path: root/builtins/common.c

/* Copyright (C) 1987, 1989, 1991 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 1, 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; see the file COPYING.  If not, write to the Free Software
   Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */

#include <stdio.h>
#include <sys/types.h>
#include "../posixstat.h"
#if defined (HAVE_VFPRINTF)
#include <varargs.h>
#endif /* VFPRINTF */

#if defined (HAVE_STRING_H)
#  include <string.h>
#else /* !HAVE_STRING_H */
#  include <strings.h>
#endif /* !HAVE_STRING_H */

#include "../shell.h"
#include "../unwind_prot.h"
#include "../maxpath.h"
#include "../jobs.h"
#include "../builtins.h"
#include "../input.h"
#include "../execute_cmd.h"
#include "hashcom.h"
#include "common.h"
#include <tilde/tilde.h>

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

extern int no_symbolic_links, interactive, interactive_shell;
extern int indirection_level, startup_state;
extern int last_command_exit_value;
extern int hashing_disabled;
extern int variable_context;
extern char *this_command_name, *shell_name;
extern COMMAND *global_command;
extern HASH_TABLE *hashed_filenames;

/* Read a numeric arg for this_command_name, the name of the shell builtin
   that wants it.  LIST is the word list that the arg is to come from. */
int
get_numeric_arg (list)
     WORD_LIST *list;
{
  int count = 1;

  if (list)
    {
      register char *arg;
      int sign = 1;

      arg = list->word->word;
      if (!arg)
	goto bad_number;

      /* Skip optional leading white space. */
      while (whitespace (*arg))
	arg++;

      if (!*arg)
        goto bad_number;

      /* We allow leading `-' or `+'. */
      if (*arg == '-' || *arg == '+')
	{
	  if (!digit (arg[1]))
	    goto bad_number;

	  if (*arg == '-')
	    sign = -1;

	  arg++;
	}

      for (count = 0; digit (*arg); arg++)
	count = (count * 10) + digit_value (*arg);

      /* Skip trailing whitespace, if any. */
      while (whitespace (*arg))
        arg++;

      if (!*arg)
        count = count * sign;
      else
	{
  bad_number:
	  builtin_error ("bad non-numeric arg `%s'", list->word->word);
	  throw_to_top_level ();
	}
      no_args (list->next);
    }
  return (count);
}

/* This is a lot like report_error (), but it is for shell builtins
   instead of shell control structures, and it won't ever exit the
   shell. */
#if defined (HAVE_VFPRINTF)
void
builtin_error (va_alist)
     va_dcl
{
  char *format;
  va_list args;

  if (this_command_name && *this_command_name)
    fprintf (stderr, "%s: ", this_command_name);

  va_start (args);
  format = va_arg (args, char *);
  vfprintf (stderr, format, args);
  va_end (args);
  fprintf (stderr, "\n");
}
#else /* !HAVE_VFPRINTF */
void
builtin_error (format, arg1, arg2, arg3, arg4, arg5)
     char *format, *arg1, *arg2, *arg3, *arg4, *arg5;
{
  if (this_command_name && *this_command_name)
    fprintf (stderr, "%s: ", this_command_name);

  fprintf (stderr, format, arg1, arg2, arg3, arg4, arg5);
  fprintf (stderr, "\n");
  fflush (stderr);
}
#endif /* !HAVE_VFPRINTF */

/* Remember LIST in $0 ... $9, and REST_OF_ARGS.  If DESTRUCTIVE is
   non-zero, then discard whatever the existing arguments are, else
   only discard the ones that are to be replaced. */
void
remember_args (list, destructive)
     WORD_LIST *list;
     int destructive;
{
  register int i;

  for (i = 1; i < 10; i++)
    {
      if (destructive && dollar_vars[i])
	{
	  free (dollar_vars[i]);
	  dollar_vars[i] = (char *)NULL;
	}

      if (list)
	{
	  if (!destructive && dollar_vars[i])
	    free (dollar_vars[i]);

	  dollar_vars[i] = savestring (list->word->word);
	  list = list->next;
	}
    }

  /* If arguments remain, assign them to REST_OF_ARGS.
     Note that copy_word_list (NULL) returns NULL, and
     that dispose_words (NULL) does nothing. */
  if (destructive || list)
    {
      dispose_words (rest_of_args);
      rest_of_args = copy_word_list (list);
    }

  if (destructive)
    set_dollar_vars_changed ();
}

/* Return if LIST is NULL else barf and jump to top_level. */
void
no_args (list)
     WORD_LIST *list;
{
  if (list)
    {
      builtin_error ("extra arguments");
      longjmp (top_level, DISCARD);
    }
}

/* Return the octal number parsed from STRING, or -1 to indicate
   that the string contained a bad number. */
int
read_octal (string)
     char *string;
{
  int result = 0;
  int digits = 0;

  while (*string && *string >= '0' && *string < '8')
    {
      digits++;
      result = (result * 8) + *string++ - '0';
    }

  if (!digits || result > 0777 || *string)
    result = -1;

  return (result);
}

/* Temporary static. */
static char *dotted_filename = (char *)NULL;

/* Return the full pathname that FILENAME hashes to.  If FILENAME
   is hashed, but data->check_dot is non-zero, check ./FILENAME
   and return that if it is executable. */
char *
find_hashed_filename (filename)
     char *filename;
{
  register BUCKET_CONTENTS *item;

  if (hashing_disabled)
    return ((char *)NULL);

  item = find_hash_item (filename, hashed_filenames);

  if (item)
    {
      /* If this filename is hashed, but `.' comes before it in the path,
	 then see if `./filename' is an executable. */
      if (pathdata(item)->check_dot)
	{
	  if (dotted_filename)
	    free (dotted_filename);

	  dotted_filename = (char *)xmalloc (3 + strlen (filename));
	  strcpy (dotted_filename, "./");
	  strcat (dotted_filename, filename);

	  if (executable_file (dotted_filename))
	    return (dotted_filename);

	  /* Watch out.  If this file was hashed to "./filename", and
	     "./filename" is not executable, then return NULL. */

	  /* Since we already know "./filename" is not executable, what
	     we're really interested in is whether or not the `path'
	     portion of the hashed filename is equivalent to the current
	     directory, but only if it starts with a `.'.  (This catches
	     ./. and so on.)  same_file () is in execute_cmd.c; it tests
	     general Unix file equivalence -- same device and inode. */
	  {
	    char *path = pathdata (item)->path;

	    if (*path == '.')
	      {
		int same = 0;
		char *tail;

		tail = (char *) strrchr (path, '/');

		if (tail)
		  {
		    *tail = '\0';
		    same = same_file
		      (".", path, (struct stat *)NULL, (struct stat *)NULL);
		    *tail = '/';
		  }
		if (same)
		  return ((char *)NULL);
	      }
	  }
	}
      return (pathdata (item)->path);
    }
  else
    return ((char *)NULL);
}

/* Remove FILENAME from the table of hashed commands. */
void
remove_hashed_filename (filename)
     char *filename;
{
  register BUCKET_CONTENTS *item;

  if (hashing_disabled)
    return;

  item = remove_hash_item (filename, hashed_filenames);
  if (item)
    {
      if (item->data)
        {
	  free (pathdata(item)->path);
	  free (item->data);
        }
      if (item->key)
	free (item->key);
      free (item);
    }
}

/* **************************************************************** */
/*								    */
/*		    Pushing and Popping a Context		    */
/*								    */
/* **************************************************************** */

static WORD_LIST **dollar_arg_stack = (WORD_LIST **)NULL;
static int dollar_arg_stack_slots = 0;
static int dollar_arg_stack_index = 0;

void
push_context ()
{
  push_dollar_vars ();
  variable_context++;
}

void
pop_context ()
{
  pop_dollar_vars ();
  kill_all_local_variables ();
  variable_context--;
}

/* Save the existing positional parameters on a stack. */
void
push_dollar_vars ()
{
  if (dollar_arg_stack_index + 2 > dollar_arg_stack_slots)
    {
      dollar_arg_stack = (WORD_LIST **)
	xrealloc (dollar_arg_stack, (dollar_arg_stack_slots += 10)
		  * sizeof (WORD_LIST **));
    }
  dollar_arg_stack[dollar_arg_stack_index] = list_rest_of_args ();
  dollar_arg_stack[++dollar_arg_stack_index] = (WORD_LIST *)NULL;
}

/* Restore the positional parameters from our stack. */
void
pop_dollar_vars ()
{
  if (!dollar_arg_stack || !dollar_arg_stack_index)
    return;

  remember_args (dollar_arg_stack[--dollar_arg_stack_index], 1);
  dispose_words (dollar_arg_stack[dollar_arg_stack_index]);
  dollar_arg_stack[dollar_arg_stack_index] = (WORD_LIST *)NULL;
}

void
dispose_saved_dollar_vars ()
{
  if (!dollar_arg_stack || !dollar_arg_stack_index)
    return;

  dispose_words (dollar_arg_stack[dollar_arg_stack_index]);
  dollar_arg_stack[dollar_arg_stack_index] = (WORD_LIST *)NULL;
}

static int changed_dollar_vars = 0;

/* Have the dollar variables been reset to new values since we last
   checked? */
dollar_vars_changed ()
{
  return (changed_dollar_vars);
}

void
set_dollar_vars_unchanged ()
{
  changed_dollar_vars = 0;
}

void
set_dollar_vars_changed ()
{
  changed_dollar_vars  = 1;
}

/* Function called when one of the builtin commands detects a bad
   option. */
void
bad_option (s)
     char *s;
{
  builtin_error ("unknown option: %s", s);
}

/* Return a consed string which is the current working directory.
   FOR_WHOM is the name of the caller for error printing.  */
char *the_current_working_directory = (char *)NULL;

char *
get_working_directory (for_whom)
     char *for_whom;
{
  if (no_symbolic_links)
    {
      if (the_current_working_directory)
	free (the_current_working_directory);

      the_current_working_directory = (char *)NULL;
    }

  if (!the_current_working_directory)
    {
      char *directory;

      the_current_working_directory = xmalloc (MAXPATHLEN);
      directory = getwd (the_current_working_directory);
      if (!directory)
	{
	  if (for_whom && *for_whom)
	    fprintf (stderr, "%s: ", for_whom);
	  else
	    fprintf (stderr, "%s: ", get_name_for_error ());

	  fprintf (stderr, "could not get current directory: %s\n",
		   the_current_working_directory);

	  free (the_current_working_directory);
	  the_current_working_directory = (char *)NULL;
	  return (char *)NULL;
	}
    }

  return (savestring (the_current_working_directory));
}

/* Make NAME our internal idea of the current working directory. */
void
set_working_directory (name)
     char *name;
{
  if (the_current_working_directory)
    free (the_current_working_directory);

  the_current_working_directory = savestring (name);
}

#if defined (JOB_CONTROL)
/* Return the job spec found in LIST. */
get_job_spec (list)
     WORD_LIST *list;
{
  register char *word;
  int job = NO_JOB;
  int substring = 0;

  if (!list)
    return (current_job);

  word = list->word->word;

  if (!*word)
    return (current_job);

  if (*word == '%')
    word++;

  if (digit (*word) && (sscanf (word, "%d", &job) == 1))
    return (job - 1);

  switch (*word)
    {
    case 0:
    case '%':
    case '+':
      return (current_job);

    case '-':
      return (previous_job);

    case '?':			/* Substring search requested. */
      substring++;
      word++;
      goto find_string;

    default:
    find_string:
      {
	register int i, wl = strlen (word);
	for (i = 0; i < job_slots; i++)
	  {
	    if (jobs[i])
	      {
		register PROCESS *p = jobs[i]->pipe;
		do
		  {
		    if ((substring && strindex (p->command, word)) ||
			(strncmp (p->command, word, wl) == 0))
		      if (job != NO_JOB)
			{
			  builtin_error ("ambigious job spec: %s", word);
			  return (DUP_JOB);
			}
		      else
			job = i;

		    p = p->next;
		  }
		while (p != jobs[i]->pipe);
	      }
	  }
	return (job);
      }
    }
}
#endif /* JOB_CONTROL */

int parse_and_execute_level = 0;

/* How to force parse_and_execute () to clean up after itself. */
void
parse_and_execute_cleanup ()
{
  run_unwind_frame ("parse_and_execute_top");
}

/* Parse and execute the commands in STRING.  Returns whatever
   execute_command () returns.  This frees STRING.  INTERACT is
   the new value for `interactive' while the commands are being
   executed.  A value of -1 means don't change it. */
int
parse_and_execute (string, from_file, interact)
     char *string;
     char *from_file;
     int interact;
{
  int last_result = EXECUTION_SUCCESS;
  int code = 0, jump_to_top_level = 0;
  char *orig_string = string;

  /* Unwind protect this invocation of parse_and_execute (). */
  begin_unwind_frame ("parse_and_execute_top");
  unwind_protect_int (parse_and_execute_level);
  unwind_protect_jmp_buf (top_level);
  unwind_protect_int (indirection_level);
  if (interact != -1 && interactive != interact)
    unwind_protect_int (interactive);

#if defined (HISTORY)
  if (interactive_shell)
    {
      unwind_protect_int (remember_on_history);
#  if defined (BANG_HISTORY)
      unwind_protect_int (history_expansion_inhibited);
#  endif /* BANG_HISTORY */
    }
#endif /* HISTORY */

  add_unwind_protect (pop_stream, (char *)NULL);
  if (orig_string)
    add_unwind_protect (xfree, orig_string);
  end_unwind_frame ();

  parse_and_execute_level++;
  push_stream ();
  indirection_level++;
  if (interact != -1)
    interactive = interact;

#if defined (HISTORY)
  /* We don't remember text read by the shell this way on
     the history list, and we don't use !$ in shell scripts. */
  remember_on_history = 0;
#  if defined (BANG_HISTORY)
  history_expansion_inhibited = 1;
#  endif /* BANG_HISTORY */
#endif /* HISTORY */

  with_input_from_string (string, from_file);
  {
    COMMAND *command;

    while (*(bash_input.location.string))
      {
	if (interrupt_state)
	  {
	    last_result = EXECUTION_FAILURE;
	    break;
	  }

	/* Provide a location for functions which `longjmp (top_level)' to
	   jump to.  This prevents errors in substitution from restarting
	   the reader loop directly, for example. */
	code = setjmp (top_level);

	if (code)
	  {
	    jump_to_top_level = 0;
	    switch (code)
	      {
	      case FORCE_EOF:
	      case EXITPROG:
		run_unwind_frame ("pe_dispose");
		/* Remember to call longjmp (top_level) after the old
		   value for it is restored. */
		jump_to_top_level = 1;
		goto out;

	      case DISCARD:
	        dispose_command (command);
		run_unwind_frame ("pe_dispose");
		last_command_exit_value = 1;
		continue;

	      default:
		programming_error ("bad jump to top_level: %d", code);
		break;
	      }
	  }
	  
	if (parse_command () == 0)
	  {
	    if ((command = global_command) != (COMMAND *)NULL)
	      {
		struct fd_bitmap *bitmap;

		bitmap = new_fd_bitmap (FD_BITMAP_SIZE);
		begin_unwind_frame ("pe_dispose");
		add_unwind_protect (dispose_fd_bitmap, bitmap);

		global_command = (COMMAND *)NULL;

#if defined (ONESHOT)
	        if (startup_state == 2 && *bash_input.location.string == '\0' &&
		    command->type == cm_simple && !command->redirects &&
		    !command->value.Simple->redirects)
		  {
		    command->flags |= CMD_NO_FORK;
		    command->value.Simple->flags |= CMD_NO_FORK;
		  }
#endif /* ONESHOT */
    
		last_result = execute_command_internal
		    (command, 0, NO_PIPE, NO_PIPE, bitmap);

		dispose_command (command);
		run_unwind_frame ("pe_dispose");
	      }
	  }
	else
	  {
	    last_result = EXECUTION_FAILURE;

	    /* Since we are shell compatible, syntax errors in a script
	       abort the execution of the script.  Right? */
	    break;
	  }
      }
  }

 out:

  run_unwind_frame ("parse_and_execute_top");

  if (interrupt_state && parse_and_execute_level == 0)
    {
      /* An interrupt during non-interactive execution in an
         interactive shell (e.g. via $PROMPT_COMMAND) should
         not cause the shell to exit. */
      interactive = interactive_shell;
      throw_to_top_level ();
    }

  if (jump_to_top_level)
    longjmp (top_level, code);

  return (last_result);
}

/* Return the address of the builtin named NAME.
   DISABLED_OKAY means find it even if the builtin is disabled. */
static Function *
builtin_address_internal (name, disabled_okay)
     char *name;
     int disabled_okay;
{
  int hi, lo, mid, j;

  hi = num_shell_builtins - 1;
  lo = 0;

  while (lo <= hi)
    {
      mid = (lo + hi) / 2;

      j = shell_builtins[mid].name[0] - name[0];

      if (j == 0)
	j = strcmp (shell_builtins[mid].name, name);

      if (j == 0)
	{
	  /* It must have a function pointer.  It must be enabled, or we
	     must have explicitly allowed disabled functions to be found. */
	  if (shell_builtins[mid].function &&
	      ((shell_builtins[mid].flags & BUILTIN_ENABLED) || disabled_okay))
	    return (shell_builtins[mid].function);
	  else
	    return ((Function *)NULL);
	}
      if (j > 0)
	hi = mid - 1;
      else
	lo = mid + 1;
    }
  return ((Function *)NULL);
}

/* Perform a binary search and return the address of the builtin function
   whose name is NAME.  If the function couldn't be found, or the builtin
   is disabled or has no function associated with it, return NULL. */
Function *
find_shell_builtin (name)
	char *name;
{
  return (builtin_address_internal (name, 0));
}

/* Return the address of builtin with NAME, irregardless of its state of
   enableness. */
Function *
builtin_address (name)
     char *name;
{
  return (builtin_address_internal (name, 1));
}

static int
shell_builtin_compare (sbp1, sbp2)
     struct builtin *sbp1, *sbp2;
{
  int result;

  if ((result = sbp1->name[0] - sbp2->name[0]) == 0)
    result = strcmp (sbp1->name, sbp2->name);

  return (result);
}

/* Sort the table of shell builtins so that the binary search will work
   in find_shell_builtin. */
void
initialize_shell_builtins ()
{
  qsort (shell_builtins, num_shell_builtins, sizeof (struct builtin),
    shell_builtin_compare);
}

/* Return a new string which is the quoted version of STRING.  This is used
   by alias and trap. */
char *
single_quote (string)
     char *string;
{
  register int i, j, c;
  char *result;

  result = (char *)xmalloc (3 + (3 * strlen (string)));

  result[0] = '\'';

  for (i = 0, j = 1; string && (c = string[i]); i++)
    {
      result[j++] = c;

      if (c == '\'')
	{
	  result[j++] = '\\';	/* insert escaped single quote */
	  result[j++] = '\'';
	  result[j++] = '\'';	/* start new quoted string */
	}
    }

  result[j++] = '\'';
  result[j] = '\0';

  return (result);
}

char *
double_quote (string)
     char *string;
{
  register int i, j, c;
  char *result;

  result = (char *)xmalloc (3 + (3 * strlen (string)));

  result[0] = '"';

  for (i = 0, j = 1; string && (c = string[i]); i++)
    {
      switch (c)
        {
	case '"':
	case '$':
	case '`':
	case '\\':
	  result[j++] = '\\';
	default:
	  result[j++] = c;
	  break;
        }
    }

  result[j++] = '"';
  result[j] = '\0';

  return (result);
}