imgact_shell.c revision 885 
1/*
2 * Copyright (c) 1993, David Greenman
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by David Greenman
16 * 4. The name of the developer may be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 *	$Id: shell_imgact.c,v 1.1 1993/12/12 12:23:20 davidg Exp $
32 */
33
34#include "param.h"
35#include "systm.h"
36#include "resourcevar.h"
37#include "imgact.h"
38
39#define SHELLMAGIC	0x2123 /* #! */
40#define MAXSHELLCMDLEN	64
41
42/*
43 * Shell interpreter image activator. A interpreter name beginning
44 *	at iparams->stringbase is the minimal successful exit requirement.
45 */
46int
47exec_shell_imgact(iparams)
48	struct image_params *iparams;
49{
50	const char *image_header = iparams->image_header;
51	const char *ihp, *line_endp;
52	int length;
53	char *interp;
54	char **argv;
55
56	/* a shell script? */
57	if (((short *) image_header)[0] != SHELLMAGIC)
58		return(-1);
59
60	/*
61	 * Don't allow a shell script to be the shell for a shell
62	 *	script. :-)
63	 */
64	if (iparams->interpreted)
65		return(ENOEXEC);
66
67	iparams->interpreted = 1;
68
69	/*
70	 * Copy shell name and arguments from image_header into string
71	 *	buffer.
72	 */
73
74	/*
75	 * Find end of line; return if the line > MAXSHELLCMDLEN long.
76	 */
77	for (ihp = &image_header[2]; *ihp != '\n'; ++ihp) {
78		if (ihp >= &image_header[MAXSHELLCMDLEN])
79			return(ENOEXEC);
80	}
81	line_endp = ihp;
82
83	/* reset for another pass */
84	ihp = &image_header[2];
85
86	/* Skip over leading spaces - until the interpreter name */
87	while ((*ihp == ' ') || (*ihp == '\t')) ihp++;
88
89	/* copy the interpreter name */
90	interp = iparams->interpreter_name;
91	while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t'))
92		*interp++ = *ihp++;
93	*interp = '\0';
94
95	/* Disallow a null interpreter filename */
96	if (*iparams->interpreter_name == '\0')
97		return(ENOEXEC);
98
99	/* reset for another pass */
100	ihp = &image_header[2];
101
102	/* copy the interpreter name and arguments */
103	while (ihp < line_endp) {
104		/* Skip over leading spaces */
105		while ((*ihp == ' ') || (*ihp == '\t')) ihp++;
106
107		if (ihp < line_endp) {
108			/*
109			 * Copy to end of token. No need to watch stringspace
110			 *	because this is at the front of the string buffer
111			 *	and the maximum shell command length is tiny.
112			 */
113			while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) {
114				*iparams->stringp++ = *ihp++;
115				iparams->stringspace--;
116			}
117
118			*iparams->stringp++ = 0;
119			iparams->stringspace--;
120
121			iparams->argc++;
122		}
123	}
124
125	/* set argv[0] to point to original file name */
126	suword(iparams->uap->argv, (int)iparams->uap->fname);
127
128	return(0);
129}
130