This file is source.def, from which is created source.c.
It implements the builtins "." and  "source" in Bash.

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.

$PRODUCES source.c

$BUILTIN source
$FUNCTION source_builtin
$SHORT_DOC source filename
Read and execute commands from FILENAME and return.  The pathnames
in $PATH are used to find the directory containing FILENAME.
$END
$BUILTIN .
$DOCNAME dot
$FUNCTION source_builtin
$SHORT_DOC . [filename]
Read and execute commands from FILENAME and return.  The pathnames
in $PATH are used to find the directory containing FILENAME.
$END
/* source.c - Implements the `.' and `source' builtins. */

#include <sys/types.h>
#include <sys/file.h>
#include <errno.h>
#include "../shell.h"
#include "../posixstat.h"
#include "../filecntl.h"

extern int errno;

/* Read and execute commands from the file passed as argument.  Guess what.
   This cannot be done in a subshell, since things like variable assignments
   take place in there.  So, I open the file, place it into a large string,
   close the file, and then execute the string. */
source_builtin (list)
     WORD_LIST *list;
{
  extern int return_catch_flag, return_catch_value;
  extern jmp_buf return_catch;
  int result, return_val;

  /* Assume the best. */
  result = EXECUTION_SUCCESS;

  if (list)
    {
      extern char *find_path_file ();
      char *string, *filename, *tempfile;
      struct stat finfo;
      int fd, tt;

      tempfile = find_path_file (list->word->word);

      if (!tempfile)
	tempfile = savestring (list->word->word);

      filename = (char *)alloca (1 + strlen (tempfile));
      strcpy (filename, tempfile);
      free (tempfile);

      if (stat (filename, &finfo) == -1 ||
	  (fd = open (filename, O_RDONLY)) == -1)
	goto file_error_exit;

      string = (char *)xmalloc (1 + finfo.st_size);
      tt = read (fd, string, finfo.st_size);
      string[finfo.st_size] = '\0';

      /* Close the open file, preserving the state of errno. */
      { int temp = errno; close (fd); errno = temp; }

      if (tt != finfo.st_size)
	{
	  free (string);

	file_error_exit:
	  file_error (filename);
#if defined (ALLOW_RIGID_POSIX_COMPLIANCE)
	  /* POSIX shells exit if non-interactive and file error. */
	  if (getenv ("POSIX_PENDANTIC"))
	    {
	      extern int interactive_shell;

	      if (!interactive_shell)
		longjmp (top_level, EXITPROG);
	    }
#endif /* ALLOW_RIGID_POSIX_COMPLIANCE */
	  return (EXECUTION_FAILURE);
	}

      if (tt > 80)
	tt = 80;

      if (check_binary_file (string, tt))
	{
	  free (string);
	  builtin_error ("%s: cannot execute binary file", filename);
	  return (EX_BINARY_FILE);
	}

      begin_unwind_frame ("File Sourcing");

      if (list->next)
	{
	  extern void pop_dollar_vars (), push_dollar_vars ();

	  push_dollar_vars ();
	  add_unwind_protect ((Function *)pop_dollar_vars, (char *)NULL);
	  remember_args (list->next, 1);
	}

      unwind_protect_int (return_catch_flag);
      unwind_protect_jmp_buf (return_catch);

      return_catch_flag++;
      return_val = setjmp (return_catch);

      if (return_val)
	parse_and_execute_cleanup ();
      else
	result = parse_and_execute (string, filename);

      run_unwind_frame ("File Sourcing");

      /* If RETURN_VAL is non-zero, then we return the value given
	 to return_builtin (), since that is how we got here. */
      if (return_val)
	result = return_catch_value;
    }
  return (result);
}