variables.c

android-w.song.android.widget

/* variables.c -- Functions for hacking shell variables. */

/* 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"

#include "bashtypes.h"
#include "posixstat.h"
#include "posixtime.h"

#if defined (__QNX__)
#  if defined (__QNXNTO__)
#    include <sys/netmgr.h>
#  else
#    include <sys/vc.h>
#  endif /* !__QNXNTO__ */
#endif /* __QNX__ */

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

#include <stdio.h>
#include "chartypes.h"
#if defined (HAVE_PWD_H)
#  include <pwd.h>
#endif
#include "bashansi.h"
#include "bashintl.h"

#define NEED_XTRACE_SET_DECL

#include "shell.h"
#include "flags.h"
#include "execute_cmd.h"
#include "findcmd.h"
#include "mailcheck.h"
#include "input.h"
#include "hashcmd.h"
#include "pathexp.h"
#include "alias.h"

#include "builtins/getopt.h"
#include "builtins/common.h"

#if defined (READLINE)
#  include "bashline.h"
#  include <readline/readline.h>
#else
#  include <tilde/tilde.h>
#endif

#if defined (HISTORY)
#  include "bashhist.h"
#  include <readline/history.h>
#endif /* HISTORY */

#if defined (PROGRAMMABLE_COMPLETION)
#  include "pcomplete.h"
#endif

#define TEMPENV_HASH_BUCKETS	4	/* must be power of two */

#define ifsname(s)	((s)[0] == 'I' && (s)[1] == 'F' && (s)[2] == 'S' && (s)[3] == '\0')

extern char **environ;

/* Variables used here and defined in other files. */
extern int posixly_correct;
extern int line_number, line_number_base;
extern int subshell_environment, indirection_level, subshell_level;
extern int build_version, patch_level;
extern int expanding_redir;
extern char *dist_version, *release_status;
extern char *shell_name;
extern char *primary_prompt, *secondary_prompt;
extern char *current_host_name;
extern sh_builtin_func_t *this_shell_builtin;
extern SHELL_VAR *this_shell_function;
extern char *the_printed_command_except_trap;
extern char *this_command_name;
extern char *command_execution_string;
extern time_t shell_start_time;
extern int assigning_in_environment;
extern int executing_builtin;
extern int funcnest_max;

#if defined (READLINE)
extern int no_line_editing;
extern int perform_hostname_completion;
#endif

/* The list of shell variables that the user has created at the global
   scope, or that came from the environment. */
VAR_CONTEXT *global_variables = (VAR_CONTEXT *)NULL;

/* The current list of shell variables, including function scopes */
VAR_CONTEXT *shell_variables = (VAR_CONTEXT *)NULL;

/* The list of shell functions that the user has created, or that came from
   the environment. */
HASH_TABLE *shell_functions = (HASH_TABLE *)NULL;

#if defined (DEBUGGER)
/* The table of shell function definitions that the user defined or that
   came from the environment. */
HASH_TABLE *shell_function_defs = (HASH_TABLE *)NULL;
#endif

/* The current variable context.  This is really a count of how deep into
   executing functions we are. */
int variable_context = 0;

/* The set of shell assignments which are made only in the environment
   for a single command. */
HASH_TABLE *temporary_env = (HASH_TABLE *)NULL;

/* Set to non-zero if an assignment error occurs while putting variables
   into the temporary environment. */
int tempenv_assign_error;

/* Some funky variables which are known about specially.  Here is where
   "$*", "$1", and all the cruft is kept. */
char *dollar_vars[10];
WORD_LIST *rest_of_args = (WORD_LIST *)NULL;

/* The value of $$. */
pid_t dollar_dollar_pid;

/* Non-zero means that we have to remake EXPORT_ENV. */
int array_needs_making = 1;

/* The number of times BASH has been executed.  This is set
   by initialize_variables (). */
int shell_level = 0;

/* An array which is passed to commands as their environment.  It is
   manufactured from the union of the initial environment and the
   shell variables that are marked for export. */
char **export_env = (char **)NULL;
static int export_env_index;
static int export_env_size;

#if defined (READLINE)
static int winsize_assignment;		/* currently assigning to LINES or COLUMNS */
#endif

/* Some forward declarations. */
static void create_variable_tables __P((void));

static void set_machine_vars __P((void));
static void set_home_var __P((void));
static void set_shell_var __P((void));
static char *get_bash_name __P((void));
static void initialize_shell_level __P((void));
static void uidset __P((void));
#if defined (ARRAY_VARS)
static void make_vers_array __P((void));
#endif

static SHELL_VAR *null_assign __P((SHELL_VAR *, char *, arrayind_t, char *));
#if defined (ARRAY_VARS)
static SHELL_VAR *null_array_assign __P((SHELL_VAR *, char *, arrayind_t, char *));
#endif
static SHELL_VAR *get_self __P((SHELL_VAR *));

#if defined (ARRAY_VARS)
static SHELL_VAR *init_dynamic_array_var __P((char *, sh_var_value_func_t *, sh_var_assign_func_t *, int));
static SHELL_VAR *init_dynamic_assoc_var __P((char *, sh_var_value_func_t *, sh_var_assign_func_t *, int));
#endif

static SHELL_VAR *assign_seconds __P((SHELL_VAR *, char *, arrayind_t, char *));
static SHELL_VAR *get_seconds __P((SHELL_VAR *));
static SHELL_VAR *init_seconds_var __P((void));

static int brand __P((void));
static void sbrand __P((unsigned long));		/* set bash random number generator. */
static void seedrand __P((void));			/* seed generator randomly */
static SHELL_VAR *assign_random __P((SHELL_VAR *, char *, arrayind_t, char *));
static SHELL_VAR *get_random __P((SHELL_VAR *));

static SHELL_VAR *assign_lineno __P((SHELL_VAR *, char *, arrayind_t, char *));
static SHELL_VAR *get_lineno __P((SHELL_VAR *));

static SHELL_VAR *assign_subshell __P((SHELL_VAR *, char *, arrayind_t, char *));
static SHELL_VAR *get_subshell __P((SHELL_VAR *));

static SHELL_VAR *get_bashpid __P((SHELL_VAR *));

#if defined (HISTORY)
static SHELL_VAR *get_histcmd __P((SHELL_VAR *));
#endif

#if defined (READLINE)
static SHELL_VAR *get_comp_wordbreaks __P((SHELL_VAR *));
static SHELL_VAR *assign_comp_wordbreaks __P((SHELL_VAR *, char *, arrayind_t, char *));
#endif

#if defined (PUSHD_AND_POPD) && defined (ARRAY_VARS)
static SHELL_VAR *assign_dirstack __P((SHELL_VAR *, char *, arrayind_t, char *));
static SHELL_VAR *get_dirstack __P((SHELL_VAR *));
#endif

#if defined (ARRAY_VARS)
static SHELL_VAR *get_groupset __P((SHELL_VAR *));

static SHELL_VAR *build_hashcmd __P((SHELL_VAR *));
static SHELL_VAR *get_hashcmd __P((SHELL_VAR *));
static SHELL_VAR *assign_hashcmd __P((SHELL_VAR *,  char *, arrayind_t, char *));
#  if defined (ALIAS)
static SHELL_VAR *build_aliasvar __P((SHELL_VAR *));
static SHELL_VAR *get_aliasvar __P((SHELL_VAR *));
static SHELL_VAR *assign_aliasvar __P((SHELL_VAR *,  char *, arrayind_t, char *));
#  endif
#endif

static SHELL_VAR *get_funcname __P((SHELL_VAR *));
static SHELL_VAR *init_funcname_var __P((void));

static void initialize_dynamic_variables __P((void));

static SHELL_VAR *hash_lookup __P((const char *, HASH_TABLE *));
static SHELL_VAR *new_shell_variable __P((const char *));
static SHELL_VAR *make_new_variable __P((const char *, HASH_TABLE *));
static SHELL_VAR *bind_variable_internal __P((const char *, char *, HASH_TABLE *, int, int));

static void dispose_variable_value __P((SHELL_VAR *));
static void free_variable_hash_data __P((PTR_T));

static VARLIST *vlist_alloc __P((int));
static VARLIST *vlist_realloc __P((VARLIST *, int));
static void vlist_add __P((VARLIST *, SHELL_VAR *, int));

static void flatten __P((HASH_TABLE *, sh_var_map_func_t *, VARLIST *, int));

static int qsort_var_comp __P((SHELL_VAR **, SHELL_VAR **));

static SHELL_VAR **vapply __P((sh_var_map_func_t *));
static SHELL_VAR **fapply __P((sh_var_map_func_t *));

static int visible_var __P((SHELL_VAR *));
static int visible_and_exported __P((SHELL_VAR *));
static int export_environment_candidate __P((SHELL_VAR *));
static int local_and_exported __P((SHELL_VAR *));
static int variable_in_context __P((SHELL_VAR *));
#if defined (ARRAY_VARS)
static int visible_array_vars __P((SHELL_VAR *));
#endif

static SHELL_VAR *bind_tempenv_variable __P((const char *, char *));
static void push_temp_var __P((PTR_T));
static void propagate_temp_var __P((PTR_T));
static void dispose_temporary_env __P((sh_free_func_t *));     

static inline char *mk_env_string __P((const char *, const char *));
static char **make_env_array_from_var_list __P((SHELL_VAR **));
static char **make_var_export_array __P((VAR_CONTEXT *));
static char **make_func_export_array __P((void));
static void add_temp_array_to_env __P((char **, int, int));

static int n_shell_variables __P((void));
static int set_context __P((SHELL_VAR *));

static void push_func_var __P((PTR_T));
static void push_exported_var __P((PTR_T));

static inline int find_special_var __P((const char *));

static void
create_variable_tables ()
{
  if (shell_variables == 0)
    {
      shell_variables = global_variables = new_var_context ((char *)NULL, 0);
      shell_variables->scope = 0;
      shell_variables->table = hash_create (0);
    }

  if (shell_functions == 0)
    shell_functions = hash_create (0);

#if defined (DEBUGGER)
  if (shell_function_defs == 0)
    shell_function_defs = hash_create (0);
#endif
}

/* Initialize the shell variables from the current environment.
   If PRIVMODE is nonzero, don't import functions from ENV or
   parse $SHELLOPTS. */
void
initialize_shell_variables (env, privmode)
     char **env;
     int privmode;
{
  char *name, *string, *temp_string;
  int c, char_index, string_index, string_length;
  SHELL_VAR *temp_var;

  create_variable_tables ();

  for (string_index = 0; string = env[string_index++]; )
    {
      char_index = 0;
      name = string;
      while ((c = *string++) && c != '=')
	;
      if (string[-1] == '=')
	char_index = string - name - 1;

      /* If there are weird things in the environment, like `=xxx' or a
	 string without an `=', just skip them. */
      if (char_index == 0)
	continue;

      /* ASSERT(name[char_index] == '=') */
      name[char_index] = '\0';
      /* Now, name = env variable name, string = env variable value, and
	 char_index == strlen (name) */

      temp_var = (SHELL_VAR *)NULL;

      /* If exported function, define it now.  Don't import functions from
	 the environment in privileged mode. */
      if (privmode == 0 && read_but_dont_execute == 0 && STREQN ("() {", string, 4))
	{
	  string_length = strlen (string);
	  temp_string = (char *)xmalloc (3 + string_length + char_index);

	  strcpy (temp_string, name);
	  temp_string[char_index] = ' ';
	  strcpy (temp_string + char_index + 1, string);

	  parse_and_execute (temp_string, name, SEVAL_NONINT|SEVAL_NOHIST);

	  /* Ancient backwards compatibility.  Old versions of bash exported
	     functions like name()=() {...} */
	  if (name[char_index - 1] == ')' && name[char_index - 2] == '(')
	    name[char_index - 2] = '\0';

	  if (temp_var = find_function (name))
	    {
	      VSETATTR (temp_var, (att_exported|att_imported));
	      array_needs_making = 1;
	    }
	  else
	    report_error (_("error importing function definition for `%s'"), name);

	  /* ( */
	  if (name[char_index - 1] == ')' && name[char_index - 2] == '\0')
	    name[char_index - 2] = '(';		/* ) */
	}
#if defined (ARRAY_VARS)
#  if 0
      /* Array variables may not yet be exported. */
      else if (*string == '(' && string[1] == '[' && string[strlen (string) - 1] == ')')
	{
	  string_length = 1;
	  temp_string = extract_array_assignment_list (string, &string_length);
	  temp_var = assign_array_from_string (name, temp_string);
	  FREE (temp_string);
	  VSETATTR (temp_var, (att_exported | att_imported));
	  array_needs_making = 1;
	}
#  endif
#endif
#if 0
      else if (legal_identifier (name))
#else
      else
#endif
	{
	  temp_var = bind_variable (name, string, 0);
	  if (temp_var)
	    {
	      if (legal_identifier (name))
		VSETATTR (temp_var, (att_exported | att_imported));
	      else
		VSETATTR (temp_var, (att_exported | att_imported | att_invisible));
	      array_needs_making = 1;
	    }
	}

      name[char_index] = '=';
      /* temp_var can be NULL if it was an exported function with a syntax
	 error (a different bug, but it still shouldn't dump core). */
      if (temp_var && function_p (temp_var) == 0)	/* XXX not yet */
	{
	  CACHE_IMPORTSTR (temp_var, name);
	}
    }

  set_pwd ();

  /* Set up initial value of $_ */
  temp_var = set_if_not ("_", dollar_vars[0]);

  /* Remember this pid. */
  dollar_dollar_pid = getpid ();

  /* Now make our own defaults in case the vars that we think are
     important are missing. */
  temp_var = set_if_not ("PATH", DEFAULT_PATH_VALUE);
#if 0
  set_auto_export (temp_var);	/* XXX */
#endif

  temp_var = set_if_not ("TERM", "dumb");
#if 0
  set_auto_export (temp_var);	/* XXX */
#endif

#if defined (__QNX__)
  /* set node id -- don't import it from the environment */
  {
    char node_name[22];
#  if defined (__QNXNTO__)
    netmgr_ndtostr(ND2S_LOCAL_STR, ND_LOCAL_NODE, node_name, sizeof(node_name));
#  else
    qnx_nidtostr (getnid (), node_name, sizeof (node_name));
#  endif
    temp_var = bind_variable ("NODE", node_name, 0);
    set_auto_export (temp_var);
  }
#endif

  /* set up the prompts. */
  if (interactive_shell)
    {
#if defined (PROMPT_STRING_DECODE)
      set_if_not ("PS1", primary_prompt);
#else
      if (current_user.uid == -1)
	get_current_user_info ();
      set_if_not ("PS1", current_user.euid == 0 ? "# " : primary_prompt);
#endif
      set_if_not ("PS2", secondary_prompt);
    }
  set_if_not ("PS4", "+ ");

  /* Don't allow IFS to be imported from the environment. */
  temp_var = bind_variable ("IFS", " \t\n", 0);
  setifs (temp_var);

  /* Magic machine types.  Pretty convenient. */
  set_machine_vars ();

  /* Default MAILCHECK for interactive shells.  Defer the creation of a
     default MAILPATH until the startup files are read, because MAIL
     names a mail file if MAILPATH is not set, and we should provide a
     default only if neither is set. */
  if (interactive_shell)
    {
      temp_var = set_if_not ("MAILCHECK", posixly_correct ? "600" : "60");
      VSETATTR (temp_var, att_integer);
    }

  /* Do some things with shell level. */
  initialize_shell_level ();

  set_ppid ();

  /* Initialize the `getopts' stuff. */
  temp_var = bind_variable ("OPTIND", "1", 0);
  VSETATTR (temp_var, att_integer);
  getopts_reset (0);
  bind_variable ("OPTERR", "1", 0);
  sh_opterr = 1;

  if (login_shell == 1 && posixly_correct == 0)
    set_home_var ();

  /* Get the full pathname to THIS shell, and set the BASH variable
     to it. */
  name = get_bash_name ();
  temp_var = bind_variable ("BASH", name, 0);
  free (name);

  /* Make the exported environment variable SHELL be the user's login
     shell.  Note that the `tset' command looks at this variable
     to determine what style of commands to output; if it ends in "csh",
     then C-shell commands are output, else Bourne shell commands. */
  set_shell_var ();

  /* Make a variable called BASH_VERSION which contains the version info. */
  bind_variable ("BASH_VERSION", shell_version_string (), 0);
#if defined (ARRAY_VARS)
  make_vers_array ();
#endif

  if (command_execution_string)
    bind_variable ("BASH_EXECUTION_STRING", command_execution_string, 0);