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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* alias.c is a C version of the alias.sh wrapper (which links ksh
* builtins to commands in /usr/bin/, e.g. calling this wrapper as
* /usr/bin/alias will call the ksh "alias" builtin, running it as
* /usr/bin/cut will call the ksh "cut" builtin etc.
*/
#include <shell.h>
#include <nval.h>
#include <cmdext.h>
#include <stdio.h>
typedef struct {
const char *name;
int (* func)(int, char **, void *);
} bfastpathrec;
/*
* We've disabled the "fastpath" codepath for some commands below
* because it causes a paradoxon for large input files (as used by
* ON PerfPIT for testing). For /usr/bin/rev (where the issue was
* first discovered) it looks like this:
* - for small files like /etc/profile the fastpath is faster in a loop
* with 1000 iterations (8 seconds with fastpath, 14 seconds without
* fastpath)
* - for large files (/usr/pub/UTF-8 replicated until the test file
* reaches 24884706 bytes) the benchmark reverses: The fastpath now
* needs 40 seconds and without fastpath it needs 30 seconds (for 100
* iterations).
*/
#if 0
#define ENABLE_PERFORMANCE_PARADOXON 1
#endif
/*
* List of libcmd builtins which do not require a |Shell_t| context.
* This list was automatically generated from <ast/cmdext.h>
*/
static const
bfastpathrec fastpath_builtins[] =
{
/* This list must be alphabetically sorted for |strcmp()| usage */
{ "basename", b_basename },
{ "cat", b_cat },
{ "chmod", b_chmod },
#ifdef ENABLE_PERFORMANCE_PARADOXON
{ "cksum", b_cksum },
#endif /* ENABLE_PERFORMANCE_PARADOXON */
{ "cmp", b_cmp },
{ "comm", b_comm },
{ "cp", b_cp },
{ "cut", b_cut },
{ "date", b_date },
{ "dirname", b_dirname },
{ "egrep", b_egrep },
{ "expr", b_expr },
{ "fds", b_fds },
{ "fgrep", b_fgrep },
{ "fmt", b_fmt },
{ "fold", b_fold },
{ "getconf", b_getconf },
{ "grep", b_grep },
{ "head", b_head },
{ "id", b_id },
{ "join", b_join },
{ "ln", b_ln },
{ "logname", b_logname },
{ "md5sum", b_md5sum },
{ "mkdir", b_mkdir },
{ "mkfifo", b_mkfifo },
{ "mktemp", b_mktemp },
{ "mv", b_mv },
{ "paste", b_paste },
{ "pathchk", b_pathchk },
{ "pids", b_pids },
{ "readlink", b_readlink },
#ifdef ENABLE_PERFORMANCE_PARADOXON
{ "rev", b_rev },
#endif /* ENABLE_PERFORMANCE_PARADOXON */
{ "rm", b_rm },
{ "rmdir", b_rmdir },
{ "stty", b_stty },
#ifdef ENABLE_PERFORMANCE_PARADOXON
{ "sum", b_sum },
#endif /* ENABLE_PERFORMANCE_PARADOXON */
{ "sync", b_sync },
{ "tail", b_tail },
{ "tee", b_tee },
{ "tty", b_tty },
{ "uname", b_uname },
{ "uniq", b_uniq },
{ "wc", b_wc },
{ "xgrep", b_xgrep },
{ NULL, (int (*)(int, char **, void *))NULL }
};
static inline
const bfastpathrec *
find_bfastpathrec(const char *name)
{
unsigned int i;
signed int cmpres;
for (i = 0; fastpath_builtins[i].name != NULL; i++) {
cmpres = strcmp(fastpath_builtins[i].name, name);
if (cmpres == 0)
return (&fastpath_builtins[i]);
else if (cmpres > 0)
return (NULL);
}
return (NULL);
}
static inline
int
fastpath_builtin_main(const bfastpathrec *brec, int argc, char *argv[])
{
setlocale(LC_ALL, ""); /* calls |_ast_setlocale()| */
return ((*brec->func)(argc, argv, NULL));
}
/* Builtin script, original derived from alias.sh */
static const char *script = "\n"
/* Get name of builtin */
"typeset cmd=\"${0##*/}\"\n"
/*
* If the requested command is not an alias load it explicitly
* to make sure it is not bound to a path (those built-ins which
* are mapped via shell aliases point to commands which are
* "special shell built-ins" which cannot be bound to a specific
* PATH element) - otherwise we may execute the wrong command
* if an executable with the same name sits in a PATH element
* before /usr/bin (e.g. /usr/xpg4/bin/ls would be executed
* before /usr/bin/ls if the path was something like
* PATH=/usr/xpg4/bin:/usr/bin).
*/
"if [[ \"${cmd}\" != ~(Elr)(alias|unalias|command) ]] && "
"! alias \"${cmd}\" >/dev/null 2>&1 ; then\n"
"PATH='' builtin \"${cmd}\"\n"
"fi\n"
/* command is a keyword and needs to be handled separately */
"if [[ \"${cmd}\" == \"command\" ]] ; then\n"
"command \"$@\"\n"
"else\n"
#ifdef WORKAROUND_FOR_ALIAS_CRASH
/*
* Work around a crash in /usr/bin/alias when invalid options are
* passed (e.g. $ /usr/bin/alias -c #). The shell code will call
* an error handler which does a |longjmp()| but somehow the code
* failed to do the |setjmp()| before this point.
* Putting the "alias" command in a subshell avoids the crash.
* Real cause of the issue is under investigation and a fix be
* delivered with the next ast-ksh update.
*/
"( \"${cmd}\" \"$@\" )\n"
#else
"\"${cmd}\" \"$@\"\n"
#endif /* WORKAROUND_FOR_ALIAS_CRASH */
"fi\n"
"exitval=$?";
static inline
int
script_builtin_main(int argc, char *argv[])
{
int i;
Shell_t *shp;
Namval_t *np;
int exitval;
/*
* Create copy of |argv| array shifted by one position to
* emulate $ /usr/bin/sh <scriptname> <args1> <arg2> ... #.
* First position is set to "/usr/bin/sh" since other
* values may trigger special shell modes (e.g. *rsh* will
* trigger "restricted" shell mode etc.).
*/
char *xargv[argc+2];
xargv[0] = "/usr/bin/sh";
xargv[1] = "scriptname";
for (i = 0; i < argc; i++) {
xargv[i+1] = argv[i];
}
xargv[i+1] = NULL;
shp = sh_init(argc+1, xargv, 0);
if (!shp)
error(ERROR_exit(1), "shell initialisation failed.");
(void) sh_trap(script, 0);
np = nv_open("exitval", shp->var_tree, 0);
if (!np)
error(ERROR_exit(1), "variable %s not found.", "exitval");
exitval = (int)nv_getnum(np);
nv_close(np);
return (exitval);
}
int
main(int argc, char *argv[])
{
const char *progname;
const bfastpathrec *brec;
char execnamebuff[PATH_MAX+1];
/* Get program name */
if (pathprog(argv[0], execnamebuff, sizeof (execnamebuff)) <= 0)
error(ERROR_exit(1), "could not determinate exec name.");
progname = (const char *)strrchr(execnamebuff, '/');
if (progname != NULL) {
progname++;
}
else
{
progname = execnamebuff;
}
/* Execute command... */
if (brec = find_bfastpathrec(progname)) {
/* ... either via a fast path (calling the code directly) ... */
return (fastpath_builtin_main(brec, argc, argv));
}
else
{
/* ... or from within a full shell. */
return (script_builtin_main(argc, argv));
}
}
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