/* -*- Mode: C; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/* vim: set filetype=c tabstop=2 shiftwidth=2 expandtab: */

/*
 * unixsys.s - Unix shell interface
 *
 * Copyright (c) 1984 Taiichi Yuasa and Masami Hagiya
 * Copyright (c) 1990 Giuseppe Attardi
 * Copyright (c) 2001 Juan Jose Garcia Ripoll
 *
 * See file 'LICENSE' for the copyright details.
 *
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h> /* to see whether we have SIGCHLD */
#if !defined(_MSC_VER)
# include <unistd.h>
#endif
#include <ecl/ecl.h>
#include <ecl/internal.h>
#if defined(ECL_MS_WINDOWS_HOST)
# include <windows.h>
#endif
#ifdef HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif
#include <ecl/ecl-inl.h>

/* Shared libraries do not have direct access to environ on Darwin */
#if defined(__APPLE__)
# include <crt_externs.h>
# define environ (*_NSGetEnviron())
/* Mingw defines 'environ' to be a macro instead of a global variable. */
#elif !defined(environ) && defined(HAVE_ENVIRON)
extern char **environ;
#endif

#if defined(__APPLE__)
#include <TargetConditionals.h> /* for TARGET_OS_IPHONE */
#endif

cl_object
si_system(cl_object cmd_string)
{
#if !defined(HAVE_SYSTEM) || (defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE)
  FElibc_error("si_system not implemented",1);
  @(return ECL_NIL);
#else
  cl_object cmd = si_copy_to_simple_base_string(cmd_string);
  int code = system((const char *)(cmd->base_string.self));
  @(return ecl_make_fixnum(code));
#endif
}

cl_object
si_getenv(cl_object var)
{
  const char *value;

  /* Strings have to be null terminated base strings */
  var = si_copy_to_simple_base_string(var);
  value = getenv((char*)var->base_string.self);
  @(return ((value == NULL)? ECL_NIL : ecl_make_simple_base_string(value,-1)));
}

#if defined(HAVE_SETENV) || defined(HAVE_PUTENV)
cl_object
si_setenv(cl_object var, cl_object value)
{
  const cl_env_ptr the_env = ecl_process_env();
  cl_fixnum ret_val;

  /* Strings have to be null terminated base strings */
  var = si_copy_to_simple_base_string(var);
  if (value == ECL_NIL) {
#ifdef HAVE_SETENV
    /* Remove the variable when setting to nil, so that
     * (si:setenv "foo" nil), then (si:getenv "foo) returns
     * the right thing. */
    unsetenv((char*)var->base_string.self);
#else
#if defined(ECL_MS_WINDOWS_HOST)
    si_setenv(var, cl_core.null_string);
#else
    putenv((char*)var->base_string.self);
#endif
#endif
    ret_val = 0;
  } else {
#ifdef HAVE_SETENV
    value = si_copy_to_simple_base_string(value);
    ret_val = setenv((char*)var->base_string.self,
                     (char*)value->base_string.self, 1);
#else
    value = cl_format(4, ECL_NIL, @"~A=~A", var,
                      value);
    value = si_copy_to_simple_base_string(value);
    putenv((char*)value->base_string.self);
#endif
  }
  if (ret_val == -1)
    CEerror(ECL_T, "SI:SETENV failed: insufficient space in environment.",
            1, ECL_NIL);
  ecl_return1(the_env, value);
}
#endif

cl_object
si_environ(void)
{
  cl_object output = ECL_NIL;
#ifdef HAVE_ENVIRON
  char **p;
  for (p = environ; *p; p++) {
    output = CONS(ecl_make_constant_base_string(*p,-1), output);
  }
  output = cl_nreverse(output);
#else
# if defined(ECL_MS_WINDOWS_HOST)
  LPTCH p;
  for (p = GetEnvironmentStrings(); *p; ) {
    output = CONS(ecl_make_constant_base_string(p,-1), output);
    do { (void)0; } while (*(p++));
  }
  output = cl_nreverse(output);
# endif
#endif /* HAVE_ENVIRON */
  @(return output);
}

cl_object
si_getpid(void)
{
#if defined(NACL)
  FElibc_error("si_getpid not implemented",1);
  @(return ECL_NIL);
#else
  @(return ecl_make_fixnum(getpid()));
#endif
}

cl_object
si_getuid(void)
{
#if defined(ECL_MS_WINDOWS_HOST)
  @(return ecl_make_fixnum(0));
#else
  @(return ecl_make_integer(getuid()));
#endif
}

ecl_def_ct_base_string(fake_in_name, "PIPE-READ-ENDPOINT", 18, static, const);
ecl_def_ct_base_string(fake_out_name, "PIPE-WRITE-ENDPOINT", 19, static, const);

cl_object
si_make_pipe()
{
#if defined(NACL)
  FElibc_error("si_make_pipe not implemented",1);
  @(return ECL_NIL);
#else
  cl_object output;
  int fds[2], ret;
#if defined(ECL_MS_WINDOWS_HOST)
  ret = _pipe(fds, 4096, _O_BINARY);
#else
  ret = pipe(fds);
#endif
  if (ret < 0) {
    FElibc_error("Unable to create pipe", 0);
    output = ECL_NIL;
  } else {
    cl_object in = ecl_make_stream_from_fd(fake_in_name, fds[0], ecl_smm_input, 8,
                                           ECL_STREAM_DEFAULT_FORMAT, ECL_NIL);
    cl_object out = ecl_make_stream_from_fd(fake_out_name, fds[1], ecl_smm_output, 8,
                                            ECL_STREAM_DEFAULT_FORMAT, ECL_NIL);
    output = cl_make_two_way_stream(in, out);
  }
  @(return output);
#endif
}

static cl_object
from_list_to_execve_argument(cl_object l, char ***environp)
{
  cl_object p;
  cl_index j, total_size = 0, nstrings = 0;
  cl_object buffer, buffer_stream;
  char **my_environ;
  for (p = l; !Null(p); p = ECL_CONS_CDR(p)) {
    cl_object s = ECL_CONS_CAR(p);
    total_size += s->base_string.fillp + 1;
    nstrings++;
  }
  buffer = ecl_alloc_adjustable_base_string(total_size + 1);
  my_environ = ecl_alloc((nstrings + 1) * sizeof(char*));
  buffer_stream = si_make_sequence_output_stream(1, buffer);
  for (j = 0, p = l; !Null(p); p = ECL_CONS_CDR(p)) {
    cl_object s = ECL_CONS_CAR(p);
    my_environ[j++] = (char*)buffer->base_string.self + buffer->base_string.fillp;
    si_do_write_sequence(s, buffer_stream, ecl_make_fixnum(0), ECL_NIL);
    ecl_write_char(0, buffer_stream);
  }
  ecl_write_char(0, buffer_stream);
  my_environ[j] = 0;
  if (environp) *environp = my_environ;
  return buffer;
}

cl_object
si_waitpid(cl_object pid, cl_object wait)
{
  cl_object status, code;
#if defined(NACL)
  FElibc_error("si_waitpid not implemented",1);
  @(return ECL_NIL);
#elif defined(ECL_MS_WINDOWS_HOST)
  cl_env_ptr the_env = ecl_process_env();
  HANDLE *hProcess = ecl_foreign_data_pointer_safe(pid);
  DWORD exitcode;
  int ok;
  WaitForSingleObject(*hProcess, Null(wait)? 0 : INFINITE);
  ecl_disable_interrupts_env(the_env);
  ok = GetExitCodeProcess(*hProcess, &exitcode);
  if (!ok) {
    status = @':error';
    code = ECL_NIL;
  } else if (exitcode == STILL_ACTIVE) {
    status = @':running';
    code = ECL_NIL;
  } else {
    status = @':exited';
    code = ecl_make_fixnum((int)exitcode);
    pid->foreign.data = NULL;
    CloseHandle(*hProcess);
  }
  ecl_enable_interrupts_env(the_env);
#else
  int code_int, error;

  if (Null(wait))
    error = waitpid(ecl_to_fix(pid), &code_int, WNOHANG | WUNTRACED | WCONTINUED);
  else
    error = waitpid(ecl_to_fix(pid), &code_int, 0);

  if (error < 0) {
    if (errno == EINTR) {
      status = @':abort';
    } else {
      status = @':error';
    }
    code = ECL_NIL;
    pid = ECL_NIL;
  } else if (error == 0) {
    status = ECL_NIL;
    code = ECL_NIL;
    pid = ECL_NIL;
  } else {
    pid = ecl_make_fixnum(error);
    if (WIFEXITED(code_int)) {
      status = @':exited';
      code = ecl_make_fixnum(WEXITSTATUS(code_int));
    } else if (WIFSIGNALED(code_int)) {
      status = @':signaled';
      code = ecl_make_fixnum(WTERMSIG(code_int));
    } else if (WIFSTOPPED(code_int)) {
      status = @':stopped';
      code = ecl_make_fixnum(WSTOPSIG(code_int));
    } else if (WIFCONTINUED(code_int)) {
      status = @':resumed';
      code = ecl_make_fixnum(SIGCONT);
    } else {
      status = @':running';
      code = ECL_NIL;
    }
  }
#endif
  @(return status code pid);
}

#if !defined(ECL_MS_WINDOWS_HOST)
cl_object
si_killpid(cl_object pid, cl_object signal) {
  int ret = kill(ecl_fixnum(pid), ecl_fixnum(signal));
  return ecl_make_fixnum(ret);
}
#endif

#if defined(ECL_MS_WINDOWS_HOST)
static cl_object
make_windows_handle(HANDLE h)
{
  cl_object foreign = ecl_allocate_foreign_data(@':pointer-void',
                                                sizeof(HANDLE*));
  HANDLE *ph = (HANDLE*)foreign->foreign.data;
  *ph = h;
  return foreign;
}
#endif

#if defined(ECL_MS_WINDOWS_HOST)
HANDLE
ecl_stream_to_HANDLE(cl_object s, bool output)
{
  if (ecl_unlikely(!ECL_ANSI_STREAM_P(s)))
    return INVALID_HANDLE_VALUE;
  switch ((enum ecl_smmode)s->stream.mode) {
#if defined(ECL_WSOCK)
  case ecl_smm_input_wsock:
  case ecl_smm_output_wsock:
  case ecl_smm_io_wsock:
#endif
  case ecl_smm_io_wcon:
    return (HANDLE)IO_FILE_DESCRIPTOR(s);
  default: {
    int stream_descriptor = ecl_stream_to_handle(s, output);
    return (stream_descriptor < 0)?
      INVALID_HANDLE_VALUE:
      (HANDLE)_get_osfhandle(stream_descriptor);
  }
  }
}
#endif

#if defined(ECL_MS_WINDOWS_HOST)
static void
create_descriptor(cl_object stream, cl_object direction,
                  HANDLE *child, int *parent) {
  SECURITY_ATTRIBUTES attr;
  HANDLE current = GetCurrentProcess();
  attr.nLength = sizeof(SECURITY_ATTRIBUTES);
  attr.lpSecurityDescriptor = NULL;
  attr.bInheritHandle = TRUE;

  if (stream == @':stream') {
    /* Creates a pipe that we can write to and the child reads
       from. We duplicate one extreme of the pipe so that the child
       does not inherit it. */
    HANDLE tmp;
    if (direction == @':input') {
      if (CreatePipe(child, &tmp, &attr, 0) == 0)
        return;
      if (DuplicateHandle(current, tmp, current,
                          &tmp, 0, FALSE,
                          DUPLICATE_CLOSE_SOURCE |
                          DUPLICATE_SAME_ACCESS) == 0)
        return;

      *parent = _open_osfhandle((intptr_t)tmp, _O_WRONLY);
    }
    else /* if (direction == @':output') */ {
      if (CreatePipe(&tmp, child, &attr, 0) == 0)
        return;
      if (DuplicateHandle(current, tmp, current,
                          &tmp, 0, FALSE,
                          DUPLICATE_CLOSE_SOURCE |
                          DUPLICATE_SAME_ACCESS) == 0)
        return;

      *parent = _open_osfhandle((intptr_t)tmp, _O_RDONLY);
    }

    if (*parent < 0)
      printf("open_osfhandle failed\n");
  }
  else if (!Null(cl_streamp(stream))) {
    HANDLE stream_handle = ecl_stream_to_HANDLE
      (stream, direction != @':input');
    if (stream_handle == INVALID_HANDLE_VALUE) {
      CEerror(@"Create a new stream.",
              "~S argument to RUN-PROGRAM does not have a file handle:~%~S",
              2, direction, stream);
      create_descriptor(@':stream', direction, child, parent);
      return;
    }
    DuplicateHandle(current, stream_handle,
                    current, child, 0, TRUE,
                    DUPLICATE_SAME_ACCESS);
  }
  else {
    FEerror("Invalid ~S argument to EXT:RUN-PROGRAM.", 1, stream);
  }
}
#else
static void
create_descriptor(cl_object stream, cl_object direction,
                  int *child, int *parent) {
  if (stream == @':stream') {
    int fd[2], ret;
    ret = pipe(fd);
    if (ret != 0) {
      FElibc_error("Unable to create pipe", 0);
    }
    if (direction == @':input') {
      *parent = fd[1];
      *child = fd[0];
    } else {
      *parent = fd[0];
      *child = fd[1];
    }
  }
  else if (!Null(cl_streamp(stream))) {
    *child = ecl_stream_to_handle
      (stream, direction != @':input');
    if (*child >= 0) {
      *child = dup(*child);
    } else {
      CEerror(@"Create a new stream.",
              "~S argument to RUN-PROGRAM does not have a file handle:~%~S",
              2, direction, stream);
      create_descriptor(@':stream', direction, child, parent);
      return;
    }
  }
  else {
    FEerror("Invalid ~S argument to EXT:RUN-PROGRAM.", 1, stream);
  }
}
#endif


cl_object
si_run_program_inner(cl_object command, cl_object argv, cl_object my_environ, cl_object wait)
{
  cl_env_ptr the_env = ecl_process_env();
  int parent_write = 0, parent_read = 0, parent_error = 0;
  cl_object pid, stream_read, exit_status;

#if defined(ECL_MS_WINDOWS_HOST)
  argv = cl_format(4, ECL_NIL,
                   @"~A~{ ~A~}",
                   command, argv);
#else
  argv = CONS(command, argv);
#endif

  pid = si_spawn_subprocess(command, argv, my_environ, @':stream', @':stream', @':output');
  parent_write = ecl_fixnum(ecl_nth_value(the_env, 1));
  parent_read = ecl_fixnum(ecl_nth_value(the_env, 2));
  parent_error = ecl_fixnum(ecl_nth_value(the_env, 3));

  /* descriptor is closed in the stream finalizer */
  stream_read = ecl_make_stream_from_fd(command, parent_read,
                                        ecl_smm_input, 8,
                                        ECL_STREAM_DEFAULT_FORMAT,
                                        @':default');

  if (wait != ECL_NIL) {
    si_waitpid(pid, ECL_T);
    exit_status = ecl_nth_value(the_env, 1);
  } else {
    exit_status = ECL_NIL;
  }

  /* close unused descriptors */
  close(parent_write);
  close(parent_error);

  @(return stream_read exit_status pid)
}

cl_object
si_spawn_subprocess(cl_object command, cl_object argv, cl_object my_environ,
                    cl_object input, cl_object output, cl_object error) {

  int parent_write = 0, parent_read = 0, parent_error = 0;
  cl_object pid;

  /* my_environ is either a list or `:default'. */
  if (!ECL_LISTP(my_environ) && !ecl_eql(my_environ, @':default')) {
    FEerror("Malformed :ENVIRON argument to EXT:RUN-PROGRAM.", 0);
  }
  
#if defined(ECL_MS_WINDOWS_HOST)
  {
    BOOL ok;
    DWORD saved_errno;
    STARTUPINFO st_info;
    PROCESS_INFORMATION pr_info;
    HANDLE child_stdout, child_stdin, child_stderr;
    HANDLE current = GetCurrentProcess();
    cl_object env_buffer;
    char *env = NULL;

    argv = si_string_to_octets(5, argv,
                               @':null-terminate', ECL_T,
                               @':element-type', @'base-char');
    if (ECL_LISTP(my_environ)) {
      env_buffer = from_list_to_execve_argument(my_environ, NULL);
      env = (char*)env_buffer->base_string.self;
    }

    create_descriptor(input,  @':input',  &child_stdin,  &parent_write);
    create_descriptor(output, @':output', &child_stdout, &parent_read);
    if (error == @':output') {
      /* The child inherits a duplicate of its own output handle. */
      DuplicateHandle(current, child_stdout, current,
                      &child_stderr, 0, TRUE,
                      DUPLICATE_SAME_ACCESS);
      /* Same for the parent_read and parent_error. */
      parent_error = dup(parent_read);
    }
    else
      create_descriptor(error, @':output', &child_stderr, &parent_error);

    ZeroMemory(&st_info, sizeof(STARTUPINFO));
    st_info.cb = sizeof(STARTUPINFO);
    st_info.lpTitle = NULL; /* No window title, just exec name */
    st_info.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW; /* Specify std{in,out,err} */
    st_info.wShowWindow = SW_HIDE;
    st_info.hStdInput = child_stdin;
    st_info.hStdOutput = child_stdout;
    st_info.hStdError = child_stderr;
    ZeroMemory(&pr_info, sizeof(PROCESS_INFORMATION));

    /* Command is passed as is from argv. It is responsibility of
       higher level interface to decide, whenever arguments should be
       quoted or left as-is. */
    ok = CreateProcess(NULL, (char*)argv->base_string.self,
                       NULL, NULL, /* lpProcess/ThreadAttributes */
                       TRUE, /* Inherit handles (for files) */
                       0, /* dwCreationFlags */
                       env, /* Inherit environment */
                       NULL, /* Current directory */
                       &st_info, /* Startup info */
                       &pr_info); /* Process info */

    /* Child handles must be closed in the parent process */
    /* otherwise the created pipes are never closed       */
    if (ok) {
      CloseHandle(pr_info.hThread);
      pid = make_windows_handle(pr_info.hProcess);
    } else {
      pid = ECL_NIL;
      saved_errno = GetLastError();
    }

    if (child_stdin) CloseHandle(child_stdin);
    if (child_stdout) CloseHandle(child_stdout);
    if (child_stderr) CloseHandle(child_stderr);

    if (Null(pid)) {
      if (parent_write) close(parent_write);
      if (parent_read) close(parent_read);
      if (parent_error > 0) close(parent_error);
      SetLastError(saved_errno);
      FEwin32_error("Could not spawn subprocess to run ~S.", 1, command);
    }
  }
#elif !defined(NACL) /* All POSIX but NaCL/pNaCL */
  {
    cl_object command_encoded = si_string_to_octets(3, command, @':null-terminate', ECL_T);
    int child_pid;
    int child_stdin, child_stdout, child_stderr;
    int saved_errno;

    create_descriptor(input,  @':input',  &child_stdin,  &parent_write);
    create_descriptor(output, @':output', &child_stdout, &parent_read);
    if (error == @':output') {
      child_stderr = child_stdout;
      parent_error = dup(parent_read);
    } else {
      create_descriptor(error,  @':output', &child_stderr, &parent_error);
    }

    child_pid = fork();
    if (child_pid == 0) {
      /* Child */
      int j;
      cl_object p;
      char **argv_ptr = ecl_alloc((ecl_length(argv) + 1) * sizeof(char*));
      for (p = argv, j = 0; p != ECL_NIL; p = ECL_CONS_CDR(p)) {
        cl_object arg = si_string_to_octets(3, ECL_CONS_CAR(p), @':null-terminate', ECL_T);
        argv_ptr[j++] = (char*)arg->base_string.self;
      }
      argv_ptr[j] = NULL;

      if (parent_write) close(parent_write);
      if (parent_read)  close(parent_read);
      if (parent_error) close(parent_error);

      dup2(child_stdin,  STDIN_FILENO);
      dup2(child_stdout, STDOUT_FILENO);
      dup2(child_stderr, STDERR_FILENO);

      if (ECL_LISTP(my_environ)) {
        char **pstrings;
        from_list_to_execve_argument(my_environ, &pstrings);
#if defined(HAVE_ENVIRON)
        environ = pstrings;
        execvp((char*)command_encoded->base_string.self, argv_ptr);
#else
        execve((char*)command_encoded->base_string.self, argv_ptr, pstrings);
#endif
      } else {
        execvp((char*)command_encoded->base_string.self, argv_ptr);
      }
      /* at this point exec has failed */
      perror("exec");
      _exit(EXIT_FAILURE);
    } else if (child_pid > 0) {
      pid = ecl_make_fixnum(child_pid);
    } else {
      pid = ECL_NIL;
      saved_errno = errno;
    }

    close(child_stdin);
    close(child_stdout);
    if (!(error == @':output')) close(child_stderr);

    if (Null(pid)) {
      if (parent_write) close(parent_write);
      if (parent_read) close(parent_read);
      if (parent_error > 0) close(parent_error);
      errno = saved_errno;
      FElibc_error("Could not spawn subprocess to run ~S.", 1, command);
    }
  }
#else  /* NACL */
  {
    FEerror("ext:run-program not implemented", 0);
    @(return ECL_NIL);
  }
#endif

  @(return pid
    ecl_make_fixnum(parent_write)
    ecl_make_fixnum(parent_read)
    ecl_make_fixnum(parent_error))
}