage();
#if defined (DEBUG_LLDB_LAUNCHER)
printf ("\n%s post options:\n", program_name);
for (int i=0; i<argc; ++i)
printf ("argv[%u] = '%s'\n", i, argv[i]);
#endif
// Open the socket that was passed in as an argument
struct sockaddr_un saddr_un;
int s = ::socket (AF_UNIX, SOCK_STREAM, 0);
if (s < 0)
{
perror("error: socket (AF_UNIX, SOCK_STREAM, 0)");
exit(1);
}
saddr_un.sun_family = AF_UNIX;
::strncpy(saddr_un.sun_path, unix_socket_name.c_str(), sizeof(saddr_un.sun_path) - 1);
saddr_un.sun_path[sizeof(saddr_un.sun_path) - 1] = '\0';
saddr_un.sun_len = SUN_LEN (&saddr_un);
if (::connect (s, (struct sockaddr *)&saddr_un, SUN_LEN (&saddr_un)) < 0)
{
perror("error: connect (socket, &saddr_un, saddr_un_len)");
exit(1);
}
// We were able to connect to the socket, now write our PID so whomever
// launched us will know this process's ID
char pid_str[64];
const int pid_str_len = ::snprintf (pid_str, sizeof(pid_str), "%i", ::getpid());
const int bytes_sent = ::send (s, pid_str, pid_str_len, 0);
if (pid_str_len != bytes_sent)
{
perror("error: send (s, pid_str, pid_str_len, 0)");
exit (1);
}
// We are done with the socket
close (s);
system("clear");
printf ("Launching '%s' for debug with %u arguments:\n", argv[0], argc);
for (int i=0; i<argc; ++i)
printf ("argv[%u] = '%s'\n", i, argv[i]);
// Now we posix spawn to exec this process into the inferior that we want
// to debug.
posix_spawn_for_debug (argv,
pass_env ? envp : NULL,
cpu_type,
disable_aslr);
return 0;
}
#endif // #if defined (__APPLE__)