cosmopolitan/third_party/bash/builtins_exec.c

/* exec.c, created from exec.def. */
#line 22 "./exec.def"

#line 43 "./exec.def"

#include "config.h"

#include "bashtypes.h"
#include "posixstat.h"
#include <signal.h>
#include <errno.h>

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#include <stdio.h>

#include "bashansi.h"
#include "bashintl.h"

#include "shell.h"
#include "execute_cmd.h"
#include "findcmd.h"
#if defined (JOB_CONTROL)
#  include "jobs.h"
#endif
#include "flags.h"
#include "trap.h"
#if defined (HISTORY)
#  include "bashhist.h"
#endif
#include "common.h"
#include "bashgetopt.h"
#include "input.h"

/* Not all systems declare ERRNO in errno.h... and some systems #define it! */
#if !defined (errno)
extern int errno;
#endif /* !errno */

extern REDIRECT *redirection_undo_list;
extern char *exec_argv0;

int no_exit_on_failed_exec;

/* If the user wants this to look like a login shell, then
   prepend a `-' onto NAME and return the new name. */
static char *
mkdashname (name)
     char *name;
{
  char *ret;

  ret = (char *)xmalloc (2 + strlen (name));
  ret[0] = '-';
  strcpy (ret + 1, name);
  return ret;
}

int
exec_builtin (list)
     WORD_LIST *list;
{
  int exit_value = EXECUTION_FAILURE;
  int cleanenv, login, opt, orig_job_control;
  char *argv0, *command, **args, **env, *newname, *com2;

  cleanenv = login = orig_job_control = 0;
  exec_argv0 = argv0 = (char *)NULL;

  reset_internal_getopt ();
  while ((opt = internal_getopt (list, "cla:")) != -1)
    {
      switch (opt)
	{
	case 'c':
	  cleanenv = 1;
	  break;
	case 'l':
	  login = 1;
	  break;
	case 'a':
	  argv0 = list_optarg;
	  break;
	CASE_HELPOPT;
	default:
	  builtin_usage ();
	  return (EX_USAGE);
	}
    }
  list = loptend;

  /* First, let the redirections remain. */
  dispose_redirects (redirection_undo_list);
  redirection_undo_list = (REDIRECT *)NULL;

  if (list == 0)
    return (EXECUTION_SUCCESS);

#if defined (RESTRICTED_SHELL)
  if (restricted)
    {
      sh_restricted ((char *)NULL);
      return (EXECUTION_FAILURE);
    }
#endif /* RESTRICTED_SHELL */

  args = strvec_from_word_list (list, 1, 0, (int *)NULL);
  env = (char **)0;

  /* A command with a slash anywhere in its name is not looked up in $PATH. */
  command = absolute_program (args[0]) ? args[0] : search_for_command (args[0], 1);

  if (command == 0)
    {
      if (file_isdir (args[0]))
	{
#if defined (EISDIR)
	  builtin_error (_("%s: cannot execute: %s"), args[0], strerror (EISDIR));
#else
	  builtin_error (_("%s: cannot execute: %s"), args[0], strerror (errno));
#endif
	  exit_value = EX_NOEXEC;
	}
      else
	{
	  sh_notfound (args[0]);
	  exit_value = EX_NOTFOUND;	/* As per Posix.2, 3.14.6 */
	}
      goto failed_exec;
    }

  com2 = full_pathname (command);
  if (com2)
    {
      if (command != args[0])
	free (command);
      command = com2;
    }

  if (argv0)
    {
      free (args[0]);
      args[0] = login ? mkdashname (argv0) : savestring (argv0);
      exec_argv0 = savestring (args[0]);
    }
  else if (login)
    {
      newname = mkdashname (args[0]);
      free (args[0]);
      args[0] = newname;
    }

  /* Decrement SHLVL by 1 so a new shell started here has the same value,
     preserving the appearance.  After we do that, we need to change the
     exported environment to include the new value.  If we've already forked
     and are in a subshell, we don't want to decrement the shell level,
     since we are `increasing' the level */

  if (cleanenv == 0 && (subshell_environment & SUBSHELL_PAREN) == 0)
    adjust_shell_level (-1);

  if (cleanenv)
    {
      env = strvec_create (1);
      env[0] = (char *)0;
    }
  else
    {	
      maybe_make_export_env ();
      env = export_env;
    }

#if defined (HISTORY)
  if (interactive_shell && subshell_environment == 0)
    maybe_save_shell_history ();
#endif /* HISTORY */

  reset_signal_handlers ();		/* leave trap strings in place */

#if defined (JOB_CONTROL)
  orig_job_control = job_control;	/* XXX - was also interactive_shell */
  if (subshell_environment == 0)
    end_job_control ();
  if (interactive || job_control)
    default_tty_job_signals ();		/* undo initialize_job_signals */
#endif /* JOB_CONTROL */

#if defined (BUFFERED_INPUT)
  if (default_buffered_input >= 0)
    sync_buffered_stream (default_buffered_input);
#endif

  exit_value = shell_execve (command, args, env);

  /* We have to set this to NULL because shell_execve has called realloc()
     to stuff more items at the front of the array, which may have caused
     the memory to be freed by realloc().  We don't want to free it twice. */
  args = (char **)NULL;
  if (cleanenv == 0)
    adjust_shell_level (1);

  if (exit_value == EX_NOTFOUND)	/* no duplicate error message */
    goto failed_exec;
  else if (executable_file (command) == 0)
    {
      builtin_error (_("%s: cannot execute: %s"), command, strerror (errno));
      exit_value = EX_NOEXEC;	/* As per Posix.2, 3.14.6 */
    }
  else
    file_error (command);

failed_exec:
  FREE (command);

  if (subshell_environment || (interactive == 0 && no_exit_on_failed_exec == 0))
    exit_shell (last_command_exit_value = exit_value);

  if (args)
    strvec_dispose (args);

  if (env && env != export_env)
    strvec_dispose (env);

  /* If we're not exiting after the exec fails, we restore the shell signal
     handlers and then modify the signal dispositions based on the trap strings
     before the failed exec. */
  initialize_signals (1);
  restore_traps ();

#if defined (JOB_CONTROL)
  if (orig_job_control)
    restart_job_control ();
#endif /* JOB_CONTROL */

  return (exit_value);
}