Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / kern / imgact_shell.c
CommitLineData
984263bc
MD
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: src/sys/kern/imgact_shell.c,v 1.21.2.2 2001/12/22 01:21:39 jwd Exp $
27 */
28
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/sysproto.h>
32#include <sys/exec.h>
33#include <sys/imgact.h>
34#include <sys/kernel.h>
35
36#if BYTE_ORDER == LITTLE_ENDIAN
37#define SHELLMAGIC 0x2123 /* #! */
38#else
39#define SHELLMAGIC 0x2321
40#endif
41
42/*
43 * Shell interpreter image activator. A interpreter name beginning
44 * at imgp->stringbase is the minimal successful exit requirement.
45 */
46int
47exec_shell_imgact(imgp)
48 struct image_params *imgp;
49{
50 const char *image_header = imgp->image_header;
51 const char *ihp, *line_endp;
52 char *interp;
53
54 /* a shell script? */
55 if (((const short *) image_header)[0] != SHELLMAGIC)
56 return(-1);
57
58 /*
59 * Don't allow a shell script to be the shell for a shell
60 * script. :-)
61 */
62 if (imgp->interpreted)
63 return(ENOEXEC);
64
65 imgp->interpreted = 1;
66
67 /*
68 * Copy shell name and arguments from image_header into string
69 * buffer.
70 */
71
72 /*
73 * Find end of line; return if the line > MAXSHELLCMDLEN long.
74 */
75 for (ihp = &image_header[2]; *ihp != '\n' && *ihp != '#'; ++ihp) {
76 if (ihp >= &image_header[MAXSHELLCMDLEN])
77 return(ENAMETOOLONG);
78 }
79 line_endp = ihp;
80
81 /* reset for another pass */
82 ihp = &image_header[2];
83
84 /* Skip over leading spaces - until the interpreter name */
85 while ((*ihp == ' ') || (*ihp == '\t')) ihp++;
86
87 /* copy the interpreter name */
88 interp = imgp->interpreter_name;
89 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t'))
90 *interp++ = *ihp++;
91 *interp = '\0';
92
93 /* Disallow a null interpreter filename */
94 if (*imgp->interpreter_name == '\0')
95 return(ENOEXEC);
96
97 /* reset for another pass */
98 ihp = &image_header[2];
99
100 /* copy the interpreter name and arguments */
101 while (ihp < line_endp) {
102 /* Skip over leading spaces */
103 while ((*ihp == ' ') || (*ihp == '\t')) ihp++;
104
105 if (ihp < line_endp) {
106 /*
107 * Copy to end of token. No need to watch stringspace
108 * because this is at the front of the string buffer
109 * and the maximum shell command length is tiny.
110 */
111 while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) {
112 *imgp->stringp++ = *ihp++;
113 imgp->stringspace--;
114 }
115
116 *imgp->stringp++ = 0;
117 imgp->stringspace--;
118
119 imgp->argc++;
120 }
121 }
122
123 imgp->argv0 = imgp->uap->fname;
124
125 return(0);
126}
127
128/*
129 * Tell kern_execve.c about it, with a little help from the linker.
130 */
131static struct execsw shell_execsw = { exec_shell_imgact, "#!" };
132EXEC_SET(shell, shell_execsw);