execute_cmd.c

android-w.song.android.widget

/* execute_cmd.c -- Execute a COMMAND structure. */

/* Copyright (C) 1987-2010 Free Software Foundation, Inc.

   This file is part of GNU Bash, the Bourne Again SHell.

   Bash is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Bash is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "config.h"

#if !defined (__GNUC__) && !defined (HAVE_ALLOCA_H) && defined (_AIX)
  #pragma alloca
#endif /* _AIX && RISC6000 && !__GNUC__ */

#include <stdio.h>
#include "chartypes.h"
#include "bashtypes.h"
#if !defined (_MINIX) && defined (HAVE_SYS_FILE_H)
#  include <sys/file.h>
#endif
#include "filecntl.h"
#include "posixstat.h"
#include <signal.h>
#ifndef _MINIX
#  include <sys/param.h>
#endif

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

#include "posixtime.h"

#if defined (HAVE_SYS_RESOURCE_H) && !defined (RLIMTYPE)
#  include <sys/resource.h>
#endif

#if defined (HAVE_SYS_TIMES_H) && defined (HAVE_TIMES)
#  include <sys/times.h>
#endif

#include <errno.h>

#if !defined (errno)
extern int errno;
#endif

#define NEED_FPURGE_DECL

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

#include "memalloc.h"
#include "shell.h"
#include <y.tab.h>	/* use <...> so we pick it up from the build directory */
#include "flags.h"
#include "builtins.h"
#include "hashlib.h"
#include "jobs.h"
#include "execute_cmd.h"
#include "findcmd.h"
#include "redir.h"
#include "trap.h"
#include "pathexp.h"
#include "hashcmd.h"

#if defined (COND_COMMAND)
#  include "test.h"
#endif

#include "builtins/common.h"
#include "builtins/builtext.h"	/* list of builtins */

#include <glob/strmatch.h>
#include <tilde/tilde.h>

#if defined (BUFFERED_INPUT)
#  include "input.h"
#endif

#if defined (ALIAS)
#  include "alias.h"
#endif

#if defined (HISTORY)
#  include "bashhist.h"
#endif

extern int dollar_dollar_pid;
extern int posixly_correct;
extern int expand_aliases;
extern int autocd;
extern int breaking, continuing, loop_level;
extern int parse_and_execute_level, running_trap, sourcelevel;
extern int command_string_index, line_number;
extern int dot_found_in_search;
extern int already_making_children;
extern int tempenv_assign_error;
extern char *the_printed_command, *shell_name;
extern pid_t last_command_subst_pid;
extern sh_builtin_func_t *last_shell_builtin, *this_shell_builtin;
extern char **subshell_argv, **subshell_envp;
extern int subshell_argc;
extern time_t shell_start_time;
#if 0
extern char *glob_argv_flags;
#endif

extern int close __P((int));

/* Static functions defined and used in this file. */
static void close_pipes __P((int, int));
static void do_piping __P((int, int));
static void bind_lastarg __P((char *));
static int shell_control_structure __P((enum command_type));
static void cleanup_redirects __P((REDIRECT *));

#if defined (JOB_CONTROL)
static int restore_signal_mask __P((sigset_t *));
#endif

static void async_redirect_stdin __P((void));

static int builtin_status __P((int));

static int execute_for_command __P((FOR_COM *));
#if defined (SELECT_COMMAND)
static int displen __P((const char *));
static int print_index_and_element __P((int, int, WORD_LIST *));
static void indent __P((int, int));
static void print_select_list __P((WORD_LIST *, int, int, int));
static char *select_query __P((WORD_LIST *, int, char *, int));
static int execute_select_command __P((SELECT_COM *));
#endif
#if defined (DPAREN_ARITHMETIC)
static int execute_arith_command __P((ARITH_COM *));
#endif
#if defined (COND_COMMAND)
static int execute_cond_node __P((COND_COM *));
static int execute_cond_command __P((COND_COM *));
#endif
#if defined (COMMAND_TIMING)
static int mkfmt __P((char *, int, int, time_t, int));
static void print_formatted_time __P((FILE *, char *,
				      time_t, int, time_t, int,
				      time_t, int, int));
static int time_command __P((COMMAND *, int, int, int, struct fd_bitmap *));
#endif
#if defined (ARITH_FOR_COMMAND)
static intmax_t eval_arith_for_expr __P((WORD_LIST *, int *));
static int execute_arith_for_command __P((ARITH_FOR_COM *));
#endif
static int execute_case_command __P((CASE_COM *));
static int execute_while_command __P((WHILE_COM *));
static int execute_until_command __P((WHILE_COM *));
static int execute_while_or_until __P((WHILE_COM *, int));
static int execute_if_command __P((IF_COM *));
static int execute_null_command __P((REDIRECT *, int, int, int));
static void fix_assignment_words __P((WORD_LIST *));
static int execute_simple_command __P((SIMPLE_COM *, int, int, int, struct fd_bitmap *));
static int execute_builtin __P((sh_builtin_func_t *, WORD_LIST *, int, int));
static int execute_function __P((SHELL_VAR *, WORD_LIST *, int, struct fd_bitmap *, int, int));
static int execute_builtin_or_function __P((WORD_LIST *, sh_builtin_func_t *,
					    SHELL_VAR *,
					    REDIRECT *, struct fd_bitmap *, int));
static void execute_subshell_builtin_or_function __P((WORD_LIST *, REDIRECT *,
						      sh_builtin_func_t *,
						      SHELL_VAR *,
						      int, int, int,
						      struct fd_bitmap *,
						      int));
static int execute_disk_command __P((WORD_LIST *, REDIRECT *, char *,
				      int, int, int, struct fd_bitmap *, int));

static char *getinterp __P((char *, int, int *));
static void initialize_subshell __P((void));
static int execute_in_subshell __P((COMMAND *, int, int, int, struct fd_bitmap *));
#if defined (COPROCESS_SUPPORT)
static int execute_coproc __P((COMMAND *, int, int, struct fd_bitmap *));
#endif

static int execute_pipeline __P((COMMAND *, int, int, int, struct fd_bitmap *));

static int execute_connection __P((COMMAND *, int, int, int, struct fd_bitmap *));

static int execute_intern_function __P((WORD_DESC *, COMMAND *));

/* Set to 1 if fd 0 was the subject of redirection to a subshell.  Global
   so that reader_loop can set it to zero before executing a command. */
int stdin_redir;

/* The name of the command that is currently being executed.
   `test' needs this, for example. */
char *this_command_name;

/* The printed representation of the currently-executing command (same as
   the_printed_command), except when a trap is being executed.  Useful for
   a debugger to know where exactly the program is currently executing. */
char *the_printed_command_except_trap;

/* For catching RETURN in a function. */
int return_catch_flag;
int return_catch_value;
procenv_t return_catch;

/* The value returned by the last synchronous command. */
int last_command_exit_value;

/* Whether or not the last command (corresponding to last_command_exit_value)
   was terminated by a signal, and, if so, which one. */
int last_command_exit_signal;

/* The list of redirections to perform which will undo the redirections
   that I made in the shell. */
REDIRECT *redirection_undo_list = (REDIRECT *)NULL;

/* The list of redirections to perform which will undo the internal
   redirections performed by the `exec' builtin.  These are redirections
   that must be undone even when exec discards redirection_undo_list. */
REDIRECT *exec_redirection_undo_list = (REDIRECT *)NULL;

/* When greater than zero, value is the `level' of builtins we are
   currently executing (e.g. `eval echo a' would have it set to 2). */
int executing_builtin = 0;

/* Non-zero if we are executing a command list (a;b;c, etc.) */
int executing_list = 0;

/* Non-zero if failing commands in a command substitution should not exit the
   shell even if -e is set.  Used to pass the CMD_IGNORE_RETURN flag down to
   commands run in command substitutions by parse_and_execute. */
int comsub_ignore_return = 0;

/* Non-zero if we have just forked and are currently running in a subshell
   environment. */
int subshell_environment;

/* Count of nested subshells, like SHLVL.  Available via $BASH_SUBSHELL */
int subshell_level = 0;

/* Currently-executing shell function. */
SHELL_VAR *this_shell_function;

/* If non-zero, matches in case and [[ ... ]] are case-insensitive */
int match_ignore_case = 0;

int executing_command_builtin = 0;

struct stat SB;		/* used for debugging */

static int special_builtin_failed;

static COMMAND *currently_executing_command;

/* The line number that the currently executing function starts on. */
static int function_line_number;

/* XXX - set to 1 if we're running the DEBUG trap and we want to show the line
   number containing the function name.  Used by executing_line_number to
   report the correct line number.  Kind of a hack. */
static int showing_function_line;

static int line_number_for_err_trap;

/* A sort of function nesting level counter */
int funcnest = 0;
int funcnest_max = 0;		/* XXX - bash-4.2 */

int lastpipe_opt = 0;

struct fd_bitmap *current_fds_to_close = (struct fd_bitmap *)NULL;

#define FD_BITMAP_DEFAULT_SIZE 32

/* Functions to allocate and deallocate the structures used to pass
   information from the shell to its children about file descriptors
   to close. */
struct fd_bitmap *
new_fd_bitmap (size)
     int size;
{
  struct fd_bitmap *ret;

  ret = (struct fd_bitmap *)xmalloc (sizeof (struct fd_bitmap));

  ret->size = size;

  if (size)
    {
      ret->bitmap = (char *)xmalloc (size);
      memset (ret->bitmap, '\0', size);
    }
  else
    ret->bitmap = (char *)NULL;
  return (ret);
}

void
dispose_fd_bitmap (fdbp)
     struct fd_bitmap *fdbp;
{
  FREE (fdbp->bitmap);
  free (fdbp);
}

void
close_fd_bitmap (fdbp)
     struct fd_bitmap *fdbp;
{
  register int i;

  if (fdbp)
    {
      for (i = 0; i < fdbp->size; i++)
	if (fdbp->bitmap[i])
	  {
	    close (i);
	    fdbp->bitmap[i] = 0;
	  }
    }
}

/* Return the line number of the currently executing command. */
int
executing_line_number ()
{
  if (executing && showing_function_line == 0 &&
      (variable_context == 0 || interactive_shell == 0) &&
      currently_executing_command)
    {
#if defined (COND_COMMAND)
      if (currently_executing_command->type == cm_cond)
	return currently_executing_command->value.Cond->line;
#endif
#if defined (DPAREN_ARITHMETIC)
      else if (currently_executing_command->type == cm_arith)
	return currently_executing_command->value.Arith->line;
#endif
#if defined (ARITH_FOR_COMMAND)
      else if (currently_executing_command->type == cm_arith_for)
	return currently_executing_command->value.ArithFor->line;
#endif

	return line_number;
    }
  else
    return line_number;
}

/* Execute the command passed in COMMAND.  COMMAND is exactly what
   read_command () places into GLOBAL_COMMAND.  See "command.h" for the
   details of the command structure.

   EXECUTION_SUCCESS or EXECUTION_FAILURE are the only possible
   return values.  Executing a command with nothing in it returns
   EXECUTION_SUCCESS. */
int
execute_command (command)
     COMMAND *command;
{
  struct fd_bitmap *bitmap;
  int result;

  current_fds_to_close = (struct fd_bitmap *)NULL;
  bitmap = new_fd_bitmap (FD_BITMAP_DEFAULT_SIZE);
  begin_unwind_frame ("execute-command");
  add_unwind_protect (dispose_fd_bitmap, (char *)bitmap);

  /* Just do the command, but not asynchronously. */
  result = execute_command_internal (command, 0, NO_PIPE, NO_PIPE, bitmap);

  dispose_fd_bitmap (bitmap);
  discard_unwind_frame ("execute-command");

#if defined (PROCESS_SUBSTITUTION)
  /* don't unlink fifos if we're in a shell function; wait until the function
     returns. */
  if (variable_context == 0)
    unlink_fifo_list ();
#endif /* PROCESS_SUBSTITUTION */

  QUIT;
  return (result);
}

/* Return 1 if TYPE is a shell control structure type. */
static int
shell_control_structure (type)
     enum command_type type;
{
  switch (type)
    {
#if defined (ARITH_FOR_COMMAND)
    case cm_arith_for:
#endif
#if defined (SELECT_COMMAND)
    case cm_select:
#endif
#if defined (DPAREN_ARITHMETIC)
    case cm_arith:
#endif
#if defined (COND_COMMAND)
    case cm_cond:
#endif
    case cm_case:
    case cm_while:
    case cm_until:
    case cm_if:
    case cm_for:
    case cm_group:
    case cm_function_def:
      return (1);

    default:
      return (0);
    }
}

/* A function to use to unwind_protect the redirection undo list
   for loops. */
static void
cleanup_redirects (list)
     REDIRECT *list;
{
  do_redirections (list, RX_ACTIVE);
  dispose_redirects (list);
}

#if 0
/* Function to unwind_protect the redirections for functions and builtins. */
static void
cleanup_func_redirects (list)
     REDIRECT *list;
{
  do_redirections (list, RX_ACTIVE);
}
#endif

void
dispose_exec_redirects ()
{
  if (exec_redirection_undo_list)
    {
      dispose_redirects (exec_redirection_undo_list);
      exec_redirection_undo_list = (REDIRECT *)NULL;
    }
}

#if defined (JOB_CONTROL)
/* A function to restore the signal mask to its proper value when the shell
   is interrupted or errors occur while creating a pipeline. */
static int
restore_signal_mask (set)
     sigset_t *set;
{
  return (sigprocmask (SIG_SETMASK, set, (sigset_t *)NULL));
}
#endif /* JOB_CONTROL */

#ifdef DEBUG
/* A debugging function that can be called from gdb, for instance. */
void