434 lines
11 KiB
Modula-2
434 lines
11 KiB
Modula-2
This file is enable.def, from which is created enable.c.
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It implements the builtin "enable" in Bash.
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Copyright (C) 1987, 1989, 1991 Free Software Foundation, Inc.
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This file is part of GNU Bash, the Bourne Again SHell.
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Bash is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 1, or (at your option) any later
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version.
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Bash is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License along
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with Bash; see the file COPYING. If not, write to the Free Software
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Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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$PRODUCES enable.c
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$BUILTIN enable
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$FUNCTION enable_builtin
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$SHORT_DOC enable [-pnds] [-a] [-f filename] [name ...]
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Enable and disable builtin shell commands. This allows
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you to use a disk command which has the same name as a shell
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builtin. If -n is used, the NAMEs become disabled; otherwise
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NAMEs are enabled. For example, to use the `test' found on your
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path instead of the shell builtin version, type `enable -n test'.
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On systems supporting dynamic loading, the -f option may be used
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to load new builtins from the shared object FILENAME. The -d
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option will delete a builtin previously loaded with -f. If no
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non-option names are given, or the -p option is supplied, a list
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of builtins is printed. The -a option means to print every builtin
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with an indication of whether or not it is enabled. The -s option
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restricts the output to the Posix.2 `special' builtins. The -n
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option displays a list of all disabled builtins.
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$END
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#include <config.h>
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#if defined (HAVE_UNISTD_H)
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# ifdef _MINIX
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# include <sys/types.h>
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# endif
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# include <unistd.h>
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#endif
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#include <stdio.h>
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#include "../bashansi.h"
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#include "../shell.h"
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#include "../builtins.h"
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#include "../flags.h"
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#include "common.h"
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#include "bashgetopt.h"
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#if defined (HAVE_DLOPEN) && defined (HAVE_DLSYM)
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static int dyn_load_builtin ();
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#endif
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#if defined (HAVE_DLCLOSE)
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static int dyn_unload_builtin ();
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#endif
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#define ENABLED 1
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#define DISABLED 2
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#define SPECIAL 4
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#define AFLAG 0x01
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#define DFLAG 0x02
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#define FFLAG 0x04
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#define NFLAG 0x08
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#define PFLAG 0x10
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#define SFLAG 0x20
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static int enable_shell_command ();
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static void list_some_builtins ();
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/* Enable/disable shell commands present in LIST. If list is not specified,
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then print out a list of shell commands showing which are enabled and
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which are disabled. */
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int
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enable_builtin (list)
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WORD_LIST *list;
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{
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int result, flags;
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int opt, filter;
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#if defined (HAVE_DLOPEN) && defined (HAVE_DLSYM)
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char *filename;
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#endif
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result = EXECUTION_SUCCESS;
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flags = 0;
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reset_internal_getopt ();
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while ((opt = internal_getopt (list, "adnpsf:")) != -1)
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{
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switch (opt)
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{
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case 'a':
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flags |= AFLAG;
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break;
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case 'n':
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flags |= NFLAG;
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break;
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case 'p':
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flags |= PFLAG;
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break;
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case 's':
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flags |= SFLAG;
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break;
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case 'f':
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#if defined (HAVE_DLOPEN) && defined (HAVE_DLSYM)
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flags |= FFLAG;
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filename = list_optarg;
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break;
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#else
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builtin_error ("dynamic loading not available");
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return (EX_USAGE);
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#endif
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#if defined (HAVE_DLCLOSE)
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case 'd':
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flags |= DFLAG;
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break;
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#else
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builtin_error ("dynamic loading not available");
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return (EX_USAGE);
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#endif /* HAVE_DLCLOSE */
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default:
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builtin_usage ();
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return (EX_USAGE);
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}
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}
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list = loptend;
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#if defined (RESTRICTED_SHELL)
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/* Restricted shells cannot load new builtins. */
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if (restricted && (flags & (FFLAG|DFLAG)))
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{
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builtin_error ("restricted");
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return (EXECUTION_FAILURE);
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}
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#endif
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if (list == 0 || (flags & PFLAG))
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{
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filter = (flags & AFLAG) ? (ENABLED | DISABLED)
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: (flags & NFLAG) ? DISABLED : ENABLED;
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if (flags & SFLAG)
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filter |= SPECIAL;
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list_some_builtins (filter);
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}
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#if defined (HAVE_DLOPEN) && defined (HAVE_DLSYM)
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else if (flags & FFLAG)
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{
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filter = (flags & NFLAG) ? DISABLED : ENABLED;
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if (flags & SFLAG)
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filter |= SPECIAL;
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result = dyn_load_builtin (list, filter, filename);
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}
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#endif
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#if defined (HAVE_DLCLOSE)
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else if (flags & DFLAG)
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{
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while (list)
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{
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opt = dyn_unload_builtin (list->word->word);
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if (opt == EXECUTION_FAILURE)
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result = EXECUTION_FAILURE;
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list = list->next;
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}
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}
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#endif
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else
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{
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while (list)
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{
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opt = enable_shell_command (list->word->word, flags & NFLAG);
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if (opt == EXECUTION_FAILURE)
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{
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builtin_error ("%s: not a shell builtin", list->word->word);
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result = EXECUTION_FAILURE;
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}
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list = list->next;
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}
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}
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return (result);
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}
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/* List some builtins.
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FILTER is a mask with two slots: ENABLED and DISABLED. */
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static void
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list_some_builtins (filter)
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int filter;
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{
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register int i;
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for (i = 0; i < num_shell_builtins; i++)
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{
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if (shell_builtins[i].function == 0 || (shell_builtins[i].flags & BUILTIN_DELETED))
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continue;
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if ((filter & SPECIAL) &&
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(shell_builtins[i].flags & SPECIAL_BUILTIN) == 0)
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continue;
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if ((filter & ENABLED) && (shell_builtins[i].flags & BUILTIN_ENABLED))
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printf ("enable %s\n", shell_builtins[i].name);
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else if ((filter & DISABLED) &&
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((shell_builtins[i].flags & BUILTIN_ENABLED) == 0))
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printf ("enable -n %s\n", shell_builtins[i].name);
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}
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}
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/* Enable the shell command NAME. If DISABLE_P is non-zero, then
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disable NAME instead. */
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static int
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enable_shell_command (name, disable_p)
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char *name;
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int disable_p;
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{
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struct builtin *b;
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b = builtin_address_internal (name, 1);
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if (b == 0)
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return (EXECUTION_FAILURE);
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if (disable_p)
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b->flags &= ~BUILTIN_ENABLED;
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else
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b->flags |= BUILTIN_ENABLED;
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return (EXECUTION_SUCCESS);
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}
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#if defined (HAVE_DLOPEN) && defined (HAVE_DLSYM)
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#if defined (HAVE_DLFCN_H)
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# include <dlfcn.h>
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#endif
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static int
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dyn_load_builtin (list, flags, filename)
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WORD_LIST *list;
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int flags;
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char *filename;
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{
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WORD_LIST *l;
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void *handle;
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int total, size, new, replaced;
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char *struct_name, *name;
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struct builtin **new_builtins, *b, *new_shell_builtins, *old_builtin;
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if (list == 0)
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return (EXECUTION_FAILURE);
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#ifndef RTLD_LAZY
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#define RTLD_LAZY 1
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#endif
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#if defined (_AIX)
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handle = dlopen (filename, RTLD_NOW|RTLD_GLOBAL);
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#else
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handle = dlopen (filename, RTLD_LAZY);
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#endif /* !_AIX */
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if (handle == 0)
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{
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builtin_error ("cannot open shared object %s: %s", filename, dlerror ());
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return (EXECUTION_FAILURE);
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}
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for (new = 0, l = list; l; l = l->next, new++)
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;
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new_builtins = (struct builtin **)xmalloc (new * sizeof (struct builtin *));
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/* For each new builtin in the shared object, find it and its describing
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structure. If this is overwriting an existing builtin, do so, otherwise
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save the loaded struct for creating the new list of builtins. */
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for (replaced = new = 0; list; list = list->next)
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{
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name = list->word->word;
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size = strlen (name);
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struct_name = xmalloc (size + 8);
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strcpy (struct_name, name);
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strcpy (struct_name + size, "_struct");
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b = (struct builtin *)dlsym (handle, struct_name);
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if (b == 0)
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{
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builtin_error ("cannot find %s in shared object %s: %s", struct_name,
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filename, dlerror ());
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free (struct_name);
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continue;
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}
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free (struct_name);
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b->flags &= ~STATIC_BUILTIN;
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if (flags & SPECIAL)
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b->flags |= SPECIAL_BUILTIN;
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b->handle = handle;
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if (old_builtin = builtin_address_internal (name, 1))
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{
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replaced++;
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FASTCOPY ((char *)b, (char *)old_builtin, sizeof (struct builtin));
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}
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else
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new_builtins[new++] = b;
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}
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if (replaced == 0 && new == 0)
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{
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free (new_builtins);
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dlclose (handle);
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return (EXECUTION_FAILURE);
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}
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if (new)
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{
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total = num_shell_builtins + new;
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size = (total + 1) * sizeof (struct builtin);
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new_shell_builtins = (struct builtin *)xmalloc (size);
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FASTCOPY ((char *)shell_builtins, (char *)new_shell_builtins,
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num_shell_builtins * sizeof (struct builtin));
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for (replaced = 0; replaced < new; replaced++)
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FASTCOPY ((char *)new_builtins[replaced],
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(char *)&new_shell_builtins[num_shell_builtins + replaced],
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sizeof (struct builtin));
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new_shell_builtins[total].name = (char *)0;
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new_shell_builtins[total].function = (Function *)0;
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new_shell_builtins[total].flags = 0;
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if (shell_builtins != static_shell_builtins)
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free (shell_builtins);
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shell_builtins = new_shell_builtins;
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num_shell_builtins = total;
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initialize_shell_builtins ();
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}
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free (new_builtins);
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return (EXECUTION_SUCCESS);
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}
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#endif
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#if defined (HAVE_DLCLOSE)
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static void
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delete_builtin (b)
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struct builtin *b;
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{
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int ind, size;
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struct builtin *new_shell_builtins;
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/* XXX - funky pointer arithmetic - XXX */
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#ifdef __STDC__
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ind = b - shell_builtins;
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#else
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ind = ((int)b - (int)shell_builtins) / sizeof (struct builtin);
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#endif
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size = num_shell_builtins * sizeof (struct builtin);
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new_shell_builtins = (struct builtin *)xmalloc (size);
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/* Copy shell_builtins[0]...shell_builtins[ind - 1] to new_shell_builtins */
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if (ind)
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FASTCOPY ((char *)shell_builtins, (char *)new_shell_builtins,
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ind * sizeof (struct builtin));
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/* Copy shell_builtins[ind+1]...shell_builtins[num_shell_builtins to
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new_shell_builtins, starting at ind. */
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FASTCOPY ((char *)(&shell_builtins[ind+1]),
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(char *)(&new_shell_builtins[ind]),
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(num_shell_builtins - ind) * sizeof (struct builtin));
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if (shell_builtins != static_shell_builtins)
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free (shell_builtins);
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/* The result is still sorted. */
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num_shell_builtins--;
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shell_builtins = new_shell_builtins;
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}
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static int
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dyn_unload_builtin (name)
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char *name;
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{
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struct builtin *b;
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void *handle;
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int ref, i;
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b = builtin_address_internal (name, 1);
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if (b == 0)
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{
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builtin_error ("%s: not a shell builtin", name);
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return (EXECUTION_FAILURE);
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}
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if (b->flags & STATIC_BUILTIN)
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{
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builtin_error ("%s: not dynamically loaded", name);
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return (EXECUTION_FAILURE);
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}
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handle = (void *)b->handle;
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for (ref = i = 0; i < num_shell_builtins; i++)
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{
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if (shell_builtins[i].handle == b->handle)
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ref++;
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}
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/* Don't remove the shared object unless the reference count of builtins
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using it drops to zero. */
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if (ref == 1 && dlclose (handle) != 0)
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{
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builtin_error ("cannot delete %s: %s", name, dlerror ());
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return (EXECUTION_FAILURE);
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}
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/* Now remove this entry from the builtin table and reinitialize. */
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delete_builtin (b);
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return (EXECUTION_SUCCESS);
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}
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#endif
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