readline/examples/rl-fgets.c - third_party/binutils-gdb - Git at Google

 /*
 Date: Tue, 16 Mar 2004 19:38:40 -0800
 From: Harold Levy <Harold.Levy@synopsys.com>
 Subject: fgets(stdin) --> readline() redirector
 To: chet@po.cwru.edu

 Hi Chet,

 Here is something you may find useful enough to include in the readline
 distribution.  It is a shared library that redirects calls to fgets(stdin)
 to readline() via LD_PRELOAD, and it supports a custom prompt and list of
 command names.  Many people have asked me for this file, so I thought I'd
 pass it your way in hope of just including it with readline to begin with.

 Best Regards,

 -Harold
 */

 /******************************************************************************
 *******************************************************************************

   FILE NAME:    fgets.c                  TARGET:   libfgets.so
   AUTHOR:       Harold Levy              VERSION:  1.0
                 hlevy@synopsys.com

   ABSTRACT:  Customize fgets() behavior via LD_PRELOAD in the following ways:

     -- If fgets(stdin) is called, redirect to GNU readline() to obtain
        command-line editing, file-name completion, history, etc.

     -- A list of commands for command-name completion can be configured by
        setting the environment-variable FGETS_COMMAND_FILE to a file containing
        the list of commands to be used.

     -- Command-line editing with readline() works best when the prompt string
        is known; you can set this with the FGETS_PROMPT environment variable.

     -- There special strings that libfgets will interpret as internal commands:

            _fgets_reset_    reset the command list

            _fgets_dump_     dump status

            _fgets_debug_    toggle debug messages

   HOW TO BUILD:  Here are examples of how to build libfgets.so on various
   platforms; you will have to add -I and -L flags to configure access to
   the readline header and library files.

   (32-bit builds with gcc)
   AIX:   gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldl -lreadline -ltermcap
   HP-UX: gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldld -lreadline
   Linux: gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldl -lreadline
   SunOS: gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldl -lgen -lreadline

   (64-bit builds without gcc)
   SunOS: SUNWspro/bin/cc -D_LARGEFILE64_SOURCE=1 -xtarget=ultra -xarch=v9 \
            -KPIC fgets.c -Bdynamic -lc -ldl -lgen -ltermcap -lreadline

   HOW TO USE:  Different operating systems have different levels of support
   for the LD_PRELOAD concept.  The generic method for 32-bit platforms is to
   put libtermcap.so, libfgets.so, and libreadline.so (with absolute paths)
   in the LD_PRELOAD environment variable, and to put their parent directories
   in the LD_LIBRARY_PATH environment variable.  Unfortunately there is no
   generic method for 64-bit platforms; e.g. for 64-bit SunOS, you would have
   to build both 32-bit and 64-bit libfgets and libreadline libraries, and
   use the LD_FLAGS_32 and LD_FLAGS_64 environment variables with preload and
   library_path configurations (a mix of 32-bit and 64-bit calls are made under
   64-bit SunOS).

   EXAMPLE WRAPPER:  Here is an example shell script wrapper around the
   program "foo" that uses fgets() for command-line input:

       #!/bin/csh
       #### replace this with the libtermcap.so directory:
       set dir1 = "/usr/lib"
       #### replace this with the libfgets.so directory:
       set dir2 = "/usr/fgets"
       #### replace this with the libreadline.so directory:
       set dir3 = "/usr/local/lib"
       set lib1 = "${dir1}/libtermcap.so"
       set lib2 = "${dir2}/libfgets.so"
       set lib3 = "${dir3}/libreadline.so"
       if ( "${?LD_PRELOAD}" ) then
         setenv LD_PRELOAD "${lib1}:${lib2}:${lib3}:${LD_PRELOAD}"
       else
         setenv LD_PRELOAD "${lib1}:${lib2}:${lib3}"
       endif
       if ( "${?LD_LIBRARY_PATH}" ) then
         setenv LD_LIBRARY_PATH "${dir1}:${dir2}:${dir3}:${LD_LIBRARY_PATH}"
       else
         setenv LD_LIBRARY_PATH "${dir1}:${dir2}:${dir3}"
       endif
       setenv FGETS_COMMAND_FILE "${dir2}/foo.commands"
       setenv FGETS_PROMPT       "foo> "
       exec "foo" $*

   Copyright (C)©2003-2004 Harold Levy.

   This code links to the GNU readline library, and as such is bound by the
   terms of the GNU General Public License as published by the Free Software
   Foundation, either version 2 or (at your option) any later version.

   The GNU General Public License is often shipped with GNU software, and is
   generally kept in a file called COPYING or LICENSE.  If you do not have a
   copy of the license, write to the Free Software Foundation, 59 Temple Place,
   Suite 330, Boston, MA 02111 USA.

   This program 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.

 *******************************************************************************
 ******************************************************************************/


 #include <dlfcn.h>
 #include <stdio.h>
 #include <strings.h>
 #include <stdlib.h>
 #include <unistd.h>

 #include <readline/readline.h>
 #include <readline/history.h>


 /* for dynamically connecting to the native fgets() */
 #if defined(RTLD_NEXT)
 #define REAL_LIBC RTLD_NEXT
 #else
 #define REAL_LIBC ((void *) -1L)
 #endif
 typedef char * ( * fgets_t ) ( char * s, int n, FILE * stream ) ;


 /* private data */
 /* -- writeable data is stored in the shared library's data segment
    -- every process that uses the shared library gets a private memory copy of
       its entire data segment
    -- static data in the shared library is not copied to the application
    -- only read-only (i.e. 'const') data is stored in the shared library's
       text segment
 */
 static char ** my_fgets_names           = NULL ;
 static int     my_fgets_number_of_names = 0    ;
 static int     my_fgets_debug_flag      = 0    ;


 /* invoked with _fgets_reset_ */
 static void
 my_fgets_reset (
   void
 ) {
   if ( my_fgets_names && (my_fgets_number_of_names > 0) ) {
     int i ;
     if ( my_fgets_debug_flag ) {
       printf ( "libfgets:  removing command list\n" ) ;
     }
     for ( i = 0 ; i < my_fgets_number_of_names ; i ++ ) {
       if ( my_fgets_names[i] ) free ( my_fgets_names[i] ) ;
     }
     free ( my_fgets_names ) ;
   }
   my_fgets_names = NULL ;
   my_fgets_number_of_names = 0 ;
 }


 /* invoked with _fgets_dump_ */
 static void
 my_fgets_dump (
   void
 ) {
   char * s ;
   printf ( "\n" ) ;
   s = getenv ( "FGETS_PROMPT" ) ;
   printf ( "FGETS_PROMPT       = %s\n", s ? s : "" ) ;
   s = getenv ( "FGETS_COMMAND_FILE" ) ;
   printf ( "FGETS_COMMAND_FILE = %s\n", s ? s : "" ) ;
   printf ( "debug flag         = %d\n", my_fgets_debug_flag ) ;
   printf ( "#commands          = %d\n", my_fgets_number_of_names ) ;
   if ( my_fgets_debug_flag ) {
     if ( my_fgets_names && (my_fgets_number_of_names > 0) ) {
       int i ;
       for ( i = 0 ; i < my_fgets_number_of_names ; i ++ ) {
         printf ( "%s\n", my_fgets_names[i] ) ;
       }
     }
   }
   printf ( "\n" ) ;
 }


 /* invoked with _fgets_debug_ */
 static void
 my_fgets_debug_toggle (
   void
 ) {
   my_fgets_debug_flag = my_fgets_debug_flag ? 0 : 1 ;
   if ( my_fgets_debug_flag ) {
     printf ( "libfgets:  debug flag = %d\n", my_fgets_debug_flag ) ;
   }
 }


 /* read the command list if needed, return the i-th name */
 static char *
 my_fgets_lookup (
   int index
 ) {
   if ( (! my_fgets_names) || (! my_fgets_number_of_names) ) {
     char * fname ;
     FILE * fp ;
     fgets_t _fgets ;
     int i ;
     char buf1[256], buf2[256] ;
     fname = getenv ( "FGETS_COMMAND_FILE" ) ;
     if ( ! fname ) {
       if ( my_fgets_debug_flag ) {
         printf ( "libfgets:  empty or unset FGETS_COMMAND_FILE\n" ) ;
       }
       return NULL ;
     }
     fp = fopen ( fname, "r" ) ;
     if ( ! fp ) {
       if ( my_fgets_debug_flag ) {
         printf ( "libfgets:  cannot open '%s' for reading\n", fname ) ;
       }
       return NULL ;
     }
     _fgets = (fgets_t) dlsym ( REAL_LIBC, "fgets" ) ;
     if ( ! _fgets ) {
       fprintf ( stderr,
         "libfgets:  failed to dynamically link to native fgets()\n"
       ) ;
       return NULL ;
     }
     for ( i = 0 ; _fgets(buf1,255,fp) ; i ++ ) ;
     if ( ! i ) { fclose(fp) ; return NULL ; }
     my_fgets_names = (char**) calloc ( i, sizeof(char*) ) ;
     rewind ( fp ) ;
     i = 0 ;
     while ( _fgets(buf1,255,fp) ) {
       buf1[255] = 0 ;
       if ( 1 == sscanf(buf1,"%s",buf2) ) {
         my_fgets_names[i] = strdup(buf2) ;
         i ++ ;
       }
     }
     fclose ( fp ) ;
     my_fgets_number_of_names = i ;
     if ( my_fgets_debug_flag ) {
       printf ( "libfgets:  successfully read %d commands\n", i ) ;
     }
   }
   if ( index < my_fgets_number_of_names ) {
     return my_fgets_names[index] ;
   } else {
     return NULL ;
   }
 }


 /* generate a list of partial name matches for readline() */
 static char *
 my_fgets_generator (
   const char * text,
   int          state
 )
 {
   static int list_index, len ;
   char *     name ;
   if ( ! state ) {
     list_index = 0 ;
     len = strlen ( text ) ;
   }
   while ( ( name = my_fgets_lookup(list_index) ) ) {
     list_index ++ ;
     if ( ! strncmp ( name, text, len ) ) {
       return ( strdup ( name ) ) ;
     }
   }
   return ( NULL ) ;
 }


 /* partial name completion callback for readline() */
 static char **
 my_fgets_completion (
   const char * text,
   int          start,
   int          end
 )
 {
   char ** matches ;
   matches = NULL ;
   if ( ! start ) {
     matches = rl_completion_matches ( text, my_fgets_generator ) ;
   }
   return ( matches ) ;
 }


 /* fgets() intercept */
 char *
 fgets (
   char * s,
   int    n,
   FILE * stream
 )
 {
   if ( ! s ) return NULL ;
   if ( stream == stdin ) {
     char * prompt ;
     char * my_fgets_line ;
     rl_already_prompted = 1 ;
     rl_attempted_completion_function = my_fgets_completion ;
     rl_catch_signals = 1 ;
     rl_catch_sigwinch = 1 ;
     rl_set_signals () ;
     prompt = getenv ( "FGETS_PROMPT" ) ;
     for (
       my_fgets_line = 0 ; ! my_fgets_line ; my_fgets_line=readline(prompt)
     ) ;
     if ( ! strncmp(my_fgets_line, "_fgets_reset_", 13) ) {
       my_fgets_reset () ;
       free ( my_fgets_line ) ;
       strcpy ( s, "\n" ) ;
       return ( s ) ;
     }
     if ( ! strncmp(my_fgets_line, "_fgets_dump_", 12) ) {
       my_fgets_dump () ;
       free ( my_fgets_line ) ;
       strcpy ( s, "\n" ) ;
       return ( s ) ;
     }
     if ( ! strncmp(my_fgets_line, "_fgets_debug_", 13) ) {
       my_fgets_debug_toggle () ;
       free ( my_fgets_line ) ;
       strcpy ( s, "\n" ) ;
       return ( s ) ;
     }
     (void) strncpy ( s, my_fgets_line, n-1 ) ;
     (void) strcat ( s, "\n" ) ;
     if ( *my_fgets_line ) add_history ( my_fgets_line ) ;
     free ( my_fgets_line ) ;
     return ( s ) ;
   } else {
     static fgets_t _fgets ;
     _fgets = (fgets_t) dlsym ( REAL_LIBC, "fgets" ) ;
     if ( ! _fgets ) {
       fprintf ( stderr,
         "libfgets:  failed to dynamically link to native fgets()\n"
       ) ;
       strcpy ( s, "\n" ) ;
       return ( s ) ;
     }
     return (
       _fgets ( s, n, stream )
     ) ;
   }
 }
	/*
	Date: Tue, 16 Mar 2004 19:38:40 -0800
	From: Harold Levy <Harold.Levy@synopsys.com>
	Subject: fgets(stdin) --> readline() redirector
	To: chet@po.cwru.edu

	Hi Chet,

	Here is something you may find useful enough to include in the readline
	distribution. It is a shared library that redirects calls to fgets(stdin)
	to readline() via LD_PRELOAD, and it supports a custom prompt and list of
	command names. Many people have asked me for this file, so I thought I'd
	pass it your way in hope of just including it with readline to begin with.

	Best Regards,

	-Harold
	*/

	/******************************************************************************
	*******************************************************************************

	FILE NAME: fgets.c TARGET: libfgets.so
	AUTHOR: Harold Levy VERSION: 1.0
	hlevy@synopsys.com

	ABSTRACT: Customize fgets() behavior via LD_PRELOAD in the following ways:

	-- If fgets(stdin) is called, redirect to GNU readline() to obtain
	command-line editing, file-name completion, history, etc.

	-- A list of commands for command-name completion can be configured by
	setting the environment-variable FGETS_COMMAND_FILE to a file containing
	the list of commands to be used.

	-- Command-line editing with readline() works best when the prompt string
	is known; you can set this with the FGETS_PROMPT environment variable.

	-- There special strings that libfgets will interpret as internal commands:

	_fgets_reset_ reset the command list

	_fgets_dump_ dump status

	_fgets_debug_ toggle debug messages

	HOW TO BUILD: Here are examples of how to build libfgets.so on various
	platforms; you will have to add -I and -L flags to configure access to
	the readline header and library files.

	(32-bit builds with gcc)
	AIX: gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldl -lreadline -ltermcap
	HP-UX: gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldld -lreadline
	Linux: gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldl -lreadline
	SunOS: gcc -fPIC fgets.c -shared -o libfgets.so -lc -ldl -lgen -lreadline

	(64-bit builds without gcc)
	SunOS: SUNWspro/bin/cc -D_LARGEFILE64_SOURCE=1 -xtarget=ultra -xarch=v9 \
	-KPIC fgets.c -Bdynamic -lc -ldl -lgen -ltermcap -lreadline

	HOW TO USE: Different operating systems have different levels of support
	for the LD_PRELOAD concept. The generic method for 32-bit platforms is to
	put libtermcap.so, libfgets.so, and libreadline.so (with absolute paths)
	in the LD_PRELOAD environment variable, and to put their parent directories
	in the LD_LIBRARY_PATH environment variable. Unfortunately there is no
	generic method for 64-bit platforms; e.g. for 64-bit SunOS, you would have
	to build both 32-bit and 64-bit libfgets and libreadline libraries, and
	use the LD_FLAGS_32 and LD_FLAGS_64 environment variables with preload and
	library_path configurations (a mix of 32-bit and 64-bit calls are made under
	64-bit SunOS).

	EXAMPLE WRAPPER: Here is an example shell script wrapper around the
	program "foo" that uses fgets() for command-line input:

	#!/bin/csh
	#### replace this with the libtermcap.so directory:
	set dir1 = "/usr/lib"
	#### replace this with the libfgets.so directory:
	set dir2 = "/usr/fgets"
	#### replace this with the libreadline.so directory:
	set dir3 = "/usr/local/lib"
	set lib1 = "${dir1}/libtermcap.so"
	set lib2 = "${dir2}/libfgets.so"
	set lib3 = "${dir3}/libreadline.so"
	if ( "${?LD_PRELOAD}" ) then
	setenv LD_PRELOAD "${lib1}:${lib2}:${lib3}:${LD_PRELOAD}"
	else
	setenv LD_PRELOAD "${lib1}:${lib2}:${lib3}"
	endif
	if ( "${?LD_LIBRARY_PATH}" ) then
	setenv LD_LIBRARY_PATH "${dir1}:${dir2}:${dir3}:${LD_LIBRARY_PATH}"
	else
	setenv LD_LIBRARY_PATH "${dir1}:${dir2}:${dir3}"
	endif
	setenv FGETS_COMMAND_FILE "${dir2}/foo.commands"
	setenv FGETS_PROMPT "foo> "
	exec "foo" $*

	Copyright (C)©2003-2004 Harold Levy.

	This code links to the GNU readline library, and as such is bound by the
	terms of the GNU General Public License as published by the Free Software
	Foundation, either version 2 or (at your option) any later version.

	The GNU General Public License is often shipped with GNU software, and is
	generally kept in a file called COPYING or LICENSE. If you do not have a
	copy of the license, write to the Free Software Foundation, 59 Temple Place,
	Suite 330, Boston, MA 02111 USA.

	This program 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.

	*******************************************************************************
	******************************************************************************/



	#include <dlfcn.h>
	#include <stdio.h>
	#include <strings.h>
	#include <stdlib.h>
	#include <unistd.h>

	#include <readline/readline.h>
	#include <readline/history.h>



	/* for dynamically connecting to the native fgets() */
	#if defined(RTLD_NEXT)
	#define REAL_LIBC RTLD_NEXT
	#else
	#define REAL_LIBC ((void *) -1L)
	#endif
	typedef char * ( * fgets_t ) ( char * s, int n, FILE * stream ) ;



	/* private data */
	/* -- writeable data is stored in the shared library's data segment
	-- every process that uses the shared library gets a private memory copy of
	its entire data segment
	-- static data in the shared library is not copied to the application
	-- only read-only (i.e. 'const') data is stored in the shared library's
	text segment
	*/
	static char ** my_fgets_names = NULL ;
	static int my_fgets_number_of_names = 0 ;
	static int my_fgets_debug_flag = 0 ;



	/* invoked with _fgets_reset_ */
	static void
	my_fgets_reset (
	void
	) {
	if ( my_fgets_names && (my_fgets_number_of_names > 0) ) {
	int i ;
	if ( my_fgets_debug_flag ) {
	printf ( "libfgets: removing command list\n" ) ;
	}
	for ( i = 0 ; i < my_fgets_number_of_names ; i ++ ) {
	if ( my_fgets_names[i] ) free ( my_fgets_names[i] ) ;
	}
	free ( my_fgets_names ) ;
	}
	my_fgets_names = NULL ;
	my_fgets_number_of_names = 0 ;
	}



	/* invoked with _fgets_dump_ */
	static void
	my_fgets_dump (
	void
	) {
	char * s ;
	printf ( "\n" ) ;
	s = getenv ( "FGETS_PROMPT" ) ;
	printf ( "FGETS_PROMPT = %s\n", s ? s : "" ) ;
	s = getenv ( "FGETS_COMMAND_FILE" ) ;
	printf ( "FGETS_COMMAND_FILE = %s\n", s ? s : "" ) ;
	printf ( "debug flag = %d\n", my_fgets_debug_flag ) ;
	printf ( "#commands = %d\n", my_fgets_number_of_names ) ;
	if ( my_fgets_debug_flag ) {
	if ( my_fgets_names && (my_fgets_number_of_names > 0) ) {
	int i ;
	for ( i = 0 ; i < my_fgets_number_of_names ; i ++ ) {
	printf ( "%s\n", my_fgets_names[i] ) ;
	}
	}
	}
	printf ( "\n" ) ;
	}



	/* invoked with _fgets_debug_ */
	static void
	my_fgets_debug_toggle (
	void
	) {
	my_fgets_debug_flag = my_fgets_debug_flag ? 0 : 1 ;
	if ( my_fgets_debug_flag ) {
	printf ( "libfgets: debug flag = %d\n", my_fgets_debug_flag ) ;
	}
	}



	/* read the command list if needed, return the i-th name */
	static char *
	my_fgets_lookup (
	int index
	) {
	if ( (! my_fgets_names) \|\| (! my_fgets_number_of_names) ) {
	char * fname ;
	FILE * fp ;
	fgets_t _fgets ;
	int i ;
	char buf1[256], buf2[256] ;
	fname = getenv ( "FGETS_COMMAND_FILE" ) ;
	if ( ! fname ) {
	if ( my_fgets_debug_flag ) {
	printf ( "libfgets: empty or unset FGETS_COMMAND_FILE\n" ) ;
	}
	return NULL ;
	}
	fp = fopen ( fname, "r" ) ;
	if ( ! fp ) {
	if ( my_fgets_debug_flag ) {
	printf ( "libfgets: cannot open '%s' for reading\n", fname ) ;
	}
	return NULL ;
	}
	_fgets = (fgets_t) dlsym ( REAL_LIBC, "fgets" ) ;
	if ( ! _fgets ) {
	fprintf ( stderr,
	"libfgets: failed to dynamically link to native fgets()\n"
	) ;
	return NULL ;
	}
	for ( i = 0 ; _fgets(buf1,255,fp) ; i ++ ) ;
	if ( ! i ) { fclose(fp) ; return NULL ; }
	my_fgets_names = (char*) calloc ( i, sizeof(char) ) ;
	rewind ( fp ) ;
	i = 0 ;
	while ( _fgets(buf1,255,fp) ) {
	buf1[255] = 0 ;
	if ( 1 == sscanf(buf1,"%s",buf2) ) {
	my_fgets_names[i] = strdup(buf2) ;
	i ++ ;
	}
	}
	fclose ( fp ) ;
	my_fgets_number_of_names = i ;
	if ( my_fgets_debug_flag ) {
	printf ( "libfgets: successfully read %d commands\n", i ) ;
	}
	}
	if ( index < my_fgets_number_of_names ) {
	return my_fgets_names[index] ;
	} else {
	return NULL ;
	}
	}



	/* generate a list of partial name matches for readline() */
	static char *
	my_fgets_generator (
	const char * text,
	int state
	)
	{
	static int list_index, len ;
	char * name ;
	if ( ! state ) {
	list_index = 0 ;
	len = strlen ( text ) ;
	}
	while ( ( name = my_fgets_lookup(list_index) ) ) {
	list_index ++ ;
	if ( ! strncmp ( name, text, len ) ) {
	return ( strdup ( name ) ) ;
	}
	}
	return ( NULL ) ;
	}



	/* partial name completion callback for readline() */
	static char **
	my_fgets_completion (
	const char * text,
	int start,
	int end
	)
	{
	char ** matches ;
	matches = NULL ;
	if ( ! start ) {
	matches = rl_completion_matches ( text, my_fgets_generator ) ;
	}
	return ( matches ) ;
	}



	/* fgets() intercept */
	char *
	fgets (
	char * s,
	int n,
	FILE * stream
	)
	{
	if ( ! s ) return NULL ;
	if ( stream == stdin ) {
	char * prompt ;
	char * my_fgets_line ;
	rl_already_prompted = 1 ;
	rl_attempted_completion_function = my_fgets_completion ;
	rl_catch_signals = 1 ;
	rl_catch_sigwinch = 1 ;
	rl_set_signals () ;
	prompt = getenv ( "FGETS_PROMPT" ) ;
	for (
	my_fgets_line = 0 ; ! my_fgets_line ; my_fgets_line=readline(prompt)
	) ;
	if ( ! strncmp(my_fgets_line, "_fgets_reset_", 13) ) {
	my_fgets_reset () ;
	free ( my_fgets_line ) ;
	strcpy ( s, "\n" ) ;
	return ( s ) ;
	}
	if ( ! strncmp(my_fgets_line, "_fgets_dump_", 12) ) {
	my_fgets_dump () ;
	free ( my_fgets_line ) ;
	strcpy ( s, "\n" ) ;
	return ( s ) ;
	}
	if ( ! strncmp(my_fgets_line, "_fgets_debug_", 13) ) {
	my_fgets_debug_toggle () ;
	free ( my_fgets_line ) ;
	strcpy ( s, "\n" ) ;
	return ( s ) ;
	}
	(void) strncpy ( s, my_fgets_line, n-1 ) ;
	(void) strcat ( s, "\n" ) ;
	if ( *my_fgets_line ) add_history ( my_fgets_line ) ;
	free ( my_fgets_line ) ;
	return ( s ) ;
	} else {
	static fgets_t _fgets ;
	_fgets = (fgets_t) dlsym ( REAL_LIBC, "fgets" ) ;
	if ( ! _fgets ) {
	fprintf ( stderr,
	"libfgets: failed to dynamically link to native fgets()\n"
	) ;
	strcpy ( s, "\n" ) ;
	return ( s ) ;
	}
	return (
	_fgets ( s, n, stream )
	) ;
	}
	}