shadow/libmisc/shell.c
2009-07-22 13:35:57 +00:00

103 lines
3.3 KiB
C

/*
* Copyright (c) 1989 - 1991, Julianne Frances Haugh
* Copyright (c) 1996 - 1998, Marek Michałkiewicz
* Copyright (c) 2003 - 2006, Tomasz Kłoczko
* Copyright (c) 2009 , Nicolas François
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#ident "$Id$"
#include <stdio.h>
#include <errno.h>
#include "prototypes.h"
#include "defines.h"
extern char **newenvp;
extern size_t newenvc;
/*
* shell - execute the named program
*
* shell begins by trying to figure out what argv[0] is going to
* be for the named process. The user may pass in that argument,
* or it will be the last pathname component of the file with a
* '-' prepended.
* Then, it executes the named file.
*/
int shell (const char *file, /*@null@*/const char *arg, char *const envp[])
{
char arg0[1024];
int err;
if (file == (char *) 0) {
errno = EINVAL;
return errno;
}
/*
* The argv[0]'th entry is usually the path name, but
* for various reasons the invoker may want to override
* that. So, we determine the 0'th entry only if they
* don't want to tell us what it is themselves.
*/
if (arg == (char *) 0) {
snprintf (arg0, sizeof arg0, "-%s", Basename ((char *) file));
arg = arg0;
}
/*
* First we try the direct approach. The system should be
* able to figure out what we are up to without too much
* grief.
*/
execle (file, arg, (char *) 0, envp);
err = errno;
if (access (file, R_OK|X_OK) == 0) {
/*
* Assume this is a shell script (with no shebang).
* Interpret it with /bin/sh
*/
execle (SHELL, "sh", "-", file, (char *)0, envp);
err = errno;
}
/*
* Obviously something is really wrong - I can't figure out
* how to execute this stupid shell, so I might as well give
* up in disgust ...
*/
snprintf (arg0, sizeof arg0, _("Cannot execute %s"), file);
errno = err;
perror (arg0);
return err;
}