--- /dev/null
+/*
+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.
+
+*******************************************************************************
+******************************************************************************/
+
+
+\f
+#include <dlfcn.h>
+#include <stdio.h>
+#include <strings.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <readline/readline.h>
+#include <readline/history.h>
+
+
+\f
+/* 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 ) ;
+
+
+\f
+/* 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 ;
+
+
+\f
+/* 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 ;
+}
+
+
+\f
+/* 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" ) ;
+}
+
+
+\f
+/* 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 ) ;
+ }
+}
+
+
+\f
+/* 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 ;
+ }
+}
+
+
+\f
+/* 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 ) ;
+}
+
+
+\f
+/* 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 ) ;
+}
+
+
+\f
+/* 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 )
+ ) ;
+ }
+}
OSDN Git Service
